1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #include <stdlib.h>
27 #include <limits.h>
28 #include <sys/time.h>
29 #include <sys/types.h>
30 #include <sys/sysmacros.h>
31 #include <sys/stropts.h> /* INFTIM */
32
33 #include <libinetutil.h>
34 #include "libinetutil_impl.h"
35
36 static iu_timer_node_t *pending_delete_chain = NULL;
37
38 static void destroy_timer(iu_tq_t *, iu_timer_node_t *);
39 static iu_timer_id_t get_timer_id(iu_tq_t *);
40 static void release_timer_id(iu_tq_t *, iu_timer_id_t);
41
42 /*
43 * iu_tq_create(): creates, initializes and returns a timer queue for use
44 *
45 * input: void
46 * output: iu_tq_t *: the new timer queue
47 */
48
49 iu_tq_t *
iu_tq_create(void)50 iu_tq_create(void)
51 {
52 return (calloc(1, sizeof (iu_tq_t)));
53 }
54
55 /*
56 * iu_tq_destroy(): destroys an existing timer queue
57 *
58 * input: iu_tq_t *: the timer queue to destroy
59 * output: void
60 */
61
62 void
iu_tq_destroy(iu_tq_t * tq)63 iu_tq_destroy(iu_tq_t *tq)
64 {
65 iu_timer_node_t *node, *next_node;
66
67 for (node = tq->iutq_head; node != NULL; node = next_node) {
68 next_node = node->iutn_next;
69 destroy_timer(tq, node);
70 }
71
72 free(tq);
73 }
74
75 /*
76 * insert_timer(): inserts a timer node into a tq's timer list
77 *
78 * input: iu_tq_t *: the timer queue
79 * iu_timer_node_t *: the timer node to insert into the list
80 * uint64_t: the number of milliseconds before this timer fires
81 * output: void
82 */
83
84 static void
insert_timer(iu_tq_t * tq,iu_timer_node_t * node,uint64_t msec)85 insert_timer(iu_tq_t *tq, iu_timer_node_t *node, uint64_t msec)
86 {
87 iu_timer_node_t *after = NULL;
88
89 /*
90 * find the node to insert this new node "after". we do this
91 * instead of the more intuitive "insert before" because with
92 * the insert before approach, a null `before' node pointer
93 * is overloaded in meaning (it could be null because there
94 * are no items in the list, or it could be null because this
95 * is the last item on the list, which are very different cases).
96 */
97
98 node->iutn_abs_timeout = gethrtime() + MSEC2NSEC(msec);
99
100 if (tq->iutq_head != NULL &&
101 tq->iutq_head->iutn_abs_timeout < node->iutn_abs_timeout)
102 for (after = tq->iutq_head; after->iutn_next != NULL;
103 after = after->iutn_next)
104 if (after->iutn_next->iutn_abs_timeout >
105 node->iutn_abs_timeout)
106 break;
107
108 node->iutn_next = after ? after->iutn_next : tq->iutq_head;
109 node->iutn_prev = after;
110 if (after == NULL)
111 tq->iutq_head = node;
112 else
113 after->iutn_next = node;
114
115 if (node->iutn_next != NULL)
116 node->iutn_next->iutn_prev = node;
117 }
118
119 /*
120 * remove_timer(): removes a timer node from the tq's timer list
121 *
122 * input: iu_tq_t *: the timer queue
123 * iu_timer_node_t *: the timer node to remove from the list
124 * output: void
125 */
126
127 static void
remove_timer(iu_tq_t * tq,iu_timer_node_t * node)128 remove_timer(iu_tq_t *tq, iu_timer_node_t *node)
129 {
130 if (node->iutn_next != NULL)
131 node->iutn_next->iutn_prev = node->iutn_prev;
132 if (node->iutn_prev != NULL)
133 node->iutn_prev->iutn_next = node->iutn_next;
134 else
135 tq->iutq_head = node->iutn_next;
136 }
137
138 /*
139 * destroy_timer(): destroy a timer node
140 *
141 * input: iu_tq_t *: the timer queue the timer node is associated with
142 * iu_timer_node_t *: the node to free
143 * output: void
144 */
145
146 static void
destroy_timer(iu_tq_t * tq,iu_timer_node_t * node)147 destroy_timer(iu_tq_t *tq, iu_timer_node_t *node)
148 {
149 release_timer_id(tq, node->iutn_timer_id);
150
151 /*
152 * if we're in expire, don't delete the node yet, since it may
153 * still be referencing it (through the expire_next pointers)
154 */
155
156 if (tq->iutq_in_expire) {
157 node->iutn_pending_delete++;
158 node->iutn_next = pending_delete_chain;
159 pending_delete_chain = node;
160 } else
161 free(node);
162
163 }
164
165 /*
166 * iu_schedule_timer(): creates and inserts a timer in the tq's timer list
