Android Wifi work station Framework and Architecture

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Android Wifi work station Framework and Architecture

with wpa_supplicant 0.8.X, BCM4329.

转载请注明出处。

Settings/Wifi UI part structure

WifiSettings是主对话框

167

168 @Override

169 public void onActivityCreated(Bundle savedInstanceState) {

170 // We don't call super.onActivityCreated() here, since it assumes we already set up

171 // Preference (probably in onCreate()), while WifiSettings exceptionally set it up in

172 // this method.

173

174 mWifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);

175 mWifiManager.asyncConnect(getActivity(), new WifiServiceHandler());

176 if (savedInstanceState != null

177 && savedInstanceState.containsKey(SAVE_DIALOG_ACCESS_POINT_STATE)) {

178 mDlgEdit = savedInstanceState.getBoolean(SAVE_DIALOG_EDIT_MODE);

179 mAccessPointSavedState = savedInstanceState.getBundle(SAVE_DIALOG_ACCESS_POINT_STATE);

180 }

1101 public void asyncConnect(Context srcContext, Handler srcHandler) {

1102 mAsyncChannel.connect(srcContext, srcHandler, getMessenger());

1103 }

establish a half connect between WifiManager and WifiService.

1117 public void connectNetwork(WifiConfiguration config) {

1118 if (config == null) {

1119 return;

1120 }

1121 mAsyncChannel.sendMessage(CMD_CONNECT_NETWORK, config);

1122 }

Activity创建的时候会建立和WifiService的AsyncChannel的连接，WifiService同样会建立一个AsyncChannelHandler来处理来自这个Channel的命令消息。AsyncChannel的所谓异步主要用来传递比较耗时的操作并把结果返回给原请求者。AsyncChannel两端分别有一个MessageHandler，srcHandler请求destHandler，destHandler把结果发回给srcHandler，主要是用于处理比较耗时的操作且在WifiManager中处理返回结果。

严格来说，在WifiService的Interface方法之外再做出一个通道提供额外的方法并不是一个什么好的设计。命令是可以通过同步接口发送给WifiService的，但是WifiService的处理结果如果通过broadcast或intent给WifiManager，则又解耦的过度；如果WifiManager实现一个binder做event sink，又有点小题大做，所以这儿引入这么个AsyncChannel实在是不得以而为之。

WifiSettings界面使能Wifi时会使用定时器请求扫描，获取扫描结果，列出AP列表。Scanner使用定时器，周期性向WifiService请求主动扫描，定时原理是发出本次扫描请求后延迟1s发送下次请求。相关代码如下：

private class Scanner extends Handler {

private int mRetry = 0;

void resume() {

if (!hasMessages(0)) {

sendEmptyMessage(0);

}

void forceScan() {

removeMessages(0);

sendEmptyMessage(0);

}

void pause() {

mRetry = 0;

removeMessages(0);

}

@Override

public void handleMessage(Message message) {

if (mWifiManager.startScanActive()) {

mRetry = 0;

} else if (++mRetry >= 3) {

mRetry = 0;

Toast.makeText(getActivity(), R.string.wifi_fail_to_scan,

Toast.LENGTH_LONG).show();

return;

}

sendEmptyMessageDelayed(0, WIFI_RESCAN_INTERVAL_MS);

}

列出AP列表的代码如下：

In WifiSettings.java

final List<ScanResult> results = mWifiManager.getScanResults(); //同步操作

if (results != null) {

for (ScanResult result : results) {

// Ignore hidden and ad-hoc networks.

if (result.SSID == null || result.SSID.length() == 0 || result.capabilities.contains("[IBSS]")) {

continue;

}

boolean found = false;

for (AccessPoint accessPoint : apMap.getAll(result.SSID)) {

if (accessPoint.update(result))

found = true;

}

if (!found) {

AccessPoint accessPoint = new AccessPoint(getActivity(), result);

accessPoints.add(accessPoint);

apMap.put(accessPoint.ssid, accessPoint);

}

private void updateAccessPoints() {

final int wifiState = mWifiManager.getWifiState();

switch (wifiState) {

case WifiManager.WIFI_STATE_ENABLED:

// AccessPoints are automatically sorted with TreeSet.

final Collection<AccessPoint> accessPoints = constructAccessPoints();

getPreferenceScreen().removeAll();

if (mInXlSetupWizard) {

((WifiSettingsForSetupWizardXL)getActivity()).onAccessPointsUpdated(

getPreferenceScreen(), accessPoints);

