diff options
Diffstat (limited to 'openbsc')
| -rw-r--r-- | openbsc/include/openbsc/mgcp_internal.h | 5 | ||||
| -rw-r--r-- | openbsc/src/mgcp/mgcp_network.c | 28 |
2 files changed, 30 insertions, 3 deletions
diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h index adb01f467..f6f8d6ebb 100644 --- a/openbsc/include/openbsc/mgcp_internal.h +++ b/openbsc/include/openbsc/mgcp_internal.h @@ -39,8 +39,13 @@ enum mgcp_connection_mode { struct mgcp_rtp_state { int initialized; + uint32_t orig_ssrc; + uint32_t ssrc; uint16_t seq_no; int lost_no; + int seq_offset; + uint32_t last_timestamp; + int32_t timestamp_offset; }; struct mgcp_endpoint { diff --git a/openbsc/src/mgcp/mgcp_network.c b/openbsc/src/mgcp/mgcp_network.c index d2dbeebe4..b5e2cddf8 100644 --- a/openbsc/src/mgcp/mgcp_network.c +++ b/openbsc/src/mgcp/mgcp_network.c @@ -97,6 +97,7 @@ int mgcp_send_dummy(struct mgcp_endpoint *endp) static void patch_and_count(struct mgcp_rtp_state *state, int payload, char *data, int len) { uint16_t seq; + uint32_t timestamp; struct rtp_hdr *rtp_hdr; if (len < sizeof(*rtp_hdr)) @@ -104,15 +105,36 @@ static void patch_and_count(struct mgcp_rtp_state *state, int payload, char *dat rtp_hdr = (struct rtp_hdr *) data; seq = ntohs(rtp_hdr->sequence); + timestamp = ntohl(rtp_hdr->timestamp); if (!state->initialized) { - state->seq_no = seq; + state->seq_no = seq - 1; + state->ssrc = state->orig_ssrc = rtp_hdr->ssrc; state->initialized = 1; - } else if (state->seq_no + 1u != seq) - state->lost_no = abs(seq - (state->seq_no + 1)); + state->last_timestamp = timestamp; + } else if (state->ssrc != rtp_hdr->ssrc) { + state->ssrc = rtp_hdr->ssrc; + state->seq_offset = (state->seq_no + 1) - seq; + state->timestamp_offset = state->last_timestamp - timestamp; + LOGP(DMGCP, LOGL_NOTICE, "The SSRC changed... SSRC: %u offset: %d\n", + state->ssrc, state->seq_offset); + } + + /* apply the offset and store it back to the packet */ + seq += state->seq_offset; + rtp_hdr->sequence = htons(seq); + rtp_hdr->ssrc = state->orig_ssrc; + timestamp += state->timestamp_offset; + rtp_hdr->timestamp = htonl(timestamp); + + /* seq changed, now compare if we have lost something */ + if (state->seq_no + 1u != seq) + state->lost_no = abs(seq - (state->seq_no + 1)); state->seq_no = seq; + state->last_timestamp = timestamp; + if (payload < 0) return; |