Requests_IPv6

Class to validate and to work with IPv6 addresses


Description Description

This was originally based on the PEAR class of the same name, but has been entirely rewritten.


Source Source

File: wp-includes/Requests/IPv6.php

class Requests_IPv6 {
	/**
	 * Uncompresses an IPv6 address
	 *
	 * RFC 4291 allows you to compress consecutive zero pieces in an address to
	 * '::'. This method expects a valid IPv6 address and expands the '::' to
	 * the required number of zero pieces.
	 *
	 * Example:  FF01::101   ->  FF01:0:0:0:0:0:0:101
	 *           ::1         ->  0:0:0:0:0:0:0:1
	 *
	 * @author Alexander Merz <alexander.merz@web.de>
	 * @author elfrink at introweb dot nl
	 * @author Josh Peck <jmp at joshpeck dot org>
	 * @copyright 2003-2005 The PHP Group
	 * @license http://www.opensource.org/licenses/bsd-license.php
	 * @param string $ip An IPv6 address
	 * @return string The uncompressed IPv6 address
	 */
	public static function uncompress($ip) {
		if (substr_count($ip, '::') !== 1) {
			return $ip;
		}

		list($ip1, $ip2) = explode('::', $ip);
		$c1 = ($ip1 === '') ? -1 : substr_count($ip1, ':');
		$c2 = ($ip2 === '') ? -1 : substr_count($ip2, ':');

		if (strpos($ip2, '.') !== false) {
			$c2++;
		}
		// ::
		if ($c1 === -1 && $c2 === -1) {
			$ip = '0:0:0:0:0:0:0:0';
		}
		// ::xxx
		else if ($c1 === -1) {
			$fill = str_repeat('0:', 7 - $c2);
			$ip = str_replace('::', $fill, $ip);
		}
		// xxx::
		else if ($c2 === -1) {
			$fill = str_repeat(':0', 7 - $c1);
			$ip = str_replace('::', $fill, $ip);
		}
		// xxx::xxx
		else {
			$fill = ':' . str_repeat('0:', 6 - $c2 - $c1);
			$ip = str_replace('::', $fill, $ip);
		}
		return $ip;
	}

	/**
	 * Compresses an IPv6 address
	 *
	 * RFC 4291 allows you to compress consecutive zero pieces in an address to
	 * '::'. This method expects a valid IPv6 address and compresses consecutive
	 * zero pieces to '::'.
	 *
	 * Example:  FF01:0:0:0:0:0:0:101   ->  FF01::101
	 *           0:0:0:0:0:0:0:1        ->  ::1
	 *
	 * @see uncompress()
	 * @param string $ip An IPv6 address
	 * @return string The compressed IPv6 address
	 */
	public static function compress($ip) {
		// Prepare the IP to be compressed
		$ip = self::uncompress($ip);
		$ip_parts = self::split_v6_v4($ip);

		// Replace all leading zeros
		$ip_parts[0] = preg_replace('/(^|:)0+([0-9])/', '\1\2', $ip_parts[0]);

		// Find bunches of zeros
		if (preg_match_all('/(?:^|:)(?:0(?::|$))+/', $ip_parts[0], $matches, PREG_OFFSET_CAPTURE)) {
			$max = 0;
			$pos = null;
			foreach ($matches[0] as $match) {
				if (strlen($match[0]) > $max) {
					$max = strlen($match[0]);
					$pos = $match[1];
				}
			}

			$ip_parts[0] = substr_replace($ip_parts[0], '::', $pos, $max);
		}

		if ($ip_parts[1] !== '') {
			return implode(':', $ip_parts);
		}
		else {
			return $ip_parts[0];
		}
	}

	/**
	 * Splits an IPv6 address into the IPv6 and IPv4 representation parts
	 *
	 * RFC 4291 allows you to represent the last two parts of an IPv6 address
	 * using the standard IPv4 representation
	 *
	 * Example:  0:0:0:0:0:0:13.1.68.3
	 *           0:0:0:0:0:FFFF:129.144.52.38
	 *
	 * @param string $ip An IPv6 address
	 * @return string[] [0] contains the IPv6 represented part, and [1] the IPv4 represented part
	 */
	protected static function split_v6_v4($ip) {
		if (strpos($ip, '.') !== false) {
			$pos = strrpos($ip, ':');
			$ipv6_part = substr($ip, 0, $pos);
			$ipv4_part = substr($ip, $pos + 1);
			return array($ipv6_part, $ipv4_part);
		}
		else {
			return array($ip, '');
		}
	}

	/**
	 * Checks an IPv6 address
	 *
	 * Checks if the given IP is a valid IPv6 address
	 *
	 * @param string $ip An IPv6 address
	 * @return bool true if $ip is a valid IPv6 address
	 */
	public static function check_ipv6($ip) {
		$ip = self::uncompress($ip);
		list($ipv6, $ipv4) = self::split_v6_v4($ip);
		$ipv6 = explode(':', $ipv6);
		$ipv4 = explode('.', $ipv4);
		if (count($ipv6) === 8 && count($ipv4) === 1 || count($ipv6) === 6 && count($ipv4) === 4) {
			foreach ($ipv6 as $ipv6_part) {
				// The section can't be empty
				if ($ipv6_part === '') {
					return false;
				}

				// Nor can it be over four characters
				if (strlen($ipv6_part) > 4) {
					return false;
				}

				// Remove leading zeros (this is safe because of the above)
				$ipv6_part = ltrim($ipv6_part, '0');
				if ($ipv6_part === '') {
					$ipv6_part = '0';
				}

				// Check the value is valid
				$value = hexdec($ipv6_part);
				if (dechex($value) !== strtolower($ipv6_part) || $value < 0 || $value > 0xFFFF) {
					return false;
				}
			}
			if (count($ipv4) === 4) {
				foreach ($ipv4 as $ipv4_part) {
					$value = (int) $ipv4_part;
					if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF) {
						return false;
					}
				}
			}
			return true;
		}
		else {
			return false;
		}
	}
}

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