IP Service Check Class

IPService.php

<?php
/**
  Author: Gkiokan Sali
  Date: 2026-03-21  
  Comment: Check if the given IP is in the allowed Ips List or CIDR Range via Subnet.
**/

class IPService
{
    
    public function check($ip){
        $allowedIps = ['127.0.0.1', '::1', 'localhost', '195.0.0.0/8', '172.16.0.0/12', '10.0.0.0/8'];
        $requestIP  = $ip;

        if (!$this->isIpAllowed($requestIP, $allowedIps)) {
            printf("Password Reset Request for is not on the allowed IP Range {$requestIP}");
        }
        
        print("Allowed?");
    }

    private function isIpAllowed($ip, $allowedList)
    {
        foreach ($allowedList as $allowed) {
        	echo "\n[0] isIpAllowed Test for $allowed \n";
        	
            if (strpos($allowed, '/') !== false) {
                // CIDR notation
                if ($this->ipInCidr($ip, $allowed)) {
                    return true;
                }
            } else {
                // Single IP
                if ($ip === $allowed) {
                    return true;
                }
            }
        }
        return false;
    }
    
    private function ipInCidr($ip, $cidr)
    {
        list($subnet, $mask) = explode('/', $cidr);
        
        echo "-[1] ip in CIDR $subnet $mask \n";
        
        if ((filter_var($subnet, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) && 
            (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4))) {
            // IPv4
            $ipLong = ip2long($ip);
            $subnetLong = ip2long($subnet);
            $maskLong = -1 << (32 - $mask);
            $subnetLong &= $maskLong;
            
            echo "--[2] $ipLong, $subnetLong, $maskLong, $subnetLong \n";
            echo "--[2] compare " . ($ipLong & $maskLong) . " = " . $subnetLong . "\n";
            
            return ($ipLong & $maskLong) == $subnetLong;
        }
        
        return false;
    }    
}

// Usage
$do = new P();
$do->sendPasswordResetMailFromInternal('195.201.160.141');