Prefix all _demuxer, _muxer, _protocol from libavformat and libavdevice.
[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     dprintf(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     dprintf(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             dprintf(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                 dprintf(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             dprintf(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         dprintf(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     dprintf(NULL, "Leaving open (success)\n");
575     return 0;
576 fail:
577     mms_close(h);
578     dprintf(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                         dprintf(NULL, "read asf media paket size is zero!\n");
612                         break;
613                     }
614                 }
615             } else {
616                 dprintf(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 };