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1   /*
2    * Copyright (c) 2000, 2013, 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   * <h3> <A NAME="format">Textual representation of IP addresses</a> </h3>
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 NAME="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><table cellpadding=0 cellspacing=0 summary="layout">
53   *   <tr><td>{@code 1080:0:0:0:8:800:200C:417A}<td></tr>
54   *   </table></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><table cellpadding=0 cellspacing=0 summary="layout">
70   *   <tr><td>{@code 1080::8:800:200C:417A}<td></tr>
71   *   </table></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><table cellpadding=0 cellspacing=0 summary="layout">
81   *   <tr><td>{@code ::FFFF:129.144.52.38}<td></tr>
82   *   <tr><td>{@code ::129.144.52.38}<td></tr>
83   *   </table></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><table cellpadding=0 cellspacing=0 summary="layout">
91   *   <tr><td>{@code ::FFFF:d.d.d}<td></tr>
92   *   <tr><td>{@code ::FFFF:d.d}<td></tr>
93   *   <tr><td>{@code ::d.d.d}<td></tr>
94   *   <tr><td>{@code ::d.d}<td></tr>
95   *   </table></blockquote>
96   *
97   *   <p> The following form:
98   *
99   *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
100  *   <tr><td>{@code ::FFFF:d}<td></tr>
101  *   </table></blockquote>
102  *
103  *   <p> is valid, however it is an unconventional representation of
104  *   the IPv4-compatible IPv6 address,
105  *
106  *   <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
107  *   <tr><td>{@code ::255.255.0.d}<td></tr>
108  *   </table></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  * <h4> Special IPv6 address </h4>
120  *
121  * <blockquote>
122  * <table cellspacing=2 summary="Description of IPv4-mapped address">
123  * <tr><th valign=top><i>IPv4-mapped address</i></th>
124  *         <td>Of the form::ffff:w.x.y.z, this IPv6 address is used to
125  *         represent an IPv4 address. It allows the native program to
126  *         use the same address data structure and also the same
127  *         socket when communicating with both IPv4 and IPv6 nodes.
128  *
129  *         <p>In InetAddress and Inet6Address, it is used for internal
130  *         representation; it has no functional role. Java will never
131  *         return an IPv4-mapped address.  These classes can take an
132  *         IPv4-mapped address as input, both in byte array and text
133  *         representation. However, it will be converted into an IPv4
134  *         address.</td></tr>
135  * </table></blockquote>
136  *
137  * <h4><A NAME="scoped">Textual representation of IPv6 scoped addresses</a></h4>
138  *
139  * <p> The textual representation of IPv6 addresses as described above can be
140  * extended to specify IPv6 scoped addresses. This extension to the basic
141  * addressing architecture is described in [draft-ietf-ipngwg-scoping-arch-04.txt].
142  *
143  * <p> Because link-local and site-local addresses are non-global, it is possible
144  * that different hosts may have the same destination address and may be
145  * reachable through different interfaces on the same originating system. In
146  * this case, the originating system is said to be connected to multiple zones
147  * of the same scope. In order to disambiguate which is the intended destination
148  * zone, it is possible to append a zone identifier (or <i>scope_id</i>) to an
149  * IPv6 address.
150  *
151  * <p> The general format for specifying the <i>scope_id</i> is the following:
152  *
153  * <blockquote><i>IPv6-address</i>%<i>scope_id</i></blockquote>
154  * <p> The IPv6-address is a literal IPv6 address as described above.
155  * The <i>scope_id</i> refers to an interface on the local system, and it can be
156  * specified in two ways.
157  * <ol><li><i>As a numeric identifier.</i> This must be a positive integer
158  * that identifies the particular interface and scope as understood by the
159  * system. Usually, the numeric values can be determined through administration
160  * tools on the system. Each interface may have multiple values, one for each
161  * scope. If the scope is unspecified, then the default value used is zero.</li>
162  * <li><i>As a string.</i> This must be the exact string that is returned by
163  * {@link java.net.NetworkInterface#getName()} for the particular interface in
164  * question. When an Inet6Address is created in this way, the numeric scope-id
165  * is determined at the time the object is created by querying the relevant
166  * NetworkInterface.</li></ol>
167  *
168  * <p> Note also, that the numeric <i>scope_id</i> can be retrieved from
169  * Inet6Address instances returned from the NetworkInterface class. This can be
170  * used to find out the current scope ids configured on the system.
