-
Android: 6.0
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Desktop: Ubuntu 15.04
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更新:2017-04-27
Android设备中完整的移动通讯系统构成:
(1)Hardware
这里提到的无线通信模组是一种支持TD-LTE/FDD-LTE/TD-SCDMA/WCDMA/EVDO/CDMA1X/GSM等等网络制式的通信模块,能够为用户提供高速的无线数据、互联网接入等业务,具备语音、分组数据、短信功能,彩信等功能。提供这些功能使用服务的就是联通/移动/电信等运营商,通过SIM卡注册到各自的网络中,付费使用。
(2)Kernel
内核中实现访问无线通信模组的数据通道,比如对于串口类模组就可以为/dev/ttyS0(/dev/ttyS1...),USB接口的为/dev/ttyUSB0(/dev/ttyUSB1...)等。
而要使用模组的网络功能,还必须实现网络功能的通信协议,比如常见的PPP(Point-to-Point Protocol):
-
PPP is the protocol used for establishing internet links over dial-up modems, DSL connections, and many other types of point-to-point links. The
为直观故,我们看下通过PPP建立网络连接的log:
最后一行返回status为0,说明网络建立成功。
同时,它也显示了本地IP、远程IP、DNS等网络信息。在Android拨号过程中,用到的两个重要文件是/data/connect和/etc/ppp/ip-up。
这时可以adb shell进入系统,看下网络:
或:
(3)Framework
该层的Telephony子系统完成无线通信模块所有功能的具体实现,同时为应用开发人员提供使用接口。
(4)App
作为App开发人员,调用Telephony的API,实现具体功能的App工用户使用。
Android的Telephony子系统也是非常复杂的,涉及很多方面。我们以数据业务为分析入口,从上到下走一遍框图中的流程。
http://blog.csdn.net/u013686019/article/details/49719897
Telephony的Overview见:
【Android架构Telephony篇】数据业务(1)总览
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:
-
DataUsageSummary.java (packages\apps\settings\src\com\android\settings)
-
private void setMobileDataEnabled(int subId, boolean enabled) {
-
mTelephonyManager.setDataEnabled(subId, enabled);
-
}
TelephonyManager作为"phone"系统服务的管理类,其获取方式可以:
-
DataUsageSummary#onCreate()
-
-->mTelephonyManager = TelephonyManager.from(context);
-
-
TelephonyManager.java (frameworks\base\telephony\java\android\telephony)
-
public static TelephonyManager from(Context context) {
-
return (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
-
}
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:
-
TelephonyManager.java (frameworks\base\telephony\java\android\telephony)
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private ITelephony getITelephony() {
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return ITelephony.Stub.asInterface(ServiceManager.getService(Context.TELEPHONY_SERVICE));
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}
-
-
public void setDataEnabled(int subId, boolean enable) {
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ITelephony telephony = getITelephony();
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telephony.setDataEnabled(subId, enable);
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}
Telephony提供的操作无线模组的方法可以通过ITelephony.aidl文件查看:
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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:
-
PhoneApp.java (packages\services\telephony\src\com\android\phone)
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public class PhoneApp extends Application {}
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PhoneApp#onCreate()
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-->PhoneGlobals#onCreate()
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---->PhoneInterfaceManager#init()
-
------>PhoneInterfaceManager#publish()
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-------->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:
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# service list
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Found 102 services:
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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:
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PhoneInterfaceManager.java (packages\services\telephony\src\com\android\phone)
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/**
-
* Set mobile data enabled
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* Used by the user through settings etc to turn on/off mobile data
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*/
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@Override
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public void setDataEnabled(int subId, boolean enable) {
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enforceModifyPermission(); -->a
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int phoneId = mSubscriptionController.getPhoneId(subId); -->b
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Phone phone = PhoneFactory.getPhone(phoneId);
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phone.setDataEnabled(enable);
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}
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:
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PhoneFactory.java (frameworks\opt\telephony\src\java\com\android\internal\telephony)
-
public static void makeDefaultPhone(Context context) {
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PhoneBase phone = null;
