1/* 2 * Realmedia RTSP protocol (RDT) support. 3 * Copyright (c) 2007 Ronald S. Bultje 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file libavformat/rdt.c 24 * @brief Realmedia RTSP protocol (RDT) support 25 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net> 26 */ 27 28#include "avformat.h" 29#include "libavutil/avstring.h" 30#include "rtpdec.h" 31#include "rdt.h" 32#include "libavutil/base64.h" 33#include "libavutil/md5.h" 34#include "rm.h" 35#include "internal.h" 36#include "libavcodec/bitstream.h" 37 38struct RDTDemuxContext { 39 AVFormatContext *ic; /**< the containing (RTSP) demux context */ 40 /** Each RDT stream-set (represented by one RTSPStream) can contain 41 * multiple streams (of the same content, but with possibly different 42 * codecs/bitrates). Each such stream is represented by one AVStream 43 * in the AVFormatContext, and this variable points to the offset in 44 * that array such that the first is the first stream of this set. */ 45 AVStream **streams; 46 int n_streams; /**< streams with identifical content in this set */ 47 void *dynamic_protocol_context; 48 DynamicPayloadPacketHandlerProc parse_packet; 49 uint32_t prev_timestamp; 50 int prev_set_id, prev_stream_id; 51}; 52 53RDTDemuxContext * 54ff_rdt_parse_open(AVFormatContext *ic, int first_stream_of_set_idx, 55 void *priv_data, RTPDynamicProtocolHandler *handler) 56{ 57 RDTDemuxContext *s = av_mallocz(sizeof(RDTDemuxContext)); 58 if (!s) 59 return NULL; 60 61 s->ic = ic; 62 s->streams = &ic->streams[first_stream_of_set_idx]; 63 do { 64 s->n_streams++; 65 } while (first_stream_of_set_idx + s->n_streams < ic->nb_streams && 66 s->streams[s->n_streams]->priv_data == s->streams[0]->priv_data); 67 s->prev_set_id = -1; 68 s->prev_stream_id = -1; 69 s->prev_timestamp = -1; 70 s->parse_packet = handler->parse_packet; 71 s->dynamic_protocol_context = priv_data; 72 73 return s; 74} 75 76void 77ff_rdt_parse_close(RDTDemuxContext *s) 78{ 79 int i; 80 81 for (i = 1; i < s->n_streams; i++) 82 s->streams[i]->priv_data = NULL; 83 84 av_free(s); 85} 86 87struct PayloadContext { 88 AVFormatContext *rmctx; 89 RMStream *rmst[MAX_STREAMS]; 90 uint8_t *mlti_data; 91 unsigned int mlti_data_size; 92 char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE]; 93 int audio_pkt_cnt; /**< remaining audio packets in rmdec */ 94}; 95 96void 97ff_rdt_calc_response_and_checksum(char response[41], char chksum[9], 98 const char *challenge) 99{ 100 int ch_len = strlen (challenge), i; 101 unsigned char zres[16], 102 buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 }; 103#define XOR_TABLE_SIZE 37 104 const unsigned char xor_table[XOR_TABLE_SIZE] = { 105 0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53, 106 0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70, 107 0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09, 108 0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02, 109 0x10, 0x57, 0x05, 0x18, 0x54 }; 110 111 /* some (length) checks */ 112 if (ch_len == 40) /* what a hack... */ 113 ch_len = 32; 114 else if (ch_len > 56) 115 ch_len = 56; 116 memcpy(buf + 8, challenge, ch_len); 117 118 /* xor challenge bytewise with xor_table */ 119 for (i = 0; i < XOR_TABLE_SIZE; i++) 120 buf[8 + i] ^= xor_table[i]; 121 122 av_md5_sum(zres, buf, 64); 123 ff_data_to_hex(response, zres, 16); 124 for (i=0;i<32;i++) response[i] = tolower(response[i]); 125 126 /* add tail */ 127 strcpy (response + 32, "01d0a8e3"); 128 129 /* calculate checksum */ 130 for (i = 0; i < 8; i++) 131 chksum[i] = response[i * 4]; 132 chksum[8] = 0; 133} 134 135static int 136rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr) 137{ 138 ByteIOContext pb; 139 int size; 140 uint32_t tag; 141 142 /** 143 * Layout of the MLTI chunk: 144 * 4:MLTI 145 * 2:<number of streams> 146 * Then for each stream ([number_of_streams] times): 147 * 2:<mdpr index> 148 * 2:<number of mdpr chunks> 149 * Then for each mdpr chunk ([number_of_mdpr_chunks] times): 150 * 4:<size> 151 * [size]:<data> 152 * we skip MDPR chunks until we reach the one of the