routeresolver.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

                
                // check if the bad hop is not the destination
                // if it is then we still have a bad route
                if (!(badHop.equals(router.addr2pid(addr)))) {
                    // check if the new route may still contain the bad hop
                    // the known bad hop is the hop after the src peer that
                    // responded with a NACK route
                    // In this case we also consider the route bad
                    if (badHop != null) { // this should really not be null
                        if (!currentRoute.containsHop(badHop)) {
                            return; // we are ok
                        } else {
                            if (LOG.isEnabledFor(Level.DEBUG)) {
                                LOG.debug("current route is bad because it contains known bad hop" + badHop);
                            }
                        }
                    } else { // we could get the bad hop, so consider the route ok
                        return;
                    }
                } else {
                    if (LOG.isEnabledFor(Level.DEBUG)) {
                        LOG.debug("current route is bad because it contains known bad destination" + badHop);
                    }
                }
                
            }
            
            // keep the bad one in a cache table so we don't retry them
            // right away. We use the default route timeout
            BadRoute badRoute = ((BadRoute) router.getBadRoute(addr));

            if (badRoute != null) {
                
                Long nextTry = badRoute.getExpiration();

                if (nextTry.longValue() > System.currentTimeMillis()) {// nothing to do the information is still valid
                } else {
                    // It is ancient knowlege update it
                    nextTry = new Long(TimeUtils.toAbsoluteTimeMillis(BADROUTE_EXPIRATION));
                    badRoute.setExpiration(nextTry);
                }
                
                List badHops = badRoute.getHops();

                // check if we have to add a new bad hop
                // to our bad route
                if (badHop != null) {
                    if (!badHops.contains(badHop)) {
                        badHops.add(badHop);
                        // new expiration
                        nextTry = new Long(TimeUtils.toAbsoluteTimeMillis(BADROUTE_EXPIRATION));
                        badRoute.setHops(badHops);
                        badRoute.setExpiration(nextTry);
                    }
                }
                
                router.setBadRoute(addr, badRoute);
                return;
            } else {
                // create a new NACK route entry
                Vector badHops = new Vector();

                if (badHop != null) {
                    badHops.add(badHop);
                }
                
                badRoute = new BadRoute(dest, new Long(TimeUtils.toAbsoluteTimeMillis(BADROUTE_EXPIRATION)), badHops);
                router.setBadRoute(addr, badRoute);
            }
            
            // remove route from route CM
            routeCM.flushRoute(addr);
            
            // let's remove the remote route info from the routing table
            // we do this after we removed the entries from the CM
            // to avoid that another thread is putting back the entry
            router.removeRoute(addr);
            
        } catch (Exception ex) {
            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn("exception during bad route removal", ex);
            }
        }
    }
    
    /**
     * Process the Query, and generate response
     * @param query the query to process
     */
    public int processQuery(ResolverQueryMsg query) {
        
        if (!useRouteResolver) { // Route resolver disabled
            return ResolverService.OK;
        }
        
        if (LOG.isEnabledFor(Level.DEBUG)) {
            LOG.debug("processQuery starts");
        }
        
        RouteQuery routeQuery = null;
        Reader ip = null;

        try {
            ip = new StringReader(query.getQuery());
            
            StructuredTextDocument asDoc = (StructuredTextDocument)
                    StructuredDocumentFactory.newStructuredDocument(MimeMediaType.XMLUTF8, ip);
            
            routeQuery = new RouteQuery(asDoc);
            
        } catch (Throwable e) {
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("Malformed Route query ", e);
            }
            return ResolverService.OK;
        } finally {
            try {
                if (null != ip) {
                    ip.close();
                    ip = null;
                }
            } catch (Throwable ignored) {
                ;
            }
        }
        
        PeerID pId = routeQuery.getDestPeerID();
        
        if (LOG.isEnabledFor(Level.DEBUG)) {
            LOG.debug("processQuery: looking for route to " + pId);
        }
        
        RouteAdvertisement srcRoute = routeQuery.getSrcRoute();
        List badHops = routeQuery.getBadHops();

        if (LOG.isEnabledFor(Level.DEBUG)) {
            if (badHops != null) {
                LOG.debug("processQuery: bad Hops");
                for (int i = 0; i < badHops.size(); i++) {
                    LOG.debug("processQuery:   :" + ((PeerID) badHops.get(i)).toString());
                }
            }
        }
        // if our source route is not null, then publish it
        if (srcRoute != null) {
            if (!(srcRoute.getDestPeerID()).equals(localPeerId)) {
                // This is not our own peer adv so we must not keep it
                // longer than its expiration time.
                try {
                    if (LOG.isEnabledFor(Level.DEBUG)) {
                        LOG.debug("processQuery: publishing sender route info " + srcRoute.getDestPeerID());
                    }
                    
                    // we only need to publish this route if
                    // we don't know about it yet
                    // XXX: here is where we could be more conservative and use isNormallyReachable() instead, thus excluding
                    // incoming messengers.
                    if ((!router.isLocalRoute(router.pid2addr(srcRoute.getDestPeerID())))
                            && (!router.isRoutedRoute(router.pid2addr(srcRoute.getDestPeerID())))) {
                        routeCM.publishRoute(srcRoute);
                    }
                } catch (Exception e) {
                    if (LOG.isEnabledFor(Level.DEBUG)) {
                        LOG.debug("Could not publish Route Adv from query - discard", e);
                    }
                    return ResolverService.OK;
                }
            }
        } else {
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("No src Route in route query - discard ");
            }
            return ResolverService.OK;
        }
        
        if (pId == null) {
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("Malformed route query request, no PeerId - discard");
            }
            return ResolverService.OK;
        }
        
