How to matching an IP to a CIDR mask in PHP 5

0 votes

I'm looking for quick/simple method for matching a given IP4 dotted quad IP to a CIDR notation mask.

I have a bunch of IPs I need to see if they match a range of IPs.

example:

$ips = array('10.2.1.100', '10.2.1.101', '10.5.1.100', '1.2.3.4');

foreach ($ips as $IP) {
    if (cidr_match($IP, '10.2.0.0/16') == true) {
        print "you're in the 10.2 subnet\n"; 
    }
}

What would cidr_match() look like?

It doesn't really have to be simple, but fast would be good. Anything that uses only built-in/common functions is a bonus (as I'm likely to get one person to show me something in pear that does this, but I can't depend on pear or that package being installed where my code is deployed).

Nov 6, 2020 in PHP by kartik
• 37,510 points
2,762 views

1 answer to this question.

0 votes

Hello @kartik,

If only using IPv4:

  • use ip2long() to convert the IPs and the subnet range into long integers
  • convert the /xx into a subnet mask
  • do a bitwise 'and' (i.e. ip & mask)' and check that that 'result = subnet'

something like this should work:

function cidr_match($ip, $range)
{
    list ($subnet, $bits) = explode('/', $range);
    if ($bits === null) {
        $bits = 32;
    }
    $ip = ip2long($ip);
    $subnet = ip2long($subnet);
    $mask = -1 << (32 - $bits);
    $subnet &= $mask; # nb: in case the supplied subnet wasn't correctly aligned
    return ($ip & $mask) == $subnet;
}

Hope it helps!! 

answered Nov 6, 2020 by Niroj
• 82,880 points

Related Questions In PHP

0 votes
0 answers

How to convert an array to a string in PHP?

What can I do to get the ...READ MORE

May 30, 2022 in PHP by Kichu
• 19,050 points
395 views
0 votes
0 answers

How to convert a string to an array in php

I want to convert a string into ...READ MORE

Jun 1, 2022 in PHP by Kichu
• 19,050 points
240 views
0 votes
0 answers

How to sort an array of associative arrays by value of a given key in PHP?

Given this array: $inventory = array( ...READ MORE

Jul 24, 2022 in PHP by Kithuzzz
• 38,010 points
408 views
0 votes
1 answer

How to get the client IP address in PHP ?

Hello, Here is a code sample of a good ...READ MORE

answered Apr 8, 2020 in PHP by Niroj
• 82,880 points
6,482 views
+1 vote
1 answer

How to make anchor tag with routing using Laravel?

Hey @kartik, First you have to go to ...READ MORE

answered Mar 18, 2020 in Laravel by Niroj
• 82,880 points
21,755 views
0 votes
1 answer

What is redirection in Laravel?

Named route is used to give specific ...READ MORE

answered Mar 18, 2020 in Laravel by Niroj
• 82,880 points
2,647 views
0 votes
1 answer

How to install Laravel via composer?

Hello, This is simple you just need to ...READ MORE

answered Mar 23, 2020 in Laravel by Niroj
• 82,880 points
2,506 views
+1 vote
1 answer

What are named routes in Laravel and How can specify route names for controller actions?

Hey @kartik, Named routing is another amazing feature of ...READ MORE

answered Mar 23, 2020 in Laravel by Niroj
• 82,880 points
41,378 views
0 votes
1 answer

How to check an IP address is within a range of two IPs in PHP?

Hello @kartik, With ip2long() it's easy to convert your addresses ...READ MORE

answered Nov 3, 2020 in PHP by Niroj
• 82,880 points
3,166 views
0 votes
1 answer

How to check if a string is an email address in PHP?

Hello, Try this without regular expressions: <?php ...READ MORE

answered Nov 3, 2020 in PHP by Niroj
• 82,880 points
3,118 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP