iptables rule to drop traffic from docker0 bridge to weave bridge

weave

@@ -260,6 +260,8 @@ create_bridge() {
         ip link add name v${CONTAINER_IFNAME}du mtu $MTU type dummy
         ip link set dev v${CONTAINER_IFNAME}du master $BRIDGE
         ip link del dev v${CONTAINER_IFNAME}du
+        # Drop traffic from Docker bridge to Weave; it can break subnet isolation
+        run_iptables -t filter -I FORWARD -i $DOCKER_BRIDGE -o $BRIDGE -j DROP
         # Work around the situation where there are no rules allowing traffic
         # across our bridge. E.g. ufw
         add_iptables_rule filter FORWARD -i $BRIDGE -o $BRIDGE -j ACCEPT
@@ -282,6 +284,7 @@ destroy_bridge() {
     if [ -d /sys/class/net/$BRIDGE ] ; then
         ip link del dev $BRIDGE
     fi
+    run_iptables -t filter -D FORWARD -i $DOCKER_BRIDGE -o $BRIDGE -j DROP 2>/dev/null || true
     run_iptables -t filter -D FORWARD -i $BRIDGE -o $BRIDGE -j ACCEPT 2>/dev/null || true
     run_iptables -t nat -F WEAVE >/dev/null 2>&1 || true
     run_iptables -t nat -D POSTROUTING -j WEAVE >/dev/null 2>&1 || true