com.google.common.net.InetAddresses Maven / Gradle / Ivy
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/*
* 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 static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.MoreObjects;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import com.google.common.hash.Hashing;
import com.google.common.io.ByteStreams;
import com.google.common.primitives.Ints;
import java.math.BigInteger;
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.List;
import java.util.Locale;
import org.checkerframework.checker.nullness.qual.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.
*
*
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 5.0
*/
@Beta
@GwtIncompatible
public final class InetAddresses {
private static final int IPV4_PART_COUNT = 4;
private static final int IPV6_PART_COUNT = 8;
private static final Splitter IPV4_SPLITTER = Splitter.on('.').limit(IPV4_PART_COUNT);
private static final Splitter IPV6_SPLITTER = Splitter.on(':').limit(IPV6_PART_COUNT + 2);
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) {
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.
*
* This deliberately avoids all nameservice lookups (e.g. no DNS).
*
*
Anything after a {@code %} in an IPv6 address is ignored (assumed to be a Scope ID).
*
* @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;
}
/** Returns {@code null} if unable to parse into a {@code byte[]}. */
private static byte @Nullable [] ipStringToBytes(String ipString) {
// Make a first pass to categorize the characters in this string.
boolean hasColon = false;
boolean hasDot = false;
int percentIndex = -1;
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 (c == '%') {
percentIndex = i;
break; // everything after a '%' is ignored (it's a Scope ID): http://superuser.com/a/99753
} 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;
}
}
if (percentIndex != -1) {
ipString = ipString.substring(0, percentIndex);
}
return textToNumericFormatV6(ipString);
} else if (hasDot) {
return textToNumericFormatV4(ipString);
}
return null;
}
private static byte @Nullable [] textToNumericFormatV4(String ipString) {
byte[] bytes = new byte[IPV4_PART_COUNT];
int i = 0;
try {
for (String octet : IPV4_SPLITTER.split(ipString)) {
bytes[i++] = parseOctet(octet);
}
} catch (NumberFormatException ex) {
return null;
}
return i == IPV4_PART_COUNT ? bytes : null;
}
private static byte @Nullable [] textToNumericFormatV6(String ipString) {
// An address can have [2..8] colons, and N colons make N+1 parts.
List parts = IPV6_SPLITTER.splitToList(ipString);
if (parts.size() < 3 || parts.size() > 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.size() - 1; i++) {
if (parts.get(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.size() - skipIndex - 1;
if (parts.get(0).length() == 0 && --partsHi != 0) {
return null; // ^: requires ^::
}
if (Iterables.getLast(parts).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.size();
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.get(i)));
}
for (int i = 0; i < partsSkipped; i++) {
rawBytes.putShort((short) 0);
}
for (int i = partsLo; i > 0; i--) {
rawBytes.putShort(parseHextet(parts.get(parts.size() - i)));
}
} catch (NumberFormatException ex) {
return null;
}
return rawBytes.array();
}
private static @Nullable 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}.
*
*
For IPv4 addresses, this is identical to {@link InetAddress#getHostAddress()}, but for IPv6
* addresses, the output follows RFC 5952 section
* 4. The main difference is that this method uses "::" for zero compression, while Java's version
* uses the uncompressed form.
*
*
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) {
checkNotNull(ip);
if (ip instanceof Inet4Address) {
// For IPv4, Java's formatting is good enough.
return ip.getHostAddress();
}
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.
*
*
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.
*
*
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.
*
*
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]"}.
*
*
Per section 3.2.2 of RFC 3986, a URI containing an IPv6
* string literal is of the form {@code "http://[2001:db8::1]:8888/index.html"}.
*
*
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.
*
*
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) {
InetAddress addr = forUriStringNoThrow(hostAddr);
if (addr == null) {
throw formatIllegalArgumentException("Not a valid URI IP literal: '%s'", hostAddr);
}
return addr;
}
private static @Nullable InetAddress forUriStringNoThrow(String hostAddr) {
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) {
return null;
}
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) {
return forUriStringNoThrow(ipString) != null;
}
/**
* 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 RFC 4291.
