Java tutorial
/* * Copyright (C) 2008 The Guava Authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.google.common.net; import com.google.common.annotations.Beta; import com.google.common.base.MoreObjects; import com.google.common.base.Preconditions; import com.google.common.hash.Hashing; import com.google.common.io.ByteStreams; import com.google.common.primitives.Ints; import java.net.Inet4Address; import java.net.Inet6Address; import java.net.InetAddress; import java.net.UnknownHostException; import java.nio.ByteBuffer; import java.util.Arrays; import java.util.Locale; import javax.annotation.Nullable; /** * Static utility methods pertaining to {@link InetAddress} instances. * * <p><b>Important note:</b> Unlike {@code InetAddress.getByName()}, the * methods of this class never cause DNS services to be accessed. For * this reason, you should prefer these methods as much as possible over * their JDK equivalents whenever you are expecting to handle only * IP address string literals -- there is no blocking DNS penalty for a * malformed string. * * <p>When dealing with {@link Inet4Address} and {@link Inet6Address} * objects as byte arrays (vis. {@code InetAddress.getAddress()}) they * are 4 and 16 bytes in length, respectively, and represent the address * in network byte order. * * <p>Examples of IP addresses and their byte representations: * <ul> * <li>The IPv4 loopback address, {@code "127.0.0.1"}.<br/> * {@code 7f 00 00 01} * * <li>The IPv6 loopback address, {@code "::1"}.<br/> * {@code 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01} * * <li>From the IPv6 reserved documentation prefix ({@code 2001:db8::/32}), * {@code "2001:db8::1"}.<br/> * {@code 20 01 0d b8 00 00 00 00 00 00 00 00 00 00 00 01} * * <li>An IPv6 "IPv4 compatible" (or "compat") address, * {@code "::192.168.0.1"}.<br/> * {@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01} * * <li>An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.<br/> * {@code 00 00 00 00 00 00 00 00 00 00 ff ff c0 a8 00 01} * </ul> * * <p>A few notes about IPv6 "IPv4 mapped" addresses and their observed * use in Java. * <br><br> * "IPv4 mapped" addresses were originally a representation of IPv4 * addresses for use on an IPv6 socket that could receive both IPv4 * and IPv6 connections (by disabling the {@code IPV6_V6ONLY} socket * option on an IPv6 socket). Yes, it's confusing. Nevertheless, * these "mapped" addresses were never supposed to be seen on the * wire. That assumption was dropped, some say mistakenly, in later * RFCs with the apparent aim of making IPv4-to-IPv6 transition simpler. * * <p>Technically one <i>can</i> create a 128bit IPv6 address with the wire * format of a "mapped" address, as shown above, and transmit it in an * IPv6 packet header. However, Java's InetAddress creation methods * appear to adhere doggedly to the original intent of the "mapped" * address: all "mapped" addresses return {@link Inet4Address} objects. * * <p>For added safety, it is common for IPv6 network operators to filter * all packets where either the source or destination address appears to * be a "compat" or "mapped" address. Filtering suggestions usually * recommend discarding any packets with source or destination addresses * in the invalid range {@code ::/3}, which includes both of these bizarre * address formats. For more information on "bogons", including lists * of IPv6 bogon space, see: * * <ul> * <li><a target="_parent" * href="http://en.wikipedia.org/wiki/Bogon_filtering" * >http://en.wikipedia.org/wiki/Bogon_filtering</a> * <li><a target="_parent" * href="http://www.cymru.com/Bogons/ipv6.txt" * >http://www.cymru.com/Bogons/ipv6.txt</a> * <li><a target="_parent" * href="http://www.cymru.com/Bogons/v6bogon.html" * >http://www.cymru.com/Bogons/v6bogon.html</a> * <li><a target="_parent" * href="http://www.space.net/~gert/RIPE/ipv6-filters.html" * >http://www.space.net/~gert/RIPE/ipv6-filters.html</a> * </ul> * * @author Erik Kline * @since 5.0 */ @Beta public final class InetAddresses { private static final int IPV4_PART_COUNT = 4; private static final int IPV6_PART_COUNT = 8; private static final Inet4Address LOOPBACK4 = (Inet4Address) forString("127.0.0.1"); private static final Inet4Address ANY4 = (Inet4Address) forString("0.0.0.0"); private InetAddresses() { } /** * Returns an {@link Inet4Address}, given a byte array representation of the IPv4 address. * * @param bytes byte array representing an IPv4 address (should be of length 4) * @return {@link Inet4Address} corresponding to the supplied byte array * @throws IllegalArgumentException if a valid {@link Inet4Address} can not be created */ private static Inet4Address getInet4Address(byte[] bytes) { Preconditions.checkArgument(bytes.length == 4, "Byte array has invalid length for an IPv4 address: %s != 4.", bytes.length); // Given a 4-byte array, this cast should always succeed. return (Inet4Address) bytesToInetAddress(bytes); } /** * Returns the {@link InetAddress} having the given string representation. * * <p>This deliberately avoids all nameservice lookups (e.g. no DNS). * * @param ipString {@code String} containing an IPv4 or IPv6 string literal, e.g. * {@code "192.168.0.1"} or {@code "2001:db8::1"} * @return {@link InetAddress} representing the argument * @throws IllegalArgumentException if the argument is not a valid IP string literal */ public static InetAddress forString(String ipString) { byte[] addr = ipStringToBytes(ipString); // The argument was malformed, i.e. not an IP string literal. if (addr == null) { throw formatIllegalArgumentException("'%s' is not an IP string literal.", ipString); } return bytesToInetAddress(addr); } /** * Returns {@code true} if the supplied string is a valid IP string * literal, {@code false} otherwise. * * @param ipString {@code String} to evaluated as an IP string literal * @return {@code true} if the argument is a valid IP string literal */ public static boolean isInetAddress(String ipString) { return ipStringToBytes(ipString) != null; } private static byte[] ipStringToBytes(String ipString) { // Make a first pass to categorize the characters in this string. boolean hasColon = false; boolean hasDot = false; for (int i = 0; i < ipString.length(); i++) { char c = ipString.charAt(i); if (c == '.') { hasDot = true; } else if (c == ':') { if (hasDot) { return null; // Colons must not appear after dots. } hasColon = true; } else if (Character.digit(c, 16) == -1) { return null; // Everything else must be a decimal or hex digit. } } // Now decide which address family to parse. if (hasColon) { if (hasDot) { ipString = convertDottedQuadToHex(ipString); if (ipString == null) { return null; } } return textToNumericFormatV6(ipString); } else if (hasDot) { return textToNumericFormatV4(ipString); } return null; } private static byte[] textToNumericFormatV4(String ipString) { String[] address = ipString.split("\\.", IPV4_PART_COUNT + 1); if (address.length != IPV4_PART_COUNT) { return null; } byte[] bytes = new byte[IPV4_PART_COUNT]; try { for (int i = 0; i < bytes.length; i++) { bytes[i] = parseOctet(address[i]); } } catch (NumberFormatException ex) { return null; } return bytes; } private static byte[] textToNumericFormatV6(String ipString) { // An address can have [2..8] colons, and N colons make N+1 parts. String[] parts = ipString.split(":", IPV6_PART_COUNT + 2); if (parts.length < 3 || parts.length > IPV6_PART_COUNT + 1) { return null; } // Disregarding the endpoints, find "::" with nothing in between. // This indicates that a run of zeroes has been skipped. int skipIndex = -1; for (int i = 1; i < parts.length - 1; i++) { if (parts[i].length() == 0) { if (skipIndex >= 0) { return null; // Can't have more than one :: } skipIndex = i; } } int partsHi; // Number of parts to copy from above/before the "::" int partsLo; // Number of parts to copy from below/after the "::" if (skipIndex >= 0) { // If we found a "::", then check if it also covers the endpoints. partsHi = skipIndex; partsLo = parts.length - skipIndex - 1; if (parts[0].length() == 0 && --partsHi != 0) { return null; // ^: requires ^:: } if (parts[parts.length - 1].length() == 0 && --partsLo != 0) { return null; // :$ requires ::$ } } else { // Otherwise, allocate the entire address to partsHi. The endpoints // could still be empty, but parseHextet() will check for that. partsHi = parts.length; partsLo = 0; } // If we found a ::, then we must have skipped at least one part. // Otherwise, we must have exactly the right number of parts. int partsSkipped = IPV6_PART_COUNT - (partsHi + partsLo); if (!