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 @java.io.Serial 303 private static final long serialVersionUID = 3286316764910316507L; 304 305 /* 306 * Load net library into runtime, and perform initializations. 307 */ 308 static { 309 String str = GetPropertyAction.privilegedGetProperty("java.net.preferIPv6Addresses"); 310 if (str == null) { 311 preferIPv6Address = PREFER_IPV4_VALUE; 312 } else if (str.equalsIgnoreCase("true")) { 313 preferIPv6Address = PREFER_IPV6_VALUE; 314 } else if (str.equalsIgnoreCase("false")) { 315 preferIPv6Address = PREFER_IPV4_VALUE; 316 } else if (str.equalsIgnoreCase("system")) { 317 preferIPv6Address = PREFER_SYSTEM_VALUE; 318 } else { 319 preferIPv6Address = PREFER_IPV4_VALUE; 320 } 321 jdk.internal.loader.BootLoader.loadLibrary("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 @java.io.Serial 358 private Object readResolve() throws ObjectStreamException { 359 // will replace the deserialized 'this' object 360 return new Inet4Address(holder().getHostName(), holder().getAddress()); 361 } 362 363 /** 364 * Utility routine to check if the InetAddress is an 365 * IP multicast address. 366 * @return a {@code boolean} indicating if the InetAddress is 367 * an IP multicast address 368 * @since 1.1 369 */ 370 public boolean isMulticastAddress() { 371 return false; 372 } 373 374 /** 375 * Utility routine to check if the InetAddress is a wildcard address. 376 * @return a {@code boolean} indicating if the InetAddress is 377 * a wildcard address. 378 * @since 1.4 379 */ 380 public boolean isAnyLocalAddress() { 381 return false; 382 } 383 384 /** 385 * Utility routine to check if the InetAddress is a loopback address. 386 * 387 * @return a {@code boolean} indicating if the InetAddress is 388 * a loopback address; or false otherwise. 389 * @since 1.4 390 */ 391 public boolean isLoopbackAddress() { 392 return false; 393 } 394 395 /** 396 * Utility routine to check if the InetAddress is an link local address. 397 * 398 * @return a {@code boolean} indicating if the InetAddress is 399 * a link local address; or false if address is not a link local unicast address. 400 * @since 1.4 401 */ 402 public boolean isLinkLocalAddress() { 403 return false; 404 } 405 406 /** 407 * Utility routine to check if the InetAddress is a site local address. 408 * 409 * @return a {@code boolean} indicating if the InetAddress is 410 * a site local address; or false if address is not a site local unicast address. 411 * @since 1.4 412 */ 413 public boolean isSiteLocalAddress() { 414 return false; 415 } 416 417 /** 418 * Utility routine to check if the multicast address has global scope. 419 * 420 * @return a {@code boolean} indicating if the address has 421 * is a multicast address of global scope, false if it is not 422 * of global scope or it is not a multicast address 423 * @since 1.4 424 */ 425 public boolean isMCGlobal() { 426 return false; 427 } 428 429 /** 430 * Utility routine to check if the multicast address has node scope. 431 * 432 * @return a {@code boolean} indicating if the address has 433 * is a multicast address of node-local scope, false if it is not 434 * of node-local scope or it is not a multicast address 435 * @since 1.4 436 */ 437 public boolean isMCNodeLocal() { 438 return false; 439 } 440 441 /** 442 * Utility routine to check if the multicast address has link scope. 443 * 444 * @return a {@code boolean} indicating if the address has 445 * is a multicast address of link-local scope, false if it is not 446 * of link-local scope or it is not a multicast address 447 * @since 1.4 448 */ 449 public boolean isMCLinkLocal() { 450 return false; 451 } 452 453 /** 454 * Utility routine to check if the multicast address has site scope. 455 * 456 * @return a {@code boolean} indicating if the address has 457 * is a multicast address of site-local scope, false if it is not 458 * of site-local scope or it is not a multicast address 459 * @since 1.4 460 */ 461 public boolean isMCSiteLocal() { 462 return false; 463 } 464 465 /** 466 * Utility routine to check if the multicast address has organization scope. 