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/*
VTun - Virtual Tunnel over TCP/IP network.
Copyright (C) 1998-2016 Maxim Krasnyansky <max_mk@yahoo.com>
VTun has been derived from VPPP package by Maxim Krasnyansky.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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.
*/
/*
* $Id: lfd_shaper.c,v 1.7.2.4 2016/10/01 21:27:51 mtbishop Exp $
*/
#include "config.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/time.h>
#include <syslog.h>
#include "vtun.h"
#include "linkfd.h"
#include "lib.h"
#include <time.h>
/*
* Shaper module.
*/
#ifdef HAVE_SHAPER
static unsigned long bytes, max_speed;
static struct timeval curr_time, last_time;
/*
* Initialization function.
*/
static int shaper_init(struct vtun_host *host)
{
/* Calculate max speed bytes/sec */
max_speed = host->spd_out / 8 * 1024;
/* Compensation for delays, nanosleep and so on */
max_speed += 400;
bytes = 0;
vtun_syslog(LOG_INFO,"Traffic shaping(speed %dK) initialized.", host->spd_out);
return 0;
}
/* Shaper counter */
static int shaper_counter(int len, char *in, char **out)
{
/* Just count incoming bytes */
bytes += len;
*out = in;
return len;
}
/* Convert tv struct to milisec */
static unsigned long inline tv2ms(struct timeval tv)
{
register unsigned long ms = (tv.tv_sec * 1000)+(tv.tv_usec / 1000);
return ms ? ms : 1;
}
#ifndef timersub
/* Some includes doesn't contain this macro */
#define timersub(a, b, result) \
do { \
(result)->tv_sec = (a)->tv_sec - (b)->tv_sec; \
(result)->tv_usec = (a)->tv_usec - (b)->tv_usec; \
if ((result)->tv_usec < 0) { \
--(result)->tv_sec; \
(result)->tv_usec += 1000000; \
} \
} while (0)
#endif
/*
* Main shaper function.
* Compute current speed in bytes/sec and if it is
* higher than maximal speed stop accepting input
* until the speed become lower or equal to maximal.
*/
static int shaper_avail(void)
{
static struct timeval tv;
register unsigned long speed;
/* Let me know if you have faster and better time source. */
gettimeofday(&curr_time,NULL);
timersub(&curr_time,&last_time,&tv);
/* Calculate current speed bytes/sec.
* (tv2ms never returns 0) */
speed = bytes * 1000 / tv2ms(tv);
if( speed > max_speed ){
/*
* Sleep about 1 microsec(actual sleep might be longer).
* This is actually the hack to reduce CPU usage.
* Without this delay we will consume 100% CPU.
*/
static struct timespec ts = {0,1000};
nanosleep(&ts,NULL);
/* Don't accept input */
return 0;
}
if( curr_time.tv_sec > last_time.tv_sec ){
last_time = curr_time;
bytes = 0;
}
/* Accept input */
return 1;
}
struct lfd_mod lfd_shaper = {
"Shaper",
shaper_init,
shaper_counter,
shaper_avail,
NULL,
NULL,
NULL,
NULL,
NULL
};
#else /* HAVE_SHAPER */
static int no_shaper(struct vtun_host *host)
{
vtun_syslog(LOG_INFO, "Traffic shaping is not supported");
return -1;
}
struct lfd_mod lfd_shaper = {
"Shaper",
no_shaper, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};
#endif /* HAVE_SHAPER */
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