(skipIndex >= 0 ? partsSkipped >= 1 : partsSkipped == 0)) { return null; } // Now parse the hextets into a byte array. ByteBuffer rawBytes = ByteBuffer.allocate(2 * IPV6_PART_COUNT); try { for (int i = 0; i < partsHi; i++) { rawBytes.putShort(parseHextet(parts[i])); } for (int i = 0; i < partsSkipped; i++) { rawBytes.putShort((short) 0); } for (int i = partsLo; i > 0; i--) { rawBytes.putShort(parseHextet(parts[parts.length - i])); } } catch (NumberFormatException ex) { return null; } return rawBytes.array(); } private static String convertDottedQuadToHex(String ipString) { int lastColon = ipString.lastIndexOf(':'); String initialPart = ipString.substring(0, lastColon + 1); String dottedQuad = ipString.substring(lastColon + 1); byte[] quad = textToNumericFormatV4(dottedQuad); if (quad == null) { return null; } String penultimate = Integer.toHexString(((quad[0] & 0xff) << 8) | (quad[1] & 0xff)); String ultimate = Integer.toHexString(((quad[2] & 0xff) << 8) | (quad[3] & 0xff)); return initialPart + penultimate + ":" + ultimate; } private static byte parseOctet(String ipPart) { // Note: we already verified that this string contains only hex digits. int octet = Integer.parseInt(ipPart); // Disallow leading zeroes, because no clear standard exists on // whether these should be interpreted as decimal or octal. if (octet > 255 || (ipPart.startsWith("0") && ipPart.length() > 1)) { throw new NumberFormatException(); } return (byte) octet; } private static short parseHextet(String ipPart) { // Note: we already verified that this string contains only hex digits. int hextet = Integer.parseInt(ipPart, 16); if (hextet > 0xffff) { throw new NumberFormatException(); } return (short) hextet; } /** * Convert a byte array into an InetAddress. * * {@link InetAddress#getByAddress} is documented as throwing a checked * exception "if IP address is of illegal length." We replace it with * an unchecked exception, for use by callers who already know that addr * is an array of length 4 or 16. * * @param addr the raw 4-byte or 16-byte IP address in big-endian order * @return an InetAddress object created from the raw IP address */ private static InetAddress bytesToInetAddress(byte[] addr) { try { return InetAddress.getByAddress(addr); } catch (UnknownHostException e) { throw new AssertionError(e); } } /** * Returns the string representation of an {@link InetAddress}. * * <p>For IPv4 addresses, this is identical to * {@link InetAddress#getHostAddress()}, but for IPv6 addresses, the output * follows <a href="http://tools.ietf.org/html/rfc5952">RFC 5952</a> * section 4. The main difference is that this method uses "::" for zero * compression, while Java's version uses the uncompressed form. * * <p>This method uses hexadecimal for all IPv6 addresses, including * IPv4-mapped IPv6 addresses such as "::c000:201". The output does not * include a Scope ID. * * @param ip {@link InetAddress} to be converted to an address string * @return {@code String} containing the text-formatted IP address * @since 10.0 */ public static String toAddrString(InetAddress ip) { Preconditions.checkNotNull(ip); if (ip instanceof Inet4Address) { // For IPv4, Java's formatting is good enough. return ip.getHostAddress(); } Preconditions.checkArgument(ip instanceof Inet6Address); byte[] bytes = ip.getAddress(); int[] hextets = new int[IPV6_PART_COUNT]; for (int i = 0; i < hextets.length; i++) { hextets[i] = Ints.fromBytes((byte) 0, (byte) 0, bytes[2 * i], bytes[2 * i + 1]); } compressLongestRunOfZeroes(hextets); return hextetsToIPv6String(hextets); } /** * Identify and mark the longest run of zeroes in an IPv6 address. * * <p>Only runs of two or more hextets are considered. In case of a tie, the * leftmost run wins. If a qualifying run is found, its hextets are replaced * by the sentinel value -1. * * @param hextets {@code int[]} mutable array of eight 16-bit hextets */ private static void compressLongestRunOfZeroes(int[] hextets) { int bestRunStart = -1; int bestRunLength = -1; int runStart = -1; for (int i = 0; i < hextets.length + 1; i++) { if (i < hextets.length && hextets[i] == 0) { if (runStart < 0) { runStart = i; } } else if (runStart >= 0) { int runLength = i - runStart; if (runLength > bestRunLength) { bestRunStart = runStart; bestRunLength = runLength; } runStart = -1; } } if (bestRunLength >= 2) { Arrays.fill(hextets, bestRunStart, bestRunStart + bestRunLength, -1); } } /** * Convert a list of hextets into a human-readable IPv6 address. * * <p>In order for "::" compression to work, the input should contain negative * sentinel values in place of the elided zeroes. * * @param hextets {@code int[]} array of eight 16-bit hextets, or -1s */ private static String hextetsToIPv6String(int[] hextets) { /* * While scanning the array, handle these state transitions: * start->num => "num" start->gap => "::" * num->num => ":num" num->gap => "::" * gap->num => "num" gap->gap => "" */ StringBuilder buf = new StringBuilder(39); boolean lastWasNumber = false; for (int i = 0; i < hextets.length; i++) { boolean thisIsNumber = hextets[i] >= 0; if (thisIsNumber) { if (lastWasNumber) { buf.append(':'); } buf.append(Integer.toHexString(hextets[i])); } else { if (i == 0 || lastWasNumber) { buf.append("::"); } } lastWasNumber = thisIsNumber; } return buf.toString(); } /** * Returns the string representation of an {@link InetAddress} suitable * for inclusion in a URI. * * <p>For IPv4 addresses, this is identical to * {@link InetAddress#getHostAddress()}, but for IPv6 addresses it * compresses zeroes and surrounds the text with square brackets; for example * {@code "[2001:db8::1]"}. * * <p>Per section 3.2.2 of * <a target="_parent" * href="http://tools.ietf.org/html/rfc3986#section-3.2.2" * >http://tools.ietf.org/html/rfc3986</a>, * a URI containing an IPv6 string literal is of the form * {@code "http://[2001:db8::1]:8888/index.html"}. * * <p>Use of either {@link InetAddresses#toAddrString}, * {@link InetAddress#getHostAddress()}, or this method is recommended over * {@link InetAddress#toString()} when an IP address string literal is * desired. This is because {@link InetAddress#toString()} prints the * hostname and the IP address string joined by a "/". * * @param ip {@link InetAddress} to be converted to URI string literal * @return {@code String} containing URI-safe string literal */ public static String toUriString(InetAddress ip) { if (ip instanceof Inet6Address) { return "[" + toAddrString(ip) + "]"; } return toAddrString(ip); } /** * Returns an InetAddress representing the literal IPv4 or IPv6 host * portion of a URL, encoded in the format specified by RFC 3986 section 3.2.2. * * <p>This function is similar to {@link InetAddresses#forString(String)}, * however, it requires that IPv6 addresses are surrounded by square brackets. * * <p>This function is the inverse of * {@link InetAddresses#toUriString(java.net.InetAddress)}. * * @param hostAddr A RFC 3986 section 3.2.2 encoded IPv4 or IPv6 address * @return an InetAddress representing the address in {@code hostAddr} * @throws IllegalArgumentException if {@code hostAddr} is not a valid * IPv4 address, or IPv6 address surrounded by square brackets */ public static InetAddress forUriString(String hostAddr) { Preconditions.checkNotNull(hostAddr); // Decide if this should be an IPv6 or IPv4 address. String ipString; int expectBytes; if (hostAddr.startsWith("[") && hostAddr.endsWith("]")) { ipString = hostAddr.substring(1, hostAddr.length() - 1); expectBytes = 16; } else { ipString = hostAddr; expectBytes = 4; } // Parse the address, and make sure the length/version is correct. byte[] addr = ipStringToBytes(ipString); if (addr == null || addr.length != expectBytes) { throw formatIllegalArgumentException("Not a valid URI IP literal: '%s'", hostAddr); } return bytesToInetAddress(addr); } /** * Returns {@code true} if the supplied string is a valid URI IP string * literal, {@code false} otherwise. * * @param ipString {@code String} to evaluated as an IP URI host string literal * @return {@code true} if the argument is a valid IP URI host */ public static boolean isUriInetAddress(String ipString) { try { forUriString(ipString); return true; } catch (IllegalArgumentException e) { return false; } } /** * Evaluates whether the argument is an IPv6 "compat" address. * * <p>An "IPv4 compatible", or "compat", address is one with 96 leading * bits