1 /* 2 * Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.net; 27 28 import java.util.NavigableSet; 29 import java.util.ArrayList; 30 import java.util.Objects; 31 import java.util.Scanner; 32 import java.security.AccessController; 33 import java.io.File; 34 import java.io.FileNotFoundException; 35 import java.io.ObjectStreamException; 36 import java.io.ObjectStreamField; 37 import java.io.IOException; 38 import java.io.ObjectInputStream; 39 import java.io.ObjectInputStream.GetField; 40 import java.io.ObjectOutputStream; 41 import java.io.ObjectOutputStream.PutField; 42 import java.lang.annotation.Native; 43 import java.util.concurrent.ConcurrentHashMap; 44 import java.util.concurrent.ConcurrentMap; 45 import java.util.concurrent.ConcurrentSkipListSet; 46 import java.util.concurrent.atomic.AtomicLong; 47 48 import jdk.internal.misc.JavaNetInetAddressAccess; 49 import jdk.internal.misc.SharedSecrets; 50 import sun.security.action.*; 51 import sun.net.InetAddressCachePolicy; 52 import sun.net.util.IPAddressUtil; 53 54 /** 55 * This class represents an Internet Protocol (IP) address. 56 * 57 * <p> An IP address is either a 32-bit or 128-bit unsigned number 58 * used by IP, a lower-level protocol on which protocols like UDP and 59 * TCP are built. The IP address architecture is defined by <a 60 * href="http://www.ietf.org/rfc/rfc790.txt"><i>RFC 790: 61 * Assigned Numbers</i></a>, <a 62 * href="http://www.ietf.org/rfc/rfc1918.txt"> <i>RFC 1918: 63 * Address Allocation for Private Internets</i></a>, <a 64 * href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC 2365: 65 * Administratively Scoped IP Multicast</i></a>, and <a 66 * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP 67 * Version 6 Addressing Architecture</i></a>. An instance of an 68 * InetAddress consists of an IP address and possibly its 69 * corresponding host name (depending on whether it is constructed 70 * with a host name or whether it has already done reverse host name 71 * resolution). 72 * 73 * <h3> Address types </h3> 74 * 75 * <blockquote><table class="borderless"> 76 * <caption style="display:none">Description of unicast and multicast address types</caption> 77 * <tbody> 78 * <tr><th valign=top><i>unicast</i></th> 79 * <td>An identifier for a single interface. A packet sent to 80 * a unicast address is delivered to the interface identified by 81 * that address. 82 * 83 * <p> The Unspecified Address -- Also called anylocal or wildcard 84 * address. It must never be assigned to any node. It indicates the 85 * absence of an address. One example of its use is as the target of 86 * bind, which allows a server to accept a client connection on any 87 * interface, in case the server host has multiple interfaces. 88 * 89 * <p> The <i>unspecified</i> address must not be used as 90 * the destination address of an IP packet. 91 * 92 * <p> The <i>Loopback</i> Addresses -- This is the address 93 * assigned to the loopback interface. Anything sent to this 94 * IP address loops around and becomes IP input on the local 95 * host. This address is often used when testing a 96 * client.</td></tr> 97 * <tr><th valign=top><i>multicast</i></th> 98 * <td>An identifier for a set of interfaces (typically belonging 99 * to different nodes). A packet sent to a multicast address is 100 * delivered to all interfaces identified by that address.</td></tr> 101 * </tbody> 102 * </table></blockquote> 103 * 104 * <h4> IP address scope </h4> 105 * 106 * <p> <i>Link-local</i> addresses are designed to be used for addressing 107 * on a single link for purposes such as auto-address configuration, 108 * neighbor discovery, or when no routers are present. 109 * 110 * <p> <i>Site-local</i> addresses are designed to be used for addressing 111 * inside of a site without the need for a global prefix. 112 * 113 * <p> <i>Global</i> addresses are unique across the internet. 114 * 115 * <h4> Textual representation of IP addresses </h4> 116 * 117 * The textual representation of an IP address is address family specific. 118 * 119 * <p> 120 * 121 * For IPv4 address format, please refer to <A 122 * HREF="Inet4Address.html#format">Inet4Address#format</A>; For IPv6 123 * address format, please refer to <A 124 * HREF="Inet6Address.html#format">Inet6Address#format</A>. 