inet6address.java

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/*
 * @(#)Inet6Address.java	1.28 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program 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. 
 * 
 * This program 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 at /legal/license.txt). 
 * 
 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 */

package java.net;

import java.security.AccessController;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.io.ObjectStreamException;
import java.io.InvalidObjectException;
import sun.security.action.*;

/**
 * This class represents an Internet Protocol version 6 (IPv6) address.
 * Defined by <a href="http://www.ietf.org/rfc/rfc2373.txt">
 * <i>RFC&nbsp;2373: IP Version 6 Addressing Architecture</i></a>.
 *
 * <h4> <A NAME="format">Textual representation of IP addresses<a> </h4>
 *
 * Textual representation of IPv6 address used as input to methods
 * takes one of the following forms:
 * 
 * <ol>
 *   <li><p> <A NAME="lform">The preferred form<a> is x:x:x:x:x:x:x:x, where the 'x's are
 *   the hexadecimal values of the eight 16-bit pieces of the
 *   address. This is the full form.  For example,
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>1080:0:0:0:8:800:200C:417A</tt><td></tr>
 *   </table></blockquote>
 *
 *   <p> Note that it is not necessary to write the leading zeros in
 *   an individual field. However, there must be at least one numeral
 *   in every field, except as described below.</li>
 *
 *   <li><p> Due to some methods of allocating certain styles of IPv6
 *   addresses, it will be common for addresses to contain long
 *   strings of zero bits. In order to make writing addresses
 *   containing zero bits easier, a special syntax is available to
 *   compress the zeros. The use of "::" indicates multiple groups
 *   of 16-bits of zeros. The "::" can only appear once in an address.
 *   The "::" can also be used to compress the leading and/or trailing
 *   zeros in an address. For example,
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>1080::8:800:200C:417A</tt><td></tr>
 *   </table></blockquote>
 *
 *   <li><p> An alternative form that is sometimes more convenient
 *   when dealing with a mixed environment of IPv4 and IPv6 nodes is
 *   x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values
 *   of the six high-order 16-bit pieces of the address, and the 'd's
 *   are the decimal values of the four low-order 8-bit pieces of the
 *   standard IPv4 representation address, for example,
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>::FFFF:129.144.52.38</tt><td></tr>
 *   <tr><td><tt>::129.144.52.38</tt><td></tr>
 *   </table></blockquote>
 *
 *   <p> where "::FFFF:d.d.d.d" and "::d.d.d.d" are, respectively, the
 *   general forms of an IPv4-mapped IPv6 address and an
 *   IPv4-compatible IPv6 address. Note that the IPv4 portion must be
 *   in the "d.d.d.d" form. The following forms are invalid:
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>::FFFF:d.d.d</tt><td></tr>
 *   <tr><td><tt>::FFFF:d.d</tt><td></tr>
 *   <tr><td><tt>::d.d.d</tt><td></tr>
 *   <tr><td><tt>::d.d</tt><td></tr>
 *   </table></blockquote>
 *
 *   <p> The following form:
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>::FFFF:d</tt><td></tr>
 *   </table></blockquote>
 *
 *   <p> is valid, however it is an unconventional representation of
 *   the IPv4-compatible IPv6 address,
 *
 *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 *   <tr><td><tt>::255.255.0.d</tt><td></tr>
 *   </table></blockquote>
 *
 *   <p> while "::d" corresponds to the general IPv6 address
 *   "0:0:0:0:0:0:0:d".</li>
 * </ol>
 *
 * <p> For methods that return a textual representation as output
 * value, the full form is used. Inet6Address will return the full
 * form because it is unambiguous when used in combination with other
 * textual data.
 *
 * <h4> Special IPv6 address </h4>
 *
 * <blockquote>
 * <table cellspacing=2 summary="Description of IPv4-mapped address"> <tr><th valign=top><i>IPv4-mapped address</i></th>
 *         <td>Of the form::ffff:w.x.y.z, this IPv6 address is used to
 *         represent an IPv4 address. It allows the native program to
 *         use the same address data structure and also the same
 *         socket when communicating with both IPv4 and IPv6 nodes.
 *
 *         <p>In InetAddress and Inet6Address, it is used for internal
 *         representation; it has no functional role. Java will never
 *         return an IPv4-mapped address.  These classes can take an
 *         IPv4-mapped address as input, both in byte array and text
 *         representation. However, it will be converted into an IPv4
 *         address.</td></tr>
 * </table></blockquote>
 */
public final
class Inet6Address extends InetAddress {
    final static int INADDRSZ = 16;

