1 /*
2 * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.net;
27
28 import java.util.NavigableSet;
29 import java.util.ArrayList;
30 import java.util.Objects;
31 import java.util.Scanner;
32 import java.security.AccessController;
33 import java.io.File;
34 import java.io.FileNotFoundException;
35 import java.io.ObjectStreamException;
36 import java.io.ObjectStreamField;
37 import java.io.IOException;
38 import java.io.InvalidObjectException;
39 import java.io.ObjectInputStream;
40 import java.io.ObjectInputStream.GetField;
41 import java.io.ObjectOutputStream;
42 import java.io.ObjectOutputStream.PutField;
43 import java.lang.annotation.Native;
44 import java.util.concurrent.ConcurrentHashMap;
45 import java.util.concurrent.ConcurrentMap;
46 import java.util.concurrent.ConcurrentSkipListSet;
47 import java.util.concurrent.atomic.AtomicLong;
48 import java.util.Arrays;
49
50 import jdk.internal.access.JavaNetInetAddressAccess;
51 import jdk.internal.access.SharedSecrets;
52 import sun.security.action.*;
53 import sun.net.InetAddressCachePolicy;
54 import sun.net.util.IPAddressUtil;
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
200 class InetAddress implements java.io.Serializable {
201
202 @Native static final int PREFER_IPV4_VALUE = 0;
203 @Native static final int PREFER_IPV6_VALUE = 1;
204 @Native static final int PREFER_SYSTEM_VALUE = 2;
205
206 /**
207 * Specify the address family: Internet Protocol, Version 4
208 * @since 1.4
209 */
210 @Native static final int IPv4 = 1;
211
212 /**
213 * Specify the address family: Internet Protocol, Version 6
214 * @since 1.4
215 */
216 @Native static final int IPv6 = 2;
217
218 /* Specify address family preference */
219 static transient final int preferIPv6Address;
220
221 static class InetAddressHolder {
222 /**
223 * Reserve the original application specified hostname.
224 *
225 * The original hostname is useful for domain-based endpoint
226 * identification (see RFC 2818 and RFC 6125). If an address
227 * was created with a raw IP address, a reverse name lookup
228 * may introduce endpoint identification security issue via
229 * DNS forging.
230 *
231 * Oracle JSSE provider is using this original hostname, via
232 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
233 *
234 * Note: May define a new public method in the future if necessary.
235 */
236 String originalHostName;
237
238 InetAddressHolder() {}
239
240 InetAddressHolder(String hostName, int address, int family) {
241 this.originalHostName = hostName;
242 this.hostName = hostName;
243 this.address = address;
244 this.family = family;
245 }
246
247 void init(String hostName, int family) {
248 this.originalHostName = hostName;
249 this.hostName = hostName;
250 if (family != -1) {
251 this.family = family;
252 }
253 }
254
255 String hostName;
256
257 String getHostName() {
258 return hostName;
259 }
260
261 String getOriginalHostName() {
262 return originalHostName;
263 }
264
265 /**
266 * Holds a 32-bit IPv4 address.
267 */
268 int address;
269
270 int getAddress() {
271 return address;
272 }
273
274 /**
275 * Specifies the address family type, for instance, '1' for IPv4
276 * addresses, and '2' for IPv6 addresses.
277 */
278 int family;
279
280 int getFamily() {
281 return family;
282 }
283 }
284
285 /* Used to store the serializable fields of InetAddress */
286 final transient InetAddressHolder holder;
287
288 InetAddressHolder holder() {
289 return holder;
290 }
291
292 /* Used to store the name service provider */
293 private static transient NameService nameService;
294
295 /**
296 * Used to store the best available hostname.
297 * Lazily initialized via a data race; safe because Strings are immutable.
298 */
299 private transient String canonicalHostName = null;
300
301 /** use serialVersionUID from JDK 1.0.2 for interoperability */
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.access.SharedSecrets.getJavaLangAccess().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 );
335 init();
336 }
337
338 /**
339 * Constructor for the Socket.accept() method.
340 * This creates an empty InetAddress, which is filled in by
341 * the accept() method. This InetAddress, however, is not
342 * put in the address cache, since it is not created by name.
343 */
344 InetAddress() {
345 holder = new InetAddressHolder();
346 }
347
348 /**
349 * Replaces the de-serialized object with an Inet4Address object.
350 *
351 * @return the alternate object to the de-serialized object.
352 *
353 * @throws ObjectStreamException if a new object replacing this
354 * object could not be created
355 */
356 private Object readResolve() throws ObjectStreamException {
357 // will replace the deserialized 'this' object
358 return new Inet4Address(holder().getHostName(), holder().getAddress());
359 }
360
361 /**
362 * Utility routine to check if the InetAddress is an
363 * IP multicast address.
364 * @return a {@code boolean} indicating if the InetAddress is
365 * an IP multicast address
366 * @since 1.1
367 */
368 public boolean isMulticastAddress() {
369 return false;
370 }
371
372 /**
373 * Utility routine to check if the InetAddress is a wildcard address.
374 * @return a {@code boolean} indicating if the InetAddress is
375 * a wildcard address.
376 * @since 1.4
377 */
378 public boolean isAnyLocalAddress() {
379 return false;
380 }
381
382 /**
383 * Utility routine to check if the InetAddress is a loopback address.
384 *
385 * @return a {@code boolean} indicating if the InetAddress is
386 * a loopback address; or false otherwise.
387 * @since 1.4
388 */
389 public boolean isLoopbackAddress() {
390 return false;
391 }
392
393 /**
394 * Utility routine to check if the InetAddress is an link local address.
395 *
396 * @return a {@code boolean} indicating if the InetAddress is
397 * a link local address; or false if address is not a link local unicast address.
398 * @since 1.4
399 */
400 public boolean isLinkLocalAddress() {
401 return false;
402 }
403
404 /**
405 * Utility routine to check if the InetAddress is a site local address.
406 *
407 * @return a {@code boolean} indicating if the InetAddress is
408 * a site local address; or false if address is not a site local unicast address.
409 * @since 1.4
410 */
411 public boolean isSiteLocalAddress() {
412 return false;
413 }
414
415 /**
416 * Utility routine to check if the multicast address has global scope.
