opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/AbstractNetconfSessionNegotiator.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
   9 package org.opendaylight.controller.netconf.util;
  10
  11 import com.google.common.base.Optional;
  12 import com.google.common.base.Preconditions;
  13 import io.netty.channel.Channel;
  14 import io.netty.channel.ChannelHandler;
  15 import io.netty.channel.ChannelHandlerContext;
  16 import io.netty.channel.ChannelInboundHandlerAdapter;
  17 import io.netty.handler.ssl.SslHandler;
  18 import io.netty.util.Timeout;
  19 import io.netty.util.Timer;
  20 import io.netty.util.TimerTask;
  21 import io.netty.util.concurrent.Future;
  22 import io.netty.util.concurrent.GenericFutureListener;
  23 import io.netty.util.concurrent.Promise;
  24 import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
  25 import org.opendaylight.controller.netconf.api.NetconfMessage;
  26 import org.opendaylight.controller.netconf.api.NetconfSessionListener;
  27 import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
  28 import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
  29 import org.opendaylight.controller.netconf.util.handler.NetconfChunkAggregator;
  30 import org.opendaylight.controller.netconf.util.handler.NetconfMessageToXMLEncoder;
  31 import org.opendaylight.controller.netconf.util.handler.NetconfXMLToMessageDecoder;
  32 import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
  33 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  34 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  35 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  36 import org.slf4j.Logger;
  37 import org.slf4j.LoggerFactory;
  38 import org.w3c.dom.Document;
  39 import org.w3c.dom.NodeList;
  40
  41 import java.util.concurrent.TimeUnit;
  42
  43 public abstract class AbstractNetconfSessionNegotiator<P extends NetconfSessionPreferences, S extends AbstractNetconfSession<S, L>, L extends NetconfSessionListener<S>>
  44 extends AbstractSessionNegotiator<NetconfHelloMessage, S> {
  45
  46     private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
  47
  48     public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
  49
  50     protected final P sessionPreferences;
  51
  52     private final L sessionListener;
  53     private Timeout timeout;
  54
  55     /**
  56      * Possible states for Finite State Machine
  57      */
  58     protected enum State {
  59         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  60     }
  61
  62     private State state = State.IDLE;
  63     private final Timer timer;
  64     private final long connectionTimeoutMillis;
  65
  66     // TODO shrink constructor
  67     protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise<S> promise, Channel channel, Timer timer,
  68             L sessionListener, long connectionTimeoutMillis) {
  69         super(promise, channel);
  70         this.sessionPreferences = sessionPreferences;
  71         this.timer = timer;
  72         this.sessionListener = sessionListener;
  73         this.connectionTimeoutMillis = connectionTimeoutMillis;
  74     }
  75
  76     @Override
  77     protected void startNegotiation() {
  78         final Optional<SslHandler> sslHandler = getSslHandler(channel);
  79         if (sslHandler.isPresent()) {
  80             Future<Channel> future = sslHandler.get().handshakeFuture();
  81             future.addListener(new GenericFutureListener<Future<? super Channel>>() {
  82                 @Override
  83                 public void operationComplete(Future<? super Channel> future) {
  84                     Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
  85                     logger.debug("Ssl handshake complete");
  86                     start();
  87                 }
  88             });
  89         } else {
  90             start();
  91         }
  92     }
  93
  94     private static Optional<SslHandler> getSslHandler(Channel channel) {
  95         final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
  96         return sslHandler == null ? Optional.<SslHandler> absent() : Optional.of(sslHandler);
  97     }
  98
  99     public P getSessionPreferences() {
 100         return sessionPreferences;
 101     }
 102
 103     private void start() {
 104         final NetconfMessage helloMessage = this.sessionPreferences.getHelloMessage();
 105         logger.debug("Session negotiation started with hello message {}", XmlUtil.toString(helloMessage.getDocument()));
 106
 107         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ExceptionHandlingInboundChannelHandler());
 108
 109         timeout = this.timer.newTimeout(new TimerTask() {
 110             @Override
 111             public void run(final Timeout timeout) {
 112                 synchronized (this) {
 113                     if (state != State.ESTABLISHED) {