of zero, with the remaining 32 bits interpreted as an * IPv4 address. These are conventionally represented in string * literals as {@code "::192.168.0.1"}, though {@code "::c0a8:1"} is * also considered an IPv4 compatible address (and equivalent to * {@code "::192.168.0.1"}). * * <p>For more on IPv4 compatible addresses see section 2.5.5.1 of * <a target="_parent" * href="http://tools.ietf.org/html/rfc4291#section-2.5.5.1" * >http://tools.ietf.org/html/rfc4291</a> * * <p>NOTE: This method is different from * {@link Inet6Address#isIPv4CompatibleAddress} in that it more * correctly classifies {@code "::"} and {@code "::1"} as * proper IPv6 addresses (which they are), NOT IPv4 compatible * addresses (which they are generally NOT considered to be). * * @param ip {@link Inet6Address} to be examined for embedded IPv4 compatible address format * @return {@code true} if the argument is a valid "compat" address */ public static boolean isCompatIPv4Address(Inet6Address ip) { if (!ip.isIPv4CompatibleAddress()) { return false; } byte[] bytes = ip.getAddress(); if ((bytes[12] == 0) && (bytes[13] == 0) && (bytes[14] == 0) && ((bytes[15] == 0) || (bytes[15] == 1))) { return false; } return true; } /** * Returns the IPv4 address embedded in an IPv4 compatible address. * * @param ip {@link Inet6Address} to be examined for an embedded IPv4 address * @return {@link Inet4Address} of the embedded IPv4 address * @throws IllegalArgumentException if the argument is not a valid IPv4 compatible address */ public static Inet4Address getCompatIPv4Address(Inet6Address ip) { Preconditions.checkArgument(isCompatIPv4Address(ip), "Address '%s' is not IPv4-compatible.", toAddrString(ip)); return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 12, 16)); } /** * Evaluates whether the argument is a 6to4 address. * * <p>6to4 addresses begin with the {@code "2002::/16"} prefix. * The next 32 bits are the IPv4 address of the host to which * IPv6-in-IPv4 tunneled packets should be routed. * * <p>For more on 6to4 addresses see section 2 of * <a target="_parent" href="http://tools.ietf.org/html/rfc3056#section-2" * >http://tools.ietf.org/html/rfc3056</a> * * @param ip {@link Inet6Address} to be examined for 6to4 address format * @return {@code true} if the argument is a 6to4 address */ public static boolean is6to4Address(Inet6Address ip) { byte[] bytes = ip.getAddress(); return (bytes[0] == (byte) 0x20) && (bytes[1] == (byte) 0x02); } /** * Returns the IPv4 address embedded in a 6to4 address. * * @param ip {@link Inet6Address} to be examined for embedded IPv4 in 6to4 address * @return {@link Inet4Address} of embedded IPv4 in 6to4 address * @throws IllegalArgumentException if the argument is not a valid IPv6 6to4 address */ public static Inet4Address get6to4IPv4Address(Inet6Address ip) { Preconditions.checkArgument(is6to4Address(ip), "Address '%s' is not a 6to4 address.", toAddrString(ip)); return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 2, 6)); } /** * A simple immutable data class to encapsulate the information to be found in a * Teredo address. * * <p>All of the fields in this class are encoded in various portions * of the IPv6 address as part of the protocol. More protocols details * can be found at: * <a target="_parent" href="http://en.wikipedia.org/wiki/Teredo_tunneling" * >http://en.wikipedia.org/wiki/Teredo_tunneling</a>. * * <p>The RFC can be found here: * <a target="_parent" href="http://tools.ietf.org/html/rfc4380" * >http://tools.ietf.org/html/rfc4380</a>. * * @since 5.0 */ @Beta public static final class TeredoInfo { private final Inet4Address server; private final Inet4Address client; private final int port; private final int flags; /** * Constructs a TeredoInfo instance. * * <p>Both server and client can be {@code null}, in which case the * value {@code "0.0.0.0"} will be assumed. * * @throws IllegalArgumentException if either of the {@code port} or the {@code flags} * arguments are out of range of an unsigned short */ // TODO: why is this public? public TeredoInfo(@Nullable Inet4Address server, @Nullable Inet4Address client, int port, int flags) { Preconditions.checkArgument((port >= 0) && (port <= 0xffff), "port '%s' is out of range (0 <= port <= 