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/*
* 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) 2002-2017 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; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif
#include "syshead.h"
#include "otime.h"
#include "memdbg.h"
time_t now = 0; /* GLOBAL */
#if TIME_BACKTRACK_PROTECTION
static time_t now_adj = 0; /* GLOBAL */
time_t now_usec = 0; /* GLOBAL */
/*
* Try to filter out time instability caused by the system
* clock backtracking or jumping forward.
*/
void
update_now(const time_t system_time)
{
const int forward_threshold = 86400; /* threshold at which to dampen forward jumps */
const int backward_trigger = 10; /* backward jump must be >= this many seconds before we adjust */
time_t real_time = system_time + now_adj;
if (real_time > now)
{
const time_t overshoot = real_time - now - 1;
if (overshoot > forward_threshold && now_adj >= overshoot)
{
now_adj -= overshoot;
real_time -= overshoot;
}
now = real_time;
}
else if (real_time < now - backward_trigger)
{
now_adj += (now - real_time);
}
}
void
update_now_usec(struct timeval *tv)
{
const time_t last = now;
update_now(tv->tv_sec);
if (now > last || (now == last && tv->tv_usec > now_usec))
{
now_usec = tv->tv_usec;
}
}
#endif /* TIME_BACKTRACK_PROTECTION */
/*
* Return a numerical string describing a struct timeval.
*/
const char *
tv_string(const struct timeval *tv, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(64, gc);
buf_printf(&out, "[%d/%d]",
(int) tv->tv_sec,
(int )tv->tv_usec);
return BSTR(&out);
}
/*
* Return an ascii string describing an absolute
* date/time in a struct timeval.
*
*/
const char *
tv_string_abs(const struct timeval *tv, struct gc_arena *gc)
{
return time_string((time_t) tv->tv_sec,
(int) tv->tv_usec,
true,
gc);
}
/* format a time_t as ascii, or use current time if 0 */
const char *
time_string(time_t t, int usec, bool show_usec, struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc(64, gc);
struct timeval tv;
if (t)
{
tv.tv_sec = t;
tv.tv_usec = usec;
}
else
{
gettimeofday(&tv, NULL);
}
t = tv.tv_sec;
buf_printf(&out, "%s", ctime(&t));
buf_rmtail(&out, '\n');
if (show_usec && tv.tv_usec)
{
buf_printf(&out, " us=%d", (int)tv.tv_usec);
}
return BSTR(&out);
}
/*
* Limit the frequency of an event stream.
*
* Used to control maximum rate of new
* incoming connections.
*/
struct frequency_limit *
frequency_limit_init(int max, int per)
{
struct frequency_limit *f;
ASSERT(max >= 0 && per >= 0);
ALLOC_OBJ(f, struct frequency_limit);
f->max = max;
f->per = per;
f->n = 0;
f->reset = 0;
return f;
}
void
frequency_limit_free(struct frequency_limit *f)
{
free(f);
}
bool
frequency_limit_event_allowed(struct frequency_limit *f)
{
if (f->per)
{
bool ret;
if (now >= f->reset + f->per)
{
f->reset = now;
f->n = 0;
}
ret = (++f->n <= f->max);
return ret;
}
else
{
return true;
}
}
#ifdef TIME_TEST
void
time_test(void)
{
struct timeval tv;
time_t t;
int i;
for (i = 0; i < 10000; ++i)
{
t = time(NULL);
gettimeofday(&tv, NULL);
#if 1
msg(M_INFO, "t=%u s=%u us=%u",
(unsigned int)t,
(unsigned int)tv.tv_sec,
(unsigned int)tv.tv_usec);
#endif
}
}
#endif
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