sipclient.cpp

流媒体传输协议的实现代码,非常有用.可以支持rtsp mms等流媒体传输协议

/**********
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 2.1 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.,
59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**********/
// "liveMedia"
// Copyright (c) 1996-2004 Live Networks, Inc.  All rights reserved.
// A generic SIP client
// Implementation

#include "SIPClient.hh"
#include "GroupsockHelper.hh"

#if defined(__WIN32__) || defined(_WIN32) || defined(_QNX4)
#define _strncasecmp _strnicmp
#else
#define _strncasecmp strncasecmp
#endif

////////// SIPClient //////////

SIPClient* SIPClient
::createNew(UsageEnvironment& env,
	    unsigned char desiredAudioRTPPayloadFormat,
	    char const* mimeSubtype,
	    int verbosityLevel, char const* applicationName) {
  return new SIPClient(env, desiredAudioRTPPayloadFormat, mimeSubtype,
		       verbosityLevel, applicationName);
}

SIPClient::SIPClient(UsageEnvironment& env,
		     unsigned char desiredAudioRTPPayloadFormat,
		     char const* mimeSubtype,
		     int verbosityLevel, char const* applicationName)
  : Medium(env),
    fT1(500000 /* 500 ms */),
    fDesiredAudioRTPPayloadFormat(desiredAudioRTPPayloadFormat),
    fVerbosityLevel(verbosityLevel),
    fCSeq(0), fURL(NULL), fURLSize(0),
    fToTagStr(NULL), fToTagStrSize(0),
    fUserName(NULL), fUserNameSize(0),
    fInviteSDPDescription(NULL), fInviteCmd(NULL), fInviteCmdSize(0){
  if (mimeSubtype == NULL) mimeSubtype = "";
  fMIMESubtype = strDup(mimeSubtype);
  fMIMESubtypeSize = strlen(fMIMESubtype);

  if (applicationName == NULL) applicationName = "";
  fApplicationName = strDup(applicationName);
  fApplicationNameSize = strlen(fApplicationName);

  struct in_addr ourAddress;
  ourAddress.s_addr = ourSourceAddressForMulticast(env); // hack
  fOurAddressStr = strDup(our_inet_ntoa(ourAddress));
  fOurAddressStrSize = strlen(fOurAddressStr);

  fOurSocket = new Groupsock(env, ourAddress, 0, 255);
  if (fOurSocket == NULL) {
    env << "ERROR: Failed to create socket for addr "
	<< our_inet_ntoa(ourAddress) << ": "
	<< env.getResultMsg() << "\n";
  }

  // Now, find out our source port number.  Hack: Do this by first trying to
  // send a 0-length packet, so that the "getSourcePort()" call will work.
  fOurSocket->output(envir(), 255, (unsigned char*)"", 0);
  Port srcPort(0);
  getSourcePort(env, fOurSocket->socketNum(), srcPort);
  if (srcPort.num() != 0) {
    fOurPortNum = ntohs(srcPort.num());
  } else {
    // No luck.  Try again using a default port number:
    fOurPortNum = 5060;
    delete fOurSocket;
    fOurSocket = new Groupsock(env, ourAddress, fOurPortNum, 255);
    if (fOurSocket == NULL) {
      env << "ERROR: Failed to create socket for addr "
	  << our_inet_ntoa(ourAddress) << ", port "
	  << fOurPortNum << ": "
	  << env.getResultMsg() << "\n";
    }
  }
      
  // Set various headers to be used in each request:
  char const* formatStr;
  unsigned headerSize;

  // Set the "User-Agent:" header:
  char const* const libName = "LIVE.COM 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 = ")";
  }
  formatStr = "User-Agent: %s%s%s%s%s\r\n";
  headerSize
    = strlen(formatStr) + fApplicationNameSize + strlen(libPrefix)
    + strlen(libName) + strlen(libVersionStr) + strlen(libSuffix);
  fUserAgentHeaderStr = new char[headerSize];
  sprintf(fUserAgentHeaderStr, formatStr,
	  applicationName, libPrefix, libName, libVersionStr, libSuffix);
  fUserAgentHeaderStrSize = strlen(fUserAgentHeaderStr);

  reset();
}

SIPClient::~SIPClient() {
  reset();

  delete[] fUserAgentHeaderStr;
  delete fOurSocket;
  delete[] (char*)fOurAddressStr;
  delete[] (char*)fApplicationName;
  delete[] (char*)fMIMESubtype;
}

