1 /* 2 * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.net; 27 28 import java.util.NavigableSet; 29 import java.util.ArrayList; 30 import java.util.Objects; 31 import java.util.Scanner; 32 import java.security.AccessController; 33 import java.io.File; 34 import java.io.FileNotFoundException; 35 import java.io.ObjectStreamException; 36 import java.io.ObjectStreamField; 37 import java.io.IOException; 38 import java.io.InvalidObjectException; 39 import java.io.ObjectInputStream; 40 import java.io.ObjectInputStream.GetField; 41 import java.io.ObjectOutputStream; 42 import java.io.ObjectOutputStream.PutField; 43 import java.lang.annotation.Native; 44 import java.util.concurrent.ConcurrentHashMap; 45 import java.util.concurrent.ConcurrentMap; 46 import java.util.concurrent.ConcurrentSkipListSet; 47 import java.util.concurrent.atomic.AtomicLong; 48 import java.util.Arrays; 49 50 import jdk.internal.access.JavaNetInetAddressAccess; 51 import jdk.internal.access.SharedSecrets; 52 import sun.security.action.*; 53 import sun.net.InetAddressCachePolicy; 54 import sun.net.util.IPAddressUtil; 55 56 /** 57 * This class represents an Internet Protocol (IP) address. 58 * 59 * <p> An IP address is either a 32-bit or 128-bit unsigned number 60 * used by IP, a lower-level protocol on which protocols like UDP and 61 * TCP are built. The IP address architecture is defined by <a 62 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790: 63 * Assigned Numbers</i></a>, <a 64 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918: 65 * Address Allocation for Private Internets</i></a>, <a 66 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365: 67 * Administratively Scoped IP Multicast</i></a>, and <a 68 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP 69 * Version 6 Addressing Architecture</i></a>. An instance of an 70 * InetAddress consists of an IP address and possibly its 71 * corresponding host name (depending on whether it is constructed 72 * with a host name or whether it has already done reverse host name 73 * resolution). 74 * 75 * <h2> Address types </h2> 76 * 77 * <table class="striped" style="margin-left:2em"> 78 * <caption style="display:none">Description of unicast and multicast address types</caption> 79 * <thead> 80 * <tr><th scope="col">Address Type</th><th scope="col">Description</th></tr> 81 * </thead> 82 * <tbody> 83 * <tr><th scope="row" style="vertical-align:top">unicast</th> 84 * <td>An identifier for a single interface. A packet sent to 85 * a unicast address is delivered to the interface identified by 86 * that address. 87 * 88 * <p> The Unspecified Address -- Also called anylocal or wildcard 89 * address. It must never be assigned to any node. It indicates the 90 * absence of an address. One example of its use is as the target of 91 * bind, which allows a server to accept a client connection on any 92 * interface, in case the server host has multiple interfaces. 93 * 94 * <p> The <i>unspecified</i> address must not be used as 95 * the destination address of an IP packet. 96 * 97 * <p> The <i>Loopback</i> Addresses -- This is the address 98 * assigned to the loopback interface. Anything sent to this 99 * IP address loops around and becomes IP input on the local 100 * host. This address is often used when testing a 101 * client.</td></tr> 102 * <tr><th scope="row" style="vertical-align:top">multicast</th> 103 * <td>An identifier for a set of interfaces (typically belonging 104 * to different nodes). A packet sent to a multicast address is 105 * delivered to all interfaces identified by that address.</td></tr> 106 * </tbody> 107 * </table> 108 * 109 * <h3> IP address scope </h3> 110 * 111 * <p> <i>Link-local</i> addresses are designed to be used for addressing 112 * on a single link for purposes such as auto-address configuration, 113 * neighbor discovery, or when no routers are present. 114 * 115 * <p> <i>Site-local</i> addresses are designed to be used for addressing 116 * inside of a site without the need for a global prefix. 117 * 118 * <p> <i>Global</i> addresses are unique across the internet. 119 * 120 * <h3> Textual representation of IP addresses </h3> 121 * 122 * The textual representation of an IP address is address family specific. 123 * 124 * <p> 125 * 126 * For IPv4 address format, please refer to <A 127 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6 128 * address format, please refer to <A 129 * HREF="Inet6Address.html#format">Inet6Address#format</A>. 130 * 131 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of 132 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P> 133 * 134 * <h3> Host Name Resolution </h3> 135 * 136 * Host name-to-IP address <i>resolution</i> is accomplished through 137 * the use of a combination of local machine configuration information 138 * and network naming services such as the Domain Name System (DNS) 139 * and Network Information Service(NIS). The particular naming 140 * services(s) being used is by default the local machine configured 141 * one. For any host name, its corresponding IP address is returned. 142 * 143 * <p> <i>Reverse name resolution</i> means that for any IP address, 144 * the host associated with the IP address is returned. 145 * 146 * <p> The InetAddress class provides methods to resolve host names to 147 * their IP addresses and vice versa. 148 * 149 * <h3> InetAddress Caching </h3> 150 * 151 * The InetAddress class has a cache to store successful as well as 152 * unsuccessful host name resolutions. 153 * 154 * <p> By default, when a security manager is installed, in order to 155 * protect against DNS spoofing attacks, 156 * the result of positive host name resolutions are 157 * cached forever. When a security manager is not installed, the default 158 * behavior is to cache entries for a finite (implementation dependent) 159 * period of time. The result of unsuccessful host 160 * name resolution is cached for a very short period of time (10 161 * seconds) to improve performance. 162 * 163 * <p> If the default behavior is not desired, then a Java security property 164 * can be set to a different Time-to-live (TTL) value for positive 165 * caching. Likewise, a system admin can configure a different 166 * negative caching TTL value when needed. 167 * 168 * <p> Two Java security properties control the TTL values used for 169 * positive and negative host name resolution caching: 170 * 171 * <dl style="margin-left:2em"> 172 * <dt><b>networkaddress.cache.ttl</b></dt> 173 * <dd>Indicates the caching policy for successful name lookups from 174 * the name service. The value is specified as an integer to indicate 175 * the number of seconds to cache the successful lookup. The default 176 * setting is to cache for an implementation specific period of time. 177 * <p> 178 * A value of -1 indicates "cache forever". 179 * </dd> 180 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt> 181 * <dd>Indicates the caching policy for un-successful name lookups 182 * from the name service. The value is specified as an integer to 183 * indicate the number of seconds to cache the failure for 184 * un-successful lookups. 185 * <p> 186 * A value of 0 indicates "never cache". 187 * A value of -1 indicates "cache forever". 