167 *
168 * input: iu_tq_t *: the timer queue
169 * uint32_t: the number of seconds before this timer fires
170 * iu_tq_callback_t *: the function to call when the timer fires
171 * void *: an argument to pass to the called back function
172 * output: iu_timer_id_t: the new timer's timer id on success, -1 on failure
173 */
174
175 iu_timer_id_t
iu_schedule_timer(iu_tq_t * tq,uint32_t sec,iu_tq_callback_t * callback,void * arg)176 iu_schedule_timer(iu_tq_t *tq, uint32_t sec, iu_tq_callback_t *callback,
177 void *arg)
178 {
179 return (iu_schedule_timer_ms(tq, sec * MILLISEC, callback, arg));
180 }
181
182 /*
183 * iu_schedule_ms_timer(): creates and inserts a timer in the tq's timer list,
184 * using millisecond granularity
185 *
186 * input: iu_tq_t *: the timer queue
187 * uint64_t: the number of milliseconds before this timer fires
188 * iu_tq_callback_t *: the function to call when the timer fires
189 * void *: an argument to pass to the called back function
190 * output: iu_timer_id_t: the new timer's timer id on success, -1 on failure
191 */
192 iu_timer_id_t
iu_schedule_timer_ms(iu_tq_t * tq,uint64_t ms,iu_tq_callback_t * callback,void * arg)193 iu_schedule_timer_ms(iu_tq_t *tq, uint64_t ms, iu_tq_callback_t *callback,
194 void *arg)
195 {
196 iu_timer_node_t *node = calloc(1, sizeof (iu_timer_node_t));
197
198 if (node == NULL)
199 return (-1);
200
201 node->iutn_callback = callback;
202 node->iutn_arg = arg;
203 node->iutn_timer_id = get_timer_id(tq);
204 if (node->iutn_timer_id == -1) {
205 free(node);
206 return (-1);
207 }
208
209 insert_timer(tq, node, ms);
210
211 return (node->iutn_timer_id);
212 }
213
214 /*
215 * iu_cancel_timer(): cancels a pending timer from a timer queue's timer list
216 *
217 * input: iu_tq_t *: the timer queue
218 * iu_timer_id_t: the timer id returned from iu_schedule_timer
219 * void **: if non-NULL, a place to return the argument passed to
220 * iu_schedule_timer
221 * output: int: 1 on success, 0 on failure
222 */
223
224 int
iu_cancel_timer(iu_tq_t * tq,iu_timer_id_t timer_id,void ** arg)225 iu_cancel_timer(iu_tq_t *tq, iu_timer_id_t timer_id, void **arg)
226 {
227 iu_timer_node_t *node;
228
229 if (timer_id == -1)
230 return (0);
231
232 for (node = tq->iutq_head; node != NULL; node = node->iutn_next) {
233 if (node->iutn_timer_id == timer_id) {
234 if (arg != NULL)
235 *arg = node->iutn_arg;
236 remove_timer(tq, node);
237 destroy_timer(tq, node);
238 return (1);
239 }
240 }
241 return (0);
242 }
243
244 /*
245 * iu_adjust_timer(): adjusts the fire time of a timer in the tq's timer list
246 *
247 * input: iu_tq_t *: the timer queue
248 * iu_timer_id_t: the timer id returned from iu_schedule_timer
249 * uint32_t: the number of seconds before this timer fires
250 * output: int: 1 on success, 0 on failure
251 */
252
253 int
iu_adjust_timer(iu_tq_t * tq,iu_timer_id_t timer_id,uint32_t sec)254 iu_adjust_timer(iu_tq_t *tq, iu_timer_id_t timer_id, uint32_t sec)
255 {
256 iu_timer_node_t *node;
257
258 if (timer_id == -1)
259 return (0);
260
261 for (node = tq->iutq_head; node != NULL; node = node->iutn_next) {
262 if (node->iutn_timer_id == timer_id) {
263 remove_timer(tq, node);
264 insert_timer(tq, node, sec * MILLISEC);
265 return (1);
266 }
267 }
268 return (0);
269 }
270
271 /*
272 * iu_earliest_timer(): returns the time until the next timer fires on a tq
273 *
274 * input: iu_tq_t *: the timer queue
275 * output: int: the number of milliseconds until the next timer (up to
276 * a maximum value of INT_MAX), or INFTIM if no timers are pending.
277 */
278
279 int
iu_earliest_timer(iu_tq_t * tq)280 iu_earliest_timer(iu_tq_t *tq)
281 {
282 unsigned long long timeout_interval;
283 hrtime_t current_time = gethrtime();
284
285 if (tq->iutq_head == NULL)
286 return (INFTIM);
287
288 /*
289 * event might've already happened if we haven't gotten a chance to
290 * run in a while; return zero and pretend it just expired.
