1 /*
2  * Copyright (C) 2022 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.telephony.qns;
18 
19 import static com.android.telephony.qns.QnsConstants.INVALID_ID;
20 
21 import android.content.Context;
22 import android.net.ConnectivityManager;
23 import android.net.LinkProperties;
24 import android.net.Network;
25 import android.net.NetworkCapabilities;
26 import android.net.NetworkRequest;
27 import android.os.Handler;
28 import android.os.HandlerThread;
29 import android.os.Message;
30 import android.telephony.AccessNetworkConstants;
31 import android.util.Log;
32 
33 import com.android.internal.annotations.VisibleForTesting;
34 
35 import java.io.BufferedReader;
36 import java.io.IOException;
37 import java.io.InputStreamReader;
38 import java.net.Inet4Address;
39 import java.net.InetAddress;
40 import java.net.UnknownHostException;
41 import java.util.ArrayList;
42 import java.util.List;
43 
44 /**
45  * This class provides support for the RTT verification for Wifi. It schedules the RTT verification
46  * based on the UE state(Wifi connected, Cellular available, IMS registered on WLAN, operator
47  * support for RTT, etc).
48  */
49 class WifiBackhaulMonitor {
50     private static final int EVENT_START_RTT_CHECK = 1;
51     private static final int EVENT_IMS_REGISTRATION_STATE_CHANGED = 2;
52     private final String mTag;
53     private final ConnectivityManager mConnectivityManager;
54     private final QnsImsManager mQnsImsManager;
55     private final ConnectivityManager.NetworkCallback mNetworkCallback;
56     private final Context mContext;
57     private final int mSlotIndex;
58 
59     private final QnsRegistrantList mRegistrantList;
60     private final HandlerThread mHandlerThread;
61     private final Handler mHandler;
62     private final QnsCarrierConfigManager mConfigManager;
63     private final QnsTimer mQnsTimer;
64     private boolean mRttResult = false;
65 
66     ArrayList<InetAddress> mValidIpList = new ArrayList<>();
67     private boolean mIsCallbackRegistered = false;
68     private boolean mIsRttScheduled = false;
69     private boolean mIsCellularAvailable = false;
70     private boolean mIsIwlanConnected = false;
71     private boolean mIsRttRunning = false;
72     private String mInterfaceName = null;
73     private int mRttTimerId = INVALID_ID;
74 
75     private class BackhaulHandler extends Handler {
BackhaulHandler()76         BackhaulHandler() {
77             super(mHandlerThread.getLooper());
78         }
79 
80         @Override
handleMessage(Message msg)81         public void handleMessage(Message msg) {
82             super.handleMessage(msg);
83             log("handleMessage what = " + msg.what);
84             QnsAsyncResult ar;
85             switch (msg.what) {
86                 case EVENT_START_RTT_CHECK:
87                     onRttCheckStarted();
88                     break;
89                 case EVENT_IMS_REGISTRATION_STATE_CHANGED:
90                     ar = (QnsAsyncResult) msg.obj;
91                     onImsRegistrationStateChanged((QnsImsManager.ImsRegistrationState) ar.mResult);
92                     break;
93                 default:
94                     log("Invalid event = " + msg.what);
95             }
96         }
97     }
98 
99     private class WiFiStatusCallback extends ConnectivityManager.NetworkCallback {
100 
101         @Override
onAvailable(Network network)102         public void onAvailable(Network network) {
103             super.onAvailable(network);
104             if (network != null) {
105                 LinkProperties lp = mConnectivityManager.getLinkProperties(network);
106                 if (lp != null && lp.getInterfaceName().contains("wlan")) {
107                     mInterfaceName = lp.getInterfaceName();
108                 }
109             }
110         }
111 
112         @Override
onLost(Network network)113         public void onLost(Network network) {
114             super.onLost(network);
115             stopRttSchedule();
116             mInterfaceName = null;
117             mRttResult = false;
118         }
119     }
120     /**
121      * Constructor to create WifiBackhaulMonitor instance.
122      */
WifiBackhaulMonitor( Context context, QnsCarrierConfigManager configManager, QnsImsManager imsManager, QnsTimer qnstimer, int slotIndex)123     WifiBackhaulMonitor(
124             Context context,
125             QnsCarrierConfigManager configManager,
126             QnsImsManager imsManager,
127             QnsTimer qnstimer,
128             int slotIndex) {
129         mSlotIndex = slotIndex;
130         mTag = WifiBackhaulMonitor.class.getSimpleName() + "[" + mSlotIndex + "]";
131         mContext = context;
132         mConnectivityManager = mContext.getSystemService(ConnectivityManager.class);
133         mConfigManager = configManager;
134         mQnsImsManager = imsManager;
135         mQnsTimer = qnstimer;
136         mNetworkCallback = new WiFiStatusCallback();
137         mRegistrantList = new QnsRegistrantList();
138         mHandlerThread = new HandlerThread(mTag);
139         mHandlerThread.start();
140         mHandler = new BackhaulHandler();
141     }
142 
143     /** This method returns true if operator supports RTT feature. */
isRttCheckEnabled()144     boolean isRttCheckEnabled() {
145         return mConfigManager.getWlanRttServerAddressConfig() != null;
146     }
147 
148     /**
149      * Registers to receive the change in Round-trip-time(RTT) ICMP pings for Wifi.
