diff options
Diffstat (limited to 'libs/libevent/src/ratelim-internal.h')
| -rw-r--r-- | libs/libevent/src/ratelim-internal.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/libs/libevent/src/ratelim-internal.h b/libs/libevent/src/ratelim-internal.h new file mode 100644 index 0000000000..6cc1cdde2c --- /dev/null +++ b/libs/libevent/src/ratelim-internal.h @@ -0,0 +1,105 @@ +/* + * 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_INCLUDED_ +#define RATELIM_INTERNAL_H_INCLUDED_ + +#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 |