Add release v1.6.2

Merge pull request #2501 from weaveworks/issues/2495-filter-empty-peers
Reject empty peers
2016-09-21 16:18:03 +01:00 · 2016-09-21 11:12:10 +01:00 · 2016-09-20 17:17:19 +01:00 · 2016-09-20 17:03:38 +01:00 · 2016-09-20 16:40:06 +01:00 · 2016-09-20 15:52:54 +01:00
310 changed files with 18119 additions and 16534 deletions
@@ -0,0 +1,2 @@
+--ignore-dir=vendor
+--ignore-dir=.pkg
@@ -25,6 +25,7 @@ _testmain.go
 *.prof
 profile.cov
 coverage.html
+.pkg

 # Emacs backup files
 *~
@@ -40,25 +41,25 @@ prog/weaveproxy/weaveproxy
 prog/sigproxy/sigproxy
 prog/weavewait/weavewait
 prog/weavewait/weavewait_noop
-prog/netcheck/netcheck
-prog/docker_tls_args/docker_tls_args
+prog/weavewait/weavewait_nomcast
+prog/weaveutil/weaveutil
+prog/plugin/plugin
 testing/cover/cover
 testing/runner/runner
 releases
-.weaver.uptodate
-.weavedns.uptodate
-.weaveexec.uptodate
-weave.tar
+.*.uptodate
+weave.tar.gz
 prog/weaveexec/weave
 prog/weaveexec/weavehosts
 prog/weaveexec/weaveproxy
 prog/weaveexec/weavewait
 prog/weaveexec/weavewait_noop
+prog/weaveexec/weavewait_nomcast
 prog/weaveexec/sigproxy
-prog/weaveexec/netcheck
-prog/weaveexec/docker_tls_args
+prog/weaveexec/weaveutil
 prog/weaveexec/docker*.tgz
 Vagrantfile.local
+test/tls/tls
 test/tls/*.pem
 test/coverage
 test/coverage.*
@@ -1,3 +1,78 @@
 [submodule "tools"]
 	path = tools
 	url = https://github.com/weaveworks/build-tools
+[submodule "vendor/github.com/vishvananda/netlink"]
+	path = vendor/github.com/vishvananda/netlink
+	url = https://github.com/vishvananda/netlink.git
+[submodule "vendor/github.com/gorilla/mux"]
+	path = vendor/github.com/gorilla/mux
+	url = https://github.com/gorilla/mux.git
+[submodule "vendor/github.com/gorilla/context"]
+	path = vendor/github.com/gorilla/context
+	url = https://github.com/gorilla/context.git
+[submodule "vendor/github.com/google/gopacket"]
+	path = vendor/github.com/google/gopacket
+	url = https://github.com/google/gopacket.git
+[submodule "vendor/github.com/weaveworks/go-odp"]
+	path = vendor/github.com/weaveworks/go-odp
+	url = https://github.com/weaveworks/go-odp.git
+[submodule "vendor/github.com/opencontainers/runc"]
+	path = vendor/github.com/opencontainers/runc
+	url = https://github.com/opencontainers/runc.git
+[submodule "vendor/github.com/fsouza/go-dockerclient"]
+	path = vendor/github.com/fsouza/go-dockerclient
+	url = https://github.com/fsouza/go-dockerclient.git
+[submodule "vendor/github.com/docker/libnetwork"]
+	path = vendor/github.com/docker/libnetwork
+	url = https://github.com/docker/libnetwork.git
+[submodule "vendor/github.com/docker/docker"]
+	path = vendor/github.com/docker/docker
+	url = https://github.com/docker/docker.git
+[submodule "vendor/github.com/Sirupsen/logrus"]
+	path = vendor/github.com/Sirupsen/logrus
+	url = https://github.com/Sirupsen/logrus.git
+[submodule "vendor/github.com/andybalholm/go-bit"]
+	path = vendor/github.com/andybalholm/go-bit
+	url = https://github.com/andybalholm/go-bit.git
+[submodule "vendor/github.com/miekg/dns"]
+	path = vendor/github.com/miekg/dns
+	url = https://github.com/miekg/dns.git
+[submodule "vendor/github.com/stretchr/testify"]
+	path = vendor/github.com/stretchr/testify
+	url = https://github.com/stretchr/testify.git
+[submodule "vendor/golang.org/x/crypto"]
+	path = vendor/golang.org/x/crypto
+	url = https://github.com/golang/crypto.git
+[submodule "vendor/github.com/docker/machine"]
+	path = vendor/github.com/docker/machine
+	url = https://github.com/docker/machine.git
+[submodule "vendor/github.com/weaveworks/mesh"]
+	path = vendor/github.com/weaveworks/mesh
+	url = https://github.com/weaveworks/mesh
+[submodule "vendor/github.com/vishvananda/netns"]
+	path = vendor/github.com/vishvananda/netns
+	url = https://github.com/vishvananda/netns.git
+[submodule "vendor/github.com/boltdb/bolt"]
+	path = vendor/github.com/boltdb/bolt
+	url = https://github.com/boltdb/bolt
+[submodule "vendor/github.com/weaveworks/go-checkpoint"]
+	path = vendor/github.com/weaveworks/go-checkpoint
+	url = https://github.com/weaveworks/go-checkpoint
+[submodule "vendor/github.com/hashicorp/go-cleanhttp"]
+	path = vendor/github.com/hashicorp/go-cleanhttp
+	url = http://github.com/hashicorp/go-cleanhttp
+[submodule "vendor/github.com/appc/cni"]
+	path = vendor/github.com/appc/cni
+	url = https://github.com/appc/cni
+[submodule "vendor/github.com/coreos/go-iptables"]
+	path = vendor/github.com/coreos/go-iptables
+	url = https://github.com/coreos/go-iptables
+[submodule "vendor/github.com/pkg/profile"]
+	path = vendor/github.com/pkg/profile
+	url = https://github.com/pkg/profile
+[submodule "vendor/github.com/j-keck/arping"]
+	path = vendor/github.com/j-keck/arping
+	url = https://github.com/j-keck/arping
+[submodule "vendor/github.com/aws/aws-sdk-go"]
+	path = vendor/github.com/aws/aws-sdk-go
+	url = https://github.com/aws/aws-sdk-go
@@ -1,28 +0,0 @@
-language: go
-sudo: false
-go:
-  - 1.4
-
-env:
-  - PATH="${PATH}:${HOME}/.local/bin"
-
-addons:
-  apt:
-    packages:
-    - libpcap-dev
-
-install:
-  - go clean -i net
-  - go install -tags netgo std
-  - go get github.com/golang/lint/golint
-  - pip install --user --upgrade gsutil
-  - bin/setup-ci-secrets $encrypted_5ba036e89377_key $encrypted_5ba036e89377_iv
-  - make travis
-  - go get ./...
-
-script:
-  - make tests
-
-after_success:
-  - go get github.com/mattn/goveralls
-  - test "${TRAVIS_PULL_REQUEST}" = "false" && site/build-and-publish.sh
@@ -1,3 +1,254 @@
+## Release 1.6.2
+
+Bug fixes and minor improvements
+
+* Fixed hang after stopping and restarting on Docker 1.12 #2469/#2502
+* Avoid an error on Google container images by checking for tx offload support #2504
+* Fixed an issue where the supplied peer list could be ignored when restarting after failure #2503/#2509
+* Check for empty peer name on launch #2495/#2501
+
+More details in the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.6.2).
+
+## Release 1.6.1
+
+Bug fixes and minor improvements
+
+* `weave ps` was occasionally failing to list allocated addresses of containers #2388/#2418/#2445
+* `weave launch[-router]` on 4.2 kernel would appear to succeed even if the fast datapath VXLAN UDP port was in use by a different process #2375/#2474
+* Launching the proxy would fail when the Docker daemon could not be detected #2457/#2424
+* The CNI plugin did not work with Apache Mesos #2394/#2442
+* Router stopped working after a restart in the AWSVPC mode #2381/#2409
+* Router crashed when the Docker API endpoint parameter was explicitly set to empty #2421/#2467
+* The CNI plugin did not work on recent versions of Docker for Mac #2434/#2442
+* The CNI plugin assigns an IP to the bridge if necessary, which avoids failures if `weave expose` has not run yet #2471
+* Distinguish peer name collisions from attempts to connect to self in logs #2460
+* Improve host clock skew detection message #2174
+* Improve the error message returned when executing `weave launch-plugin` without the router running #2293/#2416
+* The `create-bridge` subcommand was not enabled in the fast datapath mode #2464/2466
+* Allow users to omit `weave setup[-cni]` by initializing the CNI plugin on the `launch[-router]` subcommand #2435/#2442
+* Reduce verbosity of fast datapath miss event logs #1852/#2417
+* Include the `ipam` option in the help output of the `status` subcommand #2425/#2426
+* Remove a harmless duplication of the `--no-dns` parameter #2430
+* Internal refactoring
+* Improvements to testing and building
+* Improvements to the documentation
+
+More details in the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.6.1).
+
+## Release 1.6.0
+
+## Highlights
+
+* A new [AWS VPC](https://weave.works/docs/net/latest/using-weave/awsvpc/) mode
+  that leverages Amazon Virtual Private Cloud for near-native network
+  performance, as an alternative to the Sleeve and Fast Datapath
+  overlays
+* Docker 1.12 introduced some internal changes that made it
+  incompatible with previous version of Weave Net - this version
+  restores compatibility
+* An [operational guide](https://weave.works/docs/net/latest/operational-guide)
+  detailing best practices for deploying and operating Weave Net
+* Changes to the target peer list are remembered across restarts,
+  making it much easier to deploy resilient networks
+* The version checkpoint now transmits network mode (e.g. 'awsvpc')
+  and kernel/docker versions to us to inform and guide our development
+  efforts. See the [installation documentation](https://weave.works/docs/net/latest/installing-weave/)
+  for instructions on disabling the checkpoint feature.
+
+More details in the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.6.0).
+
+## Release 1.5.2
+
+Bug fixes and minor improvements
+
+* Weave Proxy did not flush the initial http header in the Docker event stream, which could cause Docker Swarm to show all nodes pending. #2306/#2311
+* When using the CNI plugin, if a container was removed and quickly replaced by another using the same IP address, other containers might be unable to contact it. Send an address resolution protocol message to update them. #2313
+* Avoid Docker hanging for 1 minute in `weave launch` if the plugin had not shut down cleanly #2286/#2292
+* Print an error message when Weave bridge mode is changed without `weave reset` #2304
+* Eliminate spurious warning message from IP allocator on plugin shutdown #2300/#2319
+* Display error message when address requested in a subnet that is too small (/31 or /32) #2282/#2321
+* Add short wait after `weave reset` to allow updates to reach peers #2280
+* Weave was occasionally unable to claim existing IP address immediately after launch #2275/#2281
+* Refactor some integration tests to run faster and more reliably #2291
+
+## Release 1.5.1
+
+Bug fixes and minor improvements
+
+* Persisted data that was rendered invalid by changing peer name or
+  allocation range is detected and removed automatically, preventing
+  crashes and hangs #2246/#2209/#2249
+* `weave rmpeer` persists the range takeover in case the peer on which
+  it was executed dies subsequently #2238
+* Launching a container with an explicit `WEAVE_CIDR` in the
+  allocation range now waits instead of erroring if the allocator
+  hasn't finished initialising #2232/#2265
+* Weave DNS now responds to AAAA queries with an empty answer section,
+  instead of NXDOMAIN which could be cached and block subsequent
+  resolution of A records #2244/#2252
+* Many improvements to the documentation.
+
+More details in the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.5.1).
+
+## Release 1.5.0
+
+## Highlights
+
+- A new [Container Network Interface](https://github.com/appc/cni#cni---the-container-network-interface) plugin.
+- This release is much more robust against unscheduled restarts,
+  because it persists key data to disk.
+- New configuration options that are useful when you create or
+  auto-scale larger networks.
+- Weave now periodically checks for updates (can be disabled)
+
+Plus many bug fixes and minor enhancements. More details below and in
+the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.5.0).
+
+## Release 1.4.6
+
+Fixes some issues encountered by our users.
+
+* Restarting a peer could leave stale entries in WeaveDNS
+  #1867/#2023/#2081
+* Weave proxy occasionally failing to attach any new containers
+  #2016/#2049
+
+Other fixes:
+
+* Resolved a crash when a restarting peer re-connected to a peer that
+  had not received the latest IPAM data #2083/#2092
+* Make IP address space available immediately after a dead peer is
+  removed #2068
+
+## Release 1.4.5
+
+Higher performance for multicast and broadcast traffic when using
+Weave's Fast Datapath
+
+* The flow rule to deliver broadcast and multicast packets in-kernel
+  was not created correctly, hence every such packet caused a
+  context-switch to the software router #2003/#2008
+
+Other fixes:
+
+* Remove DNS entries for containers that are being restarted by Docker
+  but are not live yet #1977/#1989
+* Don't let one failing allocation attempt prevent others from
+  succeeding; they could be in different subnets which are more
+  available #1996/#2001
+* Don't complain on second router launch on kernels that lack support
+  for Fast Datapath #1929/#1983
+* Fix build broken by change in libnetwork IPAM API #1984/#1985
+
+## Release 1.4.4
+
+Fixing a rather serious issue that slipped through our preparations
+for Docker 1.10:
+
+* Restarting Docker or rebooting your machine while the Weave Net
+  plugin is running causes Docker 1.10.0 to fail to start #1959/#1963
+
+Also one other small fix:
+
+* Avoid a hang when trying to use plugin and proxy at the same time
+  #1956/#1961
+
+## Release 1.4.3
+
+Preparing for Docker 1.10, plus some bug-fixes.
+
+* Avoid hang in Docker v1.10 on `docker volume ls` after `weave stop`,
+  `weave stop-plugin` or `weave reset` #1934/#1936
+* Fix "unexpected EOF" from Docker 1.10 on `docker exec` with Weave
+  proxy `--rewrite-inspect` enabled #1911/#1917
+* Avoid losing DNS entries and potentially double-allocating IP
+  Addresses allocated via plugin, on router restart; also extend
+  `weave ps` to show IP addresses allocated via plugin #1745/#1921
+* Stop creating lots of copies of `weavewait` program in Docker
+  volumes #1757/#1935
+* Prevent container starting prematurely when proxy in
+`--no-multicast-route` mode #1942/#1943
+* Log error message from plugin rather than crashing when weave not
+  running #1906/#1918
+* Warn, don't error, if unable to remove plugin network in 'weave
+  stop', to avoid breaking the usual upgrade or config change process
+  #1900/#1919
+* Don't crash if network conditions suggest only very small packets
+  will get through #1905/#1926
+* Cope with unexpected errors during route traversal when starting
+  container via proxy #1909/#1910/#1932
+
+## Release 1.4.2
+
+Bug-fixes and minor improvements.
+
+* A race condition in weavewait that would occasionally hang
+  containers at startup #1882/#1884
+* Having the plugin auto-restart prevents successful `weave launch` on
+  reboot #1869
+* Work round weave router failure on CoreOS 4.3 caused by kernel bug
+  #1854
+* `weave launch` would exit with error code on docker <1.9 #1851
+* Running `eval $(weave env)` multiple times would break `eval $(weave
+  env --restore)` #1824/#1825
+* Don't complain in `weave stop` about "Plugin is not running" when
+  plugin is not enabled #1840/#1841
+* `weave --local launch` would fail if utility program
+  `docker_tls_args` could not be found #1844
+* Improved error reporting when TLS arg detection fails #1843
+* Improve error reporting when docker isn't running #1845
+* Add `--trusted-subnets` usage to `weave` script #1842
+* weave run can hang under rare combinations of options #1858
+
+## Release 1.4.1
+
+This is a bug-fix release to cover a few issues that came up since the
+release of 1.4.0.
+
+* Weave would fail to launch when `$DOCKER_HOST` was set to a TCP socket secured with TLS #1820/#1822
+* Weave would fail to stop when run against Docker pre-1.9 #1815/#1817
+* Issue a warning instead of failing on `--with-dns` option to proxy, which was removed #1810/#1812
+* Make `weave version` show the plugin version #1797/#1813
+* Make `weave launch` show when the a container is restarting #1778/#1814
+* Make `weave launch` fail if the plugin is running, for consistency with router and proxy. #1818/#1819
+
+More details in the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.4.1).
+
+## Release 1.4.0
+
+**Highlights**
+
+* The Docker Network plugin can now operate without a cluster store, so it is now run by default.
+* You can now use the fast datapath over trusted links and Weave encryption over untrusted links, in the same network.
+
+Plus many bug fixes and minor enhancements. More details below and in
+the [change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.4.0).
+
+## Release 1.3.1
+
+**Highlights**
+
+* The minimum Docker version has been increased to 1.6 due to the
+  [upcoming deprecation of Dockerhub access](https://blog.docker.com/2015/10/docker-hub-deprecation-1-5/)
+  for old clients. From December 7th onwards previous versions of the
+  `weave` script will fail to pull down images from the hub; if you
+  are unable to upgrade to 1.3.1 immediately you can work around this
+  by running `weave --local setup` in conjunction with a compatible
+  Docker client installation
+* Docker networking plugin now works with older kernels and allows you
+  to configure the MTU
+
+More details in the
+[change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.3.1).
+
+## Release 1.3.0
+
+**Highlights**
+
+This release includes a Docker Plugin, so you have the option to use
+Weave Net that way. More details in the
+[change log](https://github.com/weaveworks/weave/issues?q=milestone%3A1.3.0).
+
 ## Release 1.2.1

 This release contains a number of bug fixes and minor
@@ -0,0 +1,32 @@
+Thanks for your interest in contributing to this project and for
+taking the time to read this guide.
+
+# Code of conduct
+
+**Be respectful:** disagreements between people are to be expected and are usually the sign of healthy debate and engagement. Disagreements can lead to frustration and even anger for some members. Turning to personal insults, intimidation or threatening behaviour does not improve the situation. Participants should thus take care to ensure all communications / interactions stay professional at all times.
+
+**Be considerate:** remember that the community has members with a diverse background, many of whom have English as a second language. What might appear impolite, may simply be a result of a lack of knowledge of the English language. Bear in mind that actions will have an impact on other community members and the project as a whole, so take potential consequences into account before pursuing a course of action.
+
+**Be forgiving:** humans are fallible and as such prone to make mistakes and inexplicably change their positions at times. Don't assume that other members are acting with malicious intent. Be prepared to forgive people who make mistakes and assist each other in learning from them. Playing a blame game doesn't help anyone.
+
+# Issues
+* Before reporting an issue make sure you search first if anybody has already reported a similar issue and whether or not it has been fixed.
+* Make sure your issue report sufficiently details the problem:
+ * If you set up weave in some way other than that described by our [main instructions](https://github.com/zettio/weave#installation), please mention that.
+ * Include step-by-step instructions to reproduce the issue.
+ * State the OS platform you are using, i.e. `uname -a`
+ * `iptables` rules and firewalls can have a great impact on any Linux network; please note whether you have set up any rules and/or are running a firewall on your machine(s).
+* If you want to tackle any open issue, make sure you let people know you are working on it.
+
+## Pull Requests
+* Please be generous describing your changes.
+* Although it is highly suggested to include tests, they are not a hard requirement in order to get your contributions accepted.
+* Keep pull requests small so core developers can review them quickly.
+* Keep each pull request focused on a specific topic.  If you have two things to change, create two pull requests. This helps reviewers to understand the meat of your contribution.
+
+## Workflow
+See [WorkingOnWeave](https://github.com/weaveworks/weave/wiki/WorkingOnWeave)
+
+# Acknowledgements
+
+Much of this taken from https://github.com/cloudescape/gowsdl/blob/master/CONTRIBUTING.md
@@ -176,7 +176,7 @@

   END OF TERMS AND CONDITIONS

-   Copyright 2014-2015 Weaveworks Ltd.
+   Copyright 2014-2016 Weaveworks Ltd.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -1,10 +1,14 @@
-PUBLISH=publish_weave publish_weaveexec
+PUBLISH=publish_weave publish_weaveexec publish_plugin

 .DEFAULT: all
-.PHONY: all update tests lint publish $(PUBLISH) clean clean-bin prerequisites build travis run-smoketests
+.PHONY: all exes testrunner update tests lint publish $(PUBLISH) clean clean-bin prerequisites build run-smoketests

 # If you can use docker without being root, you can do "make SUDO="
-SUDO=sudo
+SUDO=$(shell docker info >/dev/null 2>&1 || echo "sudo -E")
+BUILD_IN_CONTAINER=true
+RM=--rm
+RUN_FLAGS=-ti
+COVERAGE=

 DOCKERHUB_USER=weaveworks
 WEAVE_VERSION=git-$(shell git rev-parse --short=12 HEAD)
@@ -14,25 +18,33 @@ WEAVEPROXY_EXE=prog/weaveproxy/weaveproxy
 SIGPROXY_EXE=prog/sigproxy/sigproxy
 WEAVEWAIT_EXE=prog/weavewait/weavewait
 WEAVEWAIT_NOOP_EXE=prog/weavewait/weavewait_noop
-NETCHECK_EXE=prog/netcheck/netcheck
-DOCKERTLSARGS_EXE=prog/docker_tls_args/docker_tls_args
-RUNNER_EXE=testing/runner/runner
+WEAVEWAIT_NOMCAST_EXE=prog/weavewait/weavewait_nomcast
+WEAVEUTIL_EXE=prog/weaveutil/weaveutil
+PLUGIN_EXE=prog/plugin/plugin
+RUNNER_EXE=tools/runner/runner
+TEST_TLS_EXE=test/tls/tls

-EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(NETCHECK_EXE) $(DOCKERTLSARGS_EXE) $(RUNNER_EXE)
+EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(PLUGIN_EXE) $(TEST_TLS_EXE)

+BUILD_UPTODATE=.build.uptodate
 WEAVER_UPTODATE=.weaver.uptodate
 WEAVEEXEC_UPTODATE=.weaveexec.uptodate
+PLUGIN_UPTODATE=.plugin.uptodate
+WEAVEDB_UPTODATE=.weavedb.uptodate

-IMAGES_UPTODATE=$(WEAVER_UPTODATE) $(WEAVEEXEC_UPTODATE)
+IMAGES_UPTODATE=$(WEAVER_UPTODATE) $(WEAVEEXEC_UPTODATE) $(PLUGIN_UPTODATE) $(WEAVEDB_UPTODATE)

 WEAVER_IMAGE=$(DOCKERHUB_USER)/weave
 WEAVEEXEC_IMAGE=$(DOCKERHUB_USER)/weaveexec
+PLUGIN_IMAGE=$(DOCKERHUB_USER)/plugin
+BUILD_IMAGE=$(DOCKERHUB_USER)/weavebuild
+WEAVEDB_IMAGE=$(DOCKERHUB_USER)/weavedb

-IMAGES=$(WEAVER_IMAGE) $(WEAVEEXEC_IMAGE)
+IMAGES=$(WEAVER_IMAGE) $(WEAVEEXEC_IMAGE) $(PLUGIN_IMAGE) $(WEAVEDB_IMAGE)

-WEAVE_EXPORT=weave.tar
+WEAVE_EXPORT=weave.tar.gz

-WEAVEEXEC_DOCKER_VERSION=1.3.1
+WEAVEEXEC_DOCKER_VERSION=1.6.2
 DOCKER_DISTRIB=prog/weaveexec/docker-$(WEAVEEXEC_DOCKER_VERSION).tgz
 DOCKER_DISTRIB_URL=https://get.docker.com/builds/Linux/x86_64/docker-$(WEAVEEXEC_DOCKER_VERSION).tgz
 NETGO_CHECK=@strings $@ | grep cgo_stub\\\.go >/dev/null || { \
@@ -43,104 +55,139 @@ NETGO_CHECK=@strings $@ | grep cgo_stub\\\.go >/dev/null || { \
 	echo "    sudo go install -tags netgo std"; \
 	false; \
 }
-BUILD_FLAGS=-ldflags "-extldflags \"-static\" -X main.version $(WEAVE_VERSION)" -tags netgo
+BUILD_FLAGS=-i -ldflags "-extldflags \"-static\" -X main.version=$(WEAVE_VERSION)" -tags netgo

 PACKAGE_BASE=$(shell go list -e ./)

-all: $(WEAVE_EXPORT) $(RUNNER_EXE)
+all: $(WEAVE_EXPORT)
+testrunner: $(RUNNER_EXE) $(TEST_TLS_EXE)

-travis: $(EXES)
+$(WEAVER_EXE) $(WEAVEPROXY_EXE) $(WEAVEUTIL_EXE): common/*.go common/*/*.go net/*.go net/*/*.go
+$(WEAVER_EXE): router/*.go ipam/*.go ipam/*/*.go db/*.go nameserver/*.go prog/weaver/*.go
+$(WEAVEPROXY_EXE): proxy/*.go prog/weaveproxy/*.go
+$(WEAVEUTIL_EXE): prog/weaveutil/*.go net/*.go
+$(SIGPROXY_EXE): prog/sigproxy/*.go
+$(PLUGIN_EXE): prog/plugin/*.go plugin/*/*.go api/*.go common/*.go common/docker/*.go net/*.go
+$(TEST_TLS_EXE): test/tls/*.go
+$(WEAVEWAIT_NOOP_EXE): prog/weavewait/*.go
+$(WEAVEWAIT_EXE): prog/weavewait/*.go net/*.go
+$(WEAVEWAIT_NOMCAST_EXE): prog/weavewait/*.go net/*.go
+tests: tools/.git
+lint: tools/.git

-update:
-	go get -u -f -v -tags netgo $(addprefix ./,$(dir $(EXES)))
+ifeq ($(BUILD_IN_CONTAINER),true)

-$(WEAVER_EXE) $(WEAVEPROXY_EXE): common/*.go common/*/*.go net/*.go
+exes $(EXES) tests lint: $(BUILD_UPTODATE)
+	git submodule update --init
+	@mkdir -p $(shell pwd)/.pkg
+	$(SUDO) docker run $(RM) $(RUN_FLAGS) \
+	    -v $(shell pwd):/go/src/github.com/weaveworks/weave \
+		-v $(shell pwd)/.pkg:/go/pkg \
+		-e GOARCH -e GOOS -e CIRCLECI -e CIRCLE_BUILD_NUM -e CIRCLE_NODE_TOTAL -e CIRCLE_NODE_INDEX -e COVERDIR -e SLOW \
+		$(BUILD_IMAGE) COVERAGE=$(COVERAGE) WEAVE_VERSION=$(WEAVE_VERSION) $@
+
+else
+
+exes: $(EXES)
+
+$(WEAVER_EXE) $(WEAVEPROXY_EXE) $(PLUGIN_EXE):
 ifeq ($(COVERAGE),true)
-	$(eval COVERAGE_MODULES := $(shell (go list ./$(@D); go list -f '{{join .Deps "\n"}}' ./$(@D) | grep "^$(PACKAGE_BASE)/") | paste -s -d,))
-	go get -t -tags netgo ./$(@D)
+	$(eval COVERAGE_MODULES := $(shell (go list ./$(@D); go list -f '{{join .Deps "\n"}}' ./$(@D) | grep "^$(PACKAGE_BASE)/") | grep -v "^$(PACKAGE_BASE)/vendor/" | paste -s -d,))
 	go test -c -o ./$@ $(BUILD_FLAGS) -v -covermode=atomic -coverpkg $(COVERAGE_MODULES) ./$(@D)/
 else
-	go get -tags netgo ./$(@D)
 	go build $(BUILD_FLAGS) -o $@ ./$(@D)
 endif
 	$(NETGO_CHECK)

-$(NETCHECK_EXE): common/*.go common/*/*.go net/*.go
-	go get -tags netgo ./$(@D)
+$(WEAVEUTIL_EXE):
 	go build $(BUILD_FLAGS) -o $@ ./$(@D)
 	$(NETGO_CHECK)

-$(WEAVER_EXE): router/*.go ipam/*.go ipam/*/*.go nameserver/*.go prog/weaver/*.go
-$(WEAVEPROXY_EXE): proxy/*.go prog/weaveproxy/main.go
-$(NETCHECK_EXE): prog/netcheck/netcheck.go
+$(WEAVEWAIT_EXE):
+	go build $(BUILD_FLAGS) -tags "netgo iface mcast" -o $@ ./$(@D)
+	$(NETGO_CHECK)

-# Sigproxy and weavewait need separate rules as they fail the netgo check in
+$(WEAVEWAIT_NOMCAST_EXE):
+	go build $(BUILD_FLAGS) -tags "netgo iface" -o $@ ./$(@D)
+	$(NETGO_CHECK)
+
+# These programs need a separate rule as they fail the netgo check in
 # the main build stanza due to not importing net package
-$(SIGPROXY_EXE): prog/sigproxy/main.go
-$(WEAVEWAIT_EXE): prog/weavewait/*.go net/*.go
-$(RUNNER_EXE): testing/runner/runner.go
-$(DOCKERTLSARGS_EXE): prog/docker_tls_args/*.go
-
-$(WEAVEWAIT_EXE) $(SIGPROXY_EXE) $(RUNNER_EXE) $(DOCKERTLSARGS_EXE):
-	go get -tags netgo ./$(@D)
+$(SIGPROXY_EXE) $(TEST_TLS_EXE) $(WEAVEWAIT_NOOP_EXE):
 	go build $(BUILD_FLAGS) -o $@ ./$(@D)

-$(WEAVEWAIT_NOOP_EXE): prog/weavewait/*.go
-	go get -tags netgo ./$(@D)
-	go build $(BUILD_FLAGS) -tags noop -o $@ ./$(@D)
+tests:
+	./tools/test -no-go-get

-$(WEAVER_UPTODATE): prog/weaver/Dockerfile $(WEAVER_EXE)
-	$(SUDO) docker build -t $(WEAVER_IMAGE) prog/weaver
+lint:
+	./tools/lint -nocomment -notestpackage .
+
+endif
+
+$(BUILD_UPTODATE): build/*
+	$(SUDO) docker build -t $(BUILD_IMAGE) build/
 	touch $@

-$(WEAVEEXEC_UPTODATE): prog/weaveexec/Dockerfile $(DOCKER_DISTRIB) weave $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(NETCHECK_EXE) $(DOCKERTLSARGS_EXE)
+$(WEAVER_UPTODATE): prog/weaver/Dockerfile $(WEAVER_EXE)
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker build -t $(WEAVER_IMAGE) prog/weaver
+	touch $@
+
+$(WEAVEEXEC_UPTODATE): prog/weaveexec/Dockerfile prog/weaveexec/symlink $(DOCKER_DISTRIB) weave $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE)
 	cp weave prog/weaveexec/weave
 	cp $(SIGPROXY_EXE) prog/weaveexec/sigproxy
 	cp $(WEAVEPROXY_EXE) prog/weaveexec/weaveproxy
 	cp $(WEAVEWAIT_EXE) prog/weaveexec/weavewait
 	cp $(WEAVEWAIT_NOOP_EXE) prog/weaveexec/weavewait_noop
-	cp $(NETCHECK_EXE) prog/weaveexec/netcheck
-	cp $(DOCKERTLSARGS_EXE) prog/weaveexec/docker_tls_args
+	cp $(WEAVEWAIT_NOMCAST_EXE) prog/weaveexec/weavewait_nomcast
+	cp $(WEAVEUTIL_EXE) prog/weaveexec/weaveutil
 	cp $(DOCKER_DISTRIB) prog/weaveexec/docker.tgz
-	$(SUDO) docker build -t $(WEAVEEXEC_IMAGE) prog/weaveexec
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker build -t $(WEAVEEXEC_IMAGE) prog/weaveexec
+	touch $@
+
+$(PLUGIN_UPTODATE): prog/plugin/Dockerfile $(PLUGIN_EXE) $(WEAVEEXEC_UPTODATE)
+	$(SUDO) docker build -t $(PLUGIN_IMAGE) prog/plugin
+	touch $@
+
+$(WEAVEDB_UPTODATE): prog/weavedb/Dockerfile
+	$(SUDO) docker build -t $(WEAVEDB_IMAGE) prog/weavedb
 	touch $@

 $(WEAVE_EXPORT): $(IMAGES_UPTODATE)
-	$(SUDO) docker save $(addsuffix :latest,$(IMAGES)) > $@
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker save $(addsuffix :latest,$(IMAGES)) | gzip > $@

 $(DOCKER_DISTRIB):
 	curl -o $(DOCKER_DISTRIB) $(DOCKER_DISTRIB_URL)

-tests: tools/.git
-	tools/test
-
-lint: tools/.git
-	tools/lint -nocomment -notestpackage .
-
 tools/.git:
 	git submodule update --init

+$(RUNNER_EXE): tools/.git
+	make -C tools/runner
+
 $(PUBLISH): publish_%: $(IMAGES_UPTODATE)
-	$(SUDO) docker tag -f $(DOCKERHUB_USER)/$* $(DOCKERHUB_USER)/$*:$(WEAVE_VERSION)
-	$(SUDO) docker push   $(DOCKERHUB_USER)/$*:$(WEAVE_VERSION)
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker tag  $(DOCKERHUB_USER)/$* $(DOCKERHUB_USER)/$*:$(WEAVE_VERSION)
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker push $(DOCKERHUB_USER)/$*:$(WEAVE_VERSION)
 ifneq ($(UPDATE_LATEST),false)
-	$(SUDO) docker push   $(DOCKERHUB_USER)/$*:latest
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker push $(DOCKERHUB_USER)/$*:latest
 endif

 publish: $(PUBLISH)
+ifeq ($(PUBLISH_WEAVEDB),true)
+	$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker push   $(DOCKERHUB_USER)/weavedb:latest
+endif

 clean-bin:
-	-$(SUDO) docker rmi $(IMAGES)
-	go clean -r $(addprefix ./,$(dir $(EXES)))
-	rm -f $(EXES) $(IMAGES_UPTODATE) $(WEAVE_EXPORT)
+	-$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker rmi $(IMAGES)
+	rm -rf $(EXES) $(IMAGES_UPTODATE) $(WEAVE_EXPORT) .pkg

 clean: clean-bin
-	rm -rf test/tls/*.pem test/coverage.* test/coverage
+	-$(SUDO) DOCKER_HOST=$(DOCKER_HOST) docker rmi $(BUILD_IMAGE)
+	rm -rf test/tls/*.pem test/coverage.* test/coverage $(BUILD_UPTODATE)

 build:
 	$(SUDO) go clean -i net
 	$(SUDO) go install -tags netgo std
 	$(MAKE)

-run-smoketests: all
+run-smoketests: all testrunner
 	cd test && ./setup.sh && ./run_all.sh
@@ -1,3 +1,3 @@
 Weave
-Copyright 2014-2015 Weaveworks Ltd.
+Copyright 2014-2016 Weaveworks Ltd.
 This product includes software developed at Weaveworks Ltd.
@@ -1,174 +1,25 @@
-# Weave - weaving containers into applications
+# Weave Net - Weaving Containers into Applications

-[![Build Status](https://travis-ci.org/weaveworks/weave.svg?branch=master)](https://travis-ci.org/weaveworks/weave) [![Integration Tests](https://circleci.com/gh/weaveworks/weave/tree/master.svg?style=shield&circle-token=4933c7dabb3d0383e62117565cb9d16df7b1a811)](https://circleci.com/gh/weaveworks/weave) [![Coverage Status](https://coveralls.io/repos/weaveworks/weave/badge.svg)](https://coveralls.io/r/weaveworks/weave)
+[![Integration Tests](https://circleci.com/gh/weaveworks/weave/tree/master.svg?style=shield)](https://circleci.com/gh/weaveworks/weave)
+[![Coverage Status](https://coveralls.io/repos/weaveworks/weave/badge.svg)](https://coveralls.io/r/weaveworks/weave)
+[![Go Report Card](https://goreportcard.com/badge/github.com/weaveworks/weave)](https://goreportcard.com/report/github.com/weaveworks/weave)
+[![Slack Status](https://slack.weave.works/badge.svg)](https://slack.weave.works)
+[![Docker Pulls](https://img.shields.io/docker/pulls/weaveworks/weave.svg?maxAge=604800)](https://hub.docker.com/r/weaveworks/weave/)

 # About Weaveworks

-[Weaveworks](http://weave.works) is the company that develops Weave -
-the most productive way for developers to connect, observe and control
-Docker containers. To learn about our products, including getting
-started tutorials, visit our [website](http://weave.works) and
-[documentation](http://docs.weave.works) or continue to read about
-some of the more technical aspects of Weave in this readme.
+[Weaveworks](https://www.weave.works) is the company that delivers the most productive way for developers to connect, observe and control
+Docker containers.

-# Weave
+This repository contains [Weave Net](https://www.weave.works/products/weave-net/), the first product developed by Weaveworks, and with nearly 5 million downloads to date, it enables you to get started with Docker clusters and portable apps in a fraction of the time compared with other solutions.

-Weave creates a virtual network that connects Docker containers
-deployed across multiple hosts and enables their automatic discovery.
+Other products from Weaveworks include [Weave Scope](https://www.weave.works/products/weave-scope/), a powerful container monitoring tool that automatically maps Docker containers and their interactions, and [Weave Flux](https://www.weave.works/products/weave-flux/), a microservice router that automates the access of containers as services.

-![Weave Virtual Network](/docs/virtual-network.png?raw=true "Weave Virtual Network")
+# Weave Net

-Applications use the network just as if the containers were all
-plugged into the same network switch, with no need to configure port
-mappings, links, etc. Services provided by application containers on
-the weave network can be made accessible to the outside world,
-regardless of where those containers are running. Similarly, existing
-internal systems can be exposed to application containers irrespective
-of their location.
+Weave Net creates a virtual network that connects Docker containers across multiple hosts and enables their automatic discovery. With Weave Net, portable microservices-based applications consisting of multiple containers can run anywhere: on one host, multiple hosts or even across cloud providers and data centers. Applications use the network just as if the containers were all plugged into the same network switch, without having to configure port mappings, ambassadors or links.

-![Weave Deployment](/docs/deployment.png?raw=true "Weave Deployment")
+Services provided by application containers on the Weave network can be exposed to the outside world, regardless of where they are running. Similarly, existing internal systems can be opened to accept connections from application containers irrespective of their location.

-Weave can traverse firewalls and operate in partially connected
-networks. Traffic can be encrypted, allowing hosts to be connected
-across an untrusted network.
-
-With weave you can easily construct applications consisting of
-multiple containers, running anywhere.
-
-Weave works alongside Docker's existing (single host) networking
-capabilities, so these can continue to be used by containers.
-
-## Installation
-
-Ensure you are running Linux (kernel 3.8 or later) and have Docker
-(version 1.3.1 or later) installed. Then install weave with
-
-    sudo curl -L git.io/weave -o /usr/local/bin/weave
-    sudo chmod a+x /usr/local/bin/weave
-
-For usage on OSX (with Docker Machine) you first need to make sure
-that a VM is running and configured, as shown in [the Docker Machine
-documentation](https://docs.docker.com/installation/mac/#from-your-shell).
-Then you can launch weave directly from the OSX host.
-
-CoreOS users see [here](https://github.com/fintanr/weave-gs/blob/master/coreos-simple/user-data) for an example of installing weave using cloud-config.
-
-Amazon ECS users see
-[here](https://github.com/weaveworks/guides/blob/master/aws-ecs/LATESTAMIs.md)
-for the latest Weave AMIs and
-[here](http://weave.works/guides/service-discovery-with-weave-aws-ecs.html) to get started with Weave on ECS.
-
-Weave respects the environment variable `DOCKER_HOST`, so you can run
-it locally to control a weave network on a remote host.
-
-## Quick Start Screencast
-
-<a href="https://youtu.be/kihQCCT1ykE" alt="Click to watch the screencast" target="_blank">
-  <img src="/docs/hello-screencast.png" />
-</a>
-
-## Example
-
-Say you have docker running on two hosts, accessible to each other as
-`$HOST1` and `$HOST2`, and want to deploy an application consisting of
-two containers, one on each host.
-
-On $HOST1 we run:
-
-    host1$ weave launch
-    host1$ eval $(weave env)
-    host1$ docker run --name a1 -ti ubuntu
-
-> NB: If the first command results in an error like
-> `http:///var/run/docker.sock/v1.19/containers/create: dial unix
-> /var/run/docker.sock: permission denied. Are you trying to connect
-> to a TLS-enabled daemon without TLS?` then you likely need to be
-> 'root' in order to connect to the Docker daemon. If so, run the
-> above and all subsequent commands in a *single* root shell (e.g. one
-> created with `sudo -s`). Do *not* prefix individual commands with
-> `sudo`, since some commands modify environment entries and hence
-> they all need to be executed from the same shell.
-
-The first line runs weave. The second line configures our environment
-so that containers launched via the docker command line are
-automatically attached to the weave network. Finally, we run our
-application container.
-
-That's it! If our application consists of more than one container on
-this host we simply launch them with `docker run` as appropriate.
-
-Next we repeat similar steps on `$HOST2`...
-
-    host2$ weave launch $HOST1
-    host2$ eval $(weave env)
-    host2$ docker run --name a2 -ti ubuntu
-
-The only difference, apart from the name of the application container,
-is that we tell our weave that it should peer with the weave on
-`$HOST1` (specified as the IP address or hostname, and optional
-`:port`, by which `$HOST2` can reach it). NB: if there is a firewall
-between `$HOST1` and `$HOST2`, you must permit traffic to the weave
-control port (TCP 6783) and data ports (UDP 6783/6784).
-
-Note that we could instead have told the weave on `$HOST1` to connect to
-`$HOST2`, or told both about each other. Order does not matter here;
-weave automatically (re)connects to peers when they become
-available. Also, we can tell weave to connect to multiple peers by
-supplying multiple addresses, separated by spaces. And we can
-[add peers dynamically](http://docs.weave.works/weave/latest_release/features.html#dynamic-topologies).
-
-Weave must be started once per host. The relevant container images are
-pulled down on demand, but if you wish you can preload them by running
-`weave setup` - this is particularly useful for automated deployments,
-and ensures that there are no delays during later operations.
-
-Now that we've got everything set up, let's see whether our containers
-can talk to each other...
-
-In the container started on `$HOST1`...
-
-    root@a1:/# ping -c 1 -q a2
-    PING a2.weave.local (10.40.0.2) 56(84) bytes of data.
-    --- a2.weave.local ping statistics ---
-    1 packets transmitted, 1 received, 0% packet loss, time 0ms
-    rtt min/avg/max/mdev = 0.341/0.341/0.341/0.000 ms
-
-Similarly, in the container started on `$HOST2`...
-
-    root@a2:/# ping -c 1 -q a1
-    PING a1.weave.local (10.32.0.2) 56(84) bytes of data.
-    --- a1.weave.local ping statistics ---
-    1 packets transmitted, 1 received, 0% packet loss, time 0ms
-    rtt min/avg/max/mdev = 0.366/0.366/0.366/0.000 ms
-
-So there we have it, two containers on separate hosts happily talking
-to each other.
-
-## Find out more
-
- * [Documentation homepage](http://docs.weave.works/weave/latest_release/)
- * [Getting Started Guides](http://weave.works/guides/)
- * [Features](http://docs.weave.works/weave/latest_release/features.html)
- * [Troubleshooting](http://docs.weave.works/weave/latest_release/troubleshooting.html)
- * [Building](http://docs.weave.works/weave/latest_release/building.html)
- * [How it works](http://docs.weave.works/weave/latest_release/how-it-works.html)
-
-## Contact Us
-
-Found a bug, want to suggest a feature, or have a question?  You can
-[File an issue](https://github.com/weaveworks/weave/issues).  And
-there is a [Weave Users Google
-Group](https://groups.google.com/a/weave.works/forum/#!forum/weave-users),
-which you can post to by email at weave-users@weave.works.  Or you can
-contact Weaveworks directly at help@weave.works. When reporting a
-bug, please include which version of weave you are running, as shown
-by `weave version`.
-
-Follow on Twitter:
-[@weaveworks](https://twitter.com/weaveworks).
-
-Read the Weave blog:
-[Weaveblog](http://weaveblog.com/).
-
-IRC:
-[#weavenetwork](https://botbot.me/freenode/weavenetwork/)
+* [Install Weave Net](https://www.weave.works/docs/net/latest/installing-weave/)
+* [Find out more about Weave Net](https://www.weave.works/products/weave-net/)
@@ -5,7 +5,7 @@ require './vagrant-common.rb'
 vm_ip = "172.16.0.3" # arbitrary private IP

 pkgs = %w(
-  docker-engine
+  docker-engine=1.10.2-0~wily
  aufs-tools
  build-essential
  ethtool
@@ -18,8 +18,7 @@ pkgs = %w(

 Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|

-  config.vm.box = "ubuntu/ubuntu-15.04-amd64"
-  config.vm.box_url = "https://cloud-images.ubuntu.com/vagrant/vivid/current/vivid-server-cloudimg-amd64-vagrant-disk1.box"
+  config.vm.box = "ubuntu/wily64"

  config.vm.network "private_network", ip: vm_ip
  config.vm.provider :virtualbox do |vb|
@@ -0,0 +1,22 @@
+package api
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func (client *Client) DNSDomain() (string, error) {
+	return client.httpVerb("GET", "/domain", nil)
+}
+
+func (client *Client) RegisterWithDNS(ID string, fqdn string, ip string) error {
+	data := url.Values{}
+	data.Add("fqdn", fqdn)
+	_, err := client.httpVerb("PUT", fmt.Sprintf("/name/%s/%s", ID, ip), data)
+	return err
+}
+
+func (client *Client) DeregisterWithDNS(ID string, ip string) error {
+	_, err := client.httpVerb("DELETE", fmt.Sprintf("/name/%s/%s", ID, ip), nil)
+	return err
+}
@@ -0,0 +1,63 @@
+package api
+
+import (
+	"fmt"
+	"net"
+)
+
+func (client *Client) ipamOp(ID string, op string) (*net.IPNet, error) {
+	ip, err := client.httpVerb(op, fmt.Sprintf("/ip/%s", ID), nil)
+	if err != nil {
+		return nil, err
+	}
+	return parseIP(ip)
+}
+
+// returns an IP for the ID given, allocating a fresh one if necessary
+func (client *Client) AllocateIP(ID string) (*net.IPNet, error) {
+	return client.ipamOp(ID, "POST")
+}
+
+func (client *Client) AllocateIPInSubnet(ID string, subnet *net.IPNet) (*net.IPNet, error) {
+	ip, err := client.httpVerb("POST", fmt.Sprintf("/ip/%s/%s", ID, subnet), nil)
+	if err != nil {
+		return nil, err
+	}
+	return parseIP(ip)
+}
+
+// returns an IP for the ID given, or nil if one has not been
+// allocated
+func (client *Client) LookupIP(ID string) (*net.IPNet, error) {
+	return client.ipamOp(ID, "GET")
+}
+
+// Claim a specific IP on behalf of the ID
+func (client *Client) ClaimIP(ID string, cidr *net.IPNet) error {
+	_, err := client.httpVerb("PUT", fmt.Sprintf("/ip/%s/%s", ID, cidr), nil)
+	return err
+}
+
+// release all IPs owned by an ID
+func (client *Client) ReleaseIPsFor(ID string) error {
+	_, err := client.httpVerb("DELETE", fmt.Sprintf("/ip/%s", ID), nil)
+	return err
+}
+
+func (client *Client) DefaultSubnet() (*net.IPNet, error) {
+	cidr, err := client.httpVerb("GET", fmt.Sprintf("/ipinfo/defaultsubnet"), nil)
+	if err != nil {
+		return nil, err
+	}
+	_, ipnet, err := net.ParseCIDR(cidr)
+	return ipnet, err
+}
+
+func parseIP(body string) (*net.IPNet, error) {
+	ip, ipnet, err := net.ParseCIDR(string(body))
+	if err != nil {
+		return nil, err
+	}
+	ipnet.IP = ip
+	return ipnet, nil
+}
@@ -0,0 +1,82 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+const (
+	WeaveHTTPHost = "127.0.0.1"
+	WeaveHTTPPort = 6784
+)
+
+type Client struct {
+	baseURL string
+	log     Logger
+}
+
+func (client *Client) httpVerb(verb string, url string, values url.Values) (string, error) {
+	url = client.baseURL + url
+	client.log.Debugf("weave %s to %s with %v", verb, url, values)
+	var body io.Reader
+	if values != nil {
+		body = strings.NewReader(values.Encode())
+	}
+	req, err := http.NewRequest(verb, url, body)
+	if err != nil {
+		return "", err
+	}
+	if values != nil {
+		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	rbody, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+	if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusNoContent {
+		return string(rbody), nil
+	}
+	return "", errors.New(resp.Status + ": " + string(rbody))
+}
+
+func NewClient(addr string, log Logger) *Client {
+	host := WeaveHTTPHost
+	port := fmt.Sprintf("%d", WeaveHTTPPort)
+	switch parts := strings.Split(addr, ":"); len(parts) {
+	case 0:
+	case 1:
+		if parts[0] != "" {
+			host = parts[0]
+		}
+	case 2:
+		if parts[0] != "" {
+			host = parts[0]
+		}
+		if parts[1] != "" {
+			port = parts[1]
+		}
+	default:
+		return &Client{baseURL: fmt.Sprintf("http://%s", addr), log: log}
+	}
+	return &Client{baseURL: fmt.Sprintf("http://%s:%s", host, port), log: log}
+}
+
+func (client *Client) Connect(remote string) error {
+	_, err := client.httpVerb("POST", "/connect", url.Values{"peer": {remote}})
+	return err
+}
+
+type Logger interface {
+	Infof(string, ...interface{})
+	Debugf(string, ...interface{})
+}
@@ -14,7 +14,8 @@ set -e
 START=${FIRST_WEAVE:-1}
 COUNT=${NUM_WEAVES:-28}
 FINISH=$((START+COUNT-1))
-PORT=6783
+
+SUBNET=192.168.7

 weavedir=$(dirname $0)/..

