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.List;
29 import java.util.NavigableSet;
30 import java.util.ArrayList;
31 import java.util.Objects;
32 import java.util.Scanner;
33 import java.io.File;
34 import java.io.ObjectStreamException;
35 import java.io.ObjectStreamField;
36 import java.io.IOException;
37 import java.io.InvalidObjectException;
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 import java.util.Arrays;
48
49 import jdk.internal.access.JavaNetInetAddressAccess;
50 import jdk.internal.access.SharedSecrets;
51 import sun.security.action.*;
52 import sun.net.InetAddressCachePolicy;
53 import sun.net.util.IPAddressUtil;
54 import sun.nio.cs.UTF_8;
55
56 /**
57 * This class represents an Internet Protocol (IP) address.
58 *
59 * <p> An IP address is either a 32-bit or 128-bit unsigned number
60 * used by IP, a lower-level protocol on which protocols like UDP and
61 * TCP are built. The IP address architecture is defined by <a
62 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790:
63 * Assigned Numbers</i></a>, <a
64 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918:
65 * Address Allocation for Private Internets</i></a>, <a
66 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365:
67 * Administratively Scoped IP Multicast</i></a>, and <a
68 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP
69 * Version 6 Addressing Architecture</i></a>. An instance of an
70 * InetAddress consists of an IP address and possibly its
71 * corresponding host name (depending on whether it is constructed
72 * with a host name or whether it has already done reverse host name
73 * resolution).
74 *
75 * <h2> Address types </h2>
76 *
77 * <table class="striped" style="margin-left:2em">
78 * <caption style="display:none">Description of unicast and multicast address types</caption>
79 * <thead>
80 * <tr><th scope="col">Address Type</th><th scope="col">Description</th></tr>
81 * </thead>
82 * <tbody>
83 * <tr><th scope="row" style="vertical-align:top">unicast</th>
84 * <td>An identifier for a single interface. A packet sent to
85 * a unicast address is delivered to the interface identified by
86 * that address.
87 *
88 * <p> The Unspecified Address -- Also called anylocal or wildcard
89 * address. It must never be assigned to any node. It indicates the
90 * absence of an address. One example of its use is as the target of
91 * bind, which allows a server to accept a client connection on any
92 * interface, in case the server host has multiple interfaces.
93 *
94 * <p> The <i>unspecified</i> address must not be used as
95 * the destination address of an IP packet.
96 *
97 * <p> The <i>Loopback</i> Addresses -- This is the address
98 * assigned to the loopback interface. Anything sent to this
99 * IP address loops around and becomes IP input on the local
100 * host. This address is often used when testing a
101 * client.</td></tr>
102 * <tr><th scope="row" style="vertical-align:top">multicast</th>
103 * <td>An identifier for a set of interfaces (typically belonging
104 * to different nodes). A packet sent to a multicast address is
105 * delivered to all interfaces identified by that address.</td></tr>
106 * </tbody>
107 * </table>
108 *
109 * <h3> IP address scope </h3>
110 *
111 * <p> <i>Link-local</i> addresses are designed to be used for addressing
112 * on a single link for purposes such as auto-address configuration,
113 * neighbor discovery, or when no routers are present.
114 *
115 * <p> <i>Site-local</i> addresses are designed to be used for addressing
116 * inside of a site without the need for a global prefix.
117 *
118 * <p> <i>Global</i> addresses are unique across the internet.
119 *
120 * <h3> Textual representation of IP addresses </h3>
121 *
122 * The textual representation of an IP address is address family specific.
123 *
124 * <p>
125 *
126 * For IPv4 address format, please refer to <A
127 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6
128 * address format, please refer to <A
129 * HREF="Inet6Address.html#format">Inet6Address#format</A>.
130 *
131 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of
132 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P>
133 *
134 * <h3> Host Name Resolution </h3>
135 *
136 * Host name-to-IP address <i>resolution</i> is accomplished through
137 * the use of a combination of local machine configuration information
138 * and network naming services such as the Domain Name System (DNS)
139 * and Network Information Service(NIS). The particular naming
140 * services(s) being used is by default the local machine configured
141 * one. For any host name, its corresponding IP address is returned.
142 *
143 * <p> <i>Reverse name resolution</i> means that for any IP address,
144 * the host associated with the IP address is returned.
145 *
146 * <p> The InetAddress class provides methods to resolve host names to
147 * their IP addresses and vice versa.
148 *
149 * <h3> InetAddress Caching </h3>
150 *
151 * The InetAddress class has a cache to store successful as well as
152 * unsuccessful host name resolutions.
153 *
154 * <p> By default, when a security manager is installed, in order to
155 * protect against DNS spoofing attacks,
156 * the result of positive host name resolutions are
157 * cached forever. When a security manager is not installed, the default
158 * behavior is to cache entries for a finite (implementation dependent)
159 * period of time. The result of unsuccessful host
160 * name resolution is cached for a very short period of time (10
161 * seconds) to improve performance.
162 *
163 * <p> If the default behavior is not desired, then a Java security property
164 * can be set to a different Time-to-live (TTL) value for positive
165 * caching. Likewise, a system admin can configure a different
166 * negative caching TTL value when needed.
167 *
168 * <p> Two Java security properties control the TTL values used for
169 * positive and negative host name resolution caching:
170 *
171 * <dl style="margin-left:2em">
172 * <dt><b>networkaddress.cache.ttl</b></dt>
173 * <dd>Indicates the caching policy for successful name lookups from
174 * the name service. The value is specified as an integer to indicate
175 * the number of seconds to cache the successful lookup. The default
176 * setting is to cache for an implementation specific period of time.
177 * <p>
178 * A value of -1 indicates "cache forever".
179 * </dd>
180 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt>
181 * <dd>Indicates the caching policy for un-successful name lookups
182 * from the name service. The value is specified as an integer to
183 * indicate the number of seconds to cache the failure for
184 * un-successful lookups.
185 * <p>
186 * A value of 0 indicates "never cache".
187 * A value of -1 indicates "cache forever".
188 * </dd>
189 * </dl>
190 *
191 * @author Chris Warth
192 * @see java.net.InetAddress#getByAddress(byte[])
193 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
194 * @see java.net.InetAddress#getAllByName(java.lang.String)
195 * @see java.net.InetAddress#getByName(java.lang.String)
196 * @see java.net.InetAddress#getLocalHost()
197 * @since 1.0
198 */
199 public class InetAddress implements java.io.Serializable {
200
201 @Native static final int PREFER_IPV4_VALUE = 0;
202 @Native static final int PREFER_IPV6_VALUE = 1;
203 @Native static final int PREFER_SYSTEM_VALUE = 2;
204
205 /**
206 * Specify the address family: Internet Protocol, Version 4
207 * @since 1.4
208 */
209 @Native static final int IPv4 = 1;
210
211 /**
212 * Specify the address family: Internet Protocol, Version 6
213 * @since 1.4
214 */
215 @Native static final int IPv6 = 2;
216
217 /* Specify address family preference */
218 static transient final int preferIPv6Address;
219
220 static class InetAddressHolder {
221 /**
222 * Reserve the original application specified hostname.
223 *
224 * The original hostname is useful for domain-based endpoint
225 * identification (see RFC 2818 and RFC 6125). If an address
226 * was created with a raw IP address, a reverse name lookup
227 * may introduce endpoint identification security issue via
228 * DNS forging.