171  * @since 1.4
172  */
173 
174 public final
175 class Inet6Address extends InetAddress {
176     final static int INADDRSZ = 16;
177 
178     /*
179      * cached scope_id - for link-local address use only.
180      */
181     private transient int cached_scope_id;  // 0
182 
183     private class Inet6AddressHolder {
184 
185         private Inet6AddressHolder() {
186             ipaddress = new byte[INADDRSZ];
187         }
188 
189         private Inet6AddressHolder(
190             byte[] ipaddress, int scope_id, boolean scope_id_set,
191             NetworkInterface ifname, boolean scope_ifname_set)
192         {
193             this.ipaddress = ipaddress;
194             this.scope_id = scope_id;
195             this.scope_id_set = scope_id_set;
196             this.scope_ifname_set = scope_ifname_set;
197             this.scope_ifname = ifname;
198         }
199 
200         /**
201          * Holds a 128-bit (16 bytes) IPv6 address.
202          */
203         byte[] ipaddress;
204 
205         /**
206          * scope_id. The scope specified when the object is created. If the object
207          * is created with an interface name, then the scope_id is not determined
208          * until the time it is needed.
209          */
210         int scope_id;  // 0
211 
212         /**
213          * This will be set to true when the scope_id field contains a valid
214          * integer scope_id.
215          */
216         boolean scope_id_set;  // false
217 
218         /**
219          * scoped interface. scope_id is derived from this as the scope_id of the first
220          * address whose scope is the same as this address for the named interface.
221          */
222         NetworkInterface scope_ifname;  // null
223 
224         /**
225          * set if the object is constructed with a scoped
226          * interface instead of a numeric scope id.
227          */
228         boolean scope_ifname_set; // false;
229 
230         void setAddr(byte addr[]) {
231             if (addr.length == INADDRSZ) { // normal IPv6 address
232                 System.arraycopy(addr, 0, ipaddress, 0, INADDRSZ);
233             }
234         }
235 
236         void init(byte addr[], int scope_id) {
237             setAddr(addr);
238 
239             if (scope_id >= 0) {
240                 this.scope_id = scope_id;
241                 this.scope_id_set = true;
242             }
243         }
244 
245         void init(byte addr[], NetworkInterface nif)
246             throws UnknownHostException
247         {
248             setAddr(addr);
249 
250             if (nif != null) {
251                 this.scope_id = deriveNumericScope(ipaddress, nif);
252                 this.scope_id_set = true;
253                 this.scope_ifname = nif;
254                 this.scope_ifname_set = true;
255             }
256         }
257 
258         String getHostAddress() {
259             String s = numericToTextFormat(ipaddress);
260             if (scope_ifname != null) { /* must check this first */
261                 s = s + "%" + scope_ifname.getName();
262             } else if (scope_id_set) {
263                 s = s + "%" + scope_id;
264             }
265             return s;
266         }
267 
268         public boolean equals(Object o) {
269             if (! (o instanceof Inet6AddressHolder)) {
270                 return false;
271             }
272             Inet6AddressHolder that = (Inet6AddressHolder)o;
273 
274             return Arrays.equals(this.ipaddress, that.ipaddress);
275         }
276 
277         public int hashCode() {
278             if (ipaddress != null) {
279 
280                 int hash = 0;
281                 int i=0;
282                 while (i<INADDRSZ) {
283                     int j=0;
284                     int component=0;
285                     while (j<4 && i<INADDRSZ) {
286                         component = (component << 8) + ipaddress[i];
287                         j++;
288                         i++;
289                     }
290                     hash += component;
291                 }
292                 return hash;
293 
294             } else {
295                 return 0;
296             }
297         }
298 
299         boolean isIPv4CompatibleAddress() {
300             if ((ipaddress[0] == 0x00) && (ipaddress[1] == 0x00) &&
301                 (ipaddress[2] == 0x00) && (ipaddress[3] == 0x00) &&
302                 (ipaddress[4] == 0x00) && (ipaddress[5] == 0x00) &&
303                 (ipaddress[6] == 0x00) && (ipaddress[7] == 0x00) &&
