Java tutorial
/* * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.protocol.bgp.rib.impl; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Preconditions; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.util.concurrent.Promise; import java.util.concurrent.TimeUnit; import javax.annotation.concurrent.GuardedBy; import org.opendaylight.protocol.bgp.parser.BGPDocumentedException; import org.opendaylight.protocol.bgp.parser.BGPError; import org.opendaylight.protocol.bgp.rib.impl.spi.BGPPeerRegistry; import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences; import org.opendaylight.protocol.bgp.rib.spi.BGPSessionListener; import org.opendaylight.protocol.bgp.rib.spi.SessionNegotiator; import org.opendaylight.protocol.util.Ipv6Util; import org.opendaylight.protocol.util.Values; import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddress; import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder; import org.opendaylight.yangtools.yang.binding.Notification; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Bgp Session negotiator. Common for local-to-remote and remote-to-local connections. * One difference is session validation performed by injected BGPSessionValidator when OPEN message is received. */ abstract class AbstractBGPSessionNegotiator extends ChannelInboundHandlerAdapter implements SessionNegotiator { // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2 private static final int INITIAL_HOLDTIMER = 4; /** * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a> */ private static final int AS_TRANS = 23456; @VisibleForTesting public enum State { /** * Negotiation has not started yet. */ IDLE, /** * We have sent our Open message, and are waiting for the peer's Open message. */ OPEN_SENT, /** * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our * Open message. */ OPEN_CONFIRM, /** * The negotiation finished. */ FINISHED, } private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class); private final BGPPeerRegistry registry; private final Promise<BGPSessionImpl> promise; private final Channel channel; @GuardedBy("this") private State state = State.IDLE; @GuardedBy("this") private BGPSessionImpl session; AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel, final BGPPeerRegistry registry) { this.promise = Preconditions.checkNotNull(promise); this.channel = Preconditions.checkNotNull(channel); this.registry = registry; } private synchronized void startNegotiation() { if (!(this.state == State.IDLE || this.state == State.OPEN_CONFIRM)) { return; } // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM) final IpAddress remoteIp = getRemoteIp(); try { // Check if peer is configured in registry before retrieving preferences if (!this.registry.isPeerConfigured(remoteIp)) { final BGPDocumentedException cause = new BGPDocumentedException( String.format("BGP peer with ip: %s not configured, check configured peers in : %s", remoteIp, this.registry), BGPError.CONNECTION_REJECTED); negotiationFailed(cause); return; } final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp); int as = preferences.getMyAs().getValue().intValue(); // Set as AS_TRANS if the value is bigger than 2B if (as > Values.UNSIGNED_SHORT_MAX_VALUE) { as = AS_TRANS; } sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()) .setBgpIdentifier(preferences.getBgpId()).setBgpParameters(preferences.getParams()).build()); if (this.state != State.FINISHED) { this.state = State.OPEN_SENT; this.channel.eventLoop().schedule(new Runnable() { @Override public void run() { synchronized (AbstractBGPSessionNegotiator.this) { if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) { AbstractBGPSessionNegotiator.this .sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED)); negotiationFailed( new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR)); AbstractBGPSessionNegotiator.this.state = State.FINISHED; } } } }, INITIAL_HOLDTIMER, TimeUnit.MINUTES); } } catch (final Exception e) { LOG.warn("Unexpected negotiation failure", e); negotiationFailedCloseChannel(e); } } private IpAddress getRemoteIp() { final IpAddress remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress()); if (remoteIp.getIpv6Address() != null) { return new IpAddress(Ipv6Util.getFullForm(remoteIp.getIpv6Address())); } return remoteIp; } protected synchronized void handleMessage(final Notification msg) { LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg); switch (this.state) { case FINISHED: sendMessage(buildErrorNotify(BGPError.FSM_ERROR)); return; case IDLE: // to avoid race condition when Open message was sent by the peer before startNegotiation could be executed if (msg instanceof Open) { startNegotiation(); handleOpen((Open) msg); return; } sendMessage(buildErrorNotify(BGPError.FSM_ERROR)); break; case OPEN_CONFIRM: if (msg instanceof Keepalive) { negotiationSuccessful(this.session); LOG.info("BGP Session with peer {} established successfully.", this.channel); } else if (msg instanceof Notify) { final Notify ntf = (Notify) msg; negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode()))); } this.state = State.FINISHED; return; case OPEN_SENT: if (msg instanceof Open) { handleOpen((Open) msg); return; } break; default: break; } // Catch-all for unexpected message LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg); sendMessage(buildErrorNotify(BGPError.FSM_ERROR)); negotiationFailed(new BGPDocumentedException( "Unexpected message channel: " + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR)); this.state = State.FINISHED; } private static Notify buildErrorNotify(final BGPError err) { return buildErrorNotify(err, null); } private static Notify buildErrorNotify(final BGPError err, final byte[] data) { final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()) .setErrorSubcode(err.getSubcode()); if (data != null && data.length != 0) { builder.setData(data); } return builder.build(); } private synchronized void handleOpen(final Open openObj) { final IpAddress remoteIp = getRemoteIp(); final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp); try { final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences), getDestinationId(openObj, preferences), openObj); sendMessage(new KeepaliveBuilder().build()); this.state = State.OPEN_CONFIRM; this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry); this.session.setChannelExtMsgCoder(openObj); LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", this.channel, openObj); } catch (final BGPDocumentedException e) { LOG.warn("Channel {} negotiation failed", this.channel, e); negotiationFailed(e); } } private synchronized void negotiationFailed(final Throwable e) { LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage()); if (e instanceof BGPDocumentedException) { // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException). sendMessage(buildErrorNotify(((BGPDocumentedException) e).getError(), ((BGPDocumentedException) e).getData())); } if (this.state == State.OPEN_CONFIRM) { this.registry.removePeerSession(getRemoteIp()); } negotiationFailedCloseChannel(e); this.state = State.FINISHED; } /** * @param openMsg Open message received from remote BGP speaker * @param preferences Local BGP speaker preferences * @return BGP Id of device that accepted the connection */ protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences); /** * @param openMsg Open message received from remote BGP speaker * @param preferences Local BGP speaker preferences * @return BGP Id of device that accepted the connection */ protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences); public synchronized State getState() { return this.state; } private void negotiationSuccessful(final BGPSessionImpl session) { LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session); this.channel.pipeline().replace(this, "session", session); this.promise.setSuccess(session); } private void negotiationFailedCloseChannel(final Throwable cause) { LOG.debug("Negotiation on channel {} failed", this.channel, cause); this.channel.close(); this.promise.setFailure(cause); } private void sendMessage(final Notification msg) { this.channel.writeAndFlush(msg).addListener(new ChannelFutureListener() { @Override public void operationComplete(final ChannelFuture f) { if (!f.isSuccess()) { LOG.warn("Failed to send message {} to channel {}", msg, AbstractBGPSessionNegotiator.this.channel, f.cause()); negotiationFailedCloseChannel(f.cause()); } else { LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel); } } }); } @Override public final void channelActive(final ChannelHandlerContext ctx) { LOG.debug("Starting session negotiation on channel {}", this.channel); startNegotiation(); } @Override public final void channelRead(final ChannelHandlerContext ctx, final Object msg) { LOG.debug("Negotiation read invoked on channel {}", this.channel); try { handleMessage((Notification) msg); } catch (final Exception e) { LOG.debug("Unexpected error while handling negotiation message {}", msg, e); negotiationFailedCloseChannel(e); } } @Override public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) { LOG.info("Unexpected error during negotiation", cause); negotiationFailedCloseChannel(cause); } }