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105 lines
4.0 KiB
105 lines
4.0 KiB
/* |
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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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