Getting list IPs from CIDR notation in PHP

Question

Is there a way (or function/class) to get the list of IP addresses from a CIDR notation?

For example, I have 73.35.143.32/27 CIDR and want to get the list of all IP\

Answer 1

I had some problems with the previous versions, various PHP errors like undefined offset etc.

I found what I think is a better way to do it without the errors as detailed below.

This takes IPV4 CIDR notation IP addresses and can be used to get the start/end IP addresses of the CIDR range or count the total number of IP addresses in a database of IP addresses.

    $count = 0;
    $result = $sia_db_con->query("SELECT `ip_address` FROM `ip4` WHERE `ip_ban_active`='True' ORDER BY ip4.added ASC");
while ($row = $result->fetch_array()) {
    $pos = strpos($row[0], "/");
    $ip_arr = [0 => substr($row[0], 0, $pos), 1 => substr($row[0], $pos+1)];
    $start = cidr2ip($ip_arr)[0];
    $end = cidr2ip($ip_arr)[1];
    $count = $count + (ip2long($end) - ip2long($start)) + 1;
}
    unset($result, $row, $pos, $ip_arr, $start, $end, $range);

function cidr2ip($cidr) {
    $start = ip2long($cidr[0]);
    $nm = $cidr[1];
    $num = pow(2, 32 - $nm);
    $end = $start + $num - 1;
    $range = [0 => $cidr[0], 1 => long2ip($end)];
    unset($start, $nm, $num, $end);
    return $range;
}

The secret here is the way in which I create the $ip_arr variable. Rather than using PHP explode, I set the array dimensions manually for each IP address. This is of course a database version of the code and cycles through all IP addresses in the database which meet the search criteria.