Merge commit 'd872fb0f7ff2ff0ba87f5ccf6a1a55ca2be472c9'
[ffmpeg.git] / libavformat / mmst.c
1 /*
2  * MMS protocol over TCP
3  * Copyright (c) 2006,2007 Ryan Martell
4  * Copyright (c) 2007 Bj√∂rn 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 "avio_internal.h"
35 #include "libavutil/intreadwrite.h"
36 #include "libavcodec/bytestream.h"
37 #include "network.h"
38 #include "url.h"
39
40 #define LOCAL_ADDRESS 0xc0a80081    // FIXME get and use correct local ip address.
41 #define LOCAL_PORT    1037          // as above.
42 /** Client to server packet types. */
43 typedef enum {
44     CS_PKT_INITIAL                  = 0x01,
45     CS_PKT_PROTOCOL_SELECT          = 0x02,
46     CS_PKT_MEDIA_FILE_REQUEST       = 0x05,
47     CS_PKT_START_FROM_PKT_ID        = 0x07,
48     CS_PKT_STREAM_PAUSE             = 0x09,
49     CS_PKT_STREAM_CLOSE             = 0x0d,
50     CS_PKT_MEDIA_HEADER_REQUEST     = 0x15,
51     CS_PKT_TIMING_DATA_REQUEST      = 0x18,
52     CS_PKT_USER_PASSWORD            = 0x1a,
53     CS_PKT_KEEPALIVE                = 0x1b,
54     CS_PKT_STREAM_ID_REQUEST        = 0x33,
55 } MMSCSPacketType;
56
57 /** Server to client packet types. */
58 typedef enum {
59     /** Control packets. */
60     /*@{*/
61     SC_PKT_CLIENT_ACCEPTED          = 0x01,
62     SC_PKT_PROTOCOL_ACCEPTED        = 0x02,
63     SC_PKT_PROTOCOL_FAILED          = 0x03,
64     SC_PKT_MEDIA_PKT_FOLLOWS        = 0x05,
65     SC_PKT_MEDIA_FILE_DETAILS       = 0x06,
66     SC_PKT_HEADER_REQUEST_ACCEPTED  = 0x11,
67     SC_PKT_TIMING_TEST_REPLY        = 0x15,
68     SC_PKT_PASSWORD_REQUIRED        = 0x1a,
69     SC_PKT_KEEPALIVE                = 0x1b,
70     SC_PKT_STREAM_STOPPED           = 0x1e,
71     SC_PKT_STREAM_CHANGING          = 0x20,
72     SC_PKT_STREAM_ID_ACCEPTED       = 0x21,
73     /*@}*/
74
75     /** Pseudo packets. */
76     /*@{*/
77     SC_PKT_CANCEL                   = -1,
78     SC_PKT_NO_DATA                  = -2,
79     /*@}*/
80
81     /** Data packets. */
82     /*@{*/
83     SC_PKT_ASF_HEADER               = 0x010000,// make it bigger than 0xFF in case of
84     SC_PKT_ASF_MEDIA                = 0x010001,// receiving false data packets.
85     /*@}*/
86 } MMSSCPacketType;
87
88 typedef struct {
89     MMSContext  mms;
90     int outgoing_packet_seq;             ///< Outgoing packet sequence number.
91     char path[256];                      ///< Path of the resource being asked for.
92     char host[128];                      ///< Host of the resources.
93     int incoming_packet_seq;             ///< Incoming packet sequence number.
94     int incoming_flags;                  ///< Incoming packet flags.
95     int packet_id;                       ///< Identifier for packets in the current stream.
96     unsigned int header_packet_id;       ///< default is 2.
