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         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  97         Preconditions.checkState(this.state == State.IDLE || this.state == State.OPEN_CONFIRM);
  98
  99         // Check if peer is configured in registry before retrieving preferences
 100         if (!this.registry.isPeerConfigured(getRemoteIp())) {
 101             final BGPDocumentedException cause = new BGPDocumentedException(
 102                     "BGP peer with ip: " + getRemoteIp()
 103                     + " not configured, check configured peers in : "
 104                     + this.registry, BGPError.CONNECTION_REJECTED);
 105             negotiationFailed(cause);
 106             return;
 107         }
 108
 109         final BGPSessionPreferences preferences = getPreferences();
 110
 111         int as = preferences.getMyAs().getValue().intValue();
 112         // Set as AS_TRANS if the value is bigger than 2B
 113         if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 114             as = AS_TRANS;
 115         }
 116         sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 117                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 118         if (this.state != State.FINISHED) {
 119             this.state = State.OPEN_SENT;
 120
 121             this.channel.eventLoop().schedule(new Runnable() {
 122                 @Override
 123                 public void run() {
 124                     if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 125                         AbstractBGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 126                         negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 127                         AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 128                     }
 129                 }
 130             }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 131         }
 132     }
 133
 134     private BGPSessionPreferences getPreferences() {
 135         return this.registry.getPeerPreferences(getRemoteIp());
 136     }
 137
 138     private IpAddress getRemoteIp() {
 139         return StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 140     }
 141
 142     protected synchronized void handleMessage(final Notification msg) {
 143         LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 144
 145         switch (this.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 executed
 151             if (msg instanceof Open) {
 152                 handleOpen((Open) msg);
 153                 return;
 154             }
 155             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 156             return;
 157         case OPEN_CONFIRM:
 158             if (msg instanceof Keepalive) {
 159                 negotiationSuccessful(this.session);
 160                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 161             } else if (msg instanceof Notify) {
 162                 final Notify ntf = (Notify) msg;
 163                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 164             }
 165             this.state = State.FINISHED;
 166             return;
 167         case OPEN_SENT:
 168             if (msg instanceof Open) {
 169                 handleOpen((Open) msg);
 170                 return;
 171             }
 172             break;
 173         default:
 174             break;
 175         }
 176
 177         // Catch-all for unexpected message
 178         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 179         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 180         negotiationFailed(new BGPDocumentedException("Unexpected message", BGPError.FSM_ERROR));
 181         this.state = State.FINISHED;
 182     }
 183
 184     private static Notify buildErrorNotify(final BGPError err) {
 185         return buildErrorNotify(err, null);
 186     }
 187
 188     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 189         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 190         if (data != null && data.length != 0) {
 191             builder.setData(data);
 192         }
 193         return builder.build();
 194     }
 195
 196     private void handleOpen(final Open openObj) {
 197         try {
 198             this.sessionValidator.validate(openObj, getPreferences());
 199         } catch (final BGPDocumentedException e) {
 200             negotiationFailed(e);
 201             return;
 202         }
 203
 204         try {
 205             final BGPSessionListener peer = this.registry.getPeer(getRemoteIp(), getSourceId(openObj, getPreferences()), getDestinationId(openObj, getPreferences()), getAsNumber(openObj, getPreferences()), openObj);
 206             sendMessage(new KeepaliveBuilder().build());
 207             this.session = new BGPSessionImpl(peer, this.channel, openObj, getPreferences(), this.registry);
 208             this.state = State.OPEN_CONFIRM;
 209             LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 210         } catch (final BGPDocumentedException e) {
 211             LOG.warn("Channel {} negotiation failed", this.channel, e);
 212             negotiationFailed(e);
 213         }
 214     }
 215
 216     private void negotiationFailed(final Throwable e) {
 217         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 218         if (e instanceof BGPDocumentedException) {
 219             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 220             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 221             sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 222         }
 223         this.registry.removePeerSession(getRemoteIp());
 224         negotiationFailedCloseChannel(e);
 225         this.state = State.FINISHED;
 226     }
 227
 228     /**
 229      * @param openMsg Open message received from remote BGP speaker
 230      * @param preferences Local BGP speaker preferences
 231      * @return BGP Id of device that accepted the connection
 232      */
 233     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 234
 235     /**
 236      * @param openMsg Open message received from remote BGP speaker
 237      * @param preferences Local BGP speaker preferences
 238      * @return BGP Id of device that accepted the connection
 239      */
 240     protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences);
 241
 242     /**
 243      * @param openMsg Open message received from remote BGP speaker
 244      * @param preferences Local BGP speaker preferences
 245      * @return AS Number of device that initiate connection
 246      */
 247     protected abstract AsNumber getAsNumber(final Open openMsg, final BGPSessionPreferences preferences);
 248
 249     public synchronized State getState() {
 250         return this.state;
 251     }
 252
 253     private void negotiationSuccessful(final BGPSessionImpl session) {
 254         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 255         this.channel.pipeline().replace(this, "session", session);
 256         this.promise.setSuccess(session);
 257     }
 258
 259     private void negotiationFailedCloseChannel(final Throwable cause) {
 260         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 261         this.channel.close();
 262         this.promise.setFailure(cause);
 263     }
 264
 265     private void sendMessage(final Notification msg) {
 266         this.channel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
 267             @Override
 268             public void operationComplete(final ChannelFuture f) {
 269                 if (!f.isSuccess()) {
 270                     LOG.info("Failed to send message {}", msg, f.cause());
 271                     negotiationFailedCloseChannel(f.cause());
 272                 } else {
 273                     LOG.trace("Message {} sent to socket", msg);
 274                 }
 275
 276             }
 277         });
 278     }
 279
 280     @Override
 281     public final void channelActive(final ChannelHandlerContext ctx) {
 282         LOG.debug("Starting session negotiation on channel {}", this.channel);
 283
 284         try {
 285             startNegotiation();
 286         } catch (final Exception e) {
 287             LOG.warn("Unexpected negotiation failure", e);
 288             negotiationFailedCloseChannel(e);
 289         }
 290
 291     }
 292
 293     @Override
 294     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 295         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 296
 297         try {
 298             handleMessage((Notification) msg);
 299         } catch (final Exception e) {
 300             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 301             negotiationFailedCloseChannel(e);
 302         }
 303
 304     }
 305
 306     @Override
 307     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 308         LOG.info("Unexpected error during negotiation", cause);
 309         negotiationFailedCloseChannel(cause);
 310     }
 311 }