417 *
418 * @return a {@code boolean} indicating if the address has
419 * is a multicast address of global scope, false if it is not
420 * of global scope or it is not a multicast address
421 * @since 1.4
422 */
423 public boolean isMCGlobal() {
424 return false;
425 }
426
427 /**
428 * Utility routine to check if the multicast address has node scope.
429 *
430 * @return a {@code boolean} indicating if the address has
431 * is a multicast address of node-local scope, false if it is not
432 * of node-local scope or it is not a multicast address
433 * @since 1.4
434 */
435 public boolean isMCNodeLocal() {
436 return false;
437 }
438
439 /**
440 * Utility routine to check if the multicast address has link scope.
441 *
442 * @return a {@code boolean} indicating if the address has
443 * is a multicast address of link-local scope, false if it is not
444 * of link-local scope or it is not a multicast address
445 * @since 1.4
446 */
447 public boolean isMCLinkLocal() {
448 return false;
449 }
450
451 /**
452 * Utility routine to check if the multicast address has site scope.
453 *
454 * @return a {@code boolean} indicating if the address has
455 * is a multicast address of site-local scope, false if it is not
456 * of site-local scope or it is not a multicast address
457 * @since 1.4
458 */
459 public boolean isMCSiteLocal() {
460 return false;
461 }
462
463 /**
464 * Utility routine to check if the multicast address has organization scope.
465 *
466 * @return a {@code boolean} indicating if the address has
467 * is a multicast address of organization-local scope,
468 * false if it is not of organization-local scope
469 * or it is not a multicast address
470 * @since 1.4
471 */
472 public boolean isMCOrgLocal() {
473 return false;
474 }
475
476
477 /**
478 * Test whether that address is reachable. Best effort is made by the
479 * implementation to try to reach the host, but firewalls and server
480 * configuration may block requests resulting in a unreachable status
481 * while some specific ports may be accessible.
482 * A typical implementation will use ICMP ECHO REQUESTs if the
483 * privilege can be obtained, otherwise it will try to establish
484 * a TCP connection on port 7 (Echo) of the destination host.
485 * <p>
486 * The timeout value, in milliseconds, indicates the maximum amount of time
487 * the try should take. If the operation times out before getting an
488 * answer, the host is deemed unreachable. A negative value will result
489 * in an IllegalArgumentException being thrown.
490 *
491 * @param timeout the time, in milliseconds, before the call aborts
492 * @return a {@code boolean} indicating if the address is reachable.
493 * @throws IOException if a network error occurs
494 * @throws IllegalArgumentException if {@code timeout} is negative.
495 * @since 1.5
496 */
497 public boolean isReachable(int timeout) throws IOException {
498 return isReachable(null, 0 , timeout);
499 }
500
501 /**
502 * Test whether that address is reachable. Best effort is made by the
503 * implementation to try to reach the host, but firewalls and server
504 * configuration may block requests resulting in a unreachable status
505 * while some specific ports may be accessible.
506 * A typical implementation will use ICMP ECHO REQUESTs if the
507 * privilege can be obtained, otherwise it will try to establish
508 * a TCP connection on port 7 (Echo) of the destination host.
509 * <p>
510 * The {@code network interface} and {@code ttl} parameters
511 * let the caller specify which network interface the test will go through
512 * and the maximum number of hops the packets should go through.
513 * A negative value for the {@code ttl} will result in an
514 * IllegalArgumentException being thrown.
515 * <p>
516 * The timeout value, in milliseconds, indicates the maximum amount of time
517 * the try should take. If the operation times out before getting an
518 * answer, the host is deemed unreachable. A negative value will result
519 * in an IllegalArgumentException being thrown.
520 *
521 * @param netif the NetworkInterface through which the
522 * test will be done, or null for any interface
523 * @param ttl the maximum numbers of hops to try or 0 for the
524 * default
525 * @param timeout the time, in milliseconds, before the call aborts
526 * @throws IllegalArgumentException if either {@code timeout}
527 * or {@code ttl} are negative.
528 * @return a {@code boolean} indicating if the address is reachable.
529 * @throws IOException if a network error occurs
530 * @since 1.5
531 */
532 public boolean isReachable(NetworkInterface netif, int ttl,
533 int timeout) throws IOException {
534 if (ttl < 0)
535 throw new IllegalArgumentException("ttl can't be negative");
536 if (timeout < 0)
537 throw new IllegalArgumentException("timeout can't be negative");
538
539 return impl.isReachable(this, timeout, netif, ttl);
540 }
541
542 /**
543 * Gets the host name for this IP address.
544 *
545 * <p>If this InetAddress was created with a host name,
546 * this host name will be remembered and returned;
547 * otherwise, a reverse name lookup will be performed
548 * and the result will be returned based on the system
549 * configured name lookup service. If a lookup of the name service
550 * is required, call
551 * {@link #getCanonicalHostName() getCanonicalHostName}.
552 *
553 * <p>If there is a security manager, its
554 * {@code checkConnect} method is first called
555 * with the hostname and {@code -1}
556 * as its arguments to see if the operation is allowed.
557 * If the operation is not allowed, it will return
558 * the textual representation of the IP address.
559 *
560 * @return the host name for this IP address, or if the operation
561 * is not allowed by the security check, the textual
562 * representation of the IP address.
563 *
564 * @see InetAddress#getCanonicalHostName
565 * @see SecurityManager#checkConnect
566 */
567 public String getHostName() {
568 return getHostName(true);
569 }
570
571 /**
572 * Returns the hostname for this address.
573 * If the host is equal to null, then this address refers to any
574 * of the local machine's available network addresses.
575 * this is package private so SocketPermission can make calls into
576 * here without a security check.
577 *
578 * <p>If there is a security manager, this method first
579 * calls its {@code checkConnect} method
580 * with the hostname and {@code -1}
581 * as its arguments to see if the calling code is allowed to know
582 * the hostname for this IP address, i.e., to connect to the host.
583 * If the operation is not allowed, it will return
584 * the textual representation of the IP address.
