endpointrouter.java

JXTA&#8482 is a set of open, generalized peer-to-peer (P2P) protocols that allow any networked devi

/*
 * Copyright (c) 2001-2007 Sun Microsystems, Inc.  All rights reserved.
 *  
 *  The Sun Project JXTA(TM) Software License
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 *  Redistribution and use in source and binary forms, with or without 
 *  modification, are permitted provided that the following conditions are met:
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 *  1. Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
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 *     include the following acknowledgment: "This product includes software 
 *     developed by Sun Microsystems, Inc. for JXTA(TM) technology." 
 *     Alternately, this acknowledgment may appear in the software itself, if 
 *     and wherever such third-party acknowledgments normally appear.
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 *  Please see the license information page at :
 *  <http://www.jxta.org/project/www/license.html> for instructions on use of 
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 *  ====================================================================
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 *  This software consists of voluntary contributions made by many individuals 
 *  on behalf of Project JXTA. For more information on Project JXTA, please see 
 *  http://www.jxta.org.
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 *  This license is based on the BSD license adopted by the Apache Foundation. 
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package net.jxta.impl.endpoint.router;

import net.jxta.document.Advertisement;
import net.jxta.document.AdvertisementFactory;
import net.jxta.document.XMLElement;
import net.jxta.endpoint.EndpointAddress;
import net.jxta.endpoint.EndpointListener;
import net.jxta.endpoint.EndpointService;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.MessageReceiver;
import net.jxta.endpoint.MessageSender;
import net.jxta.endpoint.MessageTransport;
import net.jxta.endpoint.Messenger;
import net.jxta.endpoint.MessengerEvent;
import net.jxta.endpoint.MessengerEventListener;
import net.jxta.exception.PeerGroupException;
import net.jxta.id.ID;
import net.jxta.id.IDFactory;
import net.jxta.impl.endpoint.LoopbackMessenger;
import net.jxta.impl.util.TimeUtils;
import net.jxta.impl.util.TimerThreadNamer;
import net.jxta.logging.Logging;
import net.jxta.peer.PeerID;
import net.jxta.peergroup.PeerGroup;
import net.jxta.platform.Module;
import net.jxta.protocol.AccessPointAdvertisement;
import net.jxta.protocol.ModuleImplAdvertisement;
import net.jxta.protocol.PeerAdvertisement;
import net.jxta.protocol.RouteAdvertisement;
import net.jxta.service.Service;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;
import java.util.logging.Level;
import java.util.logging.Logger;

public class EndpointRouter implements EndpointListener, MessageReceiver, MessageSender, MessengerEventListener, Module {

    /**
     * Logger
     */
    private final static transient Logger LOG = Logger.getLogger(EndpointRouter.class.getName());

    /**
     * Until we decide otherwise, the router is *by definition* handling
     * virtually addressed messages.
     */
    private final static String ROUTER_PROTOCOL_NAME = "jxta";

    /**
     * Router Service Name
     */
    private final static String ROUTER_SERVICE_NAME = "EndpointRouter";

    /**
     * how long we are willing to wait for a response from an async
     * getMessenger. We do not wait long at all because it is non-critical
     * that we get the answer synchronously. The goal is to avoid starting
     * a route discovery if there's a chance to get a direct connection.
     * However, we will still take advantage of the direct route if it is
     * found while we wait for the route discovery result. If that happens,
     * the only wrong is that we used some bandwidth doing a route discovery
     * that wasn't needed after all.
     */
    public final static long ASYNC_MESSENGER_WAIT = 3L * TimeUtils.ASECOND;

    /**
     * MessageTransport Control operation
     */
    public final static Integer GET_ROUTE_CONTROL = 0; // Return RouteControl Object
    public final static int RouteControlOp = 0; // Return RouteControl Object

    /**
     * MAX timeout (seconds) for route discovery after that timeout
     * the peer will bail out from finding a route
     */
    private final static long MAX_FINDROUTE_TIMEOUT = 60L * TimeUtils.ASECOND;

    /**
     * How long do we wait (seconds) before retrying to make a connection
     * to an endpoint destination
     */
    private final static long MAX_ASYNC_GETMESSENGER_RETRY = 30L * TimeUtils.ASECOND;

    /**
     * These are peers which we know multi-hop routes for.
     */
    private final Map<ID, RouteAdvertisement> routedRoutes = new HashMap<ID, RouteAdvertisement>(16);

    /**
     * A record of failures.
     * <p/>
     * Values are the time of failure as {@link java.lang.Long}. If
     * {@code Long.MAX_VALUE} then a connect attempt is current in progress.
     */
    private final Map<PeerID, Long> triedAndFailed = new HashMap<PeerID, Long>();

    /**
     * local peer ID as an endpointAddress.
     */
    private EndpointAddress localPeerAddr = null;

    /**
     * local Peer ID
     */
    private PeerID localPeerId = null;

    /**
     * The Endpoint Service we are routing for.
     */
    private EndpointService endpoint = null;

