1 /*
2 * Copyright (c) 1995, 2017, 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.util.NavigableSet;
29 import java.util.ArrayList;
30 import java.util.Objects;
31 import java.util.Scanner;
32 import java.security.AccessController;
33 import java.io.File;
34 import java.io.FileNotFoundException;
35 import java.io.ObjectStreamException;
36 import java.io.ObjectStreamField;
37 import java.io.IOException;
38 import java.io.ObjectInputStream;
39 import java.io.ObjectInputStream.GetField;
40 import java.io.ObjectOutputStream;
41 import java.io.ObjectOutputStream.PutField;
42 import java.lang.annotation.Native;
43 import java.util.concurrent.ConcurrentHashMap;
44 import java.util.concurrent.ConcurrentMap;
45 import java.util.concurrent.ConcurrentSkipListSet;
46 import java.util.concurrent.atomic.AtomicLong;
47
48 import jdk.internal.misc.JavaNetInetAddressAccess;
49 import jdk.internal.misc.SharedSecrets;
50 import sun.security.action.*;
51 import sun.net.InetAddressCachePolicy;
52 import sun.net.util.IPAddressUtil;
53
54 /**
55 * This class represents an Internet Protocol (IP) address.
56 *
57 * <p> An IP address is either a 32-bit or 128-bit unsigned number
58 * used by IP, a lower-level protocol on which protocols like UDP and
59 * TCP are built. The IP address architecture is defined by <a
60 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790:
61 * Assigned Numbers</i></a>, <a
62 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918:
63 * Address Allocation for Private Internets</i></a>, <a
64 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365:
65 * Administratively Scoped IP Multicast</i></a>, and <a
66 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP
67 * Version 6 Addressing Architecture</i></a>. An instance of an
68 * InetAddress consists of an IP address and possibly its
69 * corresponding host name (depending on whether it is constructed
70 * with a host name or whether it has already done reverse host name
71 * resolution).
72 *
73 * <h3> Address types </h3>
74 *
75 * <table class="striped" style="margin-left:2em">
76 * <caption style="display:none">Description of unicast and multicast address types</caption>
77 * <thead>
78 * <tr><th scope="col">Address Type</th><th scope="col">Description</th></tr>
79 * </thead>
80 * <tbody>
81 * <tr><th scope="row" style="vertical-align:top">unicast</th>
82 * <td>An identifier for a single interface. A packet sent to
83 * a unicast address is delivered to the interface identified by
84 * that address.
85 *
86 * <p> The Unspecified Address -- Also called anylocal or wildcard
87 * address. It must never be assigned to any node. It indicates the
88 * absence of an address. One example of its use is as the target of
89 * bind, which allows a server to accept a client connection on any
90 * interface, in case the server host has multiple interfaces.
91 *
92 * <p> The <i>unspecified</i> address must not be used as
93 * the destination address of an IP packet.
94 *
95 * <p> The <i>Loopback</i> Addresses -- This is the address
96 * assigned to the loopback interface. Anything sent to this
97 * IP address loops around and becomes IP input on the local
98 * host. This address is often used when testing a
99 * client.</td></tr>
100 * <tr><th scope="row" style="vertical-align:top">multicast</th>
101 * <td>An identifier for a set of interfaces (typically belonging
102 * to different nodes). A packet sent to a multicast address is
103 * delivered to all interfaces identified by that address.</td></tr>
104 * </tbody>
105 * </table>
106 *
107 * <h4> IP address scope </h4>
108 *
109 * <p> <i>Link-local</i> addresses are designed to be used for addressing
110 * on a single link for purposes such as auto-address configuration,
111 * neighbor discovery, or when no routers are present.
112 *
113 * <p> <i>Site-local</i> addresses are designed to be used for addressing
114 * inside of a site without the need for a global prefix.
115 *
116 * <p> <i>Global</i> addresses are unique across the internet.
117 *
118 * <h4> Textual representation of IP addresses </h4>
119 *
120 * The textual representation of an IP address is address family specific.
121 *
122 * <p>
123 *
124 * For IPv4 address format, please refer to <A
125 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6
126 * address format, please refer to <A
127 * HREF="Inet6Address.html#format">Inet6Address#format</A>.
128 *
129 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of
130 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P>
131 *
132 * <h4> Host Name Resolution </h4>
133 *
134 * Host name-to-IP address <i>resolution</i> is accomplished through
135 * the use of a combination of local machine configuration information
136 * and network naming services such as the Domain Name System (DNS)
137 * and Network Information Service(NIS). The particular naming
138 * services(s) being used is by default the local machine configured
139 * one. For any host name, its corresponding IP address is returned.
140 *
141 * <p> <i>Reverse name resolution</i> means that for any IP address,
142 * the host associated with the IP address is returned.
143 *
144 * <p> The InetAddress class provides methods to resolve host names to
145 * their IP addresses and vice versa.
146 *
147 * <h4> InetAddress Caching </h4>
148 *
149 * The InetAddress class has a cache to store successful as well as
150 * unsuccessful host name resolutions.
151 *
152 * <p> By default, when a security manager is installed, in order to
153 * protect against DNS spoofing attacks,
154 * the result of positive host name resolutions are
155 * cached forever. When a security manager is not installed, the default
156 * behavior is to cache entries for a finite (implementation dependent)
157 * period of time. The result of unsuccessful host
158 * name resolution is cached for a very short period of time (10
159 * seconds) to improve performance.
160 *
161 * <p> If the default behavior is not desired, then a Java security property
162 * can be set to a different Time-to-live (TTL) value for positive
163 * caching. Likewise, a system admin can configure a different
164 * negative caching TTL value when needed.
165 *
166 * <p> Two Java security properties control the TTL values used for
167 * positive and negative host name resolution caching:
168 *
169 * <dl style="margin-left:2em">
170 * <dt><b>networkaddress.cache.ttl</b></dt>
171 * <dd>Indicates the caching policy for successful name lookups from
172 * the name service. The value is specified as an integer to indicate
173 * the number of seconds to cache the successful lookup. The default
174 * setting is to cache for an implementation specific period of time.
175 * <p>
176 * A value of -1 indicates "cache forever".
177 * </dd>
178 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt>
179 * <dd>Indicates the caching policy for un-successful name lookups
180 * from the name service. The value is specified as an integer to
181 * indicate the number of seconds to cache the failure for
182 * un-successful lookups.
183 * <p>
184 * A value of 0 indicates "never cache".
185 * A value of -1 indicates "cache forever".
186 * </dd>
187 * </dl>
188 *
189 * @author Chris Warth
190 * @see java.net.InetAddress#getByAddress(byte[])
191 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
192 * @see java.net.InetAddress#getAllByName(java.lang.String)
193 * @see java.net.InetAddress#getByName(java.lang.String)
194 * @see java.net.InetAddress#getLocalHost()
195 * @since 1.0
196 */
197 public
198 class InetAddress implements java.io.Serializable {
199
200 @Native static final int PREFER_IPV4_VALUE = 0;
201 @Native static final int PREFER_IPV6_VALUE = 1;
202 @Native static final int PREFER_SYSTEM_VALUE = 2;
203
204 /**
205 * Specify the address family: Internet Protocol, Version 4
206 * @since 1.4
207 */
208 @Native static final int IPv4 = 1;
209
210 /**
211 * Specify the address family: Internet Protocol, Version 6
212 * @since 1.4
213 */
214 @Native static final int IPv6 = 2;
215
216 /* Specify address family preference */
217 static transient final int preferIPv6Address;
218
219 static class InetAddressHolder {
220 /**
221 * Reserve the original application specified hostname.
