includes/IP.php

   1 <?php
   2 /**
   3  * Functions and constants to play with IP addresses and ranges
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Ashar Voultoiz <hashar at free dot fr>, Aaron Schulz
  22  */
  23
  24 // Some regex definition to "play" with IP address and IP address blocks
  25
  26 // An IP is made of 4 bytes from x00 to xFF which is d0 to d255
  27 define( 'RE_IP_BYTE', '(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|0?[0-9]?[0-9])' );
  28 define( 'RE_IP_ADD' , RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE . '\.' . RE_IP_BYTE );
  29 // An IPv4 block is an IP address and a prefix (d1 to d32)
  30 define( 'RE_IP_PREFIX', '(3[0-2]|[12]?\d)' );
  31 define( 'RE_IP_BLOCK', RE_IP_ADD . '\/' . RE_IP_PREFIX );
  32
  33 // An IPv6 block is an IP address and a prefix (d1 to d128)
  34 define( 'RE_IPV6_WORD', '([0-9A-Fa-f]{1,4})' );
  35 define( 'RE_IPV6_PREFIX', '(12[0-8]|1[01][0-9]|[1-9]?\d)');
  36 // An IPv6 address is made up of 8 words. However, the "::" abbreviation can be used.
  37 define( 'RE_IPV6_ADD',
  38         '(' . // starts with "::" (includes the address "::")
  39                 '(::|:(:' . RE_IPV6_WORD . '){1,7})' .
  40         '|' . // ends with "::" (not including the address "::")
  41                 RE_IPV6_WORD . '(:' . RE_IPV6_WORD . '){0,6}::' .
  42         '|' . // has no "::"
  43                 RE_IPV6_WORD . '(:' . RE_IPV6_WORD . '){7}' .
  44         '|' . // contains one "::" in the middle ("^" check always fails if no "::" found)
  45                 RE_IPV6_WORD . '(:(?P<abbr>(?(abbr)|:))?' . RE_IPV6_WORD . '){1,6}(?(abbr)|^)' .
  46         ')'
  47 );
  48 define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );
  49 // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  50 define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  51 define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  52
  53 // This might be useful for regexps used elsewhere, matches any IPv6 or IPv6 address or network
  54 define( 'IP_ADDRESS_STRING',
  55         '(?:' .
  56                 RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)' . // IPv4
  57         '|' .
  58                 RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)' . // IPv6
  59         ')'
  60 );
  61
  62 /**
  63  * A collection of public static functions to play with IP address
  64  * and IP blocks.
  65  */
  66 class IP {
  67         /**
  68          * Determine if a string is as valid IP address or network (CIDR prefix).
  69          * SIIT IPv4-translated addresses are rejected.
  70          * Note: canonicalize() tries to convert translated addresses to IPv4.
  71          * @param string $ip possible IP address
  72          * @return bool
  73          */
  74         public static function isIPAddress( $ip ) {
  75                 return (bool)preg_match( '/^' . IP_ADDRESS_STRING . '$/', $ip );
  76         }
  77
  78         /**
  79          * Given a string, determine if it as valid IP in IPv6 only.
  80          * Note: Unlike isValid(), this looks for networks too.
  81          * @param string $ip possible IP address
  82          * @return bool
  83          */
  84         public static function isIPv6( $ip ) {
  85                 return (bool)preg_match( '/^' . RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)$/', $ip );
  86         }
  87
  88         /**
  89          * Given a string, determine if it as valid IP in IPv4 only.
  90          * Note: Unlike isValid(), this looks for networks too.
  91          * @param string $ip possible IP address
  92          * @return bool
  93          */
  94         public static function isIPv4( $ip ) {
  95                 return (bool)preg_match( '/^' . RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)$/', $ip );
  96         }
  97
  98         /**
  99          * Validate an IP address. Ranges are NOT considered valid.
 100          * SIIT IPv4-translated addresses are rejected.
 101          * Note: canonicalize() tries to convert translated addresses to IPv4.
 102          * @param string $ip
 103          * @return boolean True if it is valid.