467 * 468 * @return a {@code boolean} indicating if the address has 469 * is a multicast address of organization-local scope, 470 * false if it is not of organization-local scope 471 * or it is not a multicast address 472 * @since 1.4 473 */ 474 public boolean isMCOrgLocal() { 475 return false; 476 } 477 478 479 /** 480 * Test whether that address is reachable. Best effort is made by the 481 * implementation to try to reach the host, but firewalls and server 482 * configuration may block requests resulting in a unreachable status 483 * while some specific ports may be accessible. 484 * A typical implementation will use ICMP ECHO REQUESTs if the 485 * privilege can be obtained, otherwise it will try to establish 486 * a TCP connection on port 7 (Echo) of the destination host. 487 * <p> 488 * The timeout value, in milliseconds, indicates the maximum amount of time 489 * the try should take. If the operation times out before getting an 490 * answer, the host is deemed unreachable. A negative value will result 491 * in an IllegalArgumentException being thrown. 492 * 493 * @param timeout the time, in milliseconds, before the call aborts 494 * @return a {@code boolean} indicating if the address is reachable. 495 * @throws IOException if a network error occurs 496 * @throws IllegalArgumentException if {@code timeout} is negative. 497 * @since 1.5 498 */ 499 public boolean isReachable(int timeout) throws IOException { 500 return isReachable(null, 0 , timeout); 501 } 502 503 /** 504 * Test whether that address is reachable. Best effort is made by the 505 * implementation to try to reach the host, but firewalls and server 506 * configuration may block requests resulting in a unreachable status 507 * while some specific ports may be accessible. 508 * A typical implementation will use ICMP ECHO REQUESTs if the 509 * privilege can be obtained, otherwise it will try to establish 510 * a TCP connection on port 7 (Echo) of the destination host. 511 * <p> 512 * The {@code network interface} and {@code ttl} parameters 513 * let the caller specify which network interface the test will go through 514 * and the maximum number of hops the packets should go through. 515 * A negative value for the {@code ttl} will result in an 516 * IllegalArgumentException being thrown. 517 * <p> 518 * The timeout value, in milliseconds, indicates the maximum amount of time 519 * the try should take. If the operation times out before getting an 520 * answer, the host is deemed unreachable. A negative value will result 521 * in an IllegalArgumentException being thrown. 522 * 523 * @param netif the NetworkInterface through which the 524 * test will be done, or null for any interface 525 * @param ttl the maximum numbers of hops to try or 0 for the 526 * default 527 * @param timeout the time, in milliseconds, before the call aborts 528 * @throws IllegalArgumentException if either {@code timeout} 529 * or {@code ttl} are negative. 530 * @return a {@code boolean} indicating if the address is reachable. 531 * @throws IOException if a network error occurs 532 * @since 1.5 533 */ 534 public boolean isReachable(NetworkInterface netif, int ttl, 535 int timeout) throws IOException { 536 if (ttl < 0) 537 throw new IllegalArgumentException("ttl can't be negative"); 538 if (timeout < 0) 539 throw new IllegalArgumentException("timeout can't be negative"); 540 541 return impl.isReachable(this, timeout, netif, ttl); 542 } 543 544 /** 545 * Gets the host name for this IP address. 546 * 547 * <p>If this InetAddress was created with a host name, 548 * this host name will be remembered and returned; 549 * otherwise, a reverse name lookup will be performed 550 * and the result will be returned based on the system 551 * configured name lookup service. If a lookup of the name service 552 * is required, call 553 * {@link #getCanonicalHostName() getCanonicalHostName}. 554 * 555 * <p>If there is a security manager, its 556 * {@code checkConnect} method is first called 557 * with the hostname and {@code -1} 558 * as its arguments to see if the operation is allowed. 559 * If the operation is not allowed, it will return 560 * the textual representation of the IP address. 