585 *
586 * @return the host name for this IP address, or if the operation
587 * is not allowed by the security check, the textual
588 * representation of the IP address.
589 *
590 * @param check make security check if true
591 *
592 * @see SecurityManager#checkConnect
593 */
594 String getHostName(boolean check) {
595 if (holder().getHostName() == null) {
596 holder().hostName = InetAddress.getHostFromNameService(this, check);
597 }
598 return holder().getHostName();
599 }
600
601 /**
602 * Gets the fully qualified domain name for this IP address.
603 * Best effort method, meaning we may not be able to return
604 * the FQDN depending on the underlying system configuration.
605 *
606 * <p>If there is a security manager, this method first
607 * calls its {@code checkConnect} method
608 * with the hostname and {@code -1}
609 * as its arguments to see if the calling code is allowed to know
610 * the hostname for this IP address, i.e., to connect to the host.
611 * If the operation is not allowed, it will return
612 * the textual representation of the IP address.
613 *
614 * @return the fully qualified domain name for this IP address,
615 * or if the operation is not allowed by the security check,
616 * the textual representation of the IP address.
617 *
618 * @see SecurityManager#checkConnect
619 *
620 * @since 1.4
621 */
622 public String getCanonicalHostName() {
623 String value = canonicalHostName;
624 if (value == null)
625 canonicalHostName = value =
626 InetAddress.getHostFromNameService(this, true);
627 return value;
628 }
629
630 /**
631 * Returns the hostname for this address.
632 *
633 * <p>If there is a security manager, this method first
634 * calls its {@code checkConnect} method
635 * with the hostname and {@code -1}
636 * as its arguments to see if the calling code is allowed to know
637 * the hostname for this IP address, i.e., to connect to the host.
638 * If the operation is not allowed, it will return
639 * the textual representation of the IP address.
640 *
641 * @return the host name for this IP address, or if the operation
642 * is not allowed by the security check, the textual
643 * representation of the IP address.
644 *
645 * @param check make security check if true
646 *
647 * @see SecurityManager#checkConnect
648 */
649 private static String getHostFromNameService(InetAddress addr, boolean check) {
650 String host = null;
651 try {
652 // first lookup the hostname
653 host = nameService.getHostByAddr(addr.getAddress());
654
655 /* check to see if calling code is allowed to know
656 * the hostname for this IP address, ie, connect to the host
657 */
658 if (check) {
659 SecurityManager sec = System.getSecurityManager();
660 if (sec != null) {
661 sec.checkConnect(host, -1);
662 }
663 }
664
665 /* now get all the IP addresses for this hostname,
666 * and make sure one of them matches the original IP
667 * address. We do this to try and prevent spoofing.
668 */
669
670 InetAddress[] arr = InetAddress.getAllByName0(host, check);
671 boolean ok = false;
672
673 if(arr != null) {
674 for(int i = 0; !ok && i < arr.length; i++) {
675 ok = addr.equals(arr[i]);
676 }
677 }
678
679 //XXX: if it looks a spoof just return the address?
680 if (!ok) {
681 host = addr.getHostAddress();
682 return host;
683 }
684 } catch (SecurityException e) {
685 host = addr.getHostAddress();
686 } catch (UnknownHostException e) {
687 host = addr.getHostAddress();
688 // let next provider resolve the hostname
689 }
690 return host;
691 }
692
693 /**
694 * Returns the raw IP address of this {@code InetAddress}
695 * object. The result is in network byte order: the highest order
696 * byte of the address is in {@code getAddress()[0]}.
697 *
698 * @return the raw IP address of this object.
699 */
700 public byte[] getAddress() {
701 return null;
702 }
703
704 /**
705 * Returns the IP address string in textual presentation.
706 *
707 * @return the raw IP address in a string format.
708 * @since 1.0.2
709 */
710 public String getHostAddress() {
711 return null;
712 }
713
714 /**
715 * Returns a hashcode for this IP address.
716 *
717 * @return a hash code value for this IP address.
718 */
719 public int hashCode() {
720 return -1;
721 }
722
723 /**
724 * Compares this object against the specified object.
725 * The result is {@code true} if and only if the argument is
726 * not {@code null} and it represents the same IP address as
727 * this object.
728 * <p>
729 * Two instances of {@code InetAddress} represent the same IP
730 * address if the length of the byte arrays returned by
731 * {@code getAddress} is the same for both, and each of the
732 * array components is the same for the byte arrays.
733 *
734 * @param obj the object to compare against.
735 * @return {@code true} if the objects are the same;
736 * {@code false} otherwise.
737 * @see java.net.InetAddress#getAddress()
738 */
739 public boolean equals(Object obj) {
740 return false;
741 }
742
743 /**
744 * Converts this IP address to a {@code String}. The
745 * string returned is of the form: hostname / literal IP
746 * address.
747 *
748 * If the host name is unresolved, no reverse name service lookup
749 * is performed. The hostname part will be represented by an empty string.
750 *
751 * @return a string representation of this IP address.
752 */
753 public String toString() {
754 String hostName = holder().getHostName();
755 return Objects.toString(hostName, "")
756 + "/" + getHostAddress();
757 }
758
759 // mapping from host name to Addresses - either NameServiceAddresses (while
760 // still being looked-up by NameService(s)) or CachedAddresses when cached
761 private static final ConcurrentMap<String, Addresses> cache =
762 new ConcurrentHashMap<>();
763
764 // CachedAddresses that have to expire are kept ordered in this NavigableSet
765 // which is scanned on each access
766 private static final NavigableSet<CachedAddresses> expirySet =
767 new ConcurrentSkipListSet<>();
768
769 // common interface
770 private interface Addresses {
771 InetAddress[] get() throws UnknownHostException;
772 }
773
774 // a holder for cached addresses with required metadata
775 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
776 private static final AtomicLong seq = new AtomicLong();
777 final String host;
778 final InetAddress[] inetAddresses;
779 final long expiryTime; // time of expiry (in terms of System.nanoTime())
780 final long id = seq.incrementAndGet(); // each instance is unique
781
782 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
783 this.host = host;
784 this.inetAddresses = inetAddresses;
785 this.expiryTime = expiryTime;
786 }
787
788 @Override
789 public InetAddress[] get() throws UnknownHostException {
790 if (inetAddresses == null) {
791 throw new UnknownHostException(host);
792 }
793 return inetAddresses;
794 }
795
796 @Override
797 public int compareTo(CachedAddresses other) {
798 // natural order is expiry time -
799 // compare difference of expiry times rather than
800 // expiry times directly, to avoid possible overflow.
