Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Some SDP file parsing... |
| 3 | * |
| 4 | * (C) 2009-2015 by Holger Hans Peter Freyther <zecke@selfish.org> |
| 5 | * (C) 2009-2014 by On-Waves |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU Affero General Public License as published by |
| 10 | * the Free Software Foundation; either version 3 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU Affero General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Affero General Public License |
| 19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | * |
| 21 | */ |
| 22 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 23 | #include <osmocom/core/msgb.h> |
Philipp Maier | 87bd9be | 2017-08-22 16:35:41 +0200 | [diff] [blame] | 24 | #include <osmocom/mgcp/mgcp.h> |
| 25 | #include <osmocom/mgcp/mgcp_internal.h> |
| 26 | #include <osmocom/mgcp/mgcp_msg.h> |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 27 | |
| 28 | #include <errno.h> |
| 29 | |
| 30 | struct sdp_rtp_map { |
| 31 | /* the type */ |
| 32 | int payload_type; |
| 33 | /* null, static or later dynamic codec name */ |
| 34 | char *codec_name; |
| 35 | /* A pointer to the original line for later parsing */ |
| 36 | char *map_line; |
| 37 | |
| 38 | int rate; |
| 39 | int channels; |
| 40 | }; |
| 41 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 42 | /*! Set codec configuration depending on payload type and codec name. |
| 43 | * \param[in] ctx talloc context. |
| 44 | * \param[out] codec configuration (caller provided memory). |
| 45 | * \param[in] payload_type codec type id (e.g. 3 for GSM, -1 when undefined). |
| 46 | * \param[in] audio_name audio codec name (e.g. "GSM/8000/1"). |
| 47 | * \returns 0 on success, -1 on failure. */ |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 48 | int mgcp_set_audio_info(void *ctx, struct mgcp_rtp_codec *codec, |
| 49 | int payload_type, const char *audio_name) |
| 50 | { |
| 51 | int rate = codec->rate; |
| 52 | int channels = codec->channels; |
| 53 | char audio_codec[64]; |
| 54 | |
| 55 | talloc_free(codec->subtype_name); |
| 56 | codec->subtype_name = NULL; |
| 57 | talloc_free(codec->audio_name); |
| 58 | codec->audio_name = NULL; |
| 59 | |
| 60 | if (payload_type != PTYPE_UNDEFINED) |
| 61 | codec->payload_type = payload_type; |
| 62 | |
| 63 | if (!audio_name) { |
| 64 | switch (payload_type) { |
| 65 | case 0: audio_name = "PCMU/8000/1"; break; |
| 66 | case 3: audio_name = "GSM/8000/1"; break; |
| 67 | case 8: audio_name = "PCMA/8000/1"; break; |
| 68 | case 18: audio_name = "G729/8000/1"; break; |
| 69 | default: |
| 70 | /* Payload type is unknown, don't change rate and |
| 71 | * channels. */ |
| 72 | /* TODO: return value? */ |
| 73 | return 0; |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | if (sscanf(audio_name, "%63[^/]/%d/%d", |
| 78 | audio_codec, &rate, &channels) < 1) |
| 79 | return -EINVAL; |
| 80 | |
| 81 | codec->rate = rate; |
| 82 | codec->channels = channels; |
| 83 | codec->subtype_name = talloc_strdup(ctx, audio_codec); |
| 84 | codec->audio_name = talloc_strdup(ctx, audio_name); |
| 85 | |
| 86 | if (!strcmp(audio_codec, "G729")) { |
| 87 | codec->frame_duration_num = 10; |
| 88 | codec->frame_duration_den = 1000; |
| 89 | } else { |
| 90 | codec->frame_duration_num = DEFAULT_RTP_AUDIO_FRAME_DUR_NUM; |
| 91 | codec->frame_duration_den = DEFAULT_RTP_AUDIO_FRAME_DUR_DEN; |
| 92 | } |
| 93 | |
| 94 | if (payload_type < 0) { |
| 95 | payload_type = 96; |
| 96 | if (rate == 8000 && channels == 1) { |
| 97 | if (!strcmp(audio_codec, "GSM")) |
| 98 | payload_type = 3; |
