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 com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12 import io.netty.channel.Channel;
  13 import io.netty.util.concurrent.Promise;
  14 import java.util.concurrent.Future;
  15 import java.util.concurrent.TimeUnit;
  16 import java.util.concurrent.TimeoutException;
  17 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  18 import org.opendaylight.protocol.pcep.spi.PCEPErrors;
  19 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Keepalive;
  20 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.KeepaliveBuilder;
  21 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.OpenBuilder;
  22 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Pcerr;
  23 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.Message;
  24 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.OpenMessage;
  25 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.keepalive.message.KeepaliveMessageBuilder;
  26 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.message.OpenMessageBuilder;
  27 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.open.object.Open;
  28 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcep.error.object.ErrorObject;
  29 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.pcerr.message.error.type.SessionCase;
  30 import org.slf4j.Logger;
  31 import org.slf4j.LoggerFactory;
  32
  33 /**
  34  * Abstract PCEP session negotiator. Takes care of basic handshake without implementing a specific policy. Policies need
  35  * to be provided by a specific subclass.
  36  */
  37 public abstract class AbstractPCEPSessionNegotiator extends AbstractSessionNegotiator<Message, PCEPSessionImpl> {
  38     /**
  39      * Unified KeepWait and OpenWait timer expiration, in seconds.
  40      */
  41     public static final int FAIL_TIMER_VALUE = 60;
  42
  43     /**
  44      * PCEP session negotiation state transitions are described in RFC5440. Simplification the two timers (KeepWait and
  45      * OpenWait) are merged into a FailTimer, as they are mutually exclusive, have the same timeout value and their
  46      * action is to terminate negotiation. This timer is restarted between state transitions and runs in all states
  47      * except Idle and Finished.
  48      */
  49     @VisibleForTesting
  50     public enum State {
  51         /**
  52          * Negotiation has not begun. It will be activated once we are asked to provide our initial proposal, at which
  53          * point we move into OpenWait state.
  54          */
  55         IDLE,
  56         /**
  57          * Waiting for the peer's OPEN message.
  58          */
  59         OPEN_WAIT,
  60         /**
  61          * Waiting for the peer's KEEPALIVE message.
  62          */
  63         KEEP_WAIT,
  64         /**
  65          * Negotiation has completed.
  66          */
  67         FINISHED,
  68     }
  69
  70     private static final Logger LOG = LoggerFactory.getLogger(AbstractPCEPSessionNegotiator.class);
  71     private static final Keepalive KEEPALIVE = new KeepaliveBuilder().setKeepaliveMessage(new KeepaliveMessageBuilder().build()).build();
  72
  73     private volatile boolean localOK, openRetry, remoteOK;
  74     private volatile State state = State.IDLE;
  75     private Future<?> failTimer;
  76     private Open localPrefs;
  77     private Open remotePrefs;
  78
  79     protected AbstractPCEPSessionNegotiator(final Promise<PCEPSessionImpl> promise, final Channel channel) {
  80         super(promise, channel);
  81     }
  82
  83     /**
  84      * Get the initial session parameters proposal.
  85      *
  86      * @return Session parameters proposal.
  87      */
  88     protected abstract Open getInitialProposal();
  89
  90     /**
  91      * Get the revised session parameters proposal based on the feedback the peer has provided to us.
  92      *
  93      * @param suggestion Peer-provided suggested session parameters
  94      * @return Session parameters proposal, or null if peers session parameters preclude us from suggesting anything
  95      */
  96     protected abstract Open getRevisedProposal(Open suggestion);
  97
  98     /**
  99      * Check whether a peer-provided session parameters proposal is acceptable.
 100      *
 101      * @param proposal peer-proposed session parameters
 102      * @return true if the proposal is acceptable, false otherwise
 103      */
 104     protected abstract boolean isProposalAcceptable(Open proposal);
 105
 106     /**
 107      * Given a peer-provided session parameters proposal which we found unacceptable, provide a counter-proposal. The
 108      * requirement is that the isProposalAcceptable() method has to return true when presented with this proposal.
