/* $Id: UdpConnection.java 742162 2009-02-08 20:54:34Z dixson $
*
* Copyright 2007-2008 Cisco Systems Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy
* of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package etch.util.core.io;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;
import etch.util.FlexBuffer;
import etch.util.Resources;
import etch.util.URL;
import etch.util.core.Who;
/**
* Implementation of connection which handles a udp connection.
*/
public class UdpConnection extends Connection<SessionPacket>
implements TransportPacket
{
/**
* Term on the uri which specifies the default traffic class.
* @see #setDefaultTrafficClass(int)
*/
private static final String TRAFFIC_CLASS = "UdpConnection.trafficClass";
/**
* Constructs the Connection from a uri.
* @param uri
* @param resources
* @throws Exception
*/
public UdpConnection( String uri, Resources resources )
throws Exception
{
URL u = new URL( uri );
listen = u.getBooleanTerm( "listen", false );
host = translateHost( u.getHost() );
if (!listen && host == null)
throw new IllegalArgumentException( "host == null" );
port = u.getPort();
if (port == null)
throw new IllegalArgumentException( "port == null" );
if (port <= 0 || port > 65535)
throw new IllegalArgumentException( "port <= 0 || port > 65535" );
setDefaultTrafficClass( u.getIntegerTerm( TRAFFIC_CLASS, 0 ) );
// there are three ways to do this:
// 1. bound socket, unconnected (listening to anyone on well-known host/port
// 2. bound socket, connected (listening to someone on well-known host/port)
// 3. unbound socket, connected (listening to someone on assigned host/port)
}
private final String host;
private final Integer port;
private final boolean listen;
private DatagramSocket socket;
// TODO assign defaultRecipient a value somehow
private Who defaultRecipient;
/**
* Sets the default value for the traffic class (or type of service
* or dscp). For example, call signaling traffic is classified as
* DSCP CS3 (011000) with resulting traffic class value of 01100000,
* 0x60, or 96. For more on DSCP see RFC 2474 (supercedes TOS defined
* in RFC 791)
* @param trafficClass traffic class or type of service or dscp. The
* default is 0, which implies normal handling.
*/
public void setDefaultTrafficClass( int trafficClass )
{
this.trafficClass = trafficClass;
}
private int trafficClass = 0;
@Override
protected synchronized boolean openSocket( boolean reconnect ) throws Exception
{
if (socket != null)
socket.close();
socket = new DatagramSocket();
if (listen)
socket.bind( host != null ? new InetSocketAddress( host, port ) : new InetSocketAddress( port ) );
else
socket.connect( new InetSocketAddress( host, port ) );
if (!reconnect && socket != null)
return true;
return false;
}
@Override
protected void setupSocket() throws Exception
{
DatagramSocket s = checkSocket();
s.setTrafficClass( trafficClass );
}
@Override
protected void readSocket() throws Exception
{
final DatagramSocket s = checkSocket();
// TODO allow buffer size to be specified.
final FlexBuffer buf = new FlexBuffer( new byte[8192] );
final DatagramPacket p = new DatagramPacket( new byte[0], 0 );
try
{
while (isStarted())
{
p.setData( buf.getBuf() );
s.receive( p );
buf.setIndex( 0 );
buf.setLength( p.getLength() );
if (s.isConnected())
session.sessionPacket( null, buf );
else
session.sessionPacket( getWho( p.getAddress(), p.getPort() ), buf );
}
}
catch ( SocketException e )
{
if ("socket closed".equalsIgnoreCase( e.getMessage()))
return;
throw e;
}
}
private DatagramSocket checkSocket() throws IOException
{
DatagramSocket s = socket;
if (s == null || s.isClosed())
throw new SocketException( "socket closed" );
return s;
}
private Who getWho( InetAddress address, int port )
{
if (lastWho == null || !lastWho.matches( address, port ))
lastWho = new InetWho( address, port );
return lastWho;
}
private InetWho lastWho;
private final DatagramPacket outp = new DatagramPacket( new byte[0], 0 );
public void transportPacket( Who recipient, FlexBuffer buf ) throws IOException
{
// System.out.printf( "packet( %s, buf( %d, %d ))", recipient, buf.index(), buf.avail() );
if (socket.isConnected())
{
outp.setData( buf.getBuf(), buf.index(), buf.avail() );
socket.send( outp );
return;
}
if (recipient == null)
recipient = defaultRecipient;
if (recipient != null)
{
InetWho iw = (InetWho) recipient;
outp.setData( buf.getBuf(), buf.index(), buf.avail() );
outp.setAddress( iw.getInetAddress() );
outp.setPort( iw.getPort() );
socket.send( outp );
return;
}
throw new IllegalArgumentException( "no recipient" );
}
public int headerSize()
{
return 0;
}
@Override
public void close( boolean reset )
{
DatagramSocket s = socket;
if (s != null)
{
socket = null;
s.close();
}
}
@Override
public SocketAddress localAddress()
{
return socket.getLocalSocketAddress();
}
@Override
public SocketAddress remoteAddress()
{
return socket.getRemoteSocketAddress();
}
}