bgp/rib-impl/src/main/java/org/opendaylight/protocol/bgp/rib/impl/BGPSessionNegotiator.java

   1 /*
   2  * Copyright (c) 2013 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 package org.opendaylight.protocol.bgp.rib.impl;
   9
  10 import io.netty.channel.Channel;
  11 import io.netty.util.Timeout;
  12 import io.netty.util.Timer;
  13 import io.netty.util.TimerTask;
  14 import io.netty.util.concurrent.Promise;
  15
  16 import java.util.List;
  17 import java.util.concurrent.TimeUnit;
  18
  19 import javax.annotation.concurrent.GuardedBy;
  20
  21 import org.opendaylight.protocol.bgp.parser.AsNumberUtil;
  22 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  23 import org.opendaylight.protocol.bgp.parser.BGPError;
  24 import org.opendaylight.protocol.bgp.parser.BGPSessionListener;
  25 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences;
  26 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  27 import org.opendaylight.protocol.util.Values;
  28 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.AsNumber;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  30 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  31 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.open.BgpParameters;
  36 import org.opendaylight.yangtools.yang.binding.Notification;
  37 import org.slf4j.Logger;
  38 import org.slf4j.LoggerFactory;
  39
  40 import com.google.common.annotations.VisibleForTesting;
  41 import com.google.common.base.Preconditions;
  42
  43 public final class BGPSessionNegotiator extends AbstractSessionNegotiator<Notification, BGPSessionImpl> {
  44         // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  45         protected static final int INITIAL_HOLDTIMER = 4;
  46
  47         /**
  48          * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  49          */
  50         private static final int AS_TRANS = 23456;
  51
  52         @VisibleForTesting
  53         public enum State {
  54                 /**
  55                  * Negotiation has not started yet.
  56                  */
  57                 Idle,
  58                 /**
  59                  * We have sent our Open message, and are waiting for the peer's Open message.
  60                  */
  61                 OpenSent,
  62                 /**
  63                  * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  64                  * Open message.
  65                  */
  66                 OpenConfirm,
  67                 /**
  68                  * The negotiation finished.
  69                  */
  70                 Finished,
  71         }
  72
  73         private static final Logger LOG = LoggerFactory.getLogger(BGPSessionNegotiator.class);
  74         private final BGPSessionPreferences localPref;
  75         private final BGPSessionListener listener;
  76         private final AsNumber remoteAs;
  77         private final Timer timer;
  78
  79         @GuardedBy("this")
  80         private State state = State.Idle;
  81
  82         @GuardedBy("this")
  83         private BGPSessionImpl session;
  84
  85         public BGPSessionNegotiator(final Timer timer, final Promise<BGPSessionImpl> promise, final Channel channel,
  86                         final BGPSessionPreferences initialPrefs, final AsNumber remoteAs, final BGPSessionListener listener) {
  87                 super(promise, channel);
  88                 this.listener = Preconditions.checkNotNull(listener);
  89                 this.localPref = Preconditions.checkNotNull(initialPrefs);
  90                 this.remoteAs = Preconditions.checkNotNull(remoteAs);
  91                 this.timer = Preconditions.checkNotNull(timer);
  92         }
  93
  94         @Override
  95         protected void startNegotiation() {
  96                 Preconditions.checkState(this.state == State.Idle);
  97                 int as = this.localPref.getMyAs().getValue().intValue();
  98                 // Set as AS_TRANS if the value is bigger than 2B
  99                 if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 100                         as = AS_TRANS;
 101                 }
 102                 this.sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(
 103                                 this.localPref.getHoldTime()).setBgpIdentifier(this.localPref.getBgpId()).setBgpParameters(this.localPref.getParams()).build());
 104                 this.state = State.OpenSent;
 105
 106                 final Object lock = this;
 107                 this.timer.newTimeout(new TimerTask() {
 108                         @Override
 109                         public void run(final Timeout timeout) {
 110                                 synchronized (lock) {
 111                                         if (BGPSessionNegotiator.this.state != State.Finished) {
 112                                                 BGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 113                                                 negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 114                                                 BGPSessionNegotiator.this.state = State.Finished;
 115                                         }
 116                                 }
 117                         }
 118                 }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 119         }
 120
 121         @Override
 122         protected synchronized void handleMessage(final Notification msg) {
 123                 LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 124
 125                 switch (this.state) {
 126                 case Finished:
 127                 case Idle:
 128                         this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 129                         // FIXME: is something missing here? (at least an explanation why fall-through is okay
 130                 case OpenConfirm:
 131                         if (msg instanceof Keepalive) {
 132                                 negotiationSuccessful(this.session);
 133                         } else if (msg instanceof Notify) {
 134                                 final Notify ntf = (Notify) msg;
 135                                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 136                         }
 137                         this.state = State.Finished;
 138                         return;
 139                 case OpenSent:
 140                         if (msg instanceof Open) {
 141                                 final Open openObj = (Open) msg;
 142                                 handleOpen(openObj);
 143                                 return;
 144                         }
 145                         break;
 146                 }
 147
 148                 // Catch-all for unexpected message
 149                 LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 150                 this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 151                 negotiationFailed(new BGPDocumentedException("Unexpected message", BGPError.FSM_ERROR));
 152                 this.state = State.Finished;
 153         }
 154
 155         private static Notify buildErrorNotify(final BGPError err) {
 156                 return new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode()).build();
 157         }
 158
 159         private void handleOpen(final Open openObj) {
 160                 final AsNumber as = AsNumberUtil.advertizedAsNumber(openObj);
 161                 if (!this.remoteAs.equals(as)) {
 162                         LOG.info("Unexpected remote AS number. Expecting {}, got {}", this.remoteAs, as);
 163                         this.sendMessage(buildErrorNotify(BGPError.BAD_PEER_AS));
 164                         negotiationFailed(new BGPDocumentedException("Peer AS number mismatch", BGPError.BAD_PEER_AS));
 165                         this.state = State.Finished;
 166                         return;
 167                 }
 168
 169                 final List<BgpParameters> prefs = openObj.getBgpParameters();
 170                 if (prefs != null && !prefs.isEmpty()) {
 171                         if (!prefs.containsAll(this.localPref.getParams())) {
 172                                 LOG.info("Open message session parameters differ, session still accepted.");
 173                         }
 174                         this.sendMessage(new KeepaliveBuilder().build());
 175                         this.session = new BGPSessionImpl(this.timer, this.listener, this.channel, openObj, this.localPref.getHoldTime());
 176                         this.state = State.OpenConfirm;
 177                         LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 178                         return;
 179                 }
 180
 181                 this.sendMessage(buildErrorNotify(BGPError.UNSPECIFIC_OPEN_ERROR));
 182                 negotiationFailed(new BGPDocumentedException("Open message unacceptable. Check the configuration of BGP speaker.", BGPError.UNSPECIFIC_OPEN_ERROR));
 183                 this.state = State.Finished;
 184         }
 185
 186         public synchronized State getState() {
 187                 return this.state;
 188         }
 189 }