561 * 562 * @return the host name for this IP address, or if the operation 563 * is not allowed by the security check, the textual 564 * representation of the IP address. 565 * 566 * @see InetAddress#getCanonicalHostName 567 * @see SecurityManager#checkConnect 568 */ 569 public String getHostName() { 570 return getHostName(true); 571 } 572 573 /** 574 * Returns the hostname for this address. 575 * If the host is equal to null, then this address refers to any 576 * of the local machine's available network addresses. 577 * this is package private so SocketPermission can make calls into 578 * here without a security check. 579 * 580 * <p>If there is a security manager, this method first 581 * calls its {@code checkConnect} method 582 * with the hostname and {@code -1} 583 * as its arguments to see if the calling code is allowed to know 584 * the hostname for this IP address, i.e., to connect to the host. 585 * If the operation is not allowed, it will return 586 * the textual representation of the IP address. 587 * 588 * @return the host name for this IP address, or if the operation 589 * is not allowed by the security check, the textual 590 * representation of the IP address. 591 * 592 * @param check make security check if true 593 * 594 * @see SecurityManager#checkConnect 595 */ 596 String getHostName(boolean check) { 597 if (holder().getHostName() == null) { 598 holder().hostName = InetAddress.getHostFromNameService(this, check); 599 } 600 return holder().getHostName(); 601 } 602 603 /** 604 * Gets the fully qualified domain name for this IP address. 605 * Best effort method, meaning we may not be able to return 606 * the FQDN depending on the underlying system configuration. 607 * 608 * <p>If there is a security manager, this method first 609 * calls its {@code checkConnect} method 610 * with the hostname and {@code -1} 611 * as its arguments to see if the calling code is allowed to know 612 * the hostname for this IP address, i.e., to connect to the host. 613 * If the operation is not allowed, it will return 614 * the textual representation of the IP address. 615 * 616 * @return the fully qualified domain name for this IP address, 617 * or if the operation is not allowed by the security check, 618 * the textual representation of the IP address. 619 * 620 * @see SecurityManager#checkConnect 621 * 622 * @since 1.4 623 */ 624 public String getCanonicalHostName() { 625 String value = canonicalHostName; 626 if (value == null) 627 canonicalHostName = value = 628 InetAddress.getHostFromNameService(this, true); 629 return value; 630 } 631 632 /** 633 * Returns the hostname for this address. 634 * 635 * <p>If there is a security manager, this method first 636 * calls its {@code checkConnect} method 637 * with the hostname and {@code -1} 638 * as its arguments to see if the calling code is allowed to know 639 * the hostname for this IP address, i.e., to connect to the host. 640 * If the operation is not allowed, it will return 641 * the textual representation of the IP address. 642 * 643 * @return the host name for this IP address, or if the operation 644 * is not allowed by the security check, the textual 645 * representation of the IP address. 646 * 647 * @param check make security check if true 648 * 649 * @see SecurityManager#checkConnect 650 */ 651 private static String getHostFromNameService(InetAddress addr, boolean check) { 652 String host = null; 653 try { 654 // first lookup the hostname 655 host = nameService.getHostByAddr(addr.getAddress()); 656 657 /* check to see if calling code is allowed to know 658 * the hostname for this IP address, ie, connect to the host 659 */ 660 if (check) { 661 SecurityManager sec = System.getSecurityManager(); 662 if (sec != null) { 663 sec.checkConnect(host, -1); 664 } 665 } 666 667 /* now get all the IP addresses for this hostname, 668 * and make sure one of them matches the original IP 669 * address. We do this to try and prevent spoofing. 670 */ 671 672 InetAddress[] arr = InetAddress.getAllByName0(host, check); 673 boolean ok = false; 674 675 if(arr != null) { 676 for(int i = 0; !ok && i < arr.length; i++) { 677 ok = addr.equals(arr[i]); 678 } 679 } 680 681 //XXX: if it looks a spoof just return the address? 