Merge branch '1.1'

test/170_ip_reuse_test.sh

@@ -0,0 +1,31 @@
+#! /bin/bash
+
+. ./config.sh
+
+C1=10.2.1.43
+C2=10.2.1.44
+C3=10.2.1.45
+
+start_suite "re-using IP addresses (arp cache updating)"
+
+weave_on $HOST1 launch
+
+check() {
+    assert_raises "exec_on $HOST1 c1 $PING $C2"
+}
+
+start_container $HOST1 $C1/24 --name=c1
+
+start_container $HOST1 $C2/24 --name=c2
+check
+
+docker_on $HOST1 stop c2
+start_container $HOST1 $C2/24 --name=c3
+check
+
+docker_on $HOST1 stop c3
+start_container $HOST1 $C3/24 --name=c4
+weave_on $HOST1 attach $C2/24 c4
+check
+
+end_suite

weave

@@ -521,31 +521,27 @@ launch() {
 }
 
 attach() {
-    if netnsenter ip link show $CONTAINER_IFNAME >/dev/null 2>&1 ; then
-        for ADDR in "$@" ; do
-            # container already has the expected network interface, so assume we set it up already;
-            # just add the IP address.
-            if netnsenter ip addr show dev $CONTAINER_IFNAME | grep -F $ADDR >/dev/null ; then
-                # address was there already
-                continue
-            fi
-            netnsenter ip addr add $ADDR dev $CONTAINER_IFNAME || return 1
-        done
-
-        return 0
+    if ! netnsenter ip link show $CONTAINER_IFNAME >/dev/null 2>&1 ; then
+        connect_container_to_bridge || return 1
     fi
 
-    connect_container_to_bridge || return 1
-
+    NEW_ADDRS=
     for ADDR in "$@" ; do
+        if netnsenter ip addr show dev $CONTAINER_IFNAME | grep -F $ADDR >/dev/null ; then
+            # address was there already
+            continue
+        fi
         netnsenter ip addr add $ADDR dev $CONTAINER_IFNAME || return 1
+        NEW_ADDRS="$NEW_ADDRS $ADDR"
     done
 
     netnsenter ip link set $CONTAINER_IFNAME up || return 1
 
-    for ADDR in "$@" ; do
-        arp_update $CONTAINER_IFNAME $ADDR "netnsenter"
-    done
+    if [ -n "$NEW_ADDRS" ] ; then
+        for ADDR in "$NEW_ADDRS" ; do
+            arp_update $CONTAINER_IFNAME $ADDR "netnsenter"
+        done
+    fi
 
     # Route multicast packets across the weave network.
     # This must come last in 'attach'. If you change this, change weavewait to match.