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 
17 package com.android.server.connectivity;
18 
19 import android.app.AlarmManager;
20 import android.app.PendingIntent;
21 import android.content.BroadcastReceiver;
22 import android.content.ComponentName;
23 import android.content.Context;
24 import android.content.Intent;
25 import android.content.IntentFilter;
26 import android.net.ConnectivityManager;
27 import android.net.Network;
28 import android.net.NetworkCapabilities;
29 import android.net.NetworkInfo;
30 import android.net.NetworkRequest;
31 import android.net.ProxyInfo;
32 import android.net.TrafficStats;
33 import android.net.Uri;
34 import android.net.wifi.WifiInfo;
35 import android.net.wifi.WifiManager;
36 import android.os.Handler;
37 import android.os.Message;
38 import android.os.SystemClock;
39 import android.os.SystemProperties;
40 import android.os.UserHandle;
41 import android.provider.Settings;
42 import android.telephony.CellIdentityCdma;
43 import android.telephony.CellIdentityGsm;
44 import android.telephony.CellIdentityLte;
45 import android.telephony.CellIdentityWcdma;
46 import android.telephony.CellInfo;
47 import android.telephony.CellInfoCdma;
48 import android.telephony.CellInfoGsm;
49 import android.telephony.CellInfoLte;
50 import android.telephony.CellInfoWcdma;
51 import android.telephony.TelephonyManager;
52 import android.util.Log;
53 
54 import com.android.internal.util.Protocol;
55 import com.android.internal.util.State;
56 import com.android.internal.util.StateMachine;
57 import com.android.server.ConnectivityService;
58 import com.android.server.connectivity.NetworkAgentInfo;
59 
60 import java.io.IOException;
61 import java.net.HttpURLConnection;
62 import java.net.URL;
63 import java.util.List;
64 import java.util.Random;
65 
66 /**
67  * {@hide}
68  */
69 public class NetworkMonitor extends StateMachine {
70     private static final boolean DBG = true;
71     private static final String TAG = "NetworkMonitor";
72     private static final String DEFAULT_SERVER = "connectivitycheck.android.com";
73     private static final int SOCKET_TIMEOUT_MS = 10000;
74     public static final String ACTION_NETWORK_CONDITIONS_MEASURED =
75             "android.net.conn.NETWORK_CONDITIONS_MEASURED";
76     public static final String EXTRA_CONNECTIVITY_TYPE = "extra_connectivity_type";
77     public static final String EXTRA_NETWORK_TYPE = "extra_network_type";
78     public static final String EXTRA_RESPONSE_RECEIVED = "extra_response_received";
79     public static final String EXTRA_IS_CAPTIVE_PORTAL = "extra_is_captive_portal";
80     public static final String EXTRA_CELL_ID = "extra_cellid";
81     public static final String EXTRA_SSID = "extra_ssid";
82     public static final String EXTRA_BSSID = "extra_bssid";
83     /** real time since boot */
84     public static final String EXTRA_REQUEST_TIMESTAMP_MS = "extra_request_timestamp_ms";
85     public static final String EXTRA_RESPONSE_TIMESTAMP_MS = "extra_response_timestamp_ms";
86 
87     private static final String PERMISSION_ACCESS_NETWORK_CONDITIONS =
88             "android.permission.ACCESS_NETWORK_CONDITIONS";
89 
90     // Keep these in sync with CaptivePortalLoginActivity.java.
91     // Intent broadcast from CaptivePortalLogin indicating sign-in is complete.
92     // Extras:
93     //     EXTRA_TEXT       = netId
94     //     LOGGED_IN_RESULT = one of the CAPTIVE_PORTAL_APP_RETURN_* values below.
95     //     RESPONSE_TOKEN   = data fragment from launching Intent
96     private static final String ACTION_CAPTIVE_PORTAL_LOGGED_IN =
97             "android.net.netmon.captive_portal_logged_in";
98     private static final String LOGGED_IN_RESULT = "result";
99     private static final String RESPONSE_TOKEN = "response_token";
100 
101     // After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
102     // The network should be used as a default internet connection.  It was found to be:
103     // 1. a functioning network providing internet access, or
104     // 2. a captive portal and the user decided to use it as is.
105     public static final int NETWORK_TEST_RESULT_VALID = 0;
106     // After a network has been tested this result can be sent with EVENT_NETWORK_TESTED.
107     // The network should not be used as a default internet connection.  It was found to be:
108     // 1. a captive portal and the user is prompted to sign-in, or
109     // 2. a captive portal and the user did not want to use it, or
110     // 3. a broken network (e.g. DNS failed, connect failed, HTTP request failed).
111     public static final int NETWORK_TEST_RESULT_INVALID = 1;
112 
113     private static final int BASE = Protocol.BASE_NETWORK_MONITOR;
114 
115     /**
116      * Inform NetworkMonitor that their network is connected.
117      * Initiates Network Validation.
