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 IPv4 address 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 address is made up of 8 words (each x0000 to xFFFF).
  34 // However, the "::" abbreviation can be used on consecutive x0000 words.
  35 define( 'RE_IPV6_WORD', '([0-9A-Fa-f]{1,4})' );
  36 define( 'RE_IPV6_PREFIX', '(12[0-8]|1[01][0-9]|[1-9]?\d)');
  37 define( 'RE_IPV6_ADD',
  38         '(?:' . // starts with "::" (including "::")
  39                 ':(?::|(?::' . RE_IPV6_WORD . '){1,7})' .
  40         '|' . // ends with "::" (except "::")
  41                 RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){0,6}::' .
  42         '|' . // contains one "::" in the middle, ending in "::WORD"
  43                 RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){0,5}' . '::' . RE_IPV6_WORD .
  44         '|' . // contains one "::" in the middle, not ending in "::WORD" (regex for PCRE 4.0+)
  45                 RE_IPV6_WORD . '(?::(?P<abn>:(?P<iabn>))?' . RE_IPV6_WORD . '(?!:(?P=abn))){1,5}' .
  46                         ':' . RE_IPV6_WORD . '(?P=iabn)' .
  47                 // NOTE: (?!(?P=abn)) fails iff "::" used twice; (?P=iabn) passes iff a "::" was found.
  48         '|' . // contains no "::"
  49                 RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){7}' .
  50         ')'
  51         // NOTE: With PCRE 7.2+, we can combine the two '"::" in the middle' cases into:
  52         //              RE_IPV6_WORD . '(?::((?(-1)|:))?' . RE_IPV6_WORD . '){1,6}(?(-2)|^)'
  53         // This also improves regex concatenation by using relative references.
  54 );
  55 // An IPv6 block is an IP address and a prefix (d1 to d128)
  56 define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );
  57 // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  58 define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  59 define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  60
  61 // This might be useful for regexps used elsewhere, matches any IPv6 or IPv6 address or network
  62 define( 'IP_ADDRESS_STRING',
  63         '(?:' .
  64                 RE_IP_ADD . '(?:\/' . RE_IP_PREFIX . ')?' . // IPv4
  65         '|' .
  66                 RE_IPV6_ADD . '(?:\/' . RE_IPV6_PREFIX . ')?' . // IPv6
  67         ')'
  68 );
  69
  70 /**
  71  * A collection of public static functions to play with IP address
  72  * and IP blocks.
  73  */
  74 class IP {
  75         /**
  76          * Determine if a string is as valid IP address or network (CIDR prefix).
  77          * SIIT IPv4-translated addresses are rejected.
  78          * Note: canonicalize() tries to convert translated addresses to IPv4.
  79          *
  80          * @param $ip String: possible IP address
  81          * @return Boolean
  82          */
  83         public static function isIPAddress( $ip ) {
  84                 return (bool)preg_match( '/^' . IP_ADDRESS_STRING . '$/', $ip );
  85         }
  86
  87         /**
  88          * Given a string, determine if it as valid IP in IPv6 only.
  89          * Note: Unlike isValid(), this looks for networks too.
  90          *
  91          * @param $ip String: possible IP address
  92          * @return Boolean
  93          */
  94         public static function isIPv6( $ip ) {
  95                 return (bool)preg_match( '/^' . RE_IPV6_ADD . '(?:\/' . RE_IPV6_PREFIX . ')?$/', $ip );
  96         }
  97
  98         /**
  99          * Given a string, determine if it as valid IP in IPv4 only.
 100          * Note: Unlike isValid(), this looks for networks too.
 101          *
 102          * @param $ip String: possible IP address
 103          * @return Boolean
 104          */
 105         public static function isIPv4( $ip ) {
 106                 return (bool)preg_match( '/^' . RE_IP_ADD . '(?:\/' . RE_IP_PREFIX . ')?$/', $ip );
 107         }
 108
 109         /**
 110          * Validate an IP address. Ranges are NOT considered valid.
 111          * SIIT IPv4-translated addresses are rejected.
 112          * Note: canonicalize() tries to convert translated addresses to IPv4.
