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/*
* Copyright (C) 2016 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.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiConfiguration;
import android.util.LocalLog;
import android.util.Pair;
import com.android.internal.R;
import com.android.server.wifi.util.TelephonyUtil;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* This class is the WifiNetworkSelector.NetworkEvaluator implementation for
* saved networks.
*/
public class SavedNetworkEvaluator implements WifiNetworkSelector.NetworkEvaluator {
private static final String NAME = "SavedNetworkEvaluator";
private final WifiConfigManager mWifiConfigManager;
private final Clock mClock;
private final LocalLog mLocalLog;
private final WifiConnectivityHelper mConnectivityHelper;
private final int mRssiScoreSlope;
private final int mRssiScoreOffset;
private final int mSameBssidAward;
private final int mSameNetworkAward;
private final int mBand5GHzAward;
private final int mLastSelectionAward;
private final int mSecurityAward;
private final int mThresholdSaturatedRssi24;
private final int mThresholdSaturatedRssi5;
SavedNetworkEvaluator(final Context context, WifiConfigManager configManager, Clock clock,
LocalLog localLog, WifiConnectivityHelper connectivityHelper) {
mWifiConfigManager = configManager;
mClock = clock;
mLocalLog = localLog;
mConnectivityHelper = connectivityHelper;
mRssiScoreSlope = context.getResources().getInteger(
R.integer.config_wifi_framework_RSSI_SCORE_SLOPE);
mRssiScoreOffset = context.getResources().getInteger(
R.integer.config_wifi_framework_RSSI_SCORE_OFFSET);
mSameBssidAward = context.getResources().getInteger(
R.integer.config_wifi_framework_SAME_BSSID_AWARD);
mSameNetworkAward = context.getResources().getInteger(
R.integer.config_wifi_framework_current_network_boost);
mLastSelectionAward = context.getResources().getInteger(
R.integer.config_wifi_framework_LAST_SELECTION_AWARD);
mSecurityAward = context.getResources().getInteger(
R.integer.config_wifi_framework_SECURITY_AWARD);
mBand5GHzAward = context.getResources().getInteger(
R.integer.config_wifi_framework_5GHz_preference_boost_factor);
mThresholdSaturatedRssi24 = context.getResources().getInteger(
R.integer.config_wifi_framework_wifi_score_good_rssi_threshold_24GHz);
mThresholdSaturatedRssi5 = context.getResources().getInteger(
R.integer.config_wifi_framework_wifi_score_good_rssi_threshold_5GHz);
}
private void localLog(String log) {
mLocalLog.log(log);
}
/**
* Get the evaluator name.
*/
public String getName() {
return NAME;
}
/**
* Update all the saved networks' selection status
*/
private void updateSavedNetworkSelectionStatus() {
List<WifiConfiguration> savedNetworks = mWifiConfigManager.getSavedNetworks();
if (savedNetworks.size() == 0) {
localLog("No saved networks.");
return;
}
StringBuffer sbuf = new StringBuffer();
for (WifiConfiguration network : savedNetworks) {
/**
* Ignore Passpoint networks. Passpoint networks are also considered as "saved"
* network, but without being persisted to the storage. They are managed
* by {@link PasspointNetworkEvaluator}.
*/
if (network.isPasspoint()) {
continue;
}
// If a configuration is temporarily disabled, re-enable it before trying
// to connect to it.
mWifiConfigManager.tryEnableNetwork(network.networkId);
//TODO(b/30928589): Enable "permanently" disabled networks if we are in DISCONNECTED
// state.
// Clear the cached candidate, score and seen.
mWifiConfigManager.clearNetworkCandidateScanResult(network.networkId);
// Log disabled network.