*
*
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) {
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.
*
*
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 RFC 3056.
*
* @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) {
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.
*
*
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: RFC
* 4380.
*
* @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.
*
*
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) {
checkArgument(
(port >= 0) && (port <= 0xffff), "port '%s' is out of range (0 <= port <= 0xffff)", port);
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.
*
*
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) {
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.
*
*
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 RFC 5214.
*
* @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) {
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.
*
*
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.
*
*
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.
*
*
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.
*
*
For more on IPv4 mapped addresses see section 2.5.5.2 of RFC 4291.
*
*
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.
*
*
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 64 bits of the IPv6 address into {@code 224.0.0.0/3} (64 bits
* into 29 bits):
*
*
* - If the IPv6 address contains an embedded IPv4 address, the function hashes that.
*
- Otherwise, it hashes the upper 64 bits of the IPv6 address.
*
*
* 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 7.0
*/
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.
*
*
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 7.0
*/
public static int coerceToInteger(InetAddress ip) {
return ByteStreams.newDataInput(getCoercedIPv4Address(ip).getAddress()).readInt();
}
/**
* Returns a BigInteger representing the address.
*
*
Unlike {@code coerceToInteger}, IPv6 addresses are not coerced to IPv4 addresses.
*
* @param address {@link InetAddress} to convert
* @return {@code BigInteger} representation of the address
* @since 28.2
*/
public static BigInteger toBigInteger(InetAddress address) {
return new BigInteger(1, address.getAddress());
}
/**
* 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 the {@code Inet4Address} corresponding to a given {@code BigInteger}.
*
* @param address BigInteger representing the IPv4 address
* @return Inet4Address representation of the given BigInteger
* @throws IllegalArgumentException if the BigInteger is not between 0 and 2^32-1
* @since 28.2
*/
public static Inet4Address fromIPv4BigInteger(BigInteger address) {
return (Inet4Address) fromBigInteger(address, false);
}
/**
* Returns the {@code Inet6Address} corresponding to a given {@code BigInteger}.
*
* @param address BigInteger representing the IPv6 address
* @return Inet6Address representation of the given BigInteger
* @throws IllegalArgumentException if the BigInteger is not between 0 and 2^128-1
* @since 28.2
*/
public static Inet6Address fromIPv6BigInteger(BigInteger address) {
return (Inet6Address) fromBigInteger(address, true);
}
/**
* Converts a BigInteger to either an IPv4 or IPv6 address. If the IP is IPv4, it must be
* constrainted to 32 bits, otherwise it is constrained to 128 bits.
*
* @param address the address represented as a big integer
* @param isIpv6 whether the created address should be IPv4 or IPv6
* @return the BigInteger converted to an address
* @throws IllegalArgumentException if the BigInteger is not between 0 and maximum value for IPv4
* or IPv6 respectively
*/
private static InetAddress fromBigInteger(BigInteger address, boolean isIpv6) {
checkArgument(address.signum() >= 0, "BigInteger must be greater than or equal to 0");
int numBytes = isIpv6 ? 16 : 4;
byte[] addressBytes = address.toByteArray();
byte[] targetCopyArray = new byte[numBytes];
int srcPos = Math.max(0, addressBytes.length - numBytes);
int copyLength = addressBytes.length - srcPos;
int destPos = numBytes - copyLength;
// Check the extra bytes in the BigInteger are all zero.
for (int i = 0; i < srcPos; i++) {
if (addressBytes[i] != 0x00) {
throw formatIllegalArgumentException(
"BigInteger cannot be converted to InetAddress because it has more than %d"
+ " bytes: %s",
numBytes, address);
}
}
// Copy the bytes into the least significant positions.
System.arraycopy(addressBytes, srcPos, targetCopyArray, destPos, copyLength);
try {
return InetAddress.getByAddress(targetCopyArray);
} catch (UnknownHostException impossible) {
throw new AssertionError(impossible);
}
}
/**
* 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);
}
/**
* 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--;
}
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--;
}
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));
}
}