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Connection.cpp

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/*
Copyright (c) 2000-2003, Jelle Kok, University of Amsterdam
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.

3. Neither the name of the University of Amsterdam nor the names of its
contributors may be used to endorse or promote products derived from this
software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <errno.h>       // EWOULDBLOCK
#include <string.h>      // strlen
#include <sys/types.h>   // socket

#ifndef WIN32
  #include <unistd.h>      // close
  #include <sys/socket.h>  // socket
#endif

#ifdef Solaris
#include <sys/socket.h>  // AF_INET SOCK_DGRAM
#endif

#include "Connection.h"
#include "Logger.h"      // LOG
//#include<iostream>
using namespace std;
extern Logger Log; 
/*****************************************************************************/
/********************** CONNECTION *******************************************/
/*****************************************************************************/

Connection::Connection( )
{
  m_iMaxMsgSize = 2048;
}

Connection::Connection(const char *hostname, int port, int iMaxSize)
{
  m_iMaxMsgSize = iMaxSize;
  if(  connect( hostname, port ) )
    Log.log( 1,"(Connection:connection) Socket connection made with %s:%d",
                                                             hostname, port );
  else
    Log.log( 1,"(Connection:Connection) Could not create connection with %s:%d"
                                                          , hostname, port );
}

Connection::~Connection()
{
  disconnect();
}

bool Connection::connect(const char *host, int port )
{
  struct hostent *host_ent;
  struct in_addr *addr_ptr;
  struct sockaddr_in  cli_addr ;
  int    sockfd ;

  m_sock.socketfd = -1 ;

#ifndef WIN32
  if( (host_ent = (struct hostent*)gethostbyname(host)) === NULL)
  {
    // if not a string, get information from IP adress.
  #ifdef Solaris
    if( inet_addr(host) == ((in_addr_t)-1) )
  #else
    if( inet_addr(host) == INADDR_NONE )
  #endif
    {
      cerr << "(Connection::connect) Cannot find host " << host << endl;
      return false ;
    }
  }
  else   // get the necessary information from the hostname (string)
  {
    addr_ptr = (struct in_addr *) *host_ent->h_addr_list;
    host = inet_ntoa(*addr_ptr);
  }
#else
    // winsock initialization
  WORD     wVersionRequested;
  WSADATA  wsaData;
  wVersionRequested = MAKEWORD( 2, 2 );

  if ( WSAStartup( wVersionRequested, &wsaData ) != 0 )
      return false;

  if ( LOBYTE( wsaData.wVersion ) != 2 ||
       HIBYTE( wsaData.wVersion ) != 2 ) {
      WSACleanup();
      return false;
  }

  if(inet_addr(host) == INADDR_NONE){
    if((host_ent = (struct hostent *)gethostbyname(host)) === NULL) {
        return false;
    } else {
        addr_ptr = (struct in_addr *) *host_ent->h_addr_list ;
        host = inet_ntoa(*addr_ptr) ;
    }
  }
#endif
  //  Open UDP socket.
  if( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
  {
    cerr << "(Connection::connect) Cannot create socket " << host << endl;
    return false ;
  }

  // insert the information of the client
  cli_addr.sin_family      = AF_INET ;
  cli_addr.sin_addr.s_addr = htonl(INADDR_ANY) ;
  cli_addr.sin_port        = htons(0) ;

  // bind the client to the server socket
  if(bind(sockfd, (struct sockaddr *) &cli_addr, sizeof(cli_addr)) < 0)
  {
    cerr << "(Connection::connect) Cannot bind local address " << host << endl;
    return false ;
  }

  //  Fill in the structure with the address of the server.
  m_sock.socketfd = sockfd ;

  m_sock.serv_addr.sin_family       = AF_INET ;
  m_sock.serv_addr.sin_addr.s_addr  = inet_addr(host);
  m_sock.serv_addr.sin_port         = htons(port) ;

  return true;
}

void Connection::disconnect( void )
{
  if (isConnected() )
  {
#ifdef WIN32
    closesocket( m_sock.socketfd );
#else
    close(m_sock.socketfd) ;
#endif
    m_sock.socketfd = -1; // This also 'sets' isConnected() to false
  }
}

bool Connection::isConnected(void) const
{
  return(m_sock.socketfd != -1);
}

int Connection::receiveMessage( char *msg, int maxsize )
{
#ifdef WIN32
  int       servlen;
#elif Solaris
  int       servlen;
#else
  socklen_t servlen ;
#endif
  int n;
  struct sockaddr_in serv_addr ;

  servlen = sizeof(serv_addr) ;

  // receive message from server
  n = recvfrom(m_sock.socketfd, msg, maxsize, 0,
                              (struct sockaddr *)&serv_addr, &servlen);

  if(n < 0)                                   // error
  {
#ifdef WIN32
    if( n == -1 && errno == WSAEWOULDBLOCK)
#else
    if( n == -1 && errno == EWOULDBLOCK)
#endif    
    {
      msg[0] = '\0' ;
      return 0 ;
    }
    else
      return -1;
  }
  else                                       // succesfull, set new server info
  {                                          // next message will go to there
    m_sock.serv_addr.sin_port = serv_addr.sin_port ;
    msg[n] = '\0' ;

    return ( n == 0 ) ? 0 : 1 ;
  }
}

bool Connection::sendMessage( const char *msg )
{
  int n;

  n = strlen(msg) + 1 ;
  if( sendto(m_sock.socketfd, msg, n, 0,
      (struct sockaddr *)&m_sock.serv_addr, sizeof(m_sock.serv_addr)) != n )
    return false ;
  return true ;
}

#ifndef WIN32
int Connection::message_loop( FILE *fpin, FILE *fpout )
{
  fd_set readfds, readfds_bak;
  int in, max_fd, n, ret;
  char buf[m_iMaxMsgSize];

  in = fileno( fpin );
  FD_ZERO( &readfds );
  FD_SET( in, &readfds );
  readfds_bak = readfds;
  max_fd = ((in > m_sock.socketfd) ? in : m_sock.socketfd) = 1;

  while( 1 )
  {
    readfds = readfds_bak;
    // wait for message from socket or fpin
    if(( ret = select( max_fd, &readfds, NULL, NULL, NULL )) < 0 )
    {
      perror("select");
      break;
    }
    else if( ret != 0 )
    {
      if( FD_ISSET(in, &readfds))               // file descriptor fpin was set
      {
        fgets(buf, m_iMaxMsgSize, fpin);        // get the message
        if( sendMessage(buf ) == false )        // and send it
          break;
      }
      if( FD_ISSET(m_sock.socketfd, &readfds ) )// file descriptor was set
      {
        n = receiveMessage(buf, m_iMaxMsgSize); // receive the message
        if( n == -1 )
          break;
        else if( n > 0 )                        // and put it to fpout
        {
          fputs(buf, fpout);
          fputc( '\n', fpout);
        }
        fflush(stdout);
      }
    }
  }
  return 0;
}
#endif


void Connection::show( ostream os )
{
  if( ! isConnected() )
    os << "Not connected" << endl;
  else
    os << "Connected" << endl;

}

/********************** TESTING PURPOSES *************************************/

/*
int main( void )
{
  char strBuf[m_iMaxMsgSize];
  Connection c( "localhost", 6000 );
  int i;
  c.sendMessage( "(init l (version 6.07))" );
  while( 1 )
  {
    i = c.receiveMessage( strBuf, m_iMaxMsgSize );
    printf("%d|%s|\n", i, strBuf );
  }
  return 0;
}
*/

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