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   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 Antoine Musso "<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 (the ^ makes the test fail if none found)
  43          RE_IPV6_WORD . '(?::((?(-1)|:))?' . RE_IPV6_WORD . '){1,6}(?(-2)|^)' .
  44      '|' . // contains no "::"
  45          RE_IPV6_WORD . '(?::' . RE_IPV6_WORD . '){7}' .
  46      ')'
  47  );
  48  // An IPv6 block is an IP address and a prefix (d1 to d128)
  49  define( 'RE_IPV6_BLOCK', RE_IPV6_ADD . '\/' . RE_IPV6_PREFIX );
  50  // For IPv6 canonicalization (NOT for strict validation; these are quite lax!)
  51  define( 'RE_IPV6_GAP', ':(?:0+:)*(?::(?:0+:)*)?' );
  52  define( 'RE_IPV6_V4_PREFIX', '0*' . RE_IPV6_GAP . '(?:ffff:)?' );
  53  
  54  // This might be useful for regexps used elsewhere, matches any IPv6 or IPv6 address or network
  55  define( 'IP_ADDRESS_STRING',
  56      '(?:' .
  57          RE_IP_ADD . '(?:\/' . RE_IP_PREFIX . ')?' . // IPv4
  58      '|' .
  59          RE_IPV6_ADD . '(?:\/' . RE_IPV6_PREFIX . ')?' . // IPv6
  60      ')'
  61  );
  62  
  63  /**
  64   * A collection of public static functions to play with IP address
  65   * and IP blocks.
  66   */
  67  class IP {
  68      /** @var IPSet */
  69      private static $proxyIpSet = null;
  70  
  71      /**
  72       * Determine if a string is as valid IP address or network (CIDR prefix).
  73       * SIIT IPv4-translated addresses are rejected.
  74       * Note: canonicalize() tries to convert translated addresses to IPv4.
  75       *
  76       * @param string $ip Possible IP address
  77       * @return bool
  78       */
  79  	public static function isIPAddress( $ip ) {
  80          return (bool)preg_match( '/^' . IP_ADDRESS_STRING . '$/', $ip );
  81      }
  82  
  83      /**
  84       * Given a string, determine if it as valid IP in IPv6 only.
  85       * Note: Unlike isValid(), this looks for networks too.
  86       *
  87       * @param string $ip Possible IP address
  88       * @return bool
  89       */
  90  	public static function isIPv6( $ip ) {
  91          return (bool)preg_match( '/^' . RE_IPV6_ADD . '(?:\/' . RE_IPV6_PREFIX . ')?$/', $ip );
  92      }
  93  
  94      /**
  95       * Given a string, determine if it as valid IP in IPv4 only.
  96       * Note: Unlike isValid(), this looks for networks too.
  97       *
  98       * @param string $ip Possible IP address
  99       * @return bool
 100       */
 101  	public static function isIPv4( $ip ) {
 102          return (bool)preg_match( '/^' . RE_IP_ADD . '(?:\/' . RE_IP_PREFIX . ')?$/', $ip );
 103      }
 104  
 105      /**
 106       * Validate an IP address. Ranges are NOT considered valid.
 107       * SIIT IPv4-translated addresses are rejected.
 108       * Note: canonicalize() tries to convert translated addresses to IPv4.
 109       *
 110       * @param string $ip
 111       * @return bool True if it is valid
 112       */
 113  	public static function isValid( $ip ) {
 114          return ( preg_match( '/^' . RE_IP_ADD . '$/', $ip )
 115              || preg_match( '/^' . RE_IPV6_ADD . '$/', $ip ) );
 116      }
 117  
 118      /**
 119       * Validate an IP Block (valid address WITH a valid prefix).
 120       * SIIT IPv4-translated addresses are rejected.
 121       * Note: canonicalize() tries to convert translated addresses to IPv4.
