1 /*
2 * Copyright (c) 1995, 2016, 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.Iterator;
30 import java.util.List;
31 import java.util.ArrayList;
32 import java.util.Objects;
33 import java.util.Scanner;
34 import java.security.AccessController;
35 import java.io.File;
36 import java.io.FileNotFoundException;
37 import java.io.ObjectStreamException;
38 import java.io.ObjectStreamField;
39 import java.io.IOException;
40 import java.io.ObjectInputStream;
41 import java.io.ObjectInputStream.GetField;
42 import java.io.ObjectOutputStream;
43 import java.io.ObjectOutputStream.PutField;
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
49 import jdk.internal.misc.JavaNetInetAddressAccess;
50 import jdk.internal.misc.SharedSecrets;
51 import sun.security.action.*;
52 import sun.net.InetAddressCachePolicy;
53 import sun.net.util.IPAddressUtil;
54
55 /**
56 * This class represents an Internet Protocol (IP) address.
57 *
58 * <p> An IP address is either a 32-bit or 128-bit unsigned number
59 * used by IP, a lower-level protocol on which protocols like UDP and
60 * TCP are built. The IP address architecture is defined by <a
61 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790:
62 * Assigned Numbers</i></a>, <a
63 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918:
64 * Address Allocation for Private Internets</i></a>, <a
65 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365:
66 * Administratively Scoped IP Multicast</i></a>, and <a
67 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP
68 * Version 6 Addressing Architecture</i></a>. An instance of an
69 * InetAddress consists of an IP address and possibly its
70 * corresponding host name (depending on whether it is constructed
71 * with a host name or whether it has already done reverse host name
72 * resolution).
73 *
74 * <h3> Address types </h3>
75 *
76 * <blockquote><table cellspacing=2 summary="Description of unicast and multicast address types">
77 * <tr><th valign=top><i>unicast</i></th>
78 * <td>An identifier for a single interface. A packet sent to
79 * a unicast address is delivered to the interface identified by
80 * that address.
81 *
82 * <p> The Unspecified Address -- Also called anylocal or wildcard
83 * address. It must never be assigned to any node. It indicates the
84 * absence of an address. One example of its use is as the target of
85 * bind, which allows a server to accept a client connection on any
86 * interface, in case the server host has multiple interfaces.
87 *
88 * <p> The <i>unspecified</i> address must not be used as
89 * the destination address of an IP packet.
90 *
91 * <p> The <i>Loopback</i> Addresses -- This is the address
92 * assigned to the loopback interface. Anything sent to this
93 * IP address loops around and becomes IP input on the local
94 * host. This address is often used when testing a
95 * client.</td></tr>
96 * <tr><th valign=top><i>multicast</i></th>
97 * <td>An identifier for a set of interfaces (typically belonging
98 * to different nodes). A packet sent to a multicast address is
99 * delivered to all interfaces identified by that address.</td></tr>
100 * </table></blockquote>
101 *
102 * <h4> IP address scope </h4>
103 *
104 * <p> <i>Link-local</i> addresses are designed to be used for addressing
105 * on a single link for purposes such as auto-address configuration,
106 * neighbor discovery, or when no routers are present.
107 *
108 * <p> <i>Site-local</i> addresses are designed to be used for addressing
109 * inside of a site without the need for a global prefix.
110 *
111 * <p> <i>Global</i> addresses are unique across the internet.
112 *
113 * <h4> Textual representation of IP addresses </h4>
114 *
115 * The textual representation of an IP address is address family specific.
116 *
117 * <p>
118 *
119 * For IPv4 address format, please refer to <A
120 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6
121 * address format, please refer to <A
122 * HREF="Inet6Address.html#format">Inet6Address#format</A>.
123 *
124 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of
125 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P>
126 *
127 * <h4> Host Name Resolution </h4>
128 *
129 * Host name-to-IP address <i>resolution</i> is accomplished through
130 * the use of a combination of local machine configuration information
131 * and network naming services such as the Domain Name System (DNS)
132 * and Network Information Service(NIS). The particular naming
133 * services(s) being used is by default the local machine configured
134 * one. For any host name, its corresponding IP address is returned.
135 *
136 * <p> <i>Reverse name resolution</i> means that for any IP address,
137 * the host associated with the IP address is returned.
138 *
139 * <p> The InetAddress class provides methods to resolve host names to
140 * their IP addresses and vice versa.
141 *
142 * <h4> InetAddress Caching </h4>
143 *
144 * The InetAddress class has a cache to store successful as well as
145 * unsuccessful host name resolutions.
146 *
147 * <p> By default, when a security manager is installed, in order to
148 * protect against DNS spoofing attacks,
149 * the result of positive host name resolutions are
150 * cached forever. When a security manager is not installed, the default
151 * behavior is to cache entries for a finite (implementation dependent)
152 * period of time. The result of unsuccessful host
153 * name resolution is cached for a very short period of time (10
154 * seconds) to improve performance.
155 *
156 * <p> If the default behavior is not desired, then a Java security property
157 * can be set to a different Time-to-live (TTL) value for positive
158 * caching. Likewise, a system admin can configure a different
159 * negative caching TTL value when needed.
160 *
161 * <p> Two Java security properties control the TTL values used for
162 * positive and negative host name resolution caching:
163 *
164 * <blockquote>
165 * <dl>
166 * <dt><b>networkaddress.cache.ttl</b></dt>
167 * <dd>Indicates the caching policy for successful name lookups from
168 * the name service. The value is specified as an integer to indicate
169 * the number of seconds to cache the successful lookup. The default
170 * setting is to cache for an implementation specific period of time.
171 * <p>
172 * A value of -1 indicates "cache forever".
173 * </dd>
174 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt>
175 * <dd>Indicates the caching policy for un-successful name lookups
176 * from the name service. The value is specified as an integer to
177 * indicate the number of seconds to cache the failure for
178 * un-successful lookups.
179 * <p>
180 * A value of 0 indicates "never cache".
181 * A value of -1 indicates "cache forever".
182 * </dd>
183 * </dl>
184 * </blockquote>
185 *
186 * @author Chris Warth
187 * @see java.net.InetAddress#getByAddress(byte[])
188 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[])
189 * @see java.net.InetAddress#getAllByName(java.lang.String)
190 * @see java.net.InetAddress#getByName(java.lang.String)
191 * @see java.net.InetAddress#getLocalHost()
192 * @since 1.0
193 */
194 public
195 class InetAddress implements java.io.Serializable {
196 /**
197 * Specify the address family: Internet Protocol, Version 4
198 * @since 1.4
199 */
200 static final int IPv4 = 1;
201
202 /**
203 * Specify the address family: Internet Protocol, Version 6
204 * @since 1.4
205 */
206 static final int IPv6 = 2;
207
208 /* Specify address family preference */
209 static transient boolean preferIPv6Address = false;
210
211
212 static class InetAddressHolder {
213 /**
214 * Reserve the original application specified hostname.
