core/api/src/main/java/org/onosproject/net/neighbour/DefaultNeighbourMessageHandler.java

/*
 * Copyright 2016-present Open Networking Foundation
 *
 * 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.net.neighbour;

import org.onosproject.net.Host;
import org.onosproject.net.host.HostService;

import java.util.Set;

import static org.onlab.packet.VlanId.vlanId;
import static org.onosproject.net.HostId.hostId;

/**
 * Default neighbour message handler which implements basic proxying on an
 * L2 network (i.e. ProxyArp behaviour).
 */
public class DefaultNeighbourMessageHandler implements NeighbourMessageHandler {
    @Override
    public void handleMessage(NeighbourMessageContext context, HostService hostService) {
        switch (context.type()) {
        case REPLY:
            Host h = hostService.getHost(hostId(context.packet().getDestinationMAC(),
                    vlanId(context.packet().getVlanID())));

            if (h == null) {
                context.flood();
            } else {
                context.forward(h.location());
            }
            break;
        case REQUEST:
            // See if we have the target host in the host store
            Set<Host> hosts = hostService.getHostsByIp(context.target());

            Host dst = null;
            Host src = hostService.getHost(hostId(context.srcMac(), context.vlan()));

            for (Host host : hosts) {
                if (host.vlan().equals(context.vlan())) {
                    dst = host;
                    break;
                }
            }

            if (src != null && dst != null) {
                // We know the target host so we can respond
                context.reply(dst.mac());
                return;
            }

            // The request couldn't be resolved.
            // Flood the request on all ports except the incoming port.
            context.flood();
            break;
        default:
            break;
        }

    }
}