1/*
2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25package sun.management.jdp;
26
27import java.io.IOException;
28import java.net.Inet6Address;
29import java.net.InetAddress;
30import java.net.InetSocketAddress;
31import java.net.NetworkInterface;
32import java.net.ProtocolFamily;
33import java.net.StandardProtocolFamily;
34import java.net.StandardSocketOptions;
35import java.nio.ByteBuffer;
36import java.nio.channels.DatagramChannel;
37import java.nio.channels.UnsupportedAddressTypeException;
38import java.util.Enumeration;
39
40/**
41 * JdpBroadcaster is responsible for sending pre-built JDP packet across a Net
42 *
43 * <p> Multicast group address, port number and ttl have to be chosen on upper
44 * level and passed to broadcaster constructor. Also it's possible to specify
45 * source address to broadcast from. </p>
46 *
47 * <p>JdpBradcaster doesn't perform any validation on a supplied {@code port} and {@code ttl} because
48 * the allowed values depend on an operating system setup</p>
49 *
50 */
51public final class JdpBroadcaster {
52
53    private final InetAddress addr;
54    private final int port;
55    private final DatagramChannel channel;
56
57    /**
58     * Create a new broadcaster
59     *
60     * @param address - multicast group address
61     * @param srcAddress - address of interface we should use to broadcast.
62     * @param port - udp port to use
63     * @param ttl - packet ttl
64     * @throws IOException
65     */
66    public JdpBroadcaster(InetAddress address, InetAddress srcAddress, int port, int ttl)
67            throws IOException, JdpException {
68        this.addr = address;
69        this.port = port;
70
71        ProtocolFamily family = (address instanceof Inet6Address)
72                ? StandardProtocolFamily.INET6 : StandardProtocolFamily.INET;
73
74        channel = DatagramChannel.open(family);
75        channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
76        channel.setOption(StandardSocketOptions.IP_MULTICAST_TTL, ttl);
77
78        // with srcAddress equal to null, this constructor do exactly the same as
79        // if srcAddress is not passed
80        if (srcAddress != null) {
81            // User requests particular interface to bind to
82            NetworkInterface interf = NetworkInterface.getByInetAddress(srcAddress);
83
84            if (interf == null) {
85                throw new JdpException("Unable to get network interface for " + srcAddress.toString());
86            }
87
88            if (!interf.isUp()) {
89                throw new JdpException(interf.getName() + " is not up.");
90            }
91
92            if (!interf.supportsMulticast()) {
93                throw new JdpException(interf.getName() + " does not support multicast.");
94            }
95
96            try {
97                channel.bind(new InetSocketAddress(srcAddress, 0));
98            } catch (UnsupportedAddressTypeException ex) {
99                throw new JdpException("Unable to bind to source address");
100            }
101            channel.setOption(StandardSocketOptions.IP_MULTICAST_IF, interf);
102        }
103    }
104
105    /**
106     * Create a new broadcaster
107     *
108     * @param address - multicast group address
109     * @param port - udp port to use
110     * @param ttl - packet ttl
111     * @throws IOException
112     */
113    public JdpBroadcaster(InetAddress address, int port, int ttl)
114            throws IOException, JdpException {
115        this(address, null, port, ttl);
116    }
117
118    /**
119     * Broadcast pre-built packet
120     *
121     * @param packet - instance of JdpPacket
122     * @throws IOException
123     */
124    public void sendPacket(JdpPacket packet)
125            throws IOException {
126        byte[] data = packet.getPacketData();
127        // Unlike allocate/put wrap don't need a flip afterward
128        ByteBuffer b = ByteBuffer.wrap(data);
129        channel.send(b, new InetSocketAddress(addr, port));
130    }
131
132    /**
133     * Shutdown broadcaster and close underlying socket channel
134     *
135     * @throws IOException
136     */
137    public void shutdown() throws IOException {
138        channel.close();
139    }
140}
141