Examples with RouterInfo net.i2p.data.router.RouterInfo used on opensource projects

Example 11 with RouterInfo

use of net.i2p.data.router.RouterInfo in project i2p.i2p by i2p.

the class EstablishmentManager method handleCompletelyEstablished.

/**
 * ok, fully received, add it to the established cons and queue up a
 * netDb store to them
 */
private void handleCompletelyEstablished(InboundEstablishState state) {
    if (state.isComplete())
        return;
    RouterIdentity remote = state.getConfirmedIdentity();
    PeerState peer = new PeerState(_context, _transport, state.getSentIP(), state.getSentPort(), remote.calculateHash(), true);
    peer.setCurrentCipherKey(state.getCipherKey());
    peer.setCurrentMACKey(state.getMACKey());
    peer.setWeRelayToThemAs(state.getSentRelayTag());
    // Lookup the peer's MTU from the netdb, since it isn't included in the protocol setup (yet)
    // TODO if we don't have RI then we will get it shortly, but too late.
    // Perhaps netdb should notify transport when it gets a new RI...
    RouterInfo info = _context.netDb().lookupRouterInfoLocally(remote.calculateHash());
    if (info != null) {
        RouterAddress addr = _transport.getTargetAddress(info);
        if (addr != null) {
            String smtu = addr.getOption(UDPAddress.PROP_MTU);
            if (smtu != null) {
                try {
                    boolean isIPv6 = state.getSentIP().length == 16;
                    int mtu = MTU.rectify(isIPv6, Integer.parseInt(smtu));
                    peer.setHisMTU(mtu);
                } catch (NumberFormatException nfe) {
                }
            }
        }
    }
    if (_log.shouldLog(Log.DEBUG))
        _log.debug("Handle completely established (inbound): " + state + " - " + peer.getRemotePeer());
    // if (true) // for now, only support direct
    // peer.setRemoteRequiresIntroduction(false);
    _transport.addRemotePeerState(peer);
    boolean isIPv6 = state.getSentIP().length == 16;
    _transport.inboundConnectionReceived(isIPv6);
    _transport.setIP(remote.calculateHash(), state.getSentIP());
    _context.statManager().addRateData("udp.inboundEstablishTime", state.getLifetime());
    sendInboundComplete(peer);
    OutNetMessage msg;
    while ((msg = state.getNextQueuedMessage()) != null) {
        if (_context.clock().now() - Router.CLOCK_FUDGE_FACTOR > msg.getExpiration()) {
            msg.timestamp("took too long but established...");
            _transport.failed(msg, "Took too long to establish, but it was established");
        } else {
            msg.timestamp("session fully established and sent");
            _transport.send(msg);
        }
    }
    state.complete();
}

Example 12 with RouterInfo

use of net.i2p.data.router.RouterInfo in project i2p.i2p by i2p.

the class EstablishmentManager method establish.

