liveMedia/RTSPClient.cpp

/**********
This library 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 3 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)

This library 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 this library; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
**********/
// "liveMedia"
// Copyright (c) 1996-2020 Live Networks, Inc.  All rights reserved.
// A generic RTSP client
// Implementation

#include "RTSPClient.hh"
#include "RTSPCommon.hh"
#include "Base64.hh"
#include "Locale.hh"
#include <GroupsockHelper.hh>
#include "ourMD5.hh"

RTSPClient* RTSPClient::createNew(UsageEnvironment& env, char const* rtspURL,
				  int verbosityLevel,
				  char const* applicationName,
				  portNumBits tunnelOverHTTPPortNum,
				  int socketNumToServer) {
  return new RTSPClient(env, rtspURL,
			verbosityLevel, applicationName, tunnelOverHTTPPortNum, socketNumToServer);
}

unsigned RTSPClient::sendDescribeCommand(responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "DESCRIBE", responseHandler));
}

unsigned RTSPClient::sendOptionsCommand(responseHandler* responseHandler, Authenticator* authenticator) {
  if (authenticator != NULL) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "OPTIONS", responseHandler));
}

unsigned RTSPClient::sendAnnounceCommand(char const* sdpDescription, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "ANNOUNCE", responseHandler, NULL, NULL, False, 0.0, 0.0, 0.0, sdpDescription));
}

unsigned RTSPClient::sendSetupCommand(MediaSubsession& subsession, responseHandler* responseHandler,
                                      Boolean streamOutgoing, Boolean streamUsingTCP, Boolean forceMulticastOnUnspecified,
				      Authenticator* authenticator) {
  if (fTunnelOverHTTPPortNum != 0) streamUsingTCP = True; // RTSP-over-HTTP tunneling uses TCP (by definition)
  // However, if we're using a TLS connection, streaming over TCP doesn't work, so disable it:
  if (fTLS.isNeeded) streamUsingTCP = False;
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;

  u_int32_t booleanFlags = 0;
  if (streamUsingTCP) booleanFlags |= 0x1;
  if (streamOutgoing) booleanFlags |= 0x2;
  if (forceMulticastOnUnspecified) booleanFlags |= 0x4;
  return sendRequest(new RequestRecord(++fCSeq, "SETUP", responseHandler, NULL, &subsession, booleanFlags));
}

unsigned RTSPClient::sendPlayCommand(MediaSession& session, responseHandler* responseHandler,
                                     double start, double end, float scale,
                                     Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  sendDummyUDPPackets(session); // hack to improve NAT traversal
  return sendRequest(new RequestRecord(++fCSeq, "PLAY", responseHandler, &session, NULL, 0, start, end, scale));
}

unsigned RTSPClient::sendPlayCommand(MediaSubsession& subsession, responseHandler* responseHandler,
                                     double start, double end, float scale,
                                     Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  sendDummyUDPPackets(subsession); // hack to improve NAT traversal
  return sendRequest(new RequestRecord(++fCSeq, "PLAY", responseHandler, NULL, &subsession, 0, start, end, scale));
}

unsigned RTSPClient::sendPlayCommand(MediaSession& session, responseHandler* responseHandler,
				     char const* absStartTime, char const* absEndTime, float scale,
                                     Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  sendDummyUDPPackets(session); // hack to improve NAT traversal
  return sendRequest(new RequestRecord(++fCSeq, responseHandler, absStartTime, absEndTime, scale, &session, NULL));
}

unsigned RTSPClient::sendPlayCommand(MediaSubsession& subsession, responseHandler* responseHandler,
				     char const* absStartTime, char const* absEndTime, float scale,
                                     Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  sendDummyUDPPackets(subsession); // hack to improve NAT traversal
  return sendRequest(new RequestRecord(++fCSeq, responseHandler, absStartTime, absEndTime, scale, NULL, &subsession));
}

unsigned RTSPClient::sendPauseCommand(MediaSession& session, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "PAUSE", responseHandler, &session));
}

unsigned RTSPClient::sendPauseCommand(MediaSubsession& subsession, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "PAUSE", responseHandler, NULL, &subsession));
}

unsigned RTSPClient::sendRecordCommand(MediaSession& session, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "RECORD", responseHandler, &session));
}

unsigned RTSPClient::sendRecordCommand(MediaSubsession& subsession, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "RECORD", responseHandler, NULL, &subsession));
}

unsigned RTSPClient::sendTeardownCommand(MediaSession& session, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "TEARDOWN", responseHandler, &session));
}

unsigned RTSPClient::sendTeardownCommand(MediaSubsession& subsession, responseHandler* responseHandler, Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  return sendRequest(new RequestRecord(++fCSeq, "TEARDOWN", responseHandler, NULL, &subsession));
}

unsigned RTSPClient::sendSetParameterCommand(MediaSession& session, responseHandler* responseHandler,
                                             char const* parameterName, char const* parameterValue,
                                             Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;
  char* paramString = new char[strlen(parameterName) + strlen(parameterValue) + 10];
  sprintf(paramString, "%s: %s\r\n", parameterName, parameterValue);
  unsigned result = sendRequest(new RequestRecord(++fCSeq, "SET_PARAMETER", responseHandler, &session, NULL, False, 0.0, 0.0, 0.0, paramString));
  delete[] paramString;
  return result;
}

unsigned RTSPClient::sendGetParameterCommand(MediaSession& session, responseHandler* responseHandler, char const* parameterName,
                                             Authenticator* authenticator) {
  if (fCurrentAuthenticator < authenticator) fCurrentAuthenticator = *authenticator;

  // We assume that:
  //    parameterName is NULL or "" means: Send no body in the request.
  //    parameterName is non-empty means: Send "<parameterName>\r\n" as the request body.  
  unsigned parameterNameLen = parameterName == NULL ? 0 : strlen(parameterName);
  char* paramString = new char[parameterNameLen + 3]; // the 3 is for \r\n + the '\0' byte
  if (parameterName == NULL || parameterName[0] == '\0') {
    paramString[0] = '\0';
  } else {
    sprintf(paramString, "%s\r\n", parameterName);
  }
  unsigned result = sendRequest(new RequestRecord(++fCSeq, "GET_PARAMETER", responseHandler, &session, NULL, False, 0.0, 0.0, 0.0, paramString));
  delete[] paramString;
  return result;
}

void RTSPClient::sendDummyUDPPackets(MediaSession& session, unsigned numDummyPackets) {
  MediaSubsessionIterator iter(session);
  MediaSubsession* subsession;

  while ((subsession = iter.next()) != NULL) {
    sendDummyUDPPackets(*subsession, numDummyPackets);
  }
}

void RTSPClient::sendDummyUDPPackets(MediaSubsession& subsession, unsigned numDummyPackets) {
  // Hack: To increase the likelihood of UDP packets from the server reaching us,
  // if we're behind a NAT, send a few 'dummy' UDP packets to the server now.
  // (We do this on both our RTP port and our RTCP port.)
  Groupsock* gs1 = NULL; Groupsock* gs2 = NULL;
  if (subsession.rtpSource() != NULL) gs1 = subsession.rtpSource()->RTPgs();
  if (subsession.rtcpInstance() != NULL) gs2 = subsession.rtcpInstance()->RTCPgs();
  u_int32_t const dummy = 0xFEEDFACE;
  for (unsigned i = 0; i < numDummyPackets; ++i) {
    if (gs1 != NULL) gs1->output(envir(), (unsigned char*)&dummy, sizeof dummy);
    if (gs2 != NULL) gs2->output(envir(), (unsigned char*)&dummy, sizeof dummy);
  }
}

void RTSPClient::setSpeed(MediaSession& session, float speed) { 
  // Optionally set download speed for session to be used later on PLAY command:
  // The user should call this function after the MediaSession is instantiated, but before the
  // first "sendPlayCommand()" is called.
  session.speed() = speed;
  MediaSubsessionIterator iter(session);
  MediaSubsession* subsession;

  while ((subsession = iter.next()) != NULL) {
    subsession->speed() = speed;
  }
}

Boolean RTSPClient::changeResponseHandler(unsigned cseq, responseHandler* newResponseHandler) { 
  // Look for the matching request record in each of our 'pending requests' queues:
  RequestRecord* request;
  if ((request = fRequestsAwaitingConnection.findByCSeq(cseq)) != NULL
      || (request = fRequestsAwaitingHTTPTunneling.findByCSeq(cseq)) != NULL
      || (request = fRequestsAwaitingResponse.findByCSeq(cseq)) != NULL) {
    request->handler() = newResponseHandler;
    return True;
  }

  return False;
}

Boolean RTSPClient::lookupByName(UsageEnvironment& env,
				 char const* instanceName,
				 RTSPClient*& resultClient) {
  resultClient = NULL; // unless we succeed

  Medium* medium;
  if (!Medium::lookupByName(env, instanceName, medium)) return False;

  if (!medium->isRTSPClient()) {
    env.setResultMsg(instanceName, " is not a RTSP client");
    return False;
  }

  resultClient = (RTSPClient*)medium;
  return True;
}

static void copyUsernameOrPasswordStringFromURL(char* dest, char const* src, unsigned len) {
  // Normally, we just copy from the source to the destination.  However, if the source contains
  // %-encoded characters, then we decode them while doing the copy:
  while (len > 0) {
    int nBefore = 0;
    int nAfter = 0;
    
    if (*src == '%' && len >= 3 && sscanf(src+1, "%n%2hhx%n", &nBefore, dest, &nAfter) == 1) {
      unsigned codeSize = nAfter - nBefore; // should be 1 or 2

      ++dest;
      src += (1 + codeSize);
      len -= (1 + codeSize);
    } else {
      *dest++ = *src++;
      --len;
    }
  }
  *dest = '\0';
}

Boolean RTSPClient::parseRTSPURL(char const* url,
				 char*& username, char*& password,
				 NetAddress& address,
				 portNumBits& portNum,
				 char const** urlSuffix) {
  do {
    // Parse the URL as "rtsp://[<username>[:<password>]@]<server-address-or-name>[:<port>][/<stream-name>]" (or "rtsps://...")
    char const* prefix1 = "rtsp://";
    unsigned const prefix1Length = 7;
    char const* prefix2 = "rtsps://";
    unsigned const prefix2Length = 8;

    portNumBits defaultPortNumber;
    char const* from;
    if (_strncasecmp(url, prefix1, prefix1Length) == 0) {
      defaultPortNumber = 554;
      from = &url[prefix1Length];
    } else if (_strncasecmp(url, prefix2, prefix2Length) == 0) {
      useTLS();
      defaultPortNumber = 322;
      from = &url[prefix2Length];
    } else {
      envir().setResultMsg("URL does not begin with \"rtsp://\" or \"rtsps://\"");
      break;
    }

    unsigned const parseBufferSize = 100;
    char parseBuffer[parseBufferSize];

