/**
* Convert an IPv4 address into an IPv6 address.
*
* One use-case for this is IP 6to4 tunnels used in networking.
*
* @example
* to_ipv6("10.10.10.10") == a0a:a0a
*
* @param string $ip IPv4 address.
* @param boolean $mapped If true a Full IPv6 address is returned within the
* official ipv4to6 mapped space "0:0:0:0:0:ffff:x:x"
*/
public static function to_ipv6($ip, $mapped = false)
{
if (!self::isIPv4($ip)) {
throw new \InvalidArgumentException("Invalid IPv4 address \"{$ip}\"");
}
$num = IP::inet_ptod($ip);
$o1 = dechex($num >> 16);
$o2 = dechex($num & 0xffff);
return $mapped ? "0:0:0:0:0:ffff:{$o1}:{$o2}" : "{$o1}:{$o2}";
}
/**
* Return the network mask for the prefix given.
*
* Normally this is only useful for IPv4 addresses but you can generate a
* mask for IPv6 addresses as well, only because its mathematically
* possible.
*
* @param integer $prefix CIDR prefix bits (0-128)
* @param integer $version IP version. If null the version will be detected
* based on the prefix length given.
*/
public static function prefix_to_mask($prefix, $version = null)
{
if ($version === null) {
$version = $prefix > 32 ? 6 : 4;
}
if ($prefix < 0 or $prefix > 128) {
throw new \InvalidArgumentException("Invalid prefix length \"{$prefix}\"");
}
if ($version != 4 and $version != 6) {
throw new \InvalidArgumentException("Invalid version \"{$version}\". Must be 4 or 6");
}
if ($version == 4) {
return long2ip($prefix == 0 ? 0 : 0xffffffff >> 32 - $prefix << 32 - $prefix);
} else {
return IP::inet_dtop($prefix == 0 ? 0 : BC::bcleft(BC::bcright(BC::MAX_UINT_128, 128 - $prefix), 128 - $prefix));
}
}