188 * </dd> 189 * </dl> 190 * 191 * @author Chris Warth 192 * @see java.net.InetAddress#getByAddress(byte[]) 193 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[]) 194 * @see java.net.InetAddress#getAllByName(java.lang.String) 195 * @see java.net.InetAddress#getByName(java.lang.String) 196 * @see java.net.InetAddress#getLocalHost() 197 * @since 1.0 198 */ 199 public 200 class InetAddress implements java.io.Serializable { 201 202 @Native static final int PREFER_IPV4_VALUE = 0; 203 @Native static final int PREFER_IPV6_VALUE = 1; 204 @Native static final int PREFER_SYSTEM_VALUE = 2; 205 206 /** 207 * Specify the address family: Internet Protocol, Version 4 208 * @since 1.4 209 */ 210 @Native static final int IPv4 = 1; 211 212 /** 213 * Specify the address family: Internet Protocol, Version 6 214 * @since 1.4 215 */ 216 @Native static final int IPv6 = 2; 217 218 /* Specify address family preference */ 219 static transient final int preferIPv6Address; 220 221 static class InetAddressHolder { 222 /** 223 * Reserve the original application specified hostname. 224 * 225 * The original hostname is useful for domain-based endpoint 226 * identification (see RFC 2818 and RFC 6125). If an address 227 * was created with a raw IP address, a reverse name lookup 228 * may introduce endpoint identification security issue via 229 * DNS forging. 230 * 231 * Oracle JSSE provider is using this original hostname, via 232 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification. 233 * 234 * Note: May define a new public method in the future if necessary. 235 */ 236 String originalHostName; 237 238 InetAddressHolder() {} 239 240 InetAddressHolder(String hostName, int address, int family) { 241 this.originalHostName = hostName; 242 this.hostName = hostName; 243 this.address = address; 244 this.family = family; 245 } 246 247 void init(String hostName, int family) { 248 this.originalHostName = hostName; 249 this.hostName = hostName; 250 if (family != -1) { 251 this.family = family; 252 } 253 } 254 255 String hostName; 256 257 String getHostName() { 258 return hostName; 259 } 260 261 String getOriginalHostName() { 262 return originalHostName; 263 } 264 265 /** 266 * Holds a 32-bit IPv4 address. 267 */ 268 int address; 269 270 int getAddress() { 271 return address; 272 } 273 274 /** 275 * Specifies the address family type, for instance, '1' for IPv4 276 * addresses, and '2' for IPv6 addresses. 277 */ 278 int family; 279 280 int getFamily() { 281 return family; 282 } 283 } 284 285 /* Used to store the serializable fields of InetAddress */ 286 final transient InetAddressHolder holder; 287 288 InetAddressHolder holder() { 289 return holder; 290 } 291 292 /* Used to store the name service provider */ 293 private static transient NameService nameService; 294 295 /** 296 * Used to store the best available hostname. 297 * Lazily initialized via a data race; safe because Strings are immutable. 298 */ 299 private transient String canonicalHostName = null; 300 301 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 302 private static final long serialVersionUID = 3286316764910316507L; 303 304 /* 305 * Load net library into runtime, and perform initializations. 306 */ 307 static { 308 String str = GetPropertyAction.privilegedGetProperty("java.net.preferIPv6Addresses"); 309 if (str == null) { 310 preferIPv6Address = PREFER_IPV4_VALUE; 311 } else if (str.equalsIgnoreCase("true")) { 312 preferIPv6Address = PREFER_IPV6_VALUE; 313 } else if (str.equalsIgnoreCase("false")) { 314 preferIPv6Address = PREFER_IPV4_VALUE; 315 } else if (str.equalsIgnoreCase("system")) { 316 preferIPv6Address = PREFER_SYSTEM_VALUE; 317 } else { 318 preferIPv6Address = PREFER_IPV4_VALUE; 319 } 320 jdk.internal.access.SharedSecrets.getJavaLangAccess() 321 .loadLibrary(InetAddress.class, "net"); 322 SharedSecrets.setJavaNetInetAddressAccess( 323 new JavaNetInetAddressAccess() { 324 public String getOriginalHostName(InetAddress ia) { 325 return ia.holder.getOriginalHostName(); 326 } 327 328 public InetAddress getByName(String hostName, 329 InetAddress hostAddress) 330 throws UnknownHostException 331 { 332 return InetAddress.getByName(hostName, hostAddress); 333 } 334 } 335 ); 336 init(); 337 } 338 339 /** 340 * Constructor for the Socket.accept() method. 341 * This creates an empty InetAddress, which is filled in by 342 * the accept() method. This InetAddress, however, is not 343 * put in the address cache, since it is not created by name. 344 */ 345 InetAddress() { 346 holder = new InetAddressHolder(); 347 } 348 349 /** 350 * Replaces the de-serialized object with an Inet4Address object. 351 * 352 * @return the alternate object to the de-serialized object. 353 * 354 * @throws ObjectStreamException if a new object replacing this 355 * object could not be created 356 */ 357 private Object readResolve() throws ObjectStreamException { 358 // will replace the deserialized 'this' object 359 return new Inet4Address(holder().getHostName(), holder().getAddress()); 360 } 361 362 /** 363 * Utility routine to check if the InetAddress is an 364 * IP multicast address. 365 * @return a {@code boolean} indicating if the InetAddress is 366 * an IP multicast address 367 * @since 1.1 368 */ 369 public boolean isMulticastAddress() { 370 return false; 371 } 372 373 /** 374 * Utility routine to check if the InetAddress is a wildcard address. 375 * @return a {@code boolean} indicating if the InetAddress is 376 * a wildcard address. 377 * @since 1.4 378 */ 379 public boolean isAnyLocalAddress() { 380 return false; 381 } 382 383 /** 384 * Utility routine to check if the InetAddress is a loopback address. 385 * 386 * @return a {@code boolean} indicating if the InetAddress is 387 * a loopback address; or false otherwise. 388 * @since 1.4 389 */ 390 public boolean isLoopbackAddress() { 391 return false; 392 } 393 394 /** 395 * Utility routine to check if the InetAddress is an link local address. 396 * 397 * @return a {@code boolean} indicating if the InetAddress is 398 * a link local address; or false if address is not a link local unicast address. 399 * @since 1.4 400 */ 401 public boolean isLinkLocalAddress() { 402 return false; 403 } 404 405 /** 406 * Utility routine to check if the InetAddress is a site local address. 407 * 408 * @return a {@code boolean} indicating if the InetAddress is 409 * a site local address; or false if address is not a site local unicast address. 410 * @since 1.4 411 */ 412 public boolean isSiteLocalAddress() { 413 return false; 414 } 415 416 /** 417 * Utility routine to check if the multicast address has global scope. 418 * 419 * @return a {@code boolean} indicating if the address has 420 * is a multicast address of global scope, false if it is not 421 * of global scope or it is not a multicast address 422 * @since 1.4 423 */ 424 public boolean isMCGlobal() { 425 return false; 426 } 427 428 /** 429 * Utility routine to check if the multicast address has node scope. 430 * 431 * @return a {@code boolean} indicating if the address has 432 * is a multicast address of node-local scope, false if it is not 433 * of node-local scope or it is not a multicast address 434 * @since 1.4 435 */ 436 public boolean isMCNodeLocal() { 437 return false; 438 } 439 440 /** 441 * Utility routine to check if the multicast address has link scope. 442 * 443 * @return a {@code boolean} indicating if the address has 444 * is a multicast address of link-local scope, false if it is not 445 * of link-local scope or it is not a multicast address 446 * @since 1.4 447 */ 448 public boolean isMCLinkLocal() { 449 return false; 450 } 451 452 /** 453 * Utility routine to check if the multicast address has site scope. 