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 com.google.common.base.Optional;
  12 import com.google.common.base.Preconditions;
  13 import io.netty.channel.Channel;
  14 import io.netty.channel.ChannelHandler;
  15 import io.netty.channel.ChannelHandlerContext;
  16 import io.netty.handler.ssl.SslHandler;
  17 import io.netty.util.Timeout;
  18 import io.netty.util.Timer;
  19 import io.netty.util.TimerTask;
  20 import io.netty.util.concurrent.Future;
  21 import io.netty.util.concurrent.GenericFutureListener;
  22 import io.netty.util.concurrent.Promise;
  23 import org.opendaylight.controller.netconf.api.NetconfMessage;
  24 import org.opendaylight.controller.netconf.api.NetconfSession;
  25 import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
  26 import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
  27 import org.opendaylight.controller.netconf.util.handler.NetconfMessageAggregator;
  28 import org.opendaylight.controller.netconf.util.handler.NetconfMessageChunkDecoder;
  29 import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
  30 import org.opendaylight.controller.netconf.util.xml.XmlElement;
  31 import org.opendaylight.controller.netconf.util.xml.XmlNetconfConstants;
  32 import org.opendaylight.controller.netconf.util.xml.XmlUtil;
  33 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  34 import org.opendaylight.protocol.framework.SessionListener;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37 import org.w3c.dom.Document;
  38 import org.w3c.dom.NodeList;
  39
  40 import java.util.concurrent.TimeUnit;
  41
  42 public abstract class AbstractNetconfSessionNegotiator<P extends NetconfSessionPreferences, S extends NetconfSession>
  43         extends AbstractSessionNegotiator<NetconfMessage, S> {
  44
  45     private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
  46     public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
  47
  48     protected final P sessionPreferences;
  49
  50     private final SessionListener sessionListener;
  51     private Timeout timeout;
  52
  53     /**
  54      * Possible states for Finite State Machine
  55      */
  56     private enum State {
  57         IDLE, OPEN_WAIT, FAILED, ESTABLISHED
  58     }
  59
  60     private State state = State.IDLE;
  61     private final Timer timer;
  62     private final long connectionTimeoutMillis;
  63
  64     protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise<S> promise, Channel channel, Timer timer,
  65             SessionListener sessionListener, long connectionTimeoutMillis) {
  66         super(promise, channel);
  67         this.sessionPreferences = sessionPreferences;
  68         this.timer = timer;
  69         this.sessionListener = sessionListener;
  70         this.connectionTimeoutMillis = connectionTimeoutMillis;
  71     }
  72
  73     @Override
  74     protected void startNegotiation() {
  75         final Optional<SslHandler> sslHandler = getSslHandler(channel);
  76         if (sslHandler.isPresent()) {
  77             Future<Channel> future = sslHandler.get().handshakeFuture();
  78             future.addListener(new GenericFutureListener<Future<? super Channel>>() {
  79                 @Override
  80                 public void operationComplete(Future<? super Channel> future) throws Exception {
  81                     Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
  82                     logger.debug("Ssl handshake complete");
  83                     start();
  84                 }
  85             });
  86         } else
  87             start();
  88     }
  89
  90     private static Optional<SslHandler> getSslHandler(Channel channel) {
  91         final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
  92         return sslHandler == null ? Optional.<SslHandler> absent() : Optional.of(sslHandler);
  93     }
  94
  95     private void start() {
  96         final NetconfMessage helloMessage = this.sessionPreferences.getHelloMessage();
  97         logger.debug("Session negotiation started with hello message {}", XmlUtil.toString(helloMessage.getDocument()));
  98
  99         channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ChannelHandler() {
 100             @Override
 101             public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
 102             }
 103
 104             @Override
 105             public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
 106             }
 107
 108             @Override
 109             public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
 110                 logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
 111                 cancelTimeout();
 112                 negotiationFailed(cause);
 113                 changeState(State.FAILED);
 114             }
 115         });
 116
 117         timeout = this.timer.newTimeout(new TimerTask() {
 118             @Override
 119             public void run(final Timeout timeout) throws Exception {
 120                 synchronized (this) {
 121                     if (state != State.ESTABLISHED) {
 122                         logger.debug("Connection timeout after {}", timeout);
 123                         final IllegalStateException cause = new IllegalStateException(
 124                                 "Session was not established after " + timeout);
 125                         negotiationFailed(cause);
 126                         changeState(State.FAILED);
 127                     } else if(channel.isOpen()) {
 128                         channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
 129                     }
 130                 }
 131             }
 132         }, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
 133
 134         sendMessage(helloMessage);
 135         changeState(State.OPEN_WAIT);
 136     }
 137
 138     private void cancelTimeout() {
 139         if(timeout!=null)
 140             timeout.cancel();
 141     }
 142
 143     private void sendMessage(NetconfMessage message) {
 144         this.channel.writeAndFlush(message);
 145     }
 146
 147     @Override
 148     protected void handleMessage(NetconfMessage netconfMessage) {
 149         final Document doc = netconfMessage.getDocument();
 150
 151         if (isHelloMessage(doc)) {
 152             if (containsBase11Capability(doc)
 153                     && containsBase11Capability(sessionPreferences.getHelloMessage().getDocument())) {
 154                 channel.pipeline().replace("frameEncoder", "frameEncoder",
 155                         FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
 156                 channel.pipeline().replace("aggregator", "aggregator",
 157                         new NetconfMessageAggregator(FramingMechanism.CHUNK));
 158                 channel.pipeline().addAfter("aggregator", "chunkDecoder", new NetconfMessageChunkDecoder());
 159             }
 160             changeState(State.ESTABLISHED);
 161             S session = getSession(sessionListener, channel, netconfMessage);
 162             negotiationSuccessful(session);
 163         } else {
 164             final IllegalStateException cause = new IllegalStateException(
 165                     "Received message was not hello as expected, but was " + XmlUtil.toString(doc));
 166             logger.warn("Negotiation of netconf session failed", cause);
 167             negotiationFailed(cause);
 168         }
 169     }
 170
 171     protected abstract S getSession(SessionListener sessionListener, Channel channel, NetconfMessage message);
 172
 173     private boolean isHelloMessage(Document doc) {
 174         try {
 175             XmlElement.fromDomElementWithExpected(doc.getDocumentElement(), "hello",
 176                     XmlNetconfConstants.URN_IETF_PARAMS_XML_NS_NETCONF_BASE_1_0);
 177
 178         } catch (IllegalArgumentException | IllegalStateException e) {
 179             return false;
 180         }
 181         return true;
 182     }
 183
 184     private void changeState(final State newState) {
 185         logger.debug("Changing state from : {} to : {}", state, newState);
 186         Preconditions.checkState(isStateChangePermitted(state, newState), "Cannot change state from %s to %s", state,
 187                 newState);
 188         this.state = newState;
 189     }
 190
 191     private boolean containsBase11Capability(final Document doc) {
 192         final NodeList nList = doc.getElementsByTagName("capability");
 193         for (int i = 0; i < nList.getLength(); i++) {
 194             if (nList.item(i).getTextContent().contains("base:1.1")) {
 195                 return true;
 196             }
 197         }
 198         return false;
 199     }
 200
 201     private static boolean isStateChangePermitted(State state, State newState) {
 202         if (state == State.IDLE && newState == State.OPEN_WAIT)
 203             return true;
 204         if (state == State.OPEN_WAIT && newState == State.ESTABLISHED)
 205             return true;
 206         if (state == State.OPEN_WAIT && newState == State.FAILED)
 207             return true;
 208
 209         return false;
 210     }
 211 }