【Android架构Telephony篇】数据业务(2)RILJ 【转】

转自 https://blog.csdn.net/u013686019/article/details/49719897
 

 

一、Telephony整体流程

Telephony执行的完整流程如下：

下面自上而下，只关注主干，分层看下代码走向。

 

 

二、Telephony数据业务的RILJ层

 

1、App层

用户点击系统【设置】进行开启/关闭数据业务，调用：

 

1. DataUsageSummary.java (packages\apps\settings\src\com\android\settings)

2. private void setMobileDataEnabled(int subId, boolean enabled) {

3. mTelephonyManager.setDataEnabled(subId, enabled);

4. }

TelephonyManager作为"phone"系统服务的管理类，其获取方式可以：

 

 

1. DataUsageSummary#onCreate()

2. -->mTelephonyManager = TelephonyManager.from(context);

3.  

4. TelephonyManager.java (frameworks\base\telephony\java\android\telephony)

5. public static TelephonyManager from(Context context) {

6. return (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);

7. }

 

 

在上图中，把"phone"系统服务获取放在了frameworks层，这是因为在frameworks中可以越过Manager类直接获取服务，如：

 

1. TelephonyManager.java (frameworks\base\telephony\java\android\telephony)

2. private ITelephony getITelephony() {

3. return ITelephony.Stub.asInterface(ServiceManager.getService(Context.TELEPHONY_SERVICE));

4. }

5.  

6. public void setDataEnabled(int subId, boolean enable) {

7. ITelephony telephony = getITelephony();

8. telephony.setDataEnabled(subId, enable);

9. }

Telephony提供的操作无线模组的方法可以通过ITelephony.aidl文件查看：

 

frameworks/base/telephony/java/com/android/internal/telephony/ITelephony.aidl

 

 

2、Framework层

(1)"phone"系统服务注册

系统服务绝大部分都在frameworks/base/services/java/com/android/server/SystemServer.java文件中统一注册，但TELEPHONY_SERVICE("phone")服务很是另类，其注册流程：

 

1. PhoneApp.java (packages\services\telephony\src\com\android\phone)

2. public class PhoneApp extends Application {}

3. PhoneApp#onCreate()

4. -->PhoneGlobals#onCreate()

5. ---->PhoneInterfaceManager#init()

6. ------>PhoneInterfaceManager#publish()

7. -------->PhoneInterfaceManager#ServiceManager.addService("phone", this);

 

adb shell进去系统，通过service命令可以查看系统注册的所有服务：

 

1. # service list

2. Found 102 services:

3. 1 phone: [com.android.internal.telephony.ITelephony]

(2) 继续数据业务流程

 

PhoneInterfaceManager是"phone"服务实现方，对于数据开启/关闭：

 

1. PhoneInterfaceManager.java (packages\services\telephony\src\com\android\phone)

2. /**

3. * Set mobile data enabled

4. * Used by the user through settings etc to turn on/off mobile data

5. */

6. @Override

7. public void setDataEnabled(int subId, boolean enable) {

8. enforceModifyPermission(); -->a

9. int phoneId = mSubscriptionController.getPhoneId(subId); -->b

10. Phone phone = PhoneFactory.getPhone(phoneId);

11. phone.setDataEnabled(enable);

12. }

这里的Phone是一个interface。在【Android架构Telephony篇】数据业务(1)总览提到，无线通信有TD-LTE/FDD-LTE/TD-SCDMA/WCDMA/EVDO/CDMA1X/GSM等等很多的网络制式，不同模块可以支持其中的一种或多种。它们之间的区别最简单的例子，比如常说的电信卡、联通卡等等。从软件层面进行抽象就是：

 

 

 

Phone的创建：

 

1. PhoneFactory.java (frameworks\opt\telephony\src\java\com\android\internal\telephony)

2. public static void makeDefaultPhone(Context context) {

3. PhoneBase phone = null;

4. int phoneType = TelephonyManager.getPhoneType(networkModes[i]);

5. if (phoneType == PhoneConstants.PHONE_TYPE_GSM) {

6. phone = new GSMPhone(context,

7. sCommandsInterfaces[i], sPhoneNotifier, i);

8. } else if (phoneType == PhoneConstants.PHONE_TYPE_CDMA) {

9. phone = new CDMALTEPhone(context,

10. sCommandsInterfaces[i], sPhoneNotifier, i);

11. }

12. }

 

 

这里就根据type创建不同的Phone，我们以GSMPhone为例，setDataEnabled()调用的就是：

 

1. GSMPhone.java (frameworks\opt\telephony\src\java\com\android\internal\telephony\gsm)

2. public void setDataEnabled(boolean enable) {

3. mDcTracker.setDataEnabled(enable);

