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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
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
22
/**
23
 * @file
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/get_bits.h"
37

    
38
struct 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

    
53
RDTDemuxContext *
54
ff_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]->id == s->streams[0]->id);
67
    s->prev_set_id    = -1;
68
    s->prev_stream_id = -1;
69
    s->prev_timestamp = -1;
70
    s->parse_packet = handler ? handler->parse_packet : NULL;
71
    s->dynamic_protocol_context = priv_data;
72

    
73
    return s;
74
}
75

    
76
void
77
ff_rdt_parse_close(RDTDemuxContext *s)
78
{
79
    av_free(s);
80
}
81

    
82
struct PayloadContext {
83
    AVFormatContext *rmctx;
84
    int nb_rmst;
85
    RMStream **rmst;
86
    uint8_t *mlti_data;
87
    unsigned int mlti_data_size;
88
    char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
89
    int audio_pkt_cnt; /**< remaining audio packets in rmdec */
90
};
91

    
92
void
93
ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
94
                                  const char *challenge)
95
{
96
    int ch_len = strlen (challenge), i;
97
    unsigned char zres[16],
98
        buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
99
#define XOR_TABLE_SIZE 37
100
    const unsigned char xor_table[XOR_TABLE_SIZE] = {
101
        0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
102
        0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
103
        0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
104
        0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
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        0x10, 0x57, 0x05, 0x18, 0x54 };
106

    
107
    /* some (length) checks */
108
    if (ch_len == 40) /* what a hack... */
109
        ch_len = 32;
110
    else if (ch_len > 56)
111
        ch_len = 56;
112
    memcpy(buf + 8, challenge, ch_len);
113

    
114
    /* xor challenge bytewise with xor_table */
115
    for (i = 0; i < XOR_TABLE_SIZE; i++)
116
        buf[8 + i] ^= xor_table[i];
117

    
118
    av_md5_sum(zres, buf, 64);
119
    ff_data_to_hex(response, zres, 16, 1);
120

    
121
    /* add tail */
122
    strcpy (response + 32, "01d0a8e3");
123

    
124
    /* calculate checksum */
125
    for (i = 0; i < 8; i++)
126
        chksum[i] = response[i * 4];
127
    chksum[8] = 0;
128
}
129

    
130
static int
131
rdt_load_mdpr (PayloadContext *rdt, AVStream *st, int rule_nr)
132
{
133
    ByteIOContext pb;
134
    int size;
135
    uint32_t tag;
136

    
137
    /**
138
     * Layout of the MLTI chunk:
139
     * 4: MLTI
140
     * 2: number of streams
141
     * Then for each stream ([number_of_streams] times):
142
     *     2: mdpr index
143
     * 2: number of mdpr chunks
144
     * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
145
     *     4: size
146
     *     [size]: data
147
     * we skip MDPR chunks until we reach the one of the stream
148
     * we're interested in, and forward that ([size]+[data]) to
149
     * the RM demuxer to parse the stream-specific header data.
150
     */
151
    if (!rdt->mlti_data)
152
        return -1;
153
    init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
154
                  NULL, NULL, NULL, NULL);
155
    tag = get_le32(&pb);
156
    if (tag == MKTAG('M', 'L', 'T', 'I')) {
157
        int num, chunk_nr;
158

    
159
        /* read index of MDPR chunk numbers */
160
        num = get_be16(&pb);
161
        if (rule_nr < 0 || rule_nr >= num)
162
            return -1;
163
        url_fskip(&pb, rule_nr * 2);
164
        chunk_nr = get_be16(&pb);
165
        url_fskip(&pb, (num - 1 - rule_nr) * 2);
166

    
167
        /* read MDPR chunks */
168
        num = get_be16(&pb);
169
        if (chunk_nr >= num)
170
            return -1;
171
        while (chunk_nr--)
172
            url_fskip(&pb, get_be32(&pb));
173
        size = get_be32(&pb);
174
    } else {
175
        size = rdt->mlti_data_size;
176
        url_fseek(&pb, 0, SEEK_SET);
177
    }
178
    if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, rdt->rmst[st->index], size) < 0)
179
        return -1;
180

    
181
    return 0;
182
}
183

    
184
/**
185
 * Actual data handling.
186
 */
187

    
188
int
189
ff_rdt_parse_header(const uint8_t *buf, int len,
190
                    int *pset_id, int *pseq_no, int *pstream_id,
191
                    int *pis_keyframe, uint32_t *ptimestamp)
192
{
193
    GetBitContext gb;
194
    int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
195
        len_included, need_reliable;
196
    uint32_t timestamp;
197