} else {

for (AccessPoint accessPoint : accessPoints) {

// When WAPI is not customized to be on all

// WAPI APs will be invisible

if (accessPoint.isVisible()) {

getPreferenceScreen().addPreference(accessPoint);

}

break;

case WifiManager.WIFI_STATE_ENABLING:

getPreferenceScreen().removeAll();

break;

case WifiManager.WIFI_STATE_DISABLING:

addMessagePreference(R.string.wifi_stopping);

break;

case WifiManager.WIFI_STATE_DISABLED:

addMessagePreference(R.string.wifi_empty_list_wifi_off);

break;

}

可以看出对ADHOC的AP，隐藏AP（无SSID的）做了过滤处理。

当在AP列表上，长按某个AP时弹出三菜单Menu - ContextMenu。

这个Menu主要是连接该AP，修改该AP，忘记该AP，其处理代码如下：

@Override

public boolean onContextItemSelected(MenuItem item) {

if (mSelectedAccessPoint == null) {

return super.onContextItemSelected(item);

}

switch (item.getItemId()) {

case MENU_ID_CONNECT: {

if (mSelectedAccessPoint.networkId != INVALID_NETWORK_ID) {

if (!requireKeyStore(mSelectedAccessPoint.getConfig())) {

mWifiManager.connectNetwork(mSelectedAccessPoint.networkId);

}

} else if (mSelectedAccessPoint.security == AccessPoint.SECURITY_NONE) {

/** Bypass dialog for unsecured networks */

mSelectedAccessPoint.generateOpenNetworkConfig();

mWifiManager.connectNetwork(mSelectedAccessPoint.getConfig());

} else {

showConfigUi(mSelectedAccessPoint, true);

}

return true;

}

case MENU_ID_FORGET: {

mWifiManager.forgetNetwork(mSelectedAccessPoint.networkId);

return true;

}

case MENU_ID_MODIFY: {

showConfigUi(mSelectedAccessPoint, true);

return true;

}

return super.onContextItemSelected(item);

}

可以看出如果该AP已经经过配置，那么直接连接，如果没有经过配置且该AP没有密码，那么直接连接，否则则弹出配置对话框先进行配置(选择加密类型和输入密码)。

当点击AP列表中的某个AP时，直接根据该AP的情况进行处理，代码如下：

387 @Override

388 public boolean onPreferenceTreeClick(PreferenceScreen screen, Preference preference) {

389 if (preference instanceof AccessPoint) {

390 mSelectedAccessPoint = (AccessPoint) preference;

391 /** Bypass dialog for unsecured, unsaved networks */

392 if (mSelectedAccessPoint.security == AccessPoint.SECURITY_NONE &&

393 mSelectedAccessPoint.networkId == INVALID_NETWORK_ID) {

394 mSelectedAccessPoint.generateOpenNetworkConfig();

395 mWifiManager.connectNetwork(mSelectedAccessPoint.getConfig());

396 } else {

397 showConfigUi(mSelectedAccessPoint, false);

398 }

399 } else {

400 return super.onPreferenceTreeClick(screen, preference);

401 }

402 return true;

403 }

可以看出和长按菜单的处理逻辑相似。

当使用Setttings主界面或Settings/Wifi界面的Switcher开关Wifi时，处理代码会调用到mWifiEnabler的setSwitch方法，然后会通知其listener，涉及方法如下：

88 public void setSwitch(Switch switch_) {

89 if (mSwitch == switch_) return;

90 mSwitch.setOnCheckedChangeListener(null);

91 mSwitch = switch_;

92 mSwitch.setOnCheckedChangeListener(this);

94 final int wifiState = mWifiManager.getWifiState();

95 boolean isEnabled = wifiState == WifiManager.WIFI_STATE_ENABLED;

96 boolean isDisabled = wifiState == WifiManager.WIFI_STATE_DISABLED;

97 mSwitch.setChecked(isEnabled);

98 mSwitch.setEnabled(isEnabled || isDisabled);

99 }

100

101 public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

102 //Do nothing if called as a result of a state machine event

103 if (mStateMachineEvent) {

104 return;

105 }

106 // Show toast message if Wi-Fi is not allowed in airplane mode

107 if (isChecked && !WirelessSettings.isRadioAllowed(mContext, Settings.System.RADIO_WIFI)) {

108 Toast.makeText(mContext, R.string.wifi_in_airplane_mode, Toast.LENGTH_SHORT).show();

109 // Reset switch to off. No infinite check/listenenr loop.

