Alan Viverette | 3da604b | 2020-06-10 18:34:39 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.server.wifi; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.annotation.Nullable; |
| 21 | import android.content.Context; |
| 22 | import android.content.pm.PackageManager; |
| 23 | import android.database.ContentObserver; |
| 24 | import android.net.NetworkKey; |
| 25 | import android.net.NetworkScoreManager; |
| 26 | import android.net.wifi.ScanResult; |
| 27 | import android.net.wifi.WifiConfiguration; |
| 28 | import android.os.Handler; |
| 29 | import android.provider.Settings; |
| 30 | import android.text.TextUtils; |
| 31 | import android.util.LocalLog; |
| 32 | import android.util.Log; |
| 33 | import android.util.Pair; |
| 34 | |
| 35 | import com.android.internal.annotations.VisibleForTesting; |
| 36 | import com.android.server.wifi.util.ScanResultUtil; |
| 37 | import com.android.server.wifi.util.WifiPermissionsUtil; |
| 38 | |
| 39 | import java.util.ArrayList; |
| 40 | import java.util.List; |
| 41 | |
| 42 | /** |
| 43 | * {@link WifiNetworkSelector.NetworkNominator} implementation that uses scores obtained by |
| 44 | * {@link NetworkScoreManager#requestScores(NetworkKey[])} to make network connection decisions. |
| 45 | */ |
| 46 | public class ScoredNetworkNominator implements WifiNetworkSelector.NetworkNominator { |
| 47 | private static final String TAG = "ScoredNetworkNominator"; |
| 48 | // TODO (b/150977740): Stop using the @hide settings global flag. |
| 49 | @VisibleForTesting |
| 50 | public static final String SETTINGS_GLOBAL_USE_OPEN_WIFI_PACKAGE = |
| 51 | "use_open_wifi_package"; |
| 52 | private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG); |
| 53 | |
| 54 | private final NetworkScoreManager mNetworkScoreManager; |
| 55 | private final PackageManager mPackageManager; |
| 56 | private final WifiConfigManager mWifiConfigManager; |
| 57 | private final LocalLog mLocalLog; |
| 58 | private final ContentObserver mContentObserver; |
| 59 | private final WifiPermissionsUtil mWifiPermissionsUtil; |
| 60 | private boolean mNetworkRecommendationsEnabled; |
| 61 | private WifiNetworkScoreCache mScoreCache; |
| 62 | |
| 63 | ScoredNetworkNominator(final Context context, Handler handler, |
| 64 | final FrameworkFacade frameworkFacade, NetworkScoreManager networkScoreManager, |
| 65 | PackageManager packageManager, |
| 66 | WifiConfigManager wifiConfigManager, LocalLog localLog, |
| 67 | WifiNetworkScoreCache wifiNetworkScoreCache, |
| 68 | WifiPermissionsUtil wifiPermissionsUtil) { |
| 69 | mScoreCache = wifiNetworkScoreCache; |
| 70 | mWifiPermissionsUtil = wifiPermissionsUtil; |
| 71 | mNetworkScoreManager = networkScoreManager; |
| 72 | mPackageManager = packageManager; |
| 73 | mWifiConfigManager = wifiConfigManager; |
| 74 | mLocalLog = localLog; |
| 75 | mContentObserver = new ContentObserver(handler) { |
| 76 | @Override |
| 77 | public void onChange(boolean selfChange) { |
| 78 | mNetworkRecommendationsEnabled = frameworkFacade.getStringSetting(context, |
| 79 | SETTINGS_GLOBAL_USE_OPEN_WIFI_PACKAGE) != null; |
| 80 | } |
| 81 | }; |
| 82 | frameworkFacade.registerContentObserver(context, |
| 83 | Settings.Global.getUriFor(SETTINGS_GLOBAL_USE_OPEN_WIFI_PACKAGE), |
| 84 | false /* notifyForDescendents */, mContentObserver); |