801 // (see System.nanoTime() recommendations...)
802 long diff = this.expiryTime - other.expiryTime;
803 if (diff < 0L) return -1;
804 if (diff > 0L) return 1;
805 // ties are broken using unique id
806 return Long.compare(this.id, other.id);
807 }
808 }
809
810 // a name service lookup based Addresses implementation which replaces itself
811 // in cache when the result is obtained
812 private static final class NameServiceAddresses implements Addresses {
813 private final String host;
814 private final InetAddress reqAddr;
815
816 NameServiceAddresses(String host, InetAddress reqAddr) {
817 this.host = host;
818 this.reqAddr = reqAddr;
819 }
820
821 @Override
822 public InetAddress[] get() throws UnknownHostException {
823 Addresses addresses;
824 // only one thread is doing lookup to name service
825 // for particular host at any time.
826 synchronized (this) {
827 // re-check that we are still us + re-install us if slot empty
828 addresses = cache.putIfAbsent(host, this);
829 if (addresses == null) {
830 // this can happen when we were replaced by CachedAddresses in
831 // some other thread, then CachedAddresses expired and were
832 // removed from cache while we were waiting for lock...
833 addresses = this;
834 }
835 // still us ?
836 if (addresses == this) {
837 // lookup name services
838 InetAddress[] inetAddresses;
839 UnknownHostException ex;
840 int cachePolicy;
841 try {
842 inetAddresses = getAddressesFromNameService(host, reqAddr);
843 ex = null;
844 cachePolicy = InetAddressCachePolicy.get();
845 } catch (UnknownHostException uhe) {
846 inetAddresses = null;
847 ex = uhe;
848 cachePolicy = InetAddressCachePolicy.getNegative();
849 }
850 // remove or replace us with cached addresses according to cachePolicy
851 if (cachePolicy == InetAddressCachePolicy.NEVER) {
852 cache.remove(host, this);
853 } else {
854 CachedAddresses cachedAddresses = new CachedAddresses(
855 host,
856 inetAddresses,
857 cachePolicy == InetAddressCachePolicy.FOREVER
858 ? 0L
859 // cachePolicy is in [s] - we need [ns]
860 : System.nanoTime() + 1000_000_000L * cachePolicy
861 );
862 if (cache.replace(host, this, cachedAddresses) &&
863 cachePolicy != InetAddressCachePolicy.FOREVER) {
864 // schedule expiry
865 expirySet.add(cachedAddresses);
866 }
867 }
868 if (inetAddresses == null) {
869 throw ex == null ? new UnknownHostException(host) : ex;
870 }
871 return inetAddresses;
872 }
873 // else addresses != this
874 }
875 // delegate to different addresses when we are already replaced
876 // but outside of synchronized block to avoid any chance of dead-locking
877 return addresses.get();
878 }
879 }
880
881 /**
882 * NameService provides host and address lookup service
883 *
884 * @since 9
885 */
886 private interface NameService {
887
888 /**
889 * Lookup a host mapping by name. Retrieve the IP addresses
890 * associated with a host
891 *
892 * @param host the specified hostname
893 * @return array of IP addresses for the requested host
894 * @throws UnknownHostException
895 * if no IP address for the {@code host} could be found
896 */
897 InetAddress[] lookupAllHostAddr(String host)
898 throws UnknownHostException;
899
900 /**
901 * Lookup the host corresponding to the IP address provided
902 *
903 * @param addr byte array representing an IP address
904 * @return {@code String} representing the host name mapping
905 * @throws UnknownHostException
906 * if no host found for the specified IP address
907 */
908 String getHostByAddr(byte[] addr) throws UnknownHostException;
909
910 }
911
912 /**
913 * The default NameService implementation, which delegates to the underlying
914 * OS network libraries to resolve host address mappings.
915 *
916 * @since 9
917 */
918 private static final class PlatformNameService implements NameService {
919
920 public InetAddress[] lookupAllHostAddr(String host)
921 throws UnknownHostException
922 {
923 return impl.lookupAllHostAddr(host);
924 }
925
926 public String getHostByAddr(byte[] addr)
927 throws UnknownHostException
928 {
929 return impl.getHostByAddr(addr);
930 }
931 }
932
933 /**
934 * The HostsFileNameService provides host address mapping
935 * by reading the entries in a hosts file, which is specified by
936 * {@code jdk.net.hosts.file} system property
937 *
938 * <p>The file format is that which corresponds with the /etc/hosts file
939 * IP Address host alias list.
940 *
941 * <p>When the file lookup is enabled it replaces the default NameService
942 * implementation
943 *
944 * @since 9
945 */
946 private static final class HostsFileNameService implements NameService {
947
948 private final String hostsFile;
949
950 public HostsFileNameService (String hostsFileName) {
951 this.hostsFile = hostsFileName;
952 }
953
954 private String addrToString(byte addr[]) {
955 String stringifiedAddress = null;
956
957 if (addr.length == Inet4Address.INADDRSZ) {
958 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
959 } else { // treat as an IPV6 jobby
960 byte[] newAddr
961 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
962 if (newAddr != null) {
963 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
964 } else {
965 stringifiedAddress = Inet6Address.numericToTextFormat(addr);
966 }
967 }
968 return stringifiedAddress;
969 }
970
971 /**
972 * Lookup the host name corresponding to the IP address provided.
973 * Search the configured host file a host name corresponding to
974 * the specified IP address.
