1 /*
2 * Copyright (c) 1995, 2020, 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.io.File;
33 import java.io.ObjectStreamException;
34 import java.io.ObjectStreamField;
35 import java.io.IOException;
36 import java.io.InvalidObjectException;
37 import java.io.ObjectInputStream;
38 import java.io.ObjectInputStream.GetField;
39 import java.io.ObjectOutputStream;
40 import java.io.ObjectOutputStream.PutField;
41 import java.lang.annotation.Native;
42 import java.util.concurrent.ConcurrentHashMap;
43 import java.util.concurrent.ConcurrentMap;
44 import java.util.concurrent.ConcurrentSkipListSet;
45 import java.util.concurrent.atomic.AtomicLong;
46 import java.util.Arrays;
47
48 import jdk.internal.access.JavaNetInetAddressAccess;
49 import jdk.internal.access.SharedSecrets;
50 import sun.security.action.*;
51 import sun.net.InetAddressCachePolicy;
52 import sun.net.util.IPAddressUtil;
53 import sun.nio.cs.UTF_8;
54
55 /**
56 * This class represents an Internet Protocol (IP) address.
57 *
58 * <p> An IP address is either a 32-bit or 128-bit unsigned number
59 * used by IP, a lower-level protocol on which protocols like UDP and
60 * TCP are built. The IP address architecture is defined by <a
61 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790:
62 * Assigned Numbers</i></a>, <a
63 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918:
64 * Address Allocation for Private Internets</i></a>, <a
65 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365:
66 * Administratively Scoped IP Multicast</i></a>, and <a
67 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP
68 * Version 6 Addressing Architecture</i></a>. An instance of an
69 * InetAddress consists of an IP address and possibly its
70 * corresponding host name (depending on whether it is constructed
71 * with a host name or whether it has already done reverse host name
72 * resolution).
73 *
74 * <h2> Address types </h2>
75 *
76 * <table class="striped" style="margin-left:2em">
77 * <caption style="display:none">Description of unicast and multicast address types</caption>
78 * <thead>
79 * <tr><th scope="col">Address Type</th><th scope="col">Description</th></tr>
80 * </thead>
81 * <tbody>
82 * <tr><th scope="row" style="vertical-align:top">unicast</th>
83 * <td>An identifier for a single interface. A packet sent to
84 * a unicast address is delivered to the interface identified by
85 * that address.
86 *
87 * <p> The Unspecified Address -- Also called anylocal or wildcard
88 * address. It must never be assigned to any node. It indicates the
89 * absence of an address. One example of its use is as the target of
90 * bind, which allows a server to accept a client connection on any
91 * interface, in case the server host has multiple interfaces.
92 *
93 * <p> The <i>unspecified</i> address must not be used as
94 * the destination address of an IP packet.
95 *
96 * <p> The <i>Loopback</i> Addresses -- This is the address
97 * assigned to the loopback interface. Anything sent to this
98 * IP address loops around and becomes IP input on the local
99 * host. This address is often used when testing a
100 * client.</td></tr>
101 * <tr><th scope="row" style="vertical-align:top">multicast</th>
102 * <td>An identifier for a set of interfaces (typically belonging
103 * to different nodes). A packet sent to a multicast address is
104 * delivered to all interfaces identified by that address.</td></tr>
105 * </tbody>
106 * </table>
107 *
108 * <h3> IP address scope </h3>
109 *
110 * <p> <i>Link-local</i> addresses are designed to be used for addressing
111 * on a single link for purposes such as auto-address configuration,
112 * neighbor discovery, or when no routers are present.
113 *
114 * <p> <i>Site-local</i> addresses are designed to be used for addressing
115 * inside of a site without the need for a global prefix.
116 *
117 * <p> <i>Global</i> addresses are unique across the internet.
118 *
119 * <h3> Textual representation of IP addresses </h3>
120 *
121 * The textual representation of an IP address is address family specific.
122 *
123 * <p>
124 *
125 * For IPv4 address format, please refer to <A
126 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6
127 * address format, please refer to <A
128 * HREF="Inet6Address.html#format">Inet6Address#format</A>.
129 *
130 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of
131 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P>
132 *
133 * <h3> Host Name Resolution </h3>
134 *
135 * Host name-to-IP address <i>resolution</i> is accomplished through
136 * the use of a combination of local machine configuration information
137 * and network naming services such as the Domain Name System (DNS)
138 * and Network Information Service(NIS). The particular naming
139 * services(s) being used is by default the local machine configured
140 * one. For any host name, its corresponding IP address is returned.
141 *
142 * <p> <i>Reverse name resolution</i> means that for any IP address,
143 * the host associated with the IP address is returned.
144 *
145 * <p> The InetAddress class provides methods to resolve host names to
146 * their IP addresses and vice versa.
147 *
148 * <h3> InetAddress Caching </h3>
149 *
150 * The InetAddress class has a cache to store successful as well as
151 * unsuccessful host name resolutions.
152 *
153 * <p> By default, when a security manager is installed, in order to
154 * protect against DNS spoofing attacks,
155 * the result of positive host name resolutions are
156 * cached forever. When a security manager is not installed, the default
157 * behavior is to cache entries for a finite (implementation dependent)
158 * period of time. The result of unsuccessful host
159 * name resolution is cached for a very short period of time (10
160 * seconds) to improve performance.
161 *
162 * <p> If the default behavior is not desired, then a Java security property
163 * can be set to a different Time-to-live (TTL) value for positive
164 * caching. Likewise, a system admin can configure a different
165 * negative caching TTL value when needed.
166 *
167 * <p> Two Java security properties control the TTL values used for
168 * positive and negative host name resolution caching:
169 *
170 * <dl style="margin-left:2em">
171 * <dt><b>networkaddress.cache.ttl</b></dt>
172 * <dd>Indicates the caching policy for successful name lookups from
173 * the name service. The value is specified as an integer to indicate
174 * the number of seconds to cache the successful lookup. The default
175 * setting is to cache for an implementation specific period of time.
176 * <p>
177 * A value of -1 indicates "cache forever".
178 * </dd>
179 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt>
180 * <dd>Indicates the caching policy for un-successful name lookups
181 * from the name service. The value is specified as an integer to
182 * indicate the number of seconds to cache the failure for
183 * un-successful lookups.
184 * <p>
185 * A value of 0 indicates "never cache".
186 * A value of -1 indicates "cache forever".
187 * </dd>
188 * </dl>
189 *
190 * @author Chris Warth
191 * @see java.net.InetAddress#getByAddress(byte[])
192 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
193 * @see java.net.InetAddress#getAllByName(java.lang.String)
194 * @see java.net.InetAddress#getByName(java.lang.String)
195 * @see java.net.InetAddress#getLocalHost()
196 * @since 1.0
197 */
198 public 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;
292
293 /**
294 * Used to store the best available hostname.
295 * Lazily initialized via a data race; safe because Strings are immutable.
