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     @VisibleForTesting
  65     public enum State {
  66         /**
  67          * Negotiation has not started yet.
  68          */
  69         IDLE,
  70         /**
  71          * We have sent our Open message, and are waiting for the peer's Open message.
  72          */
  73         OPEN_SENT,
  74         /**
  75          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  76          * Open message.
  77          */
  78         OPEN_CONFIRM,
  79         /**
  80          * The negotiation finished.
  81          */
  82         FINISHED,
  83     }
  84
  85     AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  86             final BGPPeerRegistry registry) {
  87         this.promise = requireNonNull(promise);
  88         this.channel = requireNonNull(channel);
  89         this.registry = registry;
  90     }
  91
  92     private synchronized void startNegotiation() {
  93         if (!(this.state == State.IDLE || this.state == State.OPEN_CONFIRM)) {
  94             return;
  95         }
  96         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  97         final IpAddress remoteIp = getRemoteIp();
  98         try {
  99             // Check if peer is configured in registry before retrieving preferences
 100             if (!this.registry.isPeerConfigured(remoteIp)) {
 101                 final BGPDocumentedException cause = new BGPDocumentedException(
 102                         String.format("BGP peer with ip: %s not configured, check configured peers in : %s",
 103                                 remoteIp, this.registry), BGPError.CONNECTION_REJECTED);
 104                 negotiationFailed(cause);
 105                 return;
 106             }
 107
 108             final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 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             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                 this.pending = this.channel.eventLoop().schedule(() -> {
 120                     synchronized (AbstractBGPSessionNegotiator.this) {
 121                         AbstractBGPSessionNegotiator.this.pending = null;
 122                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 123                             AbstractBGPSessionNegotiator.this
 124                                     .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         } catch (final Exception e) {
 132             LOG.warn("Unexpected negotiation failure", e);
 133             negotiationFailedCloseChannel(e);
 134         }
 135     }
 136
 137     private IpAddress getRemoteIp() {
 138         final IpAddress remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 139         if (remoteIp.getIpv6Address() != null) {
 140             return new IpAddress(Ipv6Util.getFullForm(remoteIp.getIpv6Address()));
 141         }
 142         return remoteIp;
 143     }
 144
 145     synchronized void handleMessage(final Notification msg) {
 146         LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg);
 147         switch (this.state) {
 148             case FINISHED:
 149                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 150                 return;
 151             case IDLE:
 152                 // to avoid race condition when Open message was sent by the peer before startNegotiation could be executed
 153                 if (msg instanceof Open) {
 154                     startNegotiation();
 155                     handleOpen((Open) msg);
 156                     return;
 157                 }
 158                 sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 159                 break;
 160             case OPEN_CONFIRM:
 161                 if (msg instanceof Keepalive) {
 162                     negotiationSuccessful(this.session);
 163                     LOG.info("BGP Session with peer {} established successfully.", this.channel);
 164                 } else if (msg instanceof Notify) {
 165                     final Notify ntf = (Notify) msg;
 166                     negotiationFailed(new BGPDocumentedException("Peer refusal",
 167                             BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 168                 }
 169                 this.state = State.FINISHED;
 170                 return;
 171             case OPEN_SENT:
 172                 if (msg instanceof Open) {
 173                     handleOpen((Open) msg);
 174                     return;
 175                 }
 176                 break;
 177             default:
 178                 break;
 179         }
 180
 181         // Catch-all for unexpected message
 182         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 183         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 184         negotiationFailed(new BGPDocumentedException("Unexpected message channel: "
 185                 + this.channel + ", state: " + this.state + ", message: " + msg, BGPError.FSM_ERROR));
 186         this.state = State.FINISHED;
 187     }
 188
 189     private static Notify buildErrorNotify(final BGPError err) {
 190         return buildErrorNotify(err, null);
 191     }
 192
 193     private static Notify buildErrorNotify(final BGPError err, final byte[] data) {
 194         final NotifyBuilder builder = new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode());
 195         if (data != null && data.length != 0) {
 196             builder.setData(data);
 197         }
 198         return builder.build();
 199     }
 200
 201     private synchronized void handleOpen(final Open openObj) {
 202         final IpAddress remoteIp = getRemoteIp();
 203         final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 204         try {
 205             final BGPSessionListener peer = this.registry.getPeer(remoteIp, getSourceId(openObj, preferences),
 206                     getDestinationId(openObj, preferences), openObj);
 207             sendMessage(new KeepaliveBuilder().build());
 208             this.state = State.OPEN_CONFIRM;
 209             this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry);
 210             this.session.setChannelExtMsgCoder(openObj);
 211             LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", this.channel, openObj);
 212         } catch (final BGPDocumentedException e) {
 213             LOG.warn("Channel {} negotiation failed", this.channel, e);
 214             negotiationFailed(e);
 215         }
 216     }
 217
 218     private synchronized void negotiationFailed(final Throwable e) {
 219         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 220         if (e instanceof BGPDocumentedException) {
 221             // although sendMessage() can also result in calling this method, it won't create a cycle.
 222             // In case sendMessage() fails to deliver the message, this method gets called with different
 223             // exception (definitely not with BGPDocumentedException).
 224             sendMessage(buildErrorNotify(((BGPDocumentedException) e).getError(),
 225                     ((BGPDocumentedException) e).getData()));
 226         }
 227         if (this.state == State.OPEN_CONFIRM) {
 228             this.registry.removePeerSession(getRemoteIp());
 229         }
 230         negotiationFailedCloseChannel(e);
 231         this.state = State.FINISHED;
 232     }
 233
 234     /**
 235      * @param openMsg Open message received from remote BGP speaker
 236      * @param preferences Local BGP speaker preferences
 237      * @return BGP Id of device that accepted the connection
 238      */
 239     protected abstract Ipv4Address getDestinationId(Open openMsg, BGPSessionPreferences preferences);
 240
 241     /**
 242      * @param openMsg Open message received from remote BGP speaker
 243      * @param preferences Local BGP speaker preferences
 244      * @return BGP Id of device that accepted the connection
 245      */
 246     protected abstract Ipv4Address getSourceId(Open openMsg, BGPSessionPreferences preferences);
 247
 248     public synchronized State getState() {
 249         return this.state;
 250     }
 251
 252     private void negotiationSuccessful(final BGPSessionImpl session) {
 253         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 254         this.channel.pipeline().replace(this, "session", session);
 255         this.promise.setSuccess(session);
 256     }
 257
 258     private void negotiationFailedCloseChannel(final Throwable cause) {
 259         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 260         this.channel.close();
 261         synchronized (AbstractBGPSessionNegotiator.this) {
 262             if (this.pending != null && this.pending.isCancellable()) {
 263                 this.pending.cancel(true);
 264                 this.pending = null;
 265             }
 266         }
 267     }
 268
 269     private void sendMessage(final Notification msg) {
 270         this.channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 271             if (!f.isSuccess()) {
 272                 LOG.warn("Failed to send message {} to channel {}", msg, AbstractBGPSessionNegotiator.this.channel,
 273                         f.cause());
 274                 negotiationFailedCloseChannel(f.cause());
 275             } else {
 276                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 277             }
 278         });
 279     }
 280
 281     @Override
 282     public final void channelActive(final ChannelHandlerContext ctx) {
 283         LOG.debug("Starting session negotiation on channel {}", this.channel);
 284         startNegotiation();
 285     }
 286
 287     @Override
 288     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 289         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 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 }