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 org.opendaylight.controller.netconf.api.AbstractNetconfSession;
  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.NetconfMessageAggregator;
  30 import org.opendaylight.controller.netconf.util.handler.NetconfMessageChunkDecoder;
  31 import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
  32 import org.opendaylight.controller.netconf.util.xml.XmlElement;
  33 import org.opendaylight.controller.netconf.util.xml.XmlNetconfConstants;
  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 com.google.common.base.Optional;
  42 import com.google.common.base.Preconditions;
  43
  44 public abstract class AbstractNetconfSessionNegotiator<P extends NetconfSessionPreferences, S extends AbstractNetconfSession<S, L>, L extends NetconfSessionListener<S>>
  45 extends AbstractSessionNegotiator<NetconfMessage, S> {
  46
  47     private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
  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     private 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     protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise<S> promise, Channel channel, Timer timer,
  67             L sessionListener, long connectionTimeoutMillis) {
  68         super(promise, channel);
  69         this.sessionPreferences = sessionPreferences;
  70         this.timer = timer;
  71         this.sessionListener = sessionListener;
  72         this.connectionTimeoutMillis = connectionTimeoutMillis;
  73     }
  74
  75     @Override
  76     protected void startNegotiation() {
  77         final Optional<SslHandler> sslHandler = getSslHandler(channel);
  78         if (sslHandler.isPresent()) {
  79             Future<Channel> future = sslHandler.get().handshakeFuture();
  80             future.addListener(new GenericFutureListener<Future<? super Channel>>() {
  81                 @Override
  82                 public void operationComplete(Future<? super Channel> future) throws Exception {
  83                     Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
  84                     logger.debug("Ssl handshake complete");
  85                     start();
  86                 }
  87             });
  88         } else
  89             start();
  90     }
  91
  92     private static Optional<SslHandler> getSslHandler(Channel channel) {
  93         final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
  94         return sslHandler == null ? Optional.<SslHandler> absent() : Optional.of(sslHandler);
  95     }
  96
  97     private void start() {
  98         final NetconfMessage helloMessage = this.sessionPreferences.getHelloMessage();
  99         logger.debug("Session negotiation started with hello message {}", XmlUtil.toString(helloMessage.getDocument()));
 100
 101         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ChannelHandler() {
 102             @Override
 103             public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
 104             }
 105
 106             @Override
 107             public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
 108             }
 109
 110             @Override
 111             public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
 112                 logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
 113                 cancelTimeout();
 114                 negotiationFailed(cause);
 115                 changeState(State.FAILED);
 116             }
 117         });
 118
 119         timeout = this.timer.newTimeout(new TimerTask() {
 120             @Override
 121             public void run(final Timeout timeout) throws Exception {
 122                 synchronized (this) {
 123                     if (state != State.ESTABLISHED) {
 124                         logger.debug("Connection timeout after {}, session is in state {}", timeout, state);
 125                         final IllegalStateException cause = new IllegalStateException(
 126                                 "Session was not established after " + timeout);
 127                         negotiationFailed(cause);
 128                         changeState(State.FAILED);
 129                     } else if(channel.isOpen()) {
 130                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 131                     }
 132                 }
 133             }
 134         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 135
 136         sendMessage(helloMessage);
 137         changeState(State.OPEN_WAIT);
 138     }
 139
 140     private void cancelTimeout() {
 141         if(timeout!=null)
 142             timeout.cancel();
 143     }
 144
 145     private void sendMessage(NetconfMessage message) {
 146         this.channel.writeAndFlush(message);
 147     }
 148
 149     @Override
 150     protected void handleMessage(NetconfMessage netconfMessage) {
 151         final Document doc = netconfMessage.getDocument();
 152
 153         if (isHelloMessage(doc)) {
 154             if (containsBase11Capability(doc)
 155                     && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument())) {
 156                 channel.pipeline().replace("frameEncoder", "frameEncoder",
 157                         FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 158                 channel.pipeline().replace("aggregator", "aggregator",
 159                         new NetconfMessageAggregator(FramingMechanism.CHUNK));
 160                 channel.pipeline().addAfter("aggregator", "chunkDecoder", new NetconfMessageChunkDecoder());
 161             }
 162             changeState(State.ESTABLISHED);
 163             S session = getSession(sessionListener, channel, netconfMessage);
 164             negotiationSuccessful(session);
 165         } else {
 166             final IllegalStateException cause = new IllegalStateException(
 167                     "Received message was not hello as expected, but was " + XmlUtil.toString(doc));
 168             logger.warn("Negotiation of netconf session failed", cause);
 169             negotiationFailed(cause);
 170         }
 171     }
 172
 173     protected abstract S getSession(L sessionListener, Channel channel, NetconfMessage message);
 174
 175     private boolean isHelloMessage(Document doc) {
 176         try {
 177             XmlElement.fromDomElementWithExpected(doc.getDocumentElement(), "hello",
 178                     XmlNetconfConstants.URN_IETF_PARAMS_XML_NS_NETCONF_BASE_1_0);
 179
 180         } catch (IllegalArgumentException | IllegalStateException e) {
 181             return false;
 182         }
 183         return true;
 184     }
 185
 186     private 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         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED)
 207             return true;
 208         if (state == State.OPEN_WAIT && newState == State.FAILED)
 209             return true;
 210
 211         logger.debug("Transition from {} to {} is not allowed", state, newState);
 212         return false;
 213     }
 214 }