From 7c979d6725071c53ec0aaa9ac8ca3d190e9f37ed Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Wed, 17 Sep 2014 15:44:34 +0100
Subject: [PATCH] Remove veth and/or netns symlink if interface configuration
 fails part-way through

---
 weaver/weave | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/weaver/weave b/weaver/weave
index 8ba2b3ac..4e76309a 100755
--- a/weaver/weave
+++ b/weaver/weave
@@ -117,19 +117,28 @@ configure_container_networking() {
     [ -f /var/run/netns/$NSPID ] && rm -f /var/run/netns/$NSPID
     ln -s /proc/$NSPID/ns/net /var/run/netns/$NSPID
 
+	EXITCODE=1
     LOCAL_IFNAME="v${CONTAINER_IFNAME}pl${NSPID}"
     GUEST_IFNAME="v${CONTAINER_IFNAME}pg${NSPID}"
-    ip link add name $LOCAL_IFNAME mtu $MTU type veth peer name $GUEST_IFNAME mtu $MTU
-    ip link set $LOCAL_IFNAME master $BRIDGE
-    ip link set $LOCAL_IFNAME up
-    ip link set $GUEST_IFNAME netns $NSPID
-    ip netns exec $NSPID ip link set $GUEST_IFNAME name $CONTAINER_IFNAME
-    ip netns exec $NSPID ip addr add $2 dev $CONTAINER_IFNAME
-    ip netns exec $NSPID ip link set $CONTAINER_IFNAME up
-
-    check_command_and_run ethtool ip netns exec $NSPID ethtool -K $3 tx off >/dev/null
+    if ip link add name $LOCAL_IFNAME mtu $MTU type veth peer name $GUEST_IFNAME mtu $MTU ; then
+		if  ip link set $LOCAL_IFNAME master $BRIDGE && \
+			ip link set $LOCAL_IFNAME up && \
+			ip link set $GUEST_IFNAME netns $NSPID
+		then
+			ip netns exec $NSPID ip link set $GUEST_IFNAME name $CONTAINER_IFNAME && \
+			ip netns exec $NSPID ip addr add $2 dev $CONTAINER_IFNAME && \
+			ip netns exec $NSPID ip link set $CONTAINER_IFNAME up && \
+			$(check_command_and_run ethtool ip netns exec $NSPID ethtool -K $3 tx off >/dev/null) && \
+			EXITCODE=0
+		else
+			# failed before we assigned the veth to the container's namespace - delete it
+			ip link delete $LOCAL_IFNAME type veth || true
+		fi
+    fi
 
     [ -f /var/run/netns/$NSPID ] && rm -f /var/run/netns/$NSPID
+
+	exit $EXITCODE
 }
 
 case "$COMMAND" in