454 * 455 * @return a {@code boolean} indicating if the address has 456 * is a multicast address of site-local scope, false if it is not 457 * of site-local scope or it is not a multicast address 458 * @since 1.4 459 */ 460 public boolean isMCSiteLocal() { 461 return false; 462 } 463 464 /** 465 * Utility routine to check if the multicast address has organization scope. 466 * 467 * @return a {@code boolean} indicating if the address has 468 * is a multicast address of organization-local scope, 469 * false if it is not of organization-local scope 470 * or it is not a multicast address 471 * @since 1.4 472 */ 473 public boolean isMCOrgLocal() { 474 return false; 475 } 476 477 478 /** 479 * Test whether that address is reachable. Best effort is made by the 480 * implementation to try to reach the host, but firewalls and server 481 * configuration may block requests resulting in a unreachable status 482 * while some specific ports may be accessible. 483 * A typical implementation will use ICMP ECHO REQUESTs if the 484 * privilege can be obtained, otherwise it will try to establish 485 * a TCP connection on port 7 (Echo) of the destination host. 486 * <p> 487 * The timeout value, in milliseconds, indicates the maximum amount of time 488 * the try should take. If the operation times out before getting an 489 * answer, the host is deemed unreachable. A negative value will result 490 * in an IllegalArgumentException being thrown. 491 * 492 * @param timeout the time, in milliseconds, before the call aborts 493 * @return a {@code boolean} indicating if the address is reachable. 494 * @throws IOException if a network error occurs 495 * @throws IllegalArgumentException if {@code timeout} is negative. 496 * @since 1.5 497 */ 498 public boolean isReachable(int timeout) throws IOException { 499 return isReachable(null, 0 , timeout); 500 } 501 502 /** 503 * Test whether that address is reachable. Best effort is made by the 504 * implementation to try to reach the host, but firewalls and server 505 * configuration may block requests resulting in a unreachable status 506 * while some specific ports may be accessible. 507 * A typical implementation will use ICMP ECHO REQUESTs if the 508 * privilege can be obtained, otherwise it will try to establish 509 * a TCP connection on port 7 (Echo) of the destination host. 510 * <p> 511 * The {@code network interface} and {@code ttl} parameters 512 * let the caller specify which network interface the test will go through 513 * and the maximum number of hops the packets should go through. 514 * A negative value for the {@code ttl} will result in an 515 * IllegalArgumentException being thrown. 516 * <p> 517 * The timeout value, in milliseconds, indicates the maximum amount of time 518 * the try should take. If the operation times out before getting an 519 * answer, the host is deemed unreachable. A negative value will result 520 * in an IllegalArgumentException being thrown. 521 * 522 * @param netif the NetworkInterface through which the 523 * test will be done, or null for any interface 524 * @param ttl the maximum numbers of hops to try or 0 for the 525 * default 526 * @param timeout the time, in milliseconds, before the call aborts 527 * @throws IllegalArgumentException if either {@code timeout} 528 * or {@code ttl} are negative. 529 * @return a {@code boolean} indicating if the address is reachable. 530 * @throws IOException if a network error occurs 531 * @since 1.5 532 */ 533 public boolean isReachable(NetworkInterface netif, int ttl, 534 int timeout) throws IOException { 535 if (ttl < 0) 536 throw new IllegalArgumentException("ttl can't be negative"); 537 if (timeout < 0) 538 throw new IllegalArgumentException("timeout can't be negative"); 539 540 return impl.isReachable(this, timeout, netif, ttl); 541 } 542 543 /** 544 * Gets the host name for this IP address. 545 * 546 * <p>If this InetAddress was created with a host name, 547 * this host name will be remembered and returned; 548 * otherwise, a reverse name lookup will be performed 549 * and the result will be returned based on the system 550 * configured name lookup service. If a lookup of the name service 551 * is required, call 552 * {@link #getCanonicalHostName() getCanonicalHostName}. 553 * 554 * <p>If there is a security manager, its 555 * {@code checkConnect} method is first called 556 * with the hostname and {@code -1} 557 * as its arguments to see if the operation is allowed. 558 * If the operation is not allowed, it will return 559 * the textual representation of the IP address. 560 * 561 * @return the host name for this IP address, or if the operation 562 * is not allowed by the security check, the textual 563 * representation of the IP address. 564 * 565 * @see InetAddress#getCanonicalHostName 566 * @see SecurityManager#checkConnect 567 */ 568 public String getHostName() { 569 return getHostName(true); 570 } 571 572 /** 573 * Returns the hostname for this address. 574 * If the host is equal to null, then this address refers to any 575 * of the local machine's available network addresses. 576 * this is package private so SocketPermission can make calls into 577 * here without a security check. 578 * 579 * <p>If there is a security manager, this method first 580 * calls its {@code checkConnect} method 581 * with the hostname and {@code -1} 582 * as its arguments to see if the calling code is allowed to know 583 * the hostname for this IP address, i.e., to connect to the host. 584 * If the operation is not allowed, it will return 585 * the textual representation of the IP address. 586 * 587 * @return the host name for this IP address, or if the operation 588 * is not allowed by the security check, the textual 589 * representation of the IP address. 590 * 591 * @param check make security check if true 592 * 593 * @see SecurityManager#checkConnect 594 */ 595 String getHostName(boolean check) { 596 if (holder().getHostName() == null) { 597 holder().hostName = InetAddress.getHostFromNameService(this, check); 598 } 599 return holder().getHostName(); 600 } 601 602 /** 603 * Gets the fully qualified domain name for this IP address. 604 * Best effort method, meaning we may not be able to return 605 * the FQDN depending on the underlying system configuration. 606 * 607 * <p>If there is a security manager, this method first 608 * calls its {@code checkConnect} method 609 * with the hostname and {@code -1} 610 * as its arguments to see if the calling code is allowed to know 611 * the hostname for this IP address, i.e., to connect to the host. 612 * If the operation is not allowed, it will return 613 * the textual representation of the IP address. 614 * 615 * @return the fully qualified domain name for this IP address, 616 * or if the operation is not allowed by the security check, 617 * the textual representation of the IP address. 618 * 619 * @see SecurityManager#checkConnect 620 * 621 * @since 1.4 622 */ 623 public String getCanonicalHostName() { 624 String value = canonicalHostName; 625 if (value == null) 626 canonicalHostName = value = 627 InetAddress.getHostFromNameService(this, true); 628 return value; 629 } 630 631 /** 632 * Returns the hostname for this address. 