Matching an IP to a CIDR mask in PHP 5?

php cidr

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).


Solution 1:

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;
}

Solution 2:

In a similar situation, I ended up using symfony/http-foundation.

When using this package, your code would look like:

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

foreach($ips as $IP) {
    if (\Symfony\Component\HttpFoundation\IpUtils::checkIp($IP, '10.2.0.0/16')) {
        print "you're in the 10.2 subnet\n";
    }
}

It also handles IPv6.

Link: https://packagist.org/packages/symfony/http-foundation

Solution 3:

I found many of these methods breaking after PHP 5.2. However the following solution works on versions 5.2 and above:

function cidr_match($ip, $cidr)
{
    list($subnet, $mask) = explode('/', $cidr);

    if ((ip2long($ip) & ~((1 << (32 - $mask)) - 1) ) == ip2long($subnet))
    { 
        return true;
    }

    return false;
}

Example results

cidr_match("1.2.3.4", "0.0.0.0/0"):         true
cidr_match("127.0.0.1", "127.0.0.1/32"):    true
cidr_match("127.0.0.1", "127.0.0.2/32"):    false

Source http://www.php.net/manual/en/function.ip2long.php#82397.

Solution 4:

Some function changed:

  • split with explode
function cidr_match($ip, $range)
{
    list ($subnet, $bits) = explode('/', $range);
    $ip = ip2long($ip);
    $subnet = ip2long($subnet);
    $mask = -1 << (32 - $bits);
    $subnet &= $mask; 
    return ($ip & $mask) == $subnet;
}

Solution 5:

Here is one fast 64bits function to do it, please comment the return line you don't need. Accepting any valid Ipv4 with or without valid CIDR Routing Prefix for example 63.161.156.0/24 or 63.161.156.0

<?php
function cidr2range($ipv4){
if ($ip=strpos($ipv4,'/'))
{$n_ip=(1<<(32-substr($ipv4,1+$ip)))-1;   $ip_dec=ip2long(substr($ipv4,0,$ip)); }
else
{$n_ip=0;                                   $ip_dec=ip2long($ipv4);             }
$ip_min=$ip_dec&~$n_ip;
$ip_max=$ip_min+$n_ip;
#Array(2) of Decimal Values Range
return [$ip_min,$ip_max];
#Array(2) of Ipv4 Human Readable Range
return [long2ip($ip_min),long2ip($ip_max)];
#Array(2) of Ipv4 and Subnet Range
return [long2ip($ip_min),long2ip(~$n_ip)];
#Array(2) of Ipv4 and Wildcard Bits
return [long2ip($ip_min),long2ip($n_ip)];
#Integer Number of Ipv4 in Range
return ++$n_ip;
}

To fast check if a given ipv4 is matching a given CIDR you can do it inline like in this example

<?php
$given_cidr='55.55.55.0/24';
$given_ipv4='55.55.55.55';
if(($range=cidr2range($given_cidr)) &&
($check=ip2long($given_ipv4))!==false &&
$check>=$range[0] && $check<=$range[1])
{
echo 'Yes, '.$given_ipv4.' is included in '.$given_cidr;
}
else
{
echo 'No, '.$given_ipv4.' is not included in '.$given_cidr;
}

To get the full range as an array for a given IP (with or without CIDR Routing Prefix) you can use the following code but be carefull because for example 25.25.25.25/16 return an array with 65536 elements and you can easily run out of memory using a smaller Routing Prefix

<?php
$result=cidr2range($ipv4);
for($ip_dec=$result[0];$ip_dec<=$result[1];$ip_dec++)
$full_range[$ip_dec]=long2ip($ip_dec);
print_r($full_range);

To fast check if a given ipv4 is matching a given array of IP (with or without CIDR Routing Prefix)