118      */
119     public static final int CMD_NETWORK_CONNECTED = BASE + 1;
120 
121     /**
122      * Inform ConnectivityService that the network has been tested.
123      * obj = NetworkAgentInfo
124      * arg1 = One of the NETWORK_TESTED_RESULT_* constants.
125      */
126     public static final int EVENT_NETWORK_TESTED = BASE + 2;
127 
128     /**
129      * Inform NetworkMonitor to linger a network.  The Monitor should
130      * start a timer and/or start watching for zero live connections while
131      * moving towards LINGER_COMPLETE.  After the Linger period expires
132      * (or other events mark the end of the linger state) the LINGER_COMPLETE
133      * event should be sent and the network will be shut down.  If a
134      * CMD_NETWORK_CONNECTED happens before the LINGER completes
135      * it indicates further desire to keep the network alive and so
136      * the LINGER is aborted.
137      */
138     public static final int CMD_NETWORK_LINGER = BASE + 3;
139 
140     /**
141      * Message to self indicating linger delay has expired.
142      * arg1 = Token to ignore old messages.
143      */
144     private static final int CMD_LINGER_EXPIRED = BASE + 4;
145 
146     /**
147      * Inform ConnectivityService that the network LINGER period has
148      * expired.
149      * obj = NetworkAgentInfo
150      */
151     public static final int EVENT_NETWORK_LINGER_COMPLETE = BASE + 5;
152 
153     /**
154      * Message to self indicating it's time to evaluate a network's connectivity.
155      * arg1 = Token to ignore old messages.
156      */
157     private static final int CMD_REEVALUATE = BASE + 6;
158 
159     /**
160      * Inform NetworkMonitor that the network has disconnected.
161      */
162     public static final int CMD_NETWORK_DISCONNECTED = BASE + 7;
163 
164     /**
165      * Force evaluation even if it has succeeded in the past.
166      * arg1 = UID responsible for requesting this reeval.  Will be billed for data.
167      * arg2 = Number of evaluation attempts to make. (If 0, make INITIAL_ATTEMPTS attempts.)
168      */
169     public static final int CMD_FORCE_REEVALUATION = BASE + 8;
170 
171     /**
172      * Message to self indicating captive portal app finished.
173      * arg1 = one of: CAPTIVE_PORTAL_APP_RETURN_APPEASED,
174      *                CAPTIVE_PORTAL_APP_RETURN_UNWANTED,
175      *                CAPTIVE_PORTAL_APP_RETURN_WANTED_AS_IS
176      */
177     private static final int CMD_CAPTIVE_PORTAL_APP_FINISHED = BASE + 9;
178 
179     /**
180      * Request ConnectivityService display provisioning notification.
181      * arg1    = Whether to make the notification visible.
182      * arg2    = NetID.
183      * obj     = Intent to be launched when notification selected by user, null if !arg1.
184      */
185     public static final int EVENT_PROVISIONING_NOTIFICATION = BASE + 10;
186 
187     /**
188      * Message to self indicating sign-in app bypassed captive portal.
189      */
190     private static final int EVENT_APP_BYPASSED_CAPTIVE_PORTAL = BASE + 11;
191 
192     /**
193      * Message to self indicating no sign-in app responded.
194      */
195     private static final int EVENT_NO_APP_RESPONSE = BASE + 12;
196 
197     /**
198      * Message to self indicating sign-in app indicates sign-in is not possible.
199      */
200     private static final int EVENT_APP_INDICATES_SIGN_IN_IMPOSSIBLE = BASE + 13;
201 
202     /**
203      * Return codes from captive portal sign-in app.
204      */
205     public static final int CAPTIVE_PORTAL_APP_RETURN_APPEASED = 0;
206     public static final int CAPTIVE_PORTAL_APP_RETURN_UNWANTED = 1;
207     public static final int CAPTIVE_PORTAL_APP_RETURN_WANTED_AS_IS = 2;
208 
209     private static final String LINGER_DELAY_PROPERTY = "persist.netmon.linger";
210     // Default to 30s linger time-out.
211     private static final int DEFAULT_LINGER_DELAY_MS = 30000;
212     private final int mLingerDelayMs;
213     private int mLingerToken = 0;
214 
215     // Negative values disable reevaluation.
216     private static final String REEVALUATE_DELAY_PROPERTY = "persist.netmon.reeval_delay";
217     // When connecting, attempt to validate 3 times, pausing 5s between them.
218     private static final int DEFAULT_REEVALUATE_DELAY_MS = 5000;
219     private static final int INITIAL_ATTEMPTS = 3;
220     // If a network is not validated, make one attempt every 10 mins to see if it starts working.
221     private static final int REEVALUATE_PAUSE_MS = 10*60*1000;
222     private static final int PERIODIC_ATTEMPTS = 1;
223     // When an application calls reportBadNetwork, only make one attempt.
224     private static final int REEVALUATE_ATTEMPTS = 1;
225     private final int mReevaluateDelayMs;
226     private int mReevaluateToken = 0;
227     private static final int INVALID_UID = -1;
228     private int mUidResponsibleForReeval = INVALID_UID;
229 
230     private final Context mContext;
231     private final Handler mConnectivityServiceHandler;
232     private final NetworkAgentInfo mNetworkAgentInfo;
233     private final TelephonyManager mTelephonyManager;
234     private final WifiManager mWifiManager;
235     private final AlarmManager mAlarmManager;
236     private final NetworkRequest mDefaultRequest;
237 
238     private String mServer;
239     private boolean mIsCaptivePortalCheckEnabled = false;
240 
241     // Set if the user explicitly selected "Do not use this network" in captive portal sign-in app.
242     private boolean mUserDoesNotWant = false;
243 
244     // How many times we should attempt validation. Only checked in EvaluatingState; must be set
245     // before entering EvaluatingState. Note that whatever code causes us to transition to
246     // EvaluatingState last decides how many attempts will be made, so if one codepath were to
247     // enter EvaluatingState with a specific number of attempts, and then another were to enter it
248     // with a different number of attempts, the second number would be used. This is not currently
249     // a problem because EvaluatingState is not reentrant.
250     private int mMaxAttempts;
251 
252     public boolean systemReady = false;
253 
254     private final State mDefaultState = new DefaultState();
255     private final State mOfflineState = new OfflineState();
256     private final State mValidatedState = new ValidatedState();
257     private final State mMaybeNotifyState = new MaybeNotifyState();
258     private final State mEvaluatingState = new EvaluatingState();
259     private final State mCaptivePortalState = new CaptivePortalState();
260     private final State mLingeringState = new LingeringState();
261 
262     private CaptivePortalLoggedInBroadcastReceiver mCaptivePortalLoggedInBroadcastReceiver = null;
263     private String mCaptivePortalLoggedInResponseToken = null;
264 
NetworkMonitor(Context context, Handler handler, NetworkAgentInfo networkAgentInfo, NetworkRequest defaultRequest)265     public NetworkMonitor(Context context, Handler handler, NetworkAgentInfo networkAgentInfo,
266             NetworkRequest defaultRequest) {
267         // Add suffix indicating which NetworkMonitor we're talking about.
268         super(TAG + networkAgentInfo.name());
269 
270         mContext = context;
271         mConnectivityServiceHandler = handler;
272         mNetworkAgentInfo = networkAgentInfo;
273         mTelephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
274         mWifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
275         mAlarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
276         mDefaultRequest = defaultRequest;
277 
278         addState(mDefaultState);
279         addState(mOfflineState, mDefaultState);
280         addState(mValidatedState, mDefaultState);
281         addState(mMaybeNotifyState, mDefaultState);
282             addState(mEvaluatingState, mMaybeNotifyState);
283             addState(mCaptivePortalState, mMaybeNotifyState);
284         addState(mLingeringState, mDefaultState);
285         setInitialState(mDefaultState);
286 
287         mServer = Settings.Global.getString(mContext.getContentResolver(),
288                 Settings.Global.CAPTIVE_PORTAL_SERVER);
289         if (mServer == null) mServer = DEFAULT_SERVER;
290 
291         mLingerDelayMs = SystemProperties.getInt(LINGER_DELAY_PROPERTY, DEFAULT_LINGER_DELAY_MS);
292         mReevaluateDelayMs = SystemProperties.getInt(REEVALUATE_DELAY_PROPERTY,
293                 DEFAULT_REEVALUATE_DELAY_MS);
294 
295         mIsCaptivePortalCheckEnabled = Settings.Global.getInt(mContext.getContentResolver(),
296                 Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED, 1) == 1;
297 
298         mCaptivePortalLoggedInResponseToken = String.valueOf(new Random().nextLong());
299 
300         start();
301     }
302 
303     @Override
log(String s)304     protected void log(String s) {
305         Log.d(TAG + "/" + mNetworkAgentInfo.name(), s);
306     }
307 
308     // DefaultState is the parent of all States.  It exists only to handle CMD_* messages but
309     // does not entail any real state (hence no enter() or exit() routines).
310     private class DefaultState extends State {
311         @Override
processMessage(Message message)312         public boolean processMessage(Message message) {
313             if (DBG) log(getName() + message.toString());
314             switch (message.what) {
315                 case CMD_NETWORK_LINGER:
316                     if (DBG) log("Lingering");
317                     transitionTo(mLingeringState);
318                     return HANDLED;
319                 case CMD_NETWORK_CONNECTED:
320                     if (DBG) log("Connected");
321                     mMaxAttempts = INITIAL_ATTEMPTS;
322                     transitionTo(mEvaluatingState);
323                     return HANDLED;
324                 case CMD_NETWORK_DISCONNECTED:
325                     if (DBG) log("Disconnected - quitting");
326                     if (mCaptivePortalLoggedInBroadcastReceiver != null) {
327                         mContext.unregisterReceiver(mCaptivePortalLoggedInBroadcastReceiver);
328                         mCaptivePortalLoggedInBroadcastReceiver = null;
329                     }
330                     quit();
331                     return HANDLED;
332                 case CMD_FORCE_REEVALUATION:
333                     if (DBG) log("Forcing reevaluation");
334                     mUidResponsibleForReeval = message.arg1;
335                     mMaxAttempts = message.arg2 != 0 ? message.arg2 : REEVALUATE_ATTEMPTS;
336                     transitionTo(mEvaluatingState);
337                     return HANDLED;
338                 case CMD_CAPTIVE_PORTAL_APP_FINISHED:
339                     // Previous token was broadcast, come up with a new one.
340                     mCaptivePortalLoggedInResponseToken = String.valueOf(new Random().nextLong());
341                     switch (message.arg1) {
342                         case CAPTIVE_PORTAL_APP_RETURN_APPEASED:
343                         case CAPTIVE_PORTAL_APP_RETURN_WANTED_AS_IS:
344                             transitionTo(mValidatedState);
345                             break;
346                         case CAPTIVE_PORTAL_APP_RETURN_UNWANTED:
347                             mUserDoesNotWant = true;
348                             // TODO: Should teardown network.
349                             transitionTo(mOfflineState);
350                             break;
351                     }
352                     return HANDLED;
353                 default:
354                     return HANDLED;
355             }
356         }
357     }
358 
359     // Being in the OfflineState State indicates a Network is unwanted or failed validation.
360     private class OfflineState extends State {
361         @Override
enter()362         public void enter() {
363             mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
364                     NETWORK_TEST_RESULT_INVALID, 0, mNetworkAgentInfo));
365             if (!mUserDoesNotWant) {
366                 sendMessageDelayed(CMD_FORCE_REEVALUATION, 0 /* no UID */,
367                         PERIODIC_ATTEMPTS, REEVALUATE_PAUSE_MS);
368             }
369         }
370 
371         @Override
processMessage(Message message)372         public boolean processMessage(Message message) {
373             if (DBG) log(getName() + message.toString());
374                         switch (message.what) {
375                 case CMD_FORCE_REEVALUATION:
376                     // If the user has indicated they explicitly do not want to use this network,
377                     // don't allow a reevaluation as this will be pointless and could result in
378                     // the user being annoyed with repeated unwanted notifications.
379                     return mUserDoesNotWant ? HANDLED : NOT_HANDLED;
380                 default:
381                     return NOT_HANDLED;
382             }
383         }
384 
385         @Override
exit()386         public void exit() {
387              // NOTE: This removes the delayed message posted by enter() but will inadvertently
388              // remove any other CMD_FORCE_REEVALUATION in the message queue.  At the moment this
389              // is harmless.  If in the future this becomes problematic a different message could
390              // be used.
391              removeMessages(CMD_FORCE_REEVALUATION);
392         }
393     }
394 
395     // Being in the ValidatedState State indicates a Network is:
396     // - Successfully validated, or
397     // - Wanted "as is" by the user, or
398     // - Does not satsify the default NetworkRequest and so validation has been skipped.
399     private class ValidatedState extends State {
400         @Override
enter()401         public void enter() {
402             if (DBG) log("Validated");
403             mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
404                     NETWORK_TEST_RESULT_VALID, 0, mNetworkAgentInfo));
405         }
406 
407         @Override
processMessage(Message message)408         public boolean processMessage(Message message) {
409             if (DBG) log(getName() + message.toString());
410             switch (message.what) {
411                 case CMD_NETWORK_CONNECTED:
412                     transitionTo(mValidatedState);
413                     return HANDLED;
414                 default:
415                     return NOT_HANDLED;
416             }
417         }
418     }
419 
420     // Being in the MaybeNotifyState State indicates the user may have been notified that sign-in
421     // is required.  This State takes care to clear the notification upon exit from the State.
422     private class MaybeNotifyState extends State {
423         @Override
exit()424         public void exit() {
425             Message message = obtainMessage(EVENT_PROVISIONING_NOTIFICATION, 0,
426                     mNetworkAgentInfo.network.netId, null);
427             mConnectivityServiceHandler.sendMessage(message);
428         }
429     }
430 
431     // Being in the EvaluatingState State indicates the Network is being evaluated for internet
432     // connectivity.
433     private class EvaluatingState extends State {
434         private int mAttempt;
435 
436         @Override
enter()437         public void enter() {
438             mAttempt = 1;
439             sendMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
440             if (mUidResponsibleForReeval != INVALID_UID) {
441                 TrafficStats.setThreadStatsUid(mUidResponsibleForReeval);
442                 mUidResponsibleForReeval = INVALID_UID;
443             }
444         }
445 
446         @Override
processMessage(Message message)447         public boolean processMessage(Message message) {
448             if (DBG) log(getName() + message.toString());
449             switch (message.what) {
450                 case CMD_REEVALUATE:
451                     if (message.arg1 != mReevaluateToken)
452                         return HANDLED;
453                     // Don't bother validating networks that don't satisify the default request.
454                     // This includes:
455                     //  - VPNs which can be considered explicitly desired by the user and the
456                     //    user's desire trumps whether the network validates.
457                     //  - Networks that don't provide internet access.  It's unclear how to
458                     //    validate such networks.
459                     //  - Untrusted networks.  It's unsafe to prompt the user to sign-in to
460                     //    such networks and the user didn't express interest in connecting to
461                     //    such networks (an app did) so the user may be unhappily surprised when
462                     //    asked to sign-in to a network they didn't want to connect to in the
463                     //    first place.  Validation could be done to adjust the network scores
464                     //    however these networks are app-requested and may not be intended for
465                     //    general usage, in which case general validation may not be an accurate
466                     //    measure of the network's quality.  Only the app knows how to evaluate
467                     //    the network so don't bother validating here.  Furthermore sending HTTP
468                     //    packets over the network may be undesirable, for example an extremely
469                     //    expensive metered network, or unwanted leaking of the User Agent string.
470                     if (!mDefaultRequest.networkCapabilities.satisfiedByNetworkCapabilities(
471                             mNetworkAgentInfo.networkCapabilities)) {
472                         transitionTo(mValidatedState);
473                         return HANDLED;
474                     }
475                     // Note: This call to isCaptivePortal() could take up to a minute. Resolving the
476                     // server's IP addresses could hit the DNS timeout, and attempting connections
477                     // to each of the server's several IP addresses (currently one IPv4 and one
478                     // IPv6) could each take SOCKET_TIMEOUT_MS.  During this time this StateMachine
479                     // will be unresponsive. isCaptivePortal() could be executed on another Thread
480                     // if this is found to cause problems.
481                     int httpResponseCode = isCaptivePortal();
482                     if (httpResponseCode == 204) {
483                         transitionTo(mValidatedState);
484                     } else if (httpResponseCode >= 200 && httpResponseCode <= 399) {
485                         transitionTo(mCaptivePortalState);
486                     } else if (++mAttempt > mMaxAttempts) {
487                         transitionTo(mOfflineState);
488                     } else if (mReevaluateDelayMs >= 0) {
489                         Message msg = obtainMessage(CMD_REEVALUATE, ++mReevaluateToken, 0);
490                         sendMessageDelayed(msg, mReevaluateDelayMs);
491                     }
492                     return HANDLED;
493                 case CMD_FORCE_REEVALUATION:
494                     // Ignore duplicate requests.
495                     return HANDLED;
496                 default:
497                     return NOT_HANDLED;
498             }
499         }
500 
501         @Override
exit()502         public void exit() {
503             TrafficStats.clearThreadStatsUid();
504         }
505     }
506 
507     // BroadcastReceiver that waits for a particular Intent and then posts a message.
508     private class CustomIntentReceiver extends BroadcastReceiver {
509         private final int mToken;
510         private final int mWhat;
511         private final String mAction;
CustomIntentReceiver(String action, int token, int what)512         CustomIntentReceiver(String action, int token, int what) {
513             mToken = token;
514             mWhat = what;
515             mAction = action + "_" + mNetworkAgentInfo.network.netId + "_" + token;
516             mContext.registerReceiver(this, new IntentFilter(mAction));
517         }
getPendingIntent()518         public PendingIntent getPendingIntent() {
519             return PendingIntent.getBroadcast(mContext, 0, new Intent(mAction), 0);
520         }
521         @Override
onReceive(Context context, Intent intent)522         public void onReceive(Context context, Intent intent) {
523             if (intent.getAction().equals(mAction)) sendMessage(obtainMessage(mWhat, mToken));
524         }
525     }
526 
527     private class CaptivePortalLoggedInBroadcastReceiver extends BroadcastReceiver {
528         @Override
onReceive(Context context, Intent intent)529         public void onReceive(Context context, Intent intent) {
530             if (Integer.parseInt(intent.getStringExtra(Intent.EXTRA_TEXT)) ==
531                     mNetworkAgentInfo.network.netId &&
532                     mCaptivePortalLoggedInResponseToken.equals(
533                             intent.getStringExtra(RESPONSE_TOKEN))) {
534                 sendMessage(obtainMessage(CMD_CAPTIVE_PORTAL_APP_FINISHED,
535                         Integer.parseInt(intent.getStringExtra(LOGGED_IN_RESULT)), 0));
536             }
537         }
538     }
539 
540     // Being in the CaptivePortalState State indicates a captive portal was detected and the user
541     // has been shown a notification to sign-in.