296 */
297 private transient String canonicalHostName = null;
298
299 /** use serialVersionUID from JDK 1.0.2 for interoperability */
300 @java.io.Serial
301 private static final long serialVersionUID = 3286316764910316507L;
302
303 /*
304 * Load net library into runtime, and perform initializations.
305 */
306 static {
307 String str = GetPropertyAction.privilegedGetProperty("java.net.preferIPv6Addresses");
308 if (str == null) {
309 preferIPv6Address = PREFER_IPV4_VALUE;
310 } else if (str.equalsIgnoreCase("true")) {
311 preferIPv6Address = PREFER_IPV6_VALUE;
312 } else if (str.equalsIgnoreCase("false")) {
313 preferIPv6Address = PREFER_IPV4_VALUE;
314 } else if (str.equalsIgnoreCase("system")) {
315 preferIPv6Address = PREFER_SYSTEM_VALUE;
316 } else {
317 preferIPv6Address = PREFER_IPV4_VALUE;
318 }
319 LoadLibraryAction.privilegedLoadLibrary("net");
320 SharedSecrets.setJavaNetInetAddressAccess(
321 new JavaNetInetAddressAccess() {
322 public String getOriginalHostName(InetAddress ia) {
323 return ia.holder.getOriginalHostName();
324 }
325
326 public InetAddress getByName(String hostName,
327 InetAddress hostAddress)
328 throws UnknownHostException
329 {
330 return InetAddress.getByName(hostName, hostAddress);
331 }
332
333 public int addressValue(Inet4Address inet4Address) {
334 return inet4Address.addressValue();
335 }
336
337 public byte[] addressBytes(Inet6Address inet6Address) {
338 return inet6Address.addressBytes();
339 }
340 }
341 );
342 init();
343 }
344
345 /**
346 * Constructor for the Socket.accept() method.
347 * This creates an empty InetAddress, which is filled in by
348 * the accept() method. This InetAddress, however, is not
349 * put in the address cache, since it is not created by name.
350 */
351 InetAddress() {
352 holder = new InetAddressHolder();
353 }
354
355 /**
356 * Replaces the de-serialized object with an Inet4Address object.
357 *
358 * @return the alternate object to the de-serialized object.
359 *
360 * @throws ObjectStreamException if a new object replacing this
361 * object could not be created
362 */
363 @java.io.Serial
364 private Object readResolve() throws ObjectStreamException {
365 // will replace the deserialized 'this' object
366 return new Inet4Address(holder().getHostName(), holder().getAddress());
367 }
368
369 /**
370 * Utility routine to check if the InetAddress is an
371 * IP multicast address.
372 * @return a {@code boolean} indicating if the InetAddress is
373 * an IP multicast address
374 * @since 1.1
375 */
376 public boolean isMulticastAddress() {
377 return false;
378 }
379
380 /**
381 * Utility routine to check if the InetAddress is a wildcard address.
382 * @return a {@code boolean} indicating if the InetAddress is
383 * a wildcard address.
384 * @since 1.4
385 */
386 public boolean isAnyLocalAddress() {
387 return false;
388 }
389
390 /**
391 * Utility routine to check if the InetAddress is a loopback address.
392 *
393 * @return a {@code boolean} indicating if the InetAddress is
394 * a loopback address; or false otherwise.
395 * @since 1.4
396 */
397 public boolean isLoopbackAddress() {
398 return false;
399 }
400
401 /**
402 * Utility routine to check if the InetAddress is an link local address.
403 *
404 * @return a {@code boolean} indicating if the InetAddress is
405 * a link local address; or false if address is not a link local unicast address.
406 * @since 1.4
407 */
408 public boolean isLinkLocalAddress() {
409 return false;
410 }
411
412 /**
413 * Utility routine to check if the InetAddress is a site local address.
414 *
415 * @return a {@code boolean} indicating if the InetAddress is
416 * a site local address; or false if address is not a site local unicast address.
417 * @since 1.4
418 */
419 public boolean isSiteLocalAddress() {
420 return false;
421 }
422
423 /**
424 * Utility routine to check if the multicast address has global scope.
425 *
426 * @return a {@code boolean} indicating if the address has
427 * is a multicast address of global scope, false if it is not
428 * of global scope or it is not a multicast address
429 * @since 1.4
430 */
431 public boolean isMCGlobal() {
432 return false;
433 }
434
435 /**
436 * Utility routine to check if the multicast address has node scope.
437 *
438 * @return a {@code boolean} indicating if the address has
439 * is a multicast address of node-local scope, false if it is not
440 * of node-local scope or it is not a multicast address
441 * @since 1.4
442 */
443 public boolean isMCNodeLocal() {
444 return false;
445 }
446
447 /**
448 * Utility routine to check if the multicast address has link scope.
449 *
450 * @return a {@code boolean} indicating if the address has
451 * is a multicast address of link-local scope, false if it is not
452 * of link-local scope or it is not a multicast address
453 * @since 1.4
454 */
455 public boolean isMCLinkLocal() {
456 return false;
457 }
458
459 /**
460 * Utility routine to check if the multicast address has site scope.
461 *
462 * @return a {@code boolean} indicating if the address has
463 * is a multicast address of site-local scope, false if it is not
464 * of site-local scope or it is not a multicast address
465 * @since 1.4
466 */
467 public boolean isMCSiteLocal() {
468 return false;
469 }
470
471 /**
472 * Utility routine to check if the multicast address has organization scope.
473 *
474 * @return a {@code boolean} indicating if the address has
475 * is a multicast address of organization-local scope,
476 * false if it is not of organization-local scope
477 * or it is not a multicast address
478 * @since 1.4
479 */
480 public boolean isMCOrgLocal() {
481 return false;
482 }
483
484
485 /**
486 * Test whether that address is reachable. Best effort is made by the
487 * implementation to try to reach the host, but firewalls and server
488 * configuration may block requests resulting in a unreachable status
489 * while some specific ports may be accessible.
490 * A typical implementation will use ICMP ECHO REQUESTs if the
491 * privilege can be obtained, otherwise it will try to establish
492 * a TCP connection on port 7 (Echo) of the destination host.
493 * <p>
494 * The timeout value, in milliseconds, indicates the maximum amount of time
495 * the try should take. If the operation times out before getting an
496 * answer, the host is deemed unreachable. A negative value will result
497 * in an IllegalArgumentException being thrown.
498 *
499 * @param timeout the time, in milliseconds, before the call aborts
500 * @return a {@code boolean} indicating if the address is reachable.
501 * @throws IOException if a network error occurs
502 * @throws IllegalArgumentException if {@code timeout} is negative.
503 * @since 1.5
504 */
505 public boolean isReachable(int timeout) throws IOException {
506 return isReachable(null, 0 , timeout);
507 }
508
509 /**
510 * Test whether that address is reachable. Best effort is made by the
511 * implementation to try to reach the host, but firewalls and server
512 * configuration may block requests resulting in a unreachable status
513 * while some specific ports may be accessible.