<?php
#This code is checking if a given ip belongs to googlebot
$given_ipv4='74.125.61.208';
$given_cidr_array=['108.59.93.43/32','108.59.93.40/31','108.59.93.44/30','108.59.93.32/29','108.59.93.48/28','108.59.93.0/27','108.59.93.64/26','108.59.93.192/26','108.59.92.192/27','108.59.92.128/26','108.59.92.96/27','108.59.92.0/27','108.59.94.208/29','108.59.94.192/28','108.59.94.240/28','108.59.94.128/26','108.59.94.16/29','108.59.94.0/28','108.59.94.32/27','108.59.94.64/26','108.59.95.0/24','108.59.88.0/22','108.59.81.0/27','108.59.80.0/24','108.59.82.0/23','108.59.84.0/22','108.170.217.128/28','108.170.217.160/27','108.170.217.192/26','108.170.217.0/25','108.170.216.0/24','108.170.218.0/23','108.170.220.0/22','108.170.208.0/21','108.170.192.0/20','108.170.224.0/19','108.177.0.0/17','104.132.0.0/14','104.154.0.0/15','104.196.0.0/14','107.167.160.0/19','107.178.192.0/18','125.17.82.112/30','125.16.7.72/30','74.125.0.0/16','72.14.192.0/18','77.109.131.208/28','77.67.50.32/27','66.102.0.0/20','66.227.77.144/29','66.249.64.0/19','67.148.177.136/29','64.124.98.104/29','64.71.148.240/29','64.68.64.64/26','64.68.80.0/20','64.41.221.192/28','64.41.146.208/28','64.9.224.0/19','64.233.160.0/19','65.171.1.144/28','65.170.13.0/28','65.167.144.64/28','65.220.13.0/24','65.216.183.0/24','70.32.132.0/23','70.32.128.0/22','70.32.136.0/21','70.32.144.0/20','85.182.250.128/26','85.182.250.0/25','80.239.168.192/26','80.149.20.0/25','61.246.224.136/30','61.246.190.124/30','63.237.119.112/29','63.226.245.56/29','63.158.137.224/29','63.166.17.128/25','63.161.156.0/24','63.88.22.0/23','41.206.188.128/26','12.234.149.240/29','12.216.80.0/24','8.34.217.24/29','8.34.217.0/28','8.34.217.32/27','8.34.217.64/26','8.34.217.128/25','8.34.216.0/24','8.34.218.0/23','8.34.220.0/22','8.34.208.128/29','8.34.208.144/28','8.34.208.160/27','8.34.208.192/26','8.34.208.0/25','8.34.209.0/24','8.34.210.0/23','8.34.212.0/22','8.35.195.128/28','8.35.195.160/27','8.35.195.192/26','8.35.195.0/25','8.35.194.0/24','8.35.192.0/23','8.35.196.0/22','8.35.200.0/21','8.8.8.0/24','8.8.4.0/24','8.6.48.0/21','4.3.2.0/24','23.236.48.0/20','23.251.128.0/19','216.239.32.0/19','216.252.220.0/22','216.136.145.128/27','216.33.229.160/29','216.33.229.144/29','216.34.7.176/28','216.58.192.0/19','216.109.75.80/28','216.74.130.48/28','216.74.153.0/27','217.118.234.96/28','208.46.199.160/29','208.44.48.240/29','208.21.209.0/28','208.184.125.240/28','209.185.108.128/25','209.85.128.0/17','213.200.103.128/26','213.200.99.192/26','213.155.151.128/26','199.192.112.224/29','199.192.112.192/27','199.192.112.128/26','199.192.112.0/25','199.192.113.176/28','199.192.113.128/27','199.192.113.192/26','199.192.113.0/25','199.192.115.80/28','199.192.115.96/27','199.192.115.0/28','199.192.115.128/25','199.192.114.192/26','199.192.114.0/25','199.223.232.0/21','198.108.100.192/28','195.16.45.144/29','192.104.160.0/23','192.158.28.0/22','192.178.0.0/15','206.160.135.240/28','207.223.160.0/20','203.222.167.144/28','173.255.125.72/29','173.255.125.80/28','173.255.125.96/27','173.255.125.0/27','173.255.125.128/25','173.255.124.240/29','173.255.124.232/29','173.255.124.192/27','173.255.124.128/29','173.255.124.144/28','173.255.124.160/27','173.255.124.48/29','173.255.124.32/28','173.255.124.0/27','173.255.124.64/26','173.255.126.0/23','173.255.122.128/26','173.255.122.64/26','173.255.123.0/24','173.255.121.128/26','173.255.121.0/25','173.255.120.0/24','173.255.117.32/27','173.255.117.64/26','173.255.117.128/25','173.255.116.192/27','173.255.116.128/26','173.255.116.0/25','173.255.118.0/23','173.255.112.0/22','173.194.0.0/16','172.102.8.0/21','172.253.0.0/16','172.217.0.0/16','162.216.148.0/22','162.222.176.0/21','180.87.33.64/26','128.177.109.0/26','128.177.119.128/25','128.177.163.0/25','130.211.0.0/16','142.250.0.0/15','146.148.0.0/17'];
echo '<pre>';
$in_range=false;
if (($given_ipv4_dec=ip2long($given_ipv4))!==false)
{
foreach($given_cidr_array as $given_cidr){
if(($range=cidr2range($given_cidr)) &&
$given_ipv4_dec>=$range[0] && $given_ipv4_dec<=$range[1])
{
$in_range=true;
echo $given_ipv4.' matched '.$given_cidr.' ('.join(array_map('long2ip',$range),' - ').")\n";
}
}
}
echo $given_ipv4.' is probably'.($in_range?'':' not').' a Googlebot IP';

