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 // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  33 define( 'RE_IPV6_WORD', '([0-9A-Fa-f]{1,4})' );
  34 define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  35 define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  36 // An IPv6 block is an IP address and a prefix (d1 to d128)
  37 define( 'RE_IPV6_PREFIX', '(12[0-8]|1[01][0-9]|[1-9]?\d)');
  38 // An IPv6 address is made up of 8 octets. However, the "::" abbreviations can be used.
  39 define( 'RE_IPV6_ADD',
  40         '(' . // starts with "::" (includes the address "::")
  41                 '(::|:(:' . RE_IPV6_WORD . '){1,7})' .
  42         '|' . // ends with "::" (not including the address "::")
  43                 RE_IPV6_WORD . '(:' . RE_IPV6_WORD . '){0,6}::' .
  44         '|' . // has no "::"
  45                 RE_IPV6_WORD . '(:' . RE_IPV6_WORD . '){7}' .
  46         '|' . // contains one "::" in the middle ("^" check always fails if no "::" found)
  47                 RE_IPV6_WORD . '(:(?P<abbr>(?(abbr)|:))?' . RE_IPV6_WORD . '){1,6}(?(abbr)|^)' .
  48         ')'
  49 );
  50 define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );
  51 // This might be useful for regexps used elsewhere, matches any IPv6 or IPv6 address or network
  52 define( 'IP_ADDRESS_STRING',
  53         '(?:' .
  54                 RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)' . // IPv4
  55         '|' .
  56                 RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)' . // IPv6
  57         ')'
  58 );
  59
  60 /**
  61  * A collection of public static functions to play with IP address
  62  * and IP blocks.
  63  */
  64 class IP {
  65         /**
  66          * Given a string, determine if it as valid IP.
  67          * Note: Unlike isValid(), this looks for networks too.
  68          * @param string $ip possible IP address
  69          * @return bool
  70          */
  71         public static function isIPAddress( $ip ) {
  72                 return (bool)preg_match( '/^' . IP_ADDRESS_STRING . '$/', $ip );
  73         }
  74
  75         /**
  76          * Given a string, determine if it as valid IP in IPv6 only.
  77          * Note: Unlike isValid(), this looks for networks too.
  78          * @param string $ip possible IP address
  79          * @return bool
  80          */
  81         public static function isIPv6( $ip ) {
  82                 return (bool)preg_match( '/^' . RE_IPV6_ADD . '(\/' . RE_IPV6_PREFIX . '|)$/', $ip );
  83         }
  84
  85         /**
  86          * Given a string, determine if it as valid IP in IPv4 only.
  87          * Note: Unlike isValid(), this looks for networks too.
  88          * @param string $ip possible IP address
  89          * @return bool
  90          */
  91         public static function isIPv4( $ip ) {
  92                 return (bool)preg_match( '/^' . RE_IP_ADD . '(\/' . RE_IP_PREFIX . '|)$/', $ip );
  93         }
  94
  95         /**
  96          * Given an IP address in dotted-quad notation, returns an IPv6 octet.
  97          * See http://www.answers.com/topic/ipv4-compatible-address
  98          * IPs with the first 92 bits as zeros are reserved from IPv6
  99          * @param string $ip quad-dotted IP address.
 100          * @return string
 101          */
 102         public static function IPv4toIPv6( $ip ) {
 103                 if ( !$ip ) {
 104                         return null;
 105                 }
 106                 // Convert only if needed
 107                 if ( self::isIPv6( $ip ) ) {
 108                         return $ip;
 109                 }
 110                 // IPv4 address with CIDR
 111                 if ( strpos( $ip, '/' ) !== false ) {
 112                         $parts = explode( '/', $ip, 2 );
 113                         if ( count( $parts ) != 2 ) {
 114                                 return false;
 115                         }
 116                         list( $network, $bits ) = $parts;
 117                         $network = self::toUnsigned( $network );
 118                         if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 119                                 $bits += 96;
 120                                 return self::toOctet( $network ) . "/$bits";
 121                         } else {
 122                                 return false;
 123                         }
 124                 }
 125                 return self::toOctet( self::toUnsigned( $ip ) );
 126         }
 127
 128         private static function toUnsigned6( $ip ) {
 129                 if ( self::isIPv6( $ip ) ) {
 130                         return wfBaseConvert( self::IPv6ToRawHex( $ip ), 16, 10 );
 131                 }
 132                 return false;
 133         }
 134
 135         /**
 136          * Convert an IP into a nice standard form.