4. }

mDcTracker是一个Handler，

 

 

 

1. DcTrackerBase.java (frameworks\opt\telephony\src\java\com\android\internal\telephony\dataconnection)

2. public void setDataEnabled(boolean enable) {

3. Message msg = obtainMessage(DctConstants.CMD_SET_USER_DATA_ENABLE);

4. msg.arg1 = enable ? 1 : 0;

5. sendMessage(msg);

6. }

7. public void handleMessage(Message msg) {

8. switch (msg.what) {

9. case DctConstants.CMD_SET_USER_DATA_ENABLE: {

10. final boolean enabled = (msg.arg1 == DctConstants.ENABLED) ? true : false;

11. onSetUserDataEnabled(enabled);

12. break;

13. }

14. }

15.  

16. DcTrackerBase#onSetUserDataEnabled()

17. -->DcTrackerBase#onTrySetupData()

 

DcTrackerBase发送CMD_SET_USER_DATA_ENABLE信息，并自己处理，最终调用到onTrySetupData()，实现onTrySetupData()的地方：

 

1. DcTracker.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)

2. protected boolean onTrySetupData(String reason) {

3. setupDataOnConnectableApns(reason);

4. return true;

5. }

setupDataOnConnectableApns()顾名思义就是使用可用的APN建立数据连接，之后：

 

1. DcTracker.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)

2. setupDataOnConnectableApns(reason, RetryFailures.ALWAYS);

3. -->trySetupData(apnContext, waitingApns);

4. ---->setupData(apnContext, radioTech);

5.  

6. private boolean setupData(ApnContext apnContext, int radioTech) {

7. // 用于连接DcTracker和DataConnection

8. DcAsyncChannel dcac = null;

9.  

10. if (dcac == null) {

11. // 获取/创建DcAsyncChannel对象

12. }

13.  

14. // 更新apnContext

15. apnContext.setDataConnectionAc(dcac);

16. apnContext.setApnSetting(apnSetting);

17. apnContext.setState(DctConstants.State.CONNECTING);

18. mPhone.notifyDataConnection(apnContext.getReason(), apnContext.getApnType());

19.  

20. // 拨号成功后发送EVENT_DATA_SETUP_COMPLETE信息

21. Message msg = obtainMessage();

22. msg.what = DctConstants.EVENT_DATA_SETUP_COMPLETE;

23. msg.obj = new Pair(apnContext, generation);

24. dcac.bringUp(apnContext, getInitialMaxRetry(), profileId, radioTech,

25. mAutoAttachOnCreation.get(), msg, generation);

26. return true;

27. }

 

调用DcAsyncChannel的bringUp()，向DataConnection发送建立连接消息EVENT_CONNECT：

 

1. DcAsyncChannel.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)

2. /**

3. * Bring up a connection to the apn and return an AsyncResult in onCompletedMsg.

4. * Used for cellular networks that use Acesss Point Names (APN) such

5. * as GSM networks.

6. */

7. public void bringUp(ApnContext apnContext, int initialMaxRetry, int profileId,

8. int rilRadioTechnology, boolean retryWhenSSChange, Message onCompletedMsg,

9. int connectionGeneration) {

10. sendMessage(DataConnection.EVENT_CONNECT,

11. new ConnectionParams(apnContext, initialMaxRetry, profileId,

12. rilRadioTechnology, retryWhenSSChange, onCompletedMsg,

13. connectionGeneration));

14. }

 

 

DataConnection处理EVENT_CONNECT：

1. DataConnection.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)

2. private class DcInactiveState extends State { -->a

3. public boolean processMessage(Message msg) {

4. case EVENT_CONNECT:

5. ConnectionParams cp = (ConnectionParams) msg.obj;

6. if (initConnection(cp)) { -->b

7. onConnect(mConnectionParams); -->c

8. transitionTo(mActivatingState);

9. } else {

10. log("DcInactiveState: msg.what=EVENT_CONNECT initConnection failed");

11. notifyConnectCompleted(cp, DcFailCause.UNACCEPTABLE_NETWORK_PARAMETER,

12. false);

13. }

14. retVal = HANDLED;

15. break;

16. }

17. }

a, DataConnection是一个状态机，其初始状态：

 

 

1. private DcInactiveState mInactiveState = new DcInactiveState();

2. private DataConnection() {

3. setInitialState(mInactiveState);

4. }

所以这里调用DcInactiveState类的processMessage()处理EVENT_CONNECT信息。

 

b, 检测参数合法性

c, 调用onConnect()启动连接建立

 

1. /**

2. * Begin setting up a data connection, calls setupDataCall

3. * and the ConnectionParams will be returned with the

4. * EVENT_SETUP_DATA_CONNECTION_DONE AsyncResul.userObj.

