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 * Copyright (c) 2000, 2019, 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

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package java.net;

import java.io.IOException;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.ObjectStreamField;

import java.util.Enumeration;

import java.util.Arrays;

/**

 * 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>.

 *

 * <h2> <a id="format">Textual representation of IP addresses</a> </h2>

 *

 * Textual representation of IPv6 address used as input to methods

 * takes one of the following forms:

 *

 * <ol>

 *   <li><p> <a id="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><ul style="list-style-type:none">

 *   <li>{@code 1080:0:0:0:8:800:200C:417A}</li>

 *   </ul></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><ul style="list-style-type:none">

 *   <li>{@code 1080::8:800:200C:417A}</li>

 *   </ul></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><ul style="list-style-type:none">

 *   <li>{@code ::FFFF:129.144.52.38}</li>

 *   <li>{@code ::129.144.52.38}</li>

 *   </ul></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><ul style="list-style-type:none">

 *   <li>{@code ::FFFF:d.d.d}</li>

 *   <li>{@code ::FFFF:d.d}</li>

 *   <li>{@code ::d.d.d}</li>

 *   <li>{@code ::d.d}</li>

 *   </ul></blockquote>

 *

 *   <p> The following form:

 *

 *   <blockquote><ul style="list-style-type:none">

 *   <li>{@code ::FFFF:d}</li>

 *   </ul></blockquote>

 *

 *   <p> is valid, however it is an unconventional representation of

 *   the IPv4-compatible IPv6 address,

 *

 *   <blockquote><ul style="list-style-type:none">

 *   <li>{@code ::255.255.0.d}</li>

 *   </ul></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.

 *

 * <h3> Special IPv6 address </h3>

 *

 * <blockquote>

 * <table class="borderless">

 * <caption style="display:none">Description of IPv4-mapped address</caption>

 * <tr><th style="vertical-align:top; padding-right:2px"><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>

 *

 * <h3><a id="scoped">Textual representation of IPv6 scoped addresses</a></h3>

 *

 * <p> The textual representation of IPv6 addresses as described above can be

 * extended to specify IPv6 scoped addresses. This extension to the basic

 * addressing architecture is described in [draft-ietf-ipngwg-scoping-arch-04.txt].

 *

 * <p> Because link-local and site-local addresses are non-global, it is possible

 * that different hosts may have the same destination address and may be

 * reachable through different interfaces on the same originating system. In

 * this case, the originating system is said to be connected to multiple zones

 * of the same scope. In order to disambiguate which is the intended destination

 * zone, it is possible to append a zone identifier (or <i>scope_id</i>) to an

 * IPv6 address.

 *

 * <p> The general format for specifying the <i>scope_id</i> is the following:

 *

 * <blockquote><i>IPv6-address</i>%<i>scope_id</i></blockquote>

 * <p> The IPv6-address is a literal IPv6 address as described above.

 * The <i>scope_id</i> refers to an interface on the local system, and it can be

 * specified in two ways.

 * <ol><li><i>As a numeric identifier.</i> This must be a positive integer

 * that identifies the particular interface and scope as understood by the

 * system. Usually, the numeric values can be determined through administration

 * tools on the system. Each interface may have multiple values, one for each

 * scope. If the scope is unspecified, then the default value used is zero.</li>

 * <li><i>As a string.</i> This must be the exact string that is returned by

 * {@link java.net.NetworkInterface#getName()} for the particular interface in

 * question. When an Inet6Address is created in this way, the numeric scope-id

 * is determined at the time the object is created by querying the relevant

 * NetworkInterface.</li></ol>

 *

 * <p> Note also, that the numeric <i>scope_id</i> can be retrieved from

 * Inet6Address instances returned from the NetworkInterface class. This can be

 * used to find out the current scope ids configured on the system.

 * @since 1.4

 */

public final

class Inet6Address extends InetAddress {

    static final int INADDRSZ = 16;

    private class Inet6AddressHolder {

        private Inet6AddressHolder() {

            ipaddress = new byte[INADDRSZ];

        }

        private Inet6AddressHolder(

            byte[] ipaddress, int scope_id, boolean scope_id_set,

            NetworkInterface ifname, boolean scope_ifname_set)

        {

            this.ipaddress = ipaddress;

            this.scope_id = scope_id;

            this.scope_id_set = scope_id_set;

            this.scope_ifname_set = scope_ifname_set;

            this.scope_ifname = ifname;

        }

        /**

         * Holds a 128-bit (16 bytes) IPv6 address.