    // Check whether "<username>[:<password>]@" occurs next.
    // We do this by checking whether '@' appears before the end of the URL, or before the first '/'.
    username = password = NULL; // default return values
    char const* colonPasswordStart = NULL;
    char const* lastAtPtr = NULL;
    for (char const* p = from; *p != '\0' && *p != '/'; ++p) {
      if (*p == ':' && colonPasswordStart == NULL) {
	colonPasswordStart = p;
      } else if (*p == '@') {
	lastAtPtr = p;
      }
    }
    if (lastAtPtr != NULL) {      
      // We found <username> (and perhaps <password>).  Copy them into newly-allocated result strings:
      if (colonPasswordStart == NULL || colonPasswordStart > lastAtPtr) colonPasswordStart = lastAtPtr;

      char const* usernameStart = from;
      unsigned usernameLen = colonPasswordStart - usernameStart;
      username = new char[usernameLen + 1] ; // allow for the trailing '\0'
      copyUsernameOrPasswordStringFromURL(username, usernameStart, usernameLen);

      char const* passwordStart = colonPasswordStart;
      if (passwordStart < lastAtPtr) ++passwordStart; // skip over the ':'
      unsigned passwordLen = lastAtPtr - passwordStart;
      password = new char[passwordLen + 1]; // allow for the trailing '\0'
      copyUsernameOrPasswordStringFromURL(password, passwordStart, passwordLen);

      from = lastAtPtr + 1; // skip over the '@'
    }

    // Next, parse <server-address-or-name>
    char* to = &parseBuffer[0];
    unsigned i;
    for (i = 0; i < parseBufferSize; ++i) {
      if (*from == '\0' || *from == ':' || *from == '/') {
	// We've completed parsing the address
	*to = '\0';
	break;
      }
      *to++ = *from++;
    }
    if (i == parseBufferSize) {
      envir().setResultMsg("URL is too long");
      break;
    }

    NetAddressList addresses(parseBuffer);
    if (addresses.numAddresses() == 0) {
      envir().setResultMsg("Failed to find network address for \"",
		       parseBuffer, "\"");
      break;
    }
    address = *(addresses.firstAddress());

    portNum = defaultPortNumber; // unless it's specified explicitly in the URL
    char nextChar = *from;
    if (nextChar == ':') {
      int portNumInt;
      if (sscanf(++from, "%d", &portNumInt) != 1) {
	envir().setResultMsg("No port number follows ':'");
	break;
      }
      if (portNumInt < 1 || portNumInt > 65535) {
	envir().setResultMsg("Bad port number");
	break;
      }
      portNum = (portNumBits)portNumInt;
      while (*from >= '0' && *from <= '9') ++from; // skip over port number
    }

    // The remainder of the URL is the suffix:
    if (urlSuffix != NULL) *urlSuffix = from;

    return True;
  } while (0);

  // An error occurred in the parsing:
  return False;
}

void RTSPClient::setUserAgentString(char const* userAgentName) {
  if (userAgentName == NULL) return;

  // Change the existing user agent header string:
  char const* const formatStr = "User-Agent: %s\r\n";
  unsigned const headerSize = strlen(formatStr) + strlen(userAgentName);
  delete[] fUserAgentHeaderStr;
  fUserAgentHeaderStr = new char[headerSize];
  sprintf(fUserAgentHeaderStr, formatStr, userAgentName);
  fUserAgentHeaderStrLen = strlen(fUserAgentHeaderStr);
}

unsigned RTSPClient::responseBufferSize = 20000; // default value; you can reassign this in your application if you need to

RTSPClient::RTSPClient(UsageEnvironment& env, char const* rtspURL,
		       int verbosityLevel, char const* applicationName,
		       portNumBits tunnelOverHTTPPortNum, int socketNumToServer)
  : Medium(env),
    desiredMaxIncomingPacketSize(0), fVerbosityLevel(verbosityLevel), fCSeq(1),
    fAllowBasicAuthentication(True), fServerAddress(0),
    fTunnelOverHTTPPortNum(tunnelOverHTTPPortNum),
    fUserAgentHeaderStr(NULL), fUserAgentHeaderStrLen(0),
    fInputSocketNum(-1), fOutputSocketNum(-1), fBaseURL(NULL), fTCPStreamIdCount(0),
    fLastSessionId(NULL), fSessionTimeoutParameter(0), fSessionCookieCounter(0), fHTTPTunnelingConnectionIsPending(False),
    fTLS(*this) {
  setBaseURL(rtspURL);

  fResponseBuffer = new char[responseBufferSize+1];
  resetResponseBuffer();

  if (socketNumToServer >= 0) {
    // This socket number is (assumed to be) already connected to the server.
    // Use it, and arrange to handle responses to requests sent on it:
    fInputSocketNum = fOutputSocketNum = socketNumToServer;
    env.taskScheduler().setBackgroundHandling(fInputSocketNum, SOCKET_READABLE|SOCKET_EXCEPTION,
						  (TaskScheduler::BackgroundHandlerProc*)&incomingDataHandler, this);
  }

  // Set the "User-Agent:" header to use in each request:
  char const* const libName = "LIVE555 Streaming Media v";
  char const* const libVersionStr = LIVEMEDIA_LIBRARY_VERSION_STRING;
  char const* libPrefix; char const* libSuffix;
  if (applicationName == NULL || applicationName[0] == '\0') {
    applicationName = libPrefix = libSuffix = "";
  } else {
    libPrefix = " (";
    libSuffix = ")";
  }
  unsigned userAgentNameSize
    = strlen(applicationName) + strlen(libPrefix) + strlen(libName) + strlen(libVersionStr) + strlen(libSuffix) + 1;
  char* userAgentName = new char[userAgentNameSize];
  sprintf(userAgentName, "%s%s%s%s%s", applicationName, libPrefix, libName, libVersionStr, libSuffix);
  setUserAgentString(userAgentName);
  delete[] userAgentName;
}

RTSPClient::~RTSPClient() {
  reset();

  delete[] fResponseBuffer;
  delete[] fUserAgentHeaderStr;
}

void RTSPClient::reset() {
  resetTCPSockets();
  resetResponseBuffer();
  fRequestsAwaitingConnection.reset();
  fRequestsAwaitingHTTPTunneling.reset();
  fRequestsAwaitingResponse.reset();
  fServerAddress = 0;

  setBaseURL(NULL);

  fCurrentAuthenticator.reset();

  delete[] fLastSessionId; fLastSessionId = NULL;
}

void RTSPClient::setBaseURL(char const* url) {
  delete[] fBaseURL; fBaseURL = strDup(url);
}

int RTSPClient::grabSocket() {
  int inputSocket = fInputSocketNum;
  RTPInterface::clearServerRequestAlternativeByteHandler(envir(), fInputSocketNum); // in case we were receiving RTP-over-TCP
  fInputSocketNum = -1;

  return inputSocket;
}

unsigned RTSPClient::sendRequest(RequestRecord* request) {
  char* cmd = NULL;
  do {
    Boolean connectionIsPending = False;
    if (!fRequestsAwaitingConnection.isEmpty()) {
      // A connection is currently pending (with at least one enqueued request).  Enqueue this request also:
      connectionIsPending = True;
    } else if (fInputSocketNum < 0) { // we need to open a connection
      int connectResult = openConnection();
      if (connectResult < 0) break; // an error occurred
      else if (connectResult == 0) {
	// A connection is pending
        connectionIsPending = True;
      } // else the connection succeeded.  Continue sending the command.
    }
    if (connectionIsPending) {
      fRequestsAwaitingConnection.enqueue(request);
      return request->cseq();
    }

    // If requested (and we're not already doing it, or have done it), set up the special protocol for tunneling RTSP-over-HTTP:
    if (fTunnelOverHTTPPortNum != 0 && strcmp(request->commandName(), "GET") != 0 && fOutputSocketNum == fInputSocketNum) {
      if (!setupHTTPTunneling1()) break;
      fRequestsAwaitingHTTPTunneling.enqueue(request);
      return request->cseq();
    }

    // Construct and send the command:

    // First, construct command-specific headers that we need:

    char* cmdURL = fBaseURL; // by default
    Boolean cmdURLWasAllocated = False;

    char const* protocolStr = "RTSP/1.0"; // by default

    char* extraHeaders = (char*)""; // by default
    Boolean extraHeadersWereAllocated = False; 

    char* contentLengthHeader = (char*)""; // by default
    Boolean contentLengthHeaderWasAllocated = False;

    if (!setRequestFields(request,
			  cmdURL, cmdURLWasAllocated,
			  protocolStr,
			  extraHeaders, extraHeadersWereAllocated)) {
      break;
    }

    char const* contentStr = request->contentStr(); // by default
    if (contentStr == NULL) contentStr = "";
    unsigned contentStrLen = strlen(contentStr);
    if (contentStrLen > 0) {
      char const* contentLengthHeaderFmt =
	"Content-Length: %d\r\n";
      unsigned contentLengthHeaderSize = strlen(contentLengthHeaderFmt)
	+ 20 /* max int len */;
      contentLengthHeader = new char[contentLengthHeaderSize];
      sprintf(contentLengthHeader, contentLengthHeaderFmt, contentStrLen);
      contentLengthHeaderWasAllocated = True;
    }

    char* authenticatorStr = createAuthenticatorString(request->commandName(), fBaseURL);

    char const* const cmdFmt =
      "%s %s %s\r\n"
      "CSeq: %d\r\n"
      "%s"
      "%s"
      "%s"
      "%s"
      "\r\n"
      "%s";
    unsigned cmdSize = strlen(cmdFmt)
      + strlen(request->commandName()) + strlen(cmdURL) + strlen(protocolStr)
      + 20 /* max int len */
      + strlen(authenticatorStr)
      + fUserAgentHeaderStrLen
      + strlen(extraHeaders)
      + strlen(contentLengthHeader)
      + contentStrLen;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    request->commandName(), cmdURL, protocolStr,
	    request->cseq(),
	    authenticatorStr,
	    fUserAgentHeaderStr,
            extraHeaders,
	    contentLengthHeader,
	    contentStr);
    delete[] authenticatorStr;
    if (cmdURLWasAllocated) delete[] cmdURL;
    if (extraHeadersWereAllocated) delete[] extraHeaders;
    if (contentLengthHeaderWasAllocated) delete[] contentLengthHeader;

    if (fVerbosityLevel >= 1) envir() << "Sending request: " << cmd << "\n";

    if (fTunnelOverHTTPPortNum != 0 && strcmp(request->commandName(), "GET") != 0 && strcmp(request->commandName(), "POST") != 0) {
      // When we're tunneling RTSP-over-HTTP, we Base-64-encode the request before we send it.
      // (However, we don't do this for the HTTP "GET" and "POST" commands that we use to set up the tunnel.)
      char* origCmd = cmd;
      cmd = base64Encode(origCmd, strlen(cmd));
      if (fVerbosityLevel >= 1) envir() << "\tThe request was base-64 encoded to: " << cmd << "\n\n";
      delete[] origCmd;
    }

    if (write(cmd, strlen(cmd)) < 0) {
      char const* errFmt = "%s write() failed: ";
      unsigned const errLength = strlen(errFmt) + strlen(request->commandName());
      char* err = new char[errLength];
      sprintf(err, errFmt, request->commandName());
      envir().setResultErrMsg(err);
      delete[] err;
      break;
    }

    // The command send succeeded, so enqueue the request record, so that its response (when it comes) can be handled.
    // However, note that we do not expect a response to a POST command with RTSP-over-HTTP, so don't enqueue that.
    int cseq = request->cseq();

    if (fTunnelOverHTTPPortNum == 0 || strcmp(request->commandName(), "POST") != 0) {
      fRequestsAwaitingResponse.enqueue(request);
    } else {
      delete request;
    }

    delete[] cmd;
    return cseq;
  } while (0);

  // An error occurred, so call the response handler immediately (indicating the error):
  delete[] cmd;
  handleRequestError(request);
  delete request;
  return 0;
}

static char* createSessionString(char const* sessionId) {
  char* sessionStr;
  if (sessionId != NULL) {
    sessionStr = new char[20+strlen(sessionId)];
    sprintf(sessionStr, "Session: %s\r\n", sessionId);
  } else {
    sessionStr = strDup("");
  }
  return sessionStr;
}

