android系统 Ethernet 解析

最新推荐文章于 2025-03-21 20:30:48 发布

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最新推荐文章于 2025-03-21 20:30:48 发布

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分类专栏： andriod 系统源码 framework 文章标签： android ethernet

本文链接：https://blog.youkuaiyun.com/liufuliang163/article/details/72772246

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在公司一款产品上需要需要添加有线网口，所以系统需要做相应的支持，找到一个支持的有线网口的系统，将其中软件部分做简单分析：

首先：功能方面，要能够设置有线网络的IP地址，子网掩码，网关，DNS等信息，这些功能由 Etnernet 这个 APP实现；

系统方面，对于已经设置好的信息，断电重启之后不能丢失，还能继续保持有效，所以需要添加一个系统服务 EthernetService

其次，EthernetService的启动入口， \frameworks\base\services\java\com\android\server\ConnectivityService.java 其构造类

public ConnectivityService(Context context, INetworkManagementService netManager,
INetworkStatsService statsService, INetworkPolicyManager policyManager,
NetworkFactory netFactory)

。

for (int targetNetworkType : mPriorityList) {
final NetworkConfig config = mNetConfigs[targetNetworkType];
final NetworkStateTracker tracker;
try {
tracker = netFactory.createTracker(targetNetworkType, config);
mNetTrackers[targetNetworkType] = tracker;
if (targetNetworkType == ConnectivityManager.TYPE_ETHERNET) {
EthernetService ethernet = new EthernetService(context, (EthernetStateTracker)tracker);
ServiceManager.addService(Context.ETH_SERVICE, ethernet);
}
Slog.d(TAG, "*******targetNetworkType="+targetNetworkType);
} catch (IllegalArgumentException e) {
Slog.e(TAG, "Problem creating " + getNetworkTypeName(targetNetworkType)
+ " tracker: " + e);
continue;
}

tracker.startMonitoring(context, mTrackerHandler);

if (config.isDefault()) {
tracker.reconnect();
}
}

上面的黑体字代码是实现Ethernet 功能的核心，具体分析如下

1. tracker = netFactory.createTracker(targetNetworkType, config);

创建网络状态追踪器

@Override
public NetworkStateTracker createTracker(int targetNetworkType, NetworkConfig config) {
switch (config.radio) {
case TYPE_WIFI:
return new WifiStateTracker(targetNetworkType, config.name);
case TYPE_MOBILE:
return new MobileDataStateTracker(targetNetworkType, config.name);
case TYPE_DUMMY:
return new DummyDataStateTracker(targetNetworkType, config.name);
case TYPE_BLUETOOTH:
return BluetoothTetheringDataTracker.getInstance();
case TYPE_WIMAX:
return makeWimaxStateTracker(mContext, mTrackerHandler);
case TYPE_ETHERNET:
//return EthernetDataTracker.getInstance();
return new EthernetStateTracker(targetNetworkType, config.name);
default:
throw new IllegalArgumentException(
"Trying to create a NetworkStateTracker for an unknown radio type: "
+ config.radio);
}
}
}

2. 创建并添加网络服务

EthernetService ethernet = new EthernetService(context, (EthernetStateTracker)tracker);
ServiceManager.addService(Context.ETH_SERVICE, ethernet);

\frameworks\base\services\java\com\android\server\EthernetService.java

private int mEthState= EthernetManager.ETH_STATE_UNKNOWN;
//public static final int ETH_STATE_UNKNOWN = 0;

public EthernetService(Context context, EthernetStateTracker Tracker){
mTracker = Tracker;
mContext = context;

isEthEnabled = getPersistedState();
Slog.v(TAG,"Ethernet dev enabled " + isEthEnabled );
getDeviceNameList();
setEthState(isEthEnabled);
//registerForBroadcasts();
Slog.v(TAG, "Trigger the ethernet monitor");
mTracker.StartPolling();
mDelayedHandler = new Handler();
isEthernetServiceInited = true;
}

其核心是 setEthState，即开关网络

3. tracker.startMonitoring(context, mTrackerHandler);

启动网络状态监控，核心是

frameworks\base\ethernet\java\android\net\ethernet\EthernetMonitor.java

class MonitorThread extends Thread {

public MonitorThread() {
super("EthMonitor");
}

public void run() {
int index;
int i;

//noinspection InfiniteLoopStatement
for (;;) {
if (DEBUG) Slog.i(TAG, "go poll events");
String eventName = EthernetNative.waitForEvent();

if (eventName == null) {
continue;
}
if (DEBUG) Slog.i(TAG, "got event " + eventName);
/*
* Map event name into event enum
*/
String [] events = eventName.split(":");
index = events.length;
if (index < 2)
continue;
i = 0;
while (index != 0 && i < index-1) {

int event = 0;
if (DEBUG) Slog.i(TAG,"dev: " + events[i] + " ev " + events[i+1]);
int cmd =Integer.parseInt(events[i+1]);
if ( cmd == DEL_LINK) {
event = DISCONNECTED;
handleEvent(events[i],event);
}
else if (cmd == ADD_ADDR ) {
event = CONNECTED;
handleEvent(events[i],event);
} else if (cmd == NEW_LINK) {
event = PHYUP;
handleEvent(events[i],event);
}
i = i + 2;
}
}
}
/**
* Handle all supplicant events except STATE-CHANGE
* @param event the event type
* @param remainder the rest of the string following the
* event name and " — "
*/
void handleEvent(String ifname,int event) {
switch (event) {
case DISCONNECTED:
mTracker.notifyStateChange(ifname,NetworkInfo.DetailedState.DISCONNECTED);
break;
case CONNECTED:
mTracker.notifyStateChange(ifname,NetworkInfo.DetailedState.CONNECTED);
break;
case PHYUP:
mTracker.notifyPhyConnected(ifname);
break;
default:
mTracker.notifyStateChange(ifname,NetworkInfo.DetailedState.FAILED);
}
}