📌一、系统启动阶段:WiFi 服务在 system_server 进程中
的初始化
android/frameworks/base/services/java/com/android/server/SystemServer.java中,系统会检查设备是否支持 WiFi 功能(通过PackageManager.FEATURE_WIFI判断)。若支持,则通过mSystemServiceManager.startServiceFromJar启动两个核心服务:
WifiService(主服务,负责 WiFi 核心功能调度)WifiScanningService(扫描服务,专门处理 WiFi 扫描逻辑)
代码片段如下:
private static final String WIFI_SERVICE_CLASS =
"com.android.server.wifi.WifiService";
if (context.getPackageManager().hasSystemFeature(
PackageManager.FEATURE_WIFI)) {
// 优先启动WiFi主服务,为依赖组件提供基础
t.traceBegin("StartWifi");
mSystemServiceManager.startServiceFromJar(
WIFI_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();
// 启动扫描服务,处理WiFi扫描相关任务
t.traceBegin("StartWifiScanning");
mSystemServiceManager.startServiceFromJar(
WIFI_SCANNING_SERVICE_CLASS, WIFI_APEX_SERVICE_JAR_PATH);
t.traceEnd();
}
📌二、服务注册机制:将 WiFi 服务暴露给系统
WifiService启动后,需通过publishBinderService方法注册到ServiceManager,使其他组件可通过 Binder 机制调用其功能。该方法定义于android/frameworks/base/services/core/java/com/android/server/SystemService.java:
/**
* 发布服务,使其可被其他服务和应用访问
* @param name 服务名称(如WiFi服务对应Context.WIFI_SERVICE)
* @param service Binder服务实例(此处为WifiServiceImpl)
* @param allowIsolated 是否允许隔离进程访问
* @param dumpPriority 支持的dump优先级掩码
*/
protected final void publishBinderService(String name, IBinder service,
boolean allowIsolated, int dumpPriority) {
ServiceManager.addService(name, service, allowIsolated, dumpPriority);
}
📌三、WifiService 与 WifiServiceImpl 的职责划分
WifiService是系统服务入口,而WifiServiceImpl是实际业务逻辑的执行者,二者通过组合模式协作:
- WifiService 的初始化
android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiService.java
public WifiService(Context contextBase) {
super(contextBase);
mWifiContext = new WifiContext(contextBase); // 创建WiFi专用上下文
WifiInjector injector = new WifiInjector(mWifiContext); // 依赖注入器,管理WiFi组件
WifiAsyncChannel channel = new WifiAsyncChannel(TAG); // 异步通信通道
// 初始化核心实现类WifiServiceImpl
mImpl = new WifiServiceImpl(mWifiContext, injector, channel);
}
- 服务注册触发:
WifiService在onStart阶段调用publishBinderService,将WifiServiceImpl实例注册到系统:
@Override
public void onStart() {
Log.i(TAG, "Registering " + Context.WIFI_SERVICE);
publishBinderService(Context.WIFI_SERVICE, mImpl); // 注册核心实现类
}
核心区别:
WifiService:系统服务的 “壳”,负责启动流程和服务注册,不处理具体业务。WifiServiceImpl:WiFi 服务的 “大脑”,接收并处理所有应用层请求(如开关 WiFi、扫描、连接网络等)。
📌四、WifiServiceImpl 的初始化与核心依赖
WifiServiceImpl在构造时通过WifiInjector获取关键组件,奠定 WiFi 功能基础android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiServiceImpl.java
public WifiServiceImpl(Context context, WifiInjector wifiInjector, AsyncChannel asyncChannel) {
mContext = context;
mWifiInjector = wifiInjector; // 依赖注入器,提供组件实例
...
// 客户端模式管理器:负责STA(Station)模式下的连接管理
mClientModeImpl = mWifiInjector.getClientModeImpl();
// 活跃模式控制器:管理WiFi的多种工作模式(如STA、AP、P2P等)
mActiveModeWarden = mWifiInjector.getActiveModeWarden();
...
