Chris Conroy brought support for RTSP transfers, and with it comes 8(!) new

libcurl options for controlling what to get and how to receive posssibly
interleaved RTP data. Initial commit.

1 files changed, 753 insertions, 0 deletions

diff --git a/lib/rtsp.c b/lib/rtsp.c
new file mode 100644
index 000000000..b527fe985
--- /dev/null
+++ b/lib/rtsp.c
@@ -0,0 +1,753 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2010, 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 http://curl.haxx.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.
+ *
+ * $Id$
+ ***************************************************************************/
+
+#include "setup.h"
+
+#ifndef CURL_DISABLE_RTSP
+
+#include "urldata.h"
+#include <curl/curl.h>
+#include "transfer.h"
+#include "sendf.h"
+#include "easyif.h" /* for Curl_convert_... prototypes */
+#include "multiif.h"
+#include "http.h"
+#include "url.h"
+#include "progress.h"
+#include "rtsp.h"
+#include "rawstr.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+/* The last #include file should be: */
+#include "memdebug.h"
+
+/*
+ * TODO (general)
+ *  -incoming server requests
+ *      -server CSeq counter
+ *  -digest authentication
+ *  -connect thru proxy
+ *  -pipelining?
+ */
+
+
+static int rtsp_getsock_do(struct connectdata *conn,
+                           curl_socket_t *socks,
+                           int numsocks);
+
+/* 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 connectdata *conn,
+                           curl_socket_t *socks,
+                           int numsocks)
+{
+  /* write mode */
+  (void)numsocks; /* unused, we trust it to be at least 1 */
+  socks[0] = conn->sock[FIRSTSOCKET];
+  return GETSOCK_WRITESOCK(0);
+}
+
+static
+CURLcode rtp_client_write(struct connectdata *conn, char *ptr, size_t len);
+
+
+/*
+ * RTSP handler interface.
+ */
+const struct Curl_handler Curl_handler_rtsp = {
+  "RTSP",                               /* scheme */
+  ZERO_NULL,                            /* setup_connection */
+  Curl_rtsp,                            /* do_it */
+  Curl_rtsp_done,                       /* done */
+  ZERO_NULL,                            /* do_more */
+  Curl_rtsp_connect,                    /* connect_it */
+  ZERO_NULL,                            /* connecting */
+  ZERO_NULL,                            /* doing */
+  ZERO_NULL,                            /* proto_getsock */
+  rtsp_getsock_do,                      /* doing_getsock */
+  ZERO_NULL,                            /* perform_getsock */
+  Curl_rtsp_disconnect,                 /* disconnect */
+  PORT_RTSP,                            /* defport */
+  PROT_RTSP,                            /* protocol */
+};
+
+CURLcode Curl_rtsp_connect(struct connectdata *conn, bool *done)
+{
+  CURLcode httpStatus;
+  struct SessionHandle *data = conn->data;
+
+  httpStatus = Curl_http_connect(conn, 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;
+
+  conn->proto.rtspc.rtp_channel = -1;
+
+  return httpStatus;
+}
+
+CURLcode Curl_rtsp_disconnect(struct connectdata *conn) {
+  Curl_safefree(conn->proto.rtspc.rtp_buf);
+  return CURLE_OK;
+}
+
+
+CURLcode Curl_rtsp_done(struct connectdata *conn,
+                        CURLcode status, bool premature)
+{
+  CURLcode httpStatus;
+  struct SessionHandle *data = conn->data;
+  long CSeq_sent;
+  long CSeq_recv;
+
+  httpStatus = Curl_http_done(conn, status, premature);
+
+  /* Check the sequence numbers */
+  CSeq_sent = data->state.proto.rtsp->CSeq_sent;
+  CSeq_recv = data->state.proto.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;
+  }
+  else if (data->set.rtspreq == RTSPREQ_RECEIVE &&
+           (conn->proto.rtspc.rtp_channel == -1)) {
+    infof(data, "Got a non RTP Receive with a CSeq of %ld\n", CSeq_recv);
+    /* TODO CPC: Server -> Client logic here */
+  }
+
+  return httpStatus;
+}
+
+CURLcode Curl_rtsp(struct connectdata *conn, bool *done)
+{
+  struct SessionHandle *data = conn->data;
+  CURLcode result=CURLE_OK;
+  Curl_RtspReq rtspreq = data->set.rtspreq;
+  struct RTSP *rtsp;
+  struct HTTP *http;
+  Curl_send_buffer *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;
+
+  *done = TRUE;
+
+  Curl_reset_reqproto(conn);
+
+  if(!data->state.proto.rtsp) {
+    /* Only allocate this struct if we don't already have it! */
+
+    rtsp = calloc(sizeof(struct RTSP), 1);
+    if(!rtsp)
+      return CURLE_OUT_OF_MEMORY;
+    data->state.proto.rtsp = rtsp;
+  }
+  else {
+    rtsp = data->state.proto.rtsp;
+  }
+
+  http = &(rtsp->http_wrapper);
+  /* Assert that no one has changed the RTSP struct in an evil way */
+  DEBUGASSERT((void *)http == (void *)rtsp);
+
+  rtsp->CSeq_sent = data->state.rtsp_next_client_CSeq;
+  rtsp->CSeq_recv = 0;
+
+  /* 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.