633 * 634 * <p>If there is a security manager, this method first 635 * calls its {@code checkConnect} method 636 * with the hostname and {@code -1} 637 * as its arguments to see if the calling code is allowed to know 638 * the hostname for this IP address, i.e., to connect to the host. 639 * If the operation is not allowed, it will return 640 * the textual representation of the IP address. 641 * 642 * @return the host name for this IP address, or if the operation 643 * is not allowed by the security check, the textual 644 * representation of the IP address. 645 * 646 * @param check make security check if true 647 * 648 * @see SecurityManager#checkConnect 649 */ 650 private static String getHostFromNameService(InetAddress addr, boolean check) { 651 String host = null; 652 try { 653 // first lookup the hostname 654 host = nameService.getHostByAddr(addr.getAddress()); 655 656 /* check to see if calling code is allowed to know 657 * the hostname for this IP address, ie, connect to the host 658 */ 659 if (check) { 660 SecurityManager sec = System.getSecurityManager(); 661 if (sec != null) { 662 sec.checkConnect(host, -1); 663 } 664 } 665 666 /* now get all the IP addresses for this hostname, 667 * and make sure one of them matches the original IP 668 * address. We do this to try and prevent spoofing. 669 */ 670 671 InetAddress[] arr = InetAddress.getAllByName0(host, check); 672 boolean ok = false; 673 674 if(arr != null) { 675 for(int i = 0; !ok && i < arr.length; i++) { 676 ok = addr.equals(arr[i]); 677 } 678 } 679 680 //XXX: if it looks a spoof just return the address? 681 if (!ok) { 682 host = addr.getHostAddress(); 683 return host; 684 } 685 } catch (SecurityException e) { 686 host = addr.getHostAddress(); 687 } catch (UnknownHostException e) { 688 host = addr.getHostAddress(); 689 // let next provider resolve the hostname 690 } 691 return host; 692 } 693 694 /** 695 * Returns the raw IP address of this {@code InetAddress} 696 * object. The result is in network byte order: the highest order 697 * byte of the address is in {@code getAddress()[0]}. 698 * 699 * @return the raw IP address of this object. 700 */ 701 public byte[] getAddress() { 702 return null; 703 } 704 705 /** 706 * Returns the IP address string in textual presentation. 707 * 708 * @return the raw IP address in a string format. 709 * @since 1.0.2 710 */ 711 public String getHostAddress() { 712 return null; 713 } 714 715 /** 716 * Returns a hashcode for this IP address. 717 * 718 * @return a hash code value for this IP address. 719 */ 720 public int hashCode() { 721 return -1; 722 } 723 724 /** 725 * Compares this object against the specified object. 726 * The result is {@code true} if and only if the argument is 727 * not {@code null} and it represents the same IP address as 728 * this object. 729 * <p> 730 * Two instances of {@code InetAddress} represent the same IP 731 * address if the length of the byte arrays returned by 732 * {@code getAddress} is the same for both, and each of the 733 * array components is the same for the byte arrays. 734 * 735 * @param obj the object to compare against. 736 * @return {@code true} if the objects are the same; 737 * {@code false} otherwise. 738 * @see java.net.InetAddress#getAddress() 739 */ 740 public boolean equals(Object obj) { 741 return false; 742 } 743 744 /** 745 * Converts this IP address to a {@code String}. The 746 * string returned is of the form: hostname / literal IP 747 * address. 748 * 749 * If the host name is unresolved, no reverse name service lookup 750 * is performed. The hostname part will be represented by an empty string. 751 * 752 * @return a string representation of this IP address. 753 */ 754 public String toString() { 755 String hostName = holder().getHostName(); 756 return Objects.toString(hostName, "") 757 + "/" + getHostAddress(); 758 } 759 760 // mapping from host name to Addresses - either NameServiceAddresses (while 761 // still being looked-up by NameService(s)) or CachedAddresses when cached 762 private static final ConcurrentMap<String, Addresses> cache = 763 new ConcurrentHashMap<>(); 764 765 // CachedAddresses that have to expire are kept ordered in this NavigableSet 766 // which is scanned on each access 767 private static final NavigableSet<CachedAddresses> expirySet = 768 new ConcurrentSkipListSet<>(); 769 770 // common interface 771 private interface Addresses { 772 InetAddress[] get() throws UnknownHostException; 773 } 774 775 // a holder for cached addresses with required metadata 776 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> { 777 private static final AtomicLong seq = new AtomicLong(); 778 final String host; 779 final InetAddress[] inetAddresses; 780 final long expiryTime; // time of expiry (in terms of System.nanoTime()) 781 final long id = seq.incrementAndGet(); // each instance is unique 782 783 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) { 784 this.host = host; 785 this.inetAddresses = inetAddresses; 786 this.expiryTime = expiryTime; 787 } 788 789 @Override 790 public InetAddress[] get() throws UnknownHostException { 791 if (inetAddresses == null) { 792 throw new UnknownHostException(host); 793 } 794 return inetAddresses; 795 } 796 797 @Override 798 public int compareTo(CachedAddresses other) { 799 // natural order is expiry time - 800 // compare difference of expiry times rather than 801 // expiry times directly, to avoid possible overflow. 802 // (see System.nanoTime() recommendations...) 803 long diff = this.expiryTime - other.expiryTime; 804 if (diff < 0L) return -1; 805 if (diff > 0L) return 1; 806 // ties are broken using unique id 807 return Long.compare(this.id, other.id); 808 } 809 } 810 811 // a name service lookup based Addresses implementation which replaces itself 812 // in cache when the result is obtained 813 private static final class NameServiceAddresses implements Addresses { 814 private final String host; 815 private final InetAddress reqAddr; 816 817 NameServiceAddresses(String host, InetAddress reqAddr) { 818 this.host = host; 819 this.reqAddr = reqAddr; 820 } 821 822 @Override 823 public InetAddress[] get() throws UnknownHostException { 824 Addresses addresses; 825 // only one thread is doing lookup to name service 826 // for particular host at any time. 827 synchronized (this) { 828 // re-check that we are still us + re-install us if slot empty 829 addresses = cache.putIfAbsent(host, this); 830 if (addresses == null) { 831 // this can happen when we were replaced by CachedAddresses in 832 // some other thread, then CachedAddresses expired and were 833 // removed from cache while we were waiting for lock... 834 addresses = this; 835 } 836 // still us ? 837 if (addresses == this) { 838 // lookup name services 839 InetAddress[] inetAddresses; 840 UnknownHostException ex; 841 int cachePolicy; 842 try { 843 inetAddresses = getAddressesFromNameService(host, reqAddr); 844 ex = null; 845 cachePolicy = InetAddressCachePolicy.get(); 846 } catch (UnknownHostException uhe) { 847 inetAddresses = null; 848 ex = uhe; 849 cachePolicy = InetAddressCachePolicy.getNegative(); 850 } 851 // remove or replace us with cached addresses according to cachePolicy 852 if (cachePolicy == InetAddressCachePolicy.NEVER) { 853 cache.remove(host, this); 854 } else { 855 CachedAddresses cachedAddresses = new CachedAddresses( 856 host, 857 inetAddresses, 858 cachePolicy == InetAddressCachePolicy.FOREVER 859 ? 