         */

        byte[] ipaddress;

        /**

         * scope_id. The scope specified when the object is created. If the object

         * is created with an interface name, then the scope_id is not determined

         * until the time it is needed.

         */

        int scope_id;  // 0

        /**

         * This will be set to true when the scope_id field contains a valid

         * integer scope_id.

         */

        boolean scope_id_set;  // false

        /**

         * scoped interface. scope_id is derived from this as the scope_id of the first

         * address whose scope is the same as this address for the named interface.

         */

        NetworkInterface scope_ifname;  // null

        /**

         * set if the object is constructed with a scoped

         * interface instead of a numeric scope id.

         */

        boolean scope_ifname_set; // false;

        void setAddr(byte addr[]) {

            if (addr.length == INADDRSZ) { // normal IPv6 address

                System.arraycopy(addr, 0, ipaddress, 0, INADDRSZ);

            }

        }

        void init(byte addr[], int scope_id) {

            setAddr(addr);

            if (scope_id >= 0) {

                this.scope_id = scope_id;

                this.scope_id_set = true;

            }

        }

        void init(byte addr[], NetworkInterface nif)

            throws UnknownHostException

        {

            setAddr(addr);

            if (nif != null) {

                this.scope_id = deriveNumericScope(ipaddress, nif);

                this.scope_id_set = true;

                this.scope_ifname = nif;

                this.scope_ifname_set = true;

            }

        }

        String getHostAddress() {

            String s = numericToTextFormat(ipaddress);

            if (scope_ifname != null) { /* must check this first */

                s = s + "%" + scope_ifname.getName();

            } else if (scope_id_set) {

                s = s + "%" + scope_id;

            }

            return s;

        }

        public boolean equals(Object o) {

            if (! (o instanceof Inet6AddressHolder)) {

                return false;

            }

            Inet6AddressHolder that = (Inet6AddressHolder)o;

            return Arrays.equals(this.ipaddress, that.ipaddress);

        }

        public int hashCode() {

            if (ipaddress != null) {

                int hash = 0;

                int i=0;

                while (i<INADDRSZ) {

                    int j=0;

                    int component=0;

                    while (j<4 && i<INADDRSZ) {

                        component = (component << 8) + ipaddress[i];

                        j++;

                        i++;

                    }

                    hash += component;

                }

                return hash;

            } else {

                return 0;

            }

        }

        boolean isIPv4CompatibleAddress() {

            if ((ipaddress[0] == 0x00) && (ipaddress[1] == 0x00) &&

                (ipaddress[2] == 0x00) && (ipaddress[3] == 0x00) &&

                (ipaddress[4] == 0x00) && (ipaddress[5] == 0x00) &&

                (ipaddress[6] == 0x00) && (ipaddress[7] == 0x00) &&

                (ipaddress[8] == 0x00) && (ipaddress[9] == 0x00) &&

                (ipaddress[10] == 0x00) && (ipaddress[11] == 0x00))  {

                return true;

            }

            return false;

        }

        boolean isMulticastAddress() {

            return ((ipaddress[0] & 0xff) == 0xff);

        }

        boolean isAnyLocalAddress() {

            byte test = 0x00;

            for (int i = 0; i < INADDRSZ; i++) {

                test |= ipaddress[i];

            }

            return (test == 0x00);

        }

        boolean isLoopbackAddress() {

            byte test = 0x00;

            for (int i = 0; i < 15; i++) {

                test |= ipaddress[i];

            }

            return (test == 0x00) && (ipaddress[15] == 0x01);

        }

        boolean isLinkLocalAddress() {

            return ((ipaddress[0] & 0xff) == 0xfe

                    && (ipaddress[1] & 0xc0) == 0x80);

        }

        boolean isSiteLocalAddress() {

            return ((ipaddress[0] & 0xff) == 0xfe

                    && (ipaddress[1] & 0xc0) == 0xc0);

        }

        boolean isMCGlobal() {

            return ((ipaddress[0] & 0xff) == 0xff

                    && (ipaddress[1] & 0x0f) == 0x0e);

        }

        boolean isMCNodeLocal() {

            return ((ipaddress[0] & 0xff) == 0xff

                    && (ipaddress[1] & 0x0f) == 0x01);

        }

        boolean isMCLinkLocal() {

            return ((ipaddress[0] & 0xff) == 0xff

                    && (ipaddress[1] & 0x0f) == 0x02);

        }

        boolean isMCSiteLocal() {

            return ((ipaddress[0] & 0xff) == 0xff

                    && (ipaddress[1] & 0x0f) == 0x05);