void SIPClient::reset() {
  fWorkingAuthenticator = NULL;
  delete[] fInviteCmd; fInviteCmd = NULL; fInviteCmdSize = 0;
  delete[] fInviteSDPDescription; fInviteSDPDescription = NULL;

  delete[] (char*)fUserName; fUserName = strDup(fApplicationName);
  fUserNameSize = strlen(fUserName);

  fValidAuthenticator.reset();

  delete[] (char*)fToTagStr; fToTagStr = NULL; fToTagStrSize = 0;
  fServerPortNum = 0;
  fServerAddress.s_addr = 0;
  delete[] (char*)fURL; fURL = NULL; fURLSize = 0;
}

void SIPClient::setProxyServer(unsigned proxyServerAddress,
			       portNumBits proxyServerPortNum) {
  fServerAddress.s_addr = proxyServerAddress;
  fServerPortNum = proxyServerPortNum;
  if (fOurSocket != NULL) {
    fOurSocket->changeDestinationParameters(fServerAddress,
					    fServerPortNum, 255);
  }
}

static char* getLine(char* startOfLine) {
  // returns the start of the next line, or NULL if none
  for (char* ptr = startOfLine; *ptr != '\0'; ++ptr) {
    if (*ptr == '\r' || *ptr == '\n') {
      // We found the end of the line
      *ptr++ = '\0';
      if (*ptr == '\n') ++ptr;
      return ptr;
    }
  }

  return NULL;
}

char* SIPClient::invite(char const* url, Authenticator* authenticator) {
  // First, check whether "url" contains a username:password to be used:
  fInviteStatusCode = 0;
  char* username; char* password;
  if (authenticator == NULL
      && parseSIPURLUsernamePassword(url, username, password)) {
    char* result = inviteWithPassword(url, username, password);
    delete[] username; delete[] password; // they were dynamically allocated
    return result;
  }

  if (!processURL(url)) return NULL;

  delete[] (char*)fURL; fURL = strDup(url);
  fURLSize = strlen(fURL);

  fCallId = our_random();
  fFromTag = our_random();

  return invite1(authenticator);
}

char* SIPClient::invite1(Authenticator* authenticator) {
  do {
    // Send the INVITE command:

    // First, construct an authenticator string:
    fValidAuthenticator.reset();
    fWorkingAuthenticator = authenticator;
    char* authenticatorStr
      = createAuthenticatorString(fWorkingAuthenticator, "INVITE", fURL);

    // Then, construct the SDP description to be sent in the INVITE:
    char* rtpmapLine;
    unsigned rtpmapLineSize;
    if (fMIMESubtypeSize > 0) {
      char* const rtpmapFmt = 
	"a=rtpmap:%u %s/8000\r\n";
      unsigned rtpmapFmtSize = strlen(rtpmapFmt)
	+ 3 /* max char len */ + fMIMESubtypeSize;
      rtpmapLine = new char[rtpmapFmtSize];
      sprintf(rtpmapLine, rtpmapFmt,
	      fDesiredAudioRTPPayloadFormat, fMIMESubtype);
      rtpmapLineSize = strlen(rtpmapLine);
    } else {
      // Static payload type => no "a=rtpmap:" line
      rtpmapLine = strDup("");
      rtpmapLineSize = 0;
    }
    char* const inviteSDPFmt = 
      "v=0\r\n"
      "o=- %u %u IN IP4 %s\r\n"
      "s=%s session\r\n"
      "c=IN IP4 %s\r\n"
      "t=0 0\r\n"
      "m=audio %u RTP/AVP %u\r\n"
      "%s";
    unsigned inviteSDPFmtSize = strlen(inviteSDPFmt)
      + 20 /* max int len */ + 20 + fOurAddressStrSize
      + fApplicationNameSize
      + fOurAddressStrSize
      + 5 /* max short len */ + 3 /* max char len */
      + rtpmapLineSize;
    delete[] fInviteSDPDescription;
    fInviteSDPDescription = new char[inviteSDPFmtSize];
    sprintf(fInviteSDPDescription, inviteSDPFmt,
	    fCallId, fCSeq, fOurAddressStr,
	    fApplicationName,
	    fOurAddressStr,
	    fClientStartPortNum, fDesiredAudioRTPPayloadFormat,
	    rtpmapLine);
    unsigned inviteSDPSize = strlen(fInviteSDPDescription);
    delete[] rtpmapLine;