291 */
292
293 if (tq->iutq_head->iutn_abs_timeout <= current_time)
294 return (0);
295
296 /*
297 * since the timers are ordered in absolute time-to-fire, just
298 * subtract from the head of the list.
299 */
300
301 timeout_interval =
302 (tq->iutq_head->iutn_abs_timeout - current_time) / 1000000;
303
304 return (MIN(timeout_interval, INT_MAX));
305 }
306
307 /*
308 * iu_expire_timers(): expires all pending timers on a given timer queue
309 *
310 * input: iu_tq_t *: the timer queue
311 * output: int: the number of timers expired
312 */
313
314 int
iu_expire_timers(iu_tq_t * tq)315 iu_expire_timers(iu_tq_t *tq)
316 {
317 iu_timer_node_t *node, *next_node;
318 int n_expired = 0;
319 hrtime_t current_time = gethrtime();
320
321 /*
322 * in_expire is in the iu_tq_t instead of being passed through as
323 * an argument to remove_timer() below since the callback
324 * function may call iu_cancel_timer() itself as well.
325 */
326
327 tq->iutq_in_expire++;
328
329 /*
330 * this function builds another linked list of timer nodes
331 * through `expire_next' because the normal linked list
332 * may be changed as a result of callbacks canceling and
333 * scheduling timeouts, and thus can't be trusted.
334 */
335
336 for (node = tq->iutq_head; node != NULL; node = node->iutn_next)
337 node->iutn_expire_next = node->iutn_next;
338
339 for (node = tq->iutq_head; node != NULL;
340 node = node->iutn_expire_next) {
341
342 /*
343 * If the timeout is within 1 millisec of current time,
344 * consider it as expired already. We do this because
345 * iu_earliest_timer() only has millisec granularity.
346 * So we should also use millisec grandularity in
347 * comparing timeout values.
348 */
349 if (node->iutn_abs_timeout - current_time > 1000000)
350 break;
351
352 /*
353 * fringe condition: two timers fire at the "same
354 * time" (i.e., they're both scheduled called back in
355 * this loop) and one cancels the other. in this
356 * case, the timer which has already been "cancelled"
357 * should not be called back.
358 */
359
360 if (node->iutn_pending_delete)
361 continue;
362
363 /*
364 * we remove the timer before calling back the callback
365 * so that a callback which accidentally tries to cancel
366 * itself (through whatever means) doesn't succeed.
367 */
368
369 n_expired++;
370 remove_timer(tq, node);
371 destroy_timer(tq, node);
372 node->iutn_callback(tq, node->iutn_arg);
373 }
374
375 tq->iutq_in_expire--;
376
377 /*
378 * any cancels that took place whilst we were expiring timeouts
379 * ended up on the `pending_delete_chain'. delete them now
380 * that it's safe.
381 */
382
383 for (node = pending_delete_chain; node != NULL; node = next_node) {
384 next_node = node->iutn_next;
385 free(node);
386 }
387 pending_delete_chain = NULL;
388
389 return (n_expired);
390 }
391
392 /*
393 * get_timer_id(): allocates a timer id from the pool
394 *
395 * input: iu_tq_t *: the timer queue
396 * output: iu_timer_id_t: the allocated timer id, or -1 if none available
397 */
398
399 static iu_timer_id_t
get_timer_id(iu_tq_t * tq)400 get_timer_id(iu_tq_t *tq)
401 {
402 unsigned int map_index;
403 unsigned char map_bit;
404 boolean_t have_wrapped = B_FALSE;
405
406 for (; ; tq->iutq_next_timer_id++) {
407
408 if (tq->iutq_next_timer_id >= IU_TIMER_ID_MAX) {
409 if (have_wrapped)
410 return (-1);
411
412 have_wrapped = B_TRUE;
413 tq->iutq_next_timer_id = 0;
414 }
415
416 map_index = tq->iutq_next_timer_id / CHAR_BIT;
417 map_bit = tq->iutq_next_timer_id % CHAR_BIT;
418
419 if ((tq->iutq_timer_id_map[map_index] & (1 << map_bit)) == 0)
420 break;
421 }
422
423 tq->iutq_timer_id_map[map_index] |= (1 << map_bit);
424 return (tq->iutq_next_timer_id++);
425 }
426
427 /*
428 * release_timer_id(): releases a timer id back into the pool
429 *
430 * input: iu_tq_t *: the timer queue
431 * iu_timer_id_t: the timer id to release
432 * output: void
433 */
434
435 static void
release_timer_id(iu_tq_t * tq,iu_timer_id_t timer_id)436 release_timer_id(iu_tq_t *tq, iu_timer_id_t timer_id)
437 {
438 unsigned int map_index = timer_id / CHAR_BIT;
439 unsigned char map_bit = timer_id % CHAR_BIT;
440
441 tq->iutq_timer_id_map[map_index] &= ~(1 << map_bit);
442 }
443