[PATCH 4/6] mgcp/rtp: Cleanup usage of variables in mgcp_patch_and_count()

The ssrc has been used without respect to proper byte ordering. The timestap_offset and seq_offset variables has been set even when patching was not allowed. This patch introduces a new variable 'ssrc' that takes the value of the SSRC in proper byte order. The offsets in the state are only updated if SSRC patching is allowed. Sponsored-by: On-Waves ehf --- openbsc/include/openbsc/mgcp_internal.h | 1 + openbsc/src/libmgcp/mgcp_network.c | 73 ++++++++++++++++++++----------- openbsc/src/libmgcp/mgcp_protocol.c | 3 ++ 3 files changed, 52 insertions(+), 25 deletions(-) diff --git a/openbsc/include/openbsc/mgcp_internal.h b/openbsc/include/openbsc/mgcp_internal.h index 02e193d..b16bd49 100644 --- a/openbsc/include/openbsc/mgcp_internal.h +++ b/openbsc/include/openbsc/mgcp_internal.h @@ -59,6 +59,7 @@ struct mgcp_rtp_state { int cycles; int32_t timestamp_offset; + uint32_t packet_duration; uint32_t jitter; int32_t transit; diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c index ce4e1d3..137ddba 100644 --- a/openbsc/src/libmgcp/mgcp_network.c +++ b/openbsc/src/libmgcp/mgcp_network.c @@ -216,7 +216,7 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta uint32_t arrival_time; int32_t transit, d; uint16_t seq, udelta; - uint32_t timestamp; + uint32_t timestamp, ssrc; struct rtp_hdr *rtp_hdr; int payload = rtp_end->payload_type; @@ -227,31 +227,43 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta seq = ntohs(rtp_hdr->sequence); timestamp = ntohl(rtp_hdr->timestamp); arrival_time = get_current_ts(); + ssrc = ntohl(rtp_hdr->ssrc); if (!state->initialized) { state->in_stream.last_seq = seq - 1; - state->in_stream.ssrc = state->orig_ssrc = rtp_hdr->ssrc; + state->in_stream.ssrc = state->orig_ssrc = ssrc; state->in_stream.last_tsdelta = 0; state->base_seq = seq; state->initialized = 1; state->jitter = 0; state->transit = arrival_time - timestamp; + state->packet_duration = + rtp_end->rate * rtp_end->frames_per_packet * + rtp_end->frame_duration_num / + rtp_end->frame_duration_den; state->out_stream = state->in_stream; state->out_stream.last_timestamp = timestamp; - state->out_stream.ssrc = rtp_hdr->ssrc - 1; /* SSRC change <=> initialisation */ + state->out_stream.ssrc = ssrc - 1; /* SSRC change <=> initialisation */ LOGP(DMGCP, LOGL_INFO, "Initializing stream on 0x%x SSRC: %u timestamp: %u " + "pkt-duration: %d, from %s:%d in %d\n", + ENDPOINT_NUMBER(endp), state->in_stream.ssrc, + state->seq_offset, state->packet_duration, + inet_ntoa(addr->sin_addr), ntohs(addr->sin_port), + endp->conn_mode); + } else if (state->in_stream.ssrc != ssrc) { + int32_t tsdelta; + + LOGP(DMGCP, LOGL_NOTICE, + "The SSRC changed on 0x%x SSRC: %u " "from %s:%d in %d\n", ENDPOINT_NUMBER(endp), state->in_stream.ssrc, - state->seq_offset, inet_ntoa(addr->sin_addr), ntohs(addr->sin_port), endp->conn_mode); - } else if (state->in_stream.ssrc != rtp_hdr->ssrc) { - int32_t tsdelta = state->out_stream.last_tsdelta; + + tsdelta = state->out_stream.last_tsdelta; if (tsdelta == 0) { - tsdelta = rtp_end->rate * rtp_end->frames_per_packet * - rtp_end->frame_duration_num / - rtp_end->frame_duration_den; + tsdelta = state->packet_duration; LOGP(DMGCP, LOGL_NOTICE, "Computed timestamp delta %d based on " "rate %d, num frames %d, frame duration %d/%d\n", @@ -259,18 +271,25 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta rtp_end->frame_duration_num, rtp_end->frame_duration_den); } - state->in_stream.ssrc = rtp_hdr->ssrc; - state->seq_offset = (state->out_stream.last_seq + 1) - seq; - state->timestamp_offset = - (state->out_stream.last_timestamp + tsdelta) - timestamp; - state->patch = rtp_end->force_constant_ssrc; - LOGP(DMGCP, LOGL_NOTICE, - "The SSRC changed on 0x%x SSRC: %u offset: %d tsdelta: %d " - "from %s:%d in %d\n", - ENDPOINT_NUMBER(endp), state->in_stream.ssrc, - state->seq_offset, tsdelta, - inet_ntoa(addr->sin_addr), ntohs(addr->sin_port), - endp->conn_mode); + state->in_stream.ssrc = ssrc; + if (rtp_end->force_constant_ssrc) { + state->seq_offset = + (state->out_stream.last_seq + 1) - seq; + state->timestamp_offset = + (state->out_stream.last_timestamp + tsdelta) - + timestamp; + state->patch = 1; + ssrc = state->orig_ssrc; + + LOGP(DMGCP, LOGL_NOTICE, + "SSRC patching enabled on 0x%x SSRC: %u " + "offset: %d tsdelta: %d " + "from %s:%d in %d\n", + ENDPOINT_NUMBER(endp), state->in_stream.ssrc, + state->seq_offset, tsdelta, + inet_ntoa(addr->sin_addr), ntohs(addr->sin_port), + endp->conn_mode); + } state->in_stream.last_tsdelta = 0; } else { @@ -278,6 +297,9 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta check_rtp_timestamp(endp, &state->in_stream, rtp_end, addr, seq, timestamp, "input", &state->in_stream.last_tsdelta); + + if (state->patch) + ssrc = state->orig_ssrc; } /* Save before patching */ @@ -288,14 +310,15 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta if (state->patch) { seq += state->seq_offset; rtp_hdr->sequence = htons(seq); - rtp_hdr->ssrc = state->orig_ssrc; + rtp_hdr->ssrc = htonl(ssrc); timestamp += state->timestamp_offset; rtp_hdr->timestamp = htonl(timestamp); - } + } else + ssrc = ntohl(rtp_hdr->ssrc); /* Check again, whether the timestamps are still valid */ - if (state->out_stream.ssrc == rtp_hdr->ssrc) + if (state->out_stream.ssrc == ssrc) check_rtp_timestamp(endp, &state->out_stream, rtp_end, addr, seq, timestamp, "output", &state->out_stream.last_tsdelta); @@ -332,7 +355,7 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta /* Save output values */ state->out_stream.last_seq = seq; state->out_stream.last_timestamp = timestamp; - state->out_stream.ssrc = rtp_hdr->ssrc; + state->out_stream.ssrc = ssrc; if (payload < 0) return; diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c index 6d31ace..8693396 100644 --- a/openbsc/src/libmgcp/mgcp_protocol.c +++ b/openbsc/src/libmgcp/mgcp_protocol.c @@ -834,6 +834,9 @@ static struct msgb *handle_modify_con(struct mgcp_parse_data *p) } } + mgcp_rtp_end_config(endp, 1, &endp->net_end); + mgcp_rtp_end_config(endp, 1, &endp->bts_end); + /* modify */ LOGP(DMGCP, LOGL_DEBUG, "Modified endpoint on: 0x%x Server: %s:%u\n", ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr), ntohs(endp->net_end.rtp_port)); -- 1.7.9.5