110 buttonView.setChecked(false);

111 }

112

113 // Disable tethering if enabling Wifi

114 int wifiApState = mWifiManager.getWifiApState();

115 if (isChecked && ((wifiApState == WifiManager.WIFI_AP_STATE_ENABLING) ||

116 (wifiApState == WifiManager.WIFI_AP_STATE_ENABLED))) {

117 mWifiManager.setWifiApEnabled(null, false);

118 }

119

120 if (mWifiManager.setWifiEnabled(isChecked)) {

121 // Intent has been taken into account, disable until new state is active

122 mSwitch.setEnabled(false);

123 } else {

124 // Error

125 Toast.makeText(mContext, R.string.wifi_error, Toast.LENGTH_SHORT).show();

126 }

127 }

可以看出当不是AP时，是使能Wifi，默认行为是根据配置挑选出AP进行连接。

另外的两个类的解释：

WifiConfigController是MVC中的Controller

WifiDialog是单击的config对话框

连接和DHCP过程中显示的字符串xml文件如下：

In /packages/apps/Settings/res/values/arrays.xml

223

224

225  <skip />

226

227 <string-array name="wifi_status">

228

229 <item></item>

230

231 <item>Scanning\u2026</item>

232

233 <item>Connecting\u2026</item>

234

235 <item>Authenticating\u2026</item>

236

237 <item>Obtaining IP address\u2026</item>

238

239 <item>Connected</item>

240

241 <item>Suspended</item>

242

243 <item>Disconnecting\u2026</item>

244

245 <item>Disconnected</item>

246

247 <item>Unsuccessful</item>

248 </string-array>

至此UI界面响应部分介绍完毕，下面看WifiManager.

WifiManager是WifiService的客户端接口的封装类，WifiService是服务实现，接口是IWifiManager。

In IWifiManager.aidl

32interface IWifiManager {};

In WifiService.java

public class WifiService extends IWifiManager.Stub {};

In WifiManager.java, NOT the intermmediate file of IWifiManager.aidl

485 public WifiManager(IWifiManager service, Handler handler) {

486 mService = service;

487 mHandler = handler;

488 }

In ContextImpl.java每个Activity关联的Contect会得到WIFI_SERVICE，然后构造WifiManager封装类。代码如下：

449 registerService(WIFI_SERVICE, new ServiceFetcher() {

450 public Object createService(ContextImpl ctx) {

451 IBinder b = ServiceManager.getService(WIFI_SERVICE);

452 IWifiManager service = IWifiManager.Stub.asInterface(b);

453 returnnew WifiManager(service, ctx.mMainThread.getHandler());

454 }});

几个同步操作的控制流示例：

WifiSettings=>WifiManager::reconnect(…)()||||

=>WifiService:: reconnect ()=>WifiStateMachine :: reconnectCommand()

Scanner=>WifiManager::startScanActive()|||| =>WifiService::startScan(active)=>WifiStateMachine ::startScan(active)

WifiEnabler=> WifiManager::setWifiEnabled() |||| =>WifiService::setWifiEnabled()=>WifiStateMachine ::setWifiEnabled()

WifiManager中大部分同步命令都是这么个流程；耗时的异步命令则是通过AsyncChannel发送给WifiService.

WifiService Part structure

In WifiService.java

public class WifiService extends IWifiManager.Stub {};

WifiService线程的启动如下

In SystemServer.java

384 try {

385 Slog.i(TAG, "Wi-Fi P2pService");

386 wifiP2p = new WifiP2pService(context);

387 ServiceManager.addService(Context.WIFI_P2P_SERVICE, wifiP2p);

388 } catch (Throwable e) {

389 reportWtf("starting Wi-Fi P2pService", e);

390 }

391

392 try {

393 Slog.i(TAG, "Wi-Fi Service");

394 wifi = new WifiService(context);

395 ServiceManager.addService(Context.WIFI_SERVICE, wifi);

396 } catch (Throwable e) {

397 reportWtf("starting Wi-Fi Service", e);