    
198
    /* skip status packets */
199
    while (len >= 5 && buf[1] == 0xFF /* status packet */) {
200
        int pkt_len;
201

    
202
        if (!(buf[0] & 0x80))
203
            return -1; /* not followed by a data packet */
204

    
205
        pkt_len = AV_RB16(buf+3);
206
        buf += pkt_len;
207
        len -= pkt_len;
208
        consumed += pkt_len;
209
    }
210
    if (len < 16)
211
        return -1;
212
    /**
213
     * Layout of the header (in bits):
214
     * 1:  len_included
215
     *     Flag indicating whether this header includes a length field;
216
     *     this can be used to concatenate multiple RDT packets in a
217
     *     single UDP/TCP data frame and is used to precede RDT data
218
     *     by stream status packets
219
     * 1:  need_reliable
220
     *     Flag indicating whether this header includes a "reliable
221
     *     sequence number"; these are apparently sequence numbers of
222
     *     data packets alone. For data packets, this flag is always
223
     *     set, according to the Real documentation [1]
224
     * 5:  set_id
225
     *     ID of a set of streams of identical content, possibly with
226
     *     different codecs or bitrates
227
     * 1:  is_reliable
228
     *     Flag set for certain streams deemed less tolerable for packet
229
     *     loss
230
     * 16: seq_no
231
     *     Packet sequence number; if >=0xFF00, this is a non-data packet
232
     *     containing stream status info, the second byte indicates the
233
     *     type of status packet (see wireshark docs / source code [2])
234
     * if (len_included) {
235
     *     16: packet_len
236
     * } else {
237
     *     packet_len = remainder of UDP/TCP frame
238
     * }
239
     * 1:  is_back_to_back
240
     *     Back-to-Back flag; used for timing, set for one in every 10
241
     *     packets, according to the Real documentation [1]
242
     * 1:  is_slow_data
243
     *     Slow-data flag; currently unused, according to Real docs [1]
244
     * 5:  stream_id
245
     *     ID of the stream within this particular set of streams
246
     * 1:  is_no_keyframe
247
     *     Non-keyframe flag (unset if packet belongs to a keyframe)
248
     * 32: timestamp (PTS)
249
     * if (set_id == 0x1F) {
250
     *     16: set_id (extended set-of-streams ID; see set_id)
251
     * }
252
     * if (need_reliable) {
253
     *     16: reliable_seq_no
254
     *         Reliable sequence number (see need_reliable)
255
     * }
256
     * if (stream_id == 0x3F) {
257
     *     16: stream_id (extended stream ID; see stream_id)
258
     * }
259
     * [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
260
     * [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
261
     *     http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
262
     */
263
    init_get_bits(&gb, buf, len << 3);
264
    len_included  = get_bits1(&gb);
265
    need_reliable = get_bits1(&gb);
266
    set_id        = get_bits(&gb, 5);
267
    skip_bits(&gb, 1);
268
    seq_no        = get_bits(&gb, 16);
269
    if (len_included)
270
        skip_bits(&gb, 16);
271
    skip_bits(&gb, 2);
272
    stream_id     = get_bits(&gb, 5);
273
    is_keyframe   = !get_bits1(&gb);
274
    timestamp     = get_bits_long(&gb, 32);
275
    if (set_id == 0x1f)
276
        set_id    = get_bits(&gb, 16);
277
    if (need_reliable)
278
        skip_bits(&gb, 16);
279
    if (stream_id == 0x1f)
280
        stream_id = get_bits(&gb, 16);
281

    
282
    if (pset_id)      *pset_id      = set_id;
283
    if (pseq_no)      *pseq_no      = seq_no;
284
    if (pstream_id)   *pstream_id   = stream_id;
285
    if (pis_keyframe) *pis_keyframe = is_keyframe;
286
    if (ptimestamp)   *ptimestamp   = timestamp;
287

    
288
    return consumed + (get_bits_count(&gb) >> 3);
289
}
290

    
291
/**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
292
static int
293
rdt_parse_packet (AVFormatContext *ctx, PayloadContext *rdt, AVStream *st,
294
                  AVPacket *pkt, uint32_t *timestamp,
295
                  const uint8_t *buf, int len, int flags)
296
{
297
    int seq = 1, res;
298
    ByteIOContext pb;
299