| 85 | mContentObserver.onChange(false /* unused */); |
| 86 | mLocalLog.log("ScoredNetworkNominator constructed. mNetworkRecommendationsEnabled: " |
| 87 | + mNetworkRecommendationsEnabled); |
| 88 | } |
| 89 | |
| 90 | @Override |
| 91 | public void update(List<ScanDetail> scanDetails) { |
| 92 | if (mNetworkRecommendationsEnabled) { |
| 93 | updateNetworkScoreCache(scanDetails); |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | private void updateNetworkScoreCache(List<ScanDetail> scanDetails) { |
| 98 | ArrayList<NetworkKey> unscoredNetworks = new ArrayList<NetworkKey>(); |
| 99 | for (int i = 0; i < scanDetails.size(); i++) { |
| 100 | ScanResult scanResult = scanDetails.get(i).getScanResult(); |
| 101 | NetworkKey networkKey = NetworkKey.createFromScanResult(scanResult); |
| 102 | if (networkKey != null) { |
| 103 | // Is there a ScoredNetwork for this ScanResult? If not, request a score. |
| 104 | if (mScoreCache.getScoredNetwork(networkKey) == null) { |
| 105 | unscoredNetworks.add(networkKey); |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | // Kick the score manager if there are any unscored network. |
| 111 | if (!unscoredNetworks.isEmpty() && activeScorerAllowedtoSeeScanResults()) { |
| 112 | mNetworkScoreManager.requestScores(unscoredNetworks); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | private Pair<Integer, String> getActiveScorerUidAndPackage() { |
| 117 | String packageName = mNetworkScoreManager.getActiveScorerPackage(); |
| 118 | if (packageName == null) return null; |
| 119 | int uid = -1; |
| 120 | try { |
| 121 | uid = mPackageManager.getApplicationInfo(packageName, 0).uid; |
| 122 | } catch (PackageManager.NameNotFoundException e) { |
| 123 | Log.e(TAG, "Failed to retrieve package uid", e); |
| 124 | return null; |
| 125 | } |
| 126 | return Pair.create(uid, packageName); |
| 127 | } |
| 128 | |
| 129 | private boolean activeScorerAllowedtoSeeScanResults() { |
| 130 | Pair<Integer, String> scorerUidAndPackage = getActiveScorerUidAndPackage(); |
| 131 | if (scorerUidAndPackage == null) return false; |
| 132 | try { |
| 133 | // TODO moltmann: Can we set a featureID here instead of null? |
| 134 | mWifiPermissionsUtil.enforceCanAccessScanResults( |
| 135 | scorerUidAndPackage.second, null, scorerUidAndPackage.first, null); |
| 136 | return true; |
| 137 | } catch (SecurityException e) { |
| 138 | return false; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | @Override |
| 143 | public void nominateNetworks(List<ScanDetail> scanDetails, |
| 144 | WifiConfiguration currentNetwork, String currentBssid, boolean connected, |
| 145 | boolean untrustedNetworkAllowed, |
| 146 | @NonNull OnConnectableListener onConnectableListener) { |
| 147 | if (!mNetworkRecommendationsEnabled) { |
| 148 | mLocalLog.log("Skipping nominateNetworks; Network recommendations disabled."); |
| 149 | return; |
| 150 | } |
| 151 | |
| 152 | final ScoreTracker scoreTracker = new ScoreTracker(); |
| 153 | for (int i = 0; i < scanDetails.size(); i++) { |
| 154 | ScanDetail scanDetail = scanDetails.get(i); |
| 155 | ScanResult scanResult = scanDetail.getScanResult(); |
| 156 | if (scanResult == null) continue; |
| 157 | if (mWifiConfigManager.isNetworkTemporarilyDisabledByUser( |
| 158 | ScanResultUtil.createQuotedSSID(scanResult.SSID))) { |
| 159 | debugLog("Ignoring user disabled SSID: " + scanResult.SSID); |