542     private class CaptivePortalState extends State {
543         @Override
enter()544         public void enter() {
545             mConnectivityServiceHandler.sendMessage(obtainMessage(EVENT_NETWORK_TESTED,
546                     NETWORK_TEST_RESULT_INVALID, 0, mNetworkAgentInfo));
547 
548             // Assemble Intent to launch captive portal sign-in app.
549             final Intent intent = new Intent(Intent.ACTION_SEND);
550             // Intent cannot use extras because PendingIntent.getActivity will merge matching
551             // Intents erasing extras.  Use data instead of extras to encode NetID.
552             intent.setData(Uri.fromParts("netid", Integer.toString(mNetworkAgentInfo.network.netId),
553                     mCaptivePortalLoggedInResponseToken));
554             intent.setComponent(new ComponentName("com.android.captiveportallogin",
555                     "com.android.captiveportallogin.CaptivePortalLoginActivity"));
556             intent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_NEW_TASK);
557 
558             if (mCaptivePortalLoggedInBroadcastReceiver == null) {
559                 // Wait for result.
560                 mCaptivePortalLoggedInBroadcastReceiver =
561                         new CaptivePortalLoggedInBroadcastReceiver();
562                 final IntentFilter filter = new IntentFilter(ACTION_CAPTIVE_PORTAL_LOGGED_IN);
563                 mContext.registerReceiver(mCaptivePortalLoggedInBroadcastReceiver, filter);
564             }
565             // Initiate notification to sign-in.
566             Message message = obtainMessage(EVENT_PROVISIONING_NOTIFICATION, 1,
567                     mNetworkAgentInfo.network.netId,
568                     PendingIntent.getActivity(mContext, 0, intent, 0));
569             mConnectivityServiceHandler.sendMessage(message);
570         }
571 
572         @Override
processMessage(Message message)573         public boolean processMessage(Message message) {
574             if (DBG) log(getName() + message.toString());
575             return NOT_HANDLED;
576         }
577     }
578 
579     // Being in the LingeringState State indicates a Network's validated bit is true and it once
580     // was the highest scoring Network satisfying a particular NetworkRequest, but since then
581     // another Network satsified the NetworkRequest with a higher score and hence this Network
582     // is "lingered" for a fixed period of time before it is disconnected.  This period of time
583     // allows apps to wrap up communication and allows for seamless reactivation if the other
584     // higher scoring Network happens to disconnect.
585     private class LingeringState extends State {
586         private static final String ACTION_LINGER_EXPIRED = "android.net.netmon.lingerExpired";
587 
588         private CustomIntentReceiver mBroadcastReceiver;
589         private PendingIntent mIntent;
590 
591         @Override
enter()592         public void enter() {
593             mLingerToken = new Random().nextInt();
594             mBroadcastReceiver = new CustomIntentReceiver(ACTION_LINGER_EXPIRED, mLingerToken,
595                     CMD_LINGER_EXPIRED);
596             mIntent = mBroadcastReceiver.getPendingIntent();
597             long wakeupTime = SystemClock.elapsedRealtime() + mLingerDelayMs;
598             mAlarmManager.setWindow(AlarmManager.ELAPSED_REALTIME_WAKEUP, wakeupTime,
599                     // Give a specific window so we aren't subject to unknown inexactitude.
600                     mLingerDelayMs / 6, mIntent);
601         }
602 
603         @Override
processMessage(Message message)604         public boolean processMessage(Message message) {
605             if (DBG) log(getName() + message.toString());
606             switch (message.what) {
607                 case CMD_NETWORK_CONNECTED:
608                     // Go straight to active as we've already evaluated.
609                     transitionTo(mValidatedState);
610                     return HANDLED;
611                 case CMD_LINGER_EXPIRED:
612                     if (message.arg1 != mLingerToken)
613                         return HANDLED;
614                     mConnectivityServiceHandler.sendMessage(
615                             obtainMessage(EVENT_NETWORK_LINGER_COMPLETE, mNetworkAgentInfo));
616                     return HANDLED;
617                 case CMD_FORCE_REEVALUATION:
618                     // Ignore reevaluation attempts when lingering.  A reevaluation could result
619                     // in a transition to the validated state which would abort the linger
620                     // timeout.  Lingering is the result of score assessment; validity is
621                     // irrelevant.
622                     return HANDLED;
623                 case CMD_CAPTIVE_PORTAL_APP_FINISHED:
624                     // Ignore user network determination as this could abort linger timeout.
625                     // Networks are only lingered once validated because:
626                     // - Unvalidated networks are never lingered (see rematchNetworkAndRequests).
627                     // - Once validated, a Network's validated bit is never cleared.
628                     // Since networks are only lingered after being validated a user's
629                     // determination will not change the death sentence that lingering entails:
630                     // - If the user wants to use the network or bypasses the captive portal,
631                     //   the network's score will not be increased beyond its current value
632                     //   because it is already validated.  Without a score increase there is no
633                     //   chance of reactivation (i.e. aborting linger timeout).