975 *
976 * @param addr byte array representing an IP address
977 * @return {@code String} representing the host name mapping
978 * @throws UnknownHostException
979 * if no host found for the specified IP address
980 */
981 @Override
982 public String getHostByAddr(byte[] addr) throws UnknownHostException {
983 String hostEntry;
984 String host = null;
985
986 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
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 (FileNotFoundException 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 = null;
1030 InetAddress[] res = null;
1031 byte addr[] = new byte[4];
1032 ArrayList<InetAddress> inetAddresses = null;
1033
1034 // lookup the file and create a list InetAddress for the specified host
1035 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
1036 while (hostsFileScanner.hasNextLine()) {
1037 hostEntry = hostsFileScanner.nextLine();
1038 if (!hostEntry.startsWith("#")) {
1039 hostEntry = removeComments(hostEntry);
1040 if (hostEntry.contains(host)) {
1041 addrStr = extractHostAddr(hostEntry, host);
1042 if ((addrStr != null) && (!addrStr.isEmpty())) {
1043 addr = createAddressByteArray(addrStr);
1044 if (inetAddresses == null) {
1045 inetAddresses = new ArrayList<>(1);
1046 }
1047 if (addr != null) {
1048 inetAddresses.add(InetAddress.getByAddress(host, addr));
1049 }
1050 }
1051 }
1052 }
1053 }
1054 } catch (FileNotFoundException e) {
1055 throw new UnknownHostException("Unable to resolve host " + host
1056 + " as hosts file " + hostsFile + " not found ");
1057 }
1058
1059 if (inetAddresses != null) {
1060 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]);
1061 } else {
1062 throw new UnknownHostException("Unable to resolve host " + host
1063 + " in hosts file " + hostsFile);
1064 }
1065 return res;
1066 }
1067
1068 private String removeComments(String hostsEntry) {
1069 String filteredEntry = hostsEntry;
1070 int hashIndex;
1071
1072 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1073 filteredEntry = hostsEntry.substring(0, hashIndex);
1074 }
1075 return filteredEntry;
1076 }
1077
1078 private byte [] createAddressByteArray(String addrStr) {
1079 byte[] addrArray;
1080 // check if IPV4 address - most likely
1081 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr);
1082 if (addrArray == null) {
1083 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
1084 }
1085 return addrArray;
1086 }
1087
1088 /** host to ip address mapping */
1089 private String extractHostAddr(String hostEntry, String host) {
1090 String[] mapping = hostEntry.split("\\s+");
1091 String hostAddr = null;
1092
1093 if (mapping.length >= 2) {
1094 // look at the host aliases
1095 for (int i = 1; i < mapping.length; i++) {
1096 if (mapping[i].equalsIgnoreCase(host)) {
1097 hostAddr = mapping[0];
1098 }
1099 }
1100 }
1101 return hostAddr;
1102 }
1103 }
1104
1105 static final InetAddressImpl impl;
1106
1107 static {
1108 // create the impl
1109 impl = InetAddressImplFactory.create();
1110
1111 // create name service
1112 nameService = createNameService();
1113 }
1114
1115 /**
1116 * Create an instance of the NameService interface based on
1117 * the setting of the {@code jdk.net.hosts.file} system property.
1118 *
1119 * <p>The default NameService is the PlatformNameService, which typically
1120 * delegates name and address resolution calls to the underlying
1121 * OS network libraries.
1122 *
1123 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1124 * system property is set. If the specified file doesn't exist, the name or
1125 * address lookup will result in an UnknownHostException. Thus, non existent
1126 * hosts file is handled as if the file is empty.
1127 *
1128 * @return a NameService
1129 */
1130 private static NameService createNameService() {
1131
1132 String hostsFileName =
1133 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file");
1134 NameService theNameService;
1135 if (hostsFileName != null) {
1136 theNameService = new HostsFileNameService(hostsFileName);
1137 } else {
1138 theNameService = new PlatformNameService();
1139 }
1140 return theNameService;
1141 }
1142
1143 /**
1144 * Creates an InetAddress based on the provided host name and IP address.
1145 * No name service is checked for the validity of the address.
1146 *
1147 * <p> The host name can either be a machine name, such as
1148 * "{@code www.example.com}", or a textual representation of its IP
1149 * address.
1150 * <p> No validity checking is done on the host name either.
1151 *
1152 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1153 * will be returned; otherwise, an instance of Inet6Address
1154 * will be returned.
1155 *
1156 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1157 * must be 16 bytes long
1158 *
1159 * @param host the specified host
1160 * @param addr the raw IP address in network byte order
1161 * @return an InetAddress object created from the raw IP address.
1162 * @exception UnknownHostException if IP address is of illegal length
1163 * @since 1.4
1164 */
1165 public static InetAddress getByAddress(String host, byte[] addr)
1166 throws UnknownHostException {
1167 if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
1168 if (host.charAt(host.length()-1) == ']') {
1169 host = host.substring(1, host.length() -1);
1170 }
1171 }
1172 if (addr != null) {
1173 if (addr.length == Inet4Address.INADDRSZ) {
1174 return new Inet4Address(host, addr);
1175 } else if (addr.length == Inet6Address.INADDRSZ) {
1176 byte[] newAddr
1177 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1178 if (newAddr != null) {
1179 return new Inet4Address(host, newAddr);
1180 } else {
1181 return new Inet6Address(host, addr);
1182 }
1183 }
1184 }
1185 throw new UnknownHostException("addr is of illegal length");
1186 }
1187
1188
1189 /**
1190 * Determines the IP address of a host, given the host's name.
1191 *
1192 * <p> The host name can either be a machine name, such as
1193 * "{@code www.example.com}", or a textual representation of its
1194 * IP address. If a literal IP address is supplied, only the
1195 * validity of the address format is checked.
1196 *
1197 * <p> For {@code host} specified in literal IPv6 address,
1198 * either the form defined in RFC 2732 or the literal IPv6 address
1199 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1200 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1201 * scoped addresses.
1202 *
1203 * <p> If the host is {@code null} or {@code host.length()} is equal
1204 * to zero, then an {@code InetAddress} representing an address of the
1205 * loopback interface is returned.
1206 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1207 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1208 * section 2.5.3.
1209 *
1210 * <p> If there is a security manager, and {@code host} is not {@code null}
1211 * or {@code host.length() } is not equal to zero, the security manager's
1212 * {@code checkConnect} method is called with the hostname and {@code -1}
1213 * as its arguments to determine if the operation is allowed.