682 if (!ok) { 683 host = addr.getHostAddress(); 684 return host; 685 } 686 } catch (SecurityException e) { 687 host = addr.getHostAddress(); 688 } catch (UnknownHostException e) { 689 host = addr.getHostAddress(); 690 // let next provider resolve the hostname 691 } 692 return host; 693 } 694 695 /** 696 * Returns the raw IP address of this {@code InetAddress} 697 * object. The result is in network byte order: the highest order 698 * byte of the address is in {@code getAddress()[0]}. 699 * 700 * @return the raw IP address of this object. 701 */ 702 public byte[] getAddress() { 703 return null; 704 } 705 706 /** 707 * Returns the IP address string in textual presentation. 708 * 709 * @return the raw IP address in a string format. 710 * @since 1.0.2 711 */ 712 public String getHostAddress() { 713 return null; 714 } 715 716 /** 717 * Returns a hashcode for this IP address. 718 * 719 * @return a hash code value for this IP address. 720 */ 721 public int hashCode() { 722 return -1; 723 } 724 725 /** 726 * Compares this object against the specified object. 727 * The result is {@code true} if and only if the argument is 728 * not {@code null} and it represents the same IP address as 729 * this object. 730 * <p> 731 * Two instances of {@code InetAddress} represent the same IP 732 * address if the length of the byte arrays returned by 733 * {@code getAddress} is the same for both, and each of the 734 * array components is the same for the byte arrays. 735 * 736 * @param obj the object to compare against. 737 * @return {@code true} if the objects are the same; 738 * {@code false} otherwise. 739 * @see java.net.InetAddress#getAddress() 740 */ 741 public boolean equals(Object obj) { 742 return false; 743 } 744 745 /** 746 * Converts this IP address to a {@code String}. The 747 * string returned is of the form: hostname / literal IP 748 * address. 749 * 750 * If the host name is unresolved, no reverse name service lookup 751 * is performed. The hostname part will be represented by an empty string. 752 * 753 * @return a string representation of this IP address. 754 */ 755 public String toString() { 756 String hostName = holder().getHostName(); 757 return Objects.toString(hostName, "") 758 + "/" + getHostAddress(); 759 } 760 761 // mapping from host name to Addresses - either NameServiceAddresses (while 762 // still being looked-up by NameService(s)) or CachedAddresses when cached 763 private static final ConcurrentMap<String, Addresses> cache = 764 new ConcurrentHashMap<>(); 765 766 // CachedAddresses that have to expire are kept ordered in this NavigableSet 767 // which is scanned on each access 768 private static final NavigableSet<CachedAddresses> expirySet = 769 new ConcurrentSkipListSet<>(); 770 771 // common interface 772 private interface Addresses { 773 InetAddress[] get() throws UnknownHostException; 774 } 775 776 // a holder for cached addresses with required metadata 777 private static final class CachedAddresses implements Addresses, Comparable<CachedAddresses> { 778 private static final AtomicLong seq = new AtomicLong(); 779 final String host; 780 final InetAddress[] inetAddresses; 781 final long expiryTime; // time of expiry (in terms of System.nanoTime()) 782 final long id = seq.incrementAndGet(); // each instance is unique 783 784 CachedAddresses(String host, InetAddress[] inetAddresses, long expiryTime) { 785 this.host = host; 786 this.inetAddresses = inetAddresses; 787 this.expiryTime = expiryTime; 788 } 789 790 @Override 791 public InetAddress[] get() throws UnknownHostException { 792 if (inetAddresses == null) { 793 throw new UnknownHostException(host); 794 } 795 return inetAddresses; 796 } 797 798 @Override 799 public int compareTo(CachedAddresses other) { 800 // natural order is expiry time - 801 // compare difference of expiry times rather than 802 // expiry times directly, to avoid possible overflow. 803 // (see System.nanoTime() recommendations...) 