WifiConfiguration.NetworkSelectionStatus status = network.getNetworkSelectionStatus();
if (!status.isNetworkEnabled()) {
sbuf.append(" ").append(WifiNetworkSelector.toNetworkString(network)).append(" ");
for (int index = WifiConfiguration.NetworkSelectionStatus
.NETWORK_SELECTION_DISABLED_STARTING_INDEX;
index < WifiConfiguration.NetworkSelectionStatus
.NETWORK_SELECTION_DISABLED_MAX;
index++) {
int count = status.getDisableReasonCounter(index);
// Here we log the reason as long as its count is greater than zero. The
// network may not be disabled because of this particular reason. Logging
// this information anyway to help understand what happened to the network.
if (count > 0) {
sbuf.append("reason=")
.append(WifiConfiguration.NetworkSelectionStatus
.getNetworkDisableReasonString(index))
.append(", count=").append(count).append("; ");
}
}
sbuf.append("\n");
}
}
if (sbuf.length() > 0) {
localLog("Disabled saved networks:");
localLog(sbuf.toString());
}
}
/**
* Update the evaluator.
*/
public void update(List<ScanDetail> scanDetails) {
updateSavedNetworkSelectionStatus();
}
private int calculateBssidScore(ScanResult scanResult, WifiConfiguration network,
WifiConfiguration currentNetwork, String currentBssid,
StringBuffer sbuf) {
int score = 0;
boolean is5GHz = scanResult.is5GHz();
sbuf.append("[ ").append(scanResult.SSID).append(" ").append(scanResult.BSSID)
.append(" RSSI:").append(scanResult.level).append(" ] ");
// Calculate the RSSI score.
int rssiSaturationThreshold = is5GHz ? mThresholdSaturatedRssi5 : mThresholdSaturatedRssi24;
int rssi = scanResult.level < rssiSaturationThreshold ? scanResult.level
: rssiSaturationThreshold;
score += (rssi + mRssiScoreOffset) * mRssiScoreSlope;
sbuf.append(" RSSI score: ").append(score).append(",");
// 5GHz band bonus.
if (is5GHz) {
score += mBand5GHzAward;
sbuf.append(" 5GHz bonus: ").append(mBand5GHzAward).append(",");
}
// Last user selection award.
int lastUserSelectedNetworkId = mWifiConfigManager.getLastSelectedNetwork();
if (lastUserSelectedNetworkId != WifiConfiguration.INVALID_NETWORK_ID
&& lastUserSelectedNetworkId == network.networkId) {
long timeDifference = mClock.getElapsedSinceBootMillis()
- mWifiConfigManager.getLastSelectedTimeStamp();
if (timeDifference > 0) {
int bonus = mLastSelectionAward - (int) (timeDifference / 1000 / 60);
score += bonus > 0 ? bonus : 0;
sbuf.append(" User selection ").append(timeDifference / 1000 / 60)
.append(" minutes ago, bonus: ").append(bonus).append(",");
}
}
// Same network award.
if (currentNetwork != null
&& (network.networkId == currentNetwork.networkId
//TODO(b/36788683): re-enable linked configuration check
/* || network.isLinked(currentNetwork) */)) {
score += mSameNetworkAward;
sbuf.append(" Same network bonus: ").append(mSameNetworkAward).append(",");
// When firmware roaming is supported, equivalent BSSIDs (the ones under the
// same network as the currently connected one) get the same BSSID award.
if (mConnectivityHelper.isFirmwareRoamingSupported()
&& currentBssid != null && !currentBssid.equals(scanResult.BSSID)) {
score += mSameBssidAward;
sbuf.append(" Equivalent BSSID bonus: ").append(mSameBssidAward).append(",");
}
}
// Same BSSID award.
if (currentBssid != null && currentBssid.equals(scanResult.BSSID)) {
score += mSameBssidAward;
sbuf.append(" Same BSSID bonus: ").append(mSameBssidAward).append(",");
}
// Security award.
if (!WifiConfigurationUtil.isConfigForOpenNetwork(network)) {
score += mSecurityAward;
sbuf.append(" Secure network bonus: ").append(mSecurityAward).append(",");
}
sbuf.append(" ## Total score: ").append(score).append("\n");
return score;
}
/**
* Evaluate all the networks from the scan results and return
* the WifiConfiguration of the network chosen for connection.
*
* @return configuration of the chosen network;
* null if no network in this category is available.