1214 *
1215 * @param host the specified host, or {@code null}.
1216 * @return an IP address for the given host name.
1217 * @exception UnknownHostException if no IP address for the
1218 * {@code host} could be found, or if a scope_id was specified
1219 * for a global IPv6 address.
1220 * @exception SecurityException if a security manager exists
1221 * and its checkConnect method doesn't allow the operation
1222 */
1223 public static InetAddress getByName(String host)
1224 throws UnknownHostException {
1225 return InetAddress.getAllByName(host)[0];
1226 }
1227
1228 // called from deployment cache manager
1229 private static InetAddress getByName(String host, InetAddress reqAddr)
1230 throws UnknownHostException {
1231 return InetAddress.getAllByName(host, reqAddr)[0];
1232 }
1233
1234 /**
1235 * Given the name of a host, returns an array of its IP addresses,
1236 * based on the configured name service on the system.
1237 *
1238 * <p> The host name can either be a machine name, such as
1239 * "{@code www.example.com}", or a textual representation of its IP
1240 * address. If a literal IP address is supplied, only the
1241 * validity of the address format is checked.
1242 *
1243 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1244 * either the form defined in RFC 2732 or the literal IPv6 address
1245 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1246 * also be qualified by appending a scoped zone identifier or scope_id.
1247 * The syntax and usage of scope_ids is described
1248 * <a href="Inet6Address.html#scoped">here</a>.
1249 *
1250 * <p> If the host is {@code null} or {@code host.length()} is equal
1251 * to zero, then an {@code InetAddress} representing an address of the
1252 * loopback interface is returned.
1253 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1254 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1255 * section 2.5.3. </p>
1256 *
1257 * <p> If there is a security manager, and {@code host} is not {@code null}
1258 * or {@code host.length() } is not equal to zero, the security manager's
1259 * {@code checkConnect} method is called with the hostname and {@code -1}
1260 * as its arguments to determine if the operation is allowed.
1261 *
1262 * @param host the name of the host, or {@code null}.
1263 * @return an array of all the IP addresses for a given host name.
1264 *
1265 * @exception UnknownHostException if no IP address for the
1266 * {@code host} could be found, or if a scope_id was specified
1267 * for a global IPv6 address.
1268 * @exception SecurityException if a security manager exists and its
1269 * {@code checkConnect} method doesn't allow the operation.
1270 *
1271 * @see SecurityManager#checkConnect
1272 */
1273 public static InetAddress[] getAllByName(String host)
1274 throws UnknownHostException {
1275 return getAllByName(host, null);
1276 }
1277
1278 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1279 throws UnknownHostException {
1280
1281 if (host == null || host.isEmpty()) {
1282 InetAddress[] ret = new InetAddress[1];
1283 ret[0] = impl.loopbackAddress();
1284 return ret;
1285 }
1286
1287 boolean ipv6Expected = false;
1288 if (host.charAt(0) == '[') {
1289 // This is supposed to be an IPv6 literal
1290 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1291 host = host.substring(1, host.length() -1);
1292 ipv6Expected = true;
1293 } else {
1294 // This was supposed to be a IPv6 address, but it's not!
1295 throw new UnknownHostException(host + ": invalid IPv6 address");
1296 }
1297 }
1298
1299 // if host is an IP address, we won't do further lookup
1300 if (Character.digit(host.charAt(0), 16) != -1
1301 || (host.charAt(0) == ':')) {
1302 byte[] addr = null;
1303 int numericZone = -1;
1304 String ifname = null;
1305 // see if it is IPv4 address
1306 addr = IPAddressUtil.textToNumericFormatV4(host);
1307 if (addr == null) {
1308 // This is supposed to be an IPv6 literal
1309 // Check if a numeric or string zone id is present
1310 int pos;
1311 if ((pos=host.indexOf ('%')) != -1) {
1312 numericZone = checkNumericZone (host);
1313 if (numericZone == -1) { /* remainder of string must be an ifname */
1314 ifname = host.substring (pos+1);
1315 }
1316 }
1317 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1318 throw new UnknownHostException(host + ": invalid IPv6 address");
1319 }
1320 } else if (ipv6Expected) {
1321 // Means an IPv4 literal between brackets!
1322 throw new UnknownHostException("["+host+"]");
1323 }
1324 InetAddress[] ret = new InetAddress[1];
1325 if(addr != null) {
1326 if (addr.length == Inet4Address.INADDRSZ) {
1327 ret[0] = new Inet4Address(null, addr);
1328 } else {
1329 if (ifname != null) {
1330 ret[0] = new Inet6Address(null, addr, ifname);
1331 } else {
1332 ret[0] = new Inet6Address(null, addr, numericZone);
1333 }
1334 }
1335 return ret;
1336 }
1337 } else if (ipv6Expected) {
1338 // We were expecting an IPv6 Literal, but got something else
1339 throw new UnknownHostException("["+host+"]");
1340 }
1341 return getAllByName0(host, reqAddr, true, true);
1342 }
1343
1344 /**
1345 * Returns the loopback address.
1346 * <p>
1347 * The InetAddress returned will represent the IPv4
1348 * loopback address, 127.0.0.1, or the IPv6 loopback
1349 * address, ::1. The IPv4 loopback address returned
1350 * is only one of many in the form 127.*.*.*
1351 *
1352 * @return the InetAddress loopback instance.
1353 * @since 1.7
1354 */
1355 public static InetAddress getLoopbackAddress() {
1356 return impl.loopbackAddress();
1357 }
1358
1359
1360 /**
1361 * check if the literal address string has %nn appended
1362 * returns -1 if not, or the numeric value otherwise.
1363 *
1364 * %nn may also be a string that represents the displayName of
1365 * a currently available NetworkInterface.