// Add support for faster download thru "speed:" option on PLAY
static char* createSpeedString(float speed) {
  char buf[100];
  if (speed == 1.0f ) {
    // This is the default value; we don't need a "Speed:" header:
    buf[0] = '\0';
  } else {
    sprintf(buf, "Speed: %.3f\r\n",speed);
  }

  return strDup(buf);
}

static char* createScaleString(float scale, float currentScale) {
  char buf[100];
  if (scale == 1.0f && currentScale == 1.0f) {
    // This is the default value; we don't need a "Scale:" header:
    buf[0] = '\0';
  } else {
    Locale l("C", Numeric);
    sprintf(buf, "Scale: %f\r\n", scale);
  }

  return strDup(buf);
}

static char* createRangeString(double start, double end, char const* absStartTime, char const* absEndTime) {
  char buf[100];

  if (absStartTime != NULL) {
    // Create a "Range:" header that specifies 'absolute' time values:

    if (absEndTime == NULL) {
      // There's no end time:
      snprintf(buf, sizeof buf, "Range: clock=%s-\r\n", absStartTime);
    } else {
      // There's both a start and an end time; include them both in the "Range:" hdr
      snprintf(buf, sizeof buf, "Range: clock=%s-%s\r\n", absStartTime, absEndTime);
    }
  } else {
    // Create a "Range:" header that specifies relative (i.e., NPT) time values:

    if (start < 0) {
      // We're resuming from a PAUSE; there's no "Range:" header at all
      buf[0] = '\0';
    } else if (end < 0) {
      // There's no end time:
      Locale l("C", Numeric);
      sprintf(buf, "Range: npt=%.3f-\r\n", start);
    } else {
      // There's both a start and an end time; include them both in the "Range:" hdr
      Locale l("C", Numeric);
      sprintf(buf, "Range: npt=%.3f-%.3f\r\n", start, end);
    }
  }

  return strDup(buf);
}

Boolean RTSPClient::setRequestFields(RequestRecord* request,
				     char*& cmdURL, Boolean& cmdURLWasAllocated,
				     char const*& protocolStr,
				     char*& extraHeaders, Boolean& extraHeadersWereAllocated
				     ) {
  // Set various fields that will appear in our outgoing request, depending upon the particular command that we are sending.

  if (strcmp(request->commandName(), "DESCRIBE") == 0) {
    extraHeaders = (char*)"Accept: application/sdp\r\n";
  } else if (strcmp(request->commandName(), "OPTIONS") == 0) {
    // If we're currently part of a session, create a "Session:" header (in case the server wants this to indicate
    // client 'liveness); this makes up our 'extra headers':
    extraHeaders = createSessionString(fLastSessionId);
    extraHeadersWereAllocated = True;
  } else if (strcmp(request->commandName(), "ANNOUNCE") == 0) {
    extraHeaders = (char*)"Content-Type: application/sdp\r\n";
  } else if (strcmp(request->commandName(), "SETUP") == 0) {
    MediaSubsession& subsession = *request->subsession();
    Boolean streamUsingTCP = (request->booleanFlags()&0x1) != 0;
    Boolean streamOutgoing = (request->booleanFlags()&0x2) != 0;
    Boolean forceMulticastOnUnspecified = (request->booleanFlags()&0x4) != 0;
    
    char const *prefix, *separator, *suffix;
    constructSubsessionURL(subsession, prefix, separator, suffix);
    
    char const* transportFmt;
    if (strcmp(subsession.protocolName(), "RTP") == 0) {
      transportFmt = "Transport: RTP/AVP%s%s%s=%d-%d\r\n";
    } else if (strcmp(subsession.protocolName(), "SRTP") == 0) {
      transportFmt = "Transport: RTP/SAVP%s%s%s=%d-%d\r\n";
    } else { // "UDP"
      suffix = "";
      transportFmt = "Transport: RAW/RAW/UDP%s%s%s=%d-%d\r\n";
    }
    
    cmdURL = new char[strlen(prefix) + strlen(separator) + strlen(suffix) + 1];
    cmdURLWasAllocated = True;
    sprintf(cmdURL, "%s%s%s", prefix, separator, suffix);
    
    // Construct a "Transport:" header.
    char const* transportTypeStr;
    char const* modeStr = streamOutgoing ? ";mode=receive" : "";
    // Note: I think the above is nonstandard, but DSS wants it this way
    char const* portTypeStr;
    portNumBits rtpNumber, rtcpNumber;
    if (streamUsingTCP) { // streaming over the RTSP connection
      transportTypeStr = "/TCP;unicast";
      portTypeStr = ";interleaved";
      rtpNumber = fTCPStreamIdCount++;
      rtcpNumber = fTCPStreamIdCount++;
    } else { // normal RTP streaming
      unsigned connectionAddress = subsession.connectionEndpointAddress();
      Boolean requestMulticastStreaming
	= IsMulticastAddress(connectionAddress) || (connectionAddress == 0 && forceMulticastOnUnspecified);
      transportTypeStr = requestMulticastStreaming ? ";multicast" : ";unicast";
      portTypeStr = requestMulticastStreaming ? ";port" : ";client_port";
      rtpNumber = subsession.clientPortNum();
      if (rtpNumber == 0) {
	envir().setResultMsg("Client port number unknown\n");
	delete[] cmdURL;
	return False;
      }
      rtcpNumber = subsession.rtcpIsMuxed() ? rtpNumber : rtpNumber + 1;
    }
    unsigned transportSize = strlen(transportFmt)
      + strlen(transportTypeStr) + strlen(modeStr) + strlen(portTypeStr) + 2*5 /* max port len */;
    char* transportStr = new char[transportSize];
    sprintf(transportStr, transportFmt,
	    transportTypeStr, modeStr, portTypeStr, rtpNumber, rtcpNumber);
    
    // When sending more than one "SETUP" request, include a "Session:" header in the 2nd and later commands:
    char* sessionStr = createSessionString(fLastSessionId);
    
    // Optionally include a "Blocksize:" string:
    char* blocksizeStr = createBlocksizeString(streamUsingTCP);

    // Optionally include a "KeyMgmt:" string:
    char* keyMgmtStr = createKeyMgmtString(cmdURL, subsession);

    // The "Transport:", "Session:" (if present), "Blocksize:" (if present), and "KeyMgmt:" (if present)
    // headers make up the 'extra headers':
    extraHeaders = new char[transportSize + strlen(sessionStr) + strlen(blocksizeStr) + strlen(keyMgmtStr) + 1];
    extraHeadersWereAllocated = True;
    sprintf(extraHeaders, "%s%s%s%s", transportStr, sessionStr, blocksizeStr, keyMgmtStr);
    delete[] transportStr; delete[] sessionStr; delete[] blocksizeStr; delete[] keyMgmtStr;
  } else if (strcmp(request->commandName(), "GET") == 0 || strcmp(request->commandName(), "POST") == 0) {
    // We will be sending a HTTP (not a RTSP) request.
    // Begin by re-parsing our RTSP URL, to get the stream name (which we'll use as our 'cmdURL'
    // in the subsequent request), and the server address (which we'll use in a "Host:" header):
    char* username;
    char* password;
    NetAddress destAddress;
    portNumBits urlPortNum;
    if (!parseRTSPURL(fBaseURL, username, password, destAddress, urlPortNum, (char const**)&cmdURL)) return False;
    if (cmdURL[0] == '\0') cmdURL = (char*)"/";
    delete[] username;
    delete[] password;
    netAddressBits serverAddress = *(netAddressBits*)(destAddress.data());
    AddressString serverAddressString(serverAddress);
    
    protocolStr = "HTTP/1.1";
    
    if (strcmp(request->commandName(), "GET") == 0) {
      // Create a 'session cookie' string, using MD5:
      struct {
	struct timeval timestamp;
	unsigned counter;
      } seedData;
      gettimeofday(&seedData.timestamp, NULL);
      seedData.counter = ++fSessionCookieCounter;
      our_MD5Data((unsigned char*)(&seedData), sizeof seedData, fSessionCookie);
      // DSS seems to require that the 'session cookie' string be 22 bytes long:
      fSessionCookie[23] = '\0';
      
      char const* const extraHeadersFmt =
	"Host: %s\r\n"
	"x-sessioncookie: %s\r\n"
	"Accept: application/x-rtsp-tunnelled\r\n"
	"Pragma: no-cache\r\n"
	"Cache-Control: no-cache\r\n";
      unsigned extraHeadersSize = strlen(extraHeadersFmt)
	+ strlen(serverAddressString.val())
	+ strlen(fSessionCookie);
      extraHeaders = new char[extraHeadersSize];
      extraHeadersWereAllocated = True;
      sprintf(extraHeaders, extraHeadersFmt,
	      serverAddressString.val(),
	      fSessionCookie);
    } else { // "POST"
      char const* const extraHeadersFmt =
	"Host: %s\r\n"
	"x-sessioncookie: %s\r\n"
	"Content-Type: application/x-rtsp-tunnelled\r\n"
	"Pragma: no-cache\r\n"
	"Cache-Control: no-cache\r\n"
	"Content-Length: 32767\r\n"
	"Expires: Sun, 9 Jan 1972 00:00:00 GMT\r\n";
      unsigned extraHeadersSize = strlen(extraHeadersFmt)
	+ strlen(serverAddressString.val())
	+ strlen(fSessionCookie);
      extraHeaders = new char[extraHeadersSize];
      extraHeadersWereAllocated = True;
      sprintf(extraHeaders, extraHeadersFmt,
	      serverAddressString.val(),
	      fSessionCookie);
    }
  } else { // "PLAY", "PAUSE", "TEARDOWN", "RECORD", "SET_PARAMETER", "GET_PARAMETER"
    // First, make sure that we have a RTSP session in progress
    if (fLastSessionId == NULL) {
      envir().setResultMsg("No RTSP session is currently in progress\n");
      return False;
    }
    
    char const* sessionId;
    float originalScale;
    if (request->session() != NULL) {
      // Session-level operation
      cmdURL = (char*)sessionURL(*request->session());
      
      sessionId = fLastSessionId;
      originalScale = request->session()->scale();
    } else {
      // Media-level operation
      char const *prefix, *separator, *suffix;
      constructSubsessionURL(*request->subsession(), prefix, separator, suffix);
      cmdURL = new char[strlen(prefix) + strlen(separator) + strlen(suffix) + 1];
      cmdURLWasAllocated = True;
      sprintf(cmdURL, "%s%s%s", prefix, separator, suffix);
      
      sessionId = request->subsession()->sessionId();
      originalScale = request->subsession()->scale();
    }
    
    if (strcmp(request->commandName(), "PLAY") == 0) {
      // Create possible "Session:", "Scale:", "Speed:", and "Range:" headers;
      // these make up the 'extra headers':
      char* sessionStr = createSessionString(sessionId);
      char* scaleStr = createScaleString(request->scale(), originalScale);
      float speed = request->session() != NULL ? request->session()->speed() : request->subsession()->speed();
      char* speedStr = createSpeedString(speed);
      char* rangeStr = createRangeString(request->start(), request->end(), request->absStartTime(), request->absEndTime());
      extraHeaders = new char[strlen(sessionStr) + strlen(scaleStr) + strlen(speedStr) + strlen(rangeStr) + 1];
      extraHeadersWereAllocated = True;
      sprintf(extraHeaders, "%s%s%s%s", sessionStr, scaleStr, speedStr, rangeStr);
      delete[] sessionStr; delete[] scaleStr; delete[] speedStr; delete[] rangeStr;
    } else {
      // Create a "Session:" header; this makes up our 'extra headers':
      extraHeaders = createSessionString(sessionId);
      extraHeadersWereAllocated = True;
    }
  }

  return True;
}

Boolean RTSPClient::isRTSPClient() const {
  return True;
}

void RTSPClient::resetTCPSockets() {
  if (fInputSocketNum >= 0) {
    RTPInterface::clearServerRequestAlternativeByteHandler(envir(), fInputSocketNum); // in case we were receiving RTP-over-TCP
    envir().taskScheduler().disableBackgroundHandling(fInputSocketNum);
    ::closeSocket(fInputSocketNum);
    if (fOutputSocketNum != fInputSocketNum) {
      envir().taskScheduler().disableBackgroundHandling(fOutputSocketNum);
      ::closeSocket(fOutputSocketNum);
    }
  }
  fInputSocketNum = fOutputSocketNum = -1;
}

void RTSPClient::resetResponseBuffer() {
  fResponseBytesAlreadySeen = 0;
  fResponseBufferBytesLeft = responseBufferSize;
}

int RTSPClient::openConnection() {
  do {
    // Set up a connection to the server.  Begin by parsing the URL:
    
    char* username;
    char* password;
    NetAddress destAddress;
    portNumBits urlPortNum;
    char const* urlSuffix;
    if (!parseRTSPURL(fBaseURL, username, password, destAddress, urlPortNum, &urlSuffix)) break;
    portNumBits destPortNum = fTunnelOverHTTPPortNum == 0 ? urlPortNum : fTunnelOverHTTPPortNum;
    if (destPortNum == 322) useTLS(); // port 322 is a special case: "rtsps"

    if (username != NULL || password != NULL) {
      fCurrentAuthenticator.setUsernameAndPassword(username, password);
      delete[] username;
      delete[] password;
    }
    
