libavformat/rdt.c

   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 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 "rtp_internal.h"
  31 #include "rdt.h"
  32 #include "libavutil/base64.h"
  33 #include "libavutil/md5.h"
  34 #include "rm.h"
  35 #include "internal.h"
  36
  37 typedef struct rdt_data {
  38     AVFormatContext *rmctx;
  39     uint8_t *mlti_data;
  40     unsigned int mlti_data_size;
  41     uint32_t prev_sn, prev_ts;
  42     char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
  43 } rdt_data;
  44
  45 void
  46 ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
  47                                   const char *challenge)
  48 {
  49     int ch_len = strlen (challenge), i;
  50     unsigned char zres[16],
  51         buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
  52 #define XOR_TABLE_SIZE 37
  53     const unsigned char xor_table[XOR_TABLE_SIZE] = {
  54         0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
  55         0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
  56         0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
  57         0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
  58         0x10, 0x57, 0x05, 0x18, 0x54 };
  59
  60     /* some (length) checks */
  61     if (ch_len == 40) /* what a hack... */
  62         ch_len = 32;
  63     else if (ch_len > 56)
  64         ch_len = 56;
  65     memcpy(buf + 8, challenge, ch_len);
  66
  67     /* xor challenge bytewise with xor_table */
  68     for (i = 0; i < XOR_TABLE_SIZE; i++)
  69         buf[8 + i] ^= xor_table[i];
  70
  71     av_md5_sum(zres, buf, 64);
  72     ff_data_to_hex(response, zres, 16);
  73     for (i=0;i<32;i++) response[i] = tolower(response[i]);
  74
  75     /* add tail */
  76     strcpy (response + 32, "01d0a8e3");
  77
  78     /* calculate checksum */
  79     for (i = 0; i < 8; i++)
  80         chksum[i] = response[i * 4];
  81     chksum[8] = 0;
  82 }
  83
  84 static int
  85 rdt_load_mdpr (rdt_data *rdt, AVStream *st, int rule_nr)
  86 {
  87     ByteIOContext *pb;
  88     int size;
  89     uint32_t tag;
  90
  91     /**
  92      * Layout of the MLTI chunk:
  93      * 4:MLTI
  94      * 2:<number of streams>
  95      * Then for each stream ([number_of_streams] times):
  96      *     2:<mdpr index>
  97      * 2:<number of mdpr chunks>
  98      * Then for each mdpr chunk ([number_of_mdpr_chunks] times):
  99      *     4:<size>
 100      *     [size]:<data>
 101      * we skip MDPR chunks until we reach the one of the stream
 102      * we're interested in, and forward that ([size]+[data]) to
 103      * the RM demuxer to parse the stream-specific header data.
 104      */
 105     if (!rdt->mlti_data)
 106         return -1;
 107     url_open_buf(&pb, rdt->mlti_data, rdt->mlti_data_size, URL_RDONLY);
 108     tag = get_le32(pb);
 109     if (tag == MKTAG('M', 'L', 'T', 'I')) {
 110         int num, chunk_nr;
 111
 112         /* read index of MDPR chunk numbers */
 113         num = get_be16(pb);
 114         if (rule_nr < 0 || rule_nr >= num)
 115             return -1;
 116         url_fskip(pb, rule_nr * 2);
 117         chunk_nr = get_be16(pb);
 118         url_fskip(pb, (num - 1 - rule_nr) * 2);
 119
 120         /* read MDPR chunks */
 121         num = get_be16(pb);
 122         if (chunk_nr >= num)
 123             return -1;
 124         while (chunk_nr--)
 125             url_fskip(pb, get_be32(pb));
 126         size = get_be32(pb);
 127     } else {
 128         size = rdt->mlti_data_size;
 129         url_fseek(pb, 0, SEEK_SET);
 130     }
 131     rdt->rmctx->pb = pb;
 132     if (ff_rm_read_mdpr_codecdata(rdt->rmctx, st, size) < 0)
 133         return -1;
 134
 135     url_close_buf(pb);
 136     return 0;
 137 }
 138
 139 /**
 140  * Actual data handling.
