mgcp: Add a call tap feature to forward audio to another forward port

For debugging it is useful to forward (tee) UDP packets to another
system and use gstreamer to inspect the rtp stream. This is untested
code and might contain bugs.... and of course only tap your own calls.

1 files changed, 15 insertions, 0 deletions

diff --git a/openbsc/src/mgcp/mgcp_network.c b/openbsc/src/mgcp/mgcp_network.c
index 387711298..bbc46f418 100644
--- a/openbsc/src/mgcp/mgcp_network.c
+++ b/openbsc/src/mgcp/mgcp_network.c
@@ -151,6 +151,14 @@ static void patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *s
  * The below code is for dispatching. We have a dedicated port for
  * the data coming from the net and one to discover the BTS.
  */
+static int forward_data(int fd, struct mgcp_rtp_tap *tap, const char *buf, int len)
+{
+	if (!tap->enabled)
+		return 0;
+
+	return sendto(fd, buf, len, 0,
+		      (struct sockaddr *)&tap->forward, sizeof(tap->forward));
+}
 static int send_to(struct mgcp_endpoint *endp, int dest, int is_rtp,
 		   struct sockaddr_in *addr, char *buf, int rc)
 {
@@ -168,6 +176,8 @@ static int send_to(struct mgcp_endpoint *endp, int dest, int is_rtp,
 			patch_and_count(endp, &endp->bts_state,
 					endp->net_end.payload_type,
 					addr, buf, rc);
+			forward_data(endp->net_end.rtp.fd,
+				     &endp->taps[MGCP_TAP_NET_OUT], buf, rc);
 			return udp_send(endp->net_end.rtp.fd, &endp->net_end.addr,
 					endp->net_end.rtp_port, buf, rc);
 		} else {
@@ -179,6 +189,8 @@ static int send_to(struct mgcp_endpoint *endp, int dest, int is_rtp,
 			patch_and_count(endp, &endp->net_state,
 					endp->bts_end.payload_type,
 					addr, buf, rc);
+			forward_data(endp->bts_end.rtp.fd,
+				     &endp->taps[MGCP_TAP_BTS_OUT], buf, rc);
 			return udp_send(endp->bts_end.rtp.fd, &endp->bts_end.addr,
 					endp->bts_end.rtp_port, buf, rc);
 		} else {
@@ -248,6 +260,8 @@ static int rtp_data_net(struct bsc_fd *fd, unsigned int what)
 
 	proto = fd == &endp->net_end.rtp ? PROTO_RTP : PROTO_RTCP;
 	endp->net_end.packets += 1;
+
+	forward_data(fd->fd, &endp->taps[MGCP_TAP_NET_IN], buf, rc);
 	return send_to(endp, DEST_BTS, proto == PROTO_RTP, &addr, &buf[0], rc);
 }
 
@@ -310,6 +324,7 @@ static int rtp_data_bts(struct bsc_fd *fd, unsigned int what)
 	/* do this before the loop handling */
 	endp->bts_end.packets += 1;
 
+	forward_data(fd->fd, &endp->taps[MGCP_TAP_BTS_IN], buf, rc);
 	return send_to(endp, DEST_NETWORK, proto == PROTO_RTP, &addr, &buf[0], rc);
 }