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/*
* Copyright © 2008-2011 Kristian Høgsberg
* Copyright © 2011 Intel Corporation
* Copyright © 2013-2015 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "config.h"
#include <time.h>
#include "util-ratelimit.h"
#include "util-time.h"
void
ratelimit_init(struct ratelimit *r, uint64_t ival_us, unsigned int burst)
{
r->interval = ival_us;
r->begin = 0;
r->burst = burst;
r->num = 0;
}
/*
* Perform rate-limit test. Returns RATELIMIT_PASS if the rate-limited action
* is still allowed, RATELIMIT_THRESHOLD if the limit has been reached with
* this call, and RATELIMIT_EXCEEDED if you're beyond the threshold.
* It's safe to treat the return-value as boolean, if you're not interested in
* the exact state. It evaluates to "true" if the threshold hasn't been
* exceeded, yet.
*
* The ratelimit object must be initialized via ratelimit_init().
*
* Modelled after Linux' lib/ratelimit.c by Dave Young
* <hidave.darkstar@gmail.com>, which is licensed GPLv2.
*/
enum ratelimit_state
ratelimit_test(struct ratelimit *r)
{
struct timespec ts;
uint64_t utime;
if (r->interval <= 0 || r->burst <= 0)
return RATELIMIT_PASS;
clock_gettime(CLOCK_MONOTONIC, &ts);
utime = s2us(ts.tv_sec) + ns2us(ts.tv_nsec);
if (r->begin <= 0 || r->begin + r->interval < utime) {
/* reset counter */
r->begin = utime;
r->num = 1;
return RATELIMIT_PASS;
} else if (r->num < r->burst) {
/* continue burst */
return (++r->num == r->burst) ? RATELIMIT_THRESHOLD
: RATELIMIT_PASS;
}
return RATELIMIT_EXCEEDED;
}
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