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
  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 Promise<BGPSessionImpl> promise;
  79     private final Channel channel;
  80     @GuardedBy("this")
  81     private State state = State.IDLE;
  82     @GuardedBy("this")
  83     private BGPSessionImpl session;
  84     @GuardedBy("this")
  85     private ScheduledFuture<?> pending;
  86
  87     AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  88             final BGPPeerRegistry registry) {
  89         this.promise = requireNonNull(promise);
  90         this.channel = requireNonNull(channel);
  91         this.registry = registry;
  92     }
  93
  94     private synchronized void startNegotiation() {
  95         if (!(this.state == State.IDLE || this.state == State.OPEN_CONFIRM)) {
  96             return;
  97         }
  98         // Open can be sent first either from ODL (IDLE) or from peer (OPEN_CONFIRM)
  99         final IpAddress remoteIp = getRemoteIp();
 100         try {
 101             // Check if peer is configured in registry before retrieving preferences
 102             if (!this.registry.isPeerConfigured(remoteIp)) {
 103                 final BGPDocumentedException cause = new BGPDocumentedException(
 104                     String.format("BGP peer with ip: %s not configured, check configured peers in : %s",
 105                             remoteIp, this.registry), BGPError.CONNECTION_REJECTED);
 106                 negotiationFailed(cause);
 107                 return;
 108             }
 109
 110             final BGPSessionPreferences preferences = this.registry.getPeerPreferences(remoteIp);
 111
 112             int as = preferences.getMyAs().getValue().intValue();
 113             // Set as AS_TRANS if the value is bigger than 2B
 114             if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 115                 as = AS_TRANS;
 116             }
 117             sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 118                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 119             if (this.state != State.FINISHED) {
 120                 this.state = State.OPEN_SENT;
 121                 this.pending = this.channel.eventLoop().schedule(() -> {
 122                     synchronized (AbstractBGPSessionNegotiator.this) {
 123                         AbstractBGPSessionNegotiator.this.pending = null;
 124                         if (AbstractBGPSessionNegotiator.this.state != State.FINISHED) {
 125                             AbstractBGPSessionNegotiator.this
 126                                 .sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 127                             negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 128                             AbstractBGPSessionNegotiator.this.state = State.FINISHED;
 129                         }
 130                     }
 131                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 132             }
 133         } catch (final Exception e) {
 134             LOG.warn("Unexpected negotiation failure", e);
 135             negotiationFailedCloseChannel(e);
 136         }
 137     }
 138
 139     private IpAddress getRemoteIp() {
 140         final IpAddress remoteIp = StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 141         if (remoteIp.getIpv6Address() != null) {
 142             return new IpAddress(Ipv6Util.getFullForm(remoteIp.getIpv6Address()));
 143         }
 144         return new IpAddress(new Ipv4Address(remoteIp.getIpv4Address()));
 145     }
 146
 147     protected synchronized void handleMessage(final Notification msg) {
 148         LOG.debug("Channel {} handling message in state {}, msg: {}", this.channel, this.state, msg);
 149         switch (this.state) {
 150         case FINISHED:
 151             sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 152             return;
 153         case IDLE:
 154             // to avoid race condition when Open message was sent by the peer before startNegotiation could be 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", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 169             }
 170             this.state = State.FINISHED;
 171             return;
 172         case OPEN_SENT:
 173             if (msg instanceof Open) {
 174                 handleOpen((Open) msg);
 175                 return;
 176             }
 177             break;
 178         default:
 179             break;
 180         }
 181
 182         // Catch-all for unexpected message
 183         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 184         sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 185         negotiationFailed(new BGPDocumentedException("Unexpected message channel: " + 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), getDestinationId(openObj, preferences), openObj);
 206             sendMessage(new KeepaliveBuilder().build());
 207             this.state = State.OPEN_CONFIRM;
 208             this.session = new BGPSessionImpl(peer, this.channel, openObj, preferences, this.registry);
 209             this.session.setChannelExtMsgCoder(openObj);
 210             LOG.debug("Channel {} moved to OPEN_CONFIRM state with remote proposal {}", this.channel, openObj);
 211         } catch (final BGPDocumentedException e) {
 212             LOG.warn("Channel {} negotiation failed", this.channel, e);
 213             negotiationFailed(e);
 214         }
 215     }
 216
 217     private synchronized void negotiationFailed(final Throwable e) {
 218         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 219         if (e instanceof BGPDocumentedException) {
 220             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 221             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 222             sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError(), ((BGPDocumentedException) e).getData()));
 223         }
 224         if (this.state == State.OPEN_CONFIRM) {
 225             this.registry.removePeerSession(getRemoteIp());
 226         }
 227         negotiationFailedCloseChannel(e);
 228         this.state = State.FINISHED;
 229     }
 230
 231     /**
 232      * @param openMsg Open message received from remote BGP speaker
 233      * @param preferences Local BGP speaker preferences
 234      * @return BGP Id of device that accepted the connection
 235      */
 236     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 237
 238     /**
 239      * @param openMsg Open message received from remote BGP speaker
 240      * @param preferences Local BGP speaker preferences
 241      * @return BGP Id of device that accepted the connection
 242      */
 243     protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences);
 244
 245     public synchronized State getState() {
 246         return this.state;
 247     }
 248
 249     private void negotiationSuccessful(final BGPSessionImpl session) {
 250         LOG.debug("Negotiation on channel {} successful with session {}", this.channel, session);
 251         this.channel.pipeline().replace(this, "session", session);
 252         this.promise.setSuccess(session);
 253     }
 254
 255     private void negotiationFailedCloseChannel(final Throwable cause) {
 256         LOG.debug("Negotiation on channel {} failed", this.channel, cause);
 257         this.channel.close();
 258         synchronized (AbstractBGPSessionNegotiator.this) {
 259             if (this.pending != null && this.pending.isCancellable()) {
 260                 this.pending.cancel(true);
 261                 this.pending = null;
 262             }
 263         }
 264     }
 265
 266     private void sendMessage(final Notification msg) {
 267         this.channel.writeAndFlush(msg).addListener((ChannelFutureListener) f -> {
 268             if (!f.isSuccess()) {
 269                 LOG.warn("Failed to send message {} to channel {}", msg,  AbstractBGPSessionNegotiator.this.channel, f.cause());
 270                 negotiationFailedCloseChannel(f.cause());
 271             } else {
 272                 LOG.trace("Message {} sent to channel {}", msg, AbstractBGPSessionNegotiator.this.channel);
 273             }
 274         });
 275     }
 276
 277     @Override
 278     public final void channelActive(final ChannelHandlerContext ctx) {
 279         LOG.debug("Starting session negotiation on channel {}", this.channel);
 280         startNegotiation();
 281     }
 282
 283     @Override
 284     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 285         LOG.debug("Negotiation read invoked on channel {}", this.channel);
 286         try {
 287             handleMessage((Notification) msg);
 288         } catch (final Exception e) {
 289             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 290             negotiationFailedCloseChannel(e);
 291         }
 292
 293     }
 294
 295     @Override
 296     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 297         LOG.info("Unexpected error during negotiation", cause);
 298         negotiationFailedCloseChannel(cause);
 299     }
 300 }