Android Ethernet从上至下解析一

            addState(mRootState);
            addState(mIdleState, mRootState);
            //addState(mObtainingLinkState, mRootState);
            addState(mObtainingIpState, mRootState);
            addState(mIPConnectedState, mRootState);
            addState(mDisconnectingState, mRootState);

    public EthernetService(Context context) {
        mContext = context;
        mNetd = INetworkManagementService.Stub.asInterface(
                ServiceManager.getService(Context.NETWORKMANAGEMENT_SERVICE)
        );

        try {
            mNetd.registerObserver(new NetworkManagementEventObserver());
        } catch (RemoteException e) {
            Slog.e(TAG, "Remote NetworkManagementService error: " + e);
        }

    @Override
    public void run() {
        mCallbackHandler = new Handler(FgThread.get().getLooper(), this);

        while (true) {
            try {
                listenToSocket();
            } catch (Exception e) {
                loge("Error in NativeDaemonConnector: " + e);
                SystemClock.sleep(5000);
            }
        }
    }
    private void listenToSocket() throws IOException {
        LocalSocket socket = null;

        try {
            // 创建一个socket
            socket = new LocalSocket();
            LocalSocketAddress address = determineSocketAddress();
            socket.connect(address);
            // 从socket中获取流数据并处理
            InputStream inputStream = socket.getInputStream();
            synchronized (mDaemonLock) {
                mOutputStream = socket.getOutputStream();
            }
            ...
                mCallbackHandler.sendMessage(mCallbackHandler.obtainMessage(
                                        event.getCode(), event.getRawEvent()));
    // 收到流数据时，直接发给主线程，通过NetdCallbackReceiver 对象进行回调处理
    @Override
    public boolean handleMessage(Message msg) {
        String event = (String) msg.obj;
        try {
            if (!mCallbacks.onEvent(msg.what, event, NativeDaemonEvent.unescapeArgs(event))) {
                log(String.format("Unhandled event '%s'", event));
            }
        } catch (Exception e) {
            loge("Error handling '" + event + "': " + e);
        }
        return true;
    }
    
    private LocalSocketAddress determineSocketAddress() {
        // If we're testing, set up a socket in a namespace that's accessible to test code.
        // In order to ensure that unprivileged apps aren't able to impersonate native daemons on
        // production devices, even if said native daemons ill-advisedly pick a socket name that
        // starts with __test__, only allow this on debug builds.
        if (mSocket.startsWith("__test__") && Build.IS_DEBUGGABLE) {
            return new LocalSocketAddress(mSocket);
        } else {
            return new LocalSocketAddress(mSocket, LocalSocketAddress.Namespace.RESERVED);
        }
    }