original files of m241

components/ip_net2-6.9/ipntp/include/isc/ratelimiter.h

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+/*
+ * Copyright (C) 2004-2007, 2009  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 1.1.2.1 2015-04-01 02:13:20 lyang3 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 minimum 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 rate limiter 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 */