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.impl.spi.BGPSessionValidator;
  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 BGPSessionValidator sessionValidator;
  79     private final Promise<BGPSessionImpl> promise;
  80     private final Channel channel;
  81     @GuardedBy("this")
  82     private State state = State.IDLE;
  83
  84     @GuardedBy("this")
  85     private BGPSessionImpl session;
  86
  87     public AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  88             final BGPPeerRegistry registry, final BGPSessionValidator sessionValidator) {
  89         this.promise = Preconditions.checkNotNull(promise);
  90         this.channel = Preconditions.checkNotNull(channel);
  91         this.registry = registry;
  92         this.sessionValidator = sessionValidator;
  93     }
  94
  95     private synchronized void startNegotiation() {
  96         Preconditions.checkState(this.state == State.IDLE);
  97
  98         // Check if peer is configured in registry before retrieving preferences
  99         if (!this.registry.isPeerConfigured(getRemoteIp())) {
 100             final BGPDocumentedException cause = new BGPDocumentedException(
 101                     "BGP peer with ip: " + getRemoteIp()
 102                     + " not configured, check configured peers in : "
 103                     + this.registry, BGPError.CONNECTION_REJECTED);
 104             negotiationFailed(cause);
 105             return;
 106         }
 107
 108         final BGPSessionPreferences preferences = getPreferences();
 109
 110         int as = preferences.getMyAs().getValue().intValue();
 111         // Set as AS_TRANS if the value is bigger than 2B
 112         if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 113             as = AS_TRANS;
 114         }
 115         this.sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 116                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 117         if (this.state != State.FINISHED) {
 118             this.state = State.OPEN_SENT;
 119
 120             this.channel.eventLoop().schedule(new Runnable() {
 121                 @Override
 122                 public void run() {
 123                     if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 124                         AbstractBGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 125                         negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 126                         AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 127                     }
 128                 }
 129             }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 130         }
 131     }
 132
 133     private BGPSessionPreferences getPreferences() {
 134         return this.registry.getPeerPreferences(getRemoteIp());
 135     }
 136
 137     private IpAddress getRemoteIp() {
 138         return StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 139     }
 140
 141     protected synchronized void handleMessage(final Notification msg) {
 142         LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 143
 144         switch (this.state) {
 145         case FINISHED:
 146         case IDLE:
 147             this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 148             return;
 149         case OPEN_CONFIRM:
 150             if (msg instanceof Keepalive) {
 151                 negotiationSuccessful(this.session);
 152                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 153             } else if (msg instanceof Notify) {
 154                 final Notify ntf = (Notify) msg;
 155                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 156             }
 157             this.state = State.FINISHED;
 158             return;
 159         case OPEN_SENT:
 160             if (msg instanceof Open) {
 161                 final Open openObj = (Open) msg;
 162                 handleOpen(openObj);
 163                 return;
 164             }
 165             break;
 166         default:
 167             break;
 168         }
 169
 170         // Catch-all for unexpected message
 171         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 172         this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 173         negotiationFailed(new BGPDocumentedException("Unexpected message", BGPError.FSM_ERROR));
 174         this.state = State.FINISHED;
 175     }
 176
 177     private static Notify buildErrorNotify(final BGPError err) {
 178         return buildErrorNotify(err, null);
 179     }
 180
 181     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 182         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 183         if (data != null && data.length != 0) {
 184             builder.setData(data);
 185         }
 186         return builder.build();
 187     }
 188
 189     private void handleOpen(final Open openObj) {
 190         try {
 191             this.sessionValidator.validate(openObj, getPreferences());
 192         } catch (final BGPDocumentedException e) {
 193             negotiationFailed(e);
 194             return;
 195         }
 196
 197         try {
 198             final BGPSessionListener peer = this.registry.getPeer(getRemoteIp(), getSourceId(openObj, getPreferences()),
 199                     getDestinationId(openObj, getPreferences()), getAsNumber(openObj, getPreferences()));
 200             this.sendMessage(new KeepaliveBuilder().build());
 201             this.session = new BGPSessionImpl(peer, this.channel, openObj, getPreferences(), this.registry);
 202             this.state = State.OPEN_CONFIRM;
 203             LOG.debug("Channel {} moved to OpenConfirm 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 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             this.sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 216         }
 217         this.registry.removePeerSession(getRemoteIp());
 218         negotiationFailedCloseChannel(e);
 219         this.state = State.FINISHED;
 220     }
 221
 222     /**
 223      * @param openMsg Open message received from remote BGP speaker
 224      * @param preferences Local BGP speaker preferences
 225      * @return BGP Id of device that accepted the connection
 226      */
 227     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 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 getSourceId(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 AS Number of device that initiate connection
 240      */
 241     protected abstract AsNumber getAsNumber(final Open openMsg, final BGPSessionPreferences preferences);
 242
 243     public synchronized State getState() {
 244         return this.state;
 245     }
 246
 247     private void negotiationSuccessful(BGPSessionImpl session) {
 248         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 249         channel.pipeline().replace(this, "session", session);
 250         promise.setSuccess(session);
 251     }
 252
 253     private void negotiationFailedCloseChannel(Throwable cause) {
 254         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 255         channel.close();
 256         promise.setFailure(cause);
 257     }
 258
 259     private void sendMessage(final Notification msg) {
 260         channel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
 261             @Override
 262             public void operationComplete(ChannelFuture f) {
 263                 if (!f.isSuccess()) {
 264                     LOG.info("Failed to send message {}", msg, f.cause());
 265                     negotiationFailedCloseChannel(f.cause());
 266                 } else {
 267                     LOG.trace("Message {} sent to socket", msg);
 268                 }
 269
 270             }
 271         });
 272     }
 273
 274     @Override
 275     public final void channelActive(ChannelHandlerContext ctx) {
 276         LOG.debug("Starting session negotiation on channel {}", this.channel);
 277
 278         try {
 279             this.startNegotiation();
 280         } catch (final Exception e) {
 281             LOG.warn("Unexpected negotiation failure", e);
 282             negotiationFailedCloseChannel(e);
 283         }
 284
 285     }
 286
 287     @Override
 288     public final void channelRead(ChannelHandlerContext ctx, Object msg) {
 289         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 290
 291         try {
 292             handleMessage((Notification) msg);
 293         } catch (Exception e) {
 294             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 295             negotiationFailedCloseChannel(e);
 296         }
 297
 298     }
 299
 300     @Override
 301     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
 302         LOG.info("Unexpected error during negotiation", cause);
 303         negotiationFailedCloseChannel(cause);
 304     }
 305 }