125 * 126 * <P>There is a <a href="doc-files/net-properties.html#Ipv4IPv6">couple of 127 * System Properties</a> affecting how IPv4 and IPv6 addresses are used.</P> 128 * 129 * <h4> Host Name Resolution </h4> 130 * 131 * Host name-to-IP address <i>resolution</i> is accomplished through 132 * the use of a combination of local machine configuration information 133 * and network naming services such as the Domain Name System (DNS) 134 * and Network Information Service(NIS). The particular naming 135 * services(s) being used is by default the local machine configured 136 * one. For any host name, its corresponding IP address is returned. 137 * 138 * <p> <i>Reverse name resolution</i> means that for any IP address, 139 * the host associated with the IP address is returned. 140 * 141 * <p> The InetAddress class provides methods to resolve host names to 142 * their IP addresses and vice versa. 143 * 144 * <h4> InetAddress Caching </h4> 145 * 146 * The InetAddress class has a cache to store successful as well as 147 * unsuccessful host name resolutions. 148 * 149 * <p> By default, when a security manager is installed, in order to 150 * protect against DNS spoofing attacks, 151 * the result of positive host name resolutions are 152 * cached forever. When a security manager is not installed, the default 153 * behavior is to cache entries for a finite (implementation dependent) 154 * period of time. The result of unsuccessful host 155 * name resolution is cached for a very short period of time (10 156 * seconds) to improve performance. 157 * 158 * <p> If the default behavior is not desired, then a Java security property 159 * can be set to a different Time-to-live (TTL) value for positive 160 * caching. Likewise, a system admin can configure a different 161 * negative caching TTL value when needed. 162 * 163 * <p> Two Java security properties control the TTL values used for 164 * positive and negative host name resolution caching: 165 * 166 * <blockquote> 167 * <dl> 168 * <dt><b>networkaddress.cache.ttl</b></dt> 169 * <dd>Indicates the caching policy for successful name lookups from 170 * the name service. The value is specified as an integer to indicate 171 * the number of seconds to cache the successful lookup. The default 172 * setting is to cache for an implementation specific period of time. 173 * <p> 174 * A value of -1 indicates "cache forever". 175 * </dd> 176 * <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt> 177 * <dd>Indicates the caching policy for un-successful name lookups 178 * from the name service. The value is specified as an integer to 179 * indicate the number of seconds to cache the failure for 180 * un-successful lookups. 181 * <p> 182 * A value of 0 indicates "never cache". 183 * A value of -1 indicates "cache forever". 184 * </dd> 185 * </dl> 186 * </blockquote> 187 * 188 * @author Chris Warth 189 * @see java.net.InetAddress#getByAddress(byte[]) 190 * @see java.net.InetAddress#getByAddress(java.lang.String, byte[]) 191 * @see java.net.InetAddress#getAllByName(java.lang.String) 192 * @see java.net.InetAddress#getByName(java.lang.String) 193 * @see java.net.InetAddress#getLocalHost() 194 * @since 1.0 195 */ 196 public 197 class InetAddress implements java.io.Serializable { 198 199 @Native static final int PREFER_IPV4_VALUE = 0; 200 @Native static final int PREFER_IPV6_VALUE = 1; 201 @Native static final int PREFER_SYSTEM_VALUE = 2; 202 203 /** 204 * Specify the address family: Internet Protocol, Version 4 205 * @since 1.4 206 */ 207 @Native static final int IPv4 = 1; 208 209 /** 210 * Specify the address family: Internet Protocol, Version 6 211 * @since 1.4 212 */ 213 @Native static final int IPv6 = 2; 214 215 /* Specify address family preference */ 216 static transient final int preferIPv6Address; 217 218 static class InetAddressHolder { 219 /** 220 * Reserve the original application specified hostname. 221 * 222 * The original hostname is useful for domain-based endpoint 223 * identification (see RFC 2818 and RFC 6125). If an address 224 * was created with a raw IP address, a reverse name lookup 225 * may introduce endpoint identification security issue via 226 * DNS forging. 227 * 228 * Oracle JSSE provider is using this original hostname, via 229 * jdk.internal.misc.JavaNetAccess, for SSL/TLS endpoint identification. 