2 * Copyright (C) 2004 Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 1999-2001 Internet Software Consortium.
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
18 /* $Id: ratelimiter.c,v 1.18.2.1 2004/03/09 06:11:50 marka Exp $ */
23 #include <isc/ratelimiter.h>
26 #include <isc/timer.h>
30 isc_ratelimiter_ratelimited,
31 isc_ratelimiter_worklimited,
32 isc_ratelimiter_shuttingdown
33 } isc_ratelimiter_state_t;
35 struct isc_ratelimiter {
41 isc_interval_t interval;
43 isc_ratelimiter_state_t state;
44 isc_event_t shutdownevent;
45 ISC_LIST(isc_event_t) pending;
48 #define ISC_RATELIMITEREVENT_SHUTDOWN (ISC_EVENTCLASS_RATELIMITER + 1)
51 ratelimiter_tick(isc_task_t *task, isc_event_t *event);
54 ratelimiter_shutdowncomplete(isc_task_t *task, isc_event_t *event);
57 isc_ratelimiter_create(isc_mem_t *mctx, isc_timermgr_t *timermgr,
58 isc_task_t *task, isc_ratelimiter_t **ratelimiterp)
61 isc_ratelimiter_t *rl;
62 INSIST(ratelimiterp != NULL && *ratelimiterp == NULL);
64 rl = isc_mem_get(mctx, sizeof(*rl));
66 return ISC_R_NOMEMORY;
70 isc_interval_set(&rl->interval, 0, 0);
73 rl->state = isc_ratelimiter_worklimited;
74 ISC_LIST_INIT(rl->pending);
76 result = isc_mutex_init(&rl->lock);
77 if (result != ISC_R_SUCCESS)
79 result = isc_timer_create(timermgr, isc_timertype_inactive,
80 NULL, NULL, rl->task, ratelimiter_tick,
82 if (result != ISC_R_SUCCESS)
86 * Increment the reference count to indicate that we may
87 * (soon) have events outstanding.
91 ISC_EVENT_INIT(&rl->shutdownevent,
93 0, NULL, ISC_RATELIMITEREVENT_SHUTDOWN,
94 ratelimiter_shutdowncomplete, rl, rl, NULL, NULL);
97 return (ISC_R_SUCCESS);
100 DESTROYLOCK(&rl->lock);
102 isc_mem_put(mctx, rl, sizeof(*rl));
107 isc_ratelimiter_setinterval(isc_ratelimiter_t *rl, isc_interval_t *interval) {
108 isc_result_t result = ISC_R_SUCCESS;
110 rl->interval = *interval;
112 * If the timer is currently running, change its rate.
114 if (rl->state == isc_ratelimiter_ratelimited) {
115 result = isc_timer_reset(rl->timer, isc_timertype_ticker, NULL,
116 &rl->interval, ISC_FALSE);
123 isc_ratelimiter_setpertic(isc_ratelimiter_t *rl, isc_uint32_t pertic) {
130 isc_ratelimiter_enqueue(isc_ratelimiter_t *rl, isc_task_t *task,
131 isc_event_t **eventp)
133 isc_result_t result = ISC_R_SUCCESS;
136 REQUIRE(eventp != NULL && *eventp != NULL);
137 REQUIRE(task != NULL);
139 REQUIRE(ev->ev_sender == NULL);
142 if (rl->state == isc_ratelimiter_ratelimited) {
143 isc_event_t *ev = *eventp;
144 ev->ev_sender = task;
145 ISC_LIST_APPEND(rl->pending, ev, ev_link);
147 } else if (rl->state == isc_ratelimiter_worklimited) {
148 result = isc_timer_reset(rl->timer, isc_timertype_ticker, NULL,
149 &rl->interval, ISC_FALSE);
150 if (result == ISC_R_SUCCESS) {
151 ev->ev_sender = task;
152 rl->state = isc_ratelimiter_ratelimited;
155 INSIST(rl->state == isc_ratelimiter_shuttingdown);
156 result = ISC_R_SHUTTINGDOWN;
159 if (*eventp != NULL && result == ISC_R_SUCCESS)
160 isc_task_send(task, eventp);
165 ratelimiter_tick(isc_task_t *task, isc_event_t *event) {
166 isc_result_t result = ISC_R_SUCCESS;
167 isc_ratelimiter_t *rl = (isc_ratelimiter_t *)event->ev_arg;
173 isc_event_free(&event);
176 while (pertic != 0) {
179 p = ISC_LIST_HEAD(rl->pending);
182 * There is work to do. Let's do it after unlocking.
184 ISC_LIST_UNLINK(rl->pending, p, ev_link);
187 * No work left to do. Stop the timer so that we don't
188 * waste resources by having it fire periodically.
190 result = isc_timer_reset(rl->timer,
191 isc_timertype_inactive,
192 NULL, NULL, ISC_FALSE);
193 RUNTIME_CHECK(result == ISC_R_SUCCESS);
194 rl->state = isc_ratelimiter_worklimited;
195 pertic = 0; /* Force the loop to exit. */
199 isc_task_t *evtask = p->ev_sender;
200 isc_task_send(evtask, &p);
207 isc_ratelimiter_shutdown(isc_ratelimiter_t *rl) {
211 rl->state = isc_ratelimiter_shuttingdown;
212 (void)isc_timer_reset(rl->timer, isc_timertype_inactive,
213 NULL, NULL, ISC_FALSE);
214 while ((ev = ISC_LIST_HEAD(rl->pending)) != NULL) {
215 ISC_LIST_UNLINK(rl->pending, ev, ev_link);
216 ev->ev_attributes |= ISC_EVENTATTR_CANCELED;
217 task = ev->ev_sender;
218 isc_task_send(task, &ev);
220 isc_timer_detach(&rl->timer);
222 * Send an event to our task. The delivery of this event
223 * indicates that no more timer events will be delivered.
225 ev = &rl->shutdownevent;
226 isc_task_send(rl->task, &ev);
232 ratelimiter_shutdowncomplete(isc_task_t *task, isc_event_t *event) {
233 isc_ratelimiter_t *rl = (isc_ratelimiter_t *)event->ev_arg;
237 isc_ratelimiter_detach(&rl);
241 ratelimiter_free(isc_ratelimiter_t *rl) {
242 DESTROYLOCK(&rl->lock);
243 isc_mem_put(rl->mctx, rl, sizeof(*rl));
247 isc_ratelimiter_attach(isc_ratelimiter_t *source, isc_ratelimiter_t **target) {
248 REQUIRE(source != NULL);
249 REQUIRE(target != NULL && *target == NULL);
252 REQUIRE(source->refs > 0);
254 INSIST(source->refs > 0);
255 UNLOCK(&source->lock);
260 isc_ratelimiter_detach(isc_ratelimiter_t **rlp) {
261 isc_ratelimiter_t *rl = *rlp;
262 isc_boolean_t free_now = ISC_FALSE;
265 REQUIRE(rl->refs > 0);
272 ratelimiter_free(rl);