Added get_port() method to socket_t to learn the listening port.

src/libcharon/plugins/socket_default/socket_default_socket.c

@@ -305,7 +305,7 @@ METHOD(socket_t, sender, status_t,
 	/* send data */
 	sport = src->get_port(src);
 	family = dst->get_family(dst);
-	if (sport == CHARON_UDP_PORT)
+	if (sport == 0 || sport == CHARON_UDP_PORT)
 	{
 		if (family == AF_INET)
 		{
@@ -405,6 +405,12 @@ METHOD(socket_t, sender, status_t,
 	return SUCCESS;
 }
 
+METHOD(socket_t, get_port, u_int16_t,
+	private_socket_default_socket_t *this, bool nat_t)
+{
+	return nat_t ? CHARON_NATT_PORT : CHARON_UDP_PORT;
+}
+
 /**
  * open a socket to send and receive packets
  */
@@ -533,6 +539,7 @@ socket_default_socket_t *socket_default_socket_create()
 			.socket = {
 				.send = _sender,
 				.receive = _receiver,
+				.get_port = _get_port,
 				.destroy = _destroy,
 			},
 		},

src/libcharon/plugins/socket_dynamic/socket_dynamic_socket.c

@@ -467,6 +467,7 @@ METHOD(socket_t, sender, status_t,
 	dst = packet->get_destination(packet);
 	family = src->get_family(src);
 	port = src->get_port(src);
+	port = port ?: CHARON_UDP_PORT;
 	skt = find_socket(this, family, port);
 	if (!skt)
 	{
@@ -534,6 +535,14 @@ METHOD(socket_t, sender, status_t,
 	return SUCCESS;
 }
 
+METHOD(socket_t, get_port, u_int16_t,
+	private_socket_dynamic_socket_t *this, bool nat_t)
+{
+	/* we return 0 here for users that have no explicit port configured, the
+	 * sender will default to the default port in this case */
+	return 0;
+}
+
 METHOD(socket_t, destroy, void,
 	private_socket_dynamic_socket_t *this)
 {
@@ -567,6 +576,7 @@ socket_dynamic_socket_t *socket_dynamic_socket_create()
 			.socket = {
 				.send = _sender,
 				.receive = _receiver,
+				.get_port = _get_port,
 				.destroy = _destroy,
 			},
 		},

src/libcharon/plugins/socket_raw/socket_raw_socket.c

@@ -309,7 +309,7 @@ METHOD(socket_t, sender, status_t,
 	/* send data */
 	sport = src->get_port(src);
 	family = dst->get_family(dst);
-	if (sport == CHARON_UDP_PORT)
+	if (sport == 0 || sport == CHARON_UDP_PORT)
 	{
 		if (family == AF_INET)
 		{
@@ -470,6 +470,12 @@ static int open_send_socket(private_socket_raw_socket_t *this,
 	return skt;
 }
 
+METHOD(socket_t, get_port, u_int16_t,
+	private_socket_raw_socket_t *this, bool nat_t)
+{
+	return nat_t ? CHARON_NATT_PORT : CHARON_UDP_PORT;
+}
+
 /**
  * open a socket to receive packets
  */
@@ -616,6 +622,7 @@ socket_raw_socket_t *socket_raw_socket_create()
 			.socket = {
 				.send = _sender,
 				.receive = _receiver,
+				.get_port = _get_port,
 				.destroy = _destroy,
 			},
 		},