 104          */
 105         public static function isValid( $ip ) {
 106                 return ( preg_match( '/^' . RE_IP_ADD . '$/', $ip )
 107                         || preg_match( '/^' . RE_IPV6_ADD . '$/', $ip ) );
 108         }
 109
 110         /**
 111          * Validate an IP Block (valid address WITH a valid prefix).
 112          * SIIT IPv4-translated addresses are rejected.
 113          * Note: canonicalize() tries to convert translated addresses to IPv4.
 114          * @param string $ipblock
 115          * @return boolean True if it is valid.
 116          */
 117         public static function isValidBlock( $ipblock ) {
 118                 return ( preg_match( '/^' . RE_IPV6_BLOCK . '$/', $ipblock )
 119                         || preg_match( '/^' . RE_IPV4_BLOCK . '$/', $ipblock ) );
 120         }
 121
 122         /**
 123          * Given an IP address in dotted-quad notation, returns an IPv6 octet.
 124          * See http://www.answers.com/topic/ipv4-compatible-address
 125          * IPs with the first 92 bits as zeros are reserved from IPv6
 126          * @param string $ip quad-dotted IP address.
 127          * @return string IPv4 address
 128          */
 129         public static function IPv4toIPv6( $ip ) {
 130                 if ( !self::isIPv4( $ip ) ) {
 131                         throw new MWException( "IPv4toIPv6() called on a non-IPv4 address." );
 132                 }
 133                 // IPv4 address with CIDR
 134                 if ( strpos( $ip, '/' ) !== false ) {
 135                         $parts = explode( '/', $ip, 2 );
 136                         if ( count( $parts ) != 2 ) {
 137                                 return false;
 138                         }
 139                         list( $network, $bits ) = $parts;
 140                         $network = self::toUnsigned( $network );
 141                         if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 142                                 $bits += 96;
 143                                 return self::toOctet( $network ) . "/$bits";
 144                         } else {
 145                                 return false;
 146                         }
 147                 }
 148                 return self::toOctet( self::toUnsigned( $ip ) );
 149         }
 150
 151         /**
 152          * Convert an IP into a nice standard form.
 153          * IPv6 addresses in octet notation are expanded to 8 words.
 154          * IPv4 addresses are just trimmed.
 155          * @param string $ip IP address in quad or octet form (CIDR or not).
 156          * @return string
 157          */
 158         public static function sanitizeIP( $ip ) {
 159                 $ip = trim( $ip );
 160                 if ( $ip === '' ) {
 161                         return null;
 162                 }
 163                 if ( self::isIPv4( $ip ) || !self::isIPv6( $ip ) ) {
 164                         return $ip; // nothing else to do for IPv4 addresses or invalid ones
 165                 }
 166                 // Remove any whitespaces, convert to upper case
 167                 $ip = strtoupper( $ip );
 168                 // Expand zero abbreviations
 169                 $abbrevPos = strpos( $ip, '::' );
 170                 if ( $abbrevPos !== false ) {
 171                         // We know this is valid IPv6. Find the last index of the
 172                         // address before any CIDR number (e.g. "a:b:c::/24").
 173                         $CIDRStart = strpos( $ip, "/" );
 174                         $addressEnd = ( $CIDRStart !== false )
 175                                 ? $CIDRStart - 1
 176                                 : strlen( $ip ) - 1;
 177                         // If the '::' is at the beginning...
 178                         if ( $abbrevPos == 0 ) {
 179                                 $repeat = '0:';
 180                                 $extra = ( $ip == '::' ) ? '0' : ''; // for the address '::'
 181                                 $pad = 9; // 7+2 (due to '::')
 182                         // If the '::' is at the end...
 183                         } elseif ( $abbrevPos == ( $addressEnd - 1 ) ) {
 184                                 $repeat = ':0';
 185                                 $extra = '';
 186                                 $pad = 9; // 7+2 (due to '::')
 187                         // If the '::' is in the middle...
 188                         } else {
 189                                 $repeat = ':0';
 190                                 $extra = ':';
 191                                 $pad = 8; // 6+2 (due to '::')
 192                         }
 193                         $ip = str_replace( '::',
 194                                 str_repeat( $repeat, $pad - substr_count( $ip, ':' ) ) . $extra,
 195                                 $ip
 196                         );
 197                 }
 198                 // Remove leading zereos from each bloc as needed
 199                 $ip = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip );
 200                 return $ip;
 201         }
 202
 203         /**
 204          * Given an unsigned integer, returns an IPv6 address in octet notation
 205          * @param string $ip_int IP address.
