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/*
* Some SDP file parsing...
*
* (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2009-2014 by On-Waves
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <openbsc/mgcp.h>
#include <openbsc/mgcp_internal.h>
#include <errno.h>
struct sdp_rtp_map {
/* the type */
int payload_type;
/* null, static or later dynamic codec name */
char *codec_name;
/* A pointer to the original line for later parsing */
char *map_line;
int rate;
int channels;
};
int mgcp_set_audio_info(void *ctx, struct mgcp_rtp_codec *codec,
int payload_type, const char *audio_name)
{
int rate = codec->rate;
int channels = codec->channels;
char audio_codec[64];
talloc_free(codec->subtype_name);
codec->subtype_name = NULL;
talloc_free(codec->audio_name);
codec->audio_name = NULL;
if (payload_type != PTYPE_UNDEFINED)
codec->payload_type = payload_type;
if (!audio_name) {
switch (payload_type) {
case 0: audio_name = "PCMU/8000/1"; break;
case 3: audio_name = "GSM/8000/1"; break;
case 8: audio_name = "PCMA/8000/1"; break;
case 18: audio_name = "G729/8000/1"; break;
default:
/* Payload type is unknown, don't change rate and
* channels. */
/* TODO: return value? */
return 0;
}
}
if (sscanf(audio_name, "%63[^/]/%d/%d",
audio_codec, &rate, &channels) < 1)
return -EINVAL;
codec->rate = rate;
codec->channels = channels;
codec->subtype_name = talloc_strdup(ctx, audio_codec);
codec->audio_name = talloc_strdup(ctx, audio_name);
if (!strcmp(audio_codec, "G729")) {
codec->frame_duration_num = 10;
codec->frame_duration_den = 1000;
} else {
codec->frame_duration_num = DEFAULT_RTP_AUDIO_FRAME_DUR_NUM;
codec->frame_duration_den = DEFAULT_RTP_AUDIO_FRAME_DUR_DEN;
}
if (payload_type < 0) {
payload_type = 96;
if (rate == 8000 && channels == 1) {
if (!strcmp(audio_codec, "GSM"))
payload_type = 3;
else if (!strcmp(audio_codec, "PCMA"))
payload_type = 8;
else if (!strcmp(audio_codec, "PCMU"))
payload_type = 0;
else if (!strcmp(audio_codec, "G729"))
payload_type = 18;
}
codec->payload_type = payload_type;
}
if (channels != 1)
LOGP(DMGCP, LOGL_NOTICE,
"Channels != 1 in SDP: '%s'\n", audio_name);
return 0;
}
void codecs_initialize(void *ctx, struct sdp_rtp_map *codecs, int used)
{
int i;
for (i = 0; i < used; ++i) {
switch (codecs[i].payload_type) {
case 0:
codecs[i].codec_name = "PCMU";
codecs[i].rate = 8000;
codecs[i].channels = 1;
break;
case 3:
codecs[i].codec_name = "GSM";
codecs[i].rate = 8000;
codecs[i].channels = 1;
break;
case 8:
codecs[i].codec_name = "PCMA";
codecs[i].rate = 8000;
codecs[i].channels = 1;
break;
case 18:
codecs[i].codec_name = "G729";
codecs[i].rate = 8000;
codecs[i].channels = 1;
break;
}
}
}
void codecs_update(void *ctx, struct sdp_rtp_map *codecs, int used, int payload, char *audio_name)
{
int i;
for (i = 0; i < used; ++i) {
char audio_codec[64];
int rate = -1;
int channels = -1;
if (codecs[i].payload_type != payload)
continue;
if (sscanf(audio_name, "%63[^/]/%d/%d",
audio_codec, &rate, &channels) < 1) {
LOGP(DMGCP, LOGL_ERROR, "Failed to parse '%s'\n", audio_name);
continue;
}
codecs[i].map_line = talloc_strdup(ctx, audio_name);
codecs[i].codec_name = talloc_strdup(ctx, audio_codec);
codecs[i].rate = rate;
codecs[i].channels = channels;
return;
}
LOGP(DMGCP, LOGL_ERROR, "Unconfigured PT(%d) with %s\n", payload, audio_name);
}
int is_codec_compatible(struct mgcp_endpoint *endp, struct sdp_rtp_map *codec)
{
char *bts_codec;
char audio_codec[64];
if (!codec->codec_name)
return 0;
/*
* GSM, GSM/8000 and GSM/8000/1 should all be compatible.. let's go
* by name first.
