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