@@ -26,29 +27,42 @@ random_mac() {
    od -txC -An -N6 /dev/urandom | ( read a b c d e f && printf "%02x:$b:$c:$d:$e:$f" $((0x$a & ~1 | 2)) )
 }

+weave() {
+    i=$1
+    shift
+    WEAVE_CONTAINER_NAME=weave$i WEAVE_HTTP_ADDR=$SUBNET.$i:6784 $weavedir/weave "$@"
+}
+
 case "$1" in
    launch)
        shift 1
+        echo $(date -R) launching
+        ip link show multiweave >/dev/null 2>&1 || sudo ip link add name multiweave type bridge
        for i in $(seq $START $FINISH); do
-            WEAVE_CONTAINER_NAME=weave$i WEAVE_PORT=$((5000+i)) $weavedir/weave launch-router --iface '' --name $(random_mac) --nickname weave$i --port $PORT --no-dns "$@"
+            IP=$SUBNET.$i
+            sudo ip addr add $IP/24 dev multiweave
+            weave $i launch-router --datapath '' --iface '' --no-dns --host $IP \
+                --name $(random_mac) --nickname weave$i "$@"
        done
-        if [ $START -ne 1 ] ; then
-            status=$(docker inspect --format='{{.State.Running}} {{.NetworkSettings.IPAddress}}' weave$((START-1)))
-            PREV="${status#true }"
-        fi
+        echo $(date -R) connecting
+        [ $START -gt 1 ] || START=2
        for i in $(seq $START $FINISH); do
-            if [ -n "$PREV" ] ; then
-                echo connecting weave$i to $PREV
-                WEAVE_CONTAINER_NAME=weave$i $weavedir/weave connect $PREV
-            fi
-            status=$(docker inspect --format='{{.State.Running}} {{.NetworkSettings.IPAddress}}' weave$i)
-            PREV="${status#true }"
+            TO=$SUBNET.$((i-1))
+            echo connecting weave$i to $TO
+            weave $i connect $TO
        done
+        echo $(date -R) done
        ;;
    stop)
-        for i in $(seq $START $FINISH); do
+        for i in $(seq $FINISH -1 $START); do
+            IP=$SUBNET.$i
            echo Stopping weave$i
-            WEAVE_CONTAINER_NAME=weave$i $weavedir/weave stop-router
+            weave $i stop-router
+            sudo ip addr del $IP/24 dev multiweave || true
        done
+        [ -z "$(ip -4 -o addr show multiweave)" ] && sudo ip link del multiweave
+        ;;
+    *)
+            weave "$@"
        ;;
 esac
@@ -0,0 +1,46 @@
+#!/bin/bash
+
+set -e
+set -o pipefail
+
+PRODUCT=net
+
+fatal() {
+    echo "$@" >&2
+    exit 1
+}
+
+if [ ! -d .git ] ; then
+    fatal "Current directory is not a git clone"
+fi
+
+if ! BRANCH=$(git symbolic-ref --short HEAD) || [ -z "$BRANCH" ] ; then
+    fatal "Could not determine branch"
+fi
+
+case "$BRANCH" in
+    issues/*)
+        VERSION="${BRANCH#issues/}"
+        TAGS="$VERSION"
+        ;;
+    *)
+        if echo "$BRANCH" | grep -qE '^[0-9]+\.[0-9]+' ; then
+            DESCRIBE=$(git describe --match 'v*')
+            if ! VERSION=$(echo "$DESCRIBE" | grep -oP '(?<=^v)[0-9]+\.[0-9]+\.[0-9]+') ; then
+                fatal "Could not infer latest $BRANCH version from $DESCRIBE"
+            fi
+            TAGS="latest"
+        else
+            VERSION="$BRANCH"
+            TAGS="$VERSION"
+        fi
+        ;;
+esac
+
+for TAG in $TAGS ; do
+    echo ">>> Publishing $PRODUCT $VERSION to $1/docs/$PRODUCT/$TAG"
+    wordepress \
+        --url "$1" --user "$2" --password "$3" \
+        --product "$PRODUCT" --version "$VERSION" --tag "$TAG" \
+        publish site
+done
@@ -165,14 +165,14 @@ publish() {
    setup
    cd $PWD/$RELEASE_DIR

-    UPDATE_LATEST=false
+    IS_MAINLINE=false
    if [ "$RELEASE_TYPE" = 'MAINLINE' ] ; then
-        UPDATE_LATEST=true
+        IS_MAINLINE=true
    fi

    if [ "$RELEASE_TYPE" = 'PRERELEASE' ] ; then
        echo "== Tagging and pushing images on docker hub as user $DOCKERHUB_USER"
-        make UPDATE_LATEST=$UPDATE_LATEST SUDO=$SUDO WEAVE_VERSION=$VERSION DOCKERHUB_USER=$DOCKERHUB_USER publish
+        make UPDATE_LATEST=$IS_MAINLINE SUDO=$SUDO WEAVE_VERSION=$VERSION DOCKERHUB_USER=$DOCKERHUB_USER publish
        echo "** Docker images tagged and pushed"

        echo "== Publishing pre-release on GitHub"
@@ -204,7 +204,7 @@ publish() {
        echo '** Sanity checks OK for publishing tag' $LATEST_TAG as $DOCKERHUB_USER/weave:$VERSION

        echo "== Tagging and pushing images on docker hub as user $DOCKERHUB_USER"
-        make UPDATE_LATEST=$UPDATE_LATEST SUDO=$SUDO WEAVE_VERSION=$VERSION DOCKERHUB_USER=$DOCKERHUB_USER publish
+        make PUBLISH_WEAVEDB=$IS_MAINLINE UPDATE_LATEST=$IS_MAINLINE SUDO=$SUDO WEAVE_VERSION=$VERSION DOCKERHUB_USER=$DOCKERHUB_USER publish
        echo "** Docker images tagged and pushed"

        echo "== Publishing release on GitHub"
@@ -1,24 +1,8 @@
-FROM ubuntu
-
-RUN apt-get -y update && apt-get -y install --no-install-recommends ca-certificates apt-transport-https
-RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9
-RUN echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list
-RUN apt-get -y update && apt-get -y install --no-install-recommends build-essential git lxc-docker-1.3.1 mercurial libpcap-dev curl make pkg-config gcc bison flex python-requests
-
-# When doing a build in a container, "apt-get update" happens twice,
-# which can be a very significant overhead for incremental builds.
-# And it's unnecessary, because if any of the prerequisites do change,
-# the right thing to do is to rebuild the container image.  Rather
-# than suppressing the "apt-get update" commands explicitly, we clear
-# out sources.list so that 'apt-get update' doesn't do anything.
-RUN echo >/etc/apt/sources.list
-
-ENV GO_VERSION 1.4.2
-RUN curl -sSL https://golang.org/dl/go${GO_VERSION}.linux-amd64.tar.gz | tar -C /usr/local -xz
-ENV PATH /usr/local/go/bin:$PATH
-
-# So that sudo does not trample on PATH
-RUN sed -ie '/secure_path/d' /etc/sudoers
-
+FROM golang:1.5.2
+ENV GO15VENDOREXPERIMENT 1
+RUN apt-get update && apt-get install -y libpcap-dev python-requests time file
+RUN go get github.com/golang/lint/golint github.com/fzipp/gocyclo github.com/client9/misspell/cmd/misspell
+RUN go clean -i net && go install -tags netgo std
+RUN go install -race -tags netgo std
 COPY build.sh /
 ENTRYPOINT ["sh", "/build.sh"]
@@ -1,45 +1,28 @@
 #!/bin/sh
-set -e

-GOPATH=/home/go
-export GOPATH
+set -eu

 WEAVE_SRC=$GOPATH/src/github.com/weaveworks/weave

-if [ $# -eq 0 -o "$1" = "tests" ] ; then
-    # No arguments.  Expect that the weave repo will be bind-mounted
-    # into $GOPATH
-    if ! [ -e $WEAVE_SRC ] ; then
-        cat 2>&1 <<EOF
-No container arguments supplied, and nothing at ${WEAVE_SRC}.  Please
-either bind-mount the golang workspace containing weave with the
+if ! [ -e $WEAVE_SRC ] ; then
+    cat 2>&1 <<EOF
+Nothing at ${WEAVE_SRC}.  Please bind-mount the weave repo with the
 docker run -v option, e.g.:

-    $ docker run -v <host gopath>:${GOPATH} \\
-          -v /var/run/docker.sock:/var/run/docker.sock weaveworks/weave-build
-
-Or supply git clone arguments to retrieve it, e.g.:
-
-    $ docker run -v /var/run/docker.sock:/var/run/docker.sock \\
-          weaveworks/weave-build https://github.com/weaveworks/weave.git
+    $ cd weave
+	$ docker run -v $(pwd):/go/src/github.com/weaveworks/weave \\
+		weaveworks/weave-build
 EOF
-        exit 1
-    fi
-
-    # If we run make directly, any files created on the bind mount
-    # will have awkward ownership.  So we switch to a user with the
-    # same user and group IDs as source directory.  We have to set a
-    # few things up so that sudo works without complaining later on.
-    uid=$(stat --format="%u" $WEAVE_SRC)
-    gid=$(stat --format="%g" $WEAVE_SRC)
-    echo "weave:x:$uid:$gid::$WEAVE_SRC:/bin/sh" >>/etc/passwd
-    echo "weave:*:::::::" >>/etc/shadow
-    echo "weave	ALL=(ALL)	NOPASSWD: ALL" >>/etc/sudoers
-
-    su weave -c "PATH=$PATH make -C $WEAVE_SRC build"
-else
-    # There are arguments to pass to git-clone
-    mkdir -p ${WEAVE_SRC%/*}
-    git clone "$@" $WEAVE_SRC
-    make -C $WEAVE_SRC build
 fi
+
+# If we run make directly, any files created on the bind mount
+# will have awkward ownership.  So we switch to a user with the
+# same user and group IDs as source directory.  We have to set a
+# few things up so that sudo works without complaining later on.
+uid=$(stat --format="%u" $WEAVE_SRC)
+gid=$(stat --format="%g" $WEAVE_SRC)
+echo "weave:x:$uid:$gid::$WEAVE_SRC:/bin/sh" >>/etc/passwd
+echo "weave:*:::::::" >>/etc/shadow
+echo "weave	ALL=(ALL)	NOPASSWD: ALL" >>/etc/sudoers
+
+su weave -c "PATH=$PATH make -C $WEAVE_SRC BUILD_IN_CONTAINER=false $*"
@@ -10,69 +10,69 @@ machine:
  environment:
    GOPATH: /home/ubuntu:$GOPATH
    SRCDIR: /home/ubuntu/src/github.com/weaveworks/weave
-    PATH: $PATH:$HOME/.local/bin:$HOME/google-cloud-sdk/bin/
+    PATH: $PATH:$HOME/.local/bin
    CLOUDSDK_CORE_DISABLE_PROMPTS: 1
-    WEAVE_TEST: $HOME/docker/weave-test.tar

 dependencies:
  cache_directories:
    - "~/docker"
-  override:
-    - if [[ -e "$WEAVE_TEST" ]]; then
-        docker load -i $WEAVE_TEST;
-      else
-        docker build -t weaveworks/weave-build build;
-        docker build -t weaveworks/weave-test test/image;
-        mkdir -p $(dirname "$WEAVE_TEST");
-        docker save weaveworks/weave-test >$WEAVE_TEST;
-      fi
  post:
-    - sudo apt-get update
-    - sudo apt-get install bc jq
-    - pip install requests
-    - curl https://sdk.cloud.google.com | bash
+    - "sudo apt-get update && sudo apt-get install bc jq"
    - bin/setup-circleci-secrets "$SECRET_PASSWORD"
-    - mkdir -p $(dirname $SRCDIR)
-    - cp -r $(pwd)/ $SRCDIR
+    - "mkdir -p $(dirname $SRCDIR) && cp -r $(pwd)/ $SRCDIR"
+    - "cd $SRCDIR; git submodule update --init"
    - cd $SRCDIR/test; ./gce.sh make_template:
        parallel: false
+    - "cd $SRCDIR/build; ../tools/rebuild-image weaveworks/weavebuild . Dockerfile build.sh && touch $SRCDIR/.build.uptodate"
+    - "sudo chown -R ubuntu /usr/local/go"

 test:
  override:
    - cd $SRCDIR; make lint:
        parallel: true
-    - docker run -v /home/ubuntu:/home/go -e COVERDIR=test/coverage -e SLOW=true -e CIRCLECI -e CIRCLE_BUILD_NUM -e CIRCLE_NODE_TOTAL -e CIRCLE_NODE_INDEX weaveworks/weave-test:
+    - cd $SRCDIR; COVERDIR=test/coverage make RM= tests:
        parallel: true
-    - docker run -v /var/run/docker.sock:/run/docker.sock -v /home/ubuntu:/home/go -e COVERAGE=true weaveworks/weave-build:
+    - cd $SRCDIR; make COVERAGE=true RM= exes all:
        parallel: true
-    - cd $SRCDIR/test; ./gce.sh setup:
+    - cd $SRCDIR; make testrunner:
        parallel: true
-    - cd $SRCDIR/test; eval $(./gce.sh hosts); ./setup.sh:
+    - cd $SRCDIR/test; ./gce.sh setup && eval $(./gce.sh hosts) && ./setup.sh:
        parallel: true
    - cd $SRCDIR/test; eval $(./gce.sh hosts); export COVERAGE=true; ./run_all.sh:
        parallel: true
        timeout: 300
-    - cd $SRCDIR; make clean-bin:
-        parallel: true
-    - docker run -v /var/run/docker.sock:/run/docker.sock -v /home/ubuntu:/home/go weaveworks/weave-build:
-        parallel: true
  post:
    - cd $SRCDIR/test; ./gce.sh destroy:
        parallel: true
+    - test "$CIRCLE_NODE_INDEX" != "0" || (cd $SRCDIR/test; ./gen_coverage_reports.sh):
+        parallel: true

 teardown:
  pre:
-    - test "$CIRCLE_NODE_INDEX" != "0" || (cd $SRCDIR/test; ./gen_coverage_reports.sh):
-        parallel: true
    - test "$CIRCLE_NODE_INDEX" != "0" || (go get github.com/mattn/goveralls && goveralls -repotoken $COVERALLS_REPO_TOKEN -coverprofile=$SRCDIR/test/profile.cov -service=circleci || true):
        parallel: true
    - test "$CIRCLE_NODE_INDEX" != "0" || (cd $SRCDIR/test; cp coverage.* $CIRCLE_ARTIFACTS):
        parallel: true

 deployment:
+  release:
+    branch: /[0-9]+\.[0-9]+/
+    owner: weaveworks
+    commands:
+      - go get github.com/weaveworks/wordepress && cd /home/ubuntu/src/github.com/weaveworks/wordepress && git checkout v1.0.0 && cd cmd/wordepress && go get
+      - cd $SRCDIR; bin/publish-site "$WP_LIVE_URL" "$WP_LIVE_USER" "$WP_LIVE_PASSWORD"
  hub:
    branch: master
    owner: weaveworks
    commands:
      - docker login -e $DOCKER_EMAIL -u $DOCKER_USER -p $DOCKER_PASS
-      - cd $SRCDIR; make publish
+      - cd $SRCDIR; make clean-bin
+      - cd $SRCDIR; make exes publish
+#      - go get github.com/weaveworks/wordepress && cd /home/ubuntu/src/github.com/weaveworks/wordepress && git checkout v1.0.0 && cd cmd/wordepress && go get
+#      - cd $SRCDIR; bin/publish-site "$WP_DEV_URL" "$WP_DEV_USER" "$WP_DEV_PASSWORD"
+#  issues:
+#    branch: /.*/
+#    owner: weaveworks
+#    commands:
+#      - go get github.com/weaveworks/wordepress && cd /home/ubuntu/src/github.com/weaveworks/wordepress && git checkout v1.0.0 && cd cmd/wordepress && go get
+#      - cd $SRCDIR; bin/publish-site "$WP_DEV_URL" "$WP_DEV_USER" "$WP_DEV_PASSWORD"
@@ -1,82 +1,220 @@
 package docker

 import (
-	"github.com/fsouza/go-dockerclient"
-	. "github.com/weaveworks/weave/common"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	docker "github.com/fsouza/go-dockerclient"
+
+	"github.com/weaveworks/weave/common"
+)
+
+const (
+	InitialInterval = 1 * time.Second
+	MaxInterval     = 20 * time.Second
 )

 // An observer for container events
 type ContainerObserver interface {
 	ContainerStarted(ident string)
 	ContainerDied(ident string)
+	ContainerDestroyed(ident string)
 }

 type Client struct {
 	*docker.Client
 }

+type syncPair struct {
+	stop chan struct{}
+	done chan struct{}
+}
+
+type pendingStarts map[string]*syncPair
+
 // NewClient creates a new Docker client and checks we can talk to Docker
 func NewClient(apiPath string) (*Client, error) {
+	if apiPath != "" && !strings.Contains(apiPath, "://") {
+		apiPath = "tcp://" + apiPath
+	}
 	dc, err := docker.NewClient(apiPath)
 	if err != nil {
 		return nil, err
 	}
 	client := &Client{dc}

-	return client, client.checkWorking(apiPath)
+	return client, client.checkWorking()
 }

 func NewVersionedClient(apiPath string, apiVersionString string) (*Client, error) {
+	if !strings.Contains(apiPath, "://") {
+		apiPath = "tcp://" + apiPath
+	}
 	dc, err := docker.NewVersionedClient(apiPath, apiVersionString)
 	if err != nil {
 		return nil, err
 	}
 	client := &Client{dc}

-	return client, client.checkWorking(apiPath)
+	return client, client.checkWorking()
 }

-func (c *Client) checkWorking(apiPath string) error {
+func NewVersionedClientFromEnv(apiVersionString string) (*Client, error) {
+	dc, err := docker.NewVersionedClientFromEnv(apiVersionString)
+	if err != nil {
+		return nil, err
+	}
+	client := &Client{dc}
+
+	return client, client.checkWorking()
+}
+
+func (c *Client) checkWorking() error {
+	_, err := c.Version()
+	return err
+}
+
+func (c *Client) Info() string {
 	env, err := c.Version()
 	if err != nil {
-		return err
+		return fmt.Sprintf("Docker API error: %s", err)
 	}
-	Log.Infof("[docker] Using Docker API on %s: %v", apiPath, env)
-	return nil
+	return fmt.Sprintf("Docker API on %s: %v", c.Endpoint(), env)
+}
+
+func (c *Client) DockerVersion() string {
+	if env, err := c.Version(); err == nil {
+		if v, found := env.Map()["Version"]; found {
+			return v
+		}
+	}
+	return "unknown"
 }

 // AddObserver adds an observer for docker events
 func (c *Client) AddObserver(ob ContainerObserver) error {
-	events := make(chan *docker.APIEvents)
-	if err := c.AddEventListener(events); err != nil {
-		Log.Errorf("[docker] Unable to add listener to Docker API: %s", err)
-		return err
-	}
-
 	go func() {
-		for event := range events {
-			switch event.Status {
-			case "start":
-				id := event.ID
-				ob.ContainerStarted(id)
-			case "die":
-				id := event.ID
-				ob.ContainerDied(id)
+		pending := make(pendingStarts)
+		retryInterval := InitialInterval
+		for {
+			events := make(chan *docker.APIEvents)
+			if err := c.AddEventListener(events); err != nil {
+				c.errorf("Unable to add listener to Docker API: %s - retrying in %ds", err, retryInterval/time.Second)
+			} else {
+				start := time.Now()
+				for event := range events {
+					switch event.Status {
+					case "start":
+						pending.finish(event.ID)
+						pending.start(event.ID, c, ob)
+					case "die":
+						pending.finish(event.ID)
+						ob.ContainerDied(event.ID)
+					case "destroy":
+						pending.finish(event.ID)
+						ob.ContainerDestroyed(event.ID)
+					}
+				}
+				if time.Since(start) > retryInterval {
+					retryInterval = InitialInterval
+				}
+				c.errorf("Event listener channel closed - retrying subscription in %ds", retryInterval/time.Second)
+			}
+			time.Sleep(retryInterval)
+			retryInterval = retryInterval * 3 / 2
+			if retryInterval > MaxInterval {
+				retryInterval = MaxInterval
 			}
 		}
 	}()
 	return nil
 }

+// Docker sends a 'start' event before it has attempted to start the
+// container.  Delay notifying the observer until the container has a
+// pid, or we are told to stop when a 'die' event arrives.
+//
+// Note we always deliver the event, even if the container seems to
+// have gone away.
+func (pending pendingStarts) start(id string, c *Client, ob ContainerObserver) {
+	sync := syncPair{make(chan struct{}), make(chan struct{})}
+	pending[id] = &sync
+	go func() {
+		defer close(sync.done)
+		defer ob.ContainerStarted(id)
+		for {
+			if container, err := c.InspectContainer(id); err != nil || container.State.Pid != 0 {
+				return
+			}
+			select {
+			case <-sync.stop:
+				return
+			case <-time.After(200 * time.Millisecond):
+			}
+		}
+	}()
+}
+
+func (pending pendingStarts) finish(id string) {
+	if sync, found := pending[id]; found {
+		close(sync.stop)
+		<-sync.done
+		delete(pending, id)
+	}
+}
+
+func (c *Client) AllContainerIDs() ([]string, error) {
+	all, err := c.ListContainers(docker.ListContainersOptions{All: true})
+	if err != nil {
+		return nil, err
+	}
+	var ids []string
+	for _, c := range all {
+		ids = append(ids, c.ID)
+	}
+	return ids, nil
+}
+
 // IsContainerNotRunning returns true if we have checked with Docker that the ID is not running
 func (c *Client) IsContainerNotRunning(idStr string) bool {
 	container, err := c.InspectContainer(idStr)
 	if err == nil {
-		return !container.State.Running
+		return !container.State.Running || container.State.Restarting
 	}
 	if _, notThere := err.(*docker.NoSuchContainer); notThere {
 		return true
 	}
-	Log.Errorf("[docker] Could not check container status: %s", err)
+	c.errorf("Could not check container status: %s", err)
 	return false
 }
+
+// This is intended to find an IP address that we can reach the container on;
+// if it is on the Docker bridge network then that address; if on the host network
+// then localhost
+func (c *Client) GetContainerIP(nameOrID string) (string, error) {
+	info, err := c.InspectContainer(nameOrID)
+	if err != nil {
+		return "", err
+	}
+	if info.NetworkSettings.Networks != nil {
+		if bridgeNetwork, ok := info.NetworkSettings.Networks["bridge"]; ok {
+			return bridgeNetwork.IPAddress, nil
+		} else if _, ok := info.NetworkSettings.Networks["host"]; ok {
+			return "127.0.0.1", nil
+		}
+	} else if info.HostConfig.NetworkMode == "host" {
+		return "127.0.0.1", nil
+	}
+	if info.NetworkSettings.IPAddress == "" {
+		return "", errors.New("No IP address found for container " + nameOrID)
+	}
+	return info.NetworkSettings.IPAddress, nil
+}
+
+// logging
+
+func (c *Client) errorf(fmt string, args ...interface{}) {
+	common.Log.Errorf("[docker] "+fmt, args...)
+}
@@ -0,0 +1,18 @@
+package common
+
+import (
+	"net/http"
+)
+
+type loggingHandler struct {
+	next http.Handler
+}
+
+func (l *loggingHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	Log.Debugf("[http] %s %s", r.Method, r.URL.RequestURI())
+	l.next.ServeHTTP(w, r)
+}
+
+func LoggingHTTPHandler(h http.Handler) http.Handler {
+	return &loggingHandler{next: h}
+}
@@ -3,6 +3,7 @@ package common
 import (
 	"bytes"
 	"fmt"
+	"log"
 	"strings"

 	"github.com/Sirupsen/logrus"
@@ -52,3 +53,35 @@ func SetLogLevel(levelname string) {
 	}
 	Log.Level = level
 }
+
+func CheckFatal(e error) {
+	if e != nil {
+		Log.Fatal(e)
+	}
+}
+
+func CheckWarn(e error) {
+	if e != nil {
+		Log.Warnln(e)
+	}
+}
+
+// Adaptor type to go from Logrus to something expecting a standard library log.Logger
+type logLogger struct {
+	logger *logrus.Logger
+}
+
+// io.Writer interface
+func (l logLogger) Write(p []byte) (n int, err error) {
+	ln := len(p)
+	// Strip a trailing newline, because logrus formatter adds one
+	if ln > 0 && p[ln-1] == '\n' {
+		p = p[:ln-1]
+	}
+	l.logger.Info(string(p))
+	return ln, nil
+}
+
+func LogLogger() *log.Logger {
+	return log.New(logLogger{Log}, "", 0)
+}
@@ -1,4 +1,4 @@
-package router
+package odp

 import (
 	"fmt"
@@ -10,49 +10,45 @@ import (

 // ODP admin functionality

-func CreateDatapath(dpname string) (err error, supported bool) {
+func CreateDatapath(dpname string) (supported bool, err error) {
 	dpif, err := odp.NewDpif()
 	if err != nil {
 		if odp.IsKernelLacksODPError(err) {
-			return nil, false
+			return false, nil
 		}
-
-		return err, true
+		return true, err
 	}
-
 	defer dpif.Close()

 	dp, err := dpif.CreateDatapath(dpname)
 	if err != nil && !odp.IsDatapathNameAlreadyExistsError(err) {
-		return err, true
+		return true, err
 	}

 	// Pick an ephemeral port number to use in probing for vxlan
 	// support.
 	udpconn, err := net.ListenUDP("udp4", nil)
 	if err != nil {
-		return err, true
+		return true, err
 	}
+	defer udpconn.Close()

 	// we leave the UDP socket open, so creating a vxlan vport on
 	// the same port number should fail.  But that's fine: It's
 	// still sufficient to probe for support.
 	portno := uint16(udpconn.LocalAddr().(*net.UDPAddr).Port)
-	vpid, err := dp.CreateVport(odp.NewVxlanVportSpec(
-		fmt.Sprintf("vxlan-%d", portno), portno))
+	vpid, err := dp.CreateVport(odp.NewVxlanVportSpec(fmt.Sprintf("vxlan-%d", portno), portno))
 	if nlerr, ok := err.(odp.NetlinkError); ok {
 		if syscall.Errno(nlerr) == syscall.EAFNOSUPPORT {
 			dp.Delete()
-			return fmt.Errorf("kernel does not have Open vSwitch VXLAN support"), false
+			return false, fmt.Errorf("kernel does not have Open vSwitch VXLAN support")
 		}
 	}
-
 	if err == nil {
 		dp.DeleteVport(vpid)
 	}

-	udpconn.Close()
-	return nil, true
+	return true, nil
 }

 func DeleteDatapath(dpname string) error {
@@ -60,7 +56,6 @@ func DeleteDatapath(dpname string) error {
 	if err != nil {
 		return err
 	}
-
 	defer dpif.Close()

 	dp, err := dpif.LookupDatapath(dpname)
@@ -68,7 +63,6 @@ func DeleteDatapath(dpname string) error {
 		if odp.IsNoSuchDatapathError(err) {
 			return nil
 		}
-
 		return err
 	}

@@ -80,7 +74,6 @@ func AddDatapathInterface(dpname string, ifname string) error {
 	if err != nil {
 		return err
 	}
-
 	defer dpif.Close()

 	dp, err := dpif.LookupDatapath(dpname)
@@ -1,7 +1,16 @@
 package common

 import (
+	"fmt"
+	"net"
+	"os"
 	"strings"
+
+	"github.com/j-keck/arping"
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+
+	weavenet "github.com/weaveworks/weave/net"
 )

 // Assert test is true, panic otherwise
@@ -18,3 +27,159 @@ func ErrorMessages(errors []error) string {
 	}
 	return strings.Join(result, "\n")
 }
+
+type NetDev struct {
+	Name  string
+	MAC   net.HardwareAddr
+	CIDRs []*net.IPNet
+}
+
+// Search the network namespace of a process for interfaces matching a predicate
+// Note that the predicate is called while the goroutine is inside the process' netns
+func FindNetDevs(processID int, match func(link netlink.Link) bool) ([]NetDev, error) {
+	var netDevs []NetDev
+
+	ns, err := netns.GetFromPid(processID)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	defer ns.Close()
+
+	err = weavenet.WithNetNSUnsafe(ns, func() error {
+		return forEachLink(func(link netlink.Link) error {
+			if match(link) {
+				netDev, err := linkToNetDev(link)
+				if err != nil {
+					return err
+				}
+				netDevs = append(netDevs, netDev)
+			}
+			return nil
+		})
+	})
+
+	return netDevs, err
+}
+
+func forEachLink(f func(netlink.Link) error) error {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return err
+	}
+	for _, link := range links {
+		if err := f(link); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func linkToNetDev(link netlink.Link) (NetDev, error) {
+	addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return NetDev{}, err
+	}
+
+	netDev := NetDev{Name: link.Attrs().Name, MAC: link.Attrs().HardwareAddr}
+	for _, addr := range addrs {
+		netDev.CIDRs = append(netDev.CIDRs, addr.IPNet)
+	}
+	return netDev, nil
+}
+
+// ConnectedToBridgePredicate returns a function which is used to query whether
+// a given link is a veth interface which one end is connected to a bridge.
+// The returned function should be called from a container network namespace which
+// the bridge does NOT belong to.
+func ConnectedToBridgePredicate(bridgeName string) (func(link netlink.Link) bool, error) {
+	indexes := make(map[int]struct{})
+
+	// Scan devices in root namespace to find those attached to weave bridge
+	err := weavenet.WithNetNSLinkByPidUnsafe(1, bridgeName,
+		func(br netlink.Link) error {
+			return forEachLink(func(link netlink.Link) error {
+				if link.Attrs().MasterIndex == br.Attrs().Index {
+					peerIndex := link.Attrs().ParentIndex
+					if peerIndex == 0 {
+						// perhaps running on an older kernel where ParentIndex doesn't work.
+						// as fall-back, assume the indexes are consecutive
+						peerIndex = link.Attrs().Index - 1
+					}
+					indexes[peerIndex] = struct{}{}
+				}
+				return nil
+			})
+		})
+	if err != nil {
+		return nil, err
+	}
+
+	return func(link netlink.Link) bool {
+		_, isveth := link.(*netlink.Veth)
+		_, found := indexes[link.Attrs().Index]
+		return isveth && found
+	}, nil
+}
+
+func GetNetDevsWithPredicate(processID int, predicate func(link netlink.Link) bool) ([]NetDev, error) {
+	// Bail out if this container is running in the root namespace
+	nsToplevel, err := netns.GetFromPid(1)
+	if err != nil {
+		return nil, fmt.Errorf("unable to open root namespace: %s", err)
+	}
+	defer nsToplevel.Close()
+	nsContainr, err := netns.GetFromPid(processID)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("unable to open process %d namespace: %s", processID, err)
+	}
+	defer nsContainr.Close()
+	if nsToplevel.Equal(nsContainr) {
+		return nil, nil
+	}
+
+	return FindNetDevs(processID, predicate)
+}
+
+// Lookup the weave interface of a container
+func GetWeaveNetDevs(processID int) ([]NetDev, error) {
+	p, err := ConnectedToBridgePredicate("weave")
+	if err != nil {
+		return nil, err
+	}
+
+	return GetNetDevsWithPredicate(processID, p)
+}
+
+// Get the weave bridge interface.
+// NB: Should be called from the root network namespace.
+func GetBridgeNetDev(bridgeName string) (NetDev, error) {
+	link, err := netlink.LinkByName(bridgeName)
+	if err != nil {
+		return NetDev{}, err
+	}
+
+	return linkToNetDev(link)
+}
+
+// Do post-attach configuration of all veths we have created
+func ConfigureARPforVeths(processID int, prefix string) error {
+	_, err := FindNetDevs(processID, func(link netlink.Link) bool {
+		ifName := link.Attrs().Name
+		if strings.HasPrefix(ifName, prefix) {
+			weavenet.ConfigureARPCache(ifName)
+			if addrs, err := netlink.AddrList(link, netlink.FAMILY_V4); err == nil {
+				for _, addr := range addrs {
+					arping.GratuitousArpOverIfaceByName(addr.IPNet.IP, ifName)
+				}
+			}
+		}
+		return false
+	})
+	return err
+}
@@ -0,0 +1,84 @@
+package db
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+
+	"github.com/boltdb/bolt"
+)
+
+type DB interface {
+	Load(string, interface{}) (bool, error)
+	Save(string, interface{}) error
+}
+
+type BoltDB struct {
+	db *bolt.DB
+}
+
+var (
+	versionIdent       = []byte("version")
+	persistenceVersion = []byte{1, 0} // major.minor
+	topBucket          = []byte("top")
+)
+
+func NewBoltDB(dbPathname string) (*BoltDB, error) {
+	db, err := bolt.Open(dbPathname, 0660, nil)
+	if err != nil {
+		return nil, fmt.Errorf("[boltDB] Unable to open %s: %s", dbPathname, err)
+	}
+	// check the persistence version
+	err = db.Update(func(tx *bolt.Tx) error {
+		if top := tx.Bucket(topBucket); top == nil {
+			top, err := tx.CreateBucket(topBucket)
+			if err != nil {
+				return err
+			}
+			if err := top.Put(versionIdent, persistenceVersion); err != nil {
+				return err
+			}
+		} else {
+			if checkVersion := top.Get(versionIdent); checkVersion != nil {
+				if checkVersion[0] != persistenceVersion[0] {
+					return fmt.Errorf("[boltDB] Cannot use persistence file %s - version %x", dbPathname, checkVersion)
+				}
+			}
+		}
+		return nil
+	})
+	return &BoltDB{db: db}, err
+}
+
+func (d *BoltDB) Load(ident string, data interface{}) (bool, error) {
+	found := true
+	err := d.db.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket(topBucket)
+		v := b.Get([]byte(ident))
+		if v == nil {
+			found = false
+			return nil
+		}
+		reader := bytes.NewReader(v)
+		decoder := gob.NewDecoder(reader)
+		err := decoder.Decode(data)
+		return err
+	})
+	return found, err
+}
+
+func (d *BoltDB) Save(ident string, data interface{}) error {
+	return d.db.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket(topBucket)
+		buf := new(bytes.Buffer)
+		enc := gob.NewEncoder(buf)
+		if err := enc.Encode(data); err != nil {
+			return err
+		}
+		return b.Put([]byte(ident), buf.Bytes())
+	})
+}
+
+func (d *BoltDB) Close() error {
+	return d.db.Close()
+}
@@ -0,0 +1,170 @@
+# Overlay Method Selection
+
+Weave automatically selects the best working overlay implementation
+when connecting to a new peer. It does this by initiating both
+forwarders in parallel, eventually settling on the most preferred
+established forwarder at which point the other forwarder is shut down,
+assuming it had not failed already. In the event that the remaining
+forwarder fails at a later time (e.g. because of a heartbeat timeout)
+the control plane TCP connection will recycle allowing the selection
+algorithm to run again. By default fast datapath is preferred over
+Sleeve.
+
+# Local Bridging
+
+Unlike the weave bridge netdev used by Sleeve, the OVS datapath has no
+inherent bridging capability. Consequently fastdp implements an
+ethernet bridge in addition to the vxlan overlay, maintaining its own
+forwarding database by learning MAC addresses and dispatching
+broadcast, unicast & multicast traffic accordingly.
+
+# Short Peer IDs
+
+The router relies on having access to the source and destination peer
+when deciding how to forward packets. When the Sleeve overlay is in
+use this information is conveyed directly within the encapsulation by
+including the names of the peers in question, a solution not
+accommodated directly by the vxlan wire format. Fortunately vxlan does
+have a twenty four bit segment ID field in the header we can use to
+encode this data - the challenge is to identify peers uniquely with a
+twelve bit identifier instead of the seventeen bytes used by Sleeve.
+In practice this is achieved by peers adopting a random 'short ID' and
+resolving ownership collisions of same via the existing gossip
+mechanism.
+
+# Heartbeats via vxlan
+
+Heartbeats are implemented by sending an encapsulated ethernet frame
+with source and destination MAC addresses of `00:00:00:00:00:00` and a
+payload consisting of the connection UID and total ethernet frame
+length. The vxlan vport miss handler on the receiving side detects the
+all-zero addresses and acknowledges the heartbeat via the TCP control
+channel after validating the connection UID and frame length against
+their expected values.
+
+# PMTU Discovery
+
+The length of the heartbeat ethernet frame is set to the MTU of the
+datapath interface. In the event the vxlan packet is dropped or
+truncated, the heartbeat will not be acknowledged; this lack of
+acknowledgement will cause the peers to fall back to the Sleeve
+overlay, which has a more sophisticated dynamic mechanism for coping
+with low path MTUs.
+
+To avoid triggering this fallback in typical deployments, the datapath
+interface is statically configured with an MTU of 1410 bytes allowing
+it to work with most underlay network provider MTUs, including GCE at
+1460 bytes (the fifty byte difference accommodates the vxlan overhead).
+This value can be overridden by setting `WEAVE_MTU` at launch if
+necessary.
+
+# Virtual Ports
+
+There are three kinds of virtual port associated with the weave
+datapath:
+
+* `internal` - one of these is created automatically, named after the
+  datapath. It corresponds to the network interface of the same name
+  that appears on the host when the datapath is created; it is the
+  ingress/egress port for `weave expose`
+* `netdev` - one for each application container, corresponding to the
+  host end of the veth pair
+* `vxlan` - one for each UDP port on which we are listening for vxlan
+  encapsulated packets. Typically there is only one of these, but
+  there may be more in a network in which peers do not all use the same
+  port configuration
+
+# Misses and Flow Creation
+
+As mentioned above, the datapath has no inherent behaviour - any
+ingressing packet which does not match a flow is passed to a userspace
+miss handler. The miss handler is then responsible for a) instructing
+the datapath to take actions for the packet that caused the miss (for
+example by copying it to one or more ports) and optionally b)
+installing flow rules which will allow the datapath to act on similar
+packets in future without invoking the miss handler.
+
+At a high level the fast datapath implementation can be viewed as a
+set of miss handlers that determine what actions the OVS datapath
+should take based on router topology information, together with some
+additional machinery that manages the expiry of resulting flows when
+that state changes.
+
+When a miss handler is invoked, it has two pieces of context: a byte
+array containing the packet that triggered the miss, and a set of
+'flow keys' that have been extracted from the packet by the kernel
+module. The following flow keys are of interest to weave:
+
+* `InPort` - the identifier of the ingress virtual port
+* `Ethernet` - the source and destination MAC addresses of the
+  ethernet frame
+* `Tunnel` - tunnel identifier (see section on short peer IDs above),
+  and source/dest IPv4 addresses. Only present for ingress via a vxlan
+  vport
+
+Crucially, the router must use this information alone to determine
+which actions to take - this allows the specification of a flow which
+matches these keys and instructs the kernel to take action
+automatically in future without further userspace involvement.
+
+Two actions are of interest:
+
+* `Output` - output the packet to the specified vport
+* `SetTunnel` - update the effective vxlan tunnel parameters. Only
+  required prior to output from a vxlan vport
+
+It is possible to have multiple actions in a flow, so the router can
+for example create a single rule that copies broadcast traffic to all
+'local' vports (save the ingress vport obviously) as well as to vxlan
+vports for onward peers as dictated by the routing topology.
+
+Every flow specified by the router has the following characteristics:
+
+* An `InPort` key matching the ingress vport
+* A `Tunnel` key if the ingress vport is of type vxlan
+* An `Ethernet` key matching the source and destination MAC
+* A list of `Output` (for internal and netdev vports) and
+  `SetTunnel`+`Output` (for vxlan vports) actions
+
+Under certain circumstances the miss handler will instruct the
+datapath to execute a set of actions for a packet without creating a
+corresponding flow:
+
+* When broadcasting packets to discover the path to unknown
+  destination MACs. This condition is transient in the overwhelming
+  majority of cases and so the benefit of creating a flow is
+  outweighed by the need to invalidate it once the MAC is learned
+* When the packet also needs to be forwarded to one or more peers via
+  Sleeve. In this case the router needs to handle all subsequent
+  matching packets as there is no OVS flow action to do it without
+  userspace involvement
+
+# Flow Invalidation
+
+Once a flow has been created for a particular combination of keys, the
+miss handler will never again be invoked for matching packets. It is
+therefore extremely important that we detect events which invalidate
+existing flow actions:
+
+* Addition of netdev vports to the datapath
+* Route invalidation (topology change)
+* Short peer ID collision
+
+The response in each case is the same - delete all flows from the
+datapath, allowing them to be recreated taking into account the
+updated state.
+
+In addition to these event based invalidations there is an expiry
+process that executes every five minutes. This process enumerates all
+flows in the datapath, removing any which have not been used since the
+last check; this cleans up:
+
+* Flows referring to netdev vports which have been removed
+* Flows created by forwarders which have been stopped
+* Flows related to MAC addresses which have not communicated recently
+
+Flows keyed on tunnel IPv4 address do not need to be cleared when a
+peer appears to change IP address due to NAT; this will cause a miss
+resulting in a new flow, and the old flow will expire naturally via
+the timer mechanism.
+
@@ -210,11 +210,3 @@ reached the peer that does the `rmpeer`, then we get an inconsistent
 ring.  We could make it safe, up to partitions, by inquiring of every
 live peer what its view of the dead peer is, and making sure we use
 the latest info.)
-
-## Limitations
-
-Nothing is persisted. If one peer restarts it should receive gossip
-from other peers showing what it used to own, and in that case it can
-recover quite well. If, however, there are no peers left alive, or
-this peer cannot establish network communication with those that are,
-then it cannot recover.
@@ -6,7 +6,6 @@
 * Create a [github token for
  github-release](https://help.github.com/articles/creating-an-access-token-for-command-line-use/);
 set and export `$GITHUB_TOKEN` with this value
-* Update all dependencies with `make update`

 ## Release Types

@@ -63,9 +62,10 @@ This has the following effects:
 ## Draft Phase
 ### Push Version Tag Upstream

-First you must push your version tag upstream, so that an associated
-GitHub release may be created:
+First you must push your branch and version tag upstream, so that an
+associated GitHub release may be created:

+    git push git@github.com:weaveworks/weave
    git push git@github.com:weaveworks/weave $TAG

 N.B. if you're testing the release process, push to your fork
@@ -128,6 +128,16 @@ Finally, for **Mainline** releases only:

 * Images tagged `latest` are updated on DockerHub

+### Finish up
+
+* If not on master, merge branch into master and push to GitHub.
+* Close the [milestone](https://github.com/weaveworks/weave/milestones) in GitHub and create the next milestone
+* Update the `#weavenetwork` topic heading on freenode (requires 'chanops' permission)
+* For a mainline release vX.Y.0, create a release branch X.Y from the
+  tag and push to GitHub - this will result in X.Y.0 site docs being
+  published to https://www.weave.works
+* Add the new version of `weave-net` to the checkpoint system at
+  https://checkpoint-api.weave.works/admin

 ## Troubleshooting

@@ -9,7 +9,7 @@ The model is that each host has a service that is notified of
 hostnames and weave addresses for containers on the host.  Like IPAM,
 this service is embedded within the router.  It binds to
 the host bridge to answer DNS queries from local containers; for
-anything it can't answer, it uses the infomation in the host's
+anything it can't answer, it uses the information in the host's
 /etc/resolv.conf to query an 'fallback' server.

 The service is comprised of a DNS server, which answers all DNS queries
@@ -33,7 +33,7 @@ are re-broadcast around the cluster.
 The DNS server also listens to the Docker event stream, and removes
 entries for containers when they die.  Entries removed in this way are
 tombstoned, and the tombstone lazily broadcast around the cluster.
-After a short timeout the tombstones are independantly removed from
+After a short timeout the tombstones are independently removed from
 each host.


