avformat/mlvdec: read_string() received unsigned size, make the argument unsigned
[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 MMSTContext {
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 int 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     if (len < 0)
165         return len;
166     mms->write_out_ptr += len;
167     return 0;
168 }
169
170 static int send_time_test_data(MMSTContext *mmst)
171 {
172     start_command_packet(mmst, CS_PKT_TIMING_DATA_REQUEST);
173     insert_command_prefixes(&mmst->mms, 0x00f0f0f0, 0x0004000b);
174     return send_command_packet(mmst);
175 }
176
177 static int send_protocol_select(MMSTContext *mmst)
178 {
179     int ret;
180     char data_string[256];
181     MMSContext *mms = &mmst->mms;
182
183     start_command_packet(mmst, CS_PKT_PROTOCOL_SELECT);
184     insert_command_prefixes(mms, 0, 0xffffffff);
185     bytestream_put_le32(&mms->write_out_ptr, 0);          // maxFunnelBytes
186     bytestream_put_le32(&mms->write_out_ptr, 0x00989680); // maxbitRate
187     bytestream_put_le32(&mms->write_out_ptr, 2);          // funnelMode
188     snprintf(data_string, sizeof(data_string), "\\\\%d.%d.%d.%d\\%s\\%d",
189             (LOCAL_ADDRESS>>24)&0xff,
190             (LOCAL_ADDRESS>>16)&0xff,
191             (LOCAL_ADDRESS>>8)&0xff,
192             LOCAL_ADDRESS&0xff,
193             "TCP",                                        // or UDP
194             LOCAL_PORT);
195
196     if ((ret = mms_put_utf16(mms, data_string)) < 0)
197         return ret;
198     return send_command_packet(mmst);
199 }
200
201 static int send_media_file_request(MMSTContext *mmst)
202 {
203     int ret;
204     MMSContext *mms = &mmst->mms;
205     start_command_packet(mmst, CS_PKT_MEDIA_FILE_REQUEST);
206     insert_command_prefixes(mms, 1, 0xffffffff);
207     bytestream_put_le32(&mms->write_out_ptr, 0);
208     bytestream_put_le32(&mms->write_out_ptr, 0);
209     if ((ret = mms_put_utf16(mms, mmst->path + 1)) < 0) // +1 for skip "/"
210         return ret;
211
212     return send_command_packet(mmst);
213 }
214
215 static void handle_packet_stream_changing_type(MMSTContext *mmst)
216 {
217     MMSContext *mms = &mmst->mms;
218     av_log(NULL, AV_LOG_TRACE, "Stream changing!\n");
219
220     // 40 is the packet header size, 7 is the prefix size.
221     mmst->header_packet_id= AV_RL32(mms->in_buffer + 40 + 7);
222     av_log(NULL, AV_LOG_TRACE, "Changed header prefix to 0x%x", mmst->header_packet_id);
223 }
224
225 static int send_keepalive_packet(MMSTContext *mmst)
226 {
227     // respond to a keepalive with a keepalive...
228     start_command_packet(mmst, CS_PKT_KEEPALIVE);
229     insert_command_prefixes(&mmst->mms, 1, 0x100FFFF);
230     return send_command_packet(mmst);
231 }
232
233 /** Pad media packets smaller than max_packet_size and/or adjust read position
234   * after a seek. */
235 static void pad_media_packet(MMSContext *mms)
236 {
237     if(mms->remaining_in_len<mms->asf_packet_len) {
238         int padding_size = mms->asf_packet_len - mms->remaining_in_len;
239         memset(mms->in_buffer + mms->remaining_in_len, 0, padding_size);
240         mms->remaining_in_len += padding_size;
241     }
242 }
243
244 /** Read incoming MMST media, header or command packet. */
245 static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)
246 {
247     int read_result;
248     MMSSCPacketType packet_type= -1;
249     MMSContext *mms = &mmst->mms;
250     for(;;) {
251         read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer, 8);
252         if (read_result != 8) {
253             if(read_result < 0) {
254                 av_log(NULL, AV_LOG_ERROR,
255                        "Error reading packet header: %d (%s)\n",
256                        read_result, strerror(AVUNERROR(read_result)));
257                 packet_type = SC_PKT_CANCEL;
258             } else {
259                 av_log(NULL, AV_LOG_ERROR,
260                        "The server closed the connection\n");
261                 packet_type = SC_PKT_NO_DATA;
262             }
263             return packet_type;
264         }
265
266         // handle command packet.