0L 860 // cachePolicy is in [s] - we need [ns] 861 : System.nanoTime() + 1000_000_000L * cachePolicy 862 ); 863 if (cache.replace(host, this, cachedAddresses) && 864 cachePolicy != InetAddressCachePolicy.FOREVER) { 865 // schedule expiry 866 expirySet.add(cachedAddresses); 867 } 868 } 869 if (inetAddresses == null) { 870 throw ex == null ? new UnknownHostException(host) : ex; 871 } 872 return inetAddresses; 873 } 874 // else addresses != this 875 } 876 // delegate to different addresses when we are already replaced 877 // but outside of synchronized block to avoid any chance of dead-locking 878 return addresses.get(); 879 } 880 } 881 882 /** 883 * NameService provides host and address lookup service 884 * 885 * @since 9 886 */ 887 private interface NameService { 888 889 /** 890 * Lookup a host mapping by name. Retrieve the IP addresses 891 * associated with a host 892 * 893 * @param host the specified hostname 894 * @return array of IP addresses for the requested host 895 * @throws UnknownHostException 896 * if no IP address for the {@code host} could be found 897 */ 898 InetAddress[] lookupAllHostAddr(String host) 899 throws UnknownHostException; 900 901 /** 902 * Lookup the host corresponding to the IP address provided 903 * 904 * @param addr byte array representing an IP address 905 * @return {@code String} representing the host name mapping 906 * @throws UnknownHostException 907 * if no host found for the specified IP address 908 */ 909 String getHostByAddr(byte[] addr) throws UnknownHostException; 910 911 } 912 913 /** 914 * The default NameService implementation, which delegates to the underlying 915 * OS network libraries to resolve host address mappings. 916 * 917 * @since 9 918 */ 919 private static final class PlatformNameService implements NameService { 920 921 public InetAddress[] lookupAllHostAddr(String host) 922 throws UnknownHostException 923 { 924 return impl.lookupAllHostAddr(host); 925 } 926 927 public String getHostByAddr(byte[] addr) 928 throws UnknownHostException 929 { 930 return impl.getHostByAddr(addr); 931 } 932 } 933 934 /** 935 * The HostsFileNameService provides host address mapping 936 * by reading the entries in a hosts file, which is specified by 937 * {@code jdk.net.hosts.file} system property 938 * 939 * <p>The file format is that which corresponds with the /etc/hosts file 940 * IP Address host alias list. 941 * 942 * <p>When the file lookup is enabled it replaces the default NameService 943 * implementation 944 * 945 * @since 9 946 */ 947 private static final class HostsFileNameService implements NameService { 948 949 private final String hostsFile; 950 951 public HostsFileNameService (String hostsFileName) { 952 this.hostsFile = hostsFileName; 953 } 954 955 private String addrToString(byte addr[]) { 956 String stringifiedAddress = null; 957 958 if (addr.length == Inet4Address.INADDRSZ) { 959 stringifiedAddress = Inet4Address.numericToTextFormat(addr); 960 } else { // treat as an IPV6 jobby 961 byte[] newAddr 962 = IPAddressUtil.convertFromIPv4MappedAddress(addr); 963 if (newAddr != null) { 964 stringifiedAddress = Inet4Address.numericToTextFormat(addr); 965 } else { 966 stringifiedAddress = Inet6Address.numericToTextFormat(addr); 967 } 968 } 969 return stringifiedAddress; 970 } 971 972 /** 973 * Lookup the host name corresponding to the IP address provided. 974 * Search the configured host file a host name corresponding to 975 * the specified IP address. 976 * 977 * @param addr byte array representing an IP address 978 * @return {@code String} representing the host name mapping 979 * @throws UnknownHostException 980 * if no host found for the specified IP address 981 */ 982 @Override 983 public String getHostByAddr(byte[] addr) throws UnknownHostException { 984 String hostEntry; 985 String host = null; 986 987 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) { 988 while (hostsFileScanner.hasNextLine()) { 989 hostEntry = hostsFileScanner.nextLine(); 990 if (!hostEntry.startsWith("#")) { 991 hostEntry = removeComments(hostEntry); 992 String[] mapping = hostEntry.split("\\s+"); 993 if (mapping.length >= 2 && 994 Arrays.equals(addr, createAddressByteArray(mapping[0]))) { 995 host = mapping[1]; 996 break; 997 } 998 } 999 } 1000 } catch (FileNotFoundException e) { 1001 throw new UnknownHostException("Unable to resolve address " 1002 + Arrays.toString(addr) + " as hosts file " + hostsFile 1003 + " not found "); 1004 } 1005 1006 if ((host == null) || (host.isEmpty()) || (host.equals(" "))) { 1007 throw new UnknownHostException("Requested address " 1008 + Arrays.toString(addr) 1009 + " resolves to an invalid entry in hosts file " 1010 + hostsFile); 1011 } 1012 return host; 1013 } 1014 1015 /** 1016 * <p>Lookup a host mapping by name. Retrieve the IP addresses 1017 * associated with a host. 1018 * 1019 * <p>Search the configured hosts file for the addresses associated 1020 * with the specified host name. 1021 * 1022 * @param host the specified hostname 1023 * @return array of IP addresses for the requested host 1024 * @throws UnknownHostException 1025 * if no IP address for the {@code host} could be found 1026 */ 1027 public InetAddress[] lookupAllHostAddr(String host) 1028 throws UnknownHostException { 1029 String hostEntry; 1030 String addrStr = null; 1031 InetAddress[] res = null; 1032 byte addr[] = new byte[4]; 1033 ArrayList<InetAddress> inetAddresses = null; 1034 1035 // lookup the file and create a list InetAddress for the specified host 1036 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) { 1037 while (hostsFileScanner.hasNextLine()) { 1038 hostEntry = hostsFileScanner.nextLine(); 1039 if (!hostEntry.startsWith("#")) { 1040 hostEntry = removeComments(hostEntry); 1041 if (hostEntry.contains(host)) { 1042 addrStr = extractHostAddr(hostEntry, host); 1043 if ((addrStr != null) && (!addrStr.isEmpty())) { 1044 addr = createAddressByteArray(addrStr); 1045 if (inetAddresses == null) { 1046 inetAddresses = new ArrayList<>(1); 1047 } 1048 if (addr != null) { 1049 inetAddresses.add(InetAddress.getByAddress(host, addr)); 1050 } 1051 } 1052 } 1053 } 1054 } 1055 } catch (FileNotFoundException e) { 1056 throw new UnknownHostException("Unable to resolve host " + host 1057 + " as hosts file " + hostsFile + " not found "); 1058 } 1059 1060 if (inetAddresses != null) { 1061 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]); 1062 } else { 1063 throw new UnknownHostException("Unable to resolve host " + host 1064 + " in hosts file " + hostsFile); 1065 } 1066 return res; 1067 } 1068 1069 private String removeComments(String hostsEntry) { 1070 String filteredEntry = hostsEntry; 1071 int hashIndex; 1072 1073 if ((hashIndex = hostsEntry.indexOf("#")) != -1) { 1074 filteredEntry = hostsEntry.substring(0, hashIndex); 1075 } 1076 return filteredEntry; 1077 } 1078 1079 private byte [] createAddressByteArray(String addrStr) { 1080 byte[] addrArray; 1081 // check if IPV4 address - most likely 1082 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr); 1083 if (addrArray == null) { 1084 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr); 1085 } 1086 return addrArray; 1087 } 1088 1089 /** host to ip address mapping */ 1090 private String extractHostAddr(String hostEntry, String host) { 1091 String[] mapping = hostEntry.split("\\s+"); 1092 String hostAddr = null; 1093 1094 if (mapping.length >= 2) { 1095 // look at the host aliases 1096 for (int i = 1; i < mapping.length; i++) { 1097 if (mapping[i].equalsIgnoreCase(host)) { 1098 hostAddr = mapping[0]; 1099 } 1100 } 1101 } 1102 return hostAddr; 1103 } 1104 } 1105 1106 static final InetAddressImpl impl; 1107 1108 static { 1109 // create the impl 1110 impl = InetAddressImplFactory.create(); 1111 1112 // create name service 1113 nameService = createNameService(); 1114 } 1115 1116 /** 1117 * Create an instance of the NameService interface based on 1118 * the setting of the {@code jdk.net.hosts.file} system property. 