215 *
216 * The original hostname is useful for domain-based endpoint
217 * identification (see RFC 2818 and RFC 6125). If an address
218 * was created with a raw IP address, a reverse name lookup
219 * may introduce endpoint identification security issue via
220 * DNS forging.
221 *
222 * Oracle JSSE provider is using this original hostname, via
223 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification.
224 *
225 * Note: May define a new public method in the future if necessary.
226 */
227 String originalHostName;
228
229 InetAddressHolder() {}
230
231 InetAddressHolder(String hostName, int address, int family) {
232 this.originalHostName = hostName;
233 this.hostName = hostName;
234 this.address = address;
235 this.family = family;
236 }
237
238 void init(String hostName, int family) {
239 this.originalHostName = hostName;
240 this.hostName = hostName;
241 if (family != -1) {
242 this.family = family;
243 }
244 }
245
246 String hostName;
247
248 String getHostName() {
249 return hostName;
250 }
251
252 String getOriginalHostName() {
253 return originalHostName;
254 }
255
256 /**
257 * Holds a 32-bit IPv4 address.
258 */
259 int address;
260
261 int getAddress() {
262 return address;
263 }
264
265 /**
266 * Specifies the address family type, for instance, '1' for IPv4
267 * addresses, and '2' for IPv6 addresses.
268 */
269 int family;
270
271 int getFamily() {
272 return family;
273 }
274 }
275
276 /* Used to store the serializable fields of InetAddress */
277 final transient InetAddressHolder holder;
278
279 InetAddressHolder holder() {
280 return holder;
281 }
282
283 /* Used to store the name service provider */
284 private static NameService nameService = null;
285
286 /* Used to store the best available hostname */
287 private transient String canonicalHostName = null;
288
289 /** use serialVersionUID from JDK 1.0.2 for interoperability */
290 private static final long serialVersionUID = 3286316764910316507L;
291
292 /*
293 * Load net library into runtime, and perform initializations.
294 */
295 static {
296 preferIPv6Address = java.security.AccessController.doPrivileged(
297 new GetBooleanAction("java.net.preferIPv6Addresses")).booleanValue();
298 AccessController.doPrivileged(
299 new java.security.PrivilegedAction<>() {
300 public Void run() {
301 System.loadLibrary("net");
302 return null;
303 }
304 });
305 SharedSecrets.setJavaNetInetAddressAccess(
306 new JavaNetInetAddressAccess() {
307 public String getOriginalHostName(InetAddress ia) {
308 return ia.holder.getOriginalHostName();
309 }
310 }
311 );
312 init();
313 }
314
315 /**
316 * Constructor for the Socket.accept() method.
317 * This creates an empty InetAddress, which is filled in by
318 * the accept() method. This InetAddress, however, is not
319 * put in the address cache, since it is not created by name.
320 */
321 InetAddress() {
322 holder = new InetAddressHolder();
323 }
324
325 /**
326 * Replaces the de-serialized object with an Inet4Address object.
327 *
328 * @return the alternate object to the de-serialized object.
329 *
330 * @throws ObjectStreamException if a new object replacing this
331 * object could not be created
332 */
333 private Object readResolve() throws ObjectStreamException {
334 // will replace the deserialized 'this' object
335 return new Inet4Address(holder().getHostName(), holder().getAddress());
336 }
337
338 /**
339 * Utility routine to check if the InetAddress is an
340 * IP multicast address.
341 * @return a {@code boolean} indicating if the InetAddress is
342 * an IP multicast address
343 * @since 1.1
344 */
345 public boolean isMulticastAddress() {
346 return false;
347 }
348
349 /**
350 * Utility routine to check if the InetAddress in a wildcard address.
351 * @return a {@code boolean} indicating if the Inetaddress is
352 * a wildcard address.
353 * @since 1.4
354 */
355 public boolean isAnyLocalAddress() {
356 return false;
357 }
358
359 /**
360 * Utility routine to check if the InetAddress is a loopback address.
361 *
362 * @return a {@code boolean} indicating if the InetAddress is
363 * a loopback address; or false otherwise.
364 * @since 1.4
365 */
366 public boolean isLoopbackAddress() {
367 return false;
368 }
369
370 /**
371 * Utility routine to check if the InetAddress is an link local address.
372 *
373 * @return a {@code boolean} indicating if the InetAddress is
374 * a link local address; or false if address is not a link local unicast address.
375 * @since 1.4
376 */
377 public boolean isLinkLocalAddress() {
378 return false;
379 }
380
381 /**
382 * Utility routine to check if the InetAddress is a site local address.
383 *
384 * @return a {@code boolean} indicating if the InetAddress is
385 * a site local address; or false if address is not a site local unicast address.
386 * @since 1.4
387 */
388 public boolean isSiteLocalAddress() {
389 return false;
390 }
391
392 /**
393 * Utility routine to check if the multicast address has global scope.
394 *
395 * @return a {@code boolean} indicating if the address has
396 * is a multicast address of global scope, false if it is not
397 * of global scope or it is not a multicast address
398 * @since 1.4
399 */
400 public boolean isMCGlobal() {
401 return false;
402 }
403
404 /**
405 * Utility routine to check if the multicast address has node scope.
406 *
407 * @return a {@code boolean} indicating if the address has
408 * is a multicast address of node-local scope, false if it is not
409 * of node-local scope or it is not a multicast address
410 * @since 1.4
411 */
412 public boolean isMCNodeLocal() {
413 return false;
414 }
415
416 /**
417 * Utility routine to check if the multicast address has link scope.
418 *
419 * @return a {@code boolean} indicating if the address has
420 * is a multicast address of link-local scope, false if it is not
421 * of link-local scope or it is not a multicast address
422 * @since 1.4
423 */
424 public boolean isMCLinkLocal() {
425 return false;
426 }
427
428 /**
429 * Utility routine to check if the multicast address has site scope.
430 *
431 * @return a {@code boolean} indicating if the address has
432 * is a multicast address of site-local scope, false if it is not
433 * of site-local scope or it is not a multicast address
434 * @since 1.4
435 */
436 public boolean isMCSiteLocal() {
437 return false;
438 }
439
440 /**
441 * Utility routine to check if the multicast address has organization scope.
442 *
443 * @return a {@code boolean} indicating if the address has
444 * is a multicast address of organization-local scope,
445 * false if it is not of organization-local scope
446 * or it is not a multicast address
447 * @since 1.4
448 */
449 public boolean isMCOrgLocal() {
450 return false;
451 }
452
453
454 /**
455 * Test whether that address is reachable. Best effort is made by the
456 * implementation to try to reach the host, but firewalls and server
457 * configuration may block requests resulting in a unreachable status
458 * while some specific ports may be accessible.
459 * A typical implementation will use ICMP ECHO REQUESTs if the
460 * privilege can be obtained, otherwise it will try to establish
461 * a TCP connection on port 7 (Echo) of the destination host.