    
300
    if (rdt->audio_pkt_cnt == 0) {
301
        int pos;
302

    
303
        init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
304
        flags = (flags & RTP_FLAG_KEY) ? 2 : 0;
305
        res = ff_rm_parse_packet (rdt->rmctx, &pb, st, rdt->rmst[st->index], len, pkt,
306
                                  &seq, flags, *timestamp);
307
        pos = url_ftell(&pb);
308
        if (res < 0)
309
            return res;
310
        if (res > 0) {
311
            if (st->codec->codec_id == CODEC_ID_AAC) {
312
                memcpy (rdt->buffer, buf + pos, len - pos);
313
                rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
314
                                                    NULL, NULL, NULL, NULL);
315
            }
316
            goto get_cache;
317
        }
318
    } else {
319
get_cache:
320
        rdt->audio_pkt_cnt =
321
            ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb,
322
                                  st, rdt->rmst[st->index], pkt);
323
        if (rdt->audio_pkt_cnt == 0 &&
324
            st->codec->codec_id == CODEC_ID_AAC)
325
            av_freep(&rdt->rmctx->pb);
326
    }
327
    pkt->stream_index = st->index;
328
    pkt->pts = *timestamp;
329

    
330
    return rdt->audio_pkt_cnt > 0;
331
}
332

    
333
int
334
ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
335
                    uint8_t **bufptr, int len)
336
{
337
    uint8_t *buf = bufptr ? *bufptr : NULL;
338
    int seq_no, flags = 0, stream_id, set_id, is_keyframe;
339
    uint32_t timestamp;
340
    int rv= 0;
341

    
342
    if (!s->parse_packet)
343
        return -1;
344

    
345
    if (!buf && s->prev_stream_id != -1) {
346
        /* return the next packets, if any */
347
        timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
348
        rv= s->parse_packet(s->ic, s->dynamic_protocol_context,
349
                            s->streams[s->prev_stream_id],
350
                            pkt, &timestamp, NULL, 0, flags);
351
        return rv;
352
    }
353

    
354
    if (len < 12)
355
        return -1;
356
    rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, &timestamp);
357
    if (rv < 0)
358
        return rv;
359
    if (is_keyframe &&
360
        (set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
361
         stream_id != s->prev_stream_id)) {
362
        flags |= RTP_FLAG_KEY;
363
        s->prev_set_id    = set_id;
364
        s->prev_timestamp = timestamp;
365
    }
366
    s->prev_stream_id = stream_id;
367
    buf += rv;
368
    len -= rv;
369

    
370
     if (s->prev_stream_id >= s->n_streams) {
371
         s->prev_stream_id = -1;
372
         return -1;
373
     }
374

    
375
    rv = s->parse_packet(s->ic, s->dynamic_protocol_context,
376
                         s->streams[s->prev_stream_id],
377
                         pkt, &timestamp, buf, len, flags);
378

    
379
    return rv;
380
}
381

    
382
void
383
ff_rdt_subscribe_rule (char *cmd, int size,
384
                       int stream_nr, int rule_nr)
385
{
386
    av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
387
                stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
388
}
389

    
390
static unsigned char *
391
rdt_parse_b64buf (unsigned int *target_len, const char *p)
392
{
393
    unsigned char *target;
394
    int len = strlen(p);
395
    if (*p == '\"') {
396
        p++;
397
        len -= 2; /* skip embracing " at start/end */
398
    }
399
    *target_len = len * 3 / 4;
400
    target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
401
    av_base64_decode(target, p, *target_len);
402
    return target;
403
}
404

    
405
static int
406
rdt_parse_sdp_line (AVFormatContext *s, int st_index,
407
                    PayloadContext *rdt, const char *line)
408
{
409
    AVStream *stream = s->streams[st_index];
410
    const char *p = line;
411

    
412
    if (av_strstart(p, "OpaqueData:buffer;", &p)) {
413
        rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
414
    } else if (av_strstart(p, "StartTime:integer;", &p))
415
        stream->first_dts = atoi(p);
416
    else if (av_strstart(p, "ASMRuleBook:string;", &p)) {
417
        int n, first = -1;
418

    
419
        for (n = 0; n < s->nb_streams; n++)
420
            if (s->streams[n]->id == stream->id) {
421
                int count = s->streams[n]->index + 1;
422
                if (first == -1) first = n;
423
                if (rdt->nb_rmst < count) {
424
                    RMStream **rmst= av_realloc(rdt->rmst, count*sizeof(*rmst));
425
                    if (!rmst)
426
                        return AVERROR(ENOMEM);
427
                    memset(rmst + rdt->nb_rmst, 0,
428
                           (count - rdt->nb_rmst) * sizeof(*rmst));
429
                    rdt->rmst    = rmst;
430
                    rdt->nb_rmst = count;
431
                }
432
                rdt->rmst[s->streams[n]->index] = ff_rm_alloc_rmstream();
433
                rdt_load_mdpr(rdt, s->streams[n], (n - first) * 2);
434

    
435
                if (s->streams[n]->codec->codec_id == CODEC_ID_AAC)
436
                    s->streams[n]->codec->frame_size = 1; // FIXME
437
           }
438
    }
439