1119 * 1120 * <p>The default NameService is the PlatformNameService, which typically 1121 * delegates name and address resolution calls to the underlying 1122 * OS network libraries. 1123 * 1124 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file} 1125 * system property is set. If the specified file doesn't exist, the name or 1126 * address lookup will result in an UnknownHostException. Thus, non existent 1127 * hosts file is handled as if the file is empty. 1128 * 1129 * @return a NameService 1130 */ 1131 private static NameService createNameService() { 1132 1133 String hostsFileName = 1134 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file"); 1135 NameService theNameService; 1136 if (hostsFileName != null) { 1137 theNameService = new HostsFileNameService(hostsFileName); 1138 } else { 1139 theNameService = new PlatformNameService(); 1140 } 1141 return theNameService; 1142 } 1143 1144 /** 1145 * Creates an InetAddress based on the provided host name and IP address. 1146 * No name service is checked for the validity of the address. 1147 * 1148 * <p> The host name can either be a machine name, such as 1149 * "{@code www.example.com}", or a textual representation of its IP 1150 * address. 1151 * <p> No validity checking is done on the host name either. 1152 * 1153 * <p> If addr specifies an IPv4 address an instance of Inet4Address 1154 * will be returned; otherwise, an instance of Inet6Address 1155 * will be returned. 1156 * 1157 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array 1158 * must be 16 bytes long 1159 * 1160 * @param host the specified host 1161 * @param addr the raw IP address in network byte order 1162 * @return an InetAddress object created from the raw IP address. 1163 * @exception UnknownHostException if IP address is of illegal length 1164 * @since 1.4 1165 */ 1166 public static InetAddress getByAddress(String host, byte[] addr) 1167 throws UnknownHostException { 1168 if (host != null && !host.isEmpty() && host.charAt(0) == '[') { 1169 if (host.charAt(host.length()-1) == ']') { 1170 host = host.substring(1, host.length() -1); 1171 } 1172 } 1173 if (addr != null) { 1174 if (addr.length == Inet4Address.INADDRSZ) { 1175 return new Inet4Address(host, addr); 1176 } else if (addr.length == Inet6Address.INADDRSZ) { 1177 byte[] newAddr 1178 = IPAddressUtil.convertFromIPv4MappedAddress(addr); 1179 if (newAddr != null) { 1180 return new Inet4Address(host, newAddr); 1181 } else { 1182 return new Inet6Address(host, addr); 1183 } 1184 } 1185 } 1186 throw new UnknownHostException("addr is of illegal length"); 1187 } 1188 1189 1190 /** 1191 * Determines the IP address of a host, given the host's name. 1192 * 1193 * <p> The host name can either be a machine name, such as 1194 * "{@code www.example.com}", or a textual representation of its 1195 * IP address. If a literal IP address is supplied, only the 1196 * validity of the address format is checked. 1197 * 1198 * <p> For {@code host} specified in literal IPv6 address, 1199 * either the form defined in RFC 2732 or the literal IPv6 address 1200 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also 1201 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6 1202 * scoped addresses. 1203 * 1204 * <p> If the host is {@code null} or {@code host.length()} is equal 1205 * to zero, then an {@code InetAddress} representing an address of the 1206 * loopback interface is returned. 1207 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1208 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1209 * section 2.5.3. 1210 * 1211 * <p> If there is a security manager, and {@code host} is not {@code null} 1212 * or {@code host.length() } is not equal to zero, the security manager's 1213 * {@code checkConnect} method is called with the hostname and {@code -1} 1214 * as its arguments to determine if the operation is allowed. 1215 * 1216 * @param host the specified host, or {@code null}. 1217 * @return an IP address for the given host name. 1218 * @exception UnknownHostException if no IP address for the 1219 * {@code host} could be found, or if a scope_id was specified 1220 * for a global IPv6 address. 1221 * @exception SecurityException if a security manager exists 1222 * and its checkConnect method doesn't allow the operation 1223 */ 1224 public static InetAddress getByName(String host) 1225 throws UnknownHostException { 1226 return InetAddress.getAllByName(host)[0]; 1227 } 1228 1229 // called from deployment cache manager 1230 private static InetAddress getByName(String host, InetAddress reqAddr) 1231 throws UnknownHostException { 1232 return InetAddress.getAllByName(host, reqAddr)[0]; 1233 } 1234 1235 /** 1236 * Given the name of a host, returns an array of its IP addresses, 1237 * based on the configured name service on the system. 1238 * 1239 * <p> The host name can either be a machine name, such as 1240 * "{@code www.example.com}", or a textual representation of its IP 1241 * address. If a literal IP address is supplied, only the 1242 * validity of the address format is checked. 1243 * 1244 * <p> For {@code host} specified in <i>literal IPv6 address</i>, 1245 * either the form defined in RFC 2732 or the literal IPv6 address 1246 * format defined in RFC 2373 is accepted. A literal IPv6 address may 1247 * also be qualified by appending a scoped zone identifier or scope_id. 1248 * The syntax and usage of scope_ids is described 1249 * <a href="Inet6Address.html#scoped">here</a>. 1250 * 1251 * <p> If the host is {@code null} or {@code host.length()} is equal 1252 * to zero, then an {@code InetAddress} representing an address of the 1253 * loopback interface is returned. 1254 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1255 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1256 * section 2.5.3. </p> 1257 * 1258 * <p> If there is a security manager, and {@code host} is not {@code null} 1259 * or {@code host.length() } is not equal to zero, the security manager's 1260 * {@code checkConnect} method is called with the hostname and {@code -1} 1261 * as its arguments to determine if the operation is allowed. 1262 * 1263 * @param host the name of the host, or {@code null}. 1264 * @return an array of all the IP addresses for a given host name. 1265 * 1266 * @exception UnknownHostException if no IP address for the 1267 * {@code host} could be found, or if a scope_id was specified 1268 * for a global IPv6 address. 1269 * @exception SecurityException if a security manager exists and its 1270 * {@code checkConnect} method doesn't allow the operation. 