462 * <p>
463 * The timeout value, in milliseconds, indicates the maximum amount of time
464 * the try should take. If the operation times out before getting an
465 * answer, the host is deemed unreachable. A negative value will result
466 * in an IllegalArgumentException being thrown.
467 *
468 * @param timeout the time, in milliseconds, before the call aborts
469 * @return a {@code boolean} indicating if the address is reachable.
470 * @throws IOException if a network error occurs
471 * @throws IllegalArgumentException if {@code timeout} is negative.
472 * @since 1.5
473 */
474 public boolean isReachable(int timeout) throws IOException {
475 return isReachable(null, 0 , timeout);
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 {@code network interface} and {@code ttl} parameters
488 * let the caller specify which network interface the test will go through
489 * and the maximum number of hops the packets should go through.
490 * A negative value for the {@code ttl} will result in an
491 * IllegalArgumentException being thrown.
492 * <p>
493 * The timeout value, in milliseconds, indicates the maximum amount of time
494 * the try should take. If the operation times out before getting an
495 * answer, the host is deemed unreachable. A negative value will result
496 * in an IllegalArgumentException being thrown.
497 *
498 * @param netif the NetworkInterface through which the
499 * test will be done, or null for any interface
500 * @param ttl the maximum numbers of hops to try or 0 for the
501 * default
502 * @param timeout the time, in milliseconds, before the call aborts
503 * @throws IllegalArgumentException if either {@code timeout}
504 * or {@code ttl} are negative.
505 * @return a {@code boolean}indicating if the address is reachable.
506 * @throws IOException if a network error occurs
507 * @since 1.5
508 */
509 public boolean isReachable(NetworkInterface netif, int ttl,
510 int timeout) throws IOException {
511 if (ttl < 0)
512 throw new IllegalArgumentException("ttl can't be negative");
513 if (timeout < 0)
514 throw new IllegalArgumentException("timeout can't be negative");
515
516 return impl.isReachable(this, timeout, netif, ttl);
517 }
518
519 /**
520 * Gets the host name for this IP address.
521 *
522 * <p>If this InetAddress was created with a host name,
523 * this host name will be remembered and returned;
524 * otherwise, a reverse name lookup will be performed
525 * and the result will be returned based on the system
526 * configured name lookup service. If a lookup of the name service
527 * is required, call
528 * {@link #getCanonicalHostName() getCanonicalHostName}.
529 *
530 * <p>If there is a security manager, its
531 * {@code checkConnect} method is first called
532 * with the hostname and {@code -1}
533 * as its arguments to see if the operation is allowed.
534 * If the operation is not allowed, it will return
535 * the textual representation of the IP address.
536 *
537 * @return the host name for this IP address, or if the operation
538 * is not allowed by the security check, the textual
539 * representation of the IP address.
540 *
541 * @see InetAddress#getCanonicalHostName
542 * @see SecurityManager#checkConnect
543 */
544 public String getHostName() {
545 return getHostName(true);
546 }
547
548 /**
549 * Returns the hostname for this address.
550 * If the host is equal to null, then this address refers to any
551 * of the local machine's available network addresses.
552 * this is package private so SocketPermission can make calls into
553 * here without a security check.
554 *
555 * <p>If there is a security manager, this method first
556 * calls its {@code checkConnect} method
557 * with the hostname and {@code -1}
558 * as its arguments to see if the calling code is allowed to know
559 * the hostname for this IP address, i.e., to connect to the host.
560 * If the operation is not allowed, it will return
561 * the textual representation of the IP address.
562 *
563 * @return the host name for this IP address, or if the operation
564 * is not allowed by the security check, the textual
565 * representation of the IP address.
566 *
567 * @param check make security check if true
568 *
569 * @see SecurityManager#checkConnect
570 */
571 String getHostName(boolean check) {
572 if (holder().getHostName() == null) {
573 holder().hostName = InetAddress.getHostFromNameService(this, check);
574 }
575 return holder().getHostName();
576 }
577
578 /**
579 * Gets the fully qualified domain name for this IP address.
580 * Best effort method, meaning we may not be able to return
581 * the FQDN depending on the underlying system configuration.
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 fully qualified domain name for this IP address,
592 * or if the operation is not allowed by the security check,
593 * the textual representation of the IP address.
594 *
595 * @see SecurityManager#checkConnect
596 *
597 * @since 1.4
598 */
599 public String getCanonicalHostName() {
600 if (canonicalHostName == null) {
601 canonicalHostName =
602 InetAddress.getHostFromNameService(this, true);
603 }
604 return canonicalHostName;
605 }
606
607 /**
608 * Returns the hostname for this address.
609 *
610 * <p>If there is a security manager, this method first
611 * calls its {@code checkConnect} method
612 * with the hostname and {@code -1}
613 * as its arguments to see if the calling code is allowed to know
614 * the hostname for this IP address, i.e., to connect to the host.
615 * If the operation is not allowed, it will return
616 * the textual representation of the IP address.
617 *
618 * @return the host name for this IP address, or if the operation
619 * is not allowed by the security check, the textual
620 * representation of the IP address.
621 *
622 * @param check make security check if true
623 *
624 * @see SecurityManager#checkConnect
625 */
626 private static String getHostFromNameService(InetAddress addr, boolean check) {
627 String host = null;
628 try {
629 // first lookup the hostname
630 host = nameService.getHostByAddr(addr.getAddress());
631
632 /* check to see if calling code is allowed to know
633 * the hostname for this IP address, ie, connect to the host
634 */
635 if (check) {
636 SecurityManager sec = System.getSecurityManager();
637 if (sec != null) {
638 sec.checkConnect(host, -1);
639 }
640 }
641
642 /* now get all the IP addresses for this hostname,
643 * and make sure one of them matches the original IP
644 * address. We do this to try and prevent spoofing.
645 */
646
647 InetAddress[] arr = InetAddress.getAllByName0(host, check);
648 boolean ok = false;
649
650 if(arr != null) {
651 for(int i = 0; !ok && i < arr.length; i++) {
652 ok = addr.equals(arr[i]);
653 }
654 }
655
656 //XXX: if it looks a spoof just return the address?
657 if (!ok) {
658 host = addr.getHostAddress();
659 return host;
660 }
661 } catch (SecurityException e) {
662 host = addr.getHostAddress();
663 } catch (UnknownHostException e) {
664 host = addr.getHostAddress();
665 // let next provider resolve the hostname
666 }
667 return host;
668 }
669
670 /**
671 * Returns the raw IP address of this {@code InetAddress}
672 * object. The result is in network byte order: the highest order
673 * byte of the address is in {@code getAddress()[0]}.
674 *
675 * @return the raw IP address of this object.
676 */
677 public byte[] getAddress() {
678 return null;
679 }
680
681 /**
682 * Returns the IP address string in textual presentation.
683 *
684 * @return the raw IP address in a string format.
685 * @since 1.0.2
686 */
687 public String getHostAddress() {
688 return null;
689 }
690
691 /**
692 * Returns a hashcode for this IP address.
693 *
694 * @return a hash code value for this IP address.