*/
bts_codec = endp->tcfg->audio_name;
if (sscanf(bts_codec, "%63[^/]/%*d/%*d", audio_codec) < 1)
return 0;
return strcasecmp(audio_codec, codec->codec_name) == 0;
}
int mgcp_parse_sdp_data(struct mgcp_endpoint *endp, struct mgcp_rtp_end *rtp, struct mgcp_parse_data *p)
{
struct sdp_rtp_map codecs[10];
int codecs_used = 0;
char *line;
int maxptime = -1;
int i;
int codecs_assigned = 0;
void *tmp_ctx = talloc_new(NULL);
memset(&codecs, 0, sizeof(codecs));
for_each_line(line, p->save) {
switch (line[0]) {
case 'o':
case 's':
case 't':
case 'v':
/* skip these SDP attributes */
break;
case 'a': {
int payload;
int ptime, ptime2 = 0;
char audio_name[64];
if (sscanf(line, "a=rtpmap:%d %63s",
&payload, audio_name) == 2) {
codecs_update(tmp_ctx, codecs, codecs_used, payload, audio_name);
} 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) {
maxptime = ptime2;
}
break;
}
case 'm': {
int port, rc;
rc = sscanf(line, "m=audio %d RTP/AVP %d %d %d %d %d %d %d %d %d %d",
&port,
&codecs[0].payload_type,
&codecs[1].payload_type,
&codecs[2].payload_type,
&codecs[3].payload_type,
&codecs[4].payload_type,
&codecs[5].payload_type,
&codecs[6].payload_type,
&codecs[7].payload_type,
&codecs[8].payload_type,
&codecs[9].payload_type);
if (rc >= 2) {
rtp->rtp_port = htons(port);
rtp->rtcp_port = htons(port + 1);
codecs_used = rc - 1;
codecs_initialize(tmp_ctx, codecs, codecs_used);
}
break;
}
case 'c': {
char ipv4[16];
if (sscanf(line, "c=IN IP4 %15s", ipv4) == 1) {
inet_aton(ipv4, &rtp->addr);
}
break;
}
default:
if (p->endp)
LOGP(DMGCP, LOGL_NOTICE,
"Unhandled SDP option: '%c'/%d on 0x%x\n",
line[0], line[0], ENDPOINT_NUMBER(p->endp));
else
LOGP(DMGCP, LOGL_NOTICE,
"Unhandled SDP option: '%c'/%d\n",
line[0], line[0]);
break;
}
}
/* Now select the primary and alt_codec */
for (i = 0; i < codecs_used && codecs_assigned < 2; ++i) {
struct mgcp_rtp_codec *codec = codecs_assigned == 0 ?
&rtp->codec : &rtp->alt_codec;
if (endp->tcfg->no_audio_transcoding &&
!is_codec_compatible(endp, &codecs[i])) {
LOGP(DMGCP, LOGL_NOTICE, "Skipping codec %s\n",
codecs[i].codec_name);
continue;
}
mgcp_set_audio_info(p->cfg, codec,
codecs[i].payload_type,
codecs[i].map_line);
codecs_assigned += 1;
}
if (codecs_assigned > 0) {
/* TODO/XXX: Store this per codec and derive it on use */
if (maxptime >= 0 && maxptime * rtp->codec.frame_duration_den >
rtp->codec.frame_duration_num * 1500) {
/* more than 1 frame */
rtp->packet_duration_ms = 0;
}
LOGP(DMGCP, LOGL_NOTICE,
"Got media info via SDP: port %d, payload %d (%s), "
"duration %d, addr %s\n",
ntohs(rtp->rtp_port), rtp->codec.payload_type,
rtp->codec.subtype_name ? rtp->codec.subtype_name : "unknown",
rtp->packet_duration_ms, inet_ntoa(rtp->addr));
}
talloc_free(tmp_ctx);
return codecs_assigned > 0;
}
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