Android5.0以太网流程源码情景分析

logcat -s TCL_EthernetManager EthernetManager EthernetService EthernetServiceImpl EthernetNetworkFactory EthernetConfigStore TCL_EthernetDevInfo CommandListener ConnectivityService NetworkSettingsActivity Ethernetd dhcpcd NetworkMonitorNetworkAgentInfo NetworkManagementService NetdConnector NativeDaemonConnector Guide NetworkMonitorNetworkAgentInfo

一、启动流程

frameworks/base/services/java/com/android/server/SystemServer.java

public final class SystemServer {
  private static final String ETHERNET_SERVICE_CLASS =
            "com.android.server.ethernet.EthernetService";
  public static void main(String[] args) {
    new SystemServer().run();
  }
  private void run() {
    startOtherServices();
  }
  private void startOtherServices() {
    if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_ETHERNET)) {
                    mSystemServiceManager.startService(ETHERNET_SERVICE_CLASS);
    }
  }
}

frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetService.java

public final class EthernetService extends SystemService {
    private static final String TAG = "EthernetService";
    final EthernetServiceImpl mImpl;
    public EthernetService(Context context) {
        super(context);
        mImpl = new EthernetServiceImpl(context);
    }
    @Override
    public void onStart() {
        Log.i(TAG, "Registering service " + Context.ETHERNET_SERVICE);
        publishBinderService(Context.ETHERNET_SERVICE, mImpl);
    }
    @Override
    public void onBootPhase(int phase) {
        if (phase == SystemService.PHASE_SYSTEM_SERVICES_READY) {
            mImpl.start();
        }
    }
}

frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetServiceImpl.java

public class EthernetServiceImpl extends IEthernetManager.Stub {
  public EthernetServiceImpl(Context context) {
    mContext = context;
    Log.i(TAG, "Creating EthernetConfigStore");
    mEthernetConfigStore = new EthernetConfigStore();
    mIpConfiguration = mEthernetConfigStore.readIpAndProxyConfigurations();
    Log.i(TAG, "Read stored IP configuration: " + mIpConfiguration);
    IBinder b = ServiceManager.getService(Context.NETWORKMANAGEMENT_SERVICE);
    mNMService = INetworkManagementService.Stub.asInterface(b);
    mTracker = new EthernetNetworkFactory();
  }
  public void start() {
    mCM = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
    HandlerThread handlerThread = new HandlerThread("EthernetServiceThread");
    handlerThread.start();
    mHandler = new Handler(handlerThread.getLooper());
    mEnabled = getPersistedState();
    Log.i(TAG, "Ethernet Persisted Enabled " + mEnabled);
    setState(mEnabled);  //重要
  }
  public synchronized void setState(int state) {
    enforceChangePermission();
    Log.i(TAG, "setState from mState=" + mState + " to state=" + state);
    if (mState != state) {
      mState = state;
      if (state == EthernetManager.ETHERNET_STATE_DISABLED) {
        setPersistedState(EthernetManager.ETHERNET_STATE_DISABLED);
        mTracker.stopInterface();
        mStarted.set(false);
      } else {
        setPersistedState(EthernetManager.ETHERNET_STATE_ENABLED);
        mTracker.stop();
        mTracker.start(mContext, mHandler);
        mStarted.set(true);
      }
    }
  }
}

frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetNetworkFactory.java

class EthernetNetworkFactory {
  EthernetNetworkFactory() {
    mNetworkInfo = new NetworkInfo(ConnectivityManager.TYPE_ETHERNET, 0, NETWORK_TYPE, "");
    mLinkProperties = new LinkProperties();
    initNetworkCapabilities();
  }
  public synchronized void start(Context context, Handler target) {
    IBinder b = ServiceManager.getService(Context.NETWORKMANAGEMENT_SERVICE);
    mNMService = INetworkManagementService.Stub.asInterface(b);
    mEthernetManager = (EthernetManager) context.getSystemService(Context.ETHERNET_SERVICE);
    mFactory = new LocalNetworkFactory(NETWORK_TYPE, context, target.getLooper());
    mFactory.setCapabilityFilter(mNetworkCapabilities);
    mFactory.setScoreFilter(-1); // this set high when we have an iface
    mFactory.register();
    /*
    public void register() { 
      if (DBG) log("Registering NetworkFactory"); 
      if (mMessenger == null) { 
        mMessenger = new Messenger(this); 
        ConnectivityManager.from(mContext).registerNetworkFactory(mMessenger, LOG_TAG); 
      } 
    } 
    frameworks/base/services/core/java/com/android/server/ConnectivityService.java 
    public void registerNetworkFactory(Messenger messenger, String name) { 
      NetworkFactoryInfo nfi = new NetworkFactoryInfo(name, messenger, new AsyncChannel()); 
      mHandler.sendMessage(mHandler.obtainMessage(EVENT_REGISTER_NETWORK_FACTORY, nfi)); 
    } 
    private class InternalHandler extends Handler { 
      public void handleMessage(Message msg) { 
        case EVENT_REGISTER_NETWORK_FACTORY: { 
          handleRegisterNetworkFactory((NetworkFactoryInfo)msg.obj); 
          break; 
        } 
      } 
    } 
    private void handleRegisterNetworkFactory(NetworkFactoryInfo nfi) { 
      if (DBG) log("Got NetworkFactory Messenger for " + nfi.name); 
      mNetworkFactoryInfos.put(nfi.messenger, nfi); 
      nfi.asyncChannel.connect(mContext, mTrackerHandler, nfi.messenger); 
    }
    */
    mInterfaceObserver = new InterfaceObserver();
    try {
      mNMService.registerObserver(mInterfaceObserver);
    } catch (RemoteException e) {
      Log.e(TAG, "Could not register InterfaceObserver " + e);
    }
    updateInterfaceState(iface, true); //注册
  }
  private void updateInterfaceState(String iface, boolean up) {
    updateAgent();
    mFactory.setScoreFilter(up ? NETWORK_SCORE : -1); //设置scroe值；这个是网络优先级判断依据
  }
  public void updateAgent() {
    mNetworkAgent.sendNetworkInfo(mNetworkInfo);
  }
}

2.ETHERNET监听NETD进程的socket

init.rc

service netd /system/bin/netd
    class main
    socket netd stream 0660 root system
    socket dnsproxyd stream 0660 root inet
    socket mdns stream 0660 root system
    socket fwmarkd stream 0660 root inet

frameworks/base/services/core/java/com/android/server/NetworkManagementService.java

public static NetworkManagementService create(Context context) throws InterruptedException {
  return create(context, NETD_SOCKET_NAME);
  /*
  private static final String NETD_SOCKET_NAME = "netd";
  */
}

private NetworkManagementService(Context context, String socket) {
  mConnector = new NativeDaemonConnector(
                new NetdCallbackReceiver(), socket, 10, NETD_TAG, 160, wl,
                FgThread.get().getLooper());
  /*
  frameworks/base/services/core/java/com/android/server/NativeDaemonConnector.java
  public void run() {
    mCallbackHandler = new Handler(mLooper, this);
    while (true) {
      try {
        listenToSocket();
      } catch (Exception e) {
        loge("Error in NativeDaemonConnector: " + e);
        SystemClock.sleep(5000);
      }
    }
  }
  private void listenToSocket() throws IOException {
    LocalSocketAddress address = determineSocketAddress();
    mCallbackHandler.sendMessage();
  }
  public boolean handleMessage(Message msg) {
    mCallbacks.onEvent
  }
  */
}

private class NetdCallbackReceiver implements INativeDaemonConnectorCallbacks {
  public boolean onEvent(int code, String raw, String[] cooked) {
    notifyInterfaceAdded(cooked[3]);
    ......
    notifyInterfaceRemoved(cooked[3]);
    ......
    notifyInterfaceStatusChanged(cooked[3], cooked[4].equals("up"));
    ......
    notifyInterfaceLinkStateChanged(cooked[3], cooked[4].equals("up"));
  }
  private void notifyInterfaceLinkStateChanged(String iface, boolean up) {
    mObservers.getBroadcastItem(i).interfaceLinkStateChanged(iface, up);
  }
}

frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetNetworkFactory.java

private class InterfaceObserver extends BaseNetworkObserver {
  public void interfaceLinkStateChanged(String iface, boolean up) {
    updateInterfaceState(iface, up);
  }
}

private void updateInterfaceState(String iface, boolean up) {
 mFactory.setScoreFilter(up ? NETWORK_SCORE : -1);
}

frameworks/base/core/java/android/net/NetworkFactory.java

public void setScoreFilter(int score) {
  sendMessage(obtainMessage(CMD_SET_SCORE, score, 0));
}

public void handleMessage(Message msg) {
  case CMD_SET_SCORE: {
    handleSetScore(msg.arg1);
    break;
  }
}

