a2b55b5c8e21567ac8fe4d86506a9b38c42d625d
[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 "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             if (read_result >= 44 && (hr = AV_RL32(mms->in_buffer + 40))) {
294                 av_log(NULL, AV_LOG_ERROR,
295                        "Server sent a message with packet type 0x%x and error status code 0x%08x\n", packet_type, hr);
296                 return AVERROR_UNKNOWN;
297             }
298         } else {
299             int length_remaining;
300             int packet_id_type;
301             int tmp;
302
303             // note we cache the first 8 bytes,
304             // then fill up the buffer with the others
305             tmp                       = AV_RL16(mms->in_buffer + 6);
306             length_remaining          = (tmp - 8) & 0xffff;
307             mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);
308             packet_id_type            = mms->in_buffer[4];
309             mmst->incoming_flags      = mms->in_buffer[5];
310
311             if (length_remaining < 0
312                 || length_remaining > sizeof(mms->in_buffer) - 8) {
313                 av_log(NULL, AV_LOG_ERROR,
314                        "Data length %d is invalid or too large (max=%zu)\n",
315                        length_remaining, sizeof(mms->in_buffer));
316                 return AVERROR_INVALIDDATA;
317             }
318             mms->remaining_in_len    = length_remaining;
319             mms->read_in_ptr         = mms->in_buffer;
320             read_result= url_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
321             if(read_result != length_remaining) {
322                 av_log(NULL, AV_LOG_ERROR,
323                        "Failed to read packet data of size %d: %d (%s)\n",
324                        length_remaining, read_result,
325                        read_result < 0 ? strerror(read_result) :
326                            "The server closed the connection");
327                 return read_result < 0 ? read_result : AVERROR_IO;
328             }
329
330             // if we successfully read everything.
331             if(packet_id_type == mmst->header_packet_id) {
332                 packet_type = SC_PKT_ASF_HEADER;
333                 // Store the asf header
334                 if(!mms->header_parsed) {
335                     void *p = av_realloc(mms->asf_header,
336                                   mms->asf_header_size + mms->remaining_in_len);
337                     if (!p) {
338                         av_freep(&mms->asf_header);
339                         return AVERROR(ENOMEM);
340                     }
341                     mms->asf_header = p;
342                     memcpy(mms->asf_header + mms->asf_header_size,
343                            mms->read_in_ptr, mms->remaining_in_len);
344                     mms->asf_header_size += mms->remaining_in_len;
345                 }
346                 // 0x04 means asf header is sent in multiple packets.
347                 if (mmst->incoming_flags == 0x04)
348                     continue;
349             } else if(packet_id_type == mmst->packet_id) {
350                 packet_type = SC_PKT_ASF_MEDIA;
351             } else {
352                 av_dlog(NULL, "packet id type %d is old.", packet_id_type);
353                 continue;
354             }
355         }
356
357         // preprocess some packet type
358         if(packet_type == SC_PKT_KEEPALIVE) {
359             send_keepalive_packet(mmst);
360             continue;
361         } else if(packet_type == SC_PKT_STREAM_CHANGING) {
362             handle_packet_stream_changing_type(mmst);
363         } else if(packet_type == SC_PKT_ASF_MEDIA) {
364             pad_media_packet(mms);
365         }
366         return packet_type;
367     }
368 }
369
370 static int mms_safe_send_recv(MMSTContext *mmst,
371                               int (*send_fun)(MMSTContext *mmst),
372                               const MMSSCPacketType expect_type)
373 {
374     MMSSCPacketType type;
375     if(send_fun) {
376         int ret = send_fun(mmst);
377         if (ret < 0) {
378             av_dlog(NULL, "Send Packet error before expecting recv packet %d\n", expect_type);
379             return ret;
380         }
381     }
382
383     if ((type = get_tcp_server_response(mmst)) != expect_type) {
384         av_log(NULL, AV_LOG_ERROR,
385                "Corrupt stream (unexpected packet type 0x%x, expected 0x%x)\n",
386                type, expect_type);
387         return AVERROR_INVALIDDATA;
388     } else {
389         return 0;
390     }
391 }
392
393 static int send_media_header_request(MMSTContext *mmst)
394 {
395     MMSContext *mms = &mmst->mms;
396     start_command_packet(mmst, CS_PKT_MEDIA_HEADER_REQUEST);
397     insert_command_prefixes(mms, 1, 0);
398     bytestream_put_le32(&mms->write_out_ptr, 0);
399     bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
400     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
401     bytestream_put_le32(&mms->write_out_ptr, 0);
402     bytestream_put_le32(&mms->write_out_ptr, 0);
403     bytestream_put_le32(&mms->write_out_ptr, 0);
404
405     // the media preroll value in milliseconds?