804 long diff = this.expiryTime - other.expiryTime; 805 if (diff < 0L) return -1; 806 if (diff > 0L) return 1; 807 // ties are broken using unique id 808 return Long.compare(this.id, other.id); 809 } 810 } 811 812 // a name service lookup based Addresses implementation which replaces itself 813 // in cache when the result is obtained 814 private static final class NameServiceAddresses implements Addresses { 815 private final String host; 816 private final InetAddress reqAddr; 817 818 NameServiceAddresses(String host, InetAddress reqAddr) { 819 this.host = host; 820 this.reqAddr = reqAddr; 821 } 822 823 @Override 824 public InetAddress[] get() throws UnknownHostException { 825 Addresses addresses; 826 // only one thread is doing lookup to name service 827 // for particular host at any time. 828 synchronized (this) { 829 // re-check that we are still us + re-install us if slot empty 830 addresses = cache.putIfAbsent(host, this); 831 if (addresses == null) { 832 // this can happen when we were replaced by CachedAddresses in 833 // some other thread, then CachedAddresses expired and were 834 // removed from cache while we were waiting for lock... 835 addresses = this; 836 } 837 // still us ? 838 if (addresses == this) { 839 // lookup name services 840 InetAddress[] inetAddresses; 841 UnknownHostException ex; 842 int cachePolicy; 843 try { 844 inetAddresses = getAddressesFromNameService(host, reqAddr); 845 ex = null; 846 cachePolicy = InetAddressCachePolicy.get(); 847 } catch (UnknownHostException uhe) { 848 inetAddresses = null; 849 ex = uhe; 850 cachePolicy = InetAddressCachePolicy.getNegative(); 851 } 852 // remove or replace us with cached addresses according to cachePolicy 853 if (cachePolicy == InetAddressCachePolicy.NEVER) { 854 cache.remove(host, this); 855 } else { 856 CachedAddresses cachedAddresses = new CachedAddresses( 857 host, 858 inetAddresses, 859 cachePolicy == InetAddressCachePolicy.FOREVER 860 ? 0L 861 // cachePolicy is in [s] - we need [ns] 862 : System.nanoTime() + 1000_000_000L * cachePolicy 863 ); 864 if (cache.replace(host, this, cachedAddresses) && 865 cachePolicy != InetAddressCachePolicy.FOREVER) { 866 // schedule expiry 867 expirySet.add(cachedAddresses); 868 } 869 } 870 if (inetAddresses == null) { 871 throw ex == null ? new UnknownHostException(host) : ex; 872 } 873 return inetAddresses; 874 } 875 // else addresses != this 876 } 877 // delegate to different addresses when we are already replaced 878 // but outside of synchronized block to avoid any chance of dead-locking 879 return addresses.get(); 880 } 881 } 882 883 /** 884 * NameService provides host and address lookup service 885 * 886 * @since 9 887 */ 888 private interface NameService { 889 890 /** 891 * Lookup a host mapping by name. Retrieve the IP addresses 892 * associated with a host 893 * 894 * @param host the specified hostname 895 * @return array of IP addresses for the requested host 896 * @throws UnknownHostException 897 * if no IP address for the {@code host} could be found 898 */ 899 InetAddress[] lookupAllHostAddr(String host) 900 throws UnknownHostException; 901 902 /** 903 * Lookup the host corresponding to the IP address provided 904 * 905 * @param addr byte array representing an IP address 906 * @return {@code String} representing the host name mapping 907 * @throws UnknownHostException 908 * if no host found for the specified IP address 909 */ 910 String getHostByAddr(byte[] addr) throws UnknownHostException; 911 912 } 913 914 /** 915 * The default NameService implementation, which delegates to the underlying 916 * OS network libraries to resolve host address mappings. 917 * 918 * @since 9 919 */ 920 private static final class PlatformNameService implements NameService { 921 922 public InetAddress[] lookupAllHostAddr(String host) 923 throws UnknownHostException 924 { 925 return impl.lookupAllHostAddr(host); 926 } 927 928 public String getHostByAddr(byte[] addr) 929 throws UnknownHostException 930 { 931 return impl.getHostByAddr(addr); 932 } 933 } 934 935 /** 936 * The HostsFileNameService provides host address mapping 937 * by reading the entries in a hosts file, which is specified by 938 * {@code jdk.net.hosts.file} system property 939 * 940 * <p>The file format is that which corresponds with the /etc/hosts file 941 * IP Address host alias list. 942 * 943 * <p>When the file lookup is enabled it replaces the default NameService 944 * implementation 945 * 946 * @since 9 947 */ 948 