1 /*
   2  * Copyright (c) 2000, 2019, Oracle and/or its affiliates. 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.net;
  27 
  28 import java.io.IOException;
  29 import java.io.InvalidObjectException;
  30 import java.io.ObjectInputStream;
  31 import java.io.ObjectOutputStream;
  32 import java.io.ObjectStreamField;
  33 import java.util.Enumeration;
  34 import java.util.Arrays;
  35 
  36 /**
  37  * This class represents an Internet Protocol version 6 (IPv6) address.
  38  * Defined by <a href="http://www.ietf.org/rfc/rfc2373.txt">
  39  * <i>RFC&nbsp;2373: IP Version 6 Addressing Architecture</i></a>.
  40  *
  41  * <h2> <a id="format">Textual representation of IP addresses</a> </h2>
  42  *
  43  * Textual representation of IPv6 address used as input to methods
  44  * takes one of the following forms:
  45  *
  46  * <ol>
  47  *   <li><p> <a id="lform">The preferred form</a> is x:x:x:x:x:x:x:x,
  48  *   where the 'x's are
  49  *   the hexadecimal values of the eight 16-bit pieces of the
  50  *   address. This is the full form.  For example,
  51  *
  52  *   <blockquote><ul style="list-style-type:none">
  53  *   <li>{@code 1080:0:0:0:8:800:200C:417A}</li>
  54  *   </ul></blockquote>
  55  *
  56  *   <p> Note that it is not necessary to write the leading zeros in
  57  *   an individual field. However, there must be at least one numeral
  58  *   in every field, except as described below.</li>
  59  *
  60  *   <li><p> Due to some methods of allocating certain styles of IPv6
  61  *   addresses, it will be common for addresses to contain long
  62  *   strings of zero bits. In order to make writing addresses
  63  *   containing zero bits easier, a special syntax is available to
  64  *   compress the zeros. The use of "::" indicates multiple groups
  65  *   of 16-bits of zeros. The "::" can only appear once in an address.
  66  *   The "::" can also be used to compress the leading and/or trailing
  67  *   zeros in an address. For example,
  68  *
  69  *   <blockquote><ul style="list-style-type:none">
  70  *   <li>{@code 1080::8:800:200C:417A}</li>
  71  *   </ul></blockquote>
  72  *
  73  *   <li><p> An alternative form that is sometimes more convenient
  74  *   when dealing with a mixed environment of IPv4 and IPv6 nodes is
  75  *   x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values
  76  *   of the six high-order 16-bit pieces of the address, and the 'd's
  77  *   are the decimal values of the four low-order 8-bit pieces of the
  78  *   standard IPv4 representation address, for example,
  79  *
  80  *   <blockquote><ul style="list-style-type:none">
  81  *   <li>{@code ::FFFF:129.144.52.38}</li>
  82  *   <li>{@code ::129.144.52.38}</li>
  83  *   </ul></blockquote>
  84  *
  85  *   <p> where "::FFFF:d.d.d.d" and "::d.d.d.d" are, respectively, the
  86  *   general forms of an IPv4-mapped IPv6 address and an
  87  *   IPv4-compatible IPv6 address. Note that the IPv4 portion must be
  88  *   in the "d.d.d.d" form. The following forms are invalid:
  89  *
  90  *   <blockquote><ul style="list-style-type:none">
  91  *   <li>{@code ::FFFF:d.d.d}</li>
  92  *   <li>{@code ::FFFF:d.d}</li>
  93  *   <li>{@code ::d.d.d}</li>
  94  *   <li>{@code ::d.d}</li>
  95  *   </ul></blockquote>
  96  *
  97  *   <p> The following form:
  98  *
  99  *   <blockquote><ul style="list-style-type:none">
 100  *   <li>{@code ::FFFF:d}</li>
 101  *   </ul></blockquote>
 102  *
 103  *   <p> is valid, however it is an unconventional representation of
 104  *   the IPv4-compatible IPv6 address,
 105  *
 106  *   <blockquote><ul style="list-style-type:none">
 107  *   <li>{@code ::255.255.0.d}</li>
 108  *   </ul></blockquote>
 109  *
 110  *   <p> while "::d" corresponds to the general IPv6 address
 111  *   "0:0:0:0:0:0:0:d".</li>
 112  * </ol>
 113  *
 114  * <p> For methods that return a textual representation as output
 115  * value, the full form is used. Inet6Address will return the full
 116  * form because it is unambiguous when used in combination with other
 117  * textual data.