222 *
223 * The original hostname is useful for domain-based endpoint
224 * identification (see RFC 2818 and RFC 6125). If an address
225 * was created with a raw IP address, a reverse name lookup
226 * may introduce endpoint identification security issue via
227 * DNS forging.
228 *
229 * Oracle JSSE provider is using this original hostname, via
230 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
231 *
232 * Note: May define a new public method in the future if necessary.
233 */
234 String originalHostName;
235
236 InetAddressHolder() {}
237
238 InetAddressHolder(String hostName, int address, int family) {
239 this.originalHostName = hostName;
240 this.hostName = hostName;
241 this.address = address;
242 this.family = family;
243 }
244
245 void init(String hostName, int family) {
246 this.originalHostName = hostName;
247 this.hostName = hostName;
248 if (family != -1) {
249 this.family = family;
250 }
251 }
252
253 String hostName;
254
255 String getHostName() {
256 return hostName;
257 }
258
259 String getOriginalHostName() {
260 return originalHostName;
261 }
262
263 /**
264 * Holds a 32-bit IPv4 address.
265 */
266 int address;
267
268 int getAddress() {
269 return address;
270 }
271
272 /**
273 * Specifies the address family type, for instance, '1' for IPv4
274 * addresses, and '2' for IPv6 addresses.
275 */
276 int family;
277
278 int getFamily() {
279 return family;
280 }
281 }
282
283 /* Used to store the serializable fields of InetAddress */
284 final transient InetAddressHolder holder;
285
286 InetAddressHolder holder() {
287 return holder;
288 }
289
290 /* Used to store the name service provider */
291 private static transient NameService nameService = null;
292
293 /* Used to store the best available hostname */
294 private transient String canonicalHostName = null;
295
296 /** use serialVersionUID from JDK 1.0.2 for interoperability */
297 private static final long serialVersionUID = 3286316764910316507L;
298
299 /*
300 * Load net library into runtime, and perform initializations.
301 */
302 static {
303 String str = java.security.AccessController.doPrivileged(
304 new GetPropertyAction("java.net.preferIPv6Addresses"));
305 if (str == null) {
306 preferIPv6Address = PREFER_IPV4_VALUE;
307 } else if (str.equalsIgnoreCase("true")) {
308 preferIPv6Address = PREFER_IPV6_VALUE;
309 } else if (str.equalsIgnoreCase("false")) {
310 preferIPv6Address = PREFER_IPV4_VALUE;
311 } else if (str.equalsIgnoreCase("system")) {
312 preferIPv6Address = PREFER_SYSTEM_VALUE;
313 } else {
314 preferIPv6Address = PREFER_IPV4_VALUE;
315 }
316 AccessController.doPrivileged(
317 new java.security.PrivilegedAction<>() {
318 public Void run() {
319 System.loadLibrary("net");
320 return null;
321 }
322 });
323 SharedSecrets.setJavaNetInetAddressAccess(
324 new JavaNetInetAddressAccess() {
325 public String getOriginalHostName(InetAddress ia) {
326 return ia.holder.getOriginalHostName();
327 }
328
329 public InetAddress getByName(String hostName,
330 InetAddress hostAddress)
331 throws UnknownHostException
332 {
333 return InetAddress.getByName(hostName, hostAddress);
334 }
335 }
336 );
337 init();
338 }
339
340 /**
341 * Constructor for the Socket.accept() method.
342 * This creates an empty InetAddress, which is filled in by
343 * the accept() method. This InetAddress, however, is not
344 * put in the address cache, since it is not created by name.
345 */
346 InetAddress() {
347 holder = new InetAddressHolder();
348 }
349
350 /**
351 * Replaces the de-serialized object with an Inet4Address object.
352 *
353 * @return the alternate object to the de-serialized object.
354 *
355 * @throws ObjectStreamException if a new object replacing this
356 * object could not be created
357 */
358 private Object readResolve() throws ObjectStreamException {
359 // will replace the deserialized 'this' object
360 return new Inet4Address(holder().getHostName(), holder().getAddress());
361 }
362
363 /**
364 * Utility routine to check if the InetAddress is an
365 * IP multicast address.
366 * @return a {@code boolean} indicating if the InetAddress is
367 * an IP multicast address
368 * @since 1.1
369 */
370 public boolean isMulticastAddress() {
371 return false;
372 }
373
374 /**
375 * Utility routine to check if the InetAddress is a wildcard address.
376 * @return a {@code boolean} indicating if the Inetaddress is
377 * a wildcard address.
378 * @since 1.4
379 */
380 public boolean isAnyLocalAddress() {
381 return false;
382 }
383
384 /**
385 * Utility routine to check if the InetAddress is a loopback address.
386 *
387 * @return a {@code boolean} indicating if the InetAddress is
388 * a loopback address; or false otherwise.
389 * @since 1.4
390 */
391 public boolean isLoopbackAddress() {
392 return false;
393 }
394
395 /**
396 * Utility routine to check if the InetAddress is an link local address.
397 *
398 * @return a {@code boolean} indicating if the InetAddress is
399 * a link local address; or false if address is not a link local unicast address.
400 * @since 1.4
401 */
402 public boolean isLinkLocalAddress() {
403 return false;
404 }
405
406 /**
407 * Utility routine to check if the InetAddress is a site local address.
408 *
409 * @return a {@code boolean} indicating if the InetAddress is
410 * a site local address; or false if address is not a site local unicast address.
411 * @since 1.4
412 */
413 public boolean isSiteLocalAddress() {
414 return false;
415 }
416
417 /**
418 * Utility routine to check if the multicast address has global scope.
419 *
420 * @return a {@code boolean} indicating if the address has
421 * is a multicast address of global scope, false if it is not
422 * of global scope or it is not a multicast address
423 * @since 1.4
424 */
425 public boolean isMCGlobal() {
426 return false;
427 }
428
429 /**
430 * Utility routine to check if the multicast address has node scope.
431 *
432 * @return a {@code boolean} indicating if the address has
433 * is a multicast address of node-local scope, false if it is not
434 * of node-local scope or it is not a multicast address
435 * @since 1.4
436 */
437 public boolean isMCNodeLocal() {
438 return false;
439 }
440
441 /**
442 * Utility routine to check if the multicast address has link scope.
443 *
444 * @return a {@code boolean} indicating if the address has
445 * is a multicast address of link-local scope, false if it is not
446 * of link-local scope or it is not a multicast address
447 * @since 1.4
448 */
449 public boolean isMCLinkLocal() {
450 return false;
451 }
452
453 /**
454 * Utility routine to check if the multicast address has site scope.
