Fix bug #52748: the bug in timeouts.c by reimplementing timer logic to use absolute instead of relative timeout values

This commit is contained in:
Dirk Ziegelmeier 2018-01-05 11:42:14 +01:00
parent da2478b761
commit dd3861720f
2 changed files with 17 additions and 50 deletions

View File

@ -66,6 +66,9 @@
#define HANDLER(x) x #define HANDLER(x) x
#endif /* LWIP_DEBUG_TIMERNAMES */ #endif /* LWIP_DEBUG_TIMERNAMES */
/* Check if timer's expiry time is greater than time and care about u32_t wraparounds */
#define TIMER_LESS_THAN(timer, t) ( (((timer)->time == (t)) || (((u32_t)((timer)->time-(t))) > 0x7fffffff)) ? 1 : 0 )
/** This array contains all stack-internal cyclic timers. To get the number of /** This array contains all stack-internal cyclic timers. To get the number of
* timers, use LWIP_ARRAYSIZE() */ * timers, use LWIP_ARRAYSIZE() */
const struct lwip_cyclic_timer lwip_cyclic_timers[] = { const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
@ -111,7 +114,6 @@ const int lwip_num_cyclic_timers = LWIP_ARRAYSIZE(lwip_cyclic_timers);
/** The one and only timeout list */ /** The one and only timeout list */
static struct sys_timeo *next_timeout; static struct sys_timeo *next_timeout;
static u32_t timeouts_last_time;
#if LWIP_TESTMODE #if LWIP_TESTMODE
struct sys_timeo** struct sys_timeo**
@ -192,9 +194,6 @@ void sys_timeouts_init(void)
(this is OK as cyclic_timer() casts back to const* */ (this is OK as cyclic_timer() casts back to const* */
sys_timeout(lwip_cyclic_timers[i].interval_ms, cyclic_timer, LWIP_CONST_CAST(void *, &lwip_cyclic_timers[i])); sys_timeout(lwip_cyclic_timers[i].interval_ms, cyclic_timer, LWIP_CONST_CAST(void *, &lwip_cyclic_timers[i]));
} }
/* Initialise timestamp for sys_check_timeouts */
timeouts_last_time = sys_now();
} }
/** /**
@ -216,7 +215,7 @@ sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
#endif /* LWIP_DEBUG_TIMERNAMES */ #endif /* LWIP_DEBUG_TIMERNAMES */
{ {
struct sys_timeo *timeout, *t; struct sys_timeo *timeout, *t;
u32_t now, diff; u32_t now;
LWIP_ASSERT_CORE_LOCKED(); LWIP_ASSERT_CORE_LOCKED();
@ -227,17 +226,11 @@ sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
} }
now = sys_now(); now = sys_now();
if (next_timeout == NULL) {
diff = 0;
timeouts_last_time = now;
} else {
diff = now - timeouts_last_time;
}
timeout->next = NULL; timeout->next = NULL;
timeout->h = handler; timeout->h = handler;
timeout->arg = arg; timeout->arg = arg;
timeout->time = msecs + diff; timeout->time = (u32_t)(now + msecs); /* overflow handled by TIMER_LESS_THAN macro */
#if LWIP_DEBUG_TIMERNAMES #if LWIP_DEBUG_TIMERNAMES
timeout->handler_name = handler_name; timeout->handler_name = handler_name;
LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n", LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%"U32_F" handler=%s arg=%p\n",
@ -248,24 +241,12 @@ sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
next_timeout = timeout; next_timeout = timeout;
return; return;
} }
if (TIMER_LESS_THAN(timeout, next_timeout->time)) {
if (next_timeout->time > msecs) {
next_timeout->time -= msecs;
timeout->next = next_timeout; timeout->next = next_timeout;
next_timeout = timeout; next_timeout = timeout;
} else { } else {
for (t = next_timeout; t != NULL; t = t->next) { for (t = next_timeout; t != NULL; t = t->next) {
timeout->time -= t->time; if ((t->next == NULL) || TIMER_LESS_THAN(timeout, t->next->time)) {
if (t->next == NULL || t->next->time > timeout->time) {
if (t->next != NULL) {
t->next->time -= timeout->time;
} else if (timeout->time > msecs) {
/* If this is the case, 'timeouts_last_time' and 'now' differs too much.
This can be due to sys_check_timeouts() not being called at the right
times, but also when stopping in a breakpoint. Anyway, let's assume
this is not wanted, so add the first timer's time instead of 'diff' */
timeout->time = msecs + next_timeout->time;
}
timeout->next = t->next; timeout->next = t->next;
t->next = timeout; t->next = timeout;
break; break;
@ -331,24 +312,19 @@ sys_check_timeouts(void)
if (next_timeout) { if (next_timeout) {
struct sys_timeo *tmptimeout; struct sys_timeo *tmptimeout;
u32_t diff;
sys_timeout_handler handler; sys_timeout_handler handler;
void *arg; void *arg;
u8_t had_one; u8_t had_one;
u32_t now; u32_t now;
now = sys_now(); now = sys_now();
/* this cares for wraparounds */
diff = now - timeouts_last_time;
do { do {
PBUF_CHECK_FREE_OOSEQ(); PBUF_CHECK_FREE_OOSEQ();
had_one = 0; had_one = 0;
tmptimeout = next_timeout; tmptimeout = next_timeout;
if (tmptimeout && (tmptimeout->time <= diff)) { if (tmptimeout && TIMER_LESS_THAN(tmptimeout, now)) {
/* timeout has expired */ /* timeout has expired */
had_one = 1; had_one = 1;
timeouts_last_time += tmptimeout->time;
diff -= tmptimeout->time;
next_timeout = tmptimeout->next; next_timeout = tmptimeout->next;
handler = tmptimeout->h; handler = tmptimeout->h;
arg = tmptimeout->arg; arg = tmptimeout->arg;
@ -369,17 +345,12 @@ sys_check_timeouts(void)
} }
} }
/** Set back the timestamp of the last call to sys_check_timeouts() /**
* This is necessary if sys_check_timeouts() hasn't been called for a long * @deprecated Just delete your call to this function
* time (e.g. while saving energy) to prevent all timer functions of that
* period being called.
*/ */
void void
sys_restart_timeouts(void) sys_restart_timeouts(void)
{ {
LWIP_ASSERT_CORE_LOCKED();
timeouts_last_time = sys_now();
} }
/** Return the time left before the next timeout is due. If no timeouts are /** Return the time left before the next timeout is due. If no timeouts are
@ -391,18 +362,18 @@ static
u32_t u32_t
sys_timeouts_sleeptime(void) sys_timeouts_sleeptime(void)
{ {
u32_t diff; u32_t now;
LWIP_ASSERT_CORE_LOCKED(); LWIP_ASSERT_CORE_LOCKED();
if (next_timeout == NULL) { if (next_timeout == NULL) {
return 0xffffffff; return 0xffffffff;
} }
diff = sys_now() - timeouts_last_time; now = sys_now();
if (diff > next_timeout->time) { if (TIMER_LESS_THAN(next_timeout, now)) {
return 0; return 0;
} else { } else {
return next_timeout->time - diff; return (u32_t)(next_timeout->time - now);
} }
} }

