mgcp: Introduce trans_bts and send BTS packets from this port

Introduce the trans_bts. Right now only a port is allocated
and the packets from the BTS are sent from this socket.
diff --git a/openbsc/src/mgcp/mgcp_network.c b/openbsc/src/mgcp/mgcp_network.c
index f78e42a..ae0504f 100644
--- a/openbsc/src/mgcp/mgcp_network.c
+++ b/openbsc/src/mgcp/mgcp_network.c
@@ -191,8 +191,8 @@
 	addr.sin_port = htons(port);
 
 	rc = sendto(is_rtp ?
-		endp->bts_end.rtp.fd :
-		endp->bts_end.rtcp.fd, buf, len, 0,
+		endp->trans_bts.rtp.fd :
+		endp->trans_bts.rtcp.fd, buf, len, 0,
 		(struct sockaddr *) &addr, sizeof(addr));
 
 	if (rc != len)
@@ -543,7 +543,7 @@
 	return bind_rtp(endp->cfg, &endp->net_end, ENDPOINT_NUMBER(endp));
 }
 
-int mgcp_bind_transcoder_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
+int mgcp_bind_trans_net_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
 {
 	if (endp->trans_net.rtp.fd != -1 || endp->trans_net.rtcp.fd != -1) {
 		LOGP(DMGCP, LOGL_ERROR, "Previous net-port was still bound on %d\n",
@@ -559,6 +559,22 @@
 	return bind_rtp(endp->cfg, &endp->trans_net, ENDPOINT_NUMBER(endp));
 }
 
+int mgcp_bind_trans_bts_rtp_port(struct mgcp_endpoint *endp, int rtp_port)
+{
+	if (endp->trans_bts.rtp.fd != -1 || endp->trans_bts.rtcp.fd != -1) {
+		LOGP(DMGCP, LOGL_ERROR, "Previous net-port was still bound on %d\n",
+			ENDPOINT_NUMBER(endp));
+		mgcp_free_rtp_port(&endp->trans_bts);
+	}
+
+	endp->trans_bts.local_port = rtp_port;
+	endp->trans_bts.rtp.cb = rtp_data_transcoder;
+	endp->trans_bts.rtp.data = endp;
+	endp->trans_bts.rtcp.data = endp;
+	endp->trans_bts.rtcp.cb = rtp_data_transcoder;
+	return bind_rtp(endp->cfg, &endp->trans_bts, ENDPOINT_NUMBER(endp));
+}
+
 int mgcp_free_rtp_port(struct mgcp_rtp_end *end)
 {
 	if (end->rtp.fd != -1) {