https://openjdk.java.net/ 
/*
 * Copyright (c) 2000, 2018, 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 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 
RFC 2373: IP Version 6 Addressing Architecture.

 Textual representation of IP addresses 

Textual representation of IPv6 address used as input to methods
takes one of the following forms:

    
  
  1.  The preferred form 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,
  
      
  
    • 1080:0:0:0:8:800:200C:417A
      • 
  
    
  
     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.
    2. 
  
  2.  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,
  
      
  
    • 1080::8:800:200C:417A
      • 
  
    
  
  3.  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,
  
      
  
    • ::FFFF:129.144.52.38
      • 
  
    • ::129.144.52.38
      • 
  
    
  
     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:
  
      
  
    • ::FFFF:d.d.d
      • 
  
    • ::FFFF:d.d
      • 
  
    • ::d.d.d
      • 
  
    • ::d.d
      • 
  
    
  
     The following form:
  
      
  
    • ::FFFF:d
      • 
  
    
  
     is valid, however it is an unconventional representation of
  the IPv4-compatible IPv6 address,
  
      
  
    • ::255.255.0.d
      • 
  
    
  
     while "::d" corresponds to the general IPv6 address
  "0:0:0:0:0:0:0:d".
    4. 



 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.

 Special IPv6 address 





Description of IPv4-mapped address

IPv4-mapped address
        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.
        
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.




Textual representation of IPv6 scoped addresses


 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].

 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 scope_id) to an
IPv6 address.

 The general format for specifying the scope_id is the following:

IPv6-address%scope_id


 The IPv6-address is a literal IPv6 address as described above.
The scope_id refers to an interface on the local system, and it can be
specified in two ways.

  1. As a numeric identifier. 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.
    2. 

  2. As a string. This must be the exact string that is returned by 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.


 Note also, that the numeric scope_id 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
/**
 * 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>.
 *
 * <h3> <a id="format">Textual representation of IP addresses</a> </h3>
 *
 * 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.
 *
 * <h4> Special IPv6 address </h4>
 *
 * <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>
 *
 * <h4><a id="scoped">Textual representation of IPv6 scoped addresses</a></h4>
 *
 * <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;

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

    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.

/**
         * 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.

/**
         * 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.

/**
         * 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.

/**
         * 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.

/**
         * 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;

    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 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 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 (eg. link-local or site-local). See here for a description of IPv6
scoped addresses.

Params:
  • host – the specified host
  • addr – the raw IP address in network byte order
  • nif – an interface this address must be associated with.
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.
Returns: an Inet6Address object created from the raw IP address.
Since:1.5
/**
     * 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 (eg. 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 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 here for a description of IPv6
scoped addresses.

Params:
  • host – the specified host
  • addr – the raw IP address in network byte order
  • scope_id – the numeric scope_id for the address.
Throws:
Returns: an Inet6Address object created from the raw IP address.
Since:1.5
/**
     * 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);
    }

    /* check the two Ipv6 addresses and return false if they are both
     * non global address types, but not the same.
     * (ie. one is sitelocal and the other linklocal)
     * return true otherwise.
     */

    private static boolean isDifferentLocalAddressType(
        byte[] thisAddr, byte[] otherAddr) {

        if (Inet6Address.isLinkLocalAddress(thisAddr) &&
                !Inet6Address.isLinkLocalAddress(otherAddr)) {
            return false;
        }
        if (Inet6Address.isSiteLocalAddress(thisAddr) &&
                !Inet6Address.isSiteLocalAddress(otherAddr)) {
            return false;
        }
        return true;
    }

    private static int deriveNumericScope (byte[] thisAddr, NetworkInterface ifc) throws UnknownHostException {
        Enumeration<InetAddress> addresses = ifc.getInetAddresses();
        while (addresses.hasMoreElements()) {
            InetAddress addr = addresses.nextElement();
            if (!(addr instanceof Inet6Address)) {
                continue;
            }
            Inet6Address ia6_addr = (Inet6Address)addr;
            /* check if site or link local prefixes match */
            if (!isDifferentLocalAddressType(thisAddr, ia6_addr.getAddress())){
                /* type not the same, so carry on searching */
                continue;
            }
            /* found a matching address - return its scope_id */
            return ia6_addr.getScopeId();
        }
        throw new UnknownHostException ("no scope_id found");
    }

    private int deriveNumericScope (String ifname) throws UnknownHostException {
        Enumeration<NetworkInterface> en;
        try {
            en = NetworkInterface.getNetworkInterfaces();
        } catch (SocketException e) {
            throw new UnknownHostException ("could not enumerate local network interfaces");
        }
        while (en.hasMoreElements()) {
            NetworkInterface ifc = en.nextElement();
            if (ifc.getName().equals (ifname)) {
                return deriveNumericScope(holder6.ipaddress, ifc);
            }
        }
        throw new UnknownHostException ("No matching address found for interface : " +ifname);
    }

