/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_RTSP) && !defined(USE_HYPER)

#include "urldata.h"

#include <curl/curl.h>

#include "transfer.h"

#include "sendf.h"

#include "multiif.h"

#include "http.h"

#include "url.h"

#include "progress.h"

#include "rtsp.h"

#include "strcase.h"

#include "select.h"

#include "connect.h"

#include "cfilters.h"

#include "strdup.h"

/* The last 3 #include files should be in this order */

#include "curl_printf.h"

#include "curl_memory.h"

#include "memdebug.h"

#define RTP_PKT_LENGTH(p)  ((((int)((unsigned char)((p)[2]))) << 8) | \

                             ((int)((unsigned char)((p)[3]))))

/* protocol-specific functions set up to be called by the main engine */

static CURLcode rtsp_do(struct Curl_easy *data, bool *done);

static CURLcode rtsp_done(struct Curl_easy *data, CURLcode, bool premature);

static CURLcode rtsp_connect(struct Curl_easy *data, bool *done);

static CURLcode rtsp_disconnect(struct Curl_easy *data,

                                struct connectdata *conn, bool dead);

static int rtsp_getsock_do(struct Curl_easy *data,

                           struct connectdata *conn, curl_socket_t *socks);

/*

 * Parse and write out any available RTP data.

 *

 * nread: amount of data left after k->str. will be modified if RTP

 *        data is parsed and k->str is moved up

 * readmore: whether or not the RTP parser needs more data right away

 */

static CURLcode rtsp_rtp_readwrite(struct Curl_easy *data,

                                   struct connectdata *conn,

                                   ssize_t *nread,

                                   bool *readmore);

static CURLcode rtsp_setup_connection(struct Curl_easy *data,

                                      struct connectdata *conn);

static unsigned int rtsp_conncheck(struct Curl_easy *data,

                                   struct connectdata *check,

                                   unsigned int checks_to_perform);

/* this returns the socket to wait for in the DO and DOING state for the multi

   interface and then we're always _sending_ a request and thus we wait for

   the single socket to become writable only */

static int rtsp_getsock_do(struct Curl_easy *data, struct connectdata *conn,

                           curl_socket_t *socks)

{

  /* write mode */

  (void)data;

  socks[0] = conn->sock[FIRSTSOCKET];

  return GETSOCK_WRITESOCK(0);

}

static

CURLcode rtp_client_write(struct Curl_easy *data, char *ptr, size_t len);

static

CURLcode rtsp_parse_transport(struct Curl_easy *data, char *transport);

/*

 * RTSP handler interface.

 */

const struct Curl_handler Curl_handler_rtsp = {

  "RTSP",                               /* scheme */

  rtsp_setup_connection,                /* setup_connection */

  rtsp_do,                              /* do_it */

  rtsp_done,                            /* done */

  ZERO_NULL,                            /* do_more */

  rtsp_connect,                         /* connect_it */

  ZERO_NULL,                            /* connecting */

  ZERO_NULL,                            /* doing */

  ZERO_NULL,                            /* proto_getsock */

  rtsp_getsock_do,                      /* doing_getsock */

  ZERO_NULL,                            /* domore_getsock */

  ZERO_NULL,                            /* perform_getsock */

  rtsp_disconnect,                      /* disconnect */

  rtsp_rtp_readwrite,                   /* readwrite */

  rtsp_conncheck,                       /* connection_check */

  ZERO_NULL,                            /* attach connection */

  PORT_RTSP,                            /* defport */

  CURLPROTO_RTSP,                       /* protocol */

  CURLPROTO_RTSP,                       /* family */

  PROTOPT_NONE                          /* flags */

};

#define MAX_RTP_BUFFERSIZE 1000000 /* arbitrary */

static CURLcode rtsp_setup_connection(struct Curl_easy *data,

                                      struct connectdata *conn)

{

  struct RTSP *rtsp;

  (void)conn;

  data->req.p.rtsp = rtsp = calloc(1, sizeof(struct RTSP));

  if(!rtsp)

    return CURLE_OUT_OF_MEMORY;

  Curl_dyn_init(&conn->proto.rtspc.buf, MAX_RTP_BUFFERSIZE);

  return CURLE_OK;

}

/*

 * Function to check on various aspects of a connection.