398 }

WifiService的构造函数本质是启动了一个带有消息队列的线程做WifiService，两个Handler attach到该消息队列上。

428 HandlerThread wifiThread = new HandlerThread("WifiService");

429 wifiThread.start();

430 mAsyncServiceHandler = new AsyncServiceHandler(wifiThread.getLooper());

431 mWifiStateMachineHandler = new WifiStateMachineHandler(wifiThread.getLooper());

AsyncServiceHandler做为destHandler用于处理下行的来自WifiManager客户端的命令消息，而WifiStateMachineHandler做为srcHandler用于向WifiStateMachine.mSmhandler发送异步命令。现在的WifiStatemachine实现是和WifiService使用同一个looper，在同一个线程中，所以mAsyncServiceHandler、mWifiStateMachineHandler、WifiStateMachine.mSmhandler是使用同一个looper，运行在wifiThread中。WifiStateMachine籍由StateMachine具备有单独looper在单独线程运行的能力。

WifiSerivce作为一个service，WifiService.java在frameworks/base/services/java/com/android/server/目录下。但其实现使用的WifiStateMachine在frameworks/base/wifi/java/android/net/wifi/目录下。

WifiStateMachine状态机使用WifiNative wpa_ctrl和wpa_supplicant通讯， WifiMonitor监听wpa_supplicant的异步消息。因为WifiStateMachine的核心是状态机，所以其接口都是转换成命令投入状态机消息队列。WifiService传来的命令和WifiMonitor监听到的响应汇入WifiStateMachine的消息队列，驱动WifiStateMachine转动起来。

WifiStateMachine继承自StateMachine，是一个hierarchical state machine which processes messages and can have states arranged hierarchically，其细节参见StateMachine.java. WifiStateMachine的hierarchy如下图所示：

下面考察初始状态到Wifi使能扫描AP连接AP查询AP过程的状态机运转。

In WifiStateMachine.java

状态机会启动，进入InitialState状态。然后UI打开WifiEnabler最终WifiService:: setWifiEnabled会被执行到。相关代码如下：

553 public WifiStateMachine(Context context, String wlanInterface) {

649 if (DBG) setDbg(true);

650

651 //start the state machine

652 start();

653 }

680 public void setWifiEnabled(boolean enable) {

681 mLastEnableUid.set(Binder.getCallingUid());

682 if (enable) {

683 /* Argument is the state that is entered prior to load */

684 sendMessage(obtainMessage(CMD_LOAD_DRIVER, WIFI_STATE_ENABLING, 0));

685 sendMessage(CMD_START_SUPPLICANT);

686 } else {

687 sendMessage(CMD_STOP_SUPPLICANT);

688 /* Argument is the state that is entered upon success */

689 sendMessage(obtainMessage(CMD_UNLOAD_DRIVER, WIFI_STATE_DISABLED, 0));

690 }

691 }

在InitialState.enter()中，初始情况下WifiDriver是没有加载的，所以进入DriverUnloadedState状态；

然后setWifiEnabled向状态机发出CMD_LOAD_DRIVER with WIFI_STATE_ENABLING和CMD_START_SUPPLICANT两个命令。

在DriverUnloadedState状态下，处理CMD_LOAD_DRIVER命令，向WifiP2pService发送WIFI_ENABLE_PENDING命令，也就是说通知WifiP2pService需要退出要启用Wifi了，因为WifiService和WifiP2pService同一时刻只能使用一个，然后转到WaitForP2pDisableState状态等待WifiP2pService的响应。

在WaitForP2pDisableState状态下收到WifiP2pService的响应WIFI_ENABLE_PROCEED，转到DriverLoadingState状态加载Wifi driver；对于其它请求会deferMessage到以后状态处理。

在DriverLoadingState状态启用线程异步加载Wifi driver，当加载成功时，向状态机自身发送消息CMD_LOAD_DRIVER_SUCCESS驱动状态机转换到DriverLoadedState，加载失败则发送消息CMD_LOAD_DRIVER_FAILED驱动状态机转换到DriverFailedState状态（会经由DriverUnloadedState）。

在DriverLoadedState状态下处理setWifiEnabled发出的defer到此的第二个命令CMD_START_SUPPLICANT，加载网卡芯片固件，启动wpa_supplicant，启动WifiMonitor接收wpa_supplicant的消息，转换状态到SupplicantStartingState等待WifiMonitor的事件（wpa_supplicant接入成功事件）。