230 * 231 * Note: May define a new public method in the future if necessary. 232 */ 233 String originalHostName; 234 235 InetAddressHolder() {} 236 237 InetAddressHolder(String hostName, int address, int family) { 238 this.originalHostName = hostName; 239 this.hostName = hostName; 240 this.address = address; 241 this.family = family; 242 } 243 244 void init(String hostName, int family) { 245 this.originalHostName = hostName; 246 this.hostName = hostName; 247 if (family != -1) { 248 this.family = family; 249 } 250 } 251 252 String hostName; 253 254 String getHostName() { 255 return hostName; 256 } 257 258 String getOriginalHostName() { 259 return originalHostName; 260 } 261 262 /** 263 * Holds a 32-bit IPv4 address. 264 */ 265 int address; 266 267 int getAddress() { 268 return address; 269 } 270 271 /** 272 * Specifies the address family type, for instance, '1' for IPv4 273 * addresses, and '2' for IPv6 addresses. 274 */ 275 int family; 276 277 int getFamily() { 278 return family; 279 } 280 } 281 282 /* Used to store the serializable fields of InetAddress */ 283 final transient InetAddressHolder holder; 284 285 InetAddressHolder holder() { 286 return holder; 287 } 288 289 /* Used to store the name service provider */ 290 private static transient NameService nameService = null; 291 292 /* Used to store the best available hostname */ 293 private transient String canonicalHostName = null; 294 295 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 296 private static final long serialVersionUID = 3286316764910316507L; 297 298 /* 299 * Load net library into runtime, and perform initializations. 300 */ 301 static { 302 String str = java.security.AccessController.doPrivileged( 303 new GetPropertyAction("java.net.preferIPv6Addresses")); 304 if (str == null) { 305 preferIPv6Address = PREFER_IPV4_VALUE; 306 } else if (str.equalsIgnoreCase("true")) { 307 preferIPv6Address = PREFER_IPV6_VALUE; 308 } else if (str.equalsIgnoreCase("false")) { 309 preferIPv6Address = PREFER_IPV4_VALUE; 310 } else if (str.equalsIgnoreCase("system")) { 311 preferIPv6Address = PREFER_SYSTEM_VALUE; 312 } else { 313 preferIPv6Address = PREFER_IPV4_VALUE; 314 } 315 AccessController.doPrivileged( 316 new java.security.PrivilegedAction<>() { 317 public Void run() { 318 System.loadLibrary("net"); 319 return null; 320 } 321 }); 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 if (canonicalHostName == null) { 625 canonicalHostName = 626 InetAddress.getHostFromNameService(this, true); 627 } 628 return canonicalHostName; 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 String addrString = addrToString(addr); 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 if (hostEntry.contains(addrString)) { 994 host = extractHost(hostEntry, addrString); 995 if (host != null) { 996 break; 997 } 998 } 999 } 1000 } 1001 } catch (FileNotFoundException e) { 1002 throw new UnknownHostException("Unable to resolve address " 1003 + addrString + " as hosts file " + hostsFile 1004 + " not found "); 1005 } 1006 1007 if ((host == null) || (host.equals("")) || (host.equals(" "))) { 1008 throw new UnknownHostException("Requested address " 1009 + addrString 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 assocaited with 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 specfied 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.equals(""))) { 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 * IP Address to host mapping 1108 * use first host alias in list 1109 */ 1110 private String extractHost(String hostEntry, String addrString) { 1111 String[] mapping = hostEntry.split("\\s+"); 1112 String host = null; 1113 1114 if (mapping.length >= 2) { 1115 if (mapping[0].equalsIgnoreCase(addrString)) { 1116 host = mapping[1]; 1117 } 1118 } 1119 return host; 1120 } 1121 } 1122 1123 static final InetAddressImpl impl; 1124 1125 static { 1126 // create the impl 1127 impl = InetAddressImplFactory.create(); 1128 1129 // create name service 1130 nameService = createNameService(); 1131 } 1132 1133 /** 1134 * Create an instance of the NameService interface based on 1135 * the setting of the {@codejdk.net.hosts.file} system property. 1136 * 1137 * <p>The default NameService is the PlatformNameService, which typically 1138 * delegates name and address resolution calls to the underlying 1139 * OS network libraries. 