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server.cpp

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#include "sysconfig.h"
#include "server.h"
#include "event.h"

Server::Server(EventQueue& r_inque, EventQueue& r_outque, Log& r_lgfile)
  : mShutdown(false), mrLog(r_lgfile),
    mrInQueue(r_inque), mrOutQueue(r_outque) {
}

Server::~Server() {
  ConnList::iterator i;
  for (i = mConns.begin(); i != mConns.end(); i++) {
    delete (*i);
  }
}

bool Server::Boot(unsigned short port) {
  // Get a TCP protocol socket for the server to listen on.
  mAcceptor = socket (AF_INET, SOCK_STREAM, 0);
  if (mAcceptor == INVALID_SOCKET) {
    ServerLog().Write("ERROR-Server(socket): %d", WSAGetLastError());
    return false;
  }

  // Set the listening socket to be non-blocking
  if (!SetNonBlocking(mAcceptor))
    return false;

  // Set up listening socket to allow local address reuse
  int sockopt_val = 1;         // Non-zero means turn on for boolean options,
                               //  some options require other types and values.
  if (setsockopt(mAcceptor, SOL_SOCKET, SO_REUSEADDR, (char *)&sockopt_val,
                 sizeof(sockopt_val)) == SOCKET_ERROR) {
    ServerLog().Write("ERROR-Server(setsockopt): %d",WSAGetLastError());
    closesocket(mAcceptor);
    return false;
  }

  // Associate our local address with this socket
  mTo.sin_family = AF_INET;    // protocol - internet
  mTo.sin_addr.s_addr = INADDR_ANY; // accept on whatever IP we're set up as
  mTo.sin_port = htons(port);   // port must be in network byte order
  if (bind(mAcceptor, (struct sockaddr *)&mTo, sizeof(mTo)) == SOCKET_ERROR) {
    ServerLog().Write("ERROR-Server(bind): %d",WSAGetLastError());
    closesocket(mAcceptor);
    return false;
  }
  // Let's start listening for incoming connections
  if (listen(mAcceptor, 5) == SOCKET_ERROR) { // Connection backlog of 5.
    ServerLog().Write("ERROR-Server(listen): %d",WSAGetLastError());
    closesocket(mAcceptor);
    return false;
  }
  /*
    mNumFds is calculated for the select() function - Windows ignores
    it as the underlying FD sets are constructed differently than Unixes
    On Unixes FDs are include all files, pipes and sockets open.
    We need to calculate the highest FD number for the Unix select.

    In bootup the highest FD is the listening socket so...
  */
  mNumFds = mAcceptor;
  return true;
}

#pragma argsused
void Server::Run(void * parms) {
  ServerLog().Write("INFO-StartServer(): Server thread entered.");
  struct timeval timeout = { 0, 1 };  // Will poll for 1 millisecond

  while (!mShutdown) {  // Loops until a SHUTDOWN_E message is received.
    ConnList::iterator i, curr;

    // Reset our socket interest set
    InitFDs();

    // Poll our socket interest set for about a millisec.
    if (select(mNumFds + 1, &mInputFDs, &mOutputFDs, NULL, &timeout) == SOCKET_ERROR) {
      ServerLog().Write("ERROR-Server(select): %d",WSAGetLastError());
      break;
    }

    // If we have incoming connections on our listening port handle them.
    if (FD_ISSET(mAcceptor, &mInputFDs)) {
      AcceptConnection();
    }

    // If we have incoming data on any connections handle it.
    for(i = mConns.begin(); i != mConns.end(); i++) {
      if (FD_ISSET((*i)->GetSocket(), &mInputFDs)) {
        (*i)->HandleInput();

        // Loop through fully formed messages (CRLF).
        string* msg = (*i)->ReadMsg();
        while(msg) {
          // notify the chat driver.
          mrOutQueue.Push(new Event(MESSAGE_E,
            (*i)->GetSocket(), msg->length(), msg->c_str()));
          delete msg; // ReadMsg creates a new string - we must delete it.
          msg = (*i)->ReadMsg();
        } // while
      } // if
    } // for

    // Process the event queue.
    ProcessQueue();

    // If we have outgoing data ready on any connections handle it.
    for(i = mConns.begin(); i != mConns.end(); i++) {
      if (FD_ISSET((*i)->GetSocket(), &mOutputFDs))
        (*i)->HandleOutput();
    }