514 * A typical implementation will use ICMP ECHO REQUESTs if the
515 * privilege can be obtained, otherwise it will try to establish
516 * a TCP connection on port 7 (Echo) of the destination host.
517 * <p>
518 * The {@code network interface} and {@code ttl} parameters
519 * let the caller specify which network interface the test will go through
520 * and the maximum number of hops the packets should go through.
521 * A negative value for the {@code ttl} will result in an
522 * IllegalArgumentException being thrown.
523 * <p>
524 * The timeout value, in milliseconds, indicates the maximum amount of time
525 * the try should take. If the operation times out before getting an
526 * answer, the host is deemed unreachable. A negative value will result
527 * in an IllegalArgumentException being thrown.
528 *
529 * @param netif the NetworkInterface through which the
530 * test will be done, or null for any interface
531 * @param ttl the maximum numbers of hops to try or 0 for the
532 * default
533 * @param timeout the time, in milliseconds, before the call aborts
534 * @throws IllegalArgumentException if either {@code timeout}
535 * or {@code ttl} are negative.
536 * @return a {@code boolean} indicating if the address is reachable.
537 * @throws IOException if a network error occurs
538 * @since 1.5
539 */
540 public boolean isReachable(NetworkInterface netif, int ttl,
541 int timeout) throws IOException {
542 if (ttl < 0)
543 throw new IllegalArgumentException("ttl can't be negative");
544 if (timeout < 0)
545 throw new IllegalArgumentException("timeout can't be negative");
546
547 return impl.isReachable(this, timeout, netif, ttl);
548 }
549
550 /**
551 * Gets the host name for this IP address.
552 *
553 * <p>If this InetAddress was created with a host name,
554 * this host name will be remembered and returned;
555 * otherwise, a reverse name lookup will be performed
556 * and the result will be returned based on the system
557 * configured name lookup service. If a lookup of the name service
558 * is required, call
559 * {@link #getCanonicalHostName() getCanonicalHostName}.
560 *
561 * <p>If there is a security manager, its
562 * {@code checkConnect} method is first called
563 * with the hostname and {@code -1}
564 * as its arguments to see if the operation is allowed.
565 * If the operation is not allowed, it will return
566 * the textual representation of the IP address.
567 *
568 * @return the host name for this IP address, or if the operation
569 * is not allowed by the security check, the textual
570 * representation of the IP address.
571 *
572 * @see InetAddress#getCanonicalHostName
573 * @see SecurityManager#checkConnect
574 */
575 public String getHostName() {
576 return getHostName(true);
577 }
578
579 /**
580 * Returns the hostname for this address.
581 * If the host is equal to null, then this address refers to any
582 * of the local machine's available network addresses.
583 * this is package private so SocketPermission can make calls into
584 * here without a security check.
585 *
586 * <p>If there is a security manager, this method first
587 * calls its {@code checkConnect} method
588 * with the hostname and {@code -1}
589 * as its arguments to see if the calling code is allowed to know
590 * the hostname for this IP address, i.e., to connect to the host.
591 * If the operation is not allowed, it will return
592 * the textual representation of the IP address.
593 *
594 * @return the host name for this IP address, or if the operation
595 * is not allowed by the security check, the textual
596 * representation of the IP address.
597 *
598 * @param check make security check if true
599 *
600 * @see SecurityManager#checkConnect
601 */
602 String getHostName(boolean check) {
603 if (holder().getHostName() == null) {
604 holder().hostName = InetAddress.getHostFromNameService(this, check);
605 }
606 return holder().getHostName();
607 }
608
609 /**
610 * Gets the fully qualified domain name for this IP address.
611 * Best effort method, meaning we may not be able to return
612 * the FQDN depending on the underlying system configuration.
613 *
614 * <p>If there is a security manager, this method first
615 * calls its {@code checkConnect} method
616 * with the hostname and {@code -1}
617 * as its arguments to see if the calling code is allowed to know
618 * the hostname for this IP address, i.e., to connect to the host.
619 * If the operation is not allowed, it will return
620 * the textual representation of the IP address.
621 *
622 * @return the fully qualified domain name for this IP address,
623 * or if the operation is not allowed by the security check,
624 * the textual representation of the IP address.
625 *
626 * @see SecurityManager#checkConnect
627 *
628 * @since 1.4
629 */
630 public String getCanonicalHostName() {
631 String value = canonicalHostName;
632 if (value == null)
633 canonicalHostName = value =
634 InetAddress.getHostFromNameService(this, true);
635 return value;
636 }
637
638 /**
639 * Returns the hostname for this address.
640 *
641 * <p>If there is a security manager, this method first
642 * calls its {@code checkConnect} method
643 * with the hostname and {@code -1}
644 * as its arguments to see if the calling code is allowed to know
645 * the hostname for this IP address, i.e., to connect to the host.
646 * If the operation is not allowed, it will return
647 * the textual representation of the IP address.
648 *
649 * @return the host name for this IP address, or if the operation
650 * is not allowed by the security check, the textual
651 * representation of the IP address.
652 *
653 * @param check make security check if true
654 *
655 * @see SecurityManager#checkConnect
656 */
657 private static String getHostFromNameService(InetAddress addr, boolean check) {
658 String host = null;
659 try {
660 // first lookup the hostname
661 host = nameService.getHostByAddr(addr.getAddress());
662
663 /* check to see if calling code is allowed to know
664 * the hostname for this IP address, ie, connect to the host
665 */
666 if (check) {
667 SecurityManager sec = System.getSecurityManager();
668 if (sec != null) {
669 sec.checkConnect(host, -1);
670 }
671 }
672
673 /* now get all the IP addresses for this hostname,
674 * and make sure one of them matches the original IP
675 * address. We do this to try and prevent spoofing.
676 */
677
678 InetAddress[] arr = InetAddress.getAllByName0(host, check);
679 boolean ok = false;
680
681 if(arr != null) {
682 for(int i = 0; !ok && i < arr.length; i++) {
683 ok = addr.equals(arr[i]);
684 }
685 }
686
687 //XXX: if it looks a spoof just return the address?
688 if (!ok) {
689 host = addr.getHostAddress();
690 return host;
691 }
692 } catch (SecurityException e) {
693 host = addr.getHostAddress();
694 } catch (UnknownHostException e) {
695 host = addr.getHostAddress();
696 // let next provider resolve the hostname
697 }
698 return host;
699 }
700
701 /**
702 * Returns the raw IP address of this {@code InetAddress}
703 * object. The result is in network byte order: the highest order
704 * byte of the address is in {@code getAddress()[0]}.
705 *
706 * @return the raw IP address of this object.
707 */
708 public byte[] getAddress() {
709 return null;
710 }
711
712 /**
713 * Returns the IP address string in textual presentation.
