<?php
function convertIPv6To4($ip) {
// validate if given IP is a proper IPv6 address
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {
// validate if given IP is a proper IPv4 address
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) === false) {
// ip address is invalid
return '';
}
return $ip;
}
// check if ip is a masked IPv4 address
if (substr($ip, 0, 7) == '::ffff:') {
$ip = substr($ip, 7);
if (preg_match('~^([a-f0-9]{1,4}):([a-f0-9]{1,4})$~', $ip, $matches)) {
$ip = array(
base_convert($matches[1], 16, 10),
base_convert($matches[2], 16, 10)
);
$ipParts = array();
$tmp = $ip[0] % 256;
$ipParts[] = ($ip[0] - $tmp) / 256;
$ipParts[] = $tmp;
$tmp = $ip[1] % 256;
$ipParts[] = ($ip[1] - $tmp) / 256;
$ipParts[] = $tmp;
return implode('.', $ipParts);
}
else {
return $ip;
}
}
else {
// given ip is an IPv6 address and cannot be converted
return $ip;
}
}
echo convertIPv6To4('2003:66:4f14:d880:7075:9457:3857:29ec')
?>
preferences:
26.53 ms | 402 KiB | 5 Q