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Document/cleanup event_timeout functions

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Remove function event_timeout_clear_ret as it is unused.

Cleanup event_timeout_trigger a bit. Do an instant return false if the
timeout is not defined and inline local_now and use
event_timeout_remaining instead of local duplicated code.

Add doxygen comments for all timeout function, especially for the
event_timeout_trigger function that is hard to understand otherwise.

Patch v2: add many fixes/correction suggested by Frank

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20221006122940.1202712-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg25348.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
This commit is contained in:
Arne Schwabe 2022-10-06 14:29:40 +02:00 committed by Gert Doering
parent 437812d4ea
commit 0b980fa4e5
3 changed files with 105 additions and 59 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

57
src/openvpn/interval.c
View file

@ -46,39 +46,40 @@ event_timeout_trigger(struct event_timeout *et,
struct timeval *tv,
const int et_const_retry)
{
bool ret = false;
const time_t local_now = now;
if (et->defined)
if (!et->defined)
{
time_t wakeup = et->last - local_now + et->n;
if (wakeup <= 0)
{
#if INTERVAL_DEBUG
dmsg(D_INTERVAL, "EVENT event_timeout_trigger (%d) etcr=%d", et->n,
et_const_retry);
#endif
if (et_const_retry < 0)
{
et->last = local_now;
wakeup = et->n;
ret = true;
}
else
{
wakeup = et_const_retry;
}
}
return false;
}
if (tv && wakeup < tv->tv_sec)
{
bool ret = false;
time_t wakeup = event_timeout_remaining(et);
if (wakeup <= 0)
{
#if INTERVAL_DEBUG
dmsg(D_INTERVAL, "EVENT event_timeout_wakeup (%d/%d) etcr=%d",
(int) wakeup, et->n, et_const_retry);
dmsg(D_INTERVAL, "EVENT event_timeout_trigger (%d) etcr=%d", et->n,
et_const_retry);
#endif
tv->tv_sec = wakeup;
tv->tv_usec = 0;
if (et_const_retry < 0)
{
et->last = now;
wakeup = et->n;
ret = true;
}
else
{
wakeup = et_const_retry;
}
}
if (tv && wakeup < tv->tv_sec)
{
#if INTERVAL_DEBUG
dmsg(D_INTERVAL, "EVENT event_timeout_wakeup (%d/%d) etcr=%d",
(int) wakeup, et->n, et_const_retry);
#endif
tv->tv_sec = wakeup;
tv->tv_usec = 0;
}
return ret;
}

103
src/openvpn/interval.h
View file

@ -135,9 +135,9 @@ interval_action(struct interval *top)
struct event_timeout
{
bool defined;
interval_t n;
time_t last; /* time of last event */
bool defined; /**< This timeout is active */
interval_t n; /**< periodic interval for periodic timeouts */
time_t last; /**< time of last event */
};
static inline bool
@ -145,7 +145,12 @@ event_timeout_defined(const struct event_timeout *et)
{
return et->defined;
}
/**
* Clears the timeout and reset all values to 0. Following timer checks will
* not trigger.
*
* @param et timer struct
*/
static inline void
event_timeout_clear(struct event_timeout *et)
{
@ -154,22 +159,32 @@ event_timeout_clear(struct event_timeout *et)
et->last = 0;
}
static inline struct event_timeout
event_timeout_clear_ret(void)
{
struct event_timeout ret;
event_timeout_clear(&ret);
return ret;
}
/**
* Initialises a timer struct. The timer will become true/trigger after
* last + n seconds.
*
*
* @param et Timer struct
* @param n Interval of the timer for periodic timer. A negative
* value for n will be interpreted as 0.
* @param last Sets the base time of the timer.
*/
static inline void
event_timeout_init(struct event_timeout *et, interval_t n, const time_t local_now)
event_timeout_init(struct event_timeout *et, interval_t n, const time_t last)
{
et->defined = true;
et->n = (n >= 0) ? n : 0;
et->last = local_now;
et->last = last;
}
/**
* Resets a timer.
*
* Sets the last time the timer has been triggered for the calculation of the
* next event.
* @param et
*/
static inline void
event_timeout_reset(struct event_timeout *et)
{
@ -179,42 +194,70 @@ event_timeout_reset(struct event_timeout *et)
}
}
/**
* Sets the interval n of a timeout.
* @param et
* @param n Interval value of the timer, negative values
* will be interpreted as 0
*
* @note you might need to call reset_coarse_timers after this
*/
static inline void
event_timeout_modify_wakeup(struct event_timeout *et, interval_t n)
{
/* note that you might need to call reset_coarse_timers after this */
if (et->defined)
{
et->n = (n >= 0) ? n : 0;
}
}
/*
* Will return the time left for a timeout, this function does not check
* if the timeout is actually valid
/**
* Returns the time until the timeout should triggered, from \c now.
* This function does not check if the timeout is actually valid.
*/
static inline interval_t
event_timeout_remaining(struct event_timeout *et)
{
return (interval_t) (et->last - now + et->n);
return (interval_t) ((et->last + et->n) - now);
}
/*
* This is the principal function for testing and triggering recurring
* timers and will return true on a timer signal event.
* If et_const_retry == ETT_DEFAULT and a signal occurs,
* the function will return true and *et will be armed for the
* next event. If et_const_retry >= 0 and a signal occurs,
* *et will not be touched, but *tv will be set to
* minimum (*tv, et_const_retry) for a future re-test,
* and the function will return true.
*/
#define ETT_DEFAULT (-1)
/**
* This is the principal function for testing and triggering recurring
* timers.
*
* If *et is not triggered, *tv is set to remaining time until the timeout if
* not already lower:
*
* *tv = minimum(*tv, event_timeout_remaining(*et))
*
* If *et triggers and et_const_retry is negative (ETT_DEFAULT is -1):
* - the function will return true
* - *et will be armed for the next event (et->last set to now).
* - *tv will be lowered to the event period (n) if larger than the
* period of the event (set to *et's next timeout)
* - *et will not changed (ie also not rearmed, stays armed)
*
* If *et triggers and et_const_retry >= 0, *tv will be lowered to et_const_try
* if larger:
*
* *tv = *minimum(*tv, et_const_retry)
*
* This is mainly useful if the trigger cannot yet be triggered for other
* reasons and a backoff timeout should be returned if the timer is ready
* to trigger.
*
*
* @param et the timeout to check
* @param tv will be set to timeout for next check for this
* timeout unless already smaller.
* @param et_const_retry see above
* @return if the timeout has triggered and event has been reset
*/
bool event_timeout_trigger(struct event_timeout *et,
struct timeval *tv,
const int et_const_retry);
int et_const_retry);
/*
* Measure time intervals in microseconds

4
src/openvpn/openvpn.h
View file

@ -386,7 +386,9 @@ struct context_2
* Event loop info
*/
/* how long to wait on link/tun read before we will need to be serviced */
/** Time to next event of timers and similar. This is used to determine
* how long to wait on event wait (select/poll on link/tun read)
* before this context wants to be serviced. */
struct timeval timeval;
/* next wakeup for processing coarse timers (>1 sec resolution) */