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106 lines
4.0 KiB
C
106 lines
4.0 KiB
C
/*
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* Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef RATELIM_INTERNAL_H_INCLUDED_
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#define RATELIM_INTERNAL_H_INCLUDED_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "event2/util.h"
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/** A token bucket is an internal structure that tracks how many bytes we are
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* currently willing to read or write on a given bufferevent or group of
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* bufferevents */
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struct ev_token_bucket {
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/** How many bytes are we willing to read or write right now? These
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* values are signed so that we can do "defecit spending" */
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ev_ssize_t read_limit, write_limit;
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/** When was this bucket last updated? Measured in abstract 'ticks'
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* relative to the token bucket configuration. */
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ev_uint32_t last_updated;
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};
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/** Configuration info for a token bucket or set of token buckets. */
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struct ev_token_bucket_cfg {
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/** How many bytes are we willing to read on average per tick? */
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size_t read_rate;
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/** How many bytes are we willing to read at most in any one tick? */
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size_t read_maximum;
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/** How many bytes are we willing to write on average per tick? */
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size_t write_rate;
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/** How many bytes are we willing to write at most in any one tick? */
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size_t write_maximum;
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/* How long is a tick? Note that fractions of a millisecond are
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* ignored. */
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struct timeval tick_timeout;
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/* How long is a tick, in milliseconds? Derived from tick_timeout. */
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unsigned msec_per_tick;
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};
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/** The current tick is 'current_tick': add bytes to 'bucket' as specified in
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* 'cfg'. */
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int ev_token_bucket_update_(struct ev_token_bucket *bucket,
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const struct ev_token_bucket_cfg *cfg,
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ev_uint32_t current_tick);
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/** In which tick does 'tv' fall according to 'cfg'? Note that ticks can
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* overflow easily; your code needs to handle this. */
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ev_uint32_t ev_token_bucket_get_tick_(const struct timeval *tv,
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const struct ev_token_bucket_cfg *cfg);
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/** Adjust 'bucket' to respect 'cfg', and note that it was last updated in
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* 'current_tick'. If 'reinitialize' is true, we are changing the
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* configuration of 'bucket'; otherwise, we are setting it up for the first
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* time.
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*/
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int ev_token_bucket_init_(struct ev_token_bucket *bucket,
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const struct ev_token_bucket_cfg *cfg,
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ev_uint32_t current_tick,
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int reinitialize);
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int bufferevent_remove_from_rate_limit_group_internal_(struct bufferevent *bev,
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int unsuspend);
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/** Decrease the read limit of 'b' by 'n' bytes */
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#define ev_token_bucket_decrement_read(b,n) \
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do { \
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(b)->read_limit -= (n); \
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} while (0)
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/** Decrease the write limit of 'b' by 'n' bytes */
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#define ev_token_bucket_decrement_write(b,n) \
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do { \
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(b)->write_limit -= (n); \
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} while (0)
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#ifdef __cplusplus
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}
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#endif
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#endif
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