luci-base: network.js: implement Protocol.getGateway6Addr()

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

modules/luci-base/htdocs/luci-static/resources/network.js

@@ -2158,6 +2158,27 @@ Protocol = L.Class.extend(/** @lends LuCI.Network.Protocol.prototype */ {
 		return rv;
 	},
 
+	/**
+	 * Query the gateway (nexthop) of the IPv6 default route associated with
+	 * this logical interface.
+	 *
+	 * @returns {string}
+	 * Returns a string containing the IPv6 nexthop address of the associated
+	 * default route or `null` if no default route was found.
+	 */
+	getGateway6Addr: function() {
+		var routes = this._ubus('route');
+
+		if (Array.isArray(routes))
+			for (var i = 0; i < routes.length; i++)
+				if (typeof(routes[i]) == 'object' &&
+				    routes[i].target == '::' &&
+				    routes[i].mask == 0)
+				    return routes[i].nexthop;
+
+		return null;
+	},
+
 	/**
 	 * Query the IPv6 DNS servers associated with the logical interface.
 	 *