229 *
230 * Oracle JSSE provider is using this original hostname, via
231 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
232 *
233 * Note: May define a new public method in the future if necessary.
234 */
235 String originalHostName;
236
237 InetAddressHolder() {}
238
239 InetAddressHolder(String hostName, int address, int family) {
240 this.originalHostName = hostName;
241 this.hostName = hostName;
242 this.address = address;
243 this.family = family;
244 }
245
246 void init(String hostName, int family) {
247 this.originalHostName = hostName;
248 this.hostName = hostName;
249 if (family != -1) {
250 this.family = family;
251 }
252 }
253
254 String hostName;
255
256 String getHostName() {
257 return hostName;
258 }
259
260 String getOriginalHostName() {
261 return originalHostName;
262 }
263
264 /**
265 * Holds a 32-bit IPv4 address.
266 */
267 int address;
268
269 int getAddress() {
270 return address;
271 }
272
273 /**
274 * Specifies the address family type, for instance, '1' for IPv4
275 * addresses, and '2' for IPv6 addresses.
276 */
277 int family;
278
279 int getFamily() {
280 return family;
281 }
282 }
283
284 /* Used to store the serializable fields of InetAddress */
285 final transient InetAddressHolder holder;
286
287 InetAddressHolder holder() {
288 return holder;
289 }
290
291 /* Used to store the name service provider */
292 private static transient NameService nameService;
293
294 /**
295 * Used to store the best available hostname.
296 * Lazily initialized via a data race; safe because Strings are immutable.
297 */
298 private transient String canonicalHostName = null;
299
300 /** use serialVersionUID from JDK 1.0.2 for interoperability */
301 @java.io.Serial
302 private static final long serialVersionUID = 3286316764910316507L;
303
304 /*
305 * Load net library into runtime, and perform initializations.
306 */
307 static {
308 String str = GetPropertyAction.privilegedGetProperty("java.net.preferIPv6Addresses");
309 if (str == null) {
310 preferIPv6Address = PREFER_IPV4_VALUE;
311 } else if (str.equalsIgnoreCase("true")) {
312 preferIPv6Address = PREFER_IPV6_VALUE;
313 } else if (str.equalsIgnoreCase("false")) {
314 preferIPv6Address = PREFER_IPV4_VALUE;
315 } else if (str.equalsIgnoreCase("system")) {
316 preferIPv6Address = PREFER_SYSTEM_VALUE;
317 } else {
318 preferIPv6Address = PREFER_IPV4_VALUE;
319 }
320 jdk.internal.loader.BootLoader.loadLibrary("net");
321 SharedSecrets.setJavaNetInetAddressAccess(
322 new JavaNetInetAddressAccess() {
323 public String getOriginalHostName(InetAddress ia) {
324 return ia.holder.getOriginalHostName();
325 }
326
327 public InetAddress getByName(String hostName,
328 InetAddress hostAddress)
329 throws UnknownHostException
330 {
331 return InetAddress.getByName(hostName, hostAddress);
332 }
333
334 public int addressValue(Inet4Address inet4Address) {
335 return inet4Address.addressValue();
336 }
337
338 public byte[] addressBytes(Inet6Address inet6Address) {
339 return inet6Address.addressBytes();
340 }
341 }
342 );
343 init();
344 }
345
346 /**
347 * Constructor for the Socket.accept() method.
348 * This creates an empty InetAddress, which is filled in by
349 * the accept() method. This InetAddress, however, is not
350 * put in the address cache, since it is not created by name.
351 */
352 InetAddress() {
353 holder = new InetAddressHolder();
354 }
355
356 /**
357 * Replaces the de-serialized object with an Inet4Address object.
358 *
359 * @return the alternate object to the de-serialized object.
360 *
361 * @throws ObjectStreamException if a new object replacing this
362 * object could not be created
363 */
364 @java.io.Serial
365 private Object readResolve() throws ObjectStreamException {
366 // will replace the deserialized 'this' object
367 return new Inet4Address(holder().getHostName(), holder().getAddress());
368 }
369
370 /**
371 * Utility routine to check if the InetAddress is an
372 * IP multicast address.
373 * @return a {@code boolean} indicating if the InetAddress is
374 * an IP multicast address
375 * @since 1.1
376 */
377 public boolean isMulticastAddress() {
378 return false;
379 }
380
381 /**
382 * Utility routine to check if the InetAddress is a wildcard address.
383 * @return a {@code boolean} indicating if the InetAddress is
384 * a wildcard address.
385 * @since 1.4
386 */
387 public boolean isAnyLocalAddress() {
388 return false;
389 }
390
391 /**
392 * Utility routine to check if the InetAddress is a loopback address.
393 *
394 * @return a {@code boolean} indicating if the InetAddress is
395 * a loopback address; or false otherwise.
396 * @since 1.4
397 */
398 public boolean isLoopbackAddress() {
399 return false;
400 }
401
402 /**
403 * Utility routine to check if the InetAddress is an link local address.
404 *
405 * @return a {@code boolean} indicating if the InetAddress is
406 * a link local address; or false if address is not a link local unicast address.
407 * @since 1.4
408 */
409 public boolean isLinkLocalAddress() {
410 return false;
411 }
412
413 /**
414 * Utility routine to check if the InetAddress is a site local address.
415 *
416 * @return a {@code boolean} indicating if the InetAddress is
417 * a site local address; or false if address is not a site local unicast address.
418 * @since 1.4
419 */
420 public boolean isSiteLocalAddress() {
421 return false;
422 }
423
424 /**
425 * Utility routine to check if the multicast address has global scope.
426 *
427 * @return a {@code boolean} indicating if the address has
428 * is a multicast address of global scope, false if it is not
429 * of global scope or it is not a multicast address
430 * @since 1.4
431 */
432 public boolean isMCGlobal() {
433 return false;
434 }
435
436 /**
437 * Utility routine to check if the multicast address has node scope.
438 *
439 * @return a {@code boolean} indicating if the address has
440 * is a multicast address of node-local scope, false if it is not
441 * of node-local scope or it is not a multicast address
442 * @since 1.4
443 */
444 public boolean isMCNodeLocal() {
445 return false;
446 }
447
448 /**
449 * Utility routine to check if the multicast address has link scope.
450 *
451 * @return a {@code boolean} indicating if the address has
452 * is a multicast address of link-local scope, false if it is not
453 * of link-local scope or it is not a multicast address
454 * @since 1.4
455 */
456 public boolean isMCLinkLocal() {
457 return false;
458 }
459
460 /**
461 * Utility routine to check if the multicast address has site scope.
462 *
463 * @return a {@code boolean} indicating if the address has
464 * is a multicast address of site-local scope, false if it is not
465 * of site-local scope or it is not a multicast address
466 * @since 1.4
467 */
468 public boolean isMCSiteLocal() {
469 return false;
470 }
471
472 /**
473 * Utility routine to check if the multicast address has organization scope.
474 *
475 * @return a {@code boolean} indicating if the address has
476 * is a multicast address of organization-local scope,
477 * false if it is not of organization-local scope
478 * or it is not a multicast address
479 * @since 1.4
480 */
481 public boolean isMCOrgLocal() {
482 return false;
483 }
484
485
486 /**
487 * Test whether that address is reachable. Best effort is made by the
488 * implementation to try to reach the host, but firewalls and server
489 * configuration may block requests resulting in a unreachable status
490 * while some specific ports may be accessible.