150      *
151      * @param h {@link Handler} to handle the result of the RTT pings.
152      * @param what event which will be notified in handler.
153      */
registerForRttStatusChange(Handler h, int what)154     void registerForRttStatusChange(Handler h, int what) {
155         mRegistrantList.addUnique(h, what, null);
156         if (!mIsCallbackRegistered) {
157             mQnsImsManager.registerImsRegistrationStatusChanged(
158                     mHandler, EVENT_IMS_REGISTRATION_STATE_CHANGED);
159             mConnectivityManager.registerNetworkCallback(
160                     new NetworkRequest.Builder()
161                             .clearCapabilities()
162                             .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
163                             .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
164                             .build(),
165                     mNetworkCallback);
166             mIsCallbackRegistered = true;
167         }
168     }
169 
170     /**
171      * Unregisters the handler for RTT ICMP pings.
172      *
173      * @param h {@link Handler} to unregister the event
174      */
unRegisterForRttStatusChange(Handler h)175     void unRegisterForRttStatusChange(Handler h) {
176         mRegistrantList.remove(h);
177         if (mRegistrantList.size() == 0) {
178             clearAll();
179         }
180     }
181 
182     /** Triggers the request to check RTT. */
requestRttCheck()183     void requestRttCheck() {
184         if (!mIsRttRunning) {
185             if (mRttTimerId != INVALID_ID) {
186                 mQnsTimer.unregisterTimer(mRttTimerId);
187                 mRttTimerId = INVALID_ID;
188             }
189             mHandler.sendEmptyMessage(EVENT_START_RTT_CHECK);
190         } else {
191             log("RTT check is already running");
192         }
193     }
194 
195     /** Updates cellular availability in WifiBackhaulMonitor. */
setCellularAvailable(boolean cellularAvailable)196     void setCellularAvailable(boolean cellularAvailable) {
197         if (mIsCellularAvailable != cellularAvailable) {
198             mIsCellularAvailable = cellularAvailable;
199             if (mIsCellularAvailable) {
200                 startRttSchedule();
201             } else {
202                 stopRttSchedule();
203             }
204         }
205     }
206 
onRttCheckStarted()207     private void onRttCheckStarted() {
208         mIsRttRunning = true;
209         mRttResult = startRttCheck();
210         if (mIsRttScheduled && mRttResult) {
211             mIsRttScheduled = false;
212             startRttSchedule();
213         }
214         mIsRttRunning = false;
215         notifyRttResult();
216     }
217 
onImsRegistrationStateChanged(QnsImsManager.ImsRegistrationState info)218     private void onImsRegistrationStateChanged(QnsImsManager.ImsRegistrationState info) {
219         if (info.getTransportType() == AccessNetworkConstants.TRANSPORT_TYPE_WLAN) {
220             if (info.getEvent() == QnsConstants.IMS_REGISTRATION_CHANGED_REGISTERED) {
221                 mIsIwlanConnected = true;
222                 startRttSchedule();
223             } else if (info.getEvent() == QnsConstants.IMS_REGISTRATION_CHANGED_UNREGISTERED) {
224                 mIsIwlanConnected = false;
225                 stopRttSchedule();
226             }
227         } else if (info.getTransportType() == AccessNetworkConstants.TRANSPORT_TYPE_WWAN
228                 && info.getEvent() == QnsConstants.IMS_REGISTRATION_CHANGED_REGISTERED) {
229             mIsIwlanConnected = false;
230             stopRttSchedule();
231         }
232     }
233 
startRttSchedule()234     private void startRttSchedule() {
235         if (!mIsRttScheduled && mIsCellularAvailable && mIsIwlanConnected) {
236             int delay = mConfigManager.getWlanRttOtherConfigs()[4];
237             if (delay > 0) {
238                 startRttSchedule(delay);
239             }
240         }
241     }
242 
startRttSchedule(int delay)243     private void startRttSchedule(int delay) {
244         log("start RTT schedule for " + delay);
245         mRttTimerId = mQnsTimer.registerTimer(Message.obtain(mHandler, EVENT_START_RTT_CHECK),
246                 delay);
247         mIsRttScheduled = true;
248     }
249 
stopRttSchedule()250     private void stopRttSchedule() {
251         if (mIsRttScheduled) {
252             log("stop RTT schedule");
253             mQnsTimer.unregisterTimer(mRttTimerId);
254             mRttTimerId = INVALID_ID;
255             mIsRttScheduled = false;
256         }
257     }
258 
notifyRttResult()259     private void notifyRttResult() {
260         mRegistrantList.notifyResult(mRttResult);