695 */
696 public int hashCode() {
697 return -1;
698 }
699
700 /**
701 * Compares this object against the specified object.
702 * The result is {@code true} if and only if the argument is
703 * not {@code null} and it represents the same IP address as
704 * this object.
705 * <p>
706 * Two instances of {@code InetAddress} represent the same IP
707 * address if the length of the byte arrays returned by
708 * {@code getAddress} is the same for both, and each of the
709 * array components is the same for the byte arrays.
710 *
711 * @param obj the object to compare against.
712 * @return {@code true} if the objects are the same;
713 * {@code false} otherwise.
714 * @see java.net.InetAddress#getAddress()
715 */
716 public boolean equals(Object obj) {
717 return false;
718 }
719
720 /**
721 * Converts this IP address to a {@code String}. The
722 * string returned is of the form: hostname / literal IP
723 * address.
724 *
725 * If the host name is unresolved, no reverse name service lookup
726 * is performed. The hostname part will be represented by an empty string.
727 *
728 * @return a string representation of this IP address.
729 */
730 public String toString() {
731 String hostName = holder().getHostName();
732 return Objects.toString(hostName, "")
733 + "/" + getHostAddress();
734 }
735
736 // mapping from host name to Addresses - either NameServiceAddresses (while
737 // still being looked-up by NameService(s)) or CachedAddresses when cached
738 private static final ConcurrentMap<String, Addresses> cache =
739 new ConcurrentHashMap<>();
740
741 // CachedAddresses that have to expire are kept ordered in this NavigableSet
742 // which is scanned on each access
743 private static final NavigableSet<CachedAddresses> expirySet =
744 new ConcurrentSkipListSet<>();
745
746 // common interface
747 private interface Addresses {
748 InetAddress[] get() throws UnknownHostException;
749 }
750
751 // a holder for cached addresses with required metadata
752 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> {
753 private static final AtomicLong seq = new AtomicLong();
754 final String host;
755 final InetAddress[] inetAddresses;
756 final long expiryTime; // time of expiry (in terms of System.nanoTime())
757 final long id = seq.incrementAndGet(); // each instance is unique
758
759 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) {
760 this.host = host;
761 this.inetAddresses = inetAddresses;
762 this.expiryTime = expiryTime;
763 }
764
765 @Override
766 public InetAddress[] get() throws UnknownHostException {
767 if (inetAddresses == null) {
768 throw new UnknownHostException(host);
769 }
770 return inetAddresses;
771 }
772
773 @Override
774 public int compareTo(CachedAddresses other) {
775 // natural order is expiry time -
776 // compare difference of expiry times rather than
777 // expiry times directly, to avoid possible overflow.
778 // (see System.nanoTime() recommendations...)
779 long diff = this.expiryTime - other.expiryTime;
780 if (diff < 0L) return -1;
781 if (diff > 0L) return 1;
782 // ties are broken using unique id
783 return Long.compare(this.id, other.id);
784 }
785 }
786
787 // a name service lookup based Addresses implementation which replaces itself
788 // in cache when the result is obtained
789 private static final class NameServiceAddresses implements Addresses {
790 private final String host;
791 private final InetAddress reqAddr;
792
793 NameServiceAddresses(String host, InetAddress reqAddr) {
794 this.host = host;
795 this.reqAddr = reqAddr;
796 }
797
798 @Override
799 public InetAddress[] get() throws UnknownHostException {
800 Addresses addresses;
801 // only one thread is doing lookup to name service
802 // for particular host at any time.
803 synchronized (this) {
804 // re-check that we are still us + re-install us if slot empty
805 addresses = cache.putIfAbsent(host, this);
806 if (addresses == null) {
807 // this can happen when we were replaced by CachedAddresses in
808 // some other thread, then CachedAddresses expired and were
809 // removed from cache while we were waiting for lock...
810 addresses = this;
811 }
812 // still us ?
813 if (addresses == this) {
814 // lookup name services
815 InetAddress[] inetAddresses;
816 UnknownHostException ex;
817 int cachePolicy;
818 try {
819 inetAddresses = getAddressesFromNameService(host, reqAddr);
820 ex = null;
821 cachePolicy = InetAddressCachePolicy.get();
822 } catch (UnknownHostException uhe) {
823 inetAddresses = null;
824 ex = uhe;
825 cachePolicy = InetAddressCachePolicy.getNegative();
826 }
827 // remove or replace us with cached addresses according to cachePolicy
828 if (cachePolicy == InetAddressCachePolicy.NEVER) {
829 cache.remove(host, this);
830 } else {
831 CachedAddresses cachedAddresses = new CachedAddresses(
832 host,
833 inetAddresses,
834 cachePolicy == InetAddressCachePolicy.FOREVER
835 ? 0L
836 // cachePolicy is in [s] - we need [ns]
837 : System.nanoTime() + 1000_000_000L * cachePolicy
838 );
839 if (cache.replace(host, this, cachedAddresses) &&
840 cachePolicy != InetAddressCachePolicy.FOREVER) {
841 // schedule expiry
842 expirySet.add(cachedAddresses);
843 }
844 }
845 if (inetAddresses == null) {
846 throw ex == null ? new UnknownHostException(host) : ex;
847 }
848 return inetAddresses;
849 }
850 // else addresses != this
851 }
852 // delegate to different addresses when we are already replaced
853 // but outside of synchronized block to avoid any chance of dead-locking
854 return addresses.get();
855 }
856 }
857
858 /**
859 * NameService provides host and address lookup service
860 *
861 * @since 9
862 */
863 private interface NameService {
864
865 /**
866 * Looks up a host mapping by name. Retrieves the IP addresses
867 * associated with a host.
868 *
869 * @param host the specified hostname
870 * @return an array of IP addresses for the given host name
871 * @throws UnknownHostException
872 * if no IP address for the {@code host} could be found
873 */
874 InetAddress[] lookupAllHostAddr(String host)
875 throws UnknownHostException;
876
877 /**
878 * Looks up the host corresponding to the given IP address.
879 *
880 * @param addr byte array representing an IP address
881 * @return {@code String} representing the host name mapping
882 * @throws UnknownHostException
883 * if no host found for the specified IP address
884 */
885 String getHostByAddr(byte[] addr) throws UnknownHostException;
886 }
887
888 /**
889 * The default NameService implementation, which delegates to the underlying
890 * OS network libraries to resolve host address mappings.
891 *
892 * @since 9
893 */
894 private static final class PlatformNameService implements NameService {
895
896 public InetAddress[] lookupAllHostAddr(String host)
897 throws UnknownHostException
898 {
899 return impl.lookupAllHostAddr(host);
900 }
901
902 public String getHostByAddr(byte[] addr) throws UnknownHostException {
903 return impl.getHostByAddr(addr);
904 }
905 }
906
907 /**
908 * A HostsFileNameService provides host address mappings by reading the
909 * entries in a hosts file, which is specified by the {@code
910 * jdk.net.hosts.file} system property.