        }

        boolean isMCOrgLocal() {

            return ((ipaddress[0] & 0xff) == 0xff

                    && (ipaddress[1] & 0x0f) == 0x08);

        }

    }

    private final transient Inet6AddressHolder holder6;

    @java.io.Serial

    private static final long serialVersionUID = 6880410070516793377L;

    // Perform native initialization

    static { init(); }

    Inet6Address() {

        super();

        holder.init(null, IPv6);

        holder6 = new Inet6AddressHolder();

    }

    /* checking of value for scope_id should be done by caller

     * scope_id must be >= 0, or -1 to indicate not being set

     */

    Inet6Address(String hostName, byte addr[], int scope_id) {

        holder.init(hostName, IPv6);

        holder6 = new Inet6AddressHolder();

        holder6.init(addr, scope_id);

    }

    Inet6Address(String hostName, byte addr[]) {

        holder6 = new Inet6AddressHolder();

        try {

            initif (hostName, addr, null);

        } catch (UnknownHostException e) {} /* cant happen if ifname is null */

    }

    Inet6Address (String hostName, byte addr[], NetworkInterface nif)

        throws UnknownHostException

    {

        holder6 = new Inet6AddressHolder();

        initif (hostName, addr, nif);

    }

    Inet6Address (String hostName, byte addr[], String ifname)

        throws UnknownHostException

    {

        holder6 = new Inet6AddressHolder();

        initstr (hostName, addr, ifname);

    }

    /**

     * Create an Inet6Address in the exact manner of {@link

     * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is

     * set to the value corresponding to the given interface for the address

     * type specified in {@code addr}. The call will fail with an

     * UnknownHostException if the given interface does not have a numeric

     * scope_id assigned for the given address type (e.g. link-local or site-local).

     * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6

     * scoped addresses.

     *

     * @param host the specified host

     * @param addr the raw IP address in network byte order

     * @param nif an interface this address must be associated with.

     * @return  an Inet6Address object created from the raw IP address.

     * @throws  UnknownHostException

     *          if IP address is of illegal length, or if the interface does not

     *          have a numeric scope_id assigned for the given address type.

     *

     * @since 1.5

     */

    public static Inet6Address getByAddress(String host, byte[] addr,

                                            NetworkInterface nif)

        throws UnknownHostException

    {

        if (host != null && !host.isEmpty() && host.charAt(0) == '[') {

            if (host.charAt(host.length()-1) == ']') {

                host = host.substring(1, host.length() -1);

            }

        }

        if (addr != null) {

            if (addr.length == Inet6Address.INADDRSZ) {

                return new Inet6Address(host, addr, nif);

            }

        }

        throw new UnknownHostException("addr is of illegal length");

    }

    /**

     * Create an Inet6Address in the exact manner of {@link

     * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is

     * set to the given numeric value. The scope_id is not checked to determine

     * if it corresponds to any interface on the system.

     * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6

     * scoped addresses.

     *

     * @param host the specified host

     * @param addr the raw IP address in network byte order

     * @param scope_id the numeric scope_id for the address.

     * @return  an Inet6Address object created from the raw IP address.

     * @throws  UnknownHostException  if IP address is of illegal length.

     *

     * @since 1.5

     */

    public static Inet6Address getByAddress(String host, byte[] addr,

                                            int scope_id)

        throws UnknownHostException

    {

        if (host != null && !host.isEmpty() && host.charAt(0) == '[') {

            if (host.charAt(host.length()-1) == ']') {

                host = host.substring(1, host.length() -1);

            }

        }

        if (addr != null) {

            if (addr.length == Inet6Address.INADDRSZ) {

                return new Inet6Address(host, addr, scope_id);

            }

        }

        throw new UnknownHostException("addr is of illegal length");

    }

    private void initstr(String hostName, byte addr[], String ifname)

        throws UnknownHostException

    {

        try {

            NetworkInterface nif = NetworkInterface.getByName (ifname);

            if (nif == null) {

                throw new UnknownHostException ("no such interface " + ifname);

            }

            initif (hostName, addr, nif);

        } catch (SocketException e) {

            throw new UnknownHostException ("SocketException thrown" + ifname);

        }

    }

    private void initif(String hostName, byte addr[], NetworkInterface nif)

        throws UnknownHostException

    {

        int family = -1;

        holder6.init(addr, nif);

        if (addr.length == INADDRSZ) { // normal IPv6 address

            family = IPv6;

        }

        holder.init(hostName, family);