Subversion Repositories programming

/*******************************************************************************
 * File: P3_ServerThread.java
 * Author: Ira W. Snyder (devel@irasnyder.com)
 * License: GNU General Public License v2
 * Class: CS380 - Computer Networking
 *
 * Assignment: Project #3
 * Date Last Modified: 2006-02-15
 *
 * Purpose: Implement a thread that takes an accepted TCP socket, and handles
 * all of the communication between the DHCP Server and the Client program.
 * It waits until the DHCP Server expires the lease to tell the client that
 * the lease has expired, and then exits.
 ******************************************************************************/

import java.net.*;
import java.io.*;

public class P3_ServerThread extends Thread
{
    /* Instance Variables */
    private Socket socket = null;
    private DHCPTable table = null;

    /**
     * Method: P3_ServerThread constructor
     * Purpose: Construct a new thread that will handle dealing with a
     * DHCP client.
     */
    public P3_ServerThread (Socket socket, DHCPTable table)
    {
        super ("P3_ServerThread");
        this.socket = socket;
        this.table = table;
    }

    /**
     * Method: run
     * Purpose: Communicate with the client
     */
    public void run ()
    {
        BufferedReader in = null;
        PrintWriter out = null;

        // Set up communication to the server
        try
        {
            out = new PrintWriter (socket.getOutputStream(), true);
            in = new BufferedReader (
                     new InputStreamReader (
                         socket.getInputStream()));
        }
        catch (IOException ex)
        {
            ex.printStackTrace();
        }

        String inputLine, outputLine;
        DHCPTableEntry e, expired;
        String[] splitInput = new String[1];

        // Try to get "req IP <HWAddr>" message
        try
        {
            inputLine = in.readLine();
            splitInput = inputLine.split(" ");
        }
        catch (IOException ex)
        {
            ex.printStackTrace();
        }

        // Make sure the request was ok
        if (splitInput.length != 3 &&
            !splitInput[0].equals("req") &&
            !splitInput[1].equals("IP"))
        {
            System.err.println ("REQ was not the first message!");
            out.println ("BAD REQUEST");
            return; // Leave uncleanly
        }

        // Get the next entry in the DHCPTable
        e = table.addEntry (splitInput[2]);

        // Print out DHCP Server info
        System.out.printf ("Client Added:   IP=%s -- HW=%s\n", e.getIPAddr(), e.getHWAddr());

        // Send out the client's IP Address
        out.println ("IPAddr: " + e.getIPAddr());

        // wait for timeout of this entry
        expired = table.timeoutEntry (e.getIPAddr());
        while (expired == null)
        {
            expired = table.timeoutEntry (e.getIPAddr());
        }

        // Print DHCP Server info
        System.out.printf ("Client Expired: IP=%s -- HW=%s\n",
                expired.getIPAddr(), expired.getHWAddr());

        // Tell the client that it expired
        out.println ("IP Lease Time Expired");

        // Try to cleanup sockets
        try
        {
            out.close();
            in.close();
            socket.close();
        }
        catch (IOException ex)
        {
            ex.printStackTrace();
        }
    }
}