 118  *
 119  * <h3> Special IPv6 address </h3>
 120  *
 121  * <blockquote>
 122  * <table class="borderless">
 123  * <caption style="display:none">Description of IPv4-mapped address</caption>
 124  * <tr><th style="vertical-align:top; padding-right:2px"><i>IPv4-mapped address</i></th>
 125  *         <td>Of the form ::ffff:w.x.y.z, this IPv6 address is used to
 126  *         represent an IPv4 address. It allows the native program to
 127  *         use the same address data structure and also the same
 128  *         socket when communicating with both IPv4 and IPv6 nodes.
 129  *
 130  *         <p>In InetAddress and Inet6Address, it is used for internal
 131  *         representation; it has no functional role. Java will never
 132  *         return an IPv4-mapped address.  These classes can take an
 133  *         IPv4-mapped address as input, both in byte array and text
 134  *         representation. However, it will be converted into an IPv4
 135  *         address.</td></tr>
 136  * </table></blockquote>
 137  *
 138  * <h3><a id="scoped">Textual representation of IPv6 scoped addresses</a></h3>
 139  *
 140  * <p> The textual representation of IPv6 addresses as described above can be
 141  * extended to specify IPv6 scoped addresses. This extension to the basic
 142  * addressing architecture is described in [draft-ietf-ipngwg-scoping-arch-04.txt].
 143  *
 144  * <p> Because link-local and site-local addresses are non-global, it is possible
 145  * that different hosts may have the same destination address and may be
 146  * reachable through different interfaces on the same originating system. In
 147  * this case, the originating system is said to be connected to multiple zones
 148  * of the same scope. In order to disambiguate which is the intended destination
 149  * zone, it is possible to append a zone identifier (or <i>scope_id</i>) to an
 150  * IPv6 address.
 151  *
 152  * <p> The general format for specifying the <i>scope_id</i> is the following:
 153  *
 154  * <blockquote><i>IPv6-address</i>%<i>scope_id</i></blockquote>
 155  * <p> The IPv6-address is a literal IPv6 address as described above.
 156  * The <i>scope_id</i> refers to an interface on the local system, and it can be
 157  * specified in two ways.
 158  * <ol><li><i>As a numeric identifier.</i> This must be a positive integer
 159  * that identifies the particular interface and scope as understood by the
 160  * system. Usually, the numeric values can be determined through administration
 161  * tools on the system. Each interface may have multiple values, one for each
 162  * scope. If the scope is unspecified, then the default value used is zero.</li>
 163  * <li><i>As a string.</i> This must be the exact string that is returned by
 164  * {@link java.net.NetworkInterface#getName()} for the particular interface in
 165  * question. When an Inet6Address is created in this way, the numeric scope-id
 166  * is determined at the time the object is created by querying the relevant
 167  * NetworkInterface.</li></ol>
 168  *
 169  * <p> Note also, that the numeric <i>scope_id</i> can be retrieved from
 170  * Inet6Address instances returned from the NetworkInterface class. This can be
 171  * used to find out the current scope ids configured on the system.
 172  * @since 1.4
 173  */
 174 
 175 public final
 176 class Inet6Address extends InetAddress {
 177     static final int INADDRSZ = 16;
 178 
 179     private class Inet6AddressHolder {
 180 
 181         private Inet6AddressHolder() {
 182             ipaddress = new byte[INADDRSZ];
 183         }
 184 
 185         private Inet6AddressHolder(
 186             byte[] ipaddress, int scope_id, boolean scope_id_set,
 187             NetworkInterface ifname, boolean scope_ifname_set)
 188         {
 189             this.ipaddress = ipaddress;
 190             this.scope_id = scope_id;
 191             this.scope_id_set = scope_id_set;
 192             this.scope_ifname_set = scope_ifname_set;
 193             this.scope_ifname = ifname;
 194         }
 195 
 196         /**
 197          * Holds a 128-bit (16 bytes) IPv6 address.
 198          */
 199         byte[] ipaddress;
 200 
 201         /**
 202          * scope_id. The scope specified when the object is created. If the object
 203          * is created with an interface name, then the scope_id is not determined
 204          * until the time it is needed.
