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.rev200120.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev200120.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev200120.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev200120.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev200120.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev200120.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         LOG.debug("Starting negotiating with {}, current state: {}", channel.remoteAddress(), state);
  96         if (state != State.IDLE && state != State.OPEN_CONFIRM) {
  97             return;
  98         }
  99         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
 100         final IpAddressNoZone remoteIp = getRemoteIp();
 101         try {
 102             // Check if peer is configured in registry before retrieving preferences
 103             if (!registry.isPeerConfigured(remoteIp)) {
 104                 final BGPDocumentedException cause = new BGPDocumentedException(
 105                         String.format("BGP peer with ip: %s not configured, check configured peers in : %s",
 106                                 remoteIp, registry), BGPError.CONNECTION_REJECTED);
 107                 negotiationFailed(cause);
 108                 return;
 109             }
 110
 111             final BGPSessionPreferences preferences = registry.getPeerPreferences(remoteIp);
 112             final Uint16 as = openASNumber(preferences.getMyAs().getValue().longValue());
 113             sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(Uint16.valueOf(preferences.getHoldTime()))
 114                 .setBgpIdentifier(preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 115             if (state != State.FINISHED) {
 116                 state = State.OPEN_SENT;
 117                 pending = channel.eventLoop().schedule(() -> {
 118                     synchronized (AbstractBGPSessionNegotiator.this) {
 119                         AbstractBGPSessionNegotiator.this.pending = null;
 120                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 121                             AbstractBGPSessionNegotiator.this
 122                                     .sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 123                             negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 124                             AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 125                         }
 126                     }
 127                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 128             }
 129         } catch (final Exception e) {
 130             LOG.warn("Unexpected negotiation failure", e);
 131             negotiationFailedCloseChannel(e);
 132         }
 133     }
 134
 135     private IpAddressNoZone getRemoteIp() {
 136         final IpAddressNoZone remoteIp = StrictBGPPeerRegistry.getIpAddress(channel.remoteAddress());
 137         if (remoteIp.getIpv6AddressNoZone() != null) {
 138             return new IpAddressNoZone(Ipv6Util.getFullForm(remoteIp.getIpv6AddressNoZone()));
 139         }
 140         return remoteIp;
 141     }
 142
 143     synchronized void handleMessage(final Notification<?> msg) {
 144         LOG.debug("Channel {} handling message in state {}, msg: {}", channel, state, msg);
 145         switch (state) {
 146             case FINISHED:
 147                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 148                 return;
 149             case IDLE:
 150                 // to avoid race condition when Open message was sent by the peer before startNegotiation could be
 151                 // executed
 152                 if (msg instanceof Open) {
 153                     startNegotiation();
 154                     handleOpen((Open) msg);
 155                     return;
 156                 }
 157                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 158                 break;
 159             case OPEN_CONFIRM:
 160                 if (msg instanceof Keepalive) {
 161                     negotiationSuccessful();
 162                     LOG.info("BGP Session with peer {} established successfully.", channel);
 163                 } else if (msg instanceof Notify) {
 164                     final Notify ntf = (Notify) msg;
 165                     negotiationFailed(new BGPDocumentedException("Peer refusal",
 166                             BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 167                 }
 168                 state = State.FINISHED;
 169                 return;
 170             case OPEN_SENT:
 171                 if (msg instanceof Open) {
 172                     handleOpen((Open) msg);
 173                     return;
 174                 }
 175                 break;
 176             default:
 177                 break;
 178         }
 179
 180         // Catch-all for unexpected message
 181         LOG.warn("Channel {} state {} unexpected message {}", channel, state, msg);
 182         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 183         negotiationFailed(new BGPDocumentedException("Unexpected message channel: "
 184                 + channel + ", state: " + state + ", message: " + msg, BGPError.FSM_ERROR));
 185         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     @SuppressWarnings("checkstyle:illegalCatch")
 201     private synchronized void handleOpen(final Open openObj) {
 202         final IpAddressNoZone remoteIp = getRemoteIp();
 203         final BGPSessionPreferences preferences = registry.getPeerPreferences(remoteIp);
 204         try {
 205             final BGPSessionListener peer = registry.getPeer(remoteIp, getSourceId(openObj, preferences),
 206                     getDestinationId(openObj, preferences), openObj);
 207             sendMessage(new KeepaliveBuilder().build());
 208             state = State.OPEN_CONFIRM;
 209             session = new BGPSessionImpl(peer, channel, openObj, preferences, registry);
 210             session.setChannelExtMsgCoder(openObj);
 211             LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", channel, openObj);
 212         } catch (final BGPDocumentedException | RuntimeException e) {
 213             LOG.warn("Channel {} negotiation failed", channel, e);
 214             negotiationFailed(e);
 215         }
 216     }
 217
 218     private synchronized void negotiationFailed(final Throwable cause) {
 219         LOG.warn("Channel {} negotiation failed: {}", channel, cause.getMessage());
 220         if (cause instanceof BGPDocumentedException) {
 221             // although sendMessage() can also result in calling this method, it won't create a cycle.
