netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/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.netconf.nettyutil;
  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.ChannelFuture;
  15 import io.netty.channel.ChannelHandler;
  16 import io.netty.channel.ChannelHandlerContext;
  17 import io.netty.channel.ChannelInboundHandlerAdapter;
  18 import io.netty.handler.ssl.SslHandler;
  19 import io.netty.util.Timeout;
  20 import io.netty.util.Timer;
  21 import io.netty.util.TimerTask;
  22 import io.netty.util.concurrent.Future;
  23 import io.netty.util.concurrent.GenericFutureListener;
  24 import io.netty.util.concurrent.Promise;
  25 import java.util.concurrent.TimeUnit;
  26 import org.opendaylight.netconf.api.NetconfDocumentedException;
  27 import org.opendaylight.netconf.api.NetconfMessage;
  28 import org.opendaylight.netconf.api.NetconfSessionListener;
  29 import org.opendaylight.netconf.api.NetconfSessionPreferences;
  30 import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
  31 import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
  32 import org.opendaylight.netconf.nettyutil.handler.FramingMechanismHandlerFactory;
  33 import org.opendaylight.netconf.nettyutil.handler.NetconfChunkAggregator;
  34 import org.opendaylight.netconf.nettyutil.handler.NetconfMessageToXMLEncoder;
  35 import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToHelloMessageDecoder;
  36 import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToMessageDecoder;
  37 import org.opendaylight.netconf.util.messages.FramingMechanism;
  38 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  39 import org.slf4j.Logger;
  40 import org.slf4j.LoggerFactory;
  41 import org.w3c.dom.Document;
  42 import org.w3c.dom.NodeList;
  43
  44 public abstract class AbstractNetconfSessionNegotiator<P extends NetconfSessionPreferences,
  45         S extends AbstractNetconfSession<S, L>, L extends NetconfSessionListener<S>>
  46     extends AbstractSessionNegotiator<NetconfHelloMessage, S> {
  47
  48     private static final Logger LOG = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
  49
  50     public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
  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     protected enum State {
  61         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  62     }
  63
  64     private State state = State.IDLE;
  65     private final Promise<S> promise;
  66     private final Timer timer;
  67     private final long connectionTimeoutMillis;
  68
  69     protected AbstractNetconfSessionNegotiator(final P sessionPreferences, final Promise<S> promise,
  70                                                final Channel channel, final Timer timer,
  71                                                final L sessionListener, final long connectionTimeoutMillis) {
  72         super(promise, channel);
  73         this.sessionPreferences = sessionPreferences;
  74         this.promise = promise;
  75         this.timer = timer;
  76         this.sessionListener = sessionListener;
  77         this.connectionTimeoutMillis = connectionTimeoutMillis;
  78     }
  79
  80     @Override
  81     protected final void startNegotiation() {
  82         if (ifNegotiatedAlready()) {
  83             LOG.debug("Negotiation on channel {} already started", channel);
  84         } else {
  85             final Optional<SslHandler> sslHandler = getSslHandler(channel);
  86             if (sslHandler.isPresent()) {
  87                 Future<Channel> future = sslHandler.get().handshakeFuture();
  88                 future.addListener(new GenericFutureListener<Future<? super Channel>>() {
  89                     @Override
  90                     public void operationComplete(final Future<? super Channel> future) {
  91                         Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
  92                         LOG.debug("Ssl handshake complete");
  93                         start();
  94                     }
  95                 });
  96             } else {
  97                 start();
  98             }
  99         }
 100     }
 101
 102     protected final boolean ifNegotiatedAlready() {
 103         // Indicates whether negotiation already started
 104         return this.state != State.IDLE;
 105     }
 106
 107     private static Optional<SslHandler> getSslHandler(final Channel channel) {
 108         final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
 109         return sslHandler == null ? Optional.<SslHandler>absent() : Optional.of(sslHandler);
 110     }
 111
 112     public P getSessionPreferences() {
 113         return sessionPreferences;
 114     }
 115
 116     private void start() {
 117         final NetconfHelloMessage helloMessage = this.sessionPreferences.getHelloMessage();
 118         LOG.debug("Session negotiation started with hello message {} on channel {}", helloMessage, channel);
 119
 120         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ExceptionHandlingInboundChannelHandler());
 121
 122         sendMessage(helloMessage);
 123
 124         replaceHelloMessageOutboundHandler();
 125         changeState(State.OPEN_WAIT);
 126
 127         timeout = this.timer.newTimeout(new TimerTask() {
 128             @Override
 129             @SuppressWarnings("checkstyle:hiddenField")
 130             public void run(final Timeout timeout) {
 131                 synchronized (this) {
 132                     if (state != State.ESTABLISHED) {
 133
 134                         LOG.debug("Connection timeout after {}, session is in state {}", timeout, state);
 135
 136                         // Do not fail negotiation if promise is done or canceled
 137                         // It would result in setting result of the promise second time and that throws exception
 138                         if (!isPromiseFinished()) {
 139                             LOG.warn("Netconf session was not established after {}", connectionTimeoutMillis);
 140                             changeState(State.FAILED);
 141
 142                             channel.close().addListener(new GenericFutureListener<ChannelFuture>() {
 143                                 @Override
 144                                 public void operationComplete(final ChannelFuture future) throws Exception {
 145                                     if (future.isSuccess()) {
 146                                         LOG.debug("Channel {} closed: success", future.channel());
 147                                     } else {
 148                                         LOG.warn("Channel {} closed: fail", future.channel());
 149                                     }
 150                                 }
 151                             });
 152                         }
 153                     } else if (channel.isOpen()) {
 154                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 155                     }
 156                 }
 157             }
 158
 159             private boolean isPromiseFinished() {
 160                 return promise.isDone() || promise.isCancelled();
 161             }
 162
 163         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 164     }
 165
 166     private void cancelTimeout() {
 167         if (timeout != null) {
 168             timeout.cancel();
 169         }
 170     }
 171
 172     protected final S getSessionForHelloMessage(final NetconfHelloMessage netconfMessage)
 173             throws NetconfDocumentedException {
 174         Preconditions.checkNotNull(netconfMessage, "netconfMessage");
 175
 176         final Document doc = netconfMessage.getDocument();
 177
 178         if (shouldUseChunkFraming(doc)) {
 179             insertChunkFramingToPipeline();
 180         }
 181
 182         changeState(State.ESTABLISHED);
 183         return getSession(sessionListener, channel, netconfMessage);
 184     }
 185
 186     /**
 187      * Insert chunk framing handlers into the pipeline.