1140 * 1141 * <p> A HostsFileNameService is created if the {@code jdk.net.hosts.file} 1142 * system property is set. If the specified file doesn't exist, the name or 1143 * address lookup will result in an UnknownHostException. Thus, non existent 1144 * hosts file is handled as if the file is empty. 1145 * 1146 * @return a NameService 1147 */ 1148 private static NameService createNameService() { 1149 1150 String hostsFileName = 1151 GetPropertyAction.privilegedGetProperty("jdk.net.hosts.file"); 1152 NameService theNameService; 1153 if (hostsFileName != null) { 1154 theNameService = new HostsFileNameService(hostsFileName); 1155 } else { 1156 theNameService = new PlatformNameService(); 1157 } 1158 return theNameService; 1159 } 1160 1161 /** 1162 * Creates an InetAddress based on the provided host name and IP address. 1163 * No name service is checked for the validity of the address. 1164 * 1165 * <p> The host name can either be a machine name, such as 1166 * "{@code java.sun.com}", or a textual representation of its IP 1167 * address. 1168 * <p> No validity checking is done on the host name either. 1169 * 1170 * <p> If addr specifies an IPv4 address an instance of Inet4Address 1171 * will be returned; otherwise, an instance of Inet6Address 1172 * will be returned. 1173 * 1174 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array 1175 * must be 16 bytes long 1176 * 1177 * @param host the specified host 1178 * @param addr the raw IP address in network byte order 1179 * @return an InetAddress object created from the raw IP address. 1180 * @exception UnknownHostException if IP address is of illegal length 1181 * @since 1.4 1182 */ 1183 public static InetAddress getByAddress(String host, byte[] addr) 1184 throws UnknownHostException { 1185 if (host != null && host.length() > 0 && host.charAt(0) == '[') { 1186 if (host.charAt(host.length()-1) == ']') { 1187 host = host.substring(1, host.length() -1); 1188 } 1189 } 1190 if (addr != null) { 1191 if (addr.length == Inet4Address.INADDRSZ) { 1192 return new Inet4Address(host, addr); 1193 } else if (addr.length == Inet6Address.INADDRSZ) { 1194 byte[] newAddr 1195 = IPAddressUtil.convertFromIPv4MappedAddress(addr); 1196 if (newAddr != null) { 1197 return new Inet4Address(host, newAddr); 1198 } else { 1199 return new Inet6Address(host, addr); 1200 } 1201 } 1202 } 1203 throw new UnknownHostException("addr is of illegal length"); 1204 } 1205 1206 1207 /** 1208 * Determines the IP address of a host, given the host's name. 1209 * 1210 * <p> The host name can either be a machine name, such as 1211 * "{@code java.sun.com}", or a textual representation of its 1212 * IP address. If a literal IP address is supplied, only the 1213 * validity of the address format is checked. 1214 * 1215 * <p> For {@code host} specified in literal IPv6 address, 1216 * either the form defined in RFC 2732 or the literal IPv6 address 1217 * format defined in RFC 2373 is accepted. IPv6 scoped addresses are also 1218 * supported. See <a href="Inet6Address.html#scoped">here</a> for a description of IPv6 1219 * scoped addresses. 1220 * 1221 * <p> If the host is {@code null} then an {@code InetAddress} 1222 * representing an address of the loopback interface is returned. 1223 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1224 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1225 * section 2.5.3. </p> 1226 * 1227 * @param host the specified host, or {@code null}. 1228 * @return an IP address for the given host name. 1229 * @exception UnknownHostException if no IP address for the 1230 * {@code host} could be found, or if a scope_id was specified 1231 * for a global IPv6 address. 1232 * @exception SecurityException if a security manager exists 1233 * and its checkConnect method doesn't allow the operation 1234 */ 1235 public static InetAddress getByName(String host) 1236 throws UnknownHostException { 1237 return InetAddress.getAllByName(host)[0]; 1238 } 1239 1240 // called from deployment cache manager 1241 private static InetAddress getByName(String host, InetAddress reqAddr) 1242 throws UnknownHostException { 1243 return InetAddress.getAllByName(host, reqAddr)[0]; 1244 } 1245 1246 /** 1247 * Given the name of a host, returns an array of its IP addresses, 1248 * based on the configured name service on the system. 