mgcp/rtp: Send dummy packet to the RTCP destination, too

Currently a dummy packet is only sent to the RTP port. This is not
enough if RTCP must also cross the SNAT.

This patch sends an additional dummy packet to the RTCP net
destination if omit_rtcp is not set.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 04e6cbe..0cc2041 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -129,9 +129,16 @@
 int mgcp_send_dummy(struct mgcp_endpoint *endp)
 {
 	static char buf[] = { MGCP_DUMMY_LOAD };
+	int rc;
 
-	return mgcp_udp_send(endp->net_end.rtp.fd, &endp->net_end.addr,
-			     endp->net_end.rtp_port, buf, 1);
+	rc = mgcp_udp_send(endp->net_end.rtp.fd, &endp->net_end.addr,
+			   endp->net_end.rtp_port, buf, 1);
+
+	if (rc == -1 || endp->tcfg->omit_rtcp)
+		return rc;
+
+	return mgcp_udp_send(endp->net_end.rtcp.fd, &endp->net_end.addr,
+			     endp->net_end.rtcp_port, buf, 1);
 }
 
 static int32_t compute_timestamp_aligment_error(struct mgcp_rtp_stream_state *sstate,