| 99 | else if (!strcmp(audio_codec, "PCMA")) |
| 100 | payload_type = 8; |
| 101 | else if (!strcmp(audio_codec, "PCMU")) |
| 102 | payload_type = 0; |
| 103 | else if (!strcmp(audio_codec, "G729")) |
| 104 | payload_type = 18; |
| 105 | } |
| 106 | |
| 107 | codec->payload_type = payload_type; |
| 108 | } |
| 109 | |
| 110 | if (channels != 1) |
| 111 | LOGP(DLMGCP, LOGL_NOTICE, |
| 112 | "Channels != 1 in SDP: '%s'\n", audio_name); |
| 113 | |
| 114 | return 0; |
| 115 | } |
| 116 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 117 | static void codecs_initialize(void *ctx, struct sdp_rtp_map *codecs, int used) |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 118 | { |
| 119 | int i; |
| 120 | |
| 121 | for (i = 0; i < used; ++i) { |
| 122 | switch (codecs[i].payload_type) { |
| 123 | case 0: |
| 124 | codecs[i].codec_name = "PCMU"; |
| 125 | codecs[i].rate = 8000; |
| 126 | codecs[i].channels = 1; |
| 127 | break; |
| 128 | case 3: |
| 129 | codecs[i].codec_name = "GSM"; |
| 130 | codecs[i].rate = 8000; |
| 131 | codecs[i].channels = 1; |
| 132 | break; |
| 133 | case 8: |
| 134 | codecs[i].codec_name = "PCMA"; |
| 135 | codecs[i].rate = 8000; |
| 136 | codecs[i].channels = 1; |
| 137 | break; |
| 138 | case 18: |
| 139 | codecs[i].codec_name = "G729"; |
| 140 | codecs[i].rate = 8000; |
| 141 | codecs[i].channels = 1; |
| 142 | break; |
| 143 | } |
| 144 | } |
| 145 | } |
| 146 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 147 | static void codecs_update(void *ctx, struct sdp_rtp_map *codecs, int used, |
| 148 | int payload, const char *audio_name) |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 149 | { |
| 150 | int i; |
| 151 | |
| 152 | for (i = 0; i < used; ++i) { |
| 153 | char audio_codec[64]; |
| 154 | int rate = -1; |
| 155 | int channels = -1; |
| 156 | if (codecs[i].payload_type != payload) |
| 157 | continue; |
| 158 | if (sscanf(audio_name, "%63[^/]/%d/%d", |
| 159 | audio_codec, &rate, &channels) < 1) { |
| 160 | LOGP(DLMGCP, LOGL_ERROR, "Failed to parse '%s'\n", audio_name); |
| 161 | continue; |
| 162 | } |
| 163 | |
| 164 | codecs[i].map_line = talloc_strdup(ctx, audio_name); |
| 165 | codecs[i].codec_name = talloc_strdup(ctx, audio_codec); |
| 166 | codecs[i].rate = rate; |
| 167 | codecs[i].channels = channels; |
| 168 | return; |
| 169 | } |
| 170 | |
| 171 | LOGP(DLMGCP, LOGL_ERROR, "Unconfigured PT(%d) with %s\n", payload, audio_name); |
| 172 | } |
| 173 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 174 | /* Check if the codec matches what is set up in the trunk config */ |
| 175 | static int is_codec_compatible(const struct mgcp_endpoint *endp, |
| 176 | const struct sdp_rtp_map *codec) |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 177 | { |
Philipp Maier | e472b4e | 2017-10-18 11:38:17 +0200 | [diff] [blame^] | 178 | char *codec_str; |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 179 | char audio_codec[64]; |
| 180 | |
| 181 | if (!codec->codec_name) |
| 182 | return 0; |
| 183 | |
| 184 | /* |
| 185 | * GSM, GSM/8000 and GSM/8000/1 should all be compatible.. let's go |
| 186 | * by name first. |
| 187 | */ |
Philipp Maier | e472b4e | 2017-10-18 11:38:17 +0200 | [diff] [blame^] | 188 | codec_str = endp->tcfg->audio_name; |
| 189 | if (sscanf(codec_str, "%63[^/]/%*d/%*d", audio_codec) < 1) |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 190 | return 0; |
| 191 | |
| 192 | return strcasecmp(audio_codec, codec->codec_name) == 0; |
| 193 | } |
| 194 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 195 | /*! Analyze SDP input string. |
