Merge branch '1.9'

net/veth.go

@@ -106,7 +106,7 @@ func interfaceExistsInNamespace(netNSPath string, ifName string) bool {
 
 // NB: This function can be used only by a process that terminates immediately
 //     after calling the function as it changes netns via WithNetNSLinkUnsafe.
-func AttachContainer(netNSPath, id, ifName, bridgeName string, mtu int, withMulticastRoute bool, cidrs []*net.IPNet, keepTXOn bool) error {
+func AttachContainer(netNSPath, id, ifName, bridgeName string, mtu int, withMulticastRoute bool, cidrs []*net.IPNet, keepTXOn bool, hairpinMode bool) error {
 	ns, err := netns.GetFromPath(netNSPath)
 	if err != nil {
 		return err
@@ -124,7 +124,7 @@ func AttachContainer(netNSPath, id, ifName, bridgeName string, mtu int, withMult
 			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 {
+		veth, 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)
 			}
@@ -136,6 +136,10 @@ func AttachContainer(netNSPath, id, ifName, bridgeName string, mtu int, withMult
 		if err != nil {
 			return err
 		}
+		if err = netlink.LinkSetHairpin(veth, hairpinMode); err != nil {
+			return fmt.Errorf("unable to set hairpin mode to %t for bridge side of veth %s: %s", hairpinMode, name, err)
+		}
+
 	}
 
 	if err := WithNetNSLinkUnsafe(ns, ifName, func(veth netlink.Link) error {

plugin/net/cni.go

@@ -34,7 +34,8 @@ func NewCNIPlugin(weave *weaveapi.Client) *CNIPlugin {
 
 func loadNetConf(bytes []byte) (*NetConf, error) {
 	n := &NetConf{
-		BrName: weavenet.WeaveBridgeName,
+		BrName:      weavenet.WeaveBridgeName,
+		HairpinMode: true,
 	}
 	if err := json.Unmarshal(bytes, n); err != nil {
 		return nil, fmt.Errorf("failed to load netconf: %v", err)
@@ -128,7 +129,7 @@ func (c *CNIPlugin) CmdAdd(args *skel.CmdArgs) error {
 		id = fmt.Sprintf("%x", data)
 	}
 
-	if err := weavenet.AttachContainer(args.Netns, id, args.IfName, conf.BrName, conf.MTU, false, []*net.IPNet{&ip.Address}, false); err != nil {
+	if err := weavenet.AttachContainer(args.Netns, id, args.IfName, conf.BrName, conf.MTU, false, []*net.IPNet{&ip.Address}, false, conf.HairpinMode); err != nil {
 		return err
 	}
 	if err := weavenet.WithNetNSLinkUnsafe(ns, args.IfName, func(link netlink.Link) error {
@@ -218,8 +219,9 @@ func logOnStderr(err error) {
 
 type NetConf struct {
 	types.NetConf
-	BrName string `json:"bridge"`
+	BrName      string `json:"bridge"`
-	IsGW   bool   `json:"isGateway"`
+	IsGW        bool   `json:"isGateway"`
-	IPMasq bool   `json:"ipMasq"`
+	IPMasq      bool   `json:"ipMasq"`
-	MTU    int    `json:"mtu"`
+	MTU         int    `json:"mtu"`
+	HairpinMode bool   `json:"hairpinMode"`
 }

prog/weaveutil/attach.go

@@ -17,11 +17,12 @@ import (
 
 func attach(args []string) error {
 	if len(args) < 4 {
-		cmdUsage("attach-container", "[--no-multicast-route] [--keep-tx-on] <container-id> <bridge-name> <mtu> <cidr>...")
+		cmdUsage("attach-container", "[--no-multicast-route] [--keep-tx-on] [--hairpin-mode=true|false] <container-id> <bridge-name> <mtu> <cidr>...")
 	}
 
 	keepTXOn := false
 	withMulticastRoute := true
+	hairpinMode := true
 	for i := 0; i < len(args); {
 		switch args[i] {
 		case "--no-multicast-route":
@@ -30,6 +31,9 @@ func attach(args []string) error {
 		case "--keep-tx-on":
 			keepTXOn = true
 			args = append(args[:i], args[i+1:]...)
+		case "--hairpin-mode=false":
+			hairpinMode = false
+			args = append(args[:i], args[i+1:]...)
 		default:
 			i++
 		}
@@ -58,7 +62,7 @@ func attach(args []string) error {
 		return err
 	}
 
-	err = weavenet.AttachContainer(weavenet.NSPathByPid(pid), fmt.Sprint(pid), weavenet.VethName, args[1], mtu, withMulticastRoute, cidrs, keepTXOn)
+	err = weavenet.AttachContainer(weavenet.NSPathByPid(pid), fmt.Sprint(pid), weavenet.VethName, args[1], mtu, withMulticastRoute, cidrs, keepTXOn, hairpinMode)
 	// 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])

proxy/proxy.go

@@ -515,7 +515,7 @@ func (proxy *Proxy) attach(containerID string) error {
 
 	pid := container.State.Pid
 	// Passing 0 for mtu means it will be taken from the bridge
-	err = weavenet.AttachContainer(weavenet.NSPathByPid(pid), fmt.Sprint(pid), weavenet.VethName, weavenet.WeaveBridgeName, 0, !proxy.NoMulticastRoute, ips, proxy.KeepTXOn)
+	err = weavenet.AttachContainer(weavenet.NSPathByPid(pid), fmt.Sprint(pid), weavenet.VethName, weavenet.WeaveBridgeName, 0, !proxy.NoMulticastRoute, ips, proxy.KeepTXOn, true)
 	if err != nil {
 		return err
 	}

site/kube-addon.md

@@ -221,6 +221,10 @@ The list of variables you can set is:
 