    // Cleanup sockets that have been scheduled for disconnection.
    for(i = mConns.begin(); i != mConns.end();) {
      curr = i++;
      if ((*curr)->CanBeDisconnected()) {
        (*curr)->Disconnect();
        // Tell the chat driver about it.
        mrOutQueue.Push(new Event(DISCONNECT_E, (*curr)->GetSocket(),
          0, NULL));
        delete (*curr);
        mConns.erase(curr);
      }
    }
  } // while
  ShutdownServer();
  ServerLog().Write("INFO-StartServer(): Server thread exited.");
}

void Server::AcceptConnection() {
  struct sockaddr_in addr; // An address structure for our incoming connection.
  int addrlen = sizeof(addr);

  // Try to accept the connection
  SOCKET psock = accept(mAcceptor, (struct sockaddr *)&addr, &addrlen);
  if (psock != INVALID_SOCKET) {
    // Set the socket to non-blocking.
    if (SetNonBlocking(psock)) {
      // The socket set up correctly.  Let us add a new Connection.
      Connection *conn = new Connection(psock, this);
      ServerLog().Write("INFO-Server(accept): Connection %d accepted", psock);
      mConns.push_back(conn);  // Put it on the connection list.
      // Tell the chat server we have a new connection
      mrOutQueue.Push(new Event(CONNECT_E, conn->GetSocket(), 0, NULL));
    }
  } else {
    // Weve encountered an error during accept.
    ServerLog().Write("ERROR-ServerAccept(accept): %d", WSAGetLastError());
  }
}

void Server::InitFDs () {
  FD_ZERO (&mInputFDs);           // Clears our interest sets out.
  FD_ZERO (&mOutputFDs);

  FD_SET (mAcceptor, &mInputFDs); // Register interest in listening socket.
  for(ConnList::iterator i = mConns.begin(); i != mConns.end(); i++) {
    /*
      mNumFds is calculated for the select() function - Windows ignores
      it as the underlying FD sets are constructed differently than Unixes
      On Unixes FDs are include all files, pipes and sockets open.
      We need to calculate the highest FD number for the Unix select.
    */
    mNumFds = max(mNumFds, (*i)->GetSocket());
    FD_SET((*i)->GetSocket(), &mInputFDs);  // Always interested in input.
    if ((*i)->HasOutput())        // See [1] above.
      FD_SET((*i)->GetSocket(), &mOutputFDs);
  }
}

void Server::ProcessQueue() {
  // manage event queue
  Event* e;
  while ((e = mrInQueue.Pop()) != NULL) {
    switch (e->mEventType) {
    case DISCONNECT_E:
      // We've been told by the chat driver to kill a connection.
      {
        // Not yet implemented.
      }
      break;
    case CONNECT_E:
      // Should never happen - included for completeness
      break;
    case MESSAGE_E:
      // A message from the chat driver to route to a connection here.
      {
        // Test for null message data and ignore it
        if (e->mpData && e->mDataLen) {
          string msg;
          msg.append(e->mpData, e->mDataLen);
          for(ConnList::iterator c = mConns.begin(); c != mConns.end(); c++) {
            if ((*c)->GetSocket() == e->mClientId) {
              (*c)->SendMsg(msg);
              // Register interest as we have data ready on the wire
              FD_SET ((*c)->GetSocket(), &mOutputFDs);
            }
          }
        }
      }
      break;
    case SHUTDOWN_E:
      // We've been requested to shutdown so let's comply.
      mShutdown = true;
      break;
    case NONE_E:
      break;
    } // switch
    delete e;
  } // while
}

void Server::ShutdownServer() {
  ServerLog().Write("INFO-Server(shutdown): Server shutting down");
  ConnList::iterator ci, curr;
  for(ci = mConns.begin(); ci != mConns.end();) {
    curr = ci++;// :WARN: The list containers iterator is invalidated on erase.
                // So we need to increment it first and delete the old.
    (*curr)->Disconnect();
    // Tell chat driver about each connection as it leaves
    mrOutQueue.Push(new Event(DISCONNECT_E, (*curr)->GetSocket(),
      0, NULL));
    delete (*curr);
    mConns.erase(curr);
  }
  closesocket(mAcceptor);
  mrOutQueue.Push(new Event(SHUTDOWN_E, 0, 0, 0));
}

Log& Server::ServerLog() {
  return mrLog;
}

bool Server::SetNonBlocking(SOCKET s) {
  unsigned long ioctl_cmd = 1; // Non-zero means turn on for ioctl commands.
  if (ioctlsocket(s, FIONBIO, &ioctl_cmd) == SOCKET_ERROR) {
    ServerLog().Write("ERROR-Server(SetNonBlocking): %d on socket %d",
      WSAGetLastError(), s);
    closesocket(s);
    return false;
  }
  return true;
}

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