 188      */
 189     private void insertChunkFramingToPipeline() {
 190         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
 191                 FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 192         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 193                 new NetconfChunkAggregator());
 194     }
 195
 196     private boolean shouldUseChunkFraming(final Document doc) {
 197         return containsBase11Capability(doc)
 198                 && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
 199     }
 200
 201     /**
 202      * Remove special inbound handler for hello message. Insert regular netconf xml message (en|de)coders.
 203      *
 204      * <p>
 205      * Inbound hello message handler should be kept until negotiation is successful
 206      * It caches any non-hello messages while negotiation is still in progress
 207      */
 208     protected final void replaceHelloMessageInboundHandler(final S session) {
 209         ChannelHandler helloMessageHandler = replaceChannelHandler(channel,
 210                 AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
 211
 212         Preconditions.checkState(helloMessageHandler instanceof NetconfXMLToHelloMessageDecoder,
 213                 "Pipeline handlers misplaced on session: %s, pipeline: %s", session, channel.pipeline());
 214         Iterable<NetconfMessage> netconfMessagesFromNegotiation =
 215                 ((NetconfXMLToHelloMessageDecoder) helloMessageHandler).getPostHelloNetconfMessages();
 216
 217         // Process messages received during negotiation
 218         // The hello message handler does not have to be synchronized,
 219         // since it is always call from the same thread by netty.
 220         // It means, we are now using the thread now
 221         for (NetconfMessage message : netconfMessagesFromNegotiation) {
 222             session.handleMessage(message);
 223         }
 224     }
 225
 226     /**
 227      * Remove special outbound handler for hello message. Insert regular netconf xml message (en|de)coders.
 228      */
 229     private void replaceHelloMessageOutboundHandler() {
 230         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER,
 231                 new NetconfMessageToXMLEncoder());
 232     }
 233
 234     private static ChannelHandler replaceChannelHandler(final Channel channel, final String handlerKey,
 235                                                         final ChannelHandler decoder) {
 236         return channel.pipeline().replace(handlerKey, handlerKey, decoder);
 237     }
 238
 239     @SuppressWarnings("checkstyle:hiddenField")
 240     protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message)
 241             throws NetconfDocumentedException;
 242
 243     private synchronized void changeState(final State newState) {
 244         LOG.debug("Changing state from : {} to : {} for channel: {}", state, newState, channel);
 245         Preconditions.checkState(isStateChangePermitted(state, newState),
 246                 "Cannot change state from %s to %s for chanel %s", state, newState, channel);
 247         this.state = newState;
 248     }
 249
 250     private static boolean containsBase11Capability(final Document doc) {
 251         final NodeList nList = doc.getElementsByTagName(XmlNetconfConstants.CAPABILITY);
 252         for (int i = 0; i < nList.getLength(); i++) {
 253             if (nList.item(i).getTextContent().contains(XmlNetconfConstants.URN_IETF_PARAMS_NETCONF_BASE_1_1)) {
 254                 return true;
 255             }
 256         }
 257         return false;
 258     }
 259
 260     private static boolean isStateChangePermitted(final State state, final State newState) {
 261         if (state == State.IDLE && newState == State.OPEN_WAIT) {
 262             return true;
 263         }
 264         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED) {
 265             return true;
 266         }
 267         if (state == State.OPEN_WAIT && newState == State.FAILED) {
 268             return true;
 269         }
 270         LOG.debug("Transition from {} to {} is not allowed", state, newState);
 271         return false;
 272     }
 273
 274     /**
 275      * Handler to catch exceptions in pipeline during negotiation.
 276      */
 277     private final class ExceptionHandlingInboundChannelHandler extends ChannelInboundHandlerAdapter {
 278         @Override
 279         public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 280             LOG.warn("An exception occurred during negotiation with {}", channel.remoteAddress(), cause);
 281             cancelTimeout();
 282             negotiationFailed(cause);
 283             changeState(State.FAILED);
 284         }
 285     }
 286 }