261         mValidIpList.clear();
262     }
263 
startRttCheck()264     private boolean startRttCheck() {
265         if (mInterfaceName == null) {
266             log("Wifi interface is not set for RTT check");
267             return false;
268         }
269         int[] config = mConfigManager.getWlanRttOtherConfigs();
270         if (config == null || config.length == 0) {
271             log("No configurations are set for RTT check");
272             return true;
273         }
274 
275         int pingCount = config[0];
276         int intervalTime = Math.max(config[1], 200);
277         int pingSize = config[2];
278         int requiredRttAverage = config[3];
279         String rttPingServer = mConfigManager.getWlanRttServerAddressConfig();
280 
281         List<String>[] hostAddresses;
282         try {
283             hostAddresses = getHostAddresses(rttPingServer);
284         } catch (UnknownHostException e) {
285             log("Host not found for " + rttPingServer);
286             return true;
287         }
288 
289         boolean rttResult = true;
290         Runtime runtime = Runtime.getRuntime();
291         int ver = 0;
292         String[] pings = new String[] {"ping", "ping6"}; // ping for IPv4 and IPv6
293         for (String ping : pings) {
294             List<String> addresses = hostAddresses[ver];
295             for (String address : addresses) {
296                 StringBuilder command = new StringBuilder(ping);
297                 command.append(" -I ").append(mInterfaceName);
298                 command.append(" -i ").append((float) intervalTime / 1000);
299                 command.append(" -s ").append(pingSize);
300                 command.append(" -c ").append(pingCount);
301                 command.append(" ").append(address);
302                 try {
303                     Process p = runtime.exec(command.toString());
304                     BufferedReader br =
305                             new BufferedReader(new InputStreamReader(p.getInputStream()));
306                     String s;
307                     while ((s = br.readLine()) != null) {
308                         if (s.contains("/avg/")) {
309                             int i = s.indexOf("/", s.indexOf("="));
310                             String time = s.substring(i + 1, s.indexOf("/", i + 2));
311                             float avgRtt = Float.parseFloat(time);
312                             rttResult = avgRtt <= requiredRttAverage;
313                             if (rttResult) {
314                                 log("RTT check is success.");
315                                 return true;
316                             }
317                         }
318                     }
319                 } catch (IOException | NumberFormatException e) {
320                     e.printStackTrace();
321                 }
322             }
323             ver++;
324         }
325 
326         log("RTT Result: " + rttResult);
327         return rttResult;
328     }
329 
getHostAddresses(String rttPingServer)330     private List<String>[] getHostAddresses(String rttPingServer) throws UnknownHostException {
331         List<String>[] lists = new List[2];
332         lists[0] = new ArrayList<>(); // for IPv4
333         lists[1] = new ArrayList<>(); // for IPv6
334         InetAddress[] inetAddress = InetAddress.getAllByName(rttPingServer);
335         for (InetAddress addr : inetAddress) {
336             if (addr instanceof Inet4Address) {
337                 lists[0].add(addr.getHostAddress());
338             } else {
339                 lists[1].add(addr.getHostAddress());
340             }
341         }
342         return lists;
343     }
344 
345     /** Closes the current instance. */
close()346     void close() {
347         mHandlerThread.quit();
348         clearAll();
349     }
350 
351     /** Method to clear all settings in WifiBackhaulMonitor */
clearAll()352     void clearAll() {
353         stopRttSchedule();
354         mRegistrantList.removeAll();
355         if (mIsCallbackRegistered) {
356             mConnectivityManager.unregisterNetworkCallback(mNetworkCallback);
357             mQnsImsManager.unregisterImsRegistrationStatusChanged(mHandler);
358             mIsCallbackRegistered = false;
359         }
360         mIsRttRunning = false;
361         mIsCellularAvailable = false;
362         mIsIwlanConnected = false;
363         mIsRttScheduled = false;
364     }
365 
366     @VisibleForTesting
getRttTimerId()367     int getRttTimerId() {
368         return mRttTimerId;
369     }
370 
log(String s)371     private void log(String s) {
372         Log.d(mTag, s);
373     }
374 }
375