php语法如何实现避免无限跳转

if(isset($_SERVER['HTTP_REFERER']) && strpos($_SERVER['HTTP_REFERER'], 
'http(s)://'.$_SERVER['HTTP_HOST']) !== false){
  // 如果当前访问页地址与目标跳转页地址一致，则不进行跳转
  exit(); 

}

if($is_mobile){ 
  header('Cache-Control: no-cache, no-store, must-revalidate');
  header('Pragma: no-cache');
  header('Expires: 0');
   
  header('Location: /m/'); // 跳转到移动端首页地址
  exit(); 

}

else{  
  header('Cache-Control: no-cache, no-store, must-revalidate');
  header('Pragma: no-cache');
  header('Expires: 0');
   
  header('Location: /'); // 跳转到PC端首页地址
  exit(); 

}