714 *
715 * @return the raw IP address in a string format.
716 * @since 1.0.2
717 */
718 public String getHostAddress() {
719 return null;
720 }
721
722 /**
723 * Returns a hashcode for this IP address.
724 *
725 * @return a hash code value for this IP address.
726 */
727 public int hashCode() {
728 return -1;
729 }
730
731 /**
732 * Compares this object against the specified object.
733 * The result is {@code true} if and only if the argument is
734 * not {@code null} and it represents the same IP address as
735 * this object.
736 * <p>
737 * Two instances of {@code InetAddress} represent the same IP
738 * address if the length of the byte arrays returned by
739 * {@code getAddress} is the same for both, and each of the
740 * array components is the same for the byte arrays.
741 *
742 * @param obj the object to compare against.
743 * @return {@code true} if the objects are the same;
744 * {@code false} otherwise.
745 * @see java.net.InetAddress#getAddress()
746 */
747 public boolean equals(Object obj) {
748 return false;
749 }
750
751 /**
752 * Converts this IP address to a {@code String}. The
753 * string returned is of the form: hostname / literal IP
754 * address.
755 *
756 * If the host name is unresolved, no reverse name service lookup
757 * is performed. The hostname part will be represented by an empty string.
758 *
759 * @return a string representation of this IP address.
760 */
761 public String toString() {
762 String hostName = holder().getHostName();
763 return Objects.toString(hostName, "")
764 + "/" + getHostAddress();
765 }
766
767 // mapping from host name to Addresses - either NameServiceAddresses (while
768 // still being looked-up by NameService(s)) or CachedAddresses when cached
769 private static final ConcurrentMap<String, Addresses> cache =
770 new ConcurrentHashMap<>();
771
772 // CachedAddresses that have to expire are kept ordered in this NavigableSet
773 // which is scanned on each access
774 private static final NavigableSet<CachedAddresses> expirySet =
775 new ConcurrentSkipListSet<>();
776
777 // common interface
778 private interface Addresses {
779 InetAddress[] get() throws UnknownHostException;
780 }
781
782 // a holder for cached addresses with required metadata
783 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
784 private static final AtomicLong seq = new AtomicLong();
785 final String host;
786 final InetAddress[] inetAddresses;
787 final long expiryTime; // time of expiry (in terms of System.nanoTime())
788 final long id = seq.incrementAndGet(); // each instance is unique
789
790 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
791 this.host = host;
792 this.inetAddresses = inetAddresses;
793 this.expiryTime = expiryTime;
794 }
795
796 @Override
797 public InetAddress[] get() throws UnknownHostException {
798 if (inetAddresses == null) {
799 throw new UnknownHostException(host);
800 }
801 return inetAddresses;
802 }
803
804 @Override
805 public int compareTo(CachedAddresses other) {
806 // natural order is expiry time -
807 // compare difference of expiry times rather than
808 // expiry times directly, to avoid possible overflow.
809 // (see System.nanoTime() recommendations...)
810 long diff = this.expiryTime - other.expiryTime;
811 if (diff < 0L) return -1;
812 if (diff > 0L) return 1;
813 // ties are broken using unique id
814 return Long.compare(this.id, other.id);
815 }
816 }
817
818 // a name service lookup based Addresses implementation which replaces itself
819 // in cache when the result is obtained
820 private static final class NameServiceAddresses implements Addresses {
821 private final String host;
822 private final InetAddress reqAddr;
823
824 NameServiceAddresses(String host, InetAddress reqAddr) {
825 this.host = host;
826 this.reqAddr = reqAddr;
827 }
828
829 @Override
830 public InetAddress[] get() throws UnknownHostException {
831 Addresses addresses;
832 // only one thread is doing lookup to name service
833 // for particular host at any time.
834 synchronized (this) {
835 // re-check that we are still us + re-install us if slot empty
836 addresses = cache.putIfAbsent(host, this);
837 if (addresses == null) {
838 // this can happen when we were replaced by CachedAddresses in
839 // some other thread, then CachedAddresses expired and were
840 // removed from cache while we were waiting for lock...
841 addresses = this;
842 }
843 // still us ?
844 if (addresses == this) {
845 // lookup name services
846 InetAddress[] inetAddresses;
847 UnknownHostException ex;
848 int cachePolicy;
849 try {
850 inetAddresses = getAddressesFromNameService(host, reqAddr);
851 ex = null;
852 cachePolicy = InetAddressCachePolicy.get();
853 } catch (UnknownHostException uhe) {
854 inetAddresses = null;
855 ex = uhe;
856 cachePolicy = InetAddressCachePolicy.getNegative();
857 }
858 // remove or replace us with cached addresses according to cachePolicy
859 if (cachePolicy == InetAddressCachePolicy.NEVER) {
860 cache.remove(host, this);
861 } else {
862 CachedAddresses cachedAddresses = new CachedAddresses(
863 host,
864 inetAddresses,
865 cachePolicy == InetAddressCachePolicy.FOREVER
866 ? 0L
867 // cachePolicy is in [s] - we need [ns]
868 : System.nanoTime() + 1000_000_000L * cachePolicy
869 );
870 if (cache.replace(host, this, cachedAddresses) &&
871 cachePolicy != InetAddressCachePolicy.FOREVER) {
872 // schedule expiry
873 expirySet.add(cachedAddresses);
874 }
875 }
876 if (inetAddresses == null) {
877 throw ex == null ? new UnknownHostException(host) : ex;
878 }
879 return inetAddresses;
880 }
881 // else addresses != this
882 }
883 // delegate to different addresses when we are already replaced
884 // but outside of synchronized block to avoid any chance of dead-locking
885 return addresses.get();
886 }
887 }
888
889 /**
890 * NameService provides host and address lookup service
891 *
892 * @since 9
893 */
894 private interface NameService {
895
896 /**
897 * Lookup a host mapping by name. Retrieve the IP addresses
898 * associated with a host
899 *
900 * @param host the specified hostname
901 * @return array of IP addresses for the requested host
902 * @throws UnknownHostException
903 * if no IP address for the {@code host} could be found
904 */
905 InetAddress[] lookupAllHostAddr(String host)
906 throws UnknownHostException;
907
908 /**
909 * Lookup the host corresponding to the IP address provided
910 *
911 * @param addr byte array representing an IP address
912 * @return {@code String} representing the host name mapping
913 * @throws UnknownHostException
914 * if no host found for the specified IP address
915 */
916 String getHostByAddr(byte[] addr) throws UnknownHostException;
917
918 }
919
920 /**
921 * The default NameService implementation, which delegates to the underlying
922 * OS network libraries to resolve host address mappings.
