1 /*
   2  * Copyright (c) 2002, 2005, 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  */
  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 {
  34     public native String getLocalHostName() throws UnknownHostException;
  35     public native InetAddress[]
  36         lookupAllHostAddr(String hostname) throws UnknownHostException;
  37     public native String getHostByAddr(byte[] addr) throws UnknownHostException;
  38     private native boolean isReachable0(byte[] addr, int timeout, byte[] ifaddr, int ttl) throws IOException;
  39 
  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 
  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 
  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 it = netif.getInetAddresses();
  63           InetAddress inetaddr = null;
  64           while (!(inetaddr instanceof Inet4Address) &&
  65                  it.hasMoreElements())
  66               inetaddr = (InetAddress) 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 }