    // We don't yet have a TCP socket (or we used to have one, but it got closed).  Set it up now.
    fInputSocketNum = setupStreamSocket(envir(), 0);
    if (fInputSocketNum < 0) break;
    ignoreSigPipeOnSocket(fInputSocketNum); // so that servers on the same host that get killed don't also kill us
    if (fOutputSocketNum < 0) fOutputSocketNum = fInputSocketNum;
    envir() << "Created new TCP socket " << fInputSocketNum << " for connection\n";
      
    // Connect to the remote endpoint:
    fServerAddress = *(netAddressBits*)(destAddress.data());
    int connectResult = connectToServer(fInputSocketNum, destPortNum);
    if (connectResult < 0) break;
    else if (connectResult > 0) {
      if (fTLS.isNeeded) {
	// We need to complete an additional TLS connection:
	connectResult = fTLS.connect(fInputSocketNum);
	if (connectResult < 0) break;
	if (connectResult > 0 && fVerbosityLevel >= 1) envir() << "...TLS connection completed\n";
      }

      if (connectResult > 0 && fVerbosityLevel >= 1) envir() << "...local connection opened\n";
    }

    return connectResult;
  } while (0);
  
  resetTCPSockets();
  return -1;
}

int RTSPClient::connectToServer(int socketNum, portNumBits remotePortNum) {
  MAKE_SOCKADDR_IN(remoteName, fServerAddress, htons(remotePortNum));
  if (fVerbosityLevel >= 1) {
    envir() << "Connecting to " << AddressString(remoteName).val() << ", port " << remotePortNum << " on socket " << socketNum << "...\n";
  }
  if (connect(socketNum, (struct sockaddr*) &remoteName, sizeof remoteName) != 0) {
    int const err = envir().getErrno();
    if (err == EINPROGRESS || err == EWOULDBLOCK) {
      // The connection is pending; we'll need to handle it later.  Wait for our socket to be 'writable', or have an exception.
      envir().taskScheduler().setBackgroundHandling(socketNum, SOCKET_WRITABLE|SOCKET_EXCEPTION,
						    (TaskScheduler::BackgroundHandlerProc*)&connectionHandler, this);
      return 0;
    }
    envir().setResultErrMsg("connect() failed: ");
    if (fVerbosityLevel >= 1) envir() << "..." << envir().getResultMsg() << "\n";
    return -1;
  }

  // The connection succeeded.  Arrange to handle responses to requests sent on it:
  envir().taskScheduler().setBackgroundHandling(fInputSocketNum, SOCKET_READABLE|SOCKET_EXCEPTION,
						(TaskScheduler::BackgroundHandlerProc*)&incomingDataHandler, this);

  return 1;
}

char* RTSPClient::createAuthenticatorString(char const* cmd, char const* url) {
  Authenticator& auth = fCurrentAuthenticator; // alias, for brevity
  if (auth.realm() != NULL && auth.username() != NULL && auth.password() != NULL) {
    // We have a filled-in authenticator, so use it:
    char* authenticatorStr;
    if (auth.nonce() != NULL) { // Digest authentication
      char const* const authFmt =
	"Authorization: Digest username=\"%s\", realm=\"%s\", "
	"nonce=\"%s\", uri=\"%s\", response=\"%s\"\r\n";
      char const* response = auth.computeDigestResponse(cmd, url);
      unsigned authBufSize = strlen(authFmt)
	+ strlen(auth.username()) + strlen(auth.realm())
	+ strlen(auth.nonce()) + strlen(url) + strlen(response);
      authenticatorStr = new char[authBufSize];
      sprintf(authenticatorStr, authFmt,
	      auth.username(), auth.realm(),
	      auth.nonce(), url, response);
      auth.reclaimDigestResponse(response);
    } else { // Basic authentication
      char const* const authFmt = "Authorization: Basic %s\r\n";

      unsigned usernamePasswordLength = strlen(auth.username()) + 1 + strlen(auth.password());
      char* usernamePassword = new char[usernamePasswordLength+1];
      sprintf(usernamePassword, "%s:%s", auth.username(), auth.password());

      char* response = base64Encode(usernamePassword, usernamePasswordLength);
      unsigned const authBufSize = strlen(authFmt) + strlen(response) + 1;
      authenticatorStr = new char[authBufSize];
      sprintf(authenticatorStr, authFmt, response);
      delete[] response; delete[] usernamePassword;
    }

    return authenticatorStr;
  }

  // We don't have a (filled-in) authenticator.
  return strDup("");
}

char* RTSPClient::createBlocksizeString(Boolean streamUsingTCP) {
  char* blocksizeStr;
  u_int16_t maxPacketSize = desiredMaxIncomingPacketSize;

  // Allow for the RTP header (if streaming over TCP)
  // or the IP/UDP/RTP headers (if streaming over UDP):
  u_int16_t const headerAllowance = streamUsingTCP ? 12 : 50/*conservative*/;
  if (maxPacketSize < headerAllowance) {
    maxPacketSize = 0;
  } else {
    maxPacketSize -= headerAllowance;
  }

  if (maxPacketSize > 0) {
    blocksizeStr = new char[25]; // more than enough space
    sprintf(blocksizeStr, "Blocksize: %u\r\n", maxPacketSize);
  } else {
    blocksizeStr = strDup("");
  }
  return blocksizeStr;
}

char* RTSPClient::createKeyMgmtString(char const* url, MediaSubsession const& subsession) {
  char* keyMgmtStr;
  MIKEYState* mikeyState;
  u_int8_t* mikeyMessage;
  unsigned mikeyMessageSize;

  if ((mikeyState = subsession.getMIKEYState()) == NULL ||
      (mikeyMessage = mikeyState->generateMessage(mikeyMessageSize)) == NULL) {
    keyMgmtStr = strDup("");
  } else {
    char const* keyMgmtFmt = "KeyMgmt: prot=mikey; uri=\"%s\"; data=\"%s\"\r\n";
    char* base64EncodedData = base64Encode((char*)mikeyMessage, mikeyMessageSize);
    unsigned keyMgmtSize = strlen(keyMgmtFmt)
      + strlen(url) + strlen(base64EncodedData);
    keyMgmtStr = new char[keyMgmtSize];
    sprintf(keyMgmtStr, keyMgmtFmt,
	    url, base64EncodedData);
    delete[] base64EncodedData;
  }

  return keyMgmtStr;
}

void RTSPClient::handleRequestError(RequestRecord* request) {
  int resultCode = -envir().getErrno();
  if (resultCode == 0) {
    // Choose some generic error code instead:
#if defined(__WIN32__) || defined(_WIN32) || defined(_QNX4)
    resultCode = -WSAENOTCONN;
#else
    resultCode = -ENOTCONN;
#endif
  }
  if (request->handler() != NULL) (*request->handler())(this, resultCode, strDup(envir().getResultMsg()));
}

Boolean RTSPClient
::parseResponseCode(char const* line, unsigned& responseCode, char const*& responseString) {
  if (sscanf(line, "RTSP/%*s%u", &responseCode) != 1 &&
      sscanf(line, "HTTP/%*s%u", &responseCode) != 1) return False;
  // Note: We check for HTTP responses as well as RTSP responses, both in order to setup RTSP-over-HTTP tunneling,
  // and so that we get back a meaningful error if the client tried to mistakenly send a RTSP command to a HTTP-only server.

  // Use everything after the RTSP/* (or HTTP/*) as the response string:
  responseString = line;
  while (responseString[0] != '\0' && responseString[0] != ' '  && responseString[0] != '\t') ++responseString;
  while (responseString[0] != '\0' && (responseString[0] == ' '  || responseString[0] == '\t')) ++responseString; // skip whitespace

  return True;
}

void RTSPClient::handleIncomingRequest() {
  // Parse the request string into command name and 'CSeq', then 'handle' the command (by responding that we don't support it):
  char cmdName[RTSP_PARAM_STRING_MAX];
  char urlPreSuffix[RTSP_PARAM_STRING_MAX];
  char urlSuffix[RTSP_PARAM_STRING_MAX];
  char cseq[RTSP_PARAM_STRING_MAX];
  char sessionId[RTSP_PARAM_STRING_MAX];
  unsigned contentLength;
  if (!parseRTSPRequestString(fResponseBuffer, fResponseBytesAlreadySeen,
			      cmdName, sizeof cmdName,
			      urlPreSuffix, sizeof urlPreSuffix,
			      urlSuffix, sizeof urlSuffix,
			      cseq, sizeof cseq,
			      sessionId, sizeof sessionId,
			      contentLength)) {
    return;
  } else {
    if (fVerbosityLevel >= 1) {
      envir() << "Received incoming RTSP request: " << fResponseBuffer << "\n";
    }
    char tmpBuf[2*RTSP_PARAM_STRING_MAX];
    snprintf(tmpBuf, sizeof tmpBuf,
             "RTSP/1.0 405 Method Not Allowed\r\nCSeq: %s\r\n\r\n", cseq);
    write(tmpBuf, strlen(tmpBuf));
  }
}

Boolean RTSPClient::checkForHeader(char const* line, char const* headerName, unsigned headerNameLength, char const*& headerParams) {
  if (_strncasecmp(line, headerName, headerNameLength) != 0) return False;

  // The line begins with the desired header name.  Trim off any whitespace, and return the header parameters:
  unsigned paramIndex = headerNameLength;
  while (line[paramIndex] != '\0' && (line[paramIndex] == ' ' || line[paramIndex] == '\t')) ++paramIndex;
  if (line[paramIndex] == '\0') return False; // the header is assumed to be bad if it has no parameters

  headerParams = &line[paramIndex];
  return True;
}

Boolean RTSPClient::parseTransportParams(char const* paramsStr,
					 char*& serverAddressStr, portNumBits& serverPortNum,
					 unsigned char& rtpChannelId, unsigned char& rtcpChannelId) {
  // Initialize the return parameters to 'not found' values:
  serverAddressStr = NULL;
  serverPortNum = 0;
  rtpChannelId = rtcpChannelId = 0xFF;
  if (paramsStr == NULL) return False;  

  char* foundServerAddressStr = NULL;
  Boolean foundServerPortNum = False;
  portNumBits clientPortNum = 0;
  Boolean foundClientPortNum = False;
  Boolean foundChannelIds = False;
  unsigned rtpCid, rtcpCid;
  Boolean isMulticast = True; // by default
  char* foundDestinationStr = NULL;
  portNumBits multicastPortNumRTP, multicastPortNumRTCP;
  Boolean foundMulticastPortNum = False;

