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 java.util.concurrent.TimeUnit;
  12
  13 import org.opendaylight.controller.netconf.api.AbstractNetconfSession;
  14 import org.opendaylight.controller.netconf.api.NetconfMessage;
  15 import org.opendaylight.controller.netconf.api.NetconfSessionListener;
  16 import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
  17 import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
  18 import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
  19 import org.opendaylight.controller.netconf.util.handler.NetconfMessageAggregator;
  20 import org.opendaylight.controller.netconf.util.handler.NetconfMessageChunkDecoder;
  21 import org.opendaylight.controller.netconf.util.handler.NetconfMessageToXMLEncoder;
  22 import org.opendaylight.controller.netconf.util.handler.NetconfXMLToMessageDecoder;
  23 import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
  24 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  25 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28 import org.w3c.dom.Document;
  29 import org.w3c.dom.NodeList;
  30
  31 import com.google.common.base.Optional;
  32 import com.google.common.base.Preconditions;
  33
  34 import io.netty.channel.Channel;
  35 import io.netty.channel.ChannelHandler;
  36 import io.netty.channel.ChannelHandlerContext;
  37 import io.netty.handler.ssl.SslHandler;
  38 import io.netty.util.Timeout;
  39 import io.netty.util.Timer;
  40 import io.netty.util.TimerTask;
  41 import io.netty.util.concurrent.Future;
  42 import io.netty.util.concurrent.GenericFutureListener;
  43 import io.netty.util.concurrent.Promise;
  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     public static final String CHUNK_DECODER_CHANNEL_HANDLER_KEY = "chunkDecoder";
  51
  52     protected final P sessionPreferences;
  53
  54     private final L sessionListener;
  55     private Timeout timeout;
  56
  57     /**
  58      * Possible states for Finite State Machine
  59      */
  60     private enum State {
  61         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  62     }
  63
  64     private State state = State.IDLE;
  65     private final Timer timer;
  66     private final long connectionTimeoutMillis;
  67
  68     protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise<S> promise, Channel channel, Timer timer,
  69             L sessionListener, long connectionTimeoutMillis) {
  70         super(promise, channel);
  71         this.sessionPreferences = sessionPreferences;
  72         this.timer = timer;
  73         this.sessionListener = sessionListener;
  74         this.connectionTimeoutMillis = connectionTimeoutMillis;
  75     }
  76
  77     @Override
  78     protected void startNegotiation() {
  79         final Optional<SslHandler> sslHandler = getSslHandler(channel);
  80         if (sslHandler.isPresent()) {
  81             Future<Channel> future = sslHandler.get().handshakeFuture();
  82             future.addListener(new GenericFutureListener<Future<? super Channel>>() {
  83                 @Override
  84                 public void operationComplete(Future<? super Channel> future) throws Exception {
  85                     Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
  86                     logger.debug("Ssl handshake complete");
  87                     start();
  88                 }
  89             });
  90         } else
  91             start();
  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     private void start() {
 100         final NetconfMessage helloMessage = this.sessionPreferences.getHelloMessage();
 101         logger.debug("Session negotiation started with hello message {}", XmlUtil.toString(helloMessage.getDocument()));
 102
 103         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ChannelHandler() {
 104             @Override
 105             public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
 106             }
 107
 108             @Override
 109             public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
 110             }
 111
 112             @Override
 113             public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
 114                 logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
 115                 cancelTimeout();
 116                 negotiationFailed(cause);
 117                 changeState(State.FAILED);
 118             }
 119         });
 120
 121         timeout = this.timer.newTimeout(new TimerTask() {
 122             @Override
 123             public void run(final Timeout timeout) throws Exception {
 124                 synchronized (this) {
 125                     if (state != State.ESTABLISHED) {
 126                         logger.debug("Connection timeout after {}, session is in state {}", timeout, state);
 127                         final IllegalStateException cause = new IllegalStateException(
 128                                 "Session was not established after " + timeout);
 129                         negotiationFailed(cause);
 130                         changeState(State.FAILED);
 131                     } else if(channel.isOpen()) {
 132                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 133                     }
 134                 }
 135             }
 136         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 137
 138         sendMessage(helloMessage);
 139         changeState(State.OPEN_WAIT);
 140     }
 141
 142     private void cancelTimeout() {
 143         if(timeout!=null)
 144             timeout.cancel();
 145     }
 146
 147     private void sendMessage(NetconfMessage message) {
 148         this.channel.writeAndFlush(message);
 149     }
 150
 151     @Override
 152     protected void handleMessage(NetconfHelloMessage netconfMessage) {
 153         final Document doc = netconfMessage.getDocument();
 154
 155         // Only Hello message should arrive during negotiation
 156         if (netconfMessage instanceof NetconfHelloMessage) {
 157
 158             replaceHelloMessageHandlers();
 159
 160             if (shouldUseChunkFraming(doc)) {
 161                 insertChunkFramingToPipeline();
 162             }
 163
 164             changeState(State.ESTABLISHED);
 165             S session = getSession(sessionListener, channel, (NetconfHelloMessage)netconfMessage);
 166
 167             negotiationSuccessful(session);
 168         } else {
 169             final IllegalStateException cause = new IllegalStateException(
 170                     "Received message was not hello as expected, but was " + XmlUtil.toString(doc));
 171             logger.warn("Negotiation of netconf session failed", cause);
 172             negotiationFailed(cause);
 173         }
 174     }
 175
 176     /**
 177      * Insert chunk framing handlers into the pipeline
 178      */
 179     private void insertChunkFramingToPipeline() {
 180         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
 181                 FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 182         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 183                 new NetconfMessageAggregator(FramingMechanism.CHUNK));
 184         channel.pipeline().addAfter(AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 185                 CHUNK_DECODER_CHANNEL_HANDLER_KEY, new NetconfMessageChunkDecoder());
 186     }
 187
 188     private boolean shouldUseChunkFraming(Document doc) {
 189         return containsBase11Capability(doc)
 190                 && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
 191     }
 192
 193     /**
 194      * Remove special handlers for hello message. Insert regular netconf xml message (en|de)coders.
 195      */
 196     private void replaceHelloMessageHandlers() {
 197         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
 198         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER, new NetconfMessageToXMLEncoder());
 199     }
 200
 201     private static ChannelHandler replaceChannelHandler(Channel channel, String handlerKey, ChannelHandler decoder) {
 202         return channel.pipeline().replace(handlerKey, handlerKey, decoder);
 203     }
 204
 205     protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message);
 206
 207     private synchronized void changeState(final State newState) {
 208         logger.debug("Changing state from : {} to : {}", state, newState);
 209         Preconditions.checkState(isStateChangePermitted(state, newState), "Cannot change state from %s to %s", state,
 210                 newState);
 211         this.state = newState;
 212     }
 213
 214     private boolean containsBase11Capability(final Document doc) {
 215         final NodeList nList = doc.getElementsByTagName("capability");
 216         for (int i = 0; i < nList.getLength(); i++) {
 217             if (nList.item(i).getTextContent().contains("base:1.1")) {
 218                 return true;
 219             }
 220         }
 221         return false;
 222     }
 223
 224     private static boolean isStateChangePermitted(State state, State newState) {
 225         if (state == State.IDLE && newState == State.OPEN_WAIT)
 226             return true;
 227         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED)
 228             return true;
 229         if (state == State.OPEN_WAIT && newState == State.FAILED)
 230             return true;
 231
 232         logger.debug("Transition from {} to {} is not allowed", state, newState);
 233         return false;
 234     }
 235 }