pcep/impl/src/main/java/org/opendaylight/protocol/pcep/impl/AbstractPCEPSessionNegotiator.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.pcep.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.concurrent.TimeUnit;
  17 import java.util.concurrent.TimeoutException;
  18
  19 import javax.annotation.concurrent.GuardedBy;
  20
  21 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  22 import org.opendaylight.protocol.pcep.PCEPErrors;
  23 import org.opendaylight.protocol.pcep.message.PCEPErrorMessage;
  24 import org.opendaylight.protocol.pcep.message.PCEPOpenMessage;
  25 import org.opendaylight.protocol.pcep.object.PCEPErrorObject;
  26 import org.opendaylight.protocol.pcep.object.PCEPOpenObject;
  27 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.KeepaliveMessage;
  28 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.Message;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.keepalive.message.KeepaliveMessageBuilder;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32
  33 import com.google.common.base.Preconditions;
  34 import com.google.common.collect.ImmutableList;
  35
  36 /**
  37  * Abstract PCEP session negotiator. Takes care of basic handshake without implementing a specific policy. Policies need
  38  * to be provided by a specific subclass.
  39  */
  40 public abstract class AbstractPCEPSessionNegotiator extends AbstractSessionNegotiator<Message, PCEPSessionImpl> {
  41         /**
  42          * Unified KeepWait and OpenWait timer expiration, in seconds.
  43          */
  44         public static final int FAIL_TIMER_VALUE = 60;
  45
  46         /**
  47          * PCEP session negotiation state transitions are described in RFC5440. Simplification the two timers (KeepWait and
  48          * OpenWait) are merged into a FailTimer, as they are mutually exclusive, have the same timeout value and their
  49          * action is to terminate negotiation. This timer is restarted between state transitions and runs in all states
  50          * except Idle and Finished.
  51          */
  52         private enum State {
  53                 /**
  54                  * Negotiation has not begun. It will be activated once we are asked to provide our initial proposal, at which
  55                  * point we move into OpenWait state.
  56                  */
  57                 Idle,
  58                 /**
  59                  * Waiting for the peer's OPEN message.
  60                  */
  61                 OpenWait,
  62                 /**
  63                  * Waiting for the peer's KEEPALIVE message.
  64                  */
  65                 KeepWait,
  66                 /**
  67                  * Negotiation has completed.
  68                  */
  69                 Finished,
  70         }
  71
  72         private static final Logger logger = LoggerFactory.getLogger(AbstractPCEPSessionNegotiator.class);
  73         private final Timer timer;
  74
  75         @GuardedBy("this")
  76         private State state = State.Idle;
  77
  78         @GuardedBy("this")
  79         private Timeout failTimer;
  80
  81         @GuardedBy("this")
  82         private PCEPOpenObject localPrefs;
  83
  84         @GuardedBy("this")
  85         private PCEPOpenObject remotePrefs;
  86
  87         private volatile boolean localOK, openRetry, remoteOK;
  88
  89         protected AbstractPCEPSessionNegotiator(final Timer timer, final Promise<PCEPSessionImpl> promise, final Channel channel) {
  90                 super(promise, channel);
  91                 this.timer = Preconditions.checkNotNull(timer);
  92         }
  93
  94         /**
  95          * Get the initial session parameters proposal.
  96          *
  97          * @return Session parameters proposal.
  98          */
  99         protected abstract PCEPOpenObject getInitialProposal();
 100
 101         /**
 102          * Get the revised session parameters proposal based on the feedback the peer has provided to us.
 103          *
 104          * @param suggestion Peer-provided suggested session parameters
 105          * @return Session parameters proposal.
 106          */
 107         protected abstract PCEPOpenObject getRevisedProposal(PCEPOpenObject suggestion);
 108
 109         /**
 110          * Check whether a peer-provided session parameters proposal is acceptable.
 111          *
 112          * @param proposal peer-proposed session parameters
 113          * @return true if the proposal is acceptable, false otherwise
 114          */
 115         protected abstract boolean isProposalAcceptable(PCEPOpenObject proposal);
 116
 117         /**
 118          * Given a peer-provided session parameters proposal which we found unacceptable, provide a counter-proposal. The
 119          * requirement is that the isProposalAcceptable() method has to return true when presented with this proposal.
 120          *
 121          * @param proposal unacceptable peer proposal
 122          * @return our counter-proposal, or null if there is no way to negotiate an acceptable proposal
 123          */
 124         protected abstract PCEPOpenObject getCounterProposal(PCEPOpenObject proposal);
 125
 126         /**
 127          * Create the protocol session.
 128          *
 129          * @param timer Timer which the session can use for its various functions.
 130          * @param channel Underlying channel.
 131          * @param sessionId Assigned session ID.
 132          * @param localPrefs Session preferences proposed by us and accepted by the peer.
 133          * @param remotePrefs Session preferences proposed by the peer and accepted by us.
 134          * @return New protocol session.
 135          */
 136         protected abstract PCEPSessionImpl createSession(Timer timer, Channel channel, PCEPOpenObject localPrefs, PCEPOpenObject remotePrefs);
 137
 138         /**
 139          * Sends PCEP Error Message with one PCEPError.
 140          *
 141          * @param value
 142          */
 143         private void sendErrorMessage(final PCEPErrors value) {
 144                 this.channel.writeAndFlush(new PCEPErrorMessage(ImmutableList.of(new PCEPErrorObject(value))));
 145         }
 146
 147         private void scheduleFailTimer() {
 148                 final Object lock = this;
 149
 150                 this.failTimer = this.timer.newTimeout(new TimerTask() {
 151                         @Override
 152                         public void run(final Timeout timeout) throws Exception {
 153                                 synchronized (lock) {
 154                                         // This closes the race between timer expiring and new timer
 155                                         // being armed while it waits for the lock.
