Source: ../../bgp/damping.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// vim:set sts=4 ts=8:
// Copyright (c) 2001-2005 International Computer Science Institute
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/bgp/damping.hh,v 1.2 2005/12/06 07:30:58 atanu Exp $
#ifndef __BGP_DAMPING_HH__
#define __BGP_DAMPING_HH__
#include "libxorp/timer.hh"
#include "libxorp/eventloop.hh"
/* Route Flap Damping (RFC2439)
*
* The damping parameters plus general support code.
*/
class Damping {
public:
static const uint32_t FIXED = 1000;
Damping(EventLoop& eventloop);
void set_damping(bool damping);
bool get_damping() const;
void set_half_life(uint32_t half_life);
void set_max_hold_down(uint32_t max_hold_down);
void set_reuse(uint32_t reuse);
void set_cutoff(uint32_t cutoff);
/**
* Get the current clock tick.
*/
uint32_t get_tick() const {
return _tick;
}
/**
* Merit value to use the first time a route is encountered.
*/
uint32_t get_merit() const {
return FIXED;
}
/**
* Compute the merit value given the last time and merit values.
*/
uint32_t compute_merit(uint32_t last_time, uint32_t last_merit) const;
/**
* True of the merit value has passed the cutoff threshold.
*/
bool cutoff(uint32_t merit) const {
return merit > _cutoff;
}
/**
* True of the merit value is above the reuse threshold.
*/
bool reuse(uint32_t merit) const {
return merit > _reuse;
}
/**
* Compute how long the route should be damped in seconds.
* The time for this figure of merit to decay to the reuse threshold.
*/
uint32_t get_reuse_time(uint32_t merit) const;
private:
EventLoop& _eventloop;
bool _damping; // True if damping is enabled.
uint32_t _half_life; // Half life in minutes.
uint32_t _max_hold_down; // Maximum hold down time in minutes.
uint32_t _reuse; // Reuse threshold.
uint32_t _cutoff; // Cutoff threshold.
vector<uint32_t> _decay; // Per tick delay.
uint32_t _tick; // incremented every tick.
XorpTimer _tick_tock; // Timer to increment the tick.
/**
* Called when damping is enabled.
*/
void init();
/**
* Called when damping is disabled.
*/
void halt();
/*
* Called every clock tick.
*/
bool tick();
};
#endif // __BGP_DAMPING_HH__
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