}
关键组件作用:
WifiInjector:依赖注入工具,统一管理 WiFi 模块的对象创建和依赖关系,降低组件耦合。WifiAsyncChannel:异步通信工具,用于跨进程 / 线程的消息传递(如与 WiFi 芯片驱动交互)。ClientModeImpl:处理 STA 模式(设备作为客户端连接其他 WiFi)的核心逻辑。ActiveModeWarden:协调 WiFi 的多种工作模式(如同时开启 STA 和热点时的资源分配)。
📌五、点击 WiFi 开关后的事件流转(从 UI 到服务层)
当用户在设置界面点击 WiFi 开关,系统通过 WifiManager.setWifiEnabled(boolean) 接口触发 WiFi 状态变更。该调用通过 AIDL 机制传递至 WifiServiceImpl,并在其中完成权限校验与状态切换:
android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiServiceImpl.java
@Override
public synchronized boolean setWifiEnabled(String packageName, boolean enable) {
// 权限校验:是否具备修改 WiFi 状态的权限
if (enforceChangePermission(packageName) != MODE_ALLOWED) return false;
boolean isPrivileged = isPrivileged(Binder.getCallingPid(), Binder.getCallingUid());
// 非特权应用的限制条件
if (!isPrivileged && !isDeviceOrProfileOwner(...) && !mWifiPermissionsUtil.isTargetSdkLessThan(...) && !isSystem(...)) {
mLog.info("setWifiEnabled not allowed for uid=%").c(Binder.getCallingUid()).flush();
return false;
}
// 飞行模式下限制 WiFi 开关
if (mSettingsStore.isAirplaneModeOn() && !isPrivileged) {
mLog.err("setWifiEnabled in Airplane mode: only Settings can toggle wifi").flush();
return false;
}
// 热点开启时限制 WiFi 开关
if (!isPrivileged && mTetheredSoftApTracker.getState() == WIFI_AP_STATE_ENABLED) {
mLog.err("setWifiEnabled with SoftAp enabled: only Settings can toggle wifi").flush();
return false;
}
// 日志记录与状态处理
mLog.info("setWifiEnabled package=% uid=% enable=%").c(packageName).c(Binder.getCallingUid()).c(enable).flush();
long ident = Binder.clearCallingIdentity();
try {
if (!mSettingsStore.handleWifiToggled(enable)) return true;
} finally {
Binder.restoreCallingIdentity(ident);
}
// 记录用户行为指标
if (mWifiPermissionsUtil.checkNetworkSettingsPermission(Binder.getCallingUid())) {
if (enable) {
mWifiMetrics.logUserActionEvent(UserActionEvent.EVENT_TOGGLE_WIFI_ON);
} else {
WifiInfo wifiInfo = mClientModeImpl.syncRequestConnectionInfo();
mWifiMetrics.logUserActionEvent(UserActionEvent.EVENT_TOGGLE_WIFI_OFF,
wifiInfo == null ? -1 : wifiInfo.getNetworkId());
}
}
mWifiMetrics.incrementNumWifiToggles(isPrivileged, enable);
// 通知状态机:WiFi 开关已触发
mActiveModeWarden.wifiToggled();
return true;
}
小结:
- 权限控制非常严格,确保只有系统级或特权应用能在特定状态下切换 WiFi。
- 状态变更最终通过
ActiveModeWarden.wifiToggled()进入 WiFi 状态机流程。
📌六、ActiveModeWarden 与 WiFi 状态机的联动机制
ActiveModeWarden 是 WiFi 模式调度的核心组件,负责协调 STA(客户端)、SoftAP(热点)、P2P 等模式的切换。其 wifiToggled() 方法是 WiFi 状态变更的入口:
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ActiveModeWarden.java
public void wifiToggled() {
mWifiController.sendMessage(WifiController.CMD_WIFI_TOGGLED);
}
- 状态机初始化流程
WifiServiceImpl有下面三个状态:

在WifiServiceImpl启动阶段,ActiveModeWarden.start()会根据当前设置初始化状态机:
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ActiveModeWarden.java
public void start() {
if (shouldEnableSta()) {
startClientModeManager();
setInitialState(mEnabledState);
} else {
setInitialState(mDisabledState);
}
}
private boolean shouldEnableSta() {
return mSettingsStore.isWifiToggleEnabled() || checkScanOnlyModeAvailable();
}
- 若 WiFi 开关为开启或允许扫描模式,则进入