923 *
924 * @since 9
925 */
926 private static final class PlatformNameService implements NameService {
927
928 public InetAddress[] lookupAllHostAddr(String host)
929 throws UnknownHostException
930 {
931 return impl.lookupAllHostAddr(host);
932 }
933
934 public String getHostByAddr(byte[] addr)
935 throws UnknownHostException
936 {
937 return impl.getHostByAddr(addr);
938 }
939 }
940
941 /**
942 * The HostsFileNameService provides host address mapping
943 * by reading the entries in a hosts file, which is specified by
944 * {@code jdk.net.hosts.file} system property
945 *
946 * <p>The file format is that which corresponds with the /etc/hosts file
947 * IP Address host alias list.
948 *
949 * <p>When the file lookup is enabled it replaces the default NameService
950 * implementation
951 *
952 * @since 9
953 */
954 private static final class HostsFileNameService implements NameService {
955
956 private final String hostsFile;
957
958 public HostsFileNameService (String hostsFileName) {
959 this.hostsFile = hostsFileName;
960 }
961
962 private String addrToString(byte addr[]) {
963 String stringifiedAddress = null;
964
965 if (addr.length == Inet4Address.INADDRSZ) {
966 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
967 } else { // treat as an IPV6 jobby
968 byte[] newAddr
969 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
970 if (newAddr != null) {
971 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
972 } else {
973 stringifiedAddress = Inet6Address.numericToTextFormat(addr);
974 }
975 }
976 return stringifiedAddress;
977 }
978
979 /**
980 * Lookup the host name corresponding to the IP address provided.
981 * Search the configured host file a host name corresponding to
982 * the specified IP address.
983 *
984 * @param addr byte array representing an IP address
985 * @return {@code String} representing the host name mapping
986 * @throws UnknownHostException
987 * if no host found for the specified IP address
988 */
989 @Override
990 public String getHostByAddr(byte[] addr) throws UnknownHostException {
991 String hostEntry;
992 String host = null;
993
994 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
995 UTF_8.INSTANCE))
996 {
997 while (hostsFileScanner.hasNextLine()) {
998 hostEntry = hostsFileScanner.nextLine();
999 if (!hostEntry.startsWith("#")) {
1000 hostEntry = removeComments(hostEntry);
1001 String[] mapping = hostEntry.split("\\s+");
1002 if (mapping.length >= 2 &&
1003 Arrays.equals(addr, createAddressByteArray(mapping[0]))) {
1004 host = mapping[1];
1005 break;
1006 }
1007 }
1008 }
1009 } catch (IOException e) {
1010 throw new UnknownHostException("Unable to resolve address "
1011 + Arrays.toString(addr) + " as hosts file " + hostsFile
1012 + " not found ");
1013 }
1014
1015 if ((host == null) || (host.isEmpty()) || (host.equals(" "))) {
1016 throw new UnknownHostException("Requested address "
1017 + Arrays.toString(addr)
1018 + " resolves to an invalid entry in hosts file "
1019 + hostsFile);
1020 }
1021 return host;
1022 }
1023
1024 /**
1025 * <p>Lookup a host mapping by name. Retrieve the IP addresses
1026 * associated with a host.
1027 *
1028 * <p>Search the configured hosts file for the addresses associated
1029 * with the specified host name.
1030 *
1031 * @param host the specified hostname
1032 * @return array of IP addresses for the requested host
1033 * @throws UnknownHostException
1034 * if no IP address for the {@code host} could be found
1035 */
1036 public InetAddress[] lookupAllHostAddr(String host)
1037 throws UnknownHostException {
1038 String hostEntry;
1039 String addrStr = null;
1040 InetAddress[] res = null;
1041 byte addr[] = new byte[4];
1042 ArrayList<InetAddress> inetAddresses = null;
1043
1044 // lookup the file and create a list InetAddress for the specified host
1045 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
1046 UTF_8.INSTANCE))
1047 {
1048 while (hostsFileScanner.hasNextLine()) {
1049 hostEntry = hostsFileScanner.nextLine();
1050 if (!hostEntry.startsWith("#")) {
1051 hostEntry = removeComments(hostEntry);
1052 if (hostEntry.contains(host)) {
1053 addrStr = extractHostAddr(hostEntry, host);
1054 if ((addrStr != null) && (!addrStr.isEmpty())) {
1055 addr = createAddressByteArray(addrStr);
1056 if (inetAddresses == null) {
1057 inetAddresses = new ArrayList<>(1);
1058 }
1059 if (addr != null) {
1060 inetAddresses.add(InetAddress.getByAddress(host, addr));
1061 }
1062 }
1063 }
1064 }
1065 }
1066 } catch (IOException e) {
1067 throw new UnknownHostException("Unable to resolve host " + host
1068 + " as hosts file " + hostsFile + " not found ");
1069 }
1070
1071 if (inetAddresses != null) {
1072 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]);
1073 } else {
1074 throw new UnknownHostException("Unable to resolve host " + host
1075 + " in hosts file " + hostsFile);
1076 }
1077 return res;
1078 }
1079
1080 private String removeComments(String hostsEntry) {
1081 String filteredEntry = hostsEntry;
1082 int hashIndex;
1083
1084 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1085 filteredEntry = hostsEntry.substring(0, hashIndex);
1086 }
1087 return filteredEntry;
1088 }
1089
1090 private byte [] createAddressByteArray(String addrStr) {
1091 byte[] addrArray;
1092 // check if IPV4 address - most likely
1093 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr);
1094 if (addrArray == null) {
1095 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
1096 }
1097 return addrArray;
1098 }
1099
1100 /** host to ip address mapping */
1101 private String extractHostAddr(String hostEntry, String host) {
1102 String[] mapping = hostEntry.split("\\s+");
1103 String hostAddr = null;
1104
1105 if (mapping.length >= 2) {
1106 // look at the host aliases
1107 for (int i = 1; i < mapping.length; i++) {
1108 if (mapping[i].equalsIgnoreCase(host)) {
1109 hostAddr = mapping[0];
1110 }
1111 }
1112 }
1113 return hostAddr;
1114 }
1115 }
1116
1117 static final InetAddressImpl impl;
1118
1119 static {
1120 // create the impl
1121 impl = InetAddressImplFactory.create();
1122
1123 // create name service
1124 nameService = createNameService();
1125 }
1126
1127 /**
1128 * Create an instance of the NameService interface based on
1129 * the setting of the {@code jdk.net.hosts.file} system property.
1130 *
1131 * <p>The default NameService is the PlatformNameService, which typically
1132 * delegates name and address resolution calls to the underlying
1133 * OS network libraries.
1134 *
1135 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1136 * system property is set. If the specified file doesn't exist, the name or
1137 * address lookup will result in an UnknownHostException. Thus, non existent
1138 * hosts file is handled as if the file is empty.
1139 *
1140 * @return a NameService
1141 */
1142 private static NameService createNameService() {
1143
1144 String hostsFileName =
1145 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file");
1146 NameService theNameService;
1147 if (hostsFileName != null) {
1148 theNameService = new HostsFileNameService(hostsFileName);
1149 } else {
1150 theNameService = new PlatformNameService();
1151 }
1152 return theNameService;
1153 }
1154
1155 /**
1156 * Creates an InetAddress based on the provided host name and IP address.