1366 */
1367 private static int checkNumericZone (String s) throws UnknownHostException {
1368 int percent = s.indexOf ('%');
1369 int slen = s.length();
1370 int digit, zone=0;
1371 if (percent == -1) {
1372 return -1;
1373 }
1374 for (int i=percent+1; i<slen; i++) {
1375 char c = s.charAt(i);
1376 if (c == ']') {
1377 if (i == percent+1) {
1378 /* empty per-cent field */
1379 return -1;
1380 }
1381 break;
1382 }
1383 if ((digit = Character.digit (c, 10)) < 0) {
1384 return -1;
1385 }
1386 zone = (zone * 10) + digit;
1387 }
1388 return zone;
1389 }
1390
1391 private static InetAddress[] getAllByName0 (String host)
1392 throws UnknownHostException
1393 {
1394 return getAllByName0(host, true);
1395 }
1396
1397 /**
1398 * package private so SocketPermission can call it
1399 */
1400 static InetAddress[] getAllByName0 (String host, boolean check)
1401 throws UnknownHostException {
1402 return getAllByName0 (host, null, check, true);
1403 }
1404
1405 /**
1406 * Designated lookup method.
1407 *
1408 * @param host host name to look up
1409 * @param reqAddr requested address to be the 1st in returned array
1410 * @param check perform security check
1411 * @param useCache use cached value if not expired else always
1412 * perform name service lookup (and cache the result)
1413 * @return array of InetAddress(es)
1414 * @throws UnknownHostException if host name is not found
1415 */
1416 private static InetAddress[] getAllByName0(String host,
1417 InetAddress reqAddr,
1418 boolean check,
1419 boolean useCache)
1420 throws UnknownHostException {
1421
1422 /* If it gets here it is presumed to be a hostname */
1423
1424 /* make sure the connection to the host is allowed, before we
1425 * give out a hostname
1426 */
1427 if (check) {
1428 SecurityManager security = System.getSecurityManager();
1429 if (security != null) {
1430 security.checkConnect(host, -1);
1431 }
1432 }
1433
1434 // remove expired addresses from cache - expirySet keeps them ordered
1435 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1436 long now = System.nanoTime();
1437 for (CachedAddresses caddrs : expirySet) {
1438 // compare difference of time instants rather than
1439 // time instants directly, to avoid possible overflow.
1440 // (see System.nanoTime() recommendations...)
1441 if ((caddrs.expiryTime - now) < 0L) {
1442 // ConcurrentSkipListSet uses weakly consistent iterator,
1443 // so removing while iterating is OK...
1444 if (expirySet.remove(caddrs)) {
1445 // ... remove from cache
1446 cache.remove(caddrs.host, caddrs);
1447 }
1448 } else {
1449 // we encountered 1st element that expires in future
1450 break;
1451 }
1452 }
1453
1454 // look-up or remove from cache
1455 Addresses addrs;
1456 if (useCache) {
1457 addrs = cache.get(host);
1458 } else {
1459 addrs = cache.remove(host);
1460 if (addrs != null) {
1461 if (addrs instanceof CachedAddresses) {
1462 // try removing from expirySet too if CachedAddresses
1463 expirySet.remove(addrs);
1464 }
1465 addrs = null;
1466 }
1467 }
1468
1469 if (addrs == null) {
1470 // create a NameServiceAddresses instance which will look up
1471 // the name service and install it within cache...
1472 Addresses oldAddrs = cache.putIfAbsent(
1473 host,
1474 addrs = new NameServiceAddresses(host, reqAddr)
1475 );
1476 if (oldAddrs != null) { // lost putIfAbsent race
1477 addrs = oldAddrs;
1478 }
1479 }
1480
1481 // ask Addresses to get an array of InetAddress(es) and clone it
1482 return addrs.get().clone();
1483 }
1484
1485 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1486 throws UnknownHostException
1487 {
1488 InetAddress[] addresses = null;
1489 UnknownHostException ex = null;
1490
1491 try {
1492 addresses = nameService.lookupAllHostAddr(host);
1493 } catch (UnknownHostException uhe) {
1494 if (host.equalsIgnoreCase("localhost")) {
1495 addresses = new InetAddress[] { impl.loopbackAddress() };
1496 }
1497 else {
1498 ex = uhe;
1499 }
1500 }
1501
1502 if (addresses == null) {
1503 throw ex == null ? new UnknownHostException(host) : ex;
1504 }
1505
1506 // More to do?
1507 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1508 // Find it?
1509 int i = 1;
1510 for (; i < addresses.length; i++) {
1511 if (addresses[i].equals(reqAddr)) {
1512 break;
1513 }
1514 }
1515 // Rotate
1516 if (i < addresses.length) {
1517 InetAddress tmp, tmp2 = reqAddr;
1518 for (int j = 0; j < i; j++) {
1519 tmp = addresses[j];
1520 addresses[j] = tmp2;
1521 tmp2 = tmp;
1522 }
1523 addresses[i] = tmp2;
1524 }
1525 }
1526
1527 return addresses;
1528 }
1529
1530 /**
1531 * Returns an {@code InetAddress} object given the raw IP address .
1532 * The argument is in network byte order: the highest order
1533 * byte of the address is in {@code getAddress()[0]}.
1534 *
1535 * <p> This method doesn't block, i.e. no reverse name service lookup
1536 * is performed.
1537 *
1538 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1539 * must be 16 bytes long
1540 *
1541 * @param addr the raw IP address in network byte order
1542 * @return an InetAddress object created from the raw IP address.
1543 * @exception UnknownHostException if IP address is of illegal length
1544 * @since 1.4
1545 */
1546 public static InetAddress getByAddress(byte[] addr)
1547 throws UnknownHostException {
1548 return getByAddress(null, addr);
1549 }
1550
1551 private static final class CachedLocalHost {
1552 final String host;
1553 final InetAddress addr;
1554 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1555
1556 CachedLocalHost(String host, InetAddress addr) {
1557 this.host = host;
1558 this.addr = addr;
1559 }
1560 }
1561
1562 private static volatile CachedLocalHost cachedLocalHost;
1563
1564 /**
1565 * Returns the address of the local host. This is achieved by retrieving
1566 * the name of the host from the system, then resolving that name into
1567 * an {@code InetAddress}.
1568 *
1569 * <P>Note: The resolved address may be cached for a short period of time.
1570 * </P>
1571 *
1572 * <p>If there is a security manager, its
1573 * {@code checkConnect} method is called
1574 * with the local host name and {@code -1}
1575 * as its arguments to see if the operation is allowed.
