git.sesse.net Git - ffmpeg/blob - libavformat/mmst.c

   1 /*
   2  * MMS protocol over TCP
   3  * Copyright (c) 2006,2007 Ryan Martell
   4  * Copyright (c) 2007 Björn Axelsson
   5  * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /* References
  25  * MMS protocol specification:
  26  *  [1]http://msdn.microsoft.com/en-us/library/cc234711(PROT.10).aspx
  27  * ASF specification. Revision 01.20.03.
  28  *  [2]http://msdn.microsoft.com/en-us/library/bb643323.aspx
  29  */
  30
  31 #include "avformat.h"
  32 #include "mms.h"
  33 #include "internal.h"
  34 #include "libavutil/intreadwrite.h"
  35 #include "libavcodec/bytestream.h"
  36 #include "network.h"
  37
  38 #define LOCAL_ADDRESS 0xc0a80081    // FIXME get and use correct local ip address.
  39 #define LOCAL_PORT    1037          // as above.
  40 /** Client to server packet types. */
  41 typedef enum {
  42     CS_PKT_INITIAL                  = 0x01,
  43     CS_PKT_PROTOCOL_SELECT          = 0x02,
  44     CS_PKT_MEDIA_FILE_REQUEST       = 0x05,
  45     CS_PKT_START_FROM_PKT_ID        = 0x07,
  46     CS_PKT_STREAM_PAUSE             = 0x09,
  47     CS_PKT_STREAM_CLOSE             = 0x0d,
  48     CS_PKT_MEDIA_HEADER_REQUEST     = 0x15,
  49     CS_PKT_TIMING_DATA_REQUEST      = 0x18,
  50     CS_PKT_USER_PASSWORD            = 0x1a,
  51     CS_PKT_KEEPALIVE                = 0x1b,
  52     CS_PKT_STREAM_ID_REQUEST        = 0x33,
  53 } MMSCSPacketType;
  54
  55 /** Server to client packet types. */
  56 typedef enum {
  57     /** Control packets. */
  58     /*@{*/
  59     SC_PKT_CLIENT_ACCEPTED          = 0x01,
  60     SC_PKT_PROTOCOL_ACCEPTED        = 0x02,
  61     SC_PKT_PROTOCOL_FAILED          = 0x03,
  62     SC_PKT_MEDIA_PKT_FOLLOWS        = 0x05,
  63     SC_PKT_MEDIA_FILE_DETAILS       = 0x06,
  64     SC_PKT_HEADER_REQUEST_ACCEPTED  = 0x11,
  65     SC_PKT_TIMING_TEST_REPLY        = 0x15,
  66     SC_PKT_PASSWORD_REQUIRED        = 0x1a,
  67     SC_PKT_KEEPALIVE                = 0x1b,
  68     SC_PKT_STREAM_STOPPED           = 0x1e,
  69     SC_PKT_STREAM_CHANGING          = 0x20,
  70     SC_PKT_STREAM_ID_ACCEPTED       = 0x21,
  71     /*@}*/
  72
  73     /** Pseudo packets. */
  74     /*@{*/
  75     SC_PKT_CANCEL                   = -1,
  76     SC_PKT_NO_DATA                  = -2,
  77     /*@}*/
  78
  79     /** Data packets. */
  80     /*@{*/
  81     SC_PKT_ASF_HEADER               = 0x010000,// make it bigger than 0xFF in case of
  82     SC_PKT_ASF_MEDIA                = 0x010001,// receiving false data packets.
  83     /*@}*/
  84 } MMSSCPacketType;
  85
  86 typedef struct {
  87     MMSContext  mms;
  88     int outgoing_packet_seq;             ///< Outgoing packet sequence number.
  89     char path[256];                      ///< Path of the resource being asked for.
  90     char host[128];                      ///< Host of the resources.
  91     int incoming_packet_seq;             ///< Incoming packet sequence number.
  92     int incoming_flags;                  ///< Incoming packet flags.
  93     int packet_id;                       ///< Identifier for packets in the current stream.
  94     unsigned int header_packet_id;       ///< default is 2.