 113          *
 114          * @param $ip String
 115          * @return Boolean: True if it is valid.
 116          */
 117         public static function isValid( $ip ) {
 118                 return ( preg_match( '/^' . RE_IP_ADD . '$/', $ip )
 119                         || preg_match( '/^' . RE_IPV6_ADD . '$/', $ip ) );
 120         }
 121
 122         /**
 123          * Validate an IP Block (valid address WITH a valid prefix).
 124          * SIIT IPv4-translated addresses are rejected.
 125          * Note: canonicalize() tries to convert translated addresses to IPv4.
 126          *
 127          * @param $ipblock String
 128          * @return Boolean: True if it is valid.
 129          */
 130         public static function isValidBlock( $ipblock ) {
 131                 return ( preg_match( '/^' . RE_IPV6_BLOCK . '$/', $ipblock )
 132                         || preg_match( '/^' . RE_IP_BLOCK . '$/', $ipblock ) );
 133         }
 134
 135         /**
 136          * Convert an IP into a nice standard form.
 137          * IPv6 addresses in octet notation are expanded to 8 words.
 138          * IPv4 addresses are just trimmed.
 139          *
 140          * @param $ip String: IP address in quad or octet form (CIDR or not).
 141          * @return String
 142          */
 143         public static function sanitizeIP( $ip ) {
 144                 $ip = trim( $ip );
 145                 if ( $ip === '' ) {
 146                         return null;
 147                 }
 148                 if ( self::isIPv4( $ip ) || !self::isIPv6( $ip ) ) {
 149                         return $ip; // nothing else to do for IPv4 addresses or invalid ones
 150                 }
 151                 // Remove any whitespaces, convert to upper case
 152                 $ip = strtoupper( $ip );
 153                 // Expand zero abbreviations
 154                 $abbrevPos = strpos( $ip, '::' );
 155                 if ( $abbrevPos !== false ) {
 156                         // We know this is valid IPv6. Find the last index of the
 157                         // address before any CIDR number (e.g. "a:b:c::/24").
 158                         $CIDRStart = strpos( $ip, "/" );
 159                         $addressEnd = ( $CIDRStart !== false )
 160                                 ? $CIDRStart - 1
 161                                 : strlen( $ip ) - 1;
 162                         // If the '::' is at the beginning...
 163                         if ( $abbrevPos == 0 ) {
 164                                 $repeat = '0:';
 165                                 $extra = ( $ip == '::' ) ? '0' : ''; // for the address '::'
 166                                 $pad = 9; // 7+2 (due to '::')
 167                         // If the '::' is at the end...
 168                         } elseif ( $abbrevPos == ( $addressEnd - 1 ) ) {
 169                                 $repeat = ':0';
 170                                 $extra = '';
 171                                 $pad = 9; // 7+2 (due to '::')
 172                         // If the '::' is in the middle...
 173                         } else {
 174                                 $repeat = ':0';
 175                                 $extra = ':';
 176                                 $pad = 8; // 6+2 (due to '::')
 177                         }
 178                         $ip = str_replace( '::',
 179                                 str_repeat( $repeat, $pad - substr_count( $ip, ':' ) ) . $extra,
 180                                 $ip
 181                         );
 182                 }
 183                 // Remove leading zereos from each bloc as needed
 184                 $ip = preg_replace( '/(^|:)0+(' . RE_IPV6_WORD . ')/', '$1$2', $ip );
 185                 return $ip;
 186         }
 187
 188         /**
 189          * Given an unsigned integer, returns an IPv6 address in octet notation
 190          *
 191          * @param $ip_int String: IP address.
