/* References
  * MMS protocol specification:
  *  [1]http://msdn.microsoft.com/en-us/library/cc234711(PROT.10).aspx
  * ASF specification. Revision 01.20.03.
  *  [2]http://msdn.microsoft.com/en-us/library/bb643323.aspx
  */
 

 #include "avformat.h"

 #include "mms.h"

 #include "internal.h"

 #include "avio_internal.h"

 #include "libavutil/intreadwrite.h"
 #include "libavcodec/bytestream.h"
 #include "network.h"

 #include "url.h"

 
 #define LOCAL_ADDRESS 0xc0a80081    // FIXME get and use correct local ip address.
 #define LOCAL_PORT    1037          // as above.
 /** Client to server packet types. */
 typedef enum {
     CS_PKT_INITIAL                  = 0x01,
     CS_PKT_PROTOCOL_SELECT          = 0x02,
     CS_PKT_MEDIA_FILE_REQUEST       = 0x05,
     CS_PKT_START_FROM_PKT_ID        = 0x07,
     CS_PKT_STREAM_PAUSE             = 0x09,
     CS_PKT_STREAM_CLOSE             = 0x0d,
     CS_PKT_MEDIA_HEADER_REQUEST     = 0x15,
     CS_PKT_TIMING_DATA_REQUEST      = 0x18,
     CS_PKT_USER_PASSWORD            = 0x1a,
     CS_PKT_KEEPALIVE                = 0x1b,
     CS_PKT_STREAM_ID_REQUEST        = 0x33,
 } MMSCSPacketType;
 
 /** Server to client packet types. */
 typedef enum {
     /** Control packets. */
     /*@{*/
     SC_PKT_CLIENT_ACCEPTED          = 0x01,
     SC_PKT_PROTOCOL_ACCEPTED        = 0x02,
     SC_PKT_PROTOCOL_FAILED          = 0x03,
     SC_PKT_MEDIA_PKT_FOLLOWS        = 0x05,
     SC_PKT_MEDIA_FILE_DETAILS       = 0x06,
     SC_PKT_HEADER_REQUEST_ACCEPTED  = 0x11,
     SC_PKT_TIMING_TEST_REPLY        = 0x15,
     SC_PKT_PASSWORD_REQUIRED        = 0x1a,
     SC_PKT_KEEPALIVE                = 0x1b,
     SC_PKT_STREAM_STOPPED           = 0x1e,
     SC_PKT_STREAM_CHANGING          = 0x20,
     SC_PKT_STREAM_ID_ACCEPTED       = 0x21,
     /*@}*/
 
     /** Pseudo packets. */
     /*@{*/
     SC_PKT_CANCEL                   = -1,
     SC_PKT_NO_DATA                  = -2,
     /*@}*/
 
     /** Data packets. */
     /*@{*/
     SC_PKT_ASF_HEADER               = 0x010000,// make it bigger than 0xFF in case of
     SC_PKT_ASF_MEDIA                = 0x010001,// receiving false data packets.
     /*@}*/
 } MMSSCPacketType;
 
 typedef struct {

     MMSContext  mms;
     int outgoing_packet_seq;             ///< Outgoing packet sequence number.
     char path[256];                      ///< Path of the resource being asked for.
     char host[128];                      ///< Host of the resources.
     int incoming_packet_seq;             ///< Incoming packet sequence number.
     int incoming_flags;                  ///< Incoming packet flags.
     int packet_id;                       ///< Identifier for packets in the current stream.
     unsigned int header_packet_id;       ///< default is 2.
 } MMSTContext;
 

 /** Create MMST command packet header */

 static void start_command_packet(MMSTContext *mmst, MMSCSPacketType packet_type)

