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

	// "*fWorkingAuthenticator" using the contents of a following
	// "Proxy-Authenticate:" line.  (Once we compute a 'response' for
	// "fWorkingAuthenticator", it can be used in a subsequent request
	// - that will hopefully succeed.)
	char* lineStart;
	while (1) {
	  lineStart = nextLineStart;
	  if (lineStart == NULL) break;

	  nextLineStart = getLine(lineStart);
	  if (lineStart[0] == '\0') break; // this is a blank line

	  char* realm = strDupSize(lineStart);
	  char* nonce = strDupSize(lineStart);
	  // ##### Check for the format of "Proxy-Authenticate:" lines from
	  // ##### known server types.
	  // ##### This is a crock! We should make the parsing more general
          Boolean foundAuthenticateHeader = False;
	  if (
	      // Asterisk #####
	      sscanf(lineStart, "Proxy-Authenticate: Digest realm=\"%[^\"]\", nonce=\"%[^\"]\"",
		     realm, nonce) == 2 ||
	      // Cisco ATA #####
	      sscanf(lineStart, "Proxy-Authenticate: Digest algorithm=MD5,domain=\"%*[^\"]\",nonce=\"%[^\"]\", realm=\"%[^\"]\"",
		     nonce, realm) == 2) {
            fWorkingAuthenticator->setRealmAndNonce(realm, nonce);
            foundAuthenticateHeader = True;
          }
          delete[] realm; delete[] nonce;
          if (foundAuthenticateHeader) break;
	} 
      }
      envir().setResultMsg("cannot handle INVITE response: ", firstLine);
      break;
    }

    // Skip every subsequent header line, until we see a blank line.
    // While doing so, check for "To:" and "Content-Length:" lines.
    // The remaining data is assumed to be the SDP descriptor that we want.
    // We should really do some more checking on the headers here - e.g., to
    // check for "Content-type: application/sdp", "CSeq", etc. #####
    int contentLength = -1;
    char* lineStart;
    while (1) {
      lineStart = nextLineStart;
      if (lineStart == NULL) break;

      nextLineStart = getLine(lineStart);
      if (lineStart[0] == '\0') break; // this is a blank line

      char* toTagStr = strDupSize(lineStart);
      if (sscanf(lineStart, "To:%*[^;]; tag=%s", toTagStr) == 1) {
	delete[] (char*)fToTagStr; fToTagStr = strDup(toTagStr);
	fToTagStrSize = strlen(fToTagStr);
      }
      delete[] toTagStr;
 
      if (sscanf(lineStart, "Content-Length: %d", &contentLength) == 1
          || sscanf(lineStart, "Content-length: %d", &contentLength) == 1) {
        if (contentLength < 0) {
          envir().setResultMsg("Bad \"Content-length:\" header: \"",
                               lineStart, "\"");
          break;
        }
      }
    }

    // We're now at the end of the response header lines
    if (lineStart == NULL) {
      envir().setResultMsg("no content following header lines: ", readBuf);
      break;
    }

    // Use the remaining data as the SDP descr, but first, check
    // the "Content-length:" header (if any) that we saw.  We may need to
    // read more data, or we may have extraneous data in the buffer.
    char* bodyStart = nextLineStart;
    if (contentLength >= 0) {
      // We saw a "Content-length:" header
      unsigned numBodyBytes = &readBuf[bytesRead] - bodyStart;
      if (contentLength > (int)numBodyBytes) {
        // We need to read more data.  First, make sure we have enough
        // space for it:
        unsigned numExtraBytesNeeded = contentLength - numBodyBytes;
#ifdef USING_TCP
	// THIS CODE WORKS ONLY FOR TCP: #####
        unsigned remainingBufferSize
          = readBufSize - (bytesRead + (readBuf - readBuffer));
        if (numExtraBytesNeeded > remainingBufferSize) {
          char tmpBuf[200];
          sprintf(tmpBuf, "Read buffer size (%d) is too small for \"Content-length:\" %d (need a buffer size of >= %d bytes\n",
                  readBufSize, contentLength,
                  readBufSize + numExtraBytesNeeded - remainingBufferSize);
          envir().setResultMsg(tmpBuf);
          break;
        }

