Move AWSVPC sysctls into Go code

net/bridge.go

@@ -228,6 +228,18 @@ func CreateBridge(config *BridgeConfig) (BridgeType, error) {
 
 	if config.IsAWSVPC {
 		bridgeType = AWSVPC
+		// Set proxy_arp on the bridge, so that it could accept packets destined
+		// to containers within the same subnet but running on remote hosts.
+		// Without it, exact routes on each container are required.
+		if err := sysctl("net/ipv4/conf/"+config.WeaveBridgeName+"/proxy_arp", "1"); err != nil {
+			return bridgeType, errors.Wrap(err, "setting proxy_arp")
+		}
+		// Avoid delaying the first ARP request. Also, setting it to 0 avoids
+		// placing the request into a bounded queue as it can be seen:
+		// https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/net/ipv4/arp.c?id=refs/tags/v4.6.1#n819
+		if err := sysctl("net/ipv4/neigh/"+config.WeaveBridgeName+"/proxy_delay", "0"); err != nil {
+			return bridgeType, errors.Wrap(err, "setting proxy_arp")
+		}
 	}
 
 	if bridgeType == Bridge {

weave

@@ -1427,14 +1427,6 @@ launch_router() {
 
 setup_awsvpc() {
     if [ -n "$AWSVPC" ]; then
-        # Set proxy_arp on the bridge, so that it could accept packets destined
-        # to containers within the same subnet but running on remote hosts.
-        # Without it, exact routes on each container are required.
-        echo 1 >$PROC_PATH/sys/net/ipv4/conf/$BRIDGE/proxy_arp
-        # Avoid delaying the first ARP request. Also, setting it to 0 avoids
-        # placing the request into a bounded queue as it can be seen:
-        # https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/net/ipv4/arp.c?id=refs/tags/v4.6.1#n819
-        echo 0 >$PROC_PATH/sys/net/ipv4/neigh/$BRIDGE/proxy_delay
         expose_ip
     fi
 }