/**
 *  @param queueIfMaxExceeded true normally, false if called from locked_admit so we don't loop
 *  @since 0.9.2
 */
private void establish(OutNetMessage msg, boolean queueIfMaxExceeded) {
    RouterInfo toRouterInfo = msg.getTarget();
    RouterAddress ra = _transport.getTargetAddress(toRouterInfo);
    if (ra == null) {
        _transport.failed(msg, "Remote peer has no address, cannot establish");
        return;
    }
    RouterIdentity toIdentity = toRouterInfo.getIdentity();
    Hash toHash = toIdentity.calculateHash();
    if (toRouterInfo.getNetworkId() != _networkID) {
        _context.banlist().banlistRouter(toHash);
        _transport.markUnreachable(toHash);
        _transport.failed(msg, "Remote peer is on the wrong network, cannot establish");
        return;
    }
    UDPAddress addr = new UDPAddress(ra);
    RemoteHostId maybeTo = null;
    InetAddress remAddr = addr.getHostAddress();
    int port = addr.getPort();
    // claimed address (which we won't be using if indirect)
    if (remAddr != null && port > 0 && port <= 65535) {
        maybeTo = new RemoteHostId(remAddr.getAddress(), port);
        if ((!_transport.isValid(maybeTo.getIP())) || (Arrays.equals(maybeTo.getIP(), _transport.getExternalIP()) && !_transport.allowLocal())) {
            _transport.failed(msg, "Remote peer's IP isn't valid");
            _transport.markUnreachable(toHash);
            // _context.banlist().banlistRouter(msg.getTarget().getIdentity().calculateHash(), "Invalid SSU address", UDPTransport.STYLE);
            _context.statManager().addRateData("udp.establishBadIP", 1);
            return;
        }
        InboundEstablishState inState = _inboundStates.get(maybeTo);
        if (inState != null) {
            // we have an inbound establishment in progress, queue it there instead
            synchronized (inState) {
                switch(inState.getState()) {
                    case IB_STATE_UNKNOWN:
                    case IB_STATE_REQUEST_RECEIVED:
                    case IB_STATE_CREATED_SENT:
                    case IB_STATE_CONFIRMED_PARTIALLY:
                    case IB_STATE_CONFIRMED_COMPLETELY:
                        // queue it
                        inState.addMessage(msg);
                        if (_log.shouldLog(Log.WARN))
                            _log.debug("OB msg queued to IES");
                        break;
                    case IB_STATE_COMPLETE:
                        // race, send it out (but don't call _transport.send() again and risk a loop)
                        _transport.sendIfEstablished(msg);
                        break;
                    case IB_STATE_FAILED:
                        // race, failed
                        _transport.failed(msg, "OB msg failed during IB establish");
                        break;
                }
            }
            return;
        }
    }
    RemoteHostId to;
    boolean isIndirect = addr.getIntroducerCount() > 0 || maybeTo == null;
    if (isIndirect) {
        to = new RemoteHostId(toHash);
    } else {
        to = maybeTo;
    }
    OutboundEstablishState state = null;
    int deferred = 0;
    boolean rejected = false;
    int queueCount = 0;
    state = _outboundStates.get(to);
    if (state == null) {
        state = _outboundByHash.get(toHash);
        if (state != null && _log.shouldLog(Log.INFO))
            _log.info("Found by hash: " + state);
    }
    if (state == null) {
        if (queueIfMaxExceeded && _outboundStates.size() >= getMaxConcurrentEstablish()) {
            if (_queuedOutbound.size() >= MAX_QUEUED_OUTBOUND && !_queuedOutbound.containsKey(to)) {
                rejected = true;
            } else {
                List<OutNetMessage> newQueued = new ArrayList<OutNetMessage>(MAX_QUEUED_PER_PEER);
