Networking Project 1

NetworkingProject1.cpp

// based on work from http://cs.baylor.edu/~donahoo/practical/CSockets/practical/
/*
 *   C++ sockets on Unix and Windows
 *   Copyright (C) 2002
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "PracticalSocket.h"  // For Socket and SocketException
#include <iostream>           // For cerr and cout
#include <fstream>            // For file streams
#include <sstream>            // For atoi() replacement
#include <string>             // String processing
#include <unistd.h>           // For fork()

using namespace std;

const unsigned int RCVBUFSIZE = 1024;    // Size of receive buffer

void HandleTCPClient(TCPSocket *sock, string nodeName);
unsigned short string_to_us(string instring);
void send_until_eof(TCPSocket *sock, ifstream *infile);

int main(int argc, char *argv[]) {

  string servAddress = "localhost";

  if (fork() == 0) {
    // Node A

    try {

      string current_line;
      ifstream confAFile ("confA.txt");


      getline(confAFile, current_line); // First line contains Node B port
      unsigned short nodeBPort = string_to_us(current_line);

      // Establish connection with Node B
      TCPSocket clientNodeA(servAddress, nodeBPort);

      send_until_eof(&clientNodeA, &confAFile);

    } catch(SocketException &e) {
      cerr << e.what() << endl;
      exit(1);
    }

  } else if(fork() == 0) {
    // Node B

    try {

      string current_line;
      ifstream confBFile ("confB.txt");

      getline(confBFile, current_line); // First line; contains node B port
      unsigned short nodeBPort = string_to_us(current_line);

      getline(confBFile, current_line); // Second line; contains node C port
      unsigned short nodeCPort = string_to_us(current_line);

      TCPServerSocket servNodeB(nodeBPort);     // Server Socket object
      TCPSocket clientNodeB(servAddress, nodeCPort);

      send_until_eof(&clientNodeB, &confBFile);

      // Get connection from Node A
      HandleTCPClient(servNodeB.accept(), "B");   // Wait for a client to connect

    } catch(SocketException &e) {
      cerr << e.what() << endl;
      exit(1);
    } 

  } else {
    // Node C

    try {
      string current_line;
      ifstream confCFile ("confC.txt");

      // Apparently this is the more C++ way to do atoi(current_line)?
      getline(confCFile, current_line); // First line; contains node B port
      unsigned short nodeCPort = string_to_us(current_line);

      TCPServerSocket servNodeC(nodeCPort);     // Server Socket object

      // Get connection from Node B
      HandleTCPClient(servNodeC.accept(), "C");   // Wait for a client to connect

    } catch(SocketException &e) {
      cerr << e.what() << endl;
      exit(1);
    } 

  }

  return 0;
}

// for nodes B and C
void HandleTCPClient(TCPSocket *sock, string nodeName) {
  char echoBuffer[RCVBUFSIZE] = {'\0'};
  int recvMsgSize;

  cout << "Node " << nodeName << " received: ";

  while ((recvMsgSize = sock->recv(echoBuffer, RCVBUFSIZE)) > 0) { // Zero means EOT
    echoBuffer[recvMsgSize] = '\0'; // Gotta clean up the trash from last iteration.
    cout << echoBuffer;
  }

  delete sock;
}


unsigned short string_to_us(string instring) {
  // Apparently this is a more C++ way to do atoi(current_line)?
  stringstream convert(instring);
  unsigned short outnum;
  convert >> outnum;
  return outnum;
}


void send_until_eof(TCPSocket *sock, ifstream *infile) {
  string current_line;
  if (infile->is_open()) {
    while (getline(*infile, current_line)) {
      // Send the string to the server
      stringstream line_with_end;
      line_with_end << current_line << endl;
      sock->send(line_with_end.str().c_str(), line_with_end.str().size());
    }
  }
}