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