 137          * IPv6 addresses in octet notation are expanded to 8 octets.
 138          * IPv4 addresses are just trimmed.
 139          * @param string $ip IP address in quad or octet form (CIDR or not).
 140          * @return string
 141          */
 142         public static function sanitizeIP( $ip ) {
 143                 $ip = trim( $ip );
 144                 if ( $ip === '' ) {
 145                         return null;
 146                 }
 147                 if ( self::isIPv4( $ip ) || !self::isIPv6( $ip ) ) {
 148                         return $ip; // nothing else to do for IPv4 addresses or invalid ones
 149                 }
 150                 // Remove any whitespaces, convert to upper case
 151                 $ip = strtoupper( $ip );
 152                 // Expand zero abbreviations
 153                 $abbrevPos = strpos( $ip, '::' );
 154                 if ( $abbrevPos !== false ) {
 155                         // We know this is valid IPv6. Find the last index of the
 156                         // address before any CIDR number (e.g. "a:b:c::/24").
 157                         $CIDRStart = strpos( $ip, "/" );
 158                         $addressEnd = ( $CIDRStart !== false )
 159                                 ? $CIDRStart - 1
 160                                 : strlen( $ip ) - 1;
 161                         // If the '::' is at the beginning...
 162                         if( $abbrevPos == 0 ) {
 163                                 $repeat = '0:';
 164                                 $extra = ( $ip == '::' ) ? '0' : ''; // for the address '::'
 165                                 $pad = 9; // 7+2 (due to '::')
 166                         // If the '::' is at the end...
 167                         } elseif( $abbrevPos == ( $addressEnd - 1 ) ) {
 168                                 $repeat = ':0';
 169                                 $extra = '';
 170                                 $pad = 9; // 7+2 (due to '::')
 171                         // If the '::' is in the middle...
 172                         } else {
 173                                 $repeat = ':0';
 174                                 $extra = ':';
 175                                 $pad = 8; // 6+2 (due to '::')
 176                         }
 177                         $ip = str_replace( '::',
 178                                 str_repeat( $repeat, $pad - substr_count( $ip, ':' ) ) . $extra,
 179                                 $ip
 180                         );
 181                 }
 182                 // Remove leading zereos from each bloc as needed
 183                 $ip = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip );
 184                 return $ip;
 185         }
 186
 187         /**
 188          * Given an unsigned integer, returns an IPv6 address in octet notation
 189          * @param string $ip_int IP address.
 190          * @return string
 191          */
 192         public static function toOctet( $ip_int ) {
 193                 $ip_hex = wfBaseConvert( $ip_int, 10, 16, 32, false ); // uppercase hex
 194                 return self::hexToOctet( $ip_hex );
 195         }
 196
 197         /**
 198          * Convert an IPv4 or IPv6 hexadecimal representation back to readable format
 199          * @param string $hex number, with "v6-" prefix if it is IPv6
 200          * @return string quad-dotted (IPv4) or octet notation (IPv6)
 201          */
 202         public static function formatHex( $hex ) {
 203                 if ( substr( $hex, 0, 3 ) == 'v6-' ) { // IPv6
 204                         return self::hexToOctet( substr( $hex, 3 ) );
 205                 } else { // IPv4
 206                         return self::hexToQuad( $hex );
 207                 }
 208         }
 209
 210         /**
 211          * Converts a hexadecimal number to an IPv6 address in octet notation
 212          * @param string $ip_hex pure hex (no v6- prefix)
 213          * @return string (of format a:b:c:d:e:f:g:h)
 214          */
 215         public static function hexToOctet( $ip_hex ) {
 216                 // Convert to padded uppercase hex
 217                 $ip_hex = str_pad( strtoupper( $ip_hex ), 32, '0', STR_PAD_LEFT );
 218                 // Separate into 8 octets
 219                 $ip_oct = substr( $ip_hex, 0, 4 );
 220                 for ( $n = 1; $n < 8; $n++ ) {
 221                         $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 222                 }
 223                 // NO leading zeroes
