set http listen address solely through the weave script

Previously it was set by the script only in fastdp mode; and in the
router's main.go otherwise. Yet every interaction of the script with
weave assumes the port is the script's HTTP_PORT=6784. By always
starting the router with options to listen on that port we ensure that
the router is in fact listening where the script expects it to.

In doing this get rid of router.HTTPPort. We do need to hard-code the
port in the proxy instead, but relying on router.HTTPPort was flawed
anyway, for the above reasons.

prog/weaver/main.go

@@ -85,7 +85,7 @@ 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(&httpAddr, []string{"#httpaddr", "#-httpaddr", "-http-addr"}, "", "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)")

proxy/proxy.go

@@ -17,7 +17,6 @@ import (
 	. "github.com/weaveworks/weave/common"
 	weavedocker "github.com/weaveworks/weave/common/docker"
 	"github.com/weaveworks/weave/nameserver"
-	"github.com/weaveworks/weave/router"
 )
 
 const (
@@ -490,7 +489,7 @@ func (proxy *Proxy) getDNSDomain() (domain string) {
 		weaveIP = "127.0.0.1"
 	}
 
-	url := fmt.Sprintf("http://%s:%d/domain", weaveIP, router.HTTPPort)
+	url := fmt.Sprintf("http://%s:6784/domain", weaveIP)
 	resp, err := http.Get(url)
 	if err != nil || resp.StatusCode != http.StatusOK {
 		return

router/router.go

@@ -12,7 +12,6 @@ import (
 
 const (
 	Port                = 6783
-	HTTPPort            = Port + 1
 	MaxUDPPacketSize    = 65535
 	ChannelSize         = 16
 	TCPHeartbeat        = 30 * time.Second

weave

@@ -1463,6 +1463,7 @@ launch_router() {
 
     if [ "$BRIDGE_TYPE" = fastdp ] ; then
         NETHOST_OPT="--net=host"
+        HTTP_IP=127.0.0.1
         # In case there is a lingering veth-weave netdev
         ip link del $ROUTER_HOSTNETNS_IFNAME >/dev/null 2>&1 || true
     fi
@@ -1481,7 +1482,8 @@ launch_router() {
         $(router_opts_$BRIDGE_TYPE) \
         --ipalloc-range "$IPRANGE" \
         --dns-effective-listen-address $DOCKER_BRIDGE_IP \
-        ${NETHOST_OPT:+$DNS_ROUTER_OPTS --http-addr 127.0.0.1:$HTTP_PORT} $NO_DNS_OPT \
+        ${NETHOST_OPT:+$DNS_ROUTER_OPTS} $NO_DNS_OPT \
+        --http-addr $HTTP_IP:$HTTP_PORT \
         --docker-api "unix:///var/run/docker.sock" "$@")
     with_container_netns_or_die $CONTAINER_NAME setup_router_iface_$BRIDGE_TYPE
     attach_router