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/*
* Copyright (C) 2008 Google Inc.
*
* 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.Preconditions;
import com.google.common.io.ByteStreams;
import com.google.common.primitives.Ints;
import com.google.common.primitives.Longs;
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.
*
* Important note: 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.
*
*
This class hooks into the {@code sun.net.util.IPAddressUtil} class
* to make use of the {@code textToNumericFormatV4} and
* {@code textToNumericFormatV6} methods directly as a means to avoid
* accidentally traversing all nameservices (it can be vitally important
* to avoid, say, blocking on DNS at times).
*
*
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.
*
*
Examples of IP addresses and their byte representations:
*
* - The IPv4 loopback address, {@code "127.0.0.1"}.
* {@code 7f 00 00 01}
*
* - The IPv6 loopback address, {@code "::1"}.
* {@code 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01}
*
* - From the IPv6 reserved documentation prefix ({@code 2001:db8::/32}),
* {@code "2001:db8::1"}.
* {@code 20 01 0d b8 00 00 00 00 00 00 00 00 00 00 00 01}
*
* - An IPv6 "IPv4 compatible" (or "compat") address,
* {@code "::192.168.0.1"}.
* {@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01}
*
* - An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.
* {@code 00 00 00 00 00 00 00 00 00 00 ff ff c0 a8 00 01}
*
*
* A few notes about IPv6 "IPv4 mapped" addresses and their observed
* use in Java.
*
* "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.
*
*
Technically one can 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.
*
*
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:
*
*
* - http://en.wikipedia.org/wiki/Bogon_filtering
*
- http://www.cymru.com/Bogons/ipv6.txt
*
- http://www.cymru.com/Bogons/v6bogon.html
*
- http://www.space.net/~gert/RIPE/ipv6-filters.html
*
*
* @author Erik Kline
* @since 5
*/
@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);
try {
InetAddress ipv4 = InetAddress.getByAddress(bytes);
if (!(ipv4 instanceof Inet4Address)) {
throw new UnknownHostException(
String.format("'%s' is not an IPv4 address.",
ipv4.getHostAddress()));
}
return (Inet4Address) ipv4;
} catch (UnknownHostException e) {
/*
* This really shouldn't happen in practice since all our byte
* sequences should be valid IP addresses.
*
* However {@link InetAddress#getByAddress} is documented as
* potentially throwing this "if IP address is of illegal length".
*
* This is mapped to IllegalArgumentException since, presumably,
* the argument triggered some bizarre processing bug.
*/
throw new IllegalArgumentException(
String.format("Host address '%s' is not a valid IPv4 address.",
Arrays.toString(bytes)),
e);
}
}
/**
* Returns the {@link InetAddress} having the given string
* representation.
*
* 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 = textToNumericFormatV4(ipString);
if (addr == null) {
// Scanning for IPv4 string literal failed; try IPv6.
addr = textToNumericFormatV6(ipString);
}
// The argument was malformed, i.e. not an IP string literal.
if (addr == null) {
throw new IllegalArgumentException(
String.format("'%s' is not an IP string literal.", ipString));
}
try {
return InetAddress.getByAddress(addr);
} catch (UnknownHostException e) {
/*
* This really shouldn't happen in practice since all our byte
* sequences should be valid IP addresses.
*
* However {@link InetAddress#getByAddress} is documented as
* potentially throwing this "if IP address is of illegal length".
*
* This is mapped to IllegalArgumentException since, presumably,
* the argument triggered some processing bug in either
* {@link IPAddressUtil#textToNumericFormatV4} or
* {@link IPAddressUtil#textToNumericFormatV6}.
*/
throw new IllegalArgumentException(
String.format("'%s' is extremely broken.", ipString), e);
}
}
/**
* 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) {
try {
forString(ipString);
return true;
} catch (IllegalArgumentException e) {
return false;
}
}
private static byte[] textToNumericFormatV4(String ipString) {
boolean isIpv6 = false;
// handle IPv6 forms of IPv4 addresses
// TODO: use Ascii.toUpperCase() when available
if (ipString.toUpperCase(Locale.US).startsWith("::FFFF:")) {
ipString = ipString.substring(7);
} else if (ipString.startsWith("::")) {
ipString = ipString.substring(2);
isIpv6 = true;
}
String[] address = ipString.split("\\.");
if (address.length != IPV4_PART_COUNT) {
return null;
}
try {
byte[] bytes = new byte[IPV4_PART_COUNT];
for (int i = 0; i < bytes.length; i++) {
int piece = Integer.parseInt(address[i]);
if (piece < 0 || piece > 255) {
return null;
}
// No leading zeroes are allowed. See
// http://tools.ietf.org/html/draft-main-ipaddr-text-rep-00
// section 2.1 for discussion.
