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

   1 /*
   2  * Copyright (c) 2013 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 package org.opendaylight.protocol.bgp.rib.impl;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.MoreObjects;
  12 import com.google.common.base.MoreObjects.ToStringHelper;
  13 import com.google.common.base.Optional;
  14 import com.google.common.base.Preconditions;
  15 import com.google.common.collect.Lists;
  16 import com.google.common.collect.Sets;
  17 import io.netty.buffer.ByteBufUtil;
  18 import io.netty.channel.Channel;
  19 import io.netty.channel.ChannelFuture;
  20 import io.netty.channel.ChannelFutureListener;
  21 import io.netty.channel.ChannelHandlerContext;
  22 import io.netty.channel.ChannelPipeline;
  23 import io.netty.channel.SimpleChannelInboundHandler;
  24 import java.io.IOException;
  25 import java.nio.channels.NonWritableChannelException;
  26 import java.util.Collections;
  27 import java.util.Date;
  28 import java.util.List;
  29 import java.util.Set;
  30 import java.util.concurrent.TimeUnit;
  31 import javax.annotation.concurrent.GuardedBy;
  32 import org.opendaylight.controller.config.yang.bgp.rib.impl.BgpSessionState;
  33 import org.opendaylight.protocol.bgp.parser.AsNumberUtil;
  34 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  35 import org.opendaylight.protocol.bgp.parser.BGPError;
  36 import org.opendaylight.protocol.bgp.parser.BgpExtendedMessageUtil;
  37 import org.opendaylight.protocol.bgp.parser.BgpTableTypeImpl;
  38 import org.opendaylight.protocol.bgp.parser.spi.MultiPathSupport;
  39 import org.opendaylight.protocol.bgp.parser.spi.pojo.MultiPathSupportImpl;
  40 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPMessagesListener;
  41 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPPeerRegistry;
  42 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences;
  43 import org.opendaylight.protocol.bgp.rib.impl.state.BGPSessionStateImpl;
  44 import org.opendaylight.protocol.bgp.rib.impl.state.BGPSessionStateProvider;
  45 import org.opendaylight.protocol.bgp.rib.impl.stats.peer.BGPSessionStats;
  46 import org.opendaylight.protocol.bgp.rib.impl.stats.peer.BGPSessionStatsImpl;
  47 import org.opendaylight.protocol.bgp.rib.spi.BGPSession;
  48 import org.opendaylight.protocol.bgp.rib.spi.BGPSessionListener;
  49 import org.opendaylight.protocol.bgp.rib.spi.BGPTerminationReason;
  50 import org.opendaylight.protocol.bgp.rib.spi.State;
  51 import org.opendaylight.protocol.bgp.rib.spi.state.BGPSessionState;
  52 import org.opendaylight.protocol.bgp.rib.spi.state.BGPTimersState;
  53 import org.opendaylight.protocol.bgp.rib.spi.state.BGPTransportState;
  54 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.AsNumber;
  55 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  58 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  59 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  60 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  61 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Update;
  62 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.open.message.BgpParameters;
  63 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.open.message.bgp.parameters.OptionalCapabilities;
  64 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.open.message.bgp.parameters.optional.capabilities.CParameters;
  65 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.BgpTableType;
  66 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.CParameters1;
  67 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.RouteRefresh;
  68 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.mp.capabilities.AddPathCapability;
  69 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.mp.capabilities.MultiprotocolCapability;
  70 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.mp.capabilities.add.path.capability.AddressFamilies;
  71 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.rib.rev130925.rib.TablesKey;
  72 import org.opendaylight.yangtools.yang.binding.Notification;
  73 import org.slf4j.Logger;
  74 import org.slf4j.LoggerFactory;
  75
  76 @VisibleForTesting
  77 public class BGPSessionImpl extends SimpleChannelInboundHandler<Notification> implements BGPSession, BGPSessionStats,
  78     BGPSessionStateProvider, AutoCloseable {
  79
  80     private static final Logger LOG = LoggerFactory.getLogger(BGPSessionImpl.class);
  81
  82     private static final Notification KEEP_ALIVE = new KeepaliveBuilder().build();
  83
  84     private static final int KA_TO_DEADTIMER_RATIO = 3;
  85
  86     private static final String EXTENDED_MSG_DECODER = "EXTENDED_MSG_DECODER";
  87
  88     static final String END_OF_INPUT = "End of input detected. Close the session.";
  89
  90     /**
  91      * System.nanoTime value about when was sent the last message.
