includes/IP.php

   1 <?php
   2 /*
   3  * Collection of public static functions to play with IP address
   4  * and IP blocks.
   5  *
   6  * @Author "Ashar Voultoiz" <hashar@altern.org>
   7  * @License GPL v2 or later
   8  */
   9
  10 // Some regex definition to "play" with IP address and IP address blocks
  11
  12 // An IP is made of 4 bytes from x00 to xFF which is d0 to d255
  13 define( 'RE_IP_BYTE', '(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)');
  14 define( 'RE_IP_ADD' , RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE );
  15 // An IP block is an IP address and a prefix (d1 to d32)
  16 define( 'RE_IP_PREFIX', '(3[0-2]|[12]?\d)');
  17 define( 'RE_IP_BLOCK', RE_IP_ADD . '\/' . RE_IP_PREFIX);
  18 // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  19 define( 'RE_IPV6_WORD', '([0-9A-Fa-f]{1,4})' );
  20 define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  21 define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  22
  23 class IP {
  24
  25         /**
  26          * Validate an IP address.
  27          * @return boolean True if it is valid.
  28          */
  29         public static function isValid( $ip ) {
  30                 return preg_match( '/^' . RE_IP_ADD . '$/', $ip) ;
  31         }
  32
  33         /**
  34          * Validate an IP Block.
  35          * @return boolean True if it is valid.
  36          */
  37         public static function isValidBlock( $ipblock ) {
  38                 return ( count(self::toArray($ipblock)) == 1 + 5 );
  39         }
  40
  41         /**
  42          * Determine if an IP address really is an IP address, and if it is public,
  43          * i.e. not RFC 1918 or similar
  44          * Comes from ProxyTools.php
  45          */
  46         public static function isPublic( $ip ) {
  47                 $n = IP::toUnsigned( $ip );
  48                 if ( !$n ) {
  49                         return false;
  50                 }
  51
  52                 // ip2long accepts incomplete addresses, as well as some addresses
  53                 // followed by garbage characters. Check that it's really valid.
  54                 if( $ip != long2ip( $n ) ) {
  55                         return false;
  56                 }
  57
  58                 static $privateRanges = false;
  59                 if ( !$privateRanges ) {
  60                         $privateRanges = array(
  61                                 array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
  62                                 array( '172.16.0.0',  '172.31.255.255' ),   #     "
  63                                 array( '192.168.0.0', '192.168.255.255' ),  #     "
  64                                 array( '0.0.0.0',     '0.255.255.255' ),    # this network
  65                                 array( '127.0.0.0',   '127.255.255.255' ),  # loopback
  66                         );
  67                 }
  68
  69                 foreach ( $privateRanges as $r ) {
  70                         $start = IP::toUnsigned( $r[0] );
  71                         $end = IP::toUnsigned( $r[1] );
  72                         if ( $n >= $start && $n <= $end ) {
  73                                 return false;
  74                         }
  75                 }
  76                 return true;
  77         }
  78
  79         /**
  80          * Split out an IP block as an array of 4 bytes and a mask,
  81          * return false if it cant be determined
  82          *
  83          * @parameter $ip string A quad dotted IP address
  84          * @return array
  85          */
  86         public static function toArray( $ipblock ) {
  87                 $matches = array();
  88                 if(! preg_match( '/^' . RE_IP_ADD . '(?:\/(?:'.RE_IP_PREFIX.'))?' . '$/', $ipblock, $matches ) ) {
  89                         return false;
  90                 } else {
  91                         return $matches;
  92                 }
  93         }
  94
  95         /**
  96          * Return a zero-padded hexadecimal representation of an IP address.
  97          *
  98          * Hexadecimal addresses are used because they can easily be extended to
  99          * IPv6 support. To separate the ranges, the return value from this
 100          * function for an IPv6 address will be prefixed with "v6-", a non-
 101          * hexadecimal string which sorts after the IPv4 addresses.
 102          *
 103          * @param $ip Quad dotted IP address.
 104          */
 105         public static function toHex( $ip ) {
 106                 $n = self::toUnsigned( $ip );
 107                 if ( $n !== false ) {
 108                         $n = sprintf( '%08X', $n );
 109                 }
 110                 return $n;
 111         }
 112
 113         /**
 114          * Given an IP address in dotted-quad notation, returns an unsigned integer.
 115          * Like ip2long() except that it actually works and has a consistent error return value.
 116          * Comes from ProxyTools.php
 117          * @param $ip Quad dotted IP address.