@@ -14,7 +14,8 @@ type allocateResult struct {
 type allocate struct {
 	resultChan       chan<- allocateResult
 	ident            string
-	r                address.Range // Range we are trying to allocate within
+	r                address.CIDR // Subnet we are trying to allocate within
+	isContainer      bool
 	hasBeenCancelled func() bool
 }

@@ -25,29 +26,36 @@ func (g *allocate) Try(alloc *Allocator) bool {
 		return true
 	}

-	if addr, found := alloc.lookupOwned(g.ident, g.r); found {
-		g.resultChan <- allocateResult{addr, nil}
+	if addrs := alloc.ownedInRange(g.ident, g.r.Range()); len(addrs) > 0 {
+		// If we had heard that this container died, resurrect it
+		delete(alloc.dead, g.ident) // delete is no-op if key not in map
+		g.resultChan <- allocateResult{addrs[0].Addr, nil}
 		return true
 	}

-	if !alloc.universe.Overlaps(g.r) {
-		g.resultChan <- allocateResult{0, fmt.Errorf("range %s out of bounds: %s", g.r, alloc.universe)}
+	if !alloc.universe.Range().Overlaps(g.r.Range()) {
+		g.resultChan <- allocateResult{err: fmt.Errorf("range %s out of bounds: %s", g.r, alloc.universe)}
 		return true
 	}

 	alloc.establishRing()

-	if ok, addr := alloc.space.Allocate(g.r); ok {
+	if ok, addr := alloc.space.Allocate(g.r.HostRange()); ok {
+		// If caller hasn't supplied a unique ID, file it under the IP address
+		// which lets the caller then release the address using DELETE /ip/address
+		if g.ident == "_" {
+			g.ident = addr.String()
+		}
 		alloc.debugln("Allocated", addr, "for", g.ident, "in", g.r)
-		alloc.addOwned(g.ident, addr)
+		alloc.addOwned(g.ident, address.MakeCIDR(g.r, addr), g.isContainer)
 		g.resultChan <- allocateResult{addr, nil}
 		return true
 	}

 	// out of space
-	donors := alloc.ring.ChoosePeersToAskForSpace(g.r.Start, g.r.End)
+	donors := alloc.ring.ChoosePeersToAskForSpace(g.r.Addr, g.r.Range().End)
 	for _, donor := range donors {
-		if err := alloc.sendSpaceRequest(donor, g.r); err != nil {
+		if err := alloc.sendSpaceRequest(donor, g.r.Range()); err != nil {
 			alloc.debugln("Problem asking peer", donor, "for space:", err)
 		} else {
 			alloc.debugln("Decided to ask peer", donor, "for space in range", g.r)
@@ -59,7 +67,7 @@ func (g *allocate) Try(alloc *Allocator) bool {
 }

 func (g *allocate) Cancel() {
-	g.resultChan <- allocateResult{0, &errorCancelled{"Allocate", g.ident}}
+	g.resultChan <- allocateResult{err: &errorCancelled{"Allocate", g.ident}}
 }

 func (g *allocate) ForContainer(ident string) bool {
@@ -22,6 +22,14 @@ const (

 func returnFalse() bool { return false }

+func (alloc *Allocator) SimplyAllocate(ident string, cidr address.CIDR) (address.Address, error) {
+	return alloc.Allocate(ident, cidr, true, returnFalse)
+}
+
+func (alloc *Allocator) SimplyClaim(ident string, cidr address.CIDR) error {
+	return alloc.Claim(ident, cidr, true, true, returnFalse)
+}
+
 func TestAllocFree(t *testing.T) {
 	const (
 		container1 = "abcdef"
@@ -37,40 +45,54 @@ func TestAllocFree(t *testing.T) {

 	alloc, subnet := makeAllocatorWithMockGossip(t, "01:00:00:01:00:00", universe, 1)
 	defer alloc.Stop()
-	_, cidr1, _ := address.ParseCIDR(subnet1)
-	_, cidr2, _ := address.ParseCIDR(subnet2)
+	cidr1, _ := address.ParseCIDR(subnet1)
+	cidr2, _ := address.ParseCIDR(subnet2)

 	alloc.claimRingForTesting()
-	addr1, err := alloc.Allocate(container1, cidr1.HostRange(), returnFalse)
+	addr1, err := alloc.SimplyAllocate(container1, cidr1)
 	require.NoError(t, err)
 	require.Equal(t, testAddr1, addr1.String(), "address")

-	addr2, err := alloc.Allocate(container1, cidr2.HostRange(), returnFalse)
+	addr2, err := alloc.SimplyAllocate(container1, cidr2)
 	require.NoError(t, err)
 	require.Equal(t, testAddr2, addr2.String(), "address")

+	addrs, err := alloc.Lookup(container1, subnet.Range())
+	require.NoError(t, err)
+	require.Equal(t, []address.CIDR{address.MakeCIDR(cidr1, addr1), address.MakeCIDR(cidr2, addr2)}, addrs)
+
 	// Ask for another address for a different container and check it's different
-	addr1b, _ := alloc.Allocate(container2, cidr1.HostRange(), returnFalse)
+	addr1b, _ := alloc.SimplyAllocate(container2, cidr1)
 	if addr1b.String() == testAddr1 {
 		t.Fatalf("Expected different address but got %s", addr1b.String())
 	}

 	// Ask for the first container again and we should get the same addresses again
-	addr1a, _ := alloc.Allocate(container1, cidr1.HostRange(), returnFalse)
+	addr1a, _ := alloc.SimplyAllocate(container1, cidr1)
 	require.Equal(t, testAddr1, addr1a.String(), "address")
-	addr2a, _ := alloc.Allocate(container1, cidr2.HostRange(), returnFalse)
+	addr2a, _ := alloc.SimplyAllocate(container1, cidr2)
 	require.Equal(t, testAddr2, addr2a.String(), "address")

 	// Now delete the first container, and we should get its addresses back
 	require.NoError(t, alloc.Delete(container1))
-	addr3, _ := alloc.Allocate(container3, cidr1.HostRange(), returnFalse)
+	addr3, _ := alloc.SimplyAllocate(container3, cidr1)
 	require.Equal(t, testAddr1, addr3.String(), "address")
-	addr4, _ := alloc.Allocate(container3, cidr2.HostRange(), returnFalse)
+	addr4, _ := alloc.SimplyAllocate(container3, cidr2)
 	require.Equal(t, testAddr2, addr4.String(), "address")

 	alloc.ContainerDied(container2)
+
+	// Resurrect
+	addr1c, err := alloc.SimplyAllocate(container2, cidr1)
+	require.NoError(t, err)
+	require.Equal(t, addr1b, addr1c, "address")
+
 	alloc.ContainerDied(container3)
-	require.Equal(t, address.Offset(spaceSize), alloc.NumFreeAddresses(subnet))
+	alloc.Encode() // sync up
+	// Move the clock forward and clear out the dead container
+	alloc.actionChan <- func() { alloc.now = func() time.Time { return time.Now().Add(containerDiedTimeout * 2) } }
+	alloc.actionChan <- func() { alloc.removeDeadContainers() }
+	require.Equal(t, address.Count(spaceSize+1), alloc.NumFreeAddresses(subnet.Range()))
 }

 func TestBootstrap(t *testing.T) {
@@ -95,7 +117,7 @@ func TestBootstrap(t *testing.T) {
 	ExpectBroadcastMessage(alloc1, nil) // alloc1 will try to form consensus
 	done := make(chan bool)
 	go func() {
-		alloc1.Allocate("somecontainer", subnet, returnFalse)
+		alloc1.Allocate("somecontainer", subnet, true, returnFalse)
 		done <- true
 	}()
 	time.Sleep(100 * time.Millisecond)
@@ -103,6 +125,7 @@ func TestBootstrap(t *testing.T) {

 	CheckAllExpectedMessagesSent(alloc1, alloc2)

+	// Check that tryPendingOps doesn't cause anything to happen here
 	alloc1.actionChan <- func() { alloc1.tryPendingOps() }
 	AssertNothingSent(t, done)

@@ -115,14 +138,24 @@ func TestBootstrap(t *testing.T) {
 	ExpectBroadcastMessage(alloc1, nil)
 	alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode())

-	// both nodes will get consensus now so initialize the ring
-	ExpectBroadcastMessage(alloc2, nil)
+	CheckAllExpectedMessagesSent(alloc1, alloc2)
+
+	// at this point, both nodes have seen each other, but don't have a valid proposal
+	// so there is another exchange of messages
 	ExpectBroadcastMessage(alloc2, nil)
 	alloc2.OnGossipBroadcast(alloc1.ourName, alloc1.Encode())

+	// we have consensus now so alloc1 will initialize the ring
+	ExpectBroadcastMessage(alloc1, nil)
+	alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode())
+
+	CheckAllExpectedMessagesSent(alloc1, alloc2)
+
+	// alloc2 receives the ring and does not reply
+	alloc2.OnGossipBroadcast(alloc1.ourName, alloc1.Encode())
+
 	CheckAllExpectedMessagesSent(alloc1, alloc2)

-	alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode())
 	// now alloc1 should have space

 	AssertSent(t, done)
@@ -135,42 +168,42 @@ func TestAllocatorClaim(t *testing.T) {
 		container1 = "abcdef"
 		container3 = "b01df00d"
 		universe   = "10.0.3.0/24"
-		testAddr1  = "10.0.3.2"
-		testAddr2  = "10.0.4.2"
+		testAddr1  = "10.0.3.2/24"
+		testAddr2  = "10.0.4.2/24"
 	)

-	allocs, _, subnet := makeNetworkOfAllocators(2, universe)
+	allocs, router, subnet := makeNetworkOfAllocators(2, universe)
+	defer stopNetworkOfAllocators(allocs, router)
 	alloc := allocs[1]
-	defer alloc.Stop()
-	addr1, _ := address.ParseIP(testAddr1)
+	addr1, _ := address.ParseCIDR(testAddr1)

 	// First claim should trigger "dunno, I'm going to wait"
-	err := alloc.Claim(container3, addr1, true)
+	err := alloc.SimplyClaim(container3, addr1)
 	require.NoError(t, err)

-	// Do one allocate to ensure paxos is all done
-	alloc.Allocate("unused", subnet, returnFalse)
+	alloc.Prime()
 	// Do an allocate on the other peer, which we will try to claim later
-	addrx, err := allocs[0].Allocate(container1, subnet, returnFalse)
+	addrx, err := allocs[0].Allocate(container1, subnet, true, returnFalse)
+	router.Flush()

 	// Now try the claim again
-	err = alloc.Claim(container3, addr1, true)
+	err = alloc.SimplyClaim(container3, addr1)
 	require.NoError(t, err)
 	// Check we get this address back if we try an allocate
-	addr3, _ := alloc.Allocate(container3, subnet, returnFalse)
-	require.Equal(t, testAddr1, addr3.String(), "address")
+	addr3, _ := alloc.SimplyAllocate(container3, subnet)
+	require.Equal(t, testAddr1, address.MakeCIDR(subnet, addr3).String(), "address")
 	// one more claim should still work
-	err = alloc.Claim(container3, addr1, true)
+	err = alloc.SimplyClaim(container3, addr1)
 	require.NoError(t, err)
 	// claim for a different container should fail
-	err = alloc.Claim(container1, addr1, true)
+	err = alloc.SimplyClaim(container1, addr1)
 	require.Error(t, err)
 	// claiming the address allocated on the other peer should fail
-	err = alloc.Claim(container1, addrx, true)
+	err = alloc.SimplyClaim(container1, address.MakeCIDR(subnet, addrx))
 	require.Error(t, err, "claiming address allocated on other peer should fail")
 	// Check an address outside of our universe
-	addr2, _ := address.ParseIP(testAddr2)
-	err = alloc.Claim(container1, addr2, true)
+	addr2, _ := address.ParseCIDR(testAddr2)
+	err = alloc.SimplyClaim(container1, addr2)
 	require.NoError(t, err)
 }

@@ -187,16 +220,13 @@ func (alloc *Allocator) pause() func() {
 }

 func TestCancel(t *testing.T) {
-	const (
-		CIDR = "10.0.1.7/26"
-	)
-
+	const cidr = "10.0.4.0/26"
 	router := gossip.NewTestRouter(0.0)

-	alloc1, subnet := makeAllocator("01:00:00:02:00:00", CIDR, 2)
+	alloc1, subnet := makeAllocator("01:00:00:02:00:00", cidr, 2)
 	alloc1.SetInterfaces(router.Connect(alloc1.ourName, alloc1))

-	alloc2, _ := makeAllocator("02:00:00:02:00:00", CIDR, 2)
+	alloc2, _ := makeAllocator("02:00:00:02:00:00", cidr, 2)
 	alloc2.SetInterfaces(router.Connect(alloc2.ourName, alloc2))
 	alloc1.claimRingForTesting(alloc1, alloc2)
 	alloc2.claimRingForTesting(alloc1, alloc2)
@@ -208,9 +238,9 @@ func TestCancel(t *testing.T) {
 	alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode())

 	// Get some IPs, so each allocator has some space
-	res1, _ := alloc1.Allocate("foo", subnet, returnFalse)
+	res1, _ := alloc1.Allocate("foo", subnet, true, returnFalse)
 	common.Log.Debugf("res1 = %s", res1.String())
-	res2, _ := alloc2.Allocate("bar", subnet, returnFalse)
+	res2, _ := alloc2.Allocate("bar", subnet, true, returnFalse)
 	common.Log.Debugf("res2 = %s", res2.String())
 	if res1 == res2 {
 		require.FailNow(t, "Error: got same ips!")
@@ -221,13 +251,13 @@ func TestCancel(t *testing.T) {
 	unpause := alloc2.pause()

 	// Use up all the IPs that alloc1 owns, so the allocation after this will prompt a request to alloc2
-	for i := 0; alloc1.NumFreeAddresses(subnet) > 0; i++ {
-		alloc1.Allocate(fmt.Sprintf("tmp%d", i), subnet, returnFalse)
+	for i := 0; alloc1.NumFreeAddresses(subnet.HostRange()) > 0; i++ {
+		alloc1.Allocate(fmt.Sprintf("tmp%d", i), subnet, true, returnFalse)
 	}
 	cancelChan := make(chan bool, 1)
 	doneChan := make(chan bool)
 	go func() {
-		_, ok := alloc1.Allocate("baz", subnet,
+		_, ok := alloc1.Allocate("baz", subnet, true,
 			func() bool {
 				select {
 				case <-cancelChan:
@@ -251,18 +281,18 @@ func TestCancel(t *testing.T) {

 func TestCancelOnDied(t *testing.T) {
 	const (
-		CIDR       = "10.0.1.7/26"
+		cidr       = "10.0.4.0/26"
 		container1 = "abcdef"
 	)

 	router := gossip.NewTestRouter(0.0)
-	alloc1, subnet := makeAllocator("01:00:00:02:00:00", CIDR, 2)
+	alloc1, subnet := makeAllocator("01:00:00:02:00:00", cidr, 2)
 	alloc1.SetInterfaces(router.Connect(alloc1.ourName, alloc1))
 	alloc1.Start()

 	doneChan := make(chan bool)
 	f := func() {
-		_, ok := alloc1.Allocate(container1, subnet, returnFalse)
+		_, ok := alloc1.Allocate(container1, subnet, true, returnFalse)
 		doneChan <- ok == nil
 	}

@@ -293,62 +323,80 @@ func TestGossipShutdown(t *testing.T) {
 	defer alloc.Stop()

 	alloc.claimRingForTesting()
-	alloc.Allocate(container1, subnet, returnFalse)
+	alloc.SimplyAllocate(container1, subnet)

 	alloc.Shutdown()

-	_, err := alloc.Allocate(container2, subnet, returnFalse) // trying to allocate after shutdown should fail
+	_, err := alloc.SimplyAllocate(container2, subnet) // trying to allocate after shutdown should fail
 	require.False(t, err == nil, "no address")

 	CheckAllExpectedMessagesSent(alloc)
 }

+func TestNoFrag(t *testing.T) {
+	const cidr = "10.0.4.0/22"
+	resultChan := make(chan int)
+	for i := 0; i < 100; i++ {
+		allocs, router, subnet := makeNetworkOfAllocators(3, cidr)
+		allocs[1].Allocate("foo", subnet, true, returnFalse)
+		allocs[2].Allocate("bar", subnet, true, returnFalse)
+		allocs[2].actionChan <- func() {
+			resultChan <- len(allocs[2].ring.Entries)
+		}
+		require.True(t, <-resultChan < 6, "excessive ring fragmentation")
+		stopNetworkOfAllocators(allocs, router)
+	}
+}
+
 func TestTransfer(t *testing.T) {
-	const (
-		cidr = "10.0.1.7/22"
-	)
+	const cidr = "10.0.4.0/22"
 	allocs, router, subnet := makeNetworkOfAllocators(3, cidr)
-	alloc1 := allocs[0]
-	alloc2 := allocs[1]
-	alloc3 := allocs[2] // This will be 'master' and get the first range
+	defer stopNetworkOfAllocators(allocs, router)
+	alloc0 := allocs[0]
+	alloc1 := allocs[1]
+	alloc2 := allocs[2]

-	_, err := alloc2.Allocate("foo", subnet, returnFalse)
+	_, err := alloc1.Allocate("foo", subnet, true, returnFalse)
 	require.True(t, err == nil, "Failed to get address")

-	_, err = alloc3.Allocate("bar", subnet, returnFalse)
+	_, err = alloc2.Allocate("bar", subnet, true, returnFalse)
 	require.True(t, err == nil, "Failed to get address")

+	// simulation of periodic gossip
 	alloc2.gossip.GossipBroadcast(alloc2.Gossip())
 	router.Flush()
-	alloc2.gossip.GossipBroadcast(alloc3.Gossip())
+	alloc1.gossip.GossipBroadcast(alloc1.Gossip())
 	router.Flush()
+
+	free1 := alloc1.NumFreeAddresses(subnet.Range())
+	free2 := alloc2.NumFreeAddresses(subnet.Range())
+
+	router.RemovePeer(alloc1.ourName)
 	router.RemovePeer(alloc2.ourName)
-	router.RemovePeer(alloc3.ourName)
-	alloc2.Stop()
-	alloc3.Stop()
-	router.Flush()
-	require.NoError(t, alloc1.AdminTakeoverRanges(alloc2.ourName.String()))
-	require.NoError(t, alloc1.AdminTakeoverRanges(alloc3.ourName.String()))
-	router.Flush()
-
-	require.Equal(t, address.Offset(1022), alloc1.NumFreeAddresses(subnet))
-
-	_, err = alloc1.Allocate("foo", subnet, returnFalse)
-	require.True(t, err == nil, "Failed to get address")
 	alloc1.Stop()
+	alloc2.Stop()
+	router.Flush()
+
+	require.Equal(t, free1+1, alloc0.AdminTakeoverRanges(alloc1.ourName.String()))
+	require.Equal(t, free2+1, alloc0.AdminTakeoverRanges(alloc2.ourName.String()))
+	router.Flush()
+
+	require.Equal(t, address.Count(1024), alloc0.NumFreeAddresses(subnet.Range()))
+
+	_, err = alloc0.Allocate("foo", subnet, true, returnFalse)
+	require.True(t, err == nil, "Failed to get address")
+	alloc0.Stop()
 }

 func TestFakeRouterSimple(t *testing.T) {
-	const (
-		cidr = "10.0.1.7/22"
-	)
-	allocs, _, subnet := makeNetworkOfAllocators(2, cidr)
-	defer stopNetworkOfAllocators(allocs)
+	const cidr = "10.0.4.0/22"
+	allocs, router, subnet := makeNetworkOfAllocators(2, cidr)
+	defer stopNetworkOfAllocators(allocs, router)

 	alloc1 := allocs[0]
 	//alloc2 := allocs[1]

-	_, err := alloc1.Allocate("foo", subnet, returnFalse)
+	_, err := alloc1.Allocate("foo", subnet, true, returnFalse)
 	require.NoError(t, err, "Failed to get address")
 }

@@ -359,10 +407,10 @@ func TestAllocatorFuzz(t *testing.T) {
 		nodes        = 5
 		maxAddresses = 1000
 		concurrency  = 5
-		cidr         = "10.0.1.7/22"
+		cidr         = "10.0.4.0/22"
 	)
-	allocs, _, subnet := makeNetworkOfAllocators(nodes, cidr)
-	defer stopNetworkOfAllocators(allocs)
+	allocs, router, subnet := makeNetworkOfAllocators(nodes, cidr)
+	defer stopNetworkOfAllocators(allocs, router)

 	// Test state
 	// For each IP issued we store the allocator
@@ -429,7 +477,7 @@ func TestAllocatorFuzz(t *testing.T) {
 		allocIndex := rand.Int31n(nodes)
 		alloc := allocs[allocIndex]
 		//common.Log.Infof("Allocate: asking allocator %d", allocIndex)
-		addr, err := alloc.Allocate(name, subnet, returnFalse)
+		addr, err := alloc.SimplyAllocate(name, subnet)

 		if err != nil {
 			panic(fmt.Sprintf("Could not allocate addr"))
@@ -486,7 +534,7 @@ func TestAllocatorFuzz(t *testing.T) {

 		//common.Log.Infof("Asking for %s (%s) on allocator %d again", res.name, addr, res.alloc)

-		newAddr, _ := alloc.Allocate(res.name, subnet, returnFalse)
+		newAddr, _ := alloc.SimplyAllocate(res.name, subnet)
 		oldAddr, _ := address.ParseIP(addr)
 		if newAddr != oldAddr {
 			panic(fmt.Sprintf("Got different address for repeat request for %s: %s != %s", res.name, newAddr, oldAddr))
@@ -506,8 +554,8 @@ func TestAllocatorFuzz(t *testing.T) {
 		allocIndex := rand.Int31n(nodes)
 		addressIndex := rand.Int31n(int32(subnet.Size()))
 		alloc := allocs[allocIndex]
-		addr := address.Add(subnet.Start, address.Offset(addressIndex))
-		err := alloc.Claim(name, addr, true)
+		addr := address.Add(subnet.Addr, address.Offset(addressIndex))
+		err := alloc.SimplyClaim(name, address.MakeCIDR(subnet, addr))
 		if err == nil {
 			noteAllocation(allocIndex, name, addr)
 		}
@@ -563,14 +611,36 @@ func TestAllocatorFuzz(t *testing.T) {
 	})
 }

-func TestGossipSkew(t *testing.T) {
-	alloc1, _ := makeAllocatorWithMockGossip(t, "01:00:00:01:00:00", "10.0.1.0/22", 2)
-	defer alloc1.Stop()
-	alloc2, _ := makeAllocatorWithMockGossip(t, "02:00:00:02:00:00", "10.0.1.0/22", 2)
-	alloc2.now = func() time.Time { return time.Now().Add(time.Hour * 2) }
-	defer alloc2.Stop()
+func TestSpaceRequest(t *testing.T) {
+	const (
+		container1 = "cont-1"
+		container2 = "cont-2"
+		universe   = "10.32.0.0/12"
+	)
+	allocs, router, subnet := makeNetworkOfAllocators(1, universe)
+	defer stopNetworkOfAllocators(allocs, router)
+	alloc1 := allocs[0]

-	if _, err := alloc1.OnGossipBroadcast(alloc2.ourName, alloc2.Encode()); err == nil {
-		t.Fail()
-	}
+	addr, err := alloc1.Allocate(container1, subnet, true, returnFalse)
+	require.Nil(t, err, "")
+	// free it again so the donation splits the range neatly
+	err = alloc1.Free(container1, addr)
+	require.Nil(t, err, "")
+	require.Equal(t, cidrRanges(universe), alloc1.OwnedRanges(), "")
+
+	// Start a new peer
+	alloc2, _ := makeAllocator("02:00:00:02:00:00", universe, 2)
+	alloc2.SetInterfaces(router.Connect(alloc2.ourName, alloc2))
+	alloc2.Start()
+	defer alloc2.Stop()
+	alloc2.Allocate(container2, subnet, true, returnFalse)
+
+	// Test whether the universe has been split into two equal halves (GH #2009)
+	require.Equal(t, cidrRanges("10.32.0.0/13"), alloc1.OwnedRanges(), "")
+	require.Equal(t, cidrRanges("10.40.0.0/13"), alloc2.OwnedRanges(), "")
+}
+
+func cidrRanges(s string) []address.Range {
+	c, _ := address.ParseCIDR(s)
+	return []address.Range{c.Range()}
 }
@@ -3,16 +3,19 @@ package ipam
 import (
 	"fmt"

+	"github.com/weaveworks/mesh"
+
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 type claim struct {
 	resultChan       chan<- error
 	ident            string
-	addr             address.Address
+	cidr             address.CIDR
+	isContainer      bool
 	noErrorOnUnknown bool
+	hasBeenCancelled func() bool
 }

 // Send an error (or nil for success) back to caller listening on resultChan
@@ -31,33 +34,41 @@ func (c *claim) sendResult(result error) {

 // Try returns true for success (or failure), false if we need to try again later
 func (c *claim) Try(alloc *Allocator) bool {
-	if !alloc.ring.Contains(c.addr) {
+	if c.hasBeenCancelled() {
+		c.Cancel()
+		return true
+	}
+
+	if !alloc.ring.Contains(c.cidr.Addr) {
 		// Address not within our universe; assume user knows what they are doing
-		alloc.infof("Ignored address %s claimed by %s - not in our universe", c.addr, c.ident)
+		alloc.infof("Address %s claimed by %s - not in our range", c.cidr, c.ident)
+		alloc.addOwned(c.ident, c.cidr, c.isContainer)
 		c.sendResult(nil)
 		return true
 	}

 	alloc.establishRing()

-	switch owner := alloc.ring.Owner(c.addr); owner {
+	// If we had heard that this container died, resurrect it
+	delete(alloc.dead, c.ident) // (delete is no-op if key not in map)
+
+	switch owner := alloc.ring.Owner(c.cidr.Addr); owner {
 	case alloc.ourName:
 		// success
-	case router.UnknownPeerName:
+	case mesh.UnknownPeerName:
 		// If our ring doesn't know, it must be empty.
+		alloc.infof("Claim %s for %s: is in the range %s, but the allocator is not initialized yet; will try later.",
+			c.cidr, c.ident, alloc.universe)
 		if c.noErrorOnUnknown {
-			alloc.infof("Claim %s for %s: address allocator still initializing; will try later.", c.addr, c.ident)
 			c.sendResult(nil)
-		} else {
-			c.sendResult(fmt.Errorf("%s is in the range %s, but the allocator is not initialized yet", c.addr, alloc.universe.AsCIDRString()))
 		}
 		return false
 	default:
-		alloc.debugf("requesting address %s from other peer %s", c.addr, owner)
-		err := alloc.sendSpaceRequest(owner, address.NewRange(c.addr, 1))
+		alloc.debugf("requesting address %s from other peer %s", c.cidr, owner)
+		err := alloc.sendSpaceRequest(owner, address.NewRange(c.cidr.Addr, 1))
 		if err != nil { // can't speak to owner right now
 			if c.noErrorOnUnknown {
-				alloc.infof("Claim %s for %s: %s; will try later.", c.addr, c.ident, err)
+				alloc.infof("Claim %s for %s: %s; will try later.", c.cidr, c.ident, err)
 				c.sendResult(nil)
 			} else { // just tell the user they can't do this.
 				c.deniedBy(alloc, owner)
@@ -66,32 +77,39 @@ func (c *claim) Try(alloc *Allocator) bool {
 		return false
 	}

+	if c.ident == "_" { // Special "I don't have a unique ID" identifier
+		c.ident = c.cidr.Addr.String()
+	}
 	// We are the owner, check we haven't given it to another container
-	switch existingIdent := alloc.findOwner(c.addr); existingIdent {
+	switch existingIdent := alloc.findOwner(c.cidr.Addr); existingIdent {
 	case "":
-		if err := alloc.space.Claim(c.addr); err == nil {
-			alloc.debugln("Claimed", c.addr, "for", c.ident)
-			alloc.addOwned(c.ident, c.addr)
+		if err := alloc.space.Claim(c.cidr.Addr); err == nil {
+			alloc.debugln("Claimed", c.cidr, "for", c.ident)
+			alloc.addOwned(c.ident, c.cidr, c.isContainer)
 			c.sendResult(nil)
 		} else {
 			c.sendResult(err)
 		}
 	case c.ident:
 		// same identifier is claiming same address; that's OK
+		alloc.debugln("Re-Claimed", c.cidr, "for", c.ident)
 		c.sendResult(nil)
+	case c.cidr.Addr.String():
+		// Address already allocated via "_" name
+		c.sendResult(fmt.Errorf("address %s already in use", c.cidr))
 	default:
 		// Addr already owned by container on this machine
-		c.sendResult(fmt.Errorf("address %s is already owned by %s", c.addr.String(), existingIdent))
+		c.sendResult(fmt.Errorf("address %s is already owned by %s", c.cidr.String(), existingIdent))
 	}
 	return true
 }

-func (c *claim) deniedBy(alloc *Allocator, owner router.PeerName) {
+func (c *claim) deniedBy(alloc *Allocator, owner mesh.PeerName) {
 	name, found := alloc.nicknames[owner]
 	if found {
 		name = " (" + name + ")"
 	}
-	c.sendResult(fmt.Errorf("address %s is owned by other peer %s%s", c.addr.String(), owner, name))
+	c.sendResult(fmt.Errorf("address %s is owned by other peer %s%s", c.cidr.String(), owner, name))
 }

 func (c *claim) Cancel() {
@@ -16,87 +16,120 @@ func badRequest(w http.ResponseWriter, err error) {
 	common.Log.Warningln("[allocator]:", err.Error())
 }

-func parseCIDR(w http.ResponseWriter, cidrStr string) (address.CIDR, bool) {
-	subnetAddr, cidr, err := address.ParseCIDR(cidrStr)
+func parseCIDR(w http.ResponseWriter, cidrStr string, net bool) (address.CIDR, bool) {
+	var cidr address.CIDR
+	var err error
+	if net {
+		cidr, err = ParseCIDRSubnet(cidrStr)
+	} else {
+		cidr, err = address.ParseCIDR(cidrStr)
+	}
 	if err != nil {
 		badRequest(w, err)
 		return address.CIDR{}, false
 	}
-	if cidr.Start != subnetAddr {
-		badRequest(w, fmt.Errorf("Invalid subnet %s - bits after network prefix are not all zero", cidrStr))
-		return address.CIDR{}, false
-	}
 	return cidr, true
 }

+func writeAddresses(w http.ResponseWriter, cidrs []address.CIDR) {
+	for i, cidr := range cidrs {
+		fmt.Fprint(w, cidr)
+		if i < len(cidrs)-1 {
+			w.Write([]byte{' '})
+		}
+	}
+}
+
+func hasBeenCancelled(dockerCli *docker.Client, closedChan <-chan bool, ident string, checkAlive bool) func() bool {
+	return func() bool {
+		select {
+		case <-closedChan:
+			return true
+		default:
+			res := checkAlive && dockerCli != nil && dockerCli.IsContainerNotRunning(ident)
+			checkAlive = false // we check only once; if the container dies later we learn about that through events
+			return res
+		}
+	}
+}
+
+func cancellationErr(w http.ResponseWriter, err error) bool {
+	if _, ok := err.(*errorCancelled); ok {
+		common.Log.Infoln("[allocator]:", err.Error())
+		fmt.Fprint(w, "cancelled")
+		return true
+	}
+	return false
+}
+
 func (alloc *Allocator) handleHTTPAllocate(dockerCli *docker.Client, w http.ResponseWriter, ident string, checkAlive bool, subnet address.CIDR) {
-	closedChan := w.(http.CloseNotifier).CloseNotify()
-	addr, err := alloc.Allocate(ident, subnet.HostRange(),
-		func() bool {
-			select {
-			case <-closedChan:
-				return true
-			default:
-				res := checkAlive && dockerCli != nil && dockerCli.IsContainerNotRunning(ident)
-				checkAlive = false // we check only once; if the container dies later we learn about that through events
-				return res
-			}
-		})
+	addr, err := alloc.Allocate(ident, subnet, checkAlive,
+		hasBeenCancelled(dockerCli, w.(http.CloseNotifier).CloseNotify(), ident, checkAlive))
 	if err != nil {
-		if _, ok := err.(*errorCancelled); ok { // cancellation is not really an error
-			common.Log.Infoln("[allocator]:", err.Error())
-			fmt.Fprint(w, "cancelled")
-			return
+		if !cancellationErr(w, err) {
+			badRequest(w, err)
 		}
-		badRequest(w, err)
 		return
 	}
-
 	fmt.Fprintf(w, "%s/%d", addr, subnet.PrefixLen)
 }

-// HandleHTTP wires up ipams HTTP endpoints to the provided mux.
-func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CIDR, dockerCli *docker.Client) {
-	router.Methods("PUT").Path("/ip/{id}/{ip}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		ident := vars["id"]
-		ipStr := vars["ip"]
-		noErrorOnUnknown := r.FormValue("noErrorOnUnknown") == "true"
-		if ip, err := address.ParseIP(ipStr); err != nil {
-			badRequest(w, err)
-			return
-		} else if err := alloc.Claim(ident, ip, noErrorOnUnknown); err != nil {
+func (alloc *Allocator) handleHTTPClaim(dockerCli *docker.Client, w http.ResponseWriter, ident string, cidr address.CIDR, checkAlive, noErrorOnUnknown bool) {
+	err := alloc.Claim(ident, cidr, checkAlive, noErrorOnUnknown,
+		hasBeenCancelled(dockerCli, w.(http.CloseNotifier).CloseNotify(), ident, checkAlive))
+	if err != nil {
+		if !cancellationErr(w, err) {
 			badRequest(w, fmt.Errorf("Unable to claim: %s", err))
-			return
 		}
+		return
+	}
+	w.WriteHeader(204)
+}

-		w.WriteHeader(204)
+// HandleHTTP wires up ipams HTTP endpoints to the provided mux.
+func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CIDR, tracker string, dockerCli *docker.Client) {
+	router.Methods("GET").Path("/ipinfo/defaultsubnet").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "%s", defaultSubnet)
+	})
+
+	router.Methods("PUT").Path("/ip/{id}/{ip}/{prefixlen}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		if cidr, ok := parseCIDR(w, vars["ip"]+"/"+vars["prefixlen"], false); ok {
+			ident := vars["id"]
+			checkAlive := r.FormValue("check-alive") == "true"
+			noErrorOnUnknown := r.FormValue("noErrorOnUnknown") == "true"
+			alloc.handleHTTPClaim(dockerCli, w, ident, cidr, checkAlive, noErrorOnUnknown)
+		}
+	})
+
+	router.Methods("GET").Path("/ring").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		alloc.Prime()
 	})

 	router.Methods("GET").Path("/ip/{id}/{ip}/{prefixlen}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		vars := mux.Vars(r)
-		if subnet, ok := parseCIDR(w, vars["ip"]+"/"+vars["prefixlen"]); ok {
-			addr, err := alloc.Lookup(vars["id"], subnet.HostRange())
+		if subnet, ok := parseCIDR(w, vars["ip"]+"/"+vars["prefixlen"], true); ok {
+			cidrs, err := alloc.Lookup(vars["id"], subnet.HostRange())
 			if err != nil {
 				http.NotFound(w, r)
 				return
 			}
-			fmt.Fprintf(w, "%s/%d", addr, subnet.PrefixLen)
+			writeAddresses(w, cidrs)
 		}
 	})

 	router.Methods("GET").Path("/ip/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		addr, err := alloc.Lookup(mux.Vars(r)["id"], defaultSubnet.HostRange())
+		addrs, err := alloc.Lookup(mux.Vars(r)["id"], defaultSubnet.HostRange())
 		if err != nil {
 			http.NotFound(w, r)
 			return
 		}
-		fmt.Fprintf(w, "%s/%d", addr, defaultSubnet.PrefixLen)
+		writeAddresses(w, addrs)
 	})

 	router.Methods("POST").Path("/ip/{id}/{ip}/{prefixlen}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		vars := mux.Vars(r)
-		if subnet, ok := parseCIDR(w, vars["ip"]+"/"+vars["prefixlen"]); ok {
+		if subnet, ok := parseCIDR(w, vars["ip"]+"/"+vars["prefixlen"], true); ok {
 			alloc.handleHTTPAllocate(dockerCli, w, vars["id"], r.FormValue("check-alive") == "true", subnet)
 		}
 	})
@@ -138,11 +171,11 @@ func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CID

 	router.Methods("DELETE").Path("/peer/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		ident := mux.Vars(r)["id"]
-		if err := alloc.AdminTakeoverRanges(ident); err != nil {
-			badRequest(w, err)
-			return
-		}
+		transferred := alloc.AdminTakeoverRanges(ident)
+		fmt.Fprintf(w, "%d IPs taken over from %s\n", transferred, ident)
+	})

-		w.WriteHeader(204)
+	router.Methods("GET").Path("/ipinfo/tracker").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, tracker)
 	})
 }
@@ -14,7 +14,6 @@ import (
 	"github.com/stretchr/testify/require"
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	wt "github.com/weaveworks/weave/testing"
 )

 func HTTPPost(t *testing.T, url string) string {
@@ -44,7 +43,7 @@ func listenHTTP(alloc *Allocator, subnet address.CIDR) int {
 	router.HandleFunc("/status", func(w http.ResponseWriter, r *http.Request) {
 		io.WriteString(w, fmt.Sprintln(alloc))
 	})
-	alloc.HandleHTTP(router, subnet, nil)
+	alloc.HandleHTTP(router, subnet, "", nil)

 	httpListener, err := net.Listen("tcp", ":0")
 	if err != nil {
@@ -81,7 +80,7 @@ func TestHttp(t *testing.T) {
 	)

 	alloc, _ := makeAllocatorWithMockGossip(t, "08:00:27:01:c3:9a", universe, 1)
-	_, cidr, _ := address.ParseCIDR(universe)
+	cidr, _ := address.ParseCIDR(universe)
 	port := listenHTTP(alloc, cidr)
 	alloc.claimRingForTesting()

@@ -123,7 +122,7 @@ func TestBadHttp(t *testing.T) {

 	alloc, _ := makeAllocatorWithMockGossip(t, "08:00:27:01:c3:9a", testCIDR1, 1)
 	defer alloc.Stop()
-	_, cidr, _ := address.ParseCIDR(testCIDR1)
+	cidr, _ := address.ParseCIDR(testCIDR1)
 	port := listenHTTP(alloc, cidr)

 	alloc.claimRingForTesting()
@@ -145,40 +144,30 @@ func TestBadHttp(t *testing.T) {
 }

 func TestHTTPCancel(t *testing.T) {
-	wt.RunWithTimeout(t, 2*time.Second, func() {
-		impTestHTTPCancel(t)
-	})
-}
-
-func impTestHTTPCancel(t *testing.T) {
 	var (
 		containerID = "deadbeef"
 		testCIDR1   = "10.0.3.0/29"
 	)

-	alloc, _ := makeAllocatorWithMockGossip(t, "08:00:27:01:c3:9a", testCIDR1, 1)
+	// Say quorum=2, so the allocate won't go ahead
+	alloc, _ := makeAllocatorWithMockGossip(t, "08:00:27:01:c3:9a", testCIDR1, 2)
 	defer alloc.Stop()
-	alloc.claimRingForTesting()
-	_, cidr, _ := address.ParseCIDR(testCIDR1)
+	ExpectBroadcastMessage(alloc, nil) // trying to form consensus
+	cidr, _ := address.ParseCIDR(testCIDR1)
 	port := listenHTTP(alloc, cidr)

-	// Stop the alloc so nothing actually works
-	unpause := alloc.pause()
-
 	// Ask the http server for a new address
-	done := make(chan *http.Response)
 	req, _ := http.NewRequest("POST", allocURL(port, testCIDR1, containerID), nil)
+	// On another goroutine, wait for a bit then cancel the request
 	go func() {
-		res, _ := http.DefaultClient.Do(req)
-		done <- res
+		time.Sleep(100 * time.Millisecond)
+		common.Log.Debug("Cancelling allocate")
+		http.DefaultTransport.(*http.Transport).CancelRequest(req)
 	}()

-	time.Sleep(100 * time.Millisecond)
-	fmt.Println("Cancelling allocate")
-	http.DefaultTransport.(*http.Transport).CancelRequest(req)
-	unpause()
-	res := <-done
+	res, _ := http.DefaultClient.Do(req)
 	if res != nil {
-		require.FailNow(t, "Error: Allocate returned non-nil")
+		body, _ := ioutil.ReadAll(res.Body)
+		require.FailNow(t, "Error: Allocate returned non-nil", string(body))
 	}
 }
@@ -0,0 +1,44 @@
+package paxos
+
+type Participant interface {
+	GossipState() GossipState
+	Update(from GossipState) bool
+	SetQuorum(uint)
+	Propose()
+	Think() bool
+	Consensus() (bool, AcceptedValue)
+	IsElector() bool
+}
+
+type Observer struct {
+}
+
+func NewObserver() Participant {
+	return &Observer{}
+}
+
+func (observer *Observer) GossipState() GossipState {
+	return nil
+}
+
+func (observer *Observer) Update(from GossipState) bool {
+	return false
+}
+
+func (observer *Observer) Propose() {
+}
+
+func (observer *Observer) SetQuorum(uint) {
+}
+
+func (observer *Observer) Think() bool {
+	return false
+}
+
+func (observer *Observer) Consensus() (bool, AcceptedValue) {
+	return false, AcceptedValue{}
+}
+
+func (observer *Observer) IsElector() bool {
+	return false
+}
@@ -1,7 +1,7 @@
 package paxos

 import (
-	"github.com/weaveworks/weave/router"
+	"github.com/weaveworks/mesh"
 )

 // The node identifier.  The use of the UID here is important: Paxos
@@ -9,8 +9,8 @@ import (
 // node does not restart and lose its Paxos state but claim to have
 // the same ID.
 type NodeID struct {
-	Name router.PeerName
-	UID  router.PeerUID
+	Name mesh.PeerName
+	UID  mesh.PeerUID
 }

 // note all fields exported in structs so we can Gob them
@@ -39,7 +39,7 @@ func (a ProposalID) valid() bool {
 }

 // For seeding IPAM, the value we want consensus on is a set of peer names
-type Value []router.PeerName
+type Value []mesh.PeerName

 // An AcceptedValue is a Value plus the proposal which originated that
 // Value.  The origin is not essential, but makes comparing
@@ -72,7 +72,7 @@ type Node struct {
 	knows  GossipState
 }

-func NewNode(name router.PeerName, uid router.PeerUID, quorum uint) *Node {
+func NewNode(name mesh.PeerName, uid mesh.PeerUID, quorum uint) *Node {
 	return &Node{
 		id:     NodeID{name, uid},
 		quorum: quorum,
@@ -80,6 +80,10 @@ func NewNode(name router.PeerName, uid router.PeerUID, quorum uint) *Node {
 	}
 }

+func (node *Node) SetQuorum(quorum uint) {
+	node.quorum = quorum
+}
+
 func (node *Node) GossipState() GossipState {
 	return node.knows
 }
@@ -124,6 +128,9 @@ func max(a uint, b uint) uint {
 // simply a matter of gossipping a new proposal that supersedes all
 // others.
 func (node *Node) Propose() {
+	if node.quorum == 0 {
+		panic("Paxos node.Propose() called with no quorum set")
+	}
 	// Find the highest round number around
 	round := uint(0)

@@ -223,7 +230,7 @@ func (node *Node) Think() bool {
 // about.  This is not necessarily all peer names, but it is at least
 // a quorum, and so good enough for seeding the ring.
 func (node *Node) pickValue() Value {
-	val := make([]router.PeerName, len(node.knows))
+	val := make([]mesh.PeerName, len(node.knows))
 	i := 0
 	for id := range node.knows {
 		val[i] = id.Name
@@ -234,6 +241,9 @@ func (node *Node) pickValue() Value {

 // Has a consensus been reached, based on the known claims of other nodes?
 func (node *Node) Consensus() (bool, AcceptedValue) {
+	if node.quorum == 0 {
+		return false, AcceptedValue{}
+	}
 	counts := map[ProposalID]uint{}

 	for _, claims := range node.knows {
@@ -250,14 +260,16 @@ func (node *Node) Consensus() (bool, AcceptedValue) {
 	return false, AcceptedValue{}
 }

+func (node *Node) IsElector() bool {
+	return true
+}
+
 type Status struct {
+	Elector    bool
 	KnownNodes int
 	Quorum     uint
 }

 func NewStatus(node *Node) *Status {
-	if node == nil {
-		return nil
-	}
-	return &Status{len(node.knows), node.quorum}
+	return &Status{true, len(node.knows), node.quorum}
 }
@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"

-	"github.com/weaveworks/weave/router"
+	"github.com/weaveworks/mesh"
 )

 type TestNode struct {
@@ -97,8 +97,8 @@ func makeRandomModel(params *TestParams, r *rand.Rand, t *testing.T) *Model {
 	}

 	for i := range m.nodes {
-		m.nodes[i].Node = NewNode(router.PeerName(i/2+1),
-			router.PeerUID(r.Int63()), m.quorum)
+		m.nodes[i].Node = NewNode(mesh.PeerName(i/2+1),
+			mesh.PeerUID(r.Int63()), m.quorum)
 		m.nodes[i].Propose()
 	}

@@ -172,8 +172,8 @@ func (m *Model) isolateNode(node *TestNode) {

 // Restart a node
 func (m *Model) restart(node *TestNode) {
-	node.Node = NewNode(router.PeerName(m.nextID),
-		router.PeerUID(m.r.Int63()), m.quorum)
+	node.Node = NewNode(mesh.PeerName(m.nextID),
+		mesh.PeerUID(m.r.Int63()), m.quorum)
 	m.nextID++
 	node.Propose()

@@ -300,14 +300,14 @@ func (m *Model) validate() {
 	for i := range m.nodes {
 		ok, val := m.nodes[i].Consensus()
 		if !ok {
-			//m.dump()
+			m.dump()
 			m.t.Fatal("Node doesn't know about consensus")
 		}

 		firstConsensus := m.nodes[i].firstConsensus
 		if firstConsensus.Origin.valid() &&
 			firstConsensus.Origin != val.Origin {
-			//m.dump()
+			m.dump()
 			m.t.Fatal("Consensus mismatch")
 		}

@@ -0,0 +1,24 @@
+package ipam
+
+type prime struct {
+	resultChan chan<- struct{}
+}
+
+func (c *prime) Try(alloc *Allocator) bool {
+	if !alloc.ring.Empty() {
+		close(c.resultChan)
+		return true
+	}
+
+	alloc.establishRing()
+
+	return false
+}
+
+func (c *prime) Cancel() {
+	close(c.resultChan)
+}
+
+func (c *prime) ForContainer(ident string) bool {
+	return false
+}
@@ -3,17 +3,18 @@ package ring
 import (
 	"sort"

+	"github.com/weaveworks/mesh"
+
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 // Entry represents entries around the ring
 type entry struct {
 	Token   address.Address // The start of this range
-	Peer    router.PeerName // Who owns this range
+	Peer    mesh.PeerName   // Who owns this range
 	Version uint32          // Version of this range
-	Free    address.Offset  // Number of free IPs in this range
+	Free    address.Count   // Number of free IPs in this range
 }

 func (e *entry) Equal(e2 *entry) bool {
@@ -21,7 +22,7 @@ func (e *entry) Equal(e2 *entry) bool {
 		e.Version == e2.Version
 }

-func (e *entry) update(peername router.PeerName, free address.Offset) {
+func (e *entry) update(peername mesh.PeerName, free address.Count) {
 	e.Peer = peername
 	e.Version++
 	e.Free = free
@@ -12,17 +12,21 @@ import (
 	"sort"
 	"time"

+	"github.com/weaveworks/mesh"
+
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

+type OnUpdate func(prev, curr []address.Range, local bool)
+
 // Ring represents the ring itself
 type Ring struct {
-	Start, End address.Address   // [min, max) tokens in this ring.  Due to wrapping, min == max (effectively)
-	Peer       router.PeerName   // name of peer owning this ring instance
-	Entries    entries           // list of entries sorted by token
-	Seeds      []router.PeerName // peers with which the ring was seeded
+	Start, End address.Address // [min, max) tokens in this ring.  Due to wrapping, min == max (effectively)
+	Peer       mesh.PeerName   // name of peer owning this ring instance
+	Entries    entries         // list of entries sorted by token
+	Seeds      []mesh.PeerName // peers with which the ring was seeded
+	onUpdate   OnUpdate
 }

 func (r *Ring) assertInvariants() {
@@ -39,40 +43,50 @@ var (
 	ErrTokenOutOfRange = errors.New("Token is out of range")
 	ErrDifferentSeeds  = errors.New("Received ring was seeded differently from ours!")
 	ErrDifferentRange  = errors.New("Received range differs from ours!")
-	ErrNewerVersion    = errors.New("Received new version for entry I own!")
-	ErrInvalidEntry    = errors.New("Received invalid state update!")
-	ErrEntryInMyRange  = errors.New("Received new entry in my range!")
-	ErrNotFound        = errors.New("No entries for peer found")
 )

+func errInconsistentEntry(mine, theirs *entry) error {
+	return fmt.Errorf("Inconsistent entries for %s: owned by %s but incoming message says %s", mine.Token, mine.Peer, theirs.Peer)
+}
+func errEntryInMyRange(theirs *entry) error {
+	return fmt.Errorf("Peer %s says it owns the IP range from %s, which I think I own", theirs.Peer, theirs.Token)
+}
+func errNewerVersion(mine, theirs *entry) error {
+	return fmt.Errorf("Received update for IP range I own at %s v%d: incoming message says owner %s v%d", mine.Token, mine.Version, theirs.Peer, theirs.Version)
+}
+
 func (r *Ring) checkInvariants() error {
-	if !sort.IsSorted(r.Entries) {
+	return r.checkEntries(r.Entries)
+}
+
+func (r *Ring) checkEntries(entries entries) error {
+	if !sort.IsSorted(entries) {
 		return ErrNotSorted
 	}

 	// Check no token appears twice
 	// We know it's sorted...
-	for i := 1; i < len(r.Entries); i++ {
-		if r.Entries[i-1].Token == r.Entries[i].Token {
+	for i := 1; i < len(entries); i++ {
+		if entries[i-1].Token == entries[i].Token {
 			return ErrTokenRepeated
 		}
 	}

-	if len(r.Entries) == 0 {
+	if len(entries) == 0 {
 		return nil
 	}

 	// Check tokens are in range
-	if r.Entries.entry(0).Token < r.Start {
+	if entries.entry(0).Token < r.Start {
 		return ErrTokenOutOfRange
 	}
-	if r.Entries.entry(-1).Token >= r.End {
+	if entries.entry(-1).Token >= r.End {
 		return ErrTokenOutOfRange
 	}

 	// Check all the freespaces are in range
-	for i, entry := range r.Entries {
-		next := r.Entries.entry(i + 1)
+	for i, entry := range entries {
+		next := entries.entry(i + 1)
 		distance := r.distance(entry.Token, next.Token)

 		if entry.Free > distance {
@@ -83,27 +97,47 @@ func (r *Ring) checkInvariants() error {
 	return nil
 }

+func (r *Ring) trackUpdates() func() {
+	return r.trackUpdatesOfPeer(r.Peer)
+}
+
+func (r *Ring) trackUpdatesOfPeer(peer mesh.PeerName) func() {
+	if r.onUpdate == nil {
+		return func() {}
+	}
+	ranges := r.OwnedRangesOfPeer(peer)
+	return func() { r.onUpdate(ranges, r.OwnedRangesOfPeer(peer), peer == r.Peer) }
+}
+
 // New creates an empty ring belonging to peer.
-func New(start, end address.Address, peer router.PeerName) *Ring {
+func New(start, end address.Address, peer mesh.PeerName, f OnUpdate) *Ring {
 	common.Assert(start < end)

-	ring := &Ring{Start: start, End: end, Peer: peer, Entries: make([]*entry, 0)}
+	ring := &Ring{Start: start, End: end, Peer: peer, Entries: make([]*entry, 0), onUpdate: f}
 	ring.updateExportedVariables()
 	return ring
 }

+func (r *Ring) Restore(other *Ring) {
+	defer r.trackUpdates()()
+
+	onUpdate := r.onUpdate
+	*r = *other
+	r.onUpdate = onUpdate
+}
+
 func (r *Ring) Range() address.Range {
 	return address.Range{Start: r.Start, End: r.End}
 }

 // Returns the distance between two tokens on this ring, dealing
 // with ranges which cross the origin
-func (r *Ring) distance(start, end address.Address) address.Offset {
+func (r *Ring) distance(start, end address.Address) address.Count {
 	if end > start {
-		return address.Offset(end - start)
+		return address.Count(end - start)
 	}

-	return address.Offset((r.End - start) + (end - r.Start))
+	return address.Count((r.End - start) + (end - r.Start))
 }

 // GrantRangeToHost modifies the ring such that range [start, end)
@@ -111,10 +145,11 @@ func (r *Ring) distance(start, end address.Address) address.Offset {
 // Preconditions:
 // - start < end
 // - [start, end) must be owned by the calling peer
-func (r *Ring) GrantRangeToHost(start, end address.Address, peer router.PeerName) {
+func (r *Ring) GrantRangeToHost(start, end address.Address, peer mesh.PeerName) {
 	//fmt.Printf("%s GrantRangeToHost [%v,%v) -> %s\n", r.Peer, start, end, peer)

 	r.assertInvariants()
+	defer r.trackUpdates()()
 	defer r.assertInvariants()
 	defer r.updateExportedVariables()

@@ -178,43 +213,70 @@ func (r *Ring) GrantRangeToHost(start, end address.Address, peer router.PeerName
 	r.Entries.insert(entry{Token: end, Peer: r.Peer, Free: endFree})
 }

-// Merge the given ring into this ring and return any new ranges added
-func (r *Ring) Merge(gossip Ring) error {
+// Merge the given ring into this ring and indicate whether this ring
+// got updated as a result.
+func (r *Ring) Merge(gossip Ring) (bool, error) {
 	r.assertInvariants()
-	defer r.assertInvariants()
+	defer r.trackUpdates()()
 	defer r.updateExportedVariables()

 	// Don't panic when checking the gossiped in ring.
 	// In this case just return any error found.
 	if err := gossip.checkInvariants(); err != nil {
-		return err
+		return false, err
 	}

 	if len(gossip.Seeds) > 0 && len(r.Seeds) > 0 {
 		if len(gossip.Seeds) != len(r.Seeds) {
-			return ErrDifferentSeeds
+			return false, ErrDifferentSeeds
 		}
 		for i, seed := range gossip.Seeds {
 			if seed != r.Seeds[i] {
-				return ErrDifferentSeeds
+				return false, ErrDifferentSeeds
 			}
 		}
 	}

 	if r.Start != gossip.Start || r.End != gossip.End {
-		return ErrDifferentRange
+		return false, ErrDifferentRange
 	}

-	// Now merge their ring with yours, in a temporary ring.
-	var result entries
-	addToResult := func(e entry) { result = append(result, &e) }
+	result, updated, err := r.Entries.merge(gossip.Entries, r.Peer)

+	if err != nil {
+		return false, err
+	}
+
+	if err := r.checkEntries(result); err != nil {
+		return false, fmt.Errorf("Merge of incoming data causes: %s", err)
+	}
+
+	if len(r.Seeds) == 0 {
+		r.Seeds = gossip.Seeds
+	}
+	r.Entries = result
+
+	return updated, nil
+}
+
+// Merge other entries into ours, and complain when that stomps on
+// entries belonging to ourPeer. Returns the merged entries and an
+// indication whether the merge resulted in any changes, i.e. the
+// result differs from the original.
+func (es entries) merge(other entries, ourPeer mesh.PeerName) (result entries, updated bool, err error) {
 	var mine, theirs *entry
-	var previousOwner *router.PeerName
-	// i is index into r.Entries; j is index into gossip.Entries
+	var previousOwner *mesh.PeerName
+	addToResult := func(e entry) { result = append(result, &e) }
+	addTheirs := func(e entry) {
+		addToResult(e)
+		updated = true
+		previousOwner = nil
+	}
+
+	// i is index into es; j is index into other
 	var i, j int
-	for i < len(r.Entries) && j < len(gossip.Entries) {
-		mine, theirs = r.Entries[i], gossip.Entries[j]
+	for i < len(es) && j < len(other) {
+		mine, theirs = es[i], other[j]
 		switch {
 		case mine.Token < theirs.Token:
 			addToResult(*mine)
@@ -222,56 +284,52 @@ func (r *Ring) Merge(gossip Ring) error {
 			i++
 		case mine.Token > theirs.Token:
 			// insert, checking that a range owned by us hasn't been split
-			if previousOwner != nil && *previousOwner == r.Peer && theirs.Peer != r.Peer {
-				return ErrEntryInMyRange
+			if previousOwner != nil && *previousOwner == ourPeer && theirs.Peer != ourPeer {
+				err = errEntryInMyRange(theirs)
+				return
 			}
-			addToResult(*theirs)
-			previousOwner = nil
+			addTheirs(*theirs)
 			j++
 		case mine.Token == theirs.Token:
 			// merge
 			switch {
 			case mine.Version >= theirs.Version:
 				if mine.Version == theirs.Version && !mine.Equal(theirs) {
-					common.Log.Debugf("Error merging entries at %s - %v != %v", mine.Token, mine, theirs)
-					return ErrInvalidEntry
+					err = errInconsistentEntry(mine, theirs)
+					return
 				}
 				addToResult(*mine)
 				previousOwner = &mine.Peer
 			case mine.Version < theirs.Version:
-				if mine.Peer == r.Peer { // We shouldn't receive updates to our own tokens
-					return ErrNewerVersion
+				if mine.Peer == ourPeer { // We shouldn't receive updates to our own tokens
+					err = errNewerVersion(mine, theirs)
+					return
 				}
-				addToResult(*theirs)
-				previousOwner = nil
+				addTheirs(*theirs)
 			}
 			i++
 			j++
 		}
 	}

-	// At this point, either i is at the end of r or j is at the end
-	// of gossip, so copy over the remaining entries.
+	// At this point, either i is at the end of es or j is at the end
+	// of other, so copy over the remaining entries.