455 *
456 * @return a {@code boolean} indicating if the address has
457 * is a multicast address of site-local scope, false if it is not
458 * of site-local scope or it is not a multicast address
459 * @since 1.4
460 */
461 public boolean isMCSiteLocal() {
462 return false;
463 }
464
465 /**
466 * Utility routine to check if the multicast address has organization scope.
467 *
468 * @return a {@code boolean} indicating if the address has
469 * is a multicast address of organization-local scope,
470 * false if it is not of organization-local scope
471 * or it is not a multicast address
472 * @since 1.4
473 */
474 public boolean isMCOrgLocal() {
475 return false;
476 }
477
478
479 /**
480 * Test whether that address is reachable. Best effort is made by the
481 * implementation to try to reach the host, but firewalls and server
482 * configuration may block requests resulting in a unreachable status
483 * while some specific ports may be accessible.
484 * A typical implementation will use ICMP ECHO REQUESTs if the
485 * privilege can be obtained, otherwise it will try to establish
486 * a TCP connection on port 7 (Echo) of the destination host.
487 * <p>
488 * The timeout value, in milliseconds, indicates the maximum amount of time
489 * the try should take. If the operation times out before getting an
490 * answer, the host is deemed unreachable. A negative value will result
491 * in an IllegalArgumentException being thrown.
492 *
493 * @param timeout the time, in milliseconds, before the call aborts
494 * @return a {@code boolean} indicating if the address is reachable.
495 * @throws IOException if a network error occurs
496 * @throws IllegalArgumentException if {@code timeout} is negative.
497 * @since 1.5
498 */
499 public boolean isReachable(int timeout) throws IOException {
500 return isReachable(null, 0 , timeout);
501 }
502
503 /**
504 * Test whether that address is reachable. Best effort is made by the
505 * implementation to try to reach the host, but firewalls and server
506 * configuration may block requests resulting in a unreachable status
507 * while some specific ports may be accessible.
508 * A typical implementation will use ICMP ECHO REQUESTs if the
509 * privilege can be obtained, otherwise it will try to establish
510 * a TCP connection on port 7 (Echo) of the destination host.
511 * <p>
512 * The {@code network interface} and {@code ttl} parameters
513 * let the caller specify which network interface the test will go through
514 * and the maximum number of hops the packets should go through.
515 * A negative value for the {@code ttl} will result in an
516 * IllegalArgumentException being thrown.
517 * <p>
518 * The timeout value, in milliseconds, indicates the maximum amount of time
519 * the try should take. If the operation times out before getting an
520 * answer, the host is deemed unreachable. A negative value will result
521 * in an IllegalArgumentException being thrown.
522 *
523 * @param netif the NetworkInterface through which the
524 * test will be done, or null for any interface
525 * @param ttl the maximum numbers of hops to try or 0 for the
526 * default
527 * @param timeout the time, in milliseconds, before the call aborts
528 * @throws IllegalArgumentException if either {@code timeout}
529 * or {@code ttl} are negative.
530 * @return a {@code boolean}indicating if the address is reachable.
531 * @throws IOException if a network error occurs
532 * @since 1.5
533 */
534 public boolean isReachable(NetworkInterface netif, int ttl,
535 int timeout) throws IOException {
536 if (ttl < 0)
537 throw new IllegalArgumentException("ttl can't be negative");
538 if (timeout < 0)
539 throw new IllegalArgumentException("timeout can't be negative");
540
541 return impl.isReachable(this, timeout, netif, ttl);
542 }
543
544 /**
545 * Gets the host name for this IP address.
546 *
547 * <p>If this InetAddress was created with a host name,
548 * this host name will be remembered and returned;
549 * otherwise, a reverse name lookup will be performed
550 * and the result will be returned based on the system
551 * configured name lookup service. If a lookup of the name service
552 * is required, call
553 * {@link #getCanonicalHostName() getCanonicalHostName}.
554 *
555 * <p>If there is a security manager, its
556 * {@code checkConnect} method is first called
557 * with the hostname and {@code -1}
558 * as its arguments to see if the operation is allowed.
559 * If the operation is not allowed, it will return
560 * the textual representation of the IP address.
561 *
562 * @return the host name for this IP address, or if the operation
563 * is not allowed by the security check, the textual
564 * representation of the IP address.
565 *
566 * @see InetAddress#getCanonicalHostName
567 * @see SecurityManager#checkConnect
568 */
569 public String getHostName() {
570 return getHostName(true);
571 }
572
573 /**
574 * Returns the hostname for this address.
575 * If the host is equal to null, then this address refers to any
576 * of the local machine's available network addresses.
577 * this is package private so SocketPermission can make calls into
578 * here without a security check.
579 *
580 * <p>If there is a security manager, this method first
581 * calls its {@code checkConnect} method
582 * with the hostname and {@code -1}
583 * as its arguments to see if the calling code is allowed to know
584 * the hostname for this IP address, i.e., to connect to the host.
585 * If the operation is not allowed, it will return
586 * the textual representation of the IP address.
587 *
588 * @return the host name for this IP address, or if the operation
589 * is not allowed by the security check, the textual
590 * representation of the IP address.
591 *
592 * @param check make security check if true
593 *
594 * @see SecurityManager#checkConnect
595 */
596 String getHostName(boolean check) {
597 if (holder().getHostName() == null) {
598 holder().hostName = InetAddress.getHostFromNameService(this, check);
599 }
600 return holder().getHostName();
601 }
602
603 /**
604 * Gets the fully qualified domain name for this IP address.
605 * Best effort method, meaning we may not be able to return
606 * the FQDN depending on the underlying system configuration.
607 *
608 * <p>If there is a security manager, this method first
609 * calls its {@code checkConnect} method
610 * with the hostname and {@code -1}
611 * as its arguments to see if the calling code is allowed to know
612 * the hostname for this IP address, i.e., to connect to the host.
613 * If the operation is not allowed, it will return
614 * the textual representation of the IP address.
615 *
616 * @return the fully qualified domain name for this IP address,
617 * or if the operation is not allowed by the security check,
618 * the textual representation of the IP address.
619 *
620 * @see SecurityManager#checkConnect
621 *
622 * @since 1.4
623 */
624 public String getCanonicalHostName() {
625 if (canonicalHostName == null) {
626 canonicalHostName =
627 InetAddress.getHostFromNameService(this, true);
628 }
629 return canonicalHostName;
630 }
631
632 /**
633 * Returns the hostname for this address.
634 *
635 * <p>If there is a security manager, this method first
636 * calls its {@code checkConnect} method
637 * with the hostname and {@code -1}
638 * as its arguments to see if the calling code is allowed to know
639 * the hostname for this IP address, i.e., to connect to the host.
640 * If the operation is not allowed, it will return
641 * the textual representation of the IP address.
642 *
643 * @return the host name for this IP address, or if the operation
644 * is not allowed by the security check, the textual
645 * representation of the IP address.
646 *
647 * @param check make security check if true
648 *
649 * @see SecurityManager#checkConnect
650 */
651 private static String getHostFromNameService(InetAddress addr, boolean check) {
652 String host = null;
653 try {
654 // first lookup the hostname
655 host = nameService.getHostByAddr(addr.getAddress());
656
657 /* check to see if calling code is allowed to know
658 * the hostname for this IP address, ie, connect to the host
659 */
660 if (check) {
661 SecurityManager sec = System.getSecurityManager();
662 if (sec != null) {
663 sec.checkConnect(host, -1);
664 }
665 }
666
667 /* now get all the IP addresses for this hostname,
668 * and make sure one of them matches the original IP
669 * address. We do this to try and prevent spoofing.