    
@serialFieldipaddress byte[]
@serialFieldscope_id int
@serialFieldscope_id_set boolean
@serialFieldscope_ifname_set boolean
@serialFieldifname String
/**
     * @serialField ipaddress byte[]
     * @serialField scope_id int
     * @serialField scope_id_set boolean
     * @serialField scope_ifname_set boolean
     * @serialField ifname String
     */

    private static final ObjectStreamField[] serialPersistentFields = {
         new ObjectStreamField("ipaddress", byte[].class),
         new ObjectStreamField("scope_id", int.class),
         new ObjectStreamField("scope_id_set", boolean.class),
         new ObjectStreamField("scope_ifname_set", boolean.class),
         new ObjectStreamField("ifname", String.class)
    };

    private static final jdk.internal.misc.Unsafe UNSAFE
            = jdk.internal.misc.Unsafe.getUnsafe();
    private static final long FIELDS_OFFSET = UNSAFE.objectFieldOffset(
                Inet6Address.class, "holder6");

    
restore the state of this object from stream
including the scope information, only if the
scoped interface name is valid on this system

/**
     * restore the state of this object from stream
     * including the scope information, only if the
     * scoped interface name is valid on this system
     */
    private void readObject(ObjectInputStream s)
        throws IOException, ClassNotFoundException {
        NetworkInterface scope_ifname = null;

        if (getClass().getClassLoader() != null) {
            throw new SecurityException ("invalid address type");
        }

        ObjectInputStream.GetField gf = s.readFields();
        byte[] ipaddress = (byte[])gf.get("ipaddress", new byte[0]);
        int scope_id = gf.get("scope_id", -1);
        boolean scope_id_set = gf.get("scope_id_set", false);
        boolean scope_ifname_set = gf.get("scope_ifname_set", false);
        String ifname = (String)gf.get("ifname", null);

        if (ifname != null && !ifname.isEmpty()) {
            try {
                scope_ifname = NetworkInterface.getByName(ifname);
                if (scope_ifname == null) {
                    /* the interface does not exist on this system, so we clear
                     * the scope information completely */
                    scope_id_set = false;
                    scope_ifname_set = false;
                    scope_id = 0;
                } else {
                    scope_ifname_set = true;
                    try {
                        scope_id = deriveNumericScope (ipaddress, scope_ifname);
                    } catch (UnknownHostException e) {
                        // typically should not happen, but it may be that
                        // the machine being used for deserialization has
                        // the same interface name but without IPv6 configured.
                    }
                }
            } catch (SocketException e) {}
        }

        /* if ifname was not supplied, then the numeric info is used */

        ipaddress = ipaddress.clone();

        // Check that our invariants are satisfied
        if (ipaddress.length != INADDRSZ) {
            throw new InvalidObjectException("invalid address length: "+
                                             ipaddress.length);
        }

        if (holder.getFamily() != IPv6) {
            throw new InvalidObjectException("invalid address family type");
        }

        Inet6AddressHolder h = new Inet6AddressHolder(
            ipaddress, scope_id, scope_id_set, scope_ifname, scope_ifname_set
        );

        UNSAFE.putObject(this, FIELDS_OFFSET, h);
    }

    
default behavior is overridden in order to write the
scope_ifname field as a String, rather than a NetworkInterface
which is not serializable

/**
     * default behavior is overridden in order to write the
     * scope_ifname field as a String, rather than a NetworkInterface
     * which is not serializable
     */
    private synchronized void writeObject(ObjectOutputStream s)
        throws IOException
    {
            String ifname = null;

        if (holder6.scope_ifname != null) {
            ifname = holder6.scope_ifname.getName();
            holder6.scope_ifname_set = true;
        }
        ObjectOutputStream.PutField pfields = s.putFields();
        pfields.put("ipaddress", holder6.ipaddress);
        pfields.put("scope_id", holder6.scope_id);
        pfields.put("scope_id_set", holder6.scope_id_set);
        pfields.put("scope_ifname_set", holder6.scope_ifname_set);
        pfields.put("ifname", ifname);
        s.writeFields();
    }

    
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.