    
440
    return 0;
441
}
442

    
443
static void
444
real_parse_asm_rule(AVStream *st, const char *p, const char *end)
445
{
446
    do {
447
        /* can be either averagebandwidth= or AverageBandwidth= */
448
        if (sscanf(p, " %*1[Aa]verage%*1[Bb]andwidth=%d", &st->codec->bit_rate) == 1)
449
            break;
450
        if (!(p = strchr(p, ',')) || p > end)
451
            p = end;
452
        p++;
453
    } while (p < end);
454
}
455

    
456
static AVStream *
457
add_dstream(AVFormatContext *s, AVStream *orig_st)
458
{
459
    AVStream *st;
460

    
461
    if (!(st = av_new_stream(s, orig_st->id)))
462
        return NULL;
463
    st->codec->codec_type = orig_st->codec->codec_type;
464
    st->first_dts         = orig_st->first_dts;
465

    
466
    return st;
467
}
468

    
469
static void
470
real_parse_asm_rulebook(AVFormatContext *s, AVStream *orig_st,
471
                        const char *p)
472
{
473
    const char *end;
474
    int n_rules = 0, odd = 0;
475
    AVStream *st;
476

    
477
    /**
478
     * The ASMRuleBook contains a list of comma-separated strings per rule,
479
     * and each rule is separated by a ;. The last one also has a ; at the
480
     * end so we can use it as delimiter.
481
     * Every rule occurs twice, once for when the RTSP packet header marker
482
     * is set and once for if it isn't. We only read the first because we
483
     * don't care much (that's what the "odd" variable is for).
484
     * Each rule contains a set of one or more statements, optionally
485
     * preceeded by a single condition. If there's a condition, the rule
486
     * starts with a '#'. Multiple conditions are merged between brackets,
487
     * so there are never multiple conditions spread out over separate
488
     * statements. Generally, these conditions are bitrate limits (min/max)
489
     * for multi-bitrate streams.
490
     */
491
    if (*p == '\"') p++;
492
    while (1) {
493
        if (!(end = strchr(p, ';')))
494
            break;
495
        if (!odd && end != p) {
496
            if (n_rules > 0)
497
                st = add_dstream(s, orig_st);
498
            else
499
                st = orig_st;
500
            if (!st)
501
                break;
502
            real_parse_asm_rule(st, p, end);
503
            n_rules++;
504
        }
505
        p = end + 1;
506
        odd ^= 1;
507
    }
508
}
509

    
510
void
511
ff_real_parse_sdp_a_line (AVFormatContext *s, int stream_index,
512
                          const char *line)
513
{
514
    const char *p = line;
515

    
516
    if (av_strstart(p, "ASMRuleBook:string;", &p))
517
        real_parse_asm_rulebook(s, s->streams[stream_index], p);
518
}
519

    
520
static PayloadContext *
521
rdt_new_context (void)
522
{
523
    PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
524

    
525
    av_open_input_stream(&rdt->rmctx, NULL, "", &ff_rdt_demuxer, NULL);
526

    
527
    return rdt;
528
}
529

    
530
static void
531
rdt_free_context (PayloadContext *rdt)
532
{
533
    int i;
534

    
535
    for (i = 0; i < rdt->nb_rmst; i++)
536
        if (rdt->rmst[i]) {
537
            ff_rm_free_rmstream(rdt->rmst[i]);
538
            av_freep(&rdt->rmst[i]);
539
        }
540
    if (rdt->rmctx)
541
        av_close_input_stream(rdt->rmctx);
542
    av_freep(&rdt->mlti_data);
543
    av_freep(&rdt->rmst);
544
    av_free(rdt);
545
}
546

    
547
#define RDT_HANDLER(n, s, t) \
548
static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
549
    .enc_name         = s, \
550
    .codec_type       = t, \
551
    .codec_id         = CODEC_ID_NONE, \
552
    .parse_sdp_a_line = rdt_parse_sdp_line, \
553
    .open             = rdt_new_context, \
554
    .close            = rdt_free_context, \
555
    .parse_packet     = rdt_parse_packet \
556
}
557

    
558
RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", AVMEDIA_TYPE_VIDEO);
559
RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", AVMEDIA_TYPE_AUDIO);
560
RDT_HANDLER(video,      "x-pn-realvideo",                AVMEDIA_TYPE_VIDEO);
561
RDT_HANDLER(audio,      "x-pn-realaudio",                AVMEDIA_TYPE_AUDIO);
562

    
563
void av_register_rdt_dynamic_payload_handlers(void)
564
{
565
    ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
566
    ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
567
    ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
568
    ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);
569
}