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