1 /*
2 * Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.net;
27
28 import java.util.NavigableSet;
29 import java.util.ArrayList;
30 import java.util.Objects;
31 import java.util.Scanner;
32 import java.security.AccessController;
33 import java.io.File;
34 import java.io.FileNotFoundException;
35 import java.io.ObjectStreamException;
36 import java.io.ObjectStreamField;
37 import java.io.IOException;
38 import java.io.ObjectInputStream;
39 import java.io.ObjectInputStream.GetField;
40 import java.io.ObjectOutputStream;
41 import java.io.ObjectOutputStream.PutField;
42 import java.lang.annotation.Native;
43 import java.util.concurrent.ConcurrentHashMap;
44 import java.util.concurrent.ConcurrentMap;
45 import java.util.concurrent.ConcurrentSkipListSet;
46 import java.util.concurrent.atomic.AtomicLong;
47
48 import jdk.internal.misc.JavaNetInetAddressAccess;
49 import jdk.internal.misc.SharedSecrets;
50 import sun.security.action.*;
51 import sun.net.InetAddressCachePolicy;
52 import sun.net.util.IPAddressUtil;
53
54 /**
55 * This class represents an Internet Protocol (IP) address.
56 *
57 * <p> An IP address is either a 32-bit or 128-bit unsigned number
58 * used by IP, a lower-level protocol on which protocols like UDP and
59 * TCP are built. The IP address architecture is defined by <a
60 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790:
61 * Assigned Numbers</i></a>, <a
62 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918:
63 * Address Allocation for Private Internets</i></a>, <a
64 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365:
65 * Administratively Scoped IP Multicast</i></a>, and <a
66 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP
67 * Version 6 Addressing Architecture</i></a>. An instance of an
68 * InetAddress consists of an IP address and possibly its
69 * corresponding host name (depending on whether it is constructed
70 * with a host name or whether it has already done reverse host name
71 * resolution).
72 *
73 * <h3> Address types </h3>
74 *
75 * <table class="striped" style="margin-left:2em">
76 * <caption style="display:none">Description of unicast and multicast address types</caption>
77 * <thead>
78 * <tr><th scope="col">Address Type</th><th scope="col">Description</th></tr>
79 * </thead>
80 * <tbody>
81 * <tr><th scope="row" style="vertical-align:top">unicast</th>
82 * <td>An identifier for a single interface. A packet sent to
83 * a unicast address is delivered to the interface identified by
84 * that address.
85 *
86 * <p> The Unspecified Address -- Also called anylocal or wildcard
87 * address. It must never be assigned to any node. It indicates the
88 * absence of an address. One example of its use is as the target of
89 * bind, which allows a server to accept a client connection on any
90 * interface, in case the server host has multiple interfaces.
91 *
92 * <p> The <i>unspecified</i> address must not be used as
93 * the destination address of an IP packet.
94 *
95 * <p> The <i>Loopback</i> Addresses -- This is the address
96 * assigned to the loopback interface. Anything sent to this
97 * IP address loops around and becomes IP input on the local
98 * host. This address is often used when testing a
99 * client.</td></tr>
100 * <tr><th scope="row" style="vertical-align:top">multicast</th>
101 * <td>An identifier for a set of interfaces (typically belonging
102 * to different nodes). A packet sent to a multicast address is
103 * delivered to all interfaces identified by that address.</td></tr>
104 * </tbody>
105 * </table>
106 *
107 * <h4> IP address scope </h4>
108 *
109 * <p> <i>Link-local</i> addresses are designed to be used for addressing
110 * on a single link for purposes such as auto-address configuration,
111 * neighbor discovery, or when no routers are present.
112 *
113 * <p> <i>Site-local</i> addresses are designed to be used for addressing
114 * inside of a site without the need for a global prefix.
115 *
116 * <p> <i>Global</i> addresses are unique across the internet.
117 *
118 * <h4> Textual representation of IP addresses </h4>
119 *
120 * The textual representation of an IP address is address family specific.
121 *
122 * <p>
123 *
124 * For IPv4 address format, please refer to <A
125 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6
126 * address format, please refer to <A
127 * HREF="Inet6Address.html#format">Inet6Address#format</A>.
128 *
129 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of
130 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P>
131 *
132 * <h4> Host Name Resolution </h4>
133 *
134 * Host name-to-IP address <i>resolution</i> is accomplished through
135 * the use of a combination of local machine configuration information
136 * and network naming services such as the Domain Name System (DNS)
137 * and Network Information Service(NIS). The particular naming
138 * services(s) being used is by default the local machine configured
139 * one. For any host name, its corresponding IP address is returned.
140 *
141 * <p> <i>Reverse name resolution</i> means that for any IP address,
142 * the host associated with the IP address is returned.
143 *
144 * <p> The InetAddress class provides methods to resolve host names to
145 * their IP addresses and vice versa.
146 *
147 * <h4> InetAddress Caching </h4>
148 *
149 * The InetAddress class has a cache to store successful as well as
150 * unsuccessful host name resolutions.
151 *
152 * <p> By default, when a security manager is installed, in order to
153 * protect against DNS spoofing attacks,
154 * the result of positive host name resolutions are
155 * cached forever. When a security manager is not installed, the default
156 * behavior is to cache entries for a finite (implementation dependent)
157 * period of time. The result of unsuccessful host
158 * name resolution is cached for a very short period of time (10
159 * seconds) to improve performance.
160 *
161 * <p> If the default behavior is not desired, then a Java security property
162 * can be set to a different Time-to-live (TTL) value for positive
163 * caching. Likewise, a system admin can configure a different
164 * negative caching TTL value when needed.
165 *
166 * <p> Two Java security properties control the TTL values used for
167 * positive and negative host name resolution caching:
168 *
169 * <dl style="margin-left:2em">
170 * <dt><b>networkaddress.cache.ttl</b></dt>
171 * <dd>Indicates the caching policy for successful name lookups from
172 * the name service. The value is specified as an integer to indicate
173 * the number of seconds to cache the successful lookup. The default
174 * setting is to cache for an implementation specific period of time.
175 * <p>
176 * A value of -1 indicates "cache forever".
177 * </dd>
178 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt>
179 * <dd>Indicates the caching policy for un-successful name lookups
180 * from the name service. The value is specified as an integer to
181 * indicate the number of seconds to cache the failure for
182 * un-successful lookups.
183 * <p>
184 * A value of 0 indicates "never cache".
185 * A value of -1 indicates "cache forever".
186 * </dd>
187 * </dl>
188 *
189 * @author Chris Warth
190 * @see java.net.InetAddress#getByAddress(byte[])
191 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
192 * @see java.net.InetAddress#getAllByName(java.lang.String)
193 * @see java.net.InetAddress#getByName(java.lang.String)
194 * @see java.net.InetAddress#getLocalHost()
195 * @since 1.0
196 */
197 public
198 class InetAddress implements java.io.Serializable {
199
200 @Native static final int PREFER_IPV4_VALUE = 0;
201 @Native static final int PREFER_IPV6_VALUE = 1;
202 @Native static final int PREFER_SYSTEM_VALUE = 2;
203
204 /**
205 * Specify the address family: Internet Protocol, Version 4
206 * @since 1.4
207 */
208 @Native static final int IPv4 = 1;
209
210 /**
211 * Specify the address family: Internet Protocol, Version 6
212 * @since 1.4
213 */
214 @Native static final int IPv6 = 2;
215
216 /* Specify address family preference */
217 static transient final int preferIPv6Address;
218
219 static class InetAddressHolder {
220 /**
221 * Reserve the original application specified hostname.