 */

static unsigned int rtsp_conncheck(struct Curl_easy *data,

                                   struct connectdata *conn,

                                   unsigned int checks_to_perform)

{

  unsigned int ret_val = CONNRESULT_NONE;

  (void)data;

  if(checks_to_perform & CONNCHECK_ISDEAD) {

    bool input_pending;

    if(!Curl_conn_is_alive(data, conn, &input_pending))

      ret_val |= CONNRESULT_DEAD;

  }

  return ret_val;

}

static CURLcode rtsp_connect(struct Curl_easy *data, bool *done)

{

  CURLcode httpStatus;

  httpStatus = Curl_http_connect(data, done);

  /* Initialize the CSeq if not already done */

  if(data->state.rtsp_next_client_CSeq == 0)

    data->state.rtsp_next_client_CSeq = 1;

  if(data->state.rtsp_next_server_CSeq == 0)

    data->state.rtsp_next_server_CSeq = 1;

  data->conn->proto.rtspc.rtp_channel = -1;

  return httpStatus;

}

static CURLcode rtsp_disconnect(struct Curl_easy *data,

                                struct connectdata *conn, bool dead)

{

  (void) dead;

  (void) data;

  Curl_dyn_free(&conn->proto.rtspc.buf);

  return CURLE_OK;

}

static CURLcode rtsp_done(struct Curl_easy *data,

                          CURLcode status, bool premature)

{

  struct RTSP *rtsp = data->req.p.rtsp;

  CURLcode httpStatus;

  /* Bypass HTTP empty-reply checks on receive */

  if(data->set.rtspreq == RTSPREQ_RECEIVE)

    premature = TRUE;

  httpStatus = Curl_http_done(data, status, premature);

  if(rtsp && !status && !httpStatus) {

    /* Check the sequence numbers */

    long CSeq_sent = rtsp->CSeq_sent;

    long CSeq_recv = rtsp->CSeq_recv;

    if((data->set.rtspreq != RTSPREQ_RECEIVE) && (CSeq_sent != CSeq_recv)) {

      failf(data,

            "The CSeq of this request %ld did not match the response %ld",

            CSeq_sent, CSeq_recv);

      return CURLE_RTSP_CSEQ_ERROR;

    }

    if(data->set.rtspreq == RTSPREQ_RECEIVE &&

       (data->conn->proto.rtspc.rtp_channel == -1)) {

      infof(data, "Got an RTP Receive with a CSeq of %ld", CSeq_recv);

    }

  }

  return httpStatus;

}

static CURLcode rtsp_do(struct Curl_easy *data, bool *done)

{

  struct connectdata *conn = data->conn;

  CURLcode result = CURLE_OK;

  Curl_RtspReq rtspreq = data->set.rtspreq;

  struct RTSP *rtsp = data->req.p.rtsp;

  struct dynbuf req_buffer;

  curl_off_t postsize = 0; /* for ANNOUNCE and SET_PARAMETER */

  curl_off_t putsize = 0; /* for ANNOUNCE and SET_PARAMETER */

  const char *p_request = NULL;

  const char *p_session_id = NULL;

  const char *p_accept = NULL;

  const char *p_accept_encoding = NULL;

  const char *p_range = NULL;

  const char *p_referrer = NULL;

  const char *p_stream_uri = NULL;

  const char *p_transport = NULL;

  const char *p_uagent = NULL;

  const char *p_proxyuserpwd = NULL;

  const char *p_userpwd = NULL;

  *done = TRUE;

  rtsp->CSeq_sent = data->state.rtsp_next_client_CSeq;

  rtsp->CSeq_recv = 0;

  /* Setup the first_* fields to allow auth details get sent

     to this origin */

  if(!data->state.first_host) {

    data->state.first_host = strdup(conn->host.name);

    if(!data->state.first_host)

      return CURLE_OUT_OF_MEMORY;

    data->state.first_remote_port = conn->remote_port;

    data->state.first_remote_protocol = conn->handler->protocol;

  }

  /* Setup the 'p_request' pointer to the proper p_request string

   * Since all RTSP requests are included here, there is no need to

   * support custom requests like HTTP.