1576 * If the operation is not allowed, an InetAddress representing
1577 * the loopback address is returned.
1578 *
1579 * @return the address of the local host.
1580 *
1581 * @exception UnknownHostException if the local host name could not
1582 * be resolved into an address.
1583 *
1584 * @see SecurityManager#checkConnect
1585 * @see java.net.InetAddress#getByName(java.lang.String)
1586 */
1587 public static InetAddress getLocalHost() throws UnknownHostException {
1588
1589 SecurityManager security = System.getSecurityManager();
1590 try {
1591 // is cached data still valid?
1592 CachedLocalHost clh = cachedLocalHost;
1593 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1594 if (security != null) {
1595 security.checkConnect(clh.host, -1);
1596 }
1597 return clh.addr;
1598 }
1599
1600 String local = impl.getLocalHostName();
1601
1602 if (security != null) {
1603 security.checkConnect(local, -1);
1604 }
1605
1606 InetAddress localAddr;
1607 if (local.equals("localhost")) {
1608 // shortcut for "localhost" host name
1609 localAddr = impl.loopbackAddress();
1610 } else {
1611 // call getAllByName0 without security checks and
1612 // without using cached data
1613 try {
1614 localAddr = getAllByName0(local, null, false, false)[0];
1615 } catch (UnknownHostException uhe) {
1616 // Rethrow with a more informative error message.
1617 UnknownHostException uhe2 =
1618 new UnknownHostException(local + ": " +
1619 uhe.getMessage());
1620 uhe2.initCause(uhe);
1621 throw uhe2;
1622 }
1623 }
1624 cachedLocalHost = new CachedLocalHost(local, localAddr);
1625 return localAddr;
1626 } catch (java.lang.SecurityException e) {
1627 return impl.loopbackAddress();
1628 }
1629 }
1630
1631 /**
1632 * Perform class load-time initializations.
1633 */
1634 private static native void init();
1635
1636
1637 /*
1638 * Returns the InetAddress representing anyLocalAddress
1639 * (typically 0.0.0.0 or ::0)
1640 */
1641 static InetAddress anyLocalAddress() {
1642 return impl.anyLocalAddress();
1643 }
1644
1645 /*
1646 * Load and instantiate an underlying impl class
1647 */
1648 static InetAddressImpl loadImpl(String implName) {
1649 Object impl = null;
1650
1651 /*
1652 * Property "impl.prefix" will be prepended to the classname
1653 * of the implementation object we instantiate, to which we
1654 * delegate the real work (like native methods). This
1655 * property can vary across implementations of the java.
1656 * classes. The default is an empty String "".
1657 */
1658 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
1659 try {
1660 @SuppressWarnings("deprecation")
1661 Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
1662 impl = tmp;
1663 } catch (ClassNotFoundException e) {
1664 System.err.println("Class not found: java.net." + prefix +
1665 implName + ":\ncheck impl.prefix property " +
1666 "in your properties file.");
1667 } catch (InstantiationException e) {
1668 System.err.println("Could not instantiate: java.net." + prefix +
1669 implName + ":\ncheck impl.prefix property " +
1670 "in your properties file.");
1671 } catch (IllegalAccessException e) {
1672 System.err.println("Cannot access class: java.net." + prefix +
1673 implName + ":\ncheck impl.prefix property " +
1674 "in your properties file.");
1675 }
1676
1677 if (impl == null) {
1678 try {
1679 @SuppressWarnings("deprecation")
1680 Object tmp = Class.forName(implName).newInstance();
1681 impl = tmp;
1682 } catch (Exception e) {
1683 throw new Error("System property impl.prefix incorrect");
1684 }
1685 }
1686
1687 return (InetAddressImpl) impl;
1688 }
1689
1690 private void readObjectNoData () {
1691 if (getClass().getClassLoader() != null) {
1692 throw new SecurityException ("invalid address type");
1693 }
1694 }
1695
1696 private static final jdk.internal.misc.Unsafe UNSAFE
1697 = jdk.internal.misc.Unsafe.getUnsafe();
1698 private static final long FIELDS_OFFSET
1699 = UNSAFE.objectFieldOffset(InetAddress.class, "holder");
1700
1701 private void readObject (ObjectInputStream s) throws
1702 IOException, ClassNotFoundException {
1703 if (getClass().getClassLoader() != null) {
1704 throw new SecurityException ("invalid address type");
1705 }
1706 GetField gf = s.readFields();
1707 String host = (String)gf.get("hostName", null);
1708 int address = gf.get("address", 0);
1709 int family = gf.get("family", 0);
1710 if (family != IPv4 && family != IPv6) {
1711 throw new InvalidObjectException("invalid address family type: " + family);
1712 }
1713 InetAddressHolder h = new InetAddressHolder(host, address, family);
1714 UNSAFE.putReference(this, FIELDS_OFFSET, h);
1715 }
1716
1717 /* needed because the serializable fields no longer exist */
1718
1719 /**
1720 * @serialField hostName String
1721 * @serialField address int
1722 * @serialField family int
1723 */
1724 private static final ObjectStreamField[] serialPersistentFields = {
1725 new ObjectStreamField("hostName", String.class),
1726 new ObjectStreamField("address", int.class),
1727 new ObjectStreamField("family", int.class),
1728 };
1729
1730 private void writeObject (ObjectOutputStream s) throws
1731 IOException {
1732 if (getClass().getClassLoader() != null) {
1733 throw new SecurityException ("invalid address type");
1734 }
1735 PutField pf = s.putFields();
1736 pf.put("hostName", holder().getHostName());
1737 pf.put("address", holder().getAddress());
1738 pf.put("family", holder().getFamily());
1739 s.writeFields();
1740 }
1741 }
1742
1743 /*
1744 * Simple factory to create the impl
1745 */
1746 class InetAddressImplFactory {
1747
1748 static InetAddressImpl create() {
1749 return InetAddress.loadImpl(isIPv6Supported() ?
1750 "Inet6AddressImpl" : "Inet4AddressImpl");
1751 }
1752
1753 static native boolean isIPv6Supported();
1754 }