 205          */
 206         int scope_id;  // 0
 207 
 208         /**
 209          * This will be set to true when the scope_id field contains a valid
 210          * integer scope_id.
 211          */
 212         boolean scope_id_set;  // false
 213 
 214         /**
 215          * scoped interface. scope_id is derived from this as the scope_id of the first
 216          * address whose scope is the same as this address for the named interface.
 217          */
 218         NetworkInterface scope_ifname;  // null
 219 
 220         /**
 221          * set if the object is constructed with a scoped
 222          * interface instead of a numeric scope id.
 223          */
 224         boolean scope_ifname_set; // false;
 225 
 226         void setAddr(byte addr[]) {
 227             if (addr.length == INADDRSZ) { // normal IPv6 address
 228                 System.arraycopy(addr, 0, ipaddress, 0, INADDRSZ);
 229             }
 230         }
 231 
 232         void init(byte addr[], int scope_id) {
 233             setAddr(addr);
 234 
 235             if (scope_id >= 0) {
 236                 this.scope_id = scope_id;
 237                 this.scope_id_set = true;
 238             }
 239         }
 240 
 241         void init(byte addr[], NetworkInterface nif)
 242             throws UnknownHostException
 243         {
 244             setAddr(addr);
 245 
 246             if (nif != null) {
 247                 this.scope_id = deriveNumericScope(ipaddress, nif);
 248                 this.scope_id_set = true;
 249                 this.scope_ifname = nif;
 250                 this.scope_ifname_set = true;
 251             }
 252         }
 253 
 254         String getHostAddress() {
 255             String s = numericToTextFormat(ipaddress);
 256             if (scope_ifname != null) { /* must check this first */
 257                 s = s + "%" + scope_ifname.getName();
 258             } else if (scope_id_set) {
 259                 s = s + "%" + scope_id;
 260             }
 261             return s;
 262         }
 263 
 264         public boolean equals(Object o) {
 265             if (! (o instanceof Inet6AddressHolder)) {
 266                 return false;
 267             }
 268             Inet6AddressHolder that = (Inet6AddressHolder)o;
 269 
 270             return Arrays.equals(this.ipaddress, that.ipaddress);
 271         }
 272 
 273         public int hashCode() {
 274             if (ipaddress != null) {
 275 
 276                 int hash = 0;
 277                 int i=0;
 278                 while (i<INADDRSZ) {
 279                     int j=0;
 280                     int component=0;
 281                     while (j<4 && i<INADDRSZ) {
 282                         component = (component << 8) + ipaddress[i];
 283                         j++;
 284                         i++;
 285                     }
 286                     hash += component;
 287                 }
 288                 return hash;
 289 
 290             } else {
 291                 return 0;
 292             }
 293         }
 294 
 295         boolean isIPv4CompatibleAddress() {
 296             if ((ipaddress[0] == 0x00) && (ipaddress[1] == 0x00) &&
 297                 (ipaddress[2] == 0x00) && (ipaddress[3] == 0x00) &&
 298                 (ipaddress[4] == 0x00) && (ipaddress[5] == 0x00) &&
 299                 (ipaddress[6] == 0x00) && (ipaddress[7] == 0x00) &&
 300                 (ipaddress[8] == 0x00) && (ipaddress[9] == 0x00) &&
 301                 (ipaddress[10] == 0x00) && (ipaddress[11] == 0x00))  {
 302                 return true;
 303             }
 304             return false;
 305         }
 306 
 307         boolean isMulticastAddress() {
 308             return ((ipaddress[0] & 0xff) == 0xff);
 309         }
 310 
 311         boolean isAnyLocalAddress() {
 312             byte test = 0x00;
 313             for (int i = 0; i < INADDRSZ; i++) {
 314                 test |= ipaddress[i];
 315             }
 316             return (test == 0x00);
 317         }
 318 
 319         boolean isLoopbackAddress() {
 320             byte test = 0x00;
 321             for (int i = 0; i < 15; i++) {
 322                 test |= ipaddress[i];
 323             }
 324             return (test == 0x00) && (ipaddress[15] == 0x01);
 325         }
 326 
 327         boolean isLinkLocalAddress() {
 328             return ((ipaddress[0] & 0xff) == 0xfe
 329                     && (ipaddress[1] & 0xc0) == 0x80);
 330         }
 331 
 332 
 333         boolean isSiteLocalAddress() {
 334             return ((ipaddress[0] & 0xff) == 0xfe