 109      *
 110      * @param proposal unacceptable peer proposal
 111      * @return our counter-proposal, or null if there is no way to negotiate an acceptable proposal
 112      */
 113     protected abstract Open getCounterProposal(Open proposal);
 114
 115     /**
 116      * Create the protocol session.
 117      *
 118      * @param channel Underlying channel.
 119      * @param localPrefs Session preferences proposed by us and accepted by the peer.
 120      * @param remotePrefs Session preferences proposed by the peer and accepted by us.
 121      * @return New protocol session.
 122      */
 123     protected abstract PCEPSessionImpl createSession(Channel channel, Open localPrefs, Open remotePrefs);
 124
 125     /**
 126      * Sends PCEP Error Message with one PCEPError.
 127      *
 128      * @param value
 129      */
 130     private void sendErrorMessage(final PCEPErrors value) {
 131
 132         this.sendMessage(Util.createErrorMessage(value, null));
 133     }
 134
 135     private void scheduleFailTimer() {
 136         this.failTimer = this.channel.eventLoop().schedule(new Runnable() {
 137             @Override
 138             public void run() {
 139                 switch (AbstractPCEPSessionNegotiator.this.state) {
 140                 case FINISHED:
 141                 case IDLE:
 142                     break;
 143                 case KEEP_WAIT:
 144                     sendErrorMessage(PCEPErrors.NO_MSG_BEFORE_EXP_KEEPWAIT);
 145                     negotiationFailed(new TimeoutException("KeepWait timer expired"));
 146                     AbstractPCEPSessionNegotiator.this.state = State.FINISHED;
 147                     break;
 148                 case OPEN_WAIT:
 149                     sendErrorMessage(PCEPErrors.NO_OPEN_BEFORE_EXP_OPENWAIT);
 150                     negotiationFailed(new TimeoutException("OpenWait timer expired"));
 151                     AbstractPCEPSessionNegotiator.this.state = State.FINISHED;
 152                     break;
 153                 default:
 154                     break;
 155                 }
 156             }
 157         }, FAIL_TIMER_VALUE, TimeUnit.SECONDS);
 158     }
 159
 160     @Override
 161     protected final void startNegotiation() {
 162         Preconditions.checkState(this.state == State.IDLE);
 163         this.localPrefs = getInitialProposal();
 164         final OpenMessage m = new org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.OpenBuilder().setOpenMessage(
 165                 new OpenMessageBuilder().setOpen(this.localPrefs).build()).build();
 166         this.sendMessage(m);
 167         this.state = State.OPEN_WAIT;
 168         scheduleFailTimer();
 169
 170         LOG.info("PCEP session with {} started, sent proposal {}", this.channel, this.localPrefs);
 171     }
 172
 173     private boolean handleMessageKeepWait(final Message msg) {
 174         if (msg instanceof Keepalive) {
 175             this.localOK = true;
 176             if (this.remoteOK) {
 177                 LOG.info("PCEP peer {} completed negotiation", this.channel);
 178                 negotiationSuccessful(createSession(this.channel, this.localPrefs, this.remotePrefs));
 179                 this.state = State.FINISHED;
 180             } else {
 181                 scheduleFailTimer();
 182                 this.state = State.OPEN_WAIT;
 183                 LOG.debug("Channel {} moved to OpenWait state with localOK=1", this.channel);
 184             }
 185             return true;
 186         } else if (msg instanceof Pcerr) {
 187             final org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev131005.pcerr.message.PcerrMessage err = ((Pcerr) msg).getPcerrMessage();
 188             if (err.getErrorType() == null) {
 189                 final ErrorObject obj = err.getErrors().get(0).getErrorObject();
 190                 LOG.warn("Unexpected error received from PCC: type {} value {}", obj.getType(), obj.getValue());
 191                 negotiationFailed(new IllegalStateException("Unexpected error received from PCC."));
 192                 this.state = State.IDLE;
 193                 return true;
 194             }