1157 * No name service is checked for the validity of the address.
1158 *
1159 * <p> The host name can either be a machine name, such as
1160 * "{@code www.example.com}", or a textual representation of its IP
1161 * address.
1162 * <p> No validity checking is done on the host name either.
1163 *
1164 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1165 * will be returned; otherwise, an instance of Inet6Address
1166 * will be returned.
1167 *
1168 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1169 * must be 16 bytes long
1170 *
1171 * @param host the specified host
1172 * @param addr the raw IP address in network byte order
1173 * @return an InetAddress object created from the raw IP address.
1174 * @throws UnknownHostException if IP address is of illegal length
1175 * @since 1.4
1176 */
1177 public static InetAddress getByAddress(String host, byte[] addr)
1178 throws UnknownHostException {
1179 if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
1180 if (host.charAt(host.length()-1) == ']') {
1181 host = host.substring(1, host.length() -1);
1182 }
1183 }
1184 if (addr != null) {
1185 if (addr.length == Inet4Address.INADDRSZ) {
1186 return new Inet4Address(host, addr);
1187 } else if (addr.length == Inet6Address.INADDRSZ) {
1188 byte[] newAddr
1189 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1190 if (newAddr != null) {
1191 return new Inet4Address(host, newAddr);
1192 } else {
1193 return new Inet6Address(host, addr);
1194 }
1195 }
1196 }
1197 throw new UnknownHostException("addr is of illegal length");
1198 }
1199
1200
1201 /**
1202 * Determines the IP address of a host, given the host's name.
1203 *
1204 * <p> The host name can either be a machine name, such as
1205 * "{@code www.example.com}", or a textual representation of its
1206 * IP address. If a literal IP address is supplied, only the
1207 * validity of the address format is checked.
1208 *
1209 * <p> For {@code host} specified in literal IPv6 address,
1210 * either the form defined in RFC 2732 or the literal IPv6 address
1211 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1212 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1213 * scoped addresses.
1214 *
1215 * <p> If the host is {@code null} or {@code host.length()} is equal
1216 * to zero, then an {@code InetAddress} representing an address of the
1217 * loopback interface is returned.
1218 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1219 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1220 * section 2.5.3.
1221 *
1222 * <p> If there is a security manager, and {@code host} is not {@code null}
1223 * or {@code host.length() } is not equal to zero, the security manager's
1224 * {@code checkConnect} method is called with the hostname and {@code -1}
1225 * as its arguments to determine if the operation is allowed.
1226 *
1227 * @param host the specified host, or {@code null}.
1228 * @return an IP address for the given host name.
1229 * @throws UnknownHostException if no IP address for the
1230 * {@code host} could be found, or if a scope_id was specified
1231 * for a global IPv6 address.
1232 * @throws SecurityException if a security manager exists
1233 * and its checkConnect method doesn't allow the operation
1234 */
1235 public static InetAddress getByName(String host)
1236 throws UnknownHostException {
1237 return InetAddress.getAllByName(host)[0];
1238 }
1239
1240 // called from deployment cache manager
1241 private static InetAddress getByName(String host, InetAddress reqAddr)
1242 throws UnknownHostException {
1243 return InetAddress.getAllByName(host, reqAddr)[0];
1244 }
1245
1246 /**
1247 * Given the name of a host, returns an array of its IP addresses,
1248 * based on the configured name service on the system.
1249 *
1250 * <p> The host name can either be a machine name, such as
1251 * "{@code www.example.com}", or a textual representation of its IP
1252 * address. If a literal IP address is supplied, only the
1253 * validity of the address format is checked.
1254 *
1255 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1256 * either the form defined in RFC 2732 or the literal IPv6 address
1257 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1258 * also be qualified by appending a scoped zone identifier or scope_id.
1259 * The syntax and usage of scope_ids is described
1260 * <a href="Inet6Address.html#scoped">here</a>.
1261 *
1262 * <p> If the host is {@code null} or {@code host.length()} is equal
1263 * to zero, then an {@code InetAddress} representing an address of the
1264 * loopback interface is returned.
1265 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1266 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1267 * section 2.5.3. </p>
1268 *
1269 * <p> If there is a security manager, and {@code host} is not {@code null}
1270 * or {@code host.length() } is not equal to zero, the security manager's
1271 * {@code checkConnect} method is called with the hostname and {@code -1}
1272 * as its arguments to determine if the operation is allowed.
1273 *
1274 * @param host the name of the host, or {@code null}.
1275 * @return an array of all the IP addresses for a given host name.
1276 *
1277 * @throws UnknownHostException if no IP address for the
1278 * {@code host} could be found, or if a scope_id was specified
1279 * for a global IPv6 address.
1280 * @throws SecurityException if a security manager exists and its
1281 * {@code checkConnect} method doesn't allow the operation.
1282 *
1283 * @see SecurityManager#checkConnect
1284 */
1285 public static InetAddress[] getAllByName(String host)
1286 throws UnknownHostException {
1287 return getAllByName(host, null);
1288 }
1289
1290 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1291 throws UnknownHostException {
1292
1293 if (host == null || host.isEmpty()) {
1294 InetAddress[] ret = new InetAddress[1];
1295 ret[0] = impl.loopbackAddress();
1296 return ret;
1297 }
1298
1299 boolean ipv6Expected = false;
1300 if (host.charAt(0) == '[') {
1301 // This is supposed to be an IPv6 literal
1302 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1303 host = host.substring(1, host.length() -1);
1304 ipv6Expected = true;
1305 } else {
1306 // This was supposed to be a IPv6 address, but it's not!
1307 throw new UnknownHostException(host + ": invalid IPv6 address");
1308 }
1309 }
1310
1311 // if host is an IP address, we won't do further lookup
1312 if (Character.digit(host.charAt(0), 16) != -1
1313 || (host.charAt(0) == ':')) {
1314 byte[] addr = null;
1315 int numericZone = -1;
1316 String ifname = null;
1317 // see if it is IPv4 address
1318 addr = IPAddressUtil.textToNumericFormatV4(host);
1319 if (addr == null) {
1320 // This is supposed to be an IPv6 literal
1321 // Check if a numeric or string zone id is present
1322 int pos;
1323 if ((pos=host.indexOf ('%')) != -1) {
1324 numericZone = checkNumericZone (host);
1325 if (numericZone == -1) { /* remainder of string must be an ifname */
1326 ifname = host.substring (pos+1);
1327 }
1328 }
1329 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1330 throw new UnknownHostException(host + ": invalid IPv6 address");
1331 }
1332 } else if (ipv6Expected) {
1333 // Means an IPv4 literal between brackets!
