diff options
Diffstat (limited to 'openbsc/src/libmgcp/mgcp_sdp.c')
| -rw-r--r-- | openbsc/src/libmgcp/mgcp_sdp.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/openbsc/src/libmgcp/mgcp_sdp.c b/openbsc/src/libmgcp/mgcp_sdp.c new file mode 100644 index 000000000..a10b3ac02 --- /dev/null +++ b/openbsc/src/libmgcp/mgcp_sdp.c @@ -0,0 +1,191 @@ +/* + * 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> + +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 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, "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; +} + + +int mgcp_parse_sdp_data(struct mgcp_rtp_end *rtp, struct mgcp_parse_data *p) +{ + char *line; + int found_media = 0; + /* TODO/XXX make it more generic */ + int audio_payload = -1; + int audio_payload_alt = -1; + + 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 (audio_payload == -1) + break; + + if (sscanf(line, "a=rtpmap:%d %63s", + &payload, audio_name) == 2) { + if (payload == audio_payload) + mgcp_set_audio_info(p->cfg, &rtp->codec, + payload, audio_name); + else if (payload == audio_payload_alt) + mgcp_set_audio_info(p->cfg, &rtp->alt_codec, + 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) { + /* TODO/XXX: Store this per codec and derive it on use */ + if (ptime2 * rtp->codec.frame_duration_den > + rtp->codec.frame_duration_num * 1500) + /* more than 1 frame */ + rtp->packet_duration_ms = 0; + } + break; + } + case 'm': { + int port, rc; + audio_payload = -1; + audio_payload_alt = -1; + + rc = sscanf(line, "m=audio %d RTP/AVP %d %d", + &port, &audio_payload, &audio_payload_alt); + if (rc >= 2) { + rtp->rtp_port = htons(port); + rtp->rtcp_port = htons(port + 1); + found_media = 1; + mgcp_set_audio_info(p->cfg, &rtp->codec, audio_payload, NULL); + if (rc == 3) + mgcp_set_audio_info(p->cfg, &rtp->alt_codec, + audio_payload_alt, NULL); + } + 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; + } + } + + if (found_media) + 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)); + + return found_media; +} + |