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