1249 * 1250 * <p> The host name can either be a machine name, such as 1251 * "{@code java.sun.com}", or a textual representation of its IP 1252 * address. If a literal IP address is supplied, only the 1253 * validity of the address format is checked. 1254 * 1255 * <p> For {@code host} specified in <i>literal IPv6 address</i>, 1256 * either the form defined in RFC 2732 or the literal IPv6 address 1257 * format defined in RFC 2373 is accepted. A literal IPv6 address may 1258 * also be qualified by appending a scoped zone identifier or scope_id. 1259 * The syntax and usage of scope_ids is described 1260 * <a href="Inet6Address.html#scoped">here</a>. 1261 * <p> If the host is {@code null} then an {@code InetAddress} 1262 * representing an address of the loopback interface is returned. 1263 * See <a href="http://www.ietf.org/rfc/rfc3330.txt">RFC 3330</a> 1264 * section 2 and <a href="http://www.ietf.org/rfc/rfc2373.txt">RFC 2373</a> 1265 * section 2.5.3. </p> 1266 * 1267 * <p> If there is a security manager and {@code host} is not 1268 * null and {@code host.length() } is not equal to zero, the 1269 * security manager's 1270 * {@code checkConnect} method is called 1271 * with the hostname and {@code -1} 1272 * as its arguments to see if the operation is allowed. 1273 * 1274 * @param host the name of the host, or {@code null}. 1275 * @return an array of all the IP addresses for a given host name. 1276 * 1277 * @exception UnknownHostException if no IP address for the 1278 * {@code host} could be found, or if a scope_id was specified 1279 * for a global IPv6 address. 1280 * @exception SecurityException if a security manager exists and its 1281 * {@code checkConnect} method doesn't allow the operation. 1282 * 1283 * @see SecurityManager#checkConnect 1284 */ 1285 public static InetAddress[] getAllByName(String host) 1286 throws UnknownHostException { 1287 return getAllByName(host, null); 1288 } 1289 1290 private static InetAddress[] getAllByName(String host, InetAddress reqAddr) 1291 throws UnknownHostException { 1292 1293 if (host == null || host.length() == 0) { 1294 InetAddress[] ret = new InetAddress[1]; 1295 ret[0] = impl.loopbackAddress(); 1296 return ret; 1297 } 1298 1299 boolean ipv6Expected = false; 1300 if (host.charAt(0) == '[') { 1301 // This is supposed to be an IPv6 literal 1302 if (host.length() > 2 && host.charAt(host.length()-1) == ']') { 1303 host = host.substring(1, host.length() -1); 1304 ipv6Expected = true; 1305 } else { 1306 // This was supposed to be a IPv6 address, but it's not! 1307 throw new UnknownHostException(host + ": invalid IPv6 address"); 1308 } 1309 } 1310 1311 // if host is an IP address, we won't do further lookup 1312 if (Character.digit(host.charAt(0), 16) != -1 1313 || (host.charAt(0) == ':')) { 1314 byte[] addr = null; 1315 int numericZone = -1; 1316 String ifname = null; 1317 // see if it is IPv4 address 1318 addr = IPAddressUtil.textToNumericFormatV4(host); 1319 if (addr == null) { 1320 // This is supposed to be an IPv6 literal 1321 // Check if a numeric or string zone id is present 1322 int pos; 1323 if ((pos=host.indexOf ('%')) != -1) { 1324 numericZone = checkNumericZone (host); 1325 if (numericZone == -1) { /* remainder of string must be an ifname */ 1326 ifname = host.substring (pos+1); 1327 } 1328 } 1329 if ((addr = IPAddressUtil.textToNumericFormatV6(host)) == null && host.contains(":")) { 1330 throw new UnknownHostException(host + ": invalid IPv6 address"); 1331 } 1332 } else if (ipv6Expected) { 1333 // Means an IPv4 litteral between brackets! 1334 throw new UnknownHostException("["+host+"]"); 1335 } 1336 InetAddress[] ret = new InetAddress[1]; 1337 if(addr != null) { 1338 if (addr.length == Inet4Address.INADDRSZ) { 1339 ret[0] = new Inet4Address(null, addr); 1340 } else { 1341 if (ifname != null) { 1342 ret[0] = new Inet6Address(null, addr, ifname); 1343 } else { 1344 ret[0] = new Inet6Address(null, addr, numericZone); 1345 } 1346 } 1347 return ret; 1348 } 1349 } else if (ipv6Expected) { 1350 // We were expecting an IPv6 Litteral, but got something else 1351 throw new UnknownHostException("["+host+"]"); 1352 } 1353 return getAllByName0(host, reqAddr, true, true); 1354 } 1355 1356 /** 1357 * Returns the loopback address. 