491 * A typical implementation will use ICMP ECHO REQUESTs if the
492 * privilege can be obtained, otherwise it will try to establish
493 * a TCP connection on port 7 (Echo) of the destination host.
494 * <p>
495 * The timeout value, in milliseconds, indicates the maximum amount of time
496 * the try should take. If the operation times out before getting an
497 * answer, the host is deemed unreachable. A negative value will result
498 * in an IllegalArgumentException being thrown.
499 *
500 * @param timeout the time, in milliseconds, before the call aborts
501 * @return a {@code boolean} indicating if the address is reachable.
502 * @throws IOException if a network error occurs
503 * @throws IllegalArgumentException if {@code timeout} is negative.
504 * @since 1.5
505 */
506 public boolean isReachable(int timeout) throws IOException {
507 return isReachable(null, 0 , timeout);
508 }
509
510 /**
511 * Test whether that address is reachable. Best effort is made by the
512 * implementation to try to reach the host, but firewalls and server
513 * configuration may block requests resulting in a unreachable status
514 * while some specific ports may be accessible.
515 * A typical implementation will use ICMP ECHO REQUESTs if the
516 * privilege can be obtained, otherwise it will try to establish
517 * a TCP connection on port 7 (Echo) of the destination host.
518 * <p>
519 * The {@code network interface} and {@code ttl} parameters
520 * let the caller specify which network interface the test will go through
521 * and the maximum number of hops the packets should go through.
522 * A negative value for the {@code ttl} will result in an
523 * IllegalArgumentException being thrown.
524 * <p>
525 * The timeout value, in milliseconds, indicates the maximum amount of time
526 * the try should take. If the operation times out before getting an
527 * answer, the host is deemed unreachable. A negative value will result
528 * in an IllegalArgumentException being thrown.
529 *
530 * @param netif the NetworkInterface through which the
531 * test will be done, or null for any interface
532 * @param ttl the maximum numbers of hops to try or 0 for the
533 * default
534 * @param timeout the time, in milliseconds, before the call aborts
535 * @throws IllegalArgumentException if either {@code timeout}
536 * or {@code ttl} are negative.
537 * @return a {@code boolean} indicating if the address is reachable.
538 * @throws IOException if a network error occurs
539 * @since 1.5
540 */
541 public boolean isReachable(NetworkInterface netif, int ttl,
542 int timeout) throws IOException {
543 if (ttl < 0)
544 throw new IllegalArgumentException("ttl can't be negative");
545 if (timeout < 0)
546 throw new IllegalArgumentException("timeout can't be negative");
547
548 return impl.isReachable(this, timeout, netif, ttl);
549 }
550
551 /**
552 * Gets the host name for this IP address.
553 *
554 * <p>If this InetAddress was created with a host name,
555 * this host name will be remembered and returned;
556 * otherwise, a reverse name lookup will be performed
557 * and the result will be returned based on the system
558 * configured name lookup service. If a lookup of the name service
559 * is required, call
560 * {@link #getCanonicalHostName() getCanonicalHostName}.
561 *
562 * <p>If there is a security manager, its
563 * {@code checkConnect} method is first called
564 * with the hostname and {@code -1}
565 * as its arguments to see if the operation is allowed.
566 * If the operation is not allowed, it will return
567 * the textual representation of the IP address.
568 *
569 * @return the host name for this IP address, or if the operation
570 * is not allowed by the security check, the textual
571 * representation of the IP address.
572 *
573 * @see InetAddress#getCanonicalHostName
574 * @see SecurityManager#checkConnect
575 */
576 public String getHostName() {
577 return getHostName(true);
578 }
579
580 /**
581 * Returns the hostname for this address.
582 * If the host is equal to null, then this address refers to any
583 * of the local machine's available network addresses.
584 * this is package private so SocketPermission can make calls into
585 * here without a security check.
586 *
587 * <p>If there is a security manager, this method first
588 * calls its {@code checkConnect} method
589 * with the hostname and {@code -1}
590 * as its arguments to see if the calling code is allowed to know
591 * the hostname for this IP address, i.e., to connect to the host.
592 * If the operation is not allowed, it will return
593 * the textual representation of the IP address.
594 *
595 * @return the host name for this IP address, or if the operation
596 * is not allowed by the security check, the textual
597 * representation of the IP address.
598 *
599 * @param check make security check if true
600 *
601 * @see SecurityManager#checkConnect
602 */
603 String getHostName(boolean check) {
604 if (holder().getHostName() == null) {
605 holder().hostName = InetAddress.getHostFromNameService(this, check);
606 }
607 return holder().getHostName();
608 }
609
610 /**
611 * Gets the fully qualified domain name for this IP address.
612 * Best effort method, meaning we may not be able to return
613 * the FQDN depending on the underlying system configuration.
614 *
615 * <p>If there is a security manager, this method first
616 * calls its {@code checkConnect} method
617 * with the hostname and {@code -1}
618 * as its arguments to see if the calling code is allowed to know
619 * the hostname for this IP address, i.e., to connect to the host.
620 * If the operation is not allowed, it will return
621 * the textual representation of the IP address.
622 *
623 * @return the fully qualified domain name for this IP address,
624 * or if the operation is not allowed by the security check,
625 * the textual representation of the IP address.
626 *
627 * @see SecurityManager#checkConnect
628 *
629 * @since 1.4
630 */
631 public String getCanonicalHostName() {
632 String value = canonicalHostName;
633 if (value == null)
634 canonicalHostName = value =
635 InetAddress.getHostFromNameService(this, true);
636 return value;
637 }
638
639 /**
640 * Returns the hostname for this address.
641 *
642 * <p>If there is a security manager, this method first
643 * calls its {@code checkConnect} method
644 * with the hostname and {@code -1}
645 * as its arguments to see if the calling code is allowed to know
646 * the hostname for this IP address, i.e., to connect to the host.
647 * If the operation is not allowed, it will return
648 * the textual representation of the IP address.
649 *
650 * @return the host name for this IP address, or if the operation
651 * is not allowed by the security check, the textual
652 * representation of the IP address.
653 *
654 * @param check make security check if true
655 *
656 * @see SecurityManager#checkConnect
657 */
658 private static String getHostFromNameService(InetAddress addr, boolean check) {
659 String host = null;
660 try {
661 // first lookup the hostname
662 host = nameService.getHostByAddr(addr.getAddress());
663
664 /* check to see if calling code is allowed to know
665 * the hostname for this IP address, ie, connect to the host
666 */
667 if (check) {
668 SecurityManager sec = System.getSecurityManager();
669 if (sec != null) {
670 sec.checkConnect(host, -1);
671 }
672 }
673
674 /* now get all the IP addresses for this hostname,
675 * and make sure one of them matches the original IP
676 * address. We do this to try and prevent spoofing.
677 */
678
679 InetAddress[] arr = InetAddress.getAllByName0(host, check);
680 boolean ok = false;
681
682 if(arr != null) {
683 for(int i = 0; !ok && i < arr.length; i++) {
684 ok = addr.equals(arr[i]);
685 }
686 }
687
688 //XXX: if it looks a spoof just return the address?
