text: /*
   * MMS protocol over HTTP
   * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /*
   * Reference
   * Windows Media HTTP Streaming Protocol.
   * http://msdn.microsoft.com/en-us/library/cc251059(PROT.10).aspx
   */
  
  #include <string.h>
  #include "libavutil/intreadwrite.h"
  #include "libavutil/avstring.h"
  #include "libavutil/opt.h"
  #include "internal.h"
  #include "mms.h"
  #include "asf.h"
  #include "http.h"
  #include "url.h"
  
  #define CHUNK_HEADER_LENGTH 4   // 2bytes chunk type and 2bytes chunk length.
  #define EXT_HEADER_LENGTH   8   // 4bytes sequence, 2bytes useless and 2bytes chunk length.
  
  // see Ref 2.2.1.8
  #define USERAGENT  "User-Agent: NSPlayer/4.1.0.3856\r\n"
  // see Ref 2.2.1.4.33
  // the GUID value can be changed to any valid value.
  #define CLIENTGUID "Pragma: xClientGUID={c77e7400-738a-11d2-9add-0020af0a3278}\r\n"
  
  // see Ref 2.2.3 for packet type define:
  // chunk type contains 2 fields: Frame and PacketID.
  // Frame is 0x24 or 0xA4(rarely), different PacketID indicates different packet type.
  typedef enum {
      CHUNK_TYPE_DATA          = 0x4424,
      CHUNK_TYPE_ASF_HEADER    = 0x4824,
      CHUNK_TYPE_END           = 0x4524,
      CHUNK_TYPE_STREAM_CHANGE = 0x4324,
  } ChunkType;
  
  typedef struct MMSHContext {
      MMSContext mms;
      uint8_t location[1024];
      int request_seq;  ///< request packet sequence
      int chunk_seq;    ///< data packet sequence
  } MMSHContext;
  
  static int mmsh_close(URLContext *h)
  {
      MMSHContext *mmsh = (MMSHContext *)h->priv_data;
      MMSContext *mms   = &mmsh->mms;
      if (mms->mms_hd)
          ffurl_closep(&mms->mms_hd);
      av_freep(&mms->streams);
      av_freep(&mms->asf_header);
      return 0;
  }
  
  static ChunkType get_chunk_header(MMSHContext *mmsh, int *len)
  {
      MMSContext *mms = &mmsh->mms;
      uint8_t chunk_header[CHUNK_HEADER_LENGTH];
      uint8_t ext_header[EXT_HEADER_LENGTH];
      ChunkType chunk_type;
      int chunk_len, res, ext_header_len;
  
      res = ffurl_read_complete(mms->mms_hd, chunk_header, CHUNK_HEADER_LENGTH);
      if (res != CHUNK_HEADER_LENGTH) {
          av_log(NULL, AV_LOG_ERROR, "Read data packet header failed!\n");
          return AVERROR(EIO);
      }
      chunk_type = AV_RL16(chunk_header);
      chunk_len  = AV_RL16(chunk_header + 2);
  
      switch (chunk_type) {
      case CHUNK_TYPE_END:
      case CHUNK_TYPE_STREAM_CHANGE:
          ext_header_len = 4;
          break;
      case CHUNK_TYPE_ASF_HEADER:
      case CHUNK_TYPE_DATA:
          ext_header_len = 8;
          break;
      default:
          av_log(NULL, AV_LOG_ERROR, "Strange chunk type %d\n", chunk_type);
          return AVERROR_INVALIDDATA;
      }
  
      res = ffurl_read_complete(mms->mms_hd, ext_header, ext_header_len);
      if (res != ext_header_len) {
          av_log(NULL, AV_LOG_ERROR, "Read ext header failed!\n");
          return AVERROR(EIO);
      }
      *len = chunk_len - ext_header_len;
      if (chunk_type == CHUNK_TYPE_END || chunk_type == CHUNK_TYPE_DATA)
          mmsh->chunk_seq = AV_RL32(ext_header);
      return chunk_type;
  }
  
