The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 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; |
| 18 | |
| 19 | import android.content.BroadcastReceiver; |
| 20 | import android.content.ContentResolver; |
| 21 | import android.content.Context; |
| 22 | import android.content.Intent; |
| 23 | import android.content.IntentFilter; |
| 24 | import android.database.ContentObserver; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 25 | import android.net.ConnectivityManager; |
| 26 | import android.net.LinkProperties; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 27 | import android.net.NetworkInfo; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 28 | import android.net.wifi.ScanResult; |
| 29 | import android.net.wifi.WifiInfo; |
| 30 | import android.net.wifi.WifiManager; |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 31 | import android.net.Uri; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 32 | import android.os.Handler; |
| 33 | import android.os.Looper; |
| 34 | import android.os.Message; |
| 35 | import android.provider.Settings; |
| 36 | import android.text.TextUtils; |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 37 | import android.util.Slog; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 38 | |
| 39 | import java.io.IOException; |
| 40 | import java.net.DatagramPacket; |
| 41 | import java.net.DatagramSocket; |
| 42 | import java.net.InetAddress; |
| 43 | import java.net.SocketException; |
| 44 | import java.net.SocketTimeoutException; |
| 45 | import java.net.UnknownHostException; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 46 | import java.util.Collection; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 47 | import java.util.List; |
| 48 | import java.util.Random; |
| 49 | |
| 50 | /** |
| 51 | * {@link WifiWatchdogService} monitors the initial connection to a Wi-Fi |
| 52 | * network with multiple access points. After the framework successfully |
| 53 | * connects to an access point, the watchdog verifies whether the DNS server is |
| 54 | * reachable. If not, the watchdog blacklists the current access point, leading |
| 55 | * to a connection on another access point within the same network. |
| 56 | * <p> |
| 57 | * The watchdog has a few safeguards: |
| 58 | * <ul> |
| 59 | * <li>Only monitor networks with multiple access points |
| 60 | * <li>Only check at most {@link #getMaxApChecks()} different access points |
| 61 | * within the network before giving up |
| 62 | * <p> |
| 63 | * The watchdog checks for connectivity on an access point by ICMP pinging the |
| 64 | * DNS. There are settings that allow disabling the watchdog, or tweaking the |
| 65 | * acceptable packet loss (and other various parameters). |
| 66 | * <p> |
| 67 | * The core logic of the watchdog is done on the main watchdog thread. Wi-Fi |
| 68 | * callbacks can come in on other threads, so we must queue messages to the main |
| 69 | * watchdog thread's handler. Most (if not all) state is only written to from |
| 70 | * the main thread. |
| 71 | * |
| 72 | * {@hide} |
| 73 | */ |
| 74 | public class WifiWatchdogService { |
| 75 | private static final String TAG = "WifiWatchdogService"; |
Joe Onorato | 43a1765 | 2011-04-06 19:22:23 -0700 | [diff] [blame] | 76 | private static final boolean V = false || false; |
| 77 | private static final boolean D = true || false; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 78 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 79 | private Context mContext; |
| 80 | private ContentResolver mContentResolver; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 81 | private WifiManager mWifiManager; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 82 | private ConnectivityManager mConnectivityManager; |
| 83 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 84 | /** |
| 85 | * The main watchdog thread. |
| 86 | */ |
| 87 | private WifiWatchdogThread mThread; |
| 88 | /** |
| 89 | * The handler for the main watchdog thread. |
| 90 | */ |
| 91 | private WifiWatchdogHandler mHandler; |
| 92 | |
Irfan Sheriff | 7b00978 | 2010-03-11 16:37:45 -0800 | [diff] [blame] | 93 | private ContentObserver mContentObserver; |
| 94 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 95 | /** |
| 96 | * The current watchdog state. Only written from the main thread! |
| 97 | */ |
| 98 | private WatchdogState mState = WatchdogState.IDLE; |
| 99 | /** |
| 100 | * The SSID of the network that the watchdog is currently monitoring. Only |
| 101 | * touched in the main thread! |
| 102 | */ |
| 103 | private String mSsid; |
| 104 | /** |
| 105 | * The number of access points in the current network ({@link #mSsid}) that |
| 106 | * have been checked. Only touched in the main thread! |
| 107 | */ |
| 108 | private int mNumApsChecked; |
| 109 | /** Whether the current AP check should be canceled. */ |
| 110 | private boolean mShouldCancel; |
| 111 | |
Irfan Sheriff | 0d25534 | 2010-07-28 09:35:20 -0700 | [diff] [blame] | 112 | WifiWatchdogService(Context context) { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 113 | mContext = context; |
| 114 | mContentResolver = context.getContentResolver(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 115 | mWifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE); |
| 116 | |
| 117 | createThread(); |
| 118 | |
| 119 | // The content observer to listen needs a handler, which createThread creates |
| 120 | registerForSettingsChanges(); |
| 121 | if (isWatchdogEnabled()) { |
| 122 | registerForWifiBroadcasts(); |
| 123 | } |
| 124 | |
| 125 | if (V) { |
| 126 | myLogV("WifiWatchdogService: Created"); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * Observes the watchdog on/off setting, and takes action when changed. |
| 132 | */ |
| 133 | private void registerForSettingsChanges() { |
| 134 | ContentResolver contentResolver = mContext.getContentResolver(); |
| 135 | contentResolver.registerContentObserver( |
| 136 | Settings.Secure.getUriFor(Settings.Secure.WIFI_WATCHDOG_ON), false, |
Irfan Sheriff | 7b00978 | 2010-03-11 16:37:45 -0800 | [diff] [blame] | 137 | mContentObserver = new ContentObserver(mHandler) { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 138 | @Override |
| 139 | public void onChange(boolean selfChange) { |
| 140 | if (isWatchdogEnabled()) { |
| 141 | registerForWifiBroadcasts(); |
| 142 | } else { |
| 143 | unregisterForWifiBroadcasts(); |
| 144 | if (mHandler != null) { |
| 145 | mHandler.disableWatchdog(); |
| 146 | } |
| 147 | } |
| 148 | } |
| 149 | }); |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_ON |
| 154 | */ |
| 155 | private boolean isWatchdogEnabled() { |
| 156 | return Settings.Secure.getInt(mContentResolver, Settings.Secure.WIFI_WATCHDOG_ON, 1) == 1; |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_AP_COUNT |
| 161 | */ |
| 162 | private int getApCount() { |
| 163 | return Settings.Secure.getInt(mContentResolver, |
| 164 | Settings.Secure.WIFI_WATCHDOG_AP_COUNT, 2); |
| 165 | } |
| 166 | |
| 167 | /** |
| 168 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_INITIAL_IGNORED_PING_COUNT |
| 169 | */ |
| 170 | private int getInitialIgnoredPingCount() { |
| 171 | return Settings.Secure.getInt(mContentResolver, |
| 172 | Settings.Secure.WIFI_WATCHDOG_INITIAL_IGNORED_PING_COUNT , 2); |
| 173 | } |
| 174 | |
| 175 | /** |
| 176 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_PING_COUNT |
| 177 | */ |
| 178 | private int getPingCount() { |
| 179 | return Settings.Secure.getInt(mContentResolver, |
| 180 | Settings.Secure.WIFI_WATCHDOG_PING_COUNT, 4); |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_PING_TIMEOUT_MS |
| 185 | */ |
| 186 | private int getPingTimeoutMs() { |
| 187 | return Settings.Secure.getInt(mContentResolver, |
| 188 | Settings.Secure.WIFI_WATCHDOG_PING_TIMEOUT_MS, 500); |
| 189 | } |
| 190 | |
| 191 | /** |
| 192 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_PING_DELAY_MS |
| 193 | */ |
| 194 | private int getPingDelayMs() { |
| 195 | return Settings.Secure.getInt(mContentResolver, |
| 196 | Settings.Secure.WIFI_WATCHDOG_PING_DELAY_MS, 250); |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_ACCEPTABLE_PACKET_LOSS_PERCENTAGE |
| 201 | */ |
| 202 | private int getAcceptablePacketLossPercentage() { |
| 203 | return Settings.Secure.getInt(mContentResolver, |
| 204 | Settings.Secure.WIFI_WATCHDOG_ACCEPTABLE_PACKET_LOSS_PERCENTAGE, 25); |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_MAX_AP_CHECKS |
| 209 | */ |
| 210 | private int getMaxApChecks() { |
| 211 | return Settings.Secure.getInt(mContentResolver, |
| 212 | Settings.Secure.WIFI_WATCHDOG_MAX_AP_CHECKS, 7); |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_BACKGROUND_CHECK_ENABLED |
| 217 | */ |
| 218 | private boolean isBackgroundCheckEnabled() { |
| 219 | return Settings.Secure.getInt(mContentResolver, |
| 220 | Settings.Secure.WIFI_WATCHDOG_BACKGROUND_CHECK_ENABLED, 1) == 1; |
| 221 | } |
| 222 | |
| 223 | /** |
| 224 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_BACKGROUND_CHECK_DELAY_MS |
| 225 | */ |
| 226 | private int getBackgroundCheckDelayMs() { |
| 227 | return Settings.Secure.getInt(mContentResolver, |
| 228 | Settings.Secure.WIFI_WATCHDOG_BACKGROUND_CHECK_DELAY_MS, 60000); |
| 229 | } |
| 230 | |
| 231 | /** |
| 232 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_BACKGROUND_CHECK_TIMEOUT_MS |
| 233 | */ |
| 234 | private int getBackgroundCheckTimeoutMs() { |
| 235 | return Settings.Secure.getInt(mContentResolver, |
| 236 | Settings.Secure.WIFI_WATCHDOG_BACKGROUND_CHECK_TIMEOUT_MS, 1000); |
| 237 | } |
| 238 | |
| 239 | /** |
| 240 | * @see android.provider.Settings.Secure#WIFI_WATCHDOG_WATCH_LIST |
| 241 | * @return the comma-separated list of SSIDs |
| 242 | */ |
| 243 | private String getWatchList() { |
| 244 | return Settings.Secure.getString(mContentResolver, |
| 245 | Settings.Secure.WIFI_WATCHDOG_WATCH_LIST); |
| 246 | } |
| 247 | |
| 248 | /** |
| 249 | * Registers to receive the necessary Wi-Fi broadcasts. |
| 250 | */ |
| 251 | private void registerForWifiBroadcasts() { |
| 252 | IntentFilter intentFilter = new IntentFilter(); |
| 253 | intentFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 254 | intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION); |
| 255 | mContext.registerReceiver(mReceiver, intentFilter); |
| 256 | } |
| 257 | |
| 258 | /** |
| 259 | * Unregisters from receiving the Wi-Fi broadcasts. |
| 260 | */ |
| 261 | private void unregisterForWifiBroadcasts() { |
| 262 | mContext.unregisterReceiver(mReceiver); |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * Creates the main watchdog thread, including waiting for the handler to be |
| 267 | * created. |
| 268 | */ |
| 269 | private void createThread() { |
| 270 | mThread = new WifiWatchdogThread(); |
| 271 | mThread.start(); |
| 272 | waitForHandlerCreation(); |
| 273 | } |
| 274 | |
| 275 | /** |
Irfan Sheriff | 7b00978 | 2010-03-11 16:37:45 -0800 | [diff] [blame] | 276 | * Unregister broadcasts and quit the watchdog thread |
| 277 | */ |
Irfan Sheriff | a2a1b91 | 2010-06-07 09:03:04 -0700 | [diff] [blame] | 278 | //TODO: Change back to running WWS when needed |
| 279 | // private void quit() { |
| 280 | // unregisterForWifiBroadcasts(); |
| 281 | // mContext.getContentResolver().unregisterContentObserver(mContentObserver); |
| 282 | // mHandler.removeAllActions(); |
| 283 | // mHandler.getLooper().quit(); |
| 284 | // } |
Irfan Sheriff | 7b00978 | 2010-03-11 16:37:45 -0800 | [diff] [blame] | 285 | |
| 286 | /** |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 287 | * Waits for the main watchdog thread to create the handler. |
| 288 | */ |
| 289 | private void waitForHandlerCreation() { |
| 290 | synchronized(this) { |
| 291 | while (mHandler == null) { |
| 292 | try { |
| 293 | // Wait for the handler to be set by the other thread |
| 294 | wait(); |
| 295 | } catch (InterruptedException e) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 296 | Slog.e(TAG, "Interrupted while waiting on handler."); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 297 | } |
| 298 | } |
| 299 | } |
| 300 | } |
| 301 | |
| 302 | // Utility methods |
| 303 | |
| 304 | /** |
| 305 | * Logs with the current thread. |
| 306 | */ |
| 307 | private static void myLogV(String message) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 308 | Slog.v(TAG, "(" + Thread.currentThread().getName() + ") " + message); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 309 | } |
| 310 | |
| 311 | private static void myLogD(String message) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 312 | Slog.d(TAG, "(" + Thread.currentThread().getName() + ") " + message); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 313 | } |
| 314 | |
| 315 | /** |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 316 | * Gets the first DNS of the current AP. |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 317 | * |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 318 | * @return The first DNS of the current AP. |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 319 | */ |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 320 | private InetAddress getDns() { |
| 321 | if (mConnectivityManager == null) { |
| 322 | mConnectivityManager = (ConnectivityManager)mContext.getSystemService( |
| 323 | Context.CONNECTIVITY_SERVICE); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 324 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 325 | |
| 326 | LinkProperties linkProperties = mConnectivityManager.getLinkProperties( |
| 327 | ConnectivityManager.TYPE_WIFI); |
| 328 | if (linkProperties == null) return null; |
| 329 | |
| 330 | Collection<InetAddress> dnses = linkProperties.getDnses(); |
| 331 | if (dnses == null || dnses.size() == 0) return null; |
| 332 | |
| 333 | return dnses.iterator().next(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 334 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 335 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 336 | /** |
| 337 | * Checks whether the DNS can be reached using multiple attempts according |
| 338 | * to the current setting values. |
| 339 | * |
| 340 | * @return Whether the DNS is reachable |
| 341 | */ |
| 342 | private boolean checkDnsConnectivity() { |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 343 | InetAddress dns = getDns(); |
| 344 | if (dns == null) { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 345 | if (V) { |
| 346 | myLogV("checkDnsConnectivity: Invalid DNS, returning false"); |
| 347 | } |
| 348 | return false; |
| 349 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 350 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 351 | if (V) { |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 352 | myLogV("checkDnsConnectivity: Checking " + dns.getHostAddress() + " for connectivity"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 353 | } |
| 354 | |
| 355 | int numInitialIgnoredPings = getInitialIgnoredPingCount(); |
| 356 | int numPings = getPingCount(); |
| 357 | int pingDelay = getPingDelayMs(); |
| 358 | int acceptableLoss = getAcceptablePacketLossPercentage(); |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 359 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 360 | /** See {@link Secure#WIFI_WATCHDOG_INITIAL_IGNORED_PING_COUNT} */ |
| 361 | int ignoredPingCounter = 0; |
| 362 | int pingCounter = 0; |
| 363 | int successCounter = 0; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 364 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 365 | // No connectivity check needed |
| 366 | if (numPings == 0) { |
| 367 | return true; |
| 368 | } |
| 369 | |
| 370 | // Do the initial pings that we ignore |
| 371 | for (; ignoredPingCounter < numInitialIgnoredPings; ignoredPingCounter++) { |
| 372 | if (shouldCancel()) return false; |
| 373 | |
| 374 | boolean dnsAlive = DnsPinger.isDnsReachable(dns, getPingTimeoutMs()); |
| 375 | if (dnsAlive) { |
| 376 | /* |
| 377 | * Successful "ignored" pings are *not* ignored (they count in the total number |
| 378 | * of pings), but failures are really ignored. |
| 379 | */ |
| 380 | pingCounter++; |
| 381 | successCounter++; |
| 382 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 383 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 384 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 385 | Slog.v(TAG, (dnsAlive ? " +" : " Ignored: -")); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 386 | } |
| 387 | |
| 388 | if (shouldCancel()) return false; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 389 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 390 | try { |
| 391 | Thread.sleep(pingDelay); |
| 392 | } catch (InterruptedException e) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 393 | Slog.w(TAG, "Interrupted while pausing between pings", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 394 | } |
| 395 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 396 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 397 | // Do the pings that we use to measure packet loss |
| 398 | for (; pingCounter < numPings; pingCounter++) { |
| 399 | if (shouldCancel()) return false; |
| 400 | |
| 401 | if (DnsPinger.isDnsReachable(dns, getPingTimeoutMs())) { |
| 402 | successCounter++; |
| 403 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 404 | Slog.v(TAG, " +"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 405 | } |
| 406 | } else { |
| 407 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 408 | Slog.v(TAG, " -"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 409 | } |
| 410 | } |
| 411 | |
| 412 | if (shouldCancel()) return false; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 413 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 414 | try { |
| 415 | Thread.sleep(pingDelay); |
| 416 | } catch (InterruptedException e) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 417 | Slog.w(TAG, "Interrupted while pausing between pings", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 418 | } |
| 419 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 420 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 421 | int packetLossPercentage = 100 * (numPings - successCounter) / numPings; |
| 422 | if (D) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 423 | Slog.d(TAG, packetLossPercentage |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 424 | + "% packet loss (acceptable is " + acceptableLoss + "%)"); |
| 425 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 426 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 427 | return !shouldCancel() && (packetLossPercentage <= acceptableLoss); |
| 428 | } |
| 429 | |
| 430 | private boolean backgroundCheckDnsConnectivity() { |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 431 | InetAddress dns = getDns(); |
| 432 | |
| 433 | if (dns == null) { |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 434 | if (V) { |
| 435 | myLogV("backgroundCheckDnsConnectivity: DNS is empty, returning false"); |
| 436 | } |
| 437 | return false; |
| 438 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 439 | |
| 440 | if (false && V) { |
| 441 | myLogV("backgroundCheckDnsConnectivity: Background checking " + |
| 442 | dns.getHostAddress() + " for connectivity"); |
| 443 | } |
| 444 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 445 | return DnsPinger.isDnsReachable(dns, getBackgroundCheckTimeoutMs()); |
| 446 | } |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 447 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 448 | /** |
| 449 | * Signals the current action to cancel. |
| 450 | */ |
| 451 | private void cancelCurrentAction() { |
| 452 | mShouldCancel = true; |
| 453 | } |
| 454 | |
| 455 | /** |
| 456 | * Helper to check whether to cancel. |
| 457 | * |
| 458 | * @return Whether to cancel processing the action. |
| 459 | */ |
| 460 | private boolean shouldCancel() { |
| 461 | if (V && mShouldCancel) { |
| 462 | myLogV("shouldCancel: Cancelling"); |
| 463 | } |
| 464 | |
| 465 | return mShouldCancel; |
| 466 | } |
| 467 | |
| 468 | // Wi-Fi initiated callbacks (could be executed in another thread) |
| 469 | |
| 470 | /** |
| 471 | * Called when connected to an AP (this can be the next AP in line, or |
| 472 | * it can be a completely different network). |
| 473 | * |
| 474 | * @param ssid The SSID of the access point. |
| 475 | * @param bssid The BSSID of the access point. |
| 476 | */ |
| 477 | private void onConnected(String ssid, String bssid) { |
| 478 | if (V) { |
| 479 | myLogV("onConnected: SSID: " + ssid + ", BSSID: " + bssid); |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * The current action being processed by the main watchdog thread is now |
| 484 | * stale, so cancel it. |
| 485 | */ |
| 486 | cancelCurrentAction(); |
| 487 | |