689 if (!ok) {
690 host = addr.getHostAddress();
691 return host;
692 }
693 } catch (SecurityException e) {
694 host = addr.getHostAddress();
695 } catch (UnknownHostException e) {
696 host = addr.getHostAddress();
697 // let next provider resolve the hostname
698 }
699 return host;
700 }
701
702 /**
703 * Returns the raw IP address of this {@code InetAddress}
704 * object. The result is in network byte order: the highest order
705 * byte of the address is in {@code getAddress()[0]}.
706 *
707 * @return the raw IP address of this object.
708 */
709 public byte[] getAddress() {
710 return null;
711 }
712
713 /**
714 * Returns the IP address string in textual presentation.
715 *
716 * @return the raw IP address in a string format.
717 * @since 1.0.2
718 */
719 public String getHostAddress() {
720 return null;
721 }
722
723 /**
724 * Returns a hashcode for this IP address.
725 *
726 * @return a hash code value for this IP address.
727 */
728 public int hashCode() {
729 return -1;
730 }
731
732 /**
733 * Compares this object against the specified object.
734 * The result is {@code true} if and only if the argument is
735 * not {@code null} and it represents the same IP address as
736 * this object.
737 * <p>
738 * Two instances of {@code InetAddress} represent the same IP
739 * address if the length of the byte arrays returned by
740 * {@code getAddress} is the same for both, and each of the
741 * array components is the same for the byte arrays.
742 *
743 * @param obj the object to compare against.
744 * @return {@code true} if the objects are the same;
745 * {@code false} otherwise.
746 * @see java.net.InetAddress#getAddress()
747 */
748 public boolean equals(Object obj) {
749 return false;
750 }
751
752 /**
753 * Converts this IP address to a {@code String}. The
754 * string returned is of the form: hostname / literal IP
755 * address.
756 *
757 * If the host name is unresolved, no reverse name service lookup
758 * is performed. The hostname part will be represented by an empty string.
759 *
760 * @return a string representation of this IP address.
761 */
762 public String toString() {
763 String hostName = holder().getHostName();
764 return Objects.toString(hostName, "")
765 + "/" + getHostAddress();
766 }
767
768 // mapping from host name to Addresses - either NameServiceAddresses (while
769 // still being looked-up by NameService(s)) or CachedAddresses when cached
770 private static final ConcurrentMap<String, Addresses> cache =
771 new ConcurrentHashMap<>();
772
773 // CachedAddresses that have to expire are kept ordered in this NavigableSet
774 // which is scanned on each access
775 private static final NavigableSet<CachedAddresses> expirySet =
776 new ConcurrentSkipListSet<>();
777
778 // common interface
779 private interface Addresses {
780 InetAddress[] get() throws UnknownHostException;
781 }
782
783 // a holder for cached addresses with required metadata
784 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
785 private static final AtomicLong seq = new AtomicLong();
786 final String host;
787 final InetAddress[] inetAddresses;
788 final long expiryTime; // time of expiry (in terms of System.nanoTime())
789 final long id = seq.incrementAndGet(); // each instance is unique
790
791 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
792 this.host = host;
793 this.inetAddresses = inetAddresses;
794 this.expiryTime = expiryTime;
795 }
796
797 @Override
798 public InetAddress[] get() throws UnknownHostException {
799 if (inetAddresses == null) {
800 throw new UnknownHostException(host);
801 }
802 return inetAddresses;
803 }
804
805 @Override
806 public int compareTo(CachedAddresses other) {
807 // natural order is expiry time -
808 // compare difference of expiry times rather than
809 // expiry times directly, to avoid possible overflow.
810 // (see System.nanoTime() recommendations...)
811 long diff = this.expiryTime - other.expiryTime;
812 if (diff < 0L) return -1;
813 if (diff > 0L) return 1;
814 // ties are broken using unique id
815 return Long.compare(this.id, other.id);
816 }
817 }
818
819 // a name service lookup based Addresses implementation which replaces itself
820 // in cache when the result is obtained
821 private static final class NameServiceAddresses implements Addresses {
822 private final String host;
823 private final InetAddress reqAddr;
824
825 NameServiceAddresses(String host, InetAddress reqAddr) {
826 this.host = host;
827 this.reqAddr = reqAddr;
828 }
829
830 @Override
831 public InetAddress[] get() throws UnknownHostException {
832 Addresses addresses;
833 // only one thread is doing lookup to name service
834 // for particular host at any time.
835 synchronized (this) {
836 // re-check that we are still us + re-install us if slot empty
837 addresses = cache.putIfAbsent(host, this);
838 if (addresses == null) {
839 // this can happen when we were replaced by CachedAddresses in
840 // some other thread, then CachedAddresses expired and were
841 // removed from cache while we were waiting for lock...
842 addresses = this;
843 }
844 // still us ?
845 if (addresses == this) {
846 // lookup name services
847 InetAddress[] inetAddresses;
848 UnknownHostException ex;
849 int cachePolicy;
850 try {
851 inetAddresses = getAddressesFromNameService(host, reqAddr);
852 ex = null;
853 cachePolicy = InetAddressCachePolicy.get();
854 } catch (UnknownHostException uhe) {
855 inetAddresses = null;
856 ex = uhe;
857 cachePolicy = InetAddressCachePolicy.getNegative();
858 }
859 // remove or replace us with cached addresses according to cachePolicy
860 if (cachePolicy == InetAddressCachePolicy.NEVER) {
861 cache.remove(host, this);
862 } else {
863 CachedAddresses cachedAddresses = new CachedAddresses(
864 host,
865 inetAddresses,
866 cachePolicy == InetAddressCachePolicy.FOREVER
867 ? 0L
868 // cachePolicy is in [s] - we need [ns]
869 : System.nanoTime() + 1000_000_000L * cachePolicy
870 );
871 if (cache.replace(host, this, cachedAddresses) &&
872 cachePolicy != InetAddressCachePolicy.FOREVER) {
873 // schedule expiry
874 expirySet.add(cachedAddresses);
875 }
876 }
877 if (inetAddresses == null) {
878 throw ex == null ? new UnknownHostException(host) : ex;
879 }
880 return inetAddresses;
881 }
882 // else addresses != this
883 }
884 // delegate to different addresses when we are already replaced
885 // but outside of synchronized block to avoid any chance of dead-locking
886 return addresses.get();
887 }
888 }
889
890 /**
891 * NameService provides host and address lookup service
892 *
893 * @since 9
894 */
895 private interface NameService {
896
897 /**
898 * Lookup a host mapping by name. Retrieve the IP addresses
899 * associated with a host
900 *
901 * @param host the specified hostname
902 * @return array of IP addresses for the requested host
903 * @throws UnknownHostException
904 * if no IP address for the {@code host} could be found
905 */
906 InetAddress[] lookupAllHostAddr(String host)
907 throws UnknownHostException;
908
909 /**
910 * Lookup the host corresponding to the IP address provided
911 *
912 * @param addr byte array representing an IP address
913 * @return {@code String} representing the host name mapping
914 * @throws UnknownHostException
915 * if no host found for the specified IP address
916 */
917 String getHostByAddr(byte[] addr) throws UnknownHostException;
918
919 }
920
921 /**
922 * The default NameService implementation, which delegates to the underlying
923 * OS network libraries to resolve host address mappings.
