luci-base: network.js: add link status information accessors

Fixes: #5121
Fixes: 8c71b1d01e ("luci-mod-network: add port status to bridge vlan filter matrix")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

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

@@ -393,6 +393,7 @@ function initNetworkState(refresh) {
 					name:     name,
 					rawname:  name,
 					flags:    dev.flags,
+					link:     dev.link,
 					stats:    dev.stats,
 					macaddr:  dev.mac,
 					type:     dev.type,
@@ -3133,6 +3134,47 @@ Device = baseclass.extend(/** @lends LuCI.network.Device.prototype */ {
 		return (stat != null ? stat.rx_packets || 0 : 0);
 	},
 
+	/**
+	 * Get the carrier state of the network device.
+	 *
+	 * @returns {boolean}
+	 * Returns true if the device has a carrier, e.g. when a cable is
+	 * inserted into an ethernet port of false if there is none.
+	 */
+	getCarrier: function() {
+		var link = this._devstate('link');
+		return (link != null ? link.carrier || false : false);
+	},
+
+	/**
+	 * Get the current link speed of the network device if available.
+	 *
+	 * @returns {number|null}
+	 * Returns the current speed of the network device in Mbps. If the
+	 * device supports no ethernet speed levels, null is returned.
+	 * If the device supports ethernet speeds but has no carrier, -1 is
+	 * returned.
+	 */
+	getSpeed: function() {
+		var link = this._devstate('link');
+		return (link != null ? link.speed || null : null);
+	},
+
+	/**
+	 * Get the current duplex mode of the network device if available.
+	 *
+	 * @returns {string|null}
+	 * Returns the current duplex mode of the network device. Returns
+	 * either "full" or "half" if the device supports duplex modes or
+	 * null if the duplex mode is unknown or unsupported.
+	 */
+	getDuplex: function() {
+		var link = this._devstate('link'),
+		    duplex = link ? link.duplex : null;
+
+		return (duplex != 'unknown') ? duplex : null;
+	},
+
 	/**
 	 * Get the primary logical interface this device is assigned to.
 	 *