| 488 | if ((mSsid == null) || !mSsid.equals(ssid)) { |
| 489 | /* |
| 490 | * This is a different network than what the main watchdog thread is |
| 491 | * processing, dispatch the network change message on the main thread. |
| 492 | */ |
| 493 | mHandler.dispatchNetworkChanged(ssid); |
| 494 | } |
| 495 | |
| 496 | if (requiresWatchdog(ssid, bssid)) { |
| 497 | if (D) { |
| 498 | myLogD(ssid + " (" + bssid + ") requires the watchdog"); |
| 499 | } |
| 500 | |
| 501 | // This access point requires a watchdog, so queue the check on the main thread |
| 502 | mHandler.checkAp(new AccessPoint(ssid, bssid)); |
| 503 | |
| 504 | } else { |
| 505 | if (D) { |
| 506 | myLogD(ssid + " (" + bssid + ") does not require the watchdog"); |
| 507 | } |
| 508 | |
| 509 | // This access point does not require a watchdog, so queue idle on the main thread |
| 510 | mHandler.idle(); |
| 511 | } |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 512 | mHandler.checkWalledGarden(ssid); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 513 | } |
| 514 | |
| 515 | /** |
| 516 | * Called when Wi-Fi is enabled. |
| 517 | */ |
| 518 | private void onEnabled() { |
| 519 | cancelCurrentAction(); |
| 520 | // Queue a hard-reset of the state on the main thread |
| 521 | mHandler.reset(); |
| 522 | } |
| 523 | |
| 524 | /** |
| 525 | * Called when disconnected (or some other event similar to being disconnected). |
| 526 | */ |
| 527 | private void onDisconnected() { |
| 528 | if (V) { |
| 529 | myLogV("onDisconnected"); |
| 530 | } |
| 531 | |
| 532 | /* |
| 533 | * Disconnected from an access point, the action being processed by the |
| 534 | * watchdog thread is now stale, so cancel it. |
| 535 | */ |
| 536 | cancelCurrentAction(); |
| 537 | // Dispatch the disconnected to the main watchdog thread |
| 538 | mHandler.dispatchDisconnected(); |
| 539 | // Queue the action to go idle |
| 540 | mHandler.idle(); |
| 541 | } |
| 542 | |
| 543 | /** |
| 544 | * Checks whether an access point requires watchdog monitoring. |
| 545 | * |
| 546 | * @param ssid The SSID of the access point. |
| 547 | * @param bssid The BSSID of the access point. |
| 548 | * @return Whether the access point/network should be monitored by the |
| 549 | * watchdog. |
| 550 | */ |
| 551 | private boolean requiresWatchdog(String ssid, String bssid) { |
| 552 | if (V) { |
| 553 | myLogV("requiresWatchdog: SSID: " + ssid + ", BSSID: " + bssid); |
| 554 | } |
| 555 | |
| 556 | WifiInfo info = null; |
| 557 | if (ssid == null) { |
| 558 | /* |
| 559 | * This is called from a Wi-Fi callback, so assume the WifiInfo does |
| 560 | * not have stale data. |
| 561 | */ |
| 562 | info = mWifiManager.getConnectionInfo(); |
| 563 | ssid = info.getSSID(); |
| 564 | if (ssid == null) { |
| 565 | // It's still null, give up |
| 566 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 567 | Slog.v(TAG, " Invalid SSID, returning false"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 568 | } |
| 569 | return false; |
| 570 | } |
| 571 | } |
| 572 | |
| 573 | if (TextUtils.isEmpty(bssid)) { |
| 574 | // Similar as above |
| 575 | if (info == null) { |
| 576 | info = mWifiManager.getConnectionInfo(); |
| 577 | } |
| 578 | bssid = info.getBSSID(); |
| 579 | if (TextUtils.isEmpty(bssid)) { |
| 580 | // It's still null, give up |
| 581 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 582 | Slog.v(TAG, " Invalid BSSID, returning false"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 583 | } |
| 584 | return false; |
| 585 | } |
| 586 | } |
| 587 | |
| 588 | if (!isOnWatchList(ssid)) { |
| 589 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 590 | Slog.v(TAG, " SSID not on watch list, returning false"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 591 | } |
| 592 | return false; |
| 593 | } |
| 594 | |
| 595 | // The watchdog only monitors networks with multiple APs |
| 596 | if (!hasRequiredNumberOfAps(ssid)) { |
| 597 | return false; |
| 598 | } |
| 599 | |
| 600 | return true; |
| 601 | } |
| 602 | |
| 603 | private boolean isOnWatchList(String ssid) { |
| 604 | String watchList; |
| 605 | |
| 606 | if (ssid == null || (watchList = getWatchList()) == null) { |
| 607 | return false; |
| 608 | } |
| 609 | |
| 610 | String[] list = watchList.split(" *, *"); |
| 611 | |
| 612 | for (String name : list) { |
| 613 | if (ssid.equals(name)) { |
| 614 | return true; |
| 615 | } |
| 616 | } |
| 617 | |
| 618 | return false; |
| 619 | } |
| 620 | |
| 621 | /** |
| 622 | * Checks if the current scan results have multiple access points with an SSID. |
| 623 | * |
| 624 | * @param ssid The SSID to check. |
| 625 | * @return Whether the SSID has multiple access points. |
| 626 | */ |
| 627 | private boolean hasRequiredNumberOfAps(String ssid) { |
| 628 | List<ScanResult> results = mWifiManager.getScanResults(); |
| 629 | if (results == null) { |
| 630 | if (V) { |
| 631 | myLogV("hasRequiredNumberOfAps: Got null scan results, returning false"); |
| 632 | } |
| 633 | return false; |
| 634 | } |
| 635 | |
| 636 | int numApsRequired = getApCount(); |
| 637 | int numApsFound = 0; |
| 638 | int resultsSize = results.size(); |
| 639 | for (int i = 0; i < resultsSize; i++) { |
| 640 | ScanResult result = results.get(i); |
| 641 | if (result == null) continue; |
| 642 | if (result.SSID == null) continue; |
| 643 | |
| 644 | if (result.SSID.equals(ssid)) { |
| 645 | numApsFound++; |
| 646 | |
| 647 | if (numApsFound >= numApsRequired) { |
| 648 | if (V) { |
| 649 | myLogV("hasRequiredNumberOfAps: SSID: " + ssid + ", returning true"); |
| 650 | } |
| 651 | return true; |
| 652 | } |
| 653 | } |
| 654 | } |
| 655 | |
| 656 | if (V) { |
| 657 | myLogV("hasRequiredNumberOfAps: SSID: " + ssid + ", returning false"); |
| 658 | } |
| 659 | return false; |
| 660 | } |
| 661 | |
| 662 | // Watchdog logic (assume all of these methods will be in our main thread) |
| 663 | |
| 664 | /** |
| 665 | * Handles a Wi-Fi network change (for example, from networkA to networkB). |
| 666 | */ |
| 667 | private void handleNetworkChanged(String ssid) { |
| 668 | // Set the SSID being monitored to the new SSID |
| 669 | mSsid = ssid; |
| 670 | // Set various state to that when being idle |
| 671 | setIdleState(true); |
| 672 | } |
| 673 | |
| 674 | /** |
| 675 | * Handles checking whether an AP is a "good" AP. If not, it will be blacklisted. |
| 676 | * |
| 677 | * @param ap The access point to check. |
| 678 | */ |
| 679 | private void handleCheckAp(AccessPoint ap) { |
| 680 | // Reset the cancel state since this is the entry point of this action |
| 681 | mShouldCancel = false; |
| 682 | |
| 683 | if (V) { |
| 684 | myLogV("handleCheckAp: AccessPoint: " + ap); |
| 685 | } |
| 686 | |
| 687 | // Make sure we are not sleeping |
| 688 | if (mState == WatchdogState.SLEEP) { |
| 689 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 690 | Slog.v(TAG, " Sleeping (in " + mSsid + "), so returning"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 691 | } |