        // Keep reading more data until we have enough:
        if (fVerbosityLevel >= 1) {
          envir() << "Need to read " << numExtraBytesNeeded
		  << " extra bytes\n";
        }
        while (numExtraBytesNeeded > 0) {
          char* ptr = &readBuf[bytesRead];
	  unsigned bytesRead2;
	  struct sockaddr_in fromAddr;
	  Boolean readSuccess
	    = fOurSocket->handleRead((unsigned char*)ptr,
				     numExtraBytesNeeded,
				     bytesRead2, fromAddr);
          if (!readSuccess) break;
          ptr[bytesRead2] = '\0';
          if (fVerbosityLevel >= 1) {
            envir() << "Read " << bytesRead2
		    << " extra bytes: " << ptr << "\n";
          }

          bytesRead += bytesRead2;
          numExtraBytesNeeded -= bytesRead2;
        }
#endif
        if (numExtraBytesNeeded > 0) break; // one of the reads failed
      }

      bodyStart[contentLength] = '\0'; // trims any extra data
    }
  } while (0);

  return responseCode;
}

char* SIPClient::inviteWithPassword(char const* url, char const* username,
				    char const* password) {
  delete[] (char*)fUserName; fUserName = strDup(username);
  fUserNameSize = strlen(fUserName);

  Authenticator authenticator;
  authenticator.setUsernameAndPassword(username, password);
  char* inviteResult = invite(url, &authenticator);
  if (inviteResult != NULL) {
    // We are already authorized
    return inviteResult;
  }

  // The "realm" and "nonce" fields should have been filled in:
  if (authenticator.realm() == NULL || authenticator.nonce() == NULL) {
    // We haven't been given enough information to try again, so fail:
    return NULL;
  }

  // Try again (but with the same CallId):
  inviteResult = invite1(&authenticator);
  if (inviteResult != NULL) {
    // The authenticator worked, so use it in future requests:
    fValidAuthenticator = authenticator;
  }

  return inviteResult;
}

Boolean SIPClient::sendACK() {
  char* cmd = NULL;
  do {
    char* const cmdFmt =
      "ACK %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;tag=%s\r\n"
      "Call-ID: %u@%s\r\n"
      "CSeq: %d ACK\r\n"
      "Content-length: 0\r\n\r\n";
    unsigned cmdSize = strlen(cmdFmt)
      + fURLSize
      + 2*fUserNameSize + fOurAddressStrSize + 20 /* max int len */
      + fOurAddressStrSize + 5 /* max port len */
      + fURLSize + fToTagStrSize
      + 20 + fOurAddressStrSize
      + 20;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    fURL,
	    fUserName, fUserName, fOurAddressStr, fFromTag,
	    fOurAddressStr, fOurPortNum,
	    fURL, fToTagStr,
	    fCallId, fOurAddressStr,
	    fCSeq /* note: it's the same as before; not incremented */);
    
    if (!sendRequest(cmd, strlen(cmd))) {
      envir().setResultErrMsg("ACK send() failed: ");
      break;
    }

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

  delete[] cmd;
  return False;
}

Boolean SIPClient::sendBYE() {
  // NOTE: This should really be retransmitted, for reliability #####
  char* cmd = NULL;
  do {
    char* const cmdFmt =
      "BYE %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;tag=%s\r\n"
      "Call-ID: %u@%s\r\n"
      "CSeq: %d ACK\r\n"
      "Content-length: 0\r\n\r\n";
    unsigned cmdSize = strlen(cmdFmt)
      + fURLSize
      + 2*fUserNameSize + fOurAddressStrSize + 20 /* max int len */
      + fOurAddressStrSize + 5 /* max port len */
      + fURLSize + fToTagStrSize
      + 20 + fOurAddressStrSize
      + 20;
    cmd = new char[cmdSize];
    sprintf(cmd, cmdFmt,
	    fURL,
	    fUserName, fUserName, fOurAddressStr, fFromTag,
	    fOurAddressStr, fOurPortNum,
	    fURL, fToTagStr,
	    fCallId, fOurAddressStr,
	    ++fCSeq);
    
