1 /*

     2  * Copyright 2002-2005 Sun Microsystems, Inc.  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.  Sun designates this

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

     9  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any 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.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 }