  95 } MMSTContext;
  96
  97 /** Create MMST command packet header */
  98 static void start_command_packet(MMSTContext *mmst, MMSCSPacketType packet_type)
  99 {
 100     MMSContext *mms    = &mmst->mms;
 101     mms->write_out_ptr = mms->out_buffer;
 102
 103     bytestream_put_le32(&mms->write_out_ptr, 1); // start sequence
 104     bytestream_put_le32(&mms->write_out_ptr, 0xb00bface);
 105     bytestream_put_le32(&mms->write_out_ptr, 0); // Length starts from after the protocol type bytes
 106     bytestream_put_le32(&mms->write_out_ptr, MKTAG('M','M','S',' '));
 107     bytestream_put_le32(&mms->write_out_ptr, 0);
 108     bytestream_put_le32(&mms->write_out_ptr, mmst->outgoing_packet_seq++);
 109     bytestream_put_le64(&mms->write_out_ptr, 0); // timestamp
 110     bytestream_put_le32(&mms->write_out_ptr, 0);
 111     bytestream_put_le16(&mms->write_out_ptr, packet_type);
 112     bytestream_put_le16(&mms->write_out_ptr, 3); // direction to server
 113 }
 114
 115 /** Add prefixes to MMST command packet. */
 116 static void insert_command_prefixes(MMSContext *mms,
 117         uint32_t prefix1, uint32_t prefix2)
 118 {
 119     bytestream_put_le32(&mms->write_out_ptr, prefix1); // first prefix
 120     bytestream_put_le32(&mms->write_out_ptr, prefix2); // second prefix
 121 }
 122
 123 /** Send a prepared MMST command packet. */
 124 static int send_command_packet(MMSTContext *mmst)
 125 {
 126     MMSContext *mms  = &mmst->mms;
 127     int len= mms->write_out_ptr - mms->out_buffer;
 128     int exact_length = FFALIGN(len, 8);
 129     int first_length= exact_length - 16;
 130     int len8= first_length/8;
 131     int write_result;
 132
 133     // update packet length fields.
 134     AV_WL32(mms->out_buffer + 8, first_length);
 135     AV_WL32(mms->out_buffer + 16, len8);
 136     AV_WL32(mms->out_buffer + 32, len8-2);
 137     memset(mms->write_out_ptr, 0, exact_length - len);
 138
 139     // write it out.
 140     write_result= url_write(mms->mms_hd, mms->out_buffer, exact_length);
 141     if(write_result != exact_length) {
 142         av_log(NULL, AV_LOG_ERROR,
 143                "Failed to write data of length %d: %d (%s)\n",
 144                exact_length, write_result,
 145                write_result < 0 ? strerror(write_result) :
 146                    "The server closed the connection");
 147         return AVERROR_IO;
 148     }
 149
 150     return 0;
 151 }
 152
 153 static void mms_put_utf16(MMSContext *mms, uint8_t *src)
 154 {
 155     ByteIOContext bic;
 156     int size = mms->write_out_ptr - mms->out_buffer;
 157     int len;
 158     init_put_byte(&bic, mms->write_out_ptr,
 159             sizeof(mms->out_buffer) - size, 1, NULL, NULL, NULL, NULL);
 160
 161     len = avio_put_str16le(&bic, src);
 162     mms->write_out_ptr += len;
 163 }
 164
 165 static int send_time_test_data(MMSTContext *mmst)
 166 {
 167     start_command_packet(mmst, CS_PKT_TIMING_DATA_REQUEST);
 168     insert_command_prefixes(&mmst->mms, 0x00f0f0f0, 0x0004000b);
 169     return send_command_packet(mmst);
 170 }
 171
 172 static int send_protocol_select(MMSTContext *mmst)
 173 {
 174     char data_string[256];
 175     MMSContext *mms = &mmst->mms;
 176
 177     start_command_packet(mmst, CS_PKT_PROTOCOL_SELECT);
 178     insert_command_prefixes(mms, 0, 0xffffffff);
 179     bytestream_put_le32(&mms->write_out_ptr, 0);          // maxFunnelBytes
 180     bytestream_put_le32(&mms->write_out_ptr, 0x00989680); // maxbitRate
 181     bytestream_put_le32(&mms->write_out_ptr, 2);          // funnelMode
 182     snprintf(data_string, sizeof(data_string), "\\\\%d.%d.%d.%d\\%s\\%d",
 183             (LOCAL_ADDRESS>>24)&0xff,
 184             (LOCAL_ADDRESS>>16)&0xff,
 185             (LOCAL_ADDRESS>>8)&0xff,
 186             LOCAL_ADDRESS&0xff,
 187             "TCP",                                        // or UDP
 188             LOCAL_PORT);
 189
 190     mms_put_utf16(mms, data_string);
 191     return send_command_packet(mmst);
 192 }
 193
 194 static int send_media_file_request(MMSTContext *mmst)
 195 {
 196     MMSContext *mms = &mmst->mms;
 197     start_command_packet(mmst, CS_PKT_MEDIA_FILE_REQUEST);
 198     insert_command_prefixes(mms, 1, 0xffffffff);
 199     bytestream_put_le32(&mms->write_out_ptr, 0);
 200     bytestream_put_le32(&mms->write_out_ptr, 0);
 201     mms_put_utf16(mms, mmst->path + 1); // +1 for skip "/"
 202
 203     return send_command_packet(mmst);
 204 }
 205
 206 static void handle_packet_stream_changing_type(MMSTContext *mmst)
 207 {
 208     MMSContext *mms = &mmst->mms;
 209     av_dlog(NULL, "Stream changing!\n");
 210
 211     // 40 is the packet header size, 7 is the prefix size.
