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// -*- C++ -*-
//=============================================================================
/**
* @file SSLIOP_Accept_Strategy.h
*
* $Id$
*
* IIOP/SSL specific accept strategy
*
* @author Ossama Othman <ossama@dre.vanderbilt.edu>
*/
//=============================================================================
#ifndef TAO_SSLIOP_ACCEPT_STRATEGY_H
#define TAO_SSLIOP_ACCEPT_STRATEGY_H
#include /**/ "ace/pre.h"
#include "ace/config-all.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#include "orbsvcs/SSLIOP/SSLIOP_Connection_Handler.h"
#include "tao/Acceptor_Impl.h"
#include "ace/SSL/SSL_SOCK_Acceptor.h"
TAO_BEGIN_VERSIONED_NAMESPACE_DECL
namespace TAO
{
namespace SSLIOP
{
/**
* @class Accept_Strategy
*
* @brief SSLIOP-specific accept strategy that builds on the
* TAO_Accept_Strategy implementation.
*
* This accept strategy builds on on the TAO_Accept_Strategy
* implementation. It sub-classes that class, and overrides the
* accept_svc_handler() method so that a timeout value may be
* passed to the underlying peer acceptor. This is necessary to
* defend against a simple Denial-of-Service attack.
* @par
* Since SSL requires two handshakes, one TCP and one SSL, it is
* possible for a malicious client to establish a TCP connection
* to the SSL port, and never complete the SSL handshake. The
* underlying SSL passive connection code would block/hang waiting
* for the SSL handshake to complete. Given enough incomplete
* connections where only the TCP handshake is completed, a server
* process could potentially run out of available file
* descriptors, thus preventing legitimate client connections from
* being established.
* @par.
* The timeout defense alluded to above bounds the time this sort of
* DoS attack lasts.
*/
class Accept_Strategy
: public TAO_Accept_Strategy<TAO::SSLIOP::Connection_Handler,
ACE_SSL_SOCK_Acceptor>
{
public:
/// Constructor.
Accept_Strategy (TAO_ORB_Core * orb_core,
const ACE_Time_Value & timeout);
/// Overridden method that forces a passive connection timeout value
/// to be passed to the underlying acceptor.
virtual int accept_svc_handler (handler_type * svc_handler);
private:
/// The accept() timeout.
/**
* This timeout includes the overall time to complete the SSL
* handshake. This includes both the TCP handshake and the SSL
* handshake.
*/
const ACE_Time_Value timeout_;
};
} // End SSLIOP namespace
} // End TAO namespace
TAO_END_VERSIONED_NAMESPACE_DECL
#include /**/ "ace/post.h"
#endif /* TAO_SSLIOP_ACCEPT_STRATEGY_H */
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