 114                         logger.debug("Connection timeout after {}, session is in state {}", timeout, state);
 115                         final IllegalStateException cause = new IllegalStateException(
 116                                 "Session was not established after " + timeout);
 117                         negotiationFailed(cause);
 118                         changeState(State.FAILED);
 119                     } else if(channel.isOpen()) {
 120                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 121                     }
 122                 }
 123             }
 124         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 125
 126         // FIXME, make sessionPreferences return HelloMessage, move NetconfHelloMessage to API
 127         sendMessage((NetconfHelloMessage)helloMessage);
 128         changeState(State.OPEN_WAIT);
 129     }
 130     private void cancelTimeout() {
 131         if(timeout!=null) {
 132             timeout.cancel();
 133         }
 134     }
 135
 136     @Override
 137     protected void handleMessage(NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
 138         S session = getSessionForHelloMessage(netconfMessage)   ;
 139         negotiationSuccessful(session);
 140     }
 141
 142     protected final S getSessionForHelloMessage(NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
 143         Preconditions.checkNotNull(netconfMessage, "netconfMessage");
 144
 145         final Document doc = netconfMessage.getDocument();
 146
 147         replaceHelloMessageHandlers();
 148
 149         if (shouldUseChunkFraming(doc)) {
 150             insertChunkFramingToPipeline();
 151         }
 152
 153         changeState(State.ESTABLISHED);
 154         return getSession(sessionListener, channel, netconfMessage);
 155     }
 156
 157     /**
 158      * Insert chunk framing handlers into the pipeline
 159      */
 160     protected void insertChunkFramingToPipeline() {
 161         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
 162                 FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 163         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 164                 new NetconfChunkAggregator());
 165     }
 166
 167     protected boolean shouldUseChunkFraming(Document doc) {
 168         return containsBase11Capability(doc)
 169                 && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
 170     }
 171
 172     /**
 173      * Remove special handlers for hello message. Insert regular netconf xml message (en|de)coders.
 174      */
 175     protected void replaceHelloMessageHandlers() {
 176         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
 177         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER, new NetconfMessageToXMLEncoder());
 178     }
 179
 180     private static ChannelHandler replaceChannelHandler(Channel channel, String handlerKey, ChannelHandler decoder) {
 181         return channel.pipeline().replace(handlerKey, handlerKey, decoder);
 182     }
 183
 184     protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message) throws NetconfDocumentedException;
 185
 186     protected synchronized void changeState(final State newState) {
 187         logger.debug("Changing state from : {} to : {}", state, newState);
 188         Preconditions.checkState(isStateChangePermitted(state, newState), "Cannot change state from %s to %s", state,
 189                 newState);
 190         this.state = newState;
 191     }
 192
 193     private boolean containsBase11Capability(final Document doc) {
 194         final NodeList nList = doc.getElementsByTagName("capability");
 195         for (int i = 0; i < nList.getLength(); i++) {
 196             if (nList.item(i).getTextContent().contains("base:1.1")) {
 197                 return true;
 198             }
 199         }
 200         return false;
 201     }
 202
 203     private static boolean isStateChangePermitted(State state, State newState) {
 204         if (state == State.IDLE && newState == State.OPEN_WAIT) {
 205             return true;
 206         }
 207         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED) {
 208             return true;
 209         }
 210         if (state == State.OPEN_WAIT && newState == State.FAILED) {
 211             return true;
 212         }
 213         logger.debug("Transition from {} to {} is not allowed", state, newState);
 214         return false;
 215     }
 216
 217     /**
 218      * Handler to catch exceptions in pipeline during negotiation
 219      */
 220     private final class ExceptionHandlingInboundChannelHandler extends ChannelInboundHandlerAdapter {
 221         @Override
 222         public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
 223             logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
 224             cancelTimeout();
 225             negotiationFailed(cause);
 226             changeState(State.FAILED);
 227         }
 228     }
 229 }