 122       *
 123       * @param string $ipblock
 124       * @return bool True if it is valid
 125       */
 126  	public static function isValidBlock( $ipblock ) {
 127          return ( preg_match( '/^' . RE_IPV6_BLOCK . '$/', $ipblock )
 128              || preg_match( '/^' . RE_IP_BLOCK . '$/', $ipblock ) );
 129      }
 130  
 131      /**
 132       * Convert an IP into a verbose, uppercase, normalized form.
 133       * IPv6 addresses in octet notation are expanded to 8 words.
 134       * IPv4 addresses are just trimmed.
 135       *
 136       * @param string $ip IP address in quad or octet form (CIDR or not).
 137       * @return string
 138       */
 139  	public static function sanitizeIP( $ip ) {
 140          $ip = trim( $ip );
 141          if ( $ip === '' ) {
 142              return null;
 143          }
 144          if ( self::isIPv4( $ip ) || !self::isIPv6( $ip ) ) {
 145              return $ip; // nothing else to do for IPv4 addresses or invalid ones
 146          }
 147          // Remove any whitespaces, convert to upper case
 148          $ip = strtoupper( $ip );
 149          // Expand zero abbreviations
 150          $abbrevPos = strpos( $ip, '::' );
 151          if ( $abbrevPos !== false ) {
 152              // We know this is valid IPv6. Find the last index of the
 153              // address before any CIDR number (e.g. "a:b:c::/24").
 154              $CIDRStart = strpos( $ip, "/" );
 155              $addressEnd = ( $CIDRStart !== false )
 156                  ? $CIDRStart - 1
 157                  : strlen( $ip ) - 1;
 158              // If the '::' is at the beginning...
 159              if ( $abbrevPos == 0 ) {
 160                  $repeat = '0:';
 161                  $extra = ( $ip == '::' ) ? '0' : ''; // for the address '::'
 162                  $pad = 9; // 7+2 (due to '::')
 163              // If the '::' is at the end...
 164              } elseif ( $abbrevPos == ( $addressEnd - 1 ) ) {
 165                  $repeat = ':0';
 166                  $extra = '';
 167                  $pad = 9; // 7+2 (due to '::')
 168              // If the '::' is in the middle...
 169              } else {
 170                  $repeat = ':0';
 171                  $extra = ':';
 172                  $pad = 8; // 6+2 (due to '::')
 173              }
 174              $ip = str_replace( '::',
 175                  str_repeat( $repeat, $pad - substr_count( $ip, ':' ) ) . $extra,
 176                  $ip
 177              );
 178          }
 179          // Remove leading zeros from each bloc as needed
 180          $ip = preg_replace( '/(^|:)0+(' . RE_IPV6_WORD . ')/', '$1$2', $ip );
 181  
 182          return $ip;
 183      }
 184  
 185      /**
 186       * Prettify an IP for display to end users.
 187       * This will make it more compact and lower-case.
 188       *
 189       * @param string $ip
 190       * @return string
 191       */
 192  	public static function prettifyIP( $ip ) {
 193          $ip = self::sanitizeIP( $ip ); // normalize (removes '::')
 194          if ( self::isIPv6( $ip ) ) {
 195              // Split IP into an address and a CIDR
 196              if ( strpos( $ip, '/' ) !== false ) {
 197                  list( $ip, $cidr ) = explode( '/', $ip, 2 );
 198              } else {
 199                  list( $ip, $cidr ) = array( $ip, '' );
 200              }
 201              // Get the largest slice of words with multiple zeros
 202              $offset = 0;
 203              $longest = $longestPos = false;
 204              while ( preg_match(
 205                  '!(?:^|:)0(?::0)+(?:$|:)!', $ip, $m, PREG_OFFSET_CAPTURE, $offset
 206              ) ) {
 207                  list( $match, $pos ) = $m[0]; // full match
 208                  if ( strlen( $match ) > strlen( $longest ) ) {
 209                      $longest = $match;
 210                      $longestPos = $pos;
 211                  }
 212                  $offset = ( $pos + strlen( $match ) ); // advance
 213              }
 214              if ( $longest !== false ) {
 215                  // Replace this portion of the string with the '::' abbreviation
 216                  $ip = substr_replace( $ip, '::', $longestPos, strlen( $longest ) );
 217              }
 218              // Add any CIDR back on
 219              if ( $cidr !== '' ) {
 220                  $ip = "{$ip}/{$cidr}";
 221              }
 222              // Convert to lower case to make it more readable
 223              $ip = strtolower( $ip );
 224          }
 225  
 226          return $ip;
 227      }
 228  
 229      /**
 230       * Given a host/port string, like one might find in the host part of a URL
 231       * per RFC 2732, split the hostname part and the port part and return an
 232       * array with an element for each. If there is no port part, the array will
 233       * have false in place of the port. If the string was invalid in some way,
 234       * false is returned.