 206          * @return string
 207          */
 208         public static function toOctet( $ip_int ) {
 209                 return self::hexToOctet( wfBaseConvert( $ip_int, 10, 16, 32, false ) );
 210         }
 211
 212         /**
 213          * Convert an IPv4 or IPv6 hexadecimal representation back to readable format
 214          * @param string $hex number, with "v6-" prefix if it is IPv6
 215          * @return string quad-dotted (IPv4) or octet notation (IPv6)
 216          */
 217         public static function formatHex( $hex ) {
 218                 if ( substr( $hex, 0, 3 ) == 'v6-' ) { // IPv6
 219                         return self::hexToOctet( substr( $hex, 3 ) );
 220                 } else { // IPv4
 221                         return self::hexToQuad( $hex );
 222                 }
 223         }
 224
 225         /**
 226          * Converts a hexadecimal number to an IPv6 address in octet notation
 227          * @param string $ip_hex pure hex (no v6- prefix)
 228          * @return string (of format a:b:c:d:e:f:g:h)
 229          */
 230         public static function hexToOctet( $ip_hex ) {
 231                 // Pad hex to 32 chars (128 bits)
 232                 $ip_hex = str_pad( strtoupper( $ip_hex ), 32, '0', STR_PAD_LEFT );
 233                 // Separate into 8 words
 234                 $ip_oct = substr( $ip_hex, 0, 4 );
 235                 for ( $n = 1; $n < 8; $n++ ) {
 236                         $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 237                 }
 238                 // NO leading zeroes
 239                 $ip_oct = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip_oct );
 240                 return $ip_oct;
 241         }
 242
 243         /**
 244          * Converts a hexadecimal number to an IPv4 address in quad-dotted notation
 245          * @param string $ip_hex pure hex
 246          * @return string (of format a.b.c.d)
 247          */
 248         public static function hexToQuad( $ip_hex ) {
 249                 // Pad hex to 8 chars (32 bits)
 250                 $ip_hex = str_pad( strtoupper( $ip_hex ), 8, '0', STR_PAD_LEFT );
 251                 // Separate into four quads
 252                 $s = '';
 253                 for ( $i = 0; $i < 4; $i++ ) {
 254                         if ( $s !== '' ) {
 255                                 $s .= '.';
 256                         }
 257                         $s .= base_convert( substr( $ip_hex, $i * 2, 2 ), 16, 10 );
 258                 }
 259                 return $s;
 260         }
 261
 262         /**
 263          * Determine if an IP address really is an IP address, and if it is public,
 264          * i.e. not RFC 1918 or similar
 265          * Comes from ProxyTools.php
 266          * @param string $ip
 267          * @return bool
 268          */
 269         public static function isPublic( $ip ) {
 270                 if ( self::isIPv6( $ip ) ) {
 271                         return self::isPublic6( $ip );
 272                 }
 273                 $n = self::toUnsigned( $ip );
 274                 if ( !$n ) {
 275                         return false;
 276                 }
 277
 278                 // ip2long accepts incomplete addresses, as well as some addresses
 279                 // followed by garbage characters. Check that it's really valid.