mEnabledState。 - 否则进入
mDisabledState,等待用户触发。
- CMD_WIFI_TOGGLED 消息处理逻辑
当状态机处于mDisabledState且收到CMD_WIFI_TOGGLED消息时,会尝试启动 STA 模式:
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ActiveModeWarden.java
case CMD_WIFI_TOGGLED:
if (shouldEnableSta()) {
startClientModeManager();
transitionTo(mEnabledState);
}
break;
- 启动 ClientModeManager
startClientModeManager()方法创建并启动 STA 模式管理器:
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ActiveModeWarden.java
private boolean startClientModeManager() {
ClientListener listener = new ClientListener();
ClientModeManager manager = mWifiInjector.makeClientModeManager(listener);
listener.setActiveModeManager(manager);
manager.start();
if (!switchClientModeManagerRole(manager)) return false;
mActiveModeManagers.add(manager);
return true;
}
组件说明:
ClientModeManager:负责 STA 模式的生命周期管理。ClientListener:监听器,用于接收状态变更回调。switchClientModeManagerRole():切换角色(如主连接 vs 辅助连接)。
📌七、WifiController 状态机响应 WiFi 开关事件
当 ActiveModeWarden 决定启动 STA(Station)模式后,会执行 startClientModeManager(),核心动作是创建 ClientModeManager 实例,并开始切换到对应角色(如 ROLE_CLIENT_PRIMARY 或 ROLE_CLIENT_SCAN_ONLY)。
- ClientModeManager 创建时,初始化自己的内部状态机
在构造函数中会创建一个 ClientModeStateMachine,用于管理 WiFi 客户端模式的生命周期
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java
ClientModeManager(...) {
...
mStateMachine = new ClientModeStateMachine(looper);
mDeferStopHandler = new DeferStopHandler(TAG, looper);
...
}
- start() → 设置默认角色为 “扫描模式” + 启动状态机
ClientModeManager 的start()方法会先设置目标模式为扫描-only,然后把CMD_START发送到状态机
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java
public void start() {
mTargetRole = ROLE_CLIENT_SCAN_ONLY; // 默认只是扫描模式
mStateMachine.sendMessage(ClientModeStateMachine.CMD_START);
}
此时,仅启动了状态机,还没有真正进入“连接热点”的模式。
- ClientModeStateMachine 的状态结构 & 初始状态
ClientModeStateMachine 内部定义了 4 个状态:

//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java
ClientModeStateMachine(Looper looper) {
addState(mIdleState);
addState(mStartedState);
addState(mScanOnlyModeState, mStartedState);
addState(mConnectModeState, mStartedState);
setInitialState(mIdleState);
start(); // 启动状态机
}
状态解释
mIdleState:WiFi 功能未启动mStartedState:已进入 Client 模式,但不确定是 Scan-only 还是 ConnectmScanOnlyModeState:仅用于扫描,不允许连接 APmConnectModeState:设备可以开始连接 WiFi AP(真正 STA 模式)
- ActiveModeWarden 调用 switchClientModeManagerRole() 触发角色切换
当 WiFi 开关打开时,ActiveModeWarden会判断是扫描-only还是真正连接模式,并调用setRole()推动状态机切换角色
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ActiveModeWarden.java
private boolean switchClientModeManagerRole(ClientModeManager modeManager) {
if (mSettingsStore.isWifiToggleEnabled()) {
modeManager.setRole(ROLE_CLIENT_PRIMARY); // 打开 WiFi → STA 模式
} else if (checkScanOnlyModeAvailable()) {
modeManager.setRole(ROLE_CLIENT_SCAN_ONLY);
}
}
- setRole() 发送消息给状态机执行模式切换
//android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java
public void setRole(@Role int role) {
Preconditions.checkState(CLIENT_ROLES.contains(role));
if (role == ROLE_CLIENT_SCAN_ONLY) {
mTargetRole = role;
// Switch client mode manager to scan only mode.
