receiver.java

来自「opennms得相关源码 请大家看看」· Java 代码 · 共 178 行

//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified 
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2003 Jan 31: Cleaned up some unused imports.
//
// Original code base Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.                                                            
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//       
// For more information contact: 
//      OpenNMS Licensing       <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Stop = 8
//

package org.opennms.netmgt.dhcpd;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.util.Iterator;
import java.util.List;

import org.apache.log4j.Category;
import org.opennms.core.fiber.Fiber;
import org.opennms.core.utils.ThreadCategory;

import edu.bucknell.net.JDHCP.DHCPMessage;

final class Receiver implements Runnable, Fiber {
    private final static short DHCP_TARGET_PORT = 68;

    private DatagramSocket m_receiver;

    private String m_name;

    private int m_status;

    private Thread m_worker;

    private List m_clients;

    Receiver(List clients) throws IOException {
        m_name = "DHCPReceiver";
        m_worker = null;
        m_status = START_PENDING;
        m_receiver = new DatagramSocket(DHCP_TARGET_PORT);
        m_receiver.setSoTimeout(1000);
        m_clients = clients;
    }

    public synchronized void start() {
        if (m_worker != null)
            throw new IllegalStateException("The fiber has already been started");

        m_worker = new Thread(this, getName());
        m_worker.setDaemon(true);
        m_worker.start();
        m_status = STARTING;
    }

    public synchronized void stop() {
        m_status = STOP_PENDING;
        m_receiver.close();
        m_worker.interrupt();
    }

    public synchronized int getStatus() {
        return m_status;
    }

    public String getName() {
        return m_name;
    }

    public void run() {
        Category log = ThreadCategory.getInstance(getClass());

        // set the state
        //
        synchronized (this) {
            m_status = RUNNING;
        }

        byte[] dgbuf = new byte[2048];

        // Roundy, Roundy, Round we go...
        //
        for (;;) {
            try {
                DatagramPacket pkt = new DatagramPacket(dgbuf, dgbuf.length);
                m_receiver.receive(pkt);
                log.debug("got a DHCP response.");
                Message msg = new Message(pkt.getAddress(), new DHCPMessage(pkt.getData()));

                synchronized (m_clients) {
                    Iterator iter = m_clients.iterator();
                    if(!iter.hasNext()) {
                        log.debug("No client waiting for response.");
                    }
                    while (iter.hasNext()) {
                        Client c = (Client) iter.next();
                        if (c.getStatus() == RUNNING) {
                            try {
                                log.debug("sending DHCP response pkt to client " + c.getName());
                                c.sendMessage(msg);
                            } catch (IOException ex) {
                                log.warn("Error sending response to client " + c.getName());
                            }
                        } else if (c.getStatus() == STOPPED) {
                            log.debug("Removing stale client " + c.getName());
                            iter.remove();
                        }
                    }
                }

            } catch (InterruptedIOException ex) {
                // ignore
            } catch (IOException ex) {
                synchronized (this) {
                    if (m_status == RUNNING)
                        log.warn("Failed to read message, I/O error", ex);
                }
                break;
            } catch (Throwable t) {
                synchronized (this) {
                    if (m_status == RUNNING)
                        log.warn("Undeclared throwable caught", t);
                }
                break;
            }

            synchronized (this) {
                if (m_status != RUNNING)
                    break;
            }
        }

        synchronized (this) {
            m_status = STOP_PENDING;
        }

        // close the datagram socket
        //
        m_receiver.close();

        synchronized (this) {
            m_status = STOPPED;
        }

    } // end run() method

}