222 *
223 * The original hostname is useful for domain-based endpoint
224 * identification (see RFC 2818 and RFC 6125). If an address
225 * was created with a raw IP address, a reverse name lookup
226 * may introduce endpoint identification security issue via
227 * DNS forging.
228 *
229 * Oracle JSSE provider is using this original hostname, via
230 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
231 *
232 * Note: May define a new public method in the future if necessary.
233 */
234 String originalHostName;
235
236 InetAddressHolder() {}
237
238 InetAddressHolder(String hostName, int address, int family) {
239 this.originalHostName = hostName;
240 this.hostName = hostName;
241 this.address = address;
242 this.family = family;
243 }
244
245 void init(String hostName, int family) {
246 this.originalHostName = hostName;
247 this.hostName = hostName;
248 if (family != -1) {
249 this.family = family;
250 }
251 }
252
253 String hostName;
254
255 String getHostName() {
256 return hostName;
257 }
258
259 String getOriginalHostName() {
260 return originalHostName;
261 }
262
263 /**
264 * Holds a 32-bit IPv4 address.
265 */
266 int address;
267
268 int getAddress() {
269 return address;
270 }
271
272 /**
273 * Specifies the address family type, for instance, '1' for IPv4
274 * addresses, and '2' for IPv6 addresses.
275 */
276 int family;
277
278 int getFamily() {
279 return family;
280 }
281 }
282
283 /* Used to store the serializable fields of InetAddress */
284 final transient InetAddressHolder holder;
285
286 InetAddressHolder holder() {
287 return holder;
288 }
289
290 /* Used to store the name service provider */
291 private static transient NameService nameService = null;
292
293 /**
294 * Used to store the best available hostname.
295 * Lazily initialized via a data race; safe because Strings are immutable.
296 */
297 private transient String canonicalHostName = null;
298
299 /** use serialVersionUID from JDK 1.0.2 for interoperability */
300 private static final long serialVersionUID = 3286316764910316507L;
301
302 /*
303 * Load net library into runtime, and perform initializations.
304 */
305 static {
306 String str = java.security.AccessController.doPrivileged(
307 new GetPropertyAction("java.net.preferIPv6Addresses"));
308 if (str == null) {
309 preferIPv6Address = PREFER_IPV4_VALUE;
310 } else if (str.equalsIgnoreCase("true")) {
311 preferIPv6Address = PREFER_IPV6_VALUE;
312 } else if (str.equalsIgnoreCase("false")) {
313 preferIPv6Address = PREFER_IPV4_VALUE;
314 } else if (str.equalsIgnoreCase("system")) {
315 preferIPv6Address = PREFER_SYSTEM_VALUE;
316 } else {
317 preferIPv6Address = PREFER_IPV4_VALUE;
318 }
319 AccessController.doPrivileged(
320 new java.security.PrivilegedAction<>() {
321 public Void run() {
322 System.loadLibrary("net");
323 return null;
324 }
325 });
326 SharedSecrets.setJavaNetInetAddressAccess(
327 new JavaNetInetAddressAccess() {
328 public String getOriginalHostName(InetAddress ia) {
329 return ia.holder.getOriginalHostName();
330 }
331
332 public InetAddress getByName(String hostName,
333 InetAddress hostAddress)
334 throws UnknownHostException
335 {
336 return InetAddress.getByName(hostName, hostAddress);
337 }
338 }
339 );
340 init();
341 }
342
343 /**
344 * Constructor for the Socket.accept() method.
345 * This creates an empty InetAddress, which is filled in by
346 * the accept() method. This InetAddress, however, is not
347 * put in the address cache, since it is not created by name.
348 */
349 InetAddress() {
350 holder = new InetAddressHolder();
351 }
352
353 /**
354 * Replaces the de-serialized object with an Inet4Address object.
355 *
356 * @return the alternate object to the de-serialized object.
357 *
358 * @throws ObjectStreamException if a new object replacing this
359 * object could not be created
360 */
361 private Object readResolve() throws ObjectStreamException {
362 // will replace the deserialized 'this' object
363 return new Inet4Address(holder().getHostName(), holder().getAddress());
364 }
365
366 /**
367 * Utility routine to check if the InetAddress is an
368 * IP multicast address.
369 * @return a {@code boolean} indicating if the InetAddress is
370 * an IP multicast address
371 * @since 1.1
372 */
373 public boolean isMulticastAddress() {
374 return false;
375 }
376
377 /**
378 * Utility routine to check if the InetAddress is a wildcard address.
379 * @return a {@code boolean} indicating if the Inetaddress is
380 * a wildcard address.
381 * @since 1.4
382 */
383 public boolean isAnyLocalAddress() {
384 return false;
385 }
386
387 /**
388 * Utility routine to check if the InetAddress is a loopback address.
389 *
390 * @return a {@code boolean} indicating if the InetAddress is
391 * a loopback address; or false otherwise.
392 * @since 1.4
393 */
394 public boolean isLoopbackAddress() {
395 return false;
396 }
397
398 /**
399 * Utility routine to check if the InetAddress is an link local address.
400 *
401 * @return a {@code boolean} indicating if the InetAddress is
402 * a link local address; or false if address is not a link local unicast address.
403 * @since 1.4
404 */
405 public boolean isLinkLocalAddress() {
406 return false;
407 }
408
409 /**
410 * Utility routine to check if the InetAddress is a site local address.
411 *
412 * @return a {@code boolean} indicating if the InetAddress is
413 * a site local address; or false if address is not a site local unicast address.
414 * @since 1.4
415 */
416 public boolean isSiteLocalAddress() {
417 return false;
418 }
419
420 /**
421 * Utility routine to check if the multicast address has global scope.
422 *
423 * @return a {@code boolean} indicating if the address has
424 * is a multicast address of global scope, false if it is not
425 * of global scope or it is not a multicast address
426 * @since 1.4
427 */
428 public boolean isMCGlobal() {
429 return false;
430 }
431
432 /**
433 * Utility routine to check if the multicast address has node scope.
434 *
435 * @return a {@code boolean} indicating if the address has
436 * is a multicast address of node-local scope, false if it is not
437 * of node-local scope or it is not a multicast address
438 * @since 1.4
439 */
440 public boolean isMCNodeLocal() {
441 return false;
442 }
443
444 /**
445 * Utility routine to check if the multicast address has link scope.
446 *
447 * @return a {@code boolean} indicating if the address has
448 * is a multicast address of link-local scope, false if it is not
449 * of link-local scope or it is not a multicast address
450 * @since 1.4
451 */
452 public boolean isMCLinkLocal() {
453 return false;
454 }
455
456 /**
457 * Utility routine to check if the multicast address has site scope.
458 *
459 * @return a {@code boolean} indicating if the address has
460 * is a multicast address of site-local scope, false if it is not
461 * of site-local scope or it is not a multicast address
462 * @since 1.4
463 */
464 public boolean isMCSiteLocal() {
465 return false;
466 }
467
468 /**
469 * Utility routine to check if the multicast address has organization scope.
