/*
* 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.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.NetconfMessage;
import org.opendaylight.controller.netconf.api.NetconfSession;
import org.opendaylight.controller.netconf.api.NetconfSessionPreferences;
import org.opendaylight.controller.netconf.util.handler.FramingMechanismHandlerFactory;
import org.opendaylight.controller.netconf.util.handler.NetconfMessageAggregator;
import org.opendaylight.controller.netconf.util.handler.NetconfMessageChunkDecoder;
import org.opendaylight.controller.netconf.util.messages.FramingMechanism;
import org.opendaylight.controller.netconf.util.xml.XmlElement;
import org.opendaylight.controller.netconf.util.xml.XmlNetconfConstants;
import org.opendaylight.controller.netconf.util.xml.XmlUtil;
import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
import org.opendaylight.protocol.framework.SessionListener;
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
extends AbstractSessionNegotiator {
// TODO what time ?
private static final long INITIAL_HOLDTIMER = 1;
private static final Logger logger = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
protected final P sessionPreferences;
private final SessionListener sessionListener;
private Timeout timeout;
/**
* Possible states for Finite State Machine
*/
private enum State {
IDLE, OPEN_WAIT, FAILED, ESTABLISHED
}
private State state = State.IDLE;
private final Timer timer;
protected AbstractNetconfSessionNegotiator(P sessionPreferences, Promise promise, Channel channel, Timer timer,
SessionListener sessionListener) {
super(promise, channel);
this.sessionPreferences = sessionPreferences;
this.timer = timer;
this.sessionListener = sessionListener;
}
@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) throws Exception {
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);
}
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 ChannelHandler() {
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
logger.warn("An exception occurred during negotiation on channel {}", channel.localAddress(), cause);
cancelTimeout();
negotiationFailed(cause);
changeState(State.FAILED);
}
});
timeout = this.timer.newTimeout(new TimerTask() {
@Override
public void run(final Timeout timeout) throws Exception {
synchronized (this) {
if (state != State.ESTABLISHED) {
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);
}
}
}
}, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
sendMessage(helloMessage);
changeState(State.OPEN_WAIT);
}
private void cancelTimeout() {
if(timeout!=null)
timeout.cancel();
}
private void sendMessage(NetconfMessage message) {
this.channel.writeAndFlush(message);
}
@Override
protected void handleMessage(NetconfMessage netconfMessage) {
final Document doc = netconfMessage.getDocument();
if (isHelloMessage(doc)) {
if (containsBase11Capability(doc)
&& containsBase11Capability(sessionPreferences.getHelloMessage().getDocument())) {
channel.pipeline().replace("frameEncoder", "frameEncoder",
FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
channel.pipeline().replace("aggregator", "aggregator",
new NetconfMessageAggregator(FramingMechanism.CHUNK));
channel.pipeline().addAfter("aggregator", "chunkDecoder", new NetconfMessageChunkDecoder());
}
changeState(State.ESTABLISHED);
S session = getSession(sessionListener, channel, netconfMessage);
negotiationSuccessful(session);
} else {
final IllegalStateException cause = new IllegalStateException(
"Received message was not hello as expected, but was " + XmlUtil.toString(doc));
logger.warn("Negotiation of netconf session failed", cause);
negotiationFailed(cause);
}
}
protected abstract S getSession(SessionListener sessionListener, Channel channel, NetconfMessage message);
private boolean isHelloMessage(Document doc) {
try {
XmlElement.fromDomElementWithExpected(doc.getDocumentElement(), "hello",
XmlNetconfConstants.URN_IETF_PARAMS_XML_NS_NETCONF_BASE_1_0);
} catch (IllegalArgumentException | IllegalStateException e) {
return false;
}
return true;
}
private 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;
return false;
}
}