/*
 * Copyright 2014 Open Networking Laboratory
 *
 * 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.onosproject.proxyndp;

import static org.slf4j.LoggerFactory.getLogger;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.onlab.packet.Ethernet;
import org.onlab.packet.IPv6;
import org.onlab.packet.ICMP6;
import org.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
import org.onosproject.net.flow.DefaultTrafficSelector;
import org.onosproject.net.flow.TrafficSelector;
import org.onosproject.net.packet.PacketContext;
import org.onosproject.net.packet.PacketPriority;
import org.onosproject.net.packet.PacketProcessor;
import org.onosproject.net.packet.PacketService;
import org.onosproject.net.proxyarp.ProxyArpService;
import org.slf4j.Logger;

/**
 * Sample reactive proxy ndp application.
 */
@Component(immediate = true)
public class ProxyNdp {

    private final Logger log = getLogger(getClass());

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected PacketService packetService;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected ProxyArpService proxyArpService;

    private ProxyNdpProcessor processor = new ProxyNdpProcessor();

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected CoreService coreService;

    private ApplicationId appId;

    @Activate
    public void activate() {
        appId = coreService.registerApplication("org.onosproject.proxyndp");
        packetService.addProcessor(processor, PacketProcessor.ADVISOR_MAX + 1);

        TrafficSelector.Builder selectorBuilder = DefaultTrafficSelector.builder();
        selectorBuilder.matchEthType(Ethernet.TYPE_IPV6);
        selectorBuilder.matchIPProtocol(IPv6.PROTOCOL_ICMP6);
        selectorBuilder.matchIcmpv6Type(ICMP6.NEIGHBOR_SOLICITATION);
        packetService.requestPackets(selectorBuilder.build(),
                                     PacketPriority.CONTROL, appId);

        selectorBuilder = DefaultTrafficSelector.builder();
        selectorBuilder.matchEthType(Ethernet.TYPE_IPV6);
        selectorBuilder.matchIPProtocol(IPv6.PROTOCOL_ICMP6);
        selectorBuilder.matchIcmpv6Type(ICMP6.NEIGHBOR_ADVERTISEMENT);
        packetService.requestPackets(selectorBuilder.build(),
                                     PacketPriority.CONTROL, appId);

        log.info("Started with Application ID {}", appId.id());
    }

    @Deactivate
    public void deactivate() {
        packetService.removeProcessor(processor);
        processor = null;
        log.info("Stopped");
    }


    /**
     * Packet processor responsible for forwarding packets along their paths.
     */
    private class ProxyNdpProcessor implements PacketProcessor {

        @Override
        public void process(PacketContext context) {
            // Stop processing if the packet has been handled, since we
            // can't do any more to it.
            if (context.isHandled()) {
                return;
            }

            // Handle the neighbor discovery packet.
            proxyArpService.handlePacket(context);
        }
    }
}