mStateMachine.sendMessage(ClientModeStateMachine.CMD_SWITCH_TO_SCAN_ONLY_MODE);
} else if (CLIENT_CONNECTIVITY_ROLES.contains(role)) {
mTargetRole = role;
// Switch client mode manager to connect mode.
mStateMachine.sendMessage(ClientModeStateMachine.CMD_SWITCH_TO_CONNECT_MODE, role);
}
}
当收到 CMD_SWITCH_TO_CONNECT_MODE 时,状态机会从 ScanOnlyMode 或 Idle 切入 ConnectModeState,真正启动 STA 连接流程。
- 小结
ActiveModeWarden 负责“决定模式”,ClientModeManager 负责“执行模式”,ClientModeStateMachine 负责“把模式跑起来”。
到这里 WiFiController 状态机完成 Disabled → Enabled 状态跳转,WiFiController 在DisabledState处理完CMD_WIFI_TOGGLED后退出,进入EnabledState,系统保持 WiFi 打开,等待连接。
📌八、ClientModeStateMachine 对初始化消息的处理流程
从上流程可知,“ClientModeStateMachine.CMD_START”和“ClientModeStateMachine.CMD_SWITCH_TO_CONNECT_MODE”两条消息还处于待处理状态。
在ClientModeStateMachine类构造函数可知,状态机初始状态为mIdleState,此时,将执行IdleState.enter()方法进入该状态,并开始处理CMD_START消息。
private class IdleState extends State {
... ... ... ...
case CMD_START:
// Always start in scan mode first.
mClientInterfaceName =mWifiNative.setupInterfaceForClientInScanMode(
mWifiNativeInterfaceCallback);
if (TextUtils.isEmpty(mClientInterfaceName)) {
Log.e(TAG, "Failed to create ClientInterface. Sit in Idle");
mModeListener.onStartFailure();
break;
}
transitionTo(mScanOnlyModeState);
break;
... ... ... ...
在处理CMD_START消息时,将调用WifiNative类中setupInterfaceForClientInScanMode()方法。
📌九、WifiNative 接口初始化的核心实现
先看WifiNative类中该方法的实现
android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiNative.java
public String setupInterfaceForClientInScanMode(
@NonNull InterfaceCallback interfaceCallback) {
synchronized (mLock) {
//startwifi 加载WiFi驱动
if (!startHal()) {
Log.e(TAG, "Failed to start Hal");
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToHal();
return null;
}
//分配对应的接口
Iface iface = mIfaceMgr.allocateIface(Iface.IFACE_TYPE_STA_FOR_SCAN);
if (iface == null) {
Log.e(TAG, "Failed to allocate new STA iface");
return null;
}
iface.externalListener = interfaceCallback;
//创建对应的station接口
iface.name = createStaIface(iface);
if (TextUtils.isEmpty(iface.name)) {
Log.e(TAG, "Failed to create iface in vendor HAL");
mIfaceMgr.removeIface(iface.id);
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToHal();
return null;
}
//设置客户端接口
if (!mWifiCondManager.setupInterfaceForClientMode(iface.name, Runnable::run,
new NormalScanEventCallback(iface.name),
new PnoScanEventCallback(iface.name))) {
Log.e(TAG, "Failed to setup iface in wificond=" + iface.name);
teardownInterface(iface.name);
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToWificond();
return null;
}
//设置接口up/down的检测通知
iface.networkObserver = new NetworkObserverInternal(iface.id);
if (!registerNetworkObserver(iface.networkObserver)) {
Log.e(TAG, "Failed to register network observer for iface=" + iface.name);
teardownInterface(iface.name);
return null;
}
//启动wpa_supplicant事件监听
mWifiMonitor.startMonitoring(iface.name);
onInterfaceStateChanged(iface, isInterfaceUp(iface.name));
//获取WiFi支持的feature
iface.featureSet = getSupportedFeatureSetInternal(iface.name);
return iface.name;
}
}
- startHal方法内部调用
startHal()->startHal()->WifiVendorHal.startVendorHal()->HalDeviceManager.start()->HalDeviceManager.startWifi()
这里看下启动WiFi的方法“HalDeviceManager.startWifi()”。在这个方法中,将加载WiFi驱动。
private boolean startWifi() {
... ... ... ...