1358 * <p> 1359 * The InetAddress returned will represent the IPv4 1360 * loopback address, 127.0.0.1, or the IPv6 loopback 1361 * address, ::1. The IPv4 loopback address returned 1362 * is only one of many in the form 127.*.*.* 1363 * 1364 * @return the InetAddress loopback instance. 1365 * @since 1.7 1366 */ 1367 public static InetAddress getLoopbackAddress() { 1368 return impl.loopbackAddress(); 1369 } 1370 1371 1372 /** 1373 * check if the literal address string has %nn appended 1374 * returns -1 if not, or the numeric value otherwise. 1375 * 1376 * %nn may also be a string that represents the displayName of 1377 * a currently available NetworkInterface. 1378 */ 1379 private static int checkNumericZone (String s) throws UnknownHostException { 1380 int percent = s.indexOf ('%'); 1381 int slen = s.length(); 1382 int digit, zone=0; 1383 if (percent == -1) { 1384 return -1; 1385 } 1386 for (int i=percent+1; i<slen; i++) { 1387 char c = s.charAt(i); 1388 if (c == ']') { 1389 if (i == percent+1) { 1390 /* empty per-cent field */ 1391 return -1; 1392 } 1393 break; 1394 } 1395 if ((digit = Character.digit (c, 10)) < 0) { 1396 return -1; 1397 } 1398 zone = (zone * 10) + digit; 1399 } 1400 return zone; 1401 } 1402 1403 private static InetAddress[] getAllByName0 (String host) 1404 throws UnknownHostException 1405 { 1406 return getAllByName0(host, true); 1407 } 1408 1409 /** 1410 * package private so SocketPermission can call it 1411 */ 1412 static InetAddress[] getAllByName0 (String host, boolean check) 1413 throws UnknownHostException { 1414 return getAllByName0 (host, null, check, true); 1415 } 1416 1417 /** 1418 * Designated lookup method. 1419 * 1420 * @param host host name to look up 1421 * @param reqAddr requested address to be the 1st in returned array 1422 * @param check perform security check 1423 * @param useCache use cached value if not expired else always 1424 * perform name service lookup (and cache the result) 1425 * @return array of InetAddress(es) 1426 * @throws UnknownHostException if host name is not found 1427 */ 1428 private static InetAddress[] getAllByName0(String host, 1429 InetAddress reqAddr, 1430 boolean check, 1431 boolean useCache) 1432 throws UnknownHostException { 1433 1434 /* If it gets here it is presumed to be a hostname */ 1435 1436 /* make sure the connection to the host is allowed, before we 1437 * give out a hostname 1438 */ 1439 if (check) { 1440 SecurityManager security = System.getSecurityManager(); 1441 if (security != null) { 1442 security.checkConnect(host, -1); 1443 } 1444 } 1445 1446 // remove expired addresses from cache - expirySet keeps them ordered 1447 // by expiry time so we only need to iterate the prefix of the NavigableSet... 1448 long now = System.nanoTime(); 1449 for (CachedAddresses caddrs : expirySet) { 1450 // compare difference of time instants rather than 1451 // time instants directly, to avoid possible overflow. 1452 // (see System.nanoTime() recommendations...) 1453 if ((caddrs.expiryTime - now) < 0L) { 1454 // ConcurrentSkipListSet uses weakly consistent iterator, 1455 // so removing while iterating is OK... 1456 if (expirySet.remove(caddrs)) { 1457 // ... remove from cache 1458 cache.remove(caddrs.host, caddrs); 1459 } 1460 } else { 1461 // we encountered 1st element that expires in future 1462 break; 1463 } 1464 } 1465 1466 // look-up or remove from cache 1467 Addresses addrs; 1468 if (useCache) { 1469 addrs = cache.get(host); 1470 } else { 1471 addrs = cache.remove(host); 1472 if (addrs != null) { 1473 if (addrs instanceof CachedAddresses) { 1474 // try removing from expirySet too if CachedAddresses 1475 expirySet.remove(addrs); 1476 } 1477 addrs = null; 1478 } 1479 } 1480 1481 if (addrs == null) { 1482 // create a NameServiceAddresses instance which will look up 1483 // the name service and install it within cache... 