tear ipv6

cidripv6.php

<?php 

$ip = '2001:0df0:021f:0000:0000:0000:0000:0000';
$cidrnet = '2001:df0:21f::/48';

function inet_to_bits($inet) 
{
   $splitted = str_split($inet);
   $binaryip = '';
   foreach ($splitted as $char) {
             $binaryip .= str_pad(decbin(ord($char)), 8, '0', STR_PAD_LEFT);
   }
   return $binaryip;
}    

$ip = inet_pton($ip);
$binaryip=inet_to_bits($ip);

list($net,$maskbits)=explode('/',$cidrnet);
$net=inet_pton($net);
$binarynet=inet_to_bits($net);

$ip_net_bits=substr($binaryip,0,$maskbits);
$net_bits   =substr($binarynet,0,$maskbits);

if($ip_net_bits!==$net_bits) echo 'Not in subnet';
else echo 'In subnet';

// source https://stackoverflow.com/questions/7951061/matching-ipv6-address-to-a-cidr-subnet
?>