  92      */
  93     @VisibleForTesting
  94     private long lastMessageSentAt;
  95
  96     /**
  97      * System.nanoTime value about when was received the last message
  98      */
  99     private long lastMessageReceivedAt;
 100
 101     private final BGPSessionListener listener;
 102
 103     private final BGPSynchronization sync;
 104
 105     private int kaCounter = 0;
 106
 107     private final Channel channel;
 108
 109     @GuardedBy("this")
 110     private State state = State.OPEN_CONFIRM;
 111
 112     private final Set<BgpTableType> tableTypes;
 113     private final List<AddressFamilies> addPathTypes;
 114     private final int holdTimerValue;
 115     private final int keepAlive;
 116     private final AsNumber asNumber;
 117     private final Ipv4Address bgpId;
 118     private final BGPPeerRegistry peerRegistry;
 119     private final ChannelOutputLimiter limiter;
 120     private final BGPSessionStateImpl sessionState;
 121
 122     private BGPSessionStatsImpl sessionStats;
 123
 124     public BGPSessionImpl(final BGPSessionListener listener, final Channel channel, final Open remoteOpen,
 125         final BGPSessionPreferences localPreferences, final BGPPeerRegistry peerRegistry) {
 126         this(listener, channel, remoteOpen, localPreferences.getHoldTime(), peerRegistry);
 127         this.sessionStats = new BGPSessionStatsImpl(this, remoteOpen, this.holdTimerValue, this.keepAlive, channel,
 128             Optional.of(localPreferences), this.tableTypes, this.addPathTypes);
 129     }
 130
 131     public BGPSessionImpl(final BGPSessionListener listener, final Channel channel, final Open remoteOpen,
 132         final int localHoldTimer, final BGPPeerRegistry peerRegistry) {
 133         this.listener = Preconditions.checkNotNull(listener);
 134         this.channel = Preconditions.checkNotNull(channel);
 135         this.limiter = new ChannelOutputLimiter(this);
 136         this.channel.pipeline().addLast(this.limiter);
 137         this.holdTimerValue = (remoteOpen.getHoldTimer() < localHoldTimer) ? remoteOpen.getHoldTimer() : localHoldTimer;
 138         LOG.info("BGP HoldTimer new value: {}", this.holdTimerValue);
 139         this.keepAlive = this.holdTimerValue / KA_TO_DEADTIMER_RATIO;
 140         this.asNumber = AsNumberUtil.advertizedAsNumber(remoteOpen);
 141         this.peerRegistry = peerRegistry;
 142         this.sessionState = new BGPSessionStateImpl();
 143
 144         final Set<TablesKey> tts = Sets.newHashSet();
 145         final Set<BgpTableType> tats = Sets.newHashSet();
 146         final List<AddressFamilies> addPathCapabilitiesList = Lists.newArrayList();
 147         if (remoteOpen.getBgpParameters() != null) {
 148             for (final BgpParameters param : remoteOpen.getBgpParameters()) {
 149                 for (final OptionalCapabilities optCapa : param.getOptionalCapabilities()) {
 150                     final CParameters cParam = optCapa.getCParameters();
 151                     if ( cParam.getAugmentation(CParameters1.class) == null) {
 152                         continue;
 153                     }
 154                     if(cParam.getAugmentation(CParameters1.class).getMultiprotocolCapability() != null) {
 155                         final MultiprotocolCapability multi = cParam.getAugmentation(CParameters1.class).getMultiprotocolCapability();
 156                         final TablesKey tt = new TablesKey(multi.getAfi(), multi.getSafi());
 157                         LOG.trace("Added table type to sync {}", tt);
 158                         tts.add(tt);
 159                         tats.add(new BgpTableTypeImpl(tt.getAfi(), tt.getSafi()));
 160                     } else if (cParam.getAugmentation(CParameters1.class).getAddPathCapability() != null) {
 161                         final AddPathCapability addPathCap = cParam.getAugmentation(CParameters1.class).getAddPathCapability();
 162                         addPathCapabilitiesList.addAll(addPathCap.getAddressFamilies());
 163                     }
 164                 }
 165             }
 166         }
 167
 168         this.sync = new BGPSynchronization(this.listener, tts);
 169         this.tableTypes = tats;
 170         this.addPathTypes = addPathCapabilitiesList;
 171
 172         if (! this.addPathTypes.isEmpty()) {
 173             final ChannelPipeline pipeline = this.channel.pipeline();
 174             final BGPByteToMessageDecoder decoder = pipeline.get(BGPByteToMessageDecoder.class);
 175             decoder.addDecoderConstraint(MultiPathSupport.class,
 176                     MultiPathSupportImpl.createParserMultiPathSupport(this.addPathTypes));
 177         }
 178
 179         if (this.holdTimerValue != 0) {
 180             channel.eventLoop().schedule(new Runnable() {
 181                 @Override
 182                 public void run() {
 183                     handleHoldTimer();
 184                 }
 185             }, this.holdTimerValue, TimeUnit.SECONDS);