470 *
471 * @return a {@code boolean} indicating if the address has
472 * is a multicast address of organization-local scope,
473 * false if it is not of organization-local scope
474 * or it is not a multicast address
475 * @since 1.4
476 */
477 public boolean isMCOrgLocal() {
478 return false;
479 }
480
481
482 /**
483 * Test whether that address is reachable. Best effort is made by the
484 * implementation to try to reach the host, but firewalls and server
485 * configuration may block requests resulting in a unreachable status
486 * while some specific ports may be accessible.
487 * A typical implementation will use ICMP ECHO REQUESTs if the
488 * privilege can be obtained, otherwise it will try to establish
489 * a TCP connection on port 7 (Echo) of the destination host.
490 * <p>
491 * The timeout value, in milliseconds, indicates the maximum amount of time
492 * the try should take. If the operation times out before getting an
493 * answer, the host is deemed unreachable. A negative value will result
494 * in an IllegalArgumentException being thrown.
495 *
496 * @param timeout the time, in milliseconds, before the call aborts
497 * @return a {@code boolean} indicating if the address is reachable.
498 * @throws IOException if a network error occurs
499 * @throws IllegalArgumentException if {@code timeout} is negative.
500 * @since 1.5
501 */
502 public boolean isReachable(int timeout) throws IOException {
503 return isReachable(null, 0 , timeout);
504 }
505
506 /**
507 * Test whether that address is reachable. Best effort is made by the
508 * implementation to try to reach the host, but firewalls and server
509 * configuration may block requests resulting in a unreachable status
510 * while some specific ports may be accessible.
511 * A typical implementation will use ICMP ECHO REQUESTs if the
512 * privilege can be obtained, otherwise it will try to establish
513 * a TCP connection on port 7 (Echo) of the destination host.
514 * <p>
515 * The {@code network interface} and {@code ttl} parameters
516 * let the caller specify which network interface the test will go through
517 * and the maximum number of hops the packets should go through.
518 * A negative value for the {@code ttl} will result in an
519 * IllegalArgumentException being thrown.
520 * <p>
521 * The timeout value, in milliseconds, indicates the maximum amount of time
522 * the try should take. If the operation times out before getting an
523 * answer, the host is deemed unreachable. A negative value will result
524 * in an IllegalArgumentException being thrown.
525 *
526 * @param netif the NetworkInterface through which the
527 * test will be done, or null for any interface
528 * @param ttl the maximum numbers of hops to try or 0 for the
529 * default
530 * @param timeout the time, in milliseconds, before the call aborts
531 * @throws IllegalArgumentException if either {@code timeout}
532 * or {@code ttl} are negative.
533 * @return a {@code boolean}indicating if the address is reachable.
534 * @throws IOException if a network error occurs
535 * @since 1.5
536 */
537 public boolean isReachable(NetworkInterface netif, int ttl,
538 int timeout) throws IOException {
539 if (ttl < 0)
540 throw new IllegalArgumentException("ttl can't be negative");
541 if (timeout < 0)
542 throw new IllegalArgumentException("timeout can't be negative");
543
544 return impl.isReachable(this, timeout, netif, ttl);
545 }
546
547 /**
548 * Gets the host name for this IP address.
549 *
550 * <p>If this InetAddress was created with a host name,
551 * this host name will be remembered and returned;
552 * otherwise, a reverse name lookup will be performed
553 * and the result will be returned based on the system
554 * configured name lookup service. If a lookup of the name service
555 * is required, call
556 * {@link #getCanonicalHostName() getCanonicalHostName}.
557 *
558 * <p>If there is a security manager, its
559 * {@code checkConnect} method is first called
560 * with the hostname and {@code -1}
561 * as its arguments to see if the operation is allowed.
562 * If the operation is not allowed, it will return
563 * the textual representation of the IP address.
564 *
565 * @return the host name for this IP address, or if the operation
566 * is not allowed by the security check, the textual
567 * representation of the IP address.
568 *
569 * @see InetAddress#getCanonicalHostName
570 * @see SecurityManager#checkConnect
571 */
572 public String getHostName() {
573 return getHostName(true);
574 }
575
576 /**
577 * Returns the hostname for this address.
578 * If the host is equal to null, then this address refers to any
579 * of the local machine's available network addresses.
580 * this is package private so SocketPermission can make calls into
581 * here without a security check.
582 *
583 * <p>If there is a security manager, this method first
584 * calls its {@code checkConnect} method
585 * with the hostname and {@code -1}
586 * as its arguments to see if the calling code is allowed to know
587 * the hostname for this IP address, i.e., to connect to the host.
588 * If the operation is not allowed, it will return
589 * the textual representation of the IP address.
590 *
591 * @return the host name for this IP address, or if the operation
592 * is not allowed by the security check, the textual
593 * representation of the IP address.
594 *
595 * @param check make security check if true
596 *
597 * @see SecurityManager#checkConnect
598 */
599 String getHostName(boolean check) {
600 if (holder().getHostName() == null) {
601 holder().hostName = InetAddress.getHostFromNameService(this, check);
602 }
603 return holder().getHostName();
604 }
605
606 /**
607 * Gets the fully qualified domain name for this IP address.
608 * Best effort method, meaning we may not be able to return
609 * the FQDN depending on the underlying system configuration.
610 *
611 * <p>If there is a security manager, this method first
612 * calls its {@code checkConnect} method
613 * with the hostname and {@code -1}
614 * as its arguments to see if the calling code is allowed to know
615 * the hostname for this IP address, i.e., to connect to the host.
616 * If the operation is not allowed, it will return
617 * the textual representation of the IP address.
618 *
619 * @return the fully qualified domain name for this IP address,
620 * or if the operation is not allowed by the security check,
621 * the textual representation of the IP address.
622 *
623 * @see SecurityManager#checkConnect
624 *
625 * @since 1.4
626 */
627 public String getCanonicalHostName() {
628 String value = canonicalHostName;
629 if (value == null)
630 canonicalHostName = value =
631 InetAddress.getHostFromNameService(this, true);
632 return value;
633 }
634
635 /**
636 * Returns the hostname for this address.
637 *
638 * <p>If there is a security manager, this method first
639 * calls its {@code checkConnect} method
640 * with the hostname and {@code -1}
641 * as its arguments to see if the calling code is allowed to know
642 * the hostname for this IP address, i.e., to connect to the host.
643 * If the operation is not allowed, it will return
644 * the textual representation of the IP address.
645 *
646 * @return the host name for this IP address, or if the operation
647 * is not allowed by the security check, the textual
648 * representation of the IP address.
649 *
650 * @param check make security check if true
651 *
652 * @see SecurityManager#checkConnect
653 */
654 private static String getHostFromNameService(InetAddress addr, boolean check) {
655 String host = null;
656 try {
657 // first lookup the hostname
658 host = nameService.getHostByAddr(addr.getAddress());
659
660 /* check to see if calling code is allowed to know
661 * the hostname for this IP address, ie, connect to the host
662 */
663 if (check) {
664 SecurityManager sec = System.getSecurityManager();
665 if (sec != null) {
666 sec.checkConnect(host, -1);
667 }
668 }
669
670 /* now get all the IP addresses for this hostname,
671 * and make sure one of them matches the original IP
672 * address. We do this to try and prevent spoofing.