924 *
925 * @since 9
926 */
927 private static final class PlatformNameService implements NameService {
928
929 public InetAddress[] lookupAllHostAddr(String host)
930 throws UnknownHostException
931 {
932 return impl.lookupAllHostAddr(host);
933 }
934
935 public String getHostByAddr(byte[] addr)
936 throws UnknownHostException
937 {
938 return impl.getHostByAddr(addr);
939 }
940 }
941
942 /**
943 * The HostsFileNameService provides host address mapping
944 * by reading the entries in a hosts file, which is specified by
945 * {@code jdk.net.hosts.file} system property
946 *
947 * <p>The file format is that which corresponds with the /etc/hosts file
948 * IP Address host alias list.
949 *
950 * <p>When the file lookup is enabled it replaces the default NameService
951 * implementation
952 *
953 * @since 9
954 */
955 private static final class HostsFileNameService implements NameService {
956
957 private static final InetAddress[] EMPTY_ARRAY = new InetAddress[0];
958
959 // Specify if only IPv4 addresses should be returned by HostsFileService implementation
960 private static final boolean preferIPv4Stack = Boolean.parseBoolean(
961 GetPropertyAction.privilegedGetProperty("java.net.preferIPv4Stack"));
962
963 private final String hostsFile;
964
965 public HostsFileNameService(String hostsFileName) {
966 this.hostsFile = hostsFileName;
967 }
968
969 /**
970 * Lookup the host name corresponding to the IP address provided.
971 * Search the configured host file a host name corresponding to
972 * the specified IP address.
973 *
974 * @param addr byte array representing an IP address
975 * @return {@code String} representing the host name mapping
976 * @throws UnknownHostException
977 * if no host found for the specified IP address
978 */
979 @Override
980 public String getHostByAddr(byte[] addr) throws UnknownHostException {
981 String hostEntry;
982 String host = null;
983
984 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
985 UTF_8.INSTANCE))
986 {
987 while (hostsFileScanner.hasNextLine()) {
988 hostEntry = hostsFileScanner.nextLine();
989 if (!hostEntry.startsWith("#")) {
990 hostEntry = removeComments(hostEntry);
991 String[] mapping = hostEntry.split("\\s+");
992 if (mapping.length >= 2 &&
993 Arrays.equals(addr, createAddressByteArray(mapping[0]))) {
994 host = mapping[1];
995 break;
996 }
997 }
998 }
999 } catch (IOException e) {
1000 throw new UnknownHostException("Unable to resolve address "
1001 + Arrays.toString(addr) + " as hosts file " + hostsFile
1002 + " not found ");
1003 }
1004
1005 if ((host == null) || (host.isEmpty()) || (host.equals(" "))) {
1006 throw new UnknownHostException("Requested address "
1007 + Arrays.toString(addr)
1008 + " resolves to an invalid entry in hosts file "
1009 + hostsFile);
1010 }
1011 return host;
1012 }
1013
1014 /**
1015 * <p>Lookup a host mapping by name. Retrieve the IP addresses
1016 * associated with a host.
1017 *
1018 * <p>Search the configured hosts file for the addresses associated
1019 * with the specified host name.
1020 *
1021 * @param host the specified hostname
1022 * @return array of IP addresses for the requested host
1023 * @throws UnknownHostException
1024 * if no IP address for the {@code host} could be found
1025 */
1026 public InetAddress[] lookupAllHostAddr(String host)
1027 throws UnknownHostException {
1028 String hostEntry;
1029 String addrStr;
1030 byte addr[];
1031 List<InetAddress> inetAddresses = new ArrayList<>();
1032 List<InetAddress> inet4Addresses = new ArrayList<>();
1033 List<InetAddress> inet6Addresses = new ArrayList<>();
1034
1035 // lookup the file and create a list InetAddress for the specified host
1036 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile),
1037 UTF_8.INSTANCE)) {
1038 while (hostsFileScanner.hasNextLine()) {
1039 hostEntry = hostsFileScanner.nextLine();
1040 if (!hostEntry.startsWith("#")) {
1041 hostEntry = removeComments(hostEntry);
1042 if (hostEntry.contains(host)) {
1043 addrStr = extractHostAddr(hostEntry, host);
1044 if ((addrStr != null) && (!addrStr.isEmpty())) {
1045 addr = createAddressByteArray(addrStr);
1046 if (addr != null) {
1047 InetAddress address = InetAddress.getByAddress(host, addr);
1048 inetAddresses.add(address);
1049 if (address instanceof Inet4Address) {
1050 inet4Addresses.add(address);
1051 }
1052 if (address instanceof Inet6Address) {
1053 inet6Addresses.add(address);
1054 }
1055 }
1056 }
1057 }
1058 }
1059 }
1060 } catch (IOException e) {
1061 throw new UnknownHostException("Unable to resolve host " + host
1062 + " as hosts file " + hostsFile + " not found ");
1063 }
1064
1065 List<InetAddress> res;
1066 // If "preferIPv4Stack" system property is set to "true" then return
1067 // only IPv4 addresses
1068 if (preferIPv4Stack) {
1069 res = inet4Addresses;
1070 } else {
1071 // Otherwise, analyse "preferIPv6Addresses" value
1072 res = switch (preferIPv6Address) {
1073 case PREFER_IPV4_VALUE -> concatAddresses(inet4Addresses, inet6Addresses);
1074 case PREFER_IPV6_VALUE -> concatAddresses(inet6Addresses, inet4Addresses);
1075 default -> inetAddresses;
1076 };
1077 }
1078
1079 if (res.isEmpty()) {
1080 throw new UnknownHostException("Unable to resolve host " + host
1081 + " in hosts file " + hostsFile);
1082 }
1083 return res.toArray(EMPTY_ARRAY);
1084 }
1085
1086 private static List<InetAddress> concatAddresses(List<InetAddress> firstPart,
1087 List<InetAddress> secondPart) {
1088 List<InetAddress> result = new ArrayList<>(firstPart);
1089 result.addAll(secondPart);
1090 return result;
1091 }
1092
1093 private String removeComments(String hostsEntry) {
1094 String filteredEntry = hostsEntry;
1095 int hashIndex;
1096
1097 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1098 filteredEntry = hostsEntry.substring(0, hashIndex);
1099 }
1100 return filteredEntry;
1101 }
1102
1103 private byte [] createAddressByteArray(String addrStr) {
1104 byte[] addrArray;
1105 // check if IPV4 address - most likely
1106 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr);
1107 if (addrArray == null) {
1108 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
1109 }
1110 return addrArray;
1111 }
1112
1113 /** host to ip address mapping */
1114 private String extractHostAddr(String hostEntry, String host) {
1115 String[] mapping = hostEntry.split("\\s+");
1116 String hostAddr = null;
1117
1118 if (mapping.length >= 2) {
1119 // look at the host aliases
1120 for (int i = 1; i < mapping.length; i++) {
1121 if (mapping[i].equalsIgnoreCase(host)) {
1122 hostAddr = mapping[0];
1123 }
1124 }
1125 }
1126 return hostAddr;
1127 }
1128 }
1129
1130 static final InetAddressImpl impl;
1131
1132 static {
1133 // create the impl
1134 impl = InetAddressImplFactory.create();
1135
1136 // create name service
1137 nameService = createNameService();
1138 }
1139
1140 /**
1141 * Create an instance of the NameService interface based on
1142 * the setting of the {@code jdk.net.hosts.file} system property.
