/****************************************************************
* This work is derived from 'jnamed.java' distributed in *
* 'dnsjava-2.0.5'. This original is licensed as follows: *
* Copyright (c) 1999-2005, Brian Wellington *
* All rights reserved. *
* *
* Redistribution and use in source and binary forms, with or *
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* materials provided with the distribution. *
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* of its contributors may be used to endorse or promote *
* products derived from this software without specific *
* prior written permission. *
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****************************************************************/
package org.apache.james.jspf.dnsserver;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public final class UDPListener implements Runnable {
private final static class UDPResponder implements Runnable {
private ResponseGenerator responseGenerator;
private DatagramSocket sock;
private InetAddress addr;
private int port;
private byte[] in;
private UDPResponder(DatagramSocket sock, InetAddress addr, int port, byte[] in, ResponseGenerator rg) {
this.sock = sock;
this.addr = addr;
this.port = port;
this.in = in;
this.responseGenerator = rg;
}
public void run() {
try {
DatagramPacket outdp = null;
byte[] response = responseGenerator.generateReply(in, in.length);
if (response == null)
return;
if (outdp == null) {
outdp = new DatagramPacket(response, response.length,
addr, port);
} else {
outdp.setData(response);
outdp.setLength(response.length);
outdp.setAddress(addr);
outdp.setPort(port);
}
sock.send(outdp);
} catch (IOException e) {
System.out.println("UDPResponder(" + addr.getHostAddress() + "#" + port + "): "
+ e);
}
}
}
private final InetAddress addr;
private final int port;
private ResponseGenerator responseGenerator;
UDPListener(InetAddress addr, int port, ResponseGenerator rg) {
this.addr = addr;
this.port = port;
this.responseGenerator = rg;
}
public void run() {
try {
DatagramSocket sock = new DatagramSocket(port, addr);
final short udpLength = 512;
byte[] in = new byte[udpLength];
DatagramPacket indp = new DatagramPacket(in, in.length);
while (true) {
indp.setLength(in.length);
try {
sock.receive(indp);
} catch (InterruptedIOException e) {
continue;
}
byte[] local = new byte[indp.getLength()];
System.arraycopy(in, 0, local, 0, indp.getLength());
Runnable runnable = new UDPResponder(sock, indp.getAddress(), indp.getPort(), local, responseGenerator);
new Thread(runnable).start();
}
} catch (IOException e) {
System.out.println("UDPListener(" + addr.getHostAddress() + "#" + port + "): "
+ e);
}
}
}