670 */
671
672 InetAddress[] arr = InetAddress.getAllByName0(host, check);
673 boolean ok = false;
674
675 if(arr != null) {
676 for(int i = 0; !ok && i < arr.length; i++) {
677 ok = addr.equals(arr[i]);
678 }
679 }
680
681 //XXX: if it looks a spoof just return the address?
682 if (!ok) {
683 host = addr.getHostAddress();
684 return host;
685 }
686 } catch (SecurityException e) {
687 host = addr.getHostAddress();
688 } catch (UnknownHostException e) {
689 host = addr.getHostAddress();
690 // let next provider resolve the hostname
691 }
692 return host;
693 }
694
695 /**
696 * Returns the raw IP address of this {@code InetAddress}
697 * object. The result is in network byte order: the highest order
698 * byte of the address is in {@code getAddress()[0]}.
699 *
700 * @return the raw IP address of this object.
701 */
702 public byte[] getAddress() {
703 return null;
704 }
705
706 /**
707 * Returns the IP address string in textual presentation.
708 *
709 * @return the raw IP address in a string format.
710 * @since 1.0.2
711 */
712 public String getHostAddress() {
713 return null;
714 }
715
716 /**
717 * Returns a hashcode for this IP address.
718 *
719 * @return a hash code value for this IP address.
720 */
721 public int hashCode() {
722 return -1;
723 }
724
725 /**
726 * Compares this object against the specified object.
727 * The result is {@code true} if and only if the argument is
728 * not {@code null} and it represents the same IP address as
729 * this object.
730 * <p>
731 * Two instances of {@code InetAddress} represent the same IP
732 * address if the length of the byte arrays returned by
733 * {@code getAddress} is the same for both, and each of the
734 * array components is the same for the byte arrays.
735 *
736 * @param obj the object to compare against.
737 * @return {@code true} if the objects are the same;
738 * {@code false} otherwise.
739 * @see java.net.InetAddress#getAddress()
740 */
741 public boolean equals(Object obj) {
742 return false;
743 }
744
745 /**
746 * Converts this IP address to a {@code String}. The
747 * string returned is of the form: hostname / literal IP
748 * address.
749 *
750 * If the host name is unresolved, no reverse name service lookup
751 * is performed. The hostname part will be represented by an empty string.
752 *
753 * @return a string representation of this IP address.
754 */
755 public String toString() {
756 String hostName = holder().getHostName();
757 return Objects.toString(hostName, "")
758 + "/" + getHostAddress();
759 }
760
761 // mapping from host name to Addresses - either NameServiceAddresses (while
762 // still being looked-up by NameService(s)) or CachedAddresses when cached
763 private static final ConcurrentMap<String, Addresses> cache =
764 new ConcurrentHashMap<>();
765
766 // CachedAddresses that have to expire are kept ordered in this NavigableSet
767 // which is scanned on each access
768 private static final NavigableSet<CachedAddresses> expirySet =
769 new ConcurrentSkipListSet<>();
770
771 // common interface
772 private interface Addresses {
773 InetAddress[] get() throws UnknownHostException;
774 }
775
776 // a holder for cached addresses with required metadata
777 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
778 private static final AtomicLong seq = new AtomicLong();
779 final String host;
780 final InetAddress[] inetAddresses;
781 final long expiryTime; // time of expiry (in terms of System.nanoTime())
782 final long id = seq.incrementAndGet(); // each instance is unique
783
784 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
785 this.host = host;
786 this.inetAddresses = inetAddresses;
787 this.expiryTime = expiryTime;
788 }
789
790 @Override
791 public InetAddress[] get() throws UnknownHostException {
792 if (inetAddresses == null) {
793 throw new UnknownHostException(host);
794 }
795 return inetAddresses;
796 }
797
798 @Override
799 public int compareTo(CachedAddresses other) {
800 // natural order is expiry time -
801 // compare difference of expiry times rather than
802 // expiry times directly, to avoid possible overflow.
803 // (see System.nanoTime() recommendations...)
804 long diff = this.expiryTime - other.expiryTime;
805 if (diff < 0L) return -1;
806 if (diff > 0L) return 1;
807 // ties are broken using unique id
808 return Long.compare(this.id, other.id);
809 }
810 }
811
812 // a name service lookup based Addresses implementation which replaces itself
813 // in cache when the result is obtained
814 private static final class NameServiceAddresses implements Addresses {
815 private final String host;
816 private final InetAddress reqAddr;
817
818 NameServiceAddresses(String host, InetAddress reqAddr) {
819 this.host = host;
820 this.reqAddr = reqAddr;
821 }
822
823 @Override
824 public InetAddress[] get() throws UnknownHostException {
825 Addresses addresses;
826 // only one thread is doing lookup to name service
827 // for particular host at any time.
828 synchronized (this) {
829 // re-check that we are still us + re-install us if slot empty
830 addresses = cache.putIfAbsent(host, this);
831 if (addresses == null) {
832 // this can happen when we were replaced by CachedAddresses in
833 // some other thread, then CachedAddresses expired and were
834 // removed from cache while we were waiting for lock...
835 addresses = this;
836 }
837 // still us ?
838 if (addresses == this) {
839 // lookup name services
840 InetAddress[] inetAddresses;
841 UnknownHostException ex;
842 int cachePolicy;
843 try {
844 inetAddresses = getAddressesFromNameService(host, reqAddr);
845 ex = null;
846 cachePolicy = InetAddressCachePolicy.get();
847 } catch (UnknownHostException uhe) {
848 inetAddresses = null;
849 ex = uhe;
850 cachePolicy = InetAddressCachePolicy.getNegative();
851 }
852 // remove or replace us with cached addresses according to cachePolicy
853 if (cachePolicy == InetAddressCachePolicy.NEVER) {
854 cache.remove(host, this);
855 } else {
856 CachedAddresses cachedAddresses = new CachedAddresses(
857 host,
858 inetAddresses,
859 cachePolicy == InetAddressCachePolicy.FOREVER
860 ? 0L
861 // cachePolicy is in [s] - we need [ns]
862 : System.nanoTime() + 1000_000_000L * cachePolicy
863 );
864 if (cache.replace(host, this, cachedAddresses) &&
865 cachePolicy != InetAddressCachePolicy.FOREVER) {
866 // schedule expiry
867 expirySet.add(cachedAddresses);
868 }
869 }
870 if (inetAddresses == null) {
871 throw ex == null ? new UnknownHostException(host) : ex;
872 }
873 return inetAddresses;
874 }
875 // else addresses != this
876 }
877 // delegate to different addresses when we are already replaced
878 // but outside of synchronized block to avoid any chance of dead-locking
879 return addresses.get();
880 }
881 }
882
883 /**
884 * NameService provides host and address lookup service
885 *
886 * @since 9
887 */
888 private interface NameService {
889
890 /**
891 * Lookup a host mapping by name. Retrieve the IP addresses
892 * associated with a host
893 *
894 * @param host the specified hostname
895 * @return array of IP addresses for the requested host
896 * @throws UnknownHostException
897 * if no IP address for the {@code host} could be found
898 */
899 InetAddress[] lookupAllHostAddr(String host)
900 throws UnknownHostException;
901
902 /**
903 * Lookup the host corresponding to the IP address provided
904 *
905 * @param addr byte array representing an IP address
906 * @return {@code String} representing the host name mapping
907 * @throws UnknownHostException
908 * if no host found for the specified IP address
909 */
910 String getHostByAddr(byte[] addr) throws UnknownHostException;
911
912 }
913
914 /**
915 * The default NameService implementation, which delegates to the underlying
916 * OS network libraries to resolve host address mappings.
