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   1  <?php
   2  /**
   3   * Class to validate and to work with IPv6 addresses
   4   *
   5   * @package Requests\Utilities
   6   */
   7  
   8  namespace WpOrg\Requests;
   9  
  10  use WpOrg\Requests\Exception\InvalidArgument;
  11  use WpOrg\Requests\Utility\InputValidator;
  12  
  13  /**
  14   * Class to validate and to work with IPv6 addresses
  15   *
  16   * This was originally based on the PEAR class of the same name, but has been
  17   * entirely rewritten.
  18   *
  19   * @package Requests\Utilities
  20   */
  21  final class Ipv6 {
  22      /**
  23       * Uncompresses an IPv6 address
  24       *
  25       * RFC 4291 allows you to compress consecutive zero pieces in an address to
  26       * '::'. This method expects a valid IPv6 address and expands the '::' to
  27       * the required number of zero pieces.
  28       *
  29       * Example:  FF01::101   ->  FF01:0:0:0:0:0:0:101
  30       *           ::1         ->  0:0:0:0:0:0:0:1
  31       *
  32       * @author Alexander Merz <alexander.merz@web.de>
  33       * @author elfrink at introweb dot nl
  34       * @author Josh Peck <jmp at joshpeck dot org>
  35       * @copyright 2003-2005 The PHP Group
  36       * @license https://opensource.org/licenses/bsd-license.php
  37       *
  38       * @param string|Stringable $ip An IPv6 address
  39       * @return string The uncompressed IPv6 address
  40       *
  41       * @throws \WpOrg\Requests\Exception\InvalidArgument When the passed argument is not a string or a stringable object.
  42       */
  43  	public static function uncompress($ip) {
  44          if (InputValidator::is_string_or_stringable($ip) === false) {
  45              throw InvalidArgument::create(1, '$ip', 'string|Stringable', gettype($ip));
  46          }
  47  
  48          $ip = (string) $ip;
  49  
  50          if (substr_count($ip, '::') !== 1) {
  51              return $ip;
  52          }
  53  
  54          list($ip1, $ip2) = explode('::', $ip);
  55          $c1              = ($ip1 === '') ? -1 : substr_count($ip1, ':');
  56          $c2              = ($ip2 === '') ? -1 : substr_count($ip2, ':');
  57  
  58          if (strpos($ip2, '.') !== false) {
  59              $c2++;
  60          }
  61  
  62          if ($c1 === -1 && $c2 === -1) {
  63              // ::
  64              $ip = '0:0:0:0:0:0:0:0';
  65          } elseif ($c1 === -1) {
  66              // ::xxx
  67              $fill = str_repeat('0:', 7 - $c2);
  68              $ip   = str_replace('::', $fill, $ip);
  69          } elseif ($c2 === -1) {
  70              // xxx::
  71              $fill = str_repeat(':0', 7 - $c1);
  72              $ip   = str_replace('::', $fill, $ip);
  73          } else {
  74              // xxx::xxx
  75              $fill = ':' . str_repeat('0:', 6 - $c2 - $c1);
  76              $ip   = str_replace('::', $fill, $ip);
  77          }
  78  
  79          return $ip;
  80      }
  81  
  82      /**
  83       * Compresses an IPv6 address
  84       *
  85       * RFC 4291 allows you to compress consecutive zero pieces in an address to
  86       * '::'. This method expects a valid IPv6 address and compresses consecutive
  87       * zero pieces to '::'.
  88       *
  89       * Example:  FF01:0:0:0:0:0:0:101   ->  FF01::101
  90       *           0:0:0:0:0:0:0:1        ->  ::1
  91       *
  92       * @see \WpOrg\Requests\Ipv6::uncompress()
  93       *
  94       * @param string $ip An IPv6 address
  95       * @return string The compressed IPv6 address
  96       */
  97  	public static function compress($ip) {
  98          // Prepare the IP to be compressed.
  99          // Note: Input validation is handled in the `uncompress()` method, which is the first call made in this method.
