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 static java.util.Objects.requireNonNull;
  12
  13 import com.google.common.annotations.VisibleForTesting;
  14 import io.netty.channel.Channel;
  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 io.netty.util.concurrent.ScheduledFuture;
  20 import java.util.concurrent.TimeUnit;
  21 import javax.annotation.concurrent.GuardedBy;
  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.Ipv6Util;
  29 import org.opendaylight.protocol.util.Values;
  30 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddress;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv4Address;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.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 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     private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class);
  55     private final BGPPeerRegistry registry;
  56     private final Promise<BGPSessionImpl> promise;
  57     private final Channel channel;
  58     @GuardedBy("this")
  59     private State state = State.IDLE;
  60     @GuardedBy("this")
  61     private BGPSessionImpl session;
  62     @GuardedBy("this")
  63     private ScheduledFuture<?> pending;
  64
  65     @VisibleForTesting
  66     public enum State {
  67         /**
  68          * Negotiation has not started yet.
  69          */
  70         IDLE,
  71         /**
  72          * We have sent our Open message, and are waiting for the peer's Open message.
  73          */
  74         OPEN_SENT,
  75         /**
  76          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  77          * Open message.
  78          */
  79         OPEN_CONFIRM,
  80         /**
  81          * The negotiation finished.
  82          */
  83         FINISHED,
  84     }
  85
  86     AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  87             final BGPPeerRegistry registry) {
  88         this.promise = requireNonNull(promise);
  89         this.channel = requireNonNull(channel);
  90         this.registry = registry;
  91     }
  92
  93     private synchronized void startNegotiation() {
  94         if (!(this.state == State.IDLE || this.state == State.OPEN_CONFIRM)) {
  95             return;
  96         }
  97         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  98         final IpAddress remoteIp = getRemoteIp();
  99         try {
 100             // Check if peer is configured in registry before retrieving preferences
 101             if (!this.registry.isPeerConfigured(remoteIp)) {
 102                 final BGPDocumentedException cause = new BGPDocumentedException(
 103                         String.format("BGP peer with ip: %s not configured, check configured peers in : %s",
 104                                 remoteIp, this.registry), BGPError.CONNECTION_REJECTED);
 105                 negotiationFailed(cause);
 106                 return;
 107             }
 108
 109             final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 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                 this.pending = this.channel.eventLoop().schedule(() -> {
 121                     synchronized (AbstractBGPSessionNegotiator.this) {
 122                         AbstractBGPSessionNegotiator.this.pending = null;
 123                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 124                             AbstractBGPSessionNegotiator.this
 125                                     .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         } catch (final Exception e) {
 133             LOG.warn("Unexpected negotiation failure", e);
 134             negotiationFailedCloseChannel(e);
 135         }
 136     }
 137
 138     private IpAddress getRemoteIp() {
 139         final IpAddress remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 140         if (remoteIp.getIpv6Address() != null) {
 141             return new IpAddress(Ipv6Util.getFullForm(remoteIp.getIpv6Address()));
 142         }
 143         return remoteIp;
 144     }
 145
 146     synchronized void handleMessage(final Notification msg) {
 147         LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg);
 148         switch (this.state) {
 149             case FINISHED:
 150                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 151                 return;
 152             case IDLE:
 153                 // to avoid race condition when Open message was sent by the peer before startNegotiation could be
 154                 // executed
 155                 if (msg instanceof Open) {
 156                     startNegotiation();
 157                     handleOpen((Open) msg);
 158                     return;
 159                 }
 160                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 161                 break;
 162             case OPEN_CONFIRM:
 163                 if (msg instanceof Keepalive) {
 164                     negotiationSuccessful(this.session);
 165                     LOG.info("BGP Session with peer {} established successfully.", this.channel);
 166                 } else if (msg instanceof Notify) {
 167                     final Notify ntf = (Notify) msg;
 168                     negotiationFailed(new BGPDocumentedException("Peer refusal",
 169                             BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 170                 }
 171                 this.state = State.FINISHED;
 172                 return;
 173             case OPEN_SENT:
 174                 if (msg instanceof Open) {
