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 package org.opendaylight.protocol.bgp.rib.impl;
   9
  10 import static java.util.Objects.requireNonNull;
  11
  12 import com.google.common.annotations.VisibleForTesting;
  13 import io.netty.channel.Channel;
  14 import io.netty.channel.ChannelFutureListener;
  15 import io.netty.channel.ChannelHandlerContext;
  16 import io.netty.channel.ChannelInboundHandlerAdapter;
  17 import io.netty.util.concurrent.Promise;
  18 import io.netty.util.concurrent.ScheduledFuture;
  19 import java.util.concurrent.TimeUnit;
  20 import org.checkerframework.checker.lock.qual.GuardedBy;
  21 import org.checkerframework.checker.lock.qual.Holding;
  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.IpAddressNoZone;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4AddressNoZone;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.OpenBuilder;
  38 import org.opendaylight.yangtools.yang.binding.Notification;
  39 import org.opendaylight.yangtools.yang.common.Uint16;
  40 import org.slf4j.Logger;
  41 import org.slf4j.LoggerFactory;
  42
  43 /**
  44  * Bgp Session negotiator. Common for local-to-remote and remote-to-local connections.
  45  * One difference is session validation performed by injected BGPSessionValidator when OPEN message is received.
  46  */
  47 abstract class AbstractBGPSessionNegotiator extends ChannelInboundHandlerAdapter implements SessionNegotiator {
  48     // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  49     private static final int INITIAL_HOLDTIMER = 4;
  50
  51     // <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  52     @VisibleForTesting
  53     static final Uint16 AS_TRANS = Uint16.valueOf(23456).intern();
  54     private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class);
  55     private final BGPPeerRegistry registry;
  56     private final Promise<BGPSessionImpl> promise;
  57     private final Channel channel;
  58     @GuardedBy("this")
  59     private State state = State.IDLE;
  60     @GuardedBy("this")
  61     private BGPSessionImpl session;
  62     @GuardedBy("this")
  63     private ScheduledFuture<?> pending;
  64
  65     @VisibleForTesting
  66     public enum State {
  67         /**
  68          * Negotiation has not started yet.
  69          */
  70         IDLE,
  71         /**
  72          * We have sent our Open message, and are waiting for the peer's Open message.
  73          */
  74         OPEN_SENT,
  75         /**
  76          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  77          * Open message.
  78          */
  79         OPEN_CONFIRM,
  80         /**
  81          * The negotiation finished.
  82          */
  83         FINISHED,
  84     }
  85
  86     AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  87             final BGPPeerRegistry registry) {
  88         this.promise = requireNonNull(promise);
  89         this.channel = requireNonNull(channel);
  90         this.registry = registry;
  91     }
  92
  93     @SuppressWarnings("checkstyle:illegalCatch")
  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 IpAddressNoZone 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",
 105                                 remoteIp, this.registry), BGPError.CONNECTION_REJECTED);
 106                 negotiationFailed(cause);
 107                 return;
 108             }
 109
 110             final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 111             final Uint16 as = openASNumber(preferences.getMyAs().getValue().longValue());
 112             sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 113                     preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 114             if (this.state != State.FINISHED) {
 115                 this.state = State.OPEN_SENT;
 116                 this.pending = this.channel.eventLoop().schedule(() -> {
 117                     synchronized (AbstractBGPSessionNegotiator.this) {
 118                         AbstractBGPSessionNegotiator.this.pending = null;
 119                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 120                             AbstractBGPSessionNegotiator.this
 121                                     .sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 122                             negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 123                             AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 124                         }
 125                     }
 126                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 127             }
 128         } catch (final Exception e) {
 129             LOG.warn("Unexpected negotiation failure", e);
 130             negotiationFailedCloseChannel(e);
 131         }
 132     }
 133
 134     private IpAddressNoZone getRemoteIp() {
 135         final IpAddressNoZone remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 136         if (remoteIp.getIpv6AddressNoZone() != null) {
 137             return new IpAddressNoZone(Ipv6Util.getFullForm(remoteIp.getIpv6AddressNoZone()));
 138         }
 139         return remoteIp;
 140     }
 141
 142     synchronized void handleMessage(final Notification msg) {
 143         LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg);
 144         switch (this.state) {
 145             case FINISHED:
 146                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 147                 return;
 148             case IDLE:
 149                 // to avoid race condition when Open message was sent by the peer before startNegotiation could be
 150                 // executed
 151                 if (msg instanceof Open) {
 152                     startNegotiation();
 153                     handleOpen((Open) msg);
 154                     return;
 155                 }
 156                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 157                 break;
 158             case OPEN_CONFIRM:
 159                 if (msg instanceof Keepalive) {
 160                     negotiationSuccessful();
 161                     LOG.info("BGP Session with peer {} established successfully.", this.channel);