stream 153 * we're interested in, and forward that ([size]+[data]) to 154 * the RM demuxer to parse the stream-specific header data. 155 */ 156 if (!rdt->mlti_data) 157 return -1; 158 init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0, 159 NULL, NULL, NULL, NULL); 160 tag = get_le32(&pb); 161 if (tag == MKTAG('M', 'L', 'T', 'I')) { 162 int num, chunk_nr; 163 164 /* read index of MDPR chunk numbers */ 165 num = get_be16(&pb); 166 if (rule_nr < 0 || rule_nr >= num) 167 return -1; 168 url_fskip(&pb, rule_nr * 2); 169 chunk_nr = get_be16(&pb); 170 url_fskip(&pb, (num - 1 - rule_nr) * 2); 171 172 /* read MDPR chunks */ 173 num = get_be16(&pb); 174 if (chunk_nr >= num) 175 return -1; 176 while (chunk_nr--) 177 url_fskip(&pb, get_be32(&pb)); 178 size = get_be32(&pb); 179 } else { 180 size = rdt->mlti_data_size; 181 url_fseek(&pb, 0, SEEK_SET); 182 } 183 if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, rdt->rmst[st->index], size) < 0) 184 return -1; 185 186 return 0; 187} 188 189/** 190 * Actual data handling. 191 */ 192 193int 194ff_rdt_parse_header(const uint8_t *buf, int len, 195 int *pset_id, int *pseq_no, int *pstream_id, 196 int *pis_keyframe, uint32_t *ptimestamp) 197{ 198 GetBitContext gb; 199 int consumed = 0, set_id, seq_no, stream_id, is_keyframe, 200 len_included, need_reliable; 201 uint32_t timestamp; 202 203 /* skip status packets */ 204 while (len >= 5 && buf[1] == 0xFF /* status packet */) { 205 int pkt_len; 206 207 if (!(buf[0] & 0x80)) 208 return -1; /* not followed by a data packet */ 209 210 pkt_len = AV_RB16(buf+3); 211 buf += pkt_len; 212 len -= pkt_len; 213 consumed += pkt_len; 214 } 215 if (len < 16) 216 return -1; 217 /** 218 * Layout of the header (in bits): 219 * 1: len_included 220 * Flag indicating whether this header includes a length field; 221 * this can be used to concatenate multiple RDT packets in a 222 * single UDP/TCP data frame and is used to precede RDT data 223 * by stream status packets 224 * 1: need_reliable 225 * Flag indicating whether this header includes a "reliable 226 * sequence number"; these are apparently sequence numbers of 227 * data packets alone. For data packets, this flag is always 228 * set, according to the Real documentation [1] 229 * 5: set_id 230 * ID of a set of streams of identical content, possibly with 231 * different codecs or bitrates 232 * 1: is_reliable 233 * Flag set for certain streams deemed less tolerable for packet 234 * loss 235 * 16: seq_no 236 * Packet sequence number; if >=0xFF00, this is a non-data packet 237 * containing stream status info, the second byte indicates the 238 * type of status packet (see wireshark docs / source code [2]) 239 * if (len_included) { 240 * 16: packet_len 241 * } else { 242 * packet_len = remainder of UDP/TCP frame 243 * } 244 * 1: is_back_to_back 245 * Back-to-Back flag; used for timing, set for one in every 10 246 * packets, according to the Real documentation [1] 247 * 1: is_slow_data 248 * Slow-data flag; currently unused, according to Real docs [1] 249 * 5: stream_id 250 * ID of the stream within this particular set of streams 251 * 1: is_no_keyframe 252 * Non-keyframe flag (unset if packet belongs to a keyframe) 253 * 32: timestamp (PTS) 254 * if (set_id == 0x1F) { 255 * 16: set_id (extended set-of-streams ID; see set_id) 256 * } 257 * if (need_reliable) { 258 * 16: reliable_seq_no 259 * Reliable sequence number (see need_reliable) 260 * } 261 * if (stream_id == 0x3F) { 262 * 16: stream_id (extended stream ID; see stream_id) 263 * } 264 * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt 265 * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and 266 * http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c 267 */ 268 init_get_bits(&gb, buf, len << 3); 269 len_included = get_bits1(&gb); 270 need_reliable = get_bits1(&gb); 271 set_id = get_bits(&gb, 5); 272 skip_bits(&gb, 1); 273 seq_no = get_bits(&gb, 16); 274 if (len_included) 275 skip_bits(&gb, 16); 276 skip_bits(&gb, 2); 277 stream_id = get_bits(&gb, 5); 278 is_keyframe = !get_bits1(&gb); 