 175                     handleOpen((Open) msg);
 176                     return;
 177                 }
 178                 break;
 179             default:
 180                 break;
 181         }
 182
 183         // Catch-all for unexpected message
 184         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 185         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 186         negotiationFailed(new BGPDocumentedException("Unexpected message channel: "
 187                 + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR));
 188         this.state = State.FINISHED;
 189     }
 190
 191     private static Notify buildErrorNotify(final BGPError err) {
 192         return buildErrorNotify(err, null);
 193     }
 194
 195     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 196         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 197         if (data != null && data.length != 0) {
 198             builder.setData(data);
 199         }
 200         return builder.build();
 201     }
 202
 203     private synchronized void handleOpen(final Open openObj) {
 204         final IpAddress remoteIp = getRemoteIp();
 205         final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 206         try {
 207             final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences),
 208                     getDestinationId(openObj, preferences), openObj);
 209             sendMessage(new KeepaliveBuilder().build());
 210             this.state = State.OPEN_CONFIRM;
 211             this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry);
 212             this.session.setChannelExtMsgCoder(openObj);
 213             LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", this.channel, openObj);
 214         } catch (final BGPDocumentedException e) {
 215             LOG.warn("Channel {} negotiation failed", this.channel, e);
 216             negotiationFailed(e);
 217         }
 218     }
 219
 220     private synchronized void negotiationFailed(final Throwable e) {
 221         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 222         if (e instanceof BGPDocumentedException) {
 223             // although sendMessage() can also result in calling this method, it won't create a cycle.
 224             // In case sendMessage() fails to deliver the message, this method gets called with different
 225             // exception (definitely not with BGPDocumentedException).
 226             sendMessage(buildErrorNotify(((BGPDocumentedException) e).getError(),
 227                     ((BGPDocumentedException) e).getData()));
 228         }
 229         if (this.state == State.OPEN_CONFIRM) {
 230             this.registry.removePeerSession(getRemoteIp());
 231         }
 232         negotiationFailedCloseChannel(e);
 233         this.state = State.FINISHED;
 234     }
 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 getDestinationId(Open openMsg, BGPSessionPreferences preferences);
 242
 243     /**
 244      * @param openMsg Open message received from remote BGP speaker
 245      * @param preferences Local BGP speaker preferences
 246      * @return BGP Id of device that accepted the connection
 247      */
 248     protected abstract Ipv4Address getSourceId(Open openMsg, BGPSessionPreferences preferences);
 249
 250     public synchronized State getState() {
 251         return this.state;
 252     }
 253
 254     private void negotiationSuccessful(final BGPSessionImpl session) {
 255         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 256         this.channel.pipeline().replace(this, "session", session);
 257         this.promise.setSuccess(session);
 258     }
 259
 260     private void negotiationFailedCloseChannel(final Throwable cause) {
 261         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 262         this.channel.close();
 263         synchronized (AbstractBGPSessionNegotiator.this) {
 264             if (this.pending != null && this.pending.isCancellable()) {
 265                 this.pending.cancel(true);
 266                 this.pending = null;
 267             }
 268         }
 269     }
 270
 271     private void sendMessage(final Notification msg) {
 272         this.channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 273             if (!f.isSuccess()) {
 274                 LOG.warn("Failed to send message {} to channel {}", msg, AbstractBGPSessionNegotiator.this.channel,
 275                         f.cause());
 276                 negotiationFailedCloseChannel(f.cause());
 277             } else {
 278                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 279             }
 280         });
 281     }
 282
 283     @Override
 284     public final void channelActive(final ChannelHandlerContext ctx) {
 285         LOG.debug("Starting session negotiation on channel {}", this.channel);
 286         startNegotiation();
 287     }
 288
 289     @Override
 290     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 291         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 292         try {
 293             handleMessage((Notification) msg);
 294         } catch (final Exception e) {
 295             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 296             negotiationFailedCloseChannel(e);
 297         }
 298
 299     }
 300
 301     @Override
 302     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 303         LOG.info("Unexpected error during negotiation", cause);
 304         negotiationFailedCloseChannel(cause);
 305     }
 306 }