    char* const cmdFmt =
      "INVITE %s SIP/2.0\r\n"
      "From: %s <sip:%s@%s>;tag=%u\r\n"
      "Via: SIP/2.0/UDP %s:%u\r\n"
      "To: %s\r\n"
      "Contact: sip:%s@%s:%u\r\n"
      "Call-ID: %u@%s\r\n"
      "CSeq: %d INVITE\r\n"
      "Content-Type: application/sdp\r\n"
      "%s" /* Proxy-Authorization: line (if any) */
      "%s" /* User-Agent: line */
      "Content-length: %d\r\n\r\n"
      "%s";
    unsigned inviteCmdSize = strlen(cmdFmt)
      + fURLSize
      + 2*fUserNameSize + fOurAddressStrSize + 20 /* max int len */
      + fOurAddressStrSize + 5 /* max port len */
      + fURLSize
      + fUserNameSize + fOurAddressStrSize + 5
      + 20 + fOurAddressStrSize
      + 20
      + strlen(authenticatorStr)
      + fUserAgentHeaderStrSize
      + 20
      + inviteSDPSize;
    delete[] fInviteCmd; fInviteCmd = new char[inviteCmdSize];
    sprintf(fInviteCmd, cmdFmt,
	    fURL,
	    fUserName, fUserName, fOurAddressStr, fFromTag,
	    fOurAddressStr, fOurPortNum,
	    fURL,
	    fUserName, fOurAddressStr, fOurPortNum,
	    fCallId, fOurAddressStr,
	    ++fCSeq,
	    authenticatorStr,
	    fUserAgentHeaderStr,
	    inviteSDPSize,
	    fInviteSDPDescription);
    fInviteCmdSize = strlen(fInviteCmd);
    delete[] authenticatorStr;

    // Before sending the "INVITE", arrange to handle any response packets,
    // and set up timers:
    fInviteClientState = Calling;
    fEventLoopStopFlag = 0;
    TaskScheduler& sched = envir().taskScheduler(); // abbrev.
    sched.turnOnBackgroundReadHandling(fOurSocket->socketNum(),
				       &inviteResponseHandler, this);
    fTimerALen = 1*fT1; // initially
    fTimerACount = 0; // initially
    fTimerA = sched.scheduleDelayedTask(fTimerALen, timerAHandler, this);
    fTimerB = sched.scheduleDelayedTask(64*fT1, timerBHandler, this);
    fTimerD = NULL; // for now

    if (!sendINVITE()) break;

    // Enter the event loop, to handle response packets, and timeouts:
    envir().taskScheduler().doEventLoop(&fEventLoopStopFlag);

    // We're finished with this "INVITE".
    // Turn off response handling and timers:
    sched.turnOffBackgroundReadHandling(fOurSocket->socketNum());
    sched.unscheduleDelayedTask(fTimerA);
    sched.unscheduleDelayedTask(fTimerB);
    sched.unscheduleDelayedTask(fTimerD);

    // NOTE: We return the SDP description that we used in the "INVITE",
    // not the one that we got from the server.
    // ##### Later: match the codecs in the response (offer, answer) #####
    if (fInviteSDPDescription != NULL) {
      return strDup(fInviteSDPDescription);
    }
  } while (0);

  fInviteStatusCode = 2;
  return NULL;
}

void SIPClient::inviteResponseHandler(void* clientData, int /*mask*/) {
  SIPClient* client = (SIPClient*)clientData;
  unsigned responseCode = client->getResponseCode();
  client->doInviteStateMachine(responseCode);
}

// Special 'response codes' that represent timers expiring:
unsigned const timerAFires = 0xAAAAAAAA;
unsigned const timerBFires = 0xBBBBBBBB;
unsigned const timerDFires = 0xDDDDDDDD;

void SIPClient::timerAHandler(void* clientData) {
  SIPClient* client = (SIPClient*)clientData;
  if (client->fVerbosityLevel >= 1) {
    client->envir() << "RETRANSMISSION " << ++client->fTimerACount
		    << ", after " << client->fTimerALen/1000000.0
		    << " additional seconds\n";
  }
  client->doInviteStateMachine(timerAFires);
}

void SIPClient::timerBHandler(void* clientData) {
  SIPClient* client = (SIPClient*)clientData;
  if (client->fVerbosityLevel >= 1) {
    client->envir() << "RETRANSMISSION TIMEOUT, after "
		    << 64*client->fT1/1000000.0 << " seconds\n";
    fflush(stderr);
  }
  client->doInviteStateMachine(timerBFires);
}