 186
 187             channel.eventLoop().schedule(new Runnable() {
 188                 @Override
 189                 public void run() {
 190                     handleKeepaliveTimer();
 191                 }
 192             }, this.keepAlive, TimeUnit.SECONDS);
 193         }
 194         this.bgpId = remoteOpen.getBgpIdentifier();
 195         this.sessionStats = new BGPSessionStatsImpl(this, remoteOpen, this.holdTimerValue, this.keepAlive, channel, Optional.<BGPSessionPreferences>absent(),
 196                 this.tableTypes, this.addPathTypes);
 197
 198         this.sessionState.advertizeCapabilities(this.holdTimerValue, channel.remoteAddress(), channel.localAddress(),
 199             this.tableTypes, remoteOpen.getBgpParameters());
 200     }
 201
 202     /**
 203      * Set the extend message coder for current channel
 204      * The reason for separating this part from constructor is, in #channel.pipeline().replace(..), the
 205      * invokeChannelRead() will be invoked after the original message coder handler got removed. And there
 206      * is chance that before the session instance is fully initiated (constructor returns), a KeepAlive
 207      * message arrived already in the channel buffer. Thus #AbstractBGPSessionNegotiator.handleMessage(..)
 208      * gets invoked again and a deadlock is caused.  A BGP final state machine error will happen as BGP
 209      * negotiator is still in OPEN_SENT state as the session constructor hasn't returned yet.
 210      *
 211      * @param remoteOpen
 212      */
 213     public synchronized void setChannelExtMsgCoder(final Open remoteOpen) {
 214         final boolean enableExMess = BgpExtendedMessageUtil.advertizedBgpExtendedMessageCapability(remoteOpen);
 215         if (enableExMess) {
 216             this.channel.pipeline().replace(BGPMessageHeaderDecoder.class, EXTENDED_MSG_DECODER, BGPMessageHeaderDecoder.getExtendedBGPMessageHeaderDecoder());
 217         }
 218     }
 219
 220     @Override
 221     public synchronized void close() {
 222         if (this.state != State.IDLE) {
 223             this.writeAndFlush(new NotifyBuilder().setErrorCode(BGPError.CEASE.getCode()).setErrorSubcode(BGPError.CEASE.getSubcode()).build());
 224             this.closeWithoutMessage();
 225         }
 226     }
 227
 228     /**
 229      * Handles incoming message based on their type.
 230      *
 231      * @param msg incoming message
 232      */
 233     synchronized void handleMessage(final Notification msg) {
 234         if (this.state == State.IDLE) {
 235             return;
 236         }
 237         try {
 238             // Update last reception time
 239             this.lastMessageReceivedAt = System.nanoTime();
 240
 241             if (msg instanceof Open) {
 242                 // Open messages should not be present here
 243                 this.terminate(new BGPDocumentedException(null, BGPError.FSM_ERROR));
 244             } else if (msg instanceof Notify) {
 245                 final Notify notify = (Notify) msg;
 246                 // Notifications are handled internally
 247                 LOG.info("Session closed because Notification message received: {} / {}, data={}", notify.getErrorCode(),
 248                     notify.getErrorSubcode(), notify.getData() != null ? ByteBufUtil.hexDump(notify.getData()) : null);
 249                 this.closeWithoutMessage();
 250                 this.listener.onSessionTerminated(this, new BGPTerminationReason(
 251                     BGPError.forValue(notify.getErrorCode(), notify.getErrorSubcode())));
 252             } else if (msg instanceof Keepalive) {
 253                 // Keepalives are handled internally
 254                 LOG.trace("Received KeepAlive message.");
 255                 this.kaCounter++;
 256                 if (this.kaCounter >= 2) {
 257                     this.sync.kaReceived();
 258                 }
 259             } else if (msg instanceof RouteRefresh) {
 260                 this.listener.onMessage(this, msg);
 261             } else if (msg instanceof Update) {
 262                 this.listener.onMessage(this, msg);
 263                 this.sync.updReceived((Update) msg);
 264             } else {
 265                 LOG.warn("Ignoring unhandled message: {}.", msg.getClass());
 266             }
 267
 268             this.sessionStats.updateReceivedMsg(msg);
 269             this.sessionState.messageReceived(msg);
 270         } catch (final BGPDocumentedException e) {
 271             this.terminate(e);
 272         }
 273     }
 274
 275     synchronized void endOfInput() {
 276         if (this.state == State.UP) {
 277             LOG.info(END_OF_INPUT);
 278             this.listener.onSessionDown(this, new IOException(END_OF_INPUT));
 279         }
 280     }
 281
 282     @GuardedBy("this")
 283     private ChannelFuture writeEpilogue(final ChannelFuture future, final Notification msg) {
 284         future.addListener(