+   **/
+  DEBUGASSERT((rtspreq > RTSPREQ_NONE && rtspreq < RTSPREQ_LAST));
+  data->set.opt_no_body = TRUE; /* most requests don't contain a body */
+  switch(rtspreq) {
+  case RTSPREQ_NONE:
+    failf(data, "Got invalid RTSP request: RTSPREQ_NONE");
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+    break;
+  case RTSPREQ_OPTIONS:
+    p_request = "OPTIONS";
+    break;
+  case RTSPREQ_DESCRIBE:
+    p_request = "DESCRIBE";
+    data->set.opt_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:
+    p_request = "GET_PARAMETER";
+    data->set.opt_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->set.opt_no_body = FALSE;
+    break;
+  case RTSPREQ_LAST:
+    failf(data, "Got invalid RTSP request: RTSPREQ_LAST");
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+    break;
+  }
+
+  if(rtspreq == RTSPREQ_RECEIVE) {
+    result = Curl_setup_transfer(conn, FIRSTSOCKET, -1, TRUE,
+                                 &http->readbytecount, -1, NULL);
+
+    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 ? p_request : "");
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+  }
+
+  /* TODO: auth? */
+  /* TODO: proxy? */
+
+  /* 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, "Transport:");
+  if(rtspreq == RTSPREQ_SETUP && !p_transport) {
+    /* New Transport: setting? */
+    if(data->set.str[STRING_RTSP_TRANSPORT]) {
+      Curl_safefree(conn->allocptr.rtsp_transport);
+
+      conn->allocptr.rtsp_transport =
+        aprintf("Transport: %s\r\n",
+                data->set.str[STRING_RTSP_TRANSPORT]);
+      if(!conn->allocptr.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 = conn->allocptr.rtsp_transport;
+  }
+
+  /* Accept Headers for DESCRIBE requests */
+  if(rtspreq == RTSPREQ_DESCRIBE) {
+    /* Accept Header */
+    p_accept = Curl_checkheaders(data, "Accept:")?
+      NULL:"Accept: application/sdp\r\n";
+
+    /* Accept-Encoding header */
+    if(!Curl_checkheaders(data, "Accept-Encoding:") &&
+       data->set.str[STRING_ENCODING]) {
+      Curl_safefree(conn->allocptr.accept_encoding);
+      conn->allocptr.accept_encoding =
+        aprintf("Accept-Encoding: %s\r\n", data->set.str[STRING_ENCODING]);
+
+      if(!conn->allocptr.accept_encoding)
+        return CURLE_OUT_OF_MEMORY;
+
+      p_accept_encoding = conn->allocptr.accept_encoding;
+    }
+  }
+
+  /* Default to text/parameters for GET_PARAMETER */
+  if(rtspreq == RTSPREQ_GET_PARAMETER) {
+    p_accept = Curl_checkheaders(data, "Accept:")?
