Live555 RTSPServer 分析

 

 

createNew

RTSPServer*
RTSPServer::createNew(UsageEnvironment& env, Port ourPort,
		    UserAuthenticationDatabase* authDatabase,
		    unsigned reclamationTestSeconds) 

{
  int ourSocket = setUpOurSocket(env, ourPort);//创建套接字
  if (ourSocket == -1) return NULL;

  return new RTSPServer(env, ourSocket, ourPort, authDatabase, reclamationTestSeconds);//建立RTP服务器
}

RTSPServer: 套接字和连接处理函数（incomingConnectionHandlerRTSP）相绑定

RTSPServer::RTSPServer(UsageEnvironment& env,
		       int ourSocket, Port ourPort,
		       UserAuthenticationDatabase* authDatabase,
		       unsigned reclamationTestSeconds)
  : Medium(env),
    fRTSPServerSocket(ourSocket), fRTSPServerPort(ourPort), fHTTPServerSocket(-1), fHTTPServerPort(0),
    fServerMediaSessions(HashTable::create(STRING_HASH_KEYS)),
    fClientConnections(HashTable::create(ONE_WORD_HASH_KEYS)),
    fClientConnectionsForHTTPTunneling(NULL), // will get created if needed
    fClientSessions(HashTable::create(STRING_HASH_KEYS)),
    fAuthDB(authDatabase), fReclamationTestSeconds(reclamationTestSeconds) 

{
  ignoreSigPipeOnSocket(ourSocket); // so that clients on the same host that are killed don't also kill us

  // Arrange to handle connections from others:

  /*任务调度器把socket句柄放入后面select调用中用到的socket句柄集(fReadSet)中，同时将socket句柄和incomingConnectionHandler句柄关联起来*/
  env.taskScheduler().turnOnBackgroundReadHandling(fRTSPServerSocket,
					(TaskScheduler::BackgroundHandlerProc*)&incomingConnectionHandlerRTSP, this);
}

class TaskScheduler 

{
    void turnOnBackgroundReadHandling(int socketNum, BackgroundHandlerProc* handlerProc, void* clientData) 

    {
       setBackgroundHandling(socketNum, SOCKET_READABLE, handlerProc, clientData);
    }
}

/*套接字和处理函数建立联系的实现*/

void BasicTaskScheduler
  ::setBackgroundHandling(int socketNum, int conditionSet, BackgroundHandlerProc* handlerProc, void* clientData) 

{
  if (socketNum < 0) return;
  FD_CLR((unsigned)socketNum, &fReadSet);
  FD_CLR((unsigned)socketNum, &fWriteSet);
  FD_CLR((unsigned)socketNum, &fExceptionSet);
  if (conditionSet == 0) 

  {
    fHandlers->clearHandler(socketNum);
    if (socketNum+1 == fMaxNumSockets) {
      --fMaxNumSockets;
    }
  } 

 else 

 {
    fHandlers->assignHandler(socketNum, conditionSet, handlerProc, clientData);
    if (socketNum+1 > fMaxNumSockets) {
      fMaxNumSockets = socketNum+1;
    }
    if (conditionSet&SOCKET_READABLE) FD_SET((unsigned)socketNum, &fReadSet);
    if (conditionSet&SOCKET_WRITABLE) FD_SET((unsigned)socketNum, &fWriteSet);
    if (conditionSet&SOCKET_EXCEPTION) FD_SET((unsigned)socketNum, &fExceptionSet);
  }
}

连接处理函数：

void RTSPServer::incomingConnectionHandlerRTSP(void* instance, int /*mask*/) {
  RTSPServer* server = (RTSPServer*)instance;
  server->incomingConnectionHandlerRTSP1();
}
void RTSPServer::incomingConnectionHandlerRTSP1() {
  incomingConnectionHandler(fRTSPServerSocket);
}
void RTSPServer::incomingConnectionHandler(int serverSocket) {
  struct sockaddr_in clientAddr;
  SOCKLEN_T clientAddrLen = sizeof clientAddr;
  int clientSocket = accept(serverSocket, (struct sockaddr*)&clientAddr, &clientAddrLen);
  if (clientSocket < 0) {
    int err = envir().getErrno();
    if (err != EWOULDBLOCK) {
        envir().setResultErrMsg("accept() failed: ");
    }
    return;
  }
  makeSocketNonBlocking(clientSocket);
  increaseSendBufferTo(envir(), clientSocket, 50*1024);

#ifdef DEBUG
  envir() << "accept()ed connection from " << AddressString(clientAddr).val() << "\n";
#endif

  // Create a new object for handling this RTSP connection:
  (void)createNewClientConnection(clientSocket, clientAddr);
}