1271 * 1272 * @see SecurityManager#checkConnect 1273 */ 1274 public static InetAddress[] getAllByName(String host) 1275 throws UnknownHostException { 1276 return getAllByName(host, null); 1277 } 1278 1279 private static InetAddress[] getAllByName(String host, InetAddress reqAddr) 1280 throws UnknownHostException { 1281 1282 if (host == null || host.isEmpty()) { 1283 InetAddress[] ret = new InetAddress[1]; 1284 ret[0] = impl.loopbackAddress(); 1285 return ret; 1286 } 1287 1288 boolean ipv6Expected = false; 1289 if (host.charAt(0) == '[') { 1290 // This is supposed to be an IPv6 literal 1291 if (host.length() > 2 && host.charAt(host.length()-1) == ']') { 1292 host = host.substring(1, host.length() -1); 1293 ipv6Expected = true; 1294 } else { 1295 // This was supposed to be a IPv6 address, but it's not! 1296 throw new UnknownHostException(host + ": invalid IPv6 address"); 1297 } 1298 } 1299 1300 // if host is an IP address, we won't do further lookup 1301 if (Character.digit(host.charAt(0), 16) != -1 1302 || (host.charAt(0) == ':')) { 1303 byte[] addr = null; 1304 int numericZone = -1; 1305 String ifname = null; 1306 // see if it is IPv4 address 1307 addr = IPAddressUtil.textToNumericFormatV4(host); 1308 if (addr == null) { 1309 // This is supposed to be an IPv6 literal 1310 // Check if a numeric or string zone id is present 1311 int pos; 1312 if ((pos=host.indexOf ('%')) != -1) { 1313 numericZone = checkNumericZone (host); 1314 if (numericZone == -1) { /* remainder of string must be an ifname */ 1315 ifname = host.substring (pos+1); 1316 } 1317 } 1318 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) { 1319 throw new UnknownHostException(host + ": invalid IPv6 address"); 1320 } 1321 } else if (ipv6Expected) { 1322 // Means an IPv4 literal between brackets! 1323 throw new UnknownHostException("["+host+"]"); 1324 } 1325 InetAddress[] ret = new InetAddress[1]; 1326 if(addr != null) { 1327 if (addr.length == Inet4Address.INADDRSZ) { 1328 ret[0] = new Inet4Address(null, addr); 1329 } else { 1330 if (ifname != null) { 1331 ret[0] = new Inet6Address(null, addr, ifname); 1332 } else { 1333 ret[0] = new Inet6Address(null, addr, numericZone); 1334 } 1335 } 1336 return ret; 1337 } 1338 } else if (ipv6Expected) { 1339 // We were expecting an IPv6 Literal, but got something else 1340 throw new UnknownHostException("["+host+"]"); 1341 } 1342 return getAllByName0(host, reqAddr, true, true); 1343 } 1344 1345 /** 1346 * Returns the loopback address. 1347 * <p> 1348 * The InetAddress returned will represent the IPv4 1349 * loopback address, 127.0.0.1, or the IPv6 loopback 1350 * address, ::1. The IPv4 loopback address returned 1351 * is only one of many in the form 127.*.*.* 1352 * 1353 * @return the InetAddress loopback instance. 1354 * @since 1.7 1355 */ 1356 public static InetAddress getLoopbackAddress() { 1357 return impl.loopbackAddress(); 1358 } 1359 1360 1361 /** 1362 * check if the literal address string has %nn appended 1363 * returns -1 if not, or the numeric value otherwise. 1364 * 1365 * %nn may also be a string that represents the displayName of 1366 * a currently available NetworkInterface. 1367 */ 1368 private static int checkNumericZone (String s) throws UnknownHostException { 1369 int percent = s.indexOf ('%'); 1370 int slen = s.length(); 1371 int digit, zone=0; 1372 if (percent == -1) { 1373 return -1; 1374 } 1375 for (int i=percent+1; i<slen; i++) { 1376 char c = s.charAt(i); 1377 if (c == ']') { 1378 if (i == percent+1) { 1379 /* empty per-cent field */ 1380 return -1; 1381 } 1382 break; 1383 } 1384 if ((digit = Character.digit (c, 10)) < 0) { 1385 return -1; 1386 } 1387 zone = (zone * 10) + digit; 1388 } 1389 return zone; 1390 } 1391 1392 private static InetAddress[] getAllByName0 (String host) 1393 throws UnknownHostException 1394 { 1395 return getAllByName0(host, true); 1396 } 1397 1398 /** 1399 * package private so SocketPermission can call it 1400 */ 1401 static InetAddress[] getAllByName0 (String host, boolean check) 1402 throws UnknownHostException { 1403 return getAllByName0 (host, null, check, true); 1404 } 1405 1406 /** 1407 * Designated lookup method. 1408 * 1409 * @param host host name to look up 1410 * @param reqAddr requested address to be the 1st in returned array 1411 * @param check perform security check 1412 * @param useCache use cached value if not expired else always 1413 * perform name service lookup (and cache the result) 1414 * @return array of InetAddress(es) 1415 * @throws UnknownHostException if host name is not found 1416 */ 1417 private static InetAddress[] getAllByName0(String host, 1418 InetAddress reqAddr, 1419 boolean check, 1420 boolean useCache) 1421 throws UnknownHostException { 1422 1423 /* If it gets here it is presumed to be a hostname */ 1424 1425 /* make sure the connection to the host is allowed, before we 1426 * give out a hostname 1427 */ 1428 if (check) { 1429 SecurityManager security = System.getSecurityManager(); 1430 if (security != null) { 1431 security.checkConnect(host, -1); 1432 } 1433 } 1434 1435 // remove expired addresses from cache - expirySet keeps them ordered 1436 // by expiry time so we only need to iterate the prefix of the NavigableSet... 1437 long now = System.nanoTime(); 1438 for (CachedAddresses caddrs : expirySet) { 1439 // compare difference of time instants rather than 1440 // time instants directly, to avoid possible overflow. 1441 // (see System.nanoTime() recommendations...) 1442 if ((caddrs.expiryTime - now) < 0L) { 1443 // ConcurrentSkipListSet uses weakly consistent iterator, 1444 // so removing while iterating is OK... 1445 if (expirySet.remove(caddrs)) { 1446 // ... remove from cache 1447 cache.remove(caddrs.host, caddrs); 1448 } 1449 } else { 1450 // we encountered 1st element that expires in future 1451 break; 1452 } 1453 } 1454 1455 // look-up or remove from cache 1456 Addresses addrs; 1457 if (useCache) { 1458 addrs = cache.get(host); 1459 } else { 1460 addrs = cache.remove(host); 1461 if (addrs != null) { 1462 if (addrs instanceof CachedAddresses) { 1463 // try removing from expirySet too if CachedAddresses 1464 expirySet.remove(addrs); 1465 } 1466 addrs = null; 1467 } 1468 } 1469 1470 if (addrs == null) { 1471 // create a NameServiceAddresses instance which will look up 1472 // the name service and install it within cache... 1473 Addresses oldAddrs = cache.putIfAbsent( 1474 host, 1475 addrs = new NameServiceAddresses(host, reqAddr) 1476 ); 1477 if (oldAddrs != null) { // lost putIfAbsent race 1478 addrs = oldAddrs; 1479 } 1480 } 1481 1482 // ask Addresses to get an array of InetAddress(es) and clone it 1483 return addrs.get().clone(); 1484 } 1485 1486 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr) 1487 throws UnknownHostException 1488 { 1489 InetAddress[] addresses = null; 1490 UnknownHostException ex = null; 1491 1492 try { 1493 addresses = nameService.lookupAllHostAddr(host); 1494 } catch (UnknownHostException uhe) { 1495 if (host.equalsIgnoreCase("localhost")) { 1496 addresses = new InetAddress[] { impl.loopbackAddress() }; 1497 } 1498 else { 1499 ex = uhe; 1500 } 1501 } 1502 1503 if (addresses == null) { 1504 throw ex == null ? new UnknownHostException(host) : ex; 1505 } 1506 1507 // More to do? 1508 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) { 1509 // Find it? 1510 int i = 1; 1511 for (; i < addresses.length; i++) { 1512 if (addresses[i].equals(reqAddr)) { 1513 break; 1514 } 1515 } 1516 // Rotate 1517 if (i < addresses.length) { 1518 InetAddress tmp, tmp2 = reqAddr; 1519 for (int j = 0; j < i; j++) { 1520 tmp = addresses[j]; 1521 addresses[j] = tmp2; 1522 tmp2 = tmp; 1523 } 1524 addresses[i] = tmp2; 1525 } 1526 } 1527 1528 return addresses; 1529 } 1530 1531 /** 1532 * Returns an {@code InetAddress} object given the raw IP address . 