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int phoneType = TelephonyManager.getPhoneType(networkModes[i]);
-
if (phoneType == PhoneConstants.PHONE_TYPE_GSM) {
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phone = new GSMPhone(context,
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sCommandsInterfaces[i], sPhoneNotifier, i);
-
} else if (phoneType == PhoneConstants.PHONE_TYPE_CDMA) {
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phone = new CDMALTEPhone(context,
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sCommandsInterfaces[i], sPhoneNotifier, i);
-
}
-
}
这里就根据type创建不同的Phone,我们以GSMPhone为例,setDataEnabled()调用的就是:
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GSMPhone.java (frameworks\opt\telephony\src\java\com\android\internal\telephony\gsm)
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public void setDataEnabled(boolean enable) {
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mDcTracker.setDataEnabled(enable);
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}
mDcTracker是一个Handler,
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DcTrackerBase.java (frameworks\opt\telephony\src\java\com\android\internal\telephony\dataconnection)
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public void setDataEnabled(boolean enable) {
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Message msg = obtainMessage(DctConstants.CMD_SET_USER_DATA_ENABLE);
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msg.arg1 = enable ? 1 : 0;
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sendMessage(msg);
-
}
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public void handleMessage(Message msg) {
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switch (msg.what) {
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case DctConstants.CMD_SET_USER_DATA_ENABLE: {
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final boolean enabled = (msg.arg1 == DctConstants.ENABLED) ? true : false;
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onSetUserDataEnabled(enabled);
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break;
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}
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}
-
-
DcTrackerBase#onSetUserDataEnabled()
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-->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:
-
DcTracker.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)
-
protected boolean onTrySetupData(String reason) {
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setupDataOnConnectableApns(reason);
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return true;
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}
setupDataOnConnectableApns()顾名思义就是使用可用的APN建立数据连接,之后:
-
DcTracker.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)
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setupDataOnConnectableApns(reason, RetryFailures.ALWAYS);
-
-->trySetupData(apnContext, waitingApns);
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---->setupData(apnContext, radioTech);
-
-
private boolean setupData(ApnContext apnContext, int radioTech) {
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// 用于连接DcTracker和DataConnection
-
DcAsyncChannel dcac = null;
-
-
if (dcac == null) {
-
// 获取/创建DcAsyncChannel对象
-
}
-
-
// 更新apnContext
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apnContext.setDataConnectionAc(dcac);
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apnContext.setApnSetting(apnSetting);
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apnContext.setState(DctConstants.State.CONNECTING);
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mPhone.notifyDataConnection(apnContext.getReason(), apnContext.getApnType());
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-
// 拨号成功后发送EVENT_DATA_SETUP_COMPLETE信息
-
Message msg = obtainMessage();
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msg.what = DctConstants.EVENT_DATA_SETUP_COMPLETE;
-
msg.obj = new Pair<ApnContext, Integer>(apnContext, generation);
-
dcac.bringUp(apnContext, getInitialMaxRetry(), profileId, radioTech,
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mAutoAttachOnCreation.get(), msg, generation);
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return true;
-
}
调用DcAsyncChannel的bringUp(),向DataConnection发送建立连接消息EVENT_CONNECT:
-
DcAsyncChannel.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)
-
/**
-
* Bring up a connection to the apn and return an AsyncResult in onCompletedMsg.
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* Used for cellular networks that use Acesss Point Names (APN) such
-
* as GSM networks.
