/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.directory.server.dhcp.protocol;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import org.apache.directory.server.dhcp.messages.DhcpMessage;
import org.apache.directory.server.dhcp.messages.MessageType;
import org.apache.directory.server.dhcp.service.DhcpService;
import org.apache.mina.core.service.IoHandler;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Implementation of a DHCP protocol handler which delegates the work of
* generating replys to a DhcpService implementation.
*
* @see org.apache.directory.server.dhcp.service.DhcpService
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev: 725712 $, $Date: 2008-12-11 16:32:04 +0100 (Jeu, 11 déc 2008) $
*/
public class DhcpProtocolHandler implements IoHandler {
private static final Logger logger = LoggerFactory
.getLogger(DhcpProtocolHandler.class);
/**
* Default DHCP client port
*/
public static final int CLIENT_PORT = 68;
/**
* Default DHCP server port
*/
public static final int SERVER_PORT = 67;
/**
* The DHCP service implementation. The implementation is supposed to be
* thread-safe.
*/
private final DhcpService dhcpService;
/**
*
*/
public DhcpProtocolHandler(DhcpService service) {
this.dhcpService = service;
}
public void sessionCreated(IoSession session) throws Exception {
logger.debug("{} CREATED", session.getLocalAddress());
session.getFilterChain().addFirst("codec",
new ProtocolCodecFilter(new DhcpProtocolCodecFactory()));
}
public void sessionOpened(IoSession session) {
logger.debug("{} -> {} OPENED", session.getRemoteAddress(), session
.getLocalAddress());
}
public void sessionClosed(IoSession session) {
logger.debug("{} -> {} CLOSED", session.getRemoteAddress(), session
.getLocalAddress());
}
public void sessionIdle(IoSession session, IdleStatus status) {
// ignore
}
public void exceptionCaught(IoSession session, Throwable cause) {
logger.error("EXCEPTION CAUGHT ", cause);
cause.printStackTrace(System.out);
session.close( true );
}
public void messageReceived(IoSession session, Object message)
throws Exception {
if (logger.isDebugEnabled())
logger.debug("{} -> {} RCVD: {} " + message, session.getRemoteAddress(),
session.getLocalAddress());
final DhcpMessage request = (DhcpMessage) message;
final DhcpMessage reply = dhcpService.getReplyFor(
(InetSocketAddress) session.getServiceAddress(),
(InetSocketAddress) session.getRemoteAddress(), request);
if (null != reply) {
final InetSocketAddress isa = determineMessageDestination(request, reply);
session.write(reply, isa);
}
}
/**
* Determine where to send the message: <br>
* If the 'giaddr' field in a DHCP message from a client is non-zero, the
* server sends any return messages to the 'DHCP server' port on the BOOTP
* relay agent whose address appears in 'giaddr'. If the 'giaddr' field is
* zero and the 'ciaddr' field is nonzero, then the server unicasts DHCPOFFER
* and DHCPACK messages to the address in 'ciaddr'. If 'giaddr' is zero and
* 'ciaddr' is zero, and the broadcast bit is set, then the server broadcasts
* DHCPOFFER and DHCPACK messages to 0xffffffff. If the broadcast bit is not
* set and 'giaddr' is zero and 'ciaddr' is zero, then the server unicasts
* DHCPOFFER and DHCPACK messages to the client's hardware address and
* 'yiaddr' address. In all cases, when 'giaddr' is zero, the server
* broadcasts any DHCPNAK messages to 0xffffffff.
*
* @param request
* @param reply
* @return
*/
private InetSocketAddress determineMessageDestination(DhcpMessage request,
DhcpMessage reply) {
final MessageType mt = reply.getMessageType();
if (!isNullAddress(request.getRelayAgentAddress()))
// send to agent, if received via agent.
return new InetSocketAddress(request.getRelayAgentAddress(), SERVER_PORT);
else if (null != mt && mt == MessageType.DHCPNAK)
// force broadcast for DHCPNAKs
return new InetSocketAddress("255.255.255.255", 68);
else // not a NAK...
if (!isNullAddress(request.getCurrentClientAddress()))
// have a current address? unicast to it.
return new InetSocketAddress(request.getCurrentClientAddress(),
CLIENT_PORT);
else
return new InetSocketAddress("255.255.255.255", 68);
}
/**
* Determine, whether the given address ist actually the null address
* "0.0.0.0".
*
* @param relayAgentAddress
* @return
*/
private boolean isNullAddress(InetAddress addr) {
final byte a[] = addr.getAddress();
for (int i = 0; i < a.length; i++)
if (a[i] != 0)
return false;
return true;
}
public void messageSent(IoSession session, Object message) {
if (logger.isDebugEnabled())
logger.debug("{} -> {} SENT: " + message, session.getRemoteAddress(),
session.getLocalAddress());
}
}