304                 (ipaddress[8] == 0x00) && (ipaddress[9] == 0x00) &&
305                 (ipaddress[10] == 0x00) && (ipaddress[11] == 0x00))  {
306                 return true;
307             }
308             return false;
309         }
310 
311         boolean isMulticastAddress() {
312             return ((ipaddress[0] & 0xff) == 0xff);
313         }
314 
315         boolean isAnyLocalAddress() {
316             byte test = 0x00;
317             for (int i = 0; i < INADDRSZ; i++) {
318                 test |= ipaddress[i];
319             }
320             return (test == 0x00);
321         }
322 
323         boolean isLoopbackAddress() {
324             byte test = 0x00;
325             for (int i = 0; i < 15; i++) {
326                 test |= ipaddress[i];
327             }
328             return (test == 0x00) && (ipaddress[15] == 0x01);
329         }
330 
331         boolean isLinkLocalAddress() {
332             return ((ipaddress[0] & 0xff) == 0xfe
333                     && (ipaddress[1] & 0xc0) == 0x80);
334         }
335 
336 
337         boolean isSiteLocalAddress() {
338             return ((ipaddress[0] & 0xff) == 0xfe
339                     && (ipaddress[1] & 0xc0) == 0xc0);
340         }
341 
342         boolean isMCGlobal() {
343             return ((ipaddress[0] & 0xff) == 0xff
344                     && (ipaddress[1] & 0x0f) == 0x0e);
345         }
346 
347         boolean isMCNodeLocal() {
348             return ((ipaddress[0] & 0xff) == 0xff
349                     && (ipaddress[1] & 0x0f) == 0x01);
350         }
351 
352         boolean isMCLinkLocal() {
353             return ((ipaddress[0] & 0xff) == 0xff
354                     && (ipaddress[1] & 0x0f) == 0x02);
355         }
356 
357         boolean isMCSiteLocal() {
358             return ((ipaddress[0] & 0xff) == 0xff
359                     && (ipaddress[1] & 0x0f) == 0x05);
360         }
361 
362         boolean isMCOrgLocal() {
363             return ((ipaddress[0] & 0xff) == 0xff
364                     && (ipaddress[1] & 0x0f) == 0x08);
365         }
366     }
367 
368     private final transient Inet6AddressHolder holder6;
369 
370     private static final long serialVersionUID = 6880410070516793377L;
371 
372     // Perform native initialization
373     static { init(); }
374 
375     Inet6Address() {
376         super();
377         holder.init(null, IPv6);
378         holder6 = new Inet6AddressHolder();
379     }
380 
381     /* checking of value for scope_id should be done by caller
382      * scope_id must be >= 0, or -1 to indicate not being set
383      */
384     Inet6Address(String hostName, byte addr[], int scope_id) {
385         holder.init(hostName, IPv6);
386         holder6 = new Inet6AddressHolder();
387         holder6.init(addr, scope_id);
388     }
389 
390     Inet6Address(String hostName, byte addr[]) {
391         holder6 = new Inet6AddressHolder();
392         try {
393             initif (hostName, addr, null);
394         } catch (UnknownHostException e) {} /* cant happen if ifname is null */
395     }
396 
397     Inet6Address (String hostName, byte addr[], NetworkInterface nif)
398         throws UnknownHostException
399     {
400         holder6 = new Inet6AddressHolder();
401         initif (hostName, addr, nif);
402     }
403 
404     Inet6Address (String hostName, byte addr[], String ifname)
405         throws UnknownHostException
406     {
407         holder6 = new Inet6AddressHolder();
408         initstr (hostName, addr, ifname);
409     }
410 
411     /**
412      * Create an Inet6Address in the exact manner of {@link
413      * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is
414      * set to the value corresponding to the given interface for the address
415      * type specified in {@code addr}. The call will fail with an
416      * UnknownHostException if the given interface does not have a numeric
417      * scope_id assigned for the given address type (eg. link-local or site-local).
418      * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
419      * scoped addresses.
420      *
421      * @param host the specified host
422      * @param addr the raw IP address in network byte order
423      * @param nif an interface this address must be associated with.
424      * @return  an Inet6Address object created from the raw IP address.
425      * @throws  UnknownHostException
426      *          if IP address is of illegal length, or if the interface does not
427      *          have a numeric scope_id assigned for the given address type.