 335                     && (ipaddress[1] & 0xc0) == 0xc0);
 336         }
 337 
 338         boolean isMCGlobal() {
 339             return ((ipaddress[0] & 0xff) == 0xff
 340                     && (ipaddress[1] & 0x0f) == 0x0e);
 341         }
 342 
 343         boolean isMCNodeLocal() {
 344             return ((ipaddress[0] & 0xff) == 0xff
 345                     && (ipaddress[1] & 0x0f) == 0x01);
 346         }
 347 
 348         boolean isMCLinkLocal() {
 349             return ((ipaddress[0] & 0xff) == 0xff
 350                     && (ipaddress[1] & 0x0f) == 0x02);
 351         }
 352 
 353         boolean isMCSiteLocal() {
 354             return ((ipaddress[0] & 0xff) == 0xff
 355                     && (ipaddress[1] & 0x0f) == 0x05);
 356         }
 357 
 358         boolean isMCOrgLocal() {
 359             return ((ipaddress[0] & 0xff) == 0xff
 360                     && (ipaddress[1] & 0x0f) == 0x08);
 361         }
 362     }
 363 
 364     private final transient Inet6AddressHolder holder6;
 365 
 366     @java.io.Serial
 367     private static final long serialVersionUID = 6880410070516793377L;
 368 
 369     // Perform native initialization
 370     static { init(); }
 371 
 372     Inet6Address() {
 373         super();
 374         holder.init(null, IPv6);
 375         holder6 = new Inet6AddressHolder();
 376     }
 377 
 378     /* checking of value for scope_id should be done by caller
 379      * scope_id must be >= 0, or -1 to indicate not being set
 380      */
 381     Inet6Address(String hostName, byte addr[], int scope_id) {
 382         holder.init(hostName, IPv6);
 383         holder6 = new Inet6AddressHolder();
 384         holder6.init(addr, scope_id);
 385     }
 386 
 387     Inet6Address(String hostName, byte addr[]) {
 388         holder6 = new Inet6AddressHolder();
 389         try {
 390             initif (hostName, addr, null);
 391         } catch (UnknownHostException e) {} /* cant happen if ifname is null */
 392     }
 393 
 394     Inet6Address (String hostName, byte addr[], NetworkInterface nif)
 395         throws UnknownHostException
 396     {
 397         holder6 = new Inet6AddressHolder();
 398         initif (hostName, addr, nif);
 399     }
 400 
 401     Inet6Address (String hostName, byte addr[], String ifname)
 402         throws UnknownHostException
 403     {
 404         holder6 = new Inet6AddressHolder();
 405         initstr (hostName, addr, ifname);
 406     }
 407 
 408     /**
 409      * Create an Inet6Address in the exact manner of {@link
 410      * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is
 411      * set to the value corresponding to the given interface for the address
 412      * type specified in {@code addr}. The call will fail with an
 413      * UnknownHostException if the given interface does not have a numeric
 414      * scope_id assigned for the given address type (e.g. link-local or site-local).
 415      * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
 416      * scoped addresses.
 417      *
 418      * @param host the specified host
 419      * @param addr the raw IP address in network byte order
 420      * @param nif an interface this address must be associated with.
 421      * @return  an Inet6Address object created from the raw IP address.
 422      * @throws  UnknownHostException
 423      *          if IP address is of illegal length, or if the interface does not
 424      *          have a numeric scope_id assigned for the given address type.
 425      *
 426      * @since 1.5
 427      */
 428     public static Inet6Address getByAddress(String host, byte[] addr,
 429                                             NetworkInterface nif)
 430         throws UnknownHostException
 431     {
 432         if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
 433             if (host.charAt(host.length()-1) == ']') {
 434                 host = host.substring(1, host.length() -1);
 435             }
 436         }
 437         if (addr != null) {
 438             if (addr.length == Inet6Address.INADDRSZ) {
 439                 return new Inet6Address(host, addr, nif);
 440             }
 441         }
 442         throw new UnknownHostException("addr is of illegal length");
 443     }
 444 
 445     /**
 446      * Create an Inet6Address in the exact manner of {@link
 447      * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is
 448      * set to the given numeric value. The scope_id is not checked to determine
 449      * if it corresponds to any interface on the system.
