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Diffstat (limited to 'lib/isc/include/isc/ratelimiter.h')
| -rw-r--r-- | lib/isc/include/isc/ratelimiter.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/lib/isc/include/isc/ratelimiter.h b/lib/isc/include/isc/ratelimiter.h new file mode 100644 index 0000000..03da2d0 --- /dev/null +++ b/lib/isc/include/isc/ratelimiter.h @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC") + * Copyright (C) 1999-2002 Internet Software Consortium. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +/* $Id: ratelimiter.h,v 1.21 2007/06/19 23:47:18 tbox Exp $ */ + +#ifndef ISC_RATELIMITER_H +#define ISC_RATELIMITER_H 1 + +/***** + ***** Module Info + *****/ + +/*! \file isc/ratelimiter.h + * \brief A rate limiter is a mechanism for dispatching events at a limited + * rate. This is intended to be used when sending zone maintenance + * SOA queries, NOTIFY messages, etc. + */ + +/*** + *** Imports. + ***/ + +#include <isc/lang.h> +#include <isc/types.h> + +ISC_LANG_BEGINDECLS + +/***** + ***** Functions. + *****/ + +isc_result_t +isc_ratelimiter_create(isc_mem_t *mctx, isc_timermgr_t *timermgr, + isc_task_t *task, isc_ratelimiter_t **ratelimiterp); +/*%< + * Create a rate limiter. The execution interval is initially undefined. + */ + +isc_result_t +isc_ratelimiter_setinterval(isc_ratelimiter_t *rl, isc_interval_t *interval); +/*!< + * Set the mininum interval between event executions. + * The interval value is copied, so the caller need not preserve it. + * + * Requires: + * '*interval' is a nonzero interval. + */ + +void +isc_ratelimiter_setpertic(isc_ratelimiter_t *rl, isc_uint32_t perint); +/*%< + * Set the number of events processed per interval timer tick. + * If 'perint' is zero it is treated as 1. + */ + +isc_result_t +isc_ratelimiter_enqueue(isc_ratelimiter_t *rl, isc_task_t *task, + isc_event_t **eventp); +/*%< + * Queue an event for rate-limited execution. + * + * This is similar + * to doing an isc_task_send() to the 'task', except that the + * execution may be delayed to achieve the desired rate of + * execution. + * + * '(*eventp)->ev_sender' is used to hold the task. The caller + * must ensure that the task exists until the event is delivered. + * + * Requires: + *\li An interval has been set by calling + * isc_ratelimiter_setinterval(). + * + *\li 'task' to be non NULL. + *\li '(*eventp)->ev_sender' to be NULL. + */ + +void +isc_ratelimiter_shutdown(isc_ratelimiter_t *ratelimiter); +/*%< + * Shut down a rate limiter. + * + * Ensures: + *\li All events that have not yet been + * dispatched to the task are dispatched immediately with + * the #ISC_EVENTATTR_CANCELED bit set in ev_attributes. + * + *\li Further attempts to enqueue events will fail with + * #ISC_R_SHUTTINGDOWN. + * + *\li The reatelimiter is no longer attached to its task. + */ + +void +isc_ratelimiter_attach(isc_ratelimiter_t *source, isc_ratelimiter_t **target); +/*%< + * Attach to a rate limiter. + */ + +void +isc_ratelimiter_detach(isc_ratelimiter_t **ratelimiterp); +/*%< + * Detach from a rate limiter. + */ + +isc_result_t +isc_ratelimiter_stall(isc_ratelimiter_t *rl); +/*%< + * Stall event processing. + */ + +isc_result_t +isc_ratelimiter_release(isc_ratelimiter_t *rl); +/*%< + * Release a stalled rate limiter. + */ + +ISC_LANG_ENDDECLS + +#endif /* ISC_RATELIMITER_H */ |