1334 throw new UnknownHostException("["+host+"]");
1335 }
1336 InetAddress[] ret = new InetAddress[1];
1337 if(addr != null) {
1338 if (addr.length == Inet4Address.INADDRSZ) {
1339 ret[0] = new Inet4Address(null, addr);
1340 } else {
1341 if (ifname != null) {
1342 ret[0] = new Inet6Address(null, addr, ifname);
1343 } else {
1344 ret[0] = new Inet6Address(null, addr, numericZone);
1345 }
1346 }
1347 return ret;
1348 }
1349 } else if (ipv6Expected) {
1350 // We were expecting an IPv6 Literal, but got something else
1351 throw new UnknownHostException("["+host+"]");
1352 }
1353 return getAllByName0(host, reqAddr, true, true);
1354 }
1355
1356 /**
1357 * Returns the loopback address.
1358 * <p>
1359 * The InetAddress returned will represent the IPv4
1360 * loopback address, 127.0.0.1, or the IPv6 loopback
1361 * address, ::1. The IPv4 loopback address returned
1362 * is only one of many in the form 127.*.*.*
1363 *
1364 * @return the InetAddress loopback instance.
1365 * @since 1.7
1366 */
1367 public static InetAddress getLoopbackAddress() {
1368 return impl.loopbackAddress();
1369 }
1370
1371
1372 /**
1373 * check if the literal address string has %nn appended
1374 * returns -1 if not, or the numeric value otherwise.
1375 *
1376 * %nn may also be a string that represents the displayName of
1377 * a currently available NetworkInterface.
1378 */
1379 private static int checkNumericZone (String s) throws UnknownHostException {
1380 int percent = s.indexOf ('%');
1381 int slen = s.length();
1382 int digit, zone=0;
1383 if (percent == -1) {
1384 return -1;
1385 }
1386 for (int i=percent+1; i<slen; i++) {
1387 char c = s.charAt(i);
1388 if (c == ']') {
1389 if (i == percent+1) {
1390 /* empty per-cent field */
1391 return -1;
1392 }
1393 break;
1394 }
1395 if ((digit = Character.digit (c, 10)) < 0) {
1396 return -1;
1397 }
1398 zone = (zone * 10) + digit;
1399 }
1400 return zone;
1401 }
1402
1403 private static InetAddress[] getAllByName0 (String host)
1404 throws UnknownHostException
1405 {
1406 return getAllByName0(host, true);
1407 }
1408
1409 /**
1410 * package private so SocketPermission can call it
1411 */
1412 static InetAddress[] getAllByName0 (String host, boolean check)
1413 throws UnknownHostException {
1414 return getAllByName0 (host, null, check, true);
1415 }
1416
1417 /**
1418 * Designated lookup method.
1419 *
1420 * @param host host name to look up
1421 * @param reqAddr requested address to be the 1st in returned array
1422 * @param check perform security check
1423 * @param useCache use cached value if not expired else always
1424 * perform name service lookup (and cache the result)
1425 * @return array of InetAddress(es)
1426 * @throws UnknownHostException if host name is not found
1427 */
1428 private static InetAddress[] getAllByName0(String host,
1429 InetAddress reqAddr,
1430 boolean check,
1431 boolean useCache)
1432 throws UnknownHostException {
1433
1434 /* If it gets here it is presumed to be a hostname */
1435
1436 /* make sure the connection to the host is allowed, before we
1437 * give out a hostname
1438 */
1439 if (check) {
1440 SecurityManager security = System.getSecurityManager();
1441 if (security != null) {
1442 security.checkConnect(host, -1);
1443 }
1444 }
1445
1446 // remove expired addresses from cache - expirySet keeps them ordered
1447 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1448 long now = System.nanoTime();
1449 for (CachedAddresses caddrs : expirySet) {
1450 // compare difference of time instants rather than
1451 // time instants directly, to avoid possible overflow.
1452 // (see System.nanoTime() recommendations...)
1453 if ((caddrs.expiryTime - now) < 0L) {
1454 // ConcurrentSkipListSet uses weakly consistent iterator,
1455 // so removing while iterating is OK...
1456 if (expirySet.remove(caddrs)) {
1457 // ... remove from cache
1458 cache.remove(caddrs.host, caddrs);
1459 }
1460 } else {
1461 // we encountered 1st element that expires in future
1462 break;
1463 }
1464 }
1465
1466 // look-up or remove from cache
1467 Addresses addrs;
1468 if (useCache) {
1469 addrs = cache.get(host);
1470 } else {
1471 addrs = cache.remove(host);
1472 if (addrs != null) {
1473 if (addrs instanceof CachedAddresses) {
1474 // try removing from expirySet too if CachedAddresses
1475 expirySet.remove(addrs);
1476 }
1477 addrs = null;
1478 }
1479 }
1480
1481 if (addrs == null) {
1482 // create a NameServiceAddresses instance which will look up
1483 // the name service and install it within cache...
1484 Addresses oldAddrs = cache.putIfAbsent(
1485 host,
1486 addrs = new NameServiceAddresses(host, reqAddr)
1487 );
1488 if (oldAddrs != null) { // lost putIfAbsent race
1489 addrs = oldAddrs;
1490 }
1491 }
1492
1493 // ask Addresses to get an array of InetAddress(es) and clone it
1494 return addrs.get().clone();
1495 }
1496
1497 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1498 throws UnknownHostException
1499 {
1500 InetAddress[] addresses = null;
1501 UnknownHostException ex = null;
1502
1503 try {
1504 addresses = nameService.lookupAllHostAddr(host);
1505 } catch (UnknownHostException uhe) {
1506 if (host.equalsIgnoreCase("localhost")) {
1507 addresses = new InetAddress[] { impl.loopbackAddress() };
1508 }
1509 else {
1510 ex = uhe;
1511 }
1512 }
1513
1514 if (addresses == null) {
1515 throw ex == null ? new UnknownHostException(host) : ex;
1516 }
1517
1518 // More to do?
1519 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1520 // Find it?
1521 int i = 1;
1522 for (; i < addresses.length; i++) {
1523 if (addresses[i].equals(reqAddr)) {
1524 break;
1525 }
1526 }
1527 // Rotate
1528 if (i < addresses.length) {
1529 InetAddress tmp, tmp2 = reqAddr;
1530 for (int j = 0; j < i; j++) {
1531 tmp = addresses[j];
1532 addresses[j] = tmp2;
1533 tmp2 = tmp;
1534 }
1535 addresses[i] = tmp2;
1536 }
1537 }
1538
1539 return addresses;
1540 }
1541
1542 /**
1543 * Returns an {@code InetAddress} object given the raw IP address .
1544 * The argument is in network byte order: the highest order
1545 * byte of the address is in {@code getAddress()[0]}.
1546 *
1547 * <p> This method doesn't block, i.e. no reverse name service lookup
1548 * is performed.
1549 *
1550 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1551 * must be 16 bytes long
1552 *
1553 * @param addr the raw IP address in network byte order
1554 * @return an InetAddress object created from the raw IP address.