synchronized (mLock) {
try {
if (mWifi == null) {
return false;
} else {
int triedCount = 0;
//加载WiFi驱动将尝试4次,START_HAL_RETRY_TIMES=3。
while (triedCount <= START_HAL_RETRY_TIMES) {
WifiStatus status = mWifi.start();
if (status.code == WifiStatusCode.SUCCESS) {
initIWifiChipDebugListeners();
managerStatusListenerDispatch();
if (triedCount != 0) {
}
return true;
} else if (status.code == WifiStatusCode.ERROR_NOT_AVAILABLE) {
try {
Thread.sleep(START_HAL_RETRY_INTERVAL_MS);
} catch (InterruptedException ignore) {
// no-op
}
triedCount++;
} else {
// Should not retry on other failures.
Log.e(TAG, "Cannot start IWifi: " + statusString(status));
return false;
}
}
... ... ... ...
在该方法startWifi,mWifi.start()方法是启动实际加载WiFi动作的调用,这里涉及HIDL机制调用。通过获取IWifi接口对象,调用其方法。这里IWifi接口对象是IWifi.hal文件中实现。
android/hardware/interfaces/wifi/1.0/IWifi.hal在编译时,编译器会将IWifi.hal解析为IWifi.java文件,直接看该文件中的start方法实现即可。
android/out/soong//.intermediates/hardware/interfaces/wifi/1.0/android.hardware.wifi-V1.0-java_gen_java/gen/srcs/android/hardware/wifi/V1_0/IWifi.java
public android.hardware.wifi.V1_0.WifiStatus start() throws android.os.RemoteException {
try {
... ... ... ...
mRemote.transact(3 /* start */, _hidl_request, _hidl_reply, 0 /* flags */);
_hidl_reply.verifySuccess();
_hidl_request.releaseTemporaryStorage();
return _hidl_out_status;
} finally {
_hidl_reply.release();
}
}
通过binder调用,将调用到wifi.cpp中的start()方法。
android/hardware/interfaces/wifi/1.4/default/wifi.cpp
Return<void> Wifi::start(start_cb hidl_status_cb) {
return validateAndCall(this, WifiStatusCode::ERROR_UNKNOWN,
&Wifi::startInternal, hidl_status_cb);
}
wifi.cpp->start() ==> wifi.cpp->startInternal() ==> wifi.cpp->initializeModeControllerAndLegacyHal()
==> WifiModeController->initialize() ==> DriverTool->LoadDriver()
通过调用DriverTool->LoadDriver将返回到Android framework中。下面是LoadDriver()的实现。
android/frameworks/opt/net/wifi/libwifi_hal/include/wifi_hal/driver_tool.cpp
bool DriverTool::LoadDriver() {
return ::wifi_load_driver() == 0;
}
在wifi_load_driver()方法中,将调用系统接口加载WiFi驱动ko。关于系统insmod接口的调用,本文不做分析。到这里,已梳理完在WifiNative类中调用的startHal()方法。
android/frameworks/opt/net/wifi/libwifi_hal/wifi_hal_common.cpp
int wifi_load_driver() {
... ... ... ...
insmod(file,args);
... ... ... ...
