client.java

来自「DSr project for the java applications」· Java 代码 · 共 117 行

package dsr;


//this is an client that basically initiates the DSR application.
//the logic followed here is, the client wants to send a data packet to some destination
//if there is route to the destination in the routing table, it sends the packet directly,
//otherwise it asks the DSR application to find a route to that destination

import java.net.*;
import java.io.*;
import java.util.*;
import java.lang.*;

public class Client {
  private static final int TIMEOUT = 3000;
  private static final int MAXTRIES = 5;

//initialises the various queues and tables.
  public static TimerQueue timerQueue = new TimerQueue();
  public static FloodIDQueue floodQueue = new FloodIDQueue();
  public static EventQueue eventQueue = new EventQueue();
  public static RouteTable routeTable = new RouteTable();
  //public static NeighborList neighborList;
  public static InterfaceList intQueue = new InterfaceList();


  public static void main (String[] args) throws IOException {
    if ((args.length < 1) || (args.length > 2))
      throw new IllegalArgumentException("Parameters: <Server> <word> [<port>]");

    //get the local address, uses the last adddress in the interface table as the local address
    InetAddress localAddress =
        ((InterfaceListEntry)InterfaceList.interfaceList.lastElement()).ipAddress;
    //gets the server address from the command line address.
    InetAddress serverAddress = InetAddress.getByName(args[0]);
    System.out.println("the serveraddress is " + serverAddress.getHostAddress().toString());
    System.out.println("the localaddress is " + localAddress.getHostAddress().toString());

    //Printing out the routing table
    RouteTable.PrintRouteTable();

    int echoServPort = 0;   //Echo server port
    if (args.length == 2)
      echoServPort = Integer.parseInt(args[1]);
    else
      System.out.println("Please enter a port where the packet is to be sent");

    //Create a UDP socket for sending and receiving.
    DatagramSocket socket = new DatagramSocket(echoServPort, localAddress);

    //set the maximum time to wait on a receive (milliseconds)
    socket.setSoTimeout(TIMEOUT);
    RREQPacket rreqPacket = new RREQPacket();
    InetAddress nextHopAddress = InetAddress.getByName("0.0.0.0");

    //RouteTableEntry tmpEntry = new RouteTableEntry();
    int i = RouteTable.FindRouteTableEntry(serverAddress);
    if (i == -1){
      //entry not found for that destination
      //generate an RREQ and do a local broadcast

      RREQ.genRREQ(localAddress, serverAddress);
      return;
    }
    else {
      //there is an entry in the routing table for that destination
      //so use that destination and send the packet
      //here the packet sent is a data packet.
      //for the time being let it be an RREQ packet with type as 3 and IP addresss 111.111.111.111
      InetAddress tempIP = InetAddress.getByName("111.111.111.111");
      rreqPacket = new RREQPacket((byte)3, (short)3, (byte)4, tempIP, 1000, tempIP, 1000);
      //nextHopAddress = tmpEntry.nextHop;
      nextHopAddress = (InetAddress)RouteTable.routingTable.elementAt(i);
    }

    //Convert the arguement string to bytes via the default encoding
    //System.out.println("first time : " + rreqPacket.toString());
    byte[] bytesToSend = RREQPacket.encode(rreqPacket);

    //Create a datagram to send
    DatagramPacket sendPacket = new DatagramPacket(bytesToSend, bytesToSend.length,
        nextHopAddress, echoServPort);

    System.out.println("data sent to add " + nextHopAddress.toString());
    //Create a datagram paket to recieve
    DatagramPacket recvPacket = new DatagramPacket(new byte[bytesToSend.length],
        bytesToSend.length);

    //packets may be lost so we need to keep trying
    int tries = 0;                      //number of tries to receive a packet
    boolean receivedResponse = false;   //true if packet was received
    do {
      socket.send(sendPacket);          //send the echo string
      try {
        socket.receive(recvPacket);     //Attempt to receive packet
        System.out.println("the packet is received from " + recvPacket.getAddress().toString());
        //if (!recvPacket.getAddress().equals(serverAddress))
          //throw new IOException("Received packet from an unknown source");

        receivedResponse = true;
      } catch (InterruptedIOException e) {
        tries += 1;
        System.out.println("Timed Out, " + (MAXTRIES - tries) + "more tries...");
      }
    } while ((!receivedResponse) && (tries < MAXTRIES));

    if (receivedResponse) {
      rreqPacket = rreqPacket.decode(recvPacket);
      System.out.println("the packet type is " + rreqPacket.type);
      System.out.println("\n the received packect is " + rreqPacket.toString());
    }
    else
      System.out.println("No response -- giving up");
    socket.close();
  }
}