private static final class HostsFileNameService implements NameService { 949 950 private final String hostsFile; 951 952 public HostsFileNameService (String hostsFileName) { 953 this.hostsFile = hostsFileName; 954 } 955 956 private String addrToString(byte addr[]) { 957 String stringifiedAddress = null; 958 959 if (addr.length == Inet4Address.INADDRSZ) { 960 stringifiedAddress = Inet4Address.numericToTextFormat(addr); 961 } else { // treat as an IPV6 jobby 962 byte[] newAddr 963 = IPAddressUtil.convertFromIPv4MappedAddress(addr); 964 if (newAddr != null) { 965 stringifiedAddress = Inet4Address.numericToTextFormat(addr); 966 } else { 967 stringifiedAddress = Inet6Address.numericToTextFormat(addr); 968 } 969 } 970 return stringifiedAddress; 971 } 972 973 /** 974 * Lookup the host name corresponding to the IP address provided. 975 * Search the configured host file a host name corresponding to 976 * the specified IP address. 977 * 978 * @param addr byte array representing an IP address 979 * @return {@code String} representing the host name mapping 980 * @throws UnknownHostException 981 * if no host found for the specified IP address 982 */ 983 @Override 984 public String getHostByAddr(byte[] addr) throws UnknownHostException { 985 String hostEntry; 986 String host = null; 987 988 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) { 989 while (hostsFileScanner.hasNextLine()) { 990 hostEntry = hostsFileScanner.nextLine(); 991 if (!hostEntry.startsWith("#")) { 992 hostEntry = removeComments(hostEntry); 993 String[] mapping = hostEntry.split("\\s+"); 994 if (mapping.length >= 2 && 995 Arrays.equals(addr, createAddressByteArray(mapping[0]))) { 996 host = mapping[1]; 997 break; 998 } 999 } 1000 } 1001 } catch (FileNotFoundException e) { 1002 throw new UnknownHostException("Unable to resolve address " 1003 + Arrays.toString(addr) + " as hosts file " + hostsFile 1004 + " not found "); 1005 } 1006 1007 if ((host == null) || (host.isEmpty()) || (host.equals(" "))) { 1008 throw new UnknownHostException("Requested address " 1009 + Arrays.toString(addr) 1010 + " resolves to an invalid entry in hosts file " 1011 + hostsFile); 1012 } 1013 return host; 1014 } 1015 1016 /** 1017 * <p>Lookup a host mapping by name. Retrieve the IP addresses 1018 * associated with a host. 1019 * 1020 * <p>Search the configured hosts file for the addresses associated 1021 * with the specified host name. 1022 * 1023 * @param host the specified hostname 1024 * @return array of IP addresses for the requested host 1025 * @throws UnknownHostException 1026 * if no IP address for the {@code host} could be found 1027 */ 1028 public InetAddress[] lookupAllHostAddr(String host) 1029 throws UnknownHostException { 1030 String hostEntry; 1031 String addrStr = null; 1032 InetAddress[] res = null; 1033 byte addr[] = new byte[4]; 1034 ArrayList<InetAddress> inetAddresses = null; 1035 1036 // lookup the file and create a list InetAddress for the specified host 1037 try (Scanner hostsFileScanner = new Scanner(new File(hostsFile), "UTF-8")) { 1038 while (hostsFileScanner.hasNextLine()) { 1039 hostEntry = hostsFileScanner.nextLine(); 1040 if (!hostEntry.startsWith("#")) { 1041 hostEntry = removeComments(hostEntry); 1042 if (hostEntry.contains(host)) { 1043 addrStr = extractHostAddr(hostEntry, host); 1044 if ((addrStr != null) && (!addrStr.isEmpty())) { 1045 addr = createAddressByteArray(addrStr); 1046 if (inetAddresses == null) { 1047 inetAddresses = new ArrayList<>(1); 1048 } 1049 if (addr != null) { 1050 inetAddresses.add(InetAddress.getByAddress(host, addr)); 1051 } 1052 } 1053 } 1054 } 1055 } 1056 } catch (FileNotFoundException e) { 1057 throw new UnknownHostException("Unable to resolve host " + host 1058 + " as hosts file " + hostsFile + " not found "); 1059 } 1060 1061 if (inetAddresses != null) { 1062 res = inetAddresses.toArray(new InetAddress[inetAddresses.size()]); 1063 } else { 1064 throw new UnknownHostException("Unable to resolve host " + host 1065 + " in hosts file " + hostsFile); 1066 } 1067 return res; 1068 } 1069 1070 private String removeComments(String hostsEntry) { 1071 String filteredEntry = hostsEntry; 1072 int hashIndex; 1073 1074 