673 */
674
675 InetAddress[] arr = InetAddress.getAllByName0(host, check);
676 boolean ok = false;
677
678 if(arr != null) {
679 for(int i = 0; !ok && i < arr.length; i++) {
680 ok = addr.equals(arr[i]);
681 }
682 }
683
684 //XXX: if it looks a spoof just return the address?
685 if (!ok) {
686 host = addr.getHostAddress();
687 return host;
688 }
689 } catch (SecurityException e) {
690 host = addr.getHostAddress();
691 } catch (UnknownHostException e) {
692 host = addr.getHostAddress();
693 // let next provider resolve the hostname
694 }
695 return host;
696 }
697
698 /**
699 * Returns the raw IP address of this {@code InetAddress}
700 * object. The result is in network byte order: the highest order
701 * byte of the address is in {@code getAddress()[0]}.
702 *
703 * @return the raw IP address of this object.
704 */
705 public byte[] getAddress() {
706 return null;
707 }
708
709 /**
710 * Returns the IP address string in textual presentation.
711 *
712 * @return the raw IP address in a string format.
713 * @since 1.0.2
714 */
715 public String getHostAddress() {
716 return null;
717 }
718
719 /**
720 * Returns a hashcode for this IP address.
721 *
722 * @return a hash code value for this IP address.
723 */
724 public int hashCode() {
725 return -1;
726 }
727
728 /**
729 * Compares this object against the specified object.
730 * The result is {@code true} if and only if the argument is
731 * not {@code null} and it represents the same IP address as
732 * this object.
733 * <p>
734 * Two instances of {@code InetAddress} represent the same IP
735 * address if the length of the byte arrays returned by
736 * {@code getAddress} is the same for both, and each of the
737 * array components is the same for the byte arrays.
738 *
739 * @param obj the object to compare against.
740 * @return {@code true} if the objects are the same;
741 * {@code false} otherwise.
742 * @see java.net.InetAddress#getAddress()
743 */
744 public boolean equals(Object obj) {
745 return false;
746 }
747
748 /**
749 * Converts this IP address to a {@code String}. The
750 * string returned is of the form: hostname / literal IP
751 * address.
752 *
753 * If the host name is unresolved, no reverse name service lookup
754 * is performed. The hostname part will be represented by an empty string.
755 *
756 * @return a string representation of this IP address.
757 */
758 public String toString() {
759 String hostName = holder().getHostName();
760 return Objects.toString(hostName, "")
761 + "/" + getHostAddress();
762 }
763
764 // mapping from host name to Addresses - either NameServiceAddresses (while
765 // still being looked-up by NameService(s)) or CachedAddresses when cached
766 private static final ConcurrentMap<String, Addresses> cache =
767 new ConcurrentHashMap<>();
768
769 // CachedAddresses that have to expire are kept ordered in this NavigableSet
770 // which is scanned on each access
771 private static final NavigableSet<CachedAddresses> expirySet =
772 new ConcurrentSkipListSet<>();
773
774 // common interface
775 private interface Addresses {
776 InetAddress[] get() throws UnknownHostException;
777 }
778
779 // a holder for cached addresses with required metadata
780 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
781 private static final AtomicLong seq = new AtomicLong();
782 final String host;
783 final InetAddress[] inetAddresses;
784 final long expiryTime; // time of expiry (in terms of System.nanoTime())
785 final long id = seq.incrementAndGet(); // each instance is unique
786
787 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
788 this.host = host;
789 this.inetAddresses = inetAddresses;
790 this.expiryTime = expiryTime;
791 }
792
793 @Override
794 public InetAddress[] get() throws UnknownHostException {
795 if (inetAddresses == null) {
796 throw new UnknownHostException(host);
797 }
798 return inetAddresses;
799 }
800
801 @Override
802 public int compareTo(CachedAddresses other) {
803 // natural order is expiry time -
804 // compare difference of expiry times rather than
805 // expiry times directly, to avoid possible overflow.
806 // (see System.nanoTime() recommendations...)
807 long diff = this.expiryTime - other.expiryTime;
808 if (diff < 0L) return -1;
809 if (diff > 0L) return 1;
810 // ties are broken using unique id
811 return Long.compare(this.id, other.id);
812 }
813 }
814
815 // a name service lookup based Addresses implementation which replaces itself
816 // in cache when the result is obtained
817 private static final class NameServiceAddresses implements Addresses {
818 private final String host;
819 private final InetAddress reqAddr;
820
821 NameServiceAddresses(String host, InetAddress reqAddr) {
822 this.host = host;
823 this.reqAddr = reqAddr;
824 }
825
826 @Override
827 public InetAddress[] get() throws UnknownHostException {
828 Addresses addresses;
829 // only one thread is doing lookup to name service
830 // for particular host at any time.
831 synchronized (this) {
832 // re-check that we are still us + re-install us if slot empty
833 addresses = cache.putIfAbsent(host, this);
834 if (addresses == null) {
835 // this can happen when we were replaced by CachedAddresses in
836 // some other thread, then CachedAddresses expired and were
837 // removed from cache while we were waiting for lock...
838 addresses = this;
839 }
840 // still us ?
841 if (addresses == this) {
842 // lookup name services
843 InetAddress[] inetAddresses;
844 UnknownHostException ex;
845 int cachePolicy;
846 try {
847 inetAddresses = getAddressesFromNameService(host, reqAddr);
848 ex = null;
849 cachePolicy = InetAddressCachePolicy.get();
850 } catch (UnknownHostException uhe) {
851 inetAddresses = null;
852 ex = uhe;
853 cachePolicy = InetAddressCachePolicy.getNegative();
854 }
855 // remove or replace us with cached addresses according to cachePolicy
856 if (cachePolicy == InetAddressCachePolicy.NEVER) {
857 cache.remove(host, this);
858 } else {
859 CachedAddresses cachedAddresses = new CachedAddresses(
860 host,
861 inetAddresses,
862 cachePolicy == InetAddressCachePolicy.FOREVER
863 ? 0L
864 // cachePolicy is in [s] - we need [ns]
865 : System.nanoTime() + 1000_000_000L * cachePolicy
866 );
867 if (cache.replace(host, this, cachedAddresses) &&
868 cachePolicy != InetAddressCachePolicy.FOREVER) {
869 // schedule expiry
870 expirySet.add(cachedAddresses);
871 }
872 }
873 if (inetAddresses == null) {
874 throw ex == null ? new UnknownHostException(host) : ex;
875 }
876 return inetAddresses;
877 }
878 // else addresses != this
879 }
880 // delegate to different addresses when we are already replaced
881 // but outside of synchronized block to avoid any chance of dead-locking
882 return addresses.get();
883 }
884 }
885
886 /**
887 * NameService provides host and address lookup service
888 *
889 * @since 9
890 */
891 private interface NameService {
892
893 /**
894 * Lookup a host mapping by name. Retrieve the IP addresses
895 * associated with a host
896 *
897 * @param host the specified hostname
898 * @return array of IP addresses for the requested host
899 * @throws UnknownHostException
900 * if no IP address for the {@code host} could be found
901 */
902 InetAddress[] lookupAllHostAddr(String host)
903 throws UnknownHostException;
904
905 /**
906 * Lookup the host corresponding to the IP address provided
907 *
908 * @param addr byte array representing an IP address
909 * @return {@code String} representing the host name mapping
910 * @throws UnknownHostException
911 * if no host found for the specified IP address
912 */
913 String getHostByAddr(byte[] addr) throws UnknownHostException;
914
915 }
916
917 /**
918 * The default NameService implementation, which delegates to the underlying
919 * OS network libraries to resolve host address mappings.