  // Run through each of the parameters, looking for ones that we handle:
  char const* fields = paramsStr;
  char* field = strDupSize(fields);
  while (sscanf(fields, "%[^;]", field) == 1) {
    if (sscanf(field, "server_port=%hu", &serverPortNum) == 1) {
      foundServerPortNum = True;
    } else if (sscanf(field, "client_port=%hu", &clientPortNum) == 1) {
      foundClientPortNum = True;
    } else if (_strncasecmp(field, "source=", 7) == 0) {
      delete[] foundServerAddressStr;
      foundServerAddressStr = strDup(field+7);
    } else if (sscanf(field, "interleaved=%u-%u", &rtpCid, &rtcpCid) == 2) {
      rtpChannelId = (unsigned char)rtpCid;
      rtcpChannelId = (unsigned char)rtcpCid;
      foundChannelIds = True;
    } else if (strcmp(field, "unicast") == 0) {
      isMulticast = False;
    } else if (_strncasecmp(field, "destination=", 12) == 0) {
      delete[] foundDestinationStr;
      foundDestinationStr = strDup(field+12);
    } else if (sscanf(field, "port=%hu-%hu", &multicastPortNumRTP, &multicastPortNumRTCP) == 2 ||
	       sscanf(field, "port=%hu", &multicastPortNumRTP) == 1) {
      foundMulticastPortNum = True;
    }

    fields += strlen(field);
    while (fields[0] == ';') ++fields; // skip over all leading ';' chars
    if (fields[0] == '\0') break;
  }
  delete[] field;

  // If we're multicast, and have a "destination=" (multicast) address, then use this
  // as the 'server' address (because some weird servers don't specify the multicast
  // address earlier, in the "DESCRIBE" response's SDP:
  if (isMulticast && foundDestinationStr != NULL && foundMulticastPortNum) {
    delete[] foundServerAddressStr;
    serverAddressStr = foundDestinationStr;
    serverPortNum = multicastPortNumRTP;
    return True;
  }
  delete[] foundDestinationStr;

  // We have a valid "Transport:" header if any of the following are true:
  //   - We saw a "interleaved=" field, indicating RTP/RTCP-over-TCP streaming, or
  //   - We saw a "server_port=" field, or
  //   - We saw a "client_port=" field.
  //     If we didn't also see a "server_port=" field, then the server port is assumed to be the same as the client port.
  if (foundChannelIds || foundServerPortNum || foundClientPortNum) {
    if (foundClientPortNum && !foundServerPortNum) {
      serverPortNum = clientPortNum;
    }
    serverAddressStr = foundServerAddressStr;
    return True;
  }

  delete[] foundServerAddressStr;
  return False;
}

Boolean RTSPClient::parseScaleParam(char const* paramStr, float& scale) {
  Locale l("C", Numeric);
  return sscanf(paramStr, "%f", &scale) == 1;
}

Boolean RTSPClient::parseSpeedParam(char const* paramStr, float& speed) {
  Locale l("C", Numeric);
  return sscanf(paramStr, "%f", &speed) >= 1;
}

Boolean RTSPClient::parseRTPInfoParams(char const*& paramsStr, u_int16_t& seqNum, u_int32_t& timestamp) {
  if (paramsStr == NULL || paramsStr[0] == '\0') return False;
  while (paramsStr[0] == ',') ++paramsStr;

  // "paramsStr" now consists of a ';'-separated list of parameters, ending with ',' or '\0'.
  char* field = strDupSize(paramsStr);

  Boolean sawSeq = False, sawRtptime = False;
  while (sscanf(paramsStr, "%[^;,]", field) == 1) {
    if (sscanf(field, "seq=%hu", &seqNum) == 1) {
      sawSeq = True;
    } else if (sscanf(field, "rtptime=%u", &timestamp) == 1) {
      sawRtptime = True;
    }

    paramsStr += strlen(field);
    if (paramsStr[0] == '\0' || paramsStr[0] == ',') break;
    // ASSERT: paramsStr[0] == ';'
    ++paramsStr; // skip over the ';'
  }

  delete[] field;
  // For the "RTP-Info:" parameters to be useful to us, we need to have seen both the "seq=" and "rtptime=" parameters:
  return sawSeq && sawRtptime;
}

Boolean RTSPClient::handleSETUPResponse(MediaSubsession& subsession, char const* sessionParamsStr, char const* transportParamsStr,
                                        Boolean streamUsingTCP) {
  char* sessionId = new char[responseBufferSize]; // ensures we have enough space
  Boolean success = False;
  do {
    // Check for a session id:
    if (sessionParamsStr == NULL || sscanf(sessionParamsStr, "%[^;]", sessionId) != 1) {
      envir().setResultMsg("Missing or bad \"Session:\" header");
      break;
    }
    subsession.setSessionId(sessionId);
    delete[] fLastSessionId; fLastSessionId = strDup(sessionId);

    // Also look for an optional "; timeout = " parameter following this:
    char const* afterSessionId = sessionParamsStr + strlen(sessionId);
    int timeoutVal;
    if (sscanf(afterSessionId, "; timeout = %d", &timeoutVal) == 1) {
      fSessionTimeoutParameter = timeoutVal;
    }

    // Parse the "Transport:" header parameters:
    char* serverAddressStr;
    portNumBits serverPortNum;
    unsigned char rtpChannelId, rtcpChannelId;
    if (!parseTransportParams(transportParamsStr, serverAddressStr, serverPortNum, rtpChannelId, rtcpChannelId)) {
      envir().setResultMsg("Missing or bad \"Transport:\" header");
      break;
    }
    delete[] subsession.connectionEndpointName();
    subsession.connectionEndpointName() = serverAddressStr;
    subsession.serverPortNum = serverPortNum;
    subsession.rtpChannelId = rtpChannelId;
    subsession.rtcpChannelId = rtcpChannelId;

    if (streamUsingTCP) {
      // Tell the subsession to receive RTP (and send/receive RTCP) over the RTSP stream:
      if (subsession.rtpSource() != NULL) {
	subsession.rtpSource()->setStreamSocket(fInputSocketNum, subsession.rtpChannelId);
	  // So that we continue to receive & handle RTSP commands and responses from the server
	subsession.rtpSource()->enableRTCPReports() = False;
	  // To avoid confusing the server (which won't start handling RTP/RTCP-over-TCP until "PLAY"), don't send RTCP "RR"s yet
	increaseReceiveBufferTo(envir(), fInputSocketNum, 50*1024);
      }
      if (subsession.rtcpInstance() != NULL) subsession.rtcpInstance()->setStreamSocket(fInputSocketNum, subsession.rtcpChannelId);
      RTPInterface::setServerRequestAlternativeByteHandler(envir(), fInputSocketNum, handleAlternativeRequestByte, this);
    } else {
      // Normal case.
      // Set the RTP and RTCP sockets' destination address and port from the information in the SETUP response (if present):
      netAddressBits destAddress = subsession.connectionEndpointAddress();
      if (destAddress == 0) destAddress = fServerAddress;
      subsession.setDestinations(destAddress);
    }

    success = True;
  } while (0);

  delete[] sessionId;
  return success;
}

Boolean RTSPClient::handlePLAYResponse(MediaSession* session, MediaSubsession* subsession,
                                       char const* scaleParamsStr, char const* speedParamsStr,
                                       char const* rangeParamsStr, char const* rtpInfoParamsStr) {
  Boolean scaleOK = False, rangeOK = False, speedOK = False;
  do {
    if (session != NULL) {
      // The command was on the whole session
      if (scaleParamsStr != NULL && !parseScaleParam(scaleParamsStr, session->scale())) break;
      scaleOK = True;
      if (speedParamsStr != NULL && !parseSpeedParam(speedParamsStr, session->speed())) break;
      speedOK = True;
      Boolean startTimeIsNow;
      if (rangeParamsStr != NULL &&
	  !parseRangeParam(rangeParamsStr,
               session->playStartTime(), session->playEndTime(),
               session->_absStartTime(), session->_absEndTime(),
			   startTimeIsNow)) break;
      rangeOK = True;

      MediaSubsessionIterator iter(*session);
      MediaSubsession* subsession;
      while ((subsession = iter.next()) != NULL) {
	u_int16_t seqNum; u_int32_t timestamp;
	subsession->rtpInfo.infoIsNew = False;
	if (parseRTPInfoParams(rtpInfoParamsStr, seqNum, timestamp)) {
	  subsession->rtpInfo.seqNum = seqNum;
	  subsession->rtpInfo.timestamp = timestamp;
	  subsession->rtpInfo.infoIsNew = True;
	}

	if (subsession->rtpSource() != NULL) subsession->rtpSource()->enableRTCPReports() = True; // start sending RTCP "RR"s now
      }
    } else {
      // The command was on a subsession
      if (scaleParamsStr != NULL && !parseScaleParam(scaleParamsStr, subsession->scale())) break;
      scaleOK = True;
      if (speedParamsStr != NULL && !parseSpeedParam(speedParamsStr, subsession->speed())) break;
      speedOK = True;
      Boolean startTimeIsNow;
      if (rangeParamsStr != NULL &&
	  !parseRangeParam(rangeParamsStr,
               subsession->_playStartTime(), subsession->_playEndTime(),
               subsession->_absStartTime(), subsession->_absEndTime(),
			   startTimeIsNow)) break;
      rangeOK = True;

      u_int16_t seqNum; u_int32_t timestamp;
      subsession->rtpInfo.infoIsNew = False;
      if (parseRTPInfoParams(rtpInfoParamsStr, seqNum, timestamp)) {
    subsession->rtpInfo.seqNum = seqNum;
    subsession->rtpInfo.timestamp = timestamp;
    subsession->rtpInfo.infoIsNew = True;
      }

      if (subsession->rtpSource() != NULL) subsession->rtpSource()->enableRTCPReports() = True; // start sending RTCP "RR"s now
    }

    return True;
  } while (0);

  // An error occurred:
  if (!scaleOK) {
    envir().setResultMsg("Bad \"Scale:\" header");
  } else if (!speedOK) {
    envir().setResultMsg("Bad \"Speed:\" header");
  } else if (!rangeOK) {
    envir().setResultMsg("Bad \"Range:\" header");
  } else {
    envir().setResultMsg("Bad \"RTP-Info:\" header");
  }
  return False;
}

Boolean RTSPClient::handleTEARDOWNResponse(MediaSession& /*session*/, MediaSubsession& /*subsession*/) {
  // Because we don't expect to always get a response to "TEARDOWN", we don't need to do anything if we do get one:
  return True;
}

Boolean RTSPClient::handleGET_PARAMETERResponse(char const* parameterName, char*& resultValueString, char* resultValueStringEnd) {
  do {
    // If "parameterName" is non-empty, it may be (possibly followed by ':' and whitespace) at the start of the result string:
    if (parameterName != NULL && parameterName[0] != '\0') {
      if (parameterName[1] == '\0') break; // sanity check; there should have been \r\n at the end of "parameterName"

      unsigned parameterNameLen = strlen(parameterName);
      // ASSERT: parameterNameLen >= 2;
      parameterNameLen -= 2; // because of the trailing \r\n
      if (resultValueString + parameterNameLen > resultValueStringEnd) break; // not enough space
      if (parameterNameLen > 0 && _strncasecmp(resultValueString, parameterName, parameterNameLen) == 0) {
	resultValueString += parameterNameLen;
	// ASSERT: resultValueString <= resultValueStringEnd
	if (resultValueString == resultValueStringEnd) break;

	if (resultValueString[0] == ':') ++resultValueString;
	while (resultValueString < resultValueStringEnd
	       && (resultValueString[0] == ' ' || resultValueString[0] == '\t')) {
	  ++resultValueString;
	}
      }
    }

    // The rest of "resultValueStr" should be our desired result, but first trim off any \r and/or \n characters at the end:
    char saved = *resultValueStringEnd;
    *resultValueStringEnd = '\0';
    unsigned resultLen = strlen(resultValueString);
    *resultValueStringEnd = saved;
    
    while (resultLen > 0 && (resultValueString[resultLen-1] == '\r' || resultValueString[resultLen-1] == '\n')) --resultLen;
    resultValueString[resultLen] = '\0';

    return True;
  } while (0);

  // An error occurred:
  envir().setResultMsg("Bad \"GET_PARAMETER\" response");
  return False;
}

Boolean RTSPClient::handleAuthenticationFailure(char const* paramsStr) {
  if (paramsStr == NULL) return False; // There was no "WWW-Authenticate:" header; we can't proceed.

