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+<?php
+/*
+ * Collection of public static functions to play with IP address
+ * and IP blocks.
+ *
+ * @Author "Ashar Voultoiz" <hashar@altern.org>
+ * @License GPL v2 or later
+ */
+
+// Some regex definition to "play" with IP address and IP address blocks
+
+// An IP is made of 4 bytes from x00 to xFF which is d0 to d255
+define( 'RE_IP_BYTE', '(25[0-5]|2[0-4]\d|1?\d{1,2})');
+define( 'RE_IP_ADD' , RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE );
+// An IP block is an IP address and a prefix (d1 to d32)
+define( 'RE_IP_PREFIX' , '(3[0-2]|[12]?\d)');
+define( 'RE_IP_BLOCK', RE_IP_ADD . '\/' . RE_IP_PREFIX);
+
+class IP {
+
+ /**
+ * Validate an IP address.
+ * @return boolean True if it is valid.
+ */
+ public static function isValid( $ip ) {
+ return preg_match( '/^' . RE_IP_ADD . '$/', $ip, $matches) ;
+ }
+
+ /**
+ * Validate an IP Block.
+ * @return boolean True if it is valid.
+ */
+ public static function isValidBlock( $ipblock ) {
+ return ( count(self::toArray($ipblock)) == 1 + 5 );
+ }
+
+ /**
+ * Determine if an IP address really is an IP address, and if it is public,
+ * i.e. not RFC 1918 or similar
+ * Comes from ProxyTools.php
+ */
+ public static function isPublic( $ip ) {
+ $n = IP::toUnsigned( $ip );
+ if ( !$n ) {
+ return false;
+ }
+
+ // ip2long accepts incomplete addresses, as well as some addresses
+ // followed by garbage characters. Check that it's really valid.
+ if( $ip != long2ip( $n ) ) {
+ return false;
+ }
+
+ static $privateRanges = false;
+ if ( !$privateRanges ) {
+ $privateRanges = array(
+ array( '10.0.0.0', '10.255.255.255' ), # RFC 1918 (private)
+ array( '172.16.0.0', '172.31.255.255' ), # "
+ array( '192.168.0.0', '192.168.255.255' ), # "
+ array( '0.0.0.0', '0.255.255.255' ), # this network
+ array( '127.0.0.0', '127.255.255.255' ), # loopback
+ );
+ }
+
+ foreach ( $privateRanges as $r ) {
+ $start = IP::toUnsigned( $r[0] );
+ $end = IP::toUnsigned( $r[1] );
+ if ( $n >= $start && $n <= $end ) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ /**
+ * Split out an IP block as an array of 4 bytes and a mask,
+ * return false if it cant be determined
+ *
+ * @parameter $ip string A quad dotted IP address
+ * @return array
+ */
+ public static function toArray( $ipblock ) {
+ if(! preg_match( '/^' . RE_IP_ADD . '(?:\/(?:'.RE_IP_PREFIX.'))?' . '$/', $ipblock, $matches ) ) {
+ return false;
+ } else {
+ return $matches;
+ }
+ }
+
+ /**
+ * Return a zero-padded hexadecimal representation of an IP address.
+ *
+ * Hexadecimal addresses are used because they can easily be extended to
+ * IPv6 support. To separate the ranges, the return value from this
+ * function for an IPv6 address will be prefixed with "v6-", a non-
+ * hexadecimal string which sorts after the IPv4 addresses.
+ *
+ * @param $ip Quad dotted IP address.
+ */
+ public static function toHex( $ip ) {
+ $n = self::toUnsigned( $ip );
+ if ( $n !== false ) {
+ $n = sprintf( '%08X', $n );
+ }
+ return $n;
+ }
+
+ /**
+ * Given an IP address in dotted-quad notation, returns an unsigned integer.
+ * Like ip2long() except that it actually works and has a consistent error return value.
+ * Comes from ProxyTools.php
+ * @param $ip Quad dotted IP address.
+ */
+ public static function toUnsigned( $ip ) {
+ if ( $ip == '255.255.255.255' ) {
+ $n = -1;
+ } else {
+ $n = ip2long( $ip );
+ if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
+ $n = false;
+ }
+ }
+ if ( $n < 0 ) {
+ $n += pow( 2, 32 );
+ }
+ return $n;
+ }
+
+ /**
+ * Convert a dotted-quad IP to a signed integer
+ * Returns false on failure
+ */
+ public static function toSigned( $ip ) {
+ if ( $ip == '255.255.255.255' ) {
+ $n = -1;
+ } else {
+ $n = ip2long( $ip );
+ if ( $n == -1 ) {
+ $n = false;
+ }
+ }
+ return $n;
+ }
+
+ /**
+ * Convert a network specification in CIDR notation to an integer network and a number of bits
+ */
+ public static function parseCIDR( $range ) {
+ $parts = explode( '/', $range, 2 );
+ if ( count( $parts ) != 2 ) {
+ return array( false, false );
+ }
+ $network = IP::toSigned( $parts[0] );
+ if ( $network !== false && is_numeric( $parts[1] ) && $parts[1] >= 0 && $parts[1] <= 32 ) {
+ $bits = $parts[1];
+ if ( $bits == 0 ) {
+ $network = 0;
+ } else {
+ $network &= ~((1 << (32 - $bits)) - 1);
+ }
+ # Convert to unsigned
+ if ( $network < 0 ) {
+ $network += pow( 2, 32 );
+ }
+ } else {
+ $network = false;
+ $bits = false;
+ }
+ return array( $network, $bits );
+ }
+
+ /**
+ * Given a string range in a number of formats, return the start and end of
+ * the range in hexadecimal.
+ *
+ * Formats are:
+ * 1.2.3.4/24 CIDR
+ * 1.2.3.4 - 1.2.3.5 Explicit range
+ * 1.2.3.4 Single IP
+ */
+ public static function parseRange( $range ) {
+ if ( strpos( $range, '/' ) !== false ) {
+ # CIDR
+ list( $network, $bits ) = IP::parseCIDR( $range );
+ if ( $network === false ) {
+ $start = $end = false;
+ } else {
+ $start = sprintf( '%08X', $network );
+ $end = sprintf( '%08X', $network + pow( 2, (32 - $bits) ) - 1 );
+ }
+ } elseif ( strpos( $range, '-' ) !== false ) {
+ # Explicit range
+ list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
+ if ( $start > $end ) {
+ $start = $end = false;
+ } else {
+ $start = IP::toHex( $start );
+ $end = IP::toHex( $end );
+ }
+ } else {
+ # Single IP
+ $start = $end = IP::toHex( $range );
+ }
+ if ( $start === false || $end === false ) {
+ return array( false, false );
+ } else {
+ return array( $start, $end );
+ }
+ }
+}
+?>