设置项网络按钮类定义
网络监听二:statusbar frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/NetworkController.java
EthernetStateMachine.java -> 网络状态机,用于管理网络状态变化及动作逻辑 EthernetManager.java -> 网络管理器,是app和EthernetService信息交互的桥梁 EthernetInfo.java -> 网络状态参数类,是Parcelable的一个实现 EthernetInfo.aidl -> aidl文件,Manager和service统一使用的数据结构 IEthernetManager.aidl -> aidl文件,用于Manager和service通信
private class InterfaceStateReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { if (intent.getAction().equals(EthernetManager.INTERFACE_STATE_CHANGED_ACTION)) { ... Intent newIntent = new Intent(EthernetManager.NETWORK_STATE_CHANGED_ACTION); newIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT); newIntent.putExtra(EthernetManager.EXTRA_ETHERNET_INFO, ei);在service中,可以看到发送NETWORK_STATE_CHANGED_ACTION的发送动作,而这个发送行为还不是底层上报的状态直接启动的,而是上面说的网络状态机,它发送的INTERFACE_STATE_CHANGED_ACTION广播信息,怎么源头又跑上面去了?有些人可能并不理解为什么在framework里面要把一个简单的事件广播要这么来回的发送,等明白了网络状态机的作用,就知道这些过程的逻辑性了。
addState(mRootState); addState(mIdleState, mRootState); //addState(mObtainingLinkState, mRootState); addState(mObtainingIpState, mRootState); addState(mIPConnectedState, mRootState); addState(mDisconnectingState, mRootState);
private void sendInterfaceStateChangedBroadcast() { if (DBG) Slog.d(TAG, Sending INTERFACE_STATE_CHANGED_ACTION for + mEthernetInfo.getName()); Intent intent = new Intent(EthernetManager.INTERFACE_STATE_CHANGED_ACTION); intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT); intent.putExtra(EthernetManager.EXTRA_ETHERNET_INFO, new EthernetInfo(mEthernetInfo)); mContext.sendBroadcast(intent); } private void setNetworkDetailedState(DetailedState state) { if (DBG) Slog.d(TAG, mEthernetInfo.getName() + setDetailed state, old = + mEthernetInfo.getDetailedState() + and new state= + state); if (state != mEthernetInfo.getDetailedState()) { mEthernetInfo.setDetailedState(state, null, null); mEthernetInfo.setIsAvailable(true); sendInterfaceStateChangedBroadcast(); } } void dhcpSuccess(DhcpResults dr) { if (DBG) Slog.d(TAG, mEthernetInfo.getName() + DHCP successful); LinkProperties lp = dr.linkProperties; ... setNetworkDetailedState(DetailedState.CONNECTED); }
public void updateInterface(EthernetInfo newInfo) { if (newInfo == null) { Slog.e(TAG, Null EthernetInfo); return; } if (mAvailableInterface == null) { Slog.e(TAG, Unable to find statemachine for interface + newInfo.getName()); return; } sendMessage(mAvailableInterface, EthernetStateMachine.CMD_UPDATE_INTERFACE, newInfo); if(DBG) Slog.d(TAG, newInfo.getName() + updateInterface done); }看到了来来回回的广播,至此算是结束了,这里还要注意一点,广播收发程序中,我们要注意一个序列化参数的传递,就是EthernetInfo对象,这个对象存储着当前网络状态参数。
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); }看下NetworkManagementEventObserver的实现:
private class NetworkManagementEventObserver extends INetworkManagementEventObserver.Stub { public void interfaceAdded(String iface) { if(DBG) Slog.d(TAG, interfaceAdded: + iface); addInterface(iface); } public void interfaceRemoved(String iface) { if(DBG) Slog.d(TAG, interfaceRemoved: + iface); removeInterface(iface); } public void limitReached(String limitName, String iface) {} public void interfaceClassDataActivityChanged(String label, boolean active) {} public void interfaceLinkStateChanged(String iface, boolean up) { if(DBG) Slog.d(TAG, interfaceLinkStateChanged for + iface + , up = + up); if (mAvailableInterface != null && up) { //sendMessage(mAvailableInterface, //EthernetStateMachine.CMD_LINK_UP); } } public void interfaceStatusChanged(String iface, boolean up) { if(DBG) Slog.d(TAG, interfaceStatusChanged for + iface + , up = + up); //addInterface(iface); } public void addressUpdated(String address, String iface, int flags, int scope) {} public void addressRemoved(String address, String iface, int flags, int scope) {} }这里我们看到seivice从NetworkManagementService进行函数回调。 NetworkManagementService也是注册到系统中的服务项,顾名思义负责网络管理服务,具体功能在本篇不做深入分析,其中之一通过socket和netd进行交互,这个在后面继续跟踪。
