/*
* 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.netconf.nettyutil;
import static com.google.common.base.Preconditions.checkState;
import static java.util.Objects.requireNonNull;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
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.concurrent.GenericFutureListener;
import io.netty.util.concurrent.Promise;
import java.util.Optional;
import java.util.concurrent.TimeUnit;
import org.checkerframework.checker.lock.qual.GuardedBy;
import org.opendaylight.netconf.api.NetconfDocumentedException;
import org.opendaylight.netconf.api.NetconfMessage;
import org.opendaylight.netconf.api.NetconfSessionListener;
import org.opendaylight.netconf.api.NetconfSessionPreferences;
import org.opendaylight.netconf.api.messages.NetconfHelloMessage;
import org.opendaylight.netconf.api.xml.XmlNetconfConstants;
import org.opendaylight.netconf.nettyutil.handler.FramingMechanismHandlerFactory;
import org.opendaylight.netconf.nettyutil.handler.NetconfChunkAggregator;
import org.opendaylight.netconf.nettyutil.handler.NetconfMessageToXMLEncoder;
import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToHelloMessageDecoder;
import org.opendaylight.netconf.nettyutil.handler.NetconfXMLToMessageDecoder;
import org.opendaylight.netconf.util.messages.FramingMechanism;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
public abstract class AbstractNetconfSessionNegotiator
, L extends NetconfSessionListener>
extends ChannelInboundHandlerAdapter implements NetconfSessionNegotiator {
/**
* Possible states for Finite State Machine.
*/
protected enum State {
IDLE, OPEN_WAIT, FAILED, ESTABLISHED
}
private static final Logger LOG = LoggerFactory.getLogger(AbstractNetconfSessionNegotiator.class);
public static final String NAME_OF_EXCEPTION_HANDLER = "lastExceptionHandler";
protected final P sessionPreferences;
protected final Channel channel;
private final long connectionTimeoutMillis;
private final Promise promise;
private final L sessionListener;
private final Timer timer;
private Timeout timeoutTask;
@GuardedBy("this")
private State state = State.IDLE;
protected AbstractNetconfSessionNegotiator(final P sessionPreferences, final Promise promise,
final Channel channel, final Timer timer,
final L sessionListener, final long connectionTimeoutMillis) {
this.channel = requireNonNull(channel);
this.promise = requireNonNull(promise);
this.sessionPreferences = sessionPreferences;
this.timer = timer;
this.sessionListener = sessionListener;
this.connectionTimeoutMillis = connectionTimeoutMillis;
}
protected final void startNegotiation() {
if (ifNegotiatedAlready()) {
LOG.debug("Negotiation on channel {} already started", channel);
} else {
final Optional sslHandler = getSslHandler(channel);
if (sslHandler.isPresent()) {
sslHandler.get().handshakeFuture().addListener(future -> {
checkState(future.isSuccess(), "Ssl handshake was not successful");
LOG.debug("Ssl handshake complete");
start();
});
} else {
start();
}
}
}
protected final synchronized boolean ifNegotiatedAlready() {
// Indicates whether negotiation already started
return this.state != State.IDLE;
}
private static Optional getSslHandler(final Channel channel) {
return Optional.ofNullable(channel.pipeline().get(SslHandler.class));
}
public P getSessionPreferences() {
return sessionPreferences;
}
private void start() {
final NetconfHelloMessage helloMessage = this.sessionPreferences.getHelloMessage();
LOG.debug("Session negotiation started with hello message {} on channel {}", helloMessage, channel);
channel.pipeline().addLast(NAME_OF_EXCEPTION_HANDLER, new ExceptionHandlingInboundChannelHandler());
sendMessage(helloMessage);
replaceHelloMessageOutboundHandler();
changeState(State.OPEN_WAIT);
timeoutTask = this.timer.newTimeout(this::timeoutExpired, connectionTimeoutMillis, TimeUnit.MILLISECONDS);
}
private synchronized void timeoutExpired(final Timeout timeout) {
if (state != State.ESTABLISHED) {
LOG.debug("Connection timeout after {}, session backed by channel {} is in state {}", timeout, channel,
state);
// Do not fail negotiation if promise is done or canceled
// It would result in setting result of the promise second time and that throws exception
if (!promise.isDone() && !promise.isCancelled()) {
LOG.warn("Netconf session backed by channel {} was not established after {}", channel,
connectionTimeoutMillis);
changeState(State.FAILED);
channel.close().addListener((GenericFutureListener) future -> {
if (future.isSuccess()) {
LOG.debug("Channel {} closed: success", future.channel());
} else {
LOG.warn("Channel {} closed: fail", future.channel());
}
});
}
} else if (channel.isOpen()) {
channel.pipeline().remove(NAME_OF_EXCEPTION_HANDLER);
}
}
private void cancelTimeout() {
if (timeoutTask != null) {
timeoutTask.cancel();
}
}
protected final S getSessionForHelloMessage(final NetconfHelloMessage netconfMessage)
throws NetconfDocumentedException {
final Document doc = netconfMessage.getDocument();
if (shouldUseChunkFraming(doc)) {
insertChunkFramingToPipeline();
}
changeState(State.ESTABLISHED);
return getSession(sessionListener, channel, netconfMessage);
}
/**
* Insert chunk framing handlers into the pipeline.