在SupplicantStartingState状态下收到WifiMonitor. SUP_CONNECTION_EVENT表接入wpa_supplicant成功，regulate国家代号，初始化一些表征wpa_s的字段，转换状态至DriverStartedState；对于其它命令，defer处理。

经SupplicantStartedState.enter()和DriverStartedState.enter()中使用CMD_SET_COUNTRY_CODE和CMD_SET_FREQUENCY_BAND设置国家代号和频段，在本状态处理这两个命令；这两个命令是要发送给芯片的，所以在固件和驱动加载好后发送。设置好频段后，就向自身发送消息CMD_START_SCAN启动一次active scan。然后经由状态ConnectModeState转换状态至DisconnectedState。

在DisconnectedState下收到扫描结果WifiMonitor.SCAN_RESULTS_EVENT，消息路由给父状态SupplicantStartedState的processMessage进行处理，获取扫描结果并保存。在此状态下SupplicantStartedState处理与AP配置相关的命令，ConnectModeState处理与AP连接相关的命令。例如可以配置某个AP，然后请求connectNetwork，对于CMD_CONNECT_NETWORK，会使用Connect相关状态ConnectModeState.processMessage()处理，启动AP关联，然后转换状态到DisconnectingState与旧AP断开连接与新AP建立连接。

在DisconnectingState状态收到关联到新AP成功消息WifiMonitor.NETWORK_CONNECTION_EVENT后，使用ConnectModeState.processMessage处理，记录关联上的SSID，BSSID，获取AP信号强度和速度，广播消息，转换状态至ConnectingState进行IP获取。

在ConnectingState.enter()中使用静态IP或DHCP获取IP，配置IP，成功则转入ConnectedState状态。

在ConnectedState状态下，可以处理配置AP、连接新的AP、断开连接等，还有扫描请求，另外还要查询当前连接AP的信号强度和网络流量信息，在状态栏显示Wifi状态图标。这时通过CMD_RSSI_POLL命令实现的，当WifiService构造时，允许enableRssiPolling，一次CMD_ENABLE_RSSI_POLL会引发定时的CMD_RSSI_POLL，当屏幕未关闭时，CMD_RSSI_POLL就会定时向自身状态机发送；然后ConnectedState.processMessage调用fetchRssiAndLinkSpeedNative()处理CMD_RSSI_POLL。

以上是扫描、关联的状态转换过程，状态转化图大致如下：

其余断开连接、扫描模式等状态转换根据情景，参见WifiStateMachine.java代码。

WifiStateMachine状态机和wpa_supplicant通信，因为wpa_supplicant的接口是两个阻塞模式的unix domain socket，一个用于控制一个用于向请求者返回异步响应，所以决定了WifiStateMachine和wpa_supplicant之间的软件结构是有一个接收线程阻塞在读端口上，而写端口时根据速率匹配看是否需要单独的发送进程。

WifiStateMachine和wpa_supplicant之间的数据通信量是很小的，所以不需要单独的发送进程，只需要一个常接收阻塞的接收线程即可，这个线程就是WifiMonitor。WifiMonitor就是个ReceiverThread加消息协议转换。WifiMonitor在使用unix domain socket ctrl interface时是poll在socket上，有wpa_supplicant发回的数据时，阻塞的recv返回。

两个结构图如下：

WifiStateMachine的方法中同步的带有’sync’字样，异步的是直接发送消息到状态机消息队列，通过WifiMonitor异步收集结果。同步和异步都是基于AsyncChannel，同步只不过是在异步的AsyncChannel基础上加了同步（阻塞）保证机制。

WifiMonitor

294 class MonitorThread extends Thread {

295 public MonitorThread() {

296 super("WifiMonitor");

297 }

298

299 public void run() {

300

301 if (connectToSupplicant()) {

302 // Send a message indicating that it is now possible to send commands

303 // to the supplicant

304 mStateMachine.sendMessage(SUP_CONNECTION_EVENT);

305 } else {

306 mStateMachine.sendMessage(SUP_DISCONNECTION_EVENT);

307 return;

308 }

309

310 //noinspection InfiniteLoopStatement

311 for (;;) {

312 String eventStr = WifiNative.waitForEvent();

313

……..