| 160 | continue; |
| 161 | } |
| 162 | final WifiConfiguration configuredNetwork = |
| 163 | mWifiConfigManager.getConfiguredNetworkForScanDetailAndCache(scanDetail); |
| 164 | boolean untrustedScanResult = configuredNetwork == null || !configuredNetwork.trusted; |
| 165 | |
| 166 | if (!untrustedNetworkAllowed && untrustedScanResult) { |
| 167 | continue; |
| 168 | } |
| 169 | |
| 170 | // Track scan results for open wifi networks |
| 171 | if (configuredNetwork == null) { |
| 172 | if (ScanResultUtil.isScanResultForOpenNetwork(scanResult)) { |
| 173 | scoreTracker.trackUntrustedCandidate(scanDetail); |
| 174 | } |
| 175 | continue; |
| 176 | } |
| 177 | |
| 178 | // Ignore trusted and non-externally scored networks |
| 179 | if (configuredNetwork.trusted && !configuredNetwork.useExternalScores) { |
| 180 | continue; |
| 181 | } |
| 182 | |
| 183 | // Ignore externally scored or ephemeral networks that have been disabled for selection |
| 184 | if (!configuredNetwork.getNetworkSelectionStatus().isNetworkEnabled()) { |
| 185 | debugLog("Ignoring disabled SSID: " + configuredNetwork.SSID); |
| 186 | continue; |
| 187 | } |
| 188 | |
| 189 | // TODO(b/37485956): consider applying a boost for networks with only the same SSID |
| 190 | boolean isCurrentNetwork = currentNetwork != null |
| 191 | && currentNetwork.networkId == configuredNetwork.networkId |
| 192 | && TextUtils.equals(currentBssid, scanResult.BSSID); |
| 193 | if (!configuredNetwork.trusted) { |
| 194 | scoreTracker.trackUntrustedCandidate( |
| 195 | scanResult, configuredNetwork, isCurrentNetwork); |
| 196 | } else { |
| 197 | scoreTracker.trackExternallyScoredCandidate( |
| 198 | scanResult, configuredNetwork, isCurrentNetwork); |
| 199 | } |
| 200 | onConnectableListener.onConnectable(scanDetail, configuredNetwork); |
| 201 | } |
| 202 | scoreTracker.getCandidateConfiguration(onConnectableListener); |
| 203 | } |
| 204 | |
| 205 | /** Used to track the network with the highest score. */ |
| 206 | class ScoreTracker { |
| 207 | private static final int EXTERNAL_SCORED_NONE = 0; |
| 208 | private static final int EXTERNAL_SCORED_SAVED_NETWORK = 1; |
| 209 | private static final int EXTERNAL_SCORED_UNTRUSTED_NETWORK = 2; |
| 210 | |
| 211 | private int mBestCandidateType = EXTERNAL_SCORED_NONE; |
| 212 | private int mHighScore = WifiNetworkScoreCache.INVALID_NETWORK_SCORE; |
| 213 | private WifiConfiguration mEphemeralConfig; |
| 214 | private WifiConfiguration mSavedConfig; |
| 215 | private ScanResult mScanResultCandidate; |
| 216 | private ScanDetail mScanDetailCandidate; |
| 217 | |
| 218 | /** |
| 219 | * Returns the available external network score or null if no score is available. |
| 220 | * |
| 221 | * @param scanResult The scan result of the network to score. |
| 222 | * @param isCurrentNetwork Flag which indicates whether this is the current network. |
| 223 | * @return A valid external score if one is available or NULL. |
| 224 | */ |
| 225 | @Nullable |
| 226 | private Integer getNetworkScore(ScanResult scanResult, boolean isCurrentNetwork) { |
| 227 | if (mScoreCache.isScoredNetwork(scanResult)) { |
| 228 | int score = mScoreCache.getNetworkScore(scanResult, isCurrentNetwork); |
| 229 | if (DEBUG) { |
| 230 | mLocalLog.log(WifiNetworkSelector.toScanId(scanResult) + " has score: " |