 212     mmst->header_packet_id= AV_RL32(mms->in_buffer + 40 + 7);
 213     av_dlog(NULL, "Changed header prefix to 0x%x", mmst->header_packet_id);
 214 }
 215
 216 static int send_keepalive_packet(MMSTContext *mmst)
 217 {
 218     // respond to a keepalive with a keepalive...
 219     start_command_packet(mmst, CS_PKT_KEEPALIVE);
 220     insert_command_prefixes(&mmst->mms, 1, 0x100FFFF);
 221     return send_command_packet(mmst);
 222 }
 223
 224 /** Pad media packets smaller than max_packet_size and/or adjust read position
 225   * after a seek. */
 226 static void pad_media_packet(MMSContext *mms)
 227 {
 228     if(mms->remaining_in_len<mms->asf_packet_len) {
 229         int padding_size = mms->asf_packet_len - mms->remaining_in_len;
 230         memset(mms->in_buffer + mms->remaining_in_len, 0, padding_size);
 231         mms->remaining_in_len += padding_size;
 232     }
 233 }
 234
 235 /** Read incoming MMST media, header or command packet. */
 236 static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
 237 {
 238     int read_result;
 239     MMSSCPacketType packet_type= -1;
 240     MMSContext *mms = &mmst->mms;
 241     for(;;) {
 242         read_result = url_read_complete(mms->mms_hd, mms->in_buffer, 8);
 243         if (read_result != 8) {
 244             if(read_result < 0) {
 245                 av_log(NULL, AV_LOG_ERROR,
 246                        "Error reading packet header: %d (%s)\n",
 247                        read_result, strerror(read_result));
 248                 packet_type = SC_PKT_CANCEL;
 249             } else {
 250                 av_log(NULL, AV_LOG_ERROR,
 251                        "The server closed the connection\n");
 252                 packet_type = SC_PKT_NO_DATA;
 253             }
 254             return packet_type;
 255         }
 256
 257         // handle command packet.
 258         if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {
 259             int length_remaining, hr;
 260
 261             mmst->incoming_flags= mms->in_buffer[3];
 262             read_result= url_read_complete(mms->mms_hd, mms->in_buffer+8, 4);
 263             if(read_result != 4) {
 264                 av_log(NULL, AV_LOG_ERROR,
 265                        "Reading command packet length failed: %d (%s)\n",
 266                        read_result,
 267                        read_result < 0 ? strerror(read_result) :
 268                            "The server closed the connection");
 269                 return read_result < 0 ? read_result : AVERROR_IO;
 270             }
 271
 272             length_remaining= AV_RL32(mms->in_buffer+8) + 4;
 273             av_dlog(NULL, "Length remaining is %d\n", length_remaining);
 274             // read the rest of the packet.
