FF01:0:0:0:0:0:0:101 * ::1 -> 0:0:0:0:0:0:0:1 * * @author Alexander Merz * @author elfrink at introweb dot nl * @author Josh Peck * @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 ( -1 === $c1 && -1 === $c2 ) { $ip = '0:0:0:0:0:0:0:0'; } // ::xxx elseif ( -1 === $c1 ) { $fill = str_repeat( '0:', 7 - $c2 ); $ip = str_replace( '::', $fill, $ip ); } // xxx:: elseif ( -1 === $c2 ) { $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; } } }