97 } MMSTContext;
98
99 /** Create MMST command packet header */
100 static void start_command_packet(MMSTContext *mmst, MMSCSPacketType packet_type)
101 {
102     MMSContext *mms    = &mmst->mms;
103     mms->write_out_ptr = mms->out_buffer;
104
105     bytestream_put_le32(&mms->write_out_ptr, 1); // start sequence
106     bytestream_put_le32(&mms->write_out_ptr, 0xb00bface);
107     bytestream_put_le32(&mms->write_out_ptr, 0); // Length starts from after the protocol type bytes
108     bytestream_put_le32(&mms->write_out_ptr, MKTAG('M','M','S',' '));
109     bytestream_put_le32(&mms->write_out_ptr, 0);
110     bytestream_put_le32(&mms->write_out_ptr, mmst->outgoing_packet_seq++);
111     bytestream_put_le64(&mms->write_out_ptr, 0); // timestamp
112     bytestream_put_le32(&mms->write_out_ptr, 0);
113     bytestream_put_le16(&mms->write_out_ptr, packet_type);
114     bytestream_put_le16(&mms->write_out_ptr, 3); // direction to server
115 }
116
117 /** Add prefixes to MMST command packet. */
118 static void insert_command_prefixes(MMSContext *mms,
119         uint32_t prefix1, uint32_t prefix2)
120 {
121     bytestream_put_le32(&mms->write_out_ptr, prefix1); // first prefix
122     bytestream_put_le32(&mms->write_out_ptr, prefix2); // second prefix
123 }
124
125 /** Send a prepared MMST command packet. */
126 static int send_command_packet(MMSTContext *mmst)
127 {
128     MMSContext *mms  = &mmst->mms;
129     int len= mms->write_out_ptr - mms->out_buffer;
130     int exact_length = FFALIGN(len, 8);
131     int first_length= exact_length - 16;
132     int len8= first_length/8;
133     int write_result;
134
135     // update packet length fields.
136     AV_WL32(mms->out_buffer + 8, first_length);
137     AV_WL32(mms->out_buffer + 16, len8);
138     AV_WL32(mms->out_buffer + 32, len8-2);
139     memset(mms->write_out_ptr, 0, exact_length - len);
140
141     // write it out.
142     write_result= ffurl_write(mms->mms_hd, mms->out_buffer, exact_length);
143     if(write_result != exact_length) {
144         av_log(NULL, AV_LOG_ERROR,
145                "Failed to write data of length %d: %d (%s)\n",
146                exact_length, write_result,
147                write_result < 0 ? strerror(AVUNERROR(write_result)) :
148                    "The server closed the connection");
149         return AVERROR(EIO);
150     }
151
152     return 0;
153 }
154
155 static void mms_put_utf16(MMSContext *mms, const uint8_t *src)
156 {
157     AVIOContext bic;
158     int size = mms->write_out_ptr - mms->out_buffer;
159     int len;
160     ffio_init_context(&bic, mms->write_out_ptr,
161             sizeof(mms->out_buffer) - size, 1, NULL, NULL, NULL, NULL);
162
163     len = avio_put_str16le(&bic, src);
164     mms->write_out_ptr += len;
165 }
166
167 static int send_time_test_data(MMSTContext *mmst)
168 {
169     start_command_packet(mmst, CS_PKT_TIMING_DATA_REQUEST);
170     insert_command_prefixes(&mmst->mms, 0x00f0f0f0, 0x0004000b);
171     return send_command_packet(mmst);
172 }
173
174 static int send_protocol_select(MMSTContext *mmst)
175 {
176     char data_string[256];
177     MMSContext *mms = &mmst->mms;
178
179     start_command_packet(mmst, CS_PKT_PROTOCOL_SELECT);
180     insert_command_prefixes(mms, 0, 0xffffffff);
181     bytestream_put_le32(&mms->write_out_ptr, 0);          // maxFunnelBytes
182     bytestream_put_le32(&mms->write_out_ptr, 0x00989680); // maxbitRate
183     bytestream_put_le32(&mms->write_out_ptr, 2);          // funnelMode
184     snprintf(data_string, sizeof(data_string), "\\\\%d.%d.%d.%d\\%s\\%d",
185             (LOCAL_ADDRESS>>24)&0xff,
186             (LOCAL_ADDRESS>>16)&0xff,
187             (LOCAL_ADDRESS>>8)&0xff,
188             LOCAL_ADDRESS&0xff,
189             "TCP",                                        // or UDP
190             LOCAL_PORT);
191
192     mms_put_utf16(mms, data_string);
193     return send_command_packet(mmst);
194 }
195
196 static int send_media_file_request(MMSTContext *mmst)
197 {
198     MMSContext *mms = &mmst->mms;
199     start_command_packet(mmst, CS_PKT_MEDIA_FILE_REQUEST);
200     insert_command_prefixes(mms, 1, 0xffffffff);
201     bytestream_put_le32(&mms->write_out_ptr, 0);
202     bytestream_put_le32(&mms->write_out_ptr, 0);
203     mms_put_utf16(mms, mmst->path + 1); // +1 for skip "/"
204
205     return send_command_packet(mmst);
206 }
207
208 static void handle_packet_stream_changing_type(MMSTContext *mmst)
209 {
210     MMSContext *mms = &mmst->mms;
211     av_dlog(NULL, "Stream changing!\n");
212
213     // 40 is the packet header size, 7 is the prefix size.
