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Jacob Erlbeck jerlbeck at sysmocom.deThis forces the output timing to fulfill
dTS = dSegNo * fixedPacketDuration
where dSegNo = seqNo - lastSeqNo.
If timestamp patching is enabled, the output timestamp will be set
to lastTimestamp + dTS. This kind of relative updating is used to
handle seqNo- and timestamp-wraparounds properly.
The updating of timestamp and SSRC has been separated and the patch
field of mgcp_rtp_state has been renamed to patch_ssrc to reflect
it's semantics more closely. The offset fields are now used always
and will change the corresponding header field if they are != 0.
Ticket: OW#1065
Sponsored-by: On-Waves ehf
---
openbsc/include/openbsc/mgcp_internal.h | 2 +-
openbsc/src/libmgcp/mgcp_network.c | 40 +++++++++++++----
openbsc/tests/mgcp/mgcp_test.ok | 72 +++++++++++++++----------------
3 files changed, 68 insertions(+), 46 deletions(-)
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h
index 255161f..b6f4a0d 100644
--- a/openbsc/include/openbsc/mgcp_internal.h
+++ b/openbsc/include/openbsc/mgcp_internal.h
@@ -50,7 +50,7 @@ struct mgcp_rtp_stream_state {
struct mgcp_rtp_state {
int initialized;
- int patch;
+ int patch_ssrc;
uint32_t orig_ssrc;
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 79c9e1a..6463ae0 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -278,7 +278,7 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
state->timestamp_offset =
(state->out_stream.last_timestamp + tsdelta) -
timestamp;
- state->patch = 1;
+ state->patch_ssrc = 1;
ssrc = state->orig_ssrc;
if (rtp_end->force_constant_ssrc != -1)
rtp_end->force_constant_ssrc -= 1;
@@ -300,7 +300,7 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
seq, timestamp, "input",
&state->in_stream.last_tsdelta);
- if (state->patch)
+ if (state->patch_ssrc)
ssrc = state->orig_ssrc;
}
@@ -308,16 +308,38 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
state->in_stream.last_timestamp = timestamp;
state->in_stream.last_seq = seq;
- /* apply the offset and store it back to the packet */
- if (state->patch) {
- seq += state->seq_offset;
- rtp_hdr->sequence = htons(seq);
- rtp_hdr->ssrc = htonl(ssrc);
+ if (rtp_end->force_constant_timing &&
+ state->out_stream.ssrc == ssrc && state->packet_duration) {
+ int delta_seq = seq + state->seq_offset - state->out_stream.last_seq;
+ int timestamp_offset =
+ state->out_stream.last_timestamp - timestamp +
+ delta_seq * state->packet_duration;
+ if (state->timestamp_offset != timestamp_offset) {
+ state->timestamp_offset = timestamp_offset;
- timestamp += state->timestamp_offset;
- rtp_hdr->timestamp = htonl(timestamp);
+ LOGP(DMGCP, LOGL_NOTICE,
+ "Timestamp patching enabled on 0x%x SSRC: %u "
+ "SeqNo delta: %d, TS offset: %d, "
+ "from %s:%d in %d\n",
+ ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
+ delta_seq, state->timestamp_offset,
+ inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+ endp->conn_mode);
+ }
}
+ /* Store the updated SSRC back to the packet */
+ if (state->patch_ssrc)
+ rtp_hdr->ssrc = htonl(ssrc);
+
+ /* Apply the offset and store it back to the packet.
+ * This won't change anything if the offset is 0, so the conditional is
+ * omitted. */
+ seq += state->seq_offset;
+ rtp_hdr->sequence = htons(seq);
+ timestamp += state->timestamp_offset;
+ rtp_hdr->timestamp = htonl(timestamp);
+
/* Check again, whether the timestamps are still valid */
if (state->out_stream.ssrc == ssrc)
check_rtp_timestamp(endp, &state->out_stream, rtp_end, addr,
diff --git a/openbsc/tests/mgcp/mgcp_test.ok b/openbsc/tests/mgcp/mgcp_test.ok
