/*
|
* Copyright 2019 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 com.android.server.wifi.WifiCandidates.Candidate;
|
import com.android.server.wifi.WifiCandidates.ScoredCandidate;
|
|
import java.util.Collection;
|
|
/**
|
* A candidate scorer that attempts to match the previous behavior.
|
*/
|
final class CompatibilityScorer implements WifiCandidates.CandidateScorer {
|
|
/**
|
* This should match WifiNetworkSelector.experimentIdFromIdentifier(getIdentifier())
|
* when using the default ScoringParams.
|
*/
|
public static final int COMPATIBILITY_SCORER_DEFAULT_EXPID = 42504592;
|
|
private final ScoringParams mScoringParams;
|
|
// config_wifi_framework_RSSI_SCORE_OFFSET
|
public static final int RSSI_SCORE_OFFSET = 85;
|
|
// config_wifi_framework_RSSI_SCORE_SLOPE
|
public static final int RSSI_SCORE_SLOPE_IS_4 = 4;
|
|
// config_wifi_framework_5GHz_preference_boost_factor
|
public static final int BAND_5GHZ_AWARD_IS_40 = 40;
|
|
// config_wifi_framework_SECURITY_AWARD
|
public static final int SECURITY_AWARD_IS_80 = 80;
|
|
// config_wifi_framework_LAST_SELECTION_AWARD
|
public static final int LAST_SELECTION_AWARD_IS_480 = 480;
|
|
// config_wifi_framework_current_network_boost
|
public static final int CURRENT_NETWORK_BOOST_IS_16 = 16;
|
|
// config_wifi_framework_SAME_BSSID_AWARD
|
public static final int SAME_BSSID_AWARD_IS_24 = 24;
|
|
CompatibilityScorer(ScoringParams scoringParams) {
|
mScoringParams = scoringParams;
|
}
|
|
@Override
|
public String getIdentifier() {
|
return "CompatibilityScorer";
|
}
|
|
/**
|
* Calculates an individual candidate's score.
|
*/
|
private ScoredCandidate scoreCandidate(Candidate candidate) {
|
int rssiSaturationThreshold = mScoringParams.getGoodRssi(candidate.getFrequency());
|
int rssi = Math.min(candidate.getScanRssi(), rssiSaturationThreshold);
|
int score = (rssi + RSSI_SCORE_OFFSET) * RSSI_SCORE_SLOPE_IS_4;
|
|
if (candidate.getFrequency() >= ScoringParams.MINIMUM_5GHZ_BAND_FREQUENCY_IN_MEGAHERTZ) {
|
score += BAND_5GHZ_AWARD_IS_40;
|
}
|
score += (int) (candidate.getLastSelectionWeight() * LAST_SELECTION_AWARD_IS_480);
|
|
if (candidate.isCurrentNetwork()) {
|
// Add both traditional awards, as would be be case with firmware roaming
|
score += CURRENT_NETWORK_BOOST_IS_16 + SAME_BSSID_AWARD_IS_24;
|
}
|
|
if (!candidate.isOpenNetwork()) {
|
score += SECURITY_AWARD_IS_80;
|
}
|
|
// To simulate the old strict priority rule, subtract a penalty based on
|
// which evaluator added the candidate.
|
score -= 1000 * candidate.getEvaluatorId();
|
|
// The old method breaks ties on the basis of RSSI, which we can
|
// emulate easily since our score does not need to be an integer.
|
double tieBreaker = candidate.getScanRssi() / 1000.0;
|
return new ScoredCandidate(score + tieBreaker, 10, candidate);
|
}
|
|
@Override
|
public ScoredCandidate scoreCandidates(@NonNull Collection<Candidate> group) {
|
ScoredCandidate choice = ScoredCandidate.NONE;
|
for (Candidate candidate : group) {
|
ScoredCandidate scoredCandidate = scoreCandidate(candidate);
|
if (scoredCandidate.value > choice.value) {
|
choice = scoredCandidate;
|
}
|
}
|
// Here we just return the highest scored candidate; we could
|
// compute a new score, if desired.
|
return choice;
|
}
|
|
@Override
|
public boolean userConnectChoiceOverrideWanted() {
|
return true;
|
}
|
|
}
|