267         if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {
268             int length_remaining, hr;
269
270             mmst->incoming_flags= mms->in_buffer[3];
271             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer+8, 4);
272             if(read_result != 4) {
273                 av_log(NULL, AV_LOG_ERROR,
274                        "Reading command packet length failed: %d (%s)\n",
275                        read_result,
276                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
277                            "The server closed the connection");
278                 return read_result < 0 ? read_result : AVERROR(EIO);
279             }
280
281             length_remaining= AV_RL32(mms->in_buffer+8) + 4;
282             av_log(NULL, AV_LOG_TRACE, "Length remaining is %d\n", length_remaining);
283             // read the rest of the packet.
284             if (length_remaining < 0
285                 || length_remaining > sizeof(mms->in_buffer) - 12) {
286                 av_log(NULL, AV_LOG_ERROR,
287                        "Incoming packet length %d exceeds bufsize %"SIZE_SPECIFIER"\n",
288                        length_remaining, sizeof(mms->in_buffer) - 12);
289                 return AVERROR_INVALIDDATA;
290             }
291             read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer + 12,
292                                             length_remaining) ;
293             if (read_result != length_remaining) {
294                 av_log(NULL, AV_LOG_ERROR,
295                        "Reading pkt data (length=%d) failed: %d (%s)\n",
296                        length_remaining, read_result,
297                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
298                            "The server closed the connection");
299                 return read_result < 0 ? read_result : AVERROR(EIO);
300             }
301             packet_type= AV_RL16(mms->in_buffer+36);
302             if (read_result >= 44 && (hr = AV_RL32(mms->in_buffer + 40))) {
303                 av_log(NULL, AV_LOG_ERROR,
304                        "Server sent a message with packet type 0x%x and error status code 0x%08x\n", packet_type, hr);
305                 return AVERROR(EINVAL);
306             }
307         } else {
308             int length_remaining;
309             int packet_id_type;
310             int tmp;
311
312             // note we cache the first 8 bytes,
313             // then fill up the buffer with the others
314             tmp                       = AV_RL16(mms->in_buffer + 6);
315             length_remaining          = (tmp - 8) & 0xffff;
316             mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);
317             packet_id_type            = mms->in_buffer[4];
318             mmst->incoming_flags      = mms->in_buffer[5];
319
320             if (length_remaining < 0
321                 || length_remaining > sizeof(mms->in_buffer) - 8) {
322                 av_log(NULL, AV_LOG_ERROR,
323                        "Data length %d is invalid or too large (max=%"SIZE_SPECIFIER")\n",
324                        length_remaining, sizeof(mms->in_buffer));
325                 return AVERROR_INVALIDDATA;
326             }
327             mms->remaining_in_len    = length_remaining;
328             mms->read_in_ptr         = mms->in_buffer;
329             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);
330             if(read_result != length_remaining) {
331                 av_log(NULL, AV_LOG_ERROR,
332                        "Failed to read packet data of size %d: %d (%s)\n",
333                        length_remaining, read_result,
334                        read_result < 0 ? strerror(AVUNERROR(read_result)) :
335                            "The server closed the connection");
336                 return read_result < 0 ? read_result : AVERROR(EIO);
337             }
338
339             // if we successfully read everything.
340             if(packet_id_type == mmst->header_packet_id) {
341                 int err;
342                 packet_type = SC_PKT_ASF_HEADER;
343                 // Store the asf header
344                 if(!mms->header_parsed) {
345                     if ((err = av_reallocp(&mms->asf_header,
346                                            mms->asf_header_size +
347                                            mms->remaining_in_len)) < 0) {
348                         mms->asf_header_size = 0;
349                         return err;
350                     }
351                     memcpy(mms->asf_header + mms->asf_header_size,
352                            mms->read_in_ptr, mms->remaining_in_len);
353                     mms->asf_header_size += mms->remaining_in_len;
354                 }
355                 // 0x04 means asf header is sent in multiple packets.