 450      * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
 451      * scoped addresses.
 452      *
 453      * @param host the specified host
 454      * @param addr the raw IP address in network byte order
 455      * @param scope_id the numeric scope_id for the address.
 456      * @return  an Inet6Address object created from the raw IP address.
 457      * @throws  UnknownHostException  if IP address is of illegal length.
 458      *
 459      * @since 1.5
 460      */
 461     public static Inet6Address getByAddress(String host, byte[] addr,
 462                                             int scope_id)
 463         throws UnknownHostException
 464     {
 465         if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
 466             if (host.charAt(host.length()-1) == ']') {
 467                 host = host.substring(1, host.length() -1);
 468             }
 469         }
 470         if (addr != null) {
 471             if (addr.length == Inet6Address.INADDRSZ) {
 472                 return new Inet6Address(host, addr, scope_id);
 473             }
 474         }
 475         throw new UnknownHostException("addr is of illegal length");
 476     }
 477 
 478     private void initstr(String hostName, byte addr[], String ifname)
 479         throws UnknownHostException
 480     {
 481         try {
 482             NetworkInterface nif = NetworkInterface.getByName (ifname);
 483             if (nif == null) {
 484                 throw new UnknownHostException ("no such interface " + ifname);
 485             }
 486             initif (hostName, addr, nif);
 487         } catch (SocketException e) {
 488             throw new UnknownHostException ("SocketException thrown" + ifname);
 489         }
 490     }
 491 
 492     private void initif(String hostName, byte addr[], NetworkInterface nif)
 493         throws UnknownHostException
 494     {
 495         int family = -1;
 496         holder6.init(addr, nif);
 497 
 498         if (addr.length == INADDRSZ) { // normal IPv6 address
 499             family = IPv6;
 500         }
 501         holder.init(hostName, family);
 502     }
 503 
 504     /* check the two Ipv6 addresses and return false if they are both
 505      * non global address types, but not the same.
 506      * (i.e. one is site-local and the other link-local)
 507      * return true otherwise.
 508      */
 509 
 510     private static boolean isDifferentLocalAddressType(
 511         byte[] thisAddr, byte[] otherAddr) {
 512 
 513         if (Inet6Address.isLinkLocalAddress(thisAddr) &&
 514                 !Inet6Address.isLinkLocalAddress(otherAddr)) {
 515             return false;
 516         }
 517         if (Inet6Address.isSiteLocalAddress(thisAddr) &&
 518                 !Inet6Address.isSiteLocalAddress(otherAddr)) {
 519             return false;
 520         }
 521         return true;
 522     }
 523 
 524     private static int deriveNumericScope (byte[] thisAddr, NetworkInterface ifc) throws UnknownHostException {
 525         Enumeration<InetAddress> addresses = ifc.getInetAddresses();
 526         while (addresses.hasMoreElements()) {
 527             InetAddress addr = addresses.nextElement();
 528             if (!(addr instanceof Inet6Address)) {
 529                 continue;
 530             }
 531             Inet6Address ia6_addr = (Inet6Address)addr;
 532             /* check if site or link local prefixes match */
 533             if (!isDifferentLocalAddressType(thisAddr, ia6_addr.getAddress())){
 534                 /* type not the same, so carry on searching */
 535                 continue;
 536             }
 537             /* found a matching address - return its scope_id */
 538             return ia6_addr.getScopeId();
 539         }
 540         throw new UnknownHostException ("no scope_id found");
 541     }
 542 
 543     private int deriveNumericScope (String ifname) throws UnknownHostException {
 544         Enumeration<NetworkInterface> en;
 545         try {
 546             en = NetworkInterface.getNetworkInterfaces();
 547         } catch (SocketException e) {
 548             throw new UnknownHostException ("could not enumerate local network interfaces");
 549         }
 550         while (en.hasMoreElements()) {
 551             NetworkInterface ifc = en.nextElement();
 552             if (ifc.getName().equals (ifname)) {
 553                 return deriveNumericScope(holder6.ipaddress, ifc);
 554             }
 555         }
 556         throw new UnknownHostException ("No matching address found for interface : " +ifname);
 557     }
 558 
 559     /**
 560      * @serialField ipaddress byte[]
 561      * @serialField scope_id int
 562      * @serialField scope_id_set boolean
 563      * @serialField scope_ifname_set boolean
