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 package org.opendaylight.netconf.nettyutil;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  14 import io.netty.channel.Channel;
  15 import io.netty.channel.ChannelFuture;
  16 import io.netty.channel.ChannelHandler;
  17 import io.netty.channel.ChannelHandlerContext;
  18 import io.netty.channel.ChannelInboundHandlerAdapter;
  19 import io.netty.handler.ssl.SslHandler;
  20 import io.netty.util.Timeout;
  21 import io.netty.util.Timer;
  22 import io.netty.util.TimerTask;
  23 import io.netty.util.concurrent.GenericFutureListener;
  24 import io.netty.util.concurrent.Promise;
  25 import java.util.Optional;
  26 import java.util.concurrent.TimeUnit;
  27 import org.opendaylight.netconf.api.NetconfDocumentedException;
  28 import org.opendaylight.netconf.api.NetconfMessage;
  29 import org.opendaylight.netconf.api.NetconfSessionListener;
  30 import org.opendaylight.netconf.api.NetconfSessionPreferences;
  31 import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
  32 import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
  33 import org.opendaylight.netconf.nettyutil.handler.FramingMechanismHandlerFactory;
  34 import org.opendaylight.netconf.nettyutil.handler.NetconfChunkAggregator;
  35 import org.opendaylight.netconf.nettyutil.handler.NetconfMessageToXMLEncoder;
  36 import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToHelloMessageDecoder;
  37 import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToMessageDecoder;
  38 import org.opendaylight.netconf.util.messages.FramingMechanism;
  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 ChannelInboundHandlerAdapter implements NetconfSessionNegotiator<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     protected final Channel channel;
  54
  55     private final Promise<S> promise;
  56     private final L sessionListener;
  57     private Timeout timeout;
  58
  59     /**
  60      * Possible states for Finite State Machine.
  61      */
  62     protected enum State {
  63         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  64     }
  65
  66     private State state = State.IDLE;
  67     private final Timer timer;
  68     private final long connectionTimeoutMillis;
  69
  70     protected AbstractNetconfSessionNegotiator(final P sessionPreferences, final Promise<S> promise,
  71                                                final Channel channel, final Timer timer,
  72                                                final L sessionListener, final long connectionTimeoutMillis) {
  73         this.channel = requireNonNull(channel);
  74         this.promise = requireNonNull(promise);
  75         this.sessionPreferences = sessionPreferences;
  76         this.timer = timer;
  77         this.sessionListener = sessionListener;
  78         this.connectionTimeoutMillis = connectionTimeoutMillis;
  79     }
  80
  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                 sslHandler.get().handshakeFuture().addListener(future -> {
  88                     checkState(future.isSuccess(), "Ssl handshake was not successful");
  89                     LOG.debug("Ssl handshake complete");
  90                     start();
  91                 });
  92             } else {
  93                 start();
  94             }
  95         }
  96     }
  97
  98     protected final synchronized boolean ifNegotiatedAlready() {
  99         // Indicates whether negotiation already started
 100         return this.state != State.IDLE;
 101     }
 102
 103     private static Optional<SslHandler> getSslHandler(final Channel channel) {
 104         return Optional.ofNullable(channel.pipeline().get(SslHandler.class));
 105     }
 106
 107     public P getSessionPreferences() {
 108         return sessionPreferences;
 109     }
 110
 111     private void start() {
 112         final NetconfHelloMessage helloMessage = this.sessionPreferences.getHelloMessage();
 113         LOG.debug("Session negotiation started with hello message {} on channel {}", helloMessage, channel);
 114
 115         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ExceptionHandlingInboundChannelHandler());
 116
 117         sendMessage(helloMessage);
 118
 119         replaceHelloMessageOutboundHandler();
 120         changeState(State.OPEN_WAIT);
 121
 122         timeout = this.timer.newTimeout(new TimerTask() {
 123             @Override
 124             @SuppressWarnings("checkstyle:hiddenField")
 125             public void run(final Timeout timeout) {