-
*/
-
public void bringUp(ApnContext apnContext, int initialMaxRetry, int profileId,
-
int rilRadioTechnology, boolean retryWhenSSChange, Message onCompletedMsg,
-
int connectionGeneration) {
-
sendMessage(DataConnection.EVENT_CONNECT,
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new ConnectionParams(apnContext, initialMaxRetry, profileId,
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rilRadioTechnology, retryWhenSSChange, onCompletedMsg,
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connectionGeneration));
-
}
DataConnection处理EVENT_CONNECT:
-
DataConnection.java (opt\telephony\src\java\com\android\internal\telephony\dataconnection)
-
private class DcInactiveState extends State { -->a
-
public boolean processMessage(Message msg) {
-
case EVENT_CONNECT:
-
ConnectionParams cp = (ConnectionParams) msg.obj;
-
if (initConnection(cp)) {<span style="font-family:Courier New;"> --></span>b
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onConnect(mConnectionParams); -->c
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transitionTo(mActivatingState);
-
} else {
-
log("DcInactiveState: msg.what=EVENT_CONNECT initConnection failed");
-
notifyConnectCompleted(cp, DcFailCause.UNACCEPTABLE_NETWORK_PARAMETER,
-
false);
-
}
-
retVal = HANDLED;
-
break;
-
}
-
}
a, DataConnection是一个状态机,其初始状态:
-
private DcInactiveState mInactiveState = new DcInactiveState();
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private DataConnection() {
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setInitialState(mInactiveState);
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}
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
-
/**
-
* Begin setting up a data connection, calls setupDataCall
-
* and the ConnectionParams will be returned with the
-
* EVENT_SETUP_DATA_CONNECTION_DONE AsyncResul.userObj.
-
*/
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private void onConnect(ConnectionParams cp) {
-
-
// msg.obj will be returned in AsyncResult.userObj;
-
Message msg = obtainMessage(EVENT_SETUP_DATA_CONNECTION_DONE, cp);
-
msg.obj = cp;
-
-
mPhone.mCi.setupDataCall(
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Integer.toString(cp.mRilRat + 2),
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Integer.toString(cp.mProfileId),
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mApnSetting.apn, mApnSetting.user, mApnSetting.password,
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Integer.toString(authType),
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protocol, msg);
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}
mCi是一个CommandsInterface,实现它的是RIL:
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RIL.java (opt\telephony\src\java\com\android\internal\telephony)
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public final class RIL extends BaseCommands implements CommandsInterface {
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}
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
-
RIL.java (opt\telephony\src\java\com\android\internal\telephony)
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LocalSocket mSocket;
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String rilSocket = "rild";
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s = new LocalSocket();
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l = new LocalSocketAddress(rilSocket, LocalSocketAddress.Namespace.RESERVED);
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s.connect(l);
-
-
mSocket = s;
b, 数据发送