 {

     MMSContext *mms    = &mmst->mms;

     mms->write_out_ptr = mms->out_buffer;
 
     bytestream_put_le32(&mms->write_out_ptr, 1); // start sequence
     bytestream_put_le32(&mms->write_out_ptr, 0xb00bface);
     bytestream_put_le32(&mms->write_out_ptr, 0); // Length starts from after the protocol type bytes
     bytestream_put_le32(&mms->write_out_ptr, MKTAG('M','M','S',' '));
     bytestream_put_le32(&mms->write_out_ptr, 0);

     bytestream_put_le32(&mms->write_out_ptr, mmst->outgoing_packet_seq++);

     bytestream_put_le64(&mms->write_out_ptr, 0); // timestamp
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le16(&mms->write_out_ptr, packet_type);
     bytestream_put_le16(&mms->write_out_ptr, 3); // direction to server
 }
 
 /** Add prefixes to MMST command packet. */
 static void insert_command_prefixes(MMSContext *mms,
         uint32_t prefix1, uint32_t prefix2)
 {
     bytestream_put_le32(&mms->write_out_ptr, prefix1); // first prefix
     bytestream_put_le32(&mms->write_out_ptr, prefix2); // second prefix
 }
 
 /** Send a prepared MMST command packet. */

 static int send_command_packet(MMSTContext *mmst)

 {

     MMSContext *mms  = &mmst->mms;

     int len= mms->write_out_ptr - mms->out_buffer;

     int exact_length = FFALIGN(len, 8);

     int first_length= exact_length - 16;
     int len8= first_length/8;
     int write_result;
 
     // update packet length fields.
     AV_WL32(mms->out_buffer + 8, first_length);
     AV_WL32(mms->out_buffer + 16, len8);
     AV_WL32(mms->out_buffer + 32, len8-2);

     memset(mms->write_out_ptr, 0, exact_length - len);

 
     // write it out.

     write_result= ffurl_write(mms->mms_hd, mms->out_buffer, exact_length);

     if(write_result != exact_length) {

         av_log(NULL, AV_LOG_ERROR,
                "Failed to write data of length %d: %d (%s)\n",
                exact_length, write_result,
                write_result < 0 ? strerror(write_result) :
                    "The server closed the connection");

         return AVERROR(EIO);

     }
 
     return 0;
 }
 

 static void mms_put_utf16(MMSContext *mms, const uint8_t *src)

 {

     AVIOContext bic;

     int size = mms->write_out_ptr - mms->out_buffer;
     int len;

     ffio_init_context(&bic, mms->write_out_ptr,

             sizeof(mms->out_buffer) - size, 1, NULL, NULL, NULL, NULL);
 

     len = avio_put_str16le(&bic, src);

     mms->write_out_ptr += len;
 }
 

 static int send_time_test_data(MMSTContext *mmst)

 {

     start_command_packet(mmst, CS_PKT_TIMING_DATA_REQUEST);

     insert_command_prefixes(&mmst->mms, 0x00f0f0f0, 0x0004000b);

     return send_command_packet(mmst);

 }
 

 static int send_protocol_select(MMSTContext *mmst)

 {
     char data_string[256];

     MMSContext *mms = &mmst->mms;

     start_command_packet(mmst, CS_PKT_PROTOCOL_SELECT);

     insert_command_prefixes(mms, 0, 0xffffffff);
     bytestream_put_le32(&mms->write_out_ptr, 0);          // maxFunnelBytes
     bytestream_put_le32(&mms->write_out_ptr, 0x00989680); // maxbitRate
     bytestream_put_le32(&mms->write_out_ptr, 2);          // funnelMode
     snprintf(data_string, sizeof(data_string), "\\\\%d.%d.%d.%d\\%s\\%d",
             (LOCAL_ADDRESS>>24)&0xff,
             (LOCAL_ADDRESS>>16)&0xff,
             (LOCAL_ADDRESS>>8)&0xff,
             LOCAL_ADDRESS&0xff,
             "TCP",                                        // or UDP
             LOCAL_PORT);
 
     mms_put_utf16(mms, data_string);

     return send_command_packet(mmst);

 }
 

 static int send_media_file_request(MMSTContext *mmst)

 {

     MMSContext *mms = &mmst->mms;
     start_command_packet(mmst, CS_PKT_MEDIA_FILE_REQUEST);

     insert_command_prefixes(mms, 1, 0xffffffff);
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0);

     mms_put_utf16(mms, mmst->path + 1); // +1 for skip "/"

     return send_command_packet(mmst);