356                 if (mmst->incoming_flags == 0x04)
357                     continue;
358             } else if(packet_id_type == mmst->packet_id) {
359                 packet_type = SC_PKT_ASF_MEDIA;
360             } else {
361                 av_log(NULL, AV_LOG_TRACE, "packet id type %d is old.", packet_id_type);
362                 continue;
363             }
364         }
365
366         // preprocess some packet type
367         if(packet_type == SC_PKT_KEEPALIVE) {
368             send_keepalive_packet(mmst);
369             continue;
370         } else if(packet_type == SC_PKT_STREAM_CHANGING) {
371             handle_packet_stream_changing_type(mmst);
372         } else if(packet_type == SC_PKT_ASF_MEDIA) {
373             pad_media_packet(mms);
374         }
375         return packet_type;
376     }
377 }
378
379 static int mms_safe_send_recv(MMSTContext *mmst,
380                               int (*send_fun)(MMSTContext *mmst),
381                               const MMSSCPacketType expect_type)
382 {
383     MMSSCPacketType type;
384     if(send_fun) {
385         int ret = send_fun(mmst);
386         if (ret < 0) {
387             av_log(NULL, AV_LOG_TRACE, "Send Packet error before expecting recv packet %d\n", expect_type);
388             return ret;
389         }
390     }
391
392     if ((type = get_tcp_server_response(mmst)) != expect_type) {
393         av_log(NULL, AV_LOG_ERROR,
394                "Corrupt stream (unexpected packet type 0x%x, expected 0x%x)\n",
395                type, expect_type);
396         return AVERROR_INVALIDDATA;
397     } else {
398         return 0;
399     }
400 }
401
402 static int send_media_header_request(MMSTContext *mmst)
403 {
404     MMSContext *mms = &mmst->mms;
405     start_command_packet(mmst, CS_PKT_MEDIA_HEADER_REQUEST);
406     insert_command_prefixes(mms, 1, 0);
407     bytestream_put_le32(&mms->write_out_ptr, 0);
408     bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
409     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
410     bytestream_put_le32(&mms->write_out_ptr, 0);
411     bytestream_put_le32(&mms->write_out_ptr, 0);
412     bytestream_put_le32(&mms->write_out_ptr, 0);
413
414     // the media preroll value in milliseconds?
415     bytestream_put_le32(&mms->write_out_ptr, 0);
416     bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
417     bytestream_put_le32(&mms->write_out_ptr, 2);
418     bytestream_put_le32(&mms->write_out_ptr, 0);
419
420     return send_command_packet(mmst);
421 }
422
423 /** Send the initial handshake. */
424 static int send_startup_packet(MMSTContext *mmst)
425 {
426     char data_string[256];
427     int ret;
428     MMSContext *mms = &mmst->mms;
429     // SubscriberName is defined in MS specification linked below.
430     // The GUID value can be any valid value.
431     // http://download.microsoft.com/
432     // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
433     snprintf(data_string, sizeof(data_string),
434             "NSPlayer/7.0.0.1956; {%s}; Host: %s",
435             "7E667F5D-A661-495E-A512-F55686DDA178", mmst->host);
436
437     start_command_packet(mmst, CS_PKT_INITIAL);
438     insert_command_prefixes(mms, 0, 0x0004000b);
439     bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
440     if ((ret = mms_put_utf16(mms, data_string)) < 0)
441         return ret;
442     return send_command_packet(mmst);
443 }
444
445 /** Send MMST stream selection command based on the AVStream->discard values. */
446 static int send_stream_selection_request(MMSTContext *mmst)
447 {
448     int i;
449     MMSContext *mms = &mmst->mms;
450     //  send the streams we want back...
451     start_command_packet(mmst, CS_PKT_STREAM_ID_REQUEST);
452     bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
453     for(i= 0; i<mms->stream_num; i++) {
454         bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
455         bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
456         bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
457     }
458     return send_command_packet(mmst);
459 }
460
461 static int send_close_packet(MMSTContext *mmst)
462 {
463     start_command_packet(mmst, CS_PKT_STREAM_CLOSE);
464     insert_command_prefixes(&mmst->mms, 1, 1);
465
466     return send_command_packet(mmst);
467 }
468
469 /** Close the MMSH/MMST connection */
470 static int mms_close(URLContext *h)
471 {
472     MMSTContext *mmst = (MMSTContext *)h->priv_data;
473     MMSContext *mms   = &mmst->mms;
474     if(mms->mms_hd) {
475         send_close_packet(mmst);
476         ffurl_close(mms->mms_hd);
477     }
478
479     /* free all separately allocated pointers in mms */
480     av_freep(&mms->streams);
481     av_freep(&mms->asf_header);
482
483     return 0;
484 }
485
486 static int send_media_packet_request(MMSTContext *mmst)
487 {
488     MMSContext *mms = &mmst->mms;
489     start_command_packet(mmst, CS_PKT_START_FROM_PKT_ID);
490     insert_command_prefixes(mms, 1, 0x0001FFFF);
491     bytestream_put_le64(&mms->write_out_ptr, 0);          // seek timestamp
492     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // unknown
493     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // packet offset
494     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
495     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
496     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
497     bytestream_put_byte(&mms->write_out_ptr, 0x00);       // stream time limit flag
498
499     mmst->packet_id++;                                     // new packet_id
500     bytestream_put_le32(&mms->write_out_ptr, mmst->packet_id);
501     return send_command_packet(mmst);
502 }
503
504
505 static void clear_stream_buffers(MMSContext *mms)
506 {
507     mms->remaining_in_len = 0;
508     mms->read_in_ptr      = mms->in_buffer;
509 }
510
511 static int mms_open(URLContext *h, const char *uri, int flags)
512 {
513     MMSTContext *mmst = h->priv_data;
514     MMSContext *mms;
515     int port, err;
516     char tcpname[256];
517
518     h->is_streamed = 1;
519     mms = &mmst->mms;
520
521     // only for MMS over TCP, so set proto = NULL
522     av_url_split(NULL, 0, NULL, 0,
523             mmst->host, sizeof(mmst->host), &port, mmst->path,
524             sizeof(mmst->path), uri);
525
526     if(port<0)
527         port = 1755; // default MMS protocol port
528
529     // establish tcp connection.
