mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-24 15:16:40 +00:00
139 lines
3.5 KiB
C++
139 lines
3.5 KiB
C++
/*
|
|
* ZeroTier One - Global Peer to Peer Ethernet
|
|
* Copyright (C) 2012-2013 ZeroTier Networks LLC
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* --
|
|
*
|
|
* ZeroTier may be used and distributed under the terms of the GPLv3, which
|
|
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
|
|
*
|
|
* If you would like to embed ZeroTier into a commercial application or
|
|
* redistribute it in a modified binary form, please contact ZeroTier Networks
|
|
* LLC. Start here: http://www.zerotier.com/
|
|
*/
|
|
|
|
#ifndef _ZT_RATELIMITER_HPP
|
|
#define _ZT_RATELIMITER_HPP
|
|
|
|
#include <math.h>
|
|
#include "Utils.hpp"
|
|
|
|
namespace ZeroTier {
|
|
|
|
/**
|
|
* Burstable rate limiter
|
|
*
|
|
* This limits a transfer rate to a maximum bytes per second using an
|
|
* accounting method based on a balance rather than accumulating an
|
|
* average rate. The result is a burstable rate limit rather than a
|
|
* continuous rate limit; the link being limited may use all its balance
|
|
* at once or slowly over time. Balance constantly replenishes over time
|
|
* up to a configurable maximum balance.
|
|
*/
|
|
class RateLimiter
|
|
{
|
|
public:
|
|
/**
|
|
* Limits to apply to a rate limiter
|
|
*
|
|
* Since many rate limiters may share the same fixed limit values,
|
|
* save memory by breaking this out into a struct parameter that
|
|
* can be passed into RateLimiter's methods.
|
|
*/
|
|
struct Limit
|
|
{
|
|
/**
|
|
* Speed in bytes per second, or rate of balance accrual
|
|
*/
|
|
double bytesPerSecond;
|
|
|
|
/**
|
|
* Maximum balance that can ever be accrued (should be > 0.0)
|
|
*/
|
|
double maxBalance;
|
|
|
|
/**
|
|
* Minimum balance, or maximum allowable "debt" (should be <= 0.0)
|
|
*/
|
|
double minBalance;
|
|
};
|
|
|
|
/**
|
|
* Create an uninitialized rate limiter
|
|
*
|
|
* init() must be called before this is used.
|
|
*/
|
|
RateLimiter() throw() {}
|
|
|
|
/**
|
|
* @param preload Initial balance to place in account
|
|
*/
|
|
RateLimiter(double preload)
|
|
throw()
|
|
{
|
|
init(preload);
|
|
}
|
|
|
|
/**
|
|
* Initialize or re-initialize rate limiter
|
|
*
|
|
* @param preload Initial balance to place in account
|
|
*/
|
|
inline void init(double preload)
|
|
throw()
|
|
{
|
|
_lastTime = Utils::nowf();
|
|
_balance = preload;
|
|
}
|
|
|
|
/**
|
|
* Update balance based on current clock and supplied Limits bytesPerSecond and maxBalance
|
|
*
|
|
* @param lim Current limits in effect
|
|
* @return New balance
|
|
*/
|
|
inline double updateBalance(const Limit &lim)
|
|
throw()
|
|
{
|
|
double lt = _lastTime;
|
|
double now = _lastTime = Utils::nowf();
|
|
return (_balance = fmin(lim.maxBalance,_balance + (lim.bytesPerSecond * (now - lt))));
|
|
}
|
|
|
|
/**
|
|
* Update balance and test if a block of 'bytes' should be permitted to be transferred
|
|
*
|
|
* @param lim Current limits in effect
|
|
* @param bytes Number of bytes that we wish to transfer
|
|
* @return True if balance was sufficient
|
|
*/
|
|
inline bool gate(const Limit &lim,double bytes)
|
|
throw()
|
|
{
|
|
bool allow = (updateBalance(lim) >= bytes);
|
|
_balance = fmax(lim.minBalance,_balance - bytes);
|
|
return allow;
|
|
}
|
|
|
|
private:
|
|
double _lastTime;
|
|
double _balance;
|
|
};
|
|
|
|
} // namespace ZeroTier
|
|
|
|
#endif
|