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.AsNumberUtil;
  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.Values;
  29 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.AsNumber;
  30 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Address;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder;
  38 import org.opendaylight.yangtools.yang.binding.Notification;
  39 import org.slf4j.Logger;
  40 import org.slf4j.LoggerFactory;
  41
  42 /**
  43  * Bgp Session negotiator. Common for local-to-remote and remote-to-local connections.
  44  * One difference is session validation performed by injected BGPSessionValidator when OPEN message is received.
  45  */
  46 public abstract class AbstractBGPSessionNegotiator extends ChannelInboundHandlerAdapter implements SessionNegotiator {
  47     // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  48     private static final int INITIAL_HOLDTIMER = 4;
  49
  50     /**
  51      * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  52      */
  53     private static final int AS_TRANS = 23456;
  54
  55     @VisibleForTesting
  56     public enum State {
  57         /**
  58          * Negotiation has not started yet.
  59          */
  60         IDLE,
  61         /**
  62          * We have sent our Open message, and are waiting for the peer's Open message.
  63          */
  64         OPEN_SENT,
  65         /**
  66          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  67          * Open message.
  68          */
  69         OPEN_CONFIRM,
  70         /**
  71          * The negotiation finished.
  72          */
  73         FINISHED,
  74     }
  75
  76     private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class);
  77     private final BGPPeerRegistry registry;
  78     private final Promise<BGPSessionImpl> promise;
  79     private final Channel channel;
  80     @GuardedBy("this")
  81     private State state = State.IDLE;
  82
  83     @GuardedBy("this")
  84     private BGPSessionImpl session;
  85
  86     public AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  87             final BGPPeerRegistry registry) {
  88         this.promise = Preconditions.checkNotNull(promise);
  89         this.channel = Preconditions.checkNotNull(channel);
  90         this.registry = registry;
  91     }
  92
  93     private synchronized void startNegotiation() {
  94         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  95         Preconditions.checkState(this.state == State.IDLE || this.state == State.OPEN_CONFIRM);
  96
  97         // Check if peer is configured in registry before retrieving preferences
  98         if (!this.registry.isPeerConfigured(getRemoteIp())) {
  99             final BGPDocumentedException cause = new BGPDocumentedException(
 100                     "BGP peer with ip: " + getRemoteIp()
 101                     + " not configured, check configured peers in : "
 102                     + this.registry, BGPError.CONNECTION_REJECTED);
 103             negotiationFailed(cause);
 104             return;
 105         }
 106
 107         final BGPSessionPreferences preferences = getPreferences();
 108
 109         int as = preferences.getMyAs().getValue().intValue();
 110         // Set as AS_TRANS if the value is bigger than 2B
 111         if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 112             as = AS_TRANS;
 113         }
 114         sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 115                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 116         if (this.state != State.FINISHED) {
 117             this.state = State.OPEN_SENT;
 118
 119             this.channel.eventLoop().schedule(new Runnable() {
 120                 @Override
 121                 public void run() {
 122                     if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 123                         AbstractBGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 124                         negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 125                         AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 126                     }
 127                 }
 128             }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 129         }
 130     }
 131
 132     private BGPSessionPreferences getPreferences() {
 133         return this.registry.getPeerPreferences(getRemoteIp());
 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 {}", this.channel, this.state);
 142
 143         switch (this.state) {
 144         case FINISHED:
 145             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 146             return;
 147         case IDLE:
 148             // to avoid race condition when Open message was sent by the peer before startNegotiation could be executed
 149             if (msg instanceof Open) {
 150                 handleOpen((Open) msg);
 151                 return;
 152             }
 153             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 154             return;
 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", 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 void handleOpen(final Open openObj) {
 195         try {
 196             final BGPSessionListener peer = this.registry.getPeer(getRemoteIp(), getSourceId(openObj, getPreferences()), getDestinationId(openObj, getPreferences()), getAsNumber(openObj, getPreferences()), openObj);
 197             sendMessage(new KeepaliveBuilder().build());
 198             this.session = new BGPSessionImpl(peer, this.channel, openObj, getPreferences(), this.registry);
 199             this.state = State.OPEN_CONFIRM;
 200             LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 201         } catch (final BGPDocumentedException e) {
 202             LOG.warn("Channel {} negotiation failed", this.channel, e);
 203             negotiationFailed(e);
 204         }
 205     }
 206
 207     private void negotiationFailed(final Throwable e) {
 208         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 209         if (e instanceof BGPDocumentedException) {
 210             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 211             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 212             sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 213         }
 214         this.registry.removePeerSession(getRemoteIp());
 215         negotiationFailedCloseChannel(e);
 216         this.state = State.FINISHED;
 217     }
 218
 219     /**
 220      * @param openMsg Open message received from remote BGP speaker
 221      * @param preferences Local BGP speaker preferences
 222      * @return BGP Id of device that accepted the connection
 223      */
 224     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 225
 226     /**
 227      * @param openMsg Open message received from remote BGP speaker
 228      * @param preferences Local BGP speaker preferences
 229      * @return BGP Id of device that accepted the connection
 230      */
 231     protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences);
 232
 233     /**
 234      * @param openMsg Open message received from remote BGP speaker
 235      * @param preferences Local BGP speaker preferences
 236      * @return AS Number of device that initiate connection
 237      */
 238     protected AsNumber getAsNumber(final Open openMsg, final BGPSessionPreferences preferences) {
 239         return AsNumberUtil.advertizedAsNumber(openMsg);
 240     }
 241
 242     public synchronized State getState() {
 243         return this.state;
 244     }
 245
 246     private void negotiationSuccessful(final BGPSessionImpl session) {
 247         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 248         this.channel.pipeline().replace(this, "session", session);
 249         this.promise.setSuccess(session);
 250     }
 251
 252     private void negotiationFailedCloseChannel(final Throwable cause) {
 253         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 254         this.channel.close();
 255         this.promise.setFailure(cause);
 256     }
 257
 258     private void sendMessage(final Notification msg) {
 259         this.channel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
 260             @Override
 261             public void operationComplete(final ChannelFuture f) {
 262                 if (!f.isSuccess()) {
 263                     LOG.info("Failed to send message {}", msg, f.cause());
 264                     negotiationFailedCloseChannel(f.cause());
 265                 } else {
 266                     LOG.trace("Message {} sent to socket", msg);
 267                 }
 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
 277         try {
 278             startNegotiation();
 279         } catch (final Exception e) {
 280             LOG.warn("Unexpected negotiation failure", e);
 281             negotiationFailedCloseChannel(e);
 282         }
 283
 284     }
 285
 286     @Override
 287     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 288         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 289
 290         try {
 291             handleMessage((Notification) msg);
 292         } catch (final Exception e) {
 293             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 294             negotiationFailedCloseChannel(e);
 295         }
 296
 297     }
 298
 299     @Override
 300     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 301         LOG.info("Unexpected error during negotiation", cause);
 302         negotiationFailedCloseChannel(cause);
 303     }
 304 }