 235       *
 236       * This was easy with IPv4 and was generally done in an ad-hoc way, but
 237       * with IPv6 it's somewhat more complicated due to the need to parse the
 238       * square brackets and colons.
 239       *
 240       * A bare IPv6 address is accepted despite the lack of square brackets.
 241       *
 242       * @param string $both The string with the host and port
 243       * @return array
 244       */
 245  	public static function splitHostAndPort( $both ) {
 246          if ( substr( $both, 0, 1 ) === '[' ) {
 247              if ( preg_match( '/^\[(' . RE_IPV6_ADD . ')\](?::(?P<port>\d+))?$/', $both, $m ) ) {
 248                  if ( isset( $m['port'] ) ) {
 249                      return array( $m[1], intval( $m['port'] ) );
 250                  } else {
 251                      return array( $m[1], false );
 252                  }
 253              } else {
 254                  // Square bracket found but no IPv6
 255                  return false;
 256              }
 257          }
 258          $numColons = substr_count( $both, ':' );
 259          if ( $numColons >= 2 ) {
 260              // Is it a bare IPv6 address?
 261              if ( preg_match( '/^' . RE_IPV6_ADD . '$/', $both ) ) {
 262                  return array( $both, false );
 263              } else {
 264                  // Not valid IPv6, but too many colons for anything else
 265                  return false;
 266              }
 267          }
 268          if ( $numColons >= 1 ) {
 269              // Host:port?
 270              $bits = explode( ':', $both );
 271              if ( preg_match( '/^\d+/', $bits[1] ) ) {
 272                  return array( $bits[0], intval( $bits[1] ) );
 273              } else {
 274                  // Not a valid port
 275                  return false;
 276              }
 277          }
 278  
 279          // Plain hostname
 280          return array( $both, false );
 281      }
 282  
 283      /**
 284       * Given a host name and a port, combine them into host/port string like
 285       * you might find in a URL. If the host contains a colon, wrap it in square
 286       * brackets like in RFC 2732. If the port matches the default port, omit
 287       * the port specification
 288       *
 289       * @param string $host
 290       * @param int $port
 291       * @param bool|int $defaultPort
 292       * @return string
 293       */
 294  	public static function combineHostAndPort( $host, $port, $defaultPort = false ) {
 295          if ( strpos( $host, ':' ) !== false ) {
 296              $host = "[$host]";
 297          }
 298          if ( $defaultPort !== false && $port == $defaultPort ) {
 299              return $host;
 300          } else {
 301              return "$host:$port";
 302          }
 303      }
 304  
 305      /**
 306       * Convert an IPv4 or IPv6 hexadecimal representation back to readable format
 307       *
 308       * @param string $hex Number, with "v6-" prefix if it is IPv6
 309       * @return string Quad-dotted (IPv4) or octet notation (IPv6)
 310       */
 311  	public static function formatHex( $hex ) {
 312          if ( substr( $hex, 0, 3 ) == 'v6-' ) { // IPv6
 313              return self::hexToOctet( substr( $hex, 3 ) );
 314          } else { // IPv4
 315              return self::hexToQuad( $hex );
 316          }
 317      }
 318  
 319      /**
 320       * Converts a hexadecimal number to an IPv6 address in octet notation
 321       *
 322       * @param string $ip_hex Pure hex (no v6- prefix)
 323       * @return string (of format a:b:c:d:e:f:g:h)
 324       */
 325  	public static function hexToOctet( $ip_hex ) {
 326          // Pad hex to 32 chars (128 bits)
 327          $ip_hex = str_pad( strtoupper( $ip_hex ), 32, '0', STR_PAD_LEFT );
