Update route metric before sending the Sync message

network/default.go

@@ -1293,6 +1293,20 @@ func (n *network) getProtoRoutes() ([]*pbRtr.Route, error) {
 	// encode the routes to protobuf
 	pbRoutes := make([]*pbRtr.Route, 0, len(routes))
 	for _, route := range routes {
+		// calculate route metric and add to the advertised metric
+		// we need to make sure we do not overflow math.MaxInt64
+		metric := n.getRouteMetric(route.Router, route.Gateway, route.Link)
+		log.Tracef("Network metric for router %s and gateway %s: %v", route.Router, route.Gateway, metric)
+
+		// check we don't overflow max int 64
+		if d := route.Metric + metric; d <= 0 {
+			// set to max int64 if we overflow
+			route.Metric = math.MaxInt64
+		} else {
+			// set the combined value of metrics otherwise
+			route.Metric = d
+		}
+
 		// generate new route proto
 		pbRoute := pbUtil.RouteToProto(route)
 		// mask the route before outbounding