1275970Scy/* 2275970Scy * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson 3275970Scy * 4275970Scy * Redistribution and use in source and binary forms, with or without 5275970Scy * modification, are permitted provided that the following conditions 6275970Scy * are met: 7275970Scy * 1. Redistributions of source code must retain the above copyright 8275970Scy * notice, this list of conditions and the following disclaimer. 9275970Scy * 2. Redistributions in binary form must reproduce the above copyright 10275970Scy * notice, this list of conditions and the following disclaimer in the 11275970Scy * documentation and/or other materials provided with the distribution. 12275970Scy * 3. The name of the author may not be used to endorse or promote products 13275970Scy * derived from this software without specific prior written permission. 14275970Scy * 15275970Scy * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16275970Scy * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17275970Scy * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18275970Scy * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19275970Scy * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20275970Scy * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21275970Scy * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22275970Scy * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23275970Scy * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24275970Scy * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25275970Scy */ 26275970Scy#ifndef RATELIM_INTERNAL_H_INCLUDED_ 27275970Scy#define RATELIM_INTERNAL_H_INCLUDED_ 28275970Scy 29275970Scy#ifdef __cplusplus 30275970Scyextern "C" { 31275970Scy#endif 32275970Scy 33275970Scy#include "event2/util.h" 34275970Scy 35275970Scy/** A token bucket is an internal structure that tracks how many bytes we are 36275970Scy * currently willing to read or write on a given bufferevent or group of 37275970Scy * bufferevents */ 38275970Scystruct ev_token_bucket { 39275970Scy /** How many bytes are we willing to read or write right now? These 40275970Scy * values are signed so that we can do "defecit spending" */ 41275970Scy ev_ssize_t read_limit, write_limit; 42275970Scy /** When was this bucket last updated? Measured in abstract 'ticks' 43275970Scy * relative to the token bucket configuration. */ 44275970Scy ev_uint32_t last_updated; 45275970Scy}; 46275970Scy 47275970Scy/** Configuration info for a token bucket or set of token buckets. */ 48275970Scystruct ev_token_bucket_cfg { 49275970Scy /** How many bytes are we willing to read on average per tick? */ 50275970Scy size_t read_rate; 51275970Scy /** How many bytes are we willing to read at most in any one tick? */ 52275970Scy size_t read_maximum; 53275970Scy /** How many bytes are we willing to write on average per tick? */ 54275970Scy size_t write_rate; 55275970Scy /** How many bytes are we willing to write at most in any one tick? */ 56275970Scy size_t write_maximum; 57275970Scy 58275970Scy /* How long is a tick? Note that fractions of a millisecond are 59275970Scy * ignored. */ 60275970Scy struct timeval tick_timeout; 61275970Scy 62275970Scy /* How long is a tick, in milliseconds? Derived from tick_timeout. */ 63275970Scy unsigned msec_per_tick; 64275970Scy}; 65275970Scy 66275970Scy/** The current tick is 'current_tick': add bytes to 'bucket' as specified in 67275970Scy * 'cfg'. */ 68275970Scyint ev_token_bucket_update_(struct ev_token_bucket *bucket, 69275970Scy const struct ev_token_bucket_cfg *cfg, 70275970Scy ev_uint32_t current_tick); 71275970Scy 72275970Scy/** In which tick does 'tv' fall according to 'cfg'? Note that ticks can 73275970Scy * overflow easily; your code needs to handle this. */ 74275970Scyev_uint32_t ev_token_bucket_get_tick_(const struct timeval *tv, 75275970Scy const struct ev_token_bucket_cfg *cfg); 76275970Scy 77275970Scy/** Adjust 'bucket' to respect 'cfg', and note that it was last updated in 78275970Scy * 'current_tick'. If 'reinitialize' is true, we are changing the 79275970Scy * configuration of 'bucket'; otherwise, we are setting it up for the first 80275970Scy * time. 81275970Scy */ 82275970Scyint ev_token_bucket_init_(struct ev_token_bucket *bucket, 83275970Scy const struct ev_token_bucket_cfg *cfg, 84275970Scy ev_uint32_t current_tick, 85275970Scy int reinitialize); 86275970Scy 87275970Scyint bufferevent_remove_from_rate_limit_group_internal_(struct bufferevent *bev, 88275970Scy int unsuspend); 89275970Scy 90275970Scy/** Decrease the read limit of 'b' by 'n' bytes */ 91275970Scy#define ev_token_bucket_decrement_read(b,n) \ 92275970Scy do { \ 93275970Scy (b)->read_limit -= (n); \ 94275970Scy } while (0) 95275970Scy/** Decrease the write limit of 'b' by 'n' bytes */ 96275970Scy#define ev_token_bucket_decrement_write(b,n) \ 97275970Scy do { \ 98275970Scy (b)->write_limit -= (n); \ 99275970Scy } while (0) 100275970Scy 101275970Scy#ifdef __cplusplus 102275970Scy} 103275970Scy#endif 104275970Scy 105275970Scy#endif 106