 280                 if ( $ip != long2ip( $n ) ) {
 281                         return false;
 282                 }
 283
 284                 static $privateRanges = false;
 285                 if ( !$privateRanges ) {
 286                         $privateRanges = array(
 287                                 array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
 288                                 array( '172.16.0.0',  '172.31.255.255' ),   #     "
 289                                 array( '192.168.0.0', '192.168.255.255' ),  #     "
 290                                 array( '0.0.0.0',     '0.255.255.255' ),    # this network
 291                                 array( '127.0.0.0',   '127.255.255.255' ),  # loopback
 292                         );
 293                 }
 294
 295                 foreach ( $privateRanges as $r ) {
 296                         $start = self::toUnsigned( $r[0] );
 297                         $end = self::toUnsigned( $r[1] );
 298                         if ( $n >= $start && $n <= $end ) {
 299                                 return false;
 300                         }
 301                 }
 302                 return true;
 303         }
 304
 305         /**
 306          * Determine if an IPv6 address really is an IP address, and if it is public,
 307          * i.e. not RFC 4193 or similar
 308          * @param string $ip
 309          * @return bool
 310          */
 311         private static function isPublic6( $ip ) {
 312                 static $privateRanges = false;
 313                 if ( !$privateRanges ) {
 314                         $privateRanges = array(
 315                                 array( 'fc::', 'fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff' ), # RFC 4193 (local)
 316                                 array( '0:0:0:0:0:0:0:1', '0:0:0:0:0:0:0:1' ), # loopback
 317                         );
 318                 }
 319                 $n = self::toHex( $ip );
 320                 foreach ( $privateRanges as $r ) {
 321                         $start = self::toHex( $r[0] );
 322                         $end = self::toHex( $r[1] );
 323                         if ( $n >= $start && $n <= $end ) {
 324                                 return false;
 325                         }
 326                 }
 327                 return true;
 328         }
 329
 330         /**
 331          * Return a zero-padded upper case hexadecimal representation of an IP address.
 332          *
 333          * Hexadecimal addresses are used because they can easily be extended to
 334          * IPv6 support. To separate the ranges, the return value from this
 335          * function for an IPv6 address will be prefixed with "v6-", a non-
 336          * hexadecimal string which sorts after the IPv4 addresses.
 337          *
 338          * @param string $ip Quad dotted/octet IP address.
 339          * @return string
 340          */
 341         public static function toHex( $ip ) {
 342                 if ( self::isIPv6( $ip ) ) {
 343                         $n = 'v6-' . self::IPv6ToRawHex( $ip );
 344                 } else {
 345                         $n = self::toUnsigned( $ip );
 346                         if ( $n !== false ) {
 347                                 $n = wfBaseConvert( $n, 10, 16, 8, false );
 348                         }
 349                 }
 350                 return $n;
 351         }
 352
 353         /**
 354          * Given an IPv6 address in octet notation, returns a pure hex string.
 355          * @param string $ip octet ipv6 IP address.
 356          * @return string pure hex (uppercase)
 357          */
 358         private static function IPv6ToRawHex( $ip ) {
 359                 $ip = self::sanitizeIP( $ip );
 360                 if ( !$ip ) {
 361                         return null;
 362                 }
 363                 $r_ip = '';
 364                 foreach ( explode( ':', $ip ) as $v ) {
 365                         $r_ip .= str_pad( $v, 4, 0, STR_PAD_LEFT );
 366                 }
 367                 return $r_ip;
 368         }
 369
 370         /**
 371          * Given an IP address in dotted-quad/octet notation, returns an unsigned integer.
 372          * Like ip2long() except that it actually works and has a consistent error return value.
 373          * Comes from ProxyTools.php
 374          * @param string $ip Quad dotted IP address.
 375          * @return mixed (string/int/false)
 376          */
 377         public static function toUnsigned( $ip ) {
 378                 if ( self::isIPv6( $ip ) ) {
 379                         $n = self::toUnsigned6( $ip );
 380                 } else {
 381                         $n = ip2long( $ip );
 382                         if ( $n < 0 ) {
 383                                 $n += pow( 2, 32 );
 384                         }
 385                 }
 386                 return $n;
 387         }
 388
 389         private static function toUnsigned6( $ip ) {
 390                 return wfBaseConvert( self::IPv6ToRawHex( $ip ), 16, 10 );
 391         }
 392
 393         /**
 394          * Convert a network specification in CIDR notation
 395          * to an integer network and a number of bits
 396          * @param string $range IP with CIDR prefix
 397          * @return array(int or string, int)
 398          */
 399         public static function parseCIDR( $range ) {
 400                 if ( self::isIPv6( $range ) ) {
 401                         return self::parseCIDR6( $range );
 402                 }
 403                 $parts = explode( '/', $range, 2 );
 404                 if ( count( $parts ) != 2 ) {
 405                         return array( false, false );
 406                 }
 407                 list( $network, $bits ) = $parts;
 408                 $network = ip2long( $network );
 409                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 410                         if ( $bits == 0 ) {
 411                                 $network = 0;
 412                         } else {
 413                                 $network &= ~( ( 1 << ( 32 - $bits ) ) - 1);
 414                         }
 415                         # Convert to unsigned
 416                         if ( $network < 0 ) {
 417                                 $network += pow( 2, 32 );
 418                         }
 419                 } else {
 420                         $network = false;
 421                         $bits = false;
 422                 }
 423                 return array( $network, $bits );
 424         }
 425
 426         /**
 427          * Given a string range in a number of formats,
 428          * return the start and end of the range in hexadecimal.