    if (!sendRequest(cmd, strlen(cmd))) {
      envir().setResultErrMsg("BYE send() failed: ");
      break;
    }

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

  delete[] cmd;
  return False;
}

Boolean SIPClient::processURL(char const* url) {
  do {
    // If we don't already have a server address/port, then
    // get these by parsing the URL:
    if (fServerAddress.s_addr == 0) {
      NetAddress destAddress;
      if (!parseSIPURL(envir(), url, destAddress, fServerPortNum)) break;
      fServerAddress.s_addr = *(unsigned*)(destAddress.data());
    
      if (fOurSocket != NULL) {
	fOurSocket->changeDestinationParameters(fServerAddress,
						fServerPortNum, 255);
      }
    }

    return True; 
  } while (0);

  fInviteStatusCode = 1;
  return False;
}

Boolean SIPClient::parseSIPURL(UsageEnvironment& env, char const* url,
			       NetAddress& address,
			       portNumBits& portNum) {
  do {
    // Parse the URL as "sip:<username>@<address>:<port>/<etc>"
    // (with ":<port>" and "/<etc>" optional)
    // Also, skip over any "<username>[:<password>]@" preceding <address>
    char const* prefix = "sip:";
    unsigned const prefixLength = 4;
    if (_strncasecmp(url, prefix, prefixLength) != 0) {
      env.setResultMsg("URL is not of the form \"", prefix, "\"");
      break;
    }

    unsigned const parseBufferSize = 100;
    char parseBuffer[parseBufferSize];
    unsigned addressStartIndex = prefixLength;
    while (url[addressStartIndex] != '\0'
	   && url[addressStartIndex++] != '@') {}
    char const* from = &url[addressStartIndex];

    // Skip over any "<username>[:<password>]@"
    char const* from1 = from;
    while (*from1 != '\0' && *from1 != '/') {
      if (*from1 == '@') {
	from = ++from1;
	break;
      }
      ++from1;
    }

    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) {
      env.setResultMsg("URL is too long");
      break;
    }

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

    portNum = 5060; // default value
    char nextChar = *from;
    if (nextChar == ':') {
      int portNumInt;
      if (sscanf(++from, "%d", &portNumInt) != 1) {
	env.setResultMsg("No port number follows ':'");
	break;
      }
      if (portNumInt < 1 || portNumInt > 65535) {
	env.setResultMsg("Bad port number");
	break;
      }
      portNum = (portNumBits)portNumInt;
    }

    return True;
  } while (0);

  return False;
}

Boolean SIPClient::parseSIPURLUsernamePassword(char const* url,
					       char*& username,
					       char*& password) {
  username = password = NULL; // by default
  do {
    // Parse the URL as "sip:<username>[:<password>]@<whatever>"
    char const* prefix = "sip:";
    unsigned const prefixLength = 4;
    if (_strncasecmp(url, prefix, prefixLength) != 0) break;