 222             // In case sendMessage() fails to deliver the message, this method gets called with different
 223             // exception (definitely not with BGPDocumentedException).
 224             sendMessage(buildErrorNotify(((BGPDocumentedException) cause).getError(),
 225                     ((BGPDocumentedException) cause).getData()));
 226         }
 227         if (state == State.OPEN_CONFIRM) {
 228             registry.removePeerSession(getRemoteIp());
 229         }
 230         negotiationFailedCloseChannel(cause);
 231         state = State.FINISHED;
 232     }
 233
 234     /**
 235      * Get destination identifier.
 236      *
 237      * @param openMsg Open message received from remote BGP speaker
 238      * @param preferences Local BGP speaker preferences
 239      * @return BGP Id of device that accepted the connection
 240      */
 241     protected abstract Ipv4AddressNoZone getDestinationId(Open openMsg, BGPSessionPreferences preferences);
 242
 243     /**
 244      * Get source identifier.
 245      *
 246      * @param openMsg Open message received from remote BGP speaker
 247      * @param preferences Local BGP speaker preferences
 248      * @return BGP Id of device that accepted the connection
 249      */
 250     protected abstract Ipv4AddressNoZone getSourceId(Open openMsg, BGPSessionPreferences preferences);
 251
 252     public synchronized State getState() {
 253         return state;
 254     }
 255
 256     @Holding("this")
 257     private void negotiationSuccessful() {
 258         LOG.debug("Negotiation on channel {} successful with session {}", channel, session);
 259         channel.pipeline().replace(this, "session", session);
 260         promise.setSuccess(session);
 261     }
 262
 263     private void negotiationFailedCloseChannel(final Throwable cause) {
 264         LOG.debug("Negotiation on channel {} failed", channel, cause);
 265         channel.close();
 266         synchronized (AbstractBGPSessionNegotiator.this) {
 267             if (pending != null && pending.isCancellable()) {
 268                 pending.cancel(true);
 269                 pending = null;
 270             }
 271         }
 272     }
 273
 274     private void sendMessage(final Notification<?> msg) {
 275         channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 276             if (!f.isSuccess()) {
 277                 LOG.warn("Failed to send message {} to channel {}", msg, AbstractBGPSessionNegotiator.this.channel,
 278                         f.cause());
 279                 negotiationFailedCloseChannel(f.cause());
 280             } else {
 281                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 282             }
 283         });
 284     }
 285
 286     @Override
 287     public final void channelActive(final ChannelHandlerContext ctx) {
 288         LOG.debug("Starting session negotiation on channel {}", channel);
 289         startNegotiation();
 290     }
 291
 292     @Override
 293     @SuppressWarnings("checkstyle:illegalCatch")
 294     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 295         LOG.debug("Negotiation read invoked on channel {}", channel);
 296         try {
 297             handleMessage((Notification<?>) msg);
 298         } catch (final Exception e) {
 299             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 300             negotiationFailedCloseChannel(e);
 301         }
 302
 303     }
 304
 305     @Override
 306     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 307         LOG.info("Unexpected error during negotiation", cause);
 308         negotiationFailedCloseChannel(cause);
 309     }
 310
 311     @VisibleForTesting
 312     static Uint16 openASNumber(final long configuredASNumber) {
 313         // Return AS_TRANS if the value is bigger than 2B.
 314         return configuredASNumber > Values.UNSIGNED_SHORT_MAX_VALUE ? AS_TRANS : Uint16.valueOf(configuredASNumber);
 315     }
 316 }