Enable callers to pass the source IP of an IPv4 route when using

proto_add_ipv4_route(). This is useful with for example DHCP in a multihomed
scenario, as it provides an easy way to match default routes with the correct IP
address. One use case for this are applications that monitor the state of the
WAN port, and the WAN port is assigned multiple addresses.

Signed-off-by: Kristian Evensen <kristian.evensen at gmail.com>

scripts/netifd-proto.sh

@@ -120,8 +120,9 @@ proto_add_ipv4_route() {
 	local target="$1"
 	local mask="$2"
 	local gw="$3"
+	local source="$4"
 
-	append PROTO_ROUTE "$target/$mask/$gw//"
+	append PROTO_ROUTE "$target/$mask/$gw///$source"
 }
 
 proto_add_ipv6_route() {