-	for ; i < len(r.Entries); i++ {
-		mine = r.Entries[i]
+	for ; i < len(es); i++ {
+		mine = es[i]
 		addToResult(*mine)
 	}

-	for ; j < len(gossip.Entries); j++ {
-		theirs = gossip.Entries[j]
-		if previousOwner != nil && *previousOwner == r.Peer && theirs.Peer != r.Peer {
-			return ErrEntryInMyRange
+	for ; j < len(other); j++ {
+		theirs = other[j]
+		if previousOwner != nil && *previousOwner == ourPeer && theirs.Peer != ourPeer {
+			err = errEntryInMyRange(theirs)
+			return
 		}
-		addToResult(*theirs)
-		previousOwner = nil
+		addTheirs(*theirs)
 	}

-	if len(r.Seeds) == 0 {
-		r.Seeds = gossip.Seeds
-	}
-	r.Entries = result
-	return nil
+	return
 }

 // Empty returns true if the ring has no entries
@@ -304,10 +362,14 @@ func (r *Ring) splitRangesOverZero(ranges []address.Range) []address.Range {
 // ranges are owned by this peer.  Will split ranges which
 // span 0 in the ring.
 func (r *Ring) OwnedRanges() (result []address.Range) {
+	return r.OwnedRangesOfPeer(r.Peer)
+}
+
+func (r *Ring) OwnedRangesOfPeer(peer mesh.PeerName) (result []address.Range) {
 	r.assertInvariants()

 	for i, entry := range r.Entries {
-		if entry.Peer == r.Peer {
+		if entry.Peer == peer {
 			nextEntry := r.Entries.entry(i + 1)
 			result = append(result, address.Range{Start: entry.Token, End: nextEntry.Token})
 		}
@@ -316,41 +378,59 @@ func (r *Ring) OwnedRanges() (result []address.Range) {
 	return r.splitRangesOverZero(result)
 }

+// For printing status
+type RangeInfo struct {
+	Peer mesh.PeerName
+	address.Range
+	Version uint32
+}
+
+func (r *Ring) AllRangeInfo() (result []RangeInfo) {
+	for i, entry := range r.Entries {
+		nextEntry := r.Entries.entry(i + 1)
+		ranges := []address.Range{{Start: entry.Token, End: nextEntry.Token}}
+		ranges = r.splitRangesOverZero(ranges)
+		for _, r := range ranges {
+			result = append(result, RangeInfo{entry.Peer, r, entry.Version})
+		}
+	}
+	return
+}
+
 // ClaimForPeers claims the entire ring for the array of peers passed
-// in.  Only works for empty rings.
-func (r *Ring) ClaimForPeers(peers []router.PeerName) {
+// in.  Only works for empty rings. Each claimed range is CIDR-aligned.
+func (r *Ring) ClaimForPeers(peers []mesh.PeerName) {
 	common.Assert(r.Empty())
+
+	defer r.trackUpdates()()
 	defer r.assertInvariants()
 	defer r.updateExportedVariables()
+	defer func() {
+		e := r.Entries[len(r.Entries)-1]
+		common.Assert(address.Add(e.Token, address.Offset(e.Free)) == r.End)
+	}()

-	totalSize := r.distance(r.Start, r.End)
-	share := totalSize/address.Offset(len(peers)) + 1
-	remainder := totalSize % address.Offset(len(peers))
-	pos := r.Start
-
-	for i, peer := range peers {
-		if address.Offset(i) == remainder {
-			share--
-			if share == 0 {
-				break
-			}
-		}
-
-		if e, found := r.Entries.get(pos); found {
-			e.update(peer, share)
-		} else {
-			r.Entries.insert(entry{Token: pos, Peer: peer, Free: share})
-		}
-
-		pos += address.Address(share)
-	}
-
-	common.Assert(pos == r.End)
-
+	r.subdivide(r.Start, r.End, peers)
 	r.Seeds = peers
 }

-func (r *Ring) FprintWithNicknames(w io.Writer, m map[router.PeerName]string) {
+// subdivide subdivides the [from,to) CIDR for the given peers into
+// CIDR-aligned subranges.
+func (r *Ring) subdivide(from, to address.Address, peers []mesh.PeerName) {
+	share := address.Length(to, from)
+	if share == 0 {
+		return
+	}
+	if share == 1 || len(peers) == 1 {
+		r.Entries.insert(entry{Token: from, Peer: peers[0], Free: share})
+		return
+	}
+	mid := address.Add(from, address.Offset(share/2))
+	r.subdivide(from, mid, peers[:len(peers)/2])
+	r.subdivide(address.Add(mid, address.Offset(share%2)), to, peers[len(peers)/2:])
+}
+
+func (r *Ring) FprintWithNicknames(w io.Writer, m map[mesh.PeerName]string) {
 	for _, entry := range r.Entries {
 		nickname, found := m[entry.Peer]
 		if found {
@@ -365,14 +445,14 @@ func (r *Ring) FprintWithNicknames(w io.Writer, m map[router.PeerName]string) {
 func (r *Ring) String() string {
 	var buffer bytes.Buffer
 	fmt.Fprintf(&buffer, "Ring [%s, %s)", r.Start, r.End)
-	r.FprintWithNicknames(&buffer, make(map[router.PeerName]string))
+	r.FprintWithNicknames(&buffer, make(map[mesh.PeerName]string))
 	return buffer.String()
 }

 // ReportFree is used by the allocator to tell the ring how many free
 // ips are in a given range, so that ChoosePeersToAskForSpace can make
-// more intelligent decisions.
-func (r *Ring) ReportFree(freespace map[address.Address]address.Offset) {
+// more intelligent decisions.  Returns true if any changes made.
+func (r *Ring) ReportFree(freespace map[address.Address]address.Count) (updated bool) {
 	r.assertInvariants()
 	defer r.assertInvariants()
 	defer r.updateExportedVariables()
@@ -402,20 +482,22 @@ func (r *Ring) ReportFree(freespace map[address.Address]address.Offset) {
 		// Check we're not reporting more space than the range
 		entry, next := entries.entry(i), entries.entry(i+1)
 		maxSize := r.distance(entry.Token, next.Token)
-		common.Assert(free <= maxSize)
+		common.Assert(free <= address.Count(maxSize))

 		if entries[i].Free == free {
-			return
+			continue
 		}

 		entries[i].Free = free
 		entries[i].Version++
+		updated = true
 	}
+	return
 }

 type weightedPeer struct {
 	weight   float64
-	peername router.PeerName
+	peername mesh.PeerName
 }
 type weightedPeers []weightedPeer

@@ -426,11 +508,8 @@ func (ws weightedPeers) Swap(i, j int)      { ws[i], ws[j] = ws[j], ws[i] }

 // ChoosePeersToAskForSpace returns all peers we can ask for space in
 // the range [start, end), in weighted-random order.  Assumes start<end.
-func (r *Ring) ChoosePeersToAskForSpace(start, end address.Address) []router.PeerName {
-	var (
-		sum               address.Offset
-		totalSpacePerPeer = make(map[router.PeerName]address.Offset) // Compute total free space per peer
-	)
+func (r *Ring) ChoosePeersToAskForSpace(start, end address.Address) []mesh.PeerName {
+	totalSpacePerPeer := make(map[mesh.PeerName]address.Count)

 	// iterate through tokens
 	for i, entry := range r.Entries {
@@ -452,7 +531,6 @@ func (r *Ring) ChoosePeersToAskForSpace(start, end address.Address) []router.Pee
 		}

 		totalSpacePerPeer[entry.Peer] += entry.Free
-		sum += entry.Free
 	}

 	// Compute weighted random numbers, then sort.
@@ -463,46 +541,42 @@ func (r *Ring) ChoosePeersToAskForSpace(start, end address.Address) []router.Pee
 		ws = append(ws, weightedPeer{weight: float64(space) * rand.Float64(), peername: peername})
 	}
 	sort.Sort(ws)
-	result := make([]router.PeerName, len(ws))
+	result := make([]mesh.PeerName, len(ws))
 	for i, wp := range ws {
 		result[i] = wp.peername
 	}
 	return result
 }

-func (r *Ring) PickPeerForTransfer(isValid func(router.PeerName) bool) router.PeerName {
+func (r *Ring) PickPeerForTransfer(isValid func(mesh.PeerName) bool) mesh.PeerName {
 	for _, entry := range r.Entries {
 		if entry.Peer != r.Peer && isValid(entry.Peer) {
 			return entry.Peer
 		}
 	}
-	return router.UnknownPeerName
+	return mesh.UnknownPeerName
 }

 // Transfer will mark all entries associated with 'from' peer as owned by 'to' peer
 // and return ranges indicating the new space we picked up
-func (r *Ring) Transfer(from, to router.PeerName) ([]address.Range, error) {
+func (r *Ring) Transfer(from, to mesh.PeerName) []address.Range {
 	r.assertInvariants()
+	defer r.trackUpdates()()
+	defer r.trackUpdatesOfPeer(from)()
 	defer r.assertInvariants()
 	defer r.updateExportedVariables()

 	var newRanges []address.Range
-	found := false

 	for i, entry := range r.Entries {
 		if entry.Peer == from {
-			found = true
 			entry.Peer = to
 			entry.Version++
 			newRanges = append(newRanges, address.Range{Start: entry.Token, End: r.Entries.entry(i + 1).Token})
 		}
 	}

-	if !found {
-		return nil, ErrNotFound
-	}
-
-	return r.splitRangesOverZero(newRanges), nil
+	return r.splitRangesOverZero(newRanges)
 }

 // Contains returns true if addr is in this ring
@@ -511,13 +585,13 @@ func (r *Ring) Contains(addr address.Address) bool {
 }

 // Owner returns the peername which owns the range containing addr
-func (r *Ring) Owner(token address.Address) router.PeerName {
+func (r *Ring) Owner(token address.Address) mesh.PeerName {
 	common.Assert(r.Start <= token && token < r.End)

 	r.assertInvariants()
 	// There can be no owners on an empty ring
 	if r.Empty() {
-		return router.UnknownPeerName
+		return mesh.UnknownPeerName
 	}

 	// Look for the right-most entry, less than or equal to token
@@ -530,8 +604,8 @@ func (r *Ring) Owner(token address.Address) router.PeerName {
 }

 // Get the set of PeerNames mentioned in the ring
-func (r *Ring) PeerNames() map[router.PeerName]struct{} {
-	res := make(map[router.PeerName]struct{})
+func (r *Ring) PeerNames() map[mesh.PeerName]struct{} {
+	res := make(map[mesh.PeerName]struct{})

 	for _, entry := range r.Entries {
 		res[entry.Peer] = struct{}{}
@@ -8,17 +8,19 @@ import (
 	"testing"

 	"github.com/stretchr/testify/require"
+	"github.com/weaveworks/mesh"
+
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 var (
-	peer1name, _ = router.PeerNameFromString("01:00:00:00:02:00")
-	peer2name, _ = router.PeerNameFromString("02:00:00:00:02:00")
-	peer3name, _ = router.PeerNameFromString("03:00:00:00:02:00")
+	peer1name, _ = mesh.PeerNameFromString("01:00:00:00:02:00")
+	peer2name, _ = mesh.PeerNameFromString("02:00:00:00:02:00")
+	peer3name, _ = mesh.PeerNameFromString("03:00:00:00:02:00")

-	start, end    = ParseIP("10.0.0.0"), ParseIP("10.0.0.255")
+	start, end    = ParseIP("10.0.0.0"), ParseIP("10.0.1.0")
+	dot8          = ParseIP("10.0.0.8")
 	dot10, dot245 = ParseIP("10.0.0.10"), ParseIP("10.0.0.245")
 	dot250        = ParseIP("10.0.0.250")
 	middle        = ParseIP("10.0.0.128")
@@ -29,8 +31,17 @@ func ParseIP(s string) address.Address {
 	return addr
 }

+func merge(r1, r2 *Ring) error {
+	_, err := r1.Merge(*r2)
+	return err
+}
+
+func NewRing(start, end address.Address, peer mesh.PeerName) *Ring {
+	return New(start, end, peer, nil)
+}
+
 func TestInvariants(t *testing.T) {
-	ring := New(start, end, peer1name)
+	ring := NewRing(start, end, peer1name)

 	// Check ring is sorted
 	ring.Entries = []*entry{{Token: dot245, Peer: peer1name}, {Token: dot10, Peer: peer2name}}
@@ -41,7 +52,7 @@ func TestInvariants(t *testing.T) {
 	require.True(t, ring.checkInvariants() == ErrTokenRepeated, "Expected error")

 	// Check tokens are in bounds
-	ring = New(dot10, dot245, peer1name)
+	ring = NewRing(dot10, dot245, peer1name)
 	ring.Entries = []*entry{{Token: start, Peer: peer1name}}
 	require.True(t, ring.checkInvariants() == ErrTokenOutOfRange, "Expected error")

@@ -50,7 +61,7 @@ func TestInvariants(t *testing.T) {
 }

 func TestInsert(t *testing.T) {
-	ring := New(start, end, peer1name)
+	ring := NewRing(start, end, peer1name)
 	ring.Entries = []*entry{{Token: start, Peer: peer1name, Free: 255}}

 	require.Panics(t, func() {
@@ -59,17 +70,23 @@ func TestInsert(t *testing.T) {

 	ring.Entries.entry(0).Free = 0
 	ring.Entries.insert(entry{Token: dot245, Peer: peer1name})
-	ring2 := New(start, end, peer1name)
-	ring2.Entries = []*entry{{Token: start, Peer: peer1name, Free: 0}, {Token: dot245, Peer: peer1name}}
-	require.Equal(t, ring2, ring)
+	check := []RangeInfo{
+		{Peer: peer1name, Range: address.Range{Start: start, End: dot245}},
+		{Peer: peer1name, Range: address.Range{Start: dot245, End: end}},
+	}
+	require.Equal(t, check, ring.AllRangeInfo())

 	ring.Entries.insert(entry{Token: dot10, Peer: peer1name})
-	ring2.Entries = []*entry{{Token: start, Peer: peer1name, Free: 0}, {Token: dot10, Peer: peer1name}, {Token: dot245, Peer: peer1name}}
-	require.Equal(t, ring2, ring)
+	check2 := []RangeInfo{
+		{Peer: peer1name, Range: address.Range{Start: start, End: dot10}},
+		{Peer: peer1name, Range: address.Range{Start: dot10, End: dot245}},
+		{Peer: peer1name, Range: address.Range{Start: dot245, End: end}},
+	}
+	require.Equal(t, check2, ring.AllRangeInfo())
 }

 func TestBetween(t *testing.T) {
-	ring1 := New(start, end, peer1name)
+	ring1 := NewRing(start, end, peer1name)
 	ring1.Entries = []*entry{{Token: start, Peer: peer1name, Free: 255}}

 	// First off, in a ring where everything is owned by the peer
@@ -111,29 +128,29 @@ func TestBetween(t *testing.T) {
 }

 func TestGrantSimple(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	// Claim everything for peer1
 	ring1.ClaimItAll()
-	require.Equal(t, entries{{Token: start, Peer: peer1name, Free: 255}}, ring1.Entries)
+	require.Equal(t, entries{{Token: start, Peer: peer1name, Free: 256}}, ring1.Entries)

 	// Now grant everything to peer2
 	ring1.GrantRangeToHost(start, end, peer2name)
-	ring2.Entries = []*entry{{Token: start, Peer: peer2name, Free: 255, Version: 1}}
+	ring2.Entries = []*entry{{Token: start, Peer: peer2name, Free: 256, Version: 1}}
 	require.Equal(t, ring2.Entries, ring1.Entries)

 	// Now spint back to peer 1
 	ring2.GrantRangeToHost(dot10, end, peer1name)
 	ring1.Entries = []*entry{{Token: start, Peer: peer2name, Free: 10, Version: 2},
-		{Token: dot10, Peer: peer1name, Free: 245}}
+		{Token: dot10, Peer: peer1name, Free: 246}}
 	require.Equal(t, ring2.Entries, ring1.Entries)

 	// And spint back to peer 2 again
 	ring1.GrantRangeToHost(dot245, end, peer2name)
 	require.Equal(t, entries{{Token: start, Peer: peer2name, Free: 10, Version: 2},
 		{Token: dot10, Peer: peer1name, Free: 235, Version: 1},
-		{Token: dot245, Peer: peer2name, Free: 10}}, ring1.Entries)
+		{Token: dot245, Peer: peer2name, Free: 11}}, ring1.Entries)

 	// Grant range spanning a live token
 	ring1.Entries = []*entry{{Token: start, Peer: peer1name, Free: 10, Version: 2},
@@ -146,19 +163,19 @@ func TestGrantSimple(t *testing.T) {
 }

 func TestGrantSplit(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	// Claim everything for peer1
-	ring1.Entries = []*entry{{Token: start, Peer: peer1name, Free: 255}}
-	ring2.Merge(*ring1)
+	ring1.Entries = []*entry{{Token: start, Peer: peer1name, Free: 256}}
+	merge(ring2, ring1)
 	require.Equal(t, ring2.Entries, ring1.Entries)

 	// Now grant a split range to peer2
 	ring1.GrantRangeToHost(dot10, dot245, peer2name)
 	require.Equal(t, entries{{Token: start, Peer: peer1name, Free: 10, Version: 1},
 		{Token: dot10, Peer: peer2name, Free: 235},
-		{Token: dot245, Peer: peer1name, Free: 10}}, ring1.Entries)
+		{Token: dot245, Peer: peer1name, Free: 11}}, ring1.Entries)

 	ring1.assertInvariants()

@@ -169,22 +186,22 @@ func TestGrantSplit(t *testing.T) {
 	require.Equal(t, entries{{Token: start, Peer: peer1name, Free: 10, Version: 2},
 		{Token: dot10, Peer: peer2name, Free: 118, Version: 1},
 		{Token: middle, Peer: peer2name, Free: 117, Version: 1},
-		{Token: dot245, Peer: peer1name, Free: 10, Version: 0}}, ring1.Entries)
+		{Token: dot245, Peer: peer1name, Free: 11, Version: 0}}, ring1.Entries)

 	ring1.assertInvariants()
 }

 func TestMergeSimple(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	// Claim everything for peer1
 	ring1.ClaimItAll()
 	ring1.GrantRangeToHost(middle, end, peer2name)
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))

 	require.Equal(t, entries{{Token: start, Peer: peer1name, Free: 128, Version: 1},
-		{Token: middle, Peer: peer2name, Free: 127}}, ring1.Entries)
+		{Token: middle, Peer: peer2name, Free: 128}}, ring1.Entries)

 	require.Equal(t, ring2.Entries, ring1.Entries)

@@ -193,47 +210,48 @@ func TestMergeSimple(t *testing.T) {
 	ring1.GrantRangeToHost(start, middle, peer2name)
 	ring2.GrantRangeToHost(middle, end, peer1name)

-	require.NoError(t, ring2.Merge(*ring1))
-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring2, ring1))
+	require.NoError(t, merge(ring1, ring2))

 	require.Equal(t, entries{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127, Version: 1}}, ring1.Entries)
+		{Token: middle, Peer: peer1name, Free: 128, Version: 1}}, ring1.Entries)

 	require.Equal(t, ring2.Entries, ring1.Entries)
 }

 func TestMergeErrors(t *testing.T) {
 	// Cannot Merge in an invalid ring
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)
 	ring2.Entries = []*entry{{Token: middle, Peer: peer2name}, {Token: start, Peer: peer2name}}
-	require.True(t, ring1.Merge(*ring2) == ErrNotSorted, "Expected ErrNotSorted")
+	require.True(t, merge(ring1, ring2) == ErrNotSorted, "Expected ErrNotSorted")

 	// Should Merge two rings for different ranges
-	ring2 = New(start, middle, peer2name)
+	ring2 = NewRing(start, middle, peer2name)
 	ring2.Entries = []*entry{}
-	require.True(t, ring1.Merge(*ring2) == ErrDifferentRange, "Expected ErrDifferentRange")
+	require.True(t, merge(ring1, ring2) == ErrDifferentRange, "Expected ErrDifferentRange")

 	// Cannot Merge newer version of entry I own
-	ring2 = New(start, end, peer2name)
+	ring2 = NewRing(start, end, peer2name)
 	ring1.Entries = []*entry{{Token: start, Peer: peer1name}}
 	ring2.Entries = []*entry{{Token: start, Peer: peer1name, Version: 1}}
-	require.True(t, ring1.Merge(*ring2) == ErrNewerVersion, "Expected ErrNewerVersion")
+	fmt.Println(merge(ring1, ring2))
+	require.Error(t, merge(ring1, ring2), "Expected error")

 	// Cannot Merge two entries with same version but different hosts
 	ring1.Entries = []*entry{{Token: start, Peer: peer1name}}
 	ring2.Entries = []*entry{{Token: start, Peer: peer2name}}
-	require.True(t, ring1.Merge(*ring2) == ErrInvalidEntry, "Expected ErrInvalidEntry")
+	require.Error(t, merge(ring1, ring2), "Expected error")

 	// Cannot Merge an entry into a range I own
 	ring1.Entries = []*entry{{Token: start, Peer: peer1name}}
 	ring2.Entries = []*entry{{Token: middle, Peer: peer2name}}
-	require.True(t, ring1.Merge(*ring2) == ErrEntryInMyRange, "Expected ErrEntryInMyRange")
+	require.Error(t, merge(ring1, ring2), "Expected error")
 }

 func TestMergeMore(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	assertRing := func(ring *Ring, entries entries) {
 		require.Equal(t, entries, ring.Entries)
@@ -244,74 +262,74 @@ func TestMergeMore(t *testing.T) {

 	// Claim everything for peer1
 	ring1.ClaimItAll()
-	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 255}})
+	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 256}})
 	assertRing(ring2, []*entry{})

 	// Check the Merge sends it to the other ring
-	require.NoError(t, ring2.Merge(*ring1))
-	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 255}})
-	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 255}})
+	require.NoError(t, merge(ring2, ring1))
+	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 256}})
+	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 256}})

 	// Give everything to peer2
 	ring1.GrantRangeToHost(start, end, peer2name)
-	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 255, Version: 1}})
-	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 255}})
+	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 256, Version: 1}})
+	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 256}})

-	require.NoError(t, ring2.Merge(*ring1))
-	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 255, Version: 1}})
-	assertRing(ring2, []*entry{{Token: start, Peer: peer2name, Free: 255, Version: 1}})
+	require.NoError(t, merge(ring2, ring1))
+	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 256, Version: 1}})
+	assertRing(ring2, []*entry{{Token: start, Peer: peer2name, Free: 256, Version: 1}})

 	// And carve off some space
 	ring2.GrantRangeToHost(middle, end, peer1name)
 	assertRing(ring2, []*entry{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127}})
-	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 255, Version: 1}})
+		{Token: middle, Peer: peer1name, Free: 128}})
+	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 256, Version: 1}})

 	// And Merge back
-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring1, ring2))
 	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127}})
+		{Token: middle, Peer: peer1name, Free: 128}})
 	assertRing(ring2, []*entry{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127}})
+		{Token: middle, Peer: peer1name, Free: 128}})

 	// This should be a no-op
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))
 	assertRing(ring1, []*entry{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127}})
+		{Token: middle, Peer: peer1name, Free: 128}})
 	assertRing(ring2, []*entry{{Token: start, Peer: peer2name, Free: 128, Version: 2},
-		{Token: middle, Peer: peer1name, Free: 127}})
+		{Token: middle, Peer: peer1name, Free: 128}})
 }

 func TestMergeSplit(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	// Claim everything for peer2
-	ring1.Entries = []*entry{{Token: start, Peer: peer2name, Free: 255}}
-	require.NoError(t, ring2.Merge(*ring1))
+	ring1.Entries = []*entry{{Token: start, Peer: peer2name, Free: 256}}
+	require.NoError(t, merge(ring2, ring1))
 	require.Equal(t, ring2.Entries, ring1.Entries)

 	// Now grant a split range to peer1
 	ring2.GrantRangeToHost(dot10, dot245, peer1name)
 	require.Equal(t, entries{{Token: start, Peer: peer2name, Free: 10, Version: 1},
 		{Token: dot10, Peer: peer1name, Free: 235},
-		{Token: dot245, Peer: peer2name, Free: 10}}, ring2.Entries)
+		{Token: dot245, Peer: peer2name, Free: 11}}, ring2.Entries)

-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring1, ring2))
 	require.Equal(t, entries{{Token: start, Peer: peer2name, Free: 10, Version: 1},
 		{Token: dot10, Peer: peer1name, Free: 235},
-		{Token: dot245, Peer: peer2name, Free: 10}}, ring1.Entries)
+		{Token: dot245, Peer: peer2name, Free: 11}}, ring1.Entries)

 	require.Equal(t, ring2.Entries, ring1.Entries)
 }

 func TestMergeSplit2(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	// Claim everything for peer2
 	ring1.Entries = []*entry{{Token: start, Peer: peer2name, Free: 250}, {Token: dot250, Peer: peer2name, Free: 5}}
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))
 	require.Equal(t, ring2.Entries, ring1.Entries)

 	// Now grant a split range to peer1
@@ -320,7 +338,7 @@ func TestMergeSplit2(t *testing.T) {
 		{Token: dot10, Peer: peer1name, Free: 235},
 		{Token: dot245, Peer: peer2name, Free: 5}, {Token: dot250, Peer: peer2name, Free: 5}}, ring2.Entries)

-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring1, ring2))
 	require.Equal(t, entries{{Token: start, Peer: peer2name, Free: 10, Version: 1},
 		{Token: dot10, Peer: peer1name, Free: 235},
 		{Token: dot245, Peer: peer2name, Free: 5}, {Token: dot250, Peer: peer2name, Free: 5}}, ring1.Entries)
@@ -330,8 +348,8 @@ func TestMergeSplit2(t *testing.T) {

 // A simple test, very similar to above, but using the marshalling to byte[]s
 func TestGossip(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	assertRing := func(ring *Ring, entries entries) {
 		require.Equal(t, entries, ring.Entries)
@@ -342,23 +360,23 @@ func TestGossip(t *testing.T) {

 	// Claim everything for peer1
 	ring1.ClaimItAll()
-	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 255}})
+	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 256}})
 	assertRing(ring2, []*entry{})

 	// Check the Merge sends it to the other ring
-	require.NoError(t, ring2.Merge(*ring1))
-	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 255}})
-	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 255}})
+	require.NoError(t, merge(ring2, ring1))
+	assertRing(ring1, []*entry{{Token: start, Peer: peer1name, Free: 256}})
+	assertRing(ring2, []*entry{{Token: start, Peer: peer1name, Free: 256}})
 }

-func assertPeersWithSpace(t *testing.T, ring *Ring, start, end address.Address, expected int) []router.PeerName {
+func assertPeersWithSpace(t *testing.T, ring *Ring, start, end address.Address, expected int) []mesh.PeerName {
 	peers := ring.ChoosePeersToAskForSpace(start, end)
 	require.Equal(t, expected, len(peers))
 	return peers
 }

 func TestFindFree(t *testing.T) {
-	ring1 := New(start, end, peer1name)
+	ring1 := NewRing(start, end, peer1name)

 	assertPeersWithSpace(t, ring1, start, end, 0)

@@ -366,7 +384,7 @@ func TestFindFree(t *testing.T) {
 	assertPeersWithSpace(t, ring1, start, end, 0)

 	// We shouldn't return outselves
-	ring1.ReportFree(map[address.Address]address.Offset{start: 10})
+	ring1.ReportFree(map[address.Address]address.Count{start: 10})
 	assertPeersWithSpace(t, ring1, start, end, 0)

 	ring1.Entries = []*entry{{Token: start, Peer: peer1name, Free: 1},
@@ -375,7 +393,7 @@ func TestFindFree(t *testing.T) {
 	ring1.assertInvariants()

 	// We should return others
-	var peers []router.PeerName
+	var peers []mesh.PeerName

 	ring1.Entries = []*entry{{Token: start, Peer: peer2name, Free: 1}}
 	peers = assertPeersWithSpace(t, ring1, start, end, 1)
@@ -394,14 +412,14 @@ func TestFindFree(t *testing.T) {
 }

 func TestReportFree(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	ring1.ClaimItAll()
 	ring1.GrantRangeToHost(middle, end, peer2name)
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))

-	freespace := make(map[address.Address]address.Offset)
+	freespace := make(map[address.Address]address.Count)
 	for _, r := range ring2.OwnedRanges() {
 		freespace[r.Start] = 0
 	}
@@ -409,7 +427,7 @@ func TestReportFree(t *testing.T) {
 }

 func TestMisc(t *testing.T) {
-	ring := New(start, end, peer1name)
+	ring := NewRing(start, end, peer1name)

 	require.True(t, ring.Empty(), "empty")

@@ -418,38 +436,38 @@ func TestMisc(t *testing.T) {
 }

 func TestEmptyGossip(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	ring1.ClaimItAll()
 	// This used to panic, and it shouldn't
-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring1, ring2))
 }

 func TestMergeOldMessage(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	ring1.ClaimItAll()
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))

 	ring1.GrantRangeToHost(middle, end, peer1name)
-	require.NoError(t, ring1.Merge(*ring2))
+	require.NoError(t, merge(ring1, ring2))
 }

 func TestSplitRangeAtBeginning(t *testing.T) {
-	ring1 := New(start, end, peer1name)
-	ring2 := New(start, end, peer2name)
+	ring1 := NewRing(start, end, peer1name)
+	ring2 := NewRing(start, end, peer2name)

 	ring1.ClaimItAll()
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))

 	ring1.GrantRangeToHost(start, middle, peer2name)
-	require.NoError(t, ring2.Merge(*ring1))
+	require.NoError(t, merge(ring2, ring1))
 }

 func TestOwnedRange(t *testing.T) {
-	ring1 := New(start, end, peer1name)
+	ring1 := NewRing(start, end, peer1name)
 	ring1.ClaimItAll()

 	require.Equal(t, []address.Range{{Start: start, End: end}}, ring1.OwnedRanges())
@@ -457,8 +475,8 @@ func TestOwnedRange(t *testing.T) {
 	ring1.GrantRangeToHost(middle, end, peer2name)
 	require.Equal(t, []address.Range{{Start: start, End: middle}}, ring1.OwnedRanges())

-	ring2 := New(start, end, peer2name)
-	ring2.Merge(*ring1)
+	ring2 := NewRing(start, end, peer2name)
+	merge(ring2, ring1)
 	require.Equal(t, []address.Range{{Start: middle, End: end}}, ring2.OwnedRanges())

 	ring2.Entries = []*entry{{Token: middle, Peer: peer2name}}
@@ -472,7 +490,7 @@ func TestOwnedRange(t *testing.T) {

 func TestTransfer(t *testing.T) {
 	// First test just checks if we can grant some range to a host, when we transfer it, we get it back
-	ring1 := New(start, end, peer1name)
+	ring1 := NewRing(start, end, peer1name)
 	ring1.ClaimItAll()
 	ring1.GrantRangeToHost(middle, end, peer2name)
 	ring1.Transfer(peer2name, peer1name)
@@ -480,7 +498,7 @@ func TestTransfer(t *testing.T) {

 	// Second test is what happens when a token exists at the end of a range but is transferred
 	// - does it get resurrected correctly?
-	ring1 = New(start, end, peer1name)
+	ring1 = NewRing(start, end, peer1name)
 	ring1.ClaimItAll()
 	ring1.GrantRangeToHost(middle, end, peer2name)
 	ring1.Transfer(peer2name, peer1name)
@@ -489,11 +507,11 @@ func TestTransfer(t *testing.T) {
 }

 func TestOwner(t *testing.T) {
-	ring1 := New(start, end, peer1name)
+	ring1 := NewRing(start, end, peer1name)
 	require.True(t, ring1.Contains(start), "start should be in ring")
 	require.False(t, ring1.Contains(end), "end should not be in ring")

-	require.Equal(t, router.UnknownPeerName, ring1.Owner(start))
+	require.Equal(t, mesh.UnknownPeerName, ring1.Owner(start))

 	ring1.ClaimItAll()
 	ring1.GrantRangeToHost(middle, end, peer2name)
@@ -505,6 +523,36 @@ func TestOwner(t *testing.T) {

 }

+func makePeerName(i int) mesh.PeerName {
+	if i >= 10000 {
+		panic("makePeerName: invalid value")
+	}
+	peer, _ := mesh.PeerNameFromString(fmt.Sprintf("%02d:%02d:00:00:00:ff", i/100, i%100))
+	return peer
+}
+
+func makePeers(numPeers int) []mesh.PeerName {
+	peers := make([]mesh.PeerName, numPeers)
+	for i := 0; i < numPeers; i++ {
+		peers[i] = makePeerName(i)
+	}
+	return peers
+}
+
+func TestClaimForPeers(t *testing.T) {
+	const numPeers = 12
+	// Different end to usual so we get a number of addresses that a)
+	// is smaller than the max number of peers, and b) is divisible by
+	// some number of peers. This maximises coverage of edge cases.
+	end := dot8
+	peers := makePeers(numPeers)
+	// Test for a range of peer counts
+	for i := 0; i < numPeers; i++ {
+		ring := NewRing(start, end, peers[0])
+		ring.ClaimForPeers(peers[:i+1])
+	}
+}
+
 type addressSlice []address.Address

 func (s addressSlice) Len() int           { return len(s) }
@@ -517,10 +565,9 @@ func TestFuzzRing(t *testing.T) {
 		iterations = 1000
 	)

-	peers := make([]router.PeerName, numPeers)
+	peers := make([]mesh.PeerName, numPeers)
 	for i := 0; i < numPeers; i++ {
-		peer, _ := router.PeerNameFromString(fmt.Sprintf("%02d:00:00:00:02:00", i))
-		peers[i] = peer
+		peers[i] = makePeerName(i)
 	}

 	// Make a valid, random ring
@@ -539,7 +586,7 @@ func TestFuzzRing(t *testing.T) {
 		sort.Sort(addressSlice(tokens))

 		peer := peers[rand.Intn(len(peers))]
-		ring := New(start, end, peer)
+		ring := NewRing(start, end, peer)
 		for _, token := range tokens {
 			peer = peers[rand.Intn(len(peers))]
 			ring.Entries = append(ring.Entries, &entry{Token: start + token, Peer: peer})
@@ -556,7 +603,7 @@ func TestFuzzRing(t *testing.T) {

 		// Merge them - this might fail, we don't care
 		// We just want to make sure it doesn't panic
-		ring1.Merge(*ring2)
+		merge(ring1, ring2)

 		// Check whats left still passes assertions
 		ring1.assertInvariants()
@@ -573,7 +620,7 @@ func TestFuzzRing(t *testing.T) {
 		}

 		peer := peers[rand.Intn(len(peers))]
-		ring := New(start, end, peer)
+		ring := NewRing(start, end, peer)
 		for _, token := range tokens {
 			peer = peers[rand.Intn(len(peers))]
 			ring.Entries = append(ring.Entries, &entry{Token: start + token, Peer: peer})
@@ -589,7 +636,7 @@ func TestFuzzRing(t *testing.T) {

 		// Merge them - this might fail, we don't care
 		// We just want to make sure it doesn't panic
-		ring1.Merge(*ring2)
+		merge(ring1, ring2)

 		// Check whats left still passes assertions
 		ring1.assertInvariants()
@@ -601,17 +648,17 @@ func TestFuzzRingHard(t *testing.T) {
 	var (
 		numPeers   = 100
 		iterations = 3000
-		peers      []router.PeerName
+		peers      []mesh.PeerName
 		rings      []*Ring
 		nextPeerID = 0
 	)

 	addPeer := func() {
-		peer, _ := router.PeerNameFromString(fmt.Sprintf("%02d:%02d:00:00:00:00", nextPeerID/10, nextPeerID%10))
+		peer := makePeerName(nextPeerID)
 		common.Log.Debugf("%s: Adding peer", peer)
 		nextPeerID++
 		peers = append(peers, peer)
-		rings = append(rings, New(start, end, peer))
+		rings = append(rings, NewRing(start, end, peer))
 	}

 	for i := 0; i < numPeers; i++ {
@@ -620,7 +667,7 @@ func TestFuzzRingHard(t *testing.T) {

 	rings[0].ClaimItAll()

-	randomPeer := func(exclude int) (int, router.PeerName, *Ring) {
+	randomPeer := func(exclude int) (int, mesh.PeerName, *Ring) {
 		var peerIndex int
 		if exclude >= 0 {
 			peerIndex = rand.Intn(len(peers) - 1)
@@ -650,7 +697,7 @@ func TestFuzzRingHard(t *testing.T) {

 		// We need to be in a ~converged ring to rmpeer
 		for _, ring := range rings {
-			require.NoError(t, otherRing.Merge(*ring))
+			require.NoError(t, merge(otherRing, ring))
 		}

 		common.Log.Debugf("%s: transferring from peer %s", otherPeername, peername)
@@ -664,7 +711,7 @@ func TestFuzzRingHard(t *testing.T) {
 		// And now tell everyone about the transfer - rmpeer is
 		// not partition safe
 		for i, ring := range rings {
-			require.NoError(t, ring.Merge(*otherRing))
+			require.NoError(t, merge(ring, otherRing))
 			theRanges[i] = ring.OwnedRanges()
 		}
 	}
@@ -693,7 +740,7 @@ func TestFuzzRingHard(t *testing.T) {
 			// Now 'gossip' this to a random host (note, note could be same host as above)
 			otherIndex, _, otherRing := randomPeer(-1)
 			common.Log.Debugf("%s: 'Gossiping' to %s", ring.Peer, otherRing.Peer)
-			require.NoError(t, otherRing.Merge(*ring))
+			require.NoError(t, merge(otherRing, ring))

 			theRanges[indexWithRanges] = ring.OwnedRanges()
 			theRanges[otherIndex] = otherRing.OwnedRanges()
@@ -712,7 +759,7 @@ func TestFuzzRingHard(t *testing.T) {
 		ring1 := ringsWithEntries[rand.Intn(len(ringsWithEntries))]
 		ring2index, _, ring2 := randomPeer(-1)
 		common.Log.Debugf("%s: 'Gossiping' to %s", ring1.Peer, ring2.Peer)
-		require.NoError(t, ring2.Merge(*ring1))
+		require.NoError(t, merge(ring2, ring1))
 		theRanges[ring2index] = ring2.OwnedRanges()
 	}

@@ -729,7 +776,7 @@ func TestFuzzRingHard(t *testing.T) {
 }

 func (r *Ring) ClaimItAll() {
-	r.ClaimForPeers([]router.PeerName{r.Peer})
+	r.ClaimForPeers([]mesh.PeerName{r.Peer})
 }

 func (es entries) String() string {
@@ -31,8 +31,8 @@ func (s *Space) Add(start address.Address, size address.Offset) {

 // Clear removes all spaces from this space set.  Used during node shutdown.
 func (s *Space) Clear() {
-	s.free = s.free[:0]
 	s.ours = s.ours[:0]
+	s.free = s.free[:0]
 }

 // Walk down the free list calling f() on the in-range portions, until
@@ -88,8 +88,16 @@ func (s *Space) Claim(addr address.Address) error {
 	return nil
 }

-func (s *Space) NumFreeAddressesInRange(r address.Range) address.Offset {
-	res := address.Offset(0)
+func (s *Space) NumFreeAddresses() address.Count {
+	res := address.Count(0)
+	for i := 0; i < len(s.free); i += 2 {
+		res += address.Length(s.free[i+1], s.free[i])
+	}
+	return res
+}
+
+func (s *Space) NumFreeAddressesInRange(r address.Range) address.Count {
+	res := address.Count(0)
 	s.walkFree(r, func(chunk address.Range) bool {
 		res += chunk.Size()
 		return false
@@ -111,11 +119,14 @@ func (s *Space) Free(addr address.Address) error {
 }

 func (s *Space) biggestFreeRange(r address.Range) (biggest address.Range) {
-	biggestSize := address.Offset(0)
+	biggestSize := address.Count(0)
 	s.walkFree(r, func(chunk address.Range) bool {
 		if size := chunk.Size(); size >= biggestSize {
-			biggest = chunk
-			biggestSize = size
+			chunk = chunk.BiggestCIDRRange()
+			if size = chunk.Size(); size >= biggestSize {
+				biggest = chunk
+				biggestSize = size
+			}
 		}
 		return false
 	})
@@ -129,9 +140,12 @@ func (s *Space) Donate(r address.Range) (address.Range, bool) {
 		return address.Range{}, false
 	}

-	// Donate half of that biggest free range. Note size/2 rounds down, so
-	// the resulting donation size rounds up, and in particular can't be empty.
-	biggest.Start = address.Add(biggest.Start, biggest.Size()/2)
+	// Donate no more than half what we have available
+	if biggest.Size() > s.NumFreeAddressesInRange(r)/2 {
+		// Note size/2 rounds down, so the resulting donation size
+		// rounds up, and in particular can't be empty.
+		biggest.Start = address.Add(biggest.Start, address.Offset(biggest.Size()/2))
+	}

 	s.ours = subtract(s.ours, biggest.Start, biggest.End)
 	s.free = subtract(s.free, biggest.Start, biggest.End)
@@ -19,16 +19,6 @@ func ip(s string) address.Address {
 	return addr
 }

-// Helper function to avoid 'NumFreeAddressesInRange(start, end)'
-// dozens of times in tests
-func (s *Space) NumFreeAddresses() address.Offset {
-	res := address.Offset(0)
-	for i := 0; i < len(s.free); i += 2 {
-		res += address.Subtract(s.free[i+1], s.free[i])
-	}
-	return res
-}
-
 func TestLowlevel(t *testing.T) {
 	a := []address.Address{}
 	a = add(a, 100, 200)
@@ -61,24 +51,24 @@ func TestLowlevel(t *testing.T) {
 	require.Equal(t, []address.Address{}, a)

 	s := New()
-	require.Equal(t, address.Offset(0), s.NumFreeAddresses())
+	require.Equal(t, address.Count(0), s.NumFreeAddresses())
 	ok, got := s.Allocate(address.NewRange(0, 1000))
 	require.False(t, ok, "allocate in empty space should fail")

 	s.Add(100, 100)
-	require.Equal(t, address.Offset(100), s.NumFreeAddresses())
+	require.Equal(t, address.Count(100), s.NumFreeAddresses())
 	ok, got = s.Allocate(address.NewRange(0, 1000))
 	require.True(t, ok && got == 100, "allocate")
-	require.Equal(t, address.Offset(99), s.NumFreeAddresses())
+	require.Equal(t, address.Count(99), s.NumFreeAddresses())
 	require.NoError(t, s.Claim(150))
-	require.Equal(t, address.Offset(98), s.NumFreeAddresses())
+	require.Equal(t, address.Count(98), s.NumFreeAddresses())
 	require.NoError(t, s.Free(100))
-	require.Equal(t, address.Offset(99), s.NumFreeAddresses())
+	require.Equal(t, address.Count(99), s.NumFreeAddresses())
 	wt.AssertErrorInterface(t, (*error)(nil), s.Free(0), "free not allocated")
 	wt.AssertErrorInterface(t, (*error)(nil), s.Free(100), "double free")

 	r, ok := s.Donate(address.NewRange(0, 1000))
-	require.True(t, ok && r.Start == 125 && r.Size() == 25, "donate")
+	require.Equal(t, address.NewRange(0xa0, 0x20), r, "donate")

 	// test Donate when addresses are scarce
 	s = New()
@@ -88,7 +78,7 @@ func TestLowlevel(t *testing.T) {
 	require.NoError(t, s.Claim(0))
 	require.NoError(t, s.Claim(2))
 	r, ok = s.Donate(address.NewRange(0, 1000))
-	require.True(t, ok && r.Start == 1 && r.End == 2, "donate")
+	require.Equal(t, address.NewRange(1, 1), r, "donate")
 	r, ok = s.Donate(address.NewRange(0, 1000))
 	require.True(t, !ok, "donate should fail")
 }
@@ -107,19 +97,19 @@ func TestSpaceAllocate(t *testing.T) {
 	)

 	space1 := makeSpace(start, size)
-	require.Equal(t, address.Offset(20), space1.NumFreeAddresses())
+	require.Equal(t, address.Count(20), space1.NumFreeAddresses())
 	space1.assertInvariants()

 	_, addr1 := space1.Allocate(address.NewRange(start, size))
 	require.Equal(t, testAddr1, addr1.String(), "address")
-	require.Equal(t, address.Offset(19), space1.NumFreeAddresses())
+	require.Equal(t, address.Count(19), space1.NumFreeAddresses())
 	space1.assertInvariants()

 	_, addr2 := space1.Allocate(address.NewRange(start, size))
 	require.False(t, addr2.String() == testAddr1, "address")
-	require.Equal(t, address.Offset(18), space1.NumFreeAddresses())
-	require.Equal(t, address.Offset(13), space1.NumFreeAddressesInRange(address.Range{Start: ip(testAddr1), End: ip(testAddrx)}))
-	require.Equal(t, address.Offset(18), space1.NumFreeAddressesInRange(address.Range{Start: ip(testAddr1), End: ip(testAddry)}))
+	require.Equal(t, address.Count(18), space1.NumFreeAddresses())
+	require.Equal(t, address.Count(13), space1.NumFreeAddressesInRange(address.Range{Start: ip(testAddr1), End: ip(testAddrx)}))
+	require.Equal(t, address.Count(18), space1.NumFreeAddressesInRange(address.Range{Start: ip(testAddr1), End: ip(testAddry)}))
 	space1.assertInvariants()

 	space1.Free(addr2)
@@ -134,20 +124,21 @@ func TestSpaceAllocate(t *testing.T) {

 func TestSpaceFree(t *testing.T) {
 	const (
-		testAddr1   = "10.0.3.4"
+		testAddr1   = "10.0.3.16"
 		testAddrx   = "10.0.3.19"
 		testAddry   = "10.0.9.19"
 		containerID = "deadbeef"
+		size        = 16
 	)

-	entireRange := address.NewRange(ip(testAddr1), 20)
-	space := makeSpace(ip(testAddr1), 20)
+	entireRange := address.NewRange(ip(testAddr1), size)
+	space := makeSpace(ip(testAddr1), size)

 	// Check we are prepared to give up the entire space
 	r := space.biggestFreeRange(entireRange)
-	require.True(t, r.Start == ip(testAddr1) && r.Size() == 20, "Wrong space")
+	require.Equal(t, address.NewRange(ip(testAddr1), size), r, "Wrong space")

-	for i := 0; i < 20; i++ {
+	for i := 0; i < size; i++ {
 		ok, _ := space.Allocate(entireRange)
 		require.True(t, ok, "Failed to get address")
 	}
@@ -155,48 +146,48 @@ func TestSpaceFree(t *testing.T) {
 	// Check we are full
 	ok, _ := space.Allocate(entireRange)
 	require.True(t, !ok, "Should have failed to get address")
-	r, ok = space.Donate(entireRange)
+	r, _ = space.Donate(entireRange)
 	require.True(t, r.Size() == 0, "Wrong space")

 	// Free in the middle
-	require.NoError(t, space.Free(ip("10.0.3.13")))
-	r = space.biggestFreeRange(entireRange)
-	require.True(t, r.Start == ip("10.0.3.13") && r.Size() == 1, "Wrong space")
-
-	// Free one at the end
 	require.NoError(t, space.Free(ip("10.0.3.23")))
 	r = space.biggestFreeRange(entireRange)
 	require.True(t, r.Start == ip("10.0.3.23") && r.Size() == 1, "Wrong space")

+	// Free one at the end
+	require.NoError(t, space.Free(ip("10.0.3.31")))
+	r = space.biggestFreeRange(entireRange)
+	require.True(t, r.Start == ip("10.0.3.31") && r.Size() == 1, "Wrong space")
+
 	// Now free a few at the end
+	require.NoError(t, space.Free(ip("10.0.3.30")))
+	require.NoError(t, space.Free(ip("10.0.3.29")))
+
+	require.Equal(t, address.Count(4), space.NumFreeAddresses())
+
+	// Now get the biggest free space; should be 3.30
+	r = space.biggestFreeRange(entireRange)
+	require.Equal(t, address.NewRange(ip("10.0.3.30"), 2), r, "Wrong space")
+
+	// Now free a few in the middle
+	require.NoError(t, space.Free(ip("10.0.3.24")))
 	require.NoError(t, space.Free(ip("10.0.3.22")))
 	require.NoError(t, space.Free(ip("10.0.3.21")))

-	require.Equal(t, address.Offset(4), space.NumFreeAddresses())
+	require.Equal(t, address.Count(7), space.NumFreeAddresses())

-	// Now get the biggest free space; should be 3.21
+	// Now get the biggest free space; should be 3.30
 	r = space.biggestFreeRange(entireRange)
-	require.True(t, r.Start == ip("10.0.3.21") && r.Size() == 3, "Wrong space")
+	require.Equal(t, address.NewRange(ip("10.0.3.30"), 2), r, "Wrong space")

