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 io.netty.channel.Channel;
  12 import io.netty.channel.ChannelHandler;
  13 import io.netty.channel.ChannelHandlerContext;
  14 import io.netty.handler.ssl.SslHandler;
  15 import io.netty.util.Timeout;
  16 import io.netty.util.Timer;
  17 import io.netty.util.TimerTask;
  18 import io.netty.util.concurrent.Future;
  19 import io.netty.util.concurrent.GenericFutureListener;
  20 import io.netty.util.concurrent.Promise;
  21
  22 import java.util.concurrent.TimeUnit;
  23
  24 import io.netty.channel.ChannelInboundHandlerAdapter;
  25 import org.opendaylight.controller.netconf.api.AbstractNetconfSession;
  26 import org.opendaylight.controller.netconf.api.NetconfMessage;
  27 import org.opendaylight.controller.netconf.api.NetconfSessionListener;
  28 import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
  29 import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
  30 import org.opendaylight.controller.netconf.util.handler.NetconfChunkAggregator;
  31 import org.opendaylight.controller.netconf.util.handler.NetconfMessageToXMLEncoder;
  32 import org.opendaylight.controller.netconf.util.handler.NetconfXMLToMessageDecoder;
  33 import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
  34 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  35 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  36 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  37 import org.slf4j.Logger;
  38 import org.slf4j.LoggerFactory;
  39 import org.w3c.dom.Document;
  40 import org.w3c.dom.NodeList;
  41
  42 import com.google.common.base.Optional;
  43 import com.google.common.base.Preconditions;
  44
  45 public abstract class AbstractNetconfSessionNegotiator<P extends NetconfSessionPreferences, S extends AbstractNetconfSession<S, L>, L extends NetconfSessionListener<S>>
  46 extends AbstractSessionNegotiator<NetconfHelloMessage, S> {
  47
  48     private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
  49     public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
  50
  51     private final P sessionPreferences;
  52
  53     private final L sessionListener;
  54     private Timeout timeout;
  55
  56     /**
  57      * Possible states for Finite State Machine
  58      */
  59     private enum State {
  60         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  61     }
  62
  63     private State state = State.IDLE;
  64     private final Timer timer;
  65     private final long connectionTimeoutMillis;
  66
  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         sendMessage(helloMessage);
 127         changeState(State.OPEN_WAIT);
 128     }
 129
 130     private void cancelTimeout() {
 131         if(timeout!=null) {
 132             timeout.cancel();
 133         }
 134     }
 135
 136     private void sendMessage(NetconfMessage message) {
 137         this.channel.writeAndFlush(message);
 138     }
 139
 140     @Override
 141     protected void handleMessage(NetconfHelloMessage netconfMessage) {
 142         Preconditions.checkNotNull(netconfMessage != null, "netconfMessage");
 143
 144         final Document doc = netconfMessage.getDocument();
 145
 146         replaceHelloMessageHandlers();
 147
 148         if (shouldUseChunkFraming(doc)) {
 149             insertChunkFramingToPipeline();
 150         }
 151
 152         changeState(State.ESTABLISHED);
 153         S session = getSession(sessionListener, channel, netconfMessage);
 154
 155         negotiationSuccessful(session);
 156     }
 157
 158     /**
 159      * Insert chunk framing handlers into the pipeline
 160      */
 161     private void insertChunkFramingToPipeline() {
 162         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
 163                 FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 164         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 165                 new NetconfChunkAggregator());
 166     }
 167
 168     private boolean shouldUseChunkFraming(Document doc) {
 169         return containsBase11Capability(doc)
 170                 && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
 171     }
 172
 173     /**
 174      * Remove special handlers for hello message. Insert regular netconf xml message (en|de)coders.
 175      */
 176     private void replaceHelloMessageHandlers() {
 177         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
 178         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER, new NetconfMessageToXMLEncoder());
 179     }
 180
 181     private static ChannelHandler replaceChannelHandler(Channel channel, String handlerKey, ChannelHandler decoder) {
 182         return channel.pipeline().replace(handlerKey, handlerKey, decoder);
 183     }
 184
 185     protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message);
 186
 187     private synchronized void changeState(final State newState) {
 188         logger.debug("Changing state from : {} to : {}", state, newState);
 189         Preconditions.checkState(isStateChangePermitted(state, newState), "Cannot change state from %s to %s", state,
 190                 newState);
 191         this.state = newState;
 192     }
 193
 194     private boolean containsBase11Capability(final Document doc) {
 195         final NodeList nList = doc.getElementsByTagName("capability");
 196         for (int i = 0; i < nList.getLength(); i++) {
 197             if (nList.item(i).getTextContent().contains("base:1.1")) {
 198                 return true;
 199             }
 200         }
 201         return false;
 202     }
 203
 204     private static boolean isStateChangePermitted(State state, State newState) {
 205         if (state == State.IDLE && newState == State.OPEN_WAIT) {
 206             return true;
 207         }
 208         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED) {
 209             return true;
 210         }
 211         if (state == State.OPEN_WAIT && newState == State.FAILED) {
 212             return true;
 213         }
 214
 215         logger.debug("Transition from {} to {} is not allowed", state, newState);
 216         return false;
 217     }
 218
 219     /**
 220      * Handler to catch exceptions in pipeline during negotiation
 221      */
 222     private final class ExceptionHandlingInboundChannelHandler extends ChannelInboundHandlerAdapter {
 223
 224         @Override
 225         public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
 226             logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
 227             cancelTimeout();
 228             negotiationFailed(cause);
 229             changeState(State.FAILED);
 230         }
 231     }
 232 }