6 Dec
2013
6 Dec
'13
2:39 p.m.
This patch parses the MGCP 'p' value of the local connection options,
the 'ptime' and 'maxptime' SDP attributes, and the SDP rate
information and sets up packet_duration_ms accordingly. The MGCP 'p' has
priority over the values derived from the SDP data. If the packet
duration is unknown or allows for different values (e.g. because 'p'
uses a range or maxptime allows for more than one frame) the duration
is set to 0.
Sponsored-by: On-Waves ehf
---
openbsc/src/libmgcp/mgcp_network.c | 9 ++++
openbsc/src/libmgcp/mgcp_protocol.c | 89 +++++++++++++++++++++++++++++++----
openbsc/tests/mgcp/mgcp_test.c | 4 ++
openbsc/tests/mgcp/mgcp_test.ok | 14 +++---
4 files changed, 100 insertions(+), 16 deletions(-)
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 8bd8afb..40227af 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -300,6 +300,15 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct
mgcp_rtp_state *sta
state->seq_offset, state->packet_duration,
inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
endp->conn_mode);
+ if (state->packet_duration == 0 && rtp_end->force_constant_timing)
+ LOGP(DMGCP, LOGL_ERROR,
+ "Cannot patch timestamps on 0x%x: "
+ "RTP packet duration is unknown, SSRC: %u, "
+ "from %s:%d in %d\n",
+ ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
+ inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+ endp->conn_mode);
+
} else if (state->in_stream.ssrc != ssrc) {
LOGP(DMGCP, LOGL_NOTICE,
"The SSRC changed on 0x%x: %u -> %u "
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index 3e26ad6..ba53df1 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -75,7 +75,7 @@ char *strline_r(char *str, char **saveptr)
/* Assume audio frame length of 20ms */
#define DEFAULT_RTP_AUDIO_FRAME_DUR_NUM 20
#define DEFAULT_RTP_AUDIO_FRAME_DUR_DEN 1000
-#define DEFAULT_RTP_AUDIO_PACKET_DURATION_MS 20
+#define DEFAULT_RTP_AUDIO_PACKET_DURATION_MS 0 /* we don't know */
#define DEFAULT_RTP_AUDIO_DEFAULT_RATE 8000
static void mgcp_rtp_end_reset(struct mgcp_rtp_end *end);
@@ -562,25 +562,64 @@ static int parse_sdp_data(struct mgcp_rtp_end *rtp, struct
mgcp_parse_data *p)
{
char *line;
int found_media = 0;
+ int audio_payload = -1;
for_each_line(line, p->save) {
switch (line[0]) {
- case 'a':
case 'o':
case 's':
case 't':
case 'v':
/* skip these SDP attributes */
break;
+ case 'a': {
+ int payload;
+ int rate;
+ int channels = 1;
+ int ptime, ptime2 = 0;
+ char audio_name[64];
+ char audio_codec[64];
+
+ if (audio_payload == -1)
+ break;
+
+ if (sscanf(line, "a=rtpmap:%d %64s",
+ &payload, audio_name) == 2) {
+ if (payload != audio_payload)
+ break;
+
+ if (sscanf(audio_name, "%[^/]/%d/%d",
+ audio_codec, &rate, &channels) < 2)
+ break;
+
+ rtp->rate = rate;
+ if (channels != 1)
+ LOGP(DMGCP, LOGL_NOTICE,
+ "Channels != 1 in SDP: '%s' on 0x%x\n",
+ line, ENDPOINT_NUMBER(p->endp));
+ } else if (sscanf(line, "a=ptime:%d-%d",
+ &ptime, &ptime2) >= 1) {
+ if (ptime2 > 0 && ptime2 != ptime)
+ rtp->packet_duration_ms = 0;
+ else
+ rtp->packet_duration_ms = ptime;
+ } else if (sscanf(line, "a=maxptime:%d", &ptime2) == 1) {
+ if (ptime2 * rtp->frame_duration_den >
+ rtp->frame_duration_num * 1500)
+ /* more than 1 frame */
+ rtp->packet_duration_ms = 0;
+ }
+ break;
+ }
case 'm': {
int port;
- int payload;
+ audio_payload = -1;
if (sscanf(line, "m=audio %d RTP/AVP %d",
- &port, &payload) == 2) {
+ &port, &audio_payload) == 2) {
rtp->rtp_port = htons(port);
rtp->rtcp_port = htons(port + 1);
- rtp->payload_type = payload;
+ rtp->payload_type = audio_payload;
found_media = 1;
}
break;
@@ -608,12 +647,33 @@ static int parse_sdp_data(struct mgcp_rtp_end *rtp, struct
mgcp_parse_data *p)