  static int read_data_packet(MMSHContext *mmsh, const int len)
  {
      MMSContext *mms   = &mmsh->mms;
      int res;
      if (len > sizeof(mms->in_buffer)) {
          av_log(NULL, AV_LOG_ERROR,
                 "Data packet length %d exceeds the in_buffer size %"SIZE_SPECIFIER"\n",
                 len, sizeof(mms->in_buffer));
          return AVERROR(EIO);
      }
      res = ffurl_read_complete(mms->mms_hd, mms->in_buffer, len);
      av_log(NULL, AV_LOG_TRACE, "Data packet len = %d\n", len);
      if (res != len) {
          av_log(NULL, AV_LOG_ERROR, "Read data packet failed!\n");
          return AVERROR(EIO);
      }
      if (len > mms->asf_packet_len) {
          av_log(NULL, AV_LOG_ERROR,
                 "Chunk length %d exceed packet length %d\n",len, mms->asf_packet_len);
          return AVERROR_INVALIDDATA;
      } else {
          memset(mms->in_buffer + len, 0, mms->asf_packet_len - len); // padding
      }
      mms->read_in_ptr      = mms->in_buffer;
      mms->remaining_in_len = mms->asf_packet_len;
      return 0;
  }
  
  static int get_http_header_data(MMSHContext *mmsh)
  {
      MMSContext *mms = &mmsh->mms;
      int res, len;
      ChunkType chunk_type;
  
      for (;;) {
          len = 0;
          res = chunk_type = get_chunk_header(mmsh, &len);
          if (res < 0) {
              return res;
          } else if (chunk_type == CHUNK_TYPE_ASF_HEADER){
              // get asf header and stored it
              if (!mms->header_parsed) {
                  if (mms->asf_header) {
                      if (len != mms->asf_header_size) {
                          mms->asf_header_size = len;
                          av_log(NULL, AV_LOG_TRACE, "Header len changed from %d to %d\n",
                                  mms->asf_header_size, len);
                          av_freep(&mms->asf_header);
                      }
                  }
                  mms->asf_header = av_mallocz(len);
                  if (!mms->asf_header) {
                      return AVERROR(ENOMEM);
                  }
                  mms->asf_header_size = len;
              }
              if (len > mms->asf_header_size) {
                  av_log(NULL, AV_LOG_ERROR,
                         "Asf header packet len = %d exceed the asf header buf size %d\n",
                         len, mms->asf_header_size);
                  return AVERROR(EIO);
              }
              res = ffurl_read_complete(mms->mms_hd, mms->asf_header, len);
              if (res != len) {
                  av_log(NULL, AV_LOG_ERROR,
                         "Recv asf header data len %d != expected len %d\n", res, len);
                  return AVERROR(EIO);
              }
              mms->asf_header_size = len;
              if (!mms->header_parsed) {
                  res = ff_mms_asf_header_parser(mms);
                  mms->header_parsed = 1;
                  return res;
              }
          } else if (chunk_type == CHUNK_TYPE_DATA) {
              // read data packet and do padding
              return read_data_packet(mmsh, len);
          } else {
              if (len) {
                  if (len > sizeof(mms->in_buffer)) {
                      av_log(NULL, AV_LOG_ERROR,
                             "Other packet len = %d exceed the in_buffer size %"SIZE_SPECIFIER"\n",
                             len, sizeof(mms->in_buffer));
                      return AVERROR(EIO);
                  }
                  res = ffurl_read_complete(mms->mms_hd, mms->in_buffer, len);
                  if (res != len) {
                      av_log(NULL, AV_LOG_ERROR, "Read other chunk type data failed!\n");
                      return AVERROR(EIO);
                  } else {
                      av_log(NULL, AV_LOG_TRACE, "Skip chunk type %d \n", chunk_type);
                      continue;
                  }
              }
          }
      }
  }
  