 100          $ip       = self::uncompress($ip);
 101          $ip_parts = self::split_v6_v4($ip);
 102  
 103          // Replace all leading zeros
 104          $ip_parts[0] = preg_replace('/(^|:)0+([0-9])/', '\1\2', $ip_parts[0]);
 105  
 106          // Find bunches of zeros
 107          if (preg_match_all('/(?:^|:)(?:0(?::|$))+/', $ip_parts[0], $matches, PREG_OFFSET_CAPTURE)) {
 108              $max = 0;
 109              $pos = null;
 110              foreach ($matches[0] as $match) {
 111                  if (strlen($match[0]) > $max) {
 112                      $max = strlen($match[0]);
 113                      $pos = $match[1];
 114                  }
 115              }
 116  
 117              $ip_parts[0] = substr_replace($ip_parts[0], '::', $pos, $max);
 118          }
 119  
 120          if ($ip_parts[1] !== '') {
 121              return implode(':', $ip_parts);
 122          } else {
 123              return $ip_parts[0];
 124          }
 125      }
 126  
 127      /**
 128       * Splits an IPv6 address into the IPv6 and IPv4 representation parts
 129       *
 130       * RFC 4291 allows you to represent the last two parts of an IPv6 address
 131       * using the standard IPv4 representation
 132       *
 133       * Example:  0:0:0:0:0:0:13.1.68.3
 134       *           0:0:0:0:0:FFFF:129.144.52.38
 135       *
 136       * @param string $ip An IPv6 address
 137       * @return string[] [0] contains the IPv6 represented part, and [1] the IPv4 represented part
 138       */
 139  	private static function split_v6_v4($ip) {
 140          if (strpos($ip, '.') !== false) {
 141              $pos       = strrpos($ip, ':');
 142              $ipv6_part = substr($ip, 0, $pos);
 143              $ipv4_part = substr($ip, $pos + 1);
 144              return [$ipv6_part, $ipv4_part];
 145          } else {
 146              return [$ip, ''];
 147          }
 148      }
 149  
 150      /**
 151       * Checks an IPv6 address
 152       *
 153       * Checks if the given IP is a valid IPv6 address
 154       *
 155       * @param string $ip An IPv6 address
 156       * @return bool true if $ip is a valid IPv6 address
 157       */
 158  	public static function check_ipv6($ip) {
 159          // Note: Input validation is handled in the `uncompress()` method, which is the first call made in this method.
 160          $ip                = self::uncompress($ip);
 161          list($ipv6, $ipv4) = self::split_v6_v4($ip);
 162          $ipv6              = explode(':', $ipv6);
 163          $ipv4              = explode('.', $ipv4);
 164          if (count($ipv6) === 8 && count($ipv4) === 1 || count($ipv6) === 6 && count($ipv4) === 4) {
 165              foreach ($ipv6 as $ipv6_part) {
 166                  // The section can't be empty
 167                  if ($ipv6_part === '') {
 168                      return false;
 169                  }
 170  
 171                  // Nor can it be over four characters
 172                  if (strlen($ipv6_part) > 4) {
 173                      return false;
 174                  }
 175  
 176                  // Remove leading zeros (this is safe because of the above)
 177                  $ipv6_part = ltrim($ipv6_part, '0');
 178                  if ($ipv6_part === '') {
 179                      $ipv6_part = '0';
 180                  }
 181  
 182                  // Check the value is valid
 183                  $value = hexdec($ipv6_part);
 184                  if (dechex($value) !== strtolower($ipv6_part) || $value < 0 || $value > 0xFFFF) {
 185                      return false;
 186                  }
 187              }
 188  
 189              if (count($ipv4) === 4) {
 190                  foreach ($ipv4 as $ipv4_part) {
 191                      $value = (int) $ipv4_part;
 192                      if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF) {
 193                          return false;
 194                      }
 195                  }
 196              }
 197  
 198              return true;
 199          } else {
 200              return false;
 201          }
 202      }
 203  }