 192          * @return String
 193          */
 194         public static function toOctet( $ip_int ) {
 195                 return self::hexToOctet( wfBaseConvert( $ip_int, 10, 16, 32, false ) );
 196         }
 197
 198         /**
 199          * Convert an IPv4 or IPv6 hexadecimal representation back to readable format
 200          *
 201          * @param $hex String: number, with "v6-" prefix if it is IPv6
 202          * @return String: quad-dotted (IPv4) or octet notation (IPv6)
 203          */
 204         public static function formatHex( $hex ) {
 205                 if ( substr( $hex, 0, 3 ) == 'v6-' ) { // IPv6
 206                         return self::hexToOctet( substr( $hex, 3 ) );
 207                 } else { // IPv4
 208                         return self::hexToQuad( $hex );
 209                 }
 210         }
 211
 212         /**
 213          * Converts a hexadecimal number to an IPv6 address in octet notation
 214          *
 215          * @param $ip_hex String: pure hex (no v6- prefix)
 216          * @return String (of format a:b:c:d:e:f:g:h)
 217          */
 218         public static function hexToOctet( $ip_hex ) {
 219                 // Pad hex to 32 chars (128 bits)
 220                 $ip_hex = str_pad( strtoupper( $ip_hex ), 32, '0', STR_PAD_LEFT );
 221                 // Separate into 8 words
 222                 $ip_oct = substr( $ip_hex, 0, 4 );
 223                 for ( $n = 1; $n < 8; $n++ ) {
 224                         $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 225                 }
 226                 // NO leading zeroes
 227                 $ip_oct = preg_replace( '/(^|:)0+(' . RE_IPV6_WORD . ')/', '$1$2', $ip_oct );
 228                 return $ip_oct;
 229         }
 230
 231         /**
 232          * Converts a hexadecimal number to an IPv4 address in quad-dotted notation
 233          *
 234          * @param $ip_hex String: pure hex
 235          * @return String (of format a.b.c.d)
 236          */
 237         public static function hexToQuad( $ip_hex ) {
 238                 // Pad hex to 8 chars (32 bits)
 239                 $ip_hex = str_pad( strtoupper( $ip_hex ), 8, '0', STR_PAD_LEFT );
 240                 // Separate into four quads
 241                 $s = '';
 242                 for ( $i = 0; $i < 4; $i++ ) {
 243                         if ( $s !== '' ) {
 244                                 $s .= '.';
 245                         }
 246                         $s .= base_convert( substr( $ip_hex, $i * 2, 2 ), 16, 10 );
 247                 }
 248                 return $s;
 249         }
 250
 251         /**
 252          * Determine if an IP address really is an IP address, and if it is public,
 253          * i.e. not RFC 1918 or similar
 254          * Comes from ProxyTools.php
 255          *
 256          * @param $ip String
 257          * @return Boolean
 258          */
 259         public static function isPublic( $ip ) {
 260                 if ( self::isIPv6( $ip ) ) {
 261                         return self::isPublic6( $ip );
 262                 }
 263                 $n = self::toUnsigned( $ip );
 264                 if ( !$n ) {
 265                         return false;
 266                 }
 267
 268                 // ip2long accepts incomplete addresses, as well as some addresses
 269                 // followed by garbage characters. Check that it's really valid.
 270                 if ( $ip != long2ip( $n ) ) {
 271                         return false;
 272                 }
 273
 274                 static $privateRanges = false;
 275                 if ( !$privateRanges ) {
 276                         $privateRanges = array(
 277                                 array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
 278                                 array( '172.16.0.0',  '172.31.255.255' ),   #     "
 279                                 array( '192.168.0.0', '192.168.255.255' ),  #     "
 280                                 array( '0.0.0.0',     '0.255.255.255' ),    # this network
 281                                 array( '127.0.0.0',   '127.255.255.255' ),  # loopback
 282                         );
 283                 }
 284
 285                 foreach ( $privateRanges as $r ) {
 286                         $start = self::toUnsigned( $r[0] );
 287                         $end = self::toUnsigned( $r[1] );
 288                         if ( $n >= $start && $n <= $end ) {
 289                                 return false;
 290                         }
 291                 }
 292                 return true;
 293         }
 294
 295         /**
 296          * Determine if an IPv6 address really is an IP address, and if it is public,
 297          * i.e. not RFC 4193 or similar
 298          *
 299          * @param $ip String
 300          * @return Boolean
 301          */
 302         private static function isPublic6( $ip ) {
 303                 static $privateRanges = false;
 304                 if ( !$privateRanges ) {
 305                         $privateRanges = array(
 306                                 array( 'fc::', 'fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff' ), # RFC 4193 (local)
 307                                 array( '0:0:0:0:0:0:0:1', '0:0:0:0:0:0:0:1' ), # loopback
 308                         );
 309                 }
 310                 $n = self::toHex( $ip );
 311                 foreach ( $privateRanges as $r ) {
 312                         $start = self::toHex( $r[0] );
 313                         $end = self::toHex( $r[1] );
 314                         if ( $n >= $start && $n <= $end ) {
 315                                 return false;
 316                         }
 317                 }
 318                 return true;
 319         }
 320
 321         /**
 322          * Return a zero-padded upper case hexadecimal representation of an IP address.
