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/*
* Copyright 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.wifi;
import android.annotation.NonNull;
import android.net.wifi.WifiInfo;
/**
* Extends WifiInfo with the methods for computing the averaged packet rates
*/
public class ExtendedWifiInfo extends WifiInfo {
private static final long RESET_TIME_STAMP = Long.MIN_VALUE;
private static final double FILTER_TIME_CONSTANT = 3000.0;
private static final int SOURCE_UNKNOWN = 0;
private static final int SOURCE_TRAFFIC_COUNTERS = 1;
private static final int SOURCE_LLSTATS = 2;
private int mLastSource = SOURCE_UNKNOWN;
private long mLastPacketCountUpdateTimeStamp = RESET_TIME_STAMP;
private boolean mEnableConnectedMacRandomization = false;
@Override
public void reset() {
super.reset();
mLastSource = SOURCE_UNKNOWN;
mLastPacketCountUpdateTimeStamp = RESET_TIME_STAMP;
if (mEnableConnectedMacRandomization) {
setMacAddress(DEFAULT_MAC_ADDRESS);
}
}
/**
* Updates the packet rates using link layer stats
*
* @param stats WifiLinkLayerStats
* @param timeStamp time in milliseconds
*/
public void updatePacketRates(@NonNull WifiLinkLayerStats stats, long timeStamp) {
long txgood = stats.txmpdu_be + stats.txmpdu_bk + stats.txmpdu_vi + stats.txmpdu_vo;
long txretries = stats.retries_be + stats.retries_bk + stats.retries_vi + stats.retries_vo;
long txbad = stats.lostmpdu_be + stats.lostmpdu_bk + stats.lostmpdu_vi + stats.lostmpdu_vo;
long rxgood = stats.rxmpdu_be + stats.rxmpdu_bk + stats.rxmpdu_vi + stats.rxmpdu_vo;
update(SOURCE_LLSTATS, txgood, txretries, txbad, rxgood, timeStamp);
}
/**
* This function is less powerful and used if the WifiLinkLayerStats API is not implemented
* at the Wifi HAL
*/
public void updatePacketRates(long txPackets, long rxPackets, long timeStamp) {
update(SOURCE_TRAFFIC_COUNTERS, txPackets, 0, 0, rxPackets, timeStamp);
}
private void update(int source, long txgood, long txretries, long txbad, long rxgood,
long timeStamp) {
if (source == mLastSource
&& mLastPacketCountUpdateTimeStamp != RESET_TIME_STAMP
&& mLastPacketCountUpdateTimeStamp < timeStamp
&& txBad <= txbad
&& txSuccess <= txgood
&& rxSuccess <= rxgood
&& txRetries <= txretries) {
long timeDelta = timeStamp - mLastPacketCountUpdateTimeStamp;
double lastSampleWeight = Math.exp(-1.0 * timeDelta / FILTER_TIME_CONSTANT);
double currentSampleWeight = 1.0 - lastSampleWeight;
txBadRate = txBadRate * lastSampleWeight
+ (txbad - txBad) * 1000.0 / timeDelta
* currentSampleWeight;
txSuccessRate = txSuccessRate * lastSampleWeight
+ (txgood - txSuccess) * 1000.0 / timeDelta
* currentSampleWeight;
rxSuccessRate = rxSuccessRate * lastSampleWeight
+ (rxgood - rxSuccess) * 1000.0 / timeDelta
* currentSampleWeight;
txRetriesRate = txRetriesRate * lastSampleWeight
+ (txretries - txRetries) * 1000.0 / timeDelta
* currentSampleWeight;
} else {
txBadRate = 0;
txSuccessRate = 0;
rxSuccessRate = 0;
txRetriesRate = 0;
mLastSource = source;
}
txBad = txbad;
txSuccess = txgood;
rxSuccess = rxgood;
txRetries = txretries;
mLastPacketCountUpdateTimeStamp = timeStamp;
}
/**
* Updates whether Connected MAC Randomization is enabled.
*
* @hide
*/
public void setEnableConnectedMacRandomization(boolean enableConnectedMacRandomization) {
mEnableConnectedMacRandomization = enableConnectedMacRandomization;
}
}
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