 224                 $ip_oct = preg_replace( '/(^|:)0+' . RE_IPV6_WORD . '/', '$1$2', $ip_oct );
 225                 return $ip_oct;
 226         }
 227
 228         /**
 229          * Converts a hexadecimal number to an IPv4 address in quad-dotted notation
 230          * @param string $ip_hex pure hex
 231          * @return string (of format a.b.c.d)
 232          */
 233         public static function hexToQuad( $ip_hex ) {
 234                 // Convert to padded uppercase hex
 235                 $ip_hex = str_pad( strtoupper( $ip_hex ), 8, '0', STR_PAD_LEFT );
 236                 // Separate into four quads
 237                 $s = '';
 238                 for ( $i = 0; $i < 4; $i++ ) {
 239                         if ( $s !== '' ) {
 240                                 $s .= '.';
 241                         }
 242                         $s .= base_convert( substr( $ip_hex, $i * 2, 2 ), 16, 10 );
 243                 }
 244                 return $s;
 245         }
 246
 247         /**
 248          * Convert a network specification in IPv6 CIDR notation to an
 249          * integer network and a number of bits
 250          * @return array(string, int)
 251          */
 252         private static function parseCIDR6( $range ) {
 253                 # Explode into <expanded IP,range>
 254                 $parts = explode( '/', IP::sanitizeIP( $range ), 2 );
 255                 if ( count( $parts ) != 2 ) {
 256                         return array( false, false );
 257                 }
 258                 list( $network, $bits ) = $parts;
 259                 $network = self::IPv6ToRawHex( $network );
 260                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 128 ) {
 261                         if ( $bits == 0 ) {
 262                                 $network = "0";
 263                         } else {
 264                                 # Native 32 bit functions WONT work here!!!
 265                                 # Convert to a padded binary number
 266                                 $network = wfBaseConvert( $network, 16, 2, 128 );
 267                                 # Truncate the last (128-$bits) bits and replace them with zeros
 268                                 $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
 269                                 # Convert back to an integer
 270                                 $network = wfBaseConvert( $network, 2, 10 );
 271                         }
 272                 } else {
 273                         $network = false;
 274                         $bits = false;
 275                 }
 276                 return array( $network, (int)$bits );
 277         }
 278
 279         /**
 280          * Given a string range in a number of formats, return the
 281          * start and end of the range in hexadecimal. For IPv6.
 282          *
 283          * Formats are:
 284          *     2001:0db8:85a3::7344/96                                   CIDR
 285          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 286          *     2001:0db8:85a3::7344/96                                   Single IP
 287          * @return array(string, int)
 288          */
 289         private static function parseRange6( $range ) {
 290                 # Expand any IPv6 IP
 291                 $range = IP::sanitizeIP( $range );
 292                 // CIDR notation...
 293                 if ( strpos( $range, '/' ) !== false ) {
 294                         list( $network, $bits ) = self::parseCIDR6( $range );
 295                         if ( $network === false ) {
 296                                 $start = $end = false;
 297                         } else {
 298                                 $start = wfBaseConvert( $network, 10, 16, 32, false );
 299                                 # Turn network to binary (again)
 300                                 $end = wfBaseConvert( $network, 10, 2, 128 );
 301                                 # Truncate the last (128-$bits) bits and replace them with ones
 302                                 $end = str_pad( substr( $end, 0, $bits ), 128, 1, STR_PAD_RIGHT );
 303                                 # Convert to hex
 304                                 $end = wfBaseConvert( $end, 2, 16, 32, false );
 305                                 # see toHex() comment
 306                                 $start = "v6-$start";
 307                                 $end = "v6-$end";
 308                         }
 309                 // Explicit range notation...