| 196 | * \param[in] endp trunk endpoint. |
| 197 | * \param[out] conn associated rtp connection. |
| 198 | * \param[out] caller provided memory to store the parsing results. |
| 199 | * \returns 0 on success, -1 on failure. |
| 200 | * |
| 201 | * Note: In conn (conn->end) the function returns the packet duration, |
| 202 | * the rtp port and the rtcp port */ |
| 203 | int mgcp_parse_sdp_data(const struct mgcp_endpoint *endp, |
| 204 | struct mgcp_conn_rtp *conn, |
| 205 | struct mgcp_parse_data *p) |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 206 | { |
| 207 | struct sdp_rtp_map codecs[10]; |
| 208 | int codecs_used = 0; |
| 209 | char *line; |
| 210 | int maxptime = -1; |
| 211 | int i; |
| 212 | int codecs_assigned = 0; |
| 213 | void *tmp_ctx = talloc_new(NULL); |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 214 | struct mgcp_rtp_end *rtp; |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 215 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 216 | OSMO_ASSERT(endp); |
| 217 | OSMO_ASSERT(conn); |
| 218 | OSMO_ASSERT(p); |
| 219 | |
| 220 | rtp = &conn->end; |
Neels Hofmeyr | f83ec56 | 2017-09-07 19:18:40 +0200 | [diff] [blame] | 221 | memset(&codecs, 0, sizeof(codecs)); |
| 222 | |
| 223 | for_each_line(line, p->save) { |
| 224 | switch (line[0]) { |
| 225 | case 'o': |
| 226 | case 's': |
| 227 | case 't': |
| 228 | case 'v': |
| 229 | /* skip these SDP attributes */ |
| 230 | break; |
| 231 | case 'a': { |
| 232 | int payload; |
| 233 | int ptime, ptime2 = 0; |
| 234 | char audio_name[64]; |
| 235 | |
| 236 | |
| 237 | if (sscanf(line, "a=rtpmap:%d %63s", |
| 238 | &payload, audio_name) == 2) { |
| 239 | codecs_update(tmp_ctx, codecs, codecs_used, payload, audio_name); |
| 240 | } else if (sscanf(line, "a=ptime:%d-%d", |
| 241 | &ptime, &ptime2) >= 1) { |
| 242 | if (ptime2 > 0 && ptime2 != ptime) |
| 243 | rtp->packet_duration_ms = 0; |
| 244 | else |
| 245 | rtp->packet_duration_ms = ptime; |
| 246 | } else if (sscanf(line, "a=maxptime:%d", &ptime2) == 1) { |
| 247 | maxptime = ptime2; |
| 248 | } |
| 249 | break; |
| 250 | } |
| 251 | case 'm': { |
| 252 | int port, rc; |
| 253 | |
| 254 | rc = sscanf(line, "m=audio %d RTP/AVP %d %d %d %d %d %d %d %d %d %d", |
| 255 | &port, |
| 256 | &codecs[0].payload_type, |
| 257 | &codecs[1].payload_type, |
| 258 | &codecs[2].payload_type, |
| 259 | &codecs[3].payload_type, |
| 260 | &codecs[4].payload_type, |
| 261 | &codecs[5].payload_type, |
| 262 | &codecs[6].payload_type, |
| 263 | &codecs[7].payload_type, |
| 264 | &codecs[8].payload_type, |
| 265 | &codecs[9].payload_type); |
| 266 | if (rc >= 2) { |
| 267 | rtp->rtp_port = htons(port); |
| 268 | rtp->rtcp_port = htons(port + 1); |
| 269 | codecs_used = rc - 1; |
| 270 | codecs_initialize(tmp_ctx, codecs, codecs_used); |
| 271 | } |
| 272 | break; |
| 273 | } |
| 274 | case 'c': { |
| 275 | char ipv4[16]; |
| 276 | |
| 277 | if (sscanf(line, "c=IN IP4 %15s", ipv4) == 1) { |
| 278 | inet_aton(ipv4, &rtp->addr); |
| 279 | } |
| 280 | break; |
| 281 | } |
| 282 | default: |
| 283 | if (p->endp) |
| 284 | LOGP(DLMGCP, LOGL_NOTICE, |
| 285 | "Unhandled SDP option: '%c'/%d on 0x%x\n", |
| 286 | line[0], line[0], ENDPOINT_NUMBER(p->endp)); |
| 287 | else |
| 288 | LOGP(DLMGCP, LOGL_NOTICE, |
| 289 | "Unhandled SDP option: '%c'/%d\n", |
| 290 | line[0], line[0]); |
| 291 | break; |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | /* Now select the primary and alt_codec */ |
| 296 | for (i = 0; i < codecs_used && codecs_assigned < 2; ++i) { |
| 297 | struct mgcp_rtp_codec *codec = codecs_assigned == 0 ? |