 564      * @serialField ifname String
 565      */
 566     @java.io.Serial
 567     private static final ObjectStreamField[] serialPersistentFields = {
 568          new ObjectStreamField("ipaddress", byte[].class),
 569          new ObjectStreamField("scope_id", int.class),
 570          new ObjectStreamField("scope_id_set", boolean.class),
 571          new ObjectStreamField("scope_ifname_set", boolean.class),
 572          new ObjectStreamField("ifname", String.class)
 573     };
 574 
 575     private static final jdk.internal.misc.Unsafe UNSAFE
 576             = jdk.internal.misc.Unsafe.getUnsafe();
 577     private static final long FIELDS_OFFSET = UNSAFE.objectFieldOffset(
 578                 Inet6Address.class, "holder6");
 579 
 580     /**
 581      * restore the state of this object from stream
 582      * including the scope information, only if the
 583      * scoped interface name is valid on this system
 584      */
 585     @java.io.Serial
 586     private void readObject(ObjectInputStream s)
 587         throws IOException, ClassNotFoundException {
 588         NetworkInterface scope_ifname = null;
 589 
 590         if (getClass().getClassLoader() != null) {
 591             throw new SecurityException ("invalid address type");
 592         }
 593 
 594         ObjectInputStream.GetField gf = s.readFields();
 595         byte[] ipaddress = (byte[])gf.get("ipaddress", new byte[0]);
 596         int scope_id = gf.get("scope_id", -1);
 597         boolean scope_id_set = gf.get("scope_id_set", false);
 598         boolean scope_ifname_set = gf.get("scope_ifname_set", false);
 599         String ifname = (String)gf.get("ifname", null);
 600 
 601         if (ifname != null && !ifname.isEmpty()) {
 602             try {
 603                 scope_ifname = NetworkInterface.getByName(ifname);
 604                 if (scope_ifname == null) {
 605                     /* the interface does not exist on this system, so we clear
 606                      * the scope information completely */
 607                     scope_id_set = false;
 608                     scope_ifname_set = false;
 609                     scope_id = 0;
 610                 } else {
 611                     scope_ifname_set = true;
 612                     try {
 613                         scope_id = deriveNumericScope (ipaddress, scope_ifname);
 614                     } catch (UnknownHostException e) {
 615                         // typically should not happen, but it may be that
 616                         // the machine being used for deserialization has
 617                         // the same interface name but without IPv6 configured.
 618                     }
 619                 }
 620             } catch (SocketException e) {}
 621         }
 622 
 623         /* if ifname was not supplied, then the numeric info is used */
 624 
 625         ipaddress = ipaddress.clone();
 626 
 627         // Check that our invariants are satisfied
 628         if (ipaddress.length != INADDRSZ) {
 629             throw new InvalidObjectException("invalid address length: "+
 630                                              ipaddress.length);
 631         }
 632 
 633         if (holder.getFamily() != IPv6) {
 634             throw new InvalidObjectException("invalid address family type");
 635         }
 636 
 637         Inet6AddressHolder h = new Inet6AddressHolder(
 638             ipaddress, scope_id, scope_id_set, scope_ifname, scope_ifname_set
 639         );
 640 
 641         UNSAFE.putReference(this, FIELDS_OFFSET, h);
 642     }
 643 
 644     /**
 645      * default behavior is overridden in order to write the
 646      * scope_ifname field as a String, rather than a NetworkInterface
 647      * which is not serializable
 648      */
 649     @java.io.Serial
 650     private synchronized void writeObject(ObjectOutputStream s)
 651         throws IOException
 652     {
 653             String ifname = null;
 654 
 655         if (holder6.scope_ifname != null) {
 656             ifname = holder6.scope_ifname.getName();
 657             holder6.scope_ifname_set = true;
 658         }
 659         ObjectOutputStream.PutField pfields = s.putFields();
 660         pfields.put("ipaddress", holder6.ipaddress);
 661         pfields.put("scope_id", holder6.scope_id);
 662         pfields.put("scope_id_set", holder6.scope_id_set);
 663         pfields.put("scope_ifname_set", holder6.scope_ifname_set);
 664         pfields.put("ifname", ifname);
 665         s.writeFields();
 666     }
 667 
 668     /**
 669      * Utility routine to check if the InetAddress is an IP multicast
 670      * address. 11111111 at the start of the address identifies the
 671      * address as being a multicast address.
