convert From IPv4 Mapped IPv6 Address - Java Network

Java examples for Network:IP Address

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Description

convert From IPv4 Mapped IPv6 Address

Demo Code

/*//from  w  w w  . jav a  2 s. c  o  m
 * Copyright (c) 2004, 2015, 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 com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] addr = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        System.out.println(java.util.Arrays
                .toString(convertFromIPv4MappedAddress(addr)));
    }

    private static final int INADDR4SZ = 4;
    private static final int INADDR16SZ = 16;

    public static byte[] convertFromIPv4MappedAddress(byte[] addr) {
        if (isIPv4MappedAddress(addr)) {
            byte[] newAddr = new byte[INADDR4SZ];
            System.arraycopy(addr, 12, newAddr, 0, INADDR4SZ);
            return newAddr;
        }
        return null;
    }

    /**
     * Utility routine to check if the InetAddress is an
     * IPv4 mapped IPv6 address.
     *
     * @return a <code>boolean</code> indicating if the InetAddress is
     * an IPv4 mapped IPv6 address; or false if address is IPv4 address.
     */
    private static boolean isIPv4MappedAddress(byte[] addr) {
        if (addr.length < INADDR16SZ) {
            return false;
        }
        if ((addr[0] == 0x00) && (addr[1] == 0x00) && (addr[2] == 0x00)
                && (addr[3] == 0x00) && (addr[4] == 0x00)
                && (addr[5] == 0x00) && (addr[6] == 0x00)
                && (addr[7] == 0x00) && (addr[8] == 0x00)
                && (addr[9] == 0x00) && (addr[10] == (byte) 0xff)
                && (addr[11] == (byte) 0xff)) {
            return true;
        }
        return false;
    }
}

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