59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
/*
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* tc_cbq.c CBQ maintanance 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 <syslog.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 "tc_core.h"
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#include "tc_cbq.h"
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unsigned int tc_cbq_calc_maxidle(unsigned int bndw, unsigned int rate, unsigned int avpkt,
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int ewma_log, unsigned int maxburst)
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{
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double maxidle;
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double g = 1.0 - 1.0/(1<<ewma_log);
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double xmt = (double)avpkt/bndw;
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maxidle = xmt*(1-g);
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if (bndw != rate && maxburst) {
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double vxmt = (double)avpkt/rate - xmt;
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vxmt *= (pow(g, -(double)maxburst) - 1);
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if (vxmt > maxidle)
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maxidle = vxmt;
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}
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return tc_core_time2tick(maxidle*(1<<ewma_log)*TIME_UNITS_PER_SEC);
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}
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unsigned int tc_cbq_calc_offtime(unsigned int bndw, unsigned int rate, unsigned int avpkt,
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int ewma_log, unsigned int minburst)
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{
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double g = 1.0 - 1.0/(1<<ewma_log);
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double offtime = (double)avpkt/rate - (double)avpkt/bndw;
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if (minburst == 0)
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return 0;
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if (minburst == 1)
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offtime *= pow(g, -(double)minburst) - 1;
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else
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offtime *= 1 + (pow(g, -(double)(minburst-1)) - 1)/(1-g);
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return tc_core_time2tick(offtime*TIME_UNITS_PER_SEC);
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}
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