 323          *
 324          * Hexadecimal addresses are used because they can easily be extended to
 325          * IPv6 support. To separate the ranges, the return value from this
 326          * function for an IPv6 address will be prefixed with "v6-", a non-
 327          * hexadecimal string which sorts after the IPv4 addresses.
 328          *
 329          * @param $ip String: quad dotted/octet IP address.
 330          * @return String
 331          */
 332         public static function toHex( $ip ) {
 333                 if ( self::isIPv6( $ip ) ) {
 334                         $n = 'v6-' . self::IPv6ToRawHex( $ip );
 335                 } else {
 336                         $n = self::toUnsigned( $ip );
 337                         if ( $n !== false ) {
 338                                 $n = wfBaseConvert( $n, 10, 16, 8, false );
 339                         }
 340                 }
 341                 return $n;
 342         }
 343
 344         /**
 345          * Given an IPv6 address in octet notation, returns a pure hex string.
 346          *
 347          * @param $ip String: octet ipv6 IP address.
 348          * @return String: pure hex (uppercase)
 349          */
 350         private static function IPv6ToRawHex( $ip ) {
 351                 $ip = self::sanitizeIP( $ip );
 352                 if ( !$ip ) {
 353                         return null;
 354                 }
 355                 $r_ip = '';
 356                 foreach ( explode( ':', $ip ) as $v ) {
 357                         $r_ip .= str_pad( $v, 4, 0, STR_PAD_LEFT );
 358                 }
 359                 return $r_ip;
 360         }
 361
 362         /**
 363          * Given an IP address in dotted-quad/octet notation, returns an unsigned integer.
 364          * Like ip2long() except that it actually works and has a consistent error return value.
 365          * Comes from ProxyTools.php
 366          *
 367          * @param $ip String: quad dotted IP address.
 368          * @return Mixed: string/int/false
 369          */
 370         public static function toUnsigned( $ip ) {
 371                 if ( self::isIPv6( $ip ) ) {
 372                         $n = self::toUnsigned6( $ip );
 373                 } else {
 374                         $n = ip2long( $ip );
 375                         if ( $n < 0 ) {
 376                                 $n += pow( 2, 32 );
 377                         }
 378                 }
 379                 return $n;
 380         }
 381
 382         private static function toUnsigned6( $ip ) {
 383                 return wfBaseConvert( self::IPv6ToRawHex( $ip ), 16, 10 );
 384         }
 385
 386         /**
 387          * Convert a network specification in CIDR notation
 388          * to an integer network and a number of bits
 389          *
 390          * @param $range String: IP with CIDR prefix
 391          * @return array(int or string, int)
 392          */
 393         public static function parseCIDR( $range ) {
 394                 if ( self::isIPv6( $range ) ) {
 395                         return self::parseCIDR6( $range );
 396                 }
 397                 $parts = explode( '/', $range, 2 );
 398                 if ( count( $parts ) != 2 ) {
 399                         return array( false, false );
 400                 }
 401                 list( $network, $bits ) = $parts;
 402                 $network = ip2long( $network );
 403                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 404                         if ( $bits == 0 ) {
 405                                 $network = 0;
 406                         } else {
 407                                 $network &= ~( ( 1 << ( 32 - $bits ) ) - 1);
 408                         }
 409                         # Convert to unsigned
 410                         if ( $network < 0 ) {
 411                                 $network += pow( 2, 32 );
 412                         }
 413                 } else {
 414                         $network = false;
 415                         $bits = false;
 416                 }
 417                 return array( $network, $bits );
 418         }
 419
 420         /**
 421          * Given a string range in a number of formats,
 422          * return the start and end of the range in hexadecimal.