   **/

  data->req.no_body = TRUE; /* most requests don't contain a body */

  switch(rtspreq) {

  default:

    failf(data, "Got invalid RTSP request");

    return CURLE_BAD_FUNCTION_ARGUMENT;

  case RTSPREQ_OPTIONS:

    p_request = "OPTIONS";

    break;

  case RTSPREQ_DESCRIBE:

    p_request = "DESCRIBE";

    data->req.no_body = FALSE;

    break;

  case RTSPREQ_ANNOUNCE:

    p_request = "ANNOUNCE";

    break;

  case RTSPREQ_SETUP:

    p_request = "SETUP";

    break;

  case RTSPREQ_PLAY:

    p_request = "PLAY";

    break;

  case RTSPREQ_PAUSE:

    p_request = "PAUSE";

    break;

  case RTSPREQ_TEARDOWN:

    p_request = "TEARDOWN";

    break;

  case RTSPREQ_GET_PARAMETER:

    /* GET_PARAMETER's no_body status is determined later */

    p_request = "GET_PARAMETER";

    data->req.no_body = FALSE;

    break;

  case RTSPREQ_SET_PARAMETER:

    p_request = "SET_PARAMETER";

    break;

  case RTSPREQ_RECORD:

    p_request = "RECORD";

    break;

  case RTSPREQ_RECEIVE:

    p_request = "";

    /* Treat interleaved RTP as body */

    data->req.no_body = FALSE;

    break;

  case RTSPREQ_LAST:

    failf(data, "Got invalid RTSP request: RTSPREQ_LAST");

    return CURLE_BAD_FUNCTION_ARGUMENT;

  }

  if(rtspreq == RTSPREQ_RECEIVE) {

    Curl_setup_transfer(data, FIRSTSOCKET, -1, TRUE, -1);

    return result;

  }

  p_session_id = data->set.str[STRING_RTSP_SESSION_ID];

  if(!p_session_id &&

     (rtspreq & ~(RTSPREQ_OPTIONS | RTSPREQ_DESCRIBE | RTSPREQ_SETUP))) {

    failf(data, "Refusing to issue an RTSP request [%s] without a session ID.",

          p_request);

    return CURLE_BAD_FUNCTION_ARGUMENT;

  }

  /* Stream URI. Default to server '*' if not specified */

  if(data->set.str[STRING_RTSP_STREAM_URI]) {

    p_stream_uri = data->set.str[STRING_RTSP_STREAM_URI];

  }

  else {

    p_stream_uri = "*";

  }

  /* Transport Header for SETUP requests */

  p_transport = Curl_checkheaders(data, STRCONST("Transport"));

  if(rtspreq == RTSPREQ_SETUP && !p_transport) {

    /* New Transport: setting? */

    if(data->set.str[STRING_RTSP_TRANSPORT]) {

      Curl_safefree(data->state.aptr.rtsp_transport);

      data->state.aptr.rtsp_transport =

        aprintf("Transport: %s\r\n",

                data->set.str[STRING_RTSP_TRANSPORT]);

      if(!data->state.aptr.rtsp_transport)

        return CURLE_OUT_OF_MEMORY;

    }

    else {

      failf(data,

            "Refusing to issue an RTSP SETUP without a Transport: header.");

      return CURLE_BAD_FUNCTION_ARGUMENT;

    }

    p_transport = data->state.aptr.rtsp_transport;

  }

  /* Accept Headers for DESCRIBE requests */

  if(rtspreq == RTSPREQ_DESCRIBE) {

    /* Accept Header */

    p_accept = Curl_checkheaders(data, STRCONST("Accept"))?

      NULL:"Accept: application/sdp\r\n";

    /* Accept-Encoding header */

    if(!Curl_checkheaders(data, STRCONST("Accept-Encoding")) &&

       data->set.str[STRING_ENCODING]) {

      Curl_safefree(data->state.aptr.accept_encoding);

      data->state.aptr.accept_encoding =

        aprintf("Accept-Encoding: %s\r\n", data->set.str[STRING_ENCODING]);

      if(!data->state.aptr.accept_encoding)

        return CURLE_OUT_OF_MEMORY;

      p_accept_encoding = data->state.aptr.accept_encoding;

    }

  }

  /* The User-Agent string might have been allocated in url.c already, because

     it might have been used in the proxy connect, but if we have got a header

     with the user-agent string specified, we erase the previously made string

     here. */

  if(Curl_checkheaders(data, STRCONST("User-Agent")) &&

     data->state.aptr.uagent) {

    Curl_safefree(data->state.aptr.uagent);

  }

  else if(!Curl_checkheaders(data, STRCONST("User-Agent")) &&

          data->set.str[STRING_USERAGENT]) {

    p_uagent = data->state.aptr.uagent;

