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-rw-r--r--src/libmgcp/mgcp_sdp.c305
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;
+}
+
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