/*
* Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.netconf.util;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.ssl.SslHandler;
import io.netty.util.Timeout;
import io.netty.util.Timer;
import io.netty.util.TimerTask;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.GenericFutureListener;
import io.netty.util.concurrent.Promise;
import org.opendaylight.controller.netconf.api.NetconfDocumentedException;
import org.opendaylight.controller.netconf.api.NetconfMessage;
import org.opendaylight.controller.netconf.api.NetconfSessionListener;
import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
import org.opendaylight.controller.netconf.util.handler.NetconfChunkAggregator;
import org.opendaylight.controller.netconf.util.handler.NetconfMessageToXMLEncoder;
import org.opendaylight.controller.netconf.util.handler.NetconfXMLToMessageDecoder;
import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
import org.opendaylight.controller.netconf.util.messages.NetconfHelloMessage;
import org.opendaylight.controller.netconf.util.xml.XmlUtil;
import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import java.util.concurrent.TimeUnit;
public abstract class AbstractNetconfSessionNegotiator
, L extends NetconfSessionListener>
extends AbstractSessionNegotiator {
private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
protected final P sessionPreferences;
private final L sessionListener;
private Timeout timeout;
/**
* Possible states for Finite State Machine
*/
protected enum State {
IDLE, OPEN_WAIT, FAILED, ESTABLISHED
}
private State state = State.IDLE;
private final Timer timer;
private final long connectionTimeoutMillis;
// TODO shrink constructor
protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise promise, Channel channel, Timer timer,
L sessionListener, long connectionTimeoutMillis) {
super(promise, channel);
this.sessionPreferences = sessionPreferences;
this.timer = timer;
this.sessionListener = sessionListener;
this.connectionTimeoutMillis = connectionTimeoutMillis;
}
@Override
protected void startNegotiation() {
final Optional sslHandler = getSslHandler(channel);
if (sslHandler.isPresent()) {
Future future = sslHandler.get().handshakeFuture();
future.addListener(new GenericFutureListener>() {
@Override
public void operationComplete(Future super Channel> future) {
Preconditions.checkState(future.isSuccess(), "Ssl handshake was not successful");
logger.debug("Ssl handshake complete");
start();
}
});
} else {
start();
}
}
private static Optional getSslHandler(Channel channel) {
final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
return sslHandler == null ? Optional. absent() : Optional.of(sslHandler);
}
public P getSessionPreferences() {
return sessionPreferences;
}
private void start() {
final NetconfMessage helloMessage = this.sessionPreferences.getHelloMessage();
logger.debug("Session negotiation started with hello message {}", XmlUtil.toString(helloMessage.getDocument()));
channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ExceptionHandlingInboundChannelHandler());
timeout = this.timer.newTimeout(new TimerTask() {
@Override
public void run(final Timeout timeout) {
synchronized (this) {
if (state != State.ESTABLISHED) {
logger.debug("Connection timeout after {}, session is in state {}", timeout, state);
final IllegalStateException cause = new IllegalStateException(
"Session was not established after " + timeout);
negotiationFailed(cause);
changeState(State.FAILED);
} else if(channel.isOpen()) {
channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
}
}
}
}, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
// FIXME, make sessionPreferences return HelloMessage, move NetconfHelloMessage to API
sendMessage((NetconfHelloMessage)helloMessage);
changeState(State.OPEN_WAIT);
}
private void cancelTimeout() {
if(timeout!=null) {
timeout.cancel();
}
}
@Override
protected void handleMessage(NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
S session = getSessionForHelloMessage(netconfMessage) ;
negotiationSuccessful(session);
}
protected final S getSessionForHelloMessage(NetconfHelloMessage netconfMessage) throws NetconfDocumentedException {
Preconditions.checkNotNull(netconfMessage, "netconfMessage");
final Document doc = netconfMessage.getDocument();
replaceHelloMessageHandlers();
if (shouldUseChunkFraming(doc)) {
insertChunkFramingToPipeline();
}
changeState(State.ESTABLISHED);
return getSession(sessionListener, channel, netconfMessage);
}
/**
* Insert chunk framing handlers into the pipeline
*/
protected void insertChunkFramingToPipeline() {
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
new NetconfChunkAggregator());
}
protected boolean shouldUseChunkFraming(Document doc) {
return containsBase11Capability(doc)
&& containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
}
/**
* Remove special handlers for hello message. Insert regular netconf xml message (en|de)coders.
*/
protected void replaceHelloMessageHandlers() {
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER, new NetconfMessageToXMLEncoder());
}
private static ChannelHandler replaceChannelHandler(Channel channel, String handlerKey, ChannelHandler decoder) {
return channel.pipeline().replace(handlerKey, handlerKey, decoder);
}
protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message) throws NetconfDocumentedException;
protected synchronized void changeState(final State newState) {
logger.debug("Changing state from : {} to : {}", state, newState);
Preconditions.checkState(isStateChangePermitted(state, newState), "Cannot change state from %s to %s", state,
newState);
this.state = newState;
}
private boolean containsBase11Capability(final Document doc) {
final NodeList nList = doc.getElementsByTagName("capability");
for (int i = 0; i < nList.getLength(); i++) {
if (nList.item(i).getTextContent().contains("base:1.1")) {
return true;
}
}
return false;
}
private static boolean isStateChangePermitted(State state, State newState) {
if (state == State.IDLE && newState == State.OPEN_WAIT) {
return true;
}
if (state == State.OPEN_WAIT && newState == State.ESTABLISHED) {
return true;
}
if (state == State.OPEN_WAIT && newState == State.FAILED) {
return true;
}
logger.debug("Transition from {} to {} is not allowed", state, newState);
return false;
}
/**
* Handler to catch exceptions in pipeline during negotiation
*/
private final class ExceptionHandlingInboundChannelHandler extends ChannelInboundHandlerAdapter {
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
cancelTimeout();
negotiationFailed(cause);
changeState(State.FAILED);
}
}
}