}
- 调用WifiNl80211Manager类的setupInterfaceForClientMode()方法。
该类的主要对WiFi 80211nl管理接口的封装,接口在WiFicond守护进程中呈现给WiFi框架。该类提供的接口仅使用与WiFi框架,访问权限受selinux权限保护。
setupInterfaceForClientMode()方法主要为Station模式设置接口。
android/frameworks/base/wifi/java/android/net/wifi/nl80211/WifiNl80211Manager.java
public boolean setupInterfaceForClientMode(@NonNull String ifaceName,
@NonNull @CallbackExecutor Executor executor,
@NonNull ScanEventCallback scanCallback, @NonNull ScanEventCallback pnoScanCallback) {
... ... ... ...
// Refresh Handlers
mClientInterfaces.put(ifaceName, clientInterface);
try {
IWifiScannerImpl wificondScanner = clientInterface.getWifiScannerImpl();
mWificondScanners.put(ifaceName, wificondScanner);
Binder.allowBlocking(wificondScanner.asBinder());
ScanEventHandler scanEventHandler = new ScanEventHandler(executor, scanCallback);
mScanEventHandlers.put(ifaceName, scanEventHandler);
wificondScanner.subscribeScanEvents(scanEventHandler);
PnoScanEventHandler pnoScanEventHandler = new PnoScanEventHandler(executor,
pnoScanCallback);
mPnoScanEventHandlers.put(ifaceName, pnoScanEventHandler);
wificondScanner.subscribePnoScanEvents(pnoScanEventHandler);
... ... ... ...
}
到这里,ClientModeStateMachine状态机在IdleState状态成功处理完了CMD_START消息。状态机将转到“mScanOnlyModeState”状态,将会执行以下调用流程(具体原因可查看状态机机制)。
IdleState.exit()->StartedState.enter()->StartedState.exit()->ScanOnlyModeState.enter()。
在状态转时,在StartedState.exit()中,将调用setOperationalMode方法。
public void exit() {
mClientModeImpl.setOperationalMode(ClientModeImpl.DISABLED_MODE, null);
}
📌十、ClientModeImpl 的状态机与模式管理
这里将触及开篇提到的ClientModeImpl类。首先看下其构造函数,除了其他对象赋值初始化外,又一个状态机将与我们见面。

android/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeImpl.java
public ClientModeImpl(.......){
super(TAG, looper);
... ... .... ....
// CHECKSTYLE:OFF IndentationCheck
addState(mDefaultState);
addState(mConnectModeState, mDefaultState);
addState(mL2ConnectedState, mConnectModeState);
addState(mObtainingIpState, mL2ConnectedState);
addState(mConnectedState, mL2ConnectedState);
addState(mRoamingState, mL2ConnectedState);
addState(mDisconnectingState, mConnectModeState);
addState(mDisconnectedState, mConnectModeState);
// CHECKSTYLE:ON IndentationCheck
setInitialState(mDefaultState);
... ... .... ....
}
public void setOperationalMode(int mode, String ifaceName) {
... ... ...
//打开WiFi mode=2,因此状态机进入到mDefaultState状态
if (mode != CONNECT_MODE) {
// we are disabling client mode... need to exit connect mode now
transitionTo(mDefaultState);
} else {
... ... ... ...
}
}
📌十一、切换到连接模式的完整流程
目前,还遗留一个消息“ClientModeStateMachine.CMD_SWITCH_TO_CONNECT_MODE”待处理。此时,轮到该消息要被处理了。
ClientModeStateMachine状态机已处于“ScanOnlyModeState”状态,接收到该消息后,在processMessage方法中并未处理,而抛给父状态“StartedState”处理。在StartedState.processMessage()方法中对该消息进行了处理。
public boolean processMessage(Message message) {
... ... ... ...
case CMD_SWITCH_TO_CONNECT_MODE:
mRole = message.arg1; // could be any one of possible connect mode roles.