  // Fill in "fCurrentAuthenticator" with the information from the "WWW-Authenticate:" header:
  Boolean realmHasChanged = False; // by default
  Boolean isStale = False; // by default
  char* realm = strDupSize(paramsStr);
  char* nonce = strDupSize(paramsStr);
  char* stale = strDupSize(paramsStr);
  Boolean success = True;
  if (sscanf(paramsStr, "Digest realm=\"%[^\"]\", nonce=\"%[^\"]\", stale=%[a-zA-Z]", realm, nonce, stale) == 3) {
    realmHasChanged = fCurrentAuthenticator.realm() == NULL || strcmp(fCurrentAuthenticator.realm(), realm) != 0;
    isStale = _strncasecmp(stale, "true", 4) == 0;
    fCurrentAuthenticator.setRealmAndNonce(realm, nonce);
  } else if (sscanf(paramsStr, "Digest realm=\"%[^\"]\", nonce=\"%[^\"]\"", realm, nonce) == 2) {
    realmHasChanged = fCurrentAuthenticator.realm() == NULL || strcmp(fCurrentAuthenticator.realm(), realm) != 0;
    fCurrentAuthenticator.setRealmAndNonce(realm, nonce);
  } else if (sscanf(paramsStr, "Basic realm=\"%[^\"]\"", realm) == 1 && fAllowBasicAuthentication) {
    realmHasChanged = fCurrentAuthenticator.realm() == NULL || strcmp(fCurrentAuthenticator.realm(), realm) != 0;
    fCurrentAuthenticator.setRealmAndNonce(realm, NULL); // Basic authentication
  } else {
    success = False; // bad "WWW-Authenticate:" header
  }
  delete[] realm; delete[] nonce; delete[] stale;

  if (success) {
    if ((!realmHasChanged && !isStale) || fCurrentAuthenticator.username() == NULL || fCurrentAuthenticator.password() == NULL) {
      // We already tried with the same realm (and a non-stale nonce),
      // or don't have a username and/or password, so the new "WWW-Authenticate:" header
      // information won't help us.  We remain unauthenticated.
      success = False;
    }
  }

  return success;
}

Boolean RTSPClient::resendCommand(RequestRecord* request) {
  if (fVerbosityLevel >= 1) envir() << "Resending...\n";
  if (request != NULL && strcmp(request->commandName(), "GET") != 0) request->cseq() = ++fCSeq;
  return sendRequest(request) != 0;
}

char const* RTSPClient::sessionURL(MediaSession const& session) const {
  char const* url = session.controlPath();
  if (url == NULL || strcmp(url, "*") == 0) url = fBaseURL;

  return url;
}

void RTSPClient::handleAlternativeRequestByte(void* rtspClient, u_int8_t requestByte) {
  ((RTSPClient*)rtspClient)->handleAlternativeRequestByte1(requestByte);
}

void RTSPClient::handleAlternativeRequestByte1(u_int8_t requestByte) {
  if (requestByte == 0xFF) {
    // Hack: The new handler of the input TCP socket encountered an error reading it.  Indicate this:
    handleResponseBytes(-1);
  } else if (requestByte == 0xFE) {
    // Another hack: The new handler of the input TCP socket no longer needs it, so take back control:
    envir().taskScheduler().setBackgroundHandling(fInputSocketNum, SOCKET_READABLE|SOCKET_EXCEPTION,
						  (TaskScheduler::BackgroundHandlerProc*)&incomingDataHandler, this);
  } else {
    // Normal case:
    fResponseBuffer[fResponseBytesAlreadySeen] = requestByte;
    handleResponseBytes(1);
  }
}

static Boolean isAbsoluteURL(char const* url) {
  // Assumption: "url" is absolute if it contains a ':', before any
  // occurrence of '/'
  while (*url != '\0' && *url != '/') {
    if (*url == ':') return True;
    ++url;
  }

  return False;
}

void RTSPClient::constructSubsessionURL(MediaSubsession const& subsession,
					char const*& prefix,
					char const*& separator,
					char const*& suffix) {
  // Figure out what the URL describing "subsession" will look like.
  // The URL is returned in three parts: prefix; separator; suffix
  //##### NOTE: This code doesn't really do the right thing if "sessionURL()"
  // doesn't end with a "/", and "subsession.controlPath()" is relative.
  // The right thing would have been to truncate "sessionURL()" back to the
  // rightmost "/", and then add "subsession.controlPath()".
  // In practice, though, each "DESCRIBE" response typically contains
  // a "Content-Base:" header that consists of "sessionURL()" followed by
  // a "/", in which case this code ends up giving the correct result.
  // However, we should really fix this code to do the right thing, and
  // also check for and use the "Content-Base:" header appropriately. #####
  prefix = sessionURL(subsession.parentSession());
  if (prefix == NULL) prefix = "";

  suffix = subsession.controlPath();
  if (suffix == NULL) suffix = "";

  if (isAbsoluteURL(suffix)) {
    prefix = separator = "";
  } else {
    unsigned prefixLen = strlen(prefix);
    separator = (prefixLen == 0 || prefix[prefixLen-1] == '/' || suffix[0] == '/') ? "" : "/";
  }
}

Boolean RTSPClient::setupHTTPTunneling1() {
  // Set up RTSP-over-HTTP tunneling, as described in
  //     http://mirror.informatimago.com/next/developer.apple.com/quicktime/icefloe/dispatch028.html
  // and http://images.apple.com/br/quicktime/pdf/QTSS_Modules.pdf
  if (fVerbosityLevel >= 1) {
    envir() << "Requesting RTSP-over-HTTP tunneling (on port " << fTunnelOverHTTPPortNum << ")\n\n";
  }

  // Begin by sending a HTTP "GET", to set up the server->client link.  Continue when we handle the response:
  return sendRequest(new RequestRecord(1, "GET", responseHandlerForHTTP_GET)) != 0;
}

void RTSPClient::responseHandlerForHTTP_GET(RTSPClient* rtspClient, int responseCode, char* responseString) {
  if (rtspClient != NULL) rtspClient->responseHandlerForHTTP_GET1(responseCode, responseString);
}

void RTSPClient::responseHandlerForHTTP_GET1(int responseCode, char* responseString) {
  RequestRecord* request;
  do {
    delete[] responseString; // we don't need it (but are responsible for deleting it)
    if (responseCode != 0) break; // The HTTP "GET" failed.

    // Having successfully set up (using the HTTP "GET" command) the server->client link, set up a second TCP connection
    // (to the same server & port as before) for the client->server link.  All future output will be to this new socket.
    fOutputSocketNum = setupStreamSocket(envir(), 0);
    if (fOutputSocketNum < 0) break;
    ignoreSigPipeOnSocket(fOutputSocketNum); // so that servers on the same host that killed don't also kill us

    fHTTPTunnelingConnectionIsPending = True;
    int connectResult = connectToServer(fOutputSocketNum, fTunnelOverHTTPPortNum);
    if (connectResult < 0) break; // an error occurred
    else if (connectResult == 0) {
      // A connection is pending.  Continue setting up RTSP-over-HTTP when the connection completes.
      // First, move the pending requests to the 'awaiting connection' queue:
      while ((request = fRequestsAwaitingHTTPTunneling.dequeue()) != NULL) {
	fRequestsAwaitingConnection.enqueue(request);
      }
      return;
    }

    // The connection succeeded.  Continue setting up RTSP-over-HTTP:
    if (!setupHTTPTunneling2()) break;

    // RTSP-over-HTTP tunneling succeeded.  Resume the pending request(s):
    while ((request = fRequestsAwaitingHTTPTunneling.dequeue()) != NULL) {
      sendRequest(request);
    }
    return;
  } while (0);

  // An error occurred.  Dequeue the pending request(s), and tell them about the error:
  fHTTPTunnelingConnectionIsPending = False;
  resetTCPSockets(); // do this now, in case an error handler deletes "this"
  RequestQueue requestQueue(fRequestsAwaitingHTTPTunneling);
  while ((request = requestQueue.dequeue()) != NULL) {
    handleRequestError(request);
    delete request;
  }
}

Boolean RTSPClient::setupHTTPTunneling2() {
  fHTTPTunnelingConnectionIsPending = False;

  // Send a HTTP "POST", to set up the client->server link.  (Note that we won't see a reply to the "POST".)
  return sendRequest(new RequestRecord(1, "POST", NULL)) != 0;
}

void RTSPClient::connectionHandler(void* instance, int /*mask*/) {
  RTSPClient* client = (RTSPClient*)instance;
  client->connectionHandler1();
}

void RTSPClient::connectionHandler1() {
  // Restore normal handling on our sockets:
  envir().taskScheduler().disableBackgroundHandling(fOutputSocketNum);
  envir().taskScheduler().setBackgroundHandling(fInputSocketNum, SOCKET_READABLE|SOCKET_EXCEPTION,
						(TaskScheduler::BackgroundHandlerProc*)&incomingDataHandler, this);

  // Move all requests awaiting connection into a new, temporary queue, to clear "fRequestsAwaitingConnection"
  // (so that "sendRequest()" doesn't get confused by "fRequestsAwaitingConnection" being nonempty, and enqueue them all over again).
  RequestQueue tmpRequestQueue(fRequestsAwaitingConnection);
  RequestRecord* request;

  // Find out whether the connection succeeded or failed:
  do {
    int err = 0;
    SOCKLEN_T len = sizeof err;
    if (getsockopt(fInputSocketNum, SOL_SOCKET, SO_ERROR, (char*)&err, &len) < 0 || err != 0) {
      envir().setResultErrMsg("Connection to server failed: ", err);
      if (fVerbosityLevel >= 1) envir() << "..." << envir().getResultMsg() << "\n";
      break;
    }

    // The connection succeeded.  If the connection came about from an attempt to set up RTSP-over-HTTP, finish this now:
    if (fHTTPTunnelingConnectionIsPending && !setupHTTPTunneling2()) break;

    if (fTLS.isNeeded) {
      // We need to complete an additional TLS connection:
      int tlsConnectResult = fTLS.connect(fInputSocketNum);
      if (tlsConnectResult < 0) break; // error in TLS connection
      if (tlsConnectResult > 0 && fVerbosityLevel >= 1) envir() << "...TLS connection completed\n";
      if (tlsConnectResult == 0) {
	// The connection is still pending.  Continue deferring...
	while ((request = tmpRequestQueue.dequeue()) != NULL) {
	  fRequestsAwaitingConnection.enqueue(request);
	}
	return;
      }
    }

    // The connection is complete.  Resume sending all pending requests:
    if (fVerbosityLevel >= 1) envir() << "...remote connection opened\n";
    while ((request = tmpRequestQueue.dequeue()) != NULL) {
      sendRequest(request);
    }
    return;
  } while (0);