911 *
912 * <p> The file format is that which corresponds to the /etc/hosts file
913 * IP Address host alias list.
914 *
915 * <p> When the file lookup is enabled it replaces the default NameService
916 * implementation.
917 *
918 * @since 9
919 */
920 private static final class HostsFileNameService implements NameService {
921
922 private final String hostsFile;
923
924 public HostsFileNameService (String hostsFileName) {
925 this.hostsFile = hostsFileName;
926 }
927
928 private String addrToString(byte addr[]) {
929 return Byte.toString(addr[0]) + "." + Byte.toString(addr[1]) + "."
930 + Byte.toString(addr[2]) + "." + Byte.toString(addr[3]);
931 }
932
933 /**
934 * Looks up the host name corresponding to the IP address provided.
935 * Searches the configured host file for a host name corresponding to
936 * the specified IP address.
937 *
938 * @param addr byte array representing an IP address
939 * @return {@code String} representing the host name mapping
940 * @throws UnknownHostException
941 * if no host found for the specified IP address
942 */
943 @Override
944 public String getHostByAddr(byte[] addr) throws UnknownHostException {
945 String hostEntry;
946 String host = null;
947
948 String addrString = addrToString(addr);
949 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
950 while (hostsFileScanner.hasNextLine()) {
951 hostEntry = hostsFileScanner.nextLine();
952 if (!hostEntry.startsWith("#")) {
953 hostEntry = removeComments(hostEntry);
954 if (hostEntry.contains(addrString)) {
955 host = extractHost(hostEntry, addrString);
956 if (host != null) {
957 break;
958 }
959 }
960 }
961 }
962 } catch (FileNotFoundException e) {
963 throw new UnknownHostException("Unable to resolve address "
964 + addrString + " as hosts file " + hostsFile
965 + " not found ");
966 }
967
968 if ((host == null) || (host.equals("")) || (host.equals(" "))) {
969 throw new UnknownHostException("Requested address "
970 + addrString
971 + " resolves to an invalid entry in hosts file "
972 + hostsFile);
973 }
974 return host;
975 }
976
977
978 /**
979 * Looks up a host mapping by name. Retrieves the IP addresses
980 * associated with a host.
981 *
982 * <p> Searches the configured hosts file for the addresses associated
983 * with with the specified host name.
984 *
985 * @param host the specified hostname
986 * @return array of IP addresses for the requested host
987 * @throws UnknownHostException
988 * if no IP address for the {@code host} could be found
989 */
990 @Override
991 public InetAddress[] lookupAllHostAddr(String host)
992 throws UnknownHostException
993 {
994 String hostEntry;
995 String addrStr;
996 InetAddress[] res;
997 byte addr[] = new byte[4];
998 ArrayList<InetAddress> inetAddresses = null;
999
1000 // lookup the file and create a list InetAddress for the specfied host
1001 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) {
1002 while (hostsFileScanner.hasNextLine()) {
1003 hostEntry = hostsFileScanner.nextLine();
1004 if (!hostEntry.startsWith("#")) {
1005 hostEntry = removeComments(hostEntry);
1006 if (hostEntry.contains(host)) {
1007 addrStr = extractHostAddr(hostEntry, host);
1008 if ((addrStr != null) && (!addrStr.equals(""))) {
1009 createAddressByteArray(addrStr, addr);
1010 if (inetAddresses == null) {
1011 inetAddresses = new ArrayList<>(1);
1012 }
1013 inetAddresses.add(InetAddress.getByAddress(host, addr));
1014 }
1015 }
1016 }
1017 }
1018 } catch (FileNotFoundException e) {
1019 throw new UnknownHostException("Unable to resolve host " + host
1020 + " as hosts file " + hostsFile + " not found ");
1021 }
1022
1023 if (inetAddresses != null) {
1024 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]);
1025 } else {
1026 throw new UnknownHostException("Unable to resolve host " + host
1027 + " in hosts file " + hostsFile);
1028 }
1029 return res;
1030 }
1031
1032 private String removeComments(String hostsEntry) {
1033 String filteredEntry = hostsEntry;
1034 int hashIndex;
1035
1036 if ((hashIndex = hostsEntry.indexOf("#")) != -1) {
1037 filteredEntry = hostsEntry.substring(0, hashIndex);
1038 }
1039 return filteredEntry;
1040 }
1041
1042 private void createAddressByteArray(String addrStr, byte[] addr) {
1043 String[] ipAddr = addrStr.split("\\.");
1044 for (int i = 0; i < 4; i++) {
1045 addr[i] = (byte) Integer.parseInt(ipAddr[i]);
1046 }
1047 }
1048
1049 /** Host to IP address mapping. */
1050 private String extractHostAddr(String hostEntry, String host) {
1051 String[] mapping = hostEntry.split("\\s+");
1052 String hostAddr = null;
1053
1054 if (mapping.length >= 2) {
1055 // look at the host aliases
1056 for (int i = 1; i < mapping.length; i++) {
1057 if (mapping[i].equalsIgnoreCase(host)) {
1058 hostAddr = mapping[0];
1059 }
1060 }
1061 }
1062 return hostAddr;
1063 }
1064
1065 /** IP Address to host mapping. Uses first host alias in list. */
1066 private String extractHost(String hostEntry, String addrString) {
1067 String[] mapping = hostEntry.split("\\s+");
1068 String host = null;
1069
1070 if (mapping.length >= 2) {
1071 if (mapping[0].equalsIgnoreCase(addrString)) {
1072 host = mapping[1];
1073 }
1074 }
1075 return host;
1076 }
1077 }
1078
1079 static final InetAddressImpl impl;
1080
1081 static {
1082 // create the impl
1083 impl = InetAddressImplFactory.create();
1084
1085 // create name service
1086 nameService = createNameService();
1087 }
1088
1089 /**
1090 * Creates an instance of the NameService interface based on the value of
1091 * the {@code jdk.net.hosts.file} system property.
1092 *
1093 * <p> The default NameService is the PlatformNameService, which typically
1094 * delegates name and address resolution calls to the underlying OS network
1095 * libraries.
1096 *
1097 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file}
1098 * system property is set. If the specified file doesn't exist, the name or
1099 * address lookup will result in an UnknownHostException. Thus, non existent
1100 * hosts file is handled as if the file is empty.
1101 *
1102 * @return a NameService
1103 */
1104 private static NameService createNameService() {
1105 String hostsFileName = AccessController
1106 .doPrivileged(new GetPropertyAction("jdk.net.hosts.file"));
1107
1108 if (hostsFileName != null) {
1109 return new HostsFileNameService(hostsFileName);
1110 } else {
1111 return new PlatformNameService();
1112 }
1113 }
1114
1115 /**
1116 * Creates an InetAddress based on the provided host name and IP address.
1117 * No name service is checked for the validity of the address.
1118 *
1119 * <p> The host name can either be a machine name, such as
1120 * "{@code java.sun.com}", or a textual representation of its IP
1121 * address.
1122 * <p> No validity checking is done on the host name either.