214     mmst->header_packet_id= AV_RL32(mms->in_buffer + 40 + 7);
215     av_dlog(NULL, "Changed header prefix to 0x%x", mmst->header_packet_id);
216 }
217
218 static int send_keepalive_packet(MMSTContext *mmst)
219 {
220     // respond to a keepalive with a keepalive...
221     start_command_packet(mmst, CS_PKT_KEEPALIVE);
222     insert_command_prefixes(&mmst->mms, 1, 0x100FFFF);
223     return send_command_packet(mmst);
224 }
225
226 /** Pad media packets smaller than max_packet_size and/or adjust read position
227   * after a seek. */
228 static void pad_media_packet(MMSContext *mms)
229 {
230     if(mms->remaining_in_len<mms->asf_packet_len) {
231         int padding_size = mms->asf_packet_len - mms->remaining_in_len;
232         memset(mms->in_buffer + mms->remaining_in_len, 0, padding_size);
233         mms->remaining_in_len += padding_size;
234     }
235 }
236
237 /** Read incoming MMST media, header or command packet. */
238 static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
239 {
240     int read_result;
241     MMSSCPacketType packet_type= -1;
242     MMSContext *mms = &mmst->mms;
243     for(;;) {
244         read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer, 8);
245         if (read_result != 8) {
246             if(read_result < 0) {
247                 av_log(NULL, AV_LOG_ERROR,
248                        "Error reading packet header: %d (%s)\n",
249                        read_result, strerror(AVUNERROR(read_result)));
250                 packet_type = SC_PKT_CANCEL;
251             } else {
252                 av_log(NULL, AV_LOG_ERROR,
253                        "The server closed the connection\n");
254                 packet_type = SC_PKT_NO_DATA;
255             }
256             return packet_type;
257         }
258
259         // handle command packet.
260         if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {
261             int length_remaining, hr;
262
263             mmst->incoming_flags= mms->in_buffer[3];
264             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer+8, 4);
265             if(read_result != 4) {
266                 av_log(NULL, AV_LOG_ERROR,
267                        "Reading command packet length failed: %d (%s)\n",
268                        read_result,
269                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
270                            "The server closed the connection");
271                 return read_result < 0 ? read_result : AVERROR(EIO);
272             }
273
274             length_remaining= AV_RL32(mms->in_buffer+8) + 4;
275             av_dlog(NULL, "Length remaining is %d\n", length_remaining);
276             // read the rest of the packet.
