weave run and weave attach accept --no-multicast-route

weave

@@ -59,7 +59,8 @@ weave connect       [--replace] [<peer> ...]
 weave forget        <peer> ...
 weave status        [targets | connections | peers | dns]
 weave report        [-f <format>]
-weave run           [--with-dns | --without-dns] [--no-rewrite-hosts]
+weave run           [--with-dns | --without-dns]
+                    [--no-rewrite-hosts] [--no-multicast-route]
                       [<addr> ...] <docker run args> ...
 weave start         [<addr> ...] <container_id>
 weave attach        [<addr> ...] <container_id>
@@ -258,20 +259,42 @@ elif [ "$1" = "run" -a -z "$IS_LOCAL" ] ; then
     # because we are passing arbitrary arguments on to docker run, and
     # we can't rely on our baked-in docker to support those arguments.
     shift 1
+
     if [ "$1" != "--without-dns" ] ; then
         DNS_ARGS=$(exec_remote dns-args "$@" || true)
     fi
     shift $(dns_arg_count "$@")
-    if [ "$1" = "--no-rewrite-hosts" ] ; then
+
+    REWRITE_HOSTS=1
+    NO_MULTICAST_ROUTE=
+    while [ $# -gt 0 ]; do
+        case "$1" in
+            --no-rewrite-hosts)
+                REWRITE_HOSTS=
+                ;;
+            --no-multicast-route)
+                NO_MULTICAST_ROUTE=1
+                ;;
+            *)
+                break
+                ;;
+        esac
         shift
-    else
+    done
+
+    if [ -n "$REWRITE_HOSTS" ] ; then
         extra_hosts_args "$@"
         DNS_EXTRA_HOSTS_ARGS="--rewrite-hosts $DNS_EXTRA_HOSTS_ARGS"
     fi
+
+    if [ -n "$NO_MULTICAST_ROUTE" ] ; then
+        ATTACH_ARGS="--no-multicast-route"
+    fi
+
     collect_cidr_args "$@"
     shift $CIDR_ARG_COUNT
     CONTAINER=$(docker $DOCKER_CLIENT_ARGS run -e WEAVE_CIDR=none $DNS_ARGS -d "$@")
-    exec_remote attach $CIDR_ARGS --or-die $DNS_EXTRA_HOSTS_ARGS $CONTAINER >/dev/null
+    exec_remote attach $CIDR_ARGS --or-die $DNS_EXTRA_HOSTS_ARGS $ATTACH_ARGS $CONTAINER >/dev/null
     echo $CONTAINER
     exit 0
 fi
@@ -841,8 +864,10 @@ attach() {
     # 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.
-    if ! netnsenter ip route show | grep '^224\.0\.0\.0/4' >/dev/null ; then
-        netnsenter ip route add 224.0.0.0/4 dev $CONTAINER_IFNAME mtu lock $MTU
+    if [ -z "$NO_MULTICAST_ROUTE" ] ; then
+        if ! netnsenter ip route show | grep '^224\.0\.0\.0/4' >/dev/null ; then
+            netnsenter ip route add 224.0.0.0/4 dev $CONTAINER_IFNAME mtu lock $MTU
+        fi
     fi
 }
 
@@ -1914,10 +1939,21 @@ EOF
         dns_args "$@"
         shift $(dns_arg_count "$@")
         REWRITE_HOSTS=1
-        if [ "$1" = "--no-rewrite-hosts" ] ; then
-            REWRITE_HOSTS=
+        NO_MULTICAST_ROUTE=
+        while [ $# -gt 0 ]; do
+            case "$1" in
+                --no-rewrite-hosts)
+                    REWRITE_HOSTS=
+                    ;;
+                --no-multicast-route)
+                    NO_MULTICAST_ROUTE=1
+                    ;;
+                *)
+                    break
+                    ;;
+            esac
             shift
-        fi
+        done
         collect_cidr_args "$@"
         shift $CIDR_ARG_COUNT
         CONTAINER=$(docker run -e WEAVE_CIDR=none $DNS_ARGS -d "$@")
@@ -1954,6 +1990,7 @@ EOF
     attach)
         DNS_EXTRA_HOSTS=
         REWRITE_HOSTS=
+        NO_MULTICAST_ROUTE=
         collect_cidr_args "$@"
         shift $CIDR_ARG_COUNT
         while [ $# -gt 0 ]; do
@@ -1971,6 +2008,9 @@ EOF
                 --add-host=*)
                     DNS_EXTRA_HOSTS="${1#*=} $DNS_EXTRA_HOSTS"
                     ;;
+                --no-multicast-route)
+                    NO_MULTICAST_ROUTE=1
+                    ;;
                 *)
                     break
                     ;;