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132 lines
3.3 KiB
132 lines
3.3 KiB
/* |
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* ZeroTier One - Global Peer to Peer Ethernet |
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* Copyright (C) 2012-2013 ZeroTier Networks LLC |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>. |
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* |
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* -- |
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* |
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* ZeroTier may be used and distributed under the terms of the GPLv3, which |
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* are available at: http://www.gnu.org/licenses/gpl-3.0.html |
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* |
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* If you would like to embed ZeroTier into a commercial application or |
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* redistribute it in a modified binary form, please contact ZeroTier Networks |
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* LLC. Start here: http://www.zerotier.com/ |
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*/ |
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#ifndef _ZT_RATELIMITER_HPP |
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#define _ZT_RATELIMITER_HPP |
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#include <math.h> |
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#include "Constants.hpp" |
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#include "Utils.hpp" |
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#ifdef __WINDOWS__ |
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#define fmin(a,b) (((a) <= (b)) ? (a) : (b)) |
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#define fmax(a,b) (((a) >= (b)) ? (a) : (b)) |
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#endif |
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namespace ZeroTier { |
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/** |
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* Data transfer accounting used for multicast groups |
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* |
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* This is used to apply a bank account model to multicast groups. Each |
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* multicast packet counts against a balance, which accrues at a given |
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* rate in bytes per second. Debt is possible. These parameters are |
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* configurable. |
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* |
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* A bank account model permits bursting behavior, which correctly models |
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* how OSes and apps typically use multicast. It's common for things to |
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* spew lots of multicast messages at once, wait a while, then do it |
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* again. A consistent bandwidth limit model doesn't fit. |
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*/ |
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class RateLimiter |
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{ |
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public: |
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/** |
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* Rate and min/max to apply on rate limiter update |
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*/ |
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struct Rate |
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{ |
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/** |
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* Rate of balance accrual in bytes per second |
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*/ |
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double bytesPerSecond; |
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/** |
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* Maximum balance that can ever be accrued (should be > 0.0) |
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*/ |
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double maxBalance; |
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/** |
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* Minimum balance, or maximum allowable "debt" (should be <= 0.0) |
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*/ |
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double minBalance; |
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}; |
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/** |
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* Create an uninitialized rate limiter |
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* |
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* init() must be called before this is used. |
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*/ |
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RateLimiter() throw() {} |
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/** |
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* Create an initialize rate limiter |
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* |
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* @param preload Initial balance to place in account |
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*/ |
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RateLimiter(double preload) |
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throw() |
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{ |
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init(preload); |
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} |
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/** |
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* Initialize or re-initialize rate limiter |
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* |
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* @param preload Initial balance to place in account |
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*/ |
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inline void init(double preload) |
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throw() |
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{ |
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_lastTime = Utils::nowf(); |
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_balance = preload; |
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} |
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/** |
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* Update balance based on current clock and supplied rate |
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* |
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* @param lim Current limits in effect |
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* @param deduct Amount to deduct, or 0.0 to just update |
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* @return New balance with deduction applied |
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*/ |
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inline double update(const Rate &r,double deduct) |
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throw() |
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{ |
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double lt = _lastTime; |
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double now = _lastTime = Utils::nowf(); |
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return (_balance = fmax(r.minBalance,fmin(r.maxBalance,(_balance + (r.bytesPerSecond * (now - lt))) - deduct))); |
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} |
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private: |
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double _lastTime; |
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double _balance; |
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}; |
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} // namespace ZeroTier |
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#endif
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