277             if (length_remaining < 0
278                 || length_remaining > sizeof(mms->in_buffer) - 12) {
279                 av_log(NULL, AV_LOG_ERROR,
280                        "Incoming packet length %d exceeds bufsize %zu\n",
281                        length_remaining, sizeof(mms->in_buffer) - 12);
282                 return AVERROR_INVALIDDATA;
283             }
284             read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer + 12,
285                                             length_remaining) ;
286             if (read_result != length_remaining) {
287                 av_log(NULL, AV_LOG_ERROR,
288                        "Reading pkt data (length=%d) failed: %d (%s)\n",
289                        length_remaining, read_result,
290                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
291                            "The server closed the connection");
292                 return read_result < 0 ? read_result : AVERROR(EIO);
293             }
294             packet_type= AV_RL16(mms->in_buffer+36);
295             if (read_result >= 44 && (hr = AV_RL32(mms->in_buffer + 40))) {
296                 av_log(NULL, AV_LOG_ERROR,
297                        "Server sent a message with packet type 0x%x and error status code 0x%08x\n", packet_type, hr);
298                 return AVERROR(EINVAL);
299             }
300         } else {
301             int length_remaining;
302             int packet_id_type;
303             int tmp;
304
305             // note we cache the first 8 bytes,
306             // then fill up the buffer with the others
307             tmp                       = AV_RL16(mms->in_buffer + 6);
308             length_remaining          = (tmp - 8) & 0xffff;
309             mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);
310             packet_id_type            = mms->in_buffer[4];
311             mmst->incoming_flags      = mms->in_buffer[5];
312
313             if (length_remaining < 0
314                 || length_remaining > sizeof(mms->in_buffer) - 8) {
315                 av_log(NULL, AV_LOG_ERROR,
316                        "Data length %d is invalid or too large (max=%zu)\n",
317                        length_remaining, sizeof(mms->in_buffer));
318                 return AVERROR_INVALIDDATA;
319             }
320             mms->remaining_in_len    = length_remaining;
321             mms->read_in_ptr         = mms->in_buffer;
322             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
323             if(read_result != length_remaining) {
324                 av_log(NULL, AV_LOG_ERROR,
325                        "Failed to read packet data of size %d: %d (%s)\n",
326                        length_remaining, read_result,
327                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
328                            "The server closed the connection");
329                 return read_result < 0 ? read_result : AVERROR(EIO);
330             }
331
332             // if we successfully read everything.
333             if(packet_id_type == mmst->header_packet_id) {
334                 int err;
335                 packet_type = SC_PKT_ASF_HEADER;
336                 // Store the asf header
337                 if(!mms->header_parsed) {
338                     if ((err = av_reallocp(&mms->asf_header,
339                                            mms->asf_header_size +
340                                            mms->remaining_in_len)) < 0) {
341                         mms->asf_header_size = 0;
342                         return err;
343                     }
344                     memcpy(mms->asf_header + mms->asf_header_size,
345                            mms->read_in_ptr, mms->remaining_in_len);
346                     mms->asf_header_size += mms->remaining_in_len;
347                 }
348                 // 0x04 means asf header is sent in multiple packets.
349                 if (mmst->incoming_flags == 0x04)
350                     continue;
351             } else if(packet_id_type == mmst->packet_id) {
352                 packet_type = SC_PKT_ASF_MEDIA;
353             } else {
354                 av_dlog(NULL, "packet id type %d is old.", packet_id_type);
355                 continue;
356             }
357         }
358
359         // preprocess some packet type
360         if(packet_type == SC_PKT_KEEPALIVE) {
361             send_keepalive_packet(mmst);
362             continue;
363         } else if(packet_type == SC_PKT_STREAM_CHANGING) {
364             handle_packet_stream_changing_type(mmst);
365         } else if(packet_type == SC_PKT_ASF_MEDIA) {
366             pad_media_packet(mms);
367         }
368         return packet_type;
369     }
370 }
371
372 static int mms_safe_send_recv(MMSTContext *mmst,
373                               int (*send_fun)(MMSTContext *mmst),
374                               const MMSSCPacketType expect_type)
375 {
376     MMSSCPacketType type;
377     if(send_fun) {
378         int ret = send_fun(mmst);
379         if (ret < 0) {
380             av_dlog(NULL, "Send Packet error before expecting recv packet %d\n", expect_type);
381             return ret;
382         }
383     }
384
385     if ((type = get_tcp_server_response(mmst)) != expect_type) {
386         av_log(NULL, AV_LOG_ERROR,
387                "Corrupt stream (unexpected packet type 0x%x, expected 0x%x)\n",
388                type, expect_type);
389         return AVERROR_INVALIDDATA;
390     } else {
391         return 0;
392     }
393 }
394
395 static int send_media_header_request(MMSTContext *mmst)
396 {
397     MMSContext *mms = &mmst->mms;
398     start_command_packet(mmst, CS_PKT_MEDIA_HEADER_REQUEST);
399     insert_command_prefixes(mms, 1, 0);
400     bytestream_put_le32(&mms->write_out_ptr, 0);
401     bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
402     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
403     bytestream_put_le32(&mms->write_out_ptr, 0);
404     bytestream_put_le32(&mms->write_out_ptr, 0);
405     bytestream_put_le32(&mms->write_out_ptr, 0);
406
407     // the media preroll value in milliseconds?