5. */

6. private void onConnect(ConnectionParams cp) {

7.  

8. // msg.obj will be returned in AsyncResult.userObj;

9. Message msg = obtainMessage(EVENT_SETUP_DATA_CONNECTION_DONE, cp);

10. msg.obj = cp;

11.  

12. mPhone.mCi.setupDataCall(

13. Integer.toString(cp.mRilRat + 2),

14. Integer.toString(cp.mProfileId),

15. mApnSetting.apn, mApnSetting.user, mApnSetting.password,

16. Integer.toString(authType),

17. protocol, msg);

18. }

mCi是一个CommandsInterface，实现它的是RIL：

 

 

1. RIL.java (opt\telephony\src\java\com\android\internal\telephony)

2. public final class RIL extends BaseCommands implements CommandsInterface {

3. }

这里，就来到了开篇流程图中的“RILJ”，在继续下去之前，稍微提下Android中本地socket通信。

 

(3)socket进程间通信

Linux中的socket除了可以用于不同机器之间的网络通信，还可以用于同一台机器的进程间通信。以Telephony为例，RILJ的java进程和RILC的c守护进程之间就是通过"/dev/socket/rild"这个socket进行通信的。

a, socket建立

 

1. RIL.java (opt\telephony\src\java\com\android\internal\telephony)

2. LocalSocket mSocket;

3. String rilSocket = "rild";

4. s = new LocalSocket();

5. l = new LocalSocketAddress(rilSocket, LocalSocketAddress.Namespace.RESERVED);

6. s.connect(l);

7.  

8. mSocket = s;

 

 

b, 数据发送

 

1. RIL.java (opt\telephony\src\java\com\android\internal\telephony)

2. class RILSender extends Handler implements Runnable {

3. @Override public void handleMessage(Message msg) {

4. switch (msg.what) {

5. case EVENT_SEND:

6. try {

7. LocalSocket s;

8. s = mSocket;

9.  

10. synchronized (mRequestList) {

11. mRequestList.append(rr.mSerial, rr);

12. }

13.  

14. byte[] data;

15.  

16. data = rr.mParcel.marshall();

17. rr.mParcel.recycle();

18. rr.mParcel = null;

19.  

20. // parcel length in big endian

21. dataLength[0] = dataLength[1] = 0;

22. dataLength[2] = (byte)((data.length >> 8) & 0xff);

23. dataLength[3] = (byte)((data.length) & 0xff);

24.  

25. s.getOutputStream().write(dataLength);

26. s.getOutputStream().write(data);

27. }

28. }

29. }

c, 数据接收

 

 

 

1. RIL.java (opt\telephony\src\java\com\android\internal\telephony)

2. class RILReceiver implements Runnable {

3. try {

4. InputStream is = mSocket.getInputStream();

5. for (;;) {

6. Parcel p;

7. length = readRilMessage(is, buffer);

8. if (length < 0) {

9. // End-of-stream reached

10. break;

11. }

12.  

13. p = Parcel.obtain();

14. p.unmarshall(buffer, 0, length);

15. p.setDataPosition(0);

16. processResponse(p); // 数据处理

17. p.recycle();

18. }

19. }

20. }

有了这个知识，RILJ就容易理解了。

 

(4)RILJ

 

1. RIL.java (opt\telephony\src\java\com\android\internal\telephony)

2. @Override

3. public void setupDataCall(String radioTechnology, String profile, String apn,

4. String user, String password, String authType, String protocol,

5. Message result) {

6. RILRequest rr

7. = RILRequest.obtain(RIL_REQUEST_SETUP_DATA_CALL, result);

8.  

9. rr.mParcel.writeInt(7);

10.  

11. rr.mParcel.writeString(radioTechnology);

12. rr.mParcel.writeString(profile);

13. rr.mParcel.writeString(apn);

14. rr.mParcel.writeString(user);

15. rr.mParcel.writeString(password);

16. rr.mParcel.writeString(authType);

17. rr.mParcel.writeString(protocol);

18.  

19. send(rr);

20. }

21.  

22. private void send(RILRequest rr) {

23. Message msg;

24.  

25. if (mSocket == null) {

26. rr.onError(RADIO_NOT_AVAILABLE, null);

27. rr.release();

28. return;

29. }

30.  

31. msg = mSender.obtainMessage(EVENT_SEND, rr);

32.  

33. acquireWakeLock();

34.  

35. msg.sendToTarget();

36. }