 423          *
 424          * Formats are:
 425          *     1.2.3.4/24          CIDR
 426          *     1.2.3.4 - 1.2.3.5   Explicit range
 427          *     1.2.3.4             Single IP
 428          *
 429          *     2001:0db8:85a3::7344/96                                   CIDR
 430          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 431          *     2001:0db8:85a3::7344                                      Single IP
 432          * @param $range String: IP range
 433          * @return array(string, string)
 434          */
 435         public static function parseRange( $range ) {
 436                 // CIDR notation
 437                 if ( strpos( $range, '/' ) !== false ) {
 438                         if ( self::isIPv6( $range ) ) {
 439                                 return self::parseRange6( $range );
 440                         }
 441                         list( $network, $bits ) = self::parseCIDR( $range );
 442                         if ( $network === false ) {
 443                                 $start = $end = false;
 444                         } else {
 445                                 $start = sprintf( '%08X', $network );
 446                                 $end = sprintf( '%08X', $network + pow( 2, ( 32 - $bits ) ) - 1 );
 447                         }
 448                 // Explicit range
 449                 } elseif ( strpos( $range, '-' ) !== false ) {
 450                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 451                         if ( self::isIPv6( $start ) && self::isIPv6( $end ) ) {
 452                                 return self::parseRange6( $range );
 453                         }
 454                         if ( self::isIPv4( $start ) && self::isIPv4( $end ) ) {
 455                                 $start = self::toUnsigned( $start );
 456                                 $end = self::toUnsigned( $end );
 457                                 if ( $start > $end ) {
 458                                         $start = $end = false;
 459                                 } else {
 460                                         $start = sprintf( '%08X', $start );
 461                                         $end = sprintf( '%08X', $end );
 462                                 }
 463                         } else {
 464                                 $start = $end = false;
 465                         }
 466                 } else {
 467                         # Single IP
 468                         $start = $end = self::toHex( $range );
 469                 }
 470                 if ( $start === false || $end === false ) {
 471                         return array( false, false );
 472                 } else {
 473                         return array( $start, $end );
 474                 }
 475         }
 476
 477         /**
 478          * Convert a network specification in IPv6 CIDR notation to an
 479          * integer network and a number of bits
 480          *
 481          * @return array(string, int)
 482          */
 483         private static function parseCIDR6( $range ) {
 484                 # Explode into <expanded IP,range>
 485                 $parts = explode( '/', IP::sanitizeIP( $range ), 2 );
 486                 if ( count( $parts ) != 2 ) {
 487                         return array( false, false );
 488                 }
 489                 list( $network, $bits ) = $parts;
 490                 $network = self::IPv6ToRawHex( $network );
 491                 if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 128 ) {
 492                         if ( $bits == 0 ) {
 493                                 $network = "0";
 494                         } else {
 495                                 # Native 32 bit functions WONT work here!!!
 496                                 # Convert to a padded binary number
 497                                 $network = wfBaseConvert( $network, 16, 2, 128 );
 498                                 # Truncate the last (128-$bits) bits and replace them with zeros
 499                                 $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
 500                                 # Convert back to an integer
 501                                 $network = wfBaseConvert( $network, 2, 10 );
 502                         }
 503                 } else {
 504                         $network = false;
 505                         $bits = false;
 506                 }
 507                 return array( $network, (int)$bits );
 508         }
 509
 510         /**
 511          * Given a string range in a number of formats, return the
 512          * start and end of the range in hexadecimal. For IPv6.
 513          *
 514          * Formats are:
 515          *     2001:0db8:85a3::7344/96                                   CIDR
 516          *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 517          *     2001:0db8:85a3::7344/96                                   Single IP
 518          * @return array(string, string)
 519          */
 520         private static function parseRange6( $range ) {
 521                 # Expand any IPv6 IP
 522                 $range = IP::sanitizeIP( $range );
 523                 // CIDR notation...