920 *
921 * @since 9
922 */
923 private static final class PlatformNameService implements NameService {
924
925 public InetAddress[] lookupAllHostAddr(String host)
926 throws UnknownHostException
927 {
928 return impl.lookupAllHostAddr(host);
929 }
930
931 public String getHostByAddr(byte[] addr)
932 throws UnknownHostException
933 {
934 return impl.getHostByAddr(addr);
935 }
936 }
937
938 /**
939 * The HostsFileNameService provides host address mapping
940 * by reading the entries in a hosts file, which is specified by
941 * {@code jdk.net.hosts.file} system property
942 *
943 * <p>The file format is that which corresponds with the /etc/hosts file
944 * IP Address host alias list.
945 *
946 * <p>When the file lookup is enabled it replaces the default NameService
947 * implementation
948 *
949 * @since 9
950 */
951 private static final class HostsFileNameService implements NameService {
952
953 private final String hostsFile;
954
955 public HostsFileNameService (String hostsFileName) {
956 this.hostsFile = hostsFileName;
957 }
958
959 private String addrToString(byte addr[]) {
960 String stringifiedAddress = null;
961
962 if (addr.length == Inet4Address.INADDRSZ) {
963 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
964 } else { // treat as an IPV6 jobby
965 byte[] newAddr
966 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
967 if (newAddr != null) {
968 stringifiedAddress = Inet4Address.numericToTextFormat(addr);
969 } else {
970 stringifiedAddress = Inet6Address.numericToTextFormat(addr);
971 }
972 }
973 return stringifiedAddress;
974 }
975
976 /**
977 * Lookup the host name corresponding to the IP address provided.
978 * Search the configured host file a host name corresponding to
979 * the specified IP address.
980 *
981 * @param addr byte array representing an IP address
982 * @return {@code String} representing the host name mapping
983 * @throws UnknownHostException
984 * if no host found for the specified IP address
985 */
986 @Override
987 public String getHostByAddr(byte[] addr) throws UnknownHostException {
988 String hostEntry;
989 String host = null;
990
991 String addrString = addrToString(addr);
992 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
993 while (hostsFileScanner.hasNextLine()) {
994 hostEntry = hostsFileScanner.nextLine();
995 if (!hostEntry.startsWith("#")) {
996 hostEntry = removeComments(hostEntry);
997 if (hostEntry.contains(addrString)) {
998 host = extractHost(hostEntry, addrString);
999 if (host != null) {
1000 break;
1001 }
1002 }
1003 }
1004 }
1005 } catch (FileNotFoundException e) {
1006 throw new UnknownHostException("Unable to resolve address "
1007 + addrString + " as hosts file " + hostsFile
1008 + " not found ");
1009 }
1010
1011 if ((host == null) || (host.equals("")) || (host.equals(" "))) {
1012 throw new UnknownHostException("Requested address "
1013 + addrString
1014 + " resolves to an invalid entry in hosts file "
1015 + hostsFile);
1016 }
1017 return host;
1018 }
1019
1020 /**
1021 * <p>Lookup a host mapping by name. Retrieve the IP addresses
1022 * associated with a host.
1023 *
1024 * <p>Search the configured hosts file for the addresses assocaited with
1025 * with the specified host name.
1026 *
1027 * @param host the specified hostname
1028 * @return array of IP addresses for the requested host
1029 * @throws UnknownHostException
1030 * if no IP address for the {@code host} could be found
1031 */
1032 public InetAddress[] lookupAllHostAddr(String host)
1033 throws UnknownHostException {
1034 String hostEntry;
1035 String addrStr = null;
1036 InetAddress[] res = null;
1037 byte addr[] = new byte[4];
1038 ArrayList<InetAddress> inetAddresses = null;
1039
1040 // lookup the file and create a list InetAddress for the specfied host
1041 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
1042 while (hostsFileScanner.hasNextLine()) {
1043 hostEntry = hostsFileScanner.nextLine();
1044 if (!hostEntry.startsWith("#")) {
1045 hostEntry = removeComments(hostEntry);
1046 if (hostEntry.contains(host)) {
1047 addrStr = extractHostAddr(hostEntry, host);
1048 if ((addrStr != null) && (!addrStr.equals(""))) {
1049 addr = createAddressByteArray(addrStr);
1050 if (inetAddresses == null) {
1051 inetAddresses = new ArrayList<>(1);
1052 }
1053 if (addr != null) {
1054 inetAddresses.add(InetAddress.getByAddress(host, addr));
1055 }
1056 }
1057 }
1058 }
1059 }
1060 } catch (FileNotFoundException e) {
1061 throw new UnknownHostException("Unable to resolve host " + host
1062 + " as hosts file " + hostsFile + " not found ");
1063 }
1064
1065 if (inetAddresses != null) {
1066 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]);
1067 } else {
1068 throw new UnknownHostException("Unable to resolve host " + host
1069 + " in hosts file " + hostsFile);
1070 }
1071 return res;
1072 }
1073
1074 private String removeComments(String hostsEntry) {
1075 String filteredEntry = hostsEntry;
1076 int hashIndex;
1077
1078 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1079 filteredEntry = hostsEntry.substring(0, hashIndex);
1080 }
1081 return filteredEntry;
1082 }
1083
1084 private byte [] createAddressByteArray(String addrStr) {
1085 byte[] addrArray;
1086 // check if IPV4 address - most likely
1087 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr);
1088 if (addrArray == null) {
1089 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr);
1090 }
1091 return addrArray;
1092 }
1093
1094 /** host to ip address mapping */
1095 private String extractHostAddr(String hostEntry, String host) {
1096 String[] mapping = hostEntry.split("\\s+");
1097 String hostAddr = null;
1098
1099 if (mapping.length >= 2) {
1100 // look at the host aliases
1101 for (int i = 1; i < mapping.length; i++) {
1102 if (mapping[i].equalsIgnoreCase(host)) {
1103 hostAddr = mapping[0];
1104 }
1105 }
1106 }
1107 return hostAddr;
1108 }
1109
1110 /**
1111 * IP Address to host mapping
1112 * use first host alias in list
1113 */
1114 private String extractHost(String hostEntry, String addrString) {
1115 String[] mapping = hostEntry.split("\\s+");
1116 String host = null;
1117
1118 if (mapping.length >= 2) {
1119 if (mapping[0].equalsIgnoreCase(addrString)) {
1120 host = mapping[1];
1121 }
1122 }
1123 return host;
1124 }
1125 }
1126
1127 static final InetAddressImpl impl;
1128
1129 static {
1130 // create the impl
1131 impl = InetAddressImplFactory.create();
1132
1133 // create name service
1134 nameService = createNameService();
1135 }
1136
1137 /**
1138 * Create an instance of the NameService interface based on
1139 * the setting of the {@code jdk.net.hosts.file} system property.