-	// Now free a few in the middle
-	require.NoError(t, space.Free(ip("10.0.3.12")))
-	require.NoError(t, space.Free(ip("10.0.3.11")))
-	require.NoError(t, space.Free(ip("10.0.3.10")))
-
-	require.Equal(t, address.Offset(7), space.NumFreeAddresses())
-
-	// Now get the biggest free space; should be 3.21
-	r = space.biggestFreeRange(entireRange)
-	require.True(t, r.Start == ip("10.0.3.10") && r.Size() == 4, "Wrong space")
-
-	require.Equal(t, []address.Range{{Start: ip("10.0.3.4"), End: ip("10.0.3.24")}}, space.OwnedRanges())
+	require.Equal(t, []address.Range{{Start: ip("10.0.3.16"), End: ip("10.0.3.32")}}, space.OwnedRanges())
 }

 func TestDonateSimple(t *testing.T) {
 	const (
 		testAddr1 = "10.0.1.0"
 		testAddr2 = "10.0.1.32"
-		size      = 48
+		size      = 64
 	)

 	var (
@@ -209,9 +200,9 @@ func TestDonateSimple(t *testing.T) {
 	r, ok := ps1.Donate(address.NewRange(ip(testAddr1), size))
 	numGivenUp := r.Size()
 	require.True(t, ok, "Donate result")
-	require.Equal(t, "10.0.1.24", r.Start.String(), "Invalid start")
-	require.Equal(t, address.Offset(size/2), numGivenUp)
-	require.Equal(t, address.Offset(size/2), ps1.NumFreeAddresses())
+	require.Equal(t, "10.0.1.32", r.Start.String(), "Invalid start")
+	require.Equal(t, address.Count(size/2), numGivenUp)
+	require.Equal(t, address.Count(size/2), ps1.NumFreeAddresses())

 	// Now check we can give the rest up.
 	count := 0 // count to avoid infinite loop
@@ -222,8 +213,8 @@ func TestDonateSimple(t *testing.T) {
 		}
 		numGivenUp += r.Size()
 	}
-	require.Equal(t, address.Offset(0), ps1.NumFreeAddresses())
-	require.Equal(t, address.Offset(size), numGivenUp)
+	require.Equal(t, address.Count(0), ps1.NumFreeAddresses())
+	require.Equal(t, address.Count(size), numGivenUp)
 }

 func TestDonateHard(t *testing.T) {
@@ -240,7 +231,7 @@ func TestDonateHard(t *testing.T) {
 		require.True(t, ok, "Failed to get IP!")
 	}

-	require.Equal(t, address.Offset(0), spaceset.NumFreeAddresses())
+	require.Equal(t, address.Count(0), spaceset.NumFreeAddresses())

 	// Now free all but the last address
 	// this will force us to split the free list
@@ -251,13 +242,13 @@ func TestDonateHard(t *testing.T) {
 	// Now split
 	newRange, ok := spaceset.Donate(address.NewRange(start, size))
 	require.True(t, ok, "GiveUpSpace result")
-	require.Equal(t, ip("10.0.1.23"), newRange.Start)
-	require.Equal(t, address.Offset(24), newRange.Size())
-	require.Equal(t, address.Offset(23), spaceset.NumFreeAddresses())
+	require.Equal(t, address.NewRange(ip("10.0.1.16"), 16), newRange, "Wrong space")
+	require.Equal(t, address.Count(31), spaceset.NumFreeAddresses())

-	//Space set should now have 2 spaces
-	expected := New()
-	expected.Add(start, 23)
-	expected.ours = add(nil, ip("10.0.1.47"), ip("10.0.1.48"))
+	//Space set should now have 3 spaces
+	expected := &Space{
+		ours: add(nil, ip("10.0.1.47"), ip("10.0.1.48")),
+		free: add(add(nil, ip("10.0.1.0"), ip("10.0.1.16")), ip("10.0.1.32"), ip("10.0.1.47")),
+	}
 	require.Equal(t, expected, spaceset)
 }
@@ -1,6 +1,7 @@
 package ipam

 import (
+	"fmt"
 	"github.com/weaveworks/weave/ipam/paxos"
 	"github.com/weaveworks/weave/net/address"
 )
@@ -8,6 +9,7 @@ import (
 type Status struct {
 	Paxos            *paxos.Status
 	Range            string
+	RangeNumIPs      int
 	DefaultSubnet    string
 	Entries          []EntryStatus
 	PendingClaims    []ClaimStatus
@@ -15,14 +17,17 @@ type Status struct {
 }

 type EntryStatus struct {
-	Token   string
-	Peer    string
-	Version uint32
+	Token       string
+	Size        uint32
+	Peer        string
+	Nickname    string
+	IsKnownPeer bool
+	Version     uint32
 }

 type ClaimStatus struct {
-	Ident   string
-	Address address.Address
+	Ident string
+	CIDR  address.CIDR
 }

 func NewStatus(allocator *Allocator, defaultSubnet address.CIDR) *Status {
@@ -31,8 +36,14 @@ func NewStatus(allocator *Allocator, defaultSubnet address.CIDR) *Status {
 	}

 	var paxosStatus *paxos.Status
-	if allocator.paxosTicker != nil {
-		paxosStatus = paxos.NewStatus(allocator.paxos)
+	if allocator.awaitingConsensus && allocator.paxos != nil {
+		if allocator.paxos.IsElector() {
+			if node, ok := allocator.paxos.(*paxos.Node); ok {
+				paxosStatus = paxos.NewStatus(node)
+			}
+		} else {
+			paxosStatus = &paxos.Status{Elector: false}
+		}
 	}

 	resultChan := make(chan *Status)
@@ -40,6 +51,7 @@ func NewStatus(allocator *Allocator, defaultSubnet address.CIDR) *Status {
 		resultChan <- &Status{
 			paxosStatus,
 			allocator.universe.String(),
+			int(allocator.universe.Size()),
 			defaultSubnet.String(),
 			newEntryStatusSlice(allocator),
 			newClaimStatusSlice(allocator),
@@ -56,8 +68,15 @@ func newEntryStatusSlice(allocator *Allocator) []EntryStatus {
 		return slice
 	}

-	for _, entry := range allocator.ring.Entries {
-		slice = append(slice, EntryStatus{entry.Token.String(), entry.Peer.String(), entry.Version})
+	for _, r := range allocator.ring.AllRangeInfo() {
+		slice = append(slice, EntryStatus{
+			Token:       r.Start.String(),
+			Size:        uint32(r.Size()),
+			Peer:        r.Peer.String(),
+			Nickname:    allocator.nicknames[r.Peer],
+			IsKnownPeer: allocator.isKnownPeer(r.Peer),
+			Version:     r.Version,
+		})
 	}

 	return slice
@@ -67,7 +86,7 @@ func newClaimStatusSlice(allocator *Allocator) []ClaimStatus {
 	var slice []ClaimStatus
 	for _, op := range allocator.pendingClaims {
 		claim := op.(*claim)
-		slice = append(slice, ClaimStatus{claim.ident, claim.addr})
+		slice = append(slice, ClaimStatus{claim.ident, claim.cidr})
 	}
 	return slice
 }
@@ -76,7 +95,7 @@ func newAllocateIdentSlice(allocator *Allocator) []string {
 	var slice []string
 	for _, op := range allocator.pendingAllocates {
 		allocate := op.(*allocate)
-		slice = append(slice, allocate.ident)
+		slice = append(slice, fmt.Sprintf("%s %s", allocate.ident, allocate.r.String()))
 	}
 	return slice
 }
@@ -7,14 +7,15 @@ import (
 	"testing"
 	"time"

+	"github.com/weaveworks/mesh"
+
 	"github.com/stretchr/testify/require"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 	"github.com/weaveworks/weave/testing/gossip"
 )

 type mockMessage struct {
-	dst     router.PeerName
+	dst     mesh.PeerName
 	msgType byte
 	buf     []byte
 }
@@ -48,13 +49,13 @@ func (m *mockGossipComms) String() string {
 // that the contents of messages are never re-ordered.  Which, for instance,
 // requires they are not based off iterating through a map.

-func (m *mockGossipComms) GossipBroadcast(update router.GossipData) error {
+func (m *mockGossipComms) GossipBroadcast(update mesh.GossipData) {
 	m.Lock()
 	defer m.Unlock()
 	buf := []byte{}
 	if len(m.messages) == 0 {
 		require.FailNow(m, fmt.Sprintf("%s: Gossip broadcast message unexpected: \n%x", m.name, buf))
-	} else if msg := m.messages[0]; msg.dst != router.UnknownPeerName {
+	} else if msg := m.messages[0]; msg.dst != mesh.UnknownPeerName {
 		require.FailNow(m, fmt.Sprintf("%s: Expected Gossip message to %s but got broadcast", m.name, msg.dst))
 	} else if msg.buf != nil && !equalByteBuffer(msg.buf, buf) {
 		require.FailNow(m, fmt.Sprintf("%s: Gossip message not sent as expected: \nwant: %x\ngot : %x", m.name, msg.buf, buf))
@@ -62,7 +63,6 @@ func (m *mockGossipComms) GossipBroadcast(update router.GossipData) error {
 		// Swallow this message
 		m.messages = m.messages[1:]
 	}
-	return nil
 }

 func equalByteBuffer(a, b []byte) bool {
@@ -77,12 +77,12 @@ func equalByteBuffer(a, b []byte) bool {
 	return true
 }

-func (m *mockGossipComms) GossipUnicast(dstPeerName router.PeerName, buf []byte) error {
+func (m *mockGossipComms) GossipUnicast(dstPeerName mesh.PeerName, buf []byte) error {
 	m.Lock()
 	defer m.Unlock()
 	if len(m.messages) == 0 {
 		require.FailNow(m, fmt.Sprintf("%s: Gossip message to %s unexpected: \n%s", m.name, dstPeerName, buf))
-	} else if msg := m.messages[0]; msg.dst == router.UnknownPeerName {
+	} else if msg := m.messages[0]; msg.dst == mesh.UnknownPeerName {
 		require.FailNow(m, fmt.Sprintf("%s: Expected Gossip broadcast message but got dest %s", m.name, dstPeerName))
 	} else if msg.dst != dstPeerName {
 		require.FailNow(m, fmt.Sprintf("%s: Expected Gossip message to %s but got dest %s", m.name, msg.dst, dstPeerName))
@@ -99,7 +99,7 @@ func (m *mockGossipComms) GossipUnicast(dstPeerName router.PeerName, buf []byte)

 func ExpectMessage(alloc *Allocator, dst string, msgType byte, buf []byte) {
 	m := alloc.gossip.(*mockGossipComms)
-	dstPeerName, _ := router.PeerNameFromString(dst)
+	dstPeerName, _ := mesh.PeerNameFromString(dst)
 	m.Lock()
 	m.messages = append(m.messages, mockMessage{dstPeerName, msgType, buf})
 	m.Unlock()
@@ -108,7 +108,7 @@ func ExpectMessage(alloc *Allocator, dst string, msgType byte, buf []byte) {
 func ExpectBroadcastMessage(alloc *Allocator, buf []byte) {
 	m := alloc.gossip.(*mockGossipComms)
 	m.Lock()
-	m.messages = append(m.messages, mockMessage{router.UnknownPeerName, 0, buf})
+	m.messages = append(m.messages, mockMessage{mesh.UnknownPeerName, 0, buf})
 	m.Unlock()
 }

@@ -123,24 +123,35 @@ func CheckAllExpectedMessagesSent(allocs ...*Allocator) {
 	}
 }

-func makeAllocator(name string, cidrStr string, quorum uint) (*Allocator, address.Range) {
-	peername, err := router.PeerNameFromString(name)
+type mockDB struct{}
+
+func (d *mockDB) Load(_ string, _ interface{}) (bool, error) { return false, nil }
+func (d *mockDB) Save(_ string, _ interface{}) error         { return nil }
+
+func makeAllocator(name string, cidrStr string, quorum uint) (*Allocator, address.CIDR) {
+	peername, err := mesh.PeerNameFromString(name)
 	if err != nil {
 		panic(err)
 	}

-	_, cidr, err := address.ParseCIDR(cidrStr)
+	cidr, err := address.ParseCIDR(cidrStr)
 	if err != nil {
 		panic(err)
 	}

-	alloc := NewAllocator(peername, router.PeerUID(rand.Int63()),
-		"nick-"+name, cidr.Range(), quorum, func(router.PeerName) bool { return true })
-
-	return alloc, cidr.HostRange()
+	return NewAllocator(Config{
+		OurName:     peername,
+		OurUID:      mesh.PeerUID(rand.Int63()),
+		OurNickname: "nick-" + name,
+		Universe:    cidr,
+		IsObserver:  quorum == 0,
+		Quorum:      func() uint { return quorum },
+		Db:          new(mockDB),
+		IsKnownPeer: func(mesh.PeerName) bool { return true },
+	}), cidr
 }

-func makeAllocatorWithMockGossip(t *testing.T, name string, universeCIDR string, quorum uint) (*Allocator, address.Range) {
+func makeAllocatorWithMockGossip(t *testing.T, name string, universeCIDR string, quorum uint) (*Allocator, address.CIDR) {
 	alloc, subnet := makeAllocator(name, universeCIDR, quorum)
 	gossip := &mockGossipComms{T: t, name: name}
 	alloc.SetInterfaces(gossip)
@@ -149,7 +160,7 @@ func makeAllocatorWithMockGossip(t *testing.T, name string, universeCIDR string,
 }

 func (alloc *Allocator) claimRingForTesting(allocs ...*Allocator) {
-	peers := []router.PeerName{alloc.ourName}
+	peers := []mesh.PeerName{alloc.ourName}
 	for _, alloc2 := range allocs {
 		peers = append(peers, alloc2.ourName)
 	}
@@ -157,14 +168,22 @@ func (alloc *Allocator) claimRingForTesting(allocs ...*Allocator) {
 	alloc.space.AddRanges(alloc.ring.OwnedRanges())
 }

-func (alloc *Allocator) NumFreeAddresses(r address.Range) address.Offset {
-	resultChan := make(chan address.Offset)
+func (alloc *Allocator) NumFreeAddresses(r address.Range) address.Count {
+	resultChan := make(chan address.Count)
 	alloc.actionChan <- func() {
 		resultChan <- alloc.space.NumFreeAddressesInRange(r)
 	}
 	return <-resultChan
 }

+func (alloc *Allocator) OwnedRanges() (result []address.Range) {
+	resultChan := make(chan []address.Range)
+	alloc.actionChan <- func() {
+		resultChan <- alloc.ring.OwnedRanges()
+	}
+	return <-resultChan
+}
+
 // Check whether or not something was sent on a channel
 func AssertSent(t *testing.T, ch <-chan bool) {
 	timeout := time.After(10 * time.Second)
@@ -194,10 +213,10 @@ func AssertNothingSentErr(t *testing.T, ch <-chan error) {
 	}
 }

-func makeNetworkOfAllocators(size int, cidr string) ([]*Allocator, *gossip.TestRouter, address.Range) {
+func makeNetworkOfAllocators(size int, cidr string) ([]*Allocator, *gossip.TestRouter, address.CIDR) {
 	gossipRouter := gossip.NewTestRouter(0.0)
 	allocs := make([]*Allocator, size)
-	var subnet address.Range
+	var subnet address.CIDR

 	for i := 0; i < size; i++ {
 		var alloc *Allocator
@@ -213,7 +232,10 @@ func makeNetworkOfAllocators(size int, cidr string) ([]*Allocator, *gossip.TestR
 	return allocs, gossipRouter, subnet
 }

-func stopNetworkOfAllocators(allocs []*Allocator) {
+func stopNetworkOfAllocators(allocs []*Allocator, gossipRouter *gossip.TestRouter) {
+	// NB: We must stop the router first since ipam gossip makes
+	// synchronous calls into the allocator.
+	gossipRouter.Stop()
 	for _, alloc := range allocs {
 		alloc.Stop()
 	}
@@ -0,0 +1,285 @@
+package tracker
+
+// The AWSVPC tracker tracks the IPAM ring changes and accordingly updates
+// the AWS VPC route table and, if the announced change is local
+// (denoted by local=true) to the host, the host route table.
+//
+// During the initialization, the tracker detects AWS VPC route table id which
+// is associated with the host's subnet on the AWS network. If such a table does
+// not exist, the default VPC route table is used.
+//
+// When a host A donates a range to a host B, the necessary route table
+// updates (removal) happen on the host A first, and afterwards on
+// the host B (installation).
+//
+// NB: there is a hard limit for 50 routes within any VPC route table
+// (practically, it is 48, because one route is used by the AWS Internet GW and
+// one by the AWS host subnet), therefore it is suggested to avoid
+// an excessive fragmentation within the IPAM ring which might happen due to
+// the claim operations or uneven distribution of containers across the hosts.
+
+import (
+	"fmt"
+	"net"
+	"syscall"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/ec2metadata"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/vishvananda/netlink"
+
+	"github.com/weaveworks/weave/common"
+	wnet "github.com/weaveworks/weave/net"
+	"github.com/weaveworks/weave/net/address"
+)
+
+type AWSVPCTracker struct {
+	ec2          *ec2.EC2
+	instanceID   string // EC2 Instance ID
+	routeTableID string // VPC Route Table ID
+	linkIndex    int    // The weave bridge link index
+}
+
+// NewAWSVPCTracker creates and initialises AWS VPC based tracker.
+func NewAWSVPCTracker() (*AWSVPCTracker, error) {
+	var (
+		err     error
+		session = session.New()
+		t       = &AWSVPCTracker{}
+	)
+
+	// Detect region and instance id
+	meta := ec2metadata.New(session)
+	t.instanceID, err = meta.GetMetadata("instance-id")
+	if err != nil {
+		return nil, fmt.Errorf("cannot detect instance-id: %s", err)
+	}
+	region, err := meta.Region()
+	if err != nil {
+		return nil, fmt.Errorf("cannot detect region: %s", err)
+	}
+
+	t.ec2 = ec2.New(session, aws.NewConfig().WithRegion(region))
+
+	routeTableID, err := t.detectRouteTableID()
+	if err != nil {
+		return nil, err
+	}
+	t.routeTableID = *routeTableID
+
+	// Detect Weave bridge link index
+	link, err := netlink.LinkByName(wnet.WeaveBridgeName)
+	if err != nil {
+		return nil, fmt.Errorf("cannot find \"%s\" interface: %s", wnet.WeaveBridgeName, err)
+	}
+	t.linkIndex = link.Attrs().Index
+
+	t.infof("AWSVPC has been initialized on %s instance for %s route table at %s region",
+		t.instanceID, t.routeTableID, region)
+
+	return t, nil
+}
+
+// HandleUpdate method updates the AWS VPC and the host route tables.
+func (t *AWSVPCTracker) HandleUpdate(prevRanges, currRanges []address.Range, local bool) error {
+	t.debugf("replacing %q by %q; local(%t)", prevRanges, currRanges, local)
+
+	prev, curr := removeCommon(address.NewCIDRs(merge(prevRanges)), address.NewCIDRs(merge(currRanges)))
+
+	// It might make sense to do the removal first and then add entries
+	// because of the 50 routes limit. However, in such case a container might
+	// not be reachable for a short period of time which is not a desired behavior.
+
+	// Add new entries
+	for _, cidr := range curr {
+		cidrStr := cidr.String()
+		t.debugf("adding route %s to %s", cidrStr, t.instanceID)
+		if _, err := t.createVPCRoute(cidrStr); err != nil {
+			return fmt.Errorf("createVPCRoutes failed: %s", err)
+		}
+		if local {
+			if err := t.createHostRoute(cidrStr); err != nil {
+				if errno, ok := err.(syscall.Errno); !(ok && errno == syscall.EEXIST) {
+					return fmt.Errorf("createHostRoute failed: %s", err)
+				}
+			}
+		}
+	}
+
+	// Remove obsolete entries
+	for _, cidr := range prev {
+		cidrStr := cidr.String()
+		t.debugf("removing %s route", cidrStr)
+		if _, err := t.deleteVPCRoute(cidrStr); err != nil {
+			return fmt.Errorf("deleteVPCRoute failed: %s", err)
+		}
+		if local {
+			if err := t.deleteHostRoute(cidrStr); err != nil {
+				return fmt.Errorf("deleteHostRoute failed: %s", err)
+			}
+		}
+	}
+
+	return nil
+}
+
+func (t *AWSVPCTracker) createVPCRoute(cidr string) (*ec2.CreateRouteOutput, error) {
+	route := &ec2.CreateRouteInput{
+		RouteTableId:         &t.routeTableID,
+		InstanceId:           &t.instanceID,
+		DestinationCidrBlock: &cidr,
+	}
+	return t.ec2.CreateRoute(route)
+}
+
+func (t *AWSVPCTracker) createHostRoute(cidr string) error {
+	dst, err := parseCIDR(cidr)
+	if err != nil {
+		return err
+	}
+	route := &netlink.Route{
+		LinkIndex: t.linkIndex,
+		Dst:       dst,
+		Scope:     netlink.SCOPE_LINK,
+	}
+	return netlink.RouteAdd(route)
+}
+
+func (t *AWSVPCTracker) deleteVPCRoute(cidr string) (*ec2.DeleteRouteOutput, error) {
+	route := &ec2.DeleteRouteInput{
+		RouteTableId:         &t.routeTableID,
+		DestinationCidrBlock: &cidr,
+	}
+	return t.ec2.DeleteRoute(route)
+}
+
+func (t *AWSVPCTracker) deleteHostRoute(cidr string) error {
+	dst, err := parseCIDR(cidr)
+	if err != nil {
+		return err
+	}
+	route := &netlink.Route{
+		LinkIndex: t.linkIndex,
+		Dst:       dst,
+		Scope:     netlink.SCOPE_LINK,
+	}
+	return netlink.RouteDel(route)
+}
+
+// detectRouteTableID detects AWS VPC Route Table ID of the given tracker instance.
+func (t *AWSVPCTracker) detectRouteTableID() (*string, error) {
+	instancesParams := &ec2.DescribeInstancesInput{
+		InstanceIds: []*string{aws.String(t.instanceID)},
+	}
+	instancesResp, err := t.ec2.DescribeInstances(instancesParams)
+	if err != nil {
+		return nil, fmt.Errorf("DescribeInstances failed: %s", err)
+	}
+	if len(instancesResp.Reservations) == 0 ||
+		len(instancesResp.Reservations[0].Instances) == 0 {
+		return nil, fmt.Errorf("cannot find %s instance within reservations", t.instanceID)
+	}
+	vpcID := instancesResp.Reservations[0].Instances[0].VpcId
+	subnetID := instancesResp.Reservations[0].Instances[0].SubnetId
+
+	// First try to find a routing table associated with the subnet of the instance
+	tablesParams := &ec2.DescribeRouteTablesInput{
+		Filters: []*ec2.Filter{
+			{
+				Name:   aws.String("association.subnet-id"),
+				Values: []*string{subnetID},
+			},
+		},
+	}
+	tablesResp, err := t.ec2.DescribeRouteTables(tablesParams)
+	if err != nil {
+		return nil, fmt.Errorf("DescribeRouteTables failed: %s", err)
+	}
+	if len(tablesResp.RouteTables) != 0 {
+		return tablesResp.RouteTables[0].RouteTableId, nil
+	}
+	// Fallback to the default routing table
+	tablesParams = &ec2.DescribeRouteTablesInput{
+		Filters: []*ec2.Filter{
+			{
+				Name:   aws.String("association.main"),
+				Values: []*string{aws.String("true")},
+			},
+			{
+				Name:   aws.String("vpc-id"),
+				Values: []*string{vpcID},
+			},
+		},
+	}
+	tablesResp, err = t.ec2.DescribeRouteTables(tablesParams)
+	if err != nil {
+		return nil, fmt.Errorf("DescribeRouteTables failed: %s", err)
+	}
+	if len(tablesResp.RouteTables) != 0 {
+		return tablesResp.RouteTables[0].RouteTableId, nil
+	}
+
+	return nil, fmt.Errorf("cannot find routetable for %s instance", t.instanceID)
+}
+
+func (t *AWSVPCTracker) debugf(fmt string, args ...interface{}) {
+	common.Log.Debugf("[tracker] "+fmt, args...)
+}
+
+func (t *AWSVPCTracker) infof(fmt string, args ...interface{}) {
+	common.Log.Infof("[tracker] "+fmt, args...)
+}
+
+// Helpers
+
+// merge merges adjacent range entries.
+// The given slice has to be sorted in increasing order.
+func merge(r []address.Range) []address.Range {
+	var merged []address.Range
+
+	for i := range r {
+		if prev := len(merged) - 1; prev >= 0 && merged[prev].End == r[i].Start {
+			merged[prev].End = r[i].End
+		} else {
+			merged = append(merged, r[i])
+		}
+	}
+
+	return merged
+}
+
+// removeCommon filters out CIDR ranges which are contained in both a and b slices.
+// Both slices have to be sorted in increasing order.
+func removeCommon(a, b []address.CIDR) (newA, newB []address.CIDR) {
+	i, j := 0, 0
+
+	for i < len(a) && j < len(b) {
+		switch {
+		case a[i].Start() < b[j].Start() || a[i].End() < b[j].End():
+			newA = append(newA, a[i])
+			i++
+		case a[i].Start() > b[j].Start() || a[i].End() > b[j].End():
+			newB = append(newB, b[j])
+			j++
+		default:
+			i++
+			j++
+		}
+
+	}
+	newA = append(newA, a[i:]...)
+	newB = append(newB, b[j:]...)
+
+	return
+}
+
+func parseCIDR(cidr string) (*net.IPNet, error) {
+	ip, ipnet, err := net.ParseCIDR(cidr)
+	if err != nil {
+		return nil, err
+	}
+	ipnet.IP = ip
+
+	return ipnet, nil
+}
@@ -0,0 +1,52 @@
+package tracker
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/weaveworks/weave/net/address"
+)
+
+var (
+	r0to127     = cidr("10.0.0.0", "10.0.0.127")
+	r128to255   = cidr("10.0.0.128", "10.0.0.255")
+	r0to255     = cidr("10.0.0.0", "10.0.0.255")
+	r1dot0to255 = cidr("10.0.1.0", "10.0.1.255")
+	r2dot0to255 = cidr("10.0.2.0", "10.0.2.255")
+)
+
+func TestRemoveCommon(t *testing.T) {
+	a := []address.CIDR{r0to127, r1dot0to255}
+	b := []address.CIDR{r1dot0to255, r2dot0to255}
+	newA, newB := removeCommon(a, b)
+	require.Equal(t, []address.CIDR{r0to127}, newA)
+	require.Equal(t, []address.CIDR{r2dot0to255}, newB)
+}
+
+func TestMerge(t *testing.T) {
+	ranges := []address.Range{
+		r0to127.Range(),
+		r128to255.Range(),
+		r2dot0to255.Range(),
+	}
+	require.Equal(t, []address.Range{r0to255.Range(), r2dot0to255.Range()}, merge(ranges))
+}
+
+// Helper
+
+// TODO(mp) DRY with helpers of other tests.
+
+func ip(s string) address.Address {
+	addr, _ := address.ParseIP(s)
+	return addr
+}
+
+// [start; end]
+func cidr(start, end string) address.CIDR {
+	c := address.Range{Start: ip(start), End: ip(end) + 1}.CIDRs()
+	if len(c) != 1 {
+		panic("invalid cidr")
+	}
+	return c[0]
+}
@@ -0,0 +1,20 @@
+package tracker
+
+import (
+	"github.com/weaveworks/weave/net/address"
+)
+
+// LocalRangeTracker is an interface for tracking changes in the IPAM ring.
+type LocalRangeTracker interface {
+	// HandleUpdate is called whenever an address ring gets updated.
+	//
+	// prevRanges corresponds to ranges which were owned by a peer before
+	// a change in the ring, while currRanges to the ones which are currently
+	// owned by the peer.
+	// Both slices have to be sorted in increasing order.
+	// Adjacent ranges within each slice might appear as separate ranges.
+	//
+	// The local parameter indicates whether the ranges belong to the peer
+	// by which the method is called.
+	HandleUpdate(prevRanges, currRanges []address.Range, local bool) error
+}
@@ -5,8 +5,10 @@ import (
 	"fmt"
 	"math/rand"
 	"net"
+	"os"
 	"sort"
 	"strings"
+	"sync"
 	"time"

 	"github.com/miekg/dns"
@@ -17,7 +19,6 @@ import (
 const (
 	topDomain        = "."
 	reverseDNSdomain = "in-addr.arpa."
-	etcResolvConf    = "/etc/resolv.conf"
 	udpBuffSize      = uint16(4096)
 	minUDPSize       = 512

@@ -26,16 +27,48 @@ const (
 	DefaultClientTimeout = 5 * time.Second
 )

-type DNSServer struct {
-	ns      *Nameserver
-	domain  string
-	ttl     uint32
-	address string
+type Upstream interface {
+	Config() *dns.ClientConfig
+}

-	servers   []*dns.Server
-	upstream  *dns.ClientConfig
-	tcpClient *dns.Client
-	udpClient *dns.Client
+func NewUpstream(resolvConf, filterAddress string) Upstream {
+	return &upstream{
+		resolvConf:    resolvConf,
+		filterAddress: filterAddress,
+		cachedConfig:  &dns.ClientConfig{}}
+}
+
+type upstream struct {
+	sync.Mutex
+
+	resolvConf    string
+	filterAddress string
+	cachedConfig  *dns.ClientConfig
+	lastStat      time.Time
+	lastModified  time.Time
+}
+
+func (u *upstream) Config() *dns.ClientConfig {
+	u.Lock()
+	defer u.Unlock()
+
+	// If we checked less than five seconds ago return what we already have
+	now := time.Now()
+	if now.Sub(u.lastStat) < 5*time.Second {
+		return u.cachedConfig
+	}
+	u.lastStat = now
+
+	// Reread file if it has changed
+	if fi, err := os.Stat(u.resolvConf); err == nil && fi.ModTime() != u.lastModified {
+		if config, err := dns.ClientConfigFromFile(u.resolvConf); err == nil {
+			config.Servers = filter(config.Servers, u.filterAddress)
+			u.lastModified = fi.ModTime()
+			u.cachedConfig = config
+		}
+	}
+
+	return u.cachedConfig
 }

 func filter(ss []string, s string) []string {
@@ -49,24 +82,30 @@ func filter(ss []string, s string) []string {
 	return ss
 }

-func NewDNSServer(ns *Nameserver, domain, address, effectiveAddress string, ttl uint32, clientTimeout time.Duration) (*DNSServer, error) {
+type DNSServer struct {
+	ns      *Nameserver
+	domain  string
+	ttl     uint32
+	address string
+
+	servers   []*dns.Server
+	upstream  Upstream
+	tcpClient *dns.Client
+	udpClient *dns.Client
+}
+
+func NewDNSServer(ns *Nameserver, domain, address string, upstream Upstream, ttl uint32, clientTimeout time.Duration) (*DNSServer, error) {
 	s := &DNSServer{
 		ns:        ns,
 		domain:    dns.Fqdn(domain),
 		ttl:       ttl,
 		address:   address,
+		upstream:  upstream,
 		tcpClient: &dns.Client{Net: "tcp", ReadTimeout: clientTimeout},
 		udpClient: &dns.Client{Net: "udp", ReadTimeout: clientTimeout, UDPSize: udpBuffSize},
 	}
-	var err error
-	if s.upstream, err = dns.ClientConfigFromFile(etcResolvConf); err != nil {
-		return nil, err
-	}
-	if s.upstream != nil {
-		s.upstream.Servers = filter(s.upstream.Servers, effectiveAddress)
-	}

-	err = s.listen(address)
+	err := s.listen(address)
 	return s, err
 }

@@ -134,7 +173,7 @@ func (d *DNSServer) createMux(client *dns.Client, defaultMaxResponseSize int) *d

 func (h *handler) handleLocal(w dns.ResponseWriter, req *dns.Msg) {
 	h.ns.debugf("local request: %+v", *req)
-	if len(req.Question) != 1 || req.Question[0].Qtype != dns.TypeA {
+	if len(req.Question) != 1 {
 		h.nameError(w, req)
 		return
 	}
@@ -149,6 +188,12 @@ func (h *handler) handleLocal(w dns.ResponseWriter, req *dns.Msg) {
 		h.nameError(w, req)
 		return
 	}
+	// Per RFC4074, if we have an A but another type was requested,
+	// return 'no error' with empty answer section
+	if req.Question[0].Qtype != dns.TypeA {
+		h.respond(w, h.makeResponse(req, nil))
+		return
+	}

 	header := dns.RR_Header{
 		Name:   req.Question[0].Name,
@@ -204,7 +249,7 @@ func (h *handler) handleRecursive(w dns.ResponseWriter, req *dns.Msg) {
 	h.ns.debugf("recursive request: %+v", *req)

 	// Resolve unqualified names locally
-	if len(req.Question) == 1 && req.Question[0].Qtype == dns.TypeA {
+	if len(req.Question) == 1 {
 		hostname := dns.Fqdn(req.Question[0].Name)
 		if strings.Count(hostname, ".") == 1 {
 			h.handleLocal(w, req)
@@ -212,10 +257,11 @@ func (h *handler) handleRecursive(w dns.ResponseWriter, req *dns.Msg) {
 		}
 	}

-	for _, server := range h.upstream.Servers {
+	upstreamConfig := h.upstream.Config()
+	for _, server := range upstreamConfig.Servers {
 		reqCopy := req.Copy()
 		reqCopy.Id = dns.Id()
-		response, _, err := h.client.Exchange(reqCopy, fmt.Sprintf("%s:%s", server, h.upstream.Port))
+		response, _, err := h.client.Exchange(reqCopy, fmt.Sprintf("%s:%s", server, upstreamConfig.Port))
 		if (err != nil && err != dns.ErrTruncated) || response == nil {
 			h.ns.debugf("error trying %s: %v", server, err)
 			continue
@@ -11,21 +11,26 @@ import (
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/require"

+	"github.com/weaveworks/mesh"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

+type mockUpstream struct {
+	config *dns.ClientConfig
+}
+
+func (mu *mockUpstream) Config() *dns.ClientConfig {
+	return mu.config
+}
+
 func startServer(t *testing.T, upstream *dns.ClientConfig) (*DNSServer, *Nameserver, int, int) {
-	peername, err := router.PeerNameFromString("00:00:00:02:00:00")
+	peername, err := mesh.PeerNameFromString("00:00:00:02:00:00")
 	require.Nil(t, err)
-	nameserver := New(peername, nil, "")
-	dnsserver, err := NewDNSServer(nameserver, "weave.local.", "0.0.0.0:0", "", 30, 5*time.Second)
+	nameserver := New(peername, "", func(mesh.PeerName) bool { return true })
+	dnsserver, err := NewDNSServer(nameserver, "weave.local.", "0.0.0.0:0", &mockUpstream{upstream}, 30, 5*time.Second)
 	require.Nil(t, err)
 	udpPort := dnsserver.servers[0].PacketConn.LocalAddr().(*net.UDPAddr).Port
 	tcpPort := dnsserver.servers[1].Listener.Addr().(*net.TCPAddr).Port
-	if upstream != nil {
-		dnsserver.upstream = upstream
-	}
 	go dnsserver.ActivateAndServe()
 	return dnsserver, nameserver, udpPort, tcpPort
 }
@@ -39,7 +44,7 @@ func TestTruncation(t *testing.T) {
 	addrs := []address.Address{}
 	for i := address.Address(0); i < 100; i++ {
 		addrs = append(addrs, i)
-		nameserver.AddEntry("foo.weave.local.", "", router.UnknownPeerName, i)
+		nameserver.AddEntry("foo.weave.local.", "", mesh.UnknownPeerName, i)
 	}

 	doRequest := func(client *dns.Client, request *dns.Msg, port int, expectedErr error) *dns.Msg {
@@ -8,15 +8,16 @@ import (
 	"strings"
 	"time"

+	"github.com/weaveworks/mesh"
+
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 var now = func() int64 { return time.Now().Unix() }

 type Entry struct {
 	ContainerID string
-	Origin      router.PeerName
+	Origin      mesh.PeerName
 	Addr        address.Address
 	Hostname    string // as supplied
 	lHostname   string // lowercased (not exported, so not encoded by gob)
@@ -93,6 +94,9 @@ func (e1 *Entry) merge(e2 *Entry) bool {
 		e1.Version = e2.Version
 		e1.Tombstone = e2.Tombstone
 		return true
+	} else if e2.Version == e1.Version && e2.Tombstone > e1.Tombstone {
+		e1.Tombstone = e2.Tombstone
+		return true
 	}
 	return false
 }
@@ -105,6 +109,15 @@ func (e1 *Entry) addLowercase() {
 	e1.lHostname = strings.ToLower(e1.Hostname)
 }

+func (e1 *Entry) tombstone() bool {
+	if e1.Tombstone > 0 {
+		return false
+	}
+	e1.Tombstone = now()
+	e1.Version++
+	return true
+}
+
 func check(es SortableEntries) error {
 	if !sort.IsSorted(es) {
 		return fmt.Errorf("Not sorted!")
@@ -128,7 +141,7 @@ func (es *Entries) checkAndPanic() *Entries {
 	return es
 }

-func (es *Entries) add(hostname, containerid string, origin router.PeerName, addr address.Address) Entry {
+func (es *Entries) add(hostname, containerid string, origin mesh.PeerName, addr address.Address) Entry {
 	defer es.checkAndPanic().checkAndPanic()

 	entry := Entry{Hostname: hostname, lHostname: strings.ToLower(hostname),
@@ -176,14 +189,12 @@ func (es *Entries) merge(incoming Entries) Entries {
 }

 // f returning true means keep the entry.
-func (es *Entries) tombstone(ourname router.PeerName, f func(*Entry) bool) Entries {
+func (es *Entries) tombstone(ourname mesh.PeerName, f func(*Entry) bool) Entries {
 	defer es.checkAndPanic().checkAndPanic()

 	tombstoned := Entries{}
 	for i, e := range *es {
-		if f(&e) && e.Origin == ourname {
-			e.Version++
-			e.Tombstone = now()
+		if f(&e) && e.Origin == ourname && e.tombstone() {
 			(*es)[i] = e
 			tombstoned = append(tombstoned, e)
 		}
@@ -191,6 +202,7 @@ func (es *Entries) tombstone(ourname router.PeerName, f func(*Entry) bool) Entri
 	return tombstoned
 }

+// note f() may only modify entries such that they remain in order defined by less()
 func (es *Entries) filter(f func(*Entry) bool) {
 	defer es.checkAndPanic().checkAndPanic()

@@ -205,6 +217,16 @@ func (es *Entries) filter(f func(*Entry) bool) {
 	*es = (*es)[:i]
 }

+func (es Entries) findEqual(e *Entry) (*Entry, bool) {
+	i := sort.Search(len(es), func(i int) bool {
+		return !es[i].insensitiveLess(e)
+	})
+	if i < len(es) && es[i].equal(*e) {
+		return &es[i], true
+	}
+	return nil, false
+}
+
 func (es Entries) lookup(hostname string) Entries {
 	es.checkAndPanic()

@@ -245,12 +267,14 @@ type GossipData struct {
 	Entries
 }

-func (g *GossipData) Merge(o router.GossipData) {
+func (g *GossipData) Merge(o mesh.GossipData) mesh.GossipData {
 	other := o.(*GossipData)
-	g.Entries.merge(other.Entries)
-	if g.Timestamp < other.Timestamp {
-		g.Timestamp = other.Timestamp
+	gossip := g.copy()
+	gossip.Entries.merge(other.Entries)
+	if gossip.Timestamp < other.Timestamp {
+		gossip.Timestamp = other.Timestamp
 	}
+	return gossip
 }

 func (g *GossipData) Decode(msg []byte) error {
@@ -264,9 +288,7 @@ func (g *GossipData) Decode(msg []byte) error {
 }

 func (g *GossipData) Encode() [][]byte {
-	// Make a copy so we can sort: all outgoing data is sent in case-sensitive order
-	g2 := GossipData{Timestamp: g.Timestamp, Entries: make(Entries, len(g.Entries))}
-	copy(g2.Entries, g.Entries)
+	g2 := g.copy()
 	sort.Sort(CaseSensitive(g2.Entries))
 	buf := &bytes.Buffer{}
 	if err := gob.NewEncoder(buf).Encode(g2); err != nil {
@@ -274,3 +296,9 @@ func (g *GossipData) Encode() [][]byte {
 	}
 	return [][]byte{buf.Bytes()}
 }
+
+func (g *GossipData) copy() *GossipData {
+	g2 := &GossipData{Timestamp: g.Timestamp, Entries: make(Entries, len(g.Entries))}
+	copy(g2.Entries, g.Entries)
+	return g2
+}
@@ -4,9 +4,9 @@ import (
 	"testing"

 	"github.com/stretchr/testify/require"
+	"github.com/weaveworks/mesh"

 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 func l(es Entries) Entries {
@@ -28,21 +28,21 @@ func TestAdd(t *testing.T) {
 	now = func() int64 { return 1234 }

 	entries := Entries{}
-	entries.add("A", "", router.UnknownPeerName, address.Address(0))
+	entries.add("A", "", mesh.UnknownPeerName, address.Address(0))
 	expected := l(Entries{
-		Entry{Hostname: "A", Origin: router.UnknownPeerName, Addr: address.Address(0)},
+		Entry{Hostname: "A", Origin: mesh.UnknownPeerName, Addr: address.Address(0)},
 	})
 	require.Equal(t, entries, expected)

-	entries.tombstone(router.UnknownPeerName, func(e *Entry) bool { return e.Hostname == "A" })
+	entries.tombstone(mesh.UnknownPeerName, func(e *Entry) bool { return e.Hostname == "A" })
 	expected = l(Entries{
-		Entry{Hostname: "A", Origin: router.UnknownPeerName, Addr: address.Address(0), Version: 1, Tombstone: 1234},
+		Entry{Hostname: "A", Origin: mesh.UnknownPeerName, Addr: address.Address(0), Version: 1, Tombstone: 1234},
 	})
 	require.Equal(t, entries, expected)

-	entries.add("A", "", router.UnknownPeerName, address.Address(0))
+	entries.add("A", "", mesh.UnknownPeerName, address.Address(0))
 	expected = l(Entries{
-		Entry{Hostname: "A", Origin: router.UnknownPeerName, Addr: address.Address(0), Version: 2},
+		Entry{Hostname: "A", Origin: mesh.UnknownPeerName, Addr: address.Address(0), Version: 2},
 	})
 	require.Equal(t, entries, expected)
 }
@@ -78,7 +78,7 @@ func TestTombstone(t *testing.T) {

 	es := makeEntries("AB")

-	es.tombstone(router.UnknownPeerName, func(e *Entry) bool {
+	es.tombstone(mesh.UnknownPeerName, func(e *Entry) bool {
 		return e.Hostname == "B"
 	})
 	expected := l(Entries{
@@ -86,6 +86,21 @@ func TestTombstone(t *testing.T) {
 		Entry{Hostname: "B", Version: 1, Tombstone: 1234},
 	})
 	require.Equal(t, expected, es)
+
+	// Now try a merge including two entries which differ only in tombstone
+	e2 := make(Entries, len(es))
+	copy(e2, es)
+	e2[1].Tombstone = 5555
+
+	diff := es.merge(e2)
+
+	expected2 := l(Entries{
+		Entry{Hostname: "A"},
+		Entry{Hostname: "B", Version: 1, Tombstone: 5555},
+	})
+	require.Equal(t, expected2, es)
+	expectedDiff := l(Entries{Entry{Hostname: "B", Version: 1, Tombstone: 5555}})
+	require.Equal(t, expectedDiff, diff)
 }

 func TestDelete(t *testing.T) {
@@ -117,7 +132,7 @@ func TestGossipDataMerge(t *testing.T) {
 	g1 := GossipData{Entries: makeEntries("AcDf")}
 	g2 := GossipData{Entries: makeEntries("BEf")}

-	g1.Merge(&g2)
+	g3 := g1.Merge(&g2).(*GossipData)

-	require.Equal(t, GossipData{Entries: makeEntries("ABcDEf")}, g1)
+	require.Equal(t, GossipData{Entries: makeEntries("ABcDEf")}, *g3)
 }
@@ -40,16 +40,11 @@ func (n *Nameserver) HandleHTTP(router *mux.Router, dockerCli *docker.Client) {
 			return
 		}

-		if err := n.AddEntry(hostname, container, n.ourName, ip); err != nil {
-			n.badRequest(w, fmt.Errorf("Unable to add entry: %v", err))
-			return
-		}
+		n.AddEntry(hostname, container, n.ourName, ip)

 		if r.FormValue("check-alive") == "true" && dockerCli != nil && dockerCli.IsContainerNotRunning(container) {
 			n.infof("container '%s' is not running: removing", container)
-			if err := n.Delete(hostname, container, ipStr, ip); err != nil {
-				n.infof("failed to remove: %v", err)
-			}
+			n.Delete(hostname, container, ipStr, ip)
 		}

 		w.WriteHeader(204)
@@ -79,10 +74,7 @@ func (n *Nameserver) HandleHTTP(router *mux.Router, dockerCli *docker.Client) {
 			ipStr = "*"
 		}

-		if err := n.Delete(hostname, container, ipStr, ip); err != nil {
-			n.badRequest(w, fmt.Errorf("Unable to delete entries: %v", err))
-			return
-		}
+		n.Delete(hostname, container, ipStr, ip)
 		w.WriteHeader(204)
 	}
 	router.Methods("DELETE").Path("/name/{container}/{ip}").HandlerFunc(deleteHandler)
@@ -6,10 +6,10 @@ import (
 	"time"

 	"github.com/miekg/dns"
+	"github.com/weaveworks/mesh"

-	. "github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
 )

 const (
@@ -34,28 +34,24 @@ const (
 // - Update is O(n) for now
 type Nameserver struct {
 	sync.RWMutex
-	ourName router.PeerName
-	domain  string
-	gossip  router.Gossip
-	entries Entries
-	peers   *router.Peers
-	quit    chan struct{}
+	ourName     mesh.PeerName
+	domain      string
+	gossip      mesh.Gossip
+	entries     Entries
+	isKnownPeer func(mesh.PeerName) bool
+	quit        chan struct{}
 }

-func New(ourName router.PeerName, peers *router.Peers, domain string) *Nameserver {
-	ns := &Nameserver{
-		ourName: ourName,
-		domain:  dns.Fqdn(domain),
-		peers:   peers,
-		quit:    make(chan struct{}),
+func New(ourName mesh.PeerName, domain string, isKnownPeer func(mesh.PeerName) bool) *Nameserver {
+	return &Nameserver{
+		ourName:     ourName,
+		domain:      dns.Fqdn(domain),
+		isKnownPeer: isKnownPeer,
+		quit:        make(chan struct{}),
 	}
-	if peers != nil {
-		peers.OnGC(ns.PeerGone)
-	}
-	return ns
 }

-func (n *Nameserver) SetGossip(gossip router.Gossip) {
+func (n *Nameserver) SetGossip(gossip mesh.Gossip) {
 	n.gossip = gossip
 }

@@ -77,22 +73,22 @@ func (n *Nameserver) Stop() {
 	n.quit <- struct{}{}
 }

-func (n *Nameserver) broadcastEntries(es ...Entry) error {
-	if n.gossip != nil {
-		return n.gossip.GossipBroadcast(&GossipData{
-			Entries:   Entries(es),
-			Timestamp: now(),
-		})
+func (n *Nameserver) broadcastEntries(es ...Entry) {
+	if n.gossip == nil || len(es) == 0 {
+		return
 	}
-	return nil
+	n.gossip.GossipBroadcast(&GossipData{
+		Entries:   Entries(es),
+		Timestamp: now(),
+	})
 }

-func (n *Nameserver) AddEntry(hostname, containerid string, origin router.PeerName, addr address.Address) error {
-	n.infof("adding entry %s -> %s", hostname, addr.String())
+func (n *Nameserver) AddEntry(hostname, containerid string, origin mesh.PeerName, addr address.Address) {
 	n.Lock()
+	n.infof("adding entry for %s: %s -> %s", containerid, hostname, addr.String())
 	entry := n.entries.add(hostname, containerid, origin, addr)
 	n.Unlock()
-	return n.broadcastEntries(entry)
+	n.broadcastEntries(entry)
 }

 func (n *Nameserver) Lookup(hostname string) []address.Address {
@@ -125,7 +121,8 @@ func (n *Nameserver) ReverseLookup(ip address.Address) (string, error) {
 	return match.Hostname, nil
 }

-func (n *Nameserver) ContainerStarted(ident string) {}
+func (n *Nameserver) ContainerStarted(ident string)   {}
+func (n *Nameserver) ContainerDestroyed(ident string) {}

 func (n *Nameserver) ContainerDied(ident string) {
 	n.Lock()
@@ -137,23 +134,19 @@ func (n *Nameserver) ContainerDied(ident string) {
 		return false
 	})
 	n.Unlock()
-	if len(entries) > 0 {
-		if err := n.broadcastEntries(entries...); err != nil {
-			n.errorf("failed to broadcast container %s death: %v", ident, err)
-		}
-	}
+	n.broadcastEntries(entries...)
 }

-func (n *Nameserver) PeerGone(peer *router.Peer) {
+func (n *Nameserver) PeerGone(peer mesh.PeerName) {
 	n.infof("peer %s gone", peer.String())
 	n.Lock()
 	defer n.Unlock()
 	n.entries.filter(func(e *Entry) bool {
-		return e.Origin != peer.Name
+		return e.Origin != peer
 	})
 }

-func (n *Nameserver) Delete(hostname, containerid, ipStr string, ip address.Address) error {
+func (n *Nameserver) Delete(hostname, containerid, ipStr string, ip address.Address) {
 	n.Lock()
 	n.infof("tombstoning hostname=%s, container=%s, ip=%s", hostname, containerid, ipStr)
 	entries := n.entries.tombstone(n.ourName, func(e *Entry) bool {
@@ -173,7 +166,7 @@ func (n *Nameserver) Delete(hostname, containerid, ipStr string, ip address.Addr
 		return true
 	})
 	n.Unlock()
-	return n.broadcastEntries(entries...)
+	n.broadcastEntries(entries...)
 }

 func (n *Nameserver) deleteTombstones() {
@@ -185,7 +178,7 @@ func (n *Nameserver) deleteTombstones() {
 	})
 }

