1/**
2 * @file
3 * Stack-internal timers implementation.
4 * This file includes timer callbacks for stack-internal timers as well as
5 * functions to set up or stop timers and check for expired timers.
6 *
7 */
8
9/*
10 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without modification,
14 * are permitted provided that the following conditions are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright notice,
17 *    this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright notice,
19 *    this list of conditions and the following disclaimer in the documentation
20 *    and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote products
22 *    derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
33 * OF SUCH DAMAGE.
34 *
35 * This file is part of the lwIP TCP/IP stack.
36 *
37 * Author: Adam Dunkels <adam@sics.se>
38 *         Simon Goldschmidt
39 *
40 */
41
42#include "lwip/opt.h"
43
44#include "lwip/timeouts.h"
45#include "lwip/priv/tcp_priv.h"
46
47#include "lwip/def.h"
48#include "lwip/memp.h"
49#include "lwip/priv/tcpip_priv.h"
50
51#include "lwip/ip4_frag.h"
52#include "lwip/etharp.h"
53#include "lwip/dhcp.h"
54#include "lwip/autoip.h"
55#include "lwip/igmp.h"
56#include "lwip/dns.h"
57#include "lwip/nd6.h"
58#include "lwip/ip6_frag.h"
59#include "lwip/mld6.h"
60#include "lwip/sys.h"
61#include "lwip/pbuf.h"
62
63#if LWIP_DEBUG_TIMERNAMES
64#define HANDLER(x) x, #x
65#else /* LWIP_DEBUG_TIMERNAMES */
66#define HANDLER(x) x
67#endif /* LWIP_DEBUG_TIMERNAMES */
68
69/** This array contains all stack-internal cyclic timers. To get the number of
70 * timers, use LWIP_ARRAYSIZE() */
71const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
72#if LWIP_TCP
73  /* The TCP timer is a special case: it does not have to run always and
74     is triggered to start from TCP using tcp_timer_needed() */
75  {TCP_TMR_INTERVAL, HANDLER(tcp_tmr)},
76#endif /* LWIP_TCP */
77#if LWIP_IPV4
78#if IP_REASSEMBLY
79  {IP_TMR_INTERVAL, HANDLER(ip_reass_tmr)},
80#endif /* IP_REASSEMBLY */
81#if LWIP_ARP
82  {ARP_TMR_INTERVAL, HANDLER(etharp_tmr)},
83#endif /* LWIP_ARP */
84#if LWIP_DHCP
85  {DHCP_COARSE_TIMER_MSECS, HANDLER(dhcp_coarse_tmr)},
86  {DHCP_FINE_TIMER_MSECS, HANDLER(dhcp_fine_tmr)},
87#endif /* LWIP_DHCP */
88#if LWIP_AUTOIP
89  {AUTOIP_TMR_INTERVAL, HANDLER(autoip_tmr)},
90#endif /* LWIP_AUTOIP */
91#if LWIP_IGMP
92  {IGMP_TMR_INTERVAL, HANDLER(igmp_tmr)},
93#endif /* LWIP_IGMP */
94#endif /* LWIP_IPV4 */
95#if LWIP_DNS
96  {DNS_TMR_INTERVAL, HANDLER(dns_tmr)},
97#endif /* LWIP_DNS */
98#if LWIP_IPV6
99  {ND6_TMR_INTERVAL, HANDLER(nd6_tmr)},
100#if LWIP_IPV6_REASS
101  {IP6_REASS_TMR_INTERVAL, HANDLER(ip6_reass_tmr)},
102#endif /* LWIP_IPV6_REASS */
103#if LWIP_IPV6_MLD
104  {MLD6_TMR_INTERVAL, HANDLER(mld6_tmr)},
105#endif /* LWIP_IPV6_MLD */
106#endif /* LWIP_IPV6 */
107};
108
109#if LWIP_TIMERS && !LWIP_TIMERS_CUSTOM
110
111/** The one and only timeout list */
112static struct sys_timeo *next_timeout;
113static u32_t timeouts_last_time;
114
115#if LWIP_TCP
116/** global variable that shows if the tcp timer is currently scheduled or not */
117static int tcpip_tcp_timer_active;
118
119/**
120 * Timer callback function that calls tcp_tmr() and reschedules itself.
121 *
122 * @param arg unused argument
123 */
124static void
125tcpip_tcp_timer(void *arg)
126{
127  LWIP_UNUSED_ARG(arg);
128
129  /* call TCP timer handler */
130  tcp_tmr();
131  /* timer still needed? */
132  if (tcp_active_pcbs || tcp_tw_pcbs) {
133    /* restart timer */
134    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
135  } else {
136    /* disable timer */
137    tcpip_tcp_timer_active = 0;
138  }
139}
140
141/**
142 * Called from TCP_REG when registering a new PCB:
143 * the reason is to have the TCP timer only running when
144 * there are active (or time-wait) PCBs.