 }
 

 static void handle_packet_stream_changing_type(MMSTContext *mmst)

 {

     MMSContext *mms = &mmst->mms;

     av_dlog(NULL, "Stream changing!\n");

 
     // 40 is the packet header size, 7 is the prefix size.

     mmst->header_packet_id= AV_RL32(mms->in_buffer + 40 + 7);

     av_dlog(NULL, "Changed header prefix to 0x%x", mmst->header_packet_id);

 }
 

 static int send_keepalive_packet(MMSTContext *mmst)

 {
     // respond to a keepalive with a keepalive...

     start_command_packet(mmst, CS_PKT_KEEPALIVE);
     insert_command_prefixes(&mmst->mms, 1, 0x100FFFF);
     return send_command_packet(mmst);

 }
 
 /** Pad media packets smaller than max_packet_size and/or adjust read position
   * after a seek. */
 static void pad_media_packet(MMSContext *mms)
 {
     if(mms->remaining_in_len<mms->asf_packet_len) {
         int padding_size = mms->asf_packet_len - mms->remaining_in_len;
         memset(mms->in_buffer + mms->remaining_in_len, 0, padding_size);
         mms->remaining_in_len += padding_size;
     }
 }
 
 /** Read incoming MMST media, header or command packet. */

 static MMSSCPacketType get_tcp_server_response(MMSTContext *mmst)

 {
     int read_result;
     MMSSCPacketType packet_type= -1;

     MMSContext *mms = &mmst->mms;

     for(;;) {

         read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer, 8);

         if (read_result != 8) {
             if(read_result < 0) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Error reading packet header: %d (%s)\n",
                        read_result, strerror(read_result));
                 packet_type = SC_PKT_CANCEL;
             } else {
                 av_log(NULL, AV_LOG_ERROR,
                        "The server closed the connection\n");
                 packet_type = SC_PKT_NO_DATA;
             }
             return packet_type;
         }
 

         // handle command packet.
         if(AV_RL32(mms->in_buffer + 4)==0xb00bface) {

             int length_remaining, hr;
 

             mmst->incoming_flags= mms->in_buffer[3];

             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer+8, 4);

             if(read_result != 4) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Reading command packet length failed: %d (%s)\n",
                        read_result,
                        read_result < 0 ? strerror(read_result) :
                            "The server closed the connection");

                 return read_result < 0 ? read_result : AVERROR(EIO);

             }

             length_remaining= AV_RL32(mms->in_buffer+8) + 4;

             av_dlog(NULL, "Length remaining is %d\n", length_remaining);

             // read the rest of the packet.
             if (length_remaining < 0
                 || length_remaining > sizeof(mms->in_buffer) - 12) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Incoming packet length %d exceeds bufsize %zu\n",
                        length_remaining, sizeof(mms->in_buffer) - 12);
                 return AVERROR_INVALIDDATA;
             }

             read_result = ffurl_read_complete(mms->mms_hd, mms->in_buffer + 12,

                                             length_remaining) ;
             if (read_result != length_remaining) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Reading pkt data (length=%d) failed: %d (%s)\n",
                        length_remaining, read_result,
                        read_result < 0 ? strerror(read_result) :
                            "The server closed the connection");

                 return read_result < 0 ? read_result : AVERROR(EIO);

             }
             packet_type= AV_RL16(mms->in_buffer+36);

             if (read_result >= 44 && (hr = AV_RL32(mms->in_buffer + 40))) {

                 av_log(NULL, AV_LOG_ERROR,

                        "Server sent a message with packet type 0x%x and error status code 0x%08x\n", packet_type, hr);

                 return AVERROR(EINVAL);

             }
         } else {
             int length_remaining;
             int packet_id_type;
             int tmp;
 