917 *
918 * @since 9
919 */
920 private static final class PlatformNameService implements NameService {
921
922 public InetAddress[] lookupAllHostAddr(String host)
923 throws UnknownHostException
924 {
925 return impl.lookupAllHostAddr(host);
926 }
927
928 public String getHostByAddr(byte[] addr)
929 throws UnknownHostException
930 {
931 return impl.getHostByAddr(addr);
932 }
933 }
934
935 /**
936 * The HostsFileNameService provides host address mapping
937 * by reading the entries in a hosts file, which is specified by
938 * {@code jdk.net.hosts.file} system property
939 *
940 * <p>The file format is that which corresponds with the /etc/hosts file
941 * IP Address host alias list.
942 *
943 * <p>When the file lookup is enabled it replaces the default NameService
944 * implementation
945 *
946 * @since 9
947 */
948 private static final class HostsFileNameService implements NameService {
949
950 private final String hostsFile;
951
952 public HostsFileNameService (String hostsFileName) {
953 this.hostsFile = hostsFileName;
954 }
955
956 private String addrToString(byte addr[]) {
957 String stringifiedAddress = null;
958
959 if (addr.length == Inet4Address.INADDRSZ) {
960 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
961 } else { // treat as an IPV6 jobby
962 byte[] newAddr
963 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
964 if (newAddr != null) {
965 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
966 } else {
967 stringifiedAddress = Inet6Address.numericToTextFormat(addr);
968 }
969 }
970 return stringifiedAddress;
971 }
972
973 /**
974 * Lookup the host name corresponding to the IP address provided.
975 * Search the configured host file a host name corresponding to
976 * the specified IP address.
977 *
978 * @param addr byte array representing an IP address
979 * @return {@code String} representing the host name mapping
980 * @throws UnknownHostException
981 * if no host found for the specified IP address
982 */
983 @Override
984 public String getHostByAddr(byte[] addr) throws UnknownHostException {
985 String hostEntry;
986 String host = null;
987
988 String addrString = addrToString(addr);
989 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
990 while (hostsFileScanner.hasNextLine()) {
991 hostEntry = hostsFileScanner.nextLine();
992 if (!hostEntry.startsWith("#")) {
993 hostEntry = removeComments(hostEntry);
994 if (hostEntry.contains(addrString)) {
995 host = extractHost(hostEntry, addrString);
996 if (host != null) {
997 break;
998 }
999 }
1000 }
1001 }
1002 } catch (FileNotFoundException e) {
1003 throw new UnknownHostException("Unable to resolve address "
1004 + addrString + " as hosts file " + hostsFile
1005 + " not found ");
1006 }
1007
1008 if ((host == null) || (host.equals("")) || (host.equals(" "))) {
1009 throw new UnknownHostException("Requested address "
1010 + addrString
1011 + " resolves to an invalid entry in hosts file "
1012 + hostsFile);
1013 }
1014 return host;
1015 }
1016
1017 /**
1018 * <p>Lookup a host mapping by name. Retrieve the IP addresses
1019 * associated with a host.
1020 *
1021 * <p>Search the configured hosts file for the addresses assocaited with
1022 * with the specified host name.
1023 *
1024 * @param host the specified hostname
1025 * @return array of IP addresses for the requested host
1026 * @throws UnknownHostException
1027 * if no IP address for the {@code host} could be found
1028 */
1029 public InetAddress[] lookupAllHostAddr(String host)
1030 throws UnknownHostException {
1031 String hostEntry;
1032 String addrStr = null;
1033 InetAddress[] res = null;
1034 byte addr[] = new byte[4];
1035 ArrayList<InetAddress> inetAddresses = null;
1036
1037 // lookup the file and create a list InetAddress for the specfied host
1038 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
1039 while (hostsFileScanner.hasNextLine()) {
1040 hostEntry = hostsFileScanner.nextLine();
1041 if (!hostEntry.startsWith("#")) {
1042 hostEntry = removeComments(hostEntry);
1043 if (hostEntry.contains(host)) {
1044 addrStr = extractHostAddr(hostEntry, host);
1045 if ((addrStr != null) && (!addrStr.equals(""))) {
1046 addr = createAddressByteArray(addrStr);
1047 if (inetAddresses == null) {
1048 inetAddresses = new ArrayList<>(1);
1049 }
1050 if (addr != null) {
1051 inetAddresses.add(InetAddress.getByAddress(host, addr));
1052 }
1053 }
1054 }
1055 }
1056 }
1057 } catch (FileNotFoundException e) {
1058 throw new UnknownHostException("Unable to resolve host " + host
1059 + " as hosts file " + hostsFile + " not found ");
1060 }
1061
1062 if (inetAddresses != null) {
1063 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]);
1064 } else {
1065 throw new UnknownHostException("Unable to resolve host " + host
1066 + " in hosts file " + hostsFile);
1067 }
1068 return res;
1069 }
1070
1071 private String removeComments(String hostsEntry) {
1072 String filteredEntry = hostsEntry;
1073 int hashIndex;
1074
1075 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1076 filteredEntry = hostsEntry.substring(0, hashIndex);
1077 }
1078 return filteredEntry;
1079 }
1080
1081 private byte [] createAddressByteArray(String addrStr) {
1082 byte[] addrArray;
1083 // check if IPV4 address - most likely
1084 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr);
1085 if (addrArray == null) {
1086 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
1087 }
1088 return addrArray;
1089 }
1090
1091 /** host to ip address mapping */
1092 private String extractHostAddr(String hostEntry, String host) {
1093 String[] mapping = hostEntry.split("\\s+");
1094 String hostAddr = null;
1095
1096 if (mapping.length >= 2) {
1097 // look at the host aliases
1098 for (int i = 1; i < mapping.length; i++) {
1099 if (mapping[i].equalsIgnoreCase(host)) {
1100 hostAddr = mapping[0];
1101 }
1102 }
1103 }
1104 return hostAddr;
1105 }
1106
1107 /**
1108 * IP Address to host mapping
1109 * use first host alias in list
1110 */
1111 private String extractHost(String hostEntry, String addrString) {
1112 String[] mapping = hostEntry.split("\\s+");
1113 String host = null;
1114
1115 if (mapping.length >= 2) {
1116 if (mapping[0].equalsIgnoreCase(addrString)) {
1117 host = mapping[1];
1118 }
1119 }
1120 return host;
1121 }
1122 }
1123
1124 static final InetAddressImpl impl;
1125
1126 static {
1127 // create the impl
1128 impl = InetAddressImplFactory.create();
1129
1130 // create name service
1131 nameService = createNameService();
1132 }
1133
1134 /**
1135 * Create an instance of the NameService interface based on
1136 * the setting of the {@code jdk.net.hosts.file} system property.