index 4d3caac..3beeb59 100644
--- a/openbsc/tests/mgcp/mgcp_test.ok
+++ b/openbsc/tests/mgcp/mgcp_test.ok
@@ -94,46 +94,46 @@ Output SSRC changed to 11223344
TS: 0, dTS: 0, TS Errs: in 0, out 0
TS: 160, dTS: 160, TS Errs: in 0, out 0
TS: 320, dTS: 160, TS Errs: in 0, out 0
-TS: 320, dTS: 160, TS Errs: in 1, out 1
-TS: 480, dTS: 160, TS Errs: in 1, out 1
-TS: 640, dTS: 160, TS Errs: in 1, out 1
-TS: 960, dTS: 320, TS Errs: in 2, out 2
-TS: 1120, dTS: 160, TS Errs: in 3, out 3
-TS: 1280, dTS: 160, TS Errs: in 3, out 3
-TS: 1400, dTS: 120, TS Errs: in 4, out 4
-TS: 1560, dTS: 160, TS Errs: in 5, out 5
-TS: 1720, dTS: 160, TS Errs: in 5, out 5
+TS: 480, dTS: 160, TS Errs: in 1, out 0
+TS: 640, dTS: 160, TS Errs: in 1, out 0
+TS: 800, dTS: 160, TS Errs: in 1, out 0
+TS: 960, dTS: 160, TS Errs: in 2, out 0
+TS: 1120, dTS: 160, TS Errs: in 3, out 0
+TS: 1280, dTS: 160, TS Errs: in 3, out 0
+TS: 1440, dTS: 160, TS Errs: in 4, out 0
+TS: 1600, dTS: 160, TS Errs: in 5, out 0
+TS: 1760, dTS: 160, TS Errs: in 5, out 0
Output SSRC changed to 10203040
-TS: 34688, dTS: 160, TS Errs: in 5, out 5
-TS: 34848, dTS: 160, TS Errs: in 5, out 5
-TS: 35008, dTS: 160, TS Errs: in 5, out 5
-TS: 35128, dTS: 120, TS Errs: in 6, out 6
-TS: 35288, dTS: 160, TS Errs: in 7, out 7
-TS: 35448, dTS: 160, TS Errs: in 7, out 7
-TS: 35768, dTS: 160, TS Errs: in 7, out 7
-TS: 35928, dTS: 160, TS Errs: in 7, out 7
-TS: 36088, dTS: 160, TS Errs: in 8, out 8
+TS: 34728, dTS: 160, TS Errs: in 5, out 0
+TS: 34888, dTS: 160, TS Errs: in 5, out 0
+TS: 35048, dTS: 160, TS Errs: in 5, out 0
+TS: 35208, dTS: 160, TS Errs: in 6, out 0
+TS: 35368, dTS: 160, TS Errs: in 7, out 0
+TS: 35528, dTS: 160, TS Errs: in 7, out 0
+TS: 35848, dTS: 160, TS Errs: in 7, out 0
+TS: 36008, dTS: 160, TS Errs: in 7, out 0
+TS: 36008, dTS: 160, TS Errs: in 8, out 0
Testing packet error detection, patch SSRC, patch timestamps.
Output SSRC changed to 11223344
TS: 0, dTS: 0, TS Errs: in 0, out 0
TS: 160, dTS: 160, TS Errs: in 0, out 0
TS: 320, dTS: 160, TS Errs: in 0, out 0
-TS: 320, dTS: 160, TS Errs: in 1, out 1
-TS: 480, dTS: 160, TS Errs: in 1, out 1
-TS: 640, dTS: 160, TS Errs: in 1, out 1
-TS: 960, dTS: 320, TS Errs: in 2, out 2
-TS: 1120, dTS: 160, TS Errs: in 3, out 3
-TS: 1280, dTS: 160, TS Errs: in 3, out 3
-TS: 1400, dTS: 120, TS Errs: in 4, out 4
-TS: 1560, dTS: 160, TS Errs: in 5, out 5
-TS: 1720, dTS: 160, TS Errs: in 5, out 5
-TS: 1880, dTS: 160, TS Errs: in 5, out 5
-TS: 2040, dTS: 160, TS Errs: in 5, out 5
-TS: 2200, dTS: 160, TS Errs: in 5, out 5
-TS: 2320, dTS: 120, TS Errs: in 6, out 6
-TS: 2480, dTS: 160, TS Errs: in 7, out 7
-TS: 2640, dTS: 160, TS Errs: in 7, out 7
-TS: 2960, dTS: 160, TS Errs: in 7, out 7
-TS: 3120, dTS: 160, TS Errs: in 7, out 7
-TS: 3280, dTS: 160, TS Errs: in 8, out 8
+TS: 480, dTS: 160, TS Errs: in 1, out 0
+TS: 640, dTS: 160, TS Errs: in 1, out 0
+TS: 800, dTS: 160, TS Errs: in 1, out 0
+TS: 960, dTS: 160, TS Errs: in 2, out 0
+TS: 1120, dTS: 160, TS Errs: in 3, out 0
+TS: 1280, dTS: 160, TS Errs: in 3, out 0
+TS: 1440, dTS: 160, TS Errs: in 4, out 0
+TS: 1600, dTS: 160, TS Errs: in 5, out 0
+TS: 1760, dTS: 160, TS Errs: in 5, out 0
+TS: 1920, dTS: 160, TS Errs: in 5, out 0
+TS: 2080, dTS: 160, TS Errs: in 5, out 0
+TS: 2240, dTS: 160, TS Errs: in 5, out 0
+TS: 2400, dTS: 160, TS Errs: in 6, out 0
+TS: 2560, dTS: 160, TS Errs: in 7, out 0
+TS: 2720, dTS: 160, TS Errs: in 7, out 0
+TS: 3040, dTS: 160, TS Errs: in 7, out 0
+TS: 3200, dTS: 160, TS Errs: in 7, out 0
+TS: 3200, dTS: 160, TS Errs: in 8, out 0
Done
--
1.7.9.5