| 298 | &rtp->codec : &rtp->alt_codec; |
| 299 | |
| 300 | if (endp->tcfg->no_audio_transcoding && |
| 301 | !is_codec_compatible(endp, &codecs[i])) { |
| 302 | LOGP(DLMGCP, LOGL_NOTICE, "Skipping codec %s\n", |
| 303 | codecs[i].codec_name); |
| 304 | continue; |
| 305 | } |
| 306 | |
| 307 | mgcp_set_audio_info(p->cfg, codec, |
| 308 | codecs[i].payload_type, |
| 309 | codecs[i].map_line); |
| 310 | codecs_assigned += 1; |
| 311 | } |
| 312 | |
| 313 | if (codecs_assigned > 0) { |
| 314 | /* TODO/XXX: Store this per codec and derive it on use */ |
| 315 | if (maxptime >= 0 && maxptime * rtp->codec.frame_duration_den > |
| 316 | rtp->codec.frame_duration_num * 1500) { |
| 317 | /* more than 1 frame */ |
| 318 | rtp->packet_duration_ms = 0; |
| 319 | } |
| 320 | |
| 321 | LOGP(DLMGCP, LOGL_NOTICE, |
| 322 | "Got media info via SDP: port %d, payload %d (%s), " |
| 323 | "duration %d, addr %s\n", |
| 324 | ntohs(rtp->rtp_port), rtp->codec.payload_type, |
| 325 | rtp->codec.subtype_name ? rtp->codec.subtype_name : "unknown", |
| 326 | rtp->packet_duration_ms, inet_ntoa(rtp->addr)); |
| 327 | } |
| 328 | |
| 329 | talloc_free(tmp_ctx); |
| 330 | return codecs_assigned > 0; |
| 331 | } |
| 332 | |
Philipp Maier | 8970c49 | 2017-10-11 13:33:42 +0200 | [diff] [blame] | 333 | /*! Generate SDP response string. |
| 334 | * \param[in] endp trunk endpoint. |
| 335 | * \param[in] conn associated rtp connection. |
| 336 | * \param[out] sdp msg buffer to append resulting SDP string data. |
| 337 | * \param[in] addr IPV4 address string (e.g. 192.168.100.1). |
| 338 | * \returns 0 on success, -1 on failure. */ |
| 339 | int mgcp_write_response_sdp(const struct mgcp_endpoint *endp, |
| 340 | const struct mgcp_conn_rtp *conn, struct msgb *sdp, |
| 341 | const char *addr) |
| 342 | { |
| 343 | const char *fmtp_extra; |
| 344 | const char *audio_name; |
| 345 | int payload_type; |
| 346 | int rc; |
| 347 | |
| 348 | OSMO_ASSERT(endp); |
| 349 | OSMO_ASSERT(conn); |
| 350 | OSMO_ASSERT(sdp); |
| 351 | OSMO_ASSERT(addr); |
| 352 | |
| 353 | /* FIXME: constify endp and conn args in get_net_donwlink_format_cb() */ |
| 354 | endp->cfg->get_net_downlink_format_cb((struct mgcp_endpoint *)endp, |
| 355 | &payload_type, &audio_name, |
| 356 | &fmtp_extra, |
| 357 | (struct mgcp_conn_rtp *)conn); |
| 358 | |
| 359 | rc = msgb_printf(sdp, |
| 360 | "v=0\r\n" |
| 361 | "o=- %u 23 IN IP4 %s\r\n" |
| 362 | "s=-\r\n" |
| 363 | "c=IN IP4 %s\r\n" |
| 364 | "t=0 0\r\n", conn->conn->id, addr, addr); |
| 365 | |
| 366 | if (rc < 0) |
| 367 | goto buffer_too_small; |
| 368 | |
| 369 | if (payload_type >= 0) { |
| 370 | rc = msgb_printf(sdp, "m=audio %d RTP/AVP %d\r\n", |
| 371 | conn->end.local_port, payload_type); |
| 372 | if (rc < 0) |
| 373 | goto buffer_too_small; |
| 374 | |
| 375 | if (audio_name && endp->tcfg->audio_send_name) { |
| 376 | rc = msgb_printf(sdp, "a=rtpmap:%d %s\r\n", |
| 377 | payload_type, audio_name); |
| 378 | |
| 379 | if (rc < 0) |
| 380 | goto buffer_too_small; |
| 381 | } |
| 382 | |
| 383 | if (fmtp_extra) { |
| 384 | rc = msgb_printf(sdp, "%s\r\n", fmtp_extra); |
| 385 | |
| 386 | if (rc < 0) |
| 387 | goto buffer_too_small; |
| 388 | } |
| 389 | } |
| 390 | if (conn->end.packet_duration_ms > 0 && endp->tcfg->audio_send_ptime) { |
| 391 | rc = msgb_printf(sdp, "a=ptime:%u\r\n", |
| 392 | conn->end.packet_duration_ms); |
| 393 | if (rc < 0) |
| 394 | goto buffer_too_small; |
| 395 | } |
| 396 | |
| 397 | return 0; |
| 398 | |
| 399 | buffer_too_small: |
| 400 | LOGP(DLMGCP, LOGL_ERROR, "SDP messagebuffer too small\n"); |
| 401 | return -1; |
| 402 | } |