//更新WiFi打开状态,发送系统广播通知。
updateConnectModeState(WifiManager.WIFI_STATE_ENABLING,
WifiManager.WIFI_STATE_DISABLED);
//切换设置clinent接口到连接模式。
if (!mWifiNative.switchClientInterfaceToConnectivityMode(
mClientInterfaceName)) {
... ... ... ...
mModeListener.onStartFailure();
break;
}
... ... ... ...
transitionTo(mConnectModeState);
break;
}
WifiNative类中,mWifiNative.switchClientInterfaceToConnectivityMode()方法
public boolean switchClientInterfaceToConnectivityMode(@NonNull String ifaceName) {
synchronized (mLock) {
... ... ... ...
//获取设置的接口
final Iface iface = mIfaceMgr.getIface(ifaceName);
if (iface == null) {
return false;
}
if (iface.type == Iface.IFACE_TYPE_STA_FOR_CONNECTIVITY) {
return true;
}
//调用启动wpa_supplicant服务进程
if (!startSupplicant()) {
teardownInterface(iface.name);
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToSupplicant();
return false;
}
//注册设置接口
if (!mSupplicantStaIfaceHal.setupIface(iface.name)) {
return false;
}
iface.type = Iface.IFACE_TYPE_STA_FOR_CONNECTIVITY;
iface.featureSet = getSupportedFeatureSetInternal(iface.name);
... ... ... ...
return true;
}
}
WifiNative.startSupplicant()->WifiNative.startAndWaitForSupplicantConnection()->
SupplicantStaIfaceHal.startDaemon()->SupplicantStaIfaceHal.startDaemon_V1_1()->
SupplicantStaIfaceHal.getSupplicantMockableV1_1()->
SupplicantStaIfaceHal.getSupplicantMockable()
这里看下getSupplicantMockable()方法,将在getService的时候启动wpa_supplicant进程。
通过HIDL调用获取wpa_supplicant服务。ISupplicant.getService(supplicantName)调用到ISupplicant.java。
protected ISupplicant getSupplicantMockable() throws RemoteException, NoSuchElementException {
synchronized (mLock) {
ISupplicant iSupplicant = ISupplicant.getService(supplicantName);
if (iSupplicant == null) {
throw new NoSuchElementException("Cannot get root service.");
}
return iSupplicant;
}
}
android/out/soong/intermediates/hardware/interfaces/wifi/supplicant/1.0/android.hardware.wifi.supplicant-V1.0-java_gen_java/gen/srcs/android/hardware/wifi/supplicant/V1_0/ISupplicant.java
public static ISupplicant getService(String serviceName) throws android.os.RemoteException {
return ISupplicant.asInterface(android.os.HwBinder.getService("android.hardware.wifi.supplicant@1.0::ISupplicant", serviceName));
}
在这个方法中将触发启动wpa_supplicant进程,这里需要注意,在manifest.xml中对其需要进行配置,运行时会将服务名称注册到hwservicemanager中。
wpa_supplicant目录下文件调用:
main.c ==> wpa_supplicant.c->wpa_supplicant_init() ==> notify.c->wpas_notify_supplicant_initialized() ==> hidl.cpp->wpas_hidl_init() ==> Hidl_manager.cpp->registerHidlService()
int HidlManager::registerHidlService(struct wpa_global *global)
{
// Create the main hidl service object and register it.
supplicant_object_ = new Supplicant(global);
if (supplicant_object_->registerAsService("wpa_supplicant") != android::NO_ERROR) {
return 1;
}
return 0;
}
📁附言
概念
- Android WLAN 架构

- AP、STA
- AP(Access Point)模式:热点,发送WiFi
- STA(Station)模式:连接WiFi的客户端
- mac80211、cfg80211和nl80211
- mac80211:是一个Linux内核子系统,是驱动开发者可用于为SoftMAC无线设备写驱动的框架。mac80211在内核空间实现STA模式,在用户空间实现AP模式(hostapd)。
- cfg80211:用于对无线设备进行配置管理,与FullMAC,mac80211和nl80211一起工作。
- nl80211:用于对无线设备进行配置管理,它是一个基本Netlink的用户态协议。