-func (n *Nameserver) Gossip() router.GossipData {
+func (n *Nameserver) Gossip() mesh.GossipData {
 	n.RLock()
 	defer n.RUnlock()
 	gossip := &GossipData{
@@ -196,29 +189,56 @@ func (n *Nameserver) Gossip() router.GossipData {
 	return gossip
 }

-func (n *Nameserver) OnGossipUnicast(sender router.PeerName, msg []byte) error {
+func (n *Nameserver) OnGossipUnicast(sender mesh.PeerName, msg []byte) error {
 	return nil
 }

-func (n *Nameserver) receiveGossip(msg []byte) (router.GossipData, router.GossipData, error) {
+func (n *Nameserver) receiveGossip(msg []byte) (mesh.GossipData, mesh.GossipData, error) {
 	var gossip GossipData
 	if err := gossip.Decode(msg); err != nil {
 		return nil, nil, err
 	}
 	if delta := gossip.Timestamp - now(); delta > gossipWindow || delta < -gossipWindow {
-		return nil, nil, fmt.Errorf("clock skew of %d detected", delta)
+		return nil, nil, fmt.Errorf("host clock skew of %ds exceeds %ds limit", delta, gossipWindow)
 	}

+	// Filter to remove entries from unknown peers, done before we take
+	// the nameserver lock, so we don't have to worry what isKnownPeer locks.
+	gossip.Entries.filter(func(e *Entry) bool {
+		return n.isKnownPeer(e.Origin)
+	})
+
+	var overriddenEntries []Entry
 	n.Lock()
-	defer n.Unlock()

-	if n.peers != nil {
-		gossip.Entries.filter(func(e *Entry) bool {
-			return n.peers.Fetch(e.Origin) != nil
-		})
-	}
+	// Check entries claiming to originate from us against our current data
+	gossip.Entries.filter(func(e *Entry) bool {
+		if e.Origin == n.ourName {
+			if ourEntry, ok := n.entries.findEqual(e); ok {
+				if ourEntry.Version < e.Version ||
+					(ourEntry.Version == e.Version && ourEntry.Tombstone != e.Tombstone) {
+					// Take our version of the data, but make the version higher than the incoming
+					nextVersion := e.Version + 1
+					*e = *ourEntry
+					e.Version = nextVersion
+					overriddenEntries = append(overriddenEntries, *e)
+				}
+			} else { // We have no entry matching the one that came in with us as Origin
+				if e.tombstone() {
+					overriddenEntries = append(overriddenEntries, *e)
+				}
+			}
+		}
+		return true
+	})

 	newEntries := n.entries.merge(gossip.Entries)
+	n.Unlock() // unlock before attempting to broadcast
+
+	// Note that all overriddenEntries have been merged into our entries, either
+	// because we forced the version higher or because they were missing before.
+	n.broadcastEntries(overriddenEntries...)
+
 	if len(newEntries) > 0 {
 		return &GossipData{Entries: newEntries, Timestamp: now()}, &gossip, nil
 	}
@@ -227,24 +247,29 @@ func (n *Nameserver) receiveGossip(msg []byte) (router.GossipData, router.Gossip

 // merge received data into state and return "everything new I've
 // just learnt", or nil if nothing in the received data was new
-func (n *Nameserver) OnGossip(msg []byte) (router.GossipData, error) {
+func (n *Nameserver) OnGossip(msg []byte) (mesh.GossipData, error) {
 	newEntries, _, err := n.receiveGossip(msg)
 	return newEntries, err
 }

 // merge received data into state and return a representation of
 // the received data, for further propagation
-func (n *Nameserver) OnGossipBroadcast(_ router.PeerName, msg []byte) (router.GossipData, error) {
+func (n *Nameserver) OnGossipBroadcast(_ mesh.PeerName, msg []byte) (mesh.GossipData, error) {
 	_, entries, err := n.receiveGossip(msg)
 	return entries, err
 }

+// Logging
+
 func (n *Nameserver) infof(fmt string, args ...interface{}) {
-	Log.Infof("[nameserver %s] "+fmt, append([]interface{}{n.ourName}, args...)...)
+	n.logf(common.Log.Infof, fmt, args...)
 }
 func (n *Nameserver) debugf(fmt string, args ...interface{}) {
-	Log.Debugf("[nameserver %s] "+fmt, append([]interface{}{n.ourName}, args...)...)
+	n.logf(common.Log.Debugf, fmt, args...)
 }
 func (n *Nameserver) errorf(fmt string, args ...interface{}) {
-	Log.Errorf("[nameserver %s] "+fmt, append([]interface{}{n.ourName}, args...)...)
+	n.logf(common.Log.Errorf, fmt, args...)
+}
+func (n *Nameserver) logf(f func(string, ...interface{}), fmt string, args ...interface{}) {
+	f("[nameserver %s] "+fmt, append([]interface{}{n.ourName}, args...)...)
 }
@@ -10,20 +10,23 @@ import (
 	"time"

 	"github.com/stretchr/testify/require"
+	"github.com/weaveworks/mesh"

 	"github.com/weaveworks/weave/net/address"
-	"github.com/weaveworks/weave/router"
-	wt "github.com/weaveworks/weave/testing"
 	"github.com/weaveworks/weave/testing/gossip"
 )

+func makeNameserver(name mesh.PeerName) *Nameserver {
+	return New(name, "", func(mesh.PeerName) bool { return true })
+}
+
 func makeNetwork(size int) ([]*Nameserver, *gossip.TestRouter) {
 	gossipRouter := gossip.NewTestRouter(0.0)
 	nameservers := make([]*Nameserver, size)

 	for i := 0; i < size; i++ {
-		name, _ := router.PeerNameFromString(fmt.Sprintf("%02d:00:00:02:00:00", i))
-		nameserver := New(name, nil, "")
+		name, _ := mesh.PeerNameFromString(fmt.Sprintf("%02d:00:00:02:00:00", i))
+		nameserver := makeNameserver(name)
 		nameserver.SetGossip(gossipRouter.Connect(nameserver.ourName, nameserver))
 		nameserver.Start()
 		nameservers[i] = nameserver
@@ -40,7 +43,7 @@ func stopNetwork(nameservers []*Nameserver, grouter *gossip.TestRouter) {
 }

 type pair struct {
-	origin router.PeerName
+	origin mesh.PeerName
 	addr   address.Address
 }

@@ -72,12 +75,6 @@ func (m mapping) Addrs() []address.Address {
 }

 func TestNameservers(t *testing.T) {
-	wt.RunWithTimeout(t, 2*time.Minute, func() {
-		testNameservers(t)
-	})
-}
-
-func testNameservers(t *testing.T) {
 	//common.SetLogLevel("debug")

 	lookupTimeout := 10 // ms
@@ -87,7 +84,7 @@ func testNameservers(t *testing.T) {
 	badNameservers := nameservers[25:]
 	// This subset will remain well-connected, and we will deal mainly with them
 	nameservers = nameservers[:25]
-	nameserversByName := map[router.PeerName]*Nameserver{}
+	nameserversByName := map[mesh.PeerName]*Nameserver{}
 	for _, n := range nameservers {
 		nameserversByName[n.ourName] = n
 	}
@@ -120,7 +117,7 @@ func testNameservers(t *testing.T) {
 		mapping := mapping{hostname, []pair{{nameserver.ourName, addr}}}
 		mappings = append(mappings, mapping)

-		require.Nil(t, nameserver.AddEntry(hostname, "", nameserver.ourName, addr))
+		nameserver.AddEntry(hostname, "", nameserver.ourName, addr)
 		check(nameserver, mapping)
 	}

@@ -135,14 +132,14 @@ func testNameservers(t *testing.T) {
 		mapping.addrs = append(mapping.addrs, pair{nameserver.ourName, addr})
 		mappings[i] = mapping

-		require.Nil(t, nameserver.AddEntry(mapping.hostname, "", nameserver.ourName, addr))
+		nameserver.AddEntry(mapping.hostname, "", nameserver.ourName, addr)
 		check(nameserver, mapping)
 	}

 	loseConnection := func() {
 		nameserver1 := badNameservers[rand.Intn(len(badNameservers))]
 		nameserver2 := nameservers[rand.Intn(len(nameservers))]
-		nameserver1.PeerGone(&router.Peer{Name: nameserver2.ourName})
+		nameserver1.PeerGone(nameserver2.ourName)
 	}

 	deleteMapping := func() {
@@ -160,7 +157,7 @@ func testNameservers(t *testing.T) {
 		mappings[i] = mapping
 		nameserver := nameserversByName[pair.origin]

-		require.Nil(t, nameserver.Delete(mapping.hostname, "*", pair.addr.String(), pair.addr))
+		nameserver.Delete(mapping.hostname, "*", pair.addr.String(), pair.addr)
 		check(nameserver, mapping)
 	}

@@ -222,22 +219,20 @@ func testNameservers(t *testing.T) {
 }

 func TestContainerAndPeerDeath(t *testing.T) {
-	peername, err := router.PeerNameFromString("00:00:00:02:00:00")
+	peername, err := mesh.PeerNameFromString("00:00:00:02:00:00")
 	require.Nil(t, err)
-	nameserver := New(peername, nil, "")
+	nameserver := makeNameserver(peername)

-	err = nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
-	require.Nil(t, err)
+	nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
 	require.Equal(t, []address.Address{0}, nameserver.Lookup("hostname"))

 	nameserver.ContainerDied("containerid")
 	require.Equal(t, []address.Address{}, nameserver.Lookup("hostname"))

-	err = nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
-	require.Nil(t, err)
+	nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
 	require.Equal(t, []address.Address{0}, nameserver.Lookup("hostname"))

-	nameserver.PeerGone(&router.Peer{Name: peername})
+	nameserver.PeerGone(peername)
 	require.Equal(t, []address.Address{}, nameserver.Lookup("hostname"))
 }

@@ -246,19 +241,17 @@ func TestTombstoneDeletion(t *testing.T) {
 	defer func() { now = oldNow }()
 	now = func() int64 { return 1234 }

-	peername, err := router.PeerNameFromString("00:00:00:02:00:00")
+	peername, err := mesh.PeerNameFromString("00:00:00:02:00:00")
 	require.Nil(t, err)
-	nameserver := New(peername, nil, "")
+	nameserver := makeNameserver(peername)

-	err = nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
-	require.Nil(t, err)
+	nameserver.AddEntry("hostname", "containerid", peername, address.Address(0))
 	require.Equal(t, []address.Address{0}, nameserver.Lookup("hostname"))

 	nameserver.deleteTombstones()
 	require.Equal(t, []address.Address{0}, nameserver.Lookup("hostname"))

-	err = nameserver.Delete("hostname", "containerid", "", address.Address(0))
-	require.Nil(t, err)
+	nameserver.Delete("hostname", "containerid", "", address.Address(0))
 	require.Equal(t, []address.Address{}, nameserver.Lookup("hostname"))
 	require.Equal(t, l(Entries{Entry{
 		ContainerID: "containerid",
@@ -1,10 +1,11 @@
 package nameserver

 type Status struct {
-	Domain  string
-	Address string
-	TTL     uint32
-	Entries []EntryStatus
+	Domain   string
+	Upstream []string
+	Address  string
+	TTL      uint32
+	Entries  []EntryStatus
 }

 type EntryStatus struct {
@@ -37,6 +38,7 @@ func NewStatus(ns *Nameserver, dnsServer *DNSServer) *Status {

 	return &Status{
 		dnsServer.domain,
+		dnsServer.upstream.Config().Servers,
 		dnsServer.address,
 		dnsServer.ttl,
 		entryStatusSlice}
@@ -10,6 +10,7 @@ import (
 // Using 32-bit integer to represent IPv4 address
 type Address uint32
 type Offset uint32
+type Count uint32

 type Range struct {
 	Start, End Address // [Start, End); Start <= End
@@ -18,8 +19,8 @@ type Range struct {
 func NewRange(start Address, size Offset) Range {
 	return Range{Start: start, End: Add(start, size)}
 }
-func (r Range) Size() Offset               { return Subtract(r.End, r.Start) }
-func (r Range) String() string             { return fmt.Sprintf("[%s-%s)", r.Start, r.End) }
+func (r Range) Size() Count                { return Length(r.End, r.Start) }
+func (r Range) String() string             { return fmt.Sprintf("%s-%s", r.Start, r.End-1) }
 func (r Range) Overlaps(or Range) bool     { return !(r.Start >= or.End || r.End <= or.Start) }
 func (r Range) Contains(addr Address) bool { return addr >= r.Start && addr < r.End }

@@ -31,14 +32,81 @@ func (r Range) AsCIDRString() string {
 		}
 		prefixLen--
 	}
-	return CIDR{Start: r.Start, PrefixLen: prefixLen}.String()
+	return CIDR{Addr: r.Start, PrefixLen: prefixLen}.String()
+}
+
+// return the highest bit set in v
+// algorithm from http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
+func msb(v Count) Count {
+	v |= v >> 1
+	v |= v >> 2
+	v |= v >> 4
+	v |= v >> 8
+	v |= v >> 16
+	// Cast to 64-bit to avoid overflow when original v >= 0x80000000
+	return Count((uint64(v) + 1) / 2)
+}
+
+func (r Range) BiggestCIDRRange() Range {
+	sizeMsb := Offset(msb(r.Size()))
+	maskedSize := Offset(r.Size()) & (sizeMsb - 1)
+	maskedStart := Offset(r.Start) & (sizeMsb - 1)
+	if maskedStart == 0 {
+		return NewRange(r.Start, sizeMsb)
+	}
+	if sizeMsb-maskedStart <= maskedSize {
+		return NewRange(Add(r.Start, sizeMsb-maskedStart), sizeMsb)
+	}
+	size := sizeMsb / 2
+	if size >= maskedStart {
+		return NewRange(Add(r.Start, size-maskedStart), size)
+	}
+	return NewRange(Add(r.Start, sizeMsb-maskedStart), size)
+}
+
+func MakeCIDR(subnet CIDR, addr Address) CIDR {
+	return CIDR{Addr: addr, PrefixLen: subnet.PrefixLen}
 }

 type CIDR struct {
-	Start     Address
+	Addr      Address
 	PrefixLen int
 }

+// CIDRs returns a list of CIDR-aligned ranges which cover this range.
+func (r Range) CIDRs() []CIDR {
+	const (
+		fullMask         = ^Address(0)
+		cidrMaxPrefixLen = 32
+	)
+	var cidrs []CIDR
+
+	for start, end := r.Start, r.End-1; end >= start; {
+		mask, prefixLen := fullMask, cidrMaxPrefixLen
+		// Find the smallest mask which would cover some part of [start;end].
+		// Once we found such, apply it by OR'ing
+		for mask > 0 {
+			tmpMask := mask << 1
+			// Check whether mask neither too short nor too long
+			if (start&tmpMask) != start || (start|^tmpMask) > end {
+				break
+			}
+			mask = tmpMask
+			prefixLen--
+		}
+		cidrs = append(cidrs, CIDR{start, prefixLen})
+		// Apply mask
+		start |= ^mask
+		// Check for overflow
+		if start+1 < start {
+			break
+		}
+		start++
+	}
+
+	return cidrs
+}
+
 func ParseIP(s string) (Address, error) {
 	if ip := net.ParseIP(s); ip != nil {
 		return FromIP4(ip), nil
@@ -46,29 +114,50 @@ func ParseIP(s string) (Address, error) {
 	return 0, &net.ParseError{Type: "IP Address", Text: s}
 }

-func ParseCIDR(s string) (Address, CIDR, error) {
+func ParseCIDR(s string) (CIDR, error) {
 	if ip, ipnet, err := net.ParseCIDR(s); err != nil {
-		return 0, CIDR{}, err
+		return CIDR{}, err
 	} else if ipnet.IP.To4() == nil {
-		return 0, CIDR{}, &net.ParseError{Type: "Non-IPv4 address not supported", Text: s}
+		return CIDR{}, &net.ParseError{Type: "Non-IPv4 address not supported", Text: s}
 	} else {
 		prefixLen, _ := ipnet.Mask.Size()
-		return FromIP4(ip), CIDR{Start: FromIP4(ipnet.IP), PrefixLen: prefixLen}, nil
+		return CIDR{Addr: FromIP4(ip), PrefixLen: prefixLen}, nil
 	}
 }

+func NewCIDRs(ranges []Range) (cidrs []CIDR) {
+	for _, r := range ranges {
+		cidrs = append(cidrs, r.CIDRs()...)
+	}
+	return cidrs
+}
+
+func (cidr CIDR) Start() Address {
+	return cidr.Addr
+}
+
+// cidr = [Start; End)
+func (cidr CIDR) End() Address {
+	return cidr.Range().End
+}
+
+func (cidr CIDR) IsSubnet() bool {
+	mask := cidr.Size() - 1
+	return Offset(cidr.Addr)&mask == 0
+}
+
 func (cidr CIDR) Size() Offset { return 1 << uint(32-cidr.PrefixLen) }

 func (cidr CIDR) Range() Range {
-	return NewRange(cidr.Start, cidr.Size())
+	return NewRange(cidr.Addr, cidr.Size())
 }
 func (cidr CIDR) HostRange() Range {
 	// Respect RFC1122 exclusions of first and last addresses
-	return NewRange(cidr.Start+1, cidr.Size()-2)
+	return NewRange(cidr.Addr+1, cidr.Size()-2)
 }

 func (cidr CIDR) String() string {
-	return fmt.Sprintf("%s/%d", cidr.Start.String(), cidr.PrefixLen)
+	return fmt.Sprintf("%s/%d", cidr.Addr.String(), cidr.PrefixLen)
 }

 // FromIP4 converts an ipv4 address to our integer address type
@@ -107,7 +196,12 @@ func Subtract(a, b Address) Offset {
 	return Offset(a - b)
 }

-func Min(a, b Offset) Offset {
+func Length(a, b Address) Count {
+	common.Assert(a >= b)
+	return Count(a - b)
+}
+
+func Min(a, b Count) Count {
 	if a > b {
 		return b
 	}
@@ -0,0 +1,69 @@
+package address
+
+import (
+	"testing"
+	"testing/quick"
+
+	"github.com/stretchr/testify/require"
+)
+
+func isPower2(x Count) bool {
+	if x == 0 {
+		return false
+	}
+	for ; x > 1; x /= 2 {
+		if x&1 != 0 {
+			return false
+		}
+	}
+	return true
+}
+
+func TestBiggestPow2AlignedRange(t *testing.T) {
+	require.Equal(t, NewRange(0, 1), NewRange(0, 1).BiggestCIDRRange())
+	require.Equal(t, NewRange(1, 1), NewRange(1, 2).BiggestCIDRRange())
+	require.Equal(t, NewRange(2, 2), NewRange(1, 3).BiggestCIDRRange())
+	require.Equal(t, NewRange(0, 0x40000000), NewRange(0, 0x7fffffff).BiggestCIDRRange())
+	require.Equal(t, NewRange(0xfffffffe, 1), NewRange(0xfffffffe, 1).BiggestCIDRRange())
+	prop := func(start Address, size Offset) bool {
+		if size > Offset(0xffffffff)-Offset(start) { // out of range
+			return true
+		}
+		r := NewRange(start, size)
+		result := r.BiggestCIDRRange()
+		return r.Contains(result.Start) &&
+			r.Contains(result.End-1) &&
+			isPower2(result.Size()) &&
+			result.Size() > r.Size()/4 &&
+			Count(result.Start)%result.Size() == 0
+	}
+	require.NoError(t, quick.Check(prop, &quick.Config{MaxCount: 1000000}))
+}
+
+func ip(s string) Address {
+	addr, _ := ParseIP(s)
+	return addr
+}
+
+func cidr(s string) CIDR {
+	c, err := ParseCIDR(s)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+func TestCIDRs(t *testing.T) {
+	start := ip("10.0.0.1")
+	end := ip("10.0.0.9")
+	r := NewRange(start, Subtract(end, start))
+	require.Equal(t,
+		[]CIDR{cidr("10.0.0.1/32"), cidr("10.0.0.2/31"), cidr("10.0.0.4/30"), cidr("10.0.0.8/32")},
+		r.CIDRs())
+}
+
+func TestCIDRStartAndEnd(t *testing.T) {
+	cidr, _ := ParseCIDR("10.0.0.0/24")
+	require.Equal(t, ip("10.0.0.0"), cidr.Start(), "")
+	require.Equal(t, ip("10.0.1.0"), cidr.End(), "")
+}
@@ -0,0 +1,43 @@
+package net
+
+import "fmt"
+import "io"
+import "os"
+
+// Configure the ARP cache parameters for the given interface.  This
+// makes containers react more quickly to a change in the MAC address
+// associated with an IP address.
+func ConfigureARPCache(name string) error {
+	if err := sysctl(fmt.Sprintf("net/ipv4/neigh/%s/base_reachable_time", name), "5"); err != nil {
+		return err
+	}
+	if err := sysctl(fmt.Sprintf("net/ipv4/neigh/%s/delay_first_probe_time", name), "2"); err != nil {
+		return err
+	}
+	if err := sysctl(fmt.Sprintf("net/ipv4/neigh/%s/ucast_solicit", name), "1"); err != nil {
+		return err
+	}
+	return nil
+}
+
+func sysctl(variable, value string) error {
+	f, err := os.OpenFile(fmt.Sprintf("/proc/sys/%s", variable), os.O_WRONLY, 0)
+	if err != nil {
+		return err
+	}
+
+	n, err := io.WriteString(f, value)
+	if err != nil {
+		return err
+	}
+	if n < len(value) {
+		return io.ErrShortWrite
+	}
+
+	err = f.Close()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
@@ -0,0 +1,53 @@
+package net
+
+import (
+	"github.com/vishvananda/netlink"
+)
+
+type BridgeType int
+
+const (
+	WeaveBridgeName = "weave"
+	DatapathName    = "datapath"
+
+	None BridgeType = iota
+	Bridge
+	Fastdp
+	BridgedFastdp
+	Inconsistent
+)
+
+func DetectBridgeType(weaveBridgeName, datapathName string) BridgeType {
+	bridge, _ := netlink.LinkByName(weaveBridgeName)
+	datapath, _ := netlink.LinkByName(datapathName)
+
+	switch {
+	case bridge == nil && datapath == nil:
+		return None
+	case isBridge(bridge) && datapath == nil:
+		return Bridge
+	case isDatapath(bridge) && datapath == nil:
+		return Fastdp
+	case isDatapath(datapath) && isBridge(bridge):
+		return BridgedFastdp
+	default:
+		return Inconsistent
+	}
+}
+
+func isBridge(link netlink.Link) bool {
+	_, isBridge := link.(*netlink.Bridge)
+	return isBridge
+}
+
+func isDatapath(link netlink.Link) bool {
+	switch link.(type) {
+	case *netlink.GenericLink:
+		return link.Type() == "openvswitch"
+	case *netlink.Device:
+		// Assume it's our openvswitch device, and the kernel has not been updated to report the kind.
+		return true
+	default:
+		return false
+	}
+}
@@ -0,0 +1,60 @@
+package net
+
+import "fmt"
+import "syscall"
+import "unsafe"
+
+const (
+	SIOCETHTOOL     = 0x8946     // linux/sockios.h
+	ETHTOOL_GTXCSUM = 0x00000016 // linux/ethtool.h
+	ETHTOOL_STXCSUM = 0x00000017 // linux/ethtool.h
+	IFNAMSIZ        = 16         // linux/if.h
+)
+
+// linux/if.h 'struct ifreq'
+type IFReqData struct {
+	Name [IFNAMSIZ]byte
+	Data uintptr
+}
+
+// linux/ethtool.h 'struct ethtool_value'
+type EthtoolValue struct {
+	Cmd  uint32
+	Data uint32
+}
+
+func ioctlEthtool(fd int, argp uintptr) error {
+	_, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(fd), uintptr(SIOCETHTOOL), argp)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
+
+// Disable TX checksum offload on specified interface
+func EthtoolTXOff(name string) error {
+	if len(name)+1 > IFNAMSIZ {
+		return fmt.Errorf("name too long")
+	}
+
+	socket, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(socket)
+
+	// Request current value
+	value := EthtoolValue{Cmd: ETHTOOL_GTXCSUM}
+	request := IFReqData{Data: uintptr(unsafe.Pointer(&value))}
+	copy(request.Name[:], name)
+
+	if err := ioctlEthtool(socket, uintptr(unsafe.Pointer(&request))); err != nil {
+		return err
+	}
+	if value.Data == 0 { // if already off, don't try to change
+		return nil
+	}
+
+	value = EthtoolValue{ETHTOOL_STXCSUM, 0}
+	return ioctlEthtool(socket, uintptr(unsafe.Pointer(&request)))
+}
@@ -5,28 +5,35 @@ import (
 	"net"
 	"syscall"

-	"github.com/vishvananda/netlink/nl"
+	"github.com/vishvananda/netlink"
 )

 // Wait for an interface to come up.
 func EnsureInterface(ifaceName string) (*net.Interface, error) {
-	s, err := nl.Subscribe(syscall.NETLINK_ROUTE, syscall.RTNLGRP_LINK)
-	if err != nil {
-		return nil, err
-	}
-	defer s.Close()
-	iface, err := ensureInterface(s, ifaceName)
+	iface, err := ensureInterface(ifaceName)
 	if err != nil {
 		return nil, err
 	}
 	return iface, err
 }

-func ensureInterface(s *nl.NetlinkSocket, ifaceName string) (*net.Interface, error) {
+func ensureInterface(ifaceName string) (*net.Interface, error) {
+	ch := make(chan netlink.LinkUpdate)
+	// NB: We do not supply (and eventually close) a 'done' channel
+	// here since that can cause incorrect file descriptor
+	// re-usage. See https://github.com/weaveworks/weave/issues/2120
+	if err := netlink.LinkSubscribe(ch, nil); err != nil {
+		return nil, err
+	}
+	// check for currently-existing interface after subscribing, to avoid race
 	if iface, err := findInterface(ifaceName); err == nil {
 		return iface, nil
 	}
-	netlinkReceiveUntil(s, matchIfName(ifaceName))
+	for update := range ch {
+		if ifaceName == update.Link.Attrs().Name && update.IfInfomsg.Flags&syscall.IFF_UP != 0 {
+			break
+		}
+	}
 	iface, err := findInterface(ifaceName)
 	return iface, err
 }
@@ -35,21 +42,35 @@ func ensureInterface(s *nl.NetlinkSocket, ifaceName string) (*net.Interface, err
 // This matches the behaviour in 'weave attach', which is the only context in which
 // we expect this to be called.  If you change one, change the other to match.
 func EnsureInterfaceAndMcastRoute(ifaceName string) (*net.Interface, error) {
-	s, err := nl.Subscribe(syscall.NETLINK_ROUTE, syscall.RTNLGRP_LINK, syscall.RTNLGRP_IPV4_ROUTE)
+	iface, err := ensureInterface(ifaceName)
 	if err != nil {
 		return nil, err
 	}
-	defer s.Close()
-	iface, err := ensureInterface(s, ifaceName)
-	if err != nil {
+	ch := make(chan netlink.RouteUpdate)
+	if err := netlink.RouteSubscribe(ch, nil); err != nil {
 		return nil, err
 	}
 	dest := net.IPv4(224, 0, 0, 0)
-	if CheckRouteExists(ifaceName, dest) {
-		return iface, err
+	check := func(route netlink.Route) bool {
+		return route.Dst != nil && route.Dst.IP.Equal(dest)
 	}
-	netlinkReceiveUntil(s, matchRoute(ifaceName, dest))
-	return iface, err
+	// check for currently-existing route after subscribing, to avoid race
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, err
+	}
+	for _, route := range routes {
+		if check(route) {
+			return iface, nil
+		}
+	}
+	for update := range ch {
+		if check(update.Route) {
+			return iface, nil
+		}
+	}
+	// should never get here
+	return iface, nil
 }

 func findInterface(ifaceName string) (iface *net.Interface, err error) {
@@ -61,40 +82,3 @@ func findInterface(ifaceName string) (iface *net.Interface, err error) {
 	}
 	return
 }
-
-func netlinkReceiveUntil(s *nl.NetlinkSocket, f func(syscall.NetlinkMessage) (bool, error)) error {
-	for {
-		msgs, err := s.Receive()
-		if err != nil {
-			return err
-		}
-		for _, m := range msgs {
-			if done, err := f(m); done {
-				return err
-			}
-		}
-	}
-}
-
-func matchIfName(ifaceName string) func(m syscall.NetlinkMessage) (bool, error) {
-	return func(m syscall.NetlinkMessage) (bool, error) {
-		switch m.Header.Type {
-		case syscall.RTM_NEWLINK: // receive this type for link 'up'
-			ifmsg := nl.DeserializeIfInfomsg(m.Data)
-			attrs, err := syscall.ParseNetlinkRouteAttr(&m)
-			if err != nil {
-				return true, err
-			}
-			name := ""
-			for _, attr := range attrs {
-				if attr.Attr.Type == syscall.IFA_LABEL {
-					name = string(attr.Value[:len(attr.Value)-1])
-				}
-			}
-			if ifaceName == name && ifmsg.Flags&syscall.IFF_UP != 0 {
-				return true, nil
-			}
-		}
-		return false, nil
-	}
-}
@@ -0,0 +1,18 @@
+package net
+
+import (
+	"fmt"
+	"net"
+	"os"
+)
+
+func ListenUnixSocket(pathname string) (net.Listener, error) {
+	if err := os.Remove(pathname); err != nil && !os.IsNotExist(err) {
+		return nil, fmt.Errorf("Error removing existing unix socket: %s", err)
+	}
+	listener, err := net.Listen("unix", pathname)
+	if err != nil {
+		return nil, fmt.Errorf("ListenUnixSocket failed: %s", err)
+	}
+	return listener, nil
+}
@@ -0,0 +1,65 @@
+package net
+
+import (
+	"errors"
+	"runtime"
+
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+)
+
+var ErrLinkNotFound = errors.New("Link not found")
+
+// NB: The following function is unsafe, because:
+//     - It changes a network namespace (netns) of an OS thread which runs
+//       the function. During execution, the Go runtime might clone a new OS thread
+//       for scheduling other go-routines, thus they might end up running in
+//       a "wrong" netns.
+//     - runtime.LockOSThread does not guarantee that a spawned go-routine on
+//       the locked thread will be run by it. Thus, the work function is
+//       not allowed to spawn any go-routine which is dependent on the given netns.
+
+//     Please see https://github.com/weaveworks/weave/issues/2388#issuecomment-228365069
+//     for more details and make sure that you understand the implications before
+//     using the function!
+func WithNetNSUnsafe(ns netns.NsHandle, work func() error) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	oldNs, err := netns.Get()
+	if err == nil {
+		defer oldNs.Close()
+
+		err = netns.Set(ns)
+		if err == nil {
+			defer netns.Set(oldNs)
+
+			err = work()
+		}
+	}
+
+	return err
+}
+
+func WithNetNSLinkUnsafe(ns netns.NsHandle, ifName string, work func(link netlink.Link) error) error {
+	return WithNetNSUnsafe(ns, func() error {
+		link, err := netlink.LinkByName(ifName)
+		if err != nil {
+			if err.Error() == errors.New("Link not found").Error() {
+				return ErrLinkNotFound
+			}
+			return err
+		}
+		return work(link)
+	})
+}
+
+func WithNetNSLinkByPidUnsafe(pid int, ifName string, work func(link netlink.Link) error) error {
+	ns, err := netns.GetFromPid(pid)
+	if err != nil {
+		return err
+	}
+	defer ns.Close()
+
+	return WithNetNSLinkUnsafe(ns, ifName, work)
+}
@@ -3,16 +3,15 @@ package net
 import (
 	"fmt"
 	"net"
-	"syscall"
+	"os"

 	"github.com/vishvananda/netlink"
-	"github.com/vishvananda/netlink/nl"
 )

 // A network is considered free if it does not overlap any existing
 // routes on this host. This is the same approach taken by Docker.
 func CheckNetworkFree(subnet *net.IPNet, ignoreIfaceNames map[string]struct{}) error {
-	return forEachRoute(ignoreIfaceNames, func(name string, route netlink.Route) error {
+	return forEachRoute(ignoreIfaceNames, func(route netlink.Route) error {
 		if route.Dst != nil && overlaps(route.Dst, subnet) {
 			return fmt.Errorf("Network %s overlaps with existing route %s on host.", subnet, route.Dst)
 		}
@@ -28,7 +27,7 @@ func overlaps(n1, n2 *net.IPNet) bool {
 // For a specific address, we only care if it is actually *inside* an
 // existing route, because weave-local traffic never hits IP routing.
 func CheckAddressOverlap(addr net.IP, ignoreIfaceNames map[string]struct{}) error {
-	return forEachRoute(ignoreIfaceNames, func(name string, route netlink.Route) error {
+	return forEachRoute(ignoreIfaceNames, func(route netlink.Route) error {
 		if route.Dst != nil && route.Dst.Contains(addr) {
 			return fmt.Errorf("Address %s overlaps with existing route %s on host.", addr, route.Dst)
 		}
@@ -36,80 +35,37 @@ func CheckAddressOverlap(addr net.IP, ignoreIfaceNames map[string]struct{}) erro
 	})
 }

-func forEachRoute(ignoreIfaceNames map[string]struct{}, check func(name string, r netlink.Route) error) error {
+func forEachRoute(ignoreIfaceNames map[string]struct{}, check func(r netlink.Route) error) error {
+	ignoreIfaceIndices := make(map[int]struct{})
+	for ifaceName := range ignoreIfaceNames {
+		if iface, err := net.InterfaceByName(ifaceName); err == nil {
+			ignoreIfaceIndices[iface.Index] = struct{}{}
+		}
+	}
 	routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
 	if err != nil {
 		return err
 	}
 	for _, route := range routes {
-		link, err := netlink.LinkByIndex(route.LinkIndex)
-		if err == nil {
-			if _, found := ignoreIfaceNames[link.Attrs().Name]; found {
-				continue
-			}
+		if _, found := ignoreIfaceIndices[route.LinkIndex]; found {
+			continue
 		}
-		if err := check(link.Attrs().Name, route); err != nil {
+		if err := check(route); err != nil {
 			return err
 		}
 	}
 	return nil
 }