if (address[i].startsWith("0") && address[i].length() != 1) {
return null;
}
bytes[i] = (byte) piece;
}
if (isIpv6) { // prepend with zeroes;
byte[] data = new byte[2 * IPV6_PART_COUNT]; // Java initializes arrays to zero
System.arraycopy(bytes, 0, data, 12, IPV4_PART_COUNT);
return data;
} else {
return bytes;
}
} catch (NumberFormatException ex) {
return null;
}
}
private static byte[] textToNumericFormatV6(String ipString) {
if (!ipString.contains(":")) {
return null;
}
if (ipString.contains(":::")) {
return null;
}
if (ipString.contains(".")) {
ipString = convertDottedQuadToHex(ipString);
if (ipString == null) {
return null;
}
}
ipString = padIpString(ipString);
try {
String[] address = ipString.split(":", IPV6_PART_COUNT);
if (address.length != IPV6_PART_COUNT) {
return null;
}
byte[] bytes = new byte[2 * IPV6_PART_COUNT];
for (int i = 0; i < IPV6_PART_COUNT; i++) {
int piece = address[i].equals("") ? 0 : Integer.parseInt(address[i], 16);
bytes[2 * i] = (byte) ((piece & 0xFF00) >>> 8);
bytes[2 * i + 1] = (byte) (piece & 0xFF);
}
return bytes;
} catch (NumberFormatException ex) {
return null;
}
}
// Fill in any omitted colons
private static String padIpString(String ipString) {
if (ipString.contains("::")) {
int count = numberOfColons(ipString);
StringBuilder buffer = new StringBuilder("::");
for (int i = 0; i + count < 7; i++) {
buffer.append(":");
}
ipString = ipString.replace("::", buffer);
}
return ipString;
}
private static int numberOfColons(String s) {
int count = 0;
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == ':') {
count++;
}
}
return count;
}
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;
}
/**
* Returns the string representation of an {@link InetAddress} suitable
* for inclusion in a URI.
*
*
For IPv4 addresses, this is identical to
* {@link InetAddress#getHostAddress()}, but for IPv6 addresses it
* surrounds this text with square brackets; for example
* {@code "[2001:db8::1]"}.
*
*
Per section 3.2.2 of
* http://tools.ietf.org/html/rfc3986,
* a URI containing an IPv6 string literal is of the form
* {@code "http://[2001:db8::1]:8888/index.html"}.
*
*
Use of either {@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 "[" + ip.getHostAddress() + "]";
}
return ip.getHostAddress();
}
/**
* 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.
*
*
This function is similar to {@link InetAddresses#forString(String)},
* however, it requires that IPv6 addresses are surrounded by square brackets.
*
*
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);
Preconditions.checkArgument(hostAddr.length() > 0, "host string is empty");
InetAddress retval = null;
// IPv4 address?
try {
retval = forString(hostAddr);
if (retval instanceof Inet4Address) {
return retval;
}
} catch (IllegalArgumentException e) {
// Not a valid IP address, fall through.
}
// IPv6 address
if (!(hostAddr.startsWith("[") && hostAddr.endsWith("]"))) {
throw new IllegalArgumentException("Not a valid address: \"" + hostAddr + '"');
}
retval = forString(hostAddr.substring(1, hostAddr.length() - 1));
if (retval instanceof Inet6Address) {
return retval;
}
throw new IllegalArgumentException("Not a valid address: \"" + hostAddr + '"');
}
/**
* 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.
*
*
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"}).
*
*
For more on IPv4 compatible addresses see section 2.5.5.1 of
* http://tools.ietf.org/html/rfc4291
*
*
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.", ip.getHostAddress());
return getInet4Address(copyOfRange(ip.getAddress(), 12, 16));
}
/**
* Evaluates whether the argument is a 6to4 address.
*
*
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.
*
*
For more on 6to4 addresses see section 2 of
* http://tools.ietf.org/html/rfc3056
*
* @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.", ip.getHostAddress());
return getInet4Address(copyOfRange(ip.getAddress(), 2, 6));
}
/**
* A simple data class to encapsulate the information to be found in a
* Teredo address.
*
*
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:
* http://en.wikipedia.org/wiki/Teredo_tunneling.
*
*
The RFC can be found here:
* http://tools.ietf.org/html/rfc4380.
*
* @since 5
*/
@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.
*
*
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 '%d' is out of range (0 <= port <= 0xffff)", port);
Preconditions.checkArgument((flags >= 0) && (flags <= 0xffff),
"flags '%d' is out of range (0 <= flags <= 0xffff)", flags);
if (server != null) {
this.server = server;
} else {
this.server = ANY4;
}
if (client != null) {
this.client = client;
} else {
this.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.
*
*
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.", ip.getHostAddress());
byte[] bytes = ip.getAddress();
Inet4Address server = getInet4Address(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 = 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.
*
*
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 [...]"
*
*
For more on ISATAP addresses see section 6.1 of
* http://tools.ietf.org/html/rfc5214
*
* @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.", ip.getHostAddress());
return getInet4Address(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.
*
*
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
*/
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.
*
*
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 new IllegalArgumentException(
String.format("'%s' has no embedded IPv4 address.",
ip.getHostAddress()));
}
/**
* Coerces an IPv6 address into an IPv4 address.
*
*
HACK: As long as applications continue to use IPv4 addresses for
* indexing into tables, accounting, et cetera, it may be necessary to
* coerce 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).
*
*
A "coerced" IPv4 address is equivalent to itself.
*
*
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
*/
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 = (long) 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 = Longs.hashCode(addressAsLong);
// 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.
*
*
IPv6 addresses are coerced to IPv4 addresses before being
* converted to integers.
*
*
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.
*
*
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
*/
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 little-endian ordered byte array
* (the opposite of what {@link InetAddress#getByAddress} expects).
*
*
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);
}
/**
* This method emulates the Java 6 method
* {@code Arrays.copyOfRange(byte, int, int)}, which is not available in
* Java 5, and thus cannot be used in Guava code.
*/
private static byte[] copyOfRange(byte[] original, int from, int to) {
Preconditions.checkNotNull(original);
int end = Math.min(to, original.length);
byte[] result = new byte[to - from];
System.arraycopy(original, from, result, 0, end - from);
return result;
}
}