428      *
429      * @since 1.5
430      */
431     public static Inet6Address getByAddress(String host, byte[] addr,
432                                             NetworkInterface nif)
433         throws UnknownHostException
434     {
435         if (host != null && host.length() > 0 && host.charAt(0) == '[') {
436             if (host.charAt(host.length()-1) == ']') {
437                 host = host.substring(1, host.length() -1);
438             }
439         }
440         if (addr != null) {
441             if (addr.length == Inet6Address.INADDRSZ) {
442                 return new Inet6Address(host, addr, nif);
443             }
444         }
445         throw new UnknownHostException("addr is of illegal length");
446     }
447 
448     /**
449      * Create an Inet6Address in the exact manner of {@link
450      * InetAddress#getByAddress(String,byte[])} except that the IPv6 scope_id is
451      * set to the given numeric value. The scope_id is not checked to determine
452      * if it corresponds to any interface on the system.
453      * See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
454      * scoped addresses.
455      *
456      * @param host the specified host
457      * @param addr the raw IP address in network byte order
458      * @param scope_id the numeric scope_id for the address.
459      * @return  an Inet6Address object created from the raw IP address.
460      * @throws  UnknownHostException  if IP address is of illegal length.
461      *
462      * @since 1.5
463      */
464     public static Inet6Address getByAddress(String host, byte[] addr,
465                                             int scope_id)
466         throws UnknownHostException
467     {
468         if (host != null && host.length() > 0 && host.charAt(0) == '[') {
469             if (host.charAt(host.length()-1) == ']') {
470                 host = host.substring(1, host.length() -1);
471             }
472         }
473         if (addr != null) {
474             if (addr.length == Inet6Address.INADDRSZ) {
475                 return new Inet6Address(host, addr, scope_id);
476             }
477         }
478         throw new UnknownHostException("addr is of illegal length");
479     }
480 
481     private void initstr(String hostName, byte addr[], String ifname)
482         throws UnknownHostException
483     {
484         try {
485             NetworkInterface nif = NetworkInterface.getByName (ifname);
486             if (nif == null) {
487                 throw new UnknownHostException ("no such interface " + ifname);
488             }
489             initif (hostName, addr, nif);
490         } catch (SocketException e) {
491             throw new UnknownHostException ("SocketException thrown" + ifname);
492         }
493     }
494 
495     private void initif(String hostName, byte addr[], NetworkInterface nif)
496         throws UnknownHostException
497     {
498         int family = -1;
499         holder6.init(addr, nif);
500 
501         if (addr.length == INADDRSZ) { // normal IPv6 address
502             family = IPv6;
503         }
504         holder.init(hostName, family);
505     }
506 
507     /* check the two Ipv6 addresses and return false if they are both
508      * non global address types, but not the same.
509      * (ie. one is sitelocal and the other linklocal)
510      * return true otherwise.
511      */
512 
513     private static boolean isDifferentLocalAddressType(
514         byte[] thisAddr, byte[] otherAddr) {
515 
516         if (Inet6Address.isLinkLocalAddress(thisAddr) &&
517                 !Inet6Address.isLinkLocalAddress(otherAddr)) {
518             return false;
519         }
520         if (Inet6Address.isSiteLocalAddress(thisAddr) &&
521                 !Inet6Address.isSiteLocalAddress(otherAddr)) {
522             return false;
523         }
524         return true;
525     }
526 
527     private static int deriveNumericScope (byte[] thisAddr, NetworkInterface ifc) throws UnknownHostException {
528         Enumeration<InetAddress> addresses = ifc.getInetAddresses();
529         while (addresses.hasMoreElements()) {
530             InetAddress addr = addresses.nextElement();
531             if (!(addr instanceof Inet6Address)) {
532                 continue;
533             }
534             Inet6Address ia6_addr = (Inet6Address)addr;
535             /* check if site or link local prefixes match */
536             if (!isDifferentLocalAddressType(thisAddr, ia6_addr.getAddress())){
537                 /* type not the same, so carry on searching */
538                 continue;
539             }
540             /* found a matching address - return its scope_id */
541             return ia6_addr.getScopeId();
542         }
543         throw new UnknownHostException ("no scope_id found");
544     }
545 
546     private int deriveNumericScope (String ifname) throws UnknownHostException {
547         Enumeration<NetworkInterface> en;
548         try {
549             en = NetworkInterface.getNetworkInterfaces();
550         } catch (SocketException e) {
551             throw new UnknownHostException ("could not enumerate local network interfaces");
552         }
553         while (en.hasMoreElements()) {
554             NetworkInterface ifc = en.nextElement();
