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40 lines
1.1 KiB
40 lines
1.1 KiB
3 months ago
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/*
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* UCW Library -- Rate Limiting based on the Token Bucket Filter
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*
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* (c) 2009 Martin Mares <mj@ucw.cz>
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*
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* This software may be freely distributed and used according to the terms
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* of the GNU Lesser General Public License.
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*/
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#ifndef _UCW_TBF_H_
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#define _UCW_TBF_H_
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#ifdef CONFIG_UCW_CLEAN_ABI
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#define tbf_init ucw_tbf_init
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#define tbf_limit ucw_tbf_limit
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#endif
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/** A data structure describing a single TBF. **/
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struct token_bucket_filter {
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double rate; // Number of tokens received per second
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uint burst; // Capacity of the bucket
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timestamp_t last_hit; // Internal state...
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double bucket;
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uint drop_count;
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};
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/** Initialize the bucket. **/
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void tbf_init(struct token_bucket_filter *f);
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/**
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* Ask the filter to process a single event. Returns a negative number
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* if the event exceeds the rate (and should be dropped) and a non-negative
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* number if the event passes the filter.
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* The absolute value of the result is the number of dropped events
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* since the last passed event.
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**/
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int tbf_limit(struct token_bucket_filter *f, timestamp_t now);
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#endif
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