                List<OutNetMessage> queued = _queuedOutbound.putIfAbsent(to, newQueued);
                if (queued == null) {
                    queued = newQueued;
                    if (_log.shouldLog(Log.WARN))
                        _log.warn("Queueing outbound establish to " + to + ", increase " + PROP_MAX_CONCURRENT_ESTABLISH);
                }
                // There are still races possible but this should prevent AIOOBE and NPE
                synchronized (queued) {
                    queueCount = queued.size();
                    if (queueCount < MAX_QUEUED_PER_PEER) {
                        queued.add(msg);
                        // increment for the stat below
                        queueCount++;
                    } else {
                        rejected = true;
                    }
                    deferred = _queuedOutbound.size();
                }
            }
        } else {
            // must have a valid session key
            byte[] keyBytes = addr.getIntroKey();
            if (keyBytes == null) {
                _transport.markUnreachable(toHash);
                _transport.failed(msg, "Peer has no key, cannot establish");
                return;
            }
            SessionKey sessionKey;
            try {
                sessionKey = new SessionKey(keyBytes);
            } catch (IllegalArgumentException iae) {
                _transport.markUnreachable(toHash);
                _transport.failed(msg, "Peer has bad key, cannot establish");
                return;
            }
            boolean allowExtendedOptions = VersionComparator.comp(toRouterInfo.getVersion(), VERSION_ALLOW_EXTENDED_OPTIONS) >= 0 && !_context.getBooleanProperty(PROP_DISABLE_EXT_OPTS);
            // w/o ext options, it's always 'requested', no need to set
            // don't ask if they are indirect
            boolean requestIntroduction = allowExtendedOptions && !isIndirect && _transport.introducersMaybeRequired();
            state = new OutboundEstablishState(_context, maybeTo, to, toIdentity, allowExtendedOptions, requestIntroduction, sessionKey, addr, _transport.getDHFactory());
            OutboundEstablishState oldState = _outboundStates.putIfAbsent(to, state);
            boolean isNew = oldState == null;
            if (isNew) {
                if (isIndirect && maybeTo != null)
                    _outboundByClaimedAddress.put(maybeTo, state);
                if (_log.shouldLog(Log.DEBUG))
                    _log.debug("Adding new " + state);
            } else {
                // whoops, somebody beat us to it, throw out the state we just created
                state = oldState;
            }
        }
    }
    if (state != null) {
        state.addMessage(msg);
        List<OutNetMessage> queued = _queuedOutbound.remove(to);
        if (queued != null) {
            // see comments above
            synchronized (queued) {
                for (OutNetMessage m : queued) {
                    state.addMessage(m);
                }
            }
        }
    }
    if (rejected) {
        if (_log.shouldLog(Log.WARN))
            _log.warn("Too many pending, rejecting outbound establish to " + to);
        _transport.failed(msg, "Too many pending outbound connections");
        _context.statManager().addRateData("udp.establishRejected", deferred);
        return;
    }
    if (queueCount >= MAX_QUEUED_PER_PEER) {
        _transport.failed(msg, "Too many pending messages for the given peer");
        _context.statManager().addRateData("udp.establishOverflow", queueCount, deferred);
        return;
    }
    if (deferred > 0)
        msg.timestamp("too many deferred establishers");
    else if (state != null)
        msg.timestamp("establish state already waiting");
    notifyActivity();
}