+      NULL:"Accept: text/parameters\r\n";
+  }
+
+  /* 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, "User-Agent:") && conn->allocptr.uagent) {
+    Curl_safefree(conn->allocptr.uagent);
+    conn->allocptr.uagent = NULL;
+  }
+  else if(!Curl_checkheaders(data, "User-Agent:") &&
+          data->set.str[STRING_USERAGENT]) {
+    p_uagent = conn->allocptr.uagent;
+  }
+
+  /* Referrer */
+  Curl_safefree(conn->allocptr.ref);
+  if(data->change.referer && !Curl_checkheaders(data, "Referer:"))
+    conn->allocptr.ref = aprintf("Referer: %s\r\n", data->change.referer);
+  else
+    conn->allocptr.ref = NULL;
+
+  p_referrer = conn->allocptr.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, "Range:") && data->state.range) {
+      Curl_safefree(conn->allocptr.rangeline);
+      conn->allocptr.rangeline = aprintf("Range: %s\r\n", data->state.range);
+      p_range = conn->allocptr.rangeline;
+    }
+  }
+
+  /*
+   * Sanity check the custom headers
+   */
+  if(Curl_checkheaders(data, "CSeq:")) {
+    failf(data, "CSeq cannot be set as a custom header.");
+    return CURLE_RTSP_CSEQ_ERROR;
+  }
+  if(Curl_checkheaders(data, "Session:")) {
+    failf(data, "Session ID cannot be set as a custom header.");
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+  }
+
+  /* Initialize a dynamic send buffer */
+  req_buffer = Curl_add_buffer_init();
+
+  if(!req_buffer)
+    return CURLE_OUT_OF_MEMORY;
+
+  result =
+    Curl_add_bufferf(req_buffer,
+                     "%s %s RTSP/1.0\r\n" /* Request Stream-URI RTSP/1.0 */
+                     "CSeq: %d \r\n", /* CSeq */
+                     (p_request ? 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_add_bufferf(req_buffer, "Session: %s \r\n", p_session_id);
+    if(result)
+      return result;
+  }
+
+  /*
+   * Shared HTTP-like options
+   */
+  result = Curl_add_bufferf(req_buffer,
+                            "%s" /* transport */
+                            "%s" /* accept */
+                            "%s" /* accept-encoding */
+                            "%s" /* range */
+                            "%s" /* referrer */
+                            "%s" /* user-agent */
+                            ,
+                            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 : "");
+
+  if((rtspreq == RTSPREQ_SETUP) || (rtspreq == RTSPREQ_DESCRIBE)) {
+    result = Curl_add_timecondition(data, req_buffer);
+    if(result)
+      return result;
+  }
+
+  result = Curl_add_custom_headers(conn, req_buffer);
+  if(result)
+    return result;
+
+  if(rtspreq == RTSPREQ_ANNOUNCE || rtspreq == RTSPREQ_SET_PARAMETER) {
+    if(data->set.upload) {
+      putsize = data->set.infilesize;
+      data->set.httpreq = HTTPREQ_PUT;
+
+    }
+    else {
+      postsize = (data->set.postfieldsize != -1)?
+        data->set.postfieldsize:
+        (data->set.postfields? (curl_off_t)strlen(data->set.postfields):0);
+      data->set.httpreq = HTTPREQ_POST;
+    }
+
+    /* 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, "Content-Length:")) {
+      result = Curl_add_bufferf(req_buffer,
+                                "Content-Length: %" FORMAT_OFF_T"\r\n",
+                                (data->set.upload ? putsize : postsize));
+      if(result)
+        return result;
+    }
+
+    if(rtspreq == RTSPREQ_SET_PARAMETER) {
+      if(!Curl_checkheaders(data, "Content-Type:")) {
+        result = Curl_add_bufferf(req_buffer,
+                                  "Content-Type: text/parameters\r\n");
+      }
+      if(result)
+        return result;
+    }
+
+    if(rtspreq == RTSPREQ_ANNOUNCE) {
+      if(!Curl_checkheaders(data, "Content-Type:")) {
+        result = Curl_add_bufferf(req_buffer,
+                                  "Content-Type: application/sdp\r\n");
+      }
+    }
+
+    data->state.expect100header = FALSE; /* RTSP posts are simple/small */
+  }
+
+
+  /* RTSP never allows chunked transfer */