-func CheckRouteExists(ifaceName string, dest net.IP) bool {
-	found := false
-	forEachRoute(map[string]struct{}{}, func(name string, route netlink.Route) error {
-		if name == ifaceName && route.Dst.IP.Equal(dest) {
-			found = true
-		}
-		return nil
+func AddRoute(link netlink.Link, scope netlink.Scope, dst *net.IPNet, gw net.IP) error {
+	err := netlink.RouteAdd(&netlink.Route{
+		LinkIndex: link.Attrs().Index,
+		Scope:     scope,
+		Dst:       dst,
+		Gw:        gw,
 	})
-	return found
-}
-
-func matchRoute(ifaceName string, dest net.IP) func(m syscall.NetlinkMessage) (bool, error) {
-	return func(m syscall.NetlinkMessage) (bool, error) {
-		switch m.Header.Type {
-		case syscall.RTM_NEWROUTE:
-			route, err := deserializeRoute(m.Data)
-			if err != nil {
-				return true, err
-			}
-			link, _ := netlink.LinkByIndex(route.LinkIndex)
-			if link.Attrs().Name == ifaceName && route.Dst.IP.Equal(dest) {
-				return true, nil
-			}
-		}
-		return false, nil
+	if os.IsExist(err) { // squash duplicate route errors
+		err = nil
 	}
-}
-
-// This code proposed for addition to the vishvananda/netlink library
-// deserializeRoute decodes a binary netlink message into a Route struct
-func deserializeRoute(m []byte) (netlink.Route, error) {
-	route := netlink.Route{}
-	msg := nl.DeserializeRtMsg(m)
-	attrs, err := nl.ParseRouteAttr(m[msg.Len():])
-	if err != nil {
-		return route, err
-	}
-	route.Scope = netlink.Scope(msg.Scope)
-
-	native := nl.NativeEndian()
-	for _, attr := range attrs {
-		switch attr.Attr.Type {
-		case syscall.RTA_GATEWAY:
-			route.Gw = net.IP(attr.Value)
-		case syscall.RTA_PREFSRC:
-			route.Src = net.IP(attr.Value)
-		case syscall.RTA_DST:
-			route.Dst = &net.IPNet{
-				IP:   attr.Value,
-				Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
-			}
-		case syscall.RTA_OIF:
-			routeIndex := int(native.Uint32(attr.Value[0:4]))
-			route.LinkIndex = routeIndex
-		}
-	}
-	return route, nil
+	return err
 }
@@ -0,0 +1,204 @@
+package net
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/j-keck/arping"
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+
+	"github.com/weaveworks/weave/common/odp"
+)
+
+// create and attach a veth to the Weave bridge
+func CreateAndAttachVeth(name, peerName, bridgeName string, mtu int, keepTXOn bool, init func(peer netlink.Link) error) (*netlink.Veth, error) {
+	bridge, err := netlink.LinkByName(bridgeName)
+	if err != nil {
+		return nil, fmt.Errorf(`bridge "%s" not present; did you launch weave?`, bridgeName)
+	}
+
+	if mtu == 0 {
+		mtu = bridge.Attrs().MTU
+	}
+	veth := &netlink.Veth{
+		LinkAttrs: netlink.LinkAttrs{
+			Name: name,
+			MTU:  mtu},
+		PeerName: peerName,
+	}
+	if err := netlink.LinkAdd(veth); err != nil {
+		return nil, fmt.Errorf(`could not create veth pair %s-%s: %s`, name, peerName, err)
+	}
+
+	cleanup := func(format string, a ...interface{}) (*netlink.Veth, error) {
+		netlink.LinkDel(veth)
+		return nil, fmt.Errorf(format, a...)
+	}
+
+	switch bridgeType := DetectBridgeType(bridgeName, DatapathName); bridgeType {
+	case Bridge, BridgedFastdp:
+		if err := netlink.LinkSetMasterByIndex(veth, bridge.Attrs().Index); err != nil {
+			return cleanup(`unable to set master of %s: %s`, name, err)
+		}
+		if bridgeType == Bridge && !keepTXOn {
+			if err := EthtoolTXOff(peerName); err != nil {
+				return cleanup(`unable to set tx off on %q: %s`, peerName, err)
+			}
+		}
+	case Fastdp:
+		if err := odp.AddDatapathInterface(bridgeName, name); err != nil {
+			return cleanup(`failed to attach %s to device "%s": %s`, name, bridgeName, err)
+		}
+	default:
+		return cleanup(`invalid bridge configuration`)
+	}
+
+	if init != nil {
+		peer, err := netlink.LinkByName(peerName)
+		if err != nil {
+			return cleanup("unable to find peer veth %s: %s", peerName, err)
+		}
+		if err := init(peer); err != nil {
+			return cleanup("initializing veth: %s", err)
+		}
+	}
+
+	if err := netlink.LinkSetUp(veth); err != nil {
+		return cleanup("unable to bring veth up: %s", err)
+	}
+
+	return veth, nil
+}
+
+func AddAddresses(link netlink.Link, cidrs []*net.IPNet) (newAddrs []*net.IPNet, err error) {
+	existingAddrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get IP address for %q: %v", link.Attrs().Name, err)
+	}
+	for _, ipnet := range cidrs {
+		if contains(existingAddrs, ipnet) {
+			continue
+		}
+		if err := netlink.AddrAdd(link, &netlink.Addr{IPNet: ipnet}); err != nil {
+			return nil, fmt.Errorf("failed to add IP address to %q: %v", link.Attrs().Name, err)
+		}
+		newAddrs = append(newAddrs, ipnet)
+	}
+	return newAddrs, nil
+}
+
+func contains(addrs []netlink.Addr, addr *net.IPNet) bool {
+	for _, x := range addrs {
+		if addr.IP.Equal(x.IPNet.IP) {
+			return true
+		}
+	}
+	return false
+}
+
+const (
+	VethName   = "ethwe"        // name inside container namespace
+	vethPrefix = "v" + VethName // starts with "veth" to suppress UI notifications
+)
+
+func interfaceExistsInNamespace(ns netns.NsHandle, ifName string) bool {
+	err := WithNetNSUnsafe(ns, func() error {
+		_, err := netlink.LinkByName(ifName)
+		return err
+	})
+	return err == nil
+}
+
+func AttachContainer(ns netns.NsHandle, id, ifName, bridgeName string, mtu int, withMulticastRoute bool, cidrs []*net.IPNet, keepTXOn bool) error {
+	if !interfaceExistsInNamespace(ns, ifName) {
+		maxIDLen := IFNAMSIZ - 1 - len(vethPrefix+"pl")
+		if len(id) > maxIDLen {
+			id = id[:maxIDLen] // trim passed ID if too long
+		}
+		name, peerName := vethPrefix+"pl"+id, vethPrefix+"pg"+id
+		_, err := CreateAndAttachVeth(name, peerName, bridgeName, mtu, keepTXOn, func(veth netlink.Link) error {
+			if err := netlink.LinkSetNsFd(veth, int(ns)); err != nil {
+				return fmt.Errorf("failed to move veth to container netns: %s", err)
+			}
+			if err := WithNetNSUnsafe(ns, func() error {
+				if err := netlink.LinkSetName(veth, ifName); err != nil {
+					return err
+				}
+				if err := ConfigureARPCache(ifName); err != nil {
+					return err
+				}
+				return nil
+			}); err != nil {
+				return fmt.Errorf("error setting up interface: %s", err)
+			}
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+	}
+
+	if err := WithNetNSLinkUnsafe(ns, ifName, func(veth netlink.Link) error {
+		newAddresses, err := AddAddresses(veth, cidrs)
+		if err != nil {
+			return err
+		}
+		if err := netlink.LinkSetUp(veth); err != nil {
+			return err
+		}
+		for _, ipnet := range newAddresses {
+			// If we don't wait for a bit here, we see the arp fail to reach the bridge.
+			time.Sleep(1 * time.Millisecond)
+			arping.GratuitousArpOverIfaceByName(ipnet.IP, ifName)
+		}
+		if withMulticastRoute {
+			/* Route multicast packets across the weave network.
+			This must come last in 'attach'. If you change this, change weavewait to match.
+
+			TODO: Add the MTU lock to prevent PMTU discovery for multicast
+			destinations. Without that, the kernel sets the DF flag on
+			multicast packets. Since RFC1122 prohibits sending of ICMP
+			errors for packets with multicast destinations, that causes
+			packets larger than the PMTU to be dropped silently.  */
+
+			_, multicast, _ := net.ParseCIDR("224.0.0.0/4")
+			if err := AddRoute(veth, netlink.SCOPE_LINK, multicast, nil); err != nil {
+				return err
+			}
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func DetachContainer(ns netns.NsHandle, id, ifName string, cidrs []*net.IPNet) error {
+	return WithNetNSLinkUnsafe(ns, ifName, func(veth netlink.Link) error {
+		existingAddrs, err := netlink.AddrList(veth, netlink.FAMILY_V4)
+		if err != nil {
+			return fmt.Errorf("failed to get IP address for %q: %v", veth.Attrs().Name, err)
+		}
+		for _, ipnet := range cidrs {
+			if !contains(existingAddrs, ipnet) {
+				continue
+			}
+			if err := netlink.AddrDel(veth, &netlink.Addr{IPNet: ipnet}); err != nil {
+				return fmt.Errorf("failed to remove IP address from %q: %v", veth.Attrs().Name, err)
+			}
+		}
+		addrs, err := netlink.AddrList(veth, netlink.FAMILY_V4)
+		if err != nil {
+			return fmt.Errorf("failed to get IP address for %q: %v", veth.Attrs().Name, err)
+		}
+		if len(addrs) == 0 { // all addresses gone: remove the interface
+			if err := netlink.LinkDel(veth); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
@@ -0,0 +1,14 @@
+# Weave network driver extension for Docker and Kubernetes
+
+This directory implements both a 
+[Docker plugin](http://docs.docker.com/engine/extend/plugin_api/) to
+integrate [Weave Net](http://weave.works/net/) with Docker, and a 
+[Container Network Interface (CNI) plugin](https://github.com/appc/cni#cni---the-container-network-interface),
+to integrate Weave Net with [Kubernetes](http://kubernetes.io/).
+
+The Docker plugin runs automatically when you `weave launch`, provided your
+Docker daemon is version 1.9 or newer.
+
+More detail on the Docker plugin [here](https://www.weave.works/docs/net/latest/plugin/).
+
+More detail on the CNI plugin [here](https://www.weave.works/docs/net/latest/cni-plugin/).
@@ -0,0 +1,80 @@
+package ipamplugin
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+
+	"github.com/appc/cni/pkg/skel"
+	"github.com/appc/cni/pkg/types"
+)
+
+func (i *Ipam) CmdAdd(args *skel.CmdArgs) error {
+	result, err := i.Allocate(args)
+	if err != nil {
+		return err
+	}
+	return result.Print()
+}
+
+func (i *Ipam) Allocate(args *skel.CmdArgs) (*types.Result, error) {
+	// extract the things we care about
+	conf, err := loadIPAMConf(args.StdinData)
+	if err != nil {
+		return nil, err
+	}
+	if conf == nil {
+		conf = &ipamConf{}
+	}
+	containerID := args.ContainerID
+	if containerID == "" {
+		return nil, fmt.Errorf("Weave CNI Allocate: blank container name")
+	}
+	var ipnet *net.IPNet
+
+	if conf.Subnet == "" {
+		ipnet, err = i.weave.AllocateIP(containerID)
+	} else {
+		var subnet *net.IPNet
+		subnet, err = types.ParseCIDR(conf.Subnet)
+		if err != nil {
+			return nil, fmt.Errorf("subnet given in config, but not parseable: %s", err)
+		}
+		ipnet, err = i.weave.AllocateIPInSubnet(containerID, subnet)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	result := &types.Result{
+		IP4: &types.IPConfig{
+			IP:      *ipnet,
+			Gateway: conf.Gateway,
+			Routes:  conf.Routes,
+		},
+	}
+	return result, nil
+}
+
+func (i *Ipam) CmdDel(args *skel.CmdArgs) error {
+	return i.Release(args)
+}
+
+func (i *Ipam) Release(args *skel.CmdArgs) error {
+	return i.weave.ReleaseIPsFor(args.ContainerID)
+}
+
+type ipamConf struct {
+	Subnet  string        `json:"subnet,omitempty"`
+	Gateway net.IP        `json:"gateway,omitempty"`
+	Routes  []types.Route `json:"routes"`
+}
+
+type netConf struct {
+	IPAM *ipamConf `json:"ipam"`
+}
+
+func loadIPAMConf(stdinData []byte) (*ipamConf, error) {
+	var conf netConf
+	return conf.IPAM, json.Unmarshal(stdinData, &conf)
+}
@@ -0,0 +1,131 @@
+package ipamplugin
+
+import (
+	"fmt"
+	"net"
+	"strings"
+
+	"github.com/docker/libnetwork/discoverapi"
+	"github.com/docker/libnetwork/netlabel"
+	"github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+)
+
+type Ipam struct {
+	weave *api.Client
+}
+
+func NewIpam(weave *api.Client) *Ipam {
+	return &Ipam{weave: weave}
+}
+
+func (i *Ipam) GetDefaultAddressSpaces() (string, string, error) {
+	i.logReq("GetDefaultAddressSpaces")
+	return "weavelocal", "weaveglobal", nil
+}
+
+func (i *Ipam) RequestPool(addressSpace, pool, subPool string, options map[string]string, v6 bool) (poolname string, subnet *net.IPNet, data map[string]string, err error) {
+	i.logReq("RequestPool", addressSpace, pool, subPool, options)
+	defer func() { i.logRes("RequestPool", err, poolname, subnet, data) }()
+	if pool == "" {
+		subnet, err = i.weave.DefaultSubnet()
+	} else {
+		_, subnet, err = net.ParseCIDR(pool)
+	}
+	if err != nil {
+		return
+	}
+	iprange := subnet
+	if subPool != "" {
+		if _, iprange, err = net.ParseCIDR(subPool); err != nil {
+			return
+		}
+	}
+	// Cunningly-constructed pool "name" which gives us what we need later
+	poolname = strings.Join([]string{"weave", subnet.String(), iprange.String()}, "-")
+	// Pass back a fake "gateway address"; we don't actually use it,
+	// so just give the network address.
+	data = map[string]string{netlabel.Gateway: subnet.String()}
+	return
+}
+
+func (i *Ipam) ReleasePool(poolID string) error {
+	i.logReq("ReleasePool", poolID)
+	return nil
+}
+
+func splitPoolID(poolID string) (subnet, iprange *net.IPNet, err error) {
+	parts := strings.Split(poolID, "-")
+	if len(parts) != 3 || parts[0] != "weave" {
+		err = fmt.Errorf("Unrecognized pool ID: %s", poolID)
+		return
+	}
+	if _, subnet, err = net.ParseCIDR(parts[1]); err != nil {
+		return
+	}
+	if _, iprange, err = net.ParseCIDR(parts[2]); err != nil {
+		return
+	}
+	return
+}
+
+func (i *Ipam) RequestAddress(poolID string, address net.IP, options map[string]string) (ip *net.IPNet, _ map[string]string, err error) {
+	i.logReq("RequestAddress", poolID, address, options)
+	defer func() { i.logRes("RequestAddress", err, ip) }()
+	// If we pass magic string "_" to weave IPAM it stores the address under its own string
+	if poolID == "weavepool" { // old-style
+		ip, err = i.weave.AllocateIP("_")
+		return
+	}
+	subnet, iprange, err := splitPoolID(poolID)
+	if err != nil {
+		return
+	}
+	if address != nil { // try to claim specific address requested
+		ip = &net.IPNet{IP: address, Mask: subnet.Mask}
+		if err = i.weave.ClaimIP("_", ip); err != nil {
+			return
+		}
+	} else {
+		// We are lying slightly to IPAM here: the range is not a subnet
+		if ip, err = i.weave.AllocateIPInSubnet("_", iprange); err != nil {
+			return
+		}
+		ip.Mask = subnet.Mask // fix up the subnet we lied about
+	}
+	return
+}
+
+func (i *Ipam) ReleaseAddress(poolID string, address net.IP) error {
+	i.logReq("ReleaseAddress", poolID, address)
+	if subnet, _, err := splitPoolID(poolID); err != nil {
+		return err
+	} else if address.Equal(subnet.IP) { // is it the gateway address we faked earlier?
+		return nil
+	}
+	return i.weave.ReleaseIPsFor(address.String())
+}
+
+// Functions required by ipamapi "contract" but not actually used.
+
+func (i *Ipam) DiscoverNew(discoverapi.DiscoveryType, interface{}) error {
+	return nil
+}
+
+func (i *Ipam) DiscoverDelete(discoverapi.DiscoveryType, interface{}) error {
+	return nil
+}
+
+// logging
+
+func (i *Ipam) logReq(fun string, args ...interface{}) {
+	common.Log.Infoln(append([]interface{}{fmt.Sprintf("[ipam] %s", fun)}, args...)...)
+}
+
+func (i *Ipam) logRes(fun string, err error, args ...interface{}) {
+	if err == nil {
+		common.Log.Debugln(append([]interface{}{fmt.Sprintf("[ipam] %s result", fun)}, args...)...)
+		return
+	}
+	common.Log.Errorf("[ipam] %s: %s", fun, err)
+}
@@ -0,0 +1,218 @@
+package plugin
+
+import (
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"net"
+
+	"github.com/appc/cni/pkg/ipam"
+	"github.com/appc/cni/pkg/skel"
+	"github.com/appc/cni/pkg/types"
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netns"
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	weavenet "github.com/weaveworks/weave/net"
+	ipamplugin "github.com/weaveworks/weave/plugin/ipam"
+)
+
+var (
+	zeroNetwork = net.IPNet{IP: net.IPv4zero, Mask: net.IPv4Mask(0, 0, 0, 0)}
+	mask32      = net.IPv4Mask(0xff, 0xff, 0xff, 0xff)
+)
+
+type CNIPlugin struct {
+	weave *weaveapi.Client
+}
+
+func NewCNIPlugin(weave *weaveapi.Client) *CNIPlugin {
+	return &CNIPlugin{weave: weave}
+}
+
+func loadNetConf(bytes []byte) (*NetConf, error) {
+	n := &NetConf{
+		BrName: weavenet.WeaveBridgeName,
+	}
+	if err := json.Unmarshal(bytes, n); err != nil {
+		return nil, fmt.Errorf("failed to load netconf: %v", err)
+	}
+	return n, nil
+}
+
+func (c *CNIPlugin) getIP(ipamType string, args *skel.CmdArgs) (result *types.Result, err error) {
+	// Default IPAM is Weave's own
+	if ipamType == "" {
+		result, err = ipamplugin.NewIpam(c.weave).Allocate(args)
+	} else {
+		result, err = ipam.ExecAdd(ipamType, args.StdinData)
+	}
+	if err == nil && result.IP4 == nil {
+		return nil, fmt.Errorf("IPAM plugin failed to allocate IP address")
+	}
+	return result, err
+}
+
+func (c *CNIPlugin) CmdAdd(args *skel.CmdArgs) error {
+	conf, err := loadNetConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+
+	if conf.IsGW {
+		return fmt.Errorf("Gateway functionality not supported")
+	}
+	if conf.IPMasq {
+		return fmt.Errorf("IP Masquerading functionality not supported")
+	}
+
+	result, err := c.getIP(conf.IPAM.Type, args)
+	if err != nil {
+		return fmt.Errorf("unable to allocate IP address: %s", err)
+	}
+
+	// If config says nothing about routes or gateway, default one will be via the bridge
+	if result.IP4.Routes == nil && result.IP4.Gateway == nil {
+		bridgeIP, err := findBridgeIP(conf.BrName, result.IP4.IP)
+		if err == errBridgeNoIP {
+			bridgeArgs := *args
+			bridgeArgs.ContainerID = "weave:expose"
+			bridgeIPResult, err := c.getIP(conf.IPAM.Type, &bridgeArgs)
+			if err != nil {
+				return fmt.Errorf("unable to allocate IP address for bridge: %s", err)
+			}
+			if err := assignBridgeIP(conf.BrName, bridgeIPResult.IP4.IP); err != nil {
+				return fmt.Errorf("unable to assign IP address to bridge: %s", err)
+			}
+			bridgeIP = bridgeIPResult.IP4.IP.IP
+		} else if err != nil {
+			return err
+		}
+		result.IP4.Gateway = bridgeIP
+	}
+
+	ns, err := netns.GetFromPath(args.Netns)
+	if err != nil {
+		return err
+	}
+	defer ns.Close()
+
+	id := args.ContainerID
+	if len(id) < 5 {
+		data := make([]byte, 5)
+		_, err := rand.Reader.Read(data)
+		if err != nil {
+			return err
+		}
+		id = fmt.Sprintf("%x", data)
+	}
+
+	if err := weavenet.AttachContainer(ns, id, args.IfName, conf.BrName, conf.MTU, false, []*net.IPNet{&result.IP4.IP}, false); err != nil {
+		return err
+	}
+	if err := weavenet.WithNetNSLinkUnsafe(ns, args.IfName, func(link netlink.Link) error {
+		return setupRoutes(link, args.IfName, result.IP4.IP, result.IP4.Gateway, result.IP4.Routes)
+	}); err != nil {
+		return fmt.Errorf("error setting up routes: %s", err)
+	}
+
+	result.DNS = conf.DNS
+	return result.Print()
+}
+
+func setupRoutes(link netlink.Link, name string, ipnet net.IPNet, gw net.IP, routes []types.Route) error {
+	var err error
+	if routes == nil { // If config says nothing about routes, add a default one
+		if !ipnet.Contains(gw) {
+			// The bridge IP is not on the same subnet; add a specific route to it
+			gw32 := &net.IPNet{IP: gw, Mask: mask32}
+			if err = weavenet.AddRoute(link, netlink.SCOPE_LINK, gw32, nil); err != nil {
+				return err
+			}
+		}
+		routes = []types.Route{{Dst: zeroNetwork}}
+	}
+	for _, r := range routes {
+		if r.GW != nil {
+			err = weavenet.AddRoute(link, netlink.SCOPE_UNIVERSE, &r.Dst, r.GW)
+		} else {
+			err = weavenet.AddRoute(link, netlink.SCOPE_UNIVERSE, &r.Dst, gw)
+		}
+		if err != nil {
+			return fmt.Errorf("failed to add route '%v via %v dev %v': %v", r.Dst, gw, name, err)
+		}
+	}
+	return nil
+}
+
+func assignBridgeIP(bridgeName string, ipnet net.IPNet) error {
+	link, err := netlink.LinkByName(bridgeName)
+	if err != nil {
+		return err
+	}
+	if err := netlink.AddrAdd(link, &netlink.Addr{IPNet: &ipnet}); err != nil {
+		return fmt.Errorf("failed to add IP address to %q: %v", bridgeName, err)
+	}
+	return nil
+}
+
+var errBridgeNoIP = fmt.Errorf("Bridge has no IP address")
+
+func findBridgeIP(bridgeName string, subnet net.IPNet) (net.IP, error) {
+	netdev, err := common.GetBridgeNetDev(bridgeName)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to get netdev for %q bridge: %s", bridgeName, err)
+	}
+	if len(netdev.CIDRs) == 0 {
+		return nil, errBridgeNoIP
+	}
+	for _, cidr := range netdev.CIDRs {
+		if subnet.Contains(cidr.IP) {
+			return cidr.IP, nil
+		}
+	}
+	// None in the required subnet; just return the first one
+	return netdev.CIDRs[0].IP, nil
+}
+
+func (c *CNIPlugin) CmdDel(args *skel.CmdArgs) error {
+	conf, err := loadNetConf(args.StdinData)
+	if err != nil {
+		return err
+	}
+
+	ns, err := netns.GetFromPath(args.Netns)
+	if err != nil {
+		return err
+	}
+	defer ns.Close()
+	err = weavenet.WithNetNSUnsafe(ns, func() error {
+		link, err := netlink.LinkByName(args.IfName)
+		if err != nil {
+			return err
+		}
+		return netlink.LinkDel(link)
+	})
+	if err != nil {
+		return fmt.Errorf("error removing interface: %s", err)
+	}
+
+	// Default IPAM is Weave's own
+	if conf.IPAM.Type == "" {
+		err = ipamplugin.NewIpam(c.weave).Release(args)
+	} else {
+		err = ipam.ExecDel(conf.IPAM.Type, args.StdinData)
+	}
+	if err != nil {
+		return fmt.Errorf("unable to release IP address: %s", err)
+	}
+	return nil
+}
+
+type NetConf struct {
+	types.NetConf
+	BrName string `json:"bridge"`
+	IsGW   bool   `json:"isGateway"`
+	IPMasq bool   `json:"ipMasq"`
+	MTU    int    `json:"mtu"`
+}
@@ -0,0 +1,238 @@
+package plugin
+
+import (
+	"fmt"
+	"strconv"
+	"sync"
+
+	"github.com/docker/libnetwork/drivers/remote/api"
+	"github.com/docker/libnetwork/netlabel"
+	"github.com/docker/libnetwork/types"
+
+	"github.com/vishvananda/netlink"
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common/docker"
+	weavenet "github.com/weaveworks/weave/net"
+	"github.com/weaveworks/weave/plugin/skel"
+)
+
+const (
+	MulticastOption = "works.weave.multicast"
+)
+
+type network struct {
+	isOurs            bool
+	hasMulticastRoute bool
+}
+
+type driver struct {
+	name   string
+	scope  string
+	docker *docker.Client
+	sync.RWMutex
+	networks map[string]network
+}
+
+func New(client *docker.Client, weave *weaveapi.Client, name, scope string) (skel.Driver, error) {
+	driver := &driver{
+		name:     name,
+		scope:    scope,
+		docker:   client,
+		networks: make(map[string]network),
+	}
+
+	_, err := NewWatcher(client, weave, driver)
+	if err != nil {
+		return nil, err
+	}
+	return driver, nil
+}
+
+// === protocol handlers
+
+func (driver *driver) GetCapabilities() (*api.GetCapabilityResponse, error) {
+	driver.logReq("GetCapabilities", nil, "")
+	var caps = &api.GetCapabilityResponse{
+		Scope: driver.scope,
+	}
+	driver.logRes("GetCapabilities", caps)
+	return caps, nil
+}
+
+func (driver *driver) CreateNetwork(create *api.CreateNetworkRequest) error {
+	driver.logReq("CreateNetwork", create, create.NetworkID)
+	_, err := driver.setupNetworkInfo(create.NetworkID, true, stringOptions(create))
+	return err
+}
+
+// Deal with excessively-generic way the options get decoded from JSON
+func stringOptions(create *api.CreateNetworkRequest) map[string]string {
+	if create.Options != nil {
+		if data, found := create.Options[netlabel.GenericData]; found {
+			if options, ok := data.(map[string]interface{}); ok {
+				out := make(map[string]string, len(options))
+				for key, value := range options {
+					if str, ok := value.(string); ok {
+						out[key] = str
+					}
+				}
+				return out
+			}
+		}
+	}
+	return nil
+}
+
+func (driver *driver) DeleteNetwork(delreq *api.DeleteNetworkRequest) error {
+	driver.logReq("DeleteNetwork", delreq, delreq.NetworkID)
+	driver.Lock()
+	delete(driver.networks, delreq.NetworkID)
+	driver.Unlock()
+	return nil
+}
+
+func (driver *driver) CreateEndpoint(create *api.CreateEndpointRequest) (*api.CreateEndpointResponse, error) {
+	driver.logReq("CreateEndpoint", create, create.EndpointID)
+
+	if create.Interface == nil {
+		return nil, driver.error("CreateEndpoint", "Not supported: creating an interface from within CreateEndpoint")
+	}
+	resp := &api.CreateEndpointResponse{}
+
+	driver.logRes("CreateEndpoint", resp)
+	return resp, nil
+}
+
+func (driver *driver) DeleteEndpoint(deleteReq *api.DeleteEndpointRequest) error {
+	driver.logReq("DeleteEndpoint", deleteReq, deleteReq.EndpointID)
+	return nil
+}
+
+func (driver *driver) EndpointInfo(req *api.EndpointInfoRequest) (*api.EndpointInfoResponse, error) {
+	driver.logReq("EndpointInfo", req, req.EndpointID)
+	return &api.EndpointInfoResponse{Value: map[string]interface{}{}}, nil
+}
+
+func (driver *driver) JoinEndpoint(j *api.JoinRequest) (*api.JoinResponse, error) {
+	driver.logReq("JoinEndpoint", j, fmt.Sprintf("%s:%s to %s", j.NetworkID, j.EndpointID, j.SandboxKey))
+
+	network, err := driver.findNetworkInfo(j.NetworkID)
+	if err != nil {
+		return nil, driver.error("JoinEndpoint", "unable to find network info: %s", err)
+	}
+
+	name, peerName := vethPair(j.EndpointID)
+	if _, err := weavenet.CreateAndAttachVeth(name, peerName, weavenet.WeaveBridgeName, 0, false, nil); err != nil {
+		return nil, driver.error("JoinEndpoint", "%s", err)
+	}
+
+	response := &api.JoinResponse{
+		InterfaceName: &api.InterfaceName{
+			SrcName:   peerName,
+			DstPrefix: weavenet.VethName,
+		},
+	}
+	if network.hasMulticastRoute {
+		multicastRoute := api.StaticRoute{
+			Destination: "224.0.0.0/4",
+			RouteType:   types.CONNECTED,
+		}
+		response.StaticRoutes = append(response.StaticRoutes, multicastRoute)
+	}
+	driver.logRes("JoinEndpoint", response)
+	return response, nil
+}
+
+func (driver *driver) findNetworkInfo(id string) (network, error) {
+	driver.Lock()
+	network, found := driver.networks[id]
+	driver.Unlock()
+	if found {
+		return network, nil
+	}
+	info, err := driver.docker.NetworkInfo(id)
+	if err != nil {
+		return network, err
+	}
+	return driver.setupNetworkInfo(id, info.Driver == driver.name, info.Options)
+}
+
+func (driver *driver) setupNetworkInfo(id string, isOurs bool, options map[string]string) (network, error) {
+	network := network{isOurs: isOurs}
+	if isOurs {
+		for key, value := range options {
+			switch key {
+			case MulticastOption:
+				if value == "" { // interpret "--opt works.weave.multicast" as "turn it on"
+					network.hasMulticastRoute = true
+				} else {
+					var err error
+					if network.hasMulticastRoute, err = strconv.ParseBool(value); err != nil {
+						return network, fmt.Errorf("unrecognized value %q for option %s", value, key)
+					}
+
+				}
+			default:
+				driver.warn("setupNetworkInfo", "unrecognized option: %s", key)
+			}
+		}
+	}
+	driver.Lock()
+	driver.networks[id] = network
+	driver.Unlock()
+	return network, nil
+}
+
+func (driver *driver) LeaveEndpoint(leave *api.LeaveRequest) error {
+	driver.logReq("LeaveEndpoint", leave, fmt.Sprintf("%s:%s", leave.NetworkID, leave.EndpointID))
+
+	name, _ := vethPair(leave.EndpointID)
+	veth := &netlink.Veth{LinkAttrs: netlink.LinkAttrs{Name: name}}
+	if err := netlink.LinkDel(veth); err != nil {
+		driver.warn("LeaveEndpoint", "unable to delete veth: %s", err)
+	}
+	return nil
+}
+
+func (driver *driver) DiscoverNew(disco *api.DiscoveryNotification) error {
+	driver.logReq("DiscoverNew", disco, "")
+	return nil
+}
+
+func (driver *driver) DiscoverDelete(disco *api.DiscoveryNotification) error {
+	driver.logReq("DiscoverDelete", disco, "")
+	return nil
+}
+
+func vethPair(id string) (string, string) {
+	return "vethwl" + id[:5], "vethwg" + id[:5]
+}
+
+// logging
+
+func (driver *driver) logReq(fun string, req interface{}, short string) {
+	driver.log(common.Log.Debugf, " %+v", fun, req)
+	common.Log.Infof("[net] %s %s", fun, short)
+}
+
+func (driver *driver) logRes(fun string, res interface{}) {
+	driver.log(common.Log.Debugf, " %+v", fun, res)
+}
+
+func (driver *driver) warn(fun string, format string, a ...interface{}) {
+	driver.log(common.Log.Warnf, ": "+format, fun, a...)
+}
+
+func (driver *driver) debug(fun string, format string, a ...interface{}) {
+	driver.log(common.Log.Debugf, ": "+format, fun, a...)
+}
+
+func (driver *driver) error(fun string, format string, a ...interface{}) error {
+	driver.log(common.Log.Errorf, ": "+format, fun, a...)
+	return fmt.Errorf(format, a...)
+}
+
+func (driver *driver) log(f func(string, ...interface{}), format string, fun string, a ...interface{}) {
+	f("[net] %s"+format, append([]interface{}{fun}, a...)...)
+}
@@ -0,0 +1,61 @@
+package plugin
+
+import (
+	"fmt"
+
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common/docker"
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+const (
+	WeaveDomain = "weave.local"
+)
+
+type watcher struct {
+	client *docker.Client
+	weave  *weaveapi.Client
+	driver *driver
+}
+
+type Watcher interface {
+}
+
+func NewWatcher(client *docker.Client, weave *weaveapi.Client, driver *driver) (Watcher, error) {
+	w := &watcher{client: client, weave: weave, driver: driver}
+	return w, client.AddObserver(w)
+}
+
+func (w *watcher) ContainerStarted(id string) {
+	w.driver.debug("ContainerStarted", "%s", id)
+	info, err := w.client.InspectContainer(id)
+	if err != nil {
+		w.driver.warn("ContainerStarted", "error inspecting container %s: %s", id, err)
+		return
+	}
+	// check that it's on our network
+	for _, net := range info.NetworkSettings.Networks {
+		network, err := w.driver.findNetworkInfo(net.NetworkID)
+		if err != nil {
+			w.driver.warn("ContainerStarted", "unable to find network %s info: %s", net.NetworkID, err)
+			continue
+		}
+		if network.isOurs {
+			fqdn := fmt.Sprintf("%s.%s", info.Config.Hostname, info.Config.Domainname)
+			if err := w.weave.RegisterWithDNS(id, fqdn, net.IPAddress); err != nil {
+				w.driver.warn("ContainerStarted", "unable to register %s with weaveDNS: %s", id, err)
+			}
+			if err := common.ConfigureARPforVeths(info.State.Pid, weavenet.VethName); err != nil {
+				w.driver.warn("ContainerStarted", "unable to configure interfaces: %s", err)
+			}
+		}
+	}
+}
+
+func (w *watcher) ContainerDied(id string) {
+	// don't need to do this as WeaveDNS removes names on container died anyway
+	// (note by the time we get this event we can't see the EndpointID)
+}
+
+func (w *watcher) ContainerDestroyed(id string) {}
@@ -0,0 +1,299 @@
+package skel
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+
+	"github.com/gorilla/mux"
+
+	"github.com/docker/libnetwork/drivers/remote/api"
+	"github.com/docker/libnetwork/ipamapi"
+	iapi "github.com/docker/libnetwork/ipams/remote/api"
+)
+
+const (
+	networkReceiver = "NetworkDriver"
+	ipamReceiver    = ipamapi.PluginEndpointType
+)
+
+type Driver interface {
+	GetCapabilities() (*api.GetCapabilityResponse, error)
+	CreateNetwork(create *api.CreateNetworkRequest) error
+	DeleteNetwork(delete *api.DeleteNetworkRequest) error
+	CreateEndpoint(create *api.CreateEndpointRequest) (*api.CreateEndpointResponse, error)
+	DeleteEndpoint(delete *api.DeleteEndpointRequest) error
+	EndpointInfo(req *api.EndpointInfoRequest) (*api.EndpointInfoResponse, error)
+	JoinEndpoint(j *api.JoinRequest) (response *api.JoinResponse, error error)
+	LeaveEndpoint(leave *api.LeaveRequest) error
+	DiscoverNew(discover *api.DiscoveryNotification) error
+	DiscoverDelete(delete *api.DiscoveryNotification) error
+}
+
+type listener struct {
+	d Driver
+	i ipamapi.Ipam
+}
+
+func Listen(socket net.Listener, driver Driver, ipamDriver ipamapi.Ipam) error {
+	router := mux.NewRouter()
+	router.NotFoundHandler = http.HandlerFunc(notFound)
+
+	listener := &listener{driver, ipamDriver}
+
+	router.Methods("POST").Path("/Plugin.Activate").HandlerFunc(listener.handshake)
+
+	handleMethod := func(receiver, method string, h http.HandlerFunc) {
+		router.Methods("POST").Path(fmt.Sprintf("/%s.%s", receiver, method)).HandlerFunc(h)
+	}
+
+	handleMethod(networkReceiver, "GetCapabilities", listener.getCapabilities)
+
+	if driver != nil {
+		handleMethod(networkReceiver, "CreateNetwork", listener.createNetwork)
+		handleMethod(networkReceiver, "DeleteNetwork", listener.deleteNetwork)
+		handleMethod(networkReceiver, "CreateEndpoint", listener.createEndpoint)
+		handleMethod(networkReceiver, "DeleteEndpoint", listener.deleteEndpoint)
+		handleMethod(networkReceiver, "EndpointOperInfo", listener.infoEndpoint)
+		handleMethod(networkReceiver, "Join", listener.joinEndpoint)
+		handleMethod(networkReceiver, "Leave", listener.leaveEndpoint)
+	}
+
+	if ipamDriver != nil {
+		handleMethod(ipamReceiver, "GetDefaultAddressSpaces", listener.getDefaultAddressSpaces)
+		handleMethod(ipamReceiver, "RequestPool", listener.requestPool)
+		handleMethod(ipamReceiver, "ReleasePool", listener.releasePool)
+		handleMethod(ipamReceiver, "RequestAddress", listener.requestAddress)
+		handleMethod(ipamReceiver, "ReleaseAddress", listener.releaseAddress)
+	}
+
+	return http.Serve(socket, router)
+}
+
+func decode(w http.ResponseWriter, r *http.Request, v interface{}) error {
+	err := json.NewDecoder(r.Body).Decode(v)
+	if err != nil {
+		sendError(w, "Unable to decode JSON payload: "+err.Error(), http.StatusBadRequest)
+	}
+	return err
+}
+
+// === protocol handlers
+
+type handshakeResp struct {
+	Implements []string
+}
+
+func (listener *listener) handshake(w http.ResponseWriter, r *http.Request) {
+	var resp handshakeResp
+	if listener.d != nil {
+		resp.Implements = append(resp.Implements, "NetworkDriver")
+	}
+	if listener.i != nil {
+		resp.Implements = append(resp.Implements, "IpamDriver")
+	}
+	err := json.NewEncoder(w).Encode(&resp)
+	if err != nil {
+		sendError(w, "encode error", http.StatusInternalServerError)
+		return
+	}
+}
+
+func (listener *listener) getCapabilities(w http.ResponseWriter, r *http.Request) {
+	caps, err := listener.d.GetCapabilities()
+	objectOrErrorResponse(w, caps, err)
+}
+
+func (listener *listener) createNetwork(w http.ResponseWriter, r *http.Request) {
+	var create api.CreateNetworkRequest
+	err := json.NewDecoder(r.Body).Decode(&create)
+	if err != nil {
+		sendError(w, "Unable to decode JSON payload: "+err.Error(), http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.CreateNetwork(&create))
+}
+
+func (listener *listener) deleteNetwork(w http.ResponseWriter, r *http.Request) {
+	var delete api.DeleteNetworkRequest
+	if err := json.NewDecoder(r.Body).Decode(&delete); err != nil {
+		sendError(w, "Unable to decode JSON payload: "+err.Error(), http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.DeleteNetwork(&delete))
+}
+
+func (listener *listener) createEndpoint(w http.ResponseWriter, r *http.Request) {
+	var create api.CreateEndpointRequest
+	if err := json.NewDecoder(r.Body).Decode(&create); err != nil {
+		sendError(w, "unable to decode JSON payload: "+err.Error(), http.StatusBadRequest)
+		return
+	}
+	res, err := listener.d.CreateEndpoint(&create)
+	objectOrErrorResponse(w, res, err)
+}
+
+func (listener *listener) deleteEndpoint(w http.ResponseWriter, r *http.Request) {
+	var delete api.DeleteEndpointRequest
+	if err := json.NewDecoder(r.Body).Decode(&delete); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.DeleteEndpoint(&delete))
+}
+
+func (listener *listener) infoEndpoint(w http.ResponseWriter, r *http.Request) {
+	var req api.EndpointInfoRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	info, err := listener.d.EndpointInfo(&req)
+	objectOrErrorResponse(w, info, err)
+}
+
+func (listener *listener) joinEndpoint(w http.ResponseWriter, r *http.Request) {
+	var join api.JoinRequest
+	if err := json.NewDecoder(r.Body).Decode(&join); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	res, err := listener.d.JoinEndpoint(&join)
+	objectOrErrorResponse(w, res, err)
+}
+
+func (listener *listener) leaveEndpoint(w http.ResponseWriter, r *http.Request) {
+	var l api.LeaveRequest
+	if err := json.NewDecoder(r.Body).Decode(&l); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.LeaveEndpoint(&l))
+}
+
+func (listener *listener) discoverNew(w http.ResponseWriter, r *http.Request) {
+	var disco api.DiscoveryNotification
+	if err := json.NewDecoder(r.Body).Decode(&disco); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.DiscoverNew(&disco))
+}
+
+func (listener *listener) discoverDelete(w http.ResponseWriter, r *http.Request) {
+	var disco api.DiscoveryNotification
+	if err := json.NewDecoder(r.Body).Decode(&disco); err != nil {
+		sendError(w, "Could not decode JSON encode payload", http.StatusBadRequest)
+		return
+	}
+	emptyOrErrorResponse(w, listener.d.DiscoverDelete(&disco))
+}
+
+// ===
+
+func (listener *listener) getDefaultAddressSpaces(w http.ResponseWriter, r *http.Request) {
+	local, global, err := listener.i.GetDefaultAddressSpaces()
+	response := &iapi.GetAddressSpacesResponse{
+		LocalDefaultAddressSpace:  local,
+		GlobalDefaultAddressSpace: global,
+	}
+	objectOrErrorResponse(w, response, err)
+}
+
+func (listener *listener) requestPool(w http.ResponseWriter, r *http.Request) {
+	var rq iapi.RequestPoolRequest
+	if err := decode(w, r, &rq); err != nil {
+		return
+	}
+	poolID, pool, data, err := listener.i.RequestPool(rq.AddressSpace, rq.Pool, rq.SubPool, rq.Options, rq.V6)
+	if err != nil {
+		errorResponse(w, err.Error())
+		return
+	}
+	response := &iapi.RequestPoolResponse{
+		PoolID: poolID,
+		Pool:   pool.String(),
+		Data:   data,
+	}
+	objectResponse(w, response)
+}
+
+func (listener *listener) releasePool(w http.ResponseWriter, r *http.Request) {
+	var rq iapi.ReleasePoolRequest
+	if err := decode(w, r, &rq); err != nil {
+		return
+	}
+	err := listener.i.ReleasePool(rq.PoolID)
+	emptyOrErrorResponse(w, err)
+}
+
+func (listener *listener) requestAddress(w http.ResponseWriter, r *http.Request) {
+	var rq iapi.RequestAddressRequest
+	if err := decode(w, r, &rq); err != nil {
+		return
+	}
+	address, data, err := listener.i.RequestAddress(rq.PoolID, net.ParseIP(rq.Address), rq.Options)
+	if err != nil {
+		errorResponse(w, err.Error())
+		return
+	}
+	response := &iapi.RequestAddressResponse{
+		Address: address.String(),
+		Data:    data,
+	}
+	objectResponse(w, response)
+}
+
+func (listener *listener) releaseAddress(w http.ResponseWriter, r *http.Request) {
+	var rq iapi.ReleaseAddressRequest
+	if err := decode(w, r, &rq); err != nil {
+		return
+	}
+	err := listener.i.ReleaseAddress(rq.PoolID, net.ParseIP(rq.Address))
+	emptyOrErrorResponse(w, err)
+}
+
+// ===
+
+func notFound(w http.ResponseWriter, r *http.Request) {
+	http.NotFound(w, r)
+}
+
+func sendError(w http.ResponseWriter, msg string, code int) {
+	http.Error(w, msg, code)
+}
+
+func errorResponse(w http.ResponseWriter, fmtString string, item ...interface{}) {
+	w.WriteHeader(http.StatusInternalServerError)
+	json.NewEncoder(w).Encode(map[string]string{
+		"Err": fmt.Sprintf(fmtString, item...),
+	})
+}
+
+func objectResponse(w http.ResponseWriter, obj interface{}) {
+	if err := json.NewEncoder(w).Encode(obj); err != nil {
+		sendError(w, "Could not JSON encode response", http.StatusInternalServerError)
+		return
+	}
+}
+
+func emptyResponse(w http.ResponseWriter) {
+	json.NewEncoder(w).Encode(map[string]string{})
+}
+
+func objectOrErrorResponse(w http.ResponseWriter, obj interface{}, err error) {
+	if err != nil {
+		errorResponse(w, err.Error())
+		return
+	}
+	objectResponse(w, obj)
+}
+
+func emptyOrErrorResponse(w http.ResponseWriter, err error) {
+	if err != nil {
+		errorResponse(w, err.Error())
+		return
+	}
+	emptyResponse(w)
+}
@@ -1,54 +0,0 @@
-/* netcheck: check whether a given network or address overlaps with any existing routes */
-package main
-
-import (
-	"fmt"
-	"net"
-	"os"
-
-	"github.com/docker/docker/pkg/mflag"
-	weavenet "github.com/weaveworks/weave/net"
-)
-
-func fatal(err error) {
-	fmt.Fprintln(os.Stderr, err)
-	os.Exit(1)
-}
-
-type stringList map[string]struct{}
-
-func (ss *stringList) Set(value string) error {
-	(*ss)[value] = struct{}{}
-	return nil
-}
-
-func (ss *stringList) String() string {
-	return fmt.Sprintf("%v", *ss)
-}
-
-func main() {
-	ignoreIfaceNames := make(stringList)
-
-	mflag.Var(&ignoreIfaceNames, []string{"-ignore-iface"}, "name of interface to ignore)")
-	mflag.Parse()
-
-	if len(mflag.Args()) < 1 {
-		fmt.Fprintln(os.Stderr, "usage: netcheck [--ignore-iface <iface-name>] network-cidr")
-		os.Exit(1)
-	}
-
-	cidrStr := mflag.Args()[0]
-	addr, ipnet, err := net.ParseCIDR(cidrStr)
-	if err != nil {
-		fatal(err)
-	}
-	if ipnet.IP.Equal(addr) {
-		err = weavenet.CheckNetworkFree(ipnet, ignoreIfaceNames)
-	} else {
-		err = weavenet.CheckAddressOverlap(addr, ignoreIfaceNames)
-	}
-	if err != nil {
-		fatal(err)
-	}
-	os.Exit(0)
-}
@@ -0,0 +1,3 @@
+FROM weaveworks/weaveexec
+ADD ./plugin /home/weave/
+ENTRYPOINT ["/home/weave/plugin"]
@@ -0,0 +1,156 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"os/signal"
+	"path"
+	"strings"
+	"syscall"
+
+	cni "github.com/appc/cni/pkg/skel"
+	"github.com/docker/libnetwork/ipamapi"
+	weaveapi "github.com/weaveworks/weave/api"
+	"github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common/docker"
+	weavenet "github.com/weaveworks/weave/net"
+	ipamplugin "github.com/weaveworks/weave/plugin/ipam"
+	netplugin "github.com/weaveworks/weave/plugin/net"
+	"github.com/weaveworks/weave/plugin/skel"
+)
+
+var version = "(unreleased version)"
+
+var Log = common.Log
+
+func main() {
+	var (
+		justVersion      bool
+		cniNet           bool
+		cniIpam          bool
+		address          string
+		meshAddress      string
+		logLevel         string
+		noMulticastRoute bool
+	)
+
+	flag.BoolVar(&justVersion, "version", false, "print version and exit")
+	flag.BoolVar(&cniNet, "cni-net", false, "act as a CNI network plugin")
+	flag.BoolVar(&cniIpam, "cni-ipam", false, "act as a CNI IPAM plugin")
+	flag.StringVar(&logLevel, "log-level", "info", "logging level (debug, info, warning, error)")
+	flag.StringVar(&address, "socket", "/run/docker/plugins/weave.sock", "socket on which to listen")
+	flag.StringVar(&meshAddress, "meshsocket", "/run/docker/plugins/weavemesh.sock", "socket on which to listen in mesh mode")
+	flag.BoolVar(&noMulticastRoute, "no-multicast-route", false, "deprecated (this is now the default)")
+
+	flag.Parse()
+
+	if justVersion {
+		fmt.Printf("weave plugin %s\n", version)
+		os.Exit(0)
+	}
+
+	common.SetLogLevel(logLevel)
+
+	weave := weaveapi.NewClient(os.Getenv("WEAVE_HTTP_ADDR"), Log)
+
+	switch {
+	case cniIpam || strings.HasSuffix(os.Args[0], "weave-ipam"):
+		i := ipamplugin.NewIpam(weave)
+		cni.PluginMain(i.CmdAdd, i.CmdDel)
+		os.Exit(0)
+	case cniNet || strings.HasSuffix(os.Args[0], "weave-net"):
+		n := netplugin.NewCNIPlugin(weave)
+		cni.PluginMain(n.CmdAdd, n.CmdDel)
+		os.Exit(0)
+	}
+
+	// API 1.21 is the first version that supports docker network commands
+	dockerClient, err := docker.NewVersionedClientFromEnv("1.21")
+	if err != nil {
+		Log.Fatalf("unable to connect to docker: %s", err)
+	}
+
+	Log.Println("Weave plugin", version, "Command line options:", os.Args[1:])
+	if noMulticastRoute {
+		Log.Warning("--no-multicast-route option has been removed; multicast is off by default")
+	}
+	Log.Info(dockerClient.Info())
+
+	err = run(dockerClient, weave, address, meshAddress)
+	if err != nil {
+		Log.Fatal(err)
+	}
+}
+
+func run(dockerClient *docker.Client, weave *weaveapi.Client, address, meshAddress string) error {
+	endChan := make(chan error, 1)
+	if address != "" {
+		globalListener, err := listenAndServe(dockerClient, weave, address, endChan, "global", false)
+		if err != nil {
+			return err
+		}
+		defer os.Remove(address)
+		defer globalListener.Close()
+	}
+	if meshAddress != "" {
+		meshListener, err := listenAndServe(dockerClient, weave, meshAddress, endChan, "local", true)
+		if err != nil {
+			return err
+		}
+		defer os.Remove(meshAddress)
+		defer meshListener.Close()
+	}
+
+	statusListener, err := weavenet.ListenUnixSocket("/home/weave/status.sock")
+	if err != nil {
+		return err
+	}
+	go serveStatus(statusListener)
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, os.Interrupt, os.Kill, syscall.SIGTERM)
+
+	select {
+	case sig := <-sigChan:
+		Log.Debugf("Caught signal %s; shutting down", sig)
+		return nil
+	case err := <-endChan:
+		return err
+	}
+}
+
+func listenAndServe(dockerClient *docker.Client, weave *weaveapi.Client, address string, endChan chan<- error, scope string, withIpam bool) (net.Listener, error) {
+	name := strings.TrimSuffix(path.Base(address), ".sock")
+	d, err := netplugin.New(dockerClient, weave, name, scope)
+	if err != nil {
+		return nil, err
+	}
+
+	var i ipamapi.Ipam
+	if withIpam {
+		i = ipamplugin.NewIpam(weave)
+	}
+
+	listener, err := weavenet.ListenUnixSocket(address)
+	if err != nil {
+		return nil, err
+	}
+	Log.Printf("Listening on %s for %s scope", address, scope)
+
+	go func() {
+		endChan <- skel.Listen(listener, d, i)
+	}()
+
+	return listener, nil
+}
+
+func serveStatus(listener net.Listener) {
+	server := &http.Server{Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, "ok")
+	})}
+	if err := server.Serve(listener); err != nil {
+		Log.Fatalf("ListenAndServeStatus failed: %s", err)
+	}
+}
@@ -0,0 +1,12 @@
+package main
+
+import (
+	"testing"
+
+	weavetest "github.com/weaveworks/weave/testing"
+)
+
+func TestMain(t *testing.T) {
+	weavetest.TrimTestArgs()
+	main()
+}
@@ -0,0 +1,6 @@
+# This is a nearly-empty image that we use to create a data-only container for persistence
+FROM scratch
+MAINTAINER Weaveworks Inc <help@weave.works>
+ENTRYPOINT ["data-only"]
+# Work round Docker refusing to save an empty image
+COPY Dockerfile /
@@ -4,8 +4,6 @@ MAINTAINER Weaveworks Inc <help@weave.works>
 LABEL works.weave.role=system

 WORKDIR /home/weave
-VOLUME /w
-VOLUME /w-noop
 ENTRYPOINT ["/home/weave/sigproxy", "/home/weave/weave"]

 RUN apk add --update \
@@ -18,8 +16,9 @@ RUN apk add --update \
    bind-tools \
  && rm -rf /var/cache/apk/*

-ADD ./weave ./sigproxy ./weaveproxy /home/weave/
-ADD ./netcheck ./docker_tls_args /usr/bin/
+ADD ./weave ./sigproxy ./weaveproxy ./symlink /home/weave/
+ADD ./weaveutil /usr/bin/
 ADD ./weavewait /w/w
 ADD ./weavewait_noop /w-noop/w
+ADD ./weavewait_nomcast /w-nomcast/w
 ADD ./docker.tgz /
@@ -0,0 +1,18 @@
+#!/bin/sh
+# This lets us force-symlink a bunch of stuff all at once, so we can minimize
+# running containers.
+
+set -e
+
+[ -z "$WEAVE_DEBUG" ] || set -x
+
+target="$1"
+user="$(stat -c '%u:%g' "$target")"
+mode="$(stat -c '%a' "$target")"
+shift 1
+
+for link in "$@" ; do
+  ln -sfT "$target" "$link"
+done
+chown -h "$user" "$@"
+chmod "$mode" "$@"
@@ -6,20 +6,28 @@ import (
 	"strings"

 	"github.com/docker/docker/pkg/mflag"
-	. "github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/common/mflagext"
 	"github.com/weaveworks/weave/proxy"
 )

-var (
-	version = "(unreleased version)"
-)
+var version = "(unreleased version)"
+
+var Log = common.Log
+
+func getenv(key, defaultVal string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return defaultVal
+}

 func main() {
 	var (
 		justVersion bool
 		logLevel    = "info"
-		c           = proxy.Config{ListenAddrs: []string{}}
+		c           proxy.Config
+		withDNS     bool
 	)

 	c.Version = version
@@ -35,11 +43,12 @@ func main() {
 	mflag.BoolVar(&c.NoRewriteHosts, []string{"-no-rewrite-hosts"}, false, "do not automatically rewrite /etc/hosts. Use if you need the docker IP to remain in /etc/hosts")
 	mflag.StringVar(&c.TLSConfig.CACert, []string{"#tlscacert", "-tlscacert"}, "", "Trust certs signed only by this CA")
 	mflag.StringVar(&c.TLSConfig.Cert, []string{"#tlscert", "-tlscert"}, "", "Path to TLS certificate file")
-	mflag.BoolVar(&c.TLSConfig.Enabled, []string{"#tls", "-tls"}, false, "Use TLS; implied by --tls-verify")
+	mflag.BoolVar(&c.TLSConfig.Enabled, []string{"#tls", "-tls"}, false, "Use TLS; implied by --tlsverify")
 	mflag.StringVar(&c.TLSConfig.Key, []string{"#tlskey", "-tlskey"}, "", "Path to TLS key file")
 	mflag.BoolVar(&c.TLSConfig.Verify, []string{"#tlsverify", "-tlsverify"}, false, "Use TLS and verify the remote")
-	mflag.BoolVar(&c.WithDNS, []string{"-with-dns", "w"}, false, "instruct created containers to always use weaveDNS as their nameserver")
+	mflag.BoolVar(&withDNS, []string{"#-with-dns", "#w"}, false, "option removed")
 	mflag.BoolVar(&c.WithoutDNS, []string{"-without-dns"}, false, "instruct created containers to never use weaveDNS as their nameserver")
+	mflag.BoolVar(&c.NoMulticastRoute, []string{"-no-multicast-route"}, false, "do not add a multicast route via the weave interface when attaching containers")
 	mflag.Parse()

 	if justVersion {
@@ -47,23 +56,28 @@ func main() {
 		os.Exit(0)
 	}

-	if c.WithDNS && c.WithoutDNS {
-		Log.Fatalf("Cannot use both '--with-dns' and '--without-dns' flags")
-	}
-
-	SetLogLevel(logLevel)
+	common.SetLogLevel(logLevel)

 	Log.Infoln("weave proxy", version)
 	Log.Infoln("Command line arguments:", strings.Join(os.Args[1:], " "))

+	if withDNS {
+		Log.Warning("--with-dns option has been removed; DNS is on by default")
+	}
+
+	c.Image = getenv("EXEC_IMAGE", "weaveworks/weaveexec")
+	c.DockerBridge = getenv("DOCKER_BRIDGE", "docker0")
+	c.DockerHost = getenv("DOCKER_HOST", "unix:///var/run/docker.sock")
+
 	p, err := proxy.NewProxy(c)
 	if err != nil {
 		Log.Fatalf("Could not start proxy: %s", err)
 	}
+	defer p.Stop()

 	listeners := p.Listen()
 	p.AttachExistingContainers()
 	go p.Serve(listeners)
 	go p.ListenAndServeStatus("/home/weave/status.sock")
-	SignalHandlerLoop()
+	common.SignalHandlerLoop()
 }
@@ -3,4 +3,6 @@ MAINTAINER Weaveworks Inc <help@weave.works>
 LABEL works.weave.role=system
 WORKDIR /home/weave
 ADD ./weaver /home/weave/
+ADD weavedata.db /weavedb/
+COPY ca-certificates.crt /etc/ssl/certs/
 ENTRYPOINT ["/home/weave/weaver"]
@@ -0,0 +1,63 @@
+package main
+
+import (
+	"sync/atomic"
+	"syscall"
+	"time"
+
+	"github.com/weaveworks/go-checkpoint"
+)
+
+var checker *checkpoint.Checker
+var newVersion atomic.Value
+
+const (
+	updateCheckPeriod = 6 * time.Hour
+)
+
+func checkForUpdates(dockerVersion string, network string) {
+	newVersion.Store("")
+
+	handleResponse := func(r *checkpoint.CheckResponse, err error) {
+		if err != nil {
+			Log.Printf("Error checking version: %v", err)
+			return
+		}
+		if r.Outdated {
+			newVersion.Store(r.CurrentVersion)
+			Log.Printf("Weave version %s is available; please update at %s",
+				r.CurrentVersion, r.CurrentDownloadURL)
+		}
+	}
+
+	var uts syscall.Utsname
+	syscall.Uname(&uts)
+	flags := map[string]string{
+		"docker-version": dockerVersion,
+		"kernel-version": charsToString(uts.Release[:]),
+	}
+	if network != "" {
+		flags["network"] = network
+	}
+
+	// Start background version checking
+	params := checkpoint.CheckParams{
+		Product:       "weave-net",
+		Version:       version,
+		SignatureFile: "",
+		Flags:         flags,
+	}
+	checker = checkpoint.CheckInterval(&params, updateCheckPeriod, handleResponse)
+}
+
+func charsToString(ca []int8) string {
+	s := make([]byte, len(ca))
+	i := 0
+	for ; i < len(ca); i++ {
+		if ca[i] == 0 {
+			break
+		}
+		s[i] = uint8(ca[i])
+	}
+	return string(s[:i])
+}
@@ -1,17 +1,22 @@
 package main

 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
+	"net/http"
+	"strings"
+	"text/template"
+	"time"
+
 	"github.com/gorilla/mux"
-	. "github.com/weaveworks/weave/common"
+	"github.com/weaveworks/mesh"
+
+	"github.com/weaveworks/go-checkpoint"
 	"github.com/weaveworks/weave/ipam"
 	"github.com/weaveworks/weave/nameserver"
 	"github.com/weaveworks/weave/net/address"
 	weave "github.com/weaveworks/weave/router"
-	"net/http"
-	"strings"
-	"text/template"
 )

 var rootTemplate = template.New("root").Funcs(map[string]interface{}{
@@ -24,14 +29,74 @@ var rootTemplate = template.New("root").Funcs(map[string]interface{}{
 		}
 		return count
 	},
-	"printConnectionCounts": func(conns []weave.LocalConnectionStatus) string {
+	"printList": func(list []string) string {
+		if len(list) == 0 {
+			return "none"
+		}
+		return strings.Join(list, ", ")
+	},
+	"printIPAMRanges": func(router weave.NetworkRouterStatus, status ipam.Status) string {
+		var buffer bytes.Buffer
+
+		type stats struct {
+			ips       uint32
+			nickname  string
+			reachable bool
+		}
+
+		peerStats := make(map[string]*stats)
+
+		for _, entry := range status.Entries {
+			s, found := peerStats[entry.Peer]
+			if !found {
+				s = &stats{nickname: entry.Nickname, reachable: entry.IsKnownPeer}
+				peerStats[entry.Peer] = s
+			}
+			s.ips += entry.Size
+		}
+
+		printOwned := func(name string, nickName string, reachable bool, ips uint32) {
+			reachableStr := ""
+			if !reachable {
+				reachableStr = "- unreachable!"
+			}
+			percentageRanges := float32(ips) * 100.0 / float32(status.RangeNumIPs)
+
+			displayName := name + "(" + nickName + ")"
+			fmt.Fprintf(&buffer, "%-37v %8d IPs (%04.1f%% of total) %s\n",
+				displayName, ips, percentageRanges, reachableStr)
+		}
+
+		// print the local info first
+		if ourStats := peerStats[router.Name]; ourStats != nil {
+			printOwned(router.Name, ourStats.nickname, true, ourStats.ips)
+		}
+
+		// and then the rest
+		for peer, stats := range peerStats {
+			if peer != router.Name {
+				printOwned(peer, stats.nickname, stats.reachable, stats.ips)
+			}
+		}
+
+		return buffer.String()
+	},
+	"allIPAMOwnersUnreachable": func(status ipam.Status) bool {
+		for _, entry := range status.Entries {
+			if entry.Size > 0 && entry.IsKnownPeer {
+				return false
+			}
+		}
+		return true
+	},
+	"printConnectionCounts": func(conns []mesh.LocalConnectionStatus) string {
 		counts := make(map[string]int)
 		for _, conn := range conns {
 			counts[conn.State]++
 		}
 		return printCounts(counts, []string{"established", "pending", "retrying", "failed", "connecting"})
 	},
-	"printPeerConnectionCounts": func(peers []weave.PeerStatus) string {
+	"printPeerConnectionCounts": func(peers []mesh.PeerStatus) string {
 		counts := make(map[string]int)
 		for _, peer := range peers {
 			for _, conn := range peer.Connections {
@@ -75,40 +140,52 @@ func defTemplate(name string, text string) *template.Template {
 }

 var statusTemplate = defTemplate("status", `\
-       Version: {{.Version}}
+        Version: {{.Version}} ({{.VersionCheck}})

-       Service: router
-      Protocol: {{.Router.Protocol}} \
+        Service: router
+       Protocol: {{.Router.Protocol}} \
 {{if eq .Router.ProtocolMinVersion .Router.ProtocolMaxVersion}}\
 {{.Router.ProtocolMaxVersion}}\
 {{else}}\
 {{.Router.ProtocolMinVersion}}..{{.Router.ProtocolMaxVersion}}\
 {{end}}
-          Name: {{.Router.Name}}({{.Router.NickName}})
-    Encryption: {{printState .Router.Encryption}}
- PeerDiscovery: {{printState .Router.PeerDiscovery}}
-       Targets: {{len .Router.Targets}}
-   Connections: {{len .Router.Connections}}{{with printConnectionCounts .Router.Connections}} ({{.}}){{end}}
-         Peers: {{len .Router.Peers}}{{with printPeerConnectionCounts .Router.Peers}} (with {{.}} connections){{end}}
+           Name: {{.Router.Name}}({{.Router.NickName}})
+     Encryption: {{printState .Router.Encryption}}
+  PeerDiscovery: {{printState .Router.PeerDiscovery}}
+        Targets: {{len .Router.Targets}}
+    Connections: {{len .Router.Connections}}{{with printConnectionCounts .Router.Connections}} ({{.}}){{end}}
+          Peers: {{len .Router.Peers}}{{with printPeerConnectionCounts .Router.Peers}} (with {{.}} connections){{end}}
+ TrustedSubnets: {{printList .Router.TrustedSubnets}}
 {{if .IPAM}}\

-       Service: ipam
+        Service: ipam
 {{if .IPAM.Entries}}\
-     Consensus: achieved
-{{else if .IPAM.Paxos}}\
-     Consensus: waiting (quorum: {{.IPAM.Paxos.Quorum}}, known: {{.IPAM.Paxos.KnownNodes}})
+{{if allIPAMOwnersUnreachable .IPAM}}\
+         Status: all IP ranges owned by unreachable peers - use 'rmpeer' if they are dead
+{{else if len .IPAM.PendingAllocates}}\
+         Status: waiting for IP range grant from peers
 {{else}}\
-     Consensus: deferred
+         Status: ready
 {{end}}\
-         Range: {{.IPAM.Range}}
- DefaultSubnet: {{.IPAM.DefaultSubnet}}
+{{else if .IPAM.Paxos}}\
+{{if .IPAM.Paxos.Elector}}\
+         Status: awaiting consensus (quorum: {{.IPAM.Paxos.Quorum}}, known: {{.IPAM.Paxos.KnownNodes}})
+{{else}}\
+         Status: priming
+{{end}}\
+{{else}}\
+         Status: idle
+{{end}}\
+          Range: {{.IPAM.Range}}
+  DefaultSubnet: {{.IPAM.DefaultSubnet}}
 {{end}}\
 {{if .DNS}}\

