wireguard: add metric to routes

maintainer: Felix Fietkau <nbd@nbd.name>

The metric field is not used when wireGuard routes are created.

See: https://github.com/openwrt/openwrt/issues/23199

This patch is aimed at adding the metric field in the config to the created routes for WireGuard if
the metric field is not empty and not 0

Compile tested: X86, Openwrt-main
Run tested: X86

Please have a look and consider implementing

Signed-off-by: Erik Conijn <egc112@msn.com>
Link: https://github.com/openwrt/openwrt/pull/23280
Signed-off-by: Robert Marko <robimarko@gmail.com>

package/network/utils/wireguard-tools/files/wireguard.uc

@@ -111,6 +111,8 @@ function proto_setup(proto) {
 	if (config.fwmark)
 		wg_config += sprintf('FwMark=%s\n', config.fwmark);
 
+	let metric = int(config.metric);
+
 	let ipv4_routes = [];
 	let ipv6_routes = [];
 
@@ -136,6 +138,8 @@ function proto_setup(proto) {
 				for (let allowed_ip in allowed_list) {
 					let addr_info = parse_address(allowed_ip);
 					let route = { target: addr_info.address, netmask: '' + addr_info.mask };
+					if (metric)
+						route.metric = metric;
 					if (addr_info.family == 6)
 						push(ipv6_routes, route);
 					else