| 692 | return; |
| 693 | } |
| 694 | |
| 695 | mState = WatchdogState.CHECKING_AP; |
| 696 | |
| 697 | /* |
| 698 | * Checks to make sure we haven't exceeded the max number of checks |
| 699 | * we're allowed per network |
| 700 | */ |
| 701 | mNumApsChecked++; |
| 702 | if (mNumApsChecked > getMaxApChecks()) { |
| 703 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 704 | Slog.v(TAG, " Passed the max attempts (" + getMaxApChecks() |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 705 | + "), going to sleep for " + mSsid); |
| 706 | } |
| 707 | mHandler.sleep(mSsid); |
| 708 | return; |
| 709 | } |
| 710 | |
| 711 | // Do the check |
| 712 | boolean isApAlive = checkDnsConnectivity(); |
| 713 | |
| 714 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 715 | Slog.v(TAG, " Is it alive: " + isApAlive); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 716 | } |
| 717 | |
| 718 | // Take action based on results |
| 719 | if (isApAlive) { |
| 720 | handleApAlive(ap); |
| 721 | } else { |
| 722 | handleApUnresponsive(ap); |
| 723 | } |
| 724 | } |
| 725 | |
| 726 | /** |
| 727 | * Handles the case when an access point is alive. |
| 728 | * |
| 729 | * @param ap The access point. |
| 730 | */ |
| 731 | private void handleApAlive(AccessPoint ap) { |
| 732 | // Check whether we are stale and should cancel |
| 733 | if (shouldCancel()) return; |
| 734 | // We're satisfied with this AP, so go idle |
| 735 | setIdleState(false); |
| 736 | |
| 737 | if (D) { |
| 738 | myLogD("AP is alive: " + ap.toString()); |
| 739 | } |
| 740 | |
| 741 | // Queue the next action to be a background check |
| 742 | mHandler.backgroundCheckAp(ap); |
| 743 | } |
| 744 | |
| 745 | /** |
| 746 | * Handles an unresponsive AP by blacklisting it. |
| 747 | * |
| 748 | * @param ap The access point. |
| 749 | */ |
| 750 | private void handleApUnresponsive(AccessPoint ap) { |
| 751 | // Check whether we are stale and should cancel |
| 752 | if (shouldCancel()) return; |
| 753 | // This AP is "bad", switch to another |
| 754 | mState = WatchdogState.SWITCHING_AP; |
| 755 | |
| 756 | if (D) { |
| 757 | myLogD("AP is dead: " + ap.toString()); |
| 758 | } |
| 759 | |
| 760 | // Black list this "bad" AP, this will cause an attempt to connect to another |
| 761 | blacklistAp(ap.bssid); |
Irfan Sheriff | 0049a1b | 2010-01-14 12:37:49 -0800 | [diff] [blame] | 762 | // Initiate an association to an alternate AP |
Irfan Sheriff | 0d25534 | 2010-07-28 09:35:20 -0700 | [diff] [blame] | 763 | mWifiManager.reassociate(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 764 | } |
| 765 | |
| 766 | private void blacklistAp(String bssid) { |
| 767 | if (TextUtils.isEmpty(bssid)) { |
| 768 | return; |
| 769 | } |
| 770 | |
| 771 | // Before taking action, make sure we should not cancel our processing |
| 772 | if (shouldCancel()) return; |
| 773 | |
Irfan Sheriff | 0d25534 | 2010-07-28 09:35:20 -0700 | [diff] [blame] | 774 | mWifiManager.addToBlacklist(bssid); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 775 | |
| 776 | if (D) { |
| 777 | myLogD("Blacklisting " + bssid); |
| 778 | } |
| 779 | } |
| 780 | |
| 781 | /** |
| 782 | * Handles a single background check. If it fails, it should trigger a |
| 783 | * normal check. If it succeeds, it should queue another background check. |
| 784 | * |
| 785 | * @param ap The access point to do a background check for. If this is no |
| 786 | * longer the current AP, it is okay to return without any |
| 787 | * processing. |
| 788 | */ |
| 789 | private void handleBackgroundCheckAp(AccessPoint ap) { |
| 790 | // Reset the cancel state since this is the entry point of this action |
| 791 | mShouldCancel = false; |
| 792 | |
| 793 | if (false && V) { |
| 794 | myLogV("handleBackgroundCheckAp: AccessPoint: " + ap); |
| 795 | } |
| 796 | |
| 797 | // Make sure we are not sleeping |
| 798 | if (mState == WatchdogState.SLEEP) { |
| 799 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 800 | Slog.v(TAG, " handleBackgroundCheckAp: Sleeping (in " + mSsid + "), so returning"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 801 | } |
| 802 | return; |
| 803 | } |
| 804 | |
| 805 | // Make sure the AP we're supposed to be background checking is still the active one |
| 806 | WifiInfo info = mWifiManager.getConnectionInfo(); |
| 807 | if (info.getSSID() == null || !info.getSSID().equals(ap.ssid)) { |
| 808 | if (V) { |
| 809 | myLogV("handleBackgroundCheckAp: We are no longer connected to " |
| 810 | + ap + ", and instead are on " + info); |
| 811 | } |
| 812 | return; |
| 813 | } |
| 814 | |
| 815 | if (info.getBSSID() == null || !info.getBSSID().equals(ap.bssid)) { |
| 816 | if (V) { |
| 817 | myLogV("handleBackgroundCheckAp: We are no longer connected to " |
| 818 | + ap + ", and instead are on " + info); |
| 819 | } |
| 820 | return; |
| 821 | } |
| 822 | |
| 823 | // Do the check |
| 824 | boolean isApAlive = backgroundCheckDnsConnectivity(); |
| 825 | |
| 826 | if (V && !isApAlive) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 827 | Slog.v(TAG, " handleBackgroundCheckAp: Is it alive: " + isApAlive); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 828 | } |
| 829 | |
| 830 | if (shouldCancel()) { |
| 831 | return; |
| 832 | } |
| 833 | |
| 834 | // Take action based on results |
| 835 | if (isApAlive) { |
| 836 | // Queue another background check |
| 837 | mHandler.backgroundCheckAp(ap); |
| 838 | |
| 839 | } else { |
| 840 | if (D) { |
| 841 | myLogD("Background check failed for " + ap.toString()); |
| 842 | } |
| 843 | |
| 844 | // Queue a normal check, so it can take proper action |
| 845 | mHandler.checkAp(ap); |
| 846 | } |
| 847 | } |
| 848 | |
| 849 | /** |
| 850 | * Handles going to sleep for this network. Going to sleep means we will not |
| 851 | * monitor this network anymore. |
| 852 | * |
| 853 | * @param ssid The network that will not be monitored anymore. |
| 854 | */ |
| 855 | private void handleSleep(String ssid) { |
| 856 | // Make sure the network we're trying to sleep in is still the current network |
| 857 | if (ssid != null && ssid.equals(mSsid)) { |
| 858 | mState = WatchdogState.SLEEP; |
| 859 | |
| 860 | if (D) { |
| 861 | myLogD("Going to sleep for " + ssid); |
| 862 | } |
| 863 | |
| 864 | /* |
| 865 | * Before deciding to go to sleep, we may have checked a few APs |
| 866 | * (and blacklisted them). Clear the blacklist so the AP with best |
| 867 | * signal is chosen. |
| 868 | */ |
Irfan Sheriff | 0d25534 | 2010-07-28 09:35:20 -0700 | [diff] [blame] | 869 | mWifiManager.clearBlacklist(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 870 | |
| 871 | if (V) { |
| 872 | myLogV("handleSleep: Set state to SLEEP and cleared blacklist"); |
| 873 | } |
| 874 | } |
| 875 | } |
| 876 | |
| 877 | /** |
| 878 | * Handles an access point disconnection. |
| 879 | */ |
| 880 | private void handleDisconnected() { |
| 881 | /* |
