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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.
*/
#ifndef SHAPER_H
#define SHAPER_H
/*#define SHAPER_DEBUG*/
#ifdef ENABLE_FEATURE_SHAPER
#include "basic.h"
#include "integer.h"
#include "misc.h"
#include "error.h"
#include "interval.h"
/*
* A simple traffic shaper for
* the output direction.
*/
#define SHAPER_MIN 100 /* bytes per second */
#define SHAPER_MAX 100000000
#define SHAPER_MAX_TIMEOUT 10 /* seconds */
#define SHAPER_USE_FP
struct shaper
{
int bytes_per_second;
struct timeval wakeup;
#ifdef SHAPER_USE_FP
double factor;
#else
int factor;
#endif
};
void shaper_msg(struct shaper *s);
void shaper_reset_wakeup(struct shaper *s);
/*
* We want to wake up in delay microseconds. If timeval is larger
* than delay, set timeval to delay.
*/
bool shaper_soonest_event(struct timeval *tv, int delay);
/*
* inline functions
*/
static inline void
shaper_reset(struct shaper *s, int bytes_per_second)
{
s->bytes_per_second = constrain_int(bytes_per_second, SHAPER_MIN, SHAPER_MAX);
#ifdef SHAPER_USE_FP
s->factor = 1000000.0 / (double)s->bytes_per_second;
#else
s->factor = 1000000 / s->bytes_per_second;
#endif
}
static inline void
shaper_init(struct shaper *s, int bytes_per_second)
{
shaper_reset(s, bytes_per_second);
shaper_reset_wakeup(s);
}
static inline int
shaper_current_bandwidth(struct shaper *s)
{
return s->bytes_per_second;
}
/*
* Returns traffic shaping delay in microseconds relative to current
* time, or 0 if no delay.
*/
static inline int
shaper_delay(struct shaper *s)
{
struct timeval tv;
int delay = 0;
if (tv_defined(&s->wakeup))
{
ASSERT(!openvpn_gettimeofday(&tv, NULL));
delay = tv_subtract(&s->wakeup, &tv, SHAPER_MAX_TIMEOUT);
#ifdef SHAPER_DEBUG
dmsg(D_SHAPER_DEBUG, "SHAPER shaper_delay delay=%d", delay);
#endif
}
return delay > 0 ? delay : 0;
}
/*
* We are about to send a datagram of nbytes bytes.
*
* Compute when we can send another datagram,
* based on target throughput (s->bytes_per_second).
*/
static inline void
shaper_wrote_bytes(struct shaper *s, int nbytes)
{
struct timeval tv;
/* compute delay in microseconds */
tv.tv_sec = 0;
#ifdef SHAPER_USE_FP
tv.tv_usec = min_int((int)((double)max_int(nbytes, 100) * s->factor), (SHAPER_MAX_TIMEOUT*1000000));
#else
tv.tv_usec = s->bytes_per_second
? min_int(max_int(nbytes, 100) * s->factor, (SHAPER_MAX_TIMEOUT*1000000))
: 0;
#endif
if (tv.tv_usec)
{
ASSERT(!openvpn_gettimeofday(&s->wakeup, NULL));
tv_add(&s->wakeup, &tv);
#ifdef SHAPER_DEBUG
dmsg(D_SHAPER_DEBUG, "SHAPER shaper_wrote_bytes bytes=%d delay=%ld sec=%" PRIi64 " usec=%ld",
nbytes,
(long)tv.tv_usec,
(int64_t)s->wakeup.tv_sec,
(long)s->wakeup.tv_usec);
#endif
}
}
#if 0
/*
* Increase/Decrease bandwidth by a percentage.
*
* Return true if bandwidth changed.
*/
static inline bool
shaper_change_pct(struct shaper *s, int pct)
{
const int orig_bandwidth = s->bytes_per_second;
const int new_bandwidth = orig_bandwidth + (orig_bandwidth * pct / 100);
ASSERT(s->bytes_per_second);
shaper_reset(s, new_bandwidth);
return s->bytes_per_second != orig_bandwidth;
}
#endif
#endif /* ENABLE_FEATURE_SHAPER */
#endif /* ifndef SHAPER_H */
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