Get visitor IP address in PHP

$_SERVER.php

function get_visitor_ip() {
    $ip = '';
    if ($_SERVER['HTTP_CLIENT_IP'])
        $ip = $_SERVER['HTTP_CLIENT_IP'];
    else if($_SERVER['HTTP_X_FORWARDED_FOR'])
        $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
    else if($_SERVER['HTTP_X_FORWARDED'])
        $ip = $_SERVER['HTTP_X_FORWARDED'];
    else if($_SERVER['HTTP_FORWARDED_FOR'])
        $ip = $_SERVER['HTTP_FORWARDED_FOR'];
    else if($_SERVER['HTTP_FORWARDED'])
        $ip = $_SERVER['HTTP_FORWARDED'];
    else if($_SERVER['REMOTE_ADDR'])
        $ip = $_SERVER['REMOTE_ADDR'];
    else
        $ip = 'none';
  
    return $ip;
}

getenv-function.php

function get_visitor_ip()  {
    $ip = '';
    if (getenv('HTTP_CLIENT_IP'))
        $ip = getenv('HTTP_CLIENT_IP');
    else if(getenv('HTTP_X_FORWARDED_FOR'))
        $ip = getenv('HTTP_X_FORWARDED_FOR');
    else if(getenv('HTTP_X_FORWARDED'))
        $ip = getenv('HTTP_X_FORWARDED');
    else if(getenv('HTTP_FORWARDED_FOR'))
        $ip = getenv('HTTP_FORWARDED_FOR');
    else if(getenv('HTTP_FORWARDED'))
        $ip = getenv('HTTP_FORWARDED');
    else if(getenv('REMOTE_ADDR'))
        $ip = getenv('REMOTE_ADDR');
    else
        $ip = 'none';
  
    return $ip;
}