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RIL.java (opt\telephony\src\java\com\android\internal\telephony)
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class RILSender extends Handler implements Runnable {
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@Override public void handleMessage(Message msg) {
-
switch (msg.what) {
-
case EVENT_SEND:
-
try {
-
LocalSocket s;
-
s = mSocket;
-
-
synchronized (mRequestList) {
-
mRequestList.append(rr.mSerial, rr);
-
}
-
-
byte[] data;
-
-
data = rr.mParcel.marshall();
-
rr.mParcel.recycle();
-
rr.mParcel = null;
-
-
// parcel length in big endian
-
dataLength[0] = dataLength[1] = 0;
-
dataLength[2] = (byte)((data.length >> 8) & 0xff);
-
dataLength[3] = (byte)((data.length) & 0xff);
-
-
s.getOutputStream().write(dataLength);
-
s.getOutputStream().write(data);
-
}
-
}
-
}
c, 数据接收
-
RIL.java (opt\telephony\src\java\com\android\internal\telephony)
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class RILReceiver implements Runnable {
-
try {
-
InputStream is = mSocket.getInputStream();
-
for (;;) {
-
Parcel p;
-
length = readRilMessage(is, buffer);
-
if (length < 0) {
-
// End-of-stream reached
-
break;
-
}
-
-
p = Parcel.obtain();
-
p.unmarshall(buffer, 0, length);
-
p.setDataPosition(0);
-
processResponse(p); // 数据处理
-
p.recycle();
-
}
-
}
-
}
有了这个知识,RILJ就容易理解了。
(4)RILJ
-
RIL.java (opt\telephony\src\java\com\android\internal\telephony)
-
@Override
-
public void setupDataCall(String radioTechnology, String profile, String apn,
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String user, String password, String authType, String protocol,
-
Message result) {
-
RILRequest rr
-
= RILRequest.obtain(RIL_REQUEST_SETUP_DATA_CALL, result);
-
-
rr.mParcel.writeInt(7);
-
-
rr.mParcel.writeString(radioTechnology);
-
rr.mParcel.writeString(profile);
-
rr.mParcel.writeString(apn);
-
rr.mParcel.writeString(user);
-
rr.mParcel.writeString(password);
-
rr.mParcel.writeString(authType);
-
rr.mParcel.writeString(protocol);
-
-
send(rr);
-
}
-
-
private void send(RILRequest rr) {
-
Message msg;
-
-
if (mSocket == null) {
-
rr.onError(RADIO_NOT_AVAILABLE, null);
-
rr.release();
-
return;
-
}
-
-
msg = mSender.obtainMessage(EVENT_SEND, rr);
-
-
acquireWakeLock();
-
-
msg.sendToTarget();
-
}
无需解释。
【Android架构Telephony篇】数据业务(3)RILC
http://blog.csdn.net/u013686019/article/details/53580878
三、Telephony数据业务的RILC层
现在,建立移动数据业务的任务通过socket传递给C/C++的RIL进行处理了:
-
hardware\ril\rild\rild.c:
-
int main(int argc, char **argv)
-
{
-
char libPath[PROPERTY_VALUE_MAX];
-
-
/**启动rild并解析/init.rc传进来的参数:
-
* rild -l /system/lib/libreference-ril.so -- -d /dev/mux2
-
*/
-
for (i = 1; i < argc ;) {
-
if (0 == strcmp(argv[i], "-l") && (argc - i > 1)) {
-
rilLibPath = argv[i + 1]; // ril库的路径,即"/system/lib/libreference-ril.so"
-
i += 2;
-
} else if (0 == strcmp(argv[i], "--")) {
-
i++;
-
hasLibArgs = 1;
-
break;
-
} else {
-
usage(argv[0]);
-
}
-
}
-
-
/** 启动/system/bin/muxd,生成/dev/mux2节点 */
-
startmux(bpID);
-
-
/** 加载传进来的/system/lib/libreference-ril.so库*/
-
dlHandle = dlopen(rilLibPath, RTLD_NOW);
-
-
if (dlHandle == NULL) {
-
RLOGE("dlopen failed: %s", dlerror());
-
exit(-1);
-
}
-
-
/** 事件监听 */
-
RIL_startEventLoop();
-
-
rilInit = (const RIL_RadioFunctions *(*)(const struct RIL_Env *, int, char **))dlsym(dlHandle, "RIL_Init");
-
-
if (rilInit == NULL) {
-
RLOGE("RIL_Init not defined or exported in %s\n", rilLibPath);
-
exit(-1);
-
}
-
-
/**注册事件回调函数
-
*static struct RIL_Env s_rilEnv = {
-
* RIL_onRequestComplete,
-
* RIL_onUnsolicitedResponse,