1123 *
1124 * <p> If addr specifies an IPv4 address an instance of Inet4Address
1125 * will be returned; otherwise, an instance of Inet6Address
1126 * will be returned.
1127 *
1128 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1129 * must be 16 bytes long
1130 *
1131 * @param host the specified host
1132 * @param addr the raw IP address in network byte order
1133 * @return an InetAddress object created from the raw IP address.
1134 * @exception UnknownHostException if IP address is of illegal length
1135 * @since 1.4
1136 */
1137 public static InetAddress getByAddress(String host, byte[] addr)
1138 throws UnknownHostException {
1139 if (host != null && host.length() > 0 && host.charAt(0) == '[') {
1140 if (host.charAt(host.length()-1) == ']') {
1141 host = host.substring(1, host.length() -1);
1142 }
1143 }
1144 if (addr != null) {
1145 if (addr.length == Inet4Address.INADDRSZ) {
1146 return new Inet4Address(host, addr);
1147 } else if (addr.length == Inet6Address.INADDRSZ) {
1148 byte[] newAddr
1149 = IPAddressUtil.convertFromIPv4MappedAddress(addr);
1150 if (newAddr != null) {
1151 return new Inet4Address(host, newAddr);
1152 } else {
1153 return new Inet6Address(host, addr);
1154 }
1155 }
1156 }
1157 throw new UnknownHostException("addr is of illegal length");
1158 }
1159
1160
1161 /**
1162 * Determines the IP address of a host, given the host's name.
1163 *
1164 * <p> The host name can either be a machine name, such as
1165 * "{@code java.sun.com}", or a textual representation of its
1166 * IP address. If a literal IP address is supplied, only the
1167 * validity of the address format is checked.
1168 *
1169 * <p> For {@code host} specified in literal IPv6 address,
1170 * either the form defined in RFC 2732 or the literal IPv6 address
1171 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also
1172 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6
1173 * scoped addresses.
1174 *
1175 * <p> If the host is {@code null} then an {@code InetAddress}
1176 * representing an address of the loopback interface is returned.
1177 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1178 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1179 * section 2.5.3. </p>
1180 *
1181 * @param host the specified host, or {@code null}.
1182 * @return an IP address for the given host name.
1183 * @exception UnknownHostException if no IP address for the
1184 * {@code host} could be found, or if a scope_id was specified
1185 * for a global IPv6 address.
1186 * @exception SecurityException if a security manager exists
1187 * and its checkConnect method doesn't allow the operation
1188 */
1189 public static InetAddress getByName(String host)
1190 throws UnknownHostException {
1191 return InetAddress.getAllByName(host)[0];
1192 }
1193
1194 // called from deployment cache manager
1195 private static InetAddress getByName(String host, InetAddress reqAddr)
1196 throws UnknownHostException {
1197 return InetAddress.getAllByName(host, reqAddr)[0];
1198 }
1199
1200 /**
1201 * Given the name of a host, returns an array of its IP addresses,
1202 * based on the configured name service on the system.
1203 *
1204 * <p> The host name can either be a machine name, such as
1205 * "{@code java.sun.com}", or a textual representation of its IP
1206 * address. If a literal IP address is supplied, only the
1207 * validity of the address format is checked.
1208 *
1209 * <p> For {@code host} specified in <i>literal IPv6 address</i>,
1210 * either the form defined in RFC 2732 or the literal IPv6 address
1211 * format defined in RFC 2373 is accepted. A literal IPv6 address may
1212 * also be qualified by appending a scoped zone identifier or scope_id.
1213 * The syntax and usage of scope_ids is described
1214 * <a href="Inet6Address.html#scoped">here</a>.
1215 * <p> If the host is {@code null} then an {@code InetAddress}
1216 * representing an address of the loopback interface is returned.
1217 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a>
1218 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a>
1219 * section 2.5.3. </p>
1220 *
1221 * <p> If there is a security manager and {@code host} is not
1222 * null and {@code host.length() } is not equal to zero, the
1223 * security manager's
1224 * {@code checkConnect} method is called
1225 * with the hostname and {@code -1}
1226 * as its arguments to see if the operation is allowed.
1227 *
1228 * @param host the name of the host, or {@code null}.
1229 * @return an array of all the IP addresses for a given host name.
1230 *
1231 * @exception UnknownHostException if no IP address for the
1232 * {@code host} could be found, or if a scope_id was specified
1233 * for a global IPv6 address.
1234 * @exception SecurityException if a security manager exists and its
1235 * {@code checkConnect} method doesn't allow the operation.
1236 *
1237 * @see SecurityManager#checkConnect
1238 */
1239 public static InetAddress[] getAllByName(String host)
1240 throws UnknownHostException {
1241 return getAllByName(host, null);
1242 }
1243
1244 private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
1245 throws UnknownHostException {
1246
1247 if (host == null || host.length() == 0) {
1248 InetAddress[] ret = new InetAddress[1];
1249 ret[0] = impl.loopbackAddress();
1250 return ret;
1251 }
1252
1253 boolean ipv6Expected = false;
1254 if (host.charAt(0) == '[') {
1255 // This is supposed to be an IPv6 literal
1256 if (host.length() > 2 && host.charAt(host.length()-1) == ']') {
1257 host = host.substring(1, host.length() -1);
1258 ipv6Expected = true;
1259 } else {
1260 // This was supposed to be a IPv6 address, but it's not!
1261 throw new UnknownHostException(host + ": invalid IPv6 address");
1262 }
1263 }
1264
1265 // if host is an IP address, we won't do further lookup
1266 if (Character.digit(host.charAt(0), 16) != -1
1267 || (host.charAt(0) == ':')) {
1268 byte[] addr = null;
1269 int numericZone = -1;
1270 String ifname = null;
1271 // see if it is IPv4 address
1272 addr = IPAddressUtil.textToNumericFormatV4(host);
1273 if (addr == null) {
1274 // This is supposed to be an IPv6 literal
1275 // Check if a numeric or string zone id is present
1276 int pos;
1277 if ((pos=host.indexOf ('%')) != -1) {
1278 numericZone = checkNumericZone (host);
1279 if (numericZone == -1) { /* remainder of string must be an ifname */
1280 ifname = host.substring (pos+1);
1281 }
1282 }
1283 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) {
1284 throw new UnknownHostException(host + ": invalid IPv6 address");
1285 }
1286 } else if (ipv6Expected) {
1287 // Means an IPv4 litteral between brackets!
1288 throw new UnknownHostException("["+host+"]");
1289 }
1290 InetAddress[] ret = new InetAddress[1];
1291 if(addr != null) {
1292 if (addr.length == Inet4Address.INADDRSZ) {
1293 ret[0] = new Inet4Address(null, addr);
1294 } else {
1295 if (ifname != null) {
1296 ret[0] = new Inet6Address(null, addr, ifname);
1297 } else {
1298 ret[0] = new Inet6Address(null, addr, numericZone);
1299 }
1300 }
1301 return ret;
1302 }
1303 } else if (ipv6Expected) {
1304 // We were expecting an IPv6 Litteral, but got something else
1305 throw new UnknownHostException("["+host+"]");
1306 }
1307 return getAllByName0(host, reqAddr, true, true);
1308 }
1309
1310 /**
1311 * Returns the loopback address.