1143 *
1144 * <p>The default NameService is the PlatformNameService, which typically
1145 * delegates name and address resolution calls to the underlying
1146 * OS network libraries.
1147 *
1148 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1149 * system property is set. If the specified file doesn't exist, the name or
1150 * address lookup will result in an UnknownHostException. Thus, non existent
1151 * hosts file is handled as if the file is empty.
1152 *
1153 * @return a NameService
1154 */
1155 private static NameService createNameService() {
1156
1157 String hostsFileName =
1158 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file");
1159 NameService theNameService;
1160 if (hostsFileName != null) {
1161 theNameService = new HostsFileNameService(hostsFileName);
1162 } else {
1163 theNameService = new PlatformNameService();
1164 }
1165 return theNameService;
1166 }
1167
1168 /**
1169 * Creates an InetAddress based on the provided host name and IP address.
1170 * No name service is checked for the validity of the address.
1171 *
1172 * <p> The host name can either be a machine name, such as
1173 * "{@code www.example.com}", or a textual representation of its IP
1174 * address.
1175 * <p> No validity checking is done on the host name either.
1176 *
1177 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1178 * will be returned; otherwise, an instance of Inet6Address
1179 * will be returned.
1180 *
1181 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1182 * must be 16 bytes long
1183 *
1184 * @param host the specified host
1185 * @param addr the raw IP address in network byte order
1186 * @return an InetAddress object created from the raw IP address.
1187 * @throws UnknownHostException if IP address is of illegal length
1188 * @since 1.4
1189 */
1190 public static InetAddress getByAddress(String host, byte[] addr)
1191 throws UnknownHostException {
1192 if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
1193 if (host.charAt(host.length()-1) == ']') {
1194 host = host.substring(1, host.length() -1);
1195 }
1196 }
1197 if (addr != null) {
1198 if (addr.length == Inet4Address.INADDRSZ) {
1199 return new Inet4Address(host, addr);
1200 } else if (addr.length == Inet6Address.INADDRSZ) {
1201 byte[] newAddr
1202 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1203 if (newAddr != null) {
1204 return new Inet4Address(host, newAddr);
1205 } else {
1206 return new Inet6Address(host, addr);
1207 }
1208 }
1209 }
1210 throw new UnknownHostException("addr is of illegal length");
1211 }
1212
1213
1214 /**
1215 * Determines the IP address of a host, given the host's name.
1216 *
1217 * <p> The host name can either be a machine name, such as
1218 * "{@code www.example.com}", or a textual representation of its
1219 * IP address. If a literal IP address is supplied, only the
1220 * validity of the address format is checked.
1221 *
1222 * <p> For {@code host} specified in literal IPv6 address,
1223 * either the form defined in RFC 2732 or the literal IPv6 address
1224 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1225 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1226 * scoped addresses.
1227 *
1228 * <p> If the host is {@code null} or {@code host.length()} is equal
1229 * to zero, then an {@code InetAddress} representing an address of the
1230 * loopback interface is returned.
1231 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1232 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1233 * section 2.5.3.
1234 *
1235 * <p> If there is a security manager, and {@code host} is not {@code null}
1236 * or {@code host.length() } is not equal to zero, the security manager's
1237 * {@code checkConnect} method is called with the hostname and {@code -1}
1238 * as its arguments to determine if the operation is allowed.
1239 *
1240 * @param host the specified host, or {@code null}.
1241 * @return an IP address for the given host name.
1242 * @throws UnknownHostException if no IP address for the
1243 * {@code host} could be found, or if a scope_id was specified
1244 * for a global IPv6 address.
1245 * @throws SecurityException if a security manager exists
1246 * and its checkConnect method doesn't allow the operation
1247 */
1248 public static InetAddress getByName(String host)
1249 throws UnknownHostException {
1250 return InetAddress.getAllByName(host)[0];
1251 }
1252
1253 // called from deployment cache manager
1254 private static InetAddress getByName(String host, InetAddress reqAddr)
1255 throws UnknownHostException {
1256 return InetAddress.getAllByName(host, reqAddr)[0];
1257 }
1258
1259 /**
1260 * Given the name of a host, returns an array of its IP addresses,
1261 * based on the configured name service on the system.
1262 *
1263 * <p> The host name can either be a machine name, such as
1264 * "{@code www.example.com}", or a textual representation of its IP
1265 * address. If a literal IP address is supplied, only the
1266 * validity of the address format is checked.
1267 *
1268 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1269 * either the form defined in RFC 2732 or the literal IPv6 address
1270 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1271 * also be qualified by appending a scoped zone identifier or scope_id.
1272 * The syntax and usage of scope_ids is described
1273 * <a href="Inet6Address.html#scoped">here</a>.
1274 *
1275 * <p> If the host is {@code null} or {@code host.length()} is equal
1276 * to zero, then an {@code InetAddress} representing an address of the
1277 * loopback interface is returned.
1278 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1279 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1280 * section 2.5.3. </p>
1281 *
1282 * <p> If there is a security manager, and {@code host} is not {@code null}
1283 * or {@code host.length() } is not equal to zero, the security manager's
1284 * {@code checkConnect} method is called with the hostname and {@code -1}
1285 * as its arguments to determine if the operation is allowed.
1286 *
1287 * @param host the name of the host, or {@code null}.
1288 * @return an array of all the IP addresses for a given host name.
1289 *
1290 * @throws UnknownHostException if no IP address for the
1291 * {@code host} could be found, or if a scope_id was specified
1292 * for a global IPv6 address.
1293 * @throws SecurityException if a security manager exists and its
1294 * {@code checkConnect} method doesn't allow the operation.
1295 *
1296 * @see SecurityManager#checkConnect
1297 */
1298 public static InetAddress[] getAllByName(String host)
1299 throws UnknownHostException {
1300 return getAllByName(host, null);
1301 }
1302
1303 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1304 throws UnknownHostException {
1305
1306 if (host == null || host.isEmpty()) {
1307 InetAddress[] ret = new InetAddress[1];
1308 ret[0] = impl.loopbackAddress();
1309 return ret;
1310 }
1311
1312 boolean ipv6Expected = false;
1313 if (host.charAt(0) == '[') {
1314 // This is supposed to be an IPv6 literal
1315 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1316 host = host.substring(1, host.length() -1);
1317 ipv6Expected = true;
1318 } else {
1319 // This was supposed to be a IPv6 address, but it's not!
1320 throw new UnknownHostException(host + ": invalid IPv6 address");
1321 }
1322 }
1323
1324 // if host is an IP address, we won't do further lookup
1325 if (Character.digit(host.charAt(0), 16) != -1
1326 || (host.charAt(0) == ':')) {
1327 byte[] addr = null;
1328 int numericZone = -1;
1329 String ifname = null;
1330 // see if it is IPv4 address
1331 addr = IPAddressUtil.textToNumericFormatV4(host);
1332 if (addr == null) {
1333 // This is supposed to be an IPv6 literal
1334 // Check if a numeric or string zone id is present
1335 int pos;
1336 if ((pos=host.indexOf ('%')) != -1) {
1337 numericZone = checkNumericZone (host);
1338 if (numericZone == -1) { /* remainder of string must be an ifname */
1339 ifname = host.substring (pos+1);
1340 }
1341 }
1342 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1343 throw new UnknownHostException(host + ": invalid IPv6 address");
1344 }
1345 } else if (ipv6Expected) {
1346 // Means an IPv4 literal between brackets!