Example 13 with RouterInfo

use of net.i2p.data.router.RouterInfo in project i2p.i2p by i2p.

the class IntroductionManager method pickInbound.

/**
 * Grab a bunch of peers who are willing to be introducers for us that
 * are locally known (duh) and have published their own SSU address (duh^2).
 * The picked peers have their info tacked on to the ssuOptions parameter for
 * use in the SSU RouterAddress.
 *
 * Try to use "good" peers (i.e. reachable, active)
 *
 * Also, ping all idle peers that were introducers in the last 2 hours,
 * to keep the connection up, since the netDb can have quite stale information,
 * and we want to keep our introducers valid.
 *
 * @param current current router address, may be null
 * @param ssuOptions out parameter, options are added
 * @return number of introducers added
 */
public int pickInbound(RouterAddress current, Properties ssuOptions, int howMany) {
    int start = _context.random().nextInt();
    if (_log.shouldLog(Log.DEBUG))
        _log.debug("Picking inbound out of " + _inbound.size());
    if (_inbound.isEmpty())
        return 0;
    List<PeerState> peers = new ArrayList<PeerState>(_inbound);
    int sz = peers.size();
    start = start % sz;
    int found = 0;
    long now = _context.clock().now();
    // 15 min
    long inactivityCutoff = now - (UDPTransport.EXPIRE_TIMEOUT / 2);
    // if not too many to choose from, be less picky
    if (sz <= howMany + 2)
        inactivityCutoff -= UDPTransport.EXPIRE_TIMEOUT / 4;
    List<Introducer> introducers = new ArrayList<Introducer>(howMany);
    for (int i = 0; i < sz && found < howMany; i++) {
        PeerState cur = peers.get((start + i) % sz);
        RouterInfo ri = _context.netDb().lookupRouterInfoLocally(cur.getRemotePeer());
        if (ri == null) {
            if (_log.shouldLog(Log.INFO))
                _log.info("Picked peer has no local routerInfo: " + cur);
            continue;
        }
        // FIXME we can include all his addresses including IPv6 even if we don't support IPv6 (isValid() is false)
        // but requires RelayRequest support, see below
        RouterAddress ra = _transport.getTargetAddress(ri);
        if (ra == null) {
            if (_log.shouldLog(Log.INFO))
                _log.info("Picked peer has no SSU address: " + ri);
            continue;
        }
        if (/* _context.profileOrganizer().isFailing(cur.getRemotePeer()) || */
        _context.banlist().isBanlisted(cur.getRemotePeer()) || _transport.wasUnreachable(cur.getRemotePeer())) {
            if (_log.shouldLog(Log.INFO))
                _log.info("Peer is failing, shistlisted or was unreachable: " + cur);
            continue;
        }
        // FIXED, was ||, is this OK now?
        if (cur.getLastReceiveTime() < inactivityCutoff && cur.getLastSendTime() < inactivityCutoff) {
            if (_log.shouldLog(Log.INFO))
                _log.info("Peer is idle too long: " + cur);
            continue;
        }
        // FIXME we can include all his addresses including IPv6 even if we don't support IPv6 (isValid() is false)
        // but requires RelayRequest support, see below
        byte[] ip = cur.getRemoteIP();
        int port = cur.getRemotePort();
        if (!isValid(ip, port))
            continue;
        if (_log.shouldLog(Log.INFO))
            _log.info("Picking introducer: " + cur);
        cur.setIntroducerTime();
        UDPAddress ura = new UDPAddress(ra);
        byte[] ikey = ura.getIntroKey();
        if (ikey == null)
            continue;
        introducers.add(new Introducer(ip, port, ikey, cur.getTheyRelayToUsAs()));
        found++;
    }
    // we sort them so a change in order only won't happen, and won't cause a republish
    Collections.sort(introducers);
    String exp = Long.toString((now + INTRODUCER_EXPIRATION) / 1000);
    for (int i = 0; i < found; i++) {
        Introducer in = introducers.get(i);
        ssuOptions.setProperty(UDPAddress.PROP_INTRO_HOST_PREFIX + i, in.sip);
        ssuOptions.setProperty(UDPAddress.PROP_INTRO_PORT_PREFIX + i, in.sport);
        ssuOptions.setProperty(UDPAddress.PROP_INTRO_KEY_PREFIX + i, in.skey);
        ssuOptions.setProperty(UDPAddress.PROP_INTRO_TAG_PREFIX + i, in.stag);
        String sexp = exp;
        // and reuse if still recent enough, so deepEquals() won't fail in UDPT.rEA
        if (current != null) {
            for (int j = 0; j < UDPTransport.PUBLIC_RELAY_COUNT; j++) {
                if (in.sip.equals(current.getOption(UDPAddress.PROP_INTRO_HOST_PREFIX + j)) && in.sport.equals(current.getOption(UDPAddress.PROP_INTRO_PORT_PREFIX + j)) && in.skey.equals(current.getOption(UDPAddress.PROP_INTRO_KEY_PREFIX + j)) && in.stag.equals(current.getOption(UDPAddress.PROP_INTRO_TAG_PREFIX + j))) {
                    // found old one
                    String oexp = current.getOption(UDPAddress.PROP_INTRO_EXP_PREFIX + j);
                    if (oexp != null) {
                        try {
                            long oex = Long.parseLong(oexp) * 1000;
                            if (oex > now + UDPTransport.INTRODUCER_EXPIRATION_MARGIN) {
                                // still good, use old expiration time
                                sexp = oexp;
                            }
                        } catch (NumberFormatException nfe) {
                        }
                    }
                    break;
                }
            }
        }
        ssuOptions.setProperty(UDPAddress.PROP_INTRO_EXP_PREFIX + i, sexp);
    }
    // FIXME failsafe if found == 0, relax inactivityCutoff and try again?
    pingIntroducers();
    return found;
}

Example 14 with RouterInfo

use of net.i2p.data.router.RouterInfo in project i2p.i2p by i2p.

the class NTCPTransport method bid.