279 timestamp = get_bits_long(&gb, 32); 280 if (set_id == 0x1f) 281 set_id = get_bits(&gb, 16); 282 if (need_reliable) 283 skip_bits(&gb, 16); 284 if (stream_id == 0x1f) 285 stream_id = get_bits(&gb, 16); 286 287 if (pset_id) *pset_id = set_id; 288 if (pseq_no) *pseq_no = seq_no; 289 if (pstream_id) *pstream_id = stream_id; 290 if (pis_keyframe) *pis_keyframe = is_keyframe; 291 if (ptimestamp) *ptimestamp = timestamp; 292 293 return consumed + (get_bits_count(&gb) >> 3); 294} 295 296/**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */ 297static int 298rdt_parse_packet (AVFormatContext *ctx, PayloadContext *rdt, AVStream *st, 299 AVPacket *pkt, uint32_t *timestamp, 300 const uint8_t *buf, int len, int flags) 301{ 302 int seq = 1, res; 303 ByteIOContext pb; 304 305 if (rdt->audio_pkt_cnt == 0) { 306 int pos; 307 308 init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL); 309 flags = (flags & RTP_FLAG_KEY) ? 2 : 0; 310 res = ff_rm_parse_packet (rdt->rmctx, &pb, st, rdt->rmst[st->index], len, pkt, 311 &seq, &flags, timestamp); 312 pos = url_ftell(&pb); 313 if (res < 0) 314 return res; 315 rdt->audio_pkt_cnt = res; 316 if (rdt->audio_pkt_cnt > 0 && 317 st->codec->codec_id == CODEC_ID_AAC) { 318 memcpy (rdt->buffer, buf + pos, len - pos); 319 rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0, 320 NULL, NULL, NULL, NULL); 321 } 322 } else { 323 rdt->audio_pkt_cnt = 324 ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb, 325 st, rdt->rmst[st->index], pkt); 326 if (rdt->audio_pkt_cnt == 0 && 327 st->codec->codec_id == CODEC_ID_AAC) 328 av_freep(&rdt->rmctx->pb); 329 } 330 pkt->stream_index = st->index; 331 pkt->pts = *timestamp; 332 333 return rdt->audio_pkt_cnt > 0; 334} 335 336int 337ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt, 338 const uint8_t *buf, int len) 339{ 340 int seq_no, flags = 0, stream_id, set_id, is_keyframe; 341 uint32_t timestamp; 342 int rv= 0; 343 344 if (!s->parse_packet) 345 return -1; 346 347 if (!buf && s->prev_stream_id != -1) { 348 /* return the next packets, if any */ 349 timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned.... 350 rv= s->parse_packet(s->ic, s->dynamic_protocol_context, 351 s->streams[s->prev_stream_id], 352 pkt, ×tamp, NULL, 0, flags); 353 return rv; 354 } 355 356 if (len < 12) 357 return -1; 358 rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, ×tamp); 359 if (rv < 0) 360 return rv; 361 if (is_keyframe && 362 (set_id != s->prev_set_id || timestamp != s->prev_timestamp || 363 stream_id != s->prev_stream_id)) { 364 flags |= RTP_FLAG_KEY; 365 s->prev_set_id = set_id; 366 s->prev_timestamp = timestamp; 367 } 368 s->prev_stream_id = stream_id; 369 buf += rv; 370 len -= rv; 371 372 if (s->prev_stream_id >= s->n_streams) { 373 s->prev_stream_id = -1; 374 return -1; 375 } 376 377 rv = s->parse_packet(s->ic, s->dynamic_protocol_context, 378 s->streams[s->prev_stream_id], 379 pkt, ×tamp, buf, len, flags); 380 381 return rv; 382} 383 384void 385ff_rdt_subscribe_rule (char *cmd, int size, 386 int stream_nr, int rule_nr) 387{ 388 av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d", 389 stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1); 390} 391 392static unsigned char * 393rdt_parse_b64buf (unsigned int *target_len, const char *p) 394{ 395 unsigned char *target; 396 int len = strlen(p); 397 if (*p == '\"') { 398 p++; 399 len -= 2; /* skip embracing " at start/end */ 400 } 401 *target_len = len * 3 / 4; 402 target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE); 403 av_base64_decode(target, p, *target_len); 404 return target; 405} 406 407static int 408rdt_parse_sdp_line (AVFormatContext *s, int st_index, 409 PayloadContext *rdt, const char *line) 410{ 411 AVStream *stream = s->streams[st_index]; 412 const char *p = line; 413 414 if (av_strstart(p, "OpaqueData:buffer;", &p)) { 415 rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p); 416 } else if (av_strstart(p, "StartTime:integer;", &p)) 417 stream->first_dts = atoi(p); 418 else if (av_strstart(p, "ASMRuleBook:string;", &p)) { 