mgcp: Move the SDP handling into a separate file/module
The SDP file handling will get more complicated in terms of
codec selection so let's remove it from the protocol handling
before we start blowing it up in size.
diff --git a/openbsc/src/libmgcp/mgcp_sdp.c b/openbsc/src/libmgcp/mgcp_sdp.c
new file mode 100644
index 0000000..a10b3ac
--- /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;
+}
+