  static int mmsh_open_internal(URLContext *h, const char *uri, int flags, int timestamp, int64_t pos)
  {
      int i, port, err;
      char httpname[256], path[256], host[128];
      char *stream_selection = NULL;
      char headers[1024];
      MMSHContext *mmsh = h->priv_data;
      MMSContext *mms;
  
      mmsh->request_seq = h->is_streamed = 1;
      mms = &mmsh->mms;
      av_strlcpy(mmsh->location, uri, sizeof(mmsh->location));
  
      av_url_split(NULL, 0, NULL, 0,
          host, sizeof(host), &port, path, sizeof(path), mmsh->location);
      if (port<0)
          port = 80; // default mmsh protocol port
      ff_url_join(httpname, sizeof(httpname), "http", NULL, host, port, "%s", path);
  
      if (ffurl_alloc(&mms->mms_hd, httpname, AVIO_FLAG_READ,
                      &h->interrupt_callback) < 0) {
          return AVERROR(EIO);
      }
  
      snprintf(headers, sizeof(headers),
               "Accept: */*\r\n"
               USERAGENT
               "Host: %s:%d\r\n"
               "Pragma: no-cache,rate=1.000000,stream-time=0,"
               "stream-offset=0:0,request-context=%u,max-duration=0\r\n"
               CLIENTGUID
               "Connection: Close\r\n",
               host, port, mmsh->request_seq++);
      av_opt_set(mms->mms_hd->priv_data, "headers", headers, 0);
  
      err = ffurl_connect(mms->mms_hd, NULL);
      if (err) {
          goto fail;
      }
      err = get_http_header_data(mmsh);
      if (err) {
          av_log(NULL, AV_LOG_ERROR, "Get http header data failed!\n");
          goto fail;
      }
  
      // close the socket and then reopen it for sending the second play request.
      ffurl_close(mms->mms_hd);
      memset(headers, 0, sizeof(headers));
      if ((err = ffurl_alloc(&mms->mms_hd, httpname, AVIO_FLAG_READ,
                             &h->interrupt_callback)) < 0) {
          goto fail;
      }
      stream_selection = av_mallocz(mms->stream_num * 19 + 1);
      if (!stream_selection)
          return AVERROR(ENOMEM);
      for (i = 0; i < mms->stream_num; i++) {
          char tmp[20];
          err = snprintf(tmp, sizeof(tmp), "ffff:%d:0 ", mms->streams[i].id);
          if (err < 0)
              goto fail;
          av_strlcat(stream_selection, tmp, mms->stream_num * 19 + 1);
      }
      // send play request
      err = snprintf(headers, sizeof(headers),
                     "Accept: */*\r\n"
                     USERAGENT
                     "Host: %s:%d\r\n"
                     "Pragma: no-cache,rate=1.000000,request-context=%u\r\n"
                     "Pragma: xPlayStrm=1\r\n"
                     CLIENTGUID
                     "Pragma: stream-switch-count=%d\r\n"
                     "Pragma: stream-switch-entry=%s\r\n"
                     "Pragma: no-cache,rate=1.000000,stream-time=%u"
                     "Connection: Close\r\n",
                     host, port, mmsh->request_seq++, mms->stream_num, stream_selection, timestamp);
      av_freep(&stream_selection);
      if (err < 0) {
          av_log(NULL, AV_LOG_ERROR, "Build play request failed!\n");
          goto fail;
      }
      av_log(NULL, AV_LOG_TRACE, "out_buffer is %s", headers);
      av_opt_set(mms->mms_hd->priv_data, "headers", headers, 0);
  
      err = ffurl_connect(mms->mms_hd, NULL);
      if (err) {
            goto fail;
      }
  
      err = get_http_header_data(mmsh);
      if (err) {
          av_log(NULL, AV_LOG_ERROR, "Get http header data failed!\n");
          goto fail;
      }
  