634                     // - If the user does not want the network, lingering will disconnect the
635                     //   network anyhow.
636                     return HANDLED;
637                 default:
638                     return NOT_HANDLED;
639             }
640         }
641 
642         @Override
exit()643         public void exit() {
644             mAlarmManager.cancel(mIntent);
645             mContext.unregisterReceiver(mBroadcastReceiver);
646         }
647     }
648 
649     /**
650      * Do a URL fetch on a known server to see if we get the data we expect.
651      * Returns HTTP response code.
652      */
isCaptivePortal()653     private int isCaptivePortal() {
654         if (!mIsCaptivePortalCheckEnabled) return 204;
655 
656         HttpURLConnection urlConnection = null;
657         int httpResponseCode = 599;
658         try {
659             URL url = new URL("http", mServer, "/generate_204");
660             // On networks with a PAC instead of fetching a URL that should result in a 204
661             // reponse, we instead simply fetch the PAC script.  This is done for a few reasons:
662             // 1. At present our PAC code does not yet handle multiple PACs on multiple networks
663             //    until something like https://android-review.googlesource.com/#/c/115180/ lands.
664             //    Network.openConnection() will ignore network-specific PACs and instead fetch
665             //    using NO_PROXY.  If a PAC is in place, the only fetch we know will succeed with
666             //    NO_PROXY is the fetch of the PAC itself.
667             // 2. To proxy the generate_204 fetch through a PAC would require a number of things
668             //    happen before the fetch can commence, namely:
669             //        a) the PAC script be fetched
670             //        b) a PAC script resolver service be fired up and resolve mServer
671             //    Network validation could be delayed until these prerequisities are satisifed or
672             //    could simply be left to race them.  Neither is an optimal solution.
673             // 3. PAC scripts are sometimes used to block or restrict Internet access and may in
674             //    fact block fetching of the generate_204 URL which would lead to false negative
675             //    results for network validation.
676             boolean fetchPac = false;
677             {
678                 final ProxyInfo proxyInfo = mNetworkAgentInfo.linkProperties.getHttpProxy();
679                 if (proxyInfo != null && !Uri.EMPTY.equals(proxyInfo.getPacFileUrl())) {
680                     url = new URL(proxyInfo.getPacFileUrl().toString());
681                     fetchPac = true;
682                 }
683             }
684             if (DBG) {
685                 log("Checking " + url.toString() + " on " +
686                         mNetworkAgentInfo.networkInfo.getExtraInfo());
687             }
688             urlConnection = (HttpURLConnection) mNetworkAgentInfo.network.openConnection(url);
689             urlConnection.setInstanceFollowRedirects(fetchPac);
690             urlConnection.setConnectTimeout(SOCKET_TIMEOUT_MS);
691             urlConnection.setReadTimeout(SOCKET_TIMEOUT_MS);
692             urlConnection.setUseCaches(false);
693 
694             // Time how long it takes to get a response to our request
695             long requestTimestamp = SystemClock.elapsedRealtime();
696 
697             urlConnection.getInputStream();
698 
699             // Time how long it takes to get a response to our request
700             long responseTimestamp = SystemClock.elapsedRealtime();
701 
702             httpResponseCode = urlConnection.getResponseCode();
703             if (DBG) {
704                 log("isCaptivePortal: ret=" + httpResponseCode +
705                         " headers=" + urlConnection.getHeaderFields());
706             }
707             // NOTE: We may want to consider an "HTTP/1.0 204" response to be a captive
708             // portal.  The only example of this seen so far was a captive portal.  For
709             // the time being go with prior behavior of assuming it's not a captive
710             // portal.  If it is considered a captive portal, a different sign-in URL
711             // is needed (i.e. can't browse a 204).  This could be the result of an HTTP
712             // proxy server.
713 
714             // Consider 200 response with "Content-length=0" to not be a captive portal.
715             // There's no point in considering this a captive portal as the user cannot
716             // sign-in to an empty page.  Probably the result of a broken transparent proxy.
717             // See http://b/9972012.
718             if (httpResponseCode == 200 && urlConnection.getContentLength() == 0) {
719                 if (DBG) log("Empty 200 response interpreted as 204 response.");
720                 httpResponseCode = 204;
721             }
722 
723             if (httpResponseCode == 200 && fetchPac) {
724                 if (DBG) log("PAC fetch 200 response interpreted as 204 response.");
725                 httpResponseCode = 204;
726             }
727 
728             sendNetworkConditionsBroadcast(true /* response received */,
729                     httpResponseCode != 204 /* isCaptivePortal */,
730                     requestTimestamp, responseTimestamp);
731         } catch (IOException e) {
732             if (DBG) log("Probably not a portal: exception " + e);
733             if (httpResponseCode == 599) {
734                 // TODO: Ping gateway and DNS server and log results.