 195             this.localPrefs = getRevisedProposal(((SessionCase) err.getErrorType()).getSession().getOpen());
 196             if (this.localPrefs == null) {
 197                 sendErrorMessage(PCEPErrors.PCERR_NON_ACC_SESSION_CHAR);
 198                 negotiationFailed(new IllegalStateException("Peer suggested unacceptable retry proposal"));
 199                 this.state = State.FINISHED;
 200                 return true;
 201             }
 202             this.sendMessage(new OpenBuilder().setOpenMessage(new OpenMessageBuilder().setOpen(this.localPrefs).build()).build());
 203             if (!this.remoteOK) {
 204                 this.state = State.OPEN_WAIT;
 205             }
 206             scheduleFailTimer();
 207             return true;
 208         }
 209         return false;
 210     }
 211
 212     private boolean handleMessageOpenWait(final Message msg) {
 213         if (msg instanceof org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.message.rev131007.Open) {
 214             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();
 215             final Open open = o.getOpen();
 216             if (isProposalAcceptable(open)) {
 217                 this.sendMessage(KEEPALIVE);
 218                 this.remotePrefs = open;
 219                 this.remoteOK = true;
 220                 if (this.localOK) {
 221                     negotiationSuccessful(createSession(this.channel, this.localPrefs, this.remotePrefs));
 222                     LOG.info("PCEP peer {} completed negotiation", this.channel);
 223                     this.state = State.FINISHED;
 224                 } else {
 225                     scheduleFailTimer();
 226                     this.state = State.KEEP_WAIT;
 227                     LOG.debug("Channel {} moved to KeepWait state with remoteOK=1", this.channel);
 228                 }
 229                 return true;
 230             }
 231
 232             if (this.openRetry) {
 233                 sendErrorMessage(PCEPErrors.SECOND_OPEN_MSG);
 234                 negotiationFailed(new IllegalStateException("OPEN renegotiation failed"));
 235                 this.state = State.FINISHED;
 236                 return true;
 237             }
 238
 239             final Open newPrefs = getCounterProposal(open);
 240             if (newPrefs == null) {
 241                 sendErrorMessage(PCEPErrors.NON_ACC_NON_NEG_SESSION_CHAR);
 242                 negotiationFailed(new IllegalStateException("Peer sent unacceptable session parameters"));
 243                 this.state = State.FINISHED;
 244                 return true;
 245             }
 246
 247             this.sendMessage(Util.createErrorMessage(PCEPErrors.NON_ACC_NEG_SESSION_CHAR, newPrefs));
 248
 249             this.openRetry = true;
 250             this.state = this.localOK ? State.OPEN_WAIT : State.KEEP_WAIT;
 251             scheduleFailTimer();
 252             return true;
 253         }
 254         return false;
 255     }
 256
 257     @Override
 258     protected final void handleMessage(final Message msg) {
 259         this.failTimer.cancel(false);
 260
 261         LOG.debug("Channel {} handling message {} in state {}", this.channel, msg, this.state);
 262
 263         switch (this.state) {
 264         case FINISHED:
 265         case IDLE:
 266             throw new IllegalStateException("Unexpected handleMessage in state " + this.state);
 267         case KEEP_WAIT:
 268             if (handleMessageKeepWait(msg)) {
 269                 return;
 270             }
 271             break;
 272         case OPEN_WAIT:
 273             if (handleMessageOpenWait(msg)) {
 274                 return;
 275             }
 276             break;
 277         default:
 278             break;
 279         }
 280         LOG.warn("Channel {} in state {} received unexpected message {}", this.channel, this.state, msg);
 281         sendErrorMessage(PCEPErrors.NON_OR_INVALID_OPEN_MSG);
 282         negotiationFailed(new Exception("Illegal message encountered"));
 283         this.state = State.FINISHED;
 284     }
 285
 286     @VisibleForTesting
 287     State getState() {
 288         return this.state;
 289     }
 290 }