if ((hashIndex = hostsEntry.indexOf("#")) != -1) { 1075 filteredEntry = hostsEntry.substring(0, hashIndex); 1076 } 1077 return filteredEntry; 1078 } 1079 1080 private byte [] createAddressByteArray(String addrStr) { 1081 byte[] addrArray; 1082 // check if IPV4 address - most likely 1083 addrArray = IPAddressUtil.textToNumericFormatV4(addrStr); 1084 if (addrArray == null) { 1085 addrArray = IPAddressUtil.textToNumericFormatV6(addrStr); 1086 } 1087 return addrArray; 1088 } 1089 1090 /** host to ip address mapping */ 1091 private String extractHostAddr(String hostEntry, String host) { 1092 String[] mapping = hostEntry.split("\\s+"); 1093 String hostAddr = null; 1094 1095 if (mapping.length >= 2) { 1096 // look at the host aliases 1097 for (int i = 1; i < mapping.length; i++) { 1098 if (mapping[i].equalsIgnoreCase(host)) { 1099 hostAddr = mapping[0]; 1100 } 1101 } 1102 } 1103 return hostAddr; 1104 } 1105 } 1106 1107 static final InetAddressImpl impl; 1108 1109 static { 1110 // create the impl 1111 impl = InetAddressImplFactory.create(); 1112 1113 // create name service 1114 nameService = createNameService(); 1115 } 1116 1117 /** 1118 * Create an instance of the NameService interface based on 1119 * the setting of the {@code jdk.net.hosts.file} system property. 1120 * 1121 * <p>The default NameService is the PlatformNameService, which typically 1122 * delegates name and address resolution calls to the underlying 1123 * OS network libraries. 1124 * 1125 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file} 1126 * system property is set. If the specified file doesn't exist, the name or 1127 * address lookup will result in an UnknownHostException. Thus, non existent 1128 * hosts file is handled as if the file is empty. 1129 * 1130 * @return a NameService 1131 */ 1132 private static NameService createNameService() { 1133 1134 String hostsFileName = 1135 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file"); 1136 NameService theNameService; 1137 if (hostsFileName != null) { 1138 theNameService = new HostsFileNameService(hostsFileName); 1139 } else { 1140 theNameService = new PlatformNameService(); 1141 } 1142 return theNameService; 1143 } 1144 1145 /** 1146 * Creates an InetAddress based on the provided host name and IP address. 1147 * No name service is checked for the validity of the address. 1148 * 1149 * <p> The host name can either be a machine name, such as 1150 * "{@code www.example.com}", or a textual representation of its IP 1151 * address. 1152 * <p> No validity checking is done on the host name either. 1153 * 1154 * <p> If addr specifies an IPv4 address an instance of Inet4Address 1155 * will be returned; otherwise, an instance of Inet6Address 1156 * will be returned. 1157 * 1158 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array 1159 * must be 16 bytes long 1160 * 1161 * @param host the specified host 1162 * @param addr the raw IP address in network byte order 1163 * @return an InetAddress object created from the raw IP address. 1164 * @exception UnknownHostException if IP address is of illegal length 1165 * @since 1.4 1166 */ 1167 public static InetAddress getByAddress(String host, byte[] addr) 1168 throws UnknownHostException { 1169 if (host != null && !host.isEmpty() && host.charAt(0) == '[') { 1170 if (host.charAt(host.length()-1) == ']') { 1171 host = host.substring(1, host.length() -1); 1172 } 1173 } 1174 if (addr != null) { 1175 if (addr.length == Inet4Address.INADDRSZ) { 1176 return new Inet4Address(host, addr); 1177 } else if (addr.length == Inet6Address.INADDRSZ) { 1178 byte[] newAddr 1179 = IPAddressUtil.convertFromIPv4MappedAddress(addr); 1180 if (newAddr != null) { 1181 return new Inet4Address(host, newAddr); 1182 } else { 1183 return new Inet6Address(host, addr); 1184 } 1185 } 1186 } 1187 throw new UnknownHostException("addr is of illegal length"); 1188 } 1189 1190 1191 /** 1192 * Determines the IP address of a host, given the host's name. 1193 * 1194 * <p> The host name can either be a machine name, such as 1195 * "{@code www.example.com}", or a textual representation of its 1196 * IP address. If a literal IP address is supplied, only the 1197 * validity of the address format is checked. 