 310                 } elseif ( strpos( $range, '-' ) !== false ) {
 311                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 312                         $start = self::toUnsigned6( $start );
 313                         $end = self::toUnsigned6( $end );
 314                         if ( $start > $end ) {
 315                                 $start = $end = false;
 316                         } else {
 317                                 $start = wfBaseConvert( $start, 10, 16, 32, false );
 318                                 $end = wfBaseConvert( $end, 10, 16, 32, false );
 319                         }
 320                         # see toHex() comment
 321                         $start = "v6-$start";
 322                         $end = "v6-$end";
 323                 } else {
 324                         # Single IP
 325                         $start = $end = self::toHex( $range );
 326                 }
 327                 if ( $start === false || $end === false ) {
 328                         return array( false, false );
 329                 } else {
 330                         return array( $start, $end );
 331                 }
 332         }
 333
 334         /**
 335          * Validate an IP address. Ranges are NOT considered valid.
 336          * @param string $ip
 337          * @return boolean True if it is valid.
 338          */
 339         public static function isValid( $ip ) {
 340                 return ( preg_match( '/^' . RE_IP_ADD . '$/', $ip )
 341                         || preg_match( '/^' . RE_IPV6_ADD . '$/', $ip ) );
 342         }
 343
 344         /**
 345          * Validate an IP Block (valid address WITH a valid prefix).
 346          * @param string $ipblock
 347          * @return boolean True if it is valid.
 348          */
 349         public static function isValidBlock( $ipblock ) {
 350                 return ( preg_match( '/^' . RE_IPV6_BLOCK . '$/', $ipblock )
 351                         || preg_match( '/^' . RE_IPV4_BLOCK . '$/', $ipblock ) );
 352         }
 353
 354         /**
 355          * Determine if an IP address really is an IP address, and if it is public,
 356          * i.e. not RFC 1918 or similar
 357          * Comes from ProxyTools.php
 358          * @param string $ip
 359          * @return bool
 360          */
 361         public static function isPublic( $ip ) {
 362                 if ( self::isIPv6( $ip ) ) {
 363                         return self::isPublic6( $ip );
 364                 }
 365                 $n = self::toUnsigned( $ip );
 366                 if ( !$n ) {
 367                         return false;
 368                 }
 369
 370                 // ip2long accepts incomplete addresses, as well as some addresses
 371                 // followed by garbage characters. Check that it's really valid.
 372                 if( $ip != long2ip( $n ) ) {
 373                         return false;
 374                 }
 375
 376                 static $privateRanges = false;
 377                 if ( !$privateRanges ) {
 378                         $privateRanges = array(
 379                                 array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
 380                                 array( '172.16.0.0',  '172.31.255.255' ),   #     "
 381                                 array( '192.168.0.0', '192.168.255.255' ),  #     "
 382                                 array( '0.0.0.0',     '0.255.255.255' ),    # this network
 383                                 array( '127.0.0.0',   '127.255.255.255' ),  # loopback
 384                         );
 385                 }
 386
 387                 foreach ( $privateRanges as $r ) {
 388                         $start = self::toUnsigned( $r[0] );
 389                         $end = self::toUnsigned( $r[1] );
 390                         if ( $n >= $start && $n <= $end ) {
 391                                 return false;
 392                         }
 393                 }
 394                 return true;
 395         }
 396
 397         /**
 398          * Determine if an IPv6 address really is an IP address, and if it is public,
 399          * i.e. not RFC 4193 or similar
 400          * @param string $ip
 401          * @return bool
 402          */
 403         private static function isPublic6( $ip ) {
 404                 static $privateRanges = false;
 405                 if ( !$privateRanges ) {
 406                         $privateRanges = array(
 407                                 array( 'fc::', 'fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff' ), # RFC 4193 (local)
 408                                 array( '0:0:0:0:0:0:0:1', '0:0:0:0:0:0:0:1' ),  # loopback
 409                         );
 410                 }
 411                 $n = self::toHex( $ip );
 412                 foreach ( $privateRanges as $r ) {
 413                         $start = self::toHex( $r[0] );
 414                         $end = self::toHex( $r[1] );
 415                         if ( $n >= $start && $n <= $end ) {
 416                                 return false;
 417                         }
 418                 }
 419                 return true;
 420         }
 421
 422         /**
 423          * Return a zero-padded upper case hexadecimal representation of an IP address.
