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https://github.com/falcosecurity/falco.git
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b2ef08fd30
Signed-off-by: Lorenzo Fontana <lo@linux.com> Co-authored-by: Leonardo Di Donato <leodidonato@gmail.com>
81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
/*
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Copyright (C) 2016-2018 Draios Inc dba Sysdig.
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This file is part of falco.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#pragma once
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#include <cstdint>
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#include <functional>
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// A simple token bucket that accumulates tokens at a fixed rate and allows
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// for limited bursting in the form of "banked" tokens.
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class token_bucket
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{
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public:
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token_bucket();
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token_bucket(std::function<uint64_t()> timer);
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virtual ~token_bucket();
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//
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// Initialize the token bucket and start accumulating tokens
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//
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void init(double rate, double max_tokens, uint64_t now = 0);
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//
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// Try to claim tokens tokens from the token bucket, using a
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// timestamp of now. Returns true if the tokens could be
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// claimed. Also updates internal metrics.
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//
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bool claim(double tokens, uint64_t now);
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// Simpler version of claim that claims a single token and
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// uses the current time for now
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bool claim();
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// Return the current number of tokens available
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double get_tokens();
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// Return the last time someone tried to claim a token.
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uint64_t get_last_seen();
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private:
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std::function<uint64_t()> m_timer;
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//
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// The number of tokens generated per second.
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//
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double m_rate;
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//
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// The maximum number of tokens that can be banked for future
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// claim()s.
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//
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double m_max_tokens;
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//
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// The current number of tokens
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//
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double m_tokens;
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//
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// The last time claim() was called (or the object was created).
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// Nanoseconds since the epoch.
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//
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uint64_t m_last_seen;
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};
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