/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2008 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* The interval_ routines are designed to optimize the calling of a routine
* (normally tls_multi_process()) which can be called less frequently
* between triggers.
*/
#ifndef INTERVAL_H
#define INTERVAL_H
#include "otime.h"
#define INTERVAL_DEBUG 0
/*
* Designed to limit calls to expensive functions that need to be called
* regularly.
*/
struct interval
{
interval_t refresh;
interval_t horizon;
time_t future_trigger;
time_t last_action;
time_t last_test_true;
};
void interval_init (struct interval *top, int horizon, int refresh);
/*
* IF
* last_action less than horizon seconds ago
* OR last_test_true more than refresh seconds ago
* OR hit future_trigger
* THEN
* return true
* ELSE
* set wakeup to the number of seconds until a true return
* return false
*/
static inline bool
interval_test (struct interval* top)
{
bool trigger = false;
const time_t local_now = now;
if (top->future_trigger && local_now >= top->future_trigger)
{
trigger = true;
top->future_trigger = 0;
}
if (top->last_action + top->horizon > local_now ||
top->last_test_true + top->refresh <= local_now ||
trigger)
{
top->last_test_true = local_now;
#if INTERVAL_DEBUG
dmsg (D_INTERVAL, "INTERVAL interval_test true");
#endif
return true;
}
else
{
return false;
}
}
static inline void
interval_schedule_wakeup (struct interval* top, interval_t *wakeup)
{
const time_t local_now = now;
interval_earliest_wakeup (wakeup, top->last_test_true + top->refresh, local_now);
interval_earliest_wakeup (wakeup, top->future_trigger, local_now);
#if INTERVAL_DEBUG
dmsg (D_INTERVAL, "INTERVAL interval_schedule wakeup=%d", (int)*wakeup);
#endif
}
/*
* In wakeup seconds, interval_test will return true once.
*/
static inline void
interval_future_trigger (struct interval* top, interval_t wakeup) {
if (wakeup)
{
#if INTERVAL_DEBUG
dmsg (D_INTERVAL, "INTERVAL interval_future_trigger %d", (int)wakeup);
#endif
top->future_trigger = now + wakeup;
}
}
/*
* Once an action is triggered, interval_test will remain true for
* horizon seconds.
*/
static inline void
interval_action (struct interval* top)
{
#if INTERVAL_DEBUG
dmsg (D_INTERVAL, "INTERVAL action");
#endif
top->last_action = now;
}
/*
* Measure when n seconds beyond an event have elapsed
*/
struct event_timeout
{
bool defined;
interval_t n;
time_t last; /* time of last event */
};
static inline bool
event_timeout_defined (const struct event_timeout* et)
{
return et->defined;
}
static inline void
event_timeout_clear (struct event_timeout* et)
{
et->defined = false;
et->n = 0;
et->last = 0;
}
static inline struct event_timeout
event_timeout_clear_ret ()
{
struct event_timeout ret;
event_timeout_clear (&ret);
return ret;
}
static inline void
event_timeout_init (struct event_timeout* et, interval_t n, const time_t local_now)
{
et->defined = true;
et->n = (n >= 0) ? n : 0;
et->last = local_now;
}
static inline void
event_timeout_reset (struct event_timeout* et)
{
if (et->defined)
et->last = 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)
bool event_timeout_trigger (struct event_timeout *et,
struct timeval *tv,
const int et_const_retry);
/*
* Measure time intervals in microseconds
*/
#define USEC_TIMER_MAX 60 /* maximum interval size in seconds */
#define USEC_TIMER_MAX_USEC (USEC_TIMER_MAX * 1000000)
struct usec_timer {
struct timeval start;
struct timeval end;
};
#ifdef HAVE_GETTIMEOFDAY
static inline void
usec_timer_start (struct usec_timer *obj)
{
CLEAR (*obj);
openvpn_gettimeofday (&obj->start, NULL);
}
static inline void
usec_timer_end (struct usec_timer *obj)
{
openvpn_gettimeofday (&obj->end, NULL);
}
#endif /* HAVE_GETTIMEOFDAY */
static inline bool
usec_timer_interval_defined (struct usec_timer *obj)
{
return obj->start.tv_sec && obj->end.tv_sec;
}
static inline int
usec_timer_interval (struct usec_timer *obj)
{
return tv_subtract (&obj->end, &obj->start, USEC_TIMER_MAX);
}
#endif /* INTERVAL_H */