  }

  /* setup the authentication headers */

  result = Curl_http_output_auth(data, conn, p_request, HTTPREQ_GET,

                                 p_stream_uri, FALSE);

  if(result)

    return result;

  p_proxyuserpwd = data->state.aptr.proxyuserpwd;

  p_userpwd = data->state.aptr.userpwd;

  /* Referrer */

  Curl_safefree(data->state.aptr.ref);

  if(data->state.referer && !Curl_checkheaders(data, STRCONST("Referer")))

    data->state.aptr.ref = aprintf("Referer: %s\r\n", data->state.referer);

  p_referrer = data->state.aptr.ref;

  /*

   * Range Header

   * Only applies to PLAY, PAUSE, RECORD

   *

   * Go ahead and use the Range stuff supplied for HTTP

   */

  if(data->state.use_range &&

     (rtspreq  & (RTSPREQ_PLAY | RTSPREQ_PAUSE | RTSPREQ_RECORD))) {

    /* Check to see if there is a range set in the custom headers */

    if(!Curl_checkheaders(data, STRCONST("Range")) && data->state.range) {

      Curl_safefree(data->state.aptr.rangeline);

      data->state.aptr.rangeline = aprintf("Range: %s\r\n", data->state.range);

      p_range = data->state.aptr.rangeline;

    }

  }

  /*

   * Sanity check the custom headers

   */

  if(Curl_checkheaders(data, STRCONST("CSeq"))) {

    failf(data, "CSeq cannot be set as a custom header.");

    return CURLE_RTSP_CSEQ_ERROR;

  }

  if(Curl_checkheaders(data, STRCONST("Session"))) {

    failf(data, "Session ID cannot be set as a custom header.");

    return CURLE_BAD_FUNCTION_ARGUMENT;

  }

  /* Initialize a dynamic send buffer */

  Curl_dyn_init(&req_buffer, DYN_RTSP_REQ_HEADER);

  result =

    Curl_dyn_addf(&req_buffer,

                  "%s %s RTSP/1.0\r\n" /* Request Stream-URI RTSP/1.0 */

                  "CSeq: %ld\r\n", /* CSeq */

                  p_request, p_stream_uri, rtsp->CSeq_sent);

  if(result)

    return result;

  /*

   * Rather than do a normal alloc line, keep the session_id unformatted

   * to make comparison easier

   */

  if(p_session_id) {

    result = Curl_dyn_addf(&req_buffer, "Session: %s\r\n", p_session_id);

    if(result)

      return result;

  }

  /*

   * Shared HTTP-like options

   */

  result = Curl_dyn_addf(&req_buffer,

                         "%s" /* transport */

                         "%s" /* accept */

                         "%s" /* accept-encoding */

                         "%s" /* range */

                         "%s" /* referrer */

                         "%s" /* user-agent */

                         "%s" /* proxyuserpwd */

                         "%s" /* userpwd */

                         ,

                         p_transport ? p_transport : "",

                         p_accept ? p_accept : "",

                         p_accept_encoding ? p_accept_encoding : "",

                         p_range ? p_range : "",

                         p_referrer ? p_referrer : "",

                         p_uagent ? p_uagent : "",

                         p_proxyuserpwd ? p_proxyuserpwd : "",

                         p_userpwd ? p_userpwd : "");

  /*

   * Free userpwd now --- cannot reuse this for Negotiate and possibly NTLM

   * with basic and digest, it will be freed anyway by the next request

   */

  Curl_safefree(data->state.aptr.userpwd);

  if(result)

    return result;

  if((rtspreq == RTSPREQ_SETUP) || (rtspreq == RTSPREQ_DESCRIBE)) {

    result = Curl_add_timecondition(data, &req_buffer);

    if(result)

      return result;

  }

  result = Curl_add_custom_headers(data, FALSE, &req_buffer);

  if(result)

    return result;

  if(rtspreq == RTSPREQ_ANNOUNCE ||

     rtspreq == RTSPREQ_SET_PARAMETER ||

     rtspreq == RTSPREQ_GET_PARAMETER) {

    if(data->state.upload) {

      putsize = data->state.infilesize;

      data->state.httpreq = HTTPREQ_PUT;

    }

    else {

      postsize = (data->state.infilesize != -1)?

        data->state.infilesize:

        (data->set.postfields? (curl_off_t)strlen(data->set.postfields):0);

      data->state.httpreq = HTTPREQ_POST;

