Merge remote-tracking branch 'upstream/master' into 67_attach

README.md

@@ -483,10 +483,14 @@ connected to the bridge is the weave router container, which is given
 the IP address & netmask supplied in 'weave launch'.
 
 A weave router captures Ethernet packets from its bridge-connected
-interface in promiscuous mode, using 'pcap'. It forwards these packets
-over UDP to weave router peers running on other hosts. On receipt of
-such a packet, a router injects the packet on its bridge interface
-using 'pcap' and/or forwards the packet to peers.
+interface in promiscuous mode, using 'pcap'. This typically excludes
+traffic between local containers, and between the host and local
+containers, all of which is routed straight over the bridge by the
+kernel. Captured packets are forwarded over UDP to weave router peers
+running on other hosts. On receipt of such a packet, a router injects
+the packet on its bridge interface using 'pcap' and/or forwards the
+packet to peers.
+
 
 Weave routers learn which peer host a particular MAC address resides
 on. They combine this knowledge with topology information in order to

pcap.go

@@ -8,9 +8,19 @@ type PcapIO struct {
 	handle *pcap.Handle
 }
 
-func NewPcapIO(ifName string, bufSz int) (pio PacketSourceSink, err error) {
-	pio, err = newPcapIO(ifName, true, 65535, bufSz)
-	return
+func NewPcapIO(ifName string, bufSz int) (PacketSourceSink, error) {
+	pio, err := newPcapIO(ifName, true, 65535, bufSz)
+	if err != nil {
+		return pio, err
+	}
+
+	// Under Linux, libpcap implements the SetDirection filtering
+	// in userspace.  So set a BPF filter to discard outbound
+	// packets inside the kernel.  We do this here rather than in
+	// newPcapIO because libpcap doesn't like this in combination
+	// with a 0 snaplen.
+	err = pio.handle.SetBPFFilter("inbound")
+	return pio, err
 }
 
 func NewPcapO(ifName string) (po PacketSink, err error) {

weaver/weave

@@ -115,22 +115,43 @@ configure_container_networking() {
     NSPID=$DOCKERPID
 
     [ ! -d /var/run/netns ] && mkdir -p /var/run/netns
-    [ -f /var/run/netns/$NSPID ] && rm -f /var/run/netns/$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
+    IP_TMPFILE=/tmp/weave_ip_output_$$
+    rm -f $IP_TMPFILE
+    if ip link add name $LOCAL_IFNAME mtu $MTU type veth peer name $GUEST_IFNAME mtu $MTU >$IP_TMPFILE 2>&1 ; then
+        if  (ip link set $LOCAL_IFNAME master $BRIDGE &&
+                ip link set $LOCAL_IFNAME up &&
+                ip link set $GUEST_IFNAME netns $NSPID) >$IP_TMPFILE 2>&1
+        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 $3 tx off >/dev/null) >$IP_TMPFILE 2>&1 &&
+            EXITCODE=0
+        else
+            # failed before we assigned the veth to the container's namespace - delete it
+            ip link del $LOCAL_IFNAME type veth || true
+        fi
+    fi
 
-    check_command_and_run ethtool ip netns exec $NSPID ethtool -K $3 tx off >/dev/null
+    if [ "$EXITCODE" -ne 0 ] ; then
+        if ! ps -p $DOCKERPID >/dev/null 2>&1 ; then
+            echo "Container $1 died" >&2
+        else
+            echo "Failure during network configuration for container $1:" >&2
+            cat $IP_TMPFILE >&2
+        fi
+    fi
 
-    [ -f /var/run/netns/$NSPID ] && rm -f /var/run/netns/$NSPID
+    rm -f $IP_TMPFILE
+    rm -f /var/run/netns/$NSPID
+
+    return $EXITCODE
 }
 
 case "$COMMAND" in