555             if (ifc.getName().equals (ifname)) {
556                 return deriveNumericScope(holder6.ipaddress, ifc);
557             }
558         }
559         throw new UnknownHostException ("No matching address found for interface : " +ifname);
560     }
561 
562     /**
563      * @serialField ipaddress byte[]
564      * @serialField scope_id int
565      * @serialField scope_id_set boolean
566      * @serialField scope_ifname_set boolean
567      * @serialField ifname String
568      */
569 
570     private static final ObjectStreamField[] serialPersistentFields = {
571          new ObjectStreamField("ipaddress", byte[].class),
572          new ObjectStreamField("scope_id", int.class),
573          new ObjectStreamField("scope_id_set", boolean.class),
574          new ObjectStreamField("scope_ifname_set", boolean.class),
575          new ObjectStreamField("ifname", String.class)
576     };
577 
578     private static final long FIELDS_OFFSET;
579     private static final sun.misc.Unsafe UNSAFE;
580 
581     static {
582         try {
583             sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
584             FIELDS_OFFSET = unsafe.objectFieldOffset(
585                     Inet6Address.class.getDeclaredField("holder6"));
586             UNSAFE = unsafe;
587         } catch (ReflectiveOperationException e) {
588             throw new Error(e);
589         }
590     }
591 
592     /**
593      * restore the state of this object from stream
594      * including the scope information, only if the
595      * scoped interface name is valid on this system
596      */
597     private void readObject(ObjectInputStream s)
598         throws IOException, ClassNotFoundException {
599         NetworkInterface scope_ifname = null;
600 
601         if (getClass().getClassLoader() != null) {
602             throw new SecurityException ("invalid address type");
603         }
604 
605         ObjectInputStream.GetField gf = s.readFields();
606         byte[] ipaddress = (byte[])gf.get("ipaddress", null);
607         int scope_id = (int)gf.get("scope_id", -1);
608         boolean scope_id_set = (boolean)gf.get("scope_id_set", false);
609         boolean scope_ifname_set = (boolean)gf.get("scope_ifname_set", false);
610         String ifname = (String)gf.get("ifname", null);
611 
612         if (ifname != null && !"".equals (ifname)) {
613             try {
614                 scope_ifname = NetworkInterface.getByName(ifname);
615                 if (scope_ifname == null) {
616                     /* the interface does not exist on this system, so we clear
617                      * the scope information completely */
618                     scope_id_set = false;
619                     scope_ifname_set = false;
620                     scope_id = 0;
621                 } else {
622                     scope_ifname_set = true;
623                     try {
624                         scope_id = deriveNumericScope (ipaddress, scope_ifname);
625                     } catch (UnknownHostException e) {
626                         // typically should not happen, but it may be that
627                         // the machine being used for deserialization has
628                         // the same interface name but without IPv6 configured.
629                     }
630                 }
631             } catch (SocketException e) {}
632         }
633 
634         /* if ifname was not supplied, then the numeric info is used */
635 
636         ipaddress = ipaddress.clone();
637 
638         // Check that our invariants are satisfied
639         if (ipaddress.length != INADDRSZ) {
640             throw new InvalidObjectException("invalid address length: "+
641                                              ipaddress.length);
642         }
643 
644         if (holder.getFamily() != IPv6) {
645             throw new InvalidObjectException("invalid address family type");
646         }
647 
648         Inet6AddressHolder h = new Inet6AddressHolder(
649             ipaddress, scope_id, scope_id_set, scope_ifname, scope_ifname_set
650         );
651 
652         UNSAFE.putObject(this, FIELDS_OFFSET, h);
653     }
654 
655     /**
656      * default behavior is overridden in order to write the
657      * scope_ifname field as a String, rather than a NetworkInterface
658      * which is not serializable
659      */
660     private synchronized void writeObject(ObjectOutputStream s)
661         throws IOException
662     {
663             String ifname = null;
664 
665         if (holder6.scope_ifname != null) {
666             ifname = holder6.scope_ifname.getName();
667             holder6.scope_ifname_set = true;
668         }
669         ObjectOutputStream.PutField pfields = s.putFields();
670         pfields.put("ipaddress", holder6.ipaddress);
671         pfields.put("scope_id", holder6.scope_id);
672         pfields.put("scope_id_set", holder6.scope_id_set);
673         pfields.put("scope_ifname_set", holder6.scope_ifname_set);
674         pfields.put("ifname", ifname);
675         s.writeFields();
676     }
677 
678     /**
679      * Utility routine to check if the InetAddress is an IP multicast
680      * address. 11111111 at the start of the address identifies the
681      * address as being a multicast address.