    }

    if(putsize > 0 || postsize > 0) {

      /* As stated in the http comments, it is probably not wise to

       * actually set a custom Content-Length in the headers */

      if(!Curl_checkheaders(data, STRCONST("Content-Length"))) {

        result =

          Curl_dyn_addf(&req_buffer,

                        "Content-Length: %" CURL_FORMAT_CURL_OFF_T"\r\n",

                        (data->state.upload ? putsize : postsize));

        if(result)

          return result;

      }

      if(rtspreq == RTSPREQ_SET_PARAMETER ||

         rtspreq == RTSPREQ_GET_PARAMETER) {

        if(!Curl_checkheaders(data, STRCONST("Content-Type"))) {

          result = Curl_dyn_addn(&req_buffer,

                                 STRCONST("Content-Type: "

                                          "text/parameters\r\n"));

          if(result)

            return result;

        }

      }

      if(rtspreq == RTSPREQ_ANNOUNCE) {

        if(!Curl_checkheaders(data, STRCONST("Content-Type"))) {

          result = Curl_dyn_addn(&req_buffer,

                                 STRCONST("Content-Type: "

                                          "application/sdp\r\n"));

          if(result)

            return result;

        }

      }

      data->state.expect100header = FALSE; /* RTSP posts are simple/small */

    }

    else if(rtspreq == RTSPREQ_GET_PARAMETER) {

      /* Check for an empty GET_PARAMETER (heartbeat) request */

      data->state.httpreq = HTTPREQ_HEAD;

      data->req.no_body = TRUE;

    }

  }

  /* RTSP never allows chunked transfer */

  data->req.forbidchunk = TRUE;

  /* Finish the request buffer */

  result = Curl_dyn_addn(&req_buffer, STRCONST("\r\n"));

  if(result)

    return result;

  if(postsize > 0) {

    result = Curl_dyn_addn(&req_buffer, data->set.postfields,

                           (size_t)postsize);

    if(result)

      return result;

  }

  /* issue the request */

  result = Curl_buffer_send(&req_buffer, data, data->req.p.http,

                            &data->info.request_size, 0, FIRSTSOCKET);

  if(result) {

    failf(data, "Failed sending RTSP request");

    return result;

  }

  Curl_setup_transfer(data, FIRSTSOCKET, -1, TRUE, putsize?FIRSTSOCKET:-1);

  /* Increment the CSeq on success */

  data->state.rtsp_next_client_CSeq++;

  if(data->req.writebytecount) {

    /* if a request-body has been sent off, we make sure this progress is

       noted properly */

    Curl_pgrsSetUploadCounter(data, data->req.writebytecount);

    if(Curl_pgrsUpdate(data))

      result = CURLE_ABORTED_BY_CALLBACK;

  }

  return result;

}

static CURLcode rtsp_rtp_readwrite(struct Curl_easy *data,

                                   struct connectdata *conn,

                                   ssize_t *nread,

                                   bool *readmore) {

  struct SingleRequest *k = &data->req;

  struct rtsp_conn *rtspc = &(conn->proto.rtspc);

  unsigned char *rtp_channel_mask = data->state.rtp_channel_mask;

  char *rtp; /* moving pointer to rtp data */

  ssize_t rtp_dataleft; /* how much data left to parse in this round */

  CURLcode result;

  bool interleaved = false;

  size_t skip_size = 0;

  if(Curl_dyn_len(&rtspc->buf)) {

    /* There was some leftover data the last time. Append new buffers */

    if(Curl_dyn_addn(&rtspc->buf, k->str, *nread))

      return CURLE_OUT_OF_MEMORY;

    rtp = Curl_dyn_ptr(&rtspc->buf);

    rtp_dataleft = Curl_dyn_len(&rtspc->buf);

  }

  else {

    /* Just parse the request buffer directly */

    rtp = k->str;

    rtp_dataleft = *nread;

  }

  while(rtp_dataleft > 0) {

    if(rtp[0] == '$') {

      if(rtp_dataleft > 4) {

        unsigned char rtp_channel;

        int rtp_length;

        int idx;

        int off;

        /* Parse the header */

        /* The channel identifier immediately follows and is 1 byte */

        rtp_channel = (unsigned char)rtp[1];

        idx = rtp_channel / 8;

        off = rtp_channel % 8;

        if(!(rtp_channel_mask[idx] & (1 << off))) {

          /* invalid channel number, maybe not an RTP packet */

          rtp++;

          rtp_dataleft--;

          skip_size++;

          continue;

