1 /*
2  * Copyright (C) 2013 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.app.Notification;
20 import android.app.NotificationManager;
21 import android.app.TaskStackBuilder;
22 import android.content.BroadcastReceiver;
23 import android.content.Context;
24 import android.content.Intent;
25 import android.content.IntentFilter;
26 import android.database.ContentObserver;
27 import android.net.NetworkInfo;
28 import android.net.wifi.ScanResult;
29 import android.net.wifi.WifiManager;
30 import android.net.wifi.WifiScanner;
31 import android.os.Handler;
32 import android.os.Looper;
33 import android.os.Message;
34 import android.os.UserHandle;
35 import android.os.UserManager;
36 import android.provider.Settings;
37 
38 import com.android.internal.notification.SystemNotificationChannels;
39 
40 import java.io.FileDescriptor;
41 import java.io.PrintWriter;
42 import java.util.List;
43 
44 /**
45  * Takes care of handling the "open wi-fi network available" notification
46  * @hide
47  */
48 public class WifiNotificationController {
49     /**
50      * The icon to show in the 'available networks' notification. This will also
51      * be the ID of the Notification given to the NotificationManager.
52      */
53     private static final int ICON_NETWORKS_AVAILABLE =
54             com.android.internal.R.drawable.stat_notify_wifi_in_range;
55     /**
56      * When a notification is shown, we wait this amount before possibly showing it again.
57      */
58     private final long NOTIFICATION_REPEAT_DELAY_MS;
59 
60     /**
61      * Whether the user has set the setting to show the 'available networks' notification.
62      */
63     private boolean mNotificationEnabled;
64     /**
65      * Observes the user setting to keep {@link #mNotificationEnabled} in sync.
66      */
67     private NotificationEnabledSettingObserver mNotificationEnabledSettingObserver;
68 
69     /**
70      * The {@link System#currentTimeMillis()} must be at least this value for us
71      * to show the notification again.
72      */
73     private long mNotificationRepeatTime;
74     /**
75      * The Notification object given to the NotificationManager.
76      */
77     private Notification.Builder mNotificationBuilder;
78     /**
79      * Whether the notification is being shown, as set by us. That is, if the
80      * user cancels the notification, we will not receive the callback so this
81      * will still be true. We only guarantee if this is false, then the
82      * notification is not showing.
83      */
84     private boolean mNotificationShown;
85     /**
86      * The number of continuous scans that must occur before consider the
87      * supplicant in a scanning state. This allows supplicant to associate with
88      * remembered networks that are in the scan results.
89      */
90     private static final int NUM_SCANS_BEFORE_ACTUALLY_SCANNING = 3;
91     /**
92      * The number of scans since the last network state change. When this
93      * exceeds {@link #NUM_SCANS_BEFORE_ACTUALLY_SCANNING}, we consider the
94      * supplicant to actually be scanning. When the network state changes to
95      * something other than scanning, we reset this to 0.
96      */
97     private int mNumScansSinceNetworkStateChange;
98 
99     private final Context mContext;
100     private NetworkInfo mNetworkInfo;
101     private NetworkInfo.DetailedState mDetailedState;
102     private volatile int mWifiState;
103     private FrameworkFacade mFrameworkFacade;
104     private WifiInjector mWifiInjector;
105     private WifiScanner mWifiScanner;
106 
WifiNotificationController(Context context, Looper looper, FrameworkFacade framework, Notification.Builder builder, WifiInjector wifiInjector)107     WifiNotificationController(Context context,
108                                Looper looper,
109                                FrameworkFacade framework,
110                                Notification.Builder builder,
111                                WifiInjector wifiInjector) {
112         mContext = context;
113         mFrameworkFacade = framework;
114         mNotificationBuilder = builder;
115         mWifiInjector = wifiInjector;
116         mWifiState = WifiManager.WIFI_STATE_UNKNOWN;
117         mDetailedState = NetworkInfo.DetailedState.IDLE;
118 
119         IntentFilter filter = new IntentFilter();
120         filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
121         filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
122         filter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
123 
124         mContext.registerReceiver(
125                 new BroadcastReceiver() {
126                     @Override
127                     public void onReceive(Context context, Intent intent) {
128                         if (intent.getAction()
129                                 .equals(WifiManager.WIFI_STATE_CHANGED_ACTION)) {
130                             mWifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
131                                     WifiManager.WIFI_STATE_UNKNOWN);
132                             resetNotification();
133                         } else if (intent.getAction().equals(
134                                 WifiManager.NETWORK_STATE_CHANGED_ACTION)) {
135                             mNetworkInfo = (NetworkInfo) intent.getParcelableExtra(
136                                     WifiManager.EXTRA_NETWORK_INFO);
137                             NetworkInfo.DetailedState detailedState =