1140 *
1141 * <p>The default NameService is the PlatformNameService, which typically
1142 * delegates name and address resolution calls to the underlying
1143 * OS network libraries.
1144 *
1145 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1146 * system property is set. If the specified file doesn't exist, the name or
1147 * address lookup will result in an UnknownHostException. Thus, non existent
1148 * hosts file is handled as if the file is empty.
1149 *
1150 * @return a NameService
1151 */
1152 private static NameService createNameService() {
1153
1154 String hostsFileName =
1155 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file");
1156 NameService theNameService;
1157 if (hostsFileName != null) {
1158 theNameService = new HostsFileNameService(hostsFileName);
1159 } else {
1160 theNameService = new PlatformNameService();
1161 }
1162 return theNameService;
1163 }
1164
1165 /**
1166 * Creates an InetAddress based on the provided host name and IP address.
1167 * No name service is checked for the validity of the address.
1168 *
1169 * <p> The host name can either be a machine name, such as
1170 * "{@code java.sun.com}", or a textual representation of its IP
1171 * address.
1172 * <p> No validity checking is done on the host name either.
1173 *
1174 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1175 * will be returned; otherwise, an instance of Inet6Address
1176 * will be returned.
1177 *
1178 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1179 * must be 16 bytes long
1180 *
1181 * @param host the specified host
1182 * @param addr the raw IP address in network byte order
1183 * @return an InetAddress object created from the raw IP address.
1184 * @exception UnknownHostException if IP address is of illegal length
1185 * @since 1.4
1186 */
1187 public static InetAddress getByAddress(String host, byte[] addr)
1188 throws UnknownHostException {
1189 if (host != null && host.length() > 0 && host.charAt(0) == '[') {
1190 if (host.charAt(host.length()-1) == ']') {
1191 host = host.substring(1, host.length() -1);
1192 }
1193 }
1194 if (addr != null) {
1195 if (addr.length == Inet4Address.INADDRSZ) {
1196 return new Inet4Address(host, addr);
1197 } else if (addr.length == Inet6Address.INADDRSZ) {
1198 byte[] newAddr
1199 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1200 if (newAddr != null) {
1201 return new Inet4Address(host, newAddr);
1202 } else {
1203 return new Inet6Address(host, addr);
1204 }
1205 }
1206 }
1207 throw new UnknownHostException("addr is of illegal length");
1208 }
1209
1210
1211 /**
1212 * Determines the IP address of a host, given the host's name.
1213 *
1214 * <p> The host name can either be a machine name, such as
1215 * "{@code java.sun.com}", or a textual representation of its
1216 * IP address. If a literal IP address is supplied, only the
1217 * validity of the address format is checked.
1218 *
1219 * <p> For {@code host} specified in literal IPv6 address,
1220 * either the form defined in RFC 2732 or the literal IPv6 address
1221 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1222 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1223 * scoped addresses.
1224 *
1225 * <p> If the host is {@code null} or {@code host.length()} is equal
1226 * to zero, then an {@code InetAddress} representing an address of the
1227 * loopback interface is returned.
1228 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1229 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1230 * section 2.5.3.
1231 *
1232 * <p> If there is a security manager, and {@code host} is not {@code null}
1233 * or {@code host.length() } is not equal to zero, the security manager's
1234 * {@code checkConnect} method is called with the hostname and {@code -1}
1235 * as its arguments to determine if the operation is allowed.
1236 *
1237 * @param host the specified host, or {@code null}.
1238 * @return an IP address for the given host name.
1239 * @exception UnknownHostException if no IP address for the
1240 * {@code host} could be found, or if a scope_id was specified
1241 * for a global IPv6 address.
1242 * @exception SecurityException if a security manager exists
1243 * and its checkConnect method doesn't allow the operation
1244 */
1245 public static InetAddress getByName(String host)
1246 throws UnknownHostException {
1247 return InetAddress.getAllByName(host)[0];
1248 }
1249
1250 // called from deployment cache manager
1251 private static InetAddress getByName(String host, InetAddress reqAddr)
1252 throws UnknownHostException {
1253 return InetAddress.getAllByName(host, reqAddr)[0];
1254 }
1255
1256 /**
1257 * Given the name of a host, returns an array of its IP addresses,
1258 * based on the configured name service on the system.
1259 *
1260 * <p> The host name can either be a machine name, such as
1261 * "{@code java.sun.com}", or a textual representation of its IP
1262 * address. If a literal IP address is supplied, only the
1263 * validity of the address format is checked.
1264 *
1265 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1266 * either the form defined in RFC 2732 or the literal IPv6 address
1267 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1268 * also be qualified by appending a scoped zone identifier or scope_id.
1269 * The syntax and usage of scope_ids is described
1270 * <a href="Inet6Address.html#scoped">here</a>.
1271 *
1272 * <p> If the host is {@code null} or {@code host.length()} is equal
1273 * to zero, then an {@code InetAddress} representing an address of the
1274 * loopback interface is returned.
1275 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1276 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1277 * section 2.5.3. </p>
1278 *
1279 * <p> If there is a security manager, and {@code host} is not {@code null}
1280 * or {@code host.length() } is not equal to zero, the security manager's
1281 * {@code checkConnect} method is called with the hostname and {@code -1}
1282 * as its arguments to determine if the operation is allowed.
1283 *
1284 * @param host the name of the host, or {@code null}.
1285 * @return an array of all the IP addresses for a given host name.
1286 *
1287 * @exception UnknownHostException if no IP address for the
1288 * {@code host} could be found, or if a scope_id was specified
1289 * for a global IPv6 address.
1290 * @exception SecurityException if a security manager exists and its
1291 * {@code checkConnect} method doesn't allow the operation.
1292 *
1293 * @see SecurityManager#checkConnect
1294 */
1295 public static InetAddress[] getAllByName(String host)
1296 throws UnknownHostException {
1297 return getAllByName(host, null);
1298 }
1299
1300 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1301 throws UnknownHostException {
1302
1303 if (host == null || host.length() == 0) {
1304 InetAddress[] ret = new InetAddress[1];
1305 ret[0] = impl.loopbackAddress();
1306 return ret;
1307 }
1308
1309 boolean ipv6Expected = false;
1310 if (host.charAt(0) == '[') {
1311 // This is supposed to be an IPv6 literal
1312 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1313 host = host.substring(1, host.length() -1);
1314 ipv6Expected = true;
1315 } else {
1316 // This was supposed to be a IPv6 address, but it's not!
1317 throw new UnknownHostException(host + ": invalid IPv6 address");
1318 }
1319 }
1320
1321 // if host is an IP address, we won't do further lookup
1322 if (Character.digit(host.charAt(0), 16) != -1
1323 || (host.charAt(0) == ':')) {
1324 byte[] addr = null;
1325 int numericZone = -1;
1326 String ifname = null;
1327 // see if it is IPv4 address
1328 addr = IPAddressUtil.textToNumericFormatV4(host);
1329 if (addr == null) {
1330 // This is supposed to be an IPv6 literal
1331 // Check if a numeric or string zone id is present
1332 int pos;
1333 if ((pos=host.indexOf ('%')) != -1) {
1334 numericZone = checkNumericZone (host);
1335 if (numericZone == -1) { /* remainder of string must be an ifname */
1336 ifname = host.substring (pos+1);
1337 }
1338 }
1339 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1340 throw new UnknownHostException(host + ": invalid IPv6 address");
1341 }
1342 } else if (ipv6Expected) {
1343 // Means an IPv4 litteral between brackets!