 429          *
 430          * Formats are:
 431          *     1.2.3.4/24          CIDR
 432          *     1.2.3.4 - 1.2.3.5   Explicit range
 433          *     1.2.3.4             Single IP
 434          *
 435          *     2001:0db8:85a3::7344/96                                   CIDR
 436          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 437          *     2001:0db8:85a3::7344                                      Single IP
 438          * @param string $range IP range
 439          * @return array(string, string)
 440          */
 441         public static function parseRange( $range ) {
 442                 // CIDR notation
 443                 if ( strpos( $range, '/' ) !== false ) {
 444                         if ( self::isIPv6( $range ) ) {
 445                                 return self::parseRange6( $range );
 446                         }
 447                         list( $network, $bits ) = self::parseCIDR( $range );
 448                         if ( $network === false ) {
 449                                 $start = $end = false;
 450                         } else {
 451                                 $start = sprintf( '%08X', $network );
 452                                 $end = sprintf( '%08X', $network + pow( 2, ( 32 - $bits ) ) - 1 );
 453                         }
 454                 // Explicit range
 455                 } elseif ( strpos( $range, '-' ) !== false ) {
 456                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 457                         if ( self::isIPv6( $start ) && self::isIPv6( $end ) ) {
 458                                 return self::parseRange6( $range );
 459                         }
 460                         if ( self::isIPv4( $start ) && self::isIPv4( $end ) ) {
 461                                 $start = self::toUnsigned( $start );
 462                                 $end = self::toUnsigned( $end );
 463                                 if ( $start > $end ) {
 464                                         $start = $end = false;
 465                                 } else {
 466                                         $start = sprintf( '%08X', $start );
 467                                         $end = sprintf( '%08X', $end );
 468                                 }
 469                         } else {
 470                                 $start = $end = false;
 471                         }
 472                 } else {
 473                         # Single IP
 474                         $start = $end = self::toHex( $range );
 475                 }
 476                 if ( $start === false || $end === false ) {
 477                         return array( false, false );
 478                 } else {
 479                         return array( $start, $end );
 480                 }
 481         }
 482
 483         /**
 484          * Convert a network specification in IPv6 CIDR notation to an
 485          * integer network and a number of bits
 486          * @return array(string, int)
 487          */
 488         private static function parseCIDR6( $range ) {
 489                 # Explode into <expanded IP,range>
 490                 $parts = explode( '/', IP::sanitizeIP( $range ), 2 );
 491                 if ( count( $parts ) != 2 ) {
 492                         return array( false, false );
 493                 }
 494                 list( $network, $bits ) = $parts;
 495                 $network = self::IPv6ToRawHex( $network );
 496                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 128 ) {
 497                         if ( $bits == 0 ) {
 498                                 $network = "0";
 499                         } else {
 500                                 # Native 32 bit functions WONT work here!!!
 501                                 # Convert to a padded binary number
 502                                 $network = wfBaseConvert( $network, 16, 2, 128 );
 503                                 # Truncate the last (128-$bits) bits and replace them with zeros
 504                                 $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
 505                                 # Convert back to an integer
 506                                 $network = wfBaseConvert( $network, 2, 10 );
 507                         }
 508                 } else {
 509                         $network = false;
 510                         $bits = false;
 511                 }
 512                 return array( $network, (int)$bits );
 513         }
 514
 515         /**
 516          * Given a string range in a number of formats, return the
 517          * start and end of the range in hexadecimal. For IPv6.
