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.rev100924.IpAddress;
  29 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.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
  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                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 121                             AbstractBGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 122                             negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 123                             AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 124                         }
 125                     }
 126                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 127             }
 128         } catch (final Exception e) {
 129             LOG.warn("Unexpected negotiation failure", e);
 130             negotiationFailedCloseChannel(e);
 131         }
 132     }
 133
 134     private IpAddress getRemoteIp() {
 135         return StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 136     }
 137
 138     protected synchronized void handleMessage(final Notification msg) {
 139         LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 140
 141         switch (this.state) {
 142         case FINISHED:
 143             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 144             return;
 145         case IDLE:
 146             // to avoid race condition when Open message was sent by the peer before startNegotiation could be executed
 147            if (msg instanceof Open) {
 148                startNegotiation();
 149                handleOpen((Open) msg);
 150                return;
 151            }
 152             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 153             return;
 154         case OPEN_CONFIRM:
 155             if (msg instanceof Keepalive) {
 156                 negotiationSuccessful(this.session);
 157                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 158             } else if (msg instanceof Notify) {
 159                 final Notify ntf = (Notify) msg;
 160                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 161             }
 162             this.state = State.FINISHED;
 163             return;
 164         case OPEN_SENT:
 165             if (msg instanceof Open) {
 166                 handleOpen((Open) msg);
 167                 return;
 168             }
 169             break;
 170         default:
 171             break;
 172         }
 173
 174         // Catch-all for unexpected message
 175         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 176         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 177         negotiationFailed(new BGPDocumentedException("Unexpected message channel: " + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR));
 178         this.state = State.FINISHED;
 179     }
 180
 181     private static Notify buildErrorNotify(final BGPError err) {
 182         return buildErrorNotify(err, null);
 183     }
 184
 185     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 186         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 187         if (data != null && data.length != 0) {
 188             builder.setData(data);
 189         }
 190         return builder.build();
 191     }
 192
 193     private void handleOpen(final Open openObj) {
 194         final IpAddress remoteIp = getRemoteIp();
 195         final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 196         try {
 197             final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences), getDestinationId(openObj, preferences), openObj);
 198             sendMessage(new KeepaliveBuilder().build());
 199             this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry);
 200             this.state = State.OPEN_CONFIRM;
 201             LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 202         } catch (final BGPDocumentedException e) {
 203             LOG.warn("Channel {} negotiation failed", this.channel, e);
 204             negotiationFailed(e);
 205         }
 206     }
 207
 208     private void negotiationFailed(final Throwable e) {
 209         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 210         if (e instanceof BGPDocumentedException) {
 211             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 212             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 213             sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 214         }
 215         if (this.state == State.OPEN_CONFIRM) {
 216             this.registry.removePeerSession(getRemoteIp());
 217         }
 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     public synchronized State getState() {
 237         return this.state;
 238     }
 239
 240     private void negotiationSuccessful(final BGPSessionImpl session) {
 241         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 242         this.channel.pipeline().replace(this, "session", session);
 243         this.promise.setSuccess(session);
 244     }
 245
 246     private void negotiationFailedCloseChannel(final Throwable cause) {
 247         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 248         this.channel.close();
 249         this.promise.setFailure(cause);
 250     }
 251
 252     private void sendMessage(final Notification msg) {
 253         this.channel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
 254             @Override
 255             public void operationComplete(final ChannelFuture f) {
 256                 if (!f.isSuccess()) {
 257                     LOG.warn("Failed to send message {}", msg, f.cause());
 258                     negotiationFailedCloseChannel(f.cause());
 259                 } else {
 260                     LOG.trace("Message {} sent to socket", msg);
 261                 }
 262             }
 263         });
 264     }
 265
 266     @Override
 267     public final void channelActive(final ChannelHandlerContext ctx) {
 268         LOG.debug("Starting session negotiation on channel {}", this.channel);
 269         startNegotiation();
 270     }
 271
 272     @Override
 273     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 274         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 275         try {
 276             handleMessage((Notification) msg);
 277         } catch (final Exception e) {
 278             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 279             negotiationFailedCloseChannel(e);
 280         }
 281
 282     }
 283
 284     @Override
 285     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 286         LOG.info("Unexpected error during negotiation", cause);
 287         negotiationFailedCloseChannel(cause);
 288     }
 289 }