To run fast the function don't check input but formally it should be a string matching the following regex

#^(?:((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))(?:/((?:(?:0)|(?:3[0-2])|(?:[1-2]?[0-9]))))?)$#

If you want to verify the input before using the function

<?php
if (is_string($ipv4) && preg_match('#^(?:((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))\.((?:0)|(?:2(?:(?:[0-4][0-9])|(?:5[0-5])))|(?:1?[0-9]{1,2}))(?:/((?:(?:0)|(?:3[0-2])|(?:[1-2]?[0-9]))))?)$#',$ipv4))
{
#This is a valid ipv4 with or without CIDR Routing Prefix
$result=cidr2range($ipv4);
print_r($result);
}

Then the formal answer to your question is the following

<?php
#Requiring cidr2range shown above function
function cidr_match($mixed_ip,$mixed_cidr){
if (!is_array($mixed_ip)){
$string_mode=true;
$mixed_ip=[$mixed_ip=>0];
}
else $mixed_ip=array_fill_keys($mixed_ip,0);
if (!is_array($mixed_cidr)) $mixed_cidr=[$mixed_cidr];
foreach($mixed_ip   as $ip => &$result)
foreach($mixed_cidr as $cidr)
{
if(($range=cidr2range($cidr)) &&
($check=ip2long($ip))!==false &&
$check>=$range[0] && $check<=$range[1]){
$result=$cidr;
break;
}
}
$mixed_ip=array_filter($mixed_ip);
return $string_mode?($mixed_ip?true:false):$mixed_ip;
}

print '<pre>';

#Your 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"; 
    }
}


#Also working with IP array and/or CIDR array
#If IP array is given then return an array containing IP (keys) matching CIDR (values)
$result=cidr_match($ips,['20.2.0.0/16','10.2.0.0/15']);
foreach($result as $ip => $cidr){
print "$ip is in the $cidr subnet\n"; 
}

You can compile your own function using these examples, hope these few lines have helped you…

Related

Issue when importing dataset: `Error in scan(...): line 1 did not have 145 elements`
Setup HTTP expires headers using PHP and Apache
Merge data frames based on rownames in R
There's a way to access the document folder in iphone/ipad (real device, no simulator)?
How can I always block checkin of a specific file in TFS
Getting Python's unittest results in a tearDown() method
Add a prefix to column names
How to install Typescript typings for google maps
How do I escape a string inside JavaScript code inside an onClick handler?
Drawing rotated text on a HTML5 canvas
When scattering Flask Models, RuntimeError: 'application not registered on db' was raised
Add a css class to a field in wtform