1/*
2 * Copyright (C) 2014 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
17package android.net;
18
19import android.Manifest;
20import android.annotation.SdkConstant;
21import android.annotation.SdkConstant.SdkConstantType;
22import android.annotation.SystemApi;
23import android.content.Context;
24import android.content.Intent;
25import android.net.NetworkScorerAppManager.NetworkScorerAppData;
26import android.os.IBinder;
27import android.os.RemoteException;
28import android.os.ServiceManager;
29import android.os.UserHandle;
30
31/**
32 * Class that manages communication between network subsystems and a network scorer.
33 *
34 * <p>You can get an instance of this class by calling
35 * {@link android.content.Context#getSystemService(String)}:
36 *
37 * <pre>NetworkScoreManager manager =
38 *     (NetworkScoreManager) getSystemService(Context.NETWORK_SCORE_SERVICE)</pre>
39 *
40 * <p>A network scorer is any application which:
41 * <ul>
42 * <li>Declares the {@link android.Manifest.permission#SCORE_NETWORKS} permission.
43 * <li>Includes a receiver for {@link #ACTION_SCORE_NETWORKS} guarded by the
44 *     {@link android.Manifest.permission#BROADCAST_NETWORK_PRIVILEGED} permission which scores
45 *     networks and (eventually) calls {@link #updateScores} with the results. If this receiver
46 *     specifies an android:label attribute, this label will be used when referring to the
47 *     application throughout system settings; otherwise, the application label will be used.
48 * </ul>
49 *
50 * <p>The system keeps track of an active scorer application; at any time, only this application
51 * will receive {@link #ACTION_SCORE_NETWORKS} broadcasts and will be permitted to call
52 * {@link #updateScores}. Applications may determine the current active scorer with
53 * {@link #getActiveScorerPackage()} and request to change the active scorer by sending an
54 * {@link #ACTION_CHANGE_ACTIVE} broadcast with another scorer.
55 *
56 * @hide
57 */
58@SystemApi
59public class NetworkScoreManager {
60    /**
61     * Activity action: ask the user to change the active network scorer. This will show a dialog
62     * that asks the user whether they want to replace the current active scorer with the one
63     * specified in {@link #EXTRA_PACKAGE_NAME}. The activity will finish with RESULT_OK if the
64     * active scorer was changed or RESULT_CANCELED if it failed for any reason.
65     */
66    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
67    public static final String ACTION_CHANGE_ACTIVE = "android.net.scoring.CHANGE_ACTIVE";
68
69    /**
70     * Extra used with {@link #ACTION_CHANGE_ACTIVE} to specify the new scorer package. Set with
71     * {@link android.content.Intent#putExtra(String, String)}.
72     */
73    public static final String EXTRA_PACKAGE_NAME = "packageName";
74
75    /**
76     * Broadcast action: new network scores are being requested. This intent will only be delivered
77     * to the current active scorer app. That app is responsible for scoring the networks and
78     * calling {@link #updateScores} when complete. The networks to score are specified in
79     * {@link #EXTRA_NETWORKS_TO_SCORE}, and will generally consist of all networks which have been
80     * configured by the user as well as any open networks.
81     *
82     * <p class="note">This is a protected intent that can only be sent by the system.
83     */
84    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
85    public static final String ACTION_SCORE_NETWORKS = "android.net.scoring.SCORE_NETWORKS";
86
87    /**
88     * Extra used with {@link #ACTION_SCORE_NETWORKS} to specify the networks to be scored, as an
89     * array of {@link NetworkKey}s. Can be obtained with
90     * {@link android.content.Intent#getParcelableArrayExtra(String)}}.
91     */
92    public static final String EXTRA_NETWORKS_TO_SCORE = "networksToScore";
93
94    /**
95     * Activity action: launch a custom activity for configuring a scorer before enabling it.
96     * Scorer applications may choose to specify an activity for this action, in which case the
97     * framework will launch that activity which should return RESULT_OK if scoring was enabled.
98     *
99     * <p>If no activity is included in a scorer which implements this action, the system dialog for
100     * selecting a scorer will be shown instead.
101     */
102    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
103    public static final String ACTION_CUSTOM_ENABLE = "android.net.scoring.CUSTOM_ENABLE";
104
105    /**
106     * Broadcast action: the active scorer has been changed. Scorer apps may listen to this to
107     * perform initialization once selected as the active scorer, or clean up unneeded resources
108     * if another scorer has been selected. This is an explicit broadcast only sent to the
109     * previous scorer and new scorer. Note that it is unnecessary to clear existing scores as
110     * this is handled by the system.
111     *
112     * <p>The new scorer will be specified in {@link #EXTRA_NEW_SCORER}.
113     *
114     * <p class="note">This is a protected intent that can only be sent by the system.
115     */
116    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
117    public static final String ACTION_SCORER_CHANGED = "android.net.scoring.SCORER_CHANGED";
118
119    /**
120     * Extra used with {@link #ACTION_SCORER_CHANGED} to specify the newly selected scorer's package
121     * name. Will be null if scoring was disabled. Can be obtained with
122     * {@link android.content.Intent#getStringExtra(String)}.