735             }
736         } finally {
737             if (urlConnection != null) {
738                 urlConnection.disconnect();
739             }
740         }
741         return httpResponseCode;
742     }
743 
744     /**
745      * @param responseReceived - whether or not we received a valid HTTP response to our request.
746      * If false, isCaptivePortal and responseTimestampMs are ignored
747      * TODO: This should be moved to the transports.  The latency could be passed to the transports
748      * along with the captive portal result.  Currently the TYPE_MOBILE broadcasts appear unused so
749      * perhaps this could just be added to the WiFi transport only.
750      */
sendNetworkConditionsBroadcast(boolean responseReceived, boolean isCaptivePortal, long requestTimestampMs, long responseTimestampMs)751     private void sendNetworkConditionsBroadcast(boolean responseReceived, boolean isCaptivePortal,
752             long requestTimestampMs, long responseTimestampMs) {
753         if (Settings.Global.getInt(mContext.getContentResolver(),
754                 Settings.Global.WIFI_SCAN_ALWAYS_AVAILABLE, 0) == 0) {
755             if (DBG) log("Don't send network conditions - lacking user consent.");
756             return;
757         }
758 
759         if (systemReady == false) return;
760 
761         Intent latencyBroadcast = new Intent(ACTION_NETWORK_CONDITIONS_MEASURED);
762         switch (mNetworkAgentInfo.networkInfo.getType()) {
763             case ConnectivityManager.TYPE_WIFI:
764                 WifiInfo currentWifiInfo = mWifiManager.getConnectionInfo();
765                 if (currentWifiInfo != null) {
766                     // NOTE: getSSID()'s behavior changed in API 17; before that, SSIDs were not
767                     // surrounded by double quotation marks (thus violating the Javadoc), but this
768                     // was changed to match the Javadoc in API 17. Since clients may have started
769                     // sanitizing the output of this method since API 17 was released, we should
770                     // not change it here as it would become impossible to tell whether the SSID is
771                     // simply being surrounded by quotes due to the API, or whether those quotes
772                     // are actually part of the SSID.
773                     latencyBroadcast.putExtra(EXTRA_SSID, currentWifiInfo.getSSID());
774                     latencyBroadcast.putExtra(EXTRA_BSSID, currentWifiInfo.getBSSID());
775                 } else {
776                     if (DBG) logw("network info is TYPE_WIFI but no ConnectionInfo found");
777                     return;
778                 }
779                 break;
780             case ConnectivityManager.TYPE_MOBILE:
781                 latencyBroadcast.putExtra(EXTRA_NETWORK_TYPE, mTelephonyManager.getNetworkType());
782                 List<CellInfo> info = mTelephonyManager.getAllCellInfo();
783                 if (info == null) return;
784                 int numRegisteredCellInfo = 0;
785                 for (CellInfo cellInfo : info) {
786                     if (cellInfo.isRegistered()) {
787                         numRegisteredCellInfo++;
788                         if (numRegisteredCellInfo > 1) {
789                             if (DBG) log("more than one registered CellInfo.  Can't " +
790                                     "tell which is active.  Bailing.");
791                             return;
792                         }
793                         if (cellInfo instanceof CellInfoCdma) {
794                             CellIdentityCdma cellId = ((CellInfoCdma) cellInfo).getCellIdentity();
795                             latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
796                         } else if (cellInfo instanceof CellInfoGsm) {
797                             CellIdentityGsm cellId = ((CellInfoGsm) cellInfo).getCellIdentity();
798                             latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
799                         } else if (cellInfo instanceof CellInfoLte) {
800                             CellIdentityLte cellId = ((CellInfoLte) cellInfo).getCellIdentity();
801                             latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
802                         } else if (cellInfo instanceof CellInfoWcdma) {
803                             CellIdentityWcdma cellId = ((CellInfoWcdma) cellInfo).getCellIdentity();
804                             latencyBroadcast.putExtra(EXTRA_CELL_ID, cellId);
805                         } else {
806                             if (DBG) logw("Registered cellinfo is unrecognized");
807                             return;
808                         }
809                     }
810                 }
811                 break;
812             default:
813                 return;
814         }
815         latencyBroadcast.putExtra(EXTRA_CONNECTIVITY_TYPE, mNetworkAgentInfo.networkInfo.getType());
816         latencyBroadcast.putExtra(EXTRA_RESPONSE_RECEIVED, responseReceived);
817         latencyBroadcast.putExtra(EXTRA_REQUEST_TIMESTAMP_MS, requestTimestampMs);
818 
819         if (responseReceived) {
820             latencyBroadcast.putExtra(EXTRA_IS_CAPTIVE_PORTAL, isCaptivePortal);
821             latencyBroadcast.putExtra(EXTRA_RESPONSE_TIMESTAMP_MS, responseTimestampMs);
822         }
823         mContext.sendBroadcastAsUser(latencyBroadcast, UserHandle.CURRENT,
824                 PERMISSION_ACCESS_NETWORK_CONDITIONS);
825     }
826 }
827