networkd: add route expiration handler (systemd#3242)

Fix for systemd#3232.

Author: ssahani

src/network/networkd-route.c

@@ -406,15 +406,45 @@ int route_remove(Route *route, Link *link,
         return 0;
 }
 
+static int route_expire_callback(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
+        Link *link = userdata;
+        int r;
+
+        assert(rtnl);
+        assert(m);
+        assert(link);
+        assert(link->ifname);
+        assert(link->link_messages > 0);
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 1;
+
+        link->link_messages--;
+
+        r = sd_netlink_message_get_errno(m);
+        if (r < 0 && r != -EEXIST)
+                log_link_warning_errno(link, r, "could not remove route: %m");
+
+        if (link->link_messages == 0)
+                log_link_debug(link, "route removed");
+
+        return 1;
+}
+
 int route_expire_handler(sd_event_source *s, uint64_t usec, void *userdata) {
         Route *route = userdata;
         int r;
 
         assert(route);
 
-        r = route_remove(route, route->link, NULL);
+        r = route_remove(route, route->link, route_expire_callback);
         if (r < 0)
                 log_warning_errno(r, "Could not remove route: %m");
+        else {
+                /* route may not be exist in kernel. If we fail still remove it */
+                route->link->link_messages++;
+                route_free(route);
+        }
 
         return 1;
 }