 518          *
 519          * Formats are:
 520          *     2001:0db8:85a3::7344/96                                   CIDR
 521          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 522          *     2001:0db8:85a3::7344/96                                   Single IP
 523          * @return array(string, string)
 524          */
 525         private static function parseRange6( $range ) {
 526                 # Expand any IPv6 IP
 527                 $range = IP::sanitizeIP( $range );
 528                 // CIDR notation...
 529                 if ( strpos( $range, '/' ) !== false ) {
 530                         list( $network, $bits ) = self::parseCIDR6( $range );
 531                         if ( $network === false ) {
 532                                 $start = $end = false;
 533                         } else {
 534                                 $start = wfBaseConvert( $network, 10, 16, 32, false );
 535                                 # Turn network to binary (again)
 536                                 $end = wfBaseConvert( $network, 10, 2, 128 );
 537                                 # Truncate the last (128-$bits) bits and replace them with ones
 538                                 $end = str_pad( substr( $end, 0, $bits ), 128, 1, STR_PAD_RIGHT );
 539                                 # Convert to hex
 540                                 $end = wfBaseConvert( $end, 2, 16, 32, false );
 541                                 # see toHex() comment
 542                                 $start = "v6-$start";
 543                                 $end = "v6-$end";
 544                         }
 545                 // Explicit range notation...
 546                 } elseif ( strpos( $range, '-' ) !== false ) {
 547                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 548                         $start = self::toUnsigned6( $start );
 549                         $end = self::toUnsigned6( $end );
 550                         if ( $start > $end ) {
 551                                 $start = $end = false;
 552                         } else {
 553                                 $start = wfBaseConvert( $start, 10, 16, 32, false );
 554                                 $end = wfBaseConvert( $end, 10, 16, 32, false );
 555                         }
 556                         # see toHex() comment
 557                         $start = "v6-$start";
 558                         $end = "v6-$end";
 559                 } else {
 560                         # Single IP
 561                         $start = $end = self::toHex( $range );
 562                 }
 563                 if ( $start === false || $end === false ) {
 564                         return array( false, false );
 565                 } else {
 566                         return array( $start, $end );
 567                 }
 568         }
 569
 570         /**
 571          * Determine if a given IPv4/IPv6 address is in a given CIDR network
 572          * @param $addr The address to check against the given range.
 573          * @param $range The range to check the given address against.
 574          * @return bool Whether or not the given address is in the given range.
 575          */
 576         public static function isInRange( $addr, $range ) {
 577                 $hexIP = self::toHex( $addr );
 578                 list( $start, $end ) = self::parseRange( $range );
 579                 return ( strcmp( $hexIP, $start ) >= 0 &&
 580                         strcmp( $hexIP, $end ) <= 0 );
 581         }
 582
 583         /**
 584          * Convert some unusual representations of IPv4 addresses to their
 585          * canonical dotted quad representation.
 586          *
 587          * This currently only checks a few IPV4-to-IPv6 related cases.  More
 588          * unusual representations may be added later.
 589          *
 590          * @param $addr something that might be an IP address
 591          * @return valid dotted quad IPv4 address or null
 592          */
 593         public static function canonicalize( $addr ) {
 594                 if ( self::isValid( $addr ) ) {
 595                         return $addr;
 596                 }
 597                 // Turn mapped addresses from ::ce:ffff:1.2.3.4 to 1.2.3.4
 598                 if ( strpos( $addr, ':' ) !== false && strpos( $addr, '.' ) !== false ) {
 599                         $addr = substr( $addr, strrpos( $addr, ':' ) + 1 );
 600                         if ( self::isIPv4( $addr ) ) {
 601                                 return $addr;
 602                         }
 603                 }
 604                 // IPv6 loopback address
 605                 $m = array();
 606                 if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) ) {
 607                         return '127.0.0.1';
 608                 }
 609                 // IPv4-mapped and IPv4-compatible IPv6 addresses
 610                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) ) {
 611                         return $m[1];
 612                 }
 613                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD .
 614                         ':' . RE_IPV6_WORD . '$/i', $addr, $m ) )
 615                 {
 616                         return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 617                 }
 618
 619                 return null;  // give up
 620         }
 621 }