408     bytestream_put_le32(&mms->write_out_ptr, 0);
409     bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
410     bytestream_put_le32(&mms->write_out_ptr, 2);
411     bytestream_put_le32(&mms->write_out_ptr, 0);
412
413     return send_command_packet(mmst);
414 }
415
416 /** Send the initial handshake. */
417 static int send_startup_packet(MMSTContext *mmst)
418 {
419     char data_string[256];
420     MMSContext *mms = &mmst->mms;
421     // SubscriberName is defined in MS specification linked below.
422     // The guid value can be any valid value.
423     // http://download.microsoft.com/
424     // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
425     snprintf(data_string, sizeof(data_string),
426             "NSPlayer/7.0.0.1956; {%s}; Host: %s",
427             "7E667F5D-A661-495E-A512-F55686DDA178", mmst->host);
428
429     start_command_packet(mmst, CS_PKT_INITIAL);
430     insert_command_prefixes(mms, 0, 0x0004000b);
431     bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
432     mms_put_utf16(mms, data_string);
433     return send_command_packet(mmst);
434 }
435
436 /** Send MMST stream selection command based on the AVStream->discard values. */
437 static int send_stream_selection_request(MMSTContext *mmst)
438 {
439     int i;
440     MMSContext *mms = &mmst->mms;
441     //  send the streams we want back...
442     start_command_packet(mmst, CS_PKT_STREAM_ID_REQUEST);
443     bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
444     for(i= 0; i<mms->stream_num; i++) {
445         bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
446         bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
447         bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
448     }
449     return send_command_packet(mmst);
450 }
451
452 static int send_close_packet(MMSTContext *mmst)
453 {
454     start_command_packet(mmst, CS_PKT_STREAM_CLOSE);
455     insert_command_prefixes(&mmst->mms, 1, 1);
456
457     return send_command_packet(mmst);
458 }
459
460 /** Close the MMSH/MMST connection */
461 static int mms_close(URLContext *h)
462 {
463     MMSTContext *mmst = (MMSTContext *)h->priv_data;
464     MMSContext *mms   = &mmst->mms;
465     if(mms->mms_hd) {
466         send_close_packet(mmst);
467         ffurl_close(mms->mms_hd);
468     }
469
470     /* free all separately allocated pointers in mms */
471     av_free(mms->streams);
472     av_free(mms->asf_header);
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 = h->priv_data;
505     MMSContext *mms;
506     int port, err;
507     char tcpname[256];
508
509     h->is_streamed = 1;
510     mms = &mmst->mms;
511
512     // only for MMS over TCP, so set proto = NULL
513     av_url_split(NULL, 0, NULL, 0,
514             mmst->host, sizeof(mmst->host), &port, mmst->path,
515             sizeof(mmst->path), uri);
516
517     if(port<0)
518         port = 1755; // defaut mms protocol port
519
520     // establish tcp connection.