138                                     mNetworkInfo.getDetailedState();
139                             if (detailedState != NetworkInfo.DetailedState.SCANNING
140                                     && detailedState != mDetailedState) {
141                                 mDetailedState = detailedState;
142                                 // reset & clear notification on a network connect & disconnect
143                                 switch(mDetailedState) {
144                                     case CONNECTED:
145                                     case DISCONNECTED:
146                                     case CAPTIVE_PORTAL_CHECK:
147                                         resetNotification();
148                                         break;
149 
150                                     case IDLE:
151                                     case SCANNING:
152                                     case CONNECTING:
153                                     case AUTHENTICATING:
154                                     case OBTAINING_IPADDR:
155                                     case SUSPENDED:
156                                     case FAILED:
157                                     case BLOCKED:
158                                     case VERIFYING_POOR_LINK:
159                                         break;
160                                 }
161                             }
162                         } else if (intent.getAction().equals(
163                                 WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
164                             if (mWifiScanner == null) {
165                                 mWifiScanner = mWifiInjector.getWifiScanner();
166                             }
167                             checkAndSetNotification(mNetworkInfo,
168                                     mWifiScanner.getSingleScanResults());
169                         }
170                     }
171                 }, filter);
172 
173         // Setting is in seconds
174         NOTIFICATION_REPEAT_DELAY_MS = mFrameworkFacade.getIntegerSetting(context,
175                 Settings.Global.WIFI_NETWORKS_AVAILABLE_REPEAT_DELAY, 900) * 1000L;
176         mNotificationEnabledSettingObserver = new NotificationEnabledSettingObserver(
177                 new Handler(looper));
178         mNotificationEnabledSettingObserver.register();
179     }
180 
checkAndSetNotification(NetworkInfo networkInfo, List<ScanResult> scanResults)181     private synchronized void checkAndSetNotification(NetworkInfo networkInfo,
182             List<ScanResult> scanResults) {
183 
184         // TODO: unregister broadcast so we do not have to check here
185         // If we shouldn't place a notification on available networks, then
186         // don't bother doing any of the following
187         if (!mNotificationEnabled) return;
188         if (mWifiState != WifiManager.WIFI_STATE_ENABLED) return;
189         if (UserManager.get(mContext)
190                 .hasUserRestriction(UserManager.DISALLOW_CONFIG_WIFI, UserHandle.CURRENT)) {
191             return;
192         }
193 
194         NetworkInfo.State state = NetworkInfo.State.DISCONNECTED;
195         if (networkInfo != null)
196             state = networkInfo.getState();
197 
198         if ((state == NetworkInfo.State.DISCONNECTED)
199                 || (state == NetworkInfo.State.UNKNOWN)) {
200             if (scanResults != null) {
201                 int numOpenNetworks = 0;
202                 for (int i = scanResults.size() - 1; i >= 0; i--) {
203                     ScanResult scanResult = scanResults.get(i);
204 
205                     //A capability of [ESS] represents an open access point
206                     //that is available for an STA to connect
207                     if (scanResult.capabilities != null &&
208                             scanResult.capabilities.equals("[ESS]")) {
209                         numOpenNetworks++;
210                     }
211                 }
212 
213                 if (numOpenNetworks > 0) {
214                     if (++mNumScansSinceNetworkStateChange >= NUM_SCANS_BEFORE_ACTUALLY_SCANNING) {
215                         /*
216                          * We've scanned continuously at least
217                          * NUM_SCANS_BEFORE_NOTIFICATION times. The user
218                          * probably does not have a remembered network in range,
219                          * since otherwise supplicant would have tried to
220                          * associate and thus resetting this counter.
221                          */
222                         setNotificationVisible(true, numOpenNetworks, false, 0);
223                     }
224                     return;
225                 }
226             }
227         }
228 
229         // No open networks in range, remove the notification
230         setNotificationVisible(false, 0, false, 0);
231     }
232 
233     /**
234      * Clears variables related to tracking whether a notification has been
235      * shown recently and clears the current notification.
236      */
resetNotification()237     private synchronized void resetNotification() {
238         mNotificationRepeatTime = 0;
239         mNumScansSinceNetworkStateChange = 0;
240         setNotificationVisible(false, 0, false, 0);
241     }
242 
243     /**
244      * Display or don't display a notification that there are open Wi-Fi networks.