| 882 | * We purposefully do not change mSsid to null. This is to handle |
| 883 | * disconnected followed by connected better (even if there is some |
| 884 | * duration in between). For example, if the watchdog went to sleep in a |
| 885 | * network, and then the phone goes to sleep, when the phone wakes up we |
| 886 | * still want to be in the sleeping state. When the phone went to sleep, |
| 887 | * we would have gotten a disconnected event which would then set mSsid |
| 888 | * = null. This is bad, since the following connect would cause us to do |
| 889 | * the "network is good?" check all over again. */ |
| 890 | |
| 891 | /* |
| 892 | * Set the state as if we were idle (don't come out of sleep, only |
| 893 | * hard reset and network changed should do that. |
| 894 | */ |
| 895 | setIdleState(false); |
| 896 | } |
| 897 | |
| 898 | /** |
| 899 | * Handles going idle. Idle means we are satisfied with the current state of |
| 900 | * things, but if a new connection occurs we'll re-evaluate. |
| 901 | */ |
| 902 | private void handleIdle() { |
| 903 | // Reset the cancel state since this is the entry point for this action |
| 904 | mShouldCancel = false; |
| 905 | |
| 906 | if (V) { |
| 907 | myLogV("handleSwitchToIdle"); |
| 908 | } |
| 909 | |
| 910 | // If we're sleeping, don't do anything |
| 911 | if (mState == WatchdogState.SLEEP) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 912 | Slog.v(TAG, " Sleeping (in " + mSsid + "), so returning"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 913 | return; |
| 914 | } |
| 915 | |
| 916 | // Set the idle state |
| 917 | setIdleState(false); |
| 918 | |
| 919 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 920 | Slog.v(TAG, " Set state to IDLE"); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 921 | } |
| 922 | } |
| 923 | |
| 924 | /** |
| 925 | * Sets the state as if we are going idle. |
| 926 | */ |
| 927 | private void setIdleState(boolean forceIdleState) { |
| 928 | // Setting idle state does not kick us out of sleep unless the forceIdleState is set |
| 929 | if (forceIdleState || (mState != WatchdogState.SLEEP)) { |
| 930 | mState = WatchdogState.IDLE; |
| 931 | } |
| 932 | mNumApsChecked = 0; |
| 933 | } |
| 934 | |
| 935 | /** |
| 936 | * Handles a hard reset. A hard reset is rarely used, but when used it |
| 937 | * should revert anything done by the watchdog monitoring. |
| 938 | */ |
| 939 | private void handleReset() { |
Irfan Sheriff | 0d25534 | 2010-07-28 09:35:20 -0700 | [diff] [blame] | 940 | mWifiManager.clearBlacklist(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 941 | setIdleState(true); |
| 942 | } |
| 943 | |
| 944 | // Inner classes |
| 945 | |
| 946 | /** |
| 947 | * Possible states for the watchdog to be in. |
| 948 | */ |
| 949 | private static enum WatchdogState { |
| 950 | /** The watchdog is currently idle, but it is still responsive to future AP checks in this network. */ |
| 951 | IDLE, |
| 952 | /** The watchdog is sleeping, so it will not try any AP checks for the network. */ |
| 953 | SLEEP, |
| 954 | /** The watchdog is currently checking an AP for connectivity. */ |
| 955 | CHECKING_AP, |
| 956 | /** The watchdog is switching to another AP in the network. */ |
| 957 | SWITCHING_AP |
| 958 | } |
| 959 | |
| 960 | /** |
| 961 | * The main thread for the watchdog monitoring. This will be turned into a |
| 962 | * {@link Looper} thread. |
| 963 | */ |
| 964 | private class WifiWatchdogThread extends Thread { |
| 965 | WifiWatchdogThread() { |
| 966 | super("WifiWatchdogThread"); |
| 967 | } |
| 968 | |
| 969 | @Override |
| 970 | public void run() { |
| 971 | // Set this thread up so the handler will work on it |
| 972 | Looper.prepare(); |
| 973 | |
| 974 | synchronized(WifiWatchdogService.this) { |
| 975 | mHandler = new WifiWatchdogHandler(); |
| 976 | |
| 977 | // Notify that the handler has been created |
| 978 | WifiWatchdogService.this.notify(); |
| 979 | } |
| 980 | |
| 981 | // Listen for messages to the handler |
| 982 | Looper.loop(); |
| 983 | } |
| 984 | } |
| 985 | |
| 986 | /** |
| 987 | * The main thread's handler. There are 'actions', and just general |
| 988 | * 'messages'. There should only ever be one 'action' in the queue (aside |
| 989 | * from the one being processed, if any). There may be multiple messages in |
| 990 | * the queue. So, actions are replaced by more recent actions, where as |
| 991 | * messages will be executed for sure. Messages end up being used to just |
| 992 | * change some state, and not really take any action. |
| 993 | * <p> |
| 994 | * There is little logic inside this class, instead methods of the form |
| 995 | * "handle___" are called in the main {@link WifiWatchdogService}. |
| 996 | */ |
| 997 | private class WifiWatchdogHandler extends Handler { |
| 998 | /** Check whether the AP is "good". The object will be an {@link AccessPoint}. */ |
| 999 | static final int ACTION_CHECK_AP = 1; |
| 1000 | /** Go into the idle state. */ |
| 1001 | static final int ACTION_IDLE = 2; |
| 1002 | /** |
| 1003 | * Performs a periodic background check whether the AP is still "good". |
| 1004 | * The object will be an {@link AccessPoint}. |
| 1005 | */ |
| 1006 | static final int ACTION_BACKGROUND_CHECK_AP = 3; |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 1007 | /** Check whether the connection is a walled garden */ |
| 1008 | static final int ACTION_CHECK_WALLED_GARDEN = 4; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1009 | |
| 1010 | /** |
| 1011 | * Go to sleep for the current network. We are conservative with making |
| 1012 | * this a message rather than action. We want to make sure our main |
| 1013 | * thread sees this message, but if it were an action it could be |
| 1014 | * removed from the queue and replaced by another action. The main |
| 1015 | * thread will ensure when it sees the message that the state is still |
| 1016 | * valid for going to sleep. |
| 1017 | * <p> |
| 1018 | * For an explanation of sleep, see {@link android.provider.Settings.Secure#WIFI_WATCHDOG_MAX_AP_CHECKS}. |
| 1019 | */ |
| 1020 | static final int MESSAGE_SLEEP = 101; |
| 1021 | /** Disables the watchdog. */ |
| 1022 | static final int MESSAGE_DISABLE_WATCHDOG = 102; |
| 1023 | /** The network has changed. */ |
| 1024 | static final int MESSAGE_NETWORK_CHANGED = 103; |
| 1025 | /** The current access point has disconnected. */ |
| 1026 | static final int MESSAGE_DISCONNECTED = 104; |
| 1027 | /** Performs a hard-reset on the watchdog state. */ |
| 1028 | static final int MESSAGE_RESET = 105; |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 1029 | |
| 1030 | /* Walled garden detection */ |
| 1031 | private String mLastSsid; |
| 1032 | private long mLastTime; |
| 1033 | private final long MIN_WALLED_GARDEN_TEST_INTERVAL = 15 * 60 * 1000; //15 minutes |
| 1034 | |
| 1035 | void checkWalledGarden(String ssid) { |
| 1036 | sendMessage(obtainMessage(ACTION_CHECK_WALLED_GARDEN, ssid)); |