  // An error occurred.  Tell all pending requests about the error:
  resetTCPSockets(); // do this now, in case an error handler deletes "this"
  while ((request = tmpRequestQueue.dequeue()) != NULL) {
    handleRequestError(request);
    delete request;
  }
}

void RTSPClient::incomingDataHandler(void* instance, int /*mask*/) {
  RTSPClient* client = (RTSPClient*)instance;
  client->incomingDataHandler1();
}

void RTSPClient::incomingDataHandler1() {
  int bytesRead = read((u_int8_t*)&fResponseBuffer[fResponseBytesAlreadySeen], fResponseBufferBytesLeft);
  handleResponseBytes(bytesRead);
}

static char* getLine(char* startOfLine) {
  // returns the start of the next line, or NULL if none.  Note that this modifies the input string to add '\0' characters.
  for (char* ptr = startOfLine; *ptr != '\0'; ++ptr) {
    // Check for the end of line: \r\n (but also accept \r or \n by itself):
    if (*ptr == '\r' || *ptr == '\n') {
      // We found the end of the line
      if (*ptr == '\r') {
	*ptr++ = '\0';
	if (*ptr == '\n') ++ptr;
      } else {
        *ptr++ = '\0';
      }
      return ptr;
    }
  }

  return NULL;
}

void RTSPClient::handleResponseBytes(int newBytesRead) {
  do {
    if (newBytesRead >= 0 && (unsigned)newBytesRead < fResponseBufferBytesLeft) break; // data was read OK; process it below

    if (newBytesRead >= (int)fResponseBufferBytesLeft) {
      // We filled up our response buffer.  Treat this as an error (for the first response handler):
      envir().setResultMsg("RTSP response was truncated. Increase \"RTSPClient::responseBufferSize\"");
    }

    // An error occurred while reading our TCP socket.  Call all pending response handlers, indicating this error.
    // (However, the "RTSP response was truncated" error is applied to the first response handler only.)
    resetResponseBuffer();
    RequestRecord* request;
    if (newBytesRead > 0) { // The "RTSP response was truncated" error
      if ((request = fRequestsAwaitingResponse.dequeue()) != NULL) {
	handleRequestError(request);
	delete request;
      }
    } else {
      RequestQueue requestQueue(fRequestsAwaitingResponse);
      resetTCPSockets(); // do this now, in case an error handler deletes "this"

      while ((request = requestQueue.dequeue()) != NULL) {
	handleRequestError(request);
	delete request;
      }
    }
    return;
  } while (0);

  fResponseBufferBytesLeft -= newBytesRead;
  fResponseBytesAlreadySeen += newBytesRead;
  fResponseBuffer[fResponseBytesAlreadySeen] = '\0';
  if (fVerbosityLevel >= 1 && newBytesRead > 1) envir() << "Received " << newBytesRead << " new bytes of response data.\n";
  
  unsigned numExtraBytesAfterResponse = 0;
  Boolean responseSuccess = False; // by default
  do {
    // Data was read OK.  Look through the data that we've read so far, to see if it contains <CR><LF><CR><LF>.
    // (If not, wait for more data to arrive.)
    Boolean endOfHeaders = False;
    char const* ptr = fResponseBuffer;
    if (fResponseBytesAlreadySeen > 3) {
      char const* const ptrEnd = &fResponseBuffer[fResponseBytesAlreadySeen-3];
      while (ptr < ptrEnd) {
	if (*ptr++ == '\r' && *ptr++ == '\n' && *ptr++ == '\r' && *ptr++ == '\n') {
	  // This is it
	  endOfHeaders = True;
	  break;
	}
      }
    }
    
    if (!endOfHeaders) return; // subsequent reads will be needed to get the complete response
    
    // Now that we have the complete response headers (ending with <CR><LF><CR><LF>), parse them to get the response code, CSeq,
    // and various other header parameters.  To do this, we first make a copy of the received header data, because we'll be
    // modifying it by adding '\0' bytes.
    char* headerDataCopy;
    unsigned responseCode = 200;
    char const* responseStr = NULL;
    RequestRecord* foundRequest = NULL;
    char const* sessionParamsStr = NULL;
    char const* transportParamsStr = NULL;
    char const* scaleParamsStr = NULL;
    char const* speedParamsStr = NULL;
    char const* rangeParamsStr = NULL;
    char const* rtpInfoParamsStr = NULL;
    char const* wwwAuthenticateParamsStr = NULL;
    char const* publicParamsStr = NULL;
    char* bodyStart = NULL;
    unsigned numBodyBytes = 0;
    responseSuccess = False;
    do {
      headerDataCopy = new char[responseBufferSize];
      strncpy(headerDataCopy, fResponseBuffer, fResponseBytesAlreadySeen);
      headerDataCopy[fResponseBytesAlreadySeen] = '\0';
      
      char* lineStart;
      char* nextLineStart = headerDataCopy;
      do {
	lineStart = nextLineStart;
	nextLineStart = getLine(lineStart);
      } while (lineStart[0] == '\0' && nextLineStart != NULL); // skip over any blank lines at the start
      if (!parseResponseCode(lineStart, responseCode, responseStr)) {
	// This does not appear to be a RTSP response; perhaps it's a RTSP request instead?
	handleIncomingRequest();
	break; // we're done with this data
      }
      
      // Scan through the headers, handling the ones that we're interested in:
      Boolean reachedEndOfHeaders;
      unsigned cseq = 0;
      unsigned contentLength = 0;
      
      while (1) {
	reachedEndOfHeaders = True; // by default; may get changed below
	lineStart = nextLineStart;
	if (lineStart == NULL) break;
	
	nextLineStart = getLine(lineStart);
	if (lineStart[0] == '\0') break; // this is a blank line
	reachedEndOfHeaders = False;
	
	char const* headerParamsStr; 
	if (checkForHeader(lineStart, "CSeq:", 5, headerParamsStr)) {
	  if (sscanf(headerParamsStr, "%u", &cseq) != 1 || cseq <= 0) {
	    envir().setResultMsg("Bad \"CSeq:\" header: \"", lineStart, "\"");
	    break;
	  }
	  // Find the handler function for "cseq":
	  RequestRecord* request;
	  while ((request = fRequestsAwaitingResponse.dequeue()) != NULL) {
	    if (request->cseq() < cseq) { // assumes that the CSeq counter will never wrap around
	      // We never received (and will never receive) a response for this handler, so delete it:
	      if (fVerbosityLevel >= 1 && strcmp(request->commandName(), "POST") != 0) {
		envir() << "WARNING: The server did not respond to our \"" << request->commandName() << "\" request (CSeq: "
			<< request->cseq() << ").  The server appears to be buggy (perhaps not handling pipelined requests properly).\n";
	      }
	      delete request;
	    } else if (request->cseq() == cseq) {
	      // This is the handler that we want. Remove its record, but remember it, so that we can later call its handler:
	      foundRequest = request;
	      break;
	    } else { // request->cseq() > cseq
	      // No handler was registered for this response, so ignore it.
	      break;
	    }
	  }
	} else if (checkForHeader(lineStart, "Content-Length:", 15, headerParamsStr)) {
	  if (sscanf(headerParamsStr, "%u", &contentLength) != 1) {
	    envir().setResultMsg("Bad \"Content-Length:\" header: \"", lineStart, "\"");
	    break;
	  }
	} else if (checkForHeader(lineStart, "Content-Base:", 13, headerParamsStr)) {
	  setBaseURL(headerParamsStr);
	} else if (checkForHeader(lineStart, "Session:", 8, sessionParamsStr)) {
	} else if (checkForHeader(lineStart, "Transport:", 10, transportParamsStr)) {
	} else if (checkForHeader(lineStart, "Scale:", 6, scaleParamsStr)) {
	} else if (checkForHeader(lineStart, "Speed:",
// NOTE: Should you feel the need to modify this code,
				  6,
// please first email the "live-devel" mailing list
				  speedParamsStr
// (see http://live555.com/liveMedia/faq.html#mailing-list-address for details),
				  )) {
// to check whether your proposed modification is appropriate/correct,
	} else if (checkForHeader(lineStart, "Range:",
// and, if so, whether instead it could be included in
				  6,
// a future release of the "LIVE555 Streaming Media" software,
				  rangeParamsStr
// so that other projects that use the code could benefit (not just your own project).
				  )) {
	} else if (checkForHeader(lineStart, "RTP-Info:", 9, rtpInfoParamsStr)) {
	} else if (checkForHeader(lineStart, "WWW-Authenticate:", 17, headerParamsStr)) {
	  // If we've already seen a "WWW-Authenticate:" header, then we replace it with this new one only if
	  // the new one specifies "Digest" authentication:
	  if (wwwAuthenticateParamsStr == NULL || _strncasecmp(headerParamsStr, "Digest", 6) == 0) {
	    wwwAuthenticateParamsStr = headerParamsStr;
	  }
	} else if (checkForHeader(lineStart, "Public:", 7, publicParamsStr)) {
	} else if (checkForHeader(lineStart, "Allow:", 6, publicParamsStr)) {
	  // Note: we accept "Allow:" instead of "Public:", so that "OPTIONS" requests made to HTTP servers will work.
	} else if (checkForHeader(lineStart, "Location:", 9, headerParamsStr)) {
	  setBaseURL(headerParamsStr);
	} else if (checkForHeader(lineStart, "com.ses.streamID:", 17, headerParamsStr)) {
	  // Replace the tail of the 'base URL' with the value of this header parameter:
	  char* oldBaseURLTail = strrchr(fBaseURL, '/');
	  if (oldBaseURLTail != NULL) {
	    unsigned newBaseURLLen
	      = (oldBaseURLTail - fBaseURL) + 8/* for "/stream=" */ + strlen(headerParamsStr);
	    char* newBaseURL = new char[newBaseURLLen + 1];
	        // Note: We couldn't use "asprintf()", because some compilers don't support it
	    sprintf(newBaseURL, "%.*s/stream=%s",
		     (int)(oldBaseURLTail - fBaseURL), fBaseURL, headerParamsStr);
	    setBaseURL(newBaseURL);
	    delete[] newBaseURL;
	  }
	} else if (checkForHeader(lineStart, "Connection:", 11, headerParamsStr)) {
	  if (fTunnelOverHTTPPortNum == 0 && _strncasecmp(headerParamsStr, "Close", 5) == 0) {
	    resetTCPSockets();
	  }
	}
      }
      if (!reachedEndOfHeaders) break; // an error occurred
      
      if (foundRequest == NULL) {
	// Hack: The response didn't have a "CSeq:" header; assume it's for our most recent request:
	foundRequest = fRequestsAwaitingResponse.dequeue();
      }
      
      // If we saw a "Content-Length:" header, then make sure that we have the amount of data that it specified:
      unsigned bodyOffset = nextLineStart == NULL ? fResponseBytesAlreadySeen : nextLineStart - headerDataCopy;
      bodyStart = &fResponseBuffer[bodyOffset];
      numBodyBytes = fResponseBytesAlreadySeen - bodyOffset;
      if (contentLength > numBodyBytes) {
	// We need to read more data.  First, make sure we have enough space for it:
	unsigned numExtraBytesNeeded = contentLength - numBodyBytes;
	unsigned remainingBufferSize = responseBufferSize - fResponseBytesAlreadySeen;
	if (numExtraBytesNeeded > remainingBufferSize) {
	  char tmpBuf[200];
	  sprintf(tmpBuf, "Response buffer size (%d) is too small for \"Content-Length:\" %d (need a buffer size of >= %d bytes\n",
		  responseBufferSize, contentLength, fResponseBytesAlreadySeen + numExtraBytesNeeded);
	  envir().setResultMsg(tmpBuf);
	  break;
	}
	
	if (fVerbosityLevel >= 1) {
	  envir() << "Have received " << fResponseBytesAlreadySeen << " total bytes of a "
		  << (foundRequest != NULL ? foundRequest->commandName() : "(unknown)")
		  << " RTSP response; awaiting " << numExtraBytesNeeded << " bytes more.\n";
	}
	delete[] headerDataCopy;
	if (foundRequest != NULL) fRequestsAwaitingResponse.putAtHead(foundRequest);// put our request record back; we need it again
	return; // We need to read more data
      }
      
