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