             // note we cache the first 8 bytes,
             // then fill up the buffer with the others
             tmp                       = AV_RL16(mms->in_buffer + 6);
             length_remaining          = (tmp - 8) & 0xffff;

             mmst->incoming_packet_seq = AV_RL32(mms->in_buffer);

             packet_id_type            = mms->in_buffer[4];

             mmst->incoming_flags      = mms->in_buffer[5];

 
             if (length_remaining < 0
                 || length_remaining > sizeof(mms->in_buffer) - 8) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Data length %d is invalid or too large (max=%zu)\n",
                        length_remaining, sizeof(mms->in_buffer));
                 return AVERROR_INVALIDDATA;
             }
             mms->remaining_in_len    = length_remaining;
             mms->read_in_ptr         = mms->in_buffer;

             read_result= ffurl_read_complete(mms->mms_hd, mms->in_buffer, length_remaining);

             if(read_result != length_remaining) {
                 av_log(NULL, AV_LOG_ERROR,
                        "Failed to read packet data of size %d: %d (%s)\n",
                        length_remaining, read_result,
                        read_result < 0 ? strerror(read_result) :
                            "The server closed the connection");

                 return read_result < 0 ? read_result : AVERROR(EIO);

             }
 

             // if we successfully read everything.

             if(packet_id_type == mmst->header_packet_id) {

                 packet_type = SC_PKT_ASF_HEADER;
                 // Store the asf header
                 if(!mms->header_parsed) {
                     void *p = av_realloc(mms->asf_header,
                                   mms->asf_header_size + mms->remaining_in_len);
                     if (!p) {
                         av_freep(&mms->asf_header);
                         return AVERROR(ENOMEM);
                     }
                     mms->asf_header = p;
                     memcpy(mms->asf_header + mms->asf_header_size,
                            mms->read_in_ptr, mms->remaining_in_len);
                     mms->asf_header_size += mms->remaining_in_len;
                 }
                 // 0x04 means asf header is sent in multiple packets.

                 if (mmst->incoming_flags == 0x04)

                     continue;

             } else if(packet_id_type == mmst->packet_id) {

                 packet_type = SC_PKT_ASF_MEDIA;
             } else {

                 av_dlog(NULL, "packet id type %d is old.", packet_id_type);

                 continue;
             }

         }
 
         // preprocess some packet type
         if(packet_type == SC_PKT_KEEPALIVE) {

             send_keepalive_packet(mmst);

             continue;
         } else if(packet_type == SC_PKT_STREAM_CHANGING) {

             handle_packet_stream_changing_type(mmst);

         } else if(packet_type == SC_PKT_ASF_MEDIA) {
             pad_media_packet(mms);
         }
         return packet_type;

     }
 }
 

 static int mms_safe_send_recv(MMSTContext *mmst,
                               int (*send_fun)(MMSTContext *mmst),

                               const MMSSCPacketType expect_type)
 {
     MMSSCPacketType type;
     if(send_fun) {

         int ret = send_fun(mmst);

         if (ret < 0) {

             av_dlog(NULL, "Send Packet error before expecting recv packet %d\n", expect_type);

             return ret;
         }
     }
 

     if ((type = get_tcp_server_response(mmst)) != expect_type) {

         av_log(NULL, AV_LOG_ERROR,
                "Corrupt stream (unexpected packet type 0x%x, expected 0x%x)\n",
                type, expect_type);
         return AVERROR_INVALIDDATA;

     } else {
         return 0;
     }
 }
 

 static int send_media_header_request(MMSTContext *mmst)

 {

     MMSContext *mms = &mmst->mms;
     start_command_packet(mmst, CS_PKT_MEDIA_HEADER_REQUEST);

     insert_command_prefixes(mms, 1, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0x00800000);
     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff);
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0);
 
     // the media preroll value in milliseconds?
     bytestream_put_le32(&mms->write_out_ptr, 0);
     bytestream_put_le32(&mms->write_out_ptr, 0x40AC2000);
     bytestream_put_le32(&mms->write_out_ptr, 2);
     bytestream_put_le32(&mms->write_out_ptr, 0);
 

     return send_command_packet(mmst);

 }
 
 /** Send the initial handshake. */

 static int send_startup_packet(MMSTContext *mmst)

 {
     char data_string[256];

     MMSContext *mms = &mmst->mms;

