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.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.KeepaliveMessage;
  24 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.Message;
  25 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.OpenMessage;
  26 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.PcerrMessage;
  27 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.keepalive.message.KeepaliveMessageBuilder;
  28 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.message.OpenMessageBuilder;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.object.Open;
  30 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.pcerr.message.error.type.Session;
  31 import org.slf4j.Logger;
  32 import org.slf4j.LoggerFactory;
  33
  34 import com.google.common.base.Preconditions;
  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
  74         private final Timer timer;
  75
  76         @GuardedBy("this")
  77         private State state = State.Idle;
  78
  79         @GuardedBy("this")
  80         private Timeout failTimer;
  81
  82         @GuardedBy("this")
  83         private Open localPrefs;
  84
  85         @GuardedBy("this")
  86         private Open remotePrefs;
  87
  88         private volatile boolean localOK, openRetry, remoteOK;
  89
  90         protected AbstractPCEPSessionNegotiator(final Timer timer, final Promise<PCEPSessionImpl> promise, final Channel channel) {
  91                 super(promise, channel);
  92                 this.timer = Preconditions.checkNotNull(timer);
  93         }
  94
  95         /**
  96          * Get the initial session parameters proposal.
  97          *
  98          * @return Session parameters proposal.
  99          */
 100         protected abstract Open getInitialProposal();
 101
 102         /**
 103          * Get the revised session parameters proposal based on the feedback the peer has provided to us.
 104          *
 105          * @param suggestion Peer-provided suggested session parameters
 106          * @return Session parameters proposal.
 107          */
 108         protected abstract Open getRevisedProposal(Open suggestion);
 109
 110         /**
 111          * Check whether a peer-provided session parameters proposal is acceptable.
 112          *
 113          * @param proposal peer-proposed session parameters
 114          * @return true if the proposal is acceptable, false otherwise
 115          */
 116         protected abstract boolean isProposalAcceptable(Open proposal);
 117
 118         /**
 119          * Given a peer-provided session parameters proposal which we found unacceptable, provide a counter-proposal. The
 120          * requirement is that the isProposalAcceptable() method has to return true when presented with this proposal.
 121          *
 122          * @param proposal unacceptable peer proposal
 123          * @return our counter-proposal, or null if there is no way to negotiate an acceptable proposal
 124          */
 125         protected abstract Open getCounterProposal(Open proposal);
 126
 127         /**
 128          * Create the protocol session.
 129          *
 130          * @param timer Timer which the session can use for its various functions.
 131          * @param channel Underlying channel.
 132          * @param sessionId Assigned session ID.
 133          * @param localPrefs Session preferences proposed by us and accepted by the peer.
 134          * @param remotePrefs Session preferences proposed by the peer and accepted by us.
 135          * @return New protocol session.
 136          */
 137         protected abstract PCEPSessionImpl createSession(Timer timer, Channel channel, Open localPrefs, Open remotePrefs);
 138
 139         /**
 140          * Sends PCEP Error Message with one PCEPError.
 141          *
 142          * @param value
 143          */
 144         private void sendErrorMessage(final PCEPErrors value) {
 145
 146                 this.channel.writeAndFlush(Util.createErrorMessage(value, null));
 147         }
 148
 149         private void scheduleFailTimer() {
 150                 final Object lock = this;
 151
 152                 this.failTimer = this.timer.newTimeout(new TimerTask() {
 153                         @Override
 154                         public void run(final Timeout timeout) throws Exception {
 155                                 synchronized (lock) {
 156                                         // This closes the race between timer expiring and new timer
 157                                         // being armed while it waits for the lock.