682      *
683      * @return a {@code boolean} indicating if the InetAddress is an IP
684      *         multicast address
685      *
686      * @since JDK1.1
687      */
688     @Override
689     public boolean isMulticastAddress() {
690         return holder6.isMulticastAddress();
691     }
692 
693     /**
694      * Utility routine to check if the InetAddress in a wildcard address.
695      *
696      * @return a {@code boolean} indicating if the Inetaddress is
697      *         a wildcard address.
698      *
699      * @since 1.4
700      */
701     @Override
702     public boolean isAnyLocalAddress() {
703         return holder6.isAnyLocalAddress();
704     }
705 
706     /**
707      * Utility routine to check if the InetAddress is a loopback address.
708      *
709      * @return a {@code boolean} indicating if the InetAddress is a loopback
710      *         address; or false otherwise.
711      *
712      * @since 1.4
713      */
714     @Override
715     public boolean isLoopbackAddress() {
716         return holder6.isLoopbackAddress();
717     }
718 
719     /**
720      * Utility routine to check if the InetAddress is an link local address.
721      *
722      * @return a {@code boolean} indicating if the InetAddress is a link local
723      *         address; or false if address is not a link local unicast address.
724      *
725      * @since 1.4
726      */
727     @Override
728     public boolean isLinkLocalAddress() {
729         return holder6.isLinkLocalAddress();
730     }
731 
732     /* static version of above */
733     static boolean isLinkLocalAddress(byte[] ipaddress) {
734         return ((ipaddress[0] & 0xff) == 0xfe
735                 && (ipaddress[1] & 0xc0) == 0x80);
736     }
737 
738     /**
739      * Utility routine to check if the InetAddress is a site local address.
740      *
741      * @return a {@code boolean} indicating if the InetAddress is a site local
742      *         address; or false if address is not a site local unicast address.
743      *
744      * @since 1.4
745      */
746     @Override
747     public boolean isSiteLocalAddress() {
748         return holder6.isSiteLocalAddress();
749     }
750 
751     /* static version of above */
752     static boolean isSiteLocalAddress(byte[] ipaddress) {
753         return ((ipaddress[0] & 0xff) == 0xfe
754                 && (ipaddress[1] & 0xc0) == 0xc0);
755     }
756 
757     /**
758      * Utility routine to check if the multicast address has global scope.
759      *
760      * @return a {@code boolean} indicating if the address has is a multicast
761      *         address of global scope, false if it is not of global scope or
762      *         it is not a multicast address
763      *
764      * @since 1.4
765      */
766     @Override
767     public boolean isMCGlobal() {
768         return holder6.isMCGlobal();
769     }
770 
771     /**
772      * Utility routine to check if the multicast address has node scope.
773      *
774      * @return a {@code boolean} indicating if the address has is a multicast
775      *         address of node-local scope, false if it is not of node-local
776      *         scope or it is not a multicast address
777      *
778      * @since 1.4
779      */
780     @Override
781     public boolean isMCNodeLocal() {
782         return holder6.isMCNodeLocal();
783     }
784 
785     /**
786      * Utility routine to check if the multicast address has link scope.
787      *
788      * @return a {@code boolean} indicating if the address has is a multicast
789      *         address of link-local scope, false if it is not of link-local
790      *         scope or it is not a multicast address
791      *
792      * @since 1.4
793      */
794     @Override
795     public boolean isMCLinkLocal() {
796         return holder6.isMCLinkLocal();
797     }
798 
799     /**
800      * Utility routine to check if the multicast address has site scope.
801      *
802      * @return a {@code boolean} indicating if the address has is a multicast
803      *         address of site-local scope, false if it is not  of site-local
804      *         scope or it is not a multicast address
805      *
806      * @since 1.4
807      */
808     @Override
809     public boolean isMCSiteLocal() {
810         return holder6.isMCSiteLocal();
811     }
812 
813     /**
814      * Utility routine to check if the multicast address has organization scope.
