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.spi.PCEPErrors;
  23 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Keepalive;
  24 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.KeepaliveBuilder;
  25 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.OpenBuilder;
  26 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Pcerr;
  27 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.Message;
  28 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.OpenMessage;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.keepalive.message.KeepaliveMessageBuilder;
  30 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.message.OpenMessageBuilder;
  31 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.object.Open;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.pcerr.message.error.type.SessionCase;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 import com.google.common.annotations.VisibleForTesting;
  37 import com.google.common.base.Preconditions;
  38
  39 /**
  40  * Abstract PCEP session negotiator. Takes care of basic handshake without implementing a specific policy. Policies need
  41  * to be provided by a specific subclass.
  42  */
  43 public abstract class AbstractPCEPSessionNegotiator extends AbstractSessionNegotiator<Message, PCEPSessionImpl> {
  44         /**
  45          * Unified KeepWait and OpenWait timer expiration, in seconds.
  46          */
  47         public static final int FAIL_TIMER_VALUE = 60;
  48
  49         /**
  50          * PCEP session negotiation state transitions are described in RFC5440. Simplification the two timers (KeepWait and
  51          * OpenWait) are merged into a FailTimer, as they are mutually exclusive, have the same timeout value and their
  52          * action is to terminate negotiation. This timer is restarted between state transitions and runs in all states
  53          * except Idle and Finished.
  54          */
  55         @VisibleForTesting
  56         public enum State {
  57                 /**
  58                  * Negotiation has not begun. It will be activated once we are asked to provide our initial proposal, at which
  59                  * point we move into OpenWait state.
  60                  */
  61                 Idle,
  62                 /**
  63                  * Waiting for the peer's OPEN message.
  64                  */
  65                 OpenWait,
  66                 /**
  67                  * Waiting for the peer's KEEPALIVE message.
  68                  */
  69                 KeepWait,
  70                 /**
  71                  * Negotiation has completed.
  72                  */
  73                 Finished,
  74         }
  75
  76         private static final Logger LOG = LoggerFactory.getLogger(AbstractPCEPSessionNegotiator.class);
  77
  78         private final Timer timer;
  79
  80         @GuardedBy("this")
  81         private State state = State.Idle;
  82
  83         @GuardedBy("this")
  84         private Timeout failTimer;
  85
  86         @GuardedBy("this")
  87         private Open localPrefs;
  88
  89         @GuardedBy("this")
  90         private Open remotePrefs;
  91
  92         private volatile boolean localOK, openRetry, remoteOK;
  93
  94         private final Keepalive keepalive = new KeepaliveBuilder().setKeepaliveMessage(new KeepaliveMessageBuilder().build()).build();
  95
  96         protected AbstractPCEPSessionNegotiator(final Timer timer, final Promise<PCEPSessionImpl> promise, final Channel channel) {
  97                 super(promise, channel);
  98                 this.timer = Preconditions.checkNotNull(timer);
  99         }
 100
 101         /**
 102          * Get the initial session parameters proposal.
 103          *
 104          * @return Session parameters proposal.
 105          */
 106         protected abstract Open getInitialProposal();
 107
 108         /**
 109          * Get the revised session parameters proposal based on the feedback the peer has provided to us.
 110          *
 111          * @param suggestion Peer-provided suggested session parameters
 112          * @return Session parameters proposal, or null if peers session parameters preclude us from suggesting anything
 113          */
 114         protected abstract Open getRevisedProposal(Open suggestion);
 115
 116         /**
 117          * Check whether a peer-provided session parameters proposal is acceptable.
 118          *
 119          * @param proposal peer-proposed session parameters
 120          * @return true if the proposal is acceptable, false otherwise
 121          */
 122         protected abstract boolean isProposalAcceptable(Open proposal);
 123
 124         /**
 125          * Given a peer-provided session parameters proposal which we found unacceptable, provide a counter-proposal. The
 126          * requirement is that the isProposalAcceptable() method has to return true when presented with this proposal.
 127          *
 128          * @param proposal unacceptable peer proposal
 129          * @return our counter-proposal, or null if there is no way to negotiate an acceptable proposal
 130          */
 131         protected abstract Open getCounterProposal(Open proposal);
 132
 133         /**
 134          * Create the protocol session.
 135          *
 136          * @param timer Timer which the session can use for its various functions.
 137          * @param channel Underlying channel.
 138          * @param sessionId Assigned session ID.
 139          * @param localPrefs Session preferences proposed by us and accepted by the peer.
 140          * @param remotePrefs Session preferences proposed by the peer and accepted by us.
 141          * @return New protocol session.
 142          */
 143         protected abstract PCEPSessionImpl createSession(Timer timer, Channel channel, Open localPrefs, Open remotePrefs);
 144
 145         /**
 146          * Sends PCEP Error Message with one PCEPError.
 147          *
 148          * @param value
 149          */
 150         private void sendErrorMessage(final PCEPErrors value) {
 151
 152                 this.channel.writeAndFlush(Util.createErrorMessage(value, null));
 153         }
 154
 155         private void scheduleFailTimer() {
 156                 final Object lock = this;
 157
 158                 this.failTimer = this.timer.newTimeout(new TimerTask() {
 159                         @Override
 160                         public void run(final Timeout timeout) {
 161                                 synchronized (lock) {
 162                                         // This closes the race between timer expiring and new timer
 163                                         // being armed while it waits for the lock.