1312 * <p>
1313 * The InetAddress returned will represent the IPv4
1314 * loopback address, 127.0.0.1, or the IPv6 loopback
1315 * address, ::1. The IPv4 loopback address returned
1316 * is only one of many in the form 127.*.*.*
1317 *
1318 * @return the InetAddress loopback instance.
1319 * @since 1.7
1320 */
1321 public static InetAddress getLoopbackAddress() {
1322 return impl.loopbackAddress();
1323 }
1324
1325
1326 /**
1327 * check if the literal address string has %nn appended
1328 * returns -1 if not, or the numeric value otherwise.
1329 *
1330 * %nn may also be a string that represents the displayName of
1331 * a currently available NetworkInterface.
1332 */
1333 private static int checkNumericZone (String s) throws UnknownHostException {
1334 int percent = s.indexOf ('%');
1335 int slen = s.length();
1336 int digit, zone=0;
1337 if (percent == -1) {
1338 return -1;
1339 }
1340 for (int i=percent+1; i<slen; i++) {
1341 char c = s.charAt(i);
1342 if (c == ']') {
1343 if (i == percent+1) {
1344 /* empty per-cent field */
1345 return -1;
1346 }
1347 break;
1348 }
1349 if ((digit = Character.digit (c, 10)) < 0) {
1350 return -1;
1351 }
1352 zone = (zone * 10) + digit;
1353 }
1354 return zone;
1355 }
1356
1357 private static InetAddress[] getAllByName0 (String host)
1358 throws UnknownHostException
1359 {
1360 return getAllByName0(host, true);
1361 }
1362
1363 /**
1364 * package private so SocketPermission can call it
1365 */
1366 static InetAddress[] getAllByName0 (String host, boolean check)
1367 throws UnknownHostException {
1368 return getAllByName0 (host, null, check, true);
1369 }
1370
1371 /**
1372 * Designated lookup method.
1373 *
1374 * @param host host name to look up
1375 * @param reqAddr requested address to be the 1st in returned array
1376 * @param check perform security check
1377 * @param useCache use cached value if not expired else always
1378 * perform name service lookup (and cache the result)
1379 * @return array of InetAddress(es)
1380 * @throws UnknownHostException if host name is not found
1381 */
1382 private static InetAddress[] getAllByName0(String host,
1383 InetAddress reqAddr,
1384 boolean check,
1385 boolean useCache)
1386 throws UnknownHostException {
1387
1388 /* If it gets here it is presumed to be a hostname */
1389
1390 /* make sure the connection to the host is allowed, before we
1391 * give out a hostname
1392 */
1393 if (check) {
1394 SecurityManager security = System.getSecurityManager();
1395 if (security != null) {
1396 security.checkConnect(host, -1);
1397 }
1398 }
1399
1400 // remove expired addresses from cache - expirySet keeps them ordered
1401 // by expiry time so we only need to iterate the prefix of the NavigableSet...
1402 long now = System.nanoTime();
1403 for (CachedAddresses caddrs : expirySet) {
1404 // compare difference of time instants rather than
1405 // time instants directly, to avoid possible overflow.
1406 // (see System.nanoTime() recommendations...)
1407 if ((caddrs.expiryTime - now) < 0L) {
1408 // ConcurrentSkipListSet uses weakly consistent iterator,
1409 // so removing while iterating is OK...
1410 if (expirySet.remove(caddrs)) {
1411 // ... remove from cache
1412 cache.remove(caddrs.host, caddrs);
1413 }
1414 } else {
1415 // we encountered 1st element that expires in future
1416 break;
1417 }
1418 }
1419
1420 // look-up or remove from cache
1421 Addresses addrs;
1422 if (useCache) {
1423 addrs = cache.get(host);
1424 } else {
1425 addrs = cache.remove(host);
1426 if (addrs != null) {
1427 if (addrs instanceof CachedAddresses) {
1428 // try removing from expirySet too if CachedAddresses
1429 expirySet.remove(addrs);
1430 }
1431 addrs = null;
1432 }
1433 }
1434
1435 if (addrs == null) {
1436 // create a NameServiceAddresses instance which will look up
1437 // the name service and install it within cache...
1438 Addresses oldAddrs = cache.putIfAbsent(
1439 host,
1440 addrs = new NameServiceAddresses(host, reqAddr)
1441 );
1442 if (oldAddrs != null) { // lost putIfAbsent race
1443 addrs = oldAddrs;
1444 }
1445 }
1446
1447 // ask Addresses to get an array of InetAddress(es) and clone it
1448 return addrs.get().clone();
1449 }
1450
1451 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr)
1452 throws UnknownHostException
1453 {
1454 InetAddress[] addresses = null;
1455 UnknownHostException ex = null;
1456
1457 try {
1458 addresses = nameService.lookupAllHostAddr(host);
1459 } catch (UnknownHostException uhe) {
1460 if (host.equalsIgnoreCase("localhost")) {
1461 addresses = new InetAddress[] { impl.loopbackAddress() };
1462 }
1463 else {
1464 ex = uhe;
1465 }
1466 }
1467
1468 if (addresses == null) {
1469 throw ex == null ? new UnknownHostException(host) : ex;
1470 }
1471
1472 // More to do?
1473 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) {
1474 // Find it?
1475 int i = 1;
1476 for (; i < addresses.length; i++) {
1477 if (addresses[i].equals(reqAddr)) {
1478 break;
1479 }
1480 }
1481 // Rotate
1482 if (i < addresses.length) {
1483 InetAddress tmp, tmp2 = reqAddr;
1484 for (int j = 0; j < i; j++) {
1485 tmp = addresses[j];
1486 addresses[j] = tmp2;
1487 tmp2 = tmp;
1488 }
1489 addresses[i] = tmp2;
1490 }
1491 }
1492
1493 return addresses;
1494 }
1495
1496 /**
1497 * Returns an {@code InetAddress} object given the raw IP address .
1498 * The argument is in network byte order: the highest order
1499 * byte of the address is in {@code getAddress()[0]}.
1500 *
1501 * <p> This method doesn't block, i.e. no reverse name service lookup
1502 * is performed.
1503 *
1504 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array
1505 * must be 16 bytes long
1506 *
1507 * @param addr the raw IP address in network byte order
1508 * @return an InetAddress object created from the raw IP address.
1509 * @exception UnknownHostException if IP address is of illegal length
1510 * @since 1.4
1511 */
1512 public static InetAddress getByAddress(byte[] addr)
1513 throws UnknownHostException {
1514 return getByAddress(null, addr);
1515 }
1516
1517 private static final class CachedLocalHost {
1518 final String host;
1519 final InetAddress addr;
1520 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s;
1521
1522 CachedLocalHost(String host, InetAddress addr) {
1523 this.host = host;
1524 this.addr = addr;
1525 }
1526 }
1527
1528 private static volatile CachedLocalHost cachedLocalHost;
1529
1530 /**
1531 * Returns the address of the local host. This is achieved by retrieving
1532 * the name of the host from the system, then resolving that name into
1533 * an {@code InetAddress}.
