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// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012-2017 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
// These are our fundamental Time and Time Duration classes.
// We normally deal with time in units of 1/1024 of a second.
// This allows us to use 32-bit values to represent most time
// and time duration values, but still gives us reasonable
// accuracy. Using units of 1/1024 of a second vs. straight
// milliseconds gives us an advantage of not needing to do
// very much integer multiplication and division which can
// help us on platforms such as ARM that lack integer division
// instructions. Note that the data type used to store the time
// is an oulong, so it will automatically expand to 64 bits on
// 64-bit machines (see olong.hpp). Using a 32-bit
// data type for time durations is normally fine for clients,
// but imposes a wraparound limit of ~ 48 days. Servers
// should always use a 64-bit data type to avoid this
// limitation.
#ifndef OPENVPN_TIME_TIME_H
#define OPENVPN_TIME_TIME_H
#include <limits>
#include <cstdint> // for std::uint32_t, uint64_t
#include <openvpn/common/platform.hpp>
#include <openvpn/common/exception.hpp>
#include <openvpn/common/olong.hpp>
#include <openvpn/common/to_string.hpp>
#ifdef OPENVPN_PLATFORM_WIN
#include <time.h> // for ::time() on Windows
#include <windows.h> // for GetTickCount
#else
#include <sys/time.h> // for ::time() and ::gettimeofday()
#endif
namespace openvpn {
OPENVPN_SIMPLE_EXCEPTION(get_time_error);
template <typename T>
class TimeType
{
public:
enum { prec=1024 };
typedef ::time_t base_type;
typedef T type;
class Duration
{
friend class TimeType;
public:
static Duration seconds(const T v) { return Duration(v * prec); }
static Duration binary_ms(const T v) { return Duration(v); }
static Duration infinite() { return Duration(std::numeric_limits<T>::max()); }
static Duration milliseconds(const T v)
{
// NOTE: assumes that prec == 1024
// Also note that this might wrap if v is larger than 1/3 of max size of T
return Duration(v + (v * T(3) / T(128)));
}
Duration() noexcept : duration_(T(0)) {}
bool defined() const { return duration_ != T(0); }
bool operator!() const { return duration_ == T(0); }
bool is_infinite() const { return duration_ == std::numeric_limits<T>::max(); }
bool enabled() const { return defined() && !is_infinite(); }
void set_infinite() { duration_ = std::numeric_limits<T>::max(); }
void set_zero() { duration_ = T(0); }
Duration operator+(const Duration& d) const
{
if (is_infinite() || d.is_infinite())
return infinite();
else
return Duration(duration_ + d.duration_);
}
Duration operator+(const int delta) const
{
T duration = duration_;
if (delta >= 0)
duration += delta;
else
{
const unsigned int ndelta = -delta;
if (duration_ >= ndelta)
duration -= ndelta;
else
duration = 0;
}
return Duration(duration);
}
Duration operator*(const unsigned int mult) const
{
return Duration(duration_ * mult);
}
Duration& operator+=(const Duration& d)
{
if (is_infinite() || d.is_infinite())
set_infinite();
else
duration_ += d.duration_;
return *this;
}
void min(const Duration& d)
{
if (d.duration_ < duration_)
duration_ = d.duration_;
}
void max(const Duration& d)
{
if (d.duration_ > duration_)
duration_ = d.duration_;
}
Duration operator-(const Duration& d) const
{
if (d.duration_ >= duration_)
return Duration(0);
else if (is_infinite())
return Duration::infinite();
else
return Duration(duration_ - d.duration_);
}
Duration& operator-=(const Duration& d)
{
if (d.duration_ >= duration_)
set_zero();
else if (!is_infinite())
duration_ -= d.duration_;
return *this;
}
T to_seconds() const { return duration_ / prec; }
T to_binary_ms() const { return duration_; }
T to_milliseconds() const
{
// NOTE: assumes that prec == 1024
// Also note that this might wrap if duration_ is larger than 1/3 of max size of T
return duration_ - (duration_ * T(3) / T(128));
}
double to_double() const
{
return double(duration_) / double(prec);
}
T raw() const { return duration_; }