 164                                         if (AbstractPCEPSessionNegotiator.this.failTimer == timeout) {
 165                                                 switch (AbstractPCEPSessionNegotiator.this.state) {
 166                                                 case Finished:
 167                                                 case Idle:
 168                                                         break;
 169                                                 case KeepWait:
 170                                                         sendErrorMessage(PCEPErrors.NO_MSG_BEFORE_EXP_KEEPWAIT);
 171                                                         negotiationFailed(new TimeoutException("KeepWait timer expired"));
 172                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 173                                                         break;
 174                                                 case OpenWait:
 175                                                         sendErrorMessage(PCEPErrors.NO_OPEN_BEFORE_EXP_OPENWAIT);
 176                                                         negotiationFailed(new TimeoutException("OpenWait timer expired"));
 177                                                         AbstractPCEPSessionNegotiator.this.state = State.Finished;
 178                                                         break;
 179                                                 }
 180                                         }
 181                                 }
 182                         }
 183                 }, FAIL_TIMER_VALUE, TimeUnit.SECONDS);
 184         }
 185
 186         @Override
 187         protected final synchronized void startNegotiation() {
 188                 Preconditions.checkState(this.state == State.Idle);
 189                 this.localPrefs = getInitialProposal();
 190                 final OpenMessage m = new org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.OpenBuilder().setOpenMessage(
 191                                 new OpenMessageBuilder().setOpen(this.localPrefs).build()).build();
 192                 this.channel.writeAndFlush(m);
 193                 this.state = State.OpenWait;
 194                 scheduleFailTimer();
 195
 196                 LOG.debug("Channel {} started sent proposal {}", this.channel, this.localPrefs);
 197         }
 198
 199         @Override
 200         protected final synchronized void handleMessage(final Message msg) {
 201                 this.failTimer.cancel();
 202
 203                 LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 204
 205                 switch (this.state) {
 206                 case Finished:
 207                 case Idle:
 208                         throw new IllegalStateException("Unexpected handleMessage in state " + this.state);
 209                 case KeepWait:
 210                         if (msg instanceof Keepalive) {
 211                                 this.localOK = true;
 212                                 if (this.remoteOK) {
 213                                         LOG.info("Channel {} completed negotiation", this.channel);
 214                                         negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 215                                         this.state = State.Finished;
 216                                 } else {
 217                                         scheduleFailTimer();
 218                                         this.state = State.OpenWait;
 219                                         LOG.debug("Channel {} moved to OpenWait state with localOK=1", this.channel);
 220                                 }
 221
 222                                 return;
 223                         } else if (msg instanceof Pcerr) {
 224                                 final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.PcerrMessage err = ((Pcerr) msg).getPcerrMessage();
 225                                 this.localPrefs = getRevisedProposal(((SessionCase) err.getErrorType()).getSession().getOpen());
 226                                 if (this.localPrefs == null) {
 227                                         sendErrorMessage(PCEPErrors.PCERR_NON_ACC_SESSION_CHAR);
 228                                         negotiationFailed(new RuntimeException("Peer suggested unacceptable retry proposal"));
 229                                         this.state = State.Finished;
 230                                         return;
 231                                 }
 232                                 this.channel.writeAndFlush(new OpenBuilder().setOpenMessage(new OpenMessageBuilder().setOpen(this.localPrefs).build()).build());
 233                                 if (!this.remoteOK) {
 234                                         this.state = State.OpenWait;
 235                                 }
 236                                 scheduleFailTimer();
 237                                 return;
 238                         }
 239
 240                         break;
 241                 case OpenWait:
 242                         if (msg instanceof org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Open) {
 243                                 final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.message.OpenMessage o = ((org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Open) msg).getOpenMessage();
 244                                 final Open open = o.getOpen();
 245                                 if (isProposalAcceptable(open)) {
 246                                         this.channel.writeAndFlush(this.keepalive);
 247                                         this.remotePrefs = open;
 248                                         this.remoteOK = true;
 249                                         if (this.localOK) {
 250                                                 negotiationSuccessful(createSession(this.timer, this.channel, this.localPrefs, this.remotePrefs));
 251                                                 this.state = State.Finished;
 252                                         } else {
 253                                                 scheduleFailTimer();
 254                                                 this.state = State.KeepWait;
 255                                                 LOG.debug("Channel {} moved to KeepWait state with remoteOK=1", this.channel);
 256                                         }
 257                                         return;
 258                                 }
 259
 260                                 if (this.openRetry) {
 261                                         sendErrorMessage(PCEPErrors.SECOND_OPEN_MSG);
 262                                         negotiationFailed(new RuntimeException("OPEN renegotiation failed"));
 263                                         this.state = State.Finished;
 264                                         return;
 265                                 }
 266
 267                                 final Open newPrefs = getCounterProposal(open);
 268                                 if (newPrefs == null) {
 269                                         sendErrorMessage(PCEPErrors.NON_ACC_NON_NEG_SESSION_CHAR);
 270                                         negotiationFailed(new RuntimeException("Peer sent unacceptable session parameters"));
 271                                         this.state = State.Finished;
 272                                         return;
 273                                 }
 274
 275                                 this.channel.writeAndFlush(Util.createErrorMessage(PCEPErrors.NON_ACC_NEG_SESSION_CHAR, newPrefs));
 276
 277                                 this.openRetry = true;
 278                                 this.state = this.localOK ? State.OpenWait : State.KeepWait;
 279                                 scheduleFailTimer();
 280                                 return;
 281                         }
 282
 283                         break;
 284                 }
 285
 286                 LOG.warn("Channel {} in state {} received unexpected message {}", this.channel, this.state, msg);
 287                 sendErrorMessage(PCEPErrors.NON_OR_INVALID_OPEN_MSG);
 288                 negotiationFailed(new Exception("Illegal message encountered"));
 289                 this.state = State.Finished;
 290         }
 291
 292         public synchronized State getState() {
 293                 return this.state;
 294         }
 295 }