| 1037 | } |
| 1038 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1039 | void checkAp(AccessPoint ap) { |
| 1040 | removeAllActions(); |
| 1041 | sendMessage(obtainMessage(ACTION_CHECK_AP, ap)); |
| 1042 | } |
| 1043 | |
| 1044 | void backgroundCheckAp(AccessPoint ap) { |
| 1045 | if (!isBackgroundCheckEnabled()) return; |
| 1046 | |
| 1047 | removeAllActions(); |
| 1048 | sendMessageDelayed(obtainMessage(ACTION_BACKGROUND_CHECK_AP, ap), |
| 1049 | getBackgroundCheckDelayMs()); |
| 1050 | } |
| 1051 | |
| 1052 | void idle() { |
| 1053 | removeAllActions(); |
| 1054 | sendMessage(obtainMessage(ACTION_IDLE)); |
| 1055 | } |
| 1056 | |
| 1057 | void sleep(String ssid) { |
| 1058 | removeAllActions(); |
| 1059 | sendMessage(obtainMessage(MESSAGE_SLEEP, ssid)); |
| 1060 | } |
| 1061 | |
| 1062 | void disableWatchdog() { |
| 1063 | removeAllActions(); |
| 1064 | sendMessage(obtainMessage(MESSAGE_DISABLE_WATCHDOG)); |
| 1065 | } |
| 1066 | |
| 1067 | void dispatchNetworkChanged(String ssid) { |
| 1068 | removeAllActions(); |
| 1069 | sendMessage(obtainMessage(MESSAGE_NETWORK_CHANGED, ssid)); |
| 1070 | } |
| 1071 | |
| 1072 | void dispatchDisconnected() { |
| 1073 | removeAllActions(); |
| 1074 | sendMessage(obtainMessage(MESSAGE_DISCONNECTED)); |
| 1075 | } |
| 1076 | |
| 1077 | void reset() { |
| 1078 | removeAllActions(); |
| 1079 | sendMessage(obtainMessage(MESSAGE_RESET)); |
| 1080 | } |
| 1081 | |
| 1082 | private void removeAllActions() { |
| 1083 | removeMessages(ACTION_CHECK_AP); |
| 1084 | removeMessages(ACTION_IDLE); |
| 1085 | removeMessages(ACTION_BACKGROUND_CHECK_AP); |
| 1086 | } |
| 1087 | |
| 1088 | @Override |
| 1089 | public void handleMessage(Message msg) { |
| 1090 | switch (msg.what) { |
| 1091 | case MESSAGE_NETWORK_CHANGED: |
| 1092 | handleNetworkChanged((String) msg.obj); |
| 1093 | break; |
| 1094 | case ACTION_CHECK_AP: |
| 1095 | handleCheckAp((AccessPoint) msg.obj); |
| 1096 | break; |
| 1097 | case ACTION_BACKGROUND_CHECK_AP: |
| 1098 | handleBackgroundCheckAp((AccessPoint) msg.obj); |
| 1099 | break; |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 1100 | case ACTION_CHECK_WALLED_GARDEN: |
| 1101 | handleWalledGardenCheck((String) msg.obj); |
| 1102 | break; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1103 | case MESSAGE_SLEEP: |
| 1104 | handleSleep((String) msg.obj); |
| 1105 | break; |
| 1106 | case ACTION_IDLE: |
| 1107 | handleIdle(); |
| 1108 | break; |
| 1109 | case MESSAGE_DISABLE_WATCHDOG: |
| 1110 | handleIdle(); |
| 1111 | break; |
| 1112 | case MESSAGE_DISCONNECTED: |
| 1113 | handleDisconnected(); |
| 1114 | break; |
| 1115 | case MESSAGE_RESET: |
| 1116 | handleReset(); |
| 1117 | break; |
| 1118 | } |
| 1119 | } |
Irfan Sheriff | 2f5f4bc | 2011-05-02 11:43:28 -0700 | [diff] [blame] | 1120 | |
| 1121 | private boolean isWalledGardenConnection() { |
| 1122 | //One way to detect a walled garden is to see if multiple DNS queries |
| 1123 | //resolve to the same IP address |
| 1124 | try { |
| 1125 | String host1 = "www.google.com"; |
| 1126 | String host2 = "www.android.com"; |
| 1127 | String address1 = InetAddress.getByName(host1).getHostAddress(); |
| 1128 | String address2 = InetAddress.getByName(host2).getHostAddress(); |
| 1129 | if (address1.equals(address2)) return true; |
| 1130 | } catch (UnknownHostException e) { |
| 1131 | return false; |
| 1132 | } |
| 1133 | return false; |
| 1134 | } |
| 1135 | |
| 1136 | private void handleWalledGardenCheck(String ssid) { |
| 1137 | long currentTime = System.currentTimeMillis(); |
| 1138 | //Avoid a walled garden test on the same network if one was already done |
| 1139 | //within MIN_WALLED_GARDEN_TEST_INTERVAL. This will handle scenarios where |
| 1140 | //there are frequent network disconnections |
| 1141 | if (ssid.equals(mLastSsid) && |
| 1142 | (currentTime - mLastTime) < MIN_WALLED_GARDEN_TEST_INTERVAL) { |
| 1143 | return; |
| 1144 | } |
| 1145 | |
| 1146 | mLastTime = currentTime; |
| 1147 | mLastSsid = ssid; |
| 1148 | |
| 1149 | if (isWalledGardenConnection()) { |
| 1150 | Uri uri = Uri.parse("http://www.google.com"); |
| 1151 | Intent intent = new Intent(Intent.ACTION_VIEW, uri); |
| 1152 | intent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | |
| 1153 | Intent.FLAG_ACTIVITY_NEW_TASK); |
| 1154 | mContext.startActivity(intent); |
| 1155 | } |
| 1156 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1157 | } |
| 1158 | |
| 1159 | /** |
| 1160 | * Receives Wi-Fi broadcasts. |
| 1161 | * <p> |
| 1162 | * There is little logic in this class, instead methods of the form "on___" |
| 1163 | * are called in the {@link WifiWatchdogService}. |
| 1164 | */ |
| 1165 | private BroadcastReceiver mReceiver = new BroadcastReceiver() { |
| 1166 | |
| 1167 | @Override |
| 1168 | public void onReceive(Context context, Intent intent) { |
| 1169 | final String action = intent.getAction(); |
| 1170 | if (action.equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)) { |
| 1171 | handleNetworkStateChanged( |
| 1172 | (NetworkInfo) intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO)); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1173 | } else if (action.equals(WifiManager.WIFI_STATE_CHANGED_ACTION)) { |
| 1174 | handleWifiStateChanged(intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, |
| 1175 | WifiManager.WIFI_STATE_UNKNOWN)); |
| 1176 | } |
| 1177 | } |
| 1178 | |
| 1179 | private void handleNetworkStateChanged(NetworkInfo info) { |
| 1180 | if (V) { |
| 1181 | myLogV("Receiver.handleNetworkStateChanged: NetworkInfo: " |
| 1182 | + info); |
| 1183 | } |
| 1184 | |
| 1185 | switch (info.getState()) { |
| 1186 | case CONNECTED: |
| 1187 | WifiInfo wifiInfo = mWifiManager.getConnectionInfo(); |
| 1188 | if (wifiInfo.getSSID() == null || wifiInfo.getBSSID() == null) { |
| 1189 | if (V) { |
| 1190 | myLogV("handleNetworkStateChanged: Got connected event but SSID or BSSID are null. SSID: " |
| 1191 | + wifiInfo.getSSID() |
| 1192 | + ", BSSID: " |
| 1193 | + wifiInfo.getBSSID() + ", ignoring event"); |
| 1194 | } |
| 1195 | return; |
| 1196 | } |
| 1197 | onConnected(wifiInfo.getSSID(), wifiInfo.getBSSID()); |
| 1198 | break; |
| 1199 | |
| 1200 | case DISCONNECTED: |
| 1201 | onDisconnected(); |
| 1202 | break; |
| 1203 | } |
| 1204 | } |
| 1205 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1206 | private void handleWifiStateChanged(int wifiState) { |
| 1207 | if (wifiState == WifiManager.WIFI_STATE_DISABLED) { |
Irfan Sheriff | a2a1b91 | 2010-06-07 09:03:04 -0700 | [diff] [blame] | 1208 | onDisconnected(); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1209 | } else if (wifiState == WifiManager.WIFI_STATE_ENABLED) { |
| 1210 | onEnabled(); |
| 1211 | } |
| 1212 | } |
| 1213 | }; |
| 1214 | |
| 1215 | /** |
| 1216 | * Describes an access point by its SSID and BSSID. |
| 1217 | */ |
| 1218 | private static class AccessPoint { |
| 1219 | String ssid; |
| 1220 | String bssid; |