521     ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mmst->host, port, NULL);
522     err = ffurl_open(&mms->mms_hd, tcpname, AVIO_FLAG_READ_WRITE,
523                      &h->interrupt_callback, NULL);
524     if (err)
525         goto fail;
526
527     mmst->packet_id        = 3;          // default, initial value.
528     mmst->header_packet_id = 2;          // default, initial value.
529     err = mms_safe_send_recv(mmst, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);
530     if (err)
531         goto fail;
532     err = mms_safe_send_recv(mmst, send_time_test_data, SC_PKT_TIMING_TEST_REPLY);
533     if (err)
534         goto fail;
535     err = mms_safe_send_recv(mmst, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);
536     if (err)
537         goto fail;
538     err = mms_safe_send_recv(mmst, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);
539     if (err)
540         goto fail;
541     err = mms_safe_send_recv(mmst, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);
542     if (err)
543         goto fail;
544     err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_HEADER);
545     if (err)
546         goto fail;
547     if((mmst->incoming_flags != 0X08) && (mmst->incoming_flags != 0X0C)) {
548         av_log(NULL, AV_LOG_ERROR,
549                "The server does not support MMST (try MMSH or RTSP)\n");
550         err = AVERROR(EINVAL);
551         goto fail;
552     }
553     err = ff_mms_asf_header_parser(mms);
554     if (err) {
555         av_dlog(NULL, "asf header parsed failed!\n");
556         goto fail;
557     }
558     mms->header_parsed = 1;
559
560     if (!mms->asf_packet_len || !mms->stream_num)
561         goto fail;
562
563     clear_stream_buffers(mms);
564     err = mms_safe_send_recv(mmst, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);
565     if (err)
566         goto fail;
567     // send media packet request
568     err = mms_safe_send_recv(mmst, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);
569     if (err) {
570         goto fail;
571     }
572     av_dlog(NULL, "Leaving open (success)\n");
573     return 0;
574 fail:
575     mms_close(h);
576     av_dlog(NULL, "Leaving open (failure: %d)\n", err);
577     return err;
578 }
579
580 /** Read ASF data through the protocol. */
581 static int mms_read(URLContext *h, uint8_t *buf, int size)
582 {
583     /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */
584     MMSTContext *mmst = h->priv_data;
585     MMSContext *mms   = &mmst->mms;
586     int result = 0;
587
588     do {
589         if(mms->asf_header_read_size < mms->asf_header_size) {
590             /* Read from ASF header buffer */
591             result = ff_mms_read_header(mms, buf, size);
592         } else if(mms->remaining_in_len) {
593             /* Read remaining packet data to buffer.
594              * the result can not be zero because remaining_in_len is positive.*/
595             result = ff_mms_read_data(mms, buf, size);
596         } else {
597             /* Read from network */
598             int err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_MEDIA);
599             if (err == 0) {
600                 if(mms->remaining_in_len>mms->asf_packet_len) {
601                     av_log(NULL, AV_LOG_ERROR,
602                            "Incoming pktlen %d is larger than ASF pktsize %d\n",
603                            mms->remaining_in_len, mms->asf_packet_len);
604                     result= AVERROR(EIO);
605                 } else {
606                     // copy the data to the packet buffer.
607                     result = ff_mms_read_data(mms, buf, size);
608                     if (result == 0) {
609                         av_dlog(NULL, "Read ASF media packet size is zero!\n");
610                         break;
611                     }
612                 }
613             } else {
614                 av_dlog(NULL, "read packet error!\n");
615                 break;
616             }
617         }
618     } while(!result); // only return one packet.
619     return result;
620 }
621
622 URLProtocol ff_mmst_protocol = {
623     .name           = "mmst",
624     .url_open       = mms_open,
625     .url_read       = mms_read,
626     .url_close      = mms_close,
627     .priv_data_size = sizeof(MMSTContext),
628     .flags          = URL_PROTOCOL_FLAG_NETWORK,
629 };