/*
* 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 org.elasticsearch.common.network;
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;
public class InetAddresses {
private static int IPV4_PART_COUNT = 4;
private static int IPV6_PART_COUNT = 8;
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 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[] 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 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 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 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;
}
/**
* 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 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) {
if (ip == null) {
throw new NullPointerException("ip");
}
if (ip instanceof Inet4Address) {
// For IPv4, Java's formatting is good enough.
byte[] bytes = ip.getAddress();
return (bytes[0] & 0xff) + "." + (bytes[1] & 0xff) + "." + (bytes[2] & 0xff) + "." + (bytes[3] & 0xff);
}
if (!(ip instanceof Inet6Address)) {
throw new IllegalArgumentException("ip");
}
byte[] bytes = ip.getAddress();
int[] hextets = new int[IPV6_PART_COUNT];
for (int i = 0; i < hextets.length; i++) {
hextets[i] = (bytes[2 * i] & 255) << 8 | bytes[2 * i + 1] & 255;
}
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 {@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 new IllegalArgumentException(String.format(Locale.ROOT, "'%s' is not an IP string literal.", ipString));
}
return bytesToInetAddress(addr);
}
/**
* 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);
}
}
}