ip.php

<?php

if (!function_exists('is_valid_ip')) {
    // PHP ≥ 8.0
    function is_valid_ip(string $ip, ?string $type = null): bool
    {
        return false !== match ($type) {
                'IPv4' => filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4),
                'IPv6' => filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6),
                default => filter_var($ip, FILTER_VALIDATE_IP),
            };
    }
}