application: monitor network changes, announce oneself when network becomes available

Signed-off-by: Maciek Borzecki <maciek.borzecki@gmail.com>

meson.build

@@ -23,6 +23,7 @@ add_project_arguments(['--vapidir',
 mconnect_src = [
   'src/mconnect/main.vala',
 	'src/mconnect/discovery.vala',
+	'src/mconnect/discovery-proxy.vala',
 	'src/mconnect/packet.vala',
 	'src/mconnect/device.vala',
 	'src/mconnect/discovereddevice.vala',

src/mconnect/application.vala

@@ -36,8 +36,10 @@ namespace Mconn {
 		};
 
 		private Discovery discovery = null;
+		private DiscoveryDBusProxy bus_discovery = null;
 		private DeviceManager manager = null;
 		private DeviceManagerDBusProxy bus_manager = null;
+		private NetworkMonitor net_monitor = null;
 
 		public Application() {
 			Object(application_id: "org.mconnect");
@@ -45,6 +47,7 @@ namespace Mconn {
 
 			discovery = new Discovery();
 			manager = new DeviceManager();
+			net_monitor = NetworkMonitor.get_default();
 		}
 
 		protected override void startup() {
@@ -82,6 +85,8 @@ namespace Mconn {
 			debug("activate");
 			// reload devices from cache
 			manager.load_cache();
+
+			net_monitor.network_changed.connect(this.network_changed);
 			hold();
 		}
 
@@ -91,6 +96,11 @@ namespace Mconn {
 			this.bus_manager = new DeviceManagerDBusProxy.with_manager(conn,
 																	   this.manager);
 			this.bus_manager.publish();
+
+			this.bus_discovery = new DiscoveryDBusProxy.with_discovery(conn,
+																	   this.discovery);
+			this.bus_discovery.publish();
+
 			base.dbus_register(conn, object_path);
 			debug("dbus register, path %s", object_path);
 
@@ -103,5 +113,12 @@ namespace Mconn {
 			base.dbus_unregister(conn, object_path);
 			debug("dbus unregister, path %s", object_path);
 		}
+
+		private void network_changed(Object? monitor, bool available) {
+			debug("network connectivity changed: %s", available.to_string());
+			if (available == true) {
+				this.bus_discovery.announce();
+			}
+		}
 	}
 }

src/mconnect/core.vala

@@ -29,6 +29,23 @@ class Core : Object {
 
 	public Config config { get; private set; default = null; }
 
+	public static string device_id {
+		owned get {
+			return Environment.get_host_name();
+		}
+
+		private set {}
+	}
+
+	public static string device_name {
+		owned get {
+			string host_name = Environment.get_host_name();
+			string user = Environment.get_user_name();
+			return @"$user@$host_name";
+		}
+		private set {}
+	}
+
 	private static Core _instance = null;
 
 	private Core() {
@@ -84,11 +101,9 @@ class Core : Object {
 															  "certificate.pem"));
 		if (key_file.query_exists() == false || cert_file.query_exists() == false) {
 			try {
-				string host_name = Environment.get_host_name();
-				string user = Environment.get_user_name();
 				Crypt.generate_key_cert(key_file.get_path(),
 										cert_file.get_path(),
-										@"$user@$host_name");
+										Core.device_name);
 			} catch (Error e) {
 				warning("failed to generate private key or certificate: %s", e.message);
 				throw e;

src/mconnect/device.vala

@@ -223,10 +223,8 @@ class Device : Object {
 
 	private async void greet() {
 		var core = Core.instance();
-		string host_name = Environment.get_host_name();
-		string user = Environment.get_user_name();
-		yield _channel.send(Packet.new_identity(@"$user@$host_name",
-												Environment.get_host_name(),
+		yield _channel.send(Packet.new_identity(core.device_name,
+											    core.device_id,
 												core.handlers.interfaces,
 												core.handlers.interfaces));
 

src/mconnect/discovery-proxy.vala

@@ -0,0 +1,45 @@
+/* ex:ts=4:sw=4:sts=4:et */
+/* -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * AUTHORS
+ * Maciek Borzecki <maciek.borzecki (at] gmail.com>
+ */
+
+[DBus (name = "org.mconnect.Discovery")]
+class DiscoveryDBusProxy : Object {
+
+	private Discovery discovery;
+	private const string DBUS_PATH = "/org/mconnect/discovery";
+	private DBusConnection bus = null;
+
+	public DiscoveryDBusProxy.with_discovery(DBusConnection bus,
+											 Discovery discovery) {
+		this.discovery = discovery;
+		this.bus = bus;
+	}
+
+	[DBus (visible = false)]
+	public void publish() throws IOError {
+		assert(this.bus != null);
+
+		this.bus.register_object(DBUS_PATH, this);
+
+	}
+
+	public void announce() {
+		discovery.announce();
+	}
+}