| 231 | + score + " isCurrentNetwork network: " + isCurrentNetwork); |
| 232 | } |
| 233 | return score; |
| 234 | } |
| 235 | return null; |
| 236 | } |
| 237 | |
| 238 | /** Track an untrusted {@link ScanDetail}. */ |
| 239 | void trackUntrustedCandidate(ScanDetail scanDetail) { |
| 240 | ScanResult scanResult = scanDetail.getScanResult(); |
| 241 | Integer score = getNetworkScore(scanResult, false /* isCurrentNetwork */); |
| 242 | if (score != null && score > mHighScore) { |
| 243 | mHighScore = score; |
| 244 | mScanResultCandidate = scanResult; |
| 245 | mScanDetailCandidate = scanDetail; |
| 246 | mBestCandidateType = EXTERNAL_SCORED_UNTRUSTED_NETWORK; |
| 247 | debugLog(WifiNetworkSelector.toScanId(scanResult) |
| 248 | + " becomes the new untrusted candidate."); |
| 249 | } |
| 250 | } |
| 251 | |
| 252 | /** |
| 253 | * Track an untrusted {@link ScanResult} that already has a corresponding |
| 254 | * ephemeral {@link WifiConfiguration}. |
| 255 | */ |
| 256 | void trackUntrustedCandidate( |
| 257 | ScanResult scanResult, WifiConfiguration config, boolean isCurrentNetwork) { |
| 258 | Integer score = getNetworkScore(scanResult, isCurrentNetwork); |
| 259 | if (score != null && score > mHighScore) { |
| 260 | mHighScore = score; |
| 261 | mScanResultCandidate = scanResult; |
| 262 | mScanDetailCandidate = null; |
| 263 | mBestCandidateType = EXTERNAL_SCORED_UNTRUSTED_NETWORK; |
| 264 | mEphemeralConfig = config; |
| 265 | mWifiConfigManager.setNetworkCandidateScanResult(config.networkId, scanResult, 0); |
| 266 | debugLog(WifiNetworkSelector.toScanId(scanResult) |
| 267 | + " becomes the new untrusted candidate."); |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | /** Tracks a saved network that has been marked with useExternalScores */ |
| 272 | void trackExternallyScoredCandidate( |
| 273 | ScanResult scanResult, WifiConfiguration config, boolean isCurrentNetwork) { |
| 274 | // Always take the highest score. If there's a tie and an untrusted network is currently |
| 275 | // the best then pick the saved network. |
| 276 | Integer score = getNetworkScore(scanResult, isCurrentNetwork); |
| 277 | if (score != null |
| 278 | && (score > mHighScore |
| 279 | || (mBestCandidateType == EXTERNAL_SCORED_UNTRUSTED_NETWORK |
| 280 | && score == mHighScore))) { |
| 281 | mHighScore = score; |
| 282 | mSavedConfig = config; |
| 283 | mScanResultCandidate = scanResult; |
| 284 | mScanDetailCandidate = null; |
| 285 | mBestCandidateType = EXTERNAL_SCORED_SAVED_NETWORK; |
| 286 | mWifiConfigManager.setNetworkCandidateScanResult(config.networkId, scanResult, 0); |
| 287 | debugLog(WifiNetworkSelector.toScanId(scanResult) |
| 288 | + " becomes the new externally scored saved network candidate."); |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | /** Returns the best candidate network tracked by this {@link ScoreTracker}. */ |
| 293 | @Nullable |
| 294 | WifiConfiguration getCandidateConfiguration( |
| 295 | @NonNull OnConnectableListener onConnectableListener) { |
| 296 | int candidateNetworkId = WifiConfiguration.INVALID_NETWORK_ID; |
| 297 | switch (mBestCandidateType) { |
| 298 | case ScoreTracker.EXTERNAL_SCORED_UNTRUSTED_NETWORK: |
| 299 | if (mEphemeralConfig != null) { |
| 300 | candidateNetworkId = mEphemeralConfig.networkId; |
| 301 | mLocalLog.log(String.format("existing ephemeral candidate %s network ID:%d" |