 328          // Separate into 8 words
 329          $ip_oct = substr( $ip_hex, 0, 4 );
 330          for ( $n = 1; $n < 8; $n++ ) {
 331              $ip_oct .= ':' . substr( $ip_hex, 4 * $n, 4 );
 332          }
 333          // NO leading zeroes
 334          $ip_oct = preg_replace( '/(^|:)0+(' . RE_IPV6_WORD . ')/', '$1$2', $ip_oct );
 335  
 336          return $ip_oct;
 337      }
 338  
 339      /**
 340       * Converts a hexadecimal number to an IPv4 address in quad-dotted notation
 341       *
 342       * @param string $ip_hex Pure hex
 343       * @return string (of format a.b.c.d)
 344       */
 345  	public static function hexToQuad( $ip_hex ) {
 346          // Pad hex to 8 chars (32 bits)
 347          $ip_hex = str_pad( strtoupper( $ip_hex ), 8, '0', STR_PAD_LEFT );
 348          // Separate into four quads
 349          $s = '';
 350          for ( $i = 0; $i < 4; $i++ ) {
 351              if ( $s !== '' ) {
 352                  $s .= '.';
 353              }
 354              $s .= base_convert( substr( $ip_hex, $i * 2, 2 ), 16, 10 );
 355          }
 356  
 357          return $s;
 358      }
 359  
 360      /**
 361       * Determine if an IP address really is an IP address, and if it is public,
 362       * i.e. not RFC 1918 or similar
 363       *
 364       * @param string $ip
 365       * @return bool
 366       */
 367  	public static function isPublic( $ip ) {
 368          static $privateSet = null;
 369          if ( !$privateSet ) {
 370              $privateSet = new IPSet( array(
 371                  '10.0.0.0/8', # RFC 1918 (private)
 372                  '172.16.0.0/12', # RFC 1918 (private)
 373                  '192.168.0.0/16', # RFC 1918 (private)
 374                  '0.0.0.0/8', # this network
 375                  '127.0.0.0/8', # loopback
 376                  'fc00::/7', # RFC 4193 (local)
 377                  '0:0:0:0:0:0:0:1', # loopback
 378              ) );
 379          }
 380          return !$privateSet->match( $ip );
 381      }
 382  
 383      /**
 384       * Return a zero-padded upper case hexadecimal representation of an IP address.
 385       *
 386       * Hexadecimal addresses are used because they can easily be extended to
 387       * IPv6 support. To separate the ranges, the return value from this
 388       * function for an IPv6 address will be prefixed with "v6-", a non-
 389       * hexadecimal string which sorts after the IPv4 addresses.
 390       *
 391       * @param string $ip Quad dotted/octet IP address.
 392       * @return string|bool False on failure
 393       */
 394  	public static function toHex( $ip ) {
 395          if ( self::isIPv6( $ip ) ) {
 396              $n = 'v6-' . self::IPv6ToRawHex( $ip );
 397          } elseif ( self::isIPv4( $ip ) ) {
 398              // Bug 60035: an IP with leading 0's fails in ip2long sometimes (e.g. *.08)
 399              $ip = preg_replace( '/(?<=\.)0+(?=[1-9])/', '', $ip );
 400              $n = ip2long( $ip );
 401              if ( $n < 0 ) {
 402                  $n += pow( 2, 32 );
 403                  # On 32-bit platforms (and on Windows), 2^32 does not fit into an int,
 404                  # so $n becomes a float. We convert it to string instead.
 405                  if ( is_float( $n ) ) {
 406                      $n = (string)$n;
 407                  }
 408              }
 409              if ( $n !== false ) {
 410                  # Floating points can handle the conversion; faster than wfBaseConvert()
 411                  $n = strtoupper( str_pad( base_convert( $n, 10, 16 ), 8, '0', STR_PAD_LEFT ) );
 412              }
 413          } else {
 414              $n = false;
 415          }
 416  
 417          return $n;
 418      }
 419  
 420      /**
 421       * Given an IPv6 address in octet notation, returns a pure hex string.