void SIPClient::timerDHandler(void* clientData) {
  SIPClient* client = (SIPClient*)clientData;
  if (client->fVerbosityLevel >= 1) {
    client->envir() << "TIMER D EXPIRED\n";
  }
  client->doInviteStateMachine(timerDFires);
}

void SIPClient::doInviteStateMachine(unsigned responseCode) {
  // Implement the state transition diagram (RFC 3261, Figure 5)
  TaskScheduler& sched = envir().taskScheduler(); // abbrev.
  switch (fInviteClientState) {
    case Calling: {
      if (responseCode == timerAFires) {
	// Restart timer A (with double the timeout interval):
	fTimerALen *= 2;
	fTimerA
	  = sched.scheduleDelayedTask(fTimerALen, timerAHandler, this);

	fInviteClientState = Calling;
	if (!sendINVITE()) doInviteStateTerminated(0);
      } else {
	// Turn off timers A & B before moving to a new state: 
	sched.unscheduleDelayedTask(fTimerA);
	sched.unscheduleDelayedTask(fTimerB);
	
	if (responseCode == timerBFires) {
	  envir().setResultMsg("No response from server");
	  doInviteStateTerminated(0);
	} else if (responseCode >= 100 && responseCode <= 199) {
	  fInviteClientState = Proceeding;
	} else if (responseCode >= 200 && responseCode <= 299) {
	  doInviteStateTerminated(responseCode);
	} else if (responseCode >= 400 && responseCode <= 499) {
	  doInviteStateTerminated(responseCode);
	      // this isn't what the spec says, but it seems right...
	} else if (responseCode >= 300 && responseCode <= 699) {
	  fInviteClientState = Completed;
	  fTimerD
	    = sched.scheduleDelayedTask(32000000, timerDHandler, this);
	  if (!sendACK()) doInviteStateTerminated(0);
	}
      }
      break;
    }

    case Proceeding: {
      if (responseCode >= 100 && responseCode <= 199) {
	fInviteClientState = Proceeding;
      } else if (responseCode >= 200 && responseCode <= 299) {
	doInviteStateTerminated(responseCode);
      } else if (responseCode >= 400 && responseCode <= 499) {
	doInviteStateTerminated(responseCode);
	    // this isn't what the spec says, but it seems right...
      } else if (responseCode >= 300 && responseCode <= 699) {
	fInviteClientState = Completed;
	fTimerD = sched.scheduleDelayedTask(32000000, timerDHandler, this);
	if (!sendACK()) doInviteStateTerminated(0);
      }
      break;
    }

    case Completed: {
      if (responseCode == timerDFires) {
	envir().setResultMsg("Transaction terminated");
	doInviteStateTerminated(0);
      } else if (responseCode >= 300 && responseCode <= 699) {
	fInviteClientState = Completed;
	if (!sendACK()) doInviteStateTerminated(0);
      }
      break;
    }

    case Terminated: {
	doInviteStateTerminated(responseCode);
	break;
    }
  }
}

void SIPClient::doInviteStateTerminated(unsigned responseCode) {
  fInviteClientState = Terminated; // FWIW...
  if (responseCode < 200 || responseCode > 299) {
    // We failed, so return NULL;
    delete[] fInviteSDPDescription; fInviteSDPDescription = NULL;
  }

  // Unblock the event loop:
  fEventLoopStopFlag = ~0;
}

Boolean SIPClient::sendINVITE() {
  if (!sendRequest(fInviteCmd, fInviteCmdSize)) {
    envir().setResultErrMsg("INVITE send() failed: ");
    return False;
  }
  return True;
}

unsigned SIPClient::getResponseCode() {
  unsigned responseCode = 0;
  do {
    // Get the response from the server:
    unsigned const readBufSize = 10000;
    char readBuffer[readBufSize+1]; char* readBuf = readBuffer;

    char* firstLine = NULL;
    char* nextLineStart = NULL;
    unsigned bytesRead = getResponse(readBuf, readBufSize);
    if (bytesRead < 0) break;
    if (fVerbosityLevel >= 1) {
      envir() << "Received INVITE response: " << readBuf << "\n";
    }

    // Inspect the first line to get the response code:
    firstLine = readBuf;
    nextLineStart = getLine(firstLine);
    if (!parseResponseCode(firstLine, responseCode)) break;

    if (responseCode != 200) {
      if (responseCode >= 400 && responseCode <= 499
	  && fWorkingAuthenticator != NULL) {
	// We have an authentication failure, so fill in