| 302 | + ", meteredHint=%b", |
| 303 | WifiNetworkSelector.toScanId(mScanResultCandidate), |
| 304 | candidateNetworkId, |
| 305 | mEphemeralConfig.meteredHint)); |
| 306 | break; |
| 307 | } |
| 308 | Pair<Integer, String> scorerUidAndPackage = getActiveScorerUidAndPackage(); |
| 309 | if (scorerUidAndPackage == null) { |
| 310 | mLocalLog.log("Can't find active scorer uid and package"); |
| 311 | break; |
| 312 | } |
| 313 | |
| 314 | mEphemeralConfig = |
| 315 | ScanResultUtil.createNetworkFromScanResult(mScanResultCandidate); |
| 316 | // Mark this config as ephemeral so it isn't persisted. |
| 317 | mEphemeralConfig.ephemeral = true; |
| 318 | // Mark this network as untrusted. |
| 319 | mEphemeralConfig.trusted = false; |
| 320 | mEphemeralConfig.meteredHint = mScoreCache.getMeteredHint(mScanResultCandidate); |
| 321 | NetworkUpdateResult result = |
| 322 | mWifiConfigManager.addOrUpdateNetwork(mEphemeralConfig, |
| 323 | scorerUidAndPackage.first, scorerUidAndPackage.second); |
| 324 | if (!result.isSuccess()) { |
| 325 | mLocalLog.log("Failed to add ephemeral network"); |
| 326 | break; |
| 327 | } |
| 328 | if (!mWifiConfigManager.updateNetworkSelectionStatus(result.getNetworkId(), |
| 329 | WifiConfiguration.NetworkSelectionStatus.DISABLED_NONE)) { |
| 330 | mLocalLog.log("Failed to make ephemeral network selectable"); |
| 331 | break; |
| 332 | } |
| 333 | candidateNetworkId = result.getNetworkId(); |
| 334 | if (mScanDetailCandidate == null) { |
| 335 | // This should never happen, but if it does, WNS will log a wtf. |
| 336 | // A message here might help with the diagnosis. |
| 337 | Log.e(TAG, "mScanDetailCandidate is null!"); |
| 338 | } |
| 339 | mWifiConfigManager.setNetworkCandidateScanResult(candidateNetworkId, |
| 340 | mScanResultCandidate, 0); |
| 341 | mLocalLog.log(String.format("new ephemeral candidate %s network ID:%d, " |
| 342 | + "meteredHint=%b", |
| 343 | WifiNetworkSelector.toScanId(mScanResultCandidate), |
| 344 | candidateNetworkId, |
| 345 | mEphemeralConfig.meteredHint)); |
| 346 | break; |
| 347 | case ScoreTracker.EXTERNAL_SCORED_SAVED_NETWORK: |
| 348 | candidateNetworkId = mSavedConfig.networkId; |
| 349 | mLocalLog.log(String.format("new saved network candidate %s network ID:%d", |
| 350 | WifiNetworkSelector.toScanId(mScanResultCandidate), |
| 351 | candidateNetworkId)); |
| 352 | break; |
| 353 | case ScoreTracker.EXTERNAL_SCORED_NONE: |
| 354 | default: |
| 355 | mLocalLog.log("ScoredNetworkNominator did not see any good candidates."); |
| 356 | break; |
| 357 | } |
| 358 | WifiConfiguration ans = mWifiConfigManager.getConfiguredNetwork( |
| 359 | candidateNetworkId); |
| 360 | if (ans != null && mScanDetailCandidate != null) { |
| 361 | // This is a newly created config, so we need to call onConnectable. |
| 362 | onConnectableListener.onConnectable(mScanDetailCandidate, ans); |
| 363 | } |
| 364 | return ans; |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | private void debugLog(String msg) { |
| 369 | if (DEBUG) { |
| 370 | mLocalLog.log(msg); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | @Override |
| 375 | public @NominatorId int getId() { |
| 376 | return NOMINATOR_ID_SCORED; |
| 377 | } |
| 378 | |
| 379 | @Override |
| 380 | public String getName() { |
| 381 | return TAG; |
| 382 | } |
| 383 | } |