src/mconnect/discovery.vala

@@ -35,66 +35,89 @@ class Discovery : GLib.Object
 	}
 
 	public void listen() throws Error {
-			this.socket = new Socket(SocketFamily.IPV4,
-									 SocketType.DATAGRAM,
-									 SocketProtocol.UDP);
-			var sa = new InetSocketAddress(new InetAddress.any(SocketFamily.IPV4),
-										   1714);
-			debug("start listening for new devices at: %s:%u",
-				  sa.address.to_string(), sa.port);
-
-			try {
-				socket.bind(sa, false);
-			} catch (Error e) {
-				this.socket.close();
-				this.socket = null;
-				throw e;
-			}
-
-			var source = socket.create_source(IOCondition.IN);
-			source.set_callback((s, c) => {
-					this.incomingPacket();
-					return true;
-				});
-			source.attach(MainContext.default());
+		this.socket = new Socket(SocketFamily.IPV4,
+								 SocketType.DATAGRAM,
+								 SocketProtocol.UDP);
+		var sa = new InetSocketAddress(new InetAddress.any(SocketFamily.IPV4),
+									   1714);
+		debug("start listening for new devices at: %s:%u",
+			  sa.address.to_string(), sa.port);
+
+		try {
+			socket.bind(sa, false);
+		} catch (Error e) {
+			this.socket.close();
+			this.socket = null;
+			throw e;
 		}
 
+		var source = socket.create_source(IOCondition.IN);
+		source.set_callback((s, c) => {
+				this.incomingPacket();
+				return true;
+			});
+		source.attach(MainContext.default());
+	}
+
 	private void incomingPacket() {
-			vdebug("incoming packet");
+		vdebug("incoming packet");
 
-			uint8 buffer[4096];
-			SocketAddress sa;
-			InetSocketAddress isa;
+		uint8 buffer[4096];
+		SocketAddress sa;
+		InetSocketAddress isa;
 
-			try {
-				ssize_t read = this.socket.receive_from(out sa, buffer);
-				isa = (InetSocketAddress)sa;
-				vdebug("got %zd bytes from: %s:%u", read,
-						isa.address.to_string(), isa.port);
-			} catch (Error e) {
-				warning("failed to receive packet: %s", e.message);
-				return;
-			}
+		try {
+			ssize_t read = this.socket.receive_from(out sa, buffer);
+			isa = (InetSocketAddress)sa;
+			vdebug("got %zd bytes from: %s:%u", read,
+				   isa.address.to_string(), isa.port);
+		} catch (Error e) {
+			warning("failed to receive packet: %s", e.message);
+			return;
+		}
+
+		vdebug("message data: %s", (string)buffer);
 
-			vdebug("message data: %s", (string)buffer);
+		this.parsePacketFromHost((string) buffer, isa.address);
+	}
 
-			this.parsePacketFromHost((string) buffer, isa.address);
+	private void parsePacketFromHost(string data, InetAddress host) {
+		// expecing an identity packet
+		var pkt = Packet.new_from_data(data);
+		if (pkt.pkt_type != Packet.IDENTITY) {
+			message("unexpected packet type %s from device %s",
+					pkt.pkt_type, host.to_string());
+			return;
 		}
 
-	private void parsePacketFromHost(string data, InetAddress host)
-		{
-			// expecing an identity packet
-			var pkt = Packet.new_from_data(data);
-			if (pkt.pkt_type != Packet.IDENTITY) {
-				message("unexpected packet type %s from device %s",
-						pkt.pkt_type, host.to_string());
-				return;
-			}
-
-			var dev = new DiscoveredDevice.from_identity(pkt, host);
-			message("connection from device: \'%s\', responds at: %s:%u",
-				  dev.device_name, host.to_string(), dev.tcp_port);
-
-			device_found(dev);
+		var dev = new DiscoveredDevice.from_identity(pkt, host);
+		message("connection from device: \'%s\', responds at: %s:%u",
+				dev.device_name, host.to_string(), dev.tcp_port);
+
+		device_found(dev);
+	}
+
+	public void announce() {
+		var sock = new Socket(SocketFamily.IPV4,
+							  SocketType.DATAGRAM,
+							  SocketProtocol.UDP);
+		sock.broadcast = true;
+		try {
+			var sa = new InetSocketAddress(new InetAddress.from_string("255.255.255.255"),
+										   1716);
+
+			var core = Core.instance();
+
+			var identity = Packet.new_identity(core.device_name,
+											   core.device_id,
+											   core.handlers.interfaces,
+											   core.handlers.interfaces);
+
+			debug("identity: %s", identity.to_string());
+			sock.send_to(sa, identity.to_string().data);
+		} catch (Error e) {
+			warning("failed to send annoucement: %s", e.message);
 		}
+		sock.close();
+	}
 }

src/mconnect/packet.vala

@@ -132,7 +132,8 @@ class Packet : GLib.Object {
 									  string device_id,
 									  string[] in_interfaces,
 									  string[] out_interfaces,
-									  string device_type = "desktop") {
+									  string device_type = "desktop",
+									  uint tcp_port = 1716) {
 		var builder = new Json.Builder();
 		builder.begin_object();
 		builder.set_member_name("deviceName");
@@ -147,6 +148,8 @@ class Packet : GLib.Object {
 		builder.add_string_value(string.joinv(",", out_interfaces));
 		builder.set_member_name("protocolVersion");
 		builder.add_int_value(PROTOCOL_VERSION);
+		builder.set_member_name("tcpPort");
+		builder.add_int_value(tcp_port);
 		builder.end_object();
 
 		Json.Object data_obj = builder.get_root().get_object();