}

android_net_wifi_Wifi.cpp

120static jboolean android_net_wifi_loadDriver(JNIEnv* env, jobject)

121{

122 return (jboolean)(::wifi_load_driver() == 0);

123}

290static jboolean android_net_wifi_reconnectCommand(JNIEnv* env, jobject)

291{

292 return doBooleanCommand("OK", "RECONNECT");

293}

WifiNative.java中使用reconnectCommand方法时没有检查返回值，所以消息估计是异步传回。

static jboolean doBooleanCommand(const char* expect, const char* fmt, ...)

static int doCommand(const char *cmd, char *replybuf, int replybuflen)

call

875int wifi_command(const char *command, char *reply, size_t *reply_len) @ wifi_bcm.c

876{

877 return wifi_send_command(ctrl_conn, command, reply, reply_len);

878}

Wifi driver加载

bcm4330的wifi驱动可能是bcmdhd.so或dhd.so

#WIFI_DRIVER_MODULE_PATH := "/system/etc/bcm4330/dhd.ko"

insmod(DRIVER_MODULE_PATH, DRIVER_MODULE_ARG)

也可能是builtIn的

LOGI("Using BuildIn WiFi driver");

property_set(DRIVER_PROP_NAME, "ok");

wpa_ctrl连接wpa_supplicant

wpa_supplicant启动后会根据wpa_supplicant.conf配置自己。ctrl_interface=value这项就是ctrl_interface对应unix domain socket(DGRAM)的服务端口文件名，和wpa_cli等约定连接端口。value可以是ifacename或者DIR=一个目录。

wifi_bcm.c中的update_ctrl_interface，就是从config file里面找ctrl_interface=wlan0这项，生成unix domain socket的监听端口文件名。当ctrl_interface=wlan0时，wpa_supplicant系统会生成/dev/socket/wpa_wlan0。当是一个目录的时候，可能在其下生成什么文件名。

目标文件名是/dev/socket/wpa_wlan0，是socket(DGRAM)的服务端，这个是由wpa_supplicant打开的。参见init.Manufacture.rc。wpa_cli使用wpa_ctrl_open去socket connect连接这个服务名。Android修改了wpa_supplicant打开socket的代码，是在init.Manufacture.rc中在init阶段打开，wpa_supplicant在wpa_supplicant_ctrl_iface_init()时查找该socket直接使用。注意由于以下没有-g选项，所以wpa_supplicant_global_ctrl_iface_init()时的params.ctrl_interface is NULL。选项中传入的interface会wpa_supplicant_add_iface(global, &ifaces[i]) @main.c

service wpa_supplicant /system/bin/logwrapper /system/bin/wpa_supplicant -iwlan0 -puse_p2p_group_interface=1 -Dnl80211

class late_start

user root

group wifi inet

socket wpa_wlan0 dgram 660 wifi wifi

disabled

oneshot

使用单独的wpa_cli(link with wpa_ctrl.c)时，使用如下命令去连接wpa_supplicant

wpa_cli -p /dev/socket/ -i wpa_wlan0

连接成功后，wpa_cli程序会在某个目录下新建两个unix domain socket的两个local文件名。

srw-rw---- system wifi 2013-04-10 17:33 wpa_ctrl_337-1

srw-rw---- system wifi 2013-04-10 17:33 wpa_ctrl_337-2

该目录由以下两个宏指定

hardware/libhardware_legacy/wifi/Android.mk

3LOCAL_CFLAGS += -DCONFIG_CTRL_IFACE_CLIENT_DIR=\"/data/misc/wifi/sockets\"

4LOCAL_CFLAGS += -DCONFIG_CTRL_IFACE_CLIENT_PREFIX=\"wpa_ctrl_\"

其中/data/misc/wifi/sockets是使用wpa_cli库接口建立unix domain socket时的本地文件目录。这两个宏构成如/data/misc/wifi/sockets/ wpa_ctrl_pid-nn的本地文件名，就是unix domain socket的本地文件名。这儿和本地文件名bind的好处是把pid加到文件名中，server端因为是DGRAM socket，不能accept，recvfrom就可以得到该client socket的地址可以知道socket的pid，另外本地可以使用文件名chown/chmod。

wpa_cli使用wpa_ctrl_open创建两个socket，bind本地文件名，connect wpa_supplicant接口名(对于DGRAM，connect并没有真正的作用，仅是做peer addr绑定)；wpa_supplicant不需要accept直接在其socket上recvfrom；当wpa _cli wpa_ctrl_attach其中一个时，从该socket读出”ATTACH”/”DETACH”，然后可以这个socket以后是monitor socket，因此以后不必在从此socket接收数据。

wpa_cli为了在wpa_ctrl_request出错时，退出recv(monitor_socket)，用了socketpair中的读端socket和monitor_socket一起select，从而出错时正常退出。

