<?php

function ipVersion($ip)
{
    return strpos($ip, ":") === false ? 4 : 6;
}

function inRange($ip, $ranges)
{
    $ranges = (array)$ranges;
    $addressLength = ipVersion($ip) == 4 ? 32 : 128;
    foreach ($ranges as $range) {
        list($address, $cidr) = explode('/', $range);
        if ((bindec(ip2bin($ip)) & ~((1 << ($addressLength - $cidr)) - 1)) == bindec(ip2bin($address))) {
            return true;
        }
    }
    return false;
}

/**
* Converts IP address to bits representation
*
* @param $ip string
* @return string string of bits
*/
function ip2bin($ip)
{
    if (ipVersion($ip) == 4) {
        return str_pad(base_convert(ip2long($ip), 10, 2), 32, '0', STR_PAD_LEFT);
    } else {
        $unpack = unpack("A16", inet_pton($ip));
        $binStr = array_shift($unpack);
        $bits = 16; // 16*8 bit = 128 bit (IPv6)
        $result = '';
        while ($bits-- > 0) {
            $result = sprintf("%08b", isset($binStr[$bits]) ? ord($binStr[$bits]) : '0') . $result;
        }
        return $result;
    }
}

echo "\n2001:ab::1 as BIN(str): ";
var_dump(ip2bin('2001:ab::1'));
echo "same as DEC: ";
var_dump(bindec(ip2bin('2001:ab::1')));

echo "\n\nIPv4 10.0.1.5: ";
var_dump(ip2bin('10.0.1.5'));
echo "same as DEC: ";
var_dump(bindec(ip2bin('10.0.1.5')));

echo "\n\nAnd here is an IPv4 mask /30:";
var_dump(decbin(~(1 << (32 - 30)) - 1));

echo "\n\nBut unable to create a bit mask grater than int(32). For example /64:";
var_dump(decbin(~(1 << (128-64)) - 1));