# define OPENVPN_DURATION_REL(OP) bool operator OP(const Duration& d) const { return duration_ OP d.duration_; }
OPENVPN_DURATION_REL(==)
OPENVPN_DURATION_REL(!=)
OPENVPN_DURATION_REL(>)
OPENVPN_DURATION_REL(<)
OPENVPN_DURATION_REL(>=)
OPENVPN_DURATION_REL(<=)
# undef OPENVPN_DURATION_REL
private:
explicit Duration(const T duration) : duration_(duration) {}
T duration_;
};
TimeType() noexcept : time_(T(0)) {}
static TimeType zero() { return TimeType(T(0)); }
static TimeType infinite() { return TimeType(std::numeric_limits<T>::max()); }
bool is_infinite() const { return time_ == std::numeric_limits<T>::max(); }
void reset() { time_ = 0; }
void set_infinite() { time_ = std::numeric_limits<T>::max(); }
bool defined() const { return time_ != 0; }
bool operator!() const { return time_ == 0; }
base_type seconds_since_epoch() const { return base_ + time_ / prec; }
T fractional_binary_ms() const { return time_ % prec; }
static TimeType now() { return TimeType(now_()); }
void update() { time_ = now_(); }
TimeType operator+(const Duration& d) const
{
if (is_infinite() || d.is_infinite())
return infinite();
else
return TimeType(time_ + d.duration_);
}
TimeType& operator+=(const Duration& d)
{
if (is_infinite() || d.is_infinite())
set_infinite();
else
time_ += d.duration_;
return *this;
}
Duration operator-(const TimeType& t) const
{
if (t.time_ >= time_)
return Duration(0);
else if (is_infinite())
return Duration::infinite();
else
return Duration(time_ - t.time_);
}
void min(const TimeType& t)
{
if (t.time_ < time_)
time_ = t.time_;
}
void max(const TimeType& t)
{
if (t.time_ > time_)
time_ = t.time_;
}
long delta_prec(const TimeType& t) const
{
return long(time_) - long(t.time_);
}
long delta(const TimeType& t) const
{
return delta_prec(t) / long(prec);
}
double delta_float(const TimeType& t) const
{
return (double(time_) - double(t.time_)) / double(prec);
}
std::string delta_str(const TimeType& t) const
{
if (!defined())
return "UNDEF-TIME";
if (is_infinite())
return "INF";
const double df = delta_float(t);
std::string ret;
if (df >= 0.0)
ret += '+';
ret += openvpn::to_string(df);
return ret;
}
# define OPENVPN_TIME_REL(OP) bool operator OP(const TimeType& t) const { return time_ OP t.time_; }
OPENVPN_TIME_REL(==)
OPENVPN_TIME_REL(!=)
OPENVPN_TIME_REL(>)
OPENVPN_TIME_REL(<)
OPENVPN_TIME_REL(>=)
OPENVPN_TIME_REL(<=)
# undef OPENVPN_TIME_REL
T raw() const { return time_; }
static void reset_base_conditional()
{
// on 32-bit systems, reset time base after 30 days
if (sizeof(T) == 4)
{
const base_type newbase = ::time(0);
if (newbase - base_ >= (60*60*24*30))
reset_base();
}
}
static void reset_base()
{
base_ = ::time(0);
#ifdef OPENVPN_PLATFORM_WIN
#if (_WIN32_WINNT >= 0x0600)
win_recalibrate((DWORD)::GetTickCount64());
#else
win_recalibrate(::GetTickCount());
#endif
#endif
}
// number of tenths of a microsecond since January 1, 1601.
static uint64_t win_time()
{
// NOTE: assumes that prec == 1024
return ((11644473600ULL * uint64_t(prec)) + (uint64_t(base_) * uint64_t(prec)) + uint64_t(now_())) * 78125ULL / 8ULL;
}
private:
explicit TimeType(const T time) : time_(time) {}
#ifdef OPENVPN_PLATFORM_WIN
static void win_recalibrate(const DWORD gtc)
{
gtc_last = gtc;
gtc_base = ::time(0) - gtc_last/1000;
}
static T now_()
{
#if (_WIN32_WINNT >= 0x0600)
const DWORD gtc = (DWORD)::GetTickCount64();
#else
const DWORD gtc = ::GetTickCount();
#endif
if (gtc < gtc_last)
win_recalibrate(gtc);
const time_t sec = gtc_base + gtc / 1000;
const unsigned int msec = gtc % 1000;
return T((sec - base_) * prec + msec * prec / 1000);
}
static DWORD gtc_last;
static time_t gtc_base;
#else
static T now_()
{
::timeval tv;
if (::gettimeofday(&tv, nullptr) != 0)
throw get_time_error();
return T((tv.tv_sec - base_) * prec + tv.tv_usec * prec / 1000000);
}
#endif
static base_type base_;
T time_;
};
#ifdef OPENVPN_PLATFORM_WIN
template <typename T> DWORD TimeType<T>::gtc_last;
template <typename T> time_t TimeType<T>::gtc_base;
#endif
template <typename T> typename TimeType<T>::base_type TimeType<T>::base_;
typedef TimeType<oulong> Time;
typedef Time* TimePtr;
} // namespace openvpn
#endif // OPENVPN_TIME_TIME_H