-       Service: dns
-        Domain: {{.DNS.Domain}}
-           TTL: {{.DNS.TTL}}
-       Entries: {{countDNSEntries .DNS.Entries}}
+        Service: dns
+         Domain: {{.DNS.Domain}}
+       Upstream: {{printList .DNS.Upstream}}
+            TTL: {{.DNS.TTL}}
+        Entries: {{countDNSEntries .DNS.Entries}}
 {{end}}\
 `)

@@ -128,7 +205,7 @@ var peersTemplate = defTemplate("peers", `\
 {{.Name}}({{.NickName}})
 {{range .Connections}}\
   {{if .Outbound}}->{{else}}<-{{end}} {{printf "%-21v" .Address}} \
-{{$nameNickName := printf "%v(%v)" .Name .NickName}}{{printf "%-32v" $nameNickName}} \
+{{$nameNickName := printf "%v(%v)" .Name .NickName}}{{printf "%-37v" $nameNickName}} \
 {{if .Established}}established{{else}}pending{{end}}
 {{end}}\
 {{end}}\
@@ -144,18 +221,54 @@ var dnsEntriesTemplate = defTemplate("dnsEntries", `\
 {{end}}\
 `)

-type WeaveStatus struct {
-	Version string
-	Router  *weave.Status      `json:"Router,omitempty"`
-	IPAM    *ipam.Status       `json:"IPAM,omitempty"`
-	DNS     *nameserver.Status `json:"DNS,omitempty"`
+var ipamTemplate = defTemplate("ipamTemplate", `{{printIPAMRanges .Router .IPAM}}`)
+
+type VersionCheck struct {
+	Enabled     bool
+	NewVersion  string
+	NextCheckAt time.Time
 }

-func HandleHTTP(muxRouter *mux.Router, version string, router *weave.Router, allocator *ipam.Allocator, defaultSubnet address.CIDR, ns *nameserver.Nameserver, dnsserver *nameserver.DNSServer) {
+func versionCheck() *VersionCheck {
+	v := &VersionCheck{}
+	if checkpoint.IsCheckDisabled() {
+		return v
+	}
+
+	v.Enabled = true
+	v.NewVersion = newVersion.Load().(string)
+	v.NextCheckAt = checker.NextCheckAt()
+
+	return v
+}
+
+func (v *VersionCheck) String() string {
+	switch {
+	case !v.Enabled:
+		return "version check update disabled"
+	case v.NewVersion != "":
+		return fmt.Sprintf("version %s available - please upgrade!",
+			v.NewVersion)
+	default:
+		return fmt.Sprintf("up to date; next check at %s",
+			v.NextCheckAt.Format("2006/01/02 15:04:05"))
+	}
+}
+
+type WeaveStatus struct {
+	Version      string
+	VersionCheck *VersionCheck              `json:"VersionCheck,omitempty"`
+	Router       *weave.NetworkRouterStatus `json:"Router,omitempty"`
+	IPAM         *ipam.Status               `json:"IPAM,omitempty"`
+	DNS          *nameserver.Status         `json:"DNS,omitempty"`
+}
+
+func HandleHTTP(muxRouter *mux.Router, version string, router *weave.NetworkRouter, allocator *ipam.Allocator, defaultSubnet address.CIDR, ns *nameserver.Nameserver, dnsserver *nameserver.DNSServer) {
 	status := func() WeaveStatus {
 		return WeaveStatus{
 			version,
-			weave.NewStatus(router),
+			versionCheck(),
+			weave.NewNetworkRouterStatus(router),
 			ipam.NewStatus(allocator, defaultSubnet),
 			nameserver.NewStatus(ns, dnsserver)}
 	}
@@ -173,7 +286,13 @@ func HandleHTTP(muxRouter *mux.Router, version string, router *weave.Router, all

 	muxRouter.Methods("GET").Path("/report").Queries("format", "{format}").HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
-			formatTemplate, err := template.New("format").Parse(mux.Vars(r)["format"])
+			funcs := template.FuncMap{
+				"json": func(v interface{}) string {
+					a, _ := json.Marshal(v)
+					return string(a)
+				},
+			}
+			formatTemplate, err := template.New("format").Funcs(funcs).Parse(mux.Vars(r)["format"])
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusBadRequest)
 				return
@@ -199,5 +318,5 @@ func HandleHTTP(muxRouter *mux.Router, version string, router *weave.Router, all
 	defHandler("/status/connections", connectionsTemplate)
 	defHandler("/status/peers", peersTemplate)
 	defHandler("/status/dns", dnsEntriesTemplate)
-
+	defHandler("/status/ipam", ipamTemplate)
 }
@@ -7,16 +7,20 @@ import (
 	_ "net/http/pprof"
 	"os"
 	"runtime"
+	"strconv"
 	"strings"
 	"time"

-	"github.com/davecheney/profile"
 	"github.com/docker/docker/pkg/mflag"
 	"github.com/gorilla/mux"
+	"github.com/pkg/profile"
+	"github.com/weaveworks/mesh"

-	. "github.com/weaveworks/weave/common"
+	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/common/docker"
+	"github.com/weaveworks/weave/db"
 	"github.com/weaveworks/weave/ipam"
+	"github.com/weaveworks/weave/ipam/tracker"
 	"github.com/weaveworks/weave/nameserver"
 	weavenet "github.com/weaveworks/weave/net"
 	"github.com/weaveworks/weave/net/address"
@@ -25,6 +29,84 @@ import (

 var version = "(unreleased version)"

+var Log = common.Log
+
+type ipamConfig struct {
+	IPRangeCIDR   string
+	IPSubnetCIDR  string
+	PeerCount     int
+	Mode          string
+	Observer      bool
+	SeedPeerNames []mesh.PeerName
+}
+
+type dnsConfig struct {
+	Domain                 string
+	ListenAddress          string
+	TTL                    int
+	ClientTimeout          time.Duration
+	EffectiveListenAddress string
+	ResolvConf             string
+}
+
+func (c *ipamConfig) Enabled() bool {
+	var (
+		hasPeerCount = c.PeerCount > 0
+		hasMode      = len(c.Mode) > 0
+		hasRange     = c.IPRangeCIDR != ""
+		hasSubnet    = c.IPSubnetCIDR != ""
+	)
+	switch {
+	case !(hasPeerCount || hasMode || hasRange || hasSubnet):
+		return false
+	case !hasRange && hasSubnet:
+		Log.Fatal("--ipalloc-default-subnet specified without --ipalloc-range.")
+	case !hasRange:
+		Log.Fatal("--ipalloc-init or --init-peer-count specified without --ipalloc-range.")
+	case hasMode && hasPeerCount:
+		Log.Fatal("At most one of --ipalloc-init or --init-peer-count may be specified.")
+	}
+	if hasMode {
+		if err := c.parseMode(); err != nil {
+			Log.Fatalf("Unable to parse --ipalloc-init: %s", err)
+		}
+	}
+	return true
+}
+
+func (c *ipamConfig) parseMode() error {
+	modeAndParam := strings.SplitN(c.Mode, "=", 2)
+
+	switch modeAndParam[0] {
+	case "consensus":
+		if len(modeAndParam) == 2 {
+			peerCount, err := strconv.Atoi(modeAndParam[1])
+			if err != nil {
+				return fmt.Errorf("bad consensus parameter: %s", err)
+			}
+			c.PeerCount = peerCount
+		}
+	case "seed":
+		if len(modeAndParam) != 2 {
+			return fmt.Errorf("seed mode requires peer name list")
+		}
+		seedPeerNames, err := parsePeerNames(modeAndParam[1])
+		if err != nil {
+			return fmt.Errorf("bad seed parameter: %s", err)
+		}
+		c.SeedPeerNames = seedPeerNames
+	case "observer":
+		if len(modeAndParam) != 1 {
+			return fmt.Errorf("observer mode takes no parameter")
+		}
+		c.Observer = true
+	default:
+		return fmt.Errorf("unknown mode: %s", modeAndParam[0])
+	}
+
+	return nil
+}
+
 func main() {
 	procs := runtime.NumCPU()
 	// packet sniffing can block an OS thread, so we need one thread
@@ -35,46 +117,43 @@ func main() {
 	runtime.GOMAXPROCS(procs)

 	var (
-		// flags that cause immediate exit
-		justVersion          bool
-		createDatapath       bool
-		deleteDatapath       bool
-		addDatapathInterface string
+		justVersion        bool
+		config             mesh.Config
+		networkConfig      weave.NetworkConfig
+		protocolMinVersion int
+		resume             bool
+		ifaceName          string
+		routerName         string
+		nickName           string
+		password           string
+		pktdebug           bool
+		logLevel           string
+		prof               string
+		bufSzMB            int
+		noDiscovery        bool
+		httpAddr           string
+		ipamConfig         ipamConfig
+		dockerAPI          string
+		peers              []string
+		noDNS              bool
+		dnsConfig          dnsConfig
+		datapathName       string
+		trustedSubnetStr   string
+		dbPrefix           string
+		isAWSVPC           bool

-		config                    weave.Config
-		protocolMinVersion        int
-		ifaceName                 string
-		routerName                string
-		nickName                  string
-		password                  string
-		pktdebug                  bool
-		logLevel                  string
-		prof                      string
-		bufSzMB                   int
-		noDiscovery               bool
-		httpAddr                  string
-		iprangeCIDR               string
-		ipsubnetCIDR              string
-		peerCount                 int
-		dockerAPI                 string
-		peers                     []string
-		noDNS                     bool
-		dnsDomain                 string
-		dnsListenAddress          string
-		dnsTTL                    int
-		dnsClientTimeout          time.Duration
-		dnsEffectiveListenAddress string
-		iface                     *net.Interface
-		datapathName              string
+		defaultDockerHost = "unix:///var/run/docker.sock"
 	)

-	mflag.BoolVar(&justVersion, []string{"#version", "-version"}, false, "print version and exit")
-	mflag.BoolVar(&createDatapath, []string{"-create-datapath"}, false, "create ODP datapath and exit")
-	mflag.BoolVar(&deleteDatapath, []string{"-delete-datapath"}, false, "delete ODP datapath and exit")
-	mflag.StringVar(&addDatapathInterface, []string{"-add-datapath-iface"}, "", "add a network interface to the ODP datapath and exit")
+	if val := os.Getenv("DOCKER_HOST"); val != "" {
+		defaultDockerHost = val
+	}

-	mflag.IntVar(&config.Port, []string{"#port", "-port"}, weave.Port, "router port")
-	mflag.IntVar(&protocolMinVersion, []string{"-min-protocol-version"}, weave.ProtocolMinVersion, "minimum weave protocol version")
+	mflag.BoolVar(&justVersion, []string{"#version", "-version"}, false, "print version and exit")
+	mflag.StringVar(&config.Host, []string{"-host"}, "", "router host")
+	mflag.IntVar(&config.Port, []string{"#port", "-port"}, mesh.Port, "router port")
+	mflag.IntVar(&protocolMinVersion, []string{"-min-protocol-version"}, mesh.ProtocolMinVersion, "minimum weave protocol version")
+	mflag.BoolVar(&resume, []string{"-resume"}, false, "resume connections to previous peers")
 	mflag.StringVar(&ifaceName, []string{"#iface", "-iface"}, "", "name of interface to capture/inject from (disabled if blank)")
 	mflag.StringVar(&routerName, []string{"#name", "-name"}, "", "name of router (defaults to MAC of interface)")
 	mflag.StringVar(&nickName, []string{"#nickname", "-nickname"}, "", "nickname of peer (defaults to hostname)")
@@ -85,18 +164,23 @@ func main() {
 	mflag.IntVar(&config.ConnLimit, []string{"#connlimit", "#-connlimit", "-conn-limit"}, 30, "connection limit (0 for unlimited)")
 	mflag.BoolVar(&noDiscovery, []string{"#nodiscovery", "#-nodiscovery", "-no-discovery"}, false, "disable peer discovery")
 	mflag.IntVar(&bufSzMB, []string{"#bufsz", "-bufsz"}, 8, "capture buffer size in MB")
-	mflag.StringVar(&httpAddr, []string{"#httpaddr", "#-httpaddr", "-http-addr"}, fmt.Sprintf(":%d", weave.HTTPPort), "address to bind HTTP interface to (disabled if blank, absolute path indicates unix domain socket)")
-	mflag.StringVar(&iprangeCIDR, []string{"#iprange", "#-iprange", "-ipalloc-range"}, "", "IP address range reserved for automatic allocation, in CIDR notation")
-	mflag.StringVar(&ipsubnetCIDR, []string{"#ipsubnet", "#-ipsubnet", "-ipalloc-default-subnet"}, "", "subnet to allocate within by default, in CIDR notation")
-	mflag.IntVar(&peerCount, []string{"#initpeercount", "#-initpeercount", "-init-peer-count"}, 0, "number of peers in network (for IP address allocation)")
-	mflag.StringVar(&dockerAPI, []string{"#api", "#-api", "-docker-api"}, "", "Docker API endpoint, e.g. unix:///var/run/docker.sock")
+	mflag.StringVar(&httpAddr, []string{"#httpaddr", "#-httpaddr", "-http-addr"}, "", "address to bind HTTP interface to (disabled if blank, absolute path indicates unix domain socket)")
+	mflag.StringVar(&ipamConfig.Mode, []string{"-ipalloc-init"}, "", "allocator initialisation strategy (consensus, seed or observer)")
+	mflag.StringVar(&ipamConfig.IPRangeCIDR, []string{"#iprange", "#-iprange", "-ipalloc-range"}, "", "IP address range reserved for automatic allocation, in CIDR notation")
+	mflag.StringVar(&ipamConfig.IPSubnetCIDR, []string{"#ipsubnet", "#-ipsubnet", "-ipalloc-default-subnet"}, "", "subnet to allocate within by default, in CIDR notation")
+	mflag.IntVar(&ipamConfig.PeerCount, []string{"#initpeercount", "#-initpeercount", "-init-peer-count"}, 0, "number of peers in network (for IP address allocation)")
+	mflag.StringVar(&dockerAPI, []string{"#api", "#-api", "-docker-api"}, defaultDockerHost, "Docker API endpoint")
 	mflag.BoolVar(&noDNS, []string{"-no-dns"}, false, "disable DNS server")
-	mflag.StringVar(&dnsDomain, []string{"-dns-domain"}, nameserver.DefaultDomain, "local domain to server requests for")
-	mflag.StringVar(&dnsListenAddress, []string{"-dns-listen-address"}, nameserver.DefaultListenAddress, "address to listen on for DNS requests")
-	mflag.IntVar(&dnsTTL, []string{"-dns-ttl"}, nameserver.DefaultTTL, "TTL for DNS request from our domain")
-	mflag.DurationVar(&dnsClientTimeout, []string{"-dns-fallback-timeout"}, nameserver.DefaultClientTimeout, "timeout for fallback DNS requests")
-	mflag.StringVar(&dnsEffectiveListenAddress, []string{"-dns-effective-listen-address"}, "", "address DNS will actually be listening, after Docker port mapping")
+	mflag.StringVar(&dnsConfig.Domain, []string{"-dns-domain"}, nameserver.DefaultDomain, "local domain to server requests for")
+	mflag.StringVar(&dnsConfig.ListenAddress, []string{"-dns-listen-address"}, nameserver.DefaultListenAddress, "address to listen on for DNS requests")
+	mflag.IntVar(&dnsConfig.TTL, []string{"-dns-ttl"}, nameserver.DefaultTTL, "TTL for DNS request from our domain")
+	mflag.DurationVar(&dnsConfig.ClientTimeout, []string{"-dns-fallback-timeout"}, nameserver.DefaultClientTimeout, "timeout for fallback DNS requests")
+	mflag.StringVar(&dnsConfig.EffectiveListenAddress, []string{"-dns-effective-listen-address"}, "", "address DNS will actually be listening, after Docker port mapping")
+	mflag.StringVar(&dnsConfig.ResolvConf, []string{"-resolv-conf"}, "", "path to resolver configuration for fallback DNS lookups")
 	mflag.StringVar(&datapathName, []string{"-datapath"}, "", "ODP datapath name")
+	mflag.StringVar(&trustedSubnetStr, []string{"-trusted-subnets"}, "", "comma-separated list of trusted subnets in CIDR notation")
+	mflag.StringVar(&dbPrefix, []string{"-db-prefix"}, "/weavedb/weave", "pathname/prefix of filename to store data")
+	mflag.BoolVar(&isAWSVPC, []string{"-awsvpc"}, false, "use AWS VPC for routing")

 	// crude way of detecting that we probably have been started in a
 	// container, with `weave launch` --> suppress misleading paths in
@@ -109,157 +193,116 @@ func main() {
 	mflag.Parse()

 	peers = mflag.Args()
+	if resume && len(peers) > 0 {
+		Log.Fatalf("You must not specify an initial peer list in conjunction with --resume")
+	}

-	SetLogLevel(logLevel)
+	common.SetLogLevel(logLevel)

-	switch {
-	case justVersion:
+	if justVersion {
 		fmt.Printf("weave router %s\n", version)
 		os.Exit(0)
-
-	case createDatapath:
-		err, odp_supported := weave.CreateDatapath(datapathName)
-		if !odp_supported {
-			if err != nil {
-				Log.Error(err)
-			}
-
-			// When the kernel lacks ODP support, exit
-			// with a special status to distinguish it for
-			// the weave script.
-			os.Exit(17)
-		}
-
-		checkFatal(err)
-		os.Exit(0)
-
-	case deleteDatapath:
-		checkFatal(weave.DeleteDatapath(datapathName))
-		os.Exit(0)
-
-	case addDatapathInterface != "":
-		checkFatal(weave.AddDatapathInterface(datapathName, addDatapathInterface))
-		os.Exit(0)
 	}

 	Log.Println("Command line options:", options())
-	Log.Println("Command line peers:", peers)

-	if protocolMinVersion < weave.ProtocolMinVersion || protocolMinVersion > weave.ProtocolMaxVersion {
-		Log.Fatalf("--min-protocol-version must be in range [%d,%d]", weave.ProtocolMinVersion, weave.ProtocolMaxVersion)
+	if prof != "" {
+		defer profile.Start(profile.CPUProfile, profile.ProfilePath(prof), profile.NoShutdownHook).Stop()
+	}
+
+	if protocolMinVersion < mesh.ProtocolMinVersion || protocolMinVersion > mesh.ProtocolMaxVersion {
+		Log.Fatalf("--min-protocol-version must be in range [%d,%d]", mesh.ProtocolMinVersion, mesh.ProtocolMaxVersion)
 	}
 	config.ProtocolMinVersion = byte(protocolMinVersion)

-	var fastDPOverlay weave.Overlay
-	if datapathName != "" {
-		// A datapath name implies that "Bridge" and "Overlay"
-		// packet handling use fast datapath, although other
-		// options can override that below.  Even if both
-		// things are overridden, we might need bridging on
-		// the datapath.
-		fastdp, err := weave.NewFastDatapath(weave.FastDatapathConfig{
-			DatapathName: datapathName,
-			Port:         config.Port,
-		})
-
-		checkFatal(err)
-		config.Bridge = fastdp.Bridge()
-		fastDPOverlay = fastdp.Overlay()
-	}
-
-	if ifaceName != "" {
-		// -iface can coexist with -datapath, because
-		// pcap-based packet capture is a bit more efficient
-		// than capture via ODP misses, even when using an
-		// ODP-based bridge.  So when using weave encyption,
-		// it's preferable to use -iface.
-		var err error
-		iface, err = weavenet.EnsureInterface(ifaceName)
-		checkFatal(err)
-
-		// bufsz flag is in MB
-		config.Bridge, err = weave.NewPcap(iface, bufSzMB*1024*1024)
-		checkFatal(err)
-	}
-
-	if password == "" {
-		password = os.Getenv("WEAVE_PASSWORD")
-	}
-
-	if password == "" {
-		Log.Println("Communication between peers is unencrypted.")
+	if pktdebug {
+		networkConfig.PacketLogging = packetLogging{}
 	} else {
-		config.Password = []byte(password)
-		Log.Println("Communication between peers is encrypted.")
-
-		// fastdp doesn't support encryption
-		fastDPOverlay = nil
+		networkConfig.PacketLogging = nopPacketLogging{}
 	}

-	overlays := weave.NewOverlaySwitch()
-	if fastDPOverlay != nil {
-		overlays.Add("fastdp", fastDPOverlay)
-	}
-	sleeve := weave.NewSleeveOverlay(config.Port)
-	overlays.Add("sleeve", sleeve)
-	overlays.SetCompatOverlay(sleeve)
-	config.Overlay = overlays
+	overlay, bridge := createOverlay(datapathName, ifaceName, isAWSVPC, config.Host, config.Port, bufSzMB)
+	networkConfig.Bridge = bridge

-	if routerName == "" {
-		if iface == nil {
-			Log.Fatal("Either an interface must be specified with --iface or a name with -name")
-		}
-		routerName = iface.HardwareAddr.String()
-	}
-
-	name, err := weave.PeerNameFromUserInput(routerName)
-	checkFatal(err)
+	name := peerName(routerName, bridge.Interface())

 	if nickName == "" {
+		var err error
 		nickName, err = os.Hostname()
 		checkFatal(err)
 	}

-	if prof != "" {
-		p := *profile.CPUProfile
-		p.ProfilePath = prof
-		p.NoShutdownHook = true
-		defer profile.Start(&p).Stop()
-	}
-
+	config.Password = determinePassword(password)
+	config.TrustedSubnets = parseTrustedSubnets(trustedSubnetStr)
 	config.PeerDiscovery = !noDiscovery

-	if pktdebug {
-		config.PacketLogging = packetLogging{}
-	} else {
-		config.PacketLogging = nopPacketLogging{}
+	if isAWSVPC && len(config.Password) > 0 {
+		Log.Fatalf("--awsvpc mode is not compatible with the --password option")
 	}

-	router := weave.NewRouter(config, name, nickName)
+	db, err := db.NewBoltDB(dbPrefix + "data.db")
+	checkFatal(err)
+	defer db.Close()
+
+	router := weave.NewNetworkRouter(config, networkConfig, name, nickName, overlay, db)
 	Log.Println("Our name is", router.Ourself)

+	if peers, err = router.InitialPeers(resume, peers); err != nil {
+		Log.Fatal("Unable to get initial peer set: ", err)
+	}
+
 	var dockerCli *docker.Client
+	dockerVersion := "none"
 	if dockerAPI != "" {
 		dc, err := docker.NewClient(dockerAPI)
 		if err != nil {
 			Log.Fatal("Unable to start docker client: ", err)
+		} else {
+			Log.Info(dc.Info())
 		}
 		dockerCli = dc
+		dockerVersion = dockerCli.DockerVersion()
 	}
+
+	network := ""
+	if isAWSVPC {
+		network = "awsvpc"
+	}
+	checkForUpdates(dockerVersion, network)
+
 	observeContainers := func(o docker.ContainerObserver) {
 		if dockerCli != nil {
-			if err = dockerCli.AddObserver(o); err != nil {
+			if err := dockerCli.AddObserver(o); err != nil {
 				Log.Fatal("Unable to start watcher", err)
 			}
 		}
 	}
-	var allocator *ipam.Allocator
-	var defaultSubnet address.CIDR
-	if iprangeCIDR != "" {
-		allocator, defaultSubnet = createAllocator(router, iprangeCIDR, ipsubnetCIDR, determineQuorum(peerCount, peers))
+	isKnownPeer := func(name mesh.PeerName) bool {
+		return router.Peers.Fetch(name) != nil
+	}
+
+	var (
+		allocator     *ipam.Allocator
+		defaultSubnet address.CIDR
+		trackerName   string
+	)
+	if ipamConfig.Enabled() {
+		var t tracker.LocalRangeTracker
+		if isAWSVPC {
+			Log.Infoln("Creating AWSVPC LocalRangeTracker")
+			t, err = tracker.NewAWSVPCTracker()
+			if err != nil {
+				Log.Fatalf("Cannot create AWSVPC LocalRangeTracker: %s", err)
+			}
+			trackerName = "awsvpc"
+		}
+		allocator, defaultSubnet = createAllocator(router, ipamConfig, db, t, isKnownPeer)
 		observeContainers(allocator)
-	} else if peerCount > 0 {
-		Log.Fatal("--init-peer-count flag specified without --ipalloc-range")
+		if dockerCli != nil {
+			ids, err := dockerCli.AllContainerIDs()
+			checkFatal(err)
+			allocator.PruneOwned(ids)
+		}
 	}

 	var (
@@ -267,28 +310,17 @@ func main() {
 		dnsserver *nameserver.DNSServer
 	)
 	if !noDNS {
-		ns = nameserver.New(router.Ourself.Peer.Name, router.Peers, dnsDomain)
-		ns.SetGossip(router.NewGossip("nameserver", ns))
+		ns, dnsserver = createDNSServer(dnsConfig, router.Router, isKnownPeer)
 		observeContainers(ns)
 		ns.Start()
 		defer ns.Stop()
-		dnsserver, err = nameserver.NewDNSServer(ns, dnsDomain, dnsListenAddress,
-			dnsEffectiveListenAddress, uint32(dnsTTL), dnsClientTimeout)
-		if err != nil {
-			Log.Fatal("Unable to start dns server: ", err)
-		}
-		listenAddr := dnsListenAddress
-		if dnsEffectiveListenAddress != "" {
-			listenAddr = dnsEffectiveListenAddress
-		}
-		Log.Println("Listening for DNS queries on", listenAddr)
 		dnsserver.ActivateAndServe()
 		defer dnsserver.Stop()
 	}

 	router.Start()
-	if errors := router.ConnectionMaker.InitiateConnections(peers, false); len(errors) > 0 {
-		Log.Fatal(ErrorMessages(errors))
+	if errors := router.InitiateConnections(peers, false); len(errors) > 0 {
+		Log.Fatal(common.ErrorMessages(errors))
 	}

 	// The weave script always waits for a status call to succeed,
@@ -297,19 +329,19 @@ func main() {
 	if httpAddr != "" {
 		muxRouter := mux.NewRouter()
 		if allocator != nil {
-			allocator.HandleHTTP(muxRouter, defaultSubnet, dockerCli)
+			allocator.HandleHTTP(muxRouter, defaultSubnet, trackerName, dockerCli)
 		}
 		if ns != nil {
 			ns.HandleHTTP(muxRouter, dockerCli)
 		}
 		router.HandleHTTP(muxRouter)
 		HandleHTTP(muxRouter, version, router, allocator, defaultSubnet, ns, dnsserver)
-		http.Handle("/", muxRouter)
+		http.Handle("/", common.LoggingHTTPHandler(muxRouter))
 		Log.Println("Listening for HTTP control messages on", httpAddr)
-		go listenAndServeHTTP(httpAddr, muxRouter)
+		go listenAndServeHTTP(httpAddr)
 	}

-	SignalHandlerLoop(router)
+	common.SignalHandlerLoop(router)
 }

 func options() map[string]string {
@@ -352,41 +384,105 @@ func (nopPacketLogging) LogPacket(string, weave.PacketKey) {
 func (nopPacketLogging) LogForwardPacket(string, weave.ForwardPacketKey) {
 }

-func parseAndCheckCIDR(cidrStr string) address.CIDR {
-	_, cidr, err := address.ParseCIDR(cidrStr)
-	checkFatal(err)
+func createOverlay(datapathName string, ifaceName string, isAWSVPC bool, host string, port int, bufSzMB int) (weave.NetworkOverlay, weave.Bridge) {
+	overlay := weave.NewOverlaySwitch()
+	var bridge weave.Bridge
+	var ignoreSleeve bool

-	if cidr.Size() < ipam.MinSubnetSize {
-		Log.Fatalf("Allocation range smaller than minimum size %d: %s", ipam.MinSubnetSize, cidrStr)
+	switch {
+	case isAWSVPC:
+		vpc := weave.NewAWSVPC()
+		overlay.Add("awsvpc", vpc)
+		bridge = weave.NullBridge{}
+		// Currently, we do not support any overlay with AWSVPC
+		ignoreSleeve = true
+	case datapathName != "" && ifaceName != "":
+		Log.Fatal("At most one of --datapath and --iface must be specified.")
+	case datapathName != "":
+		iface, err := weavenet.EnsureInterface(datapathName)
+		checkFatal(err)
+		fastdp, err := weave.NewFastDatapath(iface, port)
+		checkFatal(err)
+		bridge = fastdp.Bridge()
+		overlay.Add("fastdp", fastdp.Overlay())
+	case ifaceName != "":
+		iface, err := weavenet.EnsureInterface(ifaceName)
+		checkFatal(err)
+		bridge, err = weave.NewPcap(iface, bufSzMB*1024*1024) // bufsz flag is in MB
+		checkFatal(err)
+	default:
+		bridge = weave.NullBridge{}
 	}
-	return cidr
+
+	if !ignoreSleeve {
+		sleeve := weave.NewSleeveOverlay(host, port)
+		overlay.Add("sleeve", sleeve)
+		overlay.SetCompatOverlay(sleeve)
+	}
+
+	return overlay, bridge
 }

-func createAllocator(router *weave.Router, ipRangeStr string, defaultSubnetStr string, quorum uint) (*ipam.Allocator, address.CIDR) {
-	ipRange := parseAndCheckCIDR(ipRangeStr)
+func createAllocator(router *weave.NetworkRouter, config ipamConfig, db db.DB, track tracker.LocalRangeTracker, isKnownPeer func(mesh.PeerName) bool) (*ipam.Allocator, address.CIDR) {
+	ipRange, err := ipam.ParseCIDRSubnet(config.IPRangeCIDR)
+	checkFatal(err)
 	defaultSubnet := ipRange
-	if defaultSubnetStr != "" {
-		defaultSubnet = parseAndCheckCIDR(defaultSubnetStr)
+	if config.IPSubnetCIDR != "" {
+		defaultSubnet, err = ipam.ParseCIDRSubnet(config.IPSubnetCIDR)
+		checkFatal(err)
 		if !ipRange.Range().Overlaps(defaultSubnet.Range()) {
 			Log.Fatalf("IP address allocation default subnet %s does not overlap with allocation range %s", defaultSubnet, ipRange)
 		}
 	}
-	isKnownPeer := func(name weave.PeerName) bool { return router.Peers.Fetch(name) != nil }
-	allocator := ipam.NewAllocator(router.Ourself.Peer.Name, router.Ourself.Peer.UID, router.Ourself.Peer.NickName, ipRange.Range(), quorum, isKnownPeer)
+
+	c := ipam.Config{
+		OurName:     router.Ourself.Peer.Name,
+		OurUID:      router.Ourself.Peer.UID,
+		OurNickname: router.Ourself.Peer.NickName,
+		Seed:        config.SeedPeerNames,
+		Universe:    ipRange,
+		IsObserver:  config.Observer,
+		Quorum:      func() uint { return determineQuorum(config.PeerCount, router) },
+		Db:          db,
+		IsKnownPeer: isKnownPeer,
+		Tracker:     track,
+	}
+
+	allocator := ipam.NewAllocator(c)

 	allocator.SetInterfaces(router.NewGossip("IPallocation", allocator))
 	allocator.Start()
+	router.Peers.OnGC(func(peer *mesh.Peer) { allocator.PeerGone(peer.Name) })

 	return allocator, defaultSubnet
 }

-// Pick a quorum size heuristically based on the number of peer
-// addresses passed.
-func determineQuorum(initPeerCountFlag int, peers []string) uint {
+func createDNSServer(config dnsConfig, router *mesh.Router, isKnownPeer func(mesh.PeerName) bool) (*nameserver.Nameserver, *nameserver.DNSServer) {
+	ns := nameserver.New(router.Ourself.Peer.Name, config.Domain, isKnownPeer)
+	router.Peers.OnGC(func(peer *mesh.Peer) { ns.PeerGone(peer.Name) })
+	ns.SetGossip(router.NewGossip("nameserver", ns))
+	upstream := nameserver.NewUpstream(config.ResolvConf, config.EffectiveListenAddress)
+	dnsserver, err := nameserver.NewDNSServer(ns, config.Domain, config.ListenAddress,
+		upstream, uint32(config.TTL), config.ClientTimeout)
+	if err != nil {
+		Log.Fatal("Unable to start dns server: ", err)
+	}
+	listenAddr := config.ListenAddress
+	if config.EffectiveListenAddress != "" {
+		listenAddr = config.EffectiveListenAddress
+	}
+	Log.Println("Listening for DNS queries on", listenAddr)
+	return ns, dnsserver
+}
+
+// Pick a quorum size based on the number of peer addresses.
+func determineQuorum(initPeerCountFlag int, router *weave.NetworkRouter) uint {
 	if initPeerCountFlag > 0 {
 		return uint(initPeerCountFlag/2 + 1)
 	}

+	peers := router.ConnectionMaker.Targets(true)
+
 	// Guess a suitable quorum size based on the list of peer
 	// addresses.  The peer list might or might not contain an
 	// address for this peer, so the conservative assumption is
@@ -400,7 +496,65 @@ func determineQuorum(initPeerCountFlag int, peers []string) uint {
 	return quorum
 }

-func listenAndServeHTTP(httpAddr string, muxRouter *mux.Router) {
+func determinePassword(password string) []byte {
+	if password == "" {
+		password = os.Getenv("WEAVE_PASSWORD")
+	}
+	if password == "" {
+		Log.Println("Communication between peers is unencrypted.")
+		return nil
+	}
+	Log.Println("Communication between peers via untrusted networks is encrypted.")
+	return []byte(password)
+}
+
+func peerName(routerName string, iface *net.Interface) mesh.PeerName {
+	if routerName == "" {
+		if iface == nil {
+			Log.Fatal("Either an interface must be specified with --datapath or --iface, or a name with --name")
+		}
+		routerName = iface.HardwareAddr.String()
+	}
+	name, err := mesh.PeerNameFromUserInput(routerName)
+	checkFatal(err)
+	return name
+}
+
+func parseTrustedSubnets(trustedSubnetStr string) []*net.IPNet {
+	trustedSubnets := []*net.IPNet{}
+	if trustedSubnetStr == "" {
+		return trustedSubnets
+	}
+
+	for _, subnetStr := range strings.Split(trustedSubnetStr, ",") {
+		_, subnet, err := net.ParseCIDR(subnetStr)
+		if err != nil {
+			Log.Fatal("Unable to parse trusted subnets: ", err)
+		}
+		trustedSubnets = append(trustedSubnets, subnet)
+	}
+
+	return trustedSubnets
+}
+
+func parsePeerNames(s string) ([]mesh.PeerName, error) {
+	peerNames := []mesh.PeerName{}
+	if s == "" {
+		return peerNames, nil
+	}
+
+	for _, peerNameStr := range strings.Split(s, ",") {
+		peerName, err := mesh.PeerNameFromUserInput(peerNameStr)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing peer names: %s", err)
+		}
+		peerNames = append(peerNames, peerName)
+	}
+
+	return peerNames, nil
+}
+
+func listenAndServeHTTP(httpAddr string) {
 	protocol := "tcp"
 	if strings.HasPrefix(httpAddr, "/") {
 		os.Remove(httpAddr) // in case it's there from last time
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/fsouza/go-dockerclient"
+	"github.com/vishvananda/netlink"
+
+	"github.com/weaveworks/weave/common"
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+func containerAddrs(args []string) error {
+	if len(args) < 1 {
+		cmdUsage("container-addrs", "<bridgeName> [containerID ...]")
+	}
+	bridgeName := args[0]
+
+	client, err := docker.NewVersionedClientFromEnv("1.18")
+	if err != nil {
+		return err
+	}
+
+	pred, err := common.ConnectedToBridgePredicate(bridgeName)
+	if err != nil {
+		if err == weavenet.ErrLinkNotFound {
+			return nil
+		}
+		return err
+	}
+
+	var containerIDs []string
+	containers := make(map[string]*docker.Container)
+
+	for _, cid := range args[1:] {
+		if cid == "weave:expose" {
+			netDev, err := common.GetBridgeNetDev(bridgeName)
+			if err != nil {
+				return err
+			}
+			printNetDevs(cid, []common.NetDev{netDev})
+			continue
+		}
+		if containers[cid], err = client.InspectContainer(cid); err != nil {
+			if _, ok := err.(*docker.NoSuchContainer); ok {
+				continue
+			}
+			return err
+		}
+		// To output in the right order, we keep the list of container IDs
+		containerIDs = append(containerIDs, cid)
+	}
+
+	// NB: Because network namespaces (netns) are changed many times inside the loop,
+	//     it's NOT safe to exec any code depending on the root netns without
+	//     wrapping with WithNetNS*.
+	for _, cid := range containerIDs {
+		netDevs, err := getNetDevs(client, containers[cid], pred)
+		if err != nil {
+			return err
+		}
+		printNetDevs(cid, netDevs)
+	}
+
+	return nil
+}
+
+func getNetDevs(c *docker.Client, container *docker.Container, pred func(netlink.Link) bool) ([]common.NetDev, error) {
+	if container.State.Pid == 0 {
+		return nil, nil
+	}
+	return common.GetNetDevsWithPredicate(container.State.Pid, pred)
+}
+
+func printNetDevs(cid string, netDevs []common.NetDev) {
+	for _, netDev := range netDevs {
+		fmt.Printf("%12s %s %s", cid, netDev.Name, netDev.MAC.String())
+		for _, cidr := range netDev.CIDRs {
+			prefixLength, _ := cidr.Mask.Size()
+			fmt.Printf(" %v/%v", cidr.IP, prefixLength)
+		}
+		fmt.Println()
+	}
+}
@@ -0,0 +1,111 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+	"syscall"
+
+	docker "github.com/fsouza/go-dockerclient"
+	"github.com/vishvananda/netns"
+
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+func attach(args []string) error {
+	if len(args) < 4 {
+		cmdUsage("attach-container", "[--no-multicast-route] [--keep-tx-on] <container-id> <bridge-name> <mtu> <cidr>...")
+	}
+
+	keepTXOn := false
+	withMulticastRoute := true
+	for i := 0; i < len(args); {
+		switch args[i] {
+		case "--no-multicast-route":
+			withMulticastRoute = false
+			args = append(args[:i], args[i+1:]...)
+		case "--keep-tx-on":
+			keepTXOn = true
+			args = append(args[:i], args[i+1:]...)
+		default:
+			i++
+		}
+	}
+
+	pid, nsContainer, err := containerPidAndNs(args[0])
+	if err != nil {
+		return err
+	}
+	if nsHost, err := netns.GetFromPid(1); err != nil {
+		return fmt.Errorf("unable to open host namespace: %s", err)
+	} else if nsHost.Equal(nsContainer) {
+		return fmt.Errorf("Container is running in the host network namespace, and therefore cannot be\nconnected to weave. Perhaps the container was started with --net=host.")
+	}
+	mtu, err := strconv.Atoi(args[2])
+	if err != nil && args[3] != "" {
+		return fmt.Errorf("unable to parse mtu %q: %s", args[2], err)
+	}
+	cidrs, err := parseCIDRs(args[3:])
+	if err != nil {
+		return err
+	}
+
+	err = weavenet.AttachContainer(nsContainer, fmt.Sprint(pid), weavenet.VethName, args[1], mtu, withMulticastRoute, cidrs, keepTXOn)
+	// If we detected an error but the container has died, tell the user that instead.
+	if err != nil && !processExists(pid) {
+		err = fmt.Errorf("Container %s died", args[0])
+	}
+	return err
+}
+
+func containerPidAndNs(containerID string) (int, netns.NsHandle, error) {
+	c, err := docker.NewVersionedClientFromEnv("1.18")
+	if err != nil {
+		return 0, 0, fmt.Errorf("unable to connect to docker: %s", err)
+	}
+	container, err := c.InspectContainer(containerID)
+	if err != nil {
+		return 0, 0, fmt.Errorf("unable to inspect container %s: %s", containerID, err)
+	}
+	if container.State.Pid == 0 {
+		return 0, 0, fmt.Errorf("container %s not running", containerID)
+	}
+	ns, err := netns.GetFromPid(container.State.Pid)
+	if err != nil {
+		return 0, 0, fmt.Errorf("unable to open namespace for container %s: %s", containerID, err)
+	}
+	return container.State.Pid, ns, nil
+}
+
+func processExists(pid int) bool {
+	err := syscall.Kill(pid, syscall.Signal(0))
+	return err == nil || err == syscall.EPERM
+}
+
+func parseCIDRs(args []string) (cidrs []*net.IPNet, err error) {
+	for _, ipstr := range args {
+		ip, ipnet, err := net.ParseCIDR(ipstr)
+		if err != nil {
+			return nil, err
+		}
+		ipnet.IP = ip // we want the specific IP plus the mask
+		cidrs = append(cidrs, ipnet)
+	}
+	return
+}
+
+func detach(args []string) error {
+	if len(args) < 2 {
+		cmdUsage("detach-container", "<container-id> <cidr>...")
+	}
+
+	_, ns, err := containerPidAndNs(args[0])
+	if err != nil {
+		return err
+	}
+	cidrs, err := parseCIDRs(args[1:])
+	if err != nil {
+		return err
+	}
+	return weavenet.DetachContainer(ns, args[0], weavenet.VethName, cidrs)
+}
@@ -0,0 +1,52 @@
+// various fastdp operations
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/weaveworks/weave/common/odp"
+)
+
+func createDatapath(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("create-datapath", "<datapath>")
+	}
+	odpSupported, err := odp.CreateDatapath(args[0])
+	if !odpSupported {
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		}
+		// When the kernel lacks ODP support, exit with a special
+		// status to distinguish it for the weave script.
+		os.Exit(17)
+	}
+	return err
+}
+
+func deleteDatapath(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("delete-datapath", "<datapath>")
+	}
+	return odp.DeleteDatapath(args[0])
+}
+
+// Checks whether a datapath can be created by actually creating and destroying it
+func checkDatapath(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("check-datapath", "<datapath>")
+	}
+
+	if err := createDatapath(args); err != nil {
+		return err
+	}
+
+	return odp.DeleteDatapath(args[0])
+}
+
+func addDatapathInterface(args []string) error {
+	if len(args) != 2 {
+		cmdUsage("add-datapath-interface", "<datapath> <interface>")
+	}
+	return odp.AddDatapathInterface(args[0], args[1])
+}
@@ -1,26 +1,24 @@
 // docker_tls_args: find the docker daemon's tls args
-// This reimplements pgrep, because pgrep will only look in /proc, but not in
-// $PROCFS.
 package main

 import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
 )

-func main() {
-	procRoot := os.Getenv("PROCFS")
-	if procRoot == "" {
-		procRoot = "/proc"
+func dockerTLSArgs(args []string) error {
+	if len(args) > 0 {
+		cmdUsage("docker-tls-args", "")
 	}
-
+	procRoot := "/proc"
 	dirEntries, err := ioutil.ReadDir(procRoot)
-	checkErr(err)
+	if err != nil {
+		return err
+	}

 	for _, dirEntry := range dirEntries {
 		dirName := dirEntry.Name()
@@ -28,7 +26,12 @@ func main() {
 			continue
 		}

-		if comm, err := ioutil.ReadFile(filepath.Join(procRoot, dirName, "comm")); err != nil || string(comm) != "docker\n" {
+		isDaemon := false
+		if comm, err := ioutil.ReadFile(filepath.Join(procRoot, dirName, "comm")); err != nil {
+			continue
+		} else if string(comm) == "dockerd\n" {
+			isDaemon = true
+		} else if string(comm) != "docker\n" {
 			continue
 		}

@@ -37,7 +40,6 @@ func main() {
 			continue
 		}

-		isDaemon := false
 		tlsArgs := []string{}
 		args := bytes.Split(cmdline, []byte{'\000'})
 		for i := 0; i < len(args); i++ {
@@ -63,15 +65,8 @@ func main() {
 		}

 		fmt.Println(strings.Join(tlsArgs, " "))
-		os.Exit(0)
+		return nil
 	}

-	os.Exit(1)
-}
-
-func checkErr(err error) {
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+	return fmt.Errorf("cannot locate running docker daemon")
 }
@@ -0,0 +1,65 @@
+/* weaveutil: collection of operations required by weave script */
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+var commands map[string]func([]string) error
+
+func init() {
+	commands = map[string]func([]string) error{
+		"help":                   help,
+		"netcheck":               netcheck,
+		"docker-tls-args":        dockerTLSArgs,
+		"create-datapath":        createDatapath,
+		"delete-datapath":        deleteDatapath,
+		"check-datapath":         checkDatapath,
+		"add-datapath-interface": addDatapathInterface,
+		"create-plugin-network":  createPluginNetwork,
+		"remove-plugin-network":  removePluginNetwork,
+		"container-addrs":        containerAddrs,
+		"attach-container":       attach,
+		"detach-container":       detach,
+	}
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		usage()
+		os.Exit(1)
+	}
+	cmd, found := commands[os.Args[1]]
+	if !found {
+		usage()
+		os.Exit(1)
+	}
+	if err := cmd(os.Args[2:]); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func help(args []string) error {
+	if len(args) > 0 {
+		cmdUsage("help", "")
+	}
+	usage()
+	return nil
+}
+
+func usage() {
+	fmt.Fprintln(os.Stderr, "usage: weaveutil <command> <arg>...")
+	fmt.Fprintln(os.Stderr)
+	fmt.Fprintln(os.Stderr, "where <command> is one of:")
+	fmt.Fprintln(os.Stderr)
+	for cmd := range commands {
+		fmt.Fprintln(os.Stderr, cmd)
+	}
+}
+
+func cmdUsage(cmd string, usage string) {
+	fmt.Fprintf(os.Stderr, "usage: weaveutil %s %s\n", cmd, usage)
+	os.Exit(1)
+}
@@ -0,0 +1,28 @@
+/* netcheck: check whether a given network or address overlaps with any existing routes */
+package main
+
+import (
+	"net"
+
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+func netcheck(args []string) error {
+	if len(args) < 1 {
+		cmdUsage("netcheck", "<cidr> [<interface-to-ignore> ...]")
+	}
+	addr, ipnet, err := net.ParseCIDR(args[0])
+	if err != nil {
+		return err
+	}
+	ignoreIfaceNames := make(map[string]struct{})
+	for _, ifName := range args[1:] {
+		ignoreIfaceNames[ifName] = struct{}{}
+	}
+	if ipnet.IP.Equal(addr) {
+		err = weavenet.CheckNetworkFree(ipnet, ignoreIfaceNames)
+	} else {
+		err = weavenet.CheckAddressOverlap(addr, ignoreIfaceNames)
+	}
+	return err
+}
@@ -0,0 +1,86 @@
+/* various weave docker network plugin operations */
+package main
+
+import (
+	"fmt"
+
+	docker "github.com/fsouza/go-dockerclient"
+
+	"github.com/weaveworks/weave/plugin/net"
+)
+
+func createPluginNetwork(args []string) error {
+	if len(args) != 3 {
+		cmdUsage("create-plugin-network", "<network-name> <driver-name> <default-subnet>")
+	}
+	networkName := args[0]
+	driverName := args[1]
+	subnet := args[2]
+	d, err := newDockerClient()
+	if err != nil {
+		return err
+	}
+	_, err = d.CreateNetwork(
+		docker.CreateNetworkOptions{
+			Name:           networkName,
+			CheckDuplicate: true,
+			Driver:         driverName,
+			IPAM: docker.IPAMOptions{
+				Driver: driverName,
+				Config: []docker.IPAMConfig{{Subnet: subnet}},
+			},
+			Options: map[string]interface{}{plugin.MulticastOption: "true"},
+		})
+	if err != docker.ErrNetworkAlreadyExists && err != nil {
+		// Despite appearances to the contrary, CreateNetwork does
+		// sometimes(always?) *not* return ErrNetworkAlreadyExists
+		// when the network already exists. Hence we need to check for
+		// this explicitly.
+		if _, err2 := d.NetworkInfo(networkName); err2 != nil {
+			return fmt.Errorf("unable to create network: %s", err)
+		}
+	}
+	return nil
+}
+
+func removePluginNetwork(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("remove-plugin-network", "<network-name>")
+	}
+	networkName := args[0]
+	d, err := newDockerClient()
+	if err != nil {
+		return err
+	}
+	err = d.RemoveNetwork(networkName)
+	if _, ok := err.(*docker.NoSuchNetwork); !ok && err != nil {
+		if info, err2 := d.NetworkInfo(networkName); err2 == nil {
+			if len(info.Containers) > 0 {
+				containers := ""
+				for container := range info.Containers {
+					containers += fmt.Sprintf("  %.12s ", container)
+				}
+				return fmt.Errorf(`WARNING: the following containers are still attached to network %q:
+%s
+Docker operations involving those containers may pause or fail
+while Weave is not running`, networkName, containers)
+			}
+		}
+		return fmt.Errorf("unable to remove network: %s", err)
+	}
+	return nil
+}
+
+func newDockerClient() (*docker.Client, error) {
+	// API 1.21 is the first version that supports docker network
+	// commands
+	c, err := docker.NewVersionedClientFromEnv("1.21")
+	if err != nil {
+		return nil, fmt.Errorf("unable to connect to docker: %s", err)
+	}
+	_, err = c.Version()
+	if err != nil {
+		return nil, fmt.Errorf("unable to connect to docker: %s", err)
+	}
+	return c, nil
+}
@@ -1,12 +1,7 @@
-// +build !noop
+// +build !iface,!mcast

 package main

-import (
-	weavenet "github.com/weaveworks/weave/net"
-)
-
 func checkNetwork() error {
-	_, err := weavenet.EnsureInterfaceAndMcastRoute("ethwe")
-	return err
+	return nil
 }
@@ -0,0 +1,12 @@
+// +build iface,!mcast
+
+package main
+
+import (
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+func checkNetwork() error {
+	_, err := weavenet.EnsureInterface(weavenet.VethName)
+	return err
+}
@@ -0,0 +1,12 @@
+// +build iface,mcast
+
+package main
+
+import (
+	weavenet "github.com/weaveworks/weave/net"
+)
+
+func checkNetwork() error {
+	_, err := weavenet.EnsureInterfaceAndMcastRoute(weavenet.VethName)
+	return err
+}
@@ -1,7 +0,0 @@
-// +build noop
-
-package main
-
-func checkNetwork() error {
-	return nil
-}