private void handleSetScore(int score) {
  mScore = score;
  evalRequests();
}

private void evalRequests() {
  for (int i = 0; i < mNetworkRequests.size(); i++) {
    NetworkRequestInfo n = mNetworkRequests.valueAt(i);
    evalRequest(n);
  }
}

private void evalRequest(NetworkRequestInfo n) {
  needNetworkFor(n.request, n.score);
}

protected void needNetworkFor(NetworkRequest networkRequest, int score) {
  if (++mRefCount == 1) startNetwork();
}

frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetNetworkFactory.java

private class LocalNetworkFactory extends NetworkFactory {
  LocalNetworkFactory(String name, Context context, Looper looper) {
    super(looper, context, name, new NetworkCapabilities());
  }
  protected void startNetwork() {
    onRequestNetwork();
  }
  protected void stopNetwork() {
  }
}

public void onRequestNetwork() {
  Thread dhcpThread = new Thread(new Runnable() {
    public void run() {
      DhcpResults dhcpResults = new DhcpResults(); //DHCP相关
      if (!NetworkUtils.runDhcp(mIface, dhcpResults)) {
        /*
        frameworks/base/core/java/android/net/NetworkUtils.java
        public native static boolean runDhcp(String interfaceName, DhcpResults dhcpResults);
        frameworks/base/core/jni/android_net_NetUtils.cp
        static jboolean android_net_utils_runDhcp(JNIEnv* env, jobject clazz, jstring ifname, jobject info)
        {
          return android_net_utils_runDhcpCommon(env, clazz, ifname, info, false);
        }
        static jboolean android_net_utils_runDhcpCommon(JNIEnv* env, jobject clazz, jstring ifname,
        jobject dhcpResults, bool renew)
        {
          if (renew) {
            result = ::dhcp_do_request_renew(nameStr, ipaddr, gateway, &prefixLength,
                dns, server, &lease, vendorInfo, domains, mtu);
          } else {
             result = ::dhcp_do_request(nameStr, ipaddr, gateway, &prefixLength,
                dns, server, &lease, vendorInfo, domains, mtu);
          }
        }
        system/core/libnetutils/dhcp_utils.c
        见博文：《Android系统DHCP问题》
        上处DHCP Client和DHCP server（system/bin/dhcpd进程）通过property_get/set 共享内存来共享信息
        */
        Log.e(TAG, "DHCP request error:" + NetworkUtils.getDhcpError());
        // set our score lower than any network could go
        // so we get dropped.
        mFactory.setScoreFilter(-1);
        return;
      }
      mNetworkAgent = new NetworkAgent(mFactory.getLooper(), mContext,
                            NETWORK_TYPE, mNetworkInfo, mNetworkCapabilities, mLinkProperties,
                            NETWORK_SCORE)
    }
  });
  dhcpThread.start();
}

三、项目问题

应用程序调用关键API

public void updateDevInfo(EthernetDevInfo info);

配置完成以后ConnectivityService向EthernetManager发送CONNECTIVITY_ACTION_IMMEDIATE的广播；EthernetManager接收到该广播以后向应用程序发送ETHERNET_INTERFACE_CONF_CHANGED广播。否则；应用程序将TIMEOUT。

    public static final String EXTRA_ETHERNET_STATE = "ETHERNET_state";
    public static final String ETHERNET_INTERFACE_CONF_CHANGED =
                                "android.net.ethernet.ETHERNET_INTERFACE_CONF_CHANGED"; //add by tank
    private void sendEthBroadcast(String action, boolean state) {  
      String bootStr = SystemProperties.get("sys.boot_completed");
      Log.d(TAG, "sendEthBroadcast -->: " + bootStr);
      if(bootStr.equals("1")) { //boot complete
        Intent intent = new Intent(action);
        intent.putExtra(EXTRA_ETHERNET_STATE, state);

        Log.d(TAG, "sendEthBroadcast --> action= " + action + " state=" + state);
        mContext.sendBroadcast(intent);
      }
    }
    //连接成功调用如下：
    sendEthBroadcast(ETHERNET_INTERFACE_CONF_CHANGED, true);
    //连接失败调用如下：
    sendEthBroadcast(ETHERNET_INTERFACE_CONF_CHANGED, false);

1.手动配置IP后子网掩码错误，以及子网掩码在应用不显示问题

原因：向上层应用提供信息有误

2.手动配置IP提示网关错误，以及网关获取错误问题

原因：同上

3.自动获取IP地址速度慢

原因：应用程序在等待ConnectivityService的广播通过EthernetManager发送的广播