815      *
816      * @return a {@code boolean} indicating if the address has is a multicast
817      *         address of organization-local scope, false if it is not of
818      *         organization-local scope or it is not a multicast address
819      *
820      * @since 1.4
821      */
822     @Override
823     public boolean isMCOrgLocal() {
824         return holder6.isMCOrgLocal();
825     }
826     /**
827      * Returns the raw IP address of this {@code InetAddress} object. The result
828      * is in network byte order: the highest order byte of the address is in
829      * {@code getAddress()[0]}.
830      *
831      * @return  the raw IP address of this object.
832      */
833     @Override
834     public byte[] getAddress() {
835         return holder6.ipaddress.clone();
836     }
837 
838     /**
839      * Returns the numeric scopeId, if this instance is associated with
840      * an interface. If no scoped_id is set, the returned value is zero.
841      *
842      * @return the scopeId, or zero if not set.
843      *
844      * @since 1.5
845      */
846      public int getScopeId() {
847         return holder6.scope_id;
848      }
849 
850     /**
851      * Returns the scoped interface, if this instance was created with
852      * with a scoped interface.
853      *
854      * @return the scoped interface, or null if not set.
855      * @since 1.5
856      */
857      public NetworkInterface getScopedInterface() {
858         return holder6.scope_ifname;
859      }
860 
861     /**
862      * Returns the IP address string in textual presentation. If the instance
863      * was created specifying a scope identifier then the scope id is appended
864      * to the IP address preceded by a "%" (per-cent) character. This can be
865      * either a numeric value or a string, depending on which was used to create
866      * the instance.
867      *
868      * @return  the raw IP address in a string format.
869      */
870     @Override
871     public String getHostAddress() {
872         return holder6.getHostAddress();
873     }
874 
875     /**
876      * Returns a hashcode for this IP address.
877      *
878      * @return  a hash code value for this IP address.
879      */
880     @Override
881     public int hashCode() {
882         return holder6.hashCode();
883     }
884 
885     /**
886      * Compares this object against the specified object. The result is {@code
887      * true} if and only if the argument is not {@code null} and it represents
888      * the same IP address as this object.
889      *
890      * <p> Two instances of {@code InetAddress} represent the same IP address
891      * if the length of the byte arrays returned by {@code getAddress} is the
892      * same for both, and each of the array components is the same for the byte
893      * arrays.
894      *
895      * @param   obj   the object to compare against.
896      *
897      * @return  {@code true} if the objects are the same; {@code false} otherwise.
898      *
899      * @see     java.net.InetAddress#getAddress()
900      */
901     @Override
902     public boolean equals(Object obj) {
903         if (obj == null || !(obj instanceof Inet6Address))
904             return false;
905 
906         Inet6Address inetAddr = (Inet6Address)obj;
907 
908         return holder6.equals(inetAddr.holder6);
909     }
910 
911     /**
912      * Utility routine to check if the InetAddress is an
913      * IPv4 compatible IPv6 address.
914      *
915      * @return a {@code boolean} indicating if the InetAddress is an IPv4
916      *         compatible IPv6 address; or false if address is IPv4 address.
917      *
918      * @since 1.4
919      */
920     public boolean isIPv4CompatibleAddress() {
921         return holder6.isIPv4CompatibleAddress();
922     }
923 
924     // Utilities
925     private final static int INT16SZ = 2;
926 
927     /*
928      * Convert IPv6 binary address into presentation (printable) format.
929      *
930      * @param src a byte array representing the IPv6 numeric address
931      * @return a String representing an IPv6 address in
932      *         textual representation format
933      * @since 1.4
934      */
935     static String numericToTextFormat(byte[] src) {
936         StringBuilder sb = new StringBuilder(39);
937         for (int i = 0; i < (INADDRSZ / INT16SZ); i++) {
938             sb.append(Integer.toHexString(((src[i<<1]<<8) & 0xff00)
939                                           | (src[(i<<1)+1] & 0xff)));
940             if (i < (INADDRSZ / INT16SZ) -1 ) {
941                sb.append(":");
942             }
943         }
944         return sb.toString();
945     }
946 
947     /**
948      * Perform class load-time initializations.
949      */
950     private static native void init();
951 }