mirror of
https://git.kernel.org/pub/scm/network/iproute2/iproute2.git
synced 2024-11-16 14:35:34 +08:00
98 lines
1.8 KiB
C
98 lines
1.8 KiB
C
/*
|
|
* tc_red.c RED maintanance routines.
|
|
*
|
|
* 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.
|
|
*
|
|
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
|
|
*
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <syslog.h>
|
|
#include <fcntl.h>
|
|
#include <math.h>
|
|
#include <sys/socket.h>
|
|
#include <netinet/in.h>
|
|
#include <arpa/inet.h>
|
|
#include <string.h>
|
|
|
|
#include "tc_core.h"
|
|
#include "tc_red.h"
|
|
|
|
/*
|
|
Plog = log(prob/(qmax - qmin))
|
|
*/
|
|
int tc_red_eval_P(unsigned qmin, unsigned qmax, double prob)
|
|
{
|
|
int i = qmax - qmin;
|
|
|
|
if (i <= 0)
|
|
return -1;
|
|
|
|
prob /= i;
|
|
|
|
for (i=0; i<32; i++) {
|
|
if (prob > 1.0)
|
|
break;
|
|
prob *= 2;
|
|
}
|
|
if (i>=32)
|
|
return -1;
|
|
return i;
|
|
}
|
|
|
|
/*
|
|
burst + 1 - qmin/avpkt < (1-(1-W)^burst)/W
|
|
*/
|
|
|
|
int tc_red_eval_ewma(unsigned qmin, unsigned burst, unsigned avpkt)
|
|
{
|
|
int wlog = 1;
|
|
double W = 0.5;
|
|
double a = (double)burst + 1 - (double)qmin/avpkt;
|
|
|
|
if (a < 1.0)
|
|
return -1;
|
|
for (wlog=1; wlog<32; wlog++, W /= 2) {
|
|
if (a <= (1 - pow(1-W, burst))/W)
|
|
return wlog;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
Stab[t>>Scell_log] = -log(1-W) * t/xmit_time
|
|
*/
|
|
|
|
int tc_red_eval_idle_damping(int Wlog, unsigned avpkt, unsigned bps, __u8 *sbuf)
|
|
{
|
|
double xmit_time = tc_core_usec2tick(1000000*(double)avpkt/bps);
|
|
double lW = -log(1.0 - 1.0/(1<<Wlog))/xmit_time;
|
|
double maxtime = 31/lW;
|
|
int clog;
|
|
int i;
|
|
double tmp;
|
|
|
|
tmp = maxtime;
|
|
for (clog=0; clog<32; clog++) {
|
|
if (maxtime/(1<<clog) < 512)
|
|
break;
|
|
}
|
|
if (clog >= 32)
|
|
return -1;
|
|
|
|
sbuf[0] = 0;
|
|
for (i=1; i<255; i++) {
|
|
sbuf[i] = (i<<clog)*lW;
|
|
if (sbuf[i] > 31)
|
|
sbuf[i] = 31;
|
|
}
|
|
sbuf[255] = 31;
|
|
return clog;
|
|
}
|