 * `CHECKPOINT_DISABLE` - if set to 1, disable checking for new Weave Net
   versions (default is blank, i.e. check is enabled)
+* `HAIRPIN_MODE` - Weave Net defaults to enabling hairpin on the bridge side of
+  the `veth` pair for containers attached. If you need to disable hairpin, e.g. your
+  kernel is one of those that can panic if hairpin is enabled, then you can disable it
+  by setting `HAIRPIN_MODE=false`.
 * `IPALLOC_RANGE` - the range of IP addresses used by Weave Net
   and the subnet they are placed in (CIDR format; default `10.32.0.0/12`)
 * `EXPECT_NPC` - set to 0 to disable Network Policy Controller (default is on)

test/830_cni_plugin_test.sh

@@ -8,7 +8,7 @@ cni_connect() {
     pid=$(container_pid $1 $2)
     id=$(docker_on $1 inspect -f '{{.Id}}' $2)
     run_on $1 sudo CNI_COMMAND=ADD CNI_CONTAINERID=$id CNI_IFNAME=eth0 \
-    CNI_NETNS=/proc/$pid/ns/net CNI_PATH=/opt/cni/bin /opt/cni/bin/weave-net 
+    CNI_NETNS=/proc/$pid/ns/net CNI_PATH=/opt/cni/bin /opt/cni/bin/weave-net
 }
 
 run_on $HOST1 sudo mkdir -p /opt/cni/bin
@@ -19,6 +19,11 @@ weave_on $HOST1 launch
 C0=$(docker_on $HOST1 run --net=none --name=c0 -dt $SMALL_IMAGE /bin/sh)
 C1=$(docker_on $HOST1 run --net=none --privileged --name=c1 -dt $SMALL_IMAGE /bin/sh)
 C2=$(docker_on $HOST1 run --net=none --name=c2 -dt $SMALL_IMAGE /bin/sh)
+CH0=$(docker_on $HOST1 run --net=none --name=ch0 -dt $SMALL_IMAGE /bin/sh)
+CH1=$(docker_on $HOST1 run --net=none --name=ch1 -dt $SMALL_IMAGE /bin/sh)
+CH2=$(docker_on $HOST1 run --net=none --name=ch2 -dt $SMALL_IMAGE /bin/sh)
+
+
 # Enable unsolicited ARPs so that ping after the address reuse does not time out
 exec_on $HOST1 c1 sysctl -w net.ipv4.conf.all.arp_accept=1
 
@@ -52,6 +57,29 @@ cni_connect $HOST1 c2 <<EOF
 }
 EOF
 
+# examples to test hairpin
+cni_connect $HOST1 ch0 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net",
+    "hairpinMode": true
+}
+EOF
+cni_connect $HOST1 ch1 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net",
+    "hairpinMode": false
+}
+EOF
+cni_connect $HOST1 ch2 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net"
+}
+EOF
+
+
 C0IP=$(container_ip $HOST1 c0)
 C1IP=$(container_ip $HOST1 c1)
 C2IP=$(container_ip $HOST1 c2)
@@ -85,6 +113,29 @@ assert_raises "[ $C2IP != $C3IP ]"
 assert_raises "[ $BRIP != $C3IP ]"
 assert_raises "exec_on $HOST1 c1 $PING $C3IP"
 
+#####
+#
+# Hairpin mode tests
+#
+# here we check that the bridge side of the veth is set to hairpin mode (true or false) correctly
+# check for each of
+# - ch0 explicitly true
+# - ch1 explicitly false
+# - ch2 unset, which should default to true
+#
+# we take advantage of the veth name being constructed from the container ID)
+#
+# should this reliance ever fail and we need to get it from the system, do the following for each:
+# CH0_PEER_ID=$(exec_on $HOST1 ch0 cat /sys/class/net/eth0/iflink)
+# CH0_PEER=$($SSH $HOST1 ip link show | awk "/^${CH0_PEER_ID}:/"' {print $2}' | sed 's/@.*$//g' )
+# CH0_HAIRPIN=$($SSH $HOST1 cat /sys/devices/virtual/net/weave/brif/$CH0_PEER/hairpin_mode)
+# assert_raises "[ $CH0_HAIRPIN == 1 ]"
+#
+assert "$SSH $HOST1 cat /sys/devices/virtual/net/weave/brif/vethwepl${CH0:0:7}/hairpin_mode" "1"
+assert "$SSH $HOST1 cat /sys/devices/virtual/net/weave/brif/vethwepl${CH1:0:7}/hairpin_mode" "0"
+assert "$SSH $HOST1 cat /sys/devices/virtual/net/weave/brif/vethwepl${CH2:0:7}/hairpin_mode" "1"
+
+
 
 # Ensure existing containers can reclaim their IP addresses after CNI has been used -- see #2548
 stop_weave_on $HOST1

weave

@@ -745,17 +745,20 @@ create_cni_config() {
     cat >"$1" <<EOF
 {
     "name": "weave",
-    "type": "weave-net"
+    "type": "weave-net",
+    "hairpinMode": $2
 }
 EOF
 }
 
 setup_cni() {
+    # if env var HAIRPIN_MODE is not set, default it to true
+    HAIRPIN_MODE=${HAIRPIN_MODE:-true}
     if install_cni_plugin $CNI_PLUGIN_DIR ; then
         upgrade_cni_plugin $CNI_PLUGIN_DIR
     fi
     if [ -d $HOST_ROOT/etc/cni/net.d -a ! -f $HOST_ROOT/etc/cni/net.d/10-weave.conf ] ; then
-        create_cni_config $HOST_ROOT/etc/cni/net.d/10-weave.conf
+        create_cni_config $HOST_ROOT/etc/cni/net.d/10-weave.conf $HAIRPIN_MODE
     fi
 }