public TransportBid bid(RouterInfo toAddress, long dataSize) {
    if (!isAlive())
        return null;
    if (dataSize > NTCPConnection.MAX_MSG_SIZE) {
        // let SSU deal with it
        _context.statManager().addRateData("ntcp.noBidTooLargeI2NP", dataSize);
        return null;
    }
    Hash peer = toAddress.getIdentity().calculateHash();
    if (_context.banlist().isBanlisted(peer, STYLE)) {
        // we aren't banlisted in general (since we are trying to get a bid), but we have
        // recently banlisted the peer on the NTCP transport, so don't try it
        _context.statManager().addRateData("ntcp.attemptBanlistedPeer", 1);
        return null;
    } else if (isUnreachable(peer)) {
        _context.statManager().addRateData("ntcp.attemptUnreachablePeer", 1);
        return null;
    }
    boolean established = isEstablished(toAddress.getIdentity());
    if (established) {
        // _log.debug("fast bid when trying to send to " + peer + " as its already established");
        return _fastBid;
    }
    RouterAddress addr = getTargetAddress(toAddress);
    if (addr == null) {
        markUnreachable(peer);
        return null;
    }
    // Check for supported sig type
    SigType type = toAddress.getIdentity().getSigType();
    if (type == null || !type.isAvailable()) {
        markUnreachable(peer);
        return null;
    }
    // Can we connect to them if we are not DSA?
    RouterInfo us = _context.router().getRouterInfo();
    if (us != null) {
        RouterIdentity id = us.getIdentity();
        if (id.getSigType() != SigType.DSA_SHA1) {
            String v = toAddress.getVersion();
            if (VersionComparator.comp(v, MIN_SIGTYPE_VERSION) < 0) {
                markUnreachable(peer);
                return null;
            }
        }
    }
    if (!allowConnection()) {
        // _log.warn("no bid when trying to send to " + peer + ", max connection limit reached");
        return _transientFail;
    }
    // _log.debug("slow bid when trying to send to " + peer);
    if (haveCapacity()) {
        if (addr.getCost() > DEFAULT_COST)
            return _slowCostBid;
        else
            return _slowBid;
    } else {
        if (addr.getCost() > DEFAULT_COST)
            return _nearCapacityCostBid;
        else
            return _nearCapacityBid;
    }
}

Example 15 with RouterInfo

use of net.i2p.data.router.RouterInfo in project i2p.i2p by i2p.

the class BuildHandler method handleReq.