+  data->req.forbidchunk = TRUE;
+  /* Finish the request buffer */
+  result = Curl_add_buffer(req_buffer, "\r\n", 2);
+  if(result)
+    return result;
+
+  if(postsize > 0) {
+    result = Curl_add_buffer(req_buffer, data->set.postfields,
+                             (size_t)postsize);
+    if(result)
+      return result;
+  }
+
+  /* issue the request */
+  result = Curl_add_buffer_send(req_buffer, conn,
+                                &data->info.request_size, 0, FIRSTSOCKET);
+  if(result) {
+    failf(data, "Failed sending RTSP request");
+    return result;
+  }
+
+  result = Curl_setup_transfer(conn, FIRSTSOCKET, -1, TRUE,
+                               &http->readbytecount,
+                               putsize?FIRSTSOCKET:-1,
+                               putsize?&http->writebytecount:NULL);
+
+  if(result) {
+    failf(data, "Failed RTSP transfer");
+    return result;
+  }
+
+  /* Increment the CSeq on success */
+  data->state.rtsp_next_client_CSeq++;
+
+  if(http->writebytecount) {
+    /* if a request-body has been sent off, we make sure this progress is
+       noted properly */
+    Curl_pgrsSetUploadCounter(data, http->writebytecount);
+    if(Curl_pgrsUpdate(conn))
+      result = CURLE_ABORTED_BY_CALLBACK;
+  }
+
+  return result;
+
+  return CURLE_OK;
+
+}
+
+CURLcode Curl_rtsp_rtp_readwrite(struct SessionHandle *data,
+                                 struct connectdata *conn,
+                                 ssize_t *nread,
+                                 bool *readmore,
+                                 bool *done) {
+  struct SingleRequest *k = &data->req;
+  struct rtsp_conn *rtspc = &(conn->proto.rtspc);
+
+  char *rtp; /* moving pointer to rtp data */
+  ssize_t rtp_dataleft; /* how much data left to parse in this round */
+  char *scratch;
+  CURLcode result;
+
+  if(rtspc->rtp_buf) {
+    /* There was some leftover data the last time. Merge buffers */
+    rtspc->rtp_buf = realloc(rtspc->rtp_buf, rtspc->rtp_bufsize + *nread);
+    if(!rtspc->rtp_buf)
+      return CURLE_OUT_OF_MEMORY;
+    memcpy(rtspc->rtp_buf + rtspc->rtp_bufsize, k->str, *nread);
+    rtspc->rtp_bufsize += *nread;
+    rtp = rtspc->rtp_buf;
+    rtp_dataleft = rtspc->rtp_bufsize;
+  }
+  else {
+    /* Just parse the request buffer directly */
+    rtp = k->str;
+    rtp_dataleft = *nread;
+  }
+
+  if(rtp_dataleft == 0 || rtp[0] != '$') {
+    return  CURLE_OK;
+  }
+
+  while((rtp_dataleft > 0) &&
+        (rtp[0] == '$')) {
+    if(rtp_dataleft > 4) {
+      char channel;
+      int rtp_length;
+
+      /* Parse the header */
+      /* The channel identifier immediately follows and is 1 byte */
+      channel = rtp[1];
+      rtspc->rtp_channel = (int) channel;
+
+      /* The length is two bytes */
+      rtp_length = ntohs( *((unsigned short *)(&rtp[2])) );
+
+      if(rtp_dataleft < rtp_length + 4) {
+        /* Need more - incomplete payload*/
+        *readmore = TRUE;
+        break;
+      }
+      else {
+        /* We have the full RTP interleaved packet
+         * Write out the header but strip the leading '$' */
+        infof(data, "CPCDEBUG: RTP write channel %d rtp_length %d\n",
+              rtspc->rtp_channel, rtp_length);
+        result = rtp_client_write(conn, &rtp[1], rtp_length + 3);
+        if(result) {
+            failf(data, "Got an error writing an RTP packet");
+            *done = TRUE;
+            *readmore = FALSE;
+            return result;
+        }
+
+        /* Update progress */
+        k->bytecount += rtp_length + 4;
+        Curl_pgrsSetDownloadCounter(data, k->bytecount);
+        if(k->bytecountp)
+          *k->bytecountp = k->bytecount;
+
+        /* Move forward in the buffer */
+        rtp_dataleft -= rtp_length + 4;
+        rtp += rtp_length + 4;
+
+        if(data->set.rtspreq == RTSPREQ_RECEIVE) {
+          /* If we are in a passive receive, give control back
+           * to the app as often as we can.
