The Tor Browser: ipc/chromium/src/third_party/libevent/ratelim-internal.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /*

     2  * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  * 1. Redistributions of source code must retain the above copyright

     8  *    notice, this list of conditions and the following disclaimer.

     9  * 2. Redistributions in binary form must reproduce the above copyright

    10  *    notice, this list of conditions and the following disclaimer in the

    11  *    documentation and/or other materials provided with the distribution.

    12  * 3. The name of the author may not be used to endorse or promote products

    13  *    derived from this software without specific prior written permission.

    14  *

    15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

    16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

    17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

    18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

    19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

    20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

    21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

    22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

    24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    25  */

    26 #ifndef _RATELIM_INTERNAL_H_

    27 #define _RATELIM_INTERNAL_H_

    29 #ifdef __cplusplus

    30 extern "C" {

    31 #endif

    33 #include "event2/util.h"

    35 /** A token bucket is an internal structure that tracks how many bytes we are

    36  * currently willing to read or write on a given bufferevent or group of

    37  * bufferevents */

    38 struct ev_token_bucket {

    39 	/** How many bytes are we willing to read or write right now? These

    40 	 * values are signed so that we can do "defecit spending" */

    41 	ev_ssize_t read_limit, write_limit;

    42 	/** When was this bucket last updated?  Measured in abstract 'ticks'

    43 	 * relative to the token bucket configuration. */

    44 	ev_uint32_t last_updated;

    45 };

    47 /** Configuration info for a token bucket or set of token buckets. */

    48 struct ev_token_bucket_cfg {

    49 	/** How many bytes are we willing to read on average per tick? */

    50 	size_t read_rate;

    51 	/** How many bytes are we willing to read at most in any one tick? */

    52 	size_t read_maximum;

    53 	/** How many bytes are we willing to write on average per tick? */

    54 	size_t write_rate;

    55 	/** How many bytes are we willing to write at most in any one tick? */

    56 	size_t write_maximum;

    58 	/* How long is a tick?  Note that fractions of a millisecond are

    59 	 * ignored. */

    60 	struct timeval tick_timeout;

    62 	/* How long is a tick, in milliseconds?  Derived from tick_timeout. */

    63 	unsigned msec_per_tick;

    64 };

    66 /** The current tick is 'current_tick': add bytes to 'bucket' as specified in

    67  * 'cfg'. */

    68 int ev_token_bucket_update(struct ev_token_bucket *bucket,

    69     const struct ev_token_bucket_cfg *cfg,

    70     ev_uint32_t current_tick);

    72 /** In which tick does 'tv' fall according to 'cfg'?  Note that ticks can

    73  * overflow easily; your code needs to handle this. */

    74 ev_uint32_t ev_token_bucket_get_tick(const struct timeval *tv,

    75     const struct ev_token_bucket_cfg *cfg);

    77 /** Adjust 'bucket' to respect 'cfg', and note that it was last updated in

    78  * 'current_tick'.  If 'reinitialize' is true, we are changing the

    79  * configuration of 'bucket'; otherwise, we are setting it up for the first

    80  * time.

    81  */

    82 int ev_token_bucket_init(struct ev_token_bucket *bucket,

    83     const struct ev_token_bucket_cfg *cfg,

    84     ev_uint32_t current_tick,

    85     int reinitialize);

    87 int bufferevent_remove_from_rate_limit_group_internal(struct bufferevent *bev,

    88     int unsuspend);

    90 /** Decrease the read limit of 'b' by 'n' bytes */

    91 #define ev_token_bucket_decrement_read(b,n)	\

    92 	do {					\

    93 		(b)->read_limit -= (n);		\

    94 	} while (0)

    95 /** Decrease the write limit of 'b' by 'n' bytes */

    96 #define ev_token_bucket_decrement_write(b,n)	\

    97 	do {					\

    98 		(b)->write_limit -= (n);	\

    99 	} while (0)

   101 #ifdef __cplusplus

   102 }

   103 #endif

   105 #endif

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