419 int n = st_index, first = -1; 420 421 for (n = 0; n < s->nb_streams; n++) 422 if (s->streams[n]->priv_data == stream->priv_data) { 423 if (first == -1) first = n; 424 rdt->rmst[s->streams[n]->index] = ff_rm_alloc_rmstream(); 425 rdt_load_mdpr(rdt, s->streams[n], (n - first) * 2); 426 427 if (s->streams[n]->codec->codec_id == CODEC_ID_AAC) 428 s->streams[n]->codec->frame_size = 1; // FIXME 429 } 430 } 431 432 return 0; 433} 434 435static void 436real_parse_asm_rule(AVStream *st, const char *p, const char *end) 437{ 438 do { 439 /* can be either averagebandwidth= or AverageBandwidth= */ 440 if (sscanf(p, " %*1[Aa]verage%*1[Bb]andwidth=%d", &st->codec->bit_rate) == 1) 441 break; 442 if (!(p = strchr(p, ',')) || p > end) 443 p = end; 444 p++; 445 } while (p < end); 446} 447 448static AVStream * 449add_dstream(AVFormatContext *s, AVStream *orig_st) 450{ 451 AVStream *st; 452 453 if (!(st = av_new_stream(s, 0))) 454 return NULL; 455 st->codec->codec_type = orig_st->codec->codec_type; 456 st->priv_data = orig_st->priv_data; 457 st->first_dts = orig_st->first_dts; 458 459 return st; 460} 461 462static void 463real_parse_asm_rulebook(AVFormatContext *s, AVStream *orig_st, 464 const char *p) 465{ 466 const char *end; 467 int n_rules, odd = 0; 468 AVStream *st; 469 470 /** 471 * The ASMRuleBook contains a list of comma-separated strings per rule, 472 * and each rule is separated by a ;. The last one also has a ; at the 473 * end so we can use it as delimiter. 474 * Every rule occurs twice, once for when the RTSP packet header marker 475 * is set and once for if it isn't. We only read the first because we 476 * don't care much (that's what the "odd" variable is for). 477 * Each rule contains a set of one or more statements, optionally 478 * preceeded by a single condition. If there's a condition, the rule 479 * starts with a '#'. Multiple conditions are merged between brackets, 480 * so there are never multiple conditions spread out over separate 481 * statements. Generally, these conditions are bitrate limits (min/max) 482 * for multi-bitrate streams. 483 */ 484 if (*p == '\"') p++; 485 for (n_rules = 0; s->nb_streams < MAX_STREAMS;) { 486 if (!(end = strchr(p, ';'))) 487 break; 488 if (!odd && end != p) { 489 if (n_rules > 0) 490 st = add_dstream(s, orig_st); 491 else 492 st = orig_st; 493 real_parse_asm_rule(st, p, end); 494 n_rules++; 495 } 496 p = end + 1; 497 odd ^= 1; 498 } 499} 500 501void 502ff_real_parse_sdp_a_line (AVFormatContext *s, int stream_index, 503 const char *line) 504{ 505 const char *p = line; 506 507 if (av_strstart(p, "ASMRuleBook:string;", &p)) 508 real_parse_asm_rulebook(s, s->streams[stream_index], p); 509} 510 511static PayloadContext * 512rdt_new_extradata (void) 513{ 514 PayloadContext *rdt = av_mallocz(sizeof(PayloadContext)); 515 516 av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL); 517 518 return rdt; 519} 520 521static void 522rdt_free_extradata (PayloadContext *rdt) 523{ 524 int i; 525 526 for (i = 0; i < MAX_STREAMS; i++) 527 if (rdt->rmst[i]) { 528 ff_rm_free_rmstream(rdt->rmst[i]); 529 av_freep(&rdt->rmst[i]); 530 } 531 if (rdt->rmctx) 532 av_close_input_stream(rdt->rmctx); 533 av_freep(&rdt->mlti_data); 534 av_free(rdt); 535} 536 537#define RDT_HANDLER(n, s, t) \ 538static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \ 539 s, \ 540 t, \ 541 CODEC_ID_NONE, \ 542 rdt_parse_sdp_line, \ 543 rdt_new_extradata, \ 544 rdt_free_extradata, \ 545 rdt_parse_packet \ 546}; 547 548RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO); 549RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO); 550RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO); 551RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO); 552 553void av_register_rdt_dynamic_payload_handlers(void) 554{ 555 ff_register_dynamic_payload_handler(&ff_rdt_video_handler); 556 ff_register_dynamic_payload_handler(&ff_rdt_audio_handler); 557 ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler); 558 ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler); 559} 560