406     bytestream_put_le32(&mms->write_out_ptr, 0);
407     bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
408     bytestream_put_le32(&mms->write_out_ptr, 2);
409     bytestream_put_le32(&mms->write_out_ptr, 0);
410
411     return send_command_packet(mmst);
412 }
413
414 /** Send the initial handshake. */
415 static int send_startup_packet(MMSTContext *mmst)
416 {
417     char data_string[256];
418     MMSContext *mms = &mmst->mms;
419     // SubscriberName is defined in MS specification linked below.
420     // The guid value can be any valid value.
421     // http://download.microsoft.com/
422     // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
423     snprintf(data_string, sizeof(data_string),
424             "NSPlayer/7.0.0.1956; {%s}; Host: %s",
425             "7E667F5D-A661-495E-A512-F55686DDA178", mmst->host);
426
427     start_command_packet(mmst, CS_PKT_INITIAL);
428     insert_command_prefixes(mms, 0, 0x0004000b);
429     bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
430     mms_put_utf16(mms, data_string);
431     return send_command_packet(mmst);
432 }
433
434 /** Send MMST stream selection command based on the AVStream->discard values. */
435 static int send_stream_selection_request(MMSTContext *mmst)
436 {
437     int i;
438     MMSContext *mms = &mmst->mms;
439     //  send the streams we want back...
440     start_command_packet(mmst, CS_PKT_STREAM_ID_REQUEST);
441     bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
442     for(i= 0; i<mms->stream_num; i++) {
443         bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
444         bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
445         bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
446     }
447     return send_command_packet(mmst);
448 }
449
450 static int send_close_packet(MMSTContext *mmst)
451 {
452     start_command_packet(mmst, CS_PKT_STREAM_CLOSE);
453     insert_command_prefixes(&mmst->mms, 1, 1);
454
455     return send_command_packet(mmst);
456 }
457
458 /** Close the MMSH/MMST connection */
459 static int mms_close(URLContext *h)
460 {
461     MMSTContext *mmst = (MMSTContext *)h->priv_data;
462     MMSContext *mms   = &mmst->mms;
463     if(mms->mms_hd) {
464         send_close_packet(mmst);
465         url_close(mms->mms_hd);
466     }
467
468     /* free all separately allocated pointers in mms */
469     av_free(mms->streams);
470     av_free(mms->asf_header);
471     av_freep(&h->priv_data);
472
473     return 0;
474 }
475
476 static int send_media_packet_request(MMSTContext *mmst)
477 {
478     MMSContext *mms = &mmst->mms;
479     start_command_packet(mmst, CS_PKT_START_FROM_PKT_ID);
480     insert_command_prefixes(mms, 1, 0x0001FFFF);
481     bytestream_put_le64(&mms->write_out_ptr, 0);          // seek timestamp
482     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // unknown
483     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // packet offset
484     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
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, 0x00);       // stream time limit flag
488
489     mmst->packet_id++;                                     // new packet_id
490     bytestream_put_le32(&mms->write_out_ptr, mmst->packet_id);
491     return send_command_packet(mmst);
492 }
493
494
495 static void clear_stream_buffers(MMSContext *mms)
496 {
497     mms->remaining_in_len = 0;
498     mms->read_in_ptr      = mms->in_buffer;
499 }
500
501 static int mms_open(URLContext *h, const char *uri, int flags)
502 {
503     MMSTContext *mmst;
504     MMSContext *mms;
505     int port, err;
506     char tcpname[256];
507
508     h->is_streamed = 1;
509     mmst = h->priv_data = av_mallocz(sizeof(MMSTContext));
510     if (!h->priv_data)
511         return AVERROR(ENOMEM);
512     mms = &mmst->mms;
513
514     // only for MMS over TCP, so set proto = NULL
515     av_url_split(NULL, 0, NULL, 0,
516             mmst->host, sizeof(mmst->host), &port, mmst->path,
517             sizeof(mmst->path), uri);
518
519     if(port<0)
520         port = 1755; // defaut mms protocol port
521
522     // establish tcp connection.
