bgp/rib-impl/src/main/java/org/opendaylight/protocol/bgp/rib/impl/AbstractBGPSessionNegotiator.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.protocol.bgp.rib.impl;
  10
  11 import com.google.common.annotations.VisibleForTesting;
  12 import com.google.common.base.Preconditions;
  13 import io.netty.channel.Channel;
  14 import io.netty.channel.ChannelFuture;
  15 import io.netty.channel.ChannelFutureListener;
  16 import io.netty.channel.ChannelHandlerContext;
  17 import io.netty.channel.ChannelInboundHandlerAdapter;
  18 import io.netty.util.concurrent.Promise;
  19 import io.netty.util.concurrent.ScheduledFuture;
  20 import java.util.concurrent.TimeUnit;
  21 import javax.annotation.concurrent.GuardedBy;
  22 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  23 import org.opendaylight.protocol.bgp.parser.BGPError;
  24 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPPeerRegistry;
  25 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences;
  26 import org.opendaylight.protocol.bgp.rib.spi.BGPSessionListener;
  27 import org.opendaylight.protocol.bgp.rib.spi.SessionNegotiator;
  28 import org.opendaylight.protocol.util.Ipv6Util;
  29 import org.opendaylight.protocol.util.Values;
  30 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddress;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder;
  38 import org.opendaylight.yangtools.yang.binding.Notification;
  39 import org.slf4j.Logger;
  40 import org.slf4j.LoggerFactory;
  41
  42 /**
  43  * Bgp Session negotiator. Common for local-to-remote and remote-to-local connections.
  44  * One difference is session validation performed by injected BGPSessionValidator when OPEN message is received.
  45  */
  46 abstract class AbstractBGPSessionNegotiator extends ChannelInboundHandlerAdapter implements SessionNegotiator {
  47     // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  48     private static final int INITIAL_HOLDTIMER = 4;
  49
  50     /**
  51      * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  52      */
  53     private static final int AS_TRANS = 23456;
  54
  55     @VisibleForTesting
  56     public enum State {
  57         /**
  58          * Negotiation has not started yet.
  59          */
  60         IDLE,
  61         /**
  62          * We have sent our Open message, and are waiting for the peer's Open message.
  63          */
  64         OPEN_SENT,
  65         /**
  66          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  67          * Open message.
  68          */
  69         OPEN_CONFIRM,
  70         /**
  71          * The negotiation finished.
  72          */
  73         FINISHED,
  74     }
  75
  76     private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class);
  77     private final BGPPeerRegistry registry;
  78     private final Promise<BGPSessionImpl> promise;
  79     private final Channel channel;
  80     @GuardedBy("this")
  81     private State state = State.IDLE;
  82     @GuardedBy("this")
  83     private BGPSessionImpl session;
  84     @GuardedBy("this")
  85     private ScheduledFuture<?> pending;
  86
  87     AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  88             final BGPPeerRegistry registry) {
  89         this.promise = Preconditions.checkNotNull(promise);
  90         this.channel = Preconditions.checkNotNull(channel);
  91         this.registry = registry;
  92     }
  93
  94     private synchronized void startNegotiation() {
  95         if (!(this.state == State.IDLE || this.state == State.OPEN_CONFIRM)) {
  96             return;
  97         }
  98         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  99         final IpAddress remoteIp = getRemoteIp();
 100         try {
 101             // Check if peer is configured in registry before retrieving preferences
 102             if (!this.registry.isPeerConfigured(remoteIp)) {
 103                 final BGPDocumentedException cause = new BGPDocumentedException(
 104                     String.format("BGP peer with ip: %s not configured, check configured peers in : %s", remoteIp, this.registry), BGPError.CONNECTION_REJECTED);
 105                 negotiationFailed(cause);
 106                 return;
 107             }
 108
 109             final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 110
 111             int as = preferences.getMyAs().getValue().intValue();
 112             // Set as AS_TRANS if the value is bigger than 2B
 113             if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 114                 as = AS_TRANS;
 115             }
 116             sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 117                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 118             if (this.state != State.FINISHED) {
 119                 this.state = State.OPEN_SENT;
 120                 this.pending = this.channel.eventLoop().schedule(() -> {
 121                     synchronized (AbstractBGPSessionNegotiator.this) {
 122                         AbstractBGPSessionNegotiator.this.pending = null;
 123                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 124                             AbstractBGPSessionNegotiator.this
 125                                 .sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 126                             negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 127                             AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 128                         }
 129                     }
 130                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 131             }
 132         } catch (final Exception e) {
 133             LOG.warn("Unexpected negotiation failure", e);
 134             negotiationFailedCloseChannel(e);
 135         }
 136     }
 137
 138     private IpAddress getRemoteIp() {
 139         final IpAddress remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 140         if (remoteIp.getIpv6Address() != null) {
 141             return new IpAddress(Ipv6Util.getFullForm(remoteIp.getIpv6Address()));
 142         }
 143         return remoteIp;
 144     }
 145
 146     protected synchronized void handleMessage(final Notification msg) {
 147         LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg);
 148         switch (this.state) {
 149         case FINISHED:
 150             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 151             return;
 152         case IDLE:
 153             // to avoid race condition when Open message was sent by the peer before startNegotiation could be executed
 154             if (msg instanceof Open) {
 155                 startNegotiation();
 156                 handleOpen((Open) msg);
 157                 return;
 158             }
 159             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 160             break;
 161         case OPEN_CONFIRM:
 162             if (msg instanceof Keepalive) {
 163                 negotiationSuccessful(this.session);
 164                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 165             } else if (msg instanceof Notify) {
 166                 final Notify ntf = (Notify) msg;
 167                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 168             }
 169             this.state = State.FINISHED;
 170             return;
 171         case OPEN_SENT:
 172             if (msg instanceof Open) {
 173                 handleOpen((Open) msg);
 174                 return;
 175             }
 176             break;
 177         default:
 178             break;
 179         }
 180
 181         // Catch-all for unexpected message
 182         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 183         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 184         negotiationFailed(new BGPDocumentedException("Unexpected message channel: " + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR));
 185         this.state = State.FINISHED;
 186     }
 187
 188     private static Notify buildErrorNotify(final BGPError err) {
 189         return buildErrorNotify(err, null);
 190     }
 191
 192     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 193         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 194         if (data != null && data.length != 0) {
 195             builder.setData(data);
 196         }
 197         return builder.build();
 198     }
 199
 200     private synchronized void handleOpen(final Open openObj) {
 201         final IpAddress remoteIp = getRemoteIp();
 202         final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 203         try {
 204             final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences), getDestinationId(openObj, preferences), openObj);
 205             sendMessage(new KeepaliveBuilder().build());
 206             this.state = State.OPEN_CONFIRM;
 207             this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry);
 208             this.session.setChannelExtMsgCoder(openObj);
 209             LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", this.channel, openObj);
 210         } catch (final BGPDocumentedException e) {
 211             LOG.warn("Channel {} negotiation failed", this.channel, e);
 212             negotiationFailed(e);
 213         }
 214     }
 215
 216     private synchronized void negotiationFailed(final Throwable e) {
 217         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 218         if (e instanceof BGPDocumentedException) {
 219             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 220             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 221             sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 222         }
 223         if (this.state == State.OPEN_CONFIRM) {
 224             this.registry.removePeerSession(getRemoteIp());
 225         }
 226         negotiationFailedCloseChannel(e);
 227         this.state = State.FINISHED;
 228     }
 229
 230     /**
 231      * @param openMsg Open message received from remote BGP speaker
 232      * @param preferences Local BGP speaker preferences
 233      * @return BGP Id of device that accepted the connection
 234      */
 235     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 236
 237     /**
 238      * @param openMsg Open message received from remote BGP speaker
 239      * @param preferences Local BGP speaker preferences
 240      * @return BGP Id of device that accepted the connection
 241      */
 242     protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences);
 243
 244     public synchronized State getState() {
 245         return this.state;
 246     }
 247
 248     private void negotiationSuccessful(final BGPSessionImpl session) {
 249         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 250         this.channel.pipeline().replace(this, "session", session);
 251         this.promise.setSuccess(session);
 252     }
 253
 254     private void negotiationFailedCloseChannel(final Throwable cause) {
 255         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 256         this.channel.close();
 257         synchronized (AbstractBGPSessionNegotiator.this) {
 258             if (this.pending != null && this.pending.isCancellable()) {
 259                 this.pending.cancel(true);
 260                 this.pending = null;
 261             }
 262         }
 263     }
 264
 265     private void sendMessage(final Notification msg) {
 266         this.channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 267             if (!f.isSuccess()) {
 268                 LOG.warn("Failed to send message {} to channel {}", msg,  AbstractBGPSessionNegotiator.this.channel, f.cause());
 269                 negotiationFailedCloseChannel(f.cause());
 270             } else {
 271                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 272             }
 273         });
 274     }
 275
 276     @Override
 277     public final void channelActive(final ChannelHandlerContext ctx) {
 278         LOG.debug("Starting session negotiation on channel {}", this.channel);
 279         startNegotiation();
 280     }
 281
 282     @Override
 283     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 284         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 285         try {
 286             handleMessage((Notification) msg);
 287         } catch (final Exception e) {
 288             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 289             negotiationFailedCloseChannel(e);
 290         }
 291
 292     }
 293
 294     @Override
 295     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 296         LOG.info("Unexpected error during negotiation", cause);
 297         negotiationFailedCloseChannel(cause);
 298     }
 299 }