1344 throw new UnknownHostException("["+host+"]");
1345 }
1346 InetAddress[] ret = new InetAddress[1];
1347 if(addr != null) {
1348 if (addr.length == Inet4Address.INADDRSZ) {
1349 ret[0] = new Inet4Address(null, addr);
1350 } else {
1351 if (ifname != null) {
1352 ret[0] = new Inet6Address(null, addr, ifname);
1353 } else {
1354 ret[0] = new Inet6Address(null, addr, numericZone);
1355 }
1356 }
1357 return ret;
1358 }
1359 } else if (ipv6Expected) {
1360 // We were expecting an IPv6 Litteral, but got something else
1361 throw new UnknownHostException("["+host+"]");
1362 }
1363 return getAllByName0(host, reqAddr, true, true);
1364 }
1365
1366 /**
1367 * Returns the loopback address.
1368 * <p>
1369 * The InetAddress returned will represent the IPv4
1370 * loopback address, 127.0.0.1, or the IPv6 loopback
1371 * address, ::1. The IPv4 loopback address returned
1372 * is only one of many in the form 127.*.*.*
1373 *
1374 * @return the InetAddress loopback instance.
1375 * @since 1.7
1376 */
1377 public static InetAddress getLoopbackAddress() {
1378 return impl.loopbackAddress();
1379 }
1380
1381
1382 /**
1383 * check if the literal address string has %nn appended
1384 * returns -1 if not, or the numeric value otherwise.
1385 *
1386 * %nn may also be a string that represents the displayName of
1387 * a currently available NetworkInterface.
1388 */
1389 private static int checkNumericZone (String s) throws UnknownHostException {
1390 int percent = s.indexOf ('%');
1391 int slen = s.length();
1392 int digit, zone=0;
1393 if (percent == -1) {
1394 return -1;
1395 }
1396 for (int i=percent+1; i<slen; i++) {
1397 char c = s.charAt(i);
1398 if (c == ']') {
1399 if (i == percent+1) {
1400 /* empty per-cent field */
1401 return -1;
1402 }
1403 break;
1404 }
1405 if ((digit = Character.digit (c, 10)) < 0) {
1406 return -1;
1407 }
1408 zone = (zone * 10) + digit;
1409 }
1410 return zone;
1411 }
1412
1413 private static InetAddress[] getAllByName0 (String host)
1414 throws UnknownHostException
1415 {
1416 return getAllByName0(host, true);
1417 }
1418
1419 /**
1420 * package private so SocketPermission can call it
1421 */
1422 static InetAddress[] getAllByName0 (String host, boolean check)
1423 throws UnknownHostException {
1424 return getAllByName0 (host, null, check, true);
1425 }
1426
1427 /**
1428 * Designated lookup method.
1429 *
1430 * @param host host name to look up
1431 * @param reqAddr requested address to be the 1st in returned array
1432 * @param check perform security check
1433 * @param useCache use cached value if not expired else always
1434 * perform name service lookup (and cache the result)
1435 * @return array of InetAddress(es)
1436 * @throws UnknownHostException if host name is not found
1437 */
1438 private static InetAddress[] getAllByName0(String host,
1439 InetAddress reqAddr,
1440 boolean check,
1441 boolean useCache)
1442 throws UnknownHostException {
1443
1444 /* If it gets here it is presumed to be a hostname */
1445
1446 /* make sure the connection to the host is allowed, before we
1447 * give out a hostname
1448 */
1449 if (check) {
1450 SecurityManager security = System.getSecurityManager();
1451 if (security != null) {
1452 security.checkConnect(host, -1);
1453 }
1454 }
1455
1456 // remove expired addresses from cache - expirySet keeps them ordered
1457 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1458 long now = System.nanoTime();
1459 for (CachedAddresses caddrs : expirySet) {
1460 // compare difference of time instants rather than
1461 // time instants directly, to avoid possible overflow.
1462 // (see System.nanoTime() recommendations...)
1463 if ((caddrs.expiryTime - now) < 0L) {
1464 // ConcurrentSkipListSet uses weakly consistent iterator,
1465 // so removing while iterating is OK...
1466 if (expirySet.remove(caddrs)) {
1467 // ... remove from cache
1468 cache.remove(caddrs.host, caddrs);
1469 }
1470 } else {
1471 // we encountered 1st element that expires in future
1472 break;
1473 }
1474 }
1475
1476 // look-up or remove from cache
1477 Addresses addrs;
1478 if (useCache) {
1479 addrs = cache.get(host);
1480 } else {
1481 addrs = cache.remove(host);
1482 if (addrs != null) {
1483 if (addrs instanceof CachedAddresses) {
1484 // try removing from expirySet too if CachedAddresses
1485 expirySet.remove(addrs);
1486 }
1487 addrs = null;
1488 }
1489 }
1490
1491 if (addrs == null) {
1492 // create a NameServiceAddresses instance which will look up
1493 // the name service and install it within cache...
1494 Addresses oldAddrs = cache.putIfAbsent(
1495 host,
1496 addrs = new NameServiceAddresses(host, reqAddr)
1497 );
1498 if (oldAddrs != null) { // lost putIfAbsent race
1499 addrs = oldAddrs;
1500 }
1501 }
1502
1503 // ask Addresses to get an array of InetAddress(es) and clone it
1504 return addrs.get().clone();
1505 }
1506
1507 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1508 throws UnknownHostException
1509 {
1510 InetAddress[] addresses = null;
1511 UnknownHostException ex = null;
1512
1513 try {
1514 addresses = nameService.lookupAllHostAddr(host);
1515 } catch (UnknownHostException uhe) {
1516 if (host.equalsIgnoreCase("localhost")) {
1517 addresses = new InetAddress[] { impl.loopbackAddress() };
1518 }
1519 else {
1520 ex = uhe;
1521 }
1522 }
1523
1524 if (addresses == null) {
1525 throw ex == null ? new UnknownHostException(host) : ex;
1526 }
1527
1528 // More to do?
1529 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1530 // Find it?
1531 int i = 1;
1532 for (; i < addresses.length; i++) {
1533 if (addresses[i].equals(reqAddr)) {
1534 break;
1535 }
1536 }
1537 // Rotate
1538 if (i < addresses.length) {
1539 InetAddress tmp, tmp2 = reqAddr;
1540 for (int j = 0; j < i; j++) {
1541 tmp = addresses[j];
1542 addresses[j] = tmp2;
1543 tmp2 = tmp;
1544 }
1545 addresses[i] = tmp2;
1546 }
1547 }
1548
1549 return addresses;
1550 }
1551
1552 /**
1553 * Returns an {@code InetAddress} object given the raw IP address .
1554 * The argument is in network byte order: the highest order
1555 * byte of the address is in {@code getAddress()[0]}.
1556 *
1557 * <p> This method doesn't block, i.e. no reverse name service lookup
1558 * is performed.