 422       *
 423       * @param string $ip Octet ipv6 IP address.
 424       * @return string|bool Pure hex (uppercase); false on failure
 425       */
 426  	private static function IPv6ToRawHex( $ip ) {
 427          $ip = self::sanitizeIP( $ip );
 428          if ( !$ip ) {
 429              return false;
 430          }
 431          $r_ip = '';
 432          foreach ( explode( ':', $ip ) as $v ) {
 433              $r_ip .= str_pad( $v, 4, 0, STR_PAD_LEFT );
 434          }
 435  
 436          return $r_ip;
 437      }
 438  
 439      /**
 440       * Convert a network specification in CIDR notation
 441       * to an integer network and a number of bits
 442       *
 443       * @param string $range IP with CIDR prefix
 444       * @return array(int or string, int)
 445       */
 446  	public static function parseCIDR( $range ) {
 447          if ( self::isIPv6( $range ) ) {
 448              return self::parseCIDR6( $range );
 449          }
 450          $parts = explode( '/', $range, 2 );
 451          if ( count( $parts ) != 2 ) {
 452              return array( false, false );
 453          }
 454          list( $network, $bits ) = $parts;
 455          $network = ip2long( $network );
 456          if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 32 ) {
 457              if ( $bits == 0 ) {
 458                  $network = 0;
 459              } else {
 460                  $network &= ~( ( 1 << ( 32 - $bits ) ) - 1 );
 461              }
 462              # Convert to unsigned
 463              if ( $network < 0 ) {
 464                  $network += pow( 2, 32 );
 465              }
 466          } else {
 467              $network = false;
 468              $bits = false;
 469          }
 470  
 471          return array( $network, $bits );
 472      }
 473  
 474      /**
 475       * Given a string range in a number of formats,
 476       * return the start and end of the range in hexadecimal.
 477       *
 478       * Formats are:
 479       *     1.2.3.4/24          CIDR
 480       *     1.2.3.4 - 1.2.3.5   Explicit range
 481       *     1.2.3.4             Single IP
 482       *
 483       *     2001:0db8:85a3::7344/96                       CIDR
 484       *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 485       *     2001:0db8:85a3::7344                          Single IP
 486       * @param string $range IP range
 487       * @return array(string, string)
 488       */
 489  	public static function parseRange( $range ) {
 490          // CIDR notation
 491          if ( strpos( $range, '/' ) !== false ) {
 492              if ( self::isIPv6( $range ) ) {
 493                  return self::parseRange6( $range );
 494              }
 495              list( $network, $bits ) = self::parseCIDR( $range );
 496              if ( $network === false ) {
 497                  $start = $end = false;
 498              } else {
 499                  $start = sprintf( '%08X', $network );
 500                  $end = sprintf( '%08X', $network + pow( 2, ( 32 - $bits ) ) - 1 );
 501              }
 502          // Explicit range
 503          } elseif ( strpos( $range, '-' ) !== false ) {
 504              list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 505              if ( self::isIPv6( $start ) && self::isIPv6( $end ) ) {
 506                  return self::parseRange6( $range );
 507              }
 508              if ( self::isIPv4( $start ) && self::isIPv4( $end ) ) {
 509                  $start = self::toHex( $start );
 510                  $end = self::toHex( $end );
 511                  if ( $start > $end ) {
 512                      $start = $end = false;
 513                  }
 514              } else {
 515                  $start = $end = false;
 516              }
 517          } else {
 518              # Single IP
 519              $start = $end = self::toHex( $range );
 520          }
 521          if ( $start === false || $end === false ) {
 522              return array( false, false );
 523          } else {
 524              return array( $start, $end );
 525          }
 526      }
 527  
 528      /**
 529       * Convert a network specification in IPv6 CIDR notation to an
 530       * integer network and a number of bits
 531       *
 532       * @param string $range
 533       *
 534       * @return array(string, int)
 535       */
 536  	private static function parseCIDR6( $range ) {
 537          # Explode into <expanded IP,range>
 538          $parts = explode( '/', IP::sanitizeIP( $range ), 2 );
 539          if ( count( $parts ) != 2 ) {
 540              return array( false, false );
 541          }
 542          list( $network, $bits ) = $parts;
 543          $network = self::IPv6ToRawHex( $network );
 544          if ( $network !== false && is_numeric( $bits ) && $bits >= 0 && $bits <= 128 ) {
 545              if ( $bits == 0 ) {
 546                  $network = "0";
 547              } else {
 548                  # Native 32 bit functions WONT work here!!!
