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63 lines
2 KiB
C++
63 lines
2 KiB
C++
/*
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*
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* (C) 2013-25 - ntop.org
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#ifndef _HW_COUNTER_H_
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#define _HW_COUNTER_H_
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#include "ntop_includes.h"
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/* Counter based on Holt-Winters algorithm */
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class HWCounter : public BehaviouralCounter {
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private:
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struct ndpi_hw_struct hw;
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public:
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HWCounter(u_int16_t num_learning_observations =
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1 /* Basically smoothing without seasonality */,
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double alpha = 0.7, double beta = 0.7, double gamma = 0.9)
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: BehaviouralCounter() {
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if (ndpi_hw_init(&hw, num_learning_observations, 1 /* additive */, alpha,
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beta, gamma, 0.05 /* 95% */) != 0)
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throw "Error while creating HW";
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}
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~HWCounter() { ndpi_hw_free(&hw); }
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bool addObservation(u_int64_t value) {
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double forecast, confidence_band;
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bool rc = ndpi_hw_add_value(&hw, last_value = value, &forecast,
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&confidence_band) == 1
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? true
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: false;
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double l_forecast = forecast - confidence_band;
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double h_forecast = forecast + confidence_band;
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last_lower = (u_int64_t)floor(((l_forecast < 0) ? 0 : l_forecast)),
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last_upper = (u_int64_t)round(h_forecast + 0.5), is_anomaly = rc;
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if (is_anomaly) tot_num_anomalies++;
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return (is_anomaly);
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}
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inline void resetStats() { ndpi_hw_reset(&hw); }
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};
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#endif /* _HW_COUNTER_H_ */
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