    // Look for the ':' and '@':
    unsigned usernameIndex = prefixLength;
    unsigned colonIndex = 0, atIndex = 0;
    for (unsigned i = usernameIndex; url[i] != '\0' && url[i] != '/'; ++i) {
      if (url[i] == ':' && colonIndex == 0) {
	colonIndex = i;
      } else if (url[i] == '@') {
        atIndex = i;
        break; // we're done
      }
    }
    if (atIndex == 0) break; // no '@' found

    char* urlCopy = strDup(url);
    urlCopy[atIndex] = '\0';
    if (colonIndex > 0) {
      urlCopy[colonIndex] = '\0';
      password = strDup(&urlCopy[colonIndex+1]);
    } else {
      password = strDup("");
    }
    username = strDup(&urlCopy[usernameIndex]);
    delete[] urlCopy;

    return True;
  } while (0);

  return False;
}

char*
SIPClient::createAuthenticatorString(Authenticator const* authenticator,
				      char const* cmd, char const* url) {
  if (authenticator != NULL && authenticator->realm() != NULL
      && authenticator->nonce() != NULL && authenticator->username() != NULL
      && authenticator->password() != NULL) {
    // We've been provided a filled-in authenticator, so use it:
    char* const authFmt = "Proxy-Authorization: Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", response=\"%s\", uri=\"%s\"\r\n";
    char const* response = authenticator->computeDigestResponse(cmd, url);
    unsigned authBufSize = strlen(authFmt)
      + strlen(authenticator->username()) + strlen(authenticator->realm())
      + strlen(authenticator->nonce()) + strlen(url) + strlen(response);
    char* authenticatorStr = new char[authBufSize];
    sprintf(authenticatorStr, authFmt,
	    authenticator->username(), authenticator->realm(),
	    authenticator->nonce(), response, url);
    authenticator->reclaimDigestResponse(response);

    return authenticatorStr;
  }

  return strDup("");
}

Boolean SIPClient::sendRequest(char const* requestString,
			       unsigned requestLength) {
  if (fVerbosityLevel >= 1) {
    envir() << "Sending request: " << requestString << "\n";
  }
  // NOTE: We should really check that "requestLength" is not #####
  // too large for UDP (see RFC 3261, section 18.1.1) #####
  return fOurSocket->output(envir(), 255, (unsigned char*)requestString,
			    requestLength);
}

unsigned SIPClient::getResponse(char*& responseBuffer,
				unsigned responseBufferSize) {
  if (responseBufferSize == 0) return 0; // just in case...
  responseBuffer[0] = '\0'; // ditto

  // Keep reading data from the socket until we see "\r\n\r\n" (except
  // at the start), or until we fill up our buffer.
  // Don't read any more than this.
  char* p = responseBuffer;
  Boolean haveSeenNonCRLF = False;
  int bytesRead = 0;
  while (bytesRead < (int)responseBufferSize) {
    unsigned bytesReadNow;
    struct sockaddr_in fromAddr;
    unsigned char* toPosn = (unsigned char*)(responseBuffer+bytesRead);
    Boolean readSuccess
      = fOurSocket->handleRead(toPosn, responseBufferSize-bytesRead,
			       bytesReadNow, fromAddr);
    if (!readSuccess || bytesReadNow == 0) {
      envir().setResultMsg("SIP response was truncated");
      break;
    }
    bytesRead += bytesReadNow;
    
    // Check whether we have "\r\n\r\n":
    char* lastToCheck = responseBuffer+bytesRead-4;
    if (lastToCheck < responseBuffer) continue;
    for (; p <= lastToCheck; ++p) {
      if (haveSeenNonCRLF) {
        if (*p == '\r' && *(p+1) == '\n' &&
            *(p+2) == '\r' && *(p+3) == '\n') {
          responseBuffer[bytesRead] = '\0';

          // Before returning, trim any \r or \n from the start:
          while (*responseBuffer == '\r' || *responseBuffer == '\n') {
            ++responseBuffer;
            --bytesRead;
          }
          return bytesRead;
        }
      } else {
        if (*p != '\r' && *p != '\n') {
          haveSeenNonCRLF = True;
        }
      }
    }
  }
  
  return 0;
}

Boolean SIPClient::parseResponseCode(char const* line, 
				      unsigned& responseCode) {
  if (sscanf(line, "%*s%u", &responseCode) != 1) {
    envir().setResultMsg("no response code in line: \"", line, "\"");
    return False;
  }

  return True;
}