 126                 synchronized (this) {
 127                     if (state != State.ESTABLISHED) {
 128
 129                         LOG.debug("Connection timeout after {}, session is in state {}", timeout, state);
 130
 131                         // Do not fail negotiation if promise is done or canceled
 132                         // It would result in setting result of the promise second time and that throws exception
 133                         if (!isPromiseFinished()) {
 134                             LOG.warn("Netconf session was not established after {}", connectionTimeoutMillis);
 135                             changeState(State.FAILED);
 136
 137                             channel.close().addListener((GenericFutureListener<ChannelFuture>) future -> {
 138                                 if (future.isSuccess()) {
 139                                     LOG.debug("Channel {} closed: success", future.channel());
 140                                 } else {
 141                                     LOG.warn("Channel {} closed: fail", future.channel());
 142                                 }
 143                             });
 144                         }
 145                     } else if (channel.isOpen()) {
 146                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 147                     }
 148                 }
 149             }
 150
 151             private boolean isPromiseFinished() {
 152                 return promise.isDone() || promise.isCancelled();
 153             }
 154
 155         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 156     }
 157
 158     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 159             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 160     private void cancelTimeout() {
 161         if (timeout != null) {
 162             timeout.cancel();
 163         }
 164     }
 165
 166     protected final S getSessionForHelloMessage(final NetconfHelloMessage netconfMessage)
 167             throws NetconfDocumentedException {
 168         final Document doc = netconfMessage.getDocument();
 169
 170         if (shouldUseChunkFraming(doc)) {
 171             insertChunkFramingToPipeline();
 172         }
 173
 174         changeState(State.ESTABLISHED);
 175         return getSession(sessionListener, channel, netconfMessage);
 176     }
 177
 178     /**
 179      * Insert chunk framing handlers into the pipeline.
 180      */
 181     private void insertChunkFramingToPipeline() {
 182         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
 183                 FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 184         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
 185                 new NetconfChunkAggregator());
 186     }
 187
 188     private boolean shouldUseChunkFraming(final Document doc) {
 189         return containsBase11Capability(doc)
 190                 && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
 191     }
 192
 193     /**
 194      * Remove special inbound handler for hello message. Insert regular netconf xml message (en|de)coders.
 195      *
 196      * <p>
 197      * Inbound hello message handler should be kept until negotiation is successful
 198      * It caches any non-hello messages while negotiation is still in progress
 199      */
 200     protected final void replaceHelloMessageInboundHandler(final S session) {
 201         ChannelHandler helloMessageHandler = replaceChannelHandler(channel,
 202                 AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
 203
 204         checkState(helloMessageHandler instanceof NetconfXMLToHelloMessageDecoder,
 205                 "Pipeline handlers misplaced on session: %s, pipeline: %s", session, channel.pipeline());
 206         Iterable<NetconfMessage> netconfMessagesFromNegotiation =
 207                 ((NetconfXMLToHelloMessageDecoder) helloMessageHandler).getPostHelloNetconfMessages();
 208
 209         // Process messages received during negotiation
 210         // The hello message handler does not have to be synchronized,
 211         // since it is always call from the same thread by netty.
 212         // It means, we are now using the thread now
 213         for (NetconfMessage message : netconfMessagesFromNegotiation) {
 214             session.handleMessage(message);
 215         }
 216     }
 217
 218     /**
 219      * Remove special outbound handler for hello message. Insert regular netconf xml message (en|de)coders.