 549                  # Convert to a padded binary number
 550                  $network = wfBaseConvert( $network, 16, 2, 128 );
 551                  # Truncate the last (128-$bits) bits and replace them with zeros
 552                  $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
 553                  # Convert back to an integer
 554                  $network = wfBaseConvert( $network, 2, 10 );
 555              }
 556          } else {
 557              $network = false;
 558              $bits = false;
 559          }
 560  
 561          return array( $network, (int)$bits );
 562      }
 563  
 564      /**
 565       * Given a string range in a number of formats, return the
 566       * start and end of the range in hexadecimal. For IPv6.
 567       *
 568       * Formats are:
 569       *     2001:0db8:85a3::7344/96                       CIDR
 570       *     2001:0db8:85a3::7344 - 2001:0db8:85a3::7344   Explicit range
 571       *     2001:0db8:85a3::7344/96                       Single IP
 572       *
 573       * @param string $range
 574       *
 575       * @return array(string, string)
 576       */
 577  	private static function parseRange6( $range ) {
 578          # Expand any IPv6 IP
 579          $range = IP::sanitizeIP( $range );
 580          // CIDR notation...
 581          if ( strpos( $range, '/' ) !== false ) {
 582              list( $network, $bits ) = self::parseCIDR6( $range );
 583              if ( $network === false ) {
 584                  $start = $end = false;
 585              } else {
 586                  $start = wfBaseConvert( $network, 10, 16, 32, false );
 587                  # Turn network to binary (again)
 588                  $end = wfBaseConvert( $network, 10, 2, 128 );
 589                  # Truncate the last (128-$bits) bits and replace them with ones
 590                  $end = str_pad( substr( $end, 0, $bits ), 128, 1, STR_PAD_RIGHT );
 591                  # Convert to hex
 592                  $end = wfBaseConvert( $end, 2, 16, 32, false );
 593                  # see toHex() comment
 594                  $start = "v6-$start";
 595                  $end = "v6-$end";
 596              }
 597          // Explicit range notation...
 598          } elseif ( strpos( $range, '-' ) !== false ) {
 599              list( $start, $end ) = array_map( 'trim', explode( '-', $range, 2 ) );
 600              $start = self::toHex( $start );
 601              $end = self::toHex( $end );
 602              if ( $start > $end ) {
 603                  $start = $end = false;
 604              }
 605          } else {
 606              # Single IP
 607              $start = $end = self::toHex( $range );
 608          }
 609          if ( $start === false || $end === false ) {
 610              return array( false, false );
 611          } else {
 612              return array( $start, $end );
 613          }
 614      }
 615  
 616      /**
 617       * Determine if a given IPv4/IPv6 address is in a given CIDR network
 618       *
 619       * @param string $addr The address to check against the given range.
 620       * @param string $range The range to check the given address against.
 621       * @return bool Whether or not the given address is in the given range.
 622       */
 623  	public static function isInRange( $addr, $range ) {
 624          $hexIP = self::toHex( $addr );
 625          list( $start, $end ) = self::parseRange( $range );
 626  
 627          return ( strcmp( $hexIP, $start ) >= 0 &&
 628              strcmp( $hexIP, $end ) <= 0 );
 629      }
 630  
 631      /**
 632       * Convert some unusual representations of IPv4 addresses to their
 633       * canonical dotted quad representation.
 634       *
 635       * This currently only checks a few IPV4-to-IPv6 related cases.  More
 636       * unusual representations may be added later.