 275             if (length_remaining < 0
 276                 || length_remaining > sizeof(mms->in_buffer) - 12) {
 277                 av_log(NULL, AV_LOG_ERROR,
 278                        "Incoming packet length %d exceeds bufsize %zu\n",
 279                        length_remaining, sizeof(mms->in_buffer) - 12);
 280                 return AVERROR_INVALIDDATA;
 281             }
 282             read_result = url_read_complete(mms->mms_hd, mms->in_buffer + 12,
 283                                             length_remaining) ;
 284             if (read_result != length_remaining) {
 285                 av_log(NULL, AV_LOG_ERROR,
 286                        "Reading pkt data (length=%d) failed: %d (%s)\n",
 287                        length_remaining, read_result,
 288                        read_result < 0 ? strerror(read_result) :
 289                            "The server closed the connection");
 290                 return read_result < 0 ? read_result : AVERROR_IO;
 291             }
 292             packet_type= AV_RL16(mms->in_buffer+36);
 293             hr = AV_RL32(mms->in_buffer + 40);
 294             if (hr) {
 295                 av_log(NULL, AV_LOG_ERROR,
 296                        "Server sent an error status code: 0x%08x\n", hr);
 297                 return AVERROR_UNKNOWN;
 298             }
 299         } else {
 300             int length_remaining;
 301             int packet_id_type;
 302             int tmp;
 303
 304             // note we cache the first 8 bytes,
 305             // then fill up the buffer with the others
 306             tmp                       = AV_RL16(mms->in_buffer + 6);
 307             length_remaining          = (tmp - 8) & 0xffff;
 308             mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);
 309             packet_id_type            = mms->in_buffer[4];
 310             mmst->incoming_flags      = mms->in_buffer[5];
 311
 312             if (length_remaining < 0
 313                 || length_remaining > sizeof(mms->in_buffer) - 8) {
 314                 av_log(NULL, AV_LOG_ERROR,
 315                        "Data length %d is invalid or too large (max=%zu)\n",
 316                        length_remaining, sizeof(mms->in_buffer));
 317                 return AVERROR_INVALIDDATA;
 318             }
 319             mms->remaining_in_len    = length_remaining;
 320             mms->read_in_ptr         = mms->in_buffer;
 321             read_result= url_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
 322             if(read_result != length_remaining) {
 323                 av_log(NULL, AV_LOG_ERROR,
 324                        "Failed to read packet data of size %d: %d (%s)\n",
 325                        length_remaining, read_result,
 326                        read_result < 0 ? strerror(read_result) :
 327                            "The server closed the connection");
 328                 return read_result < 0 ? read_result : AVERROR_IO;
 329             }
 330
 331             // if we successfully read everything.
 332             if(packet_id_type == mmst->header_packet_id) {
 333                 packet_type = SC_PKT_ASF_HEADER;
 334                 // Store the asf header
 335                 if(!mms->header_parsed) {
 336                     void *p = av_realloc(mms->asf_header,
 337                                   mms->asf_header_size + mms->remaining_in_len);
 338                     if (!p) {
 339                         av_freep(&mms->asf_header);
 340                         return AVERROR(ENOMEM);
 341                     }
 342                     mms->asf_header = p;
 343                     memcpy(mms->asf_header + mms->asf_header_size,
 344                            mms->read_in_ptr, mms->remaining_in_len);
 345                     mms->asf_header_size += mms->remaining_in_len;
 346                 }
 347                 // 0x04 means asf header is sent in multiple packets.
 348                 if (mmst->incoming_flags == 0x04)
 349                     continue;
 350             } else if(packet_id_type == mmst->packet_id) {
 351                 packet_type = SC_PKT_ASF_MEDIA;
 352             } else {
 353                 av_dlog(NULL, "packet id type %d is old.", packet_id_type);
 354                 continue;
 355             }
 356         }
 357
 358         // preprocess some packet type
 359         if(packet_type == SC_PKT_KEEPALIVE) {
 360             send_keepalive_packet(mmst);
 361             continue;
 362         } else if(packet_type == SC_PKT_STREAM_CHANGING) {
 363             handle_packet_stream_changing_type(mmst);
 364         } else if(packet_type == SC_PKT_ASF_MEDIA) {
 365             pad_media_packet(mms);
 366         }
 367         return packet_type;
 368     }
 369 }
 370
 371 static int mms_safe_send_recv(MMSTContext *mmst,
 372                               int (*send_fun)(MMSTContext *mmst),
 373                               const MMSSCPacketType expect_type)
 374 {
 375     MMSSCPacketType type;
 376     if(send_fun) {
 377         int ret = send_fun(mmst);
 378         if (ret < 0) {
 379             av_dlog(NULL, "Send Packet error before expecting recv packet %d\n", expect_type);
 380             return ret;
 381         }
 382     }
 383
 384     if ((type = get_tcp_server_response(mmst)) != expect_type) {
 385         av_log(NULL, AV_LOG_ERROR,
 386                "Corrupt stream (unexpected packet type 0x%x, expected 0x%x)\n",
 387                type, expect_type);
 388         return AVERROR_INVALIDDATA;
 389     } else {
 390         return 0;
 391     }
 392 }
 393
 394 static int send_media_header_request(MMSTContext *mmst)
 395 {
 396     MMSContext *mms = &mmst->mms;
 397     start_command_packet(mmst, CS_PKT_MEDIA_HEADER_REQUEST);
 398     insert_command_prefixes(mms, 1, 0);
 399     bytestream_put_le32(&mms->write_out_ptr, 0);
 400     bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
 401     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
 402     bytestream_put_le32(&mms->write_out_ptr, 0);
 403     bytestream_put_le32(&mms->write_out_ptr, 0);
 404     bytestream_put_le32(&mms->write_out_ptr, 0);
 405
 406     // the media preroll value in milliseconds?