+           *
+           * Otherwise, keep chugging along until we get RTSP data
+           */
+          k->keepon &= ~KEEP_RECV;
+          *done = TRUE;
+        }
+      }
+    }
+    else {
+      /* Need more - incomplete header */
+      *readmore = TRUE;
+      break;
+    }
+  }
+
+  if(*done || *readmore) {
+    if(rtp_dataleft != 0 && rtp[0] == '$') {
+      infof(data, "RTP Rewinding %zu %s %s\n", rtp_dataleft,
+            *done ? "DONE " : "",
+            *readmore ? "READMORE" : "");
+
+      /* Store the incomplete RTP packet for a "rewind" */
+      scratch = malloc(rtp_dataleft);
+      if(!scratch)
+        return CURLE_OUT_OF_MEMORY;
+      memcpy(scratch, rtp, rtp_dataleft);
+      Curl_safefree(rtspc->rtp_buf);
+      rtspc->rtp_buf = scratch;
+      rtspc->rtp_bufsize = rtp_dataleft;
+      return CURLE_OK;
+    }
+  }
+  else {
+    /* RTP followed by RTSP */
+    if(rtp_dataleft == 0) {
+      /* Need more */
+      *readmore = TRUE;
+    }
+    else {
+      /* Fix up k->str to point just after the last RTP packet */
+      k->str += *nread - rtp_dataleft;
+
+      /* rtp may point into the leftover buffer, but at this point
+       * it is somewhere in the merged data from k->str. */
+      DEBUGASSERT(k->str[0] == rtp[0]);
+
+      DEBUGASSERT(rtp_dataleft < *nread); /* sanity check */
+
+      *nread = rtp_dataleft;
+    }
+  }
+
+  /* If we get here, we have finished with the leftover/merge buffer */
+  Curl_safefree(rtspc->rtp_buf);
+  rtspc->rtp_buf = NULL;
+  rtspc->rtp_bufsize = 0;
+
+  /* TODO CPC: Could implement parsing logic for Server->Client requests
+     here */
+
+  return CURLE_OK;
+}
+
+CURLcode rtp_client_write(struct connectdata *conn, char *ptr, size_t len)
+{
+  struct SessionHandle *data = conn->data;
+  size_t wrote;
+  curl_write_callback writeit;
+
+  if(len == 0) {
+    failf (data, "Cannot write a 0 size RTP packet.");
+    return CURLE_WRITE_ERROR;
+  }
+
+  writeit = data->set.fwrite_rtp?data->set.fwrite_rtp:data->set.fwrite_func;
+  wrote = writeit(ptr, 1, len, data->set.rtp_out);
+
+  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 connectdata *conn,
+                               char *header)
+{
+  struct SessionHandle *data = conn->data;
+  long CSeq = 0;
+
+  if(checkprefix("CSeq:", header)) {
+    /* Store the received CSeq. Match is verified in rtsp_done */
+    int nc;
+    char *temp = strdup(header);
+    if(!temp)
+      return CURLE_OUT_OF_MEMORY;
+    Curl_strntoupper(temp, temp, sizeof(temp));
+    nc = sscanf(temp, "CSEQ: %ld", &CSeq);
+    free(temp);
+    if(nc == 1) {
+      data->state.proto.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;
+
+    /* Find the first non-space letter */
+    start = header + 9;
+    while(*start && ISSPACE(*start))
+      start++;
+
+    if(!start) {
+      failf(data, "Got a blank Session ID");
+    }
+    else if(data->set.str[STRING_RTSP_SESSION_ID]) {
+      /* If the Session ID is set, then compare */
+      if(strncmp(start, data->set.str[STRING_RTSP_SESSION_ID],
+                 strlen(data->set.str[STRING_RTSP_SESSION_ID]))  != 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 */
+
+      /* The session ID can be an alphanumeric or a 'safe' character
+       *
+       * RFC 2326 15.1 Base Syntax:
+       * safe =  "\$" | "-" | "_" | "." | "+"
+       * */
+      char *end = start;
+      while(*end &&
+            (ISALNUM(*end) || *end == '-' || *end == '_' || *end == '.' ||
+             *end == '+' ||
+             (*end == '\\' && *(end + 1) && *(end + 1) == '$' && (++end, 1))))
+        end++;
+
+      /* Copy the id substring into a new buffer */
+      data->set.str[STRING_RTSP_SESSION_ID] = malloc(end - start + 1);
+      memcpy(data->set.str[STRING_RTSP_SESSION_ID], start, end - start);
+      (data->set.str[STRING_RTSP_SESSION_ID])[end - start] = '\0';
+    }
+  }
+  return CURLE_OK;
+}
+
+#endif /* CURL_DISABLE_RTSP */