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.util.concurrent.Promise;
  15 import java.util.concurrent.TimeUnit;
  16 import javax.annotation.concurrent.GuardedBy;
  17 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  18 import org.opendaylight.protocol.bgp.parser.BGPError;
  19 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPPeerRegistry;
  20 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences;
  21 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionValidator;
  22 import org.opendaylight.protocol.bgp.rib.spi.BGPSessionListener;
  23 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  24 import org.opendaylight.protocol.util.Values;
  25 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
  26 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Address;
  27 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  28 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  30 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  31 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder;
  33 import org.opendaylight.yangtools.yang.binding.Notification;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36
  37 /**
  38  * Bgp Session negotiator. Common for local -> remote and remote -> local connections.
  39  * One difference is session validation performed by injected BGPSessionValidator when OPEN message is received.
  40  */
  41 public abstract class AbstractBGPSessionNegotiator extends AbstractSessionNegotiator<Notification, BGPSessionImpl> {
  42     // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  43     protected static final int INITIAL_HOLDTIMER = 4;
  44
  45     /**
  46      * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  47      */
  48     private static final int AS_TRANS = 23456;
  49
  50     @VisibleForTesting
  51     public enum State {
  52         /**
  53          * Negotiation has not started yet.
  54          */
  55         Idle,
  56         /**
  57          * We have sent our Open message, and are waiting for the peer's Open message.
  58          */
  59         OpenSent,
  60         /**
  61          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  62          * Open message.
  63          */
  64         OpenConfirm,
  65         /**
  66          * The negotiation finished.
  67          */
  68         Finished,
  69     }
  70
  71     private static final Logger LOG = LoggerFactory.getLogger(AbstractBGPSessionNegotiator.class);
  72     private final BGPPeerRegistry registry;
  73     private final BGPSessionValidator sessionValidator;
  74
  75     @GuardedBy("this")
  76     private State state = State.Idle;
  77
  78     @GuardedBy("this")
  79     private BGPSessionImpl session;
  80
  81     public AbstractBGPSessionNegotiator(final Promise<BGPSessionImpl> promise, final Channel channel,
  82             final BGPPeerRegistry registry, final BGPSessionValidator sessionValidator) {
  83         super(promise, channel);
  84         this.registry = registry;
  85         this.sessionValidator = sessionValidator;
  86     }
  87
  88     @Override
  89     protected synchronized void startNegotiation() {
  90         Preconditions.checkState(this.state == State.Idle);
  91
  92         // Check if peer is configured in registry before retrieving preferences
  93         if (!this.registry.isPeerConfigured(getRemoteIp())) {
  94             final BGPDocumentedException cause = new BGPDocumentedException(
  95                     "BGP peer with ip: " + getRemoteIp()
  96                     + " not configured, check configured peers in : "
  97                     + this.registry, BGPError.CEASE);
  98             negotiationFailed(cause);
  99             return;
 100         }
 101
 102         final BGPSessionPreferences preferences = getPreferences();
 103
 104         int as = preferences.getMyAs().getValue().intValue();
 105         // Set as AS_TRANS if the value is bigger than 2B
 106         if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 107             as = AS_TRANS;
 108         }
 109         this.sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(preferences.getHoldTime()).setBgpIdentifier(
 110                 preferences.getBgpId()).setBgpParameters(preferences.getParams()).build());
 111         if (this.state != State.Finished) {
 112             this.state = State.OpenSent;
 113
 114             this.channel.eventLoop().schedule(new Runnable() {
 115                 @Override
 116                 public void run() {
 117                     if (AbstractBGPSessionNegotiator.this.state != State.Finished) {
 118                         AbstractBGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 119                         negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 120                         AbstractBGPSessionNegotiator.this.state = State.Finished;
 121                     }
 122                 }
 123             }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 124         }
 125     }
 126
 127     private BGPSessionPreferences getPreferences() {
 128         return this.registry.getPeerPreferences(getRemoteIp());
 129     }
 130
 131     private IpAddress getRemoteIp() {
 132         return StrictBGPPeerRegistry.getIpAddress(this.channel.remoteAddress());
 133     }
 134
 135     @Override
 136     protected synchronized void handleMessage(final Notification msg) {
 137         LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 138
 139         switch (this.state) {
 140         case Finished:
 141         case Idle:
 142             this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 143             return;
 144         case OpenConfirm:
 145             if (msg instanceof Keepalive) {
 146                 negotiationSuccessful(this.session);
 147                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 148             } else if (msg instanceof Notify) {
 149                 final Notify ntf = (Notify) msg;
 150                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 151             }
 152             this.state = State.Finished;
 153             return;
 154         case OpenSent:
 155             if (msg instanceof Open) {
 156                 final Open openObj = (Open) msg;
 157                 handleOpen(openObj);
 158                 return;
 159             }
 160             break;
 161         }
 162
 163         // Catch-all for unexpected message
 164         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 165         this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 166         negotiationFailed(new BGPDocumentedException("Unexpected message", BGPError.FSM_ERROR));
 167         this.state = State.Finished;
 168     }
 169
 170     private static Notify buildErrorNotify(final BGPError err) {
 171         return new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode()).build();
 172     }
 173
 174     private void handleOpen(final Open openObj) {
 175         try {
 176             this.sessionValidator.validate(openObj, getPreferences());
 177         } catch (final BGPDocumentedException e) {
 178             negotiationFailed(e);
 179             return;
 180         }
 181
 182         try {
 183             final BGPSessionListener peer = this.registry.getPeer(getRemoteIp(), getSourceId(openObj, getPreferences()), getDestinationId(openObj, getPreferences()));
 184             this.sendMessage(new KeepaliveBuilder().build());
 185             this.session = new BGPSessionImpl(peer, this.channel, openObj, getPreferences().getHoldTime());
 186             this.state = State.OpenConfirm;
 187             LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 188         } catch (final BGPDocumentedException e) {
 189             LOG.warn("Channel {} negotiation failed", this.channel, e);
 190             negotiationFailed(e);
 191         }
 192     }
 193
 194     @Override
 195     protected void negotiationFailed(final Throwable e) {
 196         LOG.warn("Channel {} negotiation failed: {}", this.channel, e.getMessage());
 197         if (e instanceof BGPDocumentedException) {
 198             // although sendMessage() can also result in calling this method, it won't create a cycle. In case sendMessage() fails to
 199             // deliver the message, this method gets called with different exception (definitely not with BGPDocumentedException).
 200             this.sendMessage(buildErrorNotify(((BGPDocumentedException)e).getError()));
 201         }
 202         super.negotiationFailed(e);
 203         this.state = State.Finished;
 204     }
 205
 206     /**
 207      * @return BGP Id of device that accepted the connection
 208      */
 209     protected abstract Ipv4Address getDestinationId(final Open openMsg, final BGPSessionPreferences preferences);
 210
 211     /**
 212      * @return BGP Id of device that initiated the connection
 213      */
 214     protected abstract Ipv4Address getSourceId(final Open openMsg, final BGPSessionPreferences preferences);
 215
 216     public synchronized State getState() {
 217         return this.state;
 218     }
 219 }