HandshakeTimeoutHandler.java

/*
 * Copyright (c) 2011,2013 Big Switch Networks, Inc.
 *
 * Licensed under the Eclipse Public License, Version 1.0 (the
 * "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 *
 *      http://www.eclipse.org/legal/epl-v10.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 *    Originally created by David Erickson, Stanford University 
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the
 *    License. You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing,
 *    software distributed under the License is distributed on an "AS
 *    IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 *    express or implied. See the License for the specific language
 *    governing permissions and limitations under the License. 
 */

package org.sdnplatform.core.internal;

import java.util.concurrent.TimeUnit;


import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.util.ExternalResourceReleasable;
import org.jboss.netty.util.Timeout;
import org.jboss.netty.util.Timer;
import org.jboss.netty.util.TimerTask;
import org.sdnplatform.core.internal.OFChannelState.HandshakeState;

/**
 * Trigger a timeout if a switch fails to complete handshake soon enough
 */
public class HandshakeTimeoutHandler 
    extends SimpleChannelUpstreamHandler
    implements ExternalResourceReleasable {
    static final HandshakeTimeoutException EXCEPTION = 
            new HandshakeTimeoutException();
    
    final OFChannelState state;
    final Timer timer;
    final long timeoutNanos;
    volatile Timeout timeout;
    
    public HandshakeTimeoutHandler(OFChannelState state, Timer timer,
                                   long timeoutSeconds) {
        super();
        this.state = state;
        this.timer = timer;
        this.timeoutNanos = TimeUnit.SECONDS.toNanos(timeoutSeconds);

    }
    
    @Override
    public void channelOpen(ChannelHandlerContext ctx, ChannelStateEvent e)
            throws Exception {
        if (timeoutNanos > 0) {
            timeout = timer.newTimeout(new HandshakeTimeoutTask(ctx), 
                                       timeoutNanos, TimeUnit.NANOSECONDS);
        }
        ctx.sendUpstream(e);
    }
    
    @Override
    public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e)
            throws Exception {
        if (timeout != null) {
            timeout.cancel();
            timeout = null;
        }
    }

    @Override
    public void releaseExternalResources() {
        timer.stop();
    }
    
    private final class HandshakeTimeoutTask implements TimerTask {

        private final ChannelHandlerContext ctx;

        HandshakeTimeoutTask(ChannelHandlerContext ctx) {
            this.ctx = ctx;
        }

        @Override
        public void run(Timeout timeout) throws Exception {
            if (timeout.isCancelled()) {
                return;
            }

            if (!ctx.getChannel().isOpen()) {
                return;
            }
            if (!state.hsState.equals(HandshakeState.READY))
                Channels.fireExceptionCaught(ctx, EXCEPTION);
        }
    }
}