1484 Addresses oldAddrs = cache.putIfAbsent( 1485 host, 1486 addrs = new NameServiceAddresses(host, reqAddr) 1487 ); 1488 if (oldAddrs != null) { // lost putIfAbsent race 1489 addrs = oldAddrs; 1490 } 1491 } 1492 1493 // ask Addresses to get an array of InetAddress(es) and clone it 1494 return addrs.get().clone(); 1495 } 1496 1497 static InetAddress[] getAddressesFromNameService(String host, InetAddress reqAddr) 1498 throws UnknownHostException 1499 { 1500 InetAddress[] addresses = null; 1501 UnknownHostException ex = null; 1502 1503 try { 1504 addresses = nameService.lookupAllHostAddr(host); 1505 } catch (UnknownHostException uhe) { 1506 if (host.equalsIgnoreCase("localhost")) { 1507 addresses = new InetAddress[] { impl.loopbackAddress() }; 1508 } 1509 else { 1510 ex = uhe; 1511 } 1512 } 1513 1514 if (addresses == null) { 1515 throw ex == null ? new UnknownHostException(host) : ex; 1516 } 1517 1518 // More to do? 1519 if (reqAddr != null && addresses.length > 1 && !addresses[0].equals(reqAddr)) { 1520 // Find it? 1521 int i = 1; 1522 for (; i < addresses.length; i++) { 1523 if (addresses[i].equals(reqAddr)) { 1524 break; 1525 } 1526 } 1527 // Rotate 1528 if (i < addresses.length) { 1529 InetAddress tmp, tmp2 = reqAddr; 1530 for (int j = 0; j < i; j++) { 1531 tmp = addresses[j]; 1532 addresses[j] = tmp2; 1533 tmp2 = tmp; 1534 } 1535 addresses[i] = tmp2; 1536 } 1537 } 1538 1539 return addresses; 1540 } 1541 1542 /** 1543 * Returns an {@code InetAddress} object given the raw IP address . 1544 * The argument is in network byte order: the highest order 1545 * byte of the address is in {@code getAddress()[0]}. 1546 * 1547 * <p> This method doesn't block, i.e. no reverse name service lookup 1548 * is performed. 1549 * 1550 * <p> IPv4 address byte array must be 4 bytes long and IPv6 byte array 1551 * must be 16 bytes long 1552 * 1553 * @param addr the raw IP address in network byte order 1554 * @return an InetAddress object created from the raw IP address. 1555 * @exception UnknownHostException if IP address is of illegal length 1556 * @since 1.4 1557 */ 1558 public static InetAddress getByAddress(byte[] addr) 1559 throws UnknownHostException { 1560 return getByAddress(null, addr); 1561 } 1562 1563 private static final class CachedLocalHost { 1564 final String host; 1565 final InetAddress addr; 1566 final long expiryTime = System.nanoTime() + 5000_000_000L; // now + 5s; 1567 1568 CachedLocalHost(String host, InetAddress addr) { 1569 this.host = host; 1570 this.addr = addr; 1571 } 1572 } 1573 1574 private static volatile CachedLocalHost cachedLocalHost; 1575 1576 /** 1577 * Returns the address of the local host. This is achieved by retrieving 1578 * the name of the host from the system, then resolving that name into 1579 * an {@code InetAddress}. 1580 * 1581 * <P>Note: The resolved address may be cached for a short period of time. 1582 * </P> 1583 * 1584 * <p>If there is a security manager, its 1585 * {@code checkConnect} method is called 1586 * with the local host name and {@code -1} 1587 * as its arguments to see if the operation is allowed. 1588 * If the operation is not allowed, an InetAddress representing 1589 * the loopback address is returned. 1590 * 1591 * @return the address of the local host. 1592 * 1593 * @exception UnknownHostException if the local host name could not 1594 * be resolved into an address. 1595 * 1596 * @see SecurityManager#checkConnect 1597 * @see java.net.InetAddress#getByName(java.lang.String) 1598 */ 1599 public static InetAddress getLocalHost() throws UnknownHostException { 1600 1601 SecurityManager security = System.getSecurityManager(); 1602 try { 1603 // is cached data still valid? 1604 CachedLocalHost clh = cachedLocalHost; 1605 if (clh != null && (clh.expiryTime - System.nanoTime()) >= 0L) { 1606 if (security != null) { 1607 security.checkConnect(clh.host, -1); 1608 } 1609 return clh.addr; 1610 } 1611 1612 String local = impl.getLocalHostName(); 1613 1614 if (security != null) { 1615 security.checkConnect(local, -1); 1616 } 1617 1618 InetAddress localAddr; 1619 if (local.equals("localhost")) { 1620 // shortcut for "localhost" host name 1621 localAddr = impl.loopbackAddress(); 1622 } else { 1623 // call getAllByName0 without security checks and 1624 // without using cached data 1625 try { 1626 localAddr = getAllByName0(local, null, false, false)[0]; 1627 } catch (UnknownHostException uhe) { 1628 // Rethrow with a more informative error message. 1629 UnknownHostException uhe2 = 1630 new UnknownHostException(local + ": " + 1631 uhe.getMessage()); 1632 uhe2.initCause(uhe); 1633 throw uhe2; 1634 } 1635 } 1636 cachedLocalHost = new CachedLocalHost(local, localAddr); 1637 return localAddr; 1638 } catch (java.lang.SecurityException e) { 1639 return impl.loopbackAddress(); 1640 } 1641 } 1642 1643 /** 1644 * Perform class load-time initializations. 