 158                                         if (AbstractPCEPSessionNegotiator.this.failTimer == timeout) {
 159                                                 switch (AbstractPCEPSessionNegotiator.this.state) {
 160                                                 case Finished:
 161                                                 case Idle:
 162                                                         break;
 163                                                 case KeepWait:
 164                                                         sendErrorMessage(PCEPErrors.NO_MSG_BEFORE_EXP_KEEPWAIT);
 165                                                         negotiationFailed(new TimeoutException("KeepWait timer expired"));
 166                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 167                                                         break;
 168                                                 case OpenWait:
 169                                                         sendErrorMessage(PCEPErrors.NO_OPEN_BEFORE_EXP_OPENWAIT);
 170                                                         negotiationFailed(new TimeoutException("OpenWait timer expired"));
 171                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 172                                                         break;
 173                                                 }
 174                                         }
 175                                 }
 176                         }
 177                 }, FAIL_TIMER_VALUE, TimeUnit.SECONDS);
 178         }
 179
 180         @Override
 181         final synchronized protected void startNegotiation() {
 182                 Preconditions.checkState(this.state == State.Idle);
 183                 this.localPrefs = getInitialProposal();
 184                 final OpenMessage m = new org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.OpenBuilder().setOpenMessage(
 185                                 new OpenMessageBuilder().setOpen(this.localPrefs).build()).build();
 186                 this.channel.writeAndFlush(m);
 187                 this.state = State.OpenWait;
 188                 scheduleFailTimer();
 189
 190                 logger.debug("Channel {} started sent proposal {}", this.channel, this.localPrefs);
 191         }
 192
 193         @Override
 194         final synchronized protected void handleMessage(final Message msg) throws Exception {
 195                 this.failTimer.cancel();
 196
 197                 logger.debug("Channel {} handling message in state {}", this.channel, this.state);
 198
 199                 switch (this.state) {
 200                 case Finished:
 201                 case Idle:
 202                         throw new IllegalStateException("Unexpected handleMessage in state " + this.state);
 203                 case KeepWait:
 204                         if (msg instanceof KeepaliveMessage) {
 205                                 this.localOK = true;
 206                                 if (this.remoteOK) {
 207                                         negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 208                                         this.state = State.Finished;
 209                                 } else {
 210                                         scheduleFailTimer();
 211                                         this.state = State.OpenWait;
 212                                         logger.debug("Channel {} moved to OpenWait state with localOK=1", this.channel);
 213                                 }
 214
 215                                 return;
 216                         } else if (msg instanceof PcerrMessage) {
 217                                 final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.PcerrMessage err = ((PcerrMessage) msg).getPcerrMessage();
 218                                 this.localPrefs = getRevisedProposal(((Session) err.getErrorType()).getOpen());
 219                                 if (this.localPrefs == null) {
 220                                         sendErrorMessage(PCEPErrors.PCERR_NON_ACC_SESSION_CHAR);
 221                                         negotiationFailed(new RuntimeException("Peer suggested unacceptable retry proposal"));
 222                                         this.state = State.Finished;
 223                                         return;
 224                                 }
 225
 226                                 if (!this.remoteOK) {
 227                                         this.state = State.OpenWait;
 228                                 }
 229                                 scheduleFailTimer();
 230                                 return;
 231                         }
 232
 233                         break;
 234                 case OpenWait:
 235                         if (msg instanceof OpenMessage) {
 236                                 final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.message.OpenMessage o = ((OpenMessage) msg).getOpenMessage();
 237                                 final Open open = o.getOpen();
 238                                 if (isProposalAcceptable(open)) {
 239                                         this.channel.writeAndFlush(new KeepaliveMessageBuilder().build());
 240                                         this.remotePrefs = open;
 241                                         this.remoteOK = true;
 242                                         if (this.localOK) {
 243                                                 negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 244                                                 this.state = State.Finished;
 245                                         } else {
 246                                                 scheduleFailTimer();
 247                                                 this.state = State.KeepWait;
 248                                                 logger.debug("Channel {} moved to KeepWait state with remoteOK=1", this.channel);
 249                                         }
 250                                         return;
 251                                 }
 252
 253                                 if (this.openRetry) {
 254                                         sendErrorMessage(PCEPErrors.SECOND_OPEN_MSG);
 255                                         negotiationFailed(new RuntimeException("OPEN renegotiation failed"));
 256                                         this.state = State.Finished;
 257                                         return;
 258                                 }
 259
 260                                 final Open newPrefs = getCounterProposal(open);
 261                                 if (newPrefs == null) {
 262                                         sendErrorMessage(PCEPErrors.NON_ACC_NON_NEG_SESSION_CHAR);
 263                                         negotiationFailed(new RuntimeException("Peer sent unacceptable session parameters"));
 264                                         this.state = State.Finished;
 265                                         return;
 266                                 }
 267
 268                                 this.channel.writeAndFlush(Util.createErrorMessage(PCEPErrors.NON_ACC_NEG_SESSION_CHAR, newPrefs));
 269
 270                                 this.openRetry = true;
 271                                 this.state = this.localOK ? State.OpenWait : State.KeepWait;
 272                                 scheduleFailTimer();
 273                                 return;
 274                         }
 275
 276                         break;
 277                 }
 278
 279                 logger.warn("Channel {} in state {} received unexpected message {}", this.channel, this.state, msg);
 280                 sendErrorMessage(PCEPErrors.NON_OR_INVALID_OPEN_MSG);
 281                 negotiationFailed(new Exception("Illegal message encountered"));
 282                 this.state = State.Finished;
 283         }
 284 }