 285             new ChannelFutureListener() {
 286                 @Override
 287                 public void operationComplete(final ChannelFuture f) {
 288                     if (!f.isSuccess()) {
 289                         LOG.warn("Failed to send message {} to socket {}", msg, BGPSessionImpl.this.channel, f.cause());
 290                     } else {
 291                         LOG.trace("Message {} sent to socket {}", msg, BGPSessionImpl.this.channel);
 292                     }
 293                 }
 294             });
 295         this.lastMessageSentAt = System.nanoTime();
 296         this.sessionStats.updateSentMsg(msg);
 297         this.sessionState.messageSent(msg);
 298         return future;
 299     }
 300
 301     void flush() {
 302         this.channel.flush();
 303     }
 304
 305     synchronized void write(final Notification msg) {
 306         try {
 307             writeEpilogue(this.channel.write(msg), msg);
 308         } catch (final Exception e) {
 309             LOG.warn("Message {} was not sent.", msg, e);
 310         }
 311     }
 312
 313     synchronized ChannelFuture writeAndFlush(final Notification msg) {
 314         if (isWritable()) {
 315             return writeEpilogue(this.channel.writeAndFlush(msg), msg);
 316         }
 317         return this.channel.newFailedFuture(new NonWritableChannelException());
 318     }
 319
 320     private synchronized void closeWithoutMessage() {
 321         if (this.state == State.IDLE) {
 322             return;
 323         }
 324         LOG.info("Closing session: {}", this);
 325         this.channel.close().addListener(new ChannelFutureListener() {
 326             @Override
 327             public void operationComplete(final ChannelFuture future) throws Exception {
 328                 Preconditions.checkArgument(future.isSuccess(), "Channel failed to close: %s", future.cause());
 329             }
 330         });
 331         this.state = State.IDLE;
 332         removePeerSession();
 333         this.sessionState.setSessionState(this.state);
 334     }
 335
 336     /**
 337      * Closes BGP session from the parent with given reason. A message needs to be sent, but parent doesn't have to be
 338      * modified, because he initiated the closing. (To prevent concurrent modification exception).
 339      *
 340      * @param e BGPDocumentedException
 341      */
 342     private synchronized void terminate(final BGPDocumentedException e) {
 343         final BGPError error = e.getError();
 344         final byte[] data = e.getData();
 345         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(error.getCode()).setErrorSubcode(error.getSubcode());
 346         if (data != null && data.length != 0) {
 347             builder.setData(data);
 348         }
 349         this.writeAndFlush(builder.build());
 350         this.listener.onSessionTerminated(this, new BGPTerminationReason(error));
 351         this.closeWithoutMessage();
 352     }
 353
 354     private void removePeerSession() {
 355         if (this.peerRegistry != null) {
 356             this.peerRegistry.removePeerSession(StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress()));
 357         }
 358     }
 359
 360     /**
 361      * If HoldTimer expires, the session ends. If a message (whichever) was received during this period, the HoldTimer
 362      * will be rescheduled by HOLD_TIMER_VALUE + the time that has passed from the start of the HoldTimer to the time at
 363      * which the message was received. If the session was closed by the time this method starts to execute (the session
 364      * state will become IDLE), then rescheduling won't occur.
 365      */
 366     private synchronized void handleHoldTimer() {
 367         if (this.state == State.IDLE) {
 368             return;
 369         }
 370
 371         final long ct = System.nanoTime();
 372         final long nextHold = this.lastMessageReceivedAt + TimeUnit.SECONDS.toNanos(this.holdTimerValue);
 373
 374         if (ct >= nextHold) {
 375             LOG.debug("HoldTimer expired. {}", new Date());
 376             this.terminate(new BGPDocumentedException(BGPError.HOLD_TIMER_EXPIRED));
 377         } else {
 378             this.channel.eventLoop().schedule(new Runnable() {
 379                 @Override
 380                 public void run() {
 381                     handleHoldTimer();
 382                 }
 383             }, nextHold - ct, TimeUnit.NANOSECONDS);
 384         }
 385     }
 386
 387     /**
 388      * If KeepAlive Timer expires, sends KeepAlive message. If a message (whichever) was send during this period, the
 389      * KeepAlive Timer will be rescheduled by KEEP_ALIVE_TIMER_VALUE + the time that has passed from the start of the
 390      * KeepAlive timer to the time at which the message was sent. If the session was closed by the time this method
 391      * starts to execute (the session state will become IDLE), that rescheduling won't occur.
