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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2021 OpenVPN 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
#ifndef HAVE_GETTIMEOFDAY
#include "compat.h"
#ifdef _WIN32
/*
* NOTICE: mingw has much faster gettimeofday!
* autoconf will set HAVE_GETTIMEOFDAY
*/
#include <windows.h>
#include <time.h>
static time_t gtc_base = 0;
static DWORD gtc_last = 0;
static time_t last_sec = 0;
static unsigned int last_msec = 0;
static int bt_last = 0;
static void
gettimeofday_calibrate(void)
{
const time_t t = time(NULL);
const DWORD gtc = GetTickCount();
gtc_base = t - gtc/1000;
gtc_last = gtc;
}
/*
* Rewritten by JY for OpenVPN 2.1, after I realized that
* QueryPerformanceCounter takes nearly 2 orders of magnitude
* more processor cycles than GetTickCount.
*/
int
gettimeofday(struct timeval *tv, void *tz)
{
const DWORD gtc = GetTickCount();
int bt = 0;
time_t sec;
unsigned int msec;
const int backtrack_hold_seconds = 10;
(void)tz;
/* recalibrate at the dreaded 49.7 day mark */
if (!gtc_base || gtc < gtc_last)
{
gettimeofday_calibrate();
}
gtc_last = gtc;
sec = gtc_base + gtc / 1000;
msec = gtc % 1000;
if (sec == last_sec)
{
if (msec < last_msec)
{
msec = last_msec;
bt = 1;
}
}
else if (sec < last_sec)
{
/* We try to dampen out backtracks of less than backtrack_hold_seconds.
* Larger backtracks will be passed through and dealt with by the
* TIME_BACKTRACK_PROTECTION code (if enabled) */
if (sec > last_sec - backtrack_hold_seconds)
{
sec = last_sec;
msec = last_msec;
}
bt = 1;
}
tv->tv_sec = (long)last_sec = (long)sec;
tv->tv_usec = (last_msec = msec) * 1000;
if (bt && !bt_last)
{
gettimeofday_calibrate();
}
bt_last = bt;
return 0;
}
#else /* ifdef _WIN32 */
#ifdef HAVE_TIME_H
#include <time.h>
#endif
int
gettimeofday(struct timeval *tv, void *tz)
{
(void)tz;
tv->tv_sec = time(NULL);
tv->tv_usec = 0;
return 0;
}
#endif /* _WIN32 */
#endif /* HAVE_GETTIMEOFDAY */
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