1347 throw new UnknownHostException("["+host+"]");
1348 }
1349 InetAddress[] ret = new InetAddress[1];
1350 if(addr != null) {
1351 if (addr.length == Inet4Address.INADDRSZ) {
1352 ret[0] = new Inet4Address(null, addr);
1353 } else {
1354 if (ifname != null) {
1355 ret[0] = new Inet6Address(null, addr, ifname);
1356 } else {
1357 ret[0] = new Inet6Address(null, addr, numericZone);
1358 }
1359 }
1360 return ret;
1361 }
1362 } else if (ipv6Expected) {
1363 // We were expecting an IPv6 Literal, but got something else
1364 throw new UnknownHostException("["+host+"]");
1365 }
1366 return getAllByName0(host, reqAddr, true, true);
1367 }
1368
1369 /**
1370 * Returns the loopback address.
1371 * <p>
1372 * The InetAddress returned will represent the IPv4
1373 * loopback address, 127.0.0.1, or the IPv6 loopback
1374 * address, ::1. The IPv4 loopback address returned
1375 * is only one of many in the form 127.*.*.*
1376 *
1377 * @return the InetAddress loopback instance.
1378 * @since 1.7
1379 */
1380 public static InetAddress getLoopbackAddress() {
1381 return impl.loopbackAddress();
1382 }
1383
1384
1385 /**
1386 * check if the literal address string has %nn appended
1387 * returns -1 if not, or the numeric value otherwise.
1388 *
1389 * %nn may also be a string that represents the displayName of
1390 * a currently available NetworkInterface.
1391 */
1392 private static int checkNumericZone (String s) throws UnknownHostException {
1393 int percent = s.indexOf ('%');
1394 int slen = s.length();
1395 int digit, zone=0;
1396 if (percent == -1) {
1397 return -1;
1398 }
1399 for (int i=percent+1; i<slen; i++) {
1400 char c = s.charAt(i);
1401 if (c == ']') {
1402 if (i == percent+1) {
1403 /* empty per-cent field */
1404 return -1;
1405 }
1406 break;
1407 }
1408 if ((digit = Character.digit (c, 10)) < 0) {
1409 return -1;
1410 }
1411 zone = (zone * 10) + digit;
1412 }
1413 return zone;
1414 }
1415
1416 private static InetAddress[] getAllByName0 (String host)
1417 throws UnknownHostException
1418 {
1419 return getAllByName0(host, true);
1420 }
1421
1422 /**
1423 * package private so SocketPermission can call it
1424 */
1425 static InetAddress[] getAllByName0 (String host, boolean check)
1426 throws UnknownHostException {
1427 return getAllByName0 (host, null, check, true);
1428 }
1429
1430 /**
1431 * Designated lookup method.
1432 *
1433 * @param host host name to look up
1434 * @param reqAddr requested address to be the 1st in returned array
1435 * @param check perform security check
1436 * @param useCache use cached value if not expired else always
1437 * perform name service lookup (and cache the result)
1438 * @return array of InetAddress(es)
1439 * @throws UnknownHostException if host name is not found
1440 */
1441 private static InetAddress[] getAllByName0(String host,
1442 InetAddress reqAddr,
1443 boolean check,
1444 boolean useCache)
1445 throws UnknownHostException {
1446
1447 /* If it gets here it is presumed to be a hostname */
1448
1449 /* make sure the connection to the host is allowed, before we
1450 * give out a hostname
1451 */
1452 if (check) {
1453 SecurityManager security = System.getSecurityManager();
1454 if (security != null) {
1455 security.checkConnect(host, -1);
1456 }
1457 }
1458
1459 // remove expired addresses from cache - expirySet keeps them ordered
1460 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1461 long now = System.nanoTime();
1462 for (CachedAddresses caddrs : expirySet) {
1463 // compare difference of time instants rather than
1464 // time instants directly, to avoid possible overflow.
1465 // (see System.nanoTime() recommendations...)
1466 if ((caddrs.expiryTime - now) < 0L) {
1467 // ConcurrentSkipListSet uses weakly consistent iterator,
1468 // so removing while iterating is OK...
1469 if (expirySet.remove(caddrs)) {
1470 // ... remove from cache
1471 cache.remove(caddrs.host, caddrs);
1472 }
1473 } else {
1474 // we encountered 1st element that expires in future
1475 break;
1476 }
1477 }
1478
1479 // look-up or remove from cache
1480 Addresses addrs;
1481 if (useCache) {
1482 addrs = cache.get(host);
1483 } else {
1484 addrs = cache.remove(host);
1485 if (addrs != null) {
1486 if (addrs instanceof CachedAddresses) {
1487 // try removing from expirySet too if CachedAddresses
1488 expirySet.remove(addrs);
1489 }
1490 addrs = null;
1491 }
1492 }
1493
1494 if (addrs == null) {
1495 // create a NameServiceAddresses instance which will look up
1496 // the name service and install it within cache...
1497 Addresses oldAddrs = cache.putIfAbsent(
1498 host,
1499 addrs = new NameServiceAddresses(host, reqAddr)
1500 );
1501 if (oldAddrs != null) { // lost putIfAbsent race
1502 addrs = oldAddrs;
1503 }
1504 }
1505
1506 // ask Addresses to get an array of InetAddress(es) and clone it
1507 return addrs.get().clone();
1508 }
1509
1510 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1511 throws UnknownHostException
1512 {
1513 InetAddress[] addresses = null;
1514 UnknownHostException ex = null;
1515
1516 try {
1517 addresses = nameService.lookupAllHostAddr(host);
1518 } catch (UnknownHostException uhe) {
1519 if (host.equalsIgnoreCase("localhost")) {
1520 addresses = new InetAddress[] { impl.loopbackAddress() };
1521 }
1522 else {
1523 ex = uhe;
1524 }
1525 }
1526
1527 if (addresses == null) {
1528 throw ex == null ? new UnknownHostException(host) : ex;
1529 }
1530
1531 // More to do?
1532 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1533 // Find it?
1534 int i = 1;
1535 for (; i < addresses.length; i++) {
1536 if (addresses[i].equals(reqAddr)) {
1537 break;
1538 }
1539 }
1540 // Rotate
1541 if (i < addresses.length) {
1542 InetAddress tmp, tmp2 = reqAddr;
1543 for (int j = 0; j < i; j++) {
1544 tmp = addresses[j];
1545 addresses[j] = tmp2;
1546 tmp2 = tmp;
1547 }
1548 addresses[i] = tmp2;
1549 }
1550 }
1551
1552 return addresses;
1553 }
1554
1555 /**
1556 * Returns an {@code InetAddress} object given the raw IP address .
1557 * The argument is in network byte order: the highest order
1558 * byte of the address is in {@code getAddress()[0]}.
1559 *
1560 * <p> This method doesn't block, i.e. no reverse name service lookup
1561 * is performed.
1562 *
1563 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1564 * must be 16 bytes long
1565 *
1566 * @param addr the raw IP address in network byte order
1567 * @return an InetAddress object created from the raw IP address.
