1 /*
2  * Copyright (c) 2002, 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
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24  */
25 package java.net;
26 import java.io.IOException;
27 
28 /*
29  * Package private implementation of InetAddressImpl for IPv4.
30  *
31  * @since 1.4
32  */
33 class Inet4AddressImpl implements InetAddressImpl {
getLocalHostName()34     public native String getLocalHostName() throws UnknownHostException;
35     public native InetAddress[]
lookupAllHostAddr(String hostname)36         lookupAllHostAddr(String hostname) throws UnknownHostException;
getHostByAddr(byte[] addr)37     public native String getHostByAddr(byte[] addr) throws UnknownHostException;
isReachable0(byte[] addr, int timeout, byte[] ifaddr, int ttl)38     private native boolean isReachable0(byte[] addr, int timeout, byte[] ifaddr, int ttl) throws IOException;
39 
anyLocalAddress()40     public synchronized InetAddress anyLocalAddress() {
41         if (anyLocalAddress == null) {
42             anyLocalAddress = new Inet4Address(); // {0x00,0x00,0x00,0x00}
43             anyLocalAddress.holder().hostName = "0.0.0.0";
44         }
45         return anyLocalAddress;
46     }
47 
loopbackAddress()48     public synchronized InetAddress loopbackAddress() {
49         if (loopbackAddress == null) {
50             byte[] loopback = {0x7f,0x00,0x00,0x01};
51             loopbackAddress = new Inet4Address("localhost", loopback);
52         }
53         return loopbackAddress;
54     }
55 
isReachable(InetAddress addr, int timeout, NetworkInterface netif, int ttl)56   public boolean isReachable(InetAddress addr, int timeout, NetworkInterface netif, int ttl) throws IOException {
57       byte[] ifaddr = null;
58       if (netif != null) {
59           /*
60            * Let's make sure we use an address of the proper family
61            */
62           java.util.Enumeration<InetAddress> it = netif.getInetAddresses();
63           InetAddress inetaddr = null;
64           while (!(inetaddr instanceof Inet4Address) &&
65                  it.hasMoreElements())
66               inetaddr = it.nextElement();
67           if (inetaddr instanceof Inet4Address)
68               ifaddr = inetaddr.getAddress();
69       }
70       return isReachable0(addr.getAddress(), timeout, ifaddr, ttl);
71   }
72     private InetAddress      anyLocalAddress;
73     private InetAddress      loopbackAddress;
74 }
75