/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
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/*
 * Copyright (c) 1999 by Sun Microsystems, Inc.
 * All rights reserved.
 *
 */

//  DAAdvertiser.java: Advertise a DA, also handle incoming DAAdverts.
//  Author:           James Kempf
//  Created On:       Tue May 19 15:22:04 1998
//  Last Modified By: James Kempf
//  Last Modified On: Thu Mar  4 10:39:06 1999
//  Update Count:     44
//

package com.sun.slp;

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

/**
 * This class supplies a regular interval 'heartbeat' DAAdvertisement.
 * Implementation specific subclasses handle incoming DAAdverts and
 * forwarding of registrations and deregistrations to other DAs. The
 * implementation specific subclasses depend on how the server is
 * representing DA information internally.
 *
 * @author James Kempf, Erik Guttman
 */

class DAAdvertiser extends Thread {

    protected DatagramSocket dss = null;
    protected InetAddress castAddr = null;
    protected InetAddress interfac = null;

    // V2 advertising has the same DAAdvert every time.

    static private byte[]        outbuf = null;

    static protected SLPConfig config = null;    // Config object.
    static protected Hashtable daadv =
        new Hashtable();        // Existing advertisers

    private Boolean done = Boolean.valueOf(false);

    // Initialize the DAAdvertiser on the designated interface.

    static void initializeDAAdvertiserOnInterface(InetAddress interfac)
        throws ServiceLocationException {

        // If we've got it, return.

        if (daadv.get(interfac) != null) {
            return;

        }

        // Get the config object.

        if (config == null) {
            config = SLPConfig.getSLPConfig();

        }

        // Get the SLPv2 DAADvert to send

        ServiceTable table = ServiceTable.getServiceTable();

        SLPServerHeaderV2 hdr =
            new SLPServerHeaderV2(SrvLocHeader.DAAdvert,
                                  false,
                                  config.getLocale());

        SDAAdvert msg =
            (SDAAdvert)table.makeDAAdvert(hdr,
                                          interfac,
                                          (short)0x0,
                                          config.getSAConfiguredScopes(),
                                          config);

        // Create a new DAAdvertiser for this interface, with SLPv2
        //  message to send.

        DAAdvertiser daadv = new DAAdvertiser(interfac, msg.getHeader());

        // Start thread running.

        daadv.start();

    }

    // Used by V1 subclass constructor.

    DAAdvertiser() {

        if (config == null) {
            config = SLPConfig.getSLPConfig();

        }

    }

    // Create a new DAAdvertiser for the interface for default multicast
    //  address. Externalize the message and set the instance variable.

    DAAdvertiser(InetAddress interfac, SrvLocHeader hdr)
        throws ServiceLocationException {

        // Config may not be initialized if this was called directly from
        //  slpd.

        if (config == null) {
            config = SLPConfig.getSLPConfig();

        }

        // Externalize the DAAdvert.

        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        hdr.externalize(baos, true, false);
        outbuf = baos.toByteArray();

        // Initialize the networking for default multicast address.

        initializeNetworking(interfac, config.getMulticastAddress());

    }


    // Convert advert to bytes, initialize networking.

    protected void
        initializeNetworking(InetAddress interfac,
                             InetAddress maddr)
        throws ServiceLocationException {

        // Set the interface and multicast address on this advertiser.

        this.interfac = interfac;
        this.castAddr = maddr;

        // Get the socket from the listener object corresponding to this
        //  interface. The listener will always be started before the
        //  DAAdvertiser, otherwise, SAs may start sending registrations
        //  before anybody is listening.

        dss = Listener.returnListenerSocketOnInterface(interfac);

        // If the socket is null, then there is no listener. Open a
        //  new socket. Note that any listener opened *afterwards* will
        //  not get this socket.

        if (dss == null) {
            dss = config.getMulticastSocketOnInterface(interfac, true);

        }
    }

    public void run() {

        // Set the thread name.

        setName("SLP DA Advertisement");

        long heartbeat = config.getAdvertHeartbeatTime() * 1000;

        while (true) {

            // Send an advert.

            sendAdvert();

            // Sleep until next time.

            try {
                sleep(heartbeat);

            } catch (InterruptedException ie) {

                // Somebody interrupted us. If we are to exit, then do so.

                synchronized (this) {

                    if (done.booleanValue()) {
                        return;

                    }
                }

            }

        }
    }

    // Send an unsolicited DAAdvert.

    void sendAdvert() {

        byte[] buf = getOutbuf();

        DatagramPacket dp =
            new DatagramPacket(buf,
                               buf.length,
                               castAddr,
                               Defaults.iSLPPort);
        try {

            dss.send(dp);

        } catch (IOException ex) {
            config.writeLog("passive_advert_exception",
                            new Object[] {ex.getMessage()});

            // Tell the listener to refresh the socket.

            dss = Listener.refreshSocketOnInterface(interfac);

        }
    }

    // Return the buffer for transmission.

    protected byte[] getOutbuf() {
        return outbuf;

    }

    // Stop the thread from executing.

    void stopThread() {

        synchronized (this) {
            done = Boolean.valueOf(true);

        }

        this.interrupt();

    }
}