| 1221 | |
| 1222 | AccessPoint(String ssid, String bssid) { |
| 1223 | this.ssid = ssid; |
| 1224 | this.bssid = bssid; |
| 1225 | } |
| 1226 | |
| 1227 | private boolean hasNull() { |
| 1228 | return ssid == null || bssid == null; |
| 1229 | } |
| 1230 | |
| 1231 | @Override |
| 1232 | public boolean equals(Object o) { |
| 1233 | if (!(o instanceof AccessPoint)) return false; |
| 1234 | AccessPoint otherAp = (AccessPoint) o; |
| 1235 | boolean iHaveNull = hasNull(); |
| 1236 | // Either we both have a null, or our SSIDs and BSSIDs are equal |
| 1237 | return (iHaveNull && otherAp.hasNull()) || |
| 1238 | (otherAp.bssid != null && ssid.equals(otherAp.ssid) |
| 1239 | && bssid.equals(otherAp.bssid)); |
| 1240 | } |
| 1241 | |
| 1242 | @Override |
| 1243 | public int hashCode() { |
| 1244 | if (ssid == null || bssid == null) return 0; |
| 1245 | return ssid.hashCode() + bssid.hashCode(); |
| 1246 | } |
| 1247 | |
| 1248 | @Override |
| 1249 | public String toString() { |
| 1250 | return ssid + " (" + bssid + ")"; |
| 1251 | } |
| 1252 | } |
| 1253 | |
| 1254 | /** |
| 1255 | * Performs a simple DNS "ping" by sending a "server status" query packet to |
| 1256 | * the DNS server. As long as the server replies, we consider it a success. |
| 1257 | * <p> |
| 1258 | * We do not use a simple hostname lookup because that could be cached and |
| 1259 | * the API may not differentiate between a time out and a failure lookup |
| 1260 | * (which we really care about). |
| 1261 | */ |
| 1262 | private static class DnsPinger { |
| 1263 | |
| 1264 | /** Number of bytes for the query */ |
| 1265 | private static final int DNS_QUERY_BASE_SIZE = 33; |
| 1266 | |
| 1267 | /** The DNS port */ |
| 1268 | private static final int DNS_PORT = 53; |
| 1269 | |
| 1270 | /** Used to generate IDs */ |
| 1271 | private static Random sRandom = new Random(); |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1272 | |
| 1273 | static boolean isDnsReachable(InetAddress dnsAddress, int timeout) { |
Nick Kralevich | 929b485 | 2010-06-09 14:27:43 -0700 | [diff] [blame] | 1274 | DatagramSocket socket = null; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1275 | try { |
Nick Kralevich | 929b485 | 2010-06-09 14:27:43 -0700 | [diff] [blame] | 1276 | socket = new DatagramSocket(); |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1277 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1278 | // Set some socket properties |
| 1279 | socket.setSoTimeout(timeout); |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1280 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1281 | byte[] buf = new byte[DNS_QUERY_BASE_SIZE]; |
| 1282 | fillQuery(buf); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1283 | |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1284 | // Send the DNS query |
| 1285 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1286 | DatagramPacket packet = new DatagramPacket(buf, |
| 1287 | buf.length, dnsAddress, DNS_PORT); |
| 1288 | socket.send(packet); |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1289 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1290 | // Wait for reply (blocks for the above timeout) |
| 1291 | DatagramPacket replyPacket = new DatagramPacket(buf, buf.length); |
| 1292 | socket.receive(replyPacket); |
| 1293 | |
| 1294 | // If a timeout occurred, an exception would have been thrown. We got a reply! |
| 1295 | return true; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1296 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1297 | } catch (SocketException e) { |
| 1298 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 1299 | Slog.v(TAG, "DnsPinger.isReachable received SocketException", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1300 | } |
| 1301 | return false; |
Robert Greenwalt | 8e9abc5 | 2011-02-16 10:37:50 -0800 | [diff] [blame] | 1302 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1303 | } catch (UnknownHostException e) { |
| 1304 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 1305 | Slog.v(TAG, "DnsPinger.isReachable is unable to resolve the DNS host", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1306 | } |
| 1307 | return false; |
| 1308 | |
| 1309 | } catch (SocketTimeoutException e) { |
| 1310 | return false; |
| 1311 | |
| 1312 | } catch (IOException e) { |
| 1313 | if (V) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 1314 | Slog.v(TAG, "DnsPinger.isReachable got an IOException", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1315 | } |
| 1316 | return false; |
| 1317 | |
| 1318 | } catch (Exception e) { |
Joe Onorato | 43a1765 | 2011-04-06 19:22:23 -0700 | [diff] [blame] | 1319 | if (V || false) { |
Joe Onorato | 8a9b220 | 2010-02-26 18:56:32 -0800 | [diff] [blame] | 1320 | Slog.d(TAG, "DnsPinger.isReachable got an unknown exception", e); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1321 | } |
| 1322 | return false; |
Nick Kralevich | 929b485 | 2010-06-09 14:27:43 -0700 | [diff] [blame] | 1323 | } finally { |
| 1324 | if (socket != null) { |
| 1325 | socket.close(); |
| 1326 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1327 | } |
| 1328 | } |
| 1329 | |
| 1330 | private static void fillQuery(byte[] buf) { |
| 1331 | |
| 1332 | /* |
| 1333 | * See RFC2929 (though the bit tables in there are misleading for |
| 1334 | * us. For example, the recursion desired bit is the 0th bit for us, |
| 1335 | * but looking there it would appear as the 7th bit of the byte |
| 1336 | */ |
| 1337 | |
| 1338 | // Make sure it's all zeroed out |
| 1339 | for (int i = 0; i < buf.length; i++) buf[i] = 0; |
| 1340 | |
| 1341 | // Form a query for www.android.com |
| 1342 | |
| 1343 | // [0-1] bytes are an ID, generate random ID for this query |
| 1344 | buf[0] = (byte) sRandom.nextInt(256); |
| 1345 | buf[1] = (byte) sRandom.nextInt(256); |
| 1346 | |
| 1347 | // [2-3] bytes are for flags. |
| 1348 | buf[2] = 1; // Recursion desired |
| 1349 | |
| 1350 | // [4-5] bytes are for the query count |
| 1351 | buf[5] = 1; // One query |
| 1352 | |
| 1353 | // [6-7] [8-9] [10-11] are all counts of other fields we don't use |
| 1354 | |
| 1355 | // [12-15] for www |
| 1356 | writeString(buf, 12, "www"); |
| 1357 | |
| 1358 | // [16-23] for android |
| 1359 | writeString(buf, 16, "android"); |
| 1360 | |
| 1361 | // [24-27] for com |
| 1362 | writeString(buf, 24, "com"); |
| 1363 | |
| 1364 | // [29-30] bytes are for QTYPE, set to 1 |
| 1365 | buf[30] = 1; |
| 1366 | |
| 1367 | // [31-32] bytes are for QCLASS, set to 1 |
| 1368 | buf[32] = 1; |
| 1369 | } |
| 1370 | |
| 1371 | private static void writeString(byte[] buf, int startPos, String string) { |
| 1372 | int pos = startPos; |
| 1373 | |
| 1374 | // Write the length first |
| 1375 | buf[pos++] = (byte) string.length(); |
| 1376 | for (int i = 0; i < string.length(); i++) { |
| 1377 | buf[pos++] = (byte) string.charAt(i); |
| 1378 | } |
| 1379 | } |
| 1380 | } |
| 1381 | } |