1137 *
1138 * <p>The default NameService is the PlatformNameService, which typically
1139 * delegates name and address resolution calls to the underlying
1140 * OS network libraries.
1141 *
1142 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1143 * system property is set. If the specified file doesn't exist, the name or
1144 * address lookup will result in an UnknownHostException. Thus, non existent
1145 * hosts file is handled as if the file is empty.
1146 *
1147 * @return a NameService
1148 */
1149 private static NameService createNameService() {
1150
1151 String hostsFileName =
1152 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file");
1153 NameService theNameService;
1154 if (hostsFileName != null) {
1155 theNameService = new HostsFileNameService(hostsFileName);
1156 } else {
1157 theNameService = new PlatformNameService();
1158 }
1159 return theNameService;
1160 }
1161
1162 /**
1163 * Creates an InetAddress based on the provided host name and IP address.
1164 * No name service is checked for the validity of the address.
1165 *
1166 * <p> The host name can either be a machine name, such as
1167 * "{@code java.sun.com}", or a textual representation of its IP
1168 * address.
1169 * <p> No validity checking is done on the host name either.
1170 *
1171 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1172 * will be returned; otherwise, an instance of Inet6Address
1173 * will be returned.
1174 *
1175 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1176 * must be 16 bytes long
1177 *
1178 * @param host the specified host
1179 * @param addr the raw IP address in network byte order
1180 * @return an InetAddress object created from the raw IP address.
1181 * @exception UnknownHostException if IP address is of illegal length
1182 * @since 1.4
1183 */
1184 public static InetAddress getByAddress(String host, byte[] addr)
1185 throws UnknownHostException {
1186 if (host != null && host.length() > 0 && host.charAt(0) == '[') {
1187 if (host.charAt(host.length()-1) == ']') {
1188 host = host.substring(1, host.length() -1);
1189 }
1190 }
1191 if (addr != null) {
1192 if (addr.length == Inet4Address.INADDRSZ) {
1193 return new Inet4Address(host, addr);
1194 } else if (addr.length == Inet6Address.INADDRSZ) {
1195 byte[] newAddr
1196 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1197 if (newAddr != null) {
1198 return new Inet4Address(host, newAddr);
1199 } else {
1200 return new Inet6Address(host, addr);
1201 }
1202 }
1203 }
1204 throw new UnknownHostException("addr is of illegal length");
1205 }
1206
1207
1208 /**
1209 * Determines the IP address of a host, given the host's name.
1210 *
1211 * <p> The host name can either be a machine name, such as
1212 * "{@code java.sun.com}", or a textual representation of its
1213 * IP address. If a literal IP address is supplied, only the
1214 * validity of the address format is checked.
1215 *
1216 * <p> For {@code host} specified in literal IPv6 address,
1217 * either the form defined in RFC 2732 or the literal IPv6 address
1218 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1219 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1220 * scoped addresses.
1221 *
1222 * <p> If the host is {@code null} then an {@code InetAddress}
1223 * representing an address of the loopback interface is returned.
1224 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1225 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1226 * section 2.5.3. </p>
1227 *
1228 * @param host the specified host, or {@code null}.
1229 * @return an IP address for the given host name.
1230 * @exception UnknownHostException if no IP address for the
1231 * {@code host} could be found, or if a scope_id was specified
1232 * for a global IPv6 address.
1233 * @exception SecurityException if a security manager exists
1234 * and its checkConnect method doesn't allow the operation
1235 */
1236 public static InetAddress getByName(String host)
1237 throws UnknownHostException {
1238 return InetAddress.getAllByName(host)[0];
1239 }
1240
1241 // called from deployment cache manager
1242 private static InetAddress getByName(String host, InetAddress reqAddr)
1243 throws UnknownHostException {
1244 return InetAddress.getAllByName(host, reqAddr)[0];
1245 }
1246
1247 /**
1248 * Given the name of a host, returns an array of its IP addresses,
1249 * based on the configured name service on the system.
1250 *
1251 * <p> The host name can either be a machine name, such as
1252 * "{@code java.sun.com}", or a textual representation of its IP
1253 * address. If a literal IP address is supplied, only the
1254 * validity of the address format is checked.
1255 *
1256 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1257 * either the form defined in RFC 2732 or the literal IPv6 address
1258 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1259 * also be qualified by appending a scoped zone identifier or scope_id.
1260 * The syntax and usage of scope_ids is described
1261 * <a href="Inet6Address.html#scoped">here</a>.
1262 * <p> If the host is {@code null} then an {@code InetAddress}
1263 * representing an address of the loopback interface is returned.
1264 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1265 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1266 * section 2.5.3. </p>
1267 *
1268 * <p> If there is a security manager and {@code host} is not
1269 * null and {@code host.length() } is not equal to zero, the
1270 * security manager's
1271 * {@code checkConnect} method is called
1272 * with the hostname and {@code -1}
1273 * as its arguments to see if the operation is allowed.
1274 *
1275 * @param host the name of the host, or {@code null}.
1276 * @return an array of all the IP addresses for a given host name.
1277 *
1278 * @exception UnknownHostException if no IP address for the
1279 * {@code host} could be found, or if a scope_id was specified
1280 * for a global IPv6 address.
1281 * @exception SecurityException if a security manager exists and its
1282 * {@code checkConnect} method doesn't allow the operation.
1283 *
1284 * @see SecurityManager#checkConnect
1285 */
1286 public static InetAddress[] getAllByName(String host)
1287 throws UnknownHostException {
1288 return getAllByName(host, null);
1289 }
1290
1291 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1292 throws UnknownHostException {
1293
1294 if (host == null || host.length() == 0) {
1295 InetAddress[] ret = new InetAddress[1];
1296 ret[0] = impl.loopbackAddress();
1297 return ret;
1298 }
1299
1300 boolean ipv6Expected = false;
1301 if (host.charAt(0) == '[') {
1302 // This is supposed to be an IPv6 literal
1303 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1304 host = host.substring(1, host.length() -1);
1305 ipv6Expected = true;
1306 } else {
1307 // This was supposed to be a IPv6 address, but it's not!
1308 throw new UnknownHostException(host + ": invalid IPv6 address");
1309 }
1310 }
1311
1312 // if host is an IP address, we won't do further lookup
1313 if (Character.digit(host.charAt(0), 16) != -1
1314 || (host.charAt(0) == ':')) {
1315 byte[] addr = null;
1316 int numericZone = -1;
1317 String ifname = null;
1318 // see if it is IPv4 address
1319 addr = IPAddressUtil.textToNumericFormatV4(host);
1320 if (addr == null) {
1321 // This is supposed to be an IPv6 literal
1322 // Check if a numeric or string zone id is present
1323 int pos;
1324 if ((pos=host.indexOf ('%')) != -1) {
1325 numericZone = checkNumericZone (host);
1326 if (numericZone == -1) { /* remainder of string must be an ifname */
1327 ifname = host.substring (pos+1);
1328 }
1329 }
1330 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1331 throw new UnknownHostException(host + ": invalid IPv6 address");
1332 }
1333 } else if (ipv6Expected) {
1334 // Means an IPv4 litteral between brackets!