 637       *
 638       * @param string $addr Something that might be an IP address
 639       * @return string Valid dotted quad IPv4 address or null
 640       */
 641  	public static function canonicalize( $addr ) {
 642          // remove zone info (bug 35738)
 643          $addr = preg_replace( '/\%.*/', '', $addr );
 644  
 645          if ( self::isValid( $addr ) ) {
 646              return $addr;
 647          }
 648          // Turn mapped addresses from ::ce:ffff:1.2.3.4 to 1.2.3.4
 649          if ( strpos( $addr, ':' ) !== false && strpos( $addr, '.' ) !== false ) {
 650              $addr = substr( $addr, strrpos( $addr, ':' ) + 1 );
 651              if ( self::isIPv4( $addr ) ) {
 652                  return $addr;
 653              }
 654          }
 655          // IPv6 loopback address
 656          $m = array();
 657          if ( preg_match( '/^0*' . RE_IPV6_GAP . '1$/', $addr, $m ) ) {
 658              return '127.0.0.1';
 659          }
 660          // IPv4-mapped and IPv4-compatible IPv6 addresses
 661          if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . '(' . RE_IP_ADD . ')$/i', $addr, $m ) ) {
 662              return $m[1];
 663          }
 664          if ( preg_match( '/^' . RE_IPV6_V4_PREFIX . RE_IPV6_WORD .
 665              ':' . RE_IPV6_WORD . '$/i', $addr, $m )
 666          ) {
 667              return long2ip( ( hexdec( $m[1] ) << 16 ) + hexdec( $m[2] ) );
 668          }
 669  
 670          return null; // give up
 671      }
 672  
 673      /**
 674       * Gets rid of unneeded numbers in quad-dotted/octet IP strings
 675       * For example, 127.111.113.151/24 -> 127.111.113.0/24
 676       * @param string $range IP address to normalize
 677       * @return string
 678       */
 679  	public static function sanitizeRange( $range ) {
 680          list( /*...*/, $bits ) = self::parseCIDR( $range );
 681          list( $start, /*...*/ ) = self::parseRange( $range );
 682          $start = self::formatHex( $start );
 683          if ( $bits === false ) {
 684              return $start; // wasn't actually a range
 685          }
 686  
 687          return "$start/$bits";
 688      }
 689  
 690      /**
 691       * Checks if an IP is a trusted proxy provider.
 692       * Useful to tell if X-Forwarded-For data is possibly bogus.
 693       * Squid cache servers for the site are whitelisted.
 694       * @since 1.24
 695       *
 696       * @param string $ip
 697       * @return bool
 698       */
 699  	public static function isTrustedProxy( $ip ) {
 700          $trusted = self::isConfiguredProxy( $ip );
 701          wfRunHooks( 'IsTrustedProxy', array( &$ip, &$trusted ) );
 702          return $trusted;
 703      }
 704  
 705      /**
 706       * Checks if an IP matches a proxy we've configured
 707       * @since 1.24
 708       *
 709       * @param string $ip
 710       * @return bool
 711       */
 712  	public static function isConfiguredProxy( $ip ) {
 713          global $wgSquidServers, $wgSquidServersNoPurge;
 714  
 715          wfProfileIn( __METHOD__ );
 716          // Quick check of known singular proxy servers
 717          $trusted = in_array( $ip, $wgSquidServers );
 718  
 719          // Check against addresses and CIDR nets in the NoPurge list
 720          if ( !$trusted ) {
 721              if ( !self::$proxyIpSet ) {
 722                  self::$proxyIpSet = new IPSet( $wgSquidServersNoPurge );
 723              }
 724              $trusted = self::$proxyIpSet->match( $ip );
 725          }
 726          wfProfileOut( __METHOD__ );
 727  
 728          return $trusted;
 729      }
 730  
 731      /**
 732       * Clears precomputed data used for proxy support.
 733       * Use this only for unit tests.
 734       */
 735  	public static function clearCaches() {
 736          self::$proxyIpSet = null;
 737      }
 738  }