aboutsummaryrefslogtreecommitdiff
path: root/interval.h
blob: f0e5875fb0e370d810f8a196686aae4eec7c2fc3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
/*
 *  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) 2002-2009 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;
}

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;
}

/*
 * 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 */