org.eclipse.scada.protocol.relp.RelpHandler.java Source code

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Here is the source code for org.eclipse.scada.protocol.relp.RelpHandler.java

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/*******************************************************************************
 * Copyright (c) 2014 IBH SYSTEMS GmbH 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
 *
 * Contributors:
 *     IBH SYSTEMS GmbH - initial API and implementation
 *******************************************************************************/
package org.eclipse.scada.protocol.relp;

import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.concurrent.ScheduledFuture;

import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;

import org.eclipse.scada.protocol.relp.data.OpenRequest;
import org.eclipse.scada.protocol.relp.data.ServerCloseMessage;
import org.eclipse.scada.protocol.relp.data.SyslogRequest;
import org.eclipse.scada.protocol.syslog.Constants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class RelpHandler extends ChannelDuplexHandler {
    private final static Logger logger = LoggerFactory.getLogger(RelpHandler.class);

    private boolean opened;

    private final int timeout;

    private ScheduledFuture<?> timeoutTask;

    public RelpHandler() {
        this(Integer.getInteger("org.eclipse.scada.protocol.relp.openTimeout", 20_000));
    }

    public RelpHandler(final int timeout) {
        this.timeout = timeout;
    }

    @Override
    public void channelActive(final ChannelHandlerContext ctx) throws Exception {
        // wait for "open" .. start timeout
        if (this.timeout > 0) {
            logger.debug("Adding timeout: {} seconds", this.timeout);
            this.timeoutTask = ctx.executor().schedule(new Runnable() {

                @Override
                public void run() {
                    processTimeout(ctx);
                }
            }, this.timeout, TimeUnit.MILLISECONDS);
        }
    }

    protected void processTimeout(final ChannelHandlerContext ctx) {
        ctx.writeAndFlush(ServerCloseMessage.INSTANCE);
        ctx.close();
    }

    @Override
    public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
        if (msg instanceof OpenRequest) {
            handleOpen(ctx, (OpenRequest) msg);
        } else if (msg instanceof SyslogRequest) {
            handleSyslog(ctx, (SyslogRequest) msg);
        }
    }

    protected void handleSyslog(final ChannelHandlerContext ctx, final SyslogRequest msg) {
        logger.debug("Process syslog command: {}", msg);
        ctx.fireChannelRead(msg.getData());
        ctx.writeAndFlush(msg.replyOk());
    }

    protected void handleOpen(final ChannelHandlerContext ctx, final OpenRequest msg) {
        if (this.opened) {
            logger.warn("Duplicate open request. Closing channel.");
            ctx.close();
            return;
        }

        this.opened = true;

        logger.debug("Removing timeout");
        if (this.timeoutTask != null) {
            this.timeoutTask.cancel(false);
        }

        logger.debug("Process open command: {}", msg);

        final String cs = msg.getOffers().get(Constants.OFFER_COMMANDS);
        if (cs == null) {
            ctx.write(ServerCloseMessage.INSTANCE);
            throw new IllegalStateException("Offer 'commands' not found in open command");
        }

        final Set<String> commands = new HashSet<>(Arrays.asList(cs.split(",")));

        logger.debug("Supported commands: {}", commands);

        if (!commands.contains("syslog")) {
            ctx.write(ServerCloseMessage.INSTANCE);
            throw new IllegalStateException("Command 'syslog' not supported");
        }

        final Map<String, String> result = new HashMap<>(1);
        result.put(Constants.OFFER_COMMANDS, "syslog");
        result.put(Constants.OFFER_PROTOCOL_VERSION, "0");

        ctx.writeAndFlush(msg.replyOk(result));
        ctx.fireChannelActive();
    }
}