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/*******************************************************************************
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 * File: P3_ServerThread.java
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 * Author: Ira W. Snyder (devel@irasnyder.com)
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 * License: GNU General Public License v2
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 * Class: CS380 - Computer Networking
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 *
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 * Assignment: Project #3
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 * Date Last Modified: 2006-02-15
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 *
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 * Purpose: Implement a thread that takes an accepted TCP socket, and handles
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 * all of the communication between the DHCP Server and the Client program.
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 * It waits until the DHCP Server expires the lease to tell the client that
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 * the lease has expired, and then exits.
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 ******************************************************************************/
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import java.net.*;
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import java.io.*;
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public class P3_ServerThread extends Thread
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{
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    /* Instance Variables */
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    private Socket socket = null;
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    private DHCPTable table = null;
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    /**
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     * Method: P3_ServerThread constructor
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     * Purpose: Construct a new thread that will handle dealing with a
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     * DHCP client.
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     */
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    public P3_ServerThread (Socket socket, DHCPTable table)
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    {
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        super ("P3_ServerThread");
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        this.socket = socket;
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        this.table = table;
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    }
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    /**
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     * Method: run
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     * Purpose: Communicate with the client
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     */
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    public void run ()
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    {
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        BufferedReader in = null;
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        PrintWriter out = null;
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        // Set up communication to the server
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        try
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        {
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            out = new PrintWriter (socket.getOutputStream(), true);
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            in = new BufferedReader (
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                     new InputStreamReader (
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                         socket.getInputStream()));
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        }
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        catch (IOException ex)
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        {
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            ex.printStackTrace();
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        }
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        String inputLine, outputLine;
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        DHCPTableEntry e, expired;
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        String[] splitInput = new String[1];
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        // Try to get "req IP <HWAddr>" message
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        try
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        {
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            inputLine = in.readLine();
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            splitInput = inputLine.split(" ");
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        }
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        catch (IOException ex)
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        {
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            ex.printStackTrace();
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        }
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        // Make sure the request was ok
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        if (splitInput.length != 3 &&
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            !splitInput[0].equals("req") &&
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            !splitInput[1].equals("IP"))
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        {
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            System.err.println ("REQ was not the first message!");
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            out.println ("BAD REQUEST");
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            return; // Leave uncleanly
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        }
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        // Get the next entry in the DHCPTable
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        e = table.addEntry (splitInput[2]);
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        // Print out DHCP Server info
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        System.out.printf ("Client Added:   IP=%s -- HW=%s\n", e.getIPAddr(), e.getHWAddr());
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        // Send out the client's IP Address
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        out.println ("IPAddr: " + e.getIPAddr());
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        // wait for timeout of this entry
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        expired = table.timeoutEntry (e.getIPAddr());
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        while (expired == null)
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        {
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            expired = table.timeoutEntry (e.getIPAddr());
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        }
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        // Print DHCP Server info
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        System.out.printf ("Client Expired: IP=%s -- HW=%s\n",
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                expired.getIPAddr(), expired.getHWAddr());
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        // Tell the client that it expired
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        out.println ("IP Lease Time Expired");
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        // Try to cleanup sockets
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        try
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        {
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            out.close();
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            in.close();
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            socket.close();
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        }
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        catch (IOException ex)
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        {
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            ex.printStackTrace();
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        }
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    }
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}
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