 156                                         if (AbstractPCEPSessionNegotiator.this.failTimer == timeout) {
 157                                                 switch (AbstractPCEPSessionNegotiator.this.state) {
 158                                                 case Finished:
 159                                                 case Idle:
 160                                                         break;
 161                                                 case KeepWait:
 162                                                         sendErrorMessage(PCEPErrors.NO_MSG_BEFORE_EXP_KEEPWAIT);
 163                                                         negotiationFailed(new TimeoutException("KeepWait timer expired"));
 164                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 165                                                         break;
 166                                                 case OpenWait:
 167                                                         sendErrorMessage(PCEPErrors.NO_OPEN_BEFORE_EXP_OPENWAIT);
 168                                                         negotiationFailed(new TimeoutException("OpenWait timer expired"));
 169                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 170                                                         break;
 171                                                 }
 172                                         }
 173                                 }
 174                         }
 175                 }, FAIL_TIMER_VALUE, TimeUnit.SECONDS);
 176         }
 177
 178         @Override
 179         final synchronized protected void startNegotiation() {
 180                 Preconditions.checkState(this.state == State.Idle);
 181                 this.localPrefs = getInitialProposal();
 182                 this.channel.writeAndFlush(new PCEPOpenMessage(this.localPrefs));
 183                 this.state = State.OpenWait;
 184                 scheduleFailTimer();
 185
 186                 logger.debug("Channel {} started sent proposal {}", this.channel, this.localPrefs);
 187         }
 188
 189         @Override
 190         final synchronized protected void handleMessage(final Message msg) throws Exception {
 191                 this.failTimer.cancel();
 192
 193                 logger.debug("Channel {} handling message in state {}", this.channel, this.state);
 194
 195                 switch (this.state) {
 196                 case Finished:
 197                 case Idle:
 198                         throw new IllegalStateException("Unexpected handleMessage in state " + this.state);
 199                 case KeepWait:
 200                         if (msg instanceof KeepaliveMessage) {
 201                                 this.localOK = true;
 202                                 if (this.remoteOK) {
 203                                         negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 204                                         this.state = State.Finished;
 205                                 } else {
 206                                         scheduleFailTimer();
 207                                         this.state = State.OpenWait;
 208                                         logger.debug("Channel {} moved to OpenWait state with localOK=1", this.channel);
 209                                 }
 210
 211                                 return;
 212                         } else if (msg instanceof PCEPErrorMessage) {
 213                                 final PCEPErrorMessage err = (PCEPErrorMessage) msg;
 214                                 this.localPrefs = getRevisedProposal(err.getOpenObject());
 215                                 if (this.localPrefs == null) {
 216                                         sendErrorMessage(PCEPErrors.PCERR_NON_ACC_SESSION_CHAR);
 217                                         negotiationFailed(new RuntimeException("Peer suggested unacceptable retry proposal"));
 218                                         this.state = State.Finished;
 219                                         return;
 220                                 }
 221
 222                                 if (!this.remoteOK) {
 223                                         this.state = State.OpenWait;
 224                                 }
 225                                 scheduleFailTimer();
 226                                 return;
 227                         }
 228
 229                         break;
 230                 case OpenWait:
 231                         if (msg instanceof PCEPOpenMessage) {
 232                                 final PCEPOpenObject open = ((PCEPOpenMessage) msg).getOpenObject();
 233                                 if (isProposalAcceptable(open)) {
 234                                         this.channel.writeAndFlush(new KeepaliveMessageBuilder().build());
 235                                         this.remotePrefs = open;
 236                                         this.remoteOK = true;
 237                                         if (this.localOK) {
 238                                                 negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 239                                                 this.state = State.Finished;
 240                                         } else {
 241                                                 scheduleFailTimer();
 242                                                 this.state = State.KeepWait;
 243                                                 logger.debug("Channel {} moved to KeepWait state with remoteOK=1", this.channel);
 244                                         }
 245                                         return;
 246                                 }
 247
 248                                 if (this.openRetry) {
 249                                         sendErrorMessage(PCEPErrors.SECOND_OPEN_MSG);
 250                                         negotiationFailed(new RuntimeException("OPEN renegotiation failed"));
 251                                         this.state = State.Finished;
 252                                         return;
 253                                 }
 254
 255                                 final PCEPOpenObject newPrefs = getCounterProposal(open);
 256                                 if (newPrefs == null) {
 257                                         sendErrorMessage(PCEPErrors.NON_ACC_NON_NEG_SESSION_CHAR);
 258                                         negotiationFailed(new RuntimeException("Peer sent unacceptable session parameters"));
 259                                         this.state = State.Finished;
 260                                         return;
 261                                 }
 262
 263                                 this.channel.writeAndFlush(new PCEPErrorMessage(newPrefs, ImmutableList.of(new PCEPErrorObject(PCEPErrors.NON_ACC_NEG_SESSION_CHAR)), null));
 264
 265                                 this.openRetry = true;
 266                                 this.state = this.localOK ? State.OpenWait : State.KeepWait;
 267                                 scheduleFailTimer();
 268                                 return;
 269                         }
 270
 271                         break;
 272                 }
 273
 274                 logger.warn("Channel {} in state {} received unexpected message {}", this.channel, this.state, msg);
 275                 sendErrorMessage(PCEPErrors.NON_OR_INVALID_OPEN_MSG);
 276                 negotiationFailed(new Exception("Illegal message encountered"));
 277                 this.state = State.Finished;
 278         }
 279 }