1555 * @throws UnknownHostException if IP address is of illegal length
1556 * @since 1.4
1557 */
1558 public static InetAddress getByAddress(byte[] addr)
1559 throws UnknownHostException {
1560 return getByAddress(null, addr);
1561 }
1562
1563 private static final class CachedLocalHost {
1564 final String host;
1565 final InetAddress addr;
1566 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1567
1568 CachedLocalHost(String host, InetAddress addr) {
1569 this.host = host;
1570 this.addr = addr;
1571 }
1572 }
1573
1574 private static volatile CachedLocalHost cachedLocalHost;
1575
1576 /**
1577 * Returns the address of the local host. This is achieved by retrieving
1578 * the name of the host from the system, then resolving that name into
1579 * an {@code InetAddress}.
1580 *
1581 * <P>Note: The resolved address may be cached for a short period of time.
1582 * </P>
1583 *
1584 * <p>If there is a security manager, its
1585 * {@code checkConnect} method is called
1586 * with the local host name and {@code -1}
1587 * as its arguments to see if the operation is allowed.
1588 * If the operation is not allowed, an InetAddress representing
1589 * the loopback address is returned.
1590 *
1591 * @return the address of the local host.
1592 *
1593 * @throws UnknownHostException if the local host name could not
1594 * be resolved into an address.
1595 *
1596 * @see SecurityManager#checkConnect
1597 * @see java.net.InetAddress#getByName(java.lang.String)
1598 */
1599 public static InetAddress getLocalHost() throws UnknownHostException {
1600
1601 SecurityManager security = System.getSecurityManager();
1602 try {
1603 // is cached data still valid?
1604 CachedLocalHost clh = cachedLocalHost;
1605 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1606 if (security != null) {
1607 security.checkConnect(clh.host, -1);
1608 }
1609 return clh.addr;
1610 }
1611
1612 String local = impl.getLocalHostName();
1613
1614 if (security != null) {
1615 security.checkConnect(local, -1);
1616 }
1617
1618 InetAddress localAddr;
1619 if (local.equals("localhost")) {
1620 // shortcut for "localhost" host name
1621 localAddr = impl.loopbackAddress();
1622 } else {
1623 // call getAllByName0 without security checks and
1624 // without using cached data
1625 try {
1626 localAddr = getAllByName0(local, null, false, false)[0];
1627 } catch (UnknownHostException uhe) {
1628 // Rethrow with a more informative error message.
1629 UnknownHostException uhe2 =
1630 new UnknownHostException(local + ": " +
1631 uhe.getMessage());
1632 uhe2.initCause(uhe);
1633 throw uhe2;
1634 }
1635 }
1636 cachedLocalHost = new CachedLocalHost(local, localAddr);
1637 return localAddr;
1638 } catch (java.lang.SecurityException e) {
1639 return impl.loopbackAddress();
1640 }
1641 }
1642
1643 /**
1644 * Perform class load-time initializations.
1645 */
1646 private static native void init();
1647
1648
1649 /*
1650 * Returns the InetAddress representing anyLocalAddress
1651 * (typically 0.0.0.0 or ::0)
1652 */
1653 static InetAddress anyLocalAddress() {
1654 return impl.anyLocalAddress();
1655 }
1656
1657 /*
1658 * Load and instantiate an underlying impl class
1659 */
1660 static InetAddressImpl loadImpl(String implName) {
1661 Object impl = null;
1662
1663 /*
1664 * Property "impl.prefix" will be prepended to the classname
1665 * of the implementation object we instantiate, to which we
1666 * delegate the real work (like native methods). This
1667 * property can vary across implementations of the java.
1668 * classes. The default is an empty String "".
1669 */
1670 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
1671 try {
1672 @SuppressWarnings("deprecation")
1673 Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
1674 impl = tmp;
1675 } catch (ClassNotFoundException e) {
1676 System.err.println("Class not found: java.net." + prefix +
1677 implName + ":\ncheck impl.prefix property " +
1678 "in your properties file.");
1679 } catch (InstantiationException e) {
1680 System.err.println("Could not instantiate: java.net." + prefix +
1681 implName + ":\ncheck impl.prefix property " +
1682 "in your properties file.");
1683 } catch (IllegalAccessException e) {
1684 System.err.println("Cannot access class: java.net." + prefix +
1685 implName + ":\ncheck impl.prefix property " +
1686 "in your properties file.");
1687 }
1688
1689 if (impl == null) {
1690 try {
1691 @SuppressWarnings("deprecation")
1692 Object tmp = Class.forName(implName).newInstance();
1693 impl = tmp;
1694 } catch (Exception e) {
1695 throw new Error("System property impl.prefix incorrect");
1696 }
1697 }
1698
1699 return (InetAddressImpl) impl;
1700 }
1701
1702 @java.io.Serial
1703 private void readObjectNoData () {
1704 if (getClass().getClassLoader() != null) {
1705 throw new SecurityException ("invalid address type");
1706 }
1707 }
1708
1709 private static final jdk.internal.misc.Unsafe UNSAFE
1710 = jdk.internal.misc.Unsafe.getUnsafe();
1711 private static final long FIELDS_OFFSET
1712 = UNSAFE.objectFieldOffset(InetAddress.class, "holder");
1713
1714 @java.io.Serial
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 if (family != IPv4 && family != IPv6) {
1725 throw new InvalidObjectException("invalid address family type: " + family);
1726 }
1727 InetAddressHolder h = new InetAddressHolder(host, address, family);
1728 UNSAFE.putReference(this, FIELDS_OFFSET, h);
1729 }
1730
1731 /* needed because the serializable fields no longer exist */
1732
1733 /**
1734 * @serialField hostName String
1735 * @serialField address int
1736 * @serialField family int
1737 */
1738 @java.io.Serial
1739 private static final ObjectStreamField[] serialPersistentFields = {
1740 new ObjectStreamField("hostName", String.class),
1741 new ObjectStreamField("address", int.class),
1742 new ObjectStreamField("family", int.class),
1743 };
1744
1745 @java.io.Serial
1746 private void writeObject (ObjectOutputStream s) throws
1747 IOException {
1748 if (getClass().getClassLoader() != null) {
1749 throw new SecurityException ("invalid address type");
1750 }
1751 PutField pf = s.putFields();
1752 pf.put("hostName", holder().getHostName());
1753 pf.put("address", holder().getAddress());
1754 pf.put("family", holder().getFamily());
1755 s.writeFields();
1756 }
1757 }
1758
1759 /*
1760 * Simple factory to create the impl
1761 */
1762 class InetAddressImplFactory {
1763
1764 static InetAddressImpl create() {
1765 return InetAddress.loadImpl(isIPv6Supported() ?
1766 "Inet6AddressImpl" : "Inet4AddressImpl");
1767 }
1768
1769 static native boolean isIPv6Supported();
1770 }