7fd78344e0
the rate limter now uses loop callbacks rather than task events. the API for isc_ratelimiter_enqueue() has been changed; we now pass in a loop, a callback function and a callback argument, and receive back a rate limiter event object (isc_rlevent_t). it is no longer necessary for the caller to allocate the event. the callback argument needs to include a pointer to the rlevent object so that it can be freed using isc_rlevent_free(), or by dequeueing.
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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#pragma once
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/*****
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***** Module Info
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*****/
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/*! \file isc/ratelimiter.h
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* \brief A rate limiter is a mechanism for dispatching events at a limited
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* rate. This is intended to be used when sending zone maintenance
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* SOA queries, NOTIFY messages, etc.
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*/
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/***
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*** Imports.
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***/
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#include <inttypes.h>
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#include <stdbool.h>
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#include <isc/lang.h>
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#include <isc/loop.h>
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#include <isc/time.h>
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#include <isc/types.h>
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struct isc_rlevent {
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isc_loop_t *loop;
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isc_ratelimiter_t *rl;
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bool canceled;
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isc_job_cb cb;
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void *arg;
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ISC_LINK(isc_rlevent_t) link;
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};
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ISC_LANG_BEGINDECLS
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/*****
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***** Functions.
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*****/
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void
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isc_ratelimiter_create(isc_loop_t *loop, isc_ratelimiter_t **rlp);
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/*%<
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* Create a rate limiter. The execution interval is initially undefined.
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*/
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void
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isc_ratelimiter_setinterval(isc_ratelimiter_t *restrict rl,
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const isc_interval_t *const interval);
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/*!<
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* Set the minimum interval between event executions.
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* The interval value is copied, so the caller need not preserve it.
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*
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* Requires:
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* '*interval' is a nonzero interval.
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*/
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void
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isc_ratelimiter_setpertic(isc_ratelimiter_t *restrict rl,
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const uint32_t perint);
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/*%<
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* Set the number of events processed per interval timer tick.
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* If 'perint' is zero it is treated as 1.
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*/
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void
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isc_ratelimiter_setpushpop(isc_ratelimiter_t *restrict rl, const bool pushpop);
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/*%<
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* Set / clear the ratelimiter to from push pop mode rather
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* first in - first out mode (default).
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*/
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isc_result_t
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isc_ratelimiter_enqueue(isc_ratelimiter_t *restrict rl,
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isc_loop_t *restrict loop, isc_job_cb cb, void *arg,
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isc_rlevent_t **rlep);
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/*%<
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* Queue an event for rate-limited execution.
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*
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* This is similar to doing an isc_async_run() to the 'loop', except
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* that the execution may be delayed to achieve the desired rate of
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* execution.
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*
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* '*rlep' will be set to point to an allocated ratelimiter event,
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* which can be freed by the caller using isc_rlevent_free() when the
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* event fires, or by dequeueing.
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*
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* Requires:
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*\li 'rl' is a valid ratelimiter.
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*\li 'loop ' is non NULL.
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*\li 'rlep' is non NULL and '*rlep' is NULL.
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*/
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isc_result_t
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isc_ratelimiter_dequeue(isc_ratelimiter_t *restrict rl,
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isc_rlevent_t **rleventp);
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/*
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* Dequeue a event off the ratelimiter queue. If the event has not already
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* been posted, it will be freed and '*rleventp' will be set to NULL.
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*
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* Returns:
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* \li ISC_R_NOTFOUND if the event is no longer linked to the rate limiter.
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* \li ISC_R_SUCCESS
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*/
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void
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isc_ratelimiter_shutdown(isc_ratelimiter_t *restrict rl);
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/*%<
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* Shut down a rate limiter.
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*
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* Ensures:
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*\li All pending events are dispatched immediately with
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* rle->canceled set to true.
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*
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*\li Further attempts to enqueue events will fail with
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* #ISC_R_SHUTTINGDOWN.
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*/
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void
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isc_rlevent_free(isc_rlevent_t **rlep);
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/*%<
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* Free the rate limiter event '*rlep'.
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*/
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ISC_REFCOUNT_DECL(isc_ratelimiter);
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/*%<
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* The rate limiter reference counting.
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*/
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ISC_LANG_ENDDECLS
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