        }

        if(skip_size > 0) {

          DEBUGF(infof(data, "Skip the malformed interleaved data %lu "

                       "bytes", skip_size));

        }

        skip_size = 0;

        rtspc->rtp_channel = rtp_channel;

        /* The length is two bytes */

        rtp_length = RTP_PKT_LENGTH(rtp);

        if(rtp_dataleft < rtp_length + 4) {

          /* Need more - incomplete payload */

          *readmore = TRUE;

          break;

        }

        interleaved = true;

        /* We have the full RTP interleaved packet

         * Write out the header including the leading '$' */

        DEBUGF(infof(data, "RTP write channel %d rtp_length %d",

                     rtspc->rtp_channel, rtp_length));

        result = rtp_client_write(data, &rtp[0], rtp_length + 4);

        if(result) {

          *readmore = FALSE;

          return result;

        }

        /* Move forward in the buffer */

        rtp_dataleft -= rtp_length + 4;

        rtp += rtp_length + 4;

        if(data->set.rtspreq == RTSPREQ_RECEIVE) {

          /* If we are in a passive receive, give control back

           * to the app as often as we can.

           */

          k->keepon &= ~KEEP_RECV;

        }

      }

      else {

        /* Need more - incomplete header */

        *readmore = TRUE;

        break;

      }

    }

    else {

      /* If the following data begins with 'RTSP/', which might be an RTSP

         message, we should stop skipping the data. */

      /* If `k-> headerline> 0 && !interleaved` is true, we are maybe in the

         middle of an RTSP message. It is difficult to determine this, so we

         stop skipping. */

      size_t prefix_len = (rtp_dataleft < 5) ? rtp_dataleft : 5;

      if((k->headerline > 0 && !interleaved) ||

         strncmp(rtp, "RTSP/", prefix_len) == 0) {

        if(skip_size > 0) {

          DEBUGF(infof(data, "Skip the malformed interleaved data %lu "

                       "bytes", skip_size));

        }

        break; /* maybe is an RTSP message */

      }

      /* Skip incorrect data util the next RTP packet or RTSP message */

      do {

        rtp++;

        rtp_dataleft--;

        skip_size++;

      } while(rtp_dataleft > 0 && rtp[0] != '$' && rtp[0] != 'R');

    }

  }

  if(rtp_dataleft && rtp[0] == '$') {

    DEBUGF(infof(data, "RTP Rewinding %zd %s", rtp_dataleft,

                 *readmore ? "(READMORE)" : ""));

    /* Store the incomplete RTP packet for a "rewind" */

    if(!Curl_dyn_len(&rtspc->buf)) {

      /* nothing was stored, add this data */

      if(Curl_dyn_addn(&rtspc->buf, rtp, rtp_dataleft))

        return CURLE_OUT_OF_MEMORY;

    }

    else {

      /* keep the remainder */

      Curl_dyn_tail(&rtspc->buf, rtp_dataleft);

    }

    /* As far as the transfer is concerned, this data is consumed */

    *nread = 0;

    return CURLE_OK;

  }

  /* Fix up k->str to point just after the last RTP packet */

  k->str += *nread - rtp_dataleft;

  *nread = rtp_dataleft;

  /* If we get here, we have finished with the leftover/merge buffer */

  Curl_dyn_free(&rtspc->buf);

  return CURLE_OK;

}

static

CURLcode rtp_client_write(struct Curl_easy *data, char *ptr, size_t len)

{

  size_t wrote;

  curl_write_callback writeit;

  void *user_ptr;

  if(len == 0) {

    failf(data, "Cannot write a 0 size RTP packet.");

    return CURLE_WRITE_ERROR;

  }

  /* If the user has configured CURLOPT_INTERLEAVEFUNCTION then use that

     function and any configured CURLOPT_INTERLEAVEDATA to write out the RTP

     data. Otherwise, use the CURLOPT_WRITEFUNCTION with the CURLOPT_WRITEDATA

     pointer to write out the RTP data. */

  if(data->set.fwrite_rtp) {

    writeit = data->set.fwrite_rtp;

    user_ptr = data->set.rtp_out;

  }

  else {

    writeit = data->set.fwrite_func;

    user_ptr = data->set.out;