 392      */
 393     private synchronized void handleKeepaliveTimer() {
 394         if (this.state == State.IDLE) {
 395             return;
 396         }
 397
 398         final long ct = System.nanoTime();
 399         long nextKeepalive = this.lastMessageSentAt + TimeUnit.SECONDS.toNanos(this.keepAlive);
 400
 401         if (ct >= nextKeepalive) {
 402             this.writeAndFlush(KEEP_ALIVE);
 403             nextKeepalive = this.lastMessageSentAt + TimeUnit.SECONDS.toNanos(this.keepAlive);
 404             this.sessionStats.updateSentMsgKA();
 405         }
 406         this.channel.eventLoop().schedule(new Runnable() {
 407             @Override
 408             public void run() {
 409                 handleKeepaliveTimer();
 410             }
 411         }, nextKeepalive - ct, TimeUnit.NANOSECONDS);
 412     }
 413
 414     @Override
 415     public final String toString() {
 416         return addToStringAttributes(MoreObjects.toStringHelper(this)).toString();
 417     }
 418
 419     protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
 420         toStringHelper.add("channel", this.channel);
 421         toStringHelper.add("state", this.getState());
 422         return toStringHelper;
 423     }
 424
 425     @Override
 426     public Set<BgpTableType> getAdvertisedTableTypes() {
 427         return this.tableTypes;
 428     }
 429
 430     @Override
 431     public List<AddressFamilies> getAdvertisedAddPathTableTypes() {
 432         return this.addPathTypes;
 433     }
 434
 435     @Override
 436     public List<BgpTableType> getAdvertisedGracefulRestartTableTypes() {
 437         return Collections.emptyList();
 438     }
 439
 440     protected synchronized void sessionUp() {
 441         this.sessionStats.startSessionStopwatch();
 442         this.state = State.UP;
 443         this.sessionState.setSessionState(this.state);
 444         this.listener.onSessionUp(this);
 445     }
 446
 447     public synchronized State getState() {
 448         return this.state;
 449     }
 450
 451     @Override
 452     public final Ipv4Address getBgpId() {
 453         return this.bgpId;
 454     }
 455
 456     @Override
 457     public final AsNumber getAsNumber() {
 458         return this.asNumber;
 459     }
 460
 461     synchronized boolean isWritable() {
 462         return this.channel != null && this.channel.isWritable();
 463     }
 464
 465     @Override
 466     public synchronized BgpSessionState getBgpSessionState() {
 467         return this.sessionStats.getBgpSessionState();
 468     }
 469
 470     @Override
 471     public synchronized void resetBgpSessionStats() {
 472         this.sessionStats.resetBgpSessionStats();
 473     }
 474
 475     public ChannelOutputLimiter getLimiter() {
 476         return this.limiter;
 477     }
 478
 479     @Override
 480     public final void channelInactive(final ChannelHandlerContext ctx) {
 481         LOG.debug("Channel {} inactive.", ctx.channel());
 482         this.endOfInput();
 483
 484         try {
 485             super.channelInactive(ctx);
 486         } catch (final Exception e) {
 487             throw new IllegalStateException("Failed to delegate channel inactive event on channel " + ctx.channel(), e);
 488         }
 489     }
 490
 491     @Override
 492     protected final void channelRead0(final ChannelHandlerContext ctx, final Notification msg) {
 493         LOG.debug("Message was received: {}", msg);
 494         this.handleMessage(msg);
 495     }
 496
 497     @Override
 498     public final void handlerAdded(final ChannelHandlerContext ctx) {
 499         this.sessionUp();
 500     }
 501
 502     @Override
 503     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 504         LOG.warn("BGP session encountered error", cause);
 505         if (cause.getCause() instanceof BGPDocumentedException) {
 506             this.terminate((BGPDocumentedException) cause.getCause());
 507         } else {
 508             this.close();
 509         }
 510     }
 511
 512     @Override
 513     public BGPSessionState getBGPSessionState() {
 514         return this.sessionState;
 515     }
 516
 517     @Override
 518     public BGPTimersState getBGPTimersState() {
 519         return this.sessionState;
 520     }
 521
 522     @Override
 523     public BGPTransportState getBGPTransportState() {
 524         return this.sessionState;
 525     }
 526
 527     @Override
 528     public void registerMessagesCounter(final BGPMessagesListener bgpMessagesListener) {
 529         this.sessionState.registerMessagesCounter(bgpMessagesListener);
 530     }
 531 }