 424          *
 425          * Hexadecimal addresses are used because they can easily be extended to
 426          * IPv6 support. To separate the ranges, the return value from this
 427          * function for an IPv6 address will be prefixed with "v6-", a non-
 428          * hexadecimal string which sorts after the IPv4 addresses.
 429          *
 430          * @param string $ip Quad dotted/octet IP address.
 431          * @return string
 432          */
 433         public static function toHex( $ip ) {
 434                 if ( self::isIPv6( $ip ) ) {
 435                         $n = 'v6-' . self::IPv6ToRawHex( $ip );
 436                 } else {
 437                         $n = self::toUnsigned( $ip );
 438                         if ( $n !== false ) {
 439                                 $n = wfBaseConvert( $n, 10, 16, 8, false );
 440                         }
 441                 }
 442                 return $n;
 443         }
 444
 445         /**
 446          * Given an IP address in dotted-quad/octet notation, returns an unsigned integer.
 447          * Like ip2long() except that it actually works and has a consistent error return value.
 448          * Comes from ProxyTools.php
 449          * @param string $ip Quad dotted IP address.
 450          * @return mixed (string/int/false)
 451          */
 452         public static function toUnsigned( $ip ) {
 453                 if ( self::isIPv6( $ip ) ) {
 454                         $n = wfBaseConvert( self::IPv6ToRawHex( $ip ), 16, 10 );
 455                 } else {
 456                         if ( $ip == '255.255.255.255' ) {
 457                                 $n = -1;
 458                         } else {
 459                                 $n = ip2long( $ip );
 460                                 if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
 461                                         $n = false;
 462                                 }
 463                         }
 464                         if ( $n < 0 ) {
 465                                 $n += pow( 2, 32 );
 466                         }
 467                 }
 468                 return $n;
 469         }
 470
 471         /**
 472          * Given an IPv6 address in octet notation, returns a pure hex string.
 473          * @param string $ip octet ipv6 IP address.
 474          * @return string hex (uppercase)
 475          */
 476         private static function IPv6ToRawHex( $ip ) {
 477                 $ip = self::sanitizeIP( $ip );
 478                 if ( !$ip ) {
 479                         return null;
 480                 }
 481                 $r_ip = '';
 482                 foreach ( explode( ':', $ip ) as $v ) {
 483                         $r_ip .= str_pad( $v, 4, 0, STR_PAD_LEFT );
 484                 }
 485                 return $r_ip;
 486         }
 487
 488         /**
 489          * Convert a dotted-quad IP to a signed integer
 490          * @param string $ip
 491          * @return mixed (string/false)
 492          */
 493         public static function toSigned( $ip ) {
 494                 if ( $ip == '255.255.255.255' ) {
 495                         $n = -1;
 496                 } else {
 497                         $n = ip2long( $ip );
 498                         if ( $n == -1 ) {
 499                                 $n = false;
 500                         }
 501                 }
 502                 return $n;
 503         }
 504
 505         /**
 506          * Convert a network specification in CIDR notation to an integer network and a number of bits
 507          * @param string $range (CIDR IP)
 508          * @return array(int, int)
 509          */
 510         public static function parseCIDR( $range ) {
 511                 $parts = explode( '/', $range, 2 );
 512                 if ( count( $parts ) != 2 ) {
 513                         return array( false, false );
 514                 }
 515                 list( $network, $bits ) = $parts;
 516                 $network = self::toSigned( $network );
 517                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 518                         if ( $bits == 0 ) {
 519                                 $network = 0;
 520                         } else {
 521                                 $network &= ~( ( 1 << ( 32 - $bits ) ) - 1);
 522                         }
 523                         # Convert to unsigned
 524                         if ( $network < 0 ) {
 525                                 $network += pow( 2, 32 );
 526                         }
 527                 } else {
 528                         $network = false;
 529                         $bits = false;
 530                 }
 531                 return array( $network, $bits );
 532         }
 533
 534         /**
 535          * Given a string range in a number of formats, return the start and end of
 536          * the range in hexadecimal.