 162                 } else if (msg instanceof Notify) {
 163                     final Notify ntf = (Notify) msg;
 164                     negotiationFailed(new BGPDocumentedException("Peer refusal",
 165                             BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 166                 }
 167                 this.state = State.FINISHED;
 168                 return;
 169             case OPEN_SENT:
 170                 if (msg instanceof Open) {
 171                     handleOpen((Open) msg);
 172                     return;
 173                 }
 174                 break;
 175             default:
 176                 break;
 177         }
 178
 179         // Catch-all for unexpected message
 180         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 181         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 182         negotiationFailed(new BGPDocumentedException("Unexpected message channel: "
 183                 + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR));
 184         this.state = State.FINISHED;
 185     }
 186
 187     private static Notify buildErrorNotify(final BGPError err) {
 188         return buildErrorNotify(err, null);
 189     }
 190
 191     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 192         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 193         if (data != null && data.length != 0) {
 194             builder.setData(data);
 195         }
 196         return builder.build();
 197     }
 198
 199     private synchronized void handleOpen(final Open openObj) {
 200         final IpAddressNoZone remoteIp = getRemoteIp();
 201         final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 202         try {
 203             final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences),
 204                     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 cause) {
 217         LOG.warn("Channel {} negotiation failed: {}", this.channel, cause.getMessage());
 218         if (cause instanceof BGPDocumentedException) {
 219             // although sendMessage() can also result in calling this method, it won't create a cycle.
 220             // In case sendMessage() fails to deliver the message, this method gets called with different
 221             // exception (definitely not with BGPDocumentedException).
 222             sendMessage(buildErrorNotify(((BGPDocumentedException) cause).getError(),
 223                     ((BGPDocumentedException) cause).getData()));
 224         }
 225         if (this.state == State.OPEN_CONFIRM) {
 226             this.registry.removePeerSession(getRemoteIp());
 227         }
 228         negotiationFailedCloseChannel(cause);
 229         this.state = State.FINISHED;
 230     }
 231
 232     /**
 233      * Get destination identifier.
 234      *
 235      * @param openMsg Open message received from remote BGP speaker
 236      * @param preferences Local BGP speaker preferences
 237      * @return BGP Id of device that accepted the connection
 238      */
 239     protected abstract Ipv4AddressNoZone getDestinationId(Open openMsg, BGPSessionPreferences preferences);
 240
 241     /**
 242      * Get source identifier.
 243      *
 244      * @param openMsg Open message received from remote BGP speaker
 245      * @param preferences Local BGP speaker preferences
 246      * @return BGP Id of device that accepted the connection
 247      */
 248     protected abstract Ipv4AddressNoZone getSourceId(Open openMsg, BGPSessionPreferences preferences);
 249
 250     public synchronized State getState() {
 251         return this.state;
 252     }
 253
 254     @Holding("this")
 255     private void negotiationSuccessful() {
 256         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 257         this.channel.pipeline().replace(this, "session", session);
 258         this.promise.setSuccess(session);
 259     }
 260
 261     private void negotiationFailedCloseChannel(final Throwable cause) {
 262         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 263         this.channel.close();
 264         synchronized (AbstractBGPSessionNegotiator.this) {
 265             if (this.pending != null && this.pending.isCancellable()) {
 266                 this.pending.cancel(true);
 267                 this.pending = null;
 268             }
 269         }
 270     }
 271
 272     private void sendMessage(final Notification msg) {
 273         this.channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 274             if (!f.isSuccess()) {
 275                 LOG.warn("Failed to send message {} to channel {}", msg, AbstractBGPSessionNegotiator.this.channel,
 276                         f.cause());
 277                 negotiationFailedCloseChannel(f.cause());
 278             } else {
 279                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 280             }
 281         });
 282     }
 283
 284     @Override
 285     public final void channelActive(final ChannelHandlerContext ctx) {
 286         LOG.debug("Starting session negotiation on channel {}", this.channel);
 287         startNegotiation();
 288     }
 289
 290     @Override
 291     @SuppressWarnings("checkstyle:illegalCatch")
 292     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 293         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 294         try {
 295             handleMessage((Notification) msg);
 296         } catch (final Exception e) {
 297             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 298             negotiationFailedCloseChannel(e);
 299         }
 300
 301     }
 302
 303     @Override
 304     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 305         LOG.info("Unexpected error during negotiation", cause);
 306         negotiationFailedCloseChannel(cause);
 307     }
 308
 309     @VisibleForTesting
 310     static Uint16 openASNumber(final long configuredASNumber) {
 311         // Return AS_TRANS if the value is bigger than 2B.
 312         return configuredASNumber > Values.UNSIGNED_SHORT_MAX_VALUE ? AS_TRANS : Uint16.valueOf(configuredASNumber);
 313     }
 314 }