1559 *
1560 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1561 * must be 16 bytes long
1562 *
1563 * @param addr the raw IP address in network byte order
1564 * @return an InetAddress object created from the raw IP address.
1565 * @exception UnknownHostException if IP address is of illegal length
1566 * @since 1.4
1567 */
1568 public static InetAddress getByAddress(byte[] addr)
1569 throws UnknownHostException {
1570 return getByAddress(null, addr);
1571 }
1572
1573 private static final class CachedLocalHost {
1574 final String host;
1575 final InetAddress addr;
1576 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1577
1578 CachedLocalHost(String host, InetAddress addr) {
1579 this.host = host;
1580 this.addr = addr;
1581 }
1582 }
1583
1584 private static volatile CachedLocalHost cachedLocalHost;
1585
1586 /**
1587 * Returns the address of the local host. This is achieved by retrieving
1588 * the name of the host from the system, then resolving that name into
1589 * an {@code InetAddress}.
1590 *
1591 * <P>Note: The resolved address may be cached for a short period of time.
1592 * </P>
1593 *
1594 * <p>If there is a security manager, its
1595 * {@code checkConnect} method is called
1596 * with the local host name and {@code -1}
1597 * as its arguments to see if the operation is allowed.
1598 * If the operation is not allowed, an InetAddress representing
1599 * the loopback address is returned.
1600 *
1601 * @return the address of the local host.
1602 *
1603 * @exception UnknownHostException if the local host name could not
1604 * be resolved into an address.
1605 *
1606 * @see SecurityManager#checkConnect
1607 * @see java.net.InetAddress#getByName(java.lang.String)
1608 */
1609 public static InetAddress getLocalHost() throws UnknownHostException {
1610
1611 SecurityManager security = System.getSecurityManager();
1612 try {
1613 // is cached data still valid?
1614 CachedLocalHost clh = cachedLocalHost;
1615 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1616 if (security != null) {
1617 security.checkConnect(clh.host, -1);
1618 }
1619 return clh.addr;
1620 }
1621
1622 String local = impl.getLocalHostName();
1623
1624 if (security != null) {
1625 security.checkConnect(local, -1);
1626 }
1627
1628 InetAddress localAddr;
1629 if (local.equals("localhost")) {
1630 // shortcut for "localhost" host name
1631 localAddr = impl.loopbackAddress();
1632 } else {
1633 // call getAllByName0 without security checks and
1634 // without using cached data
1635 try {
1636 localAddr = getAllByName0(local, null, false, false)[0];
1637 } catch (UnknownHostException uhe) {
1638 // Rethrow with a more informative error message.
1639 UnknownHostException uhe2 =
1640 new UnknownHostException(local + ": " +
1641 uhe.getMessage());
1642 uhe2.initCause(uhe);
1643 throw uhe2;
1644 }
1645 }
1646 cachedLocalHost = new CachedLocalHost(local, localAddr);
1647 return localAddr;
1648 } catch (java.lang.SecurityException e) {
1649 return impl.loopbackAddress();
1650 }
1651 }
1652
1653 /**
1654 * Perform class load-time initializations.
1655 */
1656 private static native void init();
1657
1658
1659 /*
1660 * Returns the InetAddress representing anyLocalAddress
1661 * (typically 0.0.0.0 or ::0)
1662 */
1663 static InetAddress anyLocalAddress() {
1664 return impl.anyLocalAddress();
1665 }
1666
1667 /*
1668 * Load and instantiate an underlying impl class
1669 */
1670 static InetAddressImpl loadImpl(String implName) {
1671 Object impl = null;
1672
1673 /*
1674 * Property "impl.prefix" will be prepended to the classname
1675 * of the implementation object we instantiate, to which we
1676 * delegate the real work (like native methods). This
1677 * property can vary across implementations of the java.
1678 * classes. The default is an empty String "".
1679 */
1680 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", "");
1681 try {
1682 @SuppressWarnings("deprecation")
1683 Object tmp = Class.forName("java.net." + prefix + implName).newInstance();
1684 impl = tmp;
1685 } catch (ClassNotFoundException e) {
1686 System.err.println("Class not found: java.net." + prefix +
1687 implName + ":\ncheck impl.prefix property " +
1688 "in your properties file.");
1689 } catch (InstantiationException e) {
1690 System.err.println("Could not instantiate: java.net." + prefix +
1691 implName + ":\ncheck impl.prefix property " +
1692 "in your properties file.");
1693 } catch (IllegalAccessException e) {
1694 System.err.println("Cannot access class: java.net." + prefix +
1695 implName + ":\ncheck impl.prefix property " +
1696 "in your properties file.");
1697 }
1698
1699 if (impl == null) {
1700 try {
1701 @SuppressWarnings("deprecation")
1702 Object tmp = Class.forName(implName).newInstance();
1703 impl = tmp;
1704 } catch (Exception e) {
1705 throw new Error("System property impl.prefix incorrect");
1706 }
1707 }
1708
1709 return (InetAddressImpl) impl;
1710 }
1711
1712 private void readObjectNoData () {
1713 if (getClass().getClassLoader() != null) {
1714 throw new SecurityException ("invalid address type");
1715 }
1716 }
1717
1718 private static final jdk.internal.misc.Unsafe UNSAFE
1719 = jdk.internal.misc.Unsafe.getUnsafe();
1720 private static final long FIELDS_OFFSET
1721 = UNSAFE.objectFieldOffset(InetAddress.class, "holder");
1722
1723 private void readObject (ObjectInputStream s) throws
1724 IOException, ClassNotFoundException {
1725 if (getClass().getClassLoader() != null) {
1726 throw new SecurityException ("invalid address type");
1727 }
1728 GetField gf = s.readFields();
1729 String host = (String)gf.get("hostName", null);
1730 int address= gf.get("address", 0);
1731 int family= gf.get("family", 0);
1732 InetAddressHolder h = new InetAddressHolder(host, address, family);
1733 UNSAFE.putObject(this, FIELDS_OFFSET, h);
1734 }
1735
1736 /* needed because the serializable fields no longer exist */
1737
1738 /**
1739 * @serialField hostName String
1740 * @serialField address int
1741 * @serialField family int
1742 */
1743 private static final ObjectStreamField[] serialPersistentFields = {
1744 new ObjectStreamField("hostName", String.class),
1745 new ObjectStreamField("address", int.class),
1746 new ObjectStreamField("family", int.class),
1747 };
1748
1749 private void writeObject (ObjectOutputStream s) throws
1750 IOException {
1751 if (getClass().getClassLoader() != null) {
1752 throw new SecurityException ("invalid address type");
1753 }
1754 PutField pf = s.putFields();
1755 pf.put("hostName", holder().getHostName());
1756 pf.put("address", holder().getAddress());
1757 pf.put("family", holder().getFamily());
1758 s.writeFields();
1759 }
1760 }
1761
1762 /*
1763 * Simple factory to create the impl
1764 */
1765 class InetAddressImplFactory {
1766
1767 static InetAddressImpl create() {
1768 return InetAddress.loadImpl(isIPv6Supported() ?
1769 "Inet6AddressImpl" : "Inet4AddressImpl");
1770 }
1771
1772 static native boolean isIPv6Supported();
1773 }