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