    /* 
     * cached scope_id - for link-local address use only.
     */
    private transient int cached_scope_id = 0;

    /**
     * Holds a 128-bit (16 bytes) IPv6 address.
     *
     * @serial
     */
    byte[] ipaddress;

    private static final long serialVersionUID = 6880410070516793377L;

    /*
     * Perform initializations.
     */
    static {
        init();
    }

    Inet6Address() {
	super();
	hostName = null;
	ipaddress = new byte[INADDRSZ];
	family = IPv6;
    }

    Inet6Address(String hostName, byte addr[]) {
	this.hostName = hostName;
	if (addr.length == INADDRSZ) { // normal IPv6 address
	    family = IPv6;
	    ipaddress = (byte[])addr.clone();
	} 
    }

    private void readObject(ObjectInputStream s) 
	throws IOException, ClassNotFoundException {
	s.defaultReadObject();
	
	ipaddress = (byte[])ipaddress.clone();

	// Check that our invariants are satisfied
	if (ipaddress.length != INADDRSZ) {
	    throw new InvalidObjectException("invalid address length: "+
					     ipaddress.length);
	}
	
	if (family != IPv6) {
	    throw new InvalidObjectException("invalid address family type");
	}
    }
    
    /**
     * Utility routine to check if the InetAddress is an IP multicast
     * address. 11111111 at the start of the address identifies the
     * address as being a multicast address.
     *
     * @return a <code>boolean</code> indicating if the InetAddress is
     * an IP multicast address
     * @since JDK1.1
     */
    public boolean isMulticastAddress() {
	return ((ipaddress[0] & 0xff) == 0xff);
    }

    /**
     * Utility routine to check if the InetAddress in a wildcard address.
     * @return a <code>boolean</code> indicating if the Inetaddress is
     *         a wildcard address.
     * @since 1.4
     */        
    public boolean isAnyLocalAddress() {
	byte test = 0x00;
	for (int i = 0; i < INADDRSZ; i++) {
	    test |= ipaddress[i];
	}
	return (test == 0x00);
    }

    /**
     * Utility routine to check if the InetAddress is a loopback address. 
     *
     * @return a <code>boolean</code> indicating if the InetAddress is 
     * a loopback address; or false otherwise.
     * @since 1.4
     */
    public boolean isLoopbackAddress() {
	byte test = 0x00;
	for (int i = 0; i < 15; i++) {
	    test |= ipaddress[i];
	}
	return (test == 0x00) && (ipaddress[15] == 0x01);
    }

    /**
     * Utility routine to check if the InetAddress is an link local address. 
     *
     * @return a <code>boolean</code> indicating if the InetAddress is 
     * a link local address; or false if address is not a link local unicast address.
     * @since 1.4
     */
    public boolean isLinkLocalAddress() {
	return ((ipaddress[0] & 0xff) == 0xfe 
		&& (ipaddress[1] & 0xc0) == 0x80);
    }

    /**
     * Utility routine to check if the InetAddress is a site local address. 
     *
     * @return a <code>boolean</code> indicating if the InetAddress is 
     * a site local address; or false if address is not a site local unicast address.
     * @since 1.4
     */
    public boolean isSiteLocalAddress() {
	return ((ipaddress[0] & 0xff) == 0xfe 
		&& (ipaddress[1] & 0xc0) == 0xc0);
    }

    /**
     * Utility routine to check if the multicast address has global scope.
     *
     * @return a <code>boolean</code> indicating if the address has 
     *         is a multicast address of global scope, false if it is not 
     *         of global scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCGlobal() {
	return ((ipaddress[0] & 0xff) == 0xff
		&& (ipaddress[1] & 0x0f) == 0x0e);
    }

    /**
     * Utility routine to check if the multicast address has node scope.
     *
     * @return a <code>boolean</code> indicating if the address has 
     *         is a multicast address of node-local scope, false if it is not 
     *         of node-local scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCNodeLocal() {
	return ((ipaddress[0] & 0xff) == 0xff
		&& (ipaddress[1] & 0x0f) == 0x01);
    }

    /**
     * Utility routine to check if the multicast address has link scope.
     *
     * @return a <code>boolean</code> indicating if the address has 
     *         is a multicast address of link-local scope, false if it is not 
     *         of link-local scope or it is not a multicast address
     * @since 1.4
     */
    public boolean isMCLinkLocal() {
	return ((ipaddress[0] & 0xff) == 0xff