/**
 * If we are dropping lots of requests before even trying to handle them,
 * I suppose you could call us "overloaded"
 */
/**
 ** unused, see handleReq() below
 *    private final static int MAX_PROACTIVE_DROPS = 240;
 *
 *    private int countProactiveDrops() {
 *        int dropped = 0;
 *        dropped += countEvents("tunnel.dropLoadProactive", 60*1000);
 *        dropped += countEvents("tunnel.dropLoad", 60*1000);
 *        dropped += countEvents("tunnel.dropLoadBacklog", 60*1000);
 *        dropped += countEvents("tunnel.dropLoadDelay", 60*1000);
 *        return dropped;
 *    }
 *
 *    private int countEvents(String stat, long period) {
 *        RateStat rs = _context.statManager().getRate(stat);
 *        if (rs != null) {
 *            Rate r = rs.getRate(period);
 *            if (r != null)
 *                return (int)r.getCurrentEventCount();
 *        }
 *        return 0;
 *    }
 ***
 */
/**
 *  Actually process the request and send the reply.
 *
 *  Todo: Replies are not subject to RED for bandwidth reasons,
 *  and the bandwidth is not credited to any tunnel.
 *  If we did credit the reply to the tunnel, it would
 *  prevent the classification of the tunnel as 'inactive' on tunnels.jsp.
 */
private void handleReq(RouterInfo nextPeerInfo, BuildMessageState state, BuildRequestRecord req, Hash nextPeer) {
    long ourId = req.readReceiveTunnelId();
    long nextId = req.readNextTunnelId();
    boolean isInGW = req.readIsInboundGateway();
    boolean isOutEnd = req.readIsOutboundEndpoint();
    Hash from = state.fromHash;
    if (from == null && state.from != null)
        from = state.from.calculateHash();
    if (isInGW && isOutEnd) {
        _context.statManager().addRateData("tunnel.rejectHostile", 1);
        _log.error("Dropping build request, IBGW+OBEP: " + req);
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        return;
    }
    if (ourId <= 0 || ourId > TunnelId.MAX_ID_VALUE || nextId <= 0 || nextId > TunnelId.MAX_ID_VALUE) {
        _context.statManager().addRateData("tunnel.rejectHostile", 1);
        if (_log.shouldWarn())
            _log.warn("Dropping build request, bad tunnel ID: " + req);
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        return;
    }
    // Loop checks
    if ((!isOutEnd) && _context.routerHash().equals(nextPeer)) {
        _context.statManager().addRateData("tunnel.rejectHostile", 1);
        // old i2pd
        if (_log.shouldWarn())
            _log.warn("Dropping build request, we are the next hop: " + req);
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        return;
    }
    if (!isInGW) {
        // but if not, something is seriously wrong here.
        if (from == null || _context.routerHash().equals(from)) {
            _context.statManager().addRateData("tunnel.rejectHostile", 1);
            if (_log.shouldWarn())
                _log.warn("Dropping build request, we are the previous hop: " + req);
            return;
        }
    }
    if ((!isOutEnd) && (!isInGW)) {
        // A-B-C-A is not preventable
        if (nextPeer.equals(from)) {
            // i2pd does this
            _context.statManager().addRateData("tunnel.rejectHostile", 1);
            if (_log.shouldLog(Log.WARN))
                _log.warn("Dropping build request with the same previous and next hop: " + req);
            _context.commSystem().mayDisconnect(from);
            return;
        }
    }
    // time is in hours, rounded down.
    // tunnel-alt-creation.html specifies that this is enforced +/- 1 hour but it was not.
    // As of 0.9.16, allow + 5 minutes to - 65 minutes.
    long time = req.readRequestTime();
    long now = (_context.clock().now() / (60l * 60l * 1000l)) * (60 * 60 * 1000);
    long timeDiff = now - time;
    if (timeDiff > MAX_REQUEST_AGE) {
        _context.statManager().addRateData("tunnel.rejectTooOld", 1);
        if (_log.shouldLog(Log.WARN))
            _log.warn("Dropping build request too old... replay attack? " + DataHelper.formatDuration(timeDiff) + ": " + req);
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        return;
    }
    if (timeDiff < 0 - MAX_REQUEST_FUTURE) {
        _context.statManager().addRateData("tunnel.rejectFuture", 1);
        if (_log.shouldLog(Log.WARN))
            _log.warn("Dropping build request too far in future " + DataHelper.formatDuration(0 - timeDiff) + ": " + req);
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        return;
    }
    int response;
    if (_context.router().isHidden()) {
        _context.throttle().setTunnelStatus(_x("Rejecting tunnels: Hidden mode"));
        response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
    } else {
        response = _context.throttle().acceptTunnelRequest();