 672      *
 673      * @return a {@code boolean} indicating if the InetAddress is an IP
 674      *         multicast address
 675      */
 676     @Override
 677     public boolean isMulticastAddress() {
 678         return holder6.isMulticastAddress();
 679     }
 680 
 681     /**
 682      * Utility routine to check if the InetAddress is a wildcard address.
 683      *
 684      * @return a {@code boolean} indicating if the InetAddress is
 685      *         a wildcard address.
 686      */
 687     @Override
 688     public boolean isAnyLocalAddress() {
 689         return holder6.isAnyLocalAddress();
 690     }
 691 
 692     /**
 693      * Utility routine to check if the InetAddress is a loopback address.
 694      *
 695      * @return a {@code boolean} indicating if the InetAddress is a loopback
 696      *         address; or false otherwise.
 697      */
 698     @Override
 699     public boolean isLoopbackAddress() {
 700         return holder6.isLoopbackAddress();
 701     }
 702 
 703     /**
 704      * Utility routine to check if the InetAddress is an link local address.
 705      *
 706      * @return a {@code boolean} indicating if the InetAddress is a link local
 707      *         address; or false if address is not a link local unicast address.
 708      */
 709     @Override
 710     public boolean isLinkLocalAddress() {
 711         return holder6.isLinkLocalAddress();
 712     }
 713 
 714     /* static version of above */
 715     static boolean isLinkLocalAddress(byte[] ipaddress) {
 716         return ((ipaddress[0] & 0xff) == 0xfe
 717                 && (ipaddress[1] & 0xc0) == 0x80);
 718     }
 719 
 720     /**
 721      * Utility routine to check if the InetAddress is a site local address.
 722      *
 723      * @return a {@code boolean} indicating if the InetAddress is a site local
 724      *         address; or false if address is not a site local unicast address.
 725      */
 726     @Override
 727     public boolean isSiteLocalAddress() {
 728         return holder6.isSiteLocalAddress();
 729     }
 730 
 731     /* static version of above */
 732     static boolean isSiteLocalAddress(byte[] ipaddress) {
 733         return ((ipaddress[0] & 0xff) == 0xfe
 734                 && (ipaddress[1] & 0xc0) == 0xc0);
 735     }
 736 
 737     /**
 738      * Utility routine to check if the multicast address has global scope.
 739      *
 740      * @return a {@code boolean} indicating if the address has is a multicast
 741      *         address of global scope, false if it is not of global scope or
 742      *         it is not a multicast address
 743      */
 744     @Override
 745     public boolean isMCGlobal() {
 746         return holder6.isMCGlobal();
 747     }
 748 
 749     /**
 750      * Utility routine to check if the multicast address has node scope.
 751      *
 752      * @return a {@code boolean} indicating if the address has is a multicast
 753      *         address of node-local scope, false if it is not of node-local
 754      *         scope or it is not a multicast address
 755      */
 756     @Override
 757     public boolean isMCNodeLocal() {
 758         return holder6.isMCNodeLocal();
 759     }
 760 
 761     /**
 762      * Utility routine to check if the multicast address has link scope.
 763      *
 764      * @return a {@code boolean} indicating if the address has is a multicast
 765      *         address of link-local scope, false if it is not of link-local
 766      *         scope or it is not a multicast address
 767      */
 768     @Override
 769     public boolean isMCLinkLocal() {
 770         return holder6.isMCLinkLocal();
 771     }
 772 
 773     /**
 774      * Utility routine to check if the multicast address has site scope.
 775      *
 776      * @return a {@code boolean} indicating if the address has is a multicast
 777      *         address of site-local scope, false if it is not  of site-local
 778      *         scope or it is not a multicast address
 779      */
 780     @Override
 781     public boolean isMCSiteLocal() {
 782         return holder6.isMCSiteLocal();
 783     }
 784 
 785     /**
 786      * Utility routine to check if the multicast address has organization scope.