  }

  Curl_set_in_callback(data, true);

  wrote = writeit(ptr, 1, len, user_ptr);

  Curl_set_in_callback(data, false);

  if(CURL_WRITEFUNC_PAUSE == wrote) {

    failf(data, "Cannot pause RTP");

    return CURLE_WRITE_ERROR;

  }

  if(wrote != len) {

    failf(data, "Failed writing RTP data");

    return CURLE_WRITE_ERROR;

  }

  return CURLE_OK;

}

CURLcode Curl_rtsp_parseheader(struct Curl_easy *data, char *header)

{

  if(checkprefix("CSeq:", header)) {

    long CSeq = 0;

    char *endp;

    char *p = &header[5];

    while(ISBLANK(*p))

      p++;

    CSeq = strtol(p, &endp, 10);

    if(p != endp) {

      struct RTSP *rtsp = data->req.p.rtsp;

      rtsp->CSeq_recv = CSeq; /* mark the request */

      data->state.rtsp_CSeq_recv = CSeq; /* update the handle */

    }

    else {

      failf(data, "Unable to read the CSeq header: [%s]", header);

      return CURLE_RTSP_CSEQ_ERROR;

    }

  }

  else if(checkprefix("Session:", header)) {

    char *start;

    char *end;

    size_t idlen;

    /* Find the first non-space letter */

    start = header + 8;

    while(*start && ISBLANK(*start))

      start++;

    if(!*start) {

      failf(data, "Got a blank Session ID");

      return CURLE_RTSP_SESSION_ERROR;

    }

    /* Find the end of Session ID

     *

     * Allow any non whitespace content, up to the field separator or end of

     * line. RFC 2326 isn't 100% clear on the session ID and for example

     * gstreamer does url-encoded session ID's not covered by the standard.

     */

    end = start;

    while(*end && *end != ';' && !ISSPACE(*end))

      end++;

    idlen = end - start;

    if(data->set.str[STRING_RTSP_SESSION_ID]) {

      /* If the Session ID is set, then compare */

      if(strlen(data->set.str[STRING_RTSP_SESSION_ID]) != idlen ||

         strncmp(start, data->set.str[STRING_RTSP_SESSION_ID], idlen) != 0) {

        failf(data, "Got RTSP Session ID Line [%s], but wanted ID [%s]",

              start, data->set.str[STRING_RTSP_SESSION_ID]);

        return CURLE_RTSP_SESSION_ERROR;

      }

    }

    else {

      /* If the Session ID is not set, and we find it in a response, then set

       * it.

       */

      /* Copy the id substring into a new buffer */

      data->set.str[STRING_RTSP_SESSION_ID] = malloc(idlen + 1);

      if(!data->set.str[STRING_RTSP_SESSION_ID])

        return CURLE_OUT_OF_MEMORY;

      memcpy(data->set.str[STRING_RTSP_SESSION_ID], start, idlen);

      (data->set.str[STRING_RTSP_SESSION_ID])[idlen] = '\0';

    }

  }

  else if(checkprefix("Transport:", header)) {

    CURLcode result;

    result = rtsp_parse_transport(data, header + 10);

    if(result)

      return result;

  }

  return CURLE_OK;

}

static

CURLcode rtsp_parse_transport(struct Curl_easy *data, char *transport)

{

  /* If we receive multiple Transport response-headers, the linterleaved

     channels of each response header is recorded and used together for

     subsequent data validity checks.*/

  /* e.g.: ' RTP/AVP/TCP;unicast;interleaved=5-6' */

  char *start;

  char *end;

  start = transport;

  while(start && *start) {

    while(*start && ISBLANK(*start) )

      start++;

    end = strchr(start, ';');

    if(checkprefix("interleaved=", start)) {

      long chan1, chan2, chan;

      char *endp;

      char *p = start + 12;

      chan1 = strtol(p, &endp, 10);

      if(p != endp && chan1 >= 0 && chan1 <= 255) {

        unsigned char *rtp_channel_mask = data->state.rtp_channel_mask;

        chan2 = chan1;

        if(*endp == '-') {

          p = endp + 1;

          chan2 = strtol(p, &endp, 10);

          if(p == endp || chan2 < 0 || chan2 > 255) {

            infof(data, "Unable to read the interleaved parameter from "

                  "Transport header: [%s]", transport);

            chan2 = chan1;

          }

        }

        for(chan = chan1; chan <= chan2; chan++) {