0xffff)", port); Preconditions.checkArgument((flags >= 0) && (flags <= 0xffff), "flags '%s' is out of range (0 <= flags <= 0xffff)", flags); this.server = MoreObjects.firstNonNull(server, ANY4); this.client = MoreObjects.firstNonNull(client, ANY4); this.port = port; this.flags = flags; } public Inet4Address getServer() { return server; } public Inet4Address getClient() { return client; } public int getPort() { return port; } public int getFlags() { return flags; } } /** * Evaluates whether the argument is a Teredo address. * * <p>Teredo addresses begin with the {@code "2001::/32"} prefix. * * @param ip {@link Inet6Address} to be examined for Teredo address format * @return {@code true} if the argument is a Teredo address */ public static boolean isTeredoAddress(Inet6Address ip) { byte[] bytes = ip.getAddress(); return (bytes[0] == (byte) 0x20) && (bytes[1] == (byte) 0x01) && (bytes[2] == 0) && (bytes[3] == 0); } /** * Returns the Teredo information embedded in a Teredo address. * * @param ip {@link Inet6Address} to be examined for embedded Teredo information * @return extracted {@code TeredoInfo} * @throws IllegalArgumentException if the argument is not a valid IPv6 Teredo address */ public static TeredoInfo getTeredoInfo(Inet6Address ip) { Preconditions.checkArgument(isTeredoAddress(ip), "Address '%s' is not a Teredo address.", toAddrString(ip)); byte[] bytes = ip.getAddress(); Inet4Address server = getInet4Address(Arrays.copyOfRange(bytes, 4, 8)); int flags = ByteStreams.newDataInput(bytes, 8).readShort() & 0xffff; // Teredo obfuscates the mapped client port, per section 4 of the RFC. int port = ~ByteStreams.newDataInput(bytes, 10).readShort() & 0xffff; byte[] clientBytes = Arrays.copyOfRange(bytes, 12, 16); for (int i = 0; i < clientBytes.length; i++) { // Teredo obfuscates the mapped client IP, per section 4 of the RFC. clientBytes[i] = (byte) ~clientBytes[i]; } Inet4Address client = getInet4Address(clientBytes); return new TeredoInfo(server, client, port, flags); } /** * Evaluates whether the argument is an ISATAP address. * * <p>From RFC 5214: "ISATAP interface identifiers are constructed in * Modified EUI-64 format [...] by concatenating the 24-bit IANA OUI * (00-00-5E), the 8-bit hexadecimal value 0xFE, and a 32-bit IPv4 * address in network byte order [...]" * * <p>For more on ISATAP addresses see section 6.1 of * <a target="_parent" href="http://tools.ietf.org/html/rfc5214#section-6.1" * >http://tools.ietf.org/html/rfc5214</a> * * @param ip {@link Inet6Address} to be examined for ISATAP address format * @return {@code true} if the argument is an ISATAP address */ public static boolean isIsatapAddress(Inet6Address ip) { // If it's a Teredo address with the right port (41217, or 0xa101) // which would be encoded as 0x5efe then it can't be an ISATAP address. if (isTeredoAddress(ip)) { return false; } byte[] bytes = ip.getAddress(); if ((bytes[8] | (byte) 0x03) != (byte) 0x03) { // Verify that high byte of the 64 bit identifier is zero, modulo // the U/L and G bits, with which we are not concerned. return false; } return (bytes[9] == (byte) 0x00) && (bytes[10] == (byte) 0x5e) && (bytes[11] == (byte) 0xfe); } /** * Returns the IPv4 address embedded in an ISATAP address. * * @param ip {@link Inet6Address} to be examined for embedded IPv4 in ISATAP address * @return {@link Inet4Address} of embedded IPv4 in an ISATAP address * @throws IllegalArgumentException if the argument is not a valid IPv6 ISATAP address */ public static Inet4Address getIsatapIPv4Address(Inet6Address ip) { Preconditions.checkArgument(isIsatapAddress(ip), "Address '%s' is not an ISATAP address.", toAddrString(ip)); return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 12, 16)); } /** * Examines the Inet6Address to determine if it is an IPv6 address of one * of the specified address types that contain an embedded IPv4 address. * * <p>NOTE: ISATAP addresses are explicitly excluded from this method * due to their trivial spoofability. With other transition addresses * spoofing involves (at least) infection of one's BGP routing table. * * @param ip {@link Inet6Address} to be examined for embedded IPv4 client address * @return {@code true} if there is an embedded IPv4 client address * @since 