 220      */
 221     private void replaceHelloMessageOutboundHandler() {
 222         replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER,
 223                 new NetconfMessageToXMLEncoder());
 224     }
 225
 226     private static ChannelHandler replaceChannelHandler(final Channel channel, final String handlerKey,
 227                                                         final ChannelHandler decoder) {
 228         return channel.pipeline().replace(handlerKey, handlerKey, decoder);
 229     }
 230
 231     @SuppressWarnings("checkstyle:hiddenField")
 232     protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message)
 233             throws NetconfDocumentedException;
 234
 235     private synchronized void changeState(final State newState) {
 236         LOG.debug("Changing state from : {} to : {} for channel: {}", state, newState, channel);
 237         checkState(isStateChangePermitted(state, newState),
 238                 "Cannot change state from %s to %s for chanel %s", state, newState, channel);
 239         this.state = newState;
 240     }
 241
 242     private static boolean containsBase11Capability(final Document doc) {
 243         final NodeList nList = doc.getElementsByTagNameNS(
 244             XmlNetconfConstants.URN_IETF_PARAMS_XML_NS_NETCONF_BASE_1_0,
 245             XmlNetconfConstants.CAPABILITY);
 246         for (int i = 0; i < nList.getLength(); i++) {
 247             if (nList.item(i).getTextContent().contains(XmlNetconfConstants.URN_IETF_PARAMS_NETCONF_BASE_1_1)) {
 248                 return true;
 249             }
 250         }
 251         return false;
 252     }
 253
 254     private static boolean isStateChangePermitted(final State state, final State newState) {
 255         if (state == State.IDLE && newState == State.OPEN_WAIT) {
 256             return true;
 257         }
 258         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED) {
 259             return true;
 260         }
 261         if (state == State.OPEN_WAIT && newState == State.FAILED) {
 262             return true;
 263         }
 264         LOG.debug("Transition from {} to {} is not allowed", state, newState);
 265         return false;
 266     }
 267
 268     /**
 269      * Handler to catch exceptions in pipeline during negotiation.
 270      */
 271     private final class ExceptionHandlingInboundChannelHandler extends ChannelInboundHandlerAdapter {
 272         @Override
 273         public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 274             LOG.warn("An exception occurred during negotiation with {}", channel.remoteAddress(), cause);
 275             cancelTimeout();
 276             negotiationFailed(cause);
 277             changeState(State.FAILED);
 278         }
 279     }
 280
 281     protected final void negotiationSuccessful(final S session) {
 282         LOG.debug("Negotiation on channel {} successful with session {}", channel, session);
 283         channel.pipeline().replace(this, "session", session);
 284         promise.setSuccess(session);
 285     }
 286
 287     protected void negotiationFailed(final Throwable cause) {
 288         LOG.debug("Negotiation on channel {} failed", channel, cause);
 289         channel.close();
 290         promise.setFailure(cause);
 291     }
 292
 293     /**
 294      * Send a message to peer and fail negotiation if it does not reach
 295      * the peer.
 296      *
 297      * @param msg Message which should be sent.
 298      */
 299     protected final void sendMessage(final NetconfMessage msg) {
 300         this.channel.writeAndFlush(msg).addListener(f -> {
 301             if (!f.isSuccess()) {
 302                 LOG.info("Failed to send message {}", msg, f.cause());
 303                 negotiationFailed(f.cause());
 304             } else {
 305                 LOG.trace("Message {} sent to socket", msg);
 306             }
 307         });
 308     }
 309
 310     @Override
 311     @SuppressWarnings("checkstyle:illegalCatch")
 312     public final void channelActive(final ChannelHandlerContext ctx) {
 313         LOG.debug("Starting session negotiation on channel {}", channel);
 314         try {
 315             startNegotiation();
 316         } catch (final Exception e) {
 317             LOG.warn("Unexpected negotiation failure", e);
 318             negotiationFailed(e);
 319         }
 320     }
 321
 322     @Override
 323     @SuppressWarnings("checkstyle:illegalCatch")
 324     public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
 325         LOG.debug("Negotiation read invoked on channel {}", channel);
 326         try {
 327             handleMessage((NetconfHelloMessage) msg);
 328         } catch (final Exception e) {
 329             LOG.debug("Unexpected error while handling negotiation message {}", msg, e);
 330             negotiationFailed(e);
 331         }
 332     }
 333
 334     @Override
 335     public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
 336         LOG.info("Unexpected error during negotiation", cause);
 337         negotiationFailed(cause);
 338     }
 339
 340     protected abstract void handleMessage(NetconfHelloMessage msg) throws Exception;
 341 }