PrivateBin/lib/trafficlimiter.php

142 lines
3.2 KiB
PHP

<?php
/**
* ZeroBin
*
* a zero-knowledge paste bin
*
* @link http://sebsauvage.net/wiki/doku.php?id=php:zerobin
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license http://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 0.22
*/
/**
* trafficlimiter
*
* Handles traffic limiting, so no user does more than one call per 10 seconds.
*/
class trafficlimiter extends persistence
{
/**
* time limit in seconds, defaults to 10s
*
* @access private
* @static
* @var int
*/
private static $_limit = 10;
/**
* key to fetch IP address
*
* @access private
* @static
* @var string
*/
private static $_ipKey = 'REMOTE_ADDR';
/**
* set the time limit in seconds
*
* @access public
* @static
* @param int $limit
* @return void
*/
public static function setLimit($limit)
{
self::$_limit = $limit;
}
/**
* set configuration options of the traffic limiter
*
* @access public
* @static
* @param configuration $conf
* @return void
*/
public static function setConfiguration(configuration $conf)
{
self::setLimit($conf->getKey('limit', 'traffic'));
self::setPath($conf->getKey('dir', 'traffic'));
if (($option = $conf->getKey('header', 'traffic')) !== null)
{
$httpHeader = 'HTTP_' . $option;
if (array_key_exists($httpHeader, $_SERVER) && !empty($_SERVER[$httpHeader]))
{
self::$_ipKey = $httpHeader;
}
}
}
/**
* get the current visitors IP address
*
* @access public
* @static
* @return string
*/
public static function getIp()
{
return $_SERVER[self::$_ipKey];
}
/**
* traffic limiter
*
* Make sure the IP address makes at most 1 request every 10 seconds.
*
* @access public
* @static
* @throws Exception
* @return bool
*/
public static function canPass()
{
// disable limits if set to less then 1
if (self::$_limit < 1) return true;
$ip = hash_hmac('sha256', self::getIp(), serversalt::get());
$file = 'traffic_limiter.php';
if (!self::_exists($file))
{
self::_store(
$file,
'<?php' . PHP_EOL .
'$GLOBALS[\'traffic_limiter\'] = array();' . PHP_EOL
);
}
$path = self::getPath($file);
require $path;
$now = time();
$tl = $GLOBALS['traffic_limiter'];
// purge file of expired IPs to keep it small
foreach($tl as $key => $time)
{
if ($time + self::$_limit < $now)
{
unset($tl[$key]);
}
}
if (array_key_exists($ip, $tl) && ($tl[$ip] + self::$_limit >= $now))
{
$result = false;
} else {
$tl[$ip] = time();
$result = true;
}
self::_store(
$file,
'<?php' . PHP_EOL .
'$GLOBALS[\'traffic_limiter\'] = ' .
var_export($tl, true) . ';' . PHP_EOL
);
return $result;
}
}