      // We now have a complete response (including all bytes specified by the "Content-Length:" header, if any).
      char* responseEnd = bodyStart + contentLength;
      numExtraBytesAfterResponse = &fResponseBuffer[fResponseBytesAlreadySeen] - responseEnd;

      if (fVerbosityLevel >= 1) {
	char saved = *responseEnd;
	*responseEnd = '\0';
	envir() << "Received a complete "
		<< (foundRequest != NULL ? foundRequest->commandName() : "(unknown)")
		<< " response:\n" << fResponseBuffer << "\n";
	if (numExtraBytesAfterResponse > 0) envir() << "\t(plus " << numExtraBytesAfterResponse << " additional bytes)\n";
	*responseEnd = saved;
      }
      
      if (foundRequest != NULL) {
	Boolean needToResendCommand = False; // by default...
	if (responseCode == 200) {
	  // Do special-case response handling for some commands:
	  if (strcmp(foundRequest->commandName(), "SETUP") == 0) {
        if (!handleSETUPResponse(*foundRequest->subsession(), sessionParamsStr, transportParamsStr, foundRequest->booleanFlags()&0x1)) break;
	  } else if (strcmp(foundRequest->commandName(), "PLAY") == 0) {
        if (!handlePLAYResponse(foundRequest->session(), foundRequest->subsession(), scaleParamsStr, speedParamsStr, rangeParamsStr, rtpInfoParamsStr)) break;
	  } else if (strcmp(foundRequest->commandName(), "TEARDOWN") == 0) {
	    if (!handleTEARDOWNResponse(*foundRequest->session(), *foundRequest->subsession())) break;
	  } else if (strcmp(foundRequest->commandName(), "GET_PARAMETER") == 0) {
	    if (!handleGET_PARAMETERResponse(foundRequest->contentStr(), bodyStart, responseEnd)) break;
	  }
	} else if (responseCode == 401 && handleAuthenticationFailure(wwwAuthenticateParamsStr)) {
	  // We need to resend the command, with an "Authorization:" header:
	  needToResendCommand = True;
	  
	  if (strcmp(foundRequest->commandName(), "GET") == 0) {
	    // Note: If a HTTP "GET" command (for RTSP-over-HTTP tunneling) returns "401 Unauthorized", then we resend it
	    // (with an "Authorization:" header), just as we would for a RTSP command.  However, we do so using a new TCP connection,
	    // because some servers close the original connection after returning the "401 Unauthorized".
	    resetTCPSockets(); // forces the opening of a new connection for the resent command
	  }
	} else if (responseCode == 301 || responseCode == 302) { // redirection
	  resetTCPSockets(); // because we need to connect somewhere else next
	  needToResendCommand = True;
	}
	
	if (needToResendCommand) {
	  resetResponseBuffer();
	  (void)resendCommand(foundRequest);
	  delete[] headerDataCopy;
	  return; // without calling our response handler; the response to the resent command will do that
	}
      }
      
      responseSuccess = True;
    } while (0);
    
    // If we have a handler function for this response, call it.
    // But first, reset our response buffer, in case the handler goes to the event loop, and we end up getting called recursively:
    if (numExtraBytesAfterResponse > 0) {
      // An unusual case; usually due to having received pipelined responses.  Move the extra bytes to the front of the buffer:
      char* responseEnd = &fResponseBuffer[fResponseBytesAlreadySeen - numExtraBytesAfterResponse];
      
      // But first: A hack to save a copy of the response 'body', in case it's needed below for "resultString":
      numBodyBytes -= numExtraBytesAfterResponse;
      if (numBodyBytes > 0) {
	char saved = *responseEnd;
	*responseEnd = '\0';
	bodyStart = strDup(bodyStart);
	*responseEnd = saved;
      }
      
      memmove(fResponseBuffer, responseEnd, numExtraBytesAfterResponse);
      fResponseBytesAlreadySeen = numExtraBytesAfterResponse;
      fResponseBufferBytesLeft = responseBufferSize - numExtraBytesAfterResponse;
      fResponseBuffer[numExtraBytesAfterResponse] = '\0';
    } else {
      resetResponseBuffer();
    }
    if (foundRequest != NULL && foundRequest->handler() != NULL) {
      int resultCode;
      char* resultString;
      if (responseSuccess) {
	if (responseCode == 200) {
	  resultCode = 0;
	  resultString = numBodyBytes > 0 ? strDup(bodyStart) : strDup(publicParamsStr);
          // Note: The "strDup(bodyStart)" call assumes that the body is encoded without interior '\0' bytes
	} else {
	  resultCode = responseCode;
	  resultString = strDup(responseStr);
	  envir().setResultMsg(responseStr);
	}
	(*foundRequest->handler())(this, resultCode, resultString);
      } else {
	// An error occurred parsing the response, so call the handler, indicating an error:
	handleRequestError(foundRequest);
      }
    }
    delete foundRequest;
    delete[] headerDataCopy;
    if (numExtraBytesAfterResponse > 0 && numBodyBytes > 0) delete[] bodyStart;
  } while (numExtraBytesAfterResponse > 0 && responseSuccess);
}

int RTSPClient::write(const char* data, unsigned count) {
      if (fTLS.isNeeded) {
	return fTLS.write(data, count);
      } else {
	return send(fOutputSocketNum, data, count, 0);
      }
}

int RTSPClient::read(u_int8_t* buffer, unsigned bufferSize) {
  if (fTLS.isNeeded) {
    return fTLS.read(buffer, bufferSize);
  } else {
    struct sockaddr_in dummy; // 'from' address - not used
    return readSocket(envir(), fInputSocketNum, buffer, bufferSize, dummy);
  }
}


////////// RTSPClient::RequestRecord implementation //////////

RTSPClient::RequestRecord::RequestRecord(unsigned cseq, char const* commandName, responseHandler* handler,
					 MediaSession* session, MediaSubsession* subsession, u_int32_t booleanFlags,
					 double start, double end, float scale, char const* contentStr)
  : fNext(NULL), fCSeq(cseq), fCommandName(commandName), fSession(session), fSubsession(subsession), fBooleanFlags(booleanFlags),
    fStart(start), fEnd(end), fAbsStartTime(NULL), fAbsEndTime(NULL), fScale(scale), fContentStr(strDup(contentStr)), fHandler(handler) {
}

RTSPClient::RequestRecord::RequestRecord(unsigned cseq, responseHandler* handler,
					 char const* absStartTime, char const* absEndTime, float scale,
					 MediaSession* session, MediaSubsession* subsession)
  : fNext(NULL), fCSeq(cseq), fCommandName("PLAY"), fSession(session), fSubsession(subsession), fBooleanFlags(0),
    fStart(0.0f), fEnd(-1.0f), fAbsStartTime(strDup(absStartTime)), fAbsEndTime(strDup(absEndTime)), fScale(scale),
    fContentStr(NULL), fHandler(handler) {
}

RTSPClient::RequestRecord::~RequestRecord() {
  // Delete the rest of the list first:
  delete fNext;

  delete[] fAbsStartTime; delete[] fAbsEndTime;
  delete[] fContentStr;
}


////////// RTSPClient::RequestQueue implementation //////////

RTSPClient::RequestQueue::RequestQueue()
  : fHead(NULL), fTail(NULL) {
}

RTSPClient::RequestQueue::RequestQueue(RequestQueue& origQueue)
  : fHead(NULL), fTail(NULL) {
  RequestRecord* request;
  while ((request = origQueue.dequeue()) != NULL) {
    enqueue(request);
  }
}

RTSPClient::RequestQueue::~RequestQueue() {
  reset();
}

void RTSPClient::RequestQueue::enqueue(RequestRecord* request) {
  if (fTail == NULL) {
    fHead = request;
  } else {
    fTail->next() = request;
  }
  fTail = request;
}

RTSPClient::RequestRecord* RTSPClient::RequestQueue::dequeue() {
  RequestRecord* request = fHead;
  if (fHead == fTail) {
    fHead = NULL;
    fTail = NULL;
  } else {
    fHead = fHead->next();
  }
  if (request != NULL) request->next() = NULL;
  return request;
}

void RTSPClient::RequestQueue::putAtHead(RequestRecord* request) {
  request->next() = fHead;
  fHead = request;
  if (fTail == NULL) {
    fTail = request;
  }
}

RTSPClient::RequestRecord* RTSPClient::RequestQueue::findByCSeq(unsigned cseq) {
  RequestRecord* request;
  for (request = fHead; request != NULL; request = request->next()) {
    if (request->cseq() == cseq) return request;
  }
  return NULL;
}

void RTSPClient::RequestQueue::reset() {
  delete fHead;
  fHead = fTail = NULL;
}


#ifndef OMIT_REGISTER_HANDLING
////////// HandlerServerForREGISTERCommand implementation /////////

HandlerServerForREGISTERCommand* HandlerServerForREGISTERCommand
::createNew(UsageEnvironment& env, onRTSPClientCreationFunc* creationFunc, Port ourPort,
	    UserAuthenticationDatabase* authDatabase, int verbosityLevel, char const* applicationName) {
  int ourSocket = setUpOurSocket(env, ourPort);
  if (ourSocket == -1) return NULL;

  return new HandlerServerForREGISTERCommand(env, creationFunc, ourSocket, ourPort, authDatabase, verbosityLevel, applicationName);
}

HandlerServerForREGISTERCommand
::HandlerServerForREGISTERCommand(UsageEnvironment& env, onRTSPClientCreationFunc* creationFunc, int ourSocket, Port ourPort,
                                  UserAuthenticationDatabase* authDatabase, int verbosityLevel, char const* applicationName)
  : RTSPServer(env, ourSocket, ourPort, authDatabase, 30/*small reclamationTestSeconds*/),
    fCreationFunc(creationFunc), fVerbosityLevel(verbosityLevel), fApplicationName(strDup(applicationName)) {
}

HandlerServerForREGISTERCommand::~HandlerServerForREGISTERCommand() {
  delete[] fApplicationName;
}

RTSPClient* HandlerServerForREGISTERCommand
::createNewRTSPClient(char const* rtspURL, int verbosityLevel, char const* applicationName, int socketNumToServer) {
  // Default implementation: create a basic "RTSPClient":
  return RTSPClient::createNew(envir(), rtspURL, verbosityLevel, applicationName, 0, socketNumToServer);
}

char const* HandlerServerForREGISTERCommand::allowedCommandNames() {
  return "OPTIONS, REGISTER";
}

Boolean HandlerServerForREGISTERCommand
::weImplementREGISTER(char const* cmd/*"REGISTER" or "DEREGISTER"*/,
		      char const* /*proxyURLSuffix*/, char*& responseStr) {
  responseStr = NULL;
  // By default, we implement only "REGISTER"; not "DEREGISTER".  Subclass to implement "DEREGISTER"
  return strcmp(cmd, "REGISTER") == 0;
}

void HandlerServerForREGISTERCommand
::implementCmd_REGISTER(char const* cmd/*"REGISTER" or "DEREGISTER"*/,
			char const* url, char const* urlSuffix, int socketToRemoteServer,
			Boolean deliverViaTCP, char const* /*proxyURLSuffix*/) {
  if (strcmp(cmd, "REGISTER") == 0) { // By default, we don't implement "DEREGISTER"
    // Create a new "RTSPClient" object, and call our 'creation function' with it:
    RTSPClient* newRTSPClient = createNewRTSPClient(url, fVerbosityLevel, fApplicationName, socketToRemoteServer);

    if (fCreationFunc != NULL) (*fCreationFunc)(newRTSPClient, deliverViaTCP);
  }
}
#endif