7.0 */ public static boolean hasEmbeddedIPv4ClientAddress(Inet6Address ip) { return isCompatIPv4Address(ip) || is6to4Address(ip) || isTeredoAddress(ip); } /** * Examines the Inet6Address to extract the embedded IPv4 client address * if the InetAddress is an IPv6 address of one of the specified address * types that contain an embedded IPv4 address. * * <p>NOTE: ISATAP addresses are explicitly excluded from this method * due to their trivial spoofability. With other transition addresses * spoofing involves (at least) infection of one's BGP routing table. * * @param ip {@link Inet6Address} to be examined for embedded IPv4 client address * @return {@link Inet4Address} of embedded IPv4 client address * @throws IllegalArgumentException if the argument does not have a valid embedded IPv4 address */ public static Inet4Address getEmbeddedIPv4ClientAddress(Inet6Address ip) { if (isCompatIPv4Address(ip)) { return getCompatIPv4Address(ip); } if (is6to4Address(ip)) { return get6to4IPv4Address(ip); } if (isTeredoAddress(ip)) { return getTeredoInfo(ip).getClient(); } throw formatIllegalArgumentException("'%s' has no embedded IPv4 address.", toAddrString(ip)); } /** * Evaluates whether the argument is an "IPv4 mapped" IPv6 address. * * <p>An "IPv4 mapped" address is anything in the range ::ffff:0:0/96 * (sometimes written as ::ffff:0.0.0.0/96), with the last 32 bits * interpreted as an IPv4 address. * * <p>For more on IPv4 mapped addresses see section 2.5.5.2 of * <a target="_parent" * href="http://tools.ietf.org/html/rfc4291#section-2.5.5.2" * >http://tools.ietf.org/html/rfc4291</a> * * <p>Note: This method takes a {@code String} argument because * {@link InetAddress} automatically collapses mapped addresses to IPv4. * (It is actually possible to avoid this using one of the obscure * {@link Inet6Address} methods, but it would be unwise to depend on such * a poorly-documented feature.) * * @param ipString {@code String} to be examined for embedded IPv4-mapped IPv6 address format * @return {@code true} if the argument is a valid "mapped" address * @since 10.0 */ public static boolean isMappedIPv4Address(String ipString) { byte[] bytes = ipStringToBytes(ipString); if (bytes != null && bytes.length == 16) { for (int i = 0; i < 10; i++) { if (bytes[i] != 0) { return false; } } for (int i = 10; i < 12; i++) { if (bytes[i] != (byte) 0xff) { return false; } } return true; } return false; } /** * Coerces an IPv6 address into an IPv4 address. * * <p>HACK: As long as applications continue to use IPv4 addresses for * indexing into tables, accounting, et cetera, it may be necessary to * <b>coerce</b> IPv6 addresses into IPv4 addresses. This function does * so by hashing the upper 64 bits into {@code 224.0.0.0/3} * (64 bits into 29 bits). * * <p>A "coerced" IPv4 address is equivalent to itself. * * <p>NOTE: This function is failsafe for security purposes: ALL IPv6 * addresses (except localhost (::1)) are hashed to avoid the security * risk associated with extracting an embedded IPv4 address that might * permit elevated privileges. * * @param ip {@link InetAddress} to "coerce" * @return {@link Inet4Address} represented "coerced" address * @since 7.0 */ public static Inet4Address getCoercedIPv4Address(InetAddress ip) { if (ip instanceof Inet4Address) { return (Inet4Address) ip; } // Special cases: byte[] bytes = ip.getAddress(); boolean leadingBytesOfZero = true; for (int i = 0; i < 15; ++i) { if (bytes[i] != 0) { leadingBytesOfZero = false; break; } } if (leadingBytesOfZero && (bytes[15] == 1)) { return LOOPBACK4; // ::1 } else if (leadingBytesOfZero && (bytes[15] == 0)) { return ANY4; // ::0 } Inet6Address ip6 = (Inet6Address) ip; long addressAsLong = 0; if (hasEmbeddedIPv4ClientAddress(ip6)) { addressAsLong = getEmbeddedIPv4ClientAddress(ip6).hashCode(); } else { // Just extract the high 64 bits (assuming the rest is user-modifiable). addressAsLong = ByteBuffer.wrap(ip6.getAddress(), 0, 8).getLong(); } // Many strategies for hashing are possible. This might suffice for now. int coercedHash = Hashing.murmur3_32().hashLong(addressAsLong).asInt(); // Squash into 224/4 Multicast and 240/4 Reserved space (i.e. 224/3). coercedHash |= 0xe0000000; // Fixup to avoid some "illegal" values. Currently