1198 * 1199 * <p> For {@code host} specified in literal IPv6 address, 1200 * either the form defined in RFC 2732 or the literal IPv6 address 1201 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also 1202 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6 1203 * scoped addresses. 1204 * 1205 * <p> If the host is {@code null} or {@code host.length()} is equal 1206 * to zero, then an {@code InetAddress} representing an address of the 1207 * loopback interface is returned. 1208 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1209 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1210 * section 2.5.3. 1211 * 1212 * <p> If there is a security manager, and {@code host} is not {@code null} 1213 * or {@code host.length() } is not equal to zero, the security manager's 1214 * {@code checkConnect} method is called with the hostname and {@code -1} 1215 * as its arguments to determine if the operation is allowed. 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 www.example.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 * 1252 * <p> If the host is {@code null} or {@code host.length()} is equal 1253 * to zero, then an {@code InetAddress} representing an address of the 1254 * loopback interface is returned. 1255 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1256 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1257 * section 2.5.3. </p> 1258 * 1259 * <p> If there is a security manager, and {@code host} is not {@code null} 1260 * or {@code host.length() } is not equal to zero, the security manager's 1261 * {@code checkConnect} method is called with the hostname and {@code -1} 1262 * as its arguments to determine 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.isEmpty()) { 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 literal 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 Literal, 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 @java.io.Serial 1693 private void readObjectNoData () { 1694 if (getClass().getClassLoader() != null) { 1695 throw new SecurityException ("invalid address type"); 1696 } 1697 } 1698 1699 private static final jdk.internal.misc.Unsafe UNSAFE 1700 = jdk.internal.misc.Unsafe.getUnsafe(); 1701 private static final long FIELDS_OFFSET 1702 = UNSAFE.objectFieldOffset(InetAddress.class, "holder"); 1703 1704 @java.io.Serial 1705 private void readObject (ObjectInputStream s) throws 1706 IOException, ClassNotFoundException { 1707 if (getClass().getClassLoader() != null) { 1708 throw new SecurityException ("invalid address type"); 1709 } 1710 GetField gf = s.readFields(); 1711 String host = (String)gf.get("hostName", null); 1712 int address = gf.get("address", 0); 1713 int family = gf.get("family", 0); 1714 if (family != IPv4 && family != IPv6) { 1715 throw new InvalidObjectException("invalid address family type: " + family); 1716 } 1717 InetAddressHolder h = new InetAddressHolder(host, address, family); 1718 UNSAFE.putReference(this, FIELDS_OFFSET, h); 1719 } 1720 1721 /* needed because the serializable fields no longer exist */ 1722 1723 /** 1724 * @serialField hostName String 1725 * @serialField address int 1726 * @serialField family int 1727 */ 1728 @java.io.Serial 1729 private static final ObjectStreamField[] serialPersistentFields = { 1730 new ObjectStreamField("hostName", String.class), 1731 new ObjectStreamField("address", int.class), 1732 new ObjectStreamField("family", int.class), 1733 }; 1734 1735 @java.io.Serial 1736 private void writeObject (ObjectOutputStream s) throws 1737 IOException { 1738 if (getClass().getClassLoader() != null) { 1739 throw new SecurityException ("invalid address type"); 1740 } 1741 PutField pf = s.putFields(); 1742 pf.put("hostName", holder().getHostName()); 1743 pf.put("address", holder().getAddress()); 1744 pf.put("family", holder().getFamily()); 1745 s.writeFields(); 1746 } 1747 } 1748 1749 /* 1750 * Simple factory to create the impl 1751 */ 1752 class InetAddressImplFactory { 1753 1754 static InetAddressImpl create() { 1755 return InetAddress.loadImpl(isIPv6Supported() ? 1756 "Inet6AddressImpl" : "Inet4AddressImpl"); 1757 } 1758 1759 static native boolean isIPv6Supported(); 1760 }