*/
private void insertChunkFramingToPipeline() {
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_FRAME_ENCODER,
FramingMechanismHandlerFactory.createHandler(FramingMechanism.CHUNK));
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_AGGREGATOR,
new NetconfChunkAggregator());
}
private boolean shouldUseChunkFraming(final Document doc) {
return containsBase11Capability(doc)
&& containsBase11Capability(sessionPreferences.getHelloMessage().getDocument());
}
/**
* Remove special inbound handler for hello message. Insert regular netconf xml message (en|de)coders.
*
*
* Inbound hello message handler should be kept until negotiation is successful
* It caches any non-hello messages while negotiation is still in progress
*/
protected final void replaceHelloMessageInboundHandler(final S session) {
ChannelHandler helloMessageHandler = replaceChannelHandler(channel,
AbstractChannelInitializer.NETCONF_MESSAGE_DECODER, new NetconfXMLToMessageDecoder());
checkState(helloMessageHandler instanceof NetconfXMLToHelloMessageDecoder,
"Pipeline handlers misplaced on session: %s, pipeline: %s", session, channel.pipeline());
Iterable netconfMessagesFromNegotiation =
((NetconfXMLToHelloMessageDecoder) helloMessageHandler).getPostHelloNetconfMessages();
// Process messages received during negotiation
// The hello message handler does not have to be synchronized,
// since it is always call from the same thread by netty.
// It means, we are now using the thread now
for (NetconfMessage message : netconfMessagesFromNegotiation) {
session.handleMessage(message);
}
}
/**
* Remove special outbound handler for hello message. Insert regular netconf xml message (en|de)coders.
*/
private void replaceHelloMessageOutboundHandler() {
replaceChannelHandler(channel, AbstractChannelInitializer.NETCONF_MESSAGE_ENCODER,
new NetconfMessageToXMLEncoder());
}
private static ChannelHandler replaceChannelHandler(final Channel channel, final String handlerKey,
final ChannelHandler decoder) {
return channel.pipeline().replace(handlerKey, handlerKey, decoder);
}
@SuppressWarnings("checkstyle:hiddenField")
protected abstract S getSession(L sessionListener, Channel channel, NetconfHelloMessage message)
throws NetconfDocumentedException;
private synchronized void changeState(final State newState) {
LOG.debug("Changing state from : {} to : {} for channel: {}", state, newState, channel);
checkState(isStateChangePermitted(state, newState),
"Cannot change state from %s to %s for channel %s", state, newState, channel);
this.state = newState;
}
private static boolean containsBase11Capability(final Document doc) {
final NodeList nList = doc.getElementsByTagNameNS(
XmlNetconfConstants.URN_IETF_PARAMS_XML_NS_NETCONF_BASE_1_0,
XmlNetconfConstants.CAPABILITY);
for (int i = 0; i < nList.getLength(); i++) {
if (nList.item(i).getTextContent().contains(XmlNetconfConstants.URN_IETF_PARAMS_NETCONF_BASE_1_1)) {
return true;
}
}
return false;
}
private static boolean isStateChangePermitted(final State state, final 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;
}
LOG.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(final ChannelHandlerContext ctx, final Throwable cause) {
LOG.warn("An exception occurred during negotiation with {} on channel {}",
channel.remoteAddress(), channel, cause);
// FIXME: this is quite suspect as it is competing with timeoutExpired() without synchronization
cancelTimeout();
negotiationFailed(cause);
changeState(State.FAILED);
}
}
protected final void negotiationSuccessful(final S session) {
LOG.debug("Negotiation on channel {} successful with session {}", channel, session);
channel.pipeline().replace(this, "session", session);
promise.setSuccess(session);
}
protected void negotiationFailed(final Throwable cause) {
LOG.debug("Negotiation on channel {} failed", channel, cause);
channel.close();
promise.setFailure(cause);
}
/**
* Send a message to peer and fail negotiation if it does not reach
* the peer.
*
* @param msg Message which should be sent.
*/
protected final void sendMessage(final NetconfMessage msg) {
this.channel.writeAndFlush(msg).addListener(f -> {
if (!f.isSuccess()) {
LOG.info("Failed to send message {} on channel {}", msg, channel, f.cause());
negotiationFailed(f.cause());
} else {
LOG.trace("Message {} sent to socket on channel {}", msg, channel);
}
});
}
@Override
@SuppressWarnings("checkstyle:illegalCatch")
public final void channelActive(final ChannelHandlerContext ctx) {
LOG.debug("Starting session negotiation on channel {}", channel);
try {
startNegotiation();
} catch (final Exception e) {
LOG.warn("Unexpected negotiation failure on channel {}", channel, e);
negotiationFailed(e);
}
}
@Override
@SuppressWarnings("checkstyle:illegalCatch")
public final void channelRead(final ChannelHandlerContext ctx, final Object msg) {
LOG.debug("Negotiation read invoked on channel {}", channel);
try {
handleMessage((NetconfHelloMessage) msg);
} catch (final Exception e) {
LOG.debug("Unexpected error while handling negotiation message {} on channel {}", msg, channel, e);
negotiationFailed(e);
}
}
@Override
public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
LOG.info("Unexpected error during negotiation on channel {}", channel, cause);
negotiationFailed(cause);
}
protected abstract void handleMessage(NetconfHelloMessage msg) throws Exception;
}