245      * @param visible {@code true} if notification should be visible, {@code false} otherwise
246      * @param numNetworks the number networks seen
247      * @param force {@code true} to force notification to be shown/not-shown,
248      * even if it is already shown/not-shown.
249      * @param delay time in milliseconds after which the notification should be made
250      * visible or invisible.
251      */
setNotificationVisible(boolean visible, int numNetworks, boolean force, int delay)252     private void setNotificationVisible(boolean visible, int numNetworks, boolean force,
253             int delay) {
254 
255         // Since we use auto cancel on the notification, when the
256         // mNetworksAvailableNotificationShown is true, the notification may
257         // have actually been canceled.  However, when it is false we know
258         // for sure that it is not being shown (it will not be shown any other
259         // place than here)
260 
261         // If it should be hidden and it is already hidden, then noop
262         if (!visible && !mNotificationShown && !force) {
263             return;
264         }
265 
266         NotificationManager notificationManager = (NotificationManager) mContext
267                 .getSystemService(Context.NOTIFICATION_SERVICE);
268 
269         Message message;
270         if (visible) {
271 
272             // Not enough time has passed to show the notification again
273             if (System.currentTimeMillis() < mNotificationRepeatTime) {
274                 return;
275             }
276 
277             if (mNotificationBuilder == null) {
278                 // Cache the Notification builder object.
279                 mNotificationBuilder = new Notification.Builder(mContext,
280                         SystemNotificationChannels.NETWORK_AVAILABLE)
281                         .setWhen(0)
282                         .setSmallIcon(ICON_NETWORKS_AVAILABLE)
283                         .setAutoCancel(true)
284                         .setContentIntent(TaskStackBuilder.create(mContext)
285                                 .addNextIntentWithParentStack(
286                                         new Intent(WifiManager.ACTION_PICK_WIFI_NETWORK))
287                                 .getPendingIntent(0, 0, null, UserHandle.CURRENT))
288                         .setColor(mContext.getResources().getColor(
289                                 com.android.internal.R.color.system_notification_accent_color));
290             }
291 
292             CharSequence title = mContext.getResources().getQuantityText(
293                     com.android.internal.R.plurals.wifi_available, numNetworks);
294             CharSequence details = mContext.getResources().getQuantityText(
295                     com.android.internal.R.plurals.wifi_available_detailed, numNetworks);
296             mNotificationBuilder.setTicker(title);
297             mNotificationBuilder.setContentTitle(title);
298             mNotificationBuilder.setContentText(details);
299 
300             mNotificationRepeatTime = System.currentTimeMillis() + NOTIFICATION_REPEAT_DELAY_MS;
301 
302             notificationManager.notifyAsUser(null, ICON_NETWORKS_AVAILABLE,
303                     mNotificationBuilder.build(), UserHandle.ALL);
304         } else {
305             notificationManager.cancelAsUser(null, ICON_NETWORKS_AVAILABLE, UserHandle.ALL);
306         }
307 
308         mNotificationShown = visible;
309     }
310 
dump(FileDescriptor fd, PrintWriter pw, String[] args)311     void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
312         pw.println("mNotificationEnabled " + mNotificationEnabled);
313         pw.println("mNotificationRepeatTime " + mNotificationRepeatTime);
314         pw.println("mNotificationShown " + mNotificationShown);
315         pw.println("mNumScansSinceNetworkStateChange " + mNumScansSinceNetworkStateChange);
316     }
317 
318     private class NotificationEnabledSettingObserver extends ContentObserver {
NotificationEnabledSettingObserver(Handler handler)319         public NotificationEnabledSettingObserver(Handler handler) {
320             super(handler);
321         }
322 
register()323         public void register() {
324             mFrameworkFacade.registerContentObserver(mContext, Settings.Global.getUriFor(
325                     Settings.Global.WIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON), true, this);
326             synchronized (WifiNotificationController.this) {
327                 mNotificationEnabled = getValue();
328             }
329         }
330 
331         @Override
onChange(boolean selfChange)332         public void onChange(boolean selfChange) {
333             super.onChange(selfChange);
334 
335             synchronized (WifiNotificationController.this) {
336                 mNotificationEnabled = getValue();
337                 resetNotification();
338             }
339         }
340 
getValue()341         private boolean getValue() {
342             return mFrameworkFacade.getIntegerSetting(mContext,
343                     Settings.Global.WIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON, 1) == 1;
344         }
345     }
346 }
347