    /**
     * PeerGroup handle
     */
    private PeerGroup group = null;

    private ID assignedID = null;
    
    /**
     * If {@code true} this service has been closed.
     */
    private boolean stopped = false;

    /**
     * Whenever we initiate connectivity to a peer (creating a direct route).
     * we remember that we need to send our route adv to that peer. So that
     * it has a chance to re-establish the connection from its side, if need
     * be. The route adv is actually sent piggy-backed on the first message
     * that goes there.
     */
    private final Set<EndpointAddress> newDestinations = Collections.synchronizedSet(new HashSet<EndpointAddress>());

    /**
     * A pool of messengers categorized by logical address.
     * This actually is the direct routes map.
     */
    private Destinations destinations;

    /**
     * A record of expiration time of known bad routes we received a NACK route
     */
    private final Map<EndpointAddress, BadRoute> badRoutes = new HashMap<EndpointAddress, BadRoute>();

    /**
     * We record queries when first started and keep them pending for
     * a while. Threads coming in the meanwhile wait for a result without
     * initiating a query. Thus threads may wait passed the point where
     * the query is no-longer pending, and, although they could initiate
     * a new one, they do not.
     * <p/>
     * However, other threads coming later may initiate a new query. So a
     * query is not re-initiated systematically on a fixed schedule. This
     * mechanism also serves to avoid infinite recursions if we're looking
     * for the route to a rendezvous (route queries will try to go there
     * themselves).
     * <p/>
     * FIXME: [e-mail] 20020903 this is approximate. We can do
     * cleaner/better than this, but it's already an inexpensive improvement
     * over what used before.
     * <p/>
     * FIXME: [e-mail] 20030818 the pending hashmap should be moved
     * in the routeResolver class.
     */
    private final Map<PeerID, ClearPendingQuery> pendingQueries = 
            Collections.synchronizedMap(new HashMap<PeerID, ClearPendingQuery>());

    /**
     * Timer by which we schedule the clearing of pending queries.
     */
    private final Timer timer = new Timer("EndpointRouter Timer", true);

    /**
     * PeerAdv tracking.
     * The peer adv is modified every time a new public address is
     * enabled/disabled. One of such cases is the connection/disconnection
     * from a relay. Since these changes are to the embedded route adv
     * and since we may embed our route adv in messages, we must keep it
     * up-to-date.
     */
    private PeerAdvertisement lastPeerAdv = null;
    private int lastModCount = -1;

    /**
     * Route info for the local peer (updated along with lastPeerAdv).
     */
    private RouteAdvertisement localRoute = null;

    /**
     * Route CM persistent cache
     */
    private RouteCM routeCM = null;

    /**
     * Route Resolver
     */
    private RouteResolver routeResolver;

    class ClearPendingQuery extends TimerTask {
        final PeerID peerID;
        volatile boolean failed = false;
        long nextRouteResolveAt = 0;

        ClearPendingQuery(PeerID peerID) {
            this.peerID = peerID;
            // We schedule for one tick at one minute and another at 5 minutes
            // after the second, we cancel ourselves.
            timer.schedule(this, TimeUtils.AMINUTE, 5L * TimeUtils.AMINUTE);
            nextRouteResolveAt = TimeUtils.toAbsoluteTimeMillis(20L * TimeUtils.ASECOND);
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public void run() {
            try {
                if (failed) {
                    // Second tick.
                    // This negative cache info is expired.
                    pendingQueries.remove(peerID);

                    this.cancel();
                } else {
                    // First timer tick. We're done trying. This is now a negative
                    // cache info. For the next 5 minutes that destination fails
                    // immediately unless it unexpectedly gets finaly resolved.
                    failed = true;
                }
            } catch (Throwable all) {
                if (Logging.SHOW_SEVERE && LOG.isLoggable(Level.SEVERE)) {
                    LOG.log(Level.SEVERE, "Uncaught Throwable in timer task " + Thread.currentThread().getName() + " for " + peerID, all);
                }
            }
        }

        public synchronized boolean isTimeToResolveRoute() {
            if (TimeUtils.toRelativeTimeMillis(nextRouteResolveAt) > 0) {
                return false;
            }
            // nextRouteResolveAt is passed. Set the next time to retry from now.
            nextRouteResolveAt = TimeUtils.toAbsoluteTimeMillis(20L * TimeUtils.ASECOND);
            return true;
        }

        public boolean isFailed() {
            return failed;
        }
    }

    RouteAdvertisement getMyLocalRoute() {

        // Update our idea of the local peer adv. If it has change,
        // update our idea of the local route adv.
        // If nothing has changed, do not do any work.
        // In either case, return the local route adv as it is after this
        // refresh.

        // Race condition possible but tolerable: if two threads discover
        // the change in the same time, lastPeerAdv and lastModCount
        // could become inconsistent. That'll be straightened out the
        // next time someone looks. The inconsistency can only trigger
        // an extraneous update.