mavlink: keep trying to find to broadcast

This should help the Snapdragon to connect if the network is not yet up
by the time the mainapp starts. It will retry to find a network and
broadcast once it finds one.

src/modules/mavlink/mavlink_main.cpp

@@ -885,13 +885,20 @@ Mavlink::send_message(const uint8_t msgid, const void *msg, uint8_t component_ID
 		if ((_mode != MAVLINK_MODE_ONBOARD) &&
 			(!get_client_source_initialized()
 			|| (hrt_elapsed_time(&tstatus.heartbeat_time) > 3 * 1000 * 1000))
-			&& (msgid == MAVLINK_MSG_ID_HEARTBEAT)
-			&& _broadcast_address_found) {
+			&& (msgid == MAVLINK_MSG_ID_HEARTBEAT)) {
 
-			int bret = sendto(_socket_fd, buf, packet_len, 0, (struct sockaddr *)&_bcast_addr, sizeof(_bcast_addr));
+			if (!_broadcast_address_found) {
+				// Try to initialize UDP and broadcast address again.
+				init_udp();
+			}
+
+			if (_broadcast_address_found) {
 
-			if (bret <= 0) {
-				PX4_WARN("sending broadcast failed, errno: %d: %s", errno, strerror(errno));
+				int bret = sendto(_socket_fd, buf, packet_len, 0, (struct sockaddr *)&_bcast_addr, sizeof(_bcast_addr));
+
+				if (bret <= 0) {
+					PX4_WARN("sending broadcast failed, errno: %d: %s", errno, strerror(errno));
+				}
 			}
 		}