SystemServer.java try { Slog.i(TAG, NetworkManagement Service); networkManagement = NetworkManagementService.create(context); ServiceManager.addService(Context.NETWORKMANAGEMENT_SERVICE, networkManagement); } catch (Throwable e) { reportWtf(starting NetworkManagement Service, e); }在后续的分析中,我们开始了解到framework到native的交互,这里我们先看一张网络的图示
private static final String NETD_SOCKET_NAME = netd; private NetworkManagementService(Context context, String socket) { mContext = context; if (simulator.equals(SystemProperties.get(ro.product.device))) { return; } mConnector = new NativeDaemonConnector( new NetdCallbackReceiver(), socket, 10, NETD_TAG, 160); mThread = new Thread(mConnector, NETD_TAG); // Add ourself to the Watchdog monitors. Watchdog.getInstance().addMonitor(this); }这里socket值就是netd字符串,service启动了名为NativeDaemonConnector的Runnable线程,同时从构造函数中传递了NetdCallbackReceiver 对象,用于回调处理各种网络事件。
private class NetdCallbackReceiver implements INativeDaemonConnectorCallbacks { @Override public void onDaemonConnected() { @Override public boolean onEvent(int code, String raw, String[] cooked) { switch (code) { case NetdResponseCode.InterfaceChange: } else if (cooked[2].equals(linkstate) && cooked.length == 5) { // 网络状态变化事件在这里回调处理 notifyInterfaceLinkStateChanged(cooked[3], cooked[4].equals(up)); return true; }
/** * Notify our observers of an interface link state change * (typically, an Ethernet cable has been plugged-in or unplugged). */ private void notifyInterfaceLinkStateChanged(String iface, boolean up) { final int length = mObservers.beginBroadcast(); for (int i = 0; i < length; i++) { try { mObservers.getBroadcastItem(i).interfaceLinkStateChanged(iface, up); } catch (RemoteException e) { } catch (RuntimeException e) { } } mObservers.finishBroadcast(); }上面说了NativeDaemonConnector是一个Runnable的实现,那么这个线程在后台做些什么工作呢?在线程run函数中可以看到线程在while死循环中一直listenToSocket,可以猜想这里是在监听获取native中网络相关事件的地方了。
@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); } }我们接下来看一下LocalSocket相关的类,了解一下这个socket是如何connect和get的。 LocalSocket*相关的类定义在 frameworks/base/core/java/android/net/ |->LocalSocket.java
static const RegJNIRec gRegJNI[] = { REG_JNI(register_android_net_LocalSocketImpl),了解了库加载的问题后,我们接着看LocalSocketImpl.java中使用的几个重要的函数:
connect() getInputStream() getOutputStream()函数具体内容不具体贴出来,其中可以看到调用了本地方法如read_native(),writeba_native()等。我们就走到native的大门了。打开本地函数文件,看下native中本地函数列表。 frameworks/base/core/jni/android_net_LocalSocketImpl.cpp
static JNINativeMethod gMethods[] = { /* name, signature, funcPtr */ {getOption_native, (Ljava/io/FileDescriptor;I)I, (void*)socket_getOption}, {setOption_native, (Ljava/io/FileDescriptor;III)V, (void*)socket_setOption}, {connectLocal, (Ljava/io/FileDescriptor;Ljava/lang/String;I)V, (void*)socket_connect_local}, {bindLocal, (Ljava/io/FileDescriptor;Ljava/lang/String;I)V, (void*)socket_bind_local}, {listen_native, (Ljava/io/FileDescriptor;I)V, (void*)socket_listen}, {accept, (Ljava/io/FileDescriptor;Landroid/net/LocalSocketImpl;)Ljava/io/FileDescriptor;, (void*)socket_accept}, {shutdown, (Ljava/io/FileDescriptor;Z)V, (void*)socket_shutdown}, {available_native, (Ljava/io/FileDescriptor;)I, (void*) socket_available}, {pending_native, (Ljava/io/FileDescriptor;)I, (void*) socket_pending}, {read_native, (Ljava/io/FileDescriptor;)I, (void*) socket_read}, {readba_native, ([BIILjava/io/FileDescriptor;)I, (void*) socket_readba}, {writeba_native, ([BIILjava/io/FileDescriptor;)V, (void*) socket_writeba}, {write_native, (ILjava/io/FileDescriptor;)V, (void*) socket_write}, {getPeerCredentials_native, (Ljava/io/FileDescriptor;)Landroid/net/Credentials;, (void*) socket_get_peer_credentials} //,{getSockName_native, (Ljava/io/FileDescriptor;)Ljava/lang/String;, // (void *) socket_getSockName} }; int register_android_net_LocalSocketImpl(JNIEnv *env){}