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