1533 * The argument is in network byte order: the highest order 1534 * byte of the address is in {@code getAddress()[0]}. 1535 * 1536 * <p> This method doesn't block, i.e. no reverse name service lookup 1537 * is performed. 1538 * 1539 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array 1540 * must be 16 bytes long 1541 * 1542 * @param addr the raw IP address in network byte order 1543 * @return an InetAddress object created from the raw IP address. 1544 * @exception UnknownHostException if IP address is of illegal length 1545 * @since 1.4 1546 */ 1547 public static InetAddress getByAddress(byte[] addr) 1548 throws UnknownHostException { 1549 return getByAddress(null, addr); 1550 } 1551 1552 private static final class CachedLocalHost { 1553 final String host; 1554 final InetAddress addr; 1555 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s; 1556 1557 CachedLocalHost(String host, InetAddress addr) { 1558 this.host = host; 1559 this.addr = addr; 1560 } 1561 } 1562 1563 private static volatile CachedLocalHost cachedLocalHost; 1564 1565 /** 1566 * Returns the address of the local host. This is achieved by retrieving 1567 * the name of the host from the system, then resolving that name into 1568 * an {@code InetAddress}. 1569 * 1570 * <P>Note: The resolved address may be cached for a short period of time. 1571 * </P> 1572 * 1573 * <p>If there is a security manager, its 1574 * {@code checkConnect} method is called 1575 * with the local host name and {@code -1} 1576 * as its arguments to see if the operation is allowed. 1577 * If the operation is not allowed, an InetAddress representing 1578 * the loopback address is returned. 1579 * 1580 * @return the address of the local host. 1581 * 1582 * @exception UnknownHostException if the local host name could not 1583 * be resolved into an address. 1584 * 1585 * @see SecurityManager#checkConnect 1586 * @see java.net.InetAddress#getByName(java.lang.String) 1587 */ 1588 public static InetAddress getLocalHost() throws UnknownHostException { 1589 1590 SecurityManager security = System.getSecurityManager(); 1591 try { 1592 // is cached data still valid? 1593 CachedLocalHost clh = cachedLocalHost; 1594 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) { 1595 if (security != null) { 1596 security.checkConnect(clh.host, -1); 1597 } 1598 return clh.addr; 1599 } 1600 1601 String local = impl.getLocalHostName(); 1602 1603 if (security != null) { 1604 security.checkConnect(local, -1); 1605 } 1606 1607 InetAddress localAddr; 1608 if (local.equals("localhost")) { 1609 // shortcut for "localhost" host name 1610 localAddr = impl.loopbackAddress(); 1611 } else { 1612 // call getAllByName0 without security checks and 1613 // without using cached data 1614 try { 1615 localAddr = getAllByName0(local, null, false, false)[0]; 1616 } catch (UnknownHostException uhe) { 1617 // Rethrow with a more informative error message. 1618 UnknownHostException uhe2 = 1619 new UnknownHostException(local + ": " + 1620 uhe.getMessage()); 1621 uhe2.initCause(uhe); 1622 throw uhe2; 1623 } 1624 } 1625 cachedLocalHost = new CachedLocalHost(local, localAddr); 1626 return localAddr; 1627 } catch (java.lang.SecurityException e) { 1628 return impl.loopbackAddress(); 1629 } 1630 } 1631 1632 /** 1633 * Perform class load-time initializations. 1634 */ 1635 private static native void init(); 1636 1637 1638 /* 1639 * Returns the InetAddress representing anyLocalAddress 1640 * (typically 0.0.0.0 or ::0) 1641 */ 1642 static InetAddress anyLocalAddress() { 1643 return impl.anyLocalAddress(); 1644 } 1645 1646 /* 1647 * Load and instantiate an underlying impl class 1648 */ 1649 static InetAddressImpl loadImpl(String implName) { 1650 Object impl = null; 1651 1652 /* 1653 * Property "impl.prefix" will be prepended to the classname 1654 * of the implementation object we instantiate, to which we 1655 * delegate the real work (like native methods). This 1656 * property can vary across implementations of the java. 1657 * classes. The default is an empty String "". 1658 */ 1659 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", ""); 1660 try { 1661 @SuppressWarnings("deprecation") 1662 Object tmp = Class.forName("java.net." + prefix + implName).newInstance(); 1663 impl = tmp; 1664 } catch (ClassNotFoundException e) { 1665 System.err.println("Class not found: java.net." + prefix + 1666 implName + ":\ncheck impl.prefix property " + 1667 "in your properties file."); 1668 } catch (InstantiationException e) { 1669 System.err.println("Could not instantiate: java.net." + prefix + 1670 implName + ":\ncheck impl.prefix property " + 1671 "in your properties file."); 1672 } catch (IllegalAccessException e) { 1673 System.err.println("Cannot access class: java.net." + prefix + 1674 implName + ":\ncheck impl.prefix property " + 1675 "in your properties file."); 1676 } 1677 1678 if (impl == null) { 1679 try { 1680 @SuppressWarnings("deprecation") 1681 Object tmp = Class.forName(implName).newInstance(); 1682 impl = tmp; 1683 } catch (Exception e) { 1684 throw new Error("System property impl.prefix incorrect"); 1685 } 1686 } 1687 1688 return (InetAddressImpl) impl; 1689 } 1690 1691 private void readObjectNoData () { 1692 if (getClass().getClassLoader() != null) { 1693 throw new SecurityException ("invalid address type"); 1694 } 1695 } 1696 1697 private static final jdk.internal.misc.Unsafe UNSAFE 1698 = jdk.internal.misc.Unsafe.getUnsafe(); 1699 private static final long FIELDS_OFFSET 1700 = UNSAFE.objectFieldOffset(InetAddress.class, "holder"); 1701 1702 private void readObject (ObjectInputStream s) throws 1703 IOException, ClassNotFoundException { 1704 if (getClass().getClassLoader() != null) { 1705 throw new SecurityException ("invalid address type"); 1706 } 1707 GetField gf = s.readFields(); 1708 String host = (String)gf.get("hostName", null); 1709 int address = gf.get("address", 0); 1710 int family = gf.get("family", 0); 1711 if (family != IPv4 && family != IPv6) { 1712 throw new InvalidObjectException("invalid address family type: " + family); 1713 } 1714 InetAddressHolder h = new InetAddressHolder(host, address, family); 1715 UNSAFE.putReference(this, FIELDS_OFFSET, h); 1716 } 1717 1718 /* needed because the serializable fields no longer exist */ 1719 1720 /** 1721 * @serialField hostName String 1722 * @serialField address int 1723 * @serialField family int 1724 */ 1725 private static final ObjectStreamField[] serialPersistentFields = { 1726 new ObjectStreamField("hostName", String.class), 1727 new ObjectStreamField("address", int.class), 1728 new ObjectStreamField("family", int.class), 1729 }; 1730 1731 private void writeObject (ObjectOutputStream s) throws 1732 IOException { 1733 if (getClass().getClassLoader() != null) { 1734 throw new SecurityException ("invalid address type"); 1735 } 1736 PutField pf = s.putFields(); 1737 pf.put("hostName", holder().getHostName()); 1738 pf.put("address", holder().getAddress()); 1739 pf.put("family", holder().getFamily()); 1740 s.writeFields(); 1741 } 1742 } 1743 1744 /* 1745 * Simple factory to create the impl 1746 */ 1747 class InetAddressImplFactory { 1748 1749 static InetAddressImpl create() { 1750 return InetAddress.loadImpl(isIPv6Supported() ? 1751 "Inet6AddressImpl" : "Inet4AddressImpl"); 1752 } 1753 1754 static native boolean isIPv6Supported(); 1755 }