        // We have more luck with that one because, since it is part of OUR
        // message, and not part of the resolver protocol, it is in OUR
        // format.
        EndpointAddress qReqAddr = router.pid2addr(pId);
        
        RouteAdvertisement route = null;
        
        // check if this peer has a route to the destination
        // requested
        boolean found = false;

        if (qReqAddr.equals(localPeerAddr)) {
            found = true;
            // return the route that is my local route
            route = router.getMyLocalRoute();
        } else {
            // only rendezvous can respond to route requests
            // if not we are generating too much traffic
            // XXX: here is where we could be more conservative and use isNormallyReachable() instead, thus excluding
            // incoming messengers.
            if (router.isLocalRoute(qReqAddr)) {
                if (LOG.isEnabledFor(Level.DEBUG)) {
                    LOG.debug("processQuery: peer has direct route to destination ");
                }
                // we should set the route to something  :-)
                
                found = true;
                
                // this peer has a direct route to the destination
                // return the short route advertisement we know for this peer
                // (For us it is zero hop, and we advertise ourself as the routing
                // peer in the response. The stiching is done by whoever gets that
                // response). May be there are more than one hop advertised in-there...
                // alternate routing peers...should we leave them ?
                // For now, we keep the full dest, but wack the hops.
                
                route = (RouteAdvertisement)
                        AdvertisementFactory.newAdvertisement(RouteAdvertisement.getAdvertisementType());
                
                AccessPointAdvertisement ap = (AccessPointAdvertisement)
                        AdvertisementFactory.newAdvertisement(AccessPointAdvertisement.getAdvertisementType());

                ap.setPeerID(pId);
                route.setDest(ap);
                
            } else {
                
                route = router.getRoute(qReqAddr, false);
                if (route != null) {
                    found = true;
                    // check if we were given some bad hops info
                    // and see if the found route contains
                    // any of these bad hops. In that case, we need
                    // to mark this route as bad
                    for (int i = 0; i < badHops.size(); i++) {
                        
                        // destination is known to be bad
                        if (router.addr2pid(qReqAddr).equals(((PeerID) badHops.get(i)))) {
                            processBadRoute((PeerID) badHops.get(i), route);
                            found = false;
                            break;
                        }
                        
                        if (route.containsHop((PeerID) badHops.get(i))) {
                            if (LOG.isEnabledFor(Level.DEBUG)) {
                                LOG.debug("processQuery: peer has bad route due to " + ((PeerID) badHops.get(i)).toString());
                            }
                            processBadRoute((PeerID) badHops.get(i), route);
                            found = false;
                            break;
                        }
                    }
                }
            }
        }
        
        if (!found) {
            // discard the request if we are not a rendezvous
            // else forward to the next peers
            if (!group.isRendezvous()) {
                if (LOG.isEnabledFor(Level.DEBUG)) {
                    LOG.debug("discard query forwarding as not a rendezvous");
                }
                return ResolverService.OK;
            }
            
            // did not find a route, check our srdi cache
            // make sure we protect against out of sync
            // SRDI index
            
            // srdi forwarding is only involved once the Index entry has
            // been found and we forwarded the resolver query. Afterward a
            // normal walk proceeds from the initial SRDI index pointing
            // rdv. This is done to protect against potential loopback
            // entries in the SRDI cache index due to out of sync peerview
            // and index.
            if (query.getHopCount() < 2) {
                
                // check local SRDI cache to see if we have the entry
                // we look for 10 entries, will pickup one randomly
                Vector results = srdiIndex.query("route", "DstPID", pId.toString(), 10);

                if (results.size() > 0) {
                    if (LOG.isEnabledFor(Level.DEBUG)) {
                        LOG.debug("processQuery srdiIndex lookup match :" + results.size());
                    }
                    
                    // remove any non-rdv peers to avoid sending
                    // to a non-rdv peers and garbage collect the SRDI
                    // index in the process
                    Vector clean = cleanupAnyEdges(query.getSrc(), results);

                    if (clean.size() > 0) {
                        
                        if (LOG.isEnabledFor(Level.DEBUG)) {
                            LOG.debug("found an srdi entry forwarding query to SRDI peer");
                        }
                        
                        // The purpose of incrementing the hopcount
                        // when an SRDI index match is found (we got a
                        // pointer to a rdv that should have the route) is to
                        // restrict any further forwarding. The increment
                        // count is only done when a matching SRDI index is
                        // found. Not when the replica is selected as we
                        // still need to forward the query.  This restriction
                        // is purposelly done to avoid too many longjumps
                        // within a walk.
                        query.incrementHopCount();
                        
                        // Note: this forwards the query to 1 peer randomly
                        // selected from the result
                        srdi.forwardQuery(clean, query, 1);
                        
                        // tell the resolver no further action is needed.
                        return ResolverService.OK;
                    }
                }
            }
            
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("did not find a route or SRDI index");
            }
            
            // force a walk
            return ResolverService.Repropagate;
        }
        
        // we found a route send the response
        try {
            if (route == null) {
                if (LOG.isEnabledFor(Level.DEBUG)) {
                    LOG.debug("we should have had a route at this point");
                }
                return ResolverService.OK;
            }
            
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("processQuery: we have a route build route response" + route.display());
            }
            
            RouteAdvertisement myRoute = router.getMyLocalRoute();
	    
            // make sure we initialized our local
            // route info as we will need it to respond. We may
            // not have our route if we are still
            // waiting for a relay connection.
            if (myRoute == null) {
                return ResolverService.OK;
            }
	    
            RouteResponse routeResponse = new RouteResponse();
            
            routeResponse.setDestRoute(route);
            routeResponse.setSrcRoute(myRoute);
            
            if (routeResponse == null) {
                if (LOG.isEnabledFor(Level.DEBUG)) {
                    LOG.debug("error creating route response");
                }
                return ResolverService.OK;
            }