View File

@ -65,9 +65,9 @@ END_TEST
START_TEST(test_timers) START_TEST(test_timers)
{ {
LWIP_UNUSED_ARG(_i); struct sys_timeo** list_head = lwip_sys_timers_get_next_timout();
/* struct sys_timeo** list_head = lwip_sys_timers_get_next_timout(); */ LWIP_UNUSED_ARG(_i);
/* check without u32_t wraparound */ /* check without u32_t wraparound */
@ -81,11 +81,9 @@ START_TEST(test_timers)
fail_unless(sys_timeouts_sleeptime() == 5); fail_unless(sys_timeouts_sleeptime() == 5);
/* linked list correctly sorted? */ /* linked list correctly sorted? */
/*
fail_unless((*list_head)->time == (u32_t)(lwip_sys_now + 5)); fail_unless((*list_head)->time == (u32_t)(lwip_sys_now + 5));
fail_unless((*list_head)->next->time == (u32_t)(lwip_sys_now + 10)); fail_unless((*list_head)->next->time == (u32_t)(lwip_sys_now + 10));
fail_unless((*list_head)->next->next->time == (u32_t)(lwip_sys_now + 20)); fail_unless((*list_head)->next->next->time == (u32_t)(lwip_sys_now + 20));
*/
/* check timers expire in correct order */ /* check timers expire in correct order */
memset(&fired, 0, sizeof(fired)); memset(&fired, 0, sizeof(fired));
@ -130,11 +128,9 @@ START_TEST(test_timers)
fail_unless(sys_timeouts_sleeptime() == 5); fail_unless(sys_timeouts_sleeptime() == 5);
/* linked list correctly sorted? */ /* linked list correctly sorted? */
/*
fail_unless((*list_head)->time == (u32_t)(lwip_sys_now + 5)); fail_unless((*list_head)->time == (u32_t)(lwip_sys_now + 5));
fail_unless((*list_head)->next->time == (u32_t)(lwip_sys_now + 10)); fail_unless((*list_head)->next->time == (u32_t)(lwip_sys_now + 10));
fail_unless((*list_head)->next->next->time == (u32_t)(lwip_sys_now + 20)); fail_unless((*list_head)->next->next->time == (u32_t)(lwip_sys_now + 20));
*/
/* check timers expire in correct order */ /* check timers expire in correct order */
memset(&fired, 0, sizeof(fired)); memset(&fired, 0, sizeof(fired));
@ -174,7 +170,7 @@ Suite *
timers_suite(void) timers_suite(void)
{ {
testfunc tests[] = { testfunc tests[] = {
/* TESTFUNC(test_bug52748), */ TESTFUNC(test_bug52748),
TESTFUNC(test_timers) TESTFUNC(test_timers)
}; };
testfunc tests_unused[] = { testfunc tests_unused[] = {