530     ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mmst->host, port, NULL);
531     err = ffurl_open_whitelist(&mms->mms_hd, tcpname, AVIO_FLAG_READ_WRITE,
532                                &h->interrupt_callback, NULL,
533                                h->protocol_whitelist, h->protocol_blacklist, h);
534     if (err)
535         goto fail;
536
537     mmst->packet_id        = 3;          // default, initial value.
538     mmst->header_packet_id = 2;          // default, initial value.
539     err = mms_safe_send_recv(mmst, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);
540     if (err)
541         goto fail;
542     err = mms_safe_send_recv(mmst, send_time_test_data, SC_PKT_TIMING_TEST_REPLY);
543     if (err)
544         goto fail;
545     err = mms_safe_send_recv(mmst, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);
546     if (err)
547         goto fail;
548     err = mms_safe_send_recv(mmst, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);
549     if (err)
550         goto fail;
551     err = mms_safe_send_recv(mmst, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);
552     if (err)
553         goto fail;
554     err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_HEADER);
555     if (err)
556         goto fail;
557     if((mmst->incoming_flags != 0X08) && (mmst->incoming_flags != 0X0C)) {
558         av_log(NULL, AV_LOG_ERROR,
559                "The server does not support MMST (try MMSH or RTSP)\n");
560         err = AVERROR(EINVAL);
561         goto fail;
562     }
563     err = ff_mms_asf_header_parser(mms);
564     if (err) {
565         av_log(NULL, AV_LOG_TRACE, "asf header parsed failed!\n");
566         goto fail;
567     }
568     mms->header_parsed = 1;
569
570     if (!mms->asf_packet_len || !mms->stream_num)
571         goto fail;
572
573     clear_stream_buffers(mms);
574     err = mms_safe_send_recv(mmst, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);
575     if (err)
576         goto fail;
577     // send media packet request
578     err = mms_safe_send_recv(mmst, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);
579     if (err) {
580         goto fail;
581     }
582     av_log(NULL, AV_LOG_TRACE, "Leaving open (success)\n");
583     return 0;
584 fail:
585     mms_close(h);
586     av_log(NULL, AV_LOG_TRACE, "Leaving open (failure: %d)\n", err);
587     return err;
588 }
589
590 /** Read ASF data through the protocol. */
591 static int mms_read(URLContext *h, uint8_t *buf, int size)
592 {
593     /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */
594     MMSTContext *mmst = h->priv_data;
595     MMSContext *mms   = &mmst->mms;
596     int result = 0;
597
598     do {
599         if(mms->asf_header_read_size < mms->asf_header_size) {
600             /* Read from ASF header buffer */
601             result = ff_mms_read_header(mms, buf, size);
602         } else if(mms->remaining_in_len) {
603             /* Read remaining packet data to buffer.
604              * the result can not be zero because remaining_in_len is positive.*/
605             result = ff_mms_read_data(mms, buf, size);
606         } else {
607             /* Read from network */
608             int err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_MEDIA);
609             if (err == 0) {
610                 if(mms->remaining_in_len>mms->asf_packet_len) {
611                     av_log(NULL, AV_LOG_ERROR,
612                            "Incoming pktlen %d is larger than ASF pktsize %d\n",
613                            mms->remaining_in_len, mms->asf_packet_len);
614                     result= AVERROR(EIO);
615                 } else {
616                     // copy the data to the packet buffer.
617                     result = ff_mms_read_data(mms, buf, size);
618                     if (result == 0) {
619                         av_log(NULL, AV_LOG_TRACE, "Read ASF media packet size is zero!\n");
620                         break;
621                     }
622                 }
623             } else {
624                 av_log(NULL, AV_LOG_TRACE, "read packet error!\n");
625                 break;
626             }
627         }
628     } while(!result); // only return one packet.
629     return result;
630 }
631
632 const URLProtocol ff_mmst_protocol = {
633     .name           = "mmst",
634     .url_open       = mms_open,
635     .url_read       = mms_read,
636     .url_close      = mms_close,
637     .priv_data_size = sizeof(MMSTContext),
638     .flags          = URL_PROTOCOL_FLAG_NETWORK,
639 };