1568 * @throws UnknownHostException if IP address is of illegal length
1569 * @since 1.4
1570 */
1571 public static InetAddress getByAddress(byte[] addr)
1572 throws UnknownHostException {
1573 return getByAddress(null, addr);
1574 }
1575
1576 private static final class CachedLocalHost {
1577 final String host;
1578 final InetAddress addr;
1579 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1580
1581 CachedLocalHost(String host, InetAddress addr) {
1582 this.host = host;
1583 this.addr = addr;
1584 }
1585 }
1586
1587 private static volatile CachedLocalHost cachedLocalHost;
1588
1589 /**
1590 * Returns the address of the local host. This is achieved by retrieving
1591 * the name of the host from the system, then resolving that name into
1592 * an {@code InetAddress}.
1593 *
1594 * <P>Note: The resolved address may be cached for a short period of time.
1595 * </P>
1596 *
1597 * <p>If there is a security manager, its
1598 * {@code checkConnect} method is called
1599 * with the local host name and {@code -1}
1600 * as its arguments to see if the operation is allowed.
1601 * If the operation is not allowed, an InetAddress representing
1602 * the loopback address is returned.
1603 *
1604 * @return the address of the local host.
1605 *
1606 * @throws UnknownHostException if the local host name could not
1607 * be resolved into an address.
1608 *
1609 * @see SecurityManager#checkConnect
1610 * @see java.net.InetAddress#getByName(java.lang.String)
1611 */
1612 public static InetAddress getLocalHost() throws UnknownHostException {
1613
1614 SecurityManager security = System.getSecurityManager();
1615 try {
1616 // is cached data still valid?
1617 CachedLocalHost clh = cachedLocalHost;
1618 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1619 if (security != null) {
1620 security.checkConnect(clh.host, -1);
1621 }
1622 return clh.addr;
1623 }
1624
1625 String local = impl.getLocalHostName();
1626
1627 if (security != null) {
1628 security.checkConnect(local, -1);
1629 }
1630
1631 InetAddress localAddr;
1632 if (local.equals("localhost")) {
1633 // shortcut for "localhost" host name
1634 localAddr = impl.loopbackAddress();
1635 } else {
1636 // call getAllByName0 without security checks and
1637 // without using cached data
1638 try {
1639 localAddr = getAllByName0(local, null, false, false)[0];
1640 } catch (UnknownHostException uhe) {
1641 // Rethrow with a more informative error message.
1642 UnknownHostException uhe2 =
1643 new UnknownHostException(local + ": " +
1644 uhe.getMessage());
1645 uhe2.initCause(uhe);
1646 throw uhe2;
1647 }
1648 }
1649 cachedLocalHost = new CachedLocalHost(local, localAddr);
1650 return localAddr;
1651 } catch (java.lang.SecurityException e) {
1652 return impl.loopbackAddress();
1653 }
1654 }
1655
1656 /**
1657 * Perform class load-time initializations.
1658 */
1659 private static native void init();
1660
1661
1662 /*
1663 * Returns the InetAddress representing anyLocalAddress
1664 * (typically 0.0.0.0 or ::0)
1665 */
1666 static InetAddress anyLocalAddress() {
1667 return impl.anyLocalAddress();
1668 }
1669
1670 /*
1671 * Load and instantiate an underlying impl class
1672 */
1673 static InetAddressImpl loadImpl(String implName) {
1674 Object impl = null;
1675
1676 /*
1677 * Property "impl.prefix" will be prepended to the classname
1678 * of the implementation object we instantiate, to which we
1679 * delegate the real work (like native methods). This
1680 * property can vary across implementations of the java.
1681 * classes. The default is an empty String "".
1682 */
1683 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
1684 try {
1685 @SuppressWarnings("deprecation")
1686 Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
1687 impl = tmp;
1688 } catch (ClassNotFoundException e) {
1689 System.err.println("Class not found: java.net." + prefix +
1690 implName + ":\ncheck impl.prefix property " +
1691 "in your properties file.");
1692 } catch (InstantiationException e) {
1693 System.err.println("Could not instantiate: java.net." + prefix +
1694 implName + ":\ncheck impl.prefix property " +
1695 "in your properties file.");
1696 } catch (IllegalAccessException e) {
1697 System.err.println("Cannot access class: java.net." + prefix +
1698 implName + ":\ncheck impl.prefix property " +
1699 "in your properties file.");
1700 }
1701
1702 if (impl == null) {
1703 try {
1704 @SuppressWarnings("deprecation")
1705 Object tmp = Class.forName(implName).newInstance();
1706 impl = tmp;
1707 } catch (Exception e) {
1708 throw new Error("System property impl.prefix incorrect");
1709 }
1710 }
1711
1712 return (InetAddressImpl) impl;
1713 }
1714
1715 @java.io.Serial
1716 private void readObjectNoData () {
1717 if (getClass().getClassLoader() != null) {
1718 throw new SecurityException ("invalid address type");
1719 }
1720 }
1721
1722 private static final jdk.internal.misc.Unsafe UNSAFE
1723 = jdk.internal.misc.Unsafe.getUnsafe();
1724 private static final long FIELDS_OFFSET
1725 = UNSAFE.objectFieldOffset(InetAddress.class, "holder");
1726
1727 @java.io.Serial
1728 private void readObject (ObjectInputStream s) throws
1729 IOException, ClassNotFoundException {
1730 if (getClass().getClassLoader() != null) {
1731 throw new SecurityException ("invalid address type");
1732 }
1733 GetField gf = s.readFields();
1734 String host = (String)gf.get("hostName", null);
1735 int address = gf.get("address", 0);
1736 int family = gf.get("family", 0);
1737 if (family != IPv4 && family != IPv6) {
1738 throw new InvalidObjectException("invalid address family type: " + family);
1739 }
1740 InetAddressHolder h = new InetAddressHolder(host, address, family);
1741 UNSAFE.putReference(this, FIELDS_OFFSET, h);
1742 }
1743
1744 /* needed because the serializable fields no longer exist */
1745
1746 /**
1747 * @serialField hostName String
1748 * @serialField address int
1749 * @serialField family int
1750 */
1751 @java.io.Serial
1752 private static final ObjectStreamField[] serialPersistentFields = {
1753 new ObjectStreamField("hostName", String.class),
1754 new ObjectStreamField("address", int.class),
1755 new ObjectStreamField("family", int.class),
1756 };
1757
1758 @java.io.Serial
1759 private void writeObject (ObjectOutputStream s) throws
1760 IOException {
1761 if (getClass().getClassLoader() != null) {
1762 throw new SecurityException ("invalid address type");
1763 }
1764 PutField pf = s.putFields();
1765 pf.put("hostName", holder().getHostName());
1766 pf.put("address", holder().getAddress());
1767 pf.put("family", holder().getFamily());
1768 s.writeFields();
1769 }
1770 }
1771
1772 /*
1773 * Simple factory to create the impl
1774 */
1775 class InetAddressImplFactory {
1776
1777 static InetAddressImpl create() {
1778 return InetAddress.loadImpl(isIPv6Supported() ?
1779 "Inet6AddressImpl" : "Inet4AddressImpl");
1780 }
1781
1782 static native boolean isIPv6Supported();
1783 }