    }
    // This only checked OUR tunnels, so the log message was wrong.
    // Now checked by TunnelDispatcher.joinXXX()
    // and returned as success value, checked below.
    // if (_context.tunnelManager().getTunnelInfo(new TunnelId(ourId)) != null) {
    // if (_log.shouldLog(Log.ERROR))
    // _log.error("Already participating in a tunnel with the given Id (" + ourId + "), so gotta reject");
    // if (response == 0)
    // response = TunnelHistory.TUNNEL_REJECT_PROBABALISTIC_REJECT;
    // }
    // if ( (response == 0) && (_context.random().nextInt(50) <= 1) )
    // response = TunnelHistory.TUNNEL_REJECT_PROBABALISTIC_REJECT;
    long recvDelay = _context.clock().now() - state.recvTime;
    if (response == 0) {
        // unused
        // int proactiveDrops = countProactiveDrops();
        float pDrop = ((float) recvDelay) / (float) (BuildRequestor.REQUEST_TIMEOUT * 3);
        pDrop = (float) Math.pow(pDrop, 16);
        if (_context.random().nextFloat() < pDrop) {
            // || (proactiveDrops > MAX_PROACTIVE_DROPS) ) ) {
            _context.statManager().addRateData("tunnel.rejectOverloaded", recvDelay);
            _context.throttle().setTunnelStatus(_x("Rejecting tunnels: Request overload"));
            // if (true || (proactiveDrops < MAX_PROACTIVE_DROPS*2))
            response = TunnelHistory.TUNNEL_REJECT_TRANSIENT_OVERLOAD;
        // else
        // response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
        } else {
            _context.statManager().addRateData("tunnel.acceptLoad", recvDelay);
        }
    }
    /*
         * Being a IBGW or OBEP generally leads to more connections, so if we are
         * approaching our connection limit (i.e. !haveCapacity()),
         * reject this request.
         *
         * Don't do this for class N or O, under the assumption that they are already talking
         * to most of the routers, so there's no reason to reject. This may drive them
         * to their conn. limits, but it's hopefully a temporary solution to the
         * tunnel build congestion. As the net grows this will have to be revisited.
         */
    RouterInfo ri = _context.router().getRouterInfo();
    if (response == 0) {
        if (ri == null) {
            // ?? We should always have a RI
            response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
        } else {
            char bw = ri.getBandwidthTier().charAt(0);
            if (bw != 'O' && bw != 'N' && bw != 'P' && bw != 'X' && ((isInGW && !_context.commSystem().haveInboundCapacity(87)) || (isOutEnd && !_context.commSystem().haveOutboundCapacity(87)))) {
                _context.statManager().addRateData("tunnel.rejectConnLimits", 1);
                _context.throttle().setTunnelStatus(_x("Rejecting tunnels: Connection limit"));
                response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
            }
        }
    }
    // We may need another counter above for requests.
    if (response == 0 && !isInGW) {
        if (from != null && _throttler.shouldThrottle(from)) {
            if (_log.shouldLog(Log.WARN))
                _log.warn("Rejecting tunnel (hop throttle), previous hop: " + from + ": " + req);
            // no setTunnelStatus() indication
            _context.statManager().addRateData("tunnel.rejectHopThrottle", 1);
            response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
        }
    }
    if (response == 0 && (!isOutEnd) && _throttler.shouldThrottle(nextPeer)) {
        if (_log.shouldLog(Log.WARN))
            _log.warn("Rejecting tunnel (hop throttle), next hop: " + req);
        _context.statManager().addRateData("tunnel.rejectHopThrottle", 1);
        // no setTunnelStatus() indication
        response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
    }
    HopConfig cfg = null;
    if (response == 0) {
        cfg = new HopConfig();
        cfg.setCreation(_context.clock().now());
        cfg.setExpiration(_context.clock().now() + 10 * 60 * 1000);
        cfg.setIVKey(req.readIVKey());
        cfg.setLayerKey(req.readLayerKey());
        if (isInGW) {
        // default
        // cfg.setReceiveFrom(null);
        } else {
            if (from != null) {
                cfg.setReceiveFrom(from);
            } else {
                // b0rk
                return;
            }
        }
        cfg.setReceiveTunnelId(DataHelper.toLong(4, ourId));
        if (isOutEnd) {
        // default
        // cfg.setSendTo(null);
        // cfg.setSendTunnelId(null);
        } else {
            cfg.setSendTo(nextPeer);
            cfg.setSendTunnelId(DataHelper.toLong(4, nextId));
        }
        // now "actually" join
        boolean success;