1335 throw new UnknownHostException("["+host+"]");
1336 }
1337 InetAddress[] ret = new InetAddress[1];
1338 if(addr != null) {
1339 if (addr.length == Inet4Address.INADDRSZ) {
1340 ret[0] = new Inet4Address(null, addr);
1341 } else {
1342 if (ifname != null) {
1343 ret[0] = new Inet6Address(null, addr, ifname);
1344 } else {
1345 ret[0] = new Inet6Address(null, addr, numericZone);
1346 }
1347 }
1348 return ret;
1349 }
1350 } else if (ipv6Expected) {
1351 // We were expecting an IPv6 Litteral, but got something else
1352 throw new UnknownHostException("["+host+"]");
1353 }
1354 return getAllByName0(host, reqAddr, true, true);
1355 }
1356
1357 /**
1358 * Returns the loopback address.
1359 * <p>
1360 * The InetAddress returned will represent the IPv4
1361 * loopback address, 127.0.0.1, or the IPv6 loopback
1362 * address, ::1. The IPv4 loopback address returned
1363 * is only one of many in the form 127.*.*.*
1364 *
1365 * @return the InetAddress loopback instance.
1366 * @since 1.7
1367 */
1368 public static InetAddress getLoopbackAddress() {
1369 return impl.loopbackAddress();
1370 }
1371
1372
1373 /**
1374 * check if the literal address string has %nn appended
1375 * returns -1 if not, or the numeric value otherwise.
1376 *
1377 * %nn may also be a string that represents the displayName of
1378 * a currently available NetworkInterface.
1379 */
1380 private static int checkNumericZone (String s) throws UnknownHostException {
1381 int percent = s.indexOf ('%');
1382 int slen = s.length();
1383 int digit, zone=0;
1384 if (percent == -1) {
1385 return -1;
1386 }
1387 for (int i=percent+1; i<slen; i++) {
1388 char c = s.charAt(i);
1389 if (c == ']') {
1390 if (i == percent+1) {
1391 /* empty per-cent field */
1392 return -1;
1393 }
1394 break;
1395 }
1396 if ((digit = Character.digit (c, 10)) < 0) {
1397 return -1;
1398 }
1399 zone = (zone * 10) + digit;
1400 }
1401 return zone;
1402 }
1403
1404 private static InetAddress[] getAllByName0 (String host)
1405 throws UnknownHostException
1406 {
1407 return getAllByName0(host, true);
1408 }
1409
1410 /**
1411 * package private so SocketPermission can call it
1412 */
1413 static InetAddress[] getAllByName0 (String host, boolean check)
1414 throws UnknownHostException {
1415 return getAllByName0 (host, null, check, true);
1416 }
1417
1418 /**
1419 * Designated lookup method.
1420 *
1421 * @param host host name to look up
1422 * @param reqAddr requested address to be the 1st in returned array
1423 * @param check perform security check
1424 * @param useCache use cached value if not expired else always
1425 * perform name service lookup (and cache the result)
1426 * @return array of InetAddress(es)
1427 * @throws UnknownHostException if host name is not found
1428 */
1429 private static InetAddress[] getAllByName0(String host,
1430 InetAddress reqAddr,
1431 boolean check,
1432 boolean useCache)
1433 throws UnknownHostException {
1434
1435 /* If it gets here it is presumed to be a hostname */
1436
1437 /* make sure the connection to the host is allowed, before we
1438 * give out a hostname
1439 */
1440 if (check) {
1441 SecurityManager security = System.getSecurityManager();
1442 if (security != null) {
1443 security.checkConnect(host, -1);
1444 }
1445 }
1446
1447 // remove expired addresses from cache - expirySet keeps them ordered
1448 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1449 long now = System.nanoTime();
1450 for (CachedAddresses caddrs : expirySet) {
1451 // compare difference of time instants rather than
1452 // time instants directly, to avoid possible overflow.
1453 // (see System.nanoTime() recommendations...)
1454 if ((caddrs.expiryTime - now) < 0L) {
1455 // ConcurrentSkipListSet uses weakly consistent iterator,
1456 // so removing while iterating is OK...
1457 if (expirySet.remove(caddrs)) {
1458 // ... remove from cache
1459 cache.remove(caddrs.host, caddrs);
1460 }
1461 } else {
1462 // we encountered 1st element that expires in future
1463 break;
1464 }
1465 }
1466
1467 // look-up or remove from cache
1468 Addresses addrs;
1469 if (useCache) {
1470 addrs = cache.get(host);
1471 } else {
1472 addrs = cache.remove(host);
1473 if (addrs != null) {
1474 if (addrs instanceof CachedAddresses) {
1475 // try removing from expirySet too if CachedAddresses
1476 expirySet.remove(addrs);
1477 }
1478 addrs = null;
1479 }
1480 }
1481
1482 if (addrs == null) {
1483 // create a NameServiceAddresses instance which will look up
1484 // the name service and install it within cache...
1485 Addresses oldAddrs = cache.putIfAbsent(
1486 host,
1487 addrs = new NameServiceAddresses(host, reqAddr)
1488 );
1489 if (oldAddrs != null) { // lost putIfAbsent race
1490 addrs = oldAddrs;
1491 }
1492 }
1493
1494 // ask Addresses to get an array of InetAddress(es) and clone it
1495 return addrs.get().clone();
1496 }
1497
1498 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1499 throws UnknownHostException
1500 {
1501 InetAddress[] addresses = null;
1502 UnknownHostException ex = null;
1503
1504 try {
1505 addresses = nameService.lookupAllHostAddr(host);
1506 } catch (UnknownHostException uhe) {
1507 if (host.equalsIgnoreCase("localhost")) {
1508 addresses = new InetAddress[] { impl.loopbackAddress() };
1509 }
1510 else {
1511 ex = uhe;
1512 }
1513 }
1514
1515 if (addresses == null) {
1516 throw ex == null ? new UnknownHostException(host) : ex;
1517 }
1518
1519 // More to do?
1520 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1521 // Find it?
1522 int i = 1;
1523 for (; i < addresses.length; i++) {
1524 if (addresses[i].equals(reqAddr)) {
1525 break;
1526 }
1527 }
1528 // Rotate
1529 if (i < addresses.length) {
1530 InetAddress tmp, tmp2 = reqAddr;
1531 for (int j = 0; j < i; j++) {
1532 tmp = addresses[j];
1533 addresses[j] = tmp2;
1534 tmp2 = tmp;
1535 }
1536 addresses[i] = tmp2;
1537 }
1538 }
1539
1540 return addresses;
1541 }
1542
1543 /**
1544 * Returns an {@code InetAddress} object given the raw IP address .
1545 * The argument is in network byte order: the highest order
1546 * byte of the address is in {@code getAddress()[0]}.
1547 *
1548 * <p> This method doesn't block, i.e. no reverse name service lookup
1549 * is performed.