 407     bytestream_put_le32(&mms->write_out_ptr, 0);
 408     bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
 409     bytestream_put_le32(&mms->write_out_ptr, 2);
 410     bytestream_put_le32(&mms->write_out_ptr, 0);
 411
 412     return send_command_packet(mmst);
 413 }
 414
 415 /** Send the initial handshake. */
 416 static int send_startup_packet(MMSTContext *mmst)
 417 {
 418     char data_string[256];
 419     MMSContext *mms = &mmst->mms;
 420     // SubscriberName is defined in MS specification linked below.
 421     // The guid value can be any valid value.
 422     // http://download.microsoft.com/
 423     // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
 424     snprintf(data_string, sizeof(data_string),
 425             "NSPlayer/7.0.0.1956; {%s}; Host: %s",
 426             "7E667F5D-A661-495E-A512-F55686DDA178", mmst->host);
 427
 428     start_command_packet(mmst, CS_PKT_INITIAL);
 429     insert_command_prefixes(mms, 0, 0x0004000b);
 430     bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
 431     mms_put_utf16(mms, data_string);
 432     return send_command_packet(mmst);
 433 }
 434
 435 /** Send MMST stream selection command based on the AVStream->discard values. */
 436 static int send_stream_selection_request(MMSTContext *mmst)
 437 {
 438     int i;
 439     MMSContext *mms = &mmst->mms;
 440     //  send the streams we want back...
 441     start_command_packet(mmst, CS_PKT_STREAM_ID_REQUEST);
 442     bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
 443     for(i= 0; i<mms->stream_num; i++) {
 444         bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
 445         bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
 446         bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
 447     }
 448     return send_command_packet(mmst);
 449 }
 450
 451 static int send_close_packet(MMSTContext *mmst)
 452 {
 453     start_command_packet(mmst, CS_PKT_STREAM_CLOSE);
 454     insert_command_prefixes(&mmst->mms, 1, 1);
 455
 456     return send_command_packet(mmst);
 457 }
 458
 459 /** Close the MMSH/MMST connection */
 460 static int mms_close(URLContext *h)
 461 {
 462     MMSTContext *mmst = (MMSTContext *)h->priv_data;
 463     MMSContext *mms   = &mmst->mms;
 464     if(mms->mms_hd) {
 465         send_close_packet(mmst);
 466         url_close(mms->mms_hd);
 467     }
 468
 469     /* free all separately allocated pointers in mms */
 470     av_free(mms->streams);
 471     av_free(mms->asf_header);
 472     av_freep(&h->priv_data);
 473
 474     return 0;
 475 }
 476
 477 static int send_media_packet_request(MMSTContext *mmst)
 478 {
 479     MMSContext *mms = &mmst->mms;
 480     start_command_packet(mmst, CS_PKT_START_FROM_PKT_ID);
 481     insert_command_prefixes(mms, 1, 0x0001FFFF);
 482     bytestream_put_le64(&mms->write_out_ptr, 0);          // seek timestamp
 483     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // unknown
 484     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // packet offset
 485     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
 486     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
 487     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
 488     bytestream_put_byte(&mms->write_out_ptr, 0x00);       // stream time limit flag
 489
 490     mmst->packet_id++;                                     // new packet_id
 491     bytestream_put_le32(&mms->write_out_ptr, mmst->packet_id);
 492     return send_command_packet(mmst);
 493 }
 494
 495
 496 static void clear_stream_buffers(MMSContext *mms)
 497 {
 498     mms->remaining_in_len = 0;
 499     mms->read_in_ptr      = mms->in_buffer;
 500 }
 501
 502 static int mms_open(URLContext *h, const char *uri, int flags)
 503 {
 504     MMSTContext *mmst;
 505     MMSContext *mms;
 506     int port, err;
 507     char tcpname[256];
 508
 509     h->is_streamed = 1;
 510     mmst = h->priv_data = av_mallocz(sizeof(MMSTContext));
 511     if (!h->priv_data)
 512         return AVERROR(ENOMEM);
 513     mms = &mmst->mms;
 514
 515     // only for MMS over TCP, so set proto = NULL
 516     av_url_split(NULL, 0, NULL, 0,
 517             mmst->host, sizeof(mmst->host), &port, mmst->path,
 518             sizeof(mmst->path), uri);
 519
 520     if(port<0)
 521         port = 1755; // defaut mms protocol port
 522
 523     // establish tcp connection.