 118          */
 119         public static function toUnsigned( $ip ) {
 120                 if ( $ip == '255.255.255.255' ) {
 121                         $n = -1;
 122                 } else {
 123                         $n = ip2long( $ip );
 124                         if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
 125                                 $n = false;
 126                         }
 127                 }
 128                 if ( $n < 0 ) {
 129                         $n += pow( 2, 32 );
 130                 }
 131                 return $n;
 132         }
 133
 134         /**
 135          * Convert a dotted-quad IP to a signed integer
 136          * Returns false on failure
 137          */
 138         public static function toSigned( $ip ) {
 139                 if ( $ip == '255.255.255.255' ) {
 140                         $n = -1;
 141                 } else {
 142                         $n = ip2long( $ip );
 143                         if ( $n == -1 ) {
 144                                 $n = false;
 145                         }
 146                 }
 147                 return $n;
 148         }
 149
 150         /**
 151          * Convert a network specification in CIDR notation to an integer network and a number of bits
 152          */
 153         public static function parseCIDR( $range ) {
 154                 $parts = explode( '/', $range, 2 );
 155                 if ( count( $parts ) != 2 ) {
 156                         return array( false, false );
 157                 }
 158                 $network = IP::toSigned( $parts[0] );
 159                 if ( $network !== false && is_numeric( $parts[1] ) && $parts[1] >= 0 && $parts[1] <= 32 ) {
 160                         $bits = $parts[1];
 161                         if ( $bits == 0 ) {
 162                                 $network = 0;
 163                         } else {
 164                                 $network &= ~((1 << (32 - $bits)) - 1);
 165                         }
 166                         # Convert to unsigned
 167                         if ( $network < 0 ) {
 168                                 $network += pow( 2, 32 );
 169                         }
 170                 } else {
 171                         $network = false;
 172                         $bits = false;
 173                 }
 174                 return array( $network, $bits );
 175         }
 176
 177         /**
 178          * Given a string range in a number of formats, return the start and end of
 179          * the range in hexadecimal.
 180          *
 181          * Formats are:
 182          *     1.2.3.4/24          CIDR
 183          *     1.2.3.4 - 1.2.3.5   Explicit range
 184          *     1.2.3.4             Single IP
 185          */
 186         public static function parseRange( $range ) {
 187                 if ( strpos( $range, '/' ) !== false ) {
 188                         # CIDR
 189                         list( $network, $bits ) = IP::parseCIDR( $range );
 190                         if ( $network === false ) {
 191                                 $start = $end = false;
 192                         } else {
 193                                 $start = sprintf( '%08X', $network );
 194                                 $end = sprintf( '%08X', $network + pow( 2, (32 - $bits) ) - 1 );
 195                         }
 196                 } elseif ( strpos( $range, '-' ) !== false ) {
 197                         # Explicit range
 198                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 199                         if ( $start > $end ) {
 200                                 $start = $end = false;
 201                         } else {
 202                                 $start = IP::toHex( $start );
 203                                 $end = IP::toHex( $end );
 204                         }
 205                 } else {
 206                         # Single IP
 207                         $start = $end = IP::toHex( $range );
 208                 }
 209                 if ( $start === false || $end === false ) {
 210                         return array( false, false );
 211                 } else {
 212                         return array( $start, $end );
 213                 }
 214     }
 215
 216     /**
 217      * Determine if a given integer IPv4 address is in a given CIDR network
 218      * @param $addr The address to check against the given range.
 219      * @param $range The range to check the given address against.
 220      * @return bool Whether or not the given address is in the given range.
 221      */
 222     public static function isInRange( $addr, $range ) {
 223         $unsignedIP = IP::toUnsigned($addr);
 224         list( $start, $end ) = IP::parseRange($range);
 225
 226         return (($unsignedIP >= $start) && ($unsignedIP <= $end));
 227     }
 228
 229     /**
 230      * Convert some unusual representations of IPv4 addresses to their
 231      * canonical dotted quad representation.
 232      *
 233      * This currently only checks a few IPV4-to-IPv6 related cases.  More
 234      * unusual representations may be added later.
 235      *
 236      * @param $addr something that might be an IP address
 237      * @return valid dotted quad IPv4 address or null
 238      */
 239     public static function canonicalize( $addr ) {
 240         if ( IP::isValid( $addr ) )
 241             return $addr;
 242
 243         // IPv6 loopback address
 244         if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) )
 245             return '127.0.0.1';
 246
 247         // IPv4-mapped and IPv4-compatible IPv6 addresses
 248         if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) )
 249             return $m[1];
 250         if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD . ':' . RE_IPV6_WORD . '$/i', $addr, $m ) )
 251             return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 252
 253         return null;  // give up
 254     }
 255 }
 256
 257 ?>