1550 *
1551 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1552 * must be 16 bytes long
1553 *
1554 * @param addr the raw IP address in network byte order
1555 * @return an InetAddress object created from the raw IP address.
1556 * @exception UnknownHostException if IP address is of illegal length
1557 * @since 1.4
1558 */
1559 public static InetAddress getByAddress(byte[] addr)
1560 throws UnknownHostException {
1561 return getByAddress(null, addr);
1562 }
1563
1564 private static final class CachedLocalHost {
1565 final String host;
1566 final InetAddress addr;
1567 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1568
1569 CachedLocalHost(String host, InetAddress addr) {
1570 this.host = host;
1571 this.addr = addr;
1572 }
1573 }
1574
1575 private static volatile CachedLocalHost cachedLocalHost;
1576
1577 /**
1578 * Returns the address of the local host. This is achieved by retrieving
1579 * the name of the host from the system, then resolving that name into
1580 * an {@code InetAddress}.
1581 *
1582 * <P>Note: The resolved address may be cached for a short period of time.
1583 * </P>
1584 *
1585 * <p>If there is a security manager, its
1586 * {@code checkConnect} method is called
1587 * with the local host name and {@code -1}
1588 * as its arguments to see if the operation is allowed.
1589 * If the operation is not allowed, an InetAddress representing
1590 * the loopback address is returned.
1591 *
1592 * @return the address of the local host.
1593 *
1594 * @exception UnknownHostException if the local host name could not
1595 * be resolved into an address.
1596 *
1597 * @see SecurityManager#checkConnect
1598 * @see java.net.InetAddress#getByName(java.lang.String)
1599 */
1600 public static InetAddress getLocalHost() throws UnknownHostException {
1601
1602 SecurityManager security = System.getSecurityManager();
1603 try {
1604 // is cached data still valid?
1605 CachedLocalHost clh = cachedLocalHost;
1606 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1607 if (security != null) {
1608 security.checkConnect(clh.host, -1);
1609 }
1610 return clh.addr;
1611 }
1612
1613 String local = impl.getLocalHostName();
1614
1615 if (security != null) {
1616 security.checkConnect(local, -1);
1617 }
1618
1619 InetAddress localAddr;
1620 if (local.equals("localhost")) {
1621 // shortcut for "localhost" host name
1622 localAddr = impl.loopbackAddress();
1623 } else {
1624 // call getAllByName0 without security checks and
1625 // without using cached data
1626 try {
1627 localAddr = getAllByName0(local, null, false, false)[0];
1628 } catch (UnknownHostException uhe) {
1629 // Rethrow with a more informative error message.
1630 UnknownHostException uhe2 =
1631 new UnknownHostException(local + ": " +
1632 uhe.getMessage());
1633 uhe2.initCause(uhe);
1634 throw uhe2;
1635 }
1636 }
1637 cachedLocalHost = new CachedLocalHost(local, localAddr);
1638 return localAddr;
1639 } catch (java.lang.SecurityException e) {
1640 return impl.loopbackAddress();
1641 }
1642 }
1643
1644 /**
1645 * Perform class load-time initializations.
1646 */
1647 private static native void init();
1648
1649
1650 /*
1651 * Returns the InetAddress representing anyLocalAddress
1652 * (typically 0.0.0.0 or ::0)
1653 */
1654 static InetAddress anyLocalAddress() {
1655 return impl.anyLocalAddress();
1656 }
1657
1658 /*
1659 * Load and instantiate an underlying impl class
1660 */
1661 static InetAddressImpl loadImpl(String implName) {
1662 Object impl = null;
1663
1664 /*
1665 * Property "impl.prefix" will be prepended to the classname
1666 * of the implementation object we instantiate, to which we
1667 * delegate the real work (like native methods). This
1668 * property can vary across implementations of the java.
1669 * classes. The default is an empty String "".
1670 */
1671 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
1672 try {
1673 @SuppressWarnings("deprecation")
1674 Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
1675 impl = tmp;
1676 } catch (ClassNotFoundException e) {
1677 System.err.println("Class not found: java.net." + prefix +
1678 implName + ":\ncheck impl.prefix property " +
1679 "in your properties file.");
1680 } catch (InstantiationException e) {
1681 System.err.println("Could not instantiate: java.net." + prefix +
1682 implName + ":\ncheck impl.prefix property " +
1683 "in your properties file.");
1684 } catch (IllegalAccessException e) {
1685 System.err.println("Cannot access class: java.net." + prefix +
1686 implName + ":\ncheck impl.prefix property " +
1687 "in your properties file.");
1688 }
1689
1690 if (impl == null) {
1691 try {
1692 @SuppressWarnings("deprecation")
1693 Object tmp = Class.forName(implName).newInstance();
1694 impl = tmp;
1695 } catch (Exception e) {
1696 throw new Error("System property impl.prefix incorrect");
1697 }
1698 }
1699
1700 return (InetAddressImpl) impl;
1701 }
1702
1703 private void readObjectNoData (ObjectInputStream s) throws
1704 IOException, ClassNotFoundException {
1705 if (getClass().getClassLoader() != null) {
1706 throw new SecurityException ("invalid address type");
1707 }
1708 }
1709
1710 private static final jdk.internal.misc.Unsafe UNSAFE
1711 = jdk.internal.misc.Unsafe.getUnsafe();
1712 private static final long FIELDS_OFFSET
1713 = UNSAFE.objectFieldOffset(InetAddress.class, "holder");
1714
1715 private void readObject (ObjectInputStream s) throws
1716 IOException, ClassNotFoundException {
1717 if (getClass().getClassLoader() != null) {
1718 throw new SecurityException ("invalid address type");
1719 }
1720 GetField gf = s.readFields();
1721 String host = (String)gf.get("hostName", null);
1722 int address= gf.get("address", 0);
1723 int family= gf.get("family", 0);
1724 InetAddressHolder h = new InetAddressHolder(host, address, family);
1725 UNSAFE.putObject(this, FIELDS_OFFSET, h);
1726 }
1727
1728 /* needed because the serializable fields no longer exist */
1729
1730 /**
1731 * @serialField hostName String
1732 * @serialField address int
1733 * @serialField family int
1734 */
1735 private static final ObjectStreamField[] serialPersistentFields = {
1736 new ObjectStreamField("hostName", String.class),
1737 new ObjectStreamField("address", int.class),
1738 new ObjectStreamField("family", int.class),
1739 };
1740
1741 private void writeObject (ObjectOutputStream s) throws
1742 IOException {
1743 if (getClass().getClassLoader() != null) {
1744 throw new SecurityException ("invalid address type");
1745 }
1746 PutField pf = s.putFields();
1747 pf.put("hostName", holder().getHostName());
1748 pf.put("address", holder().getAddress());
1749 pf.put("family", holder().getFamily());
1750 s.writeFields();
1751 }
1752 }
1753
1754 /*
1755 * Simple factory to create the impl
1756 */
1757 class InetAddressImplFactory {
1758
1759 static InetAddressImpl create() {
1760 return InetAddress.loadImpl(isIPv6Supported() ?
1761 "Inet6AddressImpl" : "Inet4AddressImpl");
1762 }
1763
1764 static native boolean isIPv6Supported();
1765 }