/*

 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.management.jdp;

import java.io.IOException;

import java.net.Inet6Address;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.NetworkInterface;

import java.net.ProtocolFamily;

import java.net.StandardProtocolFamily;

import java.net.StandardSocketOptions;

import java.nio.ByteBuffer;

import java.nio.channels.DatagramChannel;

import java.nio.channels.UnsupportedAddressTypeException;

import java.util.Enumeration;

/**

 * JdpBroadcaster is responsible for sending pre-built JDP packet across a Net

 *

 * <p> Multicast group address, port number and ttl have to be chosen on upper

 * level and passed to broadcaster constructor. Also it's possible to specify

 * source address to broadcast from. </p>

 *

 * <p>JdpBradcaster doesn't perform any validation on a supplied {@code port} and {@code ttl} because

 * the allowed values depend on an operating system setup</p>

 *

 */

public final class JdpBroadcaster {

    private final InetAddress addr;

    private final int port;

    private final DatagramChannel channel;

    /**

     * Create a new broadcaster

     *

     * @param address - multicast group address

     * @param srcAddress - address of interface we should use to broadcast.

     * @param port - udp port to use

     * @param ttl - packet ttl

     * @throws IOException

     */

    public JdpBroadcaster(InetAddress address, InetAddress srcAddress, int port, int ttl)

            throws IOException, JdpException {

        this.addr = address;

        this.port = port;

        ProtocolFamily family = (address instanceof Inet6Address)

                ? StandardProtocolFamily.INET6 : StandardProtocolFamily.INET;

        channel = DatagramChannel.open(family);

        channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);

        channel.setOption(StandardSocketOptions.IP_MULTICAST_TTL, ttl);

        // with srcAddress equal to null, this constructor do exactly the same as

        // if srcAddress is not passed

        if (srcAddress != null) {

            // User requests particular interface to bind to

            NetworkInterface interf = NetworkInterface.getByInetAddress(srcAddress);

            if (interf == null) {

                throw new JdpException("Unable to get network interface for " + srcAddress.toString());

            }

            if (!interf.isUp()) {

                throw new JdpException(interf.getName() + " is not up.");

            }

            if (!interf.supportsMulticast()) {

                throw new JdpException(interf.getName() + " does not support multicast.");

            }

            try {

                channel.bind(new InetSocketAddress(srcAddress, 0));

            } catch (UnsupportedAddressTypeException ex) {

                throw new JdpException("Unable to bind to source address");

            }

            channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);

        }

    }

    /**

     * Create a new broadcaster

     *

     * @param address - multicast group address

     * @param port - udp port to use

     * @param ttl - packet ttl

     * @throws IOException

     */

    public JdpBroadcaster(InetAddress address, int port, int ttl)

            throws IOException, JdpException {

        this(address, null, port, ttl);

    }

    /**

     * Broadcast pre-built packet

     *

     * @param packet - instance of JdpPacket

     * @throws IOException

     */

    public void sendPacket(JdpPacket packet)

            throws IOException {

        byte[] data = packet.getPacketData();

        // Unlike allocate/put wrap don't need a flip afterward

        ByteBuffer b = ByteBuffer.wrap(data);

        channel.send(b, new InetSocketAddress(addr, port));

    }

    /**

     * Shutdown broadcaster and close underlying socket channel

     *

     * @throws IOException

     */

    public void shutdown() throws IOException {

        channel.close();

    }

}