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