-
* RIL_requestTimedCallback
-
*};
-
*/
-
funcs = rilInit(&s_rilEnv, argc, rilArgv);
-
-
RIL_register(funcs);
-
done:
-
while(1) {
-
sleep(0x00ffffff);
-
}
-
}
rild用来对RIL进行管理。对于不同的Modem,尤其不同无线通信技术(GSM、CDMA)之间,其差别是很大的;就算是同种技术的Modem,不同厂商也有区别。所以管理部分处理它们共通的业务逻辑,而把具体的实现交给xxxril.so。管理部分涉及文件:hardware\ril\libril\ril.cpp、hardware\ril\libril\ril_event.cpp,本文不对该部分进行分析。
/system/lib/libreference-ril.so库处理AT指令相关操作,/dev/mux2用作数据通道。我们知道,Modem和CPU之间是通过串口连接的,为了使AT指令和数据分开管理,系统对串口进行了复用。原理和实现参见:hardware/ril/gsm0710muxd/src/gsm0710muxd.c。
回到数据业务建立上面。在RIL的具体实现上,每一个操作,比如短信、电话、查询信号强度等都有独有的Request,且RILC/C++和RILJava定义一致。建立数据连接的Request是RIL_REQUEST_SETUP_DATA_CALL:
-
frameworks\opt\telephony\src\java\com\android\internal\telephony\RIL.java
-
RILRequest rr = RILRequest.obtain(RIL_REQUEST_SETUP_DATA_CALL, result);
响应该request的地方是:
-
hardware\ril\reference-ril\reference-ril.c
-
/**
-
* Call from RIL to us to make a RIL_REQUEST
-
*/
-
static void onRequest (int request, void *data, size_t datalen, RIL_Token t)
-
{
-
switch (request) {
-
case RIL_REQUEST_SETUP_DATA_CALL:
-
requestSetupDataCall(data, datalen, t);
-
break;
-
}
-
}
-
-
static void requestSetupDataCall(void *data, size_t datalen, RIL_Token t)
-
{
-
char value[PROPERTY_VALUE_MAX] = "";
-
char dns1[64]="";
-
char dns2[64]="";
-
char *cmd;
-
int err,i,fd;
-
-
char *response[3] = { "ppp0", "IP", ip_address };
-
RIL_Data_Call_Response_v6 response_v6;
-
int mypppstatus;
-
char strTemp[32];
-
ATResponse *p_response = NULL;
-
char *dialup = NULL;
-
int cid = 1;
-
int channel = 0;
-
char dev_path[32];
-
char gateway[PROPERTY_VALUE_MAX] = "";
-
-
const char* radioTechnology = ((const char**)data)[0];
-
const char* profile = ((const char**)data)[1];
-
const char* apn = ((const char**)data)[2];
-
const char* user = ((const char**)data)[3];
-
const char* password = ((const char**)data)[4];
-
const char* authType = ((const char**)data)[5];
-
char *auth_option;
-
memset(ip_address,0,32);
-
LOGD("radioTechnology:%s", radioTechnology);
-
LOGD("profile:%s", profile);
-
LOGD("apn:%s", apn);
-
LOGD("user:%s", user);
-
LOGD("password:%s", password);
-
LOGD("authType:%s", authType);
-
-
/**
-
* 数据业务建立的方式,依据不同Modem而有所不同
-
*/
-
asprintf(&cmd, "/etc/ppp/call-pppd "
-
"\"%s 115200\" " // $1
-
"\"novj novjccomp noccp ipcp-accept-local ipcp-accept-remote\" " // $2
-
"\"%s\" \"%s\" " // $3 $4
-
"\"%s\" \"%s\" &", // $5 $6
-
s_pppChannel, user, password, conn_script, disconn_script);
-
ret = system(cmd);
-
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
-
at_response_free(p_response);
-
}
据业务建立的方式,依据不同Modem而有所不同,对于PPP方式,Android下的一个实现是通过/etc/ppp/call-pppd脚本进行:
-
/etc/ppp/call-pppd
-
#!/system/bin/sh
-
# An unforunate wrapper script
-
# so that the exit code of pppd may be retrieved
-
-
#PPPD_PID=""
-
PPPD_EXIT=""
-
-
/system/bin/setprop "net.gprs.ppp-exit" ""
-
-
/system/bin/pppd $1 debug defaultroute noauth nodetach nocrtscts $2 noipdefault usepeerdns user "$3" password "$4" connect "$5" disconnect "$6"
-
-
PPPD_EXIT=$?
-
#PPPD_PID=$!
-
-
/system/bin/setprop "net.gprs.ppp-exit" "$PPPD_EXIT"
call-pppd脚本需要我们传进来6个参数,比如:
-
asprintf(&cmd, "/etc/ppp/call-pppd "
-
"\"%s 115200\" " // $1
-
"\"novj novjccomp noccp ipcp-accept-local ipcp-accept-remote\" " // $2
-
"\"%s\" \"%s\" " // $3 $4
-
"\"%s\" \"%s\" &", // $5 $6
-
s_pppChannel, user, password, conn_script, disconn_script);
-
ret = system(cmd);
system(const char *command)函数用来执行call-pppd脚本,log:
至此,数据业务建立完成,通过ifconfig命令查看,生成由ppp设备节点。
转自 http://blog.csdn.net/u013686019/article/details/53580878