Returns:a boolean indicating if the InetAddress is an IP multicast address
/**
     * 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} indicating if the InetAddress is an IP
     *         multicast address
     */
    @Override
    public boolean isMulticastAddress() {
        return holder6.isMulticastAddress();
    }

    
Utility routine to check if the InetAddress is a wildcard address.

Returns:a boolean indicating if the Inetaddress is a wildcard address.
/**
     * Utility routine to check if the InetAddress is a wildcard address.
     *
     * @return a {@code boolean} indicating if the Inetaddress is
     *         a wildcard address.
     */
    @Override
    public boolean isAnyLocalAddress() {
        return holder6.isAnyLocalAddress();
    }

    
Utility routine to check if the InetAddress is a loopback address.

Returns:a boolean indicating if the InetAddress is a loopback address; or false otherwise.
/**
     * Utility routine to check if the InetAddress is a loopback address.
     *
     * @return a {@code boolean} indicating if the InetAddress is a loopback
     *         address; or false otherwise.
     */
    @Override
    public boolean isLoopbackAddress() {
        return holder6.isLoopbackAddress();
    }

    
Utility routine to check if the InetAddress is an link local address.

Returns:a boolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.
/**
     * Utility routine to check if the InetAddress is an link local address.
     *
     * @return a {@code boolean} indicating if the InetAddress is a link local
     *         address; or false if address is not a link local unicast address.
     */
    @Override
    public boolean isLinkLocalAddress() {
        return holder6.isLinkLocalAddress();
    }

    /* static version of above */
    static boolean isLinkLocalAddress(byte[] ipaddress) {
        return ((ipaddress[0] & 0xff) == 0xfe
                && (ipaddress[1] & 0xc0) == 0x80);
    }

    
Utility routine to check if the InetAddress is a site local address.

Returns:a boolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.
/**
     * Utility routine to check if the InetAddress is a site local address.
     *
     * @return a {@code boolean} indicating if the InetAddress is a site local
     *         address; or false if address is not a site local unicast address.
     */
    @Override
    public boolean isSiteLocalAddress() {
        return holder6.isSiteLocalAddress();
    }

    /* static version of above */
    static boolean isSiteLocalAddress(byte[] ipaddress) {
        return ((ipaddress[0] & 0xff) == 0xfe
                && (ipaddress[1] & 0xc0) == 0xc0);
    }

    
Utility routine to check if the multicast address has global scope.

Returns:a boolean 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
/**
     * Utility routine to check if the multicast address has global scope.
     *
     * @return a {@code boolean} 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
     */
    @Override
    public boolean isMCGlobal() {
        return holder6.isMCGlobal();
    }

    
Utility routine to check if the multicast address has node scope.

Returns:a boolean 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
/**
     * Utility routine to check if the multicast address has node scope.
     *
     * @return a {@code boolean} 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
     */
    @Override
    public boolean isMCNodeLocal() {
        return holder6.isMCNodeLocal();
    }

    
Utility routine to check if the multicast address has link scope.

Returns:a boolean 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
/**
     * Utility routine to check if the multicast address has link scope.
     *
     * @return a {@code boolean} 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
     */
    @Override
    public boolean isMCLinkLocal() {
        return holder6.isMCLinkLocal();
    }

    
Utility routine to check if the multicast address has site scope.

Returns:a boolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has site scope.
     *
     * @return a {@code boolean} indicating if the address has is a multicast
     *         address of site-local scope, false if it is not  of site-local
     *         scope or it is not a multicast address
     */
    @Override
    public boolean isMCSiteLocal() {
        return holder6.isMCSiteLocal();
    }

    
Utility routine to check if the multicast address has organization scope.

Returns:a boolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address
/**
     * Utility routine to check if the multicast address has organization scope.
     *
     * @return a {@code boolean} indicating if the address has is a multicast
     *         address of organization-local scope, false if it is not of
     *         organization-local scope or it is not a multicast address
     */
    @Override
    public boolean isMCOrgLocal() {
        return holder6.isMCOrgLocal();
    }
    
Returns the raw IP address of this InetAddress object. The result is in network byte order: the highest order byte of the address is in getAddress()[0]. 
Returns: the raw IP address of this object.
/**
     * Returns the raw IP address of this {@code InetAddress} object. The result
     * is in network byte order: the highest order byte of the address is in
     * {@code getAddress()[0]}.
     *
     * @return  the raw IP address of this object.
     */
    @Override
    public byte[] getAddress() {
        return holder6.ipaddress.clone();
    }

    
Returns the numeric scopeId, if this instance is associated with
an interface. If no scoped_id is set, the returned value is zero.