 537          *
 538          * Formats are:
 539          *     1.2.3.4/24          CIDR
 540          *     1.2.3.4 - 1.2.3.5   Explicit range
 541          *     1.2.3.4             Single IP
 542          *
 543          *     2001:0db8:85a3::7344/96                                   CIDR
 544          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 545          *     2001:0db8:85a3::7344                                      Single IP
 546          * @param string $range IP range
 547          * @return array(string, int)
 548          */
 549         public static function parseRange( $range ) {
 550                 // Use IPv6 functions if needed
 551                 if ( self::isIPv6( $range ) ) {
 552                         return self::parseRange6( $range );
 553                 }
 554                 if ( strpos( $range, '/' ) !== false ) {
 555                         # CIDR
 556                         list( $network, $bits ) = self::parseCIDR( $range );
 557                         if ( $network === false ) {
 558                                 $start = $end = false;
 559                         } else {
 560                                 $start = sprintf( '%08X', $network );
 561                                 $end = sprintf( '%08X', $network + pow( 2, ( 32 - $bits ) ) - 1 );
 562                         }
 563                 } elseif ( strpos( $range, '-' ) !== false ) {
 564                         # Explicit range
 565                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 566                         if( self::isIPAddress( $start ) && self::isIPAddress( $end ) ) {
 567                                 $start = self::toUnsigned( $start );
 568                                 $end = self::toUnsigned( $end );
 569                                 if ( $start > $end ) {
 570                                         $start = $end = false;
 571                                 } else {
 572                                         $start = sprintf( '%08X', $start );
 573                                         $end = sprintf( '%08X', $end );
 574                                 }
 575                         } else {
 576                                 $start = $end = false;
 577                         }
 578                 } else {
 579                         # Single IP
 580                         $start = $end = self::toHex( $range );
 581                 }
 582                 if ( $start === false || $end === false ) {
 583                         return array( false, false );
 584                 } else {
 585                         return array( $start, $end );
 586                 }
 587         }
 588
 589         /**
 590          * Determine if a given IPv4/IPv6 address is in a given CIDR network
 591          * @param $addr The address to check against the given range.
 592          * @param $range The range to check the given address against.
 593          * @return bool Whether or not the given address is in the given range.
 594          */
 595         public static function isInRange( $addr, $range ) {
 596                 $hexIP = self::toHex( $addr );
 597                 list( $start, $end ) = self::parseRange( $range );
 598                 return ( strcmp( $hexIP, $start ) >= 0 &&
 599                         strcmp( $hexIP, $end ) <= 0 );
 600         }
 601
 602         /**
 603          * Convert some unusual representations of IPv4 addresses to their
 604          * canonical dotted quad representation.
 605          *
 606          * This currently only checks a few IPV4-to-IPv6 related cases.  More
 607          * unusual representations may be added later.
 608          *
 609          * @param $addr something that might be an IP address
 610          * @return valid dotted quad IPv4 address or null
 611          */
 612         public static function canonicalize( $addr ) {
 613                 if ( self::isValid( $addr ) ) {
 614                         return $addr;
 615                 }
 616
 617                 // Turn mapped addresses from ::ce:ffff:1.2.3.4 to 1.2.3.4
 618                 if ( strpos( $addr, ':' ) !== false && strpos( $addr, '.' ) !== false ) {
 619                         $addr = substr( $addr, strrpos( $addr, ':' ) + 1 );
 620                         if( self::isIPv4( $addr ) ) {
 621                                 return $addr;
 622                         }
 623                 }
 624
 625                 // IPv6 loopback address
 626                 $m = array();
 627                 if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) ) {
 628                         return '127.0.0.1';
 629                 }
 630
 631                 // IPv4-mapped and IPv4-compatible IPv6 addresses
 632                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) ) {
 633                         return $m[1];
 634                 }
 635                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD . ':' . RE_IPV6_WORD . '$/i', $addr, $m ) ) {
 636                         return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 637                 }
 638
 639                 return null;  // give up
 640         }
 641 }