123     */
124    public static final String EXTRA_NEW_SCORER = "newScorer";
125
126    private final Context mContext;
127    private final INetworkScoreService mService;
128
129    /** @hide */
130    public NetworkScoreManager(Context context) {
131        mContext = context;
132        IBinder iBinder = ServiceManager.getService(Context.NETWORK_SCORE_SERVICE);
133        mService = INetworkScoreService.Stub.asInterface(iBinder);
134    }
135
136    /**
137     * Obtain the package name of the current active network scorer.
138     *
139     * <p>At any time, only one scorer application will receive {@link #ACTION_SCORE_NETWORKS}
140     * broadcasts and be allowed to call {@link #updateScores}. Applications may use this method to
141     * determine the current scorer and offer the user the ability to select a different scorer via
142     * the {@link #ACTION_CHANGE_ACTIVE} intent.
143     * @return the full package name of the current active scorer, or null if there is no active
144     *         scorer.
145     */
146    public String getActiveScorerPackage() {
147        NetworkScorerAppData app = NetworkScorerAppManager.getActiveScorer(mContext);
148        if (app == null) {
149            return null;
150        }
151        return app.mPackageName;
152    }
153
154    /**
155     * Update network scores.
156     *
157     * <p>This may be called at any time to re-score active networks. Scores will generally be
158     * updated quickly, but if this method is called too frequently, the scores may be held and
159     * applied at a later time.
160     *
161     * @param networks the networks which have been scored by the scorer.
162     * @return whether the update was successful.
163     * @throws SecurityException if the caller is not the active scorer.
164     */
165    public boolean updateScores(ScoredNetwork[] networks) throws SecurityException {
166        try {
167            return mService.updateScores(networks);
168        } catch (RemoteException e) {
169            throw e.rethrowFromSystemServer();
170        }
171    }
172
173    /**
174     * Clear network scores.
175     *
176     * <p>Should be called when all scores need to be invalidated, i.e. because the scoring
177     * algorithm has changed and old scores can no longer be compared to future scores.
178     *
179     * <p>Note that scores will be cleared automatically when the active scorer changes, as scores
180     * from one scorer cannot be compared to those from another scorer.
181     *
182     * @return whether the clear was successful.
183     * @throws SecurityException if the caller is not the active scorer or privileged.
184     */
185    public boolean clearScores() throws SecurityException {
186        try {
187            return mService.clearScores();
188        } catch (RemoteException e) {
189            throw e.rethrowFromSystemServer();
190        }
191    }
192
193    /**
194     * Set the active scorer to a new package and clear existing scores.
195     *
196     * <p>Should never be called directly without obtaining user consent. This can be done by using
197     * the {@link #ACTION_CHANGE_ACTIVE} broadcast, or using a custom configuration activity.
198     *
199     * @return true if the operation succeeded, or false if the new package is not a valid scorer.
200     * @throws SecurityException if the caller does not hold the
201     *         {@link android.Manifest.permission#SCORE_NETWORKS} permission.
202     * @hide
203     */
204    @SystemApi
205    public boolean setActiveScorer(String packageName) throws SecurityException {
206        try {
207            return mService.setActiveScorer(packageName);
208        } catch (RemoteException e) {
209            throw e.rethrowFromSystemServer();
210        }
211    }
212
213    /**
214     * Turn off network scoring.
215     *
216     * <p>May only be called by the current scorer app, or the system.
217     *
218     * @throws SecurityException if the caller is neither the active scorer nor the system.
219     */
220    public void disableScoring() throws SecurityException {
221        try {
222            mService.disableScoring();
223        } catch (RemoteException e) {
224            throw e.rethrowFromSystemServer();
225        }
226    }
227
228    /**
229     * Request scoring for networks.
230     *
231     * <p>Note that this is just a helper method to assemble the broadcast, and will run in the
232     * calling process.
233     *
234     * @return true if the broadcast was sent, or false if there is no active scorer.
235     * @throws SecurityException if the caller does not hold the
236     *         {@link android.Manifest.permission#BROADCAST_NETWORK_PRIVILEGED} permission.
237     * @hide
238     */
239    public boolean requestScores(NetworkKey[] networks) throws SecurityException {
240        String activeScorer = getActiveScorerPackage();
241        if (activeScorer == null) {
242            return false;
243        }
244        Intent intent = new Intent(ACTION_SCORE_NETWORKS);
245        intent.setPackage(activeScorer);
246        intent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
247        intent.putExtra(EXTRA_NETWORKS_TO_SCORE, networks);
248        // A scorer should never become active if its package doesn't hold SCORE_NETWORKS, but
249        // ensure the package still holds it to be extra safe.
250        // TODO: http://b/23422763
251        mContext.sendBroadcastAsUser(intent, UserHandle.SYSTEM, Manifest.permission.SCORE_NETWORKS);
252        return true;
253    }
254
255    /**
256     * Register a network score cache.
257     *
258     * @param networkType the type of network this cache can handle. See {@link NetworkKey#type}.
259     * @param scoreCache implementation of {@link INetworkScoreCache} to store the scores.
260     * @throws SecurityException if the caller does not hold the
261     *         {@link android.Manifest.permission#BROADCAST_NETWORK_PRIVILEGED} permission.
262     * @throws IllegalArgumentException if a score cache is already registered for this type.
263     * @hide
264     */
265    public void registerNetworkScoreCache(int networkType, INetworkScoreCache scoreCache) {
266        try {
267            mService.registerNetworkScoreCache(networkType, scoreCache);
268        } catch (RemoteException e) {
269            throw e.rethrowFromSystemServer();
270        }
271    }
272}
273