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, $matches) ;
  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( $ipblock ) {
  87                 if(! preg_match( '/^' . RE_IP_ADD . '(?:\/(?:'.RE_IP_PREFIX.'))?' . '$/', $ipblock, $matches ) ) {
  88                         return false;
  89                 } else {
  90                         return $matches;
  91                 }
  92         }
  93
  94         /**
  95          * Return a zero-padded hexadecimal representation of an IP address.
  96          *
  97          * Hexadecimal addresses are used because they can easily be extended to
  98          * IPv6 support. To separate the ranges, the return value from this
  99          * function for an IPv6 address will be prefixed with "v6-", a non-
 100          * hexadecimal string which sorts after the IPv4 addresses.
 101          *
 102          * @param $ip Quad dotted IP address.
 103          */
 104         public static function toHex( $ip ) {
 105                 $n = self::toUnsigned( $ip );
 106                 if ( $n !== false ) {
 107                         $n = sprintf( '%08X', $n );
 108                 }
 109                 return $n;
 110         }
 111
 112         /**
 113          * Given an IP address in dotted-quad notation, returns an unsigned integer.
 114          * Like ip2long() except that it actually works and has a consistent error return value.
 115          * Comes from ProxyTools.php
 116          * @param $ip Quad dotted IP address.
 117          */
 118         public static function toUnsigned( $ip ) {
 119                 if ( $ip == '255.255.255.255' ) {
 120                         $n = -1;
 121                 } else {
 122                         $n = ip2long( $ip );
 123                         if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
 124                                 $n = false;
 125                         }
 126                 }
 127                 if ( $n < 0 ) {
 128                         $n += pow( 2, 32 );
 129                 }
 130                 return $n;
 131         }
 132
 133         /**
 134          * Convert a dotted-quad IP to a signed integer
 135          * Returns false on failure
 136          */
 137         public static function toSigned( $ip ) {
 138                 if ( $ip == '255.255.255.255' ) {
 139                         $n = -1;
 140                 } else {
 141                         $n = ip2long( $ip );
 142                         if ( $n == -1 ) {
 143                                 $n = false;
 144                         }
 145                 }
 146                 return $n;
 147         }
 148
 149         /**
 150          * Convert a network specification in CIDR notation to an integer network and a number of bits
 151          */
 152         public static function parseCIDR( $range ) {
 153                 $parts = explode( '/', $range, 2 );
 154                 if ( count( $parts ) != 2 ) {
 155                         return array( false, false );
 156                 }
 157                 $network = IP::toSigned( $parts[0] );
 158                 if ( $network !== false && is_numeric( $parts[1] ) && $parts[1] >= 0 && $parts[1] <= 32 ) {
 159                         $bits = $parts[1];
 160                         if ( $bits == 0 ) {
 161                                 $network = 0;
 162                         } else {
 163                                 $network &= ~((1 << (32 - $bits)) - 1);
 164                         }
 165                         # Convert to unsigned
 166                         if ( $network < 0 ) {
 167                                 $network += pow( 2, 32 );
 168                         }
 169                 } else {
 170                         $network = false;
 171                         $bits = false;
 172                 }
 173                 return array( $network, $bits );
 174         }
 175
 176         /**
 177          * Given a string range in a number of formats, return the start and end of
 178          * the range in hexadecimal.
 179          *
 180          * Formats are:
 181          *     1.2.3.4/24          CIDR
 182          *     1.2.3.4 - 1.2.3.5   Explicit range
 183          *     1.2.3.4             Single IP
 184          */
 185         public static function parseRange( $range ) {
 186                 if ( strpos( $range, '/' ) !== false ) {
 187                         # CIDR
 188                         list( $network, $bits ) = IP::parseCIDR( $range );
 189                         if ( $network === false ) {
 190                                 $start = $end = false;
 191                         } else {
 192                                 $start = sprintf( '%08X', $network );
 193                                 $end = sprintf( '%08X', $network + pow( 2, (32 - $bits) ) - 1 );
 194                         }
 195                 } elseif ( strpos( $range, '-' ) !== false ) {
 196                         # Explicit range
 197                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 198                         if ( $start > $end ) {
 199                                 $start = $end = false;
 200                         } else {
 201                                 $start = IP::toHex( $start );
 202                                 $end = IP::toHex( $end );
 203                         }
 204                 } else {
 205                         # Single IP
 206                         $start = $end = IP::toHex( $range );
 207                 }
 208                 if ( $start === false || $end === false ) {
 209                         return array( false, false );
 210                 } else {
 211                         return array( $start, $end );
 212                 }
 213     }
 214
 215     /**
 216      * Determine if a given integer IPv4 address is in a given CIDR network
 217      * @param $addr The address to check against the given range.
 218      * @param $range The range to check the given address against.
 219      * @return bool Whether or not the given address is in the given range.
 220      */
 221     public static function isInRange( $addr, $range ) {
 222         $unsignedIP = IP::toUnsigned($addr);
 223         list( $start, $end ) = IP::parseRange($range);
 224
 225         return (($unsignedIP >= $start) && ($unsignedIP <= $end));
 226     }
 227
 228     /**
 229      * Convert some unusual representations of IPv4 addresses to their
 230      * canonical dotted quad representation.
 231      *
 232      * This currently only checks a few IPV4-to-IPv6 related cases.  More
 233      * unusual representations may be added later.
 234      *
 235      * @param $addr something that might be an IP address
 236      * @return valid dotted quad IPv4 address or null
 237      */
 238     public static function canonicalize( $addr ) {
 239         if ( IP::isValid( $addr ) )
 240             return $addr;
 241
 242         // IPv6 loopback address
 243         if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) )
 244             return '127.0.0.1';
 245
 246         // IPv4-mapped and IPv4-compatible IPv6 addresses
 247         if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) )
 248             return $m[1];
 249         if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD . ':' . RE_IPV6_WORD . '$/i', $addr, $m ) )
 250             return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 251
 252         return null;  // give up
 253     }
 254 }
 255
 256 ?>