145 */
146void
147tcp_timer_needed(void)
148{
149  /* timer is off but needed again? */
150  if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
151    /* enable and start timer */
152    tcpip_tcp_timer_active = 1;
153    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
154  }
155}
156#endif /* LWIP_TCP */
157
158/**
159 * Timer callback function that calls mld6_tmr() and reschedules itself.
160 *
161 * @param arg unused argument
162 */
163static void
164cyclic_timer(void *arg)
165{
166  const struct lwip_cyclic_timer* cyclic = (const struct lwip_cyclic_timer*)arg;
167#if LWIP_DEBUG_TIMERNAMES
168  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: %s()\n", cyclic->handler_name));
169#endif
170  cyclic->handler();
171  sys_timeout(cyclic->interval_ms, cyclic_timer, arg);
172}
173
174/** Initialize this module */
175void sys_timeouts_init(void)
176{
177  size_t i;
178  /* tcp_tmr() at index 0 is started on demand */
179  for (i = 1; i < LWIP_ARRAYSIZE(lwip_cyclic_timers); i++) {
180    /* we have to cast via size_t to get rid of const warning
181      (this is OK as cyclic_timer() casts back to const* */
182    sys_timeout(lwip_cyclic_timers[i].interval_ms, cyclic_timer, LWIP_CONST_CAST(void*, &lwip_cyclic_timers[i]));
183  }
184
185  /* Initialise timestamp for sys_check_timeouts */
186  timeouts_last_time = sys_now();
187}
188
189/**
190 * Create a one-shot timer (aka timeout). Timeouts are processed in the
191 * following cases:
192 * - while waiting for a message using sys_timeouts_mbox_fetch()
193 * - by calling sys_check_timeouts() (NO_SYS==1 only)
194 *
195 * @param msecs time in milliseconds after that the timer should expire
196 * @param handler callback function to call when msecs have elapsed
197 * @param arg argument to pass to the callback function
198 */
199#if LWIP_DEBUG_TIMERNAMES
200void
201sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name)
202#else /* LWIP_DEBUG_TIMERNAMES */
203void
204sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
205#endif /* LWIP_DEBUG_TIMERNAMES */
206{
207  struct sys_timeo *timeout, *t;
208  u32_t now, diff;
209
210  timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
211  if (timeout == NULL) {
212    LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
213    return;
214  }
215
216  now = sys_now();
217  if (next_timeout == NULL) {
218    diff = 0;
219    timeouts_last_time = now;
220  } else {
221    diff = now - timeouts_last_time;
222  }
223
224  timeout->next = NULL;
225  timeout->h = handler;
226  timeout->arg = arg;
227  timeout->time = msecs + diff;
228#if LWIP_DEBUG_TIMERNAMES
229  timeout->handler_name = handler_name;
230  LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n",
231    (void *)timeout, msecs, handler_name, (void *)arg));
232#endif /* LWIP_DEBUG_TIMERNAMES */
233
234  if (next_timeout == NULL) {
235    next_timeout = timeout;
236    return;
237  }
238
239  if (next_timeout->time > msecs) {
240    next_timeout->time -= msecs;
241    timeout->next = next_timeout;
242    next_timeout = timeout;
243  } else {
244    for (t = next_timeout; t != NULL; t = t->next) {
245      timeout->time -= t->time;
246      if (t->next == NULL || t->next->time > timeout->time) {
247        if (t->next != NULL) {
248          t->next->time -= timeout->time;
249        } else if (timeout->time > msecs) {
250          /* If this is the case, 'timeouts_last_time' and 'now' differs too much.
251             This can be due to sys_check_timeouts() not being called at the right
252             times, but also when stopping in a breakpoint. Anyway, let's assume
253             this is not wanted, so add the first timer's time instead of 'diff' */
254          timeout->time = msecs + next_timeout->time;
255        }
256        timeout->next = t->next;
257        t->next = timeout;
258        break;
259      }
260    }
261  }
262}
263
264/**
265 * Go through timeout list (for this task only) and remove the first matching
266 * entry (subsequent entries remain untouched), even though the timeout has not
267 * triggered yet.