1534 *
1535 * <P>Note: The resolved address may be cached for a short period of time.
1536 * </P>
1537 *
1538 * <p>If there is a security manager, its
1539 * {@code checkConnect} method is called
1540 * with the local host name and {@code -1}
1541 * as its arguments to see if the operation is allowed.
1542 * If the operation is not allowed, an InetAddress representing
1543 * the loopback address is returned.
1544 *
1545 * @return the address of the local host.
1546 *
1547 * @exception UnknownHostException if the local host name could not
1548 * be resolved into an address.
1549 *
1550 * @see SecurityManager#checkConnect
1551 * @see java.net.InetAddress#getByName(java.lang.String)
1552 */
1553 public static InetAddress getLocalHost() throws UnknownHostException {
1554
1555 SecurityManager security = System.getSecurityManager();
1556 try {
1557 // is cached data still valid?
1558 CachedLocalHost clh = cachedLocalHost;
1559 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) {
1560 if (security != null) {
1561 security.checkConnect(clh.host, -1);
1562 }
1563 return clh.addr;
1564 }
1565
1566 String local = impl.getLocalHostName();
1567
1568 if (security != null) {
1569 security.checkConnect(local, -1);
1570 }
1571
1572 InetAddress localAddr;
1573 if (local.equals("localhost")) {
1574 // shortcut for "localhost" host name
1575 localAddr = impl.loopbackAddress();
1576 } else {
1577 // call getAllByName0 without security checks and
1578 // without using cached data
1579 try {
1580 localAddr = getAllByName0(local, null, false, false)[0];
1581 } catch (UnknownHostException uhe) {
1582 // Rethrow with a more informative error message.
1583 UnknownHostException uhe2 =
1584 new UnknownHostException(local + ": " +
1585 uhe.getMessage());
1586 uhe2.initCause(uhe);
1587 throw uhe2;
1588 }
1589 }
1590 cachedLocalHost = new CachedLocalHost(local, localAddr);
1591 return localAddr;
1592 } catch (java.lang.SecurityException e) {
1593 return impl.loopbackAddress();
1594 }
1595 }
1596
1597 /**
1598 * Perform class load-time initializations.
1599 */
1600 private static native void init();
1601
1602
1603 /*
1604 * Returns the InetAddress representing anyLocalAddress
1605 * (typically 0.0.0.0 or ::0)
1606 */
1607 static InetAddress anyLocalAddress() {
1608 return impl.anyLocalAddress();
1609 }
1610
1611 /*
1612 * Load and instantiate an underlying impl class
1613 */
1614 static InetAddressImpl loadImpl(String implName) {
1615 Object impl = null;
1616
1617 /*
1618 * Property "impl.prefix" will be prepended to the classname
1619 * of the implementation object we instantiate, to which we
1620 * delegate the real work (like native methods). This
1621 * property can vary across implementations of the java.
1622 * classes. The default is an empty String "".
1623 */
1624 String prefix = AccessController.doPrivileged(
1625 new GetPropertyAction("impl.prefix", ""));
1626 try {
1627 impl = Class.forName("java.net." + prefix + implName).newInstance();
1628 } catch (ClassNotFoundException e) {
1629 System.err.println("Class not found: java.net." + prefix +
1630 implName + ":\ncheck impl.prefix property " +
1631 "in your properties file.");
1632 } catch (InstantiationException e) {
1633 System.err.println("Could not instantiate: java.net." + prefix +
1634 implName + ":\ncheck impl.prefix property " +
1635 "in your properties file.");
1636 } catch (IllegalAccessException e) {
1637 System.err.println("Cannot access class: java.net." + prefix +
1638 implName + ":\ncheck impl.prefix property " +
1639 "in your properties file.");
1640 }
1641
1642 if (impl == null) {
1643 try {
1644 impl = Class.forName(implName).newInstance();
1645 } catch (Exception e) {
1646 throw new Error("System property impl.prefix incorrect");
1647 }
1648 }
1649
1650 return (InetAddressImpl) impl;
1651 }
1652
1653 private void readObjectNoData (ObjectInputStream s) throws
1654 IOException, ClassNotFoundException {
1655 if (getClass().getClassLoader() != null) {
1656 throw new SecurityException ("invalid address type");
1657 }
1658 }
1659
1660 private static final long FIELDS_OFFSET;
1661 private static final jdk.internal.misc.Unsafe UNSAFE;
1662
1663 static {
1664 try {
1665 jdk.internal.misc.Unsafe unsafe = jdk.internal.misc.Unsafe.getUnsafe();
1666 FIELDS_OFFSET = unsafe.objectFieldOffset(
1667 InetAddress.class.getDeclaredField("holder")
1668 );
1669 UNSAFE = unsafe;
1670 } catch (ReflectiveOperationException e) {
1671 throw new Error(e);
1672 }
1673 }
1674
1675 private void readObject (ObjectInputStream s) throws
1676 IOException, ClassNotFoundException {
1677 if (getClass().getClassLoader() != null) {
1678 throw new SecurityException ("invalid address type");
1679 }
1680 GetField gf = s.readFields();
1681 String host = (String)gf.get("hostName", null);
1682 int address= gf.get("address", 0);
1683 int family= gf.get("family", 0);
1684 InetAddressHolder h = new InetAddressHolder(host, address, family);
1685 UNSAFE.putObject(this, FIELDS_OFFSET, h);
1686 }
1687
1688 /* needed because the serializable fields no longer exist */
1689
1690 /**
1691 * @serialField hostName String
1692 * @serialField address int
1693 * @serialField family int
1694 */
1695 private static final ObjectStreamField[] serialPersistentFields = {
1696 new ObjectStreamField("hostName", String.class),
1697 new ObjectStreamField("address", int.class),
1698 new ObjectStreamField("family", int.class),
1699 };
1700
1701 private void writeObject (ObjectOutputStream s) throws
1702 IOException {
1703 if (getClass().getClassLoader() != null) {
1704 throw new SecurityException ("invalid address type");
1705 }
1706 PutField pf = s.putFields();
1707 pf.put("hostName", holder().getHostName());
1708 pf.put("address", holder().getAddress());
1709 pf.put("family", holder().getFamily());
1710 s.writeFields();
1711 }
1712 }
1713
1714 /*
1715 * Simple factory to create the impl
1716 */
1717 class InetAddressImplFactory {
1718
1719 static InetAddressImpl create() {
1720 return InetAddress.loadImpl(isIPv6Supported() ?
1721 "Inet6AddressImpl" : "Inet4AddressImpl");
1722 }
1723
1724 static native boolean isIPv6Supported();
1725 }