 524                 if ( strpos( $range, '/' ) !== false ) {
 525                         list( $network, $bits ) = self::parseCIDR6( $range );
 526                         if ( $network === false ) {
 527                                 $start = $end = false;
 528                         } else {
 529                                 $start = wfBaseConvert( $network, 10, 16, 32, false );
 530                                 # Turn network to binary (again)
 531                                 $end = wfBaseConvert( $network, 10, 2, 128 );
 532                                 # Truncate the last (128-$bits) bits and replace them with ones
 533                                 $end = str_pad( substr( $end, 0, $bits ), 128, 1, STR_PAD_RIGHT );
 534                                 # Convert to hex
 535                                 $end = wfBaseConvert( $end, 2, 16, 32, false );
 536                                 # see toHex() comment
 537                                 $start = "v6-$start";
 538                                 $end = "v6-$end";
 539                         }
 540                 // Explicit range notation...
 541                 } elseif ( strpos( $range, '-' ) !== false ) {
 542                         list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 543                         $start = self::toUnsigned6( $start );
 544                         $end = self::toUnsigned6( $end );
 545                         if ( $start > $end ) {
 546                                 $start = $end = false;
 547                         } else {
 548                                 $start = wfBaseConvert( $start, 10, 16, 32, false );
 549                                 $end = wfBaseConvert( $end, 10, 16, 32, false );
 550                         }
 551                         # see toHex() comment
 552                         $start = "v6-$start";
 553                         $end = "v6-$end";
 554                 } else {
 555                         # Single IP
 556                         $start = $end = self::toHex( $range );
 557                 }
 558                 if ( $start === false || $end === false ) {
 559                         return array( false, false );
 560                 } else {
 561                         return array( $start, $end );
 562                 }
 563         }
 564
 565         /**
 566          * Determine if a given IPv4/IPv6 address is in a given CIDR network
 567          *
 568          * @param $addr String: the address to check against the given range.
 569          * @param $range String: the range to check the given address against.
 570          * @return Boolean: whether or not the given address is in the given range.
 571          */
 572         public static function isInRange( $addr, $range ) {
 573                 $hexIP = self::toHex( $addr );
 574                 list( $start, $end ) = self::parseRange( $range );
 575                 return ( strcmp( $hexIP, $start ) >= 0 &&
 576                         strcmp( $hexIP, $end ) <= 0 );
 577         }
 578
 579         /**
 580          * Convert some unusual representations of IPv4 addresses to their
 581          * canonical dotted quad representation.
 582          *
 583          * This currently only checks a few IPV4-to-IPv6 related cases.  More
 584          * unusual representations may be added later.
 585          *
 586          * @param $addr String: something that might be an IP address
 587          * @return String: valid dotted quad IPv4 address or null
 588          */
 589         public static function canonicalize( $addr ) {
 590                 if ( self::isValid( $addr ) ) {
 591                         return $addr;
 592                 }
 593                 // Turn mapped addresses from ::ce:ffff:1.2.3.4 to 1.2.3.4
 594                 if ( strpos( $addr, ':' ) !== false && strpos( $addr, '.' ) !== false ) {
 595                         $addr = substr( $addr, strrpos( $addr, ':' ) + 1 );
 596                         if ( self::isIPv4( $addr ) ) {
 597                                 return $addr;
 598                         }
 599                 }
 600                 // IPv6 loopback address
 601                 $m = array();
 602                 if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) ) {
 603                         return '127.0.0.1';
 604                 }
 605                 // IPv4-mapped and IPv4-compatible IPv6 addresses
 606                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) ) {
 607                         return $m[1];
 608                 }
 609                 if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD .
 610                         ':' . RE_IPV6_WORD . '$/i', $addr, $m ) )
 611                 {
 612                         return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 613                 }
 614
 615                 return null;  // give up
 616         }
 617
 618         /**
 619          * Gets rid of uneeded numbers in quad-dotted/octet IP strings
 620          * For example, 127.111.113.151/24 -> 127.111.113.0/24
 621          * @param $range String: IP address to normalize
 622          * @return string
 623          */
 624         public static function sanitizeRange( $range ){
 625                 list( /*...*/, $bits ) = self::parseCIDR( $range );
 626                 list( $start, /*...*/ ) = self::parseRange( $range );
 627                 $start = self::formatHex( $start );
 628                 return "$start/$bits";
 629         }
 630 }