523     ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mmst->host, port, NULL);
524     err = url_open(&mms->mms_hd, tcpname, URL_RDWR);
525     if (err)
526         goto fail;
527
528     mmst->packet_id        = 3;          // default, initial value.
529     mmst->header_packet_id = 2;          // default, initial value.
530     err = mms_safe_send_recv(mmst, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);
531     if (err)
532         goto fail;
533     err = mms_safe_send_recv(mmst, send_time_test_data, SC_PKT_TIMING_TEST_REPLY);
534     if (err)
535         goto fail;
536     err = mms_safe_send_recv(mmst, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);
537     if (err)
538         goto fail;
539     err = mms_safe_send_recv(mmst, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);
540     if (err)
541         goto fail;
542     err = mms_safe_send_recv(mmst, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);
543     if (err)
544         goto fail;
545     err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_HEADER);
546     if (err)
547         goto fail;
548     if((mmst->incoming_flags != 0X08) && (mmst->incoming_flags != 0X0C)) {
549         av_log(NULL, AV_LOG_ERROR,
550                "The server does not support MMST (try MMSH or RTSP)\n");
551         err = AVERROR_NOFMT;
552         goto fail;
553     }
554     err = ff_mms_asf_header_parser(mms);
555     if (err) {
556         av_dlog(NULL, "asf header parsed failed!\n");
557         goto fail;
558     }
559     mms->header_parsed = 1;
560
561     if (!mms->asf_packet_len || !mms->stream_num)
562         goto fail;
563
564     clear_stream_buffers(mms);
565     err = mms_safe_send_recv(mmst, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);
566     if (err)
567         goto fail;
568     // send media packet request
569     err = mms_safe_send_recv(mmst, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);
570     if (err) {
571         goto fail;
572     }
573     av_dlog(NULL, "Leaving open (success)\n");
574     return 0;
575 fail:
576     mms_close(h);
577     av_dlog(NULL, "Leaving open (failure: %d)\n", err);
578     return err;
579 }
580
581 /** Read ASF data through the protocol. */
582 static int mms_read(URLContext *h, uint8_t *buf, int size)
583 {
584     /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */
585     MMSTContext *mmst = h->priv_data;
586     MMSContext *mms   = &mmst->mms;
587     int result = 0;
588
589     do {
590         if(mms->asf_header_read_size < mms->asf_header_size) {
591             /* Read from ASF header buffer */
592             result = ff_mms_read_header(mms, buf, size);
593         } else if(mms->remaining_in_len) {
594             /* Read remaining packet data to buffer.
595              * the result can not be zero because remaining_in_len is positive.*/
596             result = ff_mms_read_data(mms, buf, size);
597         } else {
598             /* Read from network */
599             int err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_MEDIA);
600             if (err == 0) {
601                 if(mms->remaining_in_len>mms->asf_packet_len) {
602                     av_log(NULL, AV_LOG_ERROR,
603                            "Incoming pktlen %d is larger than ASF pktsize %d\n",
604                            mms->remaining_in_len, mms->asf_packet_len);
605                     result= AVERROR_IO;
606                 } else {
607                     // copy the data to the packet buffer.
608                     result = ff_mms_read_data(mms, buf, size);
609                     if (result == 0) {
610                         av_dlog(NULL, "read asf media paket size is zero!\n");
611                         break;
612                     }
613                 }
614             } else {
615                 av_dlog(NULL, "read packet error!\n");
616                 break;
617             }
618         }
619     } while(!result); // only return one packet.
620     return result;
621 }
622
623 URLProtocol ff_mmst_protocol = {
624     "mmst",
625     mms_open,
626     mms_read,
627     NULL, // write
628     NULL, // seek
629     mms_close,
630 };