diff options
Diffstat (limited to 'src/libmgcp/mgcp_sdp.c')
-rw-r--r-- | src/libmgcp/mgcp_sdp.c | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/src/libmgcp/mgcp_sdp.c b/src/libmgcp/mgcp_sdp.c new file mode 100644 index 000000000..b64894496 --- /dev/null +++ b/src/libmgcp/mgcp_sdp.c @@ -0,0 +1,305 @@ +/* + * 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; +} + |