the only potential // illegal value is 255.255.255.255. if (coercedHash == 0xffffffff) { coercedHash = 0xfffffffe; } return getInet4Address(Ints.toByteArray(coercedHash)); } /** * Returns an integer representing an IPv4 address regardless of * whether the supplied argument is an IPv4 address or not. * * <p>IPv6 addresses are <b>coerced</b> to IPv4 addresses before being * converted to integers. * * <p>As long as there are applications that assume that all IP addresses * are IPv4 addresses and can therefore be converted safely to integers * (for whatever purpose) this function can be used to handle IPv6 * addresses as well until the application is suitably fixed. * * <p>NOTE: an IPv6 address coerced to an IPv4 address can only be used * for such purposes as rudimentary identification or indexing into a * collection of real {@link InetAddress}es. They cannot be used as * real addresses for the purposes of network communication. * * @param ip {@link InetAddress} to convert * @return {@code int}, "coerced" if ip is not an IPv4 address * @since 7.0 */ public static int coerceToInteger(InetAddress ip) { return ByteStreams.newDataInput(getCoercedIPv4Address(ip).getAddress()).readInt(); } /** * Returns an Inet4Address having the integer value specified by * the argument. * * @param address {@code int}, the 32bit integer address to be converted * @return {@link Inet4Address} equivalent of the argument */ public static Inet4Address fromInteger(int address) { return getInet4Address(Ints.toByteArray(address)); } /** * Returns an address from a <b>little-endian ordered</b> byte array * (the opposite of what {@link InetAddress#getByAddress} expects). * * <p>IPv4 address byte array must be 4 bytes long and IPv6 byte array * must be 16 bytes long. * * @param addr the raw IP address in little-endian byte order * @return an InetAddress object created from the raw IP address * @throws UnknownHostException if IP address is of illegal length */ public static InetAddress fromLittleEndianByteArray(byte[] addr) throws UnknownHostException { byte[] reversed = new byte[addr.length]; for (int i = 0; i < addr.length; i++) { reversed[i] = addr[addr.length - i - 1]; } return InetAddress.getByAddress(reversed); } /** * Returns a new InetAddress that is one less than the passed in address. * This method works for both IPv4 and IPv6 addresses. * * @param address the InetAddress to decrement * @return a new InetAddress that is one less than the passed in address * @throws IllegalArgumentException if InetAddress is at the beginning of its range * @since 18.0 */ public static InetAddress decrement(InetAddress address) { byte[] addr = address.getAddress(); int i = addr.length - 1; while (i >= 0 && addr[i] == (byte) 0x00) { addr[i] = (byte) 0xff; i--; } Preconditions.checkArgument(i >= 0, "Decrementing %s would wrap.", address); addr[i]--; return bytesToInetAddress(addr); } /** * Returns a new InetAddress that is one more than the passed in address. * This method works for both IPv4 and IPv6 addresses. * * @param address the InetAddress to increment * @return a new InetAddress that is one more than the passed in address * @throws IllegalArgumentException if InetAddress is at the end of its range * @since 10.0 */ public static InetAddress increment(InetAddress address) { byte[] addr = address.getAddress(); int i = addr.length - 1; while (i >= 0 && addr[i] == (byte) 0xff) { addr[i] = 0; i--; } Preconditions.checkArgument(i >= 0, "Incrementing %s would wrap.", address); addr[i]++; return bytesToInetAddress(addr); } /** * Returns true if the InetAddress is either 255.255.255.255 for IPv4 or * ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff for IPv6. * * @return true if the InetAddress is either 255.255.255.255 for IPv4 or * ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff for IPv6 * @since 10.0 */ public static boolean isMaximum(InetAddress address) { byte[] addr = address.getAddress(); for (int i = 0; i < addr.length; i++) { if (addr[i] != (byte) 0xff) { return false; } } return true; } private static IllegalArgumentException formatIllegalArgumentException(String format, Object... args) { return new IllegalArgumentException(String.format(Locale.ROOT, format, args)); } }