Blame tc/tc_red.c

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/*
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 * tc_red.c		RED maintenance routines.
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 *
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 *		This program is free software; you can redistribute it and/or
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 *		modify it under the terms of the GNU General Public License
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 *		as published by the Free Software Foundation; either version
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 *		2 of the License, or (at your option) any later version.
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 *
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 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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 *
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <math.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include "utils.h"
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#include "tc_core.h"
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#include "tc_util.h"
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#include "tc_red.h"
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/*
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   Plog = log(prob/(qmax - qmin))
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 */
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int tc_red_eval_P(unsigned int qmin, unsigned int qmax, double prob)
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{
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	int i = qmax - qmin;
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	if (!i)
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		return 0;
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	if (i < 0)
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		return -1;
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	prob /= i;
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	for (i = 0; i < 32; i++) {
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		if (prob > 1.0)
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			break;
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		prob *= 2;
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	}
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	if (i >= 32)
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		return -1;
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	return i;
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}
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/*
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   burst + 1 - qmin/avpkt < (1-(1-W)^burst)/W
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 */
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int tc_red_eval_ewma(unsigned int qmin, unsigned int burst, unsigned int avpkt)
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{
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	int wlog = 1;
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	double W = 0.5;
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	double a = (double)burst + 1 - (double)qmin/avpkt;
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	if (a < 1.0) {
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		fprintf(stderr, "tc_red_eval_ewma() burst %u is too small ? Try burst %u\n",
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				burst, 1 + qmin/avpkt);
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		return -1;
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	}
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	for (wlog = 1; wlog < 32; wlog++, W /= 2) {
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		if (a <= (1 - pow(1-W, burst))/W)
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			return wlog;
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	}
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	return -1;
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}
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/*
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   Stab[t>>Scell_log] = -log(1-W) * t/xmit_time
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 */
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int tc_red_eval_idle_damping(int Wlog, unsigned int avpkt, unsigned int bps, __u8 *sbuf)
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{
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	double xmit_time = tc_calc_xmittime(bps, avpkt);
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	double lW = -log(1.0 - 1.0/(1<
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	double maxtime = 31/lW;
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	int clog;
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	int i;
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	for (clog = 0; clog < 32; clog++) {
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		if (maxtime/(1<
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			break;
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	}
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	if (clog >= 32)
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		return -1;
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	sbuf[0] = 0;
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	for (i = 1; i < 255; i++) {
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		sbuf[i] = (i<
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		if (sbuf[i] > 31)
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			sbuf[i] = 31;
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	}
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	sbuf[255] = 31;
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	return clog;
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}
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void tc_red_print_flags(__u32 flags)
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{
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	if (flags & TC_RED_ECN)
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		print_bool(PRINT_ANY, "ecn", "ecn ", true);
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	else
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		print_bool(PRINT_ANY, "ecn", NULL, false);
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	if (flags & TC_RED_HARDDROP)
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		print_bool(PRINT_ANY, "harddrop", "harddrop ", true);
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	else
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		print_bool(PRINT_ANY, "harddrop", NULL, false);
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	if (flags & TC_RED_ADAPTATIVE)
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		print_bool(PRINT_ANY, "adaptive", "adaptive ", true);
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	else
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		print_bool(PRINT_ANY, "adaptive", NULL, false);
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	if (flags & TC_RED_NODROP)
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		print_bool(PRINT_ANY, "nodrop", "nodrop ", true);
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	else
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		print_bool(PRINT_ANY, "nodrop", NULL, false);
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}