1645 */ 1646 private static native void init(); 1647 1648 1649 /* 1650 * Returns the InetAddress representing anyLocalAddress 1651 * (typically 0.0.0.0 or ::0) 1652 */ 1653 static InetAddress anyLocalAddress() { 1654 return impl.anyLocalAddress(); 1655 } 1656 1657 /* 1658 * Load and instantiate an underlying impl class 1659 */ 1660 static InetAddressImpl loadImpl(String implName) { 1661 Object impl = null; 1662 1663 /* 1664 * Property "impl.prefix" will be prepended to the classname 1665 * of the implementation object we instantiate, to which we 1666 * delegate the real work (like native methods). This 1667 * property can vary across implementations of the java. 1668 * classes. The default is an empty String "". 1669 */ 1670 String prefix = GetPropertyAction.privilegedGetProperty("impl.prefix", ""); 1671 try { 1672 @SuppressWarnings("deprecation") 1673 Object tmp = Class.forName("java.net." + prefix + implName).newInstance(); 1674 impl = tmp; 1675 } catch (ClassNotFoundException e) { 1676 System.err.println("Class not found: java.net." + prefix + 1677 implName + ":\ncheck impl.prefix property " + 1678 "in your properties file."); 1679 } catch (InstantiationException e) { 1680 System.err.println("Could not instantiate: java.net." + prefix + 1681 implName + ":\ncheck impl.prefix property " + 1682 "in your properties file."); 1683 } catch (IllegalAccessException e) { 1684 System.err.println("Cannot access class: java.net." + prefix + 1685 implName + ":\ncheck impl.prefix property " + 1686 "in your properties file."); 1687 } 1688 1689 if (impl == null) { 1690 try { 1691 @SuppressWarnings("deprecation") 1692 Object tmp = Class.forName(implName).newInstance(); 1693 impl = tmp; 1694 } catch (Exception e) { 1695 throw new Error("System property impl.prefix incorrect"); 1696 } 1697 } 1698 1699 return (InetAddressImpl) impl; 1700 } 1701 1702 private void readObjectNoData (ObjectInputStream s) throws 1703 IOException, ClassNotFoundException { 1704 if (getClass().getClassLoader() != null) { 1705 throw new SecurityException ("invalid address type"); 1706 } 1707 } 1708 1709 private static final long FIELDS_OFFSET; 1710 private static final jdk.internal.misc.Unsafe UNSAFE; 1711 1712 static { 1713 try { 1714 jdk.internal.misc.Unsafe unsafe = jdk.internal.misc.Unsafe.getUnsafe(); 1715 FIELDS_OFFSET = unsafe.objectFieldOffset( 1716 InetAddress.class.getDeclaredField("holder") 1717 ); 1718 UNSAFE = unsafe; 1719 } catch (ReflectiveOperationException e) { 1720 throw new Error(e); 1721 } 1722 } 1723 1724 private void readObject (ObjectInputStream s) throws 1725 IOException, ClassNotFoundException { 1726 if (getClass().getClassLoader() != null) { 1727 throw new SecurityException ("invalid address type"); 1728 } 1729 GetField gf = s.readFields(); 1730 String host = (String)gf.get("hostName", null); 1731 int address= gf.get("address", 0); 1732 int family= gf.get("family", 0); 1733 InetAddressHolder h = new InetAddressHolder(host, address, family); 1734 UNSAFE.putObject(this, FIELDS_OFFSET, h); 1735 } 1736 1737 /* needed because the serializable fields no longer exist */ 1738 1739 /** 1740 * @serialField hostName String 1741 * @serialField address int 1742 * @serialField family int 1743 */ 1744 private static final ObjectStreamField[] serialPersistentFields = { 1745 new ObjectStreamField("hostName", String.class), 1746 new ObjectStreamField("address", int.class), 1747 new ObjectStreamField("family", int.class), 1748 }; 1749 1750 private void writeObject (ObjectOutputStream s) throws 1751 IOException { 1752 if (getClass().getClassLoader() != null) { 1753 throw new SecurityException ("invalid address type"); 1754 } 1755 PutField pf = s.putFields(); 1756 pf.put("hostName", holder().getHostName()); 1757 pf.put("address", holder().getAddress()); 1758 pf.put("family", holder().getFamily()); 1759 s.writeFields(); 1760 } 1761 } 1762 1763 /* 1764 * Simple factory to create the impl 1765 */ 1766 class InetAddressImplFactory { 1767 1768 static InetAddressImpl create() { 1769 return InetAddress.loadImpl(isIPv6Supported() ? 1770 "Inet6AddressImpl" : "Inet4AddressImpl"); 1771 } 1772 1773 static native boolean isIPv6Supported(); 1774 }