     // SubscriberName is defined in MS specification linked below.
     // The guid value can be any valid value.
     // http://download.microsoft.com/
     // download/9/5/E/95EF66AF-9026-4BB0-A41D-A4F81802D92C/%5BMS-WMSP%5D.pdf
     snprintf(data_string, sizeof(data_string),
             "NSPlayer/7.0.0.1956; {%s}; Host: %s",

             "7E667F5D-A661-495E-A512-F55686DDA178", mmst->host);

     start_command_packet(mmst, CS_PKT_INITIAL);

     insert_command_prefixes(mms, 0, 0x0004000b);
     bytestream_put_le32(&mms->write_out_ptr, 0x0003001c);
     mms_put_utf16(mms, data_string);

     return send_command_packet(mmst);

 }
 
 /** Send MMST stream selection command based on the AVStream->discard values. */

 static int send_stream_selection_request(MMSTContext *mmst)

 {
     int i;

     MMSContext *mms = &mmst->mms;

     //  send the streams we want back...

     start_command_packet(mmst, CS_PKT_STREAM_ID_REQUEST);

     bytestream_put_le32(&mms->write_out_ptr, mms->stream_num);         // stream nums
     for(i= 0; i<mms->stream_num; i++) {
         bytestream_put_le16(&mms->write_out_ptr, 0xffff);              // flags
         bytestream_put_le16(&mms->write_out_ptr, mms->streams[i].id);  // stream id
         bytestream_put_le16(&mms->write_out_ptr, 0);                   // selection
     }

     return send_command_packet(mmst);

 }
 

 static int send_close_packet(MMSTContext *mmst)

 {

     start_command_packet(mmst, CS_PKT_STREAM_CLOSE);
     insert_command_prefixes(&mmst->mms, 1, 1);

     return send_command_packet(mmst);

 }
 
 /** Close the MMSH/MMST connection */
 static int mms_close(URLContext *h)
 {

     MMSTContext *mmst = (MMSTContext *)h->priv_data;
     MMSContext *mms   = &mmst->mms;

     if(mms->mms_hd) {

         send_close_packet(mmst);

         ffurl_close(mms->mms_hd);

     }
 
     /* free all separately allocated pointers in mms */

     av_free(mms->streams);

     av_free(mms->asf_header);
 
     return 0;
 }
 

 static int send_media_packet_request(MMSTContext *mmst)

 {

     MMSContext *mms = &mmst->mms;
     start_command_packet(mmst, CS_PKT_START_FROM_PKT_ID);

     insert_command_prefixes(mms, 1, 0x0001FFFF);
     bytestream_put_le64(&mms->write_out_ptr, 0);          // seek timestamp
     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // unknown
     bytestream_put_le32(&mms->write_out_ptr, 0xffffffff); // packet offset
     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
     bytestream_put_byte(&mms->write_out_ptr, 0xff);       // max stream time limit
     bytestream_put_byte(&mms->write_out_ptr, 0x00);       // stream time limit flag
 

     mmst->packet_id++;                                     // new packet_id
     bytestream_put_le32(&mms->write_out_ptr, mmst->packet_id);
     return send_command_packet(mmst);

 }
 
 
 static void clear_stream_buffers(MMSContext *mms)
 {
     mms->remaining_in_len = 0;
     mms->read_in_ptr      = mms->in_buffer;
 }
 

 static int mms_open(URLContext *h, const char *uri, int flags)
 {

     MMSTContext *mmst = h->priv_data;

     MMSContext *mms;
     int port, err;
     char tcpname[256];
 
     h->is_streamed = 1;

     mms = &mmst->mms;

 
     // only for MMS over TCP, so set proto = NULL

     av_url_split(NULL, 0, NULL, 0,

             mmst->host, sizeof(mmst->host), &port, mmst->path,
             sizeof(mmst->path), uri);

 
     if(port<0)
         port = 1755; // defaut mms protocol port
 
     // establish tcp connection.

     ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, mmst->host, port, NULL);

     err = ffurl_open(&mms->mms_hd, tcpname, AVIO_FLAG_READ_WRITE,

                      &h->interrupt_callback, NULL);

     if (err)
         goto fail;
 

     mmst->packet_id        = 3;          // default, initial value.
     mmst->header_packet_id = 2;          // default, initial value.
     err = mms_safe_send_recv(mmst, send_startup_packet, SC_PKT_CLIENT_ACCEPTED);

     if (err)
         goto fail;

     err = mms_safe_send_recv(mmst, send_time_test_data, SC_PKT_TIMING_TEST_REPLY);

     if (err)
         goto fail;

     err = mms_safe_send_recv(mmst, send_protocol_select, SC_PKT_PROTOCOL_ACCEPTED);

     if (err)
         goto fail;

     err = mms_safe_send_recv(mmst, send_media_file_request, SC_PKT_MEDIA_FILE_DETAILS);

     if (err)
         goto fail;

     err = mms_safe_send_recv(mmst, send_media_header_request, SC_PKT_HEADER_REQUEST_ACCEPTED);

     if (err)
         goto fail;

     err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_HEADER);

     if (err)
         goto fail;

     if((mmst->incoming_flags != 0X08) && (mmst->incoming_flags != 0X0C)) {
         av_log(NULL, AV_LOG_ERROR,
                "The server does not support MMST (try MMSH or RTSP)\n");

         err = AVERROR(EINVAL);

         goto fail;

     }

     err = ff_mms_asf_header_parser(mms);

     if (err) {

         av_dlog(NULL, "asf header parsed failed!\n");

         goto fail;
     }
     mms->header_parsed = 1;
 
     if (!mms->asf_packet_len || !mms->stream_num)
         goto fail;
 

     clear_stream_buffers(mms);

     err = mms_safe_send_recv(mmst, send_stream_selection_request, SC_PKT_STREAM_ID_ACCEPTED);

     if (err)
         goto fail;
     // send media packet request

     err = mms_safe_send_recv(mmst, send_media_packet_request, SC_PKT_MEDIA_PKT_FOLLOWS);

     if (err) {
         goto fail;
     }

     av_dlog(NULL, "Leaving open (success)\n");

     return 0;
 fail:
     mms_close(h);

     av_dlog(NULL, "Leaving open (failure: %d)\n", err);

     return err;
 }
 
 /** Read ASF data through the protocol. */
 static int mms_read(URLContext *h, uint8_t *buf, int size)
 {
     /* TODO: see tcp.c:tcp_read() about a possible timeout scheme */

     MMSTContext *mmst = h->priv_data;
     MMSContext *mms   = &mmst->mms;

     int result = 0;

     do {
         if(mms->asf_header_read_size < mms->asf_header_size) {
             /* Read from ASF header buffer */

             result = ff_mms_read_header(mms, buf, size);

         } else if(mms->remaining_in_len) {
             /* Read remaining packet data to buffer.
              * the result can not be zero because remaining_in_len is positive.*/

             result = ff_mms_read_data(mms, buf, size);

         } else {
             /* Read from network */

             int err = mms_safe_send_recv(mmst, NULL, SC_PKT_ASF_MEDIA);

             if (err == 0) {
                 if(mms->remaining_in_len>mms->asf_packet_len) {
                     av_log(NULL, AV_LOG_ERROR,
                            "Incoming pktlen %d is larger than ASF pktsize %d\n",
                            mms->remaining_in_len, mms->asf_packet_len);

                     result= AVERROR(EIO);

                 } else {
                     // copy the data to the packet buffer.

                     result = ff_mms_read_data(mms, buf, size);

                     if (result == 0) {

                         av_dlog(NULL, "Read ASF media packet size is zero!\n");

                         break;
                     }
                 }
             } else {

                 av_dlog(NULL, "read packet error!\n");

                 break;
             }
         }
     } while(!result); // only return one packet.
     return result;

 }
 

 URLProtocol ff_mmst_protocol = {

     .name           = "mmst",
     .url_open       = mms_open,
     .url_read       = mms_read,
     .url_close      = mms_close,

     .priv_data_size = sizeof(MMSTContext),

     .flags          = URL_PROTOCOL_FLAG_NETWORK,

 };