 524     ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mmst->host, port, NULL);
 525     err = url_open(&mms->mms_hd, tcpname, URL_RDWR);
 526     if (err)
 527         goto fail;
 528
 529     mmst->packet_id        = 3;          // default, initial value.
 530     mmst->header_packet_id = 2;          // default, initial value.
 531     err = mms_safe_send_recv(mmst, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);
 532     if (err)
 533         goto fail;
 534     err = mms_safe_send_recv(mmst, send_time_test_data, SC_PKT_TIMING_TEST_REPLY);
 535     if (err)
 536         goto fail;
 537     err = mms_safe_send_recv(mmst, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);
 538     if (err)
 539         goto fail;
 540     err = mms_safe_send_recv(mmst, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);
 541     if (err)
 542         goto fail;
 543     err = mms_safe_send_recv(mmst, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);
 544     if (err)
 545         goto fail;
 546     err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_HEADER);
 547     if (err)
 548         goto fail;
 549     if((mmst->incoming_flags != 0X08) && (mmst->incoming_flags != 0X0C)) {
 550         av_log(NULL, AV_LOG_ERROR,
 551                "The server does not support MMST (try MMSH or RTSP)\n");
 552         err = AVERROR_NOFMT;
 553         goto fail;
 554     }
 555     err = ff_mms_asf_header_parser(mms);
 556     if (err) {
 557         av_dlog(NULL, "asf header parsed failed!\n");
 558         goto fail;
 559     }
 560     mms->header_parsed = 1;
 561
 562     if (!mms->asf_packet_len || !mms->stream_num)
 563         goto fail;
 564
 565     clear_stream_buffers(mms);
 566     err = mms_safe_send_recv(mmst, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);
 567     if (err)
 568         goto fail;
 569     // send media packet request
 570     err = mms_safe_send_recv(mmst, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);
 571     if (err) {
 572         goto fail;
 573     }
 574     av_dlog(NULL, "Leaving open (success)\n");
 575     return 0;
 576 fail:
 577     mms_close(h);
 578     av_dlog(NULL, "Leaving open (failure: %d)\n", err);
 579     return err;
 580 }
 581
 582 /** Read ASF data through the protocol. */
 583 static int mms_read(URLContext *h, uint8_t *buf, int size)
 584 {
 585     /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */
 586     MMSTContext *mmst = h->priv_data;
 587     MMSContext *mms   = &mmst->mms;
 588     int result = 0;
 589
 590     do {
 591         if(mms->asf_header_read_size < mms->asf_header_size) {
 592             /* Read from ASF header buffer */
 593             result = ff_mms_read_header(mms, buf, size);
 594         } else if(mms->remaining_in_len) {
 595             /* Read remaining packet data to buffer.
 596              * the result can not be zero because remaining_in_len is positive.*/
 597             result = ff_mms_read_data(mms, buf, size);
 598         } else {
 599             /* Read from network */
 600             int err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_MEDIA);
 601             if (err == 0) {
 602                 if(mms->remaining_in_len>mms->asf_packet_len) {
 603                     av_log(NULL, AV_LOG_ERROR,
 604                            "Incoming pktlen %d is larger than ASF pktsize %d\n",
 605                            mms->remaining_in_len, mms->asf_packet_len);
 606                     result= AVERROR_IO;
 607                 } else {
 608                     // copy the data to the packet buffer.
 609                     result = ff_mms_read_data(mms, buf, size);
 610                     if (result == 0) {
 611                         av_dlog(NULL, "read asf media paket size is zero!\n");
 612                         break;
 613                     }
 614                 }
 615             } else {
 616                 av_dlog(NULL, "read packet error!\n");
 617                 break;
 618             }
 619         }
 620     } while(!result); // only return one packet.
 621     return result;
 622 }
 623
 624 URLProtocol ff_mmst_protocol = {
 625     "mmst",
 626     mms_open,
 627     mms_read,
 628     NULL, // write
 629     NULL, // seek
 630     mms_close,
 631 };