      av_log(NULL, AV_LOG_TRACE, "Connection successfully open\n");
      return 0;
  fail:
      av_freep(&stream_selection);
      mmsh_close(h);
      av_log(NULL, AV_LOG_TRACE, "Connection failed with error %d\n", err);
      return err;
  }
  
  static int mmsh_open(URLContext *h, const char *uri, int flags)
  {
      return mmsh_open_internal(h, uri, flags, 0, 0);
  }
  
  static int handle_chunk_type(MMSHContext *mmsh)
  {
      MMSContext *mms = &mmsh->mms;
      int res, len = 0;
      ChunkType chunk_type;
      chunk_type = get_chunk_header(mmsh, &len);
  
      switch (chunk_type) {
      case CHUNK_TYPE_END:
          mmsh->chunk_seq = 0;
          av_log(NULL, AV_LOG_ERROR, "Stream ended!\n");
          return AVERROR(EIO);
      case CHUNK_TYPE_STREAM_CHANGE:
          mms->header_parsed = 0;
          if (res = get_http_header_data(mmsh)) {
              av_log(NULL, AV_LOG_ERROR,"Stream changed! Failed to get new header!\n");
              return res;
          }
          break;
      case CHUNK_TYPE_DATA:
          return read_data_packet(mmsh, len);
      default:
          av_log(NULL, AV_LOG_ERROR, "Recv other type packet %d\n", chunk_type);
          return AVERROR_INVALIDDATA;
      }
      return 0;
  }
  
  static int mmsh_read(URLContext *h, uint8_t *buf, int size)
  {
      int res = 0;
      MMSHContext *mmsh = h->priv_data;
      MMSContext *mms   = &mmsh->mms;
      do {
          if (mms->asf_header_read_size < mms->asf_header_size) {
              // copy asf header into buffer
              res = ff_mms_read_header(mms, buf, size);
          } else {
              if (!mms->remaining_in_len && (res = handle_chunk_type(mmsh)))
                  return res;
              res = ff_mms_read_data(mms, buf, size);
          }
      } while (!res);
      return res;
  }
  
  static int64_t mmsh_read_seek(URLContext *h, int stream_index,
                          int64_t timestamp, int flags)
  {
      MMSHContext *mmsh_old = h->priv_data;
      MMSHContext *mmsh     = av_mallocz(sizeof(*mmsh));
      int ret;
  
      if (!mmsh)
          return AVERROR(ENOMEM);
  
      h->priv_data = mmsh;
      ret= mmsh_open_internal(h, mmsh_old->location, 0, FFMAX(timestamp, 0), 0);
      if(ret>=0){
          h->priv_data = mmsh_old;
          mmsh_close(h);
          h->priv_data = mmsh;
          av_free(mmsh_old);
          mmsh->mms.asf_header_read_size = mmsh->mms.asf_header_size;
      }else {
          h->priv_data = mmsh_old;
          av_free(mmsh);
      }
  
      return ret;
  }
  
  static int64_t mmsh_seek(URLContext *h, int64_t pos, int whence)
  {
      MMSHContext *mmsh = h->priv_data;
      MMSContext *mms   = &mmsh->mms;
  
      if(pos == 0 && whence == SEEK_CUR)
          return mms->asf_header_read_size + mms->remaining_in_len + mmsh->chunk_seq * (int64_t)mms->asf_packet_len;
      return AVERROR(ENOSYS);
  }
  
  const URLProtocol ff_mmsh_protocol = {
      .name           = "mmsh",
      .url_open       = mmsh_open,
      .url_read       = mmsh_read,
      .url_seek       = mmsh_seek,
      .url_close      = mmsh_close,
      .url_read_seek  = mmsh_read_seek,
      .priv_data_size = sizeof(MMSHContext),
      .flags          = URL_PROTOCOL_FLAG_NETWORK,
  };
  