 141  */
 142
 143 static int rdt_parse_header(struct RTPDemuxContext *s, const uint8_t *buf,
 144                             int len, int *seq, uint32_t *timestamp, int *flags)
 145 {
 146     rdt_data *rdt = s->dynamic_protocol_context;
 147     int consumed = 0, sn;
 148
 149     if (buf[0] < 0x40 || buf[0] > 0x42) {
 150         buf += 9;
 151         len -= 9;
 152         consumed += 9;
 153     }
 154     sn = (buf[0]>>1) & 0x1f;
 155     *seq = AV_RB16(buf+1);
 156     *timestamp = AV_RB32(buf+4);
 157     if (!(buf[3] & 1) && (sn != rdt->prev_sn || *timestamp != rdt->prev_ts)) {
 158         *flags |= PKT_FLAG_KEY;
 159         rdt->prev_sn = sn;
 160         rdt->prev_ts = *timestamp;
 161     }
 162
 163     return consumed + 10;
 164 }
 165
 166 /**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
 167 static int
 168 rdt_parse_packet (RTPDemuxContext *s, AVPacket *pkt, uint32_t *timestamp,
 169                   const uint8_t *buf, int len, int flags)
 170 {
 171     rdt_data *rdt = s->dynamic_protocol_context;
 172     int seq = 1, res;
 173     ByteIOContext *pb = rdt->rmctx->pb;
 174     RMContext *rm = rdt->rmctx->priv_data;
 175     AVStream *st = s->st;
 176
 177     if (rm->audio_pkt_cnt == 0) {
 178         int pos;
 179
 180         url_open_buf (&pb, buf, len, URL_RDONLY);
 181         flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
 182         rdt->rmctx->pb = pb;
 183         res = ff_rm_parse_packet (rdt->rmctx, st, len, pkt,
 184                                   &seq, &flags, timestamp);
 185         pos = url_ftell(pb);
 186         url_close_buf (pb);
 187         if (res < 0)
 188             return res;
 189         if (rm->audio_pkt_cnt > 0 &&
 190             st->codec->codec_id == CODEC_ID_AAC) {
 191             memcpy (rdt->buffer, buf + pos, len - pos);
 192             url_open_buf (&pb, rdt->buffer, len - pos, URL_RDONLY);
 193             rdt->rmctx->pb = pb;
 194         }
 195     } else {
 196         ff_rm_retrieve_cache (rdt->rmctx, st, pkt);
 197         if (rm->audio_pkt_cnt == 0 &&
 198             st->codec->codec_id == CODEC_ID_AAC)
 199             url_close_buf (pb);
 200     }
 201     pkt->stream_index = st->index;
 202     pkt->pts = *timestamp;
 203
 204     return rm->audio_pkt_cnt > 0;
 205 }
 206
 207 int
 208 ff_rdt_parse_packet(RTPDemuxContext *s, AVPacket *pkt,
 209                     const uint8_t *buf, int len)
 210 {
 211     int seq, flags = 0;
 212     uint32_t timestamp;
 213     int rv= 0;
 214
 215     if (!buf) {
 216         /* return the next packets, if any */
 217         timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
 218         rv= rdt_parse_packet(s, pkt, &timestamp, NULL, 0, flags);
 219         return rv;
 220     }
 221
 222     if (len < 12)
 223         return -1;
 224     rv = rdt_parse_header(s, buf, len, &seq, &timestamp, &flags);
 225     if (rv < 0)
 226         return rv;
 227     buf += rv;
 228     len -= rv;
 229     s->seq = seq;
 230
 231     rv = rdt_parse_packet(s, pkt, &timestamp, buf, len, flags);
 232
 233     return rv;
 234 }
 235
 236 void
 237 ff_rdt_subscribe_rule (RTPDemuxContext *s, char *cmd, int size,
 238                        int stream_nr, int rule_nr)
 239 {
 240     rdt_data *rdt = s->dynamic_protocol_context;
 241
 242     av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
 243                 stream_nr, rule_nr, stream_nr, rule_nr + 1);
 244
 245     rdt_load_mdpr(rdt, s->st, 0);
 246 }
 247
 248 static unsigned char *
 249 rdt_parse_b64buf (unsigned int *target_len, const char *p)
 250 {
 251     unsigned char *target;
 252     int len = strlen(p);
 253     if (*p == '\"') {
 254         p++;
 255         len -= 2; /* skip embracing " at start/end */
 256     }
 257     *target_len = len * 3 / 4;
 258     target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
 259     av_base64_decode(target, p, *target_len);
 260     return target;
 261 }
 262
 263 static int
 264 rdt_parse_sdp_line (AVStream *stream, void *d, const char *line)
 265 {
 266     rdt_data *rdt = d;
 267     const char *p = line;
 268
 269     if (av_strstart(p, "OpaqueData:buffer;", &p)) {
 270         rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
 271     } else if (av_strstart(p, "StartTime:integer;", &p))
 272         stream->first_dts = atoi(p);
 273
 274     return 0;
 275 }
 276
 277 static void *
 278 rdt_new_extradata (void)
 279 {
 280     rdt_data *rdt = av_mallocz(sizeof(rdt_data));
 281
 282     av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
 283     rdt->prev_ts = -1;
 284     rdt->prev_sn = -1;
 285
 286     return rdt;
 287 }
 288
 289 static void
 290 rdt_free_extradata (void *d)
 291 {
 292     rdt_data *rdt = d;
 293
 294     if (rdt->rmctx)
 295         av_close_input_stream(rdt->rmctx);
 296     av_freep(&rdt->mlti_data);
 297     av_free(rdt);
 298 }
 299
 300 #define RDT_HANDLER(n, s, t) \
 301 static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
 302     s, \
 303     t, \
 304     CODEC_ID_NONE, \
 305     rdt_parse_sdp_line, \
 306     rdt_new_extradata, \
 307     rdt_free_extradata \
 308 };
 309
 310 RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
 311 RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
 312 RDT_HANDLER(video,      "x-pn-realvideo",                CODEC_TYPE_VIDEO);
 313 RDT_HANDLER(audio,      "x-pn-realaudio",                CODEC_TYPE_AUDIO);
 314
 315 void av_register_rdt_dynamic_payload_handlers(void)
 316 {
 317     ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
 318     ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
 319     ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
 320     ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);
 321 }