268 *
269 * @param handler callback function that would be called by the timeout
270 * @param arg callback argument that would be passed to handler
271*/
272void
273sys_untimeout(sys_timeout_handler handler, void *arg)
274{
275  struct sys_timeo *prev_t, *t;
276
277  if (next_timeout == NULL) {
278    return;
279  }
280
281  for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
282    if ((t->h == handler) && (t->arg == arg)) {
283      /* We have a match */
284      /* Unlink from previous in list */
285      if (prev_t == NULL) {
286        next_timeout = t->next;
287      } else {
288        prev_t->next = t->next;
289      }
290      /* If not the last one, add time of this one back to next */
291      if (t->next != NULL) {
292        t->next->time += t->time;
293      }
294      memp_free(MEMP_SYS_TIMEOUT, t);
295      return;
296    }
297  }
298  return;
299}
300
301/**
302 * @ingroup lwip_nosys
303 * Handle timeouts for NO_SYS==1 (i.e. without using
304 * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
305 * handler functions when timeouts expire.
306 *
307 * Must be called periodically from your main loop.
308 */
309#if !NO_SYS && !defined __DOXYGEN__
310static
311#endif /* !NO_SYS */
312void
313sys_check_timeouts(void)
314{
315  if (next_timeout) {
316    struct sys_timeo *tmptimeout;
317    u32_t diff;
318    sys_timeout_handler handler;
319    void *arg;
320    u8_t had_one;
321    u32_t now;
322
323    now = sys_now();
324    /* this cares for wraparounds */
325    diff = now - timeouts_last_time;
326    do {
327      PBUF_CHECK_FREE_OOSEQ();
328      had_one = 0;
329      tmptimeout = next_timeout;
330      if (tmptimeout && (tmptimeout->time <= diff)) {
331        /* timeout has expired */
332        had_one = 1;
333        timeouts_last_time += tmptimeout->time;
334        diff -= tmptimeout->time;
335        next_timeout = tmptimeout->next;
336        handler = tmptimeout->h;
337        arg = tmptimeout->arg;
338#if LWIP_DEBUG_TIMERNAMES
339        if (handler != NULL) {
340          LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n",
341            tmptimeout->handler_name, arg));
342        }
343#endif /* LWIP_DEBUG_TIMERNAMES */
344        memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
345        if (handler != NULL) {
346#if !NO_SYS
347          /* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the
348             timeout handler function. */
349          LOCK_TCPIP_CORE();
350#endif /* !NO_SYS */
351          handler(arg);
352#if !NO_SYS
353          UNLOCK_TCPIP_CORE();
354#endif /* !NO_SYS */
355        }
356        LWIP_TCPIP_THREAD_ALIVE();
357      }
358    /* repeat until all expired timers have been called */
359    } while (had_one);
360  }
361}
362
363/** Set back the timestamp of the last call to sys_check_timeouts()
364 * This is necessary if sys_check_timeouts() hasn't been called for a long
365 * time (e.g. while saving energy) to prevent all timer functions of that
366 * period being called.
367 */
368void
369sys_restart_timeouts(void)
370{
371  timeouts_last_time = sys_now();
372}
373
374/** Return the time left before the next timeout is due. If no timeouts are
375 * enqueued, returns 0xffffffff
376 */
377#if !NO_SYS
378static
379#endif /* !NO_SYS */
380u32_t
381sys_timeouts_sleeptime(void)
382{
383  u32_t diff;
384  if (next_timeout == NULL) {
385    return 0xffffffff;
386  }
387  diff = sys_now() - timeouts_last_time;
388  if (diff > next_timeout->time) {
389    return 0;
390  } else {
391    return next_timeout->time - diff;
392  }
393}
394
395#if !NO_SYS
396
397/**
398 * Wait (forever) for a message to arrive in an mbox.
399 * While waiting, timeouts are processed.
400 *
401 * @param mbox the mbox to fetch the message from
402 * @param msg the place to store the message
403 */
404void
405sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg)
406{
407  u32_t sleeptime;
408
409again:
410  if (!next_timeout) {
411    sys_arch_mbox_fetch(mbox, msg, 0);
412    return;
413  }
414
415  sleeptime = sys_timeouts_sleeptime();
416  if (sleeptime == 0 || sys_arch_mbox_fetch(mbox, msg, sleeptime) == SYS_ARCH_TIMEOUT) {
417    /* If a SYS_ARCH_TIMEOUT value is returned, a timeout occurred
418       before a message could be fetched. */
419    sys_check_timeouts();
420    /* We try again to fetch a message from the mbox. */
421    goto again;
422  }
423}
424
425#endif /* NO_SYS */
426
427#else /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */
428/* Satisfy the TCP code which calls this function */
429void
430tcp_timer_needed(void)
431{
432}
433#endif /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */
434