        if (isOutEnd)
            success = _context.tunnelDispatcher().joinOutboundEndpoint(cfg);
        else if (isInGW)
            success = _context.tunnelDispatcher().joinInboundGateway(cfg);
        else
            success = _context.tunnelDispatcher().joinParticipant(cfg);
        if (success) {
            if (_log.shouldLog(Log.DEBUG))
                _log.debug("Joining: " + req);
        } else {
            // Dup Tunnel ID. This can definitely happen (birthday paradox).
            // Probability in 11 minutes (per hop type):
            // 0.1% for 2900 tunnels; 1% for 9300 tunnels
            response = TunnelHistory.TUNNEL_REJECT_BANDWIDTH;
            _context.statManager().addRateData("tunnel.rejectDupID", 1);
            if (_log.shouldLog(Log.WARN))
                _log.warn("DUP ID failure: " + req);
        }
    }
    if (response != 0) {
        _context.statManager().addRateData("tunnel.reject." + response, 1);
        _context.messageHistory().tunnelRejected(from, new TunnelId(ourId), nextPeer, // (isOutEnd ? "outbound endpoint" : isInGW ? "inbound gw" : "participant"));
        Integer.toString(response));
        if (from != null)
            _context.commSystem().mayDisconnect(from);
        // 81% = between 75% control measures in Transports and 87% rejection above
        if ((!_context.routerHash().equals(nextPeer)) && (!_context.commSystem().haveOutboundCapacity(81)) && (!_context.commSystem().isEstablished(nextPeer))) {
            _context.statManager().addRateData("tunnel.dropConnLimits", 1);
            if (_log.shouldLog(Log.WARN))
                _log.warn("Not sending rejection due to conn limits: " + req);
            return;
        }
    } else if (isInGW && from != null) {
        // we're the start of the tunnel, no use staying connected
        _context.commSystem().mayDisconnect(from);
    }
    if (_log.shouldLog(Log.DEBUG))
        _log.debug("Responding to " + state.msg.getUniqueId() + " after " + recvDelay + " with " + response + " from " + (from != null ? from : "tunnel") + ": " + req);
    EncryptedBuildRecord reply = BuildResponseRecord.create(_context, response, req.readReplyKey(), req.readReplyIV(), state.msg.getUniqueId());
    int records = state.msg.getRecordCount();
    int ourSlot = -1;
    for (int j = 0; j < records; j++) {
        if (state.msg.getRecord(j) == null) {
            ourSlot = j;
            state.msg.setRecord(j, reply);
            // + ": " + Base64.encode(reply));
            break;
        }
    }
    if (_log.shouldLog(Log.DEBUG))
        _log.debug("Read slot " + ourSlot + " containing: " + req + " accepted? " + response + " recvDelay " + recvDelay + " replyMessage " + req.readReplyMessageId());
    // now actually send the response
    long expires = _context.clock().now() + NEXT_HOP_SEND_TIMEOUT;
    if (!isOutEnd) {
        state.msg.setUniqueId(req.readReplyMessageId());
        state.msg.setMessageExpiration(expires);
        OutNetMessage msg = new OutNetMessage(_context, state.msg, expires, PRIORITY, nextPeerInfo);
        if (response == 0)
            msg.setOnFailedSendJob(new TunnelBuildNextHopFailJob(_context, cfg));
        _context.outNetMessagePool().add(msg);
    } else {
        // We are the OBEP.
        // send it to the reply tunnel on the reply peer within a new TunnelBuildReplyMessage
        // (enough layers jrandom?)
        TunnelBuildReplyMessage replyMsg;
        if (records == TunnelBuildMessage.MAX_RECORD_COUNT)
            replyMsg = new TunnelBuildReplyMessage(_context);
        else
            replyMsg = new VariableTunnelBuildReplyMessage(_context, records);
        for (int i = 0; i < records; i++) replyMsg.setRecord(i, state.msg.getRecord(i));
        replyMsg.setUniqueId(req.readReplyMessageId());
        replyMsg.setMessageExpiration(expires);
        TunnelGatewayMessage m = new TunnelGatewayMessage(_context);
        m.setMessage(replyMsg);
        m.setMessageExpiration(expires);
        m.setTunnelId(new TunnelId(nextId));
        if (_context.routerHash().equals(nextPeer)) {
            // ok, we are the gateway, so inject it
            if (_log.shouldLog(Log.DEBUG))
                _log.debug("We are the reply gateway for " + nextId + " when replying to replyMessage " + req);
            _context.tunnelDispatcher().dispatch(m);
        } else {
            // ok, the gateway is some other peer, shove 'er across
            OutNetMessage outMsg = new OutNetMessage(_context, m, expires, PRIORITY, nextPeerInfo);
            if (response == 0)
                outMsg.setOnFailedSendJob(new TunnelBuildNextHopFailJob(_context, cfg));
            _context.outNetMessagePool().add(outMsg);
        }
    }
}