Polling.php

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<?php

namespace Rsi\Fred\Security\Check;

class Polling extends \Rsi\Fred\Security\Check{

  public $filters = [];
  public $ext = '.pol'; //!< Extension for times file.
  public $checkTtl = 3600; //!< Re-use polling info for this amount of time (seconds).
  public $timeDelta = 5; //!< Consider everything between this amount of seconds as a single request.
  public $countThreshold = 100; //!< Minimum number of requests.
  public $deviationPerc = 5; //!< Consider a deviation within this percentage of the average a poller.
  public $logPrio = \Rsi\Fred\Log::WARNING; //!< Log prio for the warning message.

  protected $_path = null;
  protected $_pollerFilename = null; //!< File with IP addresses of pollers (extension must differ from times files or other
    // directory; defaults to poller.csv in times file path).

  protected function filename($addr = null){
    return $this->path . str_replace(['.',':'],'-',$addr ?: $this->component('security')->remoteAddr) . $this->ext;
  }

  protected function addTime($filter){
    $exists = is_file($filename = $this->filename());
    $f = fopen($filename,$exists ? 'a' : 'w');
    if(!$exists) fwrite($f,$this->component('security')->remoteAddr . "\n");
    fwrite($f,time() . "\n");
    fclose($f);
    if(!$exists) chmod($filename,0666);
  }

  protected function isPoller(){
    return is_file($this->pollerFilename) && in_array($this->component('security')->remoteAddr,file($this->pollerFilename,FILE_IGNORE_NEW_LINES));
  }

  public function check($expected = false){
    if($expected) return true;
    $result = null;
    try{
      if(
        ($url = $_SERVER['REQUEST_URI'] ?? null) &&
        ($this->session->lastTime < $this->_fred->startTime - $this->timeDelta)
      ) foreach($this->filters as $name => $filter) if(preg_match($filter,$url)){
        $this->addTime($name);
        $this->session->lastTime = time();
        break;
      }
      if((($result = $this->session->lastResult) === null) || ($this->session->lastCheck < $this->_fred->startTime - $this->checkTtl)){
        $this->session->lastResult = $result = !$this->isPoller();
        $this->session->lastCheck = $this->_fred->startTime;
      }
    }
    catch(\Exception $e){
      if($this->_fred->debug) throw $e;
    }
    return $result;
  }

  protected function analyseTimes($addr,$times){
    $result = false;
    if(count($times) > $this->countThreshold){
      $total = $count = $prev = 0;
      $polls = [];
      foreach($times as $time){
        if($prev && ($time > $prev + $this->timeDelta)){
          if(!$polls) $polls[] = $prev;
          $polls[] = $time;
          $total += $time - $prev;
          $count++;
        }
        $prev = $time;
      }
      if($count > $this->countThreshold){
        $average = $total / $count;
        $total = $prev = 0;
        foreach($polls as $time){
          if($prev) $total += pow($time - $prev - $average,2);
          $prev = $time;
        }
        if($result = ($deviation = 100 * sqrt($total / $count) / $average) < $this->deviationPerc)
          $this->component('log')->add($this->logPrio,"IP address $addr is polling: count = $count, average = " . number_format($average) . ", deviation% = " . number_format($deviation,2),__FILE__,__LINE__);
      }
    }
    return $result;
  }
  /**
   * Analyse the times files, and compile a list of pollers.
   * Run this function periodically.
   */
  public function analyse(){
    $pollers = [];
    foreach((new \GlobIterator($this->path . '*' . $this->ext)) as $filename => $file){
      $lines = file($filename,FILE_IGNORE_NEW_LINES);
      \Rsi\File::unlink($filename);
      $addr = array_shift($lines);
      if($this->analyseTimes($addr,$lines)) $pollers[] = $addr;
    }
    file_put_contents($this->pollerFilename,implode("\n",$pollers));
  }

  public function unBan($addr){
    return \Rsi\File::unlink($this->filename($addr));
  }

  protected function getPath(){
    if(!$this->_path) $this->_path = $this->component('security')->path;
    return $this->_path;
  }

  protected function getPollerFilename(){
    return $this->_pollerFilename ?: $this->path . 'pollers.csv';
  }

}