Returns:the scopeId, or zero if not set.
Since:1.5
/**
     * Returns the numeric scopeId, if this instance is associated with
     * an interface. If no scoped_id is set, the returned value is zero.
     *
     * @return the scopeId, or zero if not set.
     *
     * @since 1.5
     */
     public int getScopeId() {
        return holder6.scope_id;
     }

    
Returns the scoped interface, if this instance was created with
with a scoped interface.

Returns:the scoped interface, or null if not set.
Since:1.5
/**
     * Returns the scoped interface, if this instance was created with
     * with a scoped interface.
     *
     * @return the scoped interface, or null if not set.
     * @since 1.5
     */
     public NetworkInterface getScopedInterface() {
        return holder6.scope_ifname;
     }

    
Returns the IP address string in textual presentation. If the instance
was created specifying a scope identifier then the scope id is appended
to the IP address preceded by a "%" (per-cent) character. This can be
either a numeric value or a string, depending on which was used to create
the instance.

Returns: the raw IP address in a string format.
/**
     * Returns the IP address string in textual presentation. If the instance
     * was created specifying a scope identifier then the scope id is appended
     * to the IP address preceded by a "%" (per-cent) character. This can be
     * either a numeric value or a string, depending on which was used to create
     * the instance.
     *
     * @return  the raw IP address in a string format.
     */
    @Override
    public String getHostAddress() {
        return holder6.getHostAddress();
    }

    
Returns a hashcode for this IP address.

Returns: a hash code value for this IP address.
/**
     * Returns a hashcode for this IP address.
     *
     * @return  a hash code value for this IP address.
     */
    @Override
    public int hashCode() {
        return holder6.hashCode();
    }

    
Compares this object against the specified object. The result is 
true if and only if the argument is not null and it represents the same IP address as this object. 
 Two instances of InetAddress represent the same IP address if the length of the byte arrays returned by getAddress is the same for both, and each of the array components is the same for the byte arrays. 
Params:
  • obj –   the object to compare against.
See Also:
Returns: true if the objects are the same; false otherwise.
/**
     * Compares this object against the specified object. The result is {@code
     * true} if and only if the argument is not {@code null} and it represents
     * the same IP address as this object.
     *
     * <p> Two instances of {@code InetAddress} represent the same IP address
     * if the length of the byte arrays returned by {@code getAddress} is the
     * same for both, and each of the array components is the same for the byte
     * arrays.
     *
     * @param   obj   the object to compare against.
     *
     * @return  {@code true} if the objects are the same; {@code false} otherwise.
     *
     * @see     java.net.InetAddress#getAddress()
     */
    @Override
    public boolean equals(Object obj) {
        if (obj == null || !(obj instanceof Inet6Address))
            return false;

        Inet6Address inetAddr = (Inet6Address)obj;

        return holder6.equals(inetAddr.holder6);
    }

    
Utility routine to check if the InetAddress is an
IPv4 compatible IPv6 address.

Returns:a boolean indicating if the InetAddress is an IPv4 compatible IPv6 address; or false if address is IPv4 address.
/**
     * Utility routine to check if the InetAddress is an
     * IPv4 compatible IPv6 address.
     *
     * @return a {@code boolean} indicating if the InetAddress is an IPv4
     *         compatible IPv6 address; or false if address is IPv4 address.
     */
    public boolean isIPv4CompatibleAddress() {
        return holder6.isIPv4CompatibleAddress();
    }

    // Utilities

    private static final int INT16SZ = 2;

    
Convert IPv6 binary address into presentation (printable) format.

Params:
  • src – a byte array representing the IPv6 numeric address
Returns:a String representing an IPv6 address in
        textual representation format
/**
     * Convert IPv6 binary address into presentation (printable) format.
     *
     * @param src a byte array representing the IPv6 numeric address
     * @return a String representing an IPv6 address in
     *         textual representation format
     */
    static String numericToTextFormat(byte[] src) {
        StringBuilder sb = new StringBuilder(39);
        for (int i = 0; i < (INADDRSZ / INT16SZ); i++) {
            sb.append(Integer.toHexString(((src[i<<1]<<8) & 0xff00)
                                          | (src[(i<<1)+1] & 0xff)));
            if (i < (INADDRSZ / INT16SZ) -1 ) {
               sb.append(":");
            }
        }
        return sb.toString();
    }

    
Perform class load-time initializations.

/**
     * Perform class load-time initializations.
     */
    private static native void init();
}