*/
public WifiConfiguration evaluateNetworks(List<ScanDetail> scanDetails,
WifiConfiguration currentNetwork, String currentBssid, boolean connected,
boolean untrustedNetworkAllowed,
List<Pair<ScanDetail, WifiConfiguration>> connectableNetworks) {
int highestScore = Integer.MIN_VALUE;
ScanResult scanResultCandidate = null;
WifiConfiguration candidate = null;
StringBuffer scoreHistory = new StringBuffer();
for (ScanDetail scanDetail : scanDetails) {
ScanResult scanResult = scanDetail.getScanResult();
int highestScoreOfScanResult = Integer.MIN_VALUE;
int candidateIdOfScanResult = WifiConfiguration.INVALID_NETWORK_ID;
// One ScanResult can be associated with more than one networks, hence we calculate all
// the scores and use the highest one as the ScanResult's score.
List<WifiConfiguration> associatedConfigurations = null;
WifiConfiguration associatedConfiguration =
mWifiConfigManager.getConfiguredNetworkForScanDetailAndCache(scanDetail);
if (associatedConfiguration == null) {
continue;
} else {
associatedConfigurations =
new ArrayList<>(Arrays.asList(associatedConfiguration));
}
for (WifiConfiguration network : associatedConfigurations) {
/**
* Ignore Passpoint and Ephemeral networks. They are configured networks,
* but without being persisted to the storage. They are evaluated by
* {@link PasspointNetworkEvaluator} and {@link ScoredNetworkEvaluator}
* respectively.
*/
if (network.isPasspoint() || network.isEphemeral()) {
continue;
}
WifiConfiguration.NetworkSelectionStatus status =
network.getNetworkSelectionStatus();
status.setSeenInLastQualifiedNetworkSelection(true);
if (!status.isNetworkEnabled()) {
continue;
} else if (network.BSSID != null && !network.BSSID.equals("any")
&& !network.BSSID.equals(scanResult.BSSID)) {
// App has specified the only BSSID to connect for this
// configuration. So only the matching ScanResult can be a candidate.
localLog("Network " + WifiNetworkSelector.toNetworkString(network)
+ " has specified BSSID " + network.BSSID + ". Skip "
+ scanResult.BSSID);
continue;
} else if (TelephonyUtil.isSimConfig(network)
&& !mWifiConfigManager.isSimPresent()) {
// Don't select if security type is EAP SIM/AKA/AKA' when SIM is not present.
continue;
}
int score = calculateBssidScore(scanResult, network, currentNetwork, currentBssid,
scoreHistory);
// Set candidate ScanResult for all saved networks to ensure that users can
// override network selection. See WifiNetworkSelector#setUserConnectChoice.
// TODO(b/36067705): consider alternative designs to push filtering/selecting of
// user connect choice networks to RecommendedNetworkEvaluator.
if (score > status.getCandidateScore() || (score == status.getCandidateScore()
&& status.getCandidate() != null
&& scanResult.level > status.getCandidate().level)) {
mWifiConfigManager.setNetworkCandidateScanResult(
network.networkId, scanResult, score);
}
// If the network is marked to use external scores, or is an open network with
// curate saved open networks enabled, do not consider it for network selection.
if (network.useExternalScores) {
localLog("Network " + WifiNetworkSelector.toNetworkString(network)
+ " has external score.");
continue;
}
if (score > highestScoreOfScanResult) {
highestScoreOfScanResult = score;
candidateIdOfScanResult = network.networkId;
}
}
if (connectableNetworks != null) {
connectableNetworks.add(Pair.create(scanDetail,
mWifiConfigManager.getConfiguredNetwork(candidateIdOfScanResult)));
}
if (highestScoreOfScanResult > highestScore
|| (highestScoreOfScanResult == highestScore
&& scanResultCandidate != null
&& scanResult.level > scanResultCandidate.level)) {
highestScore = highestScoreOfScanResult;
scanResultCandidate = scanResult;
mWifiConfigManager.setNetworkCandidateScanResult(
candidateIdOfScanResult, scanResultCandidate, highestScore);
// Reload the network config with the updated info.
candidate = mWifiConfigManager.getConfiguredNetwork(candidateIdOfScanResult);
}
}
if (scoreHistory.length() > 0) {
localLog("\n" + scoreHistory.toString());
}
if (scanResultCandidate == null) {
localLog("did not see any good candidates.");
}
return candidate;
}
}