if (found_media)
LOGP(DMGCP, LOGL_NOTICE,
- "Got media info via SDP: port %d, payload %d, addr %s\n",
- ntohs(rtp->rtp_port), rtp->payload_type, inet_ntoa(rtp->addr));
+ "Got media info via SDP: port %d, payload %d, "
+ "duration %d, addr %s\n",
+ ntohs(rtp->rtp_port), rtp->payload_type,
+ rtp->packet_duration_ms, inet_ntoa(rtp->addr));
return found_media;
}
+static void parse_local_cx_options(struct mgcp_rtp_end *rtp, const char *options)
+{
+ int ptime, ptime2 = 0;
+ char *p_opt = strstr(options, "p:");
+ if (p_opt && sscanf(p_opt, "p:%d-%d", &ptime, &ptime2) >=
1) {
+ if (ptime2 > 0 && ptime2 != ptime)
+ ptime = 0;
+
+ if (rtp->packet_duration_ms &&
+ rtp->packet_duration_ms != ptime)
+ LOGP(DMGCP, LOGL_NOTICE,
+ "CRCX inconsistent ptime: SDP: %d, L: %d "
+ "(will use %d)\n",
+ rtp->packet_duration_ms, ptime, ptime);
+
+ rtp->packet_duration_ms = ptime;
+ }
+}
+
void mgcp_rtp_end_config(struct mgcp_endpoint *endp, int expect_ssrc_change,
struct mgcp_rtp_end *rtp)
{
@@ -707,7 +767,8 @@ mgcp_header_done:
endp->callid = talloc_strdup(tcfg->endpoints, callid);
if (local_options)
- endp->local_options = talloc_strdup(tcfg->endpoints, local_options);
+ endp->local_options = talloc_strdup(tcfg->endpoints,
+ local_options);
if (parse_conn_mode(mode, &endp->conn_mode) != 0) {
error_code = 517;
@@ -740,6 +801,9 @@ mgcp_header_done:
if (have_sdp)
parse_sdp_data(&endp->net_end, p);
+ if (local_options)
+ parse_local_cx_options(&endp->net_end, local_options);
+
/* policy CB */
if (p->cfg->policy_cb) {
int rc;
@@ -783,6 +847,7 @@ static struct msgb *handle_modify_con(struct mgcp_parse_data *p)
int error_code = 500;
int silent = 0;
char *line;
+ const char *local_options = NULL;
if (p->found != 0)
return create_err_response(NULL, 510, "MDCX", p->trans);
@@ -806,7 +871,7 @@ static struct msgb *handle_modify_con(struct mgcp_parse_data *p)
break;
}
case 'L':
- /* skip */
+ local_options = (const char *) line + 3;
break;
case 'M':
if (parse_conn_mode(line + 3, &endp->conn_mode) != 0) {
@@ -832,6 +897,12 @@ static struct msgb *handle_modify_con(struct mgcp_parse_data *p)
}
}
+ if (local_options) {
+ endp->local_options = talloc_strdup(endp->tcfg->endpoints,
+ local_options);
+ parse_local_cx_options(&endp->net_end, local_options);
+ }
+
/* policy CB */
if (p->cfg->policy_cb) {
int rc;
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index 11e4b56..fb056e6 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -628,6 +628,10 @@ static void test_packet_error_detection(int patch_ssrc, int
patch_ts)
* trunk.endpoints are set up properly. */
mgcp_free_endp(&endp);
+ /* There is no MGCP/SDP around, so set this by hand to make timestamp
+ * patching possible */
+ rtp->packet_duration_ms = 20;
+
rtp->payload_type = 98;
for (i = 0; i < ARRAY_SIZE(test_rtp_packets1); ++i) {
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index 5c6fe37..32af3b5 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -16,19 +16,19 @@ Testing AUEP2
Testing MDCX1
Testing MDCX2
Testing CRCX
-Packet duration not set
+Detected packet duration: 20
Testing MDCX3
Packet duration not set
Testing MDCX4
-Packet duration not set
+Detected packet duration: 20
Testing MDCX4_PT1
-Packet duration not set
+Detected packet duration: 0
Testing MDCX4_PT2
-Packet duration not set
+Detected packet duration: 20
Testing MDCX4_PT3
-Packet duration not set
+Detected packet duration: 40
Testing DLCX
-Detected packet duration: 20
+Detected packet duration: 0
Testing CRCX_ZYN
Packet duration not set
Testing EMPTY
@@ -39,7 +39,7 @@ Testing SHORT4
Testing RQNT1
Testing RQNT2
Testing DLCX
-Detected packet duration: 20
+Detected packet duration: 0
Testing CRCX
Re-transmitting CRCX
Testing RQNT1
--
1.7.9.5