 787      *
 788      * @return a {@code boolean} indicating if the address has is a multicast
 789      *         address of organization-local scope, false if it is not of
 790      *         organization-local scope or it is not a multicast address
 791      */
 792     @Override
 793     public boolean isMCOrgLocal() {
 794         return holder6.isMCOrgLocal();
 795     }
 796     /**
 797      * Returns the raw IP address of this {@code InetAddress} object. The result
 798      * is in network byte order: the highest order byte of the address is in
 799      * {@code getAddress()[0]}.
 800      *
 801      * @return  the raw IP address of this object.
 802      */
 803     @Override
 804     public byte[] getAddress() {
 805         return holder6.ipaddress.clone();
 806     }
 807 
 808     /**
 809      * Returns the numeric scopeId, if this instance is associated with
 810      * an interface. If no scoped_id is set, the returned value is zero.
 811      *
 812      * @return the scopeId, or zero if not set.
 813      *
 814      * @since 1.5
 815      */
 816      public int getScopeId() {
 817         return holder6.scope_id;
 818      }
 819 
 820     /**
 821      * Returns the scoped interface, if this instance was created with
 822      * a scoped interface.
 823      *
 824      * @return the scoped interface, or null if not set.
 825      * @since 1.5
 826      */
 827      public NetworkInterface getScopedInterface() {
 828         return holder6.scope_ifname;
 829      }
 830 
 831     /**
 832      * Returns the IP address string in textual presentation. If the instance
 833      * was created specifying a scope identifier then the scope id is appended
 834      * to the IP address preceded by a "%" (per-cent) character. This can be
 835      * either a numeric value or a string, depending on which was used to create
 836      * the instance.
 837      *
 838      * @return  the raw IP address in a string format.
 839      */
 840     @Override
 841     public String getHostAddress() {
 842         return holder6.getHostAddress();
 843     }
 844 
 845     /**
 846      * Returns a hashcode for this IP address.
 847      *
 848      * @return  a hash code value for this IP address.
 849      */
 850     @Override
 851     public int hashCode() {
 852         return holder6.hashCode();
 853     }
 854 
 855     /**
 856      * Compares this object against the specified object. The result is {@code
 857      * true} if and only if the argument is not {@code null} and it represents
 858      * the same IP address as this object.
 859      *
 860      * <p> Two instances of {@code InetAddress} represent the same IP address
 861      * if the length of the byte arrays returned by {@code getAddress} is the
 862      * same for both, and each of the array components is the same for the byte
 863      * arrays.
 864      *
 865      * @param   obj   the object to compare against.
 866      *
 867      * @return  {@code true} if the objects are the same; {@code false} otherwise.
 868      *
 869      * @see     java.net.InetAddress#getAddress()
 870      */
 871     @Override
 872     public boolean equals(Object obj) {
 873         if (obj == null || !(obj instanceof Inet6Address))
 874             return false;
 875 
 876         Inet6Address inetAddr = (Inet6Address)obj;
 877 
 878         return holder6.equals(inetAddr.holder6);
 879     }
 880 
 881     /**
 882      * Utility routine to check if the InetAddress is an
 883      * IPv4 compatible IPv6 address.
 884      *
 885      * @return a {@code boolean} indicating if the InetAddress is an IPv4
 886      *         compatible IPv6 address; or false if address is IPv4 address.
 887      */
 888     public boolean isIPv4CompatibleAddress() {
 889         return holder6.isIPv4CompatibleAddress();
 890     }
 891 
 892     // Utilities
 893 
 894     private static final int INT16SZ = 2;
 895 
 896     /**
 897      * Convert IPv6 binary address into presentation (printable) format.
 898      *
 899      * @param src a byte array representing the IPv6 numeric address
 900      * @return a String representing an IPv6 address in
 901      *         textual representation format
 902      */
 903     static String numericToTextFormat(byte[] src) {
 904         StringBuilder sb = new StringBuilder(39);
 905         for (int i = 0; i < (INADDRSZ / INT16SZ); i++) {
 906             sb.append(Integer.toHexString(((src[i<<1]<<8) & 0xff00)
 907                                           | (src[(i<<1)+1] & 0xff)));
 908             if (i < (INADDRSZ / INT16SZ) -1 ) {
 909                sb.append(":");
 910             }
 911         }
 912         return sb.toString();
 913     }
 914 
 915     /**
 916      * Perform class load-time initializations.
 917      */
 918     private static native void init();
 919 }