具体参见wpa_ctrl.c文件。

当wpa_supplicant和driver和firmware不是手动加载的时候，直接打开WifiEnabler，则已打开的wpa_ctrl的事件也会输出到wpa_cli。wpa_supplicant会把消息输出到attach到其上的socket上，代码在wpa_supplicant_ctrl_iface_send()中把msg送到每个monitor socket。

247static void wpa_supplicant_ctrl_iface_msg_cb(void *ctx, int level,

248 const char *txt, size_t len)

249{

250 struct wpa_supplicant *wpa_s = ctx;

251 if (wpa_s == NULL || wpa_s->ctrl_iface == NULL)

252 return;

253 wpa_supplicant_ctrl_iface_send(wpa_s->ctrl_iface, level, txt, len);

254}

可以修改wpa_cli的源码，不到monitor_socket attach或者做了attach收到消息不打印，从而避免干扰。但是需要记住，同时有两个wpa_ctrl程序在操作wpa_supplicant。

wpa_supplicant的启动

int wifi_start_supplicant_common(const char *config_file)

{

property_get("wifi.interface", iface, WIFI_TEST_INTERFACE);

property_get("persist.wpa_supplicant.debug", supp_debug, "false");

if (strcmp(supp_debug, "true") == 0) {

SLOGI("persist.wpa_supplicant.debug property true");

snprintf(daemon_cmd, PROPERTY_VALUE_MAX, "%s:-i%s -c%s -ddd", SUPPLICANT_NAME, iface, config_file);

} else {

SLOGI("persist.wpa_supplicant.debug property false");

snprintf(daemon_cmd, PROPERTY_VALUE_MAX, "%s:-i%s -c%s", SUPPLICANT_NAME, iface, config_file);

}

property_set("ctl.start",daemon_cmd);

}

启动中会有log输出；前一条log表明wpa_supplicant的log输出到logger。

9738 log 0:00 /system/bin/logwrapper /system/bin/wpa_supplicant -iwlan0 -puse_p2p_group_interface=1 -Dnl80211 -iwlan0 -c/data/misc/wifi/wpa_supplicant.conf -ddd

9740 wifi 0:23 /system/bin/wpa_supplicant -iwlan0 -puse_p2p_group_interface=1 -Dnl80211 -iwlan0 -c/data/misc/wifi/wpa_supplicant.conf -ddd

注意 –g选项表示全局ctrl_interface，是从选项传入，对应wpa_supplicant源码中的global_ctrl_interface；以后加入的interface，对应源码中的ctrl_interface；如果global有选项指定覆盖新加入interface的选项，那么后加入的interface对应的参数会被global覆盖选项指定的参数覆盖掉。其余选项指定参数会覆盖config文件中的参数。优先级是覆盖选项参数>选项参数>config文件中参数。可覆盖的主要是driver和ctrl_interface。

wpa_supplicant结构

总体结构。UML struct wpa_supplicant struct wpa_interface。具体组织结构和数据结构参见developers guidehttp://w1.fi/wpa_supplicant/wpa_supplicant-devel.pdf

wpa_supplicant使用eloop接收unix domain socket传来的命令，使用libnl和nl80211交互。

接收wpa_supplicant客户端control命令的unix domain socket函数主要入口是wpa_supplicant_ctrl_iface_receive，接收到命令数据后，除了ATTACH/DETACH直接处理，会调用wpa_supplicant_ctrl_iface_process处理；ATTACH/DETACH其实是monitor_event端口发过来的，control端口发来的命令都是交由wpa_supplicant_ctrl_iface_process处理。

wpa_supplicant_ctrl_iface_process

{

3286 } else if (os_strcmp(buf, "RECONNECT") == 0) {

3287 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)

3288 reply_len = -1;

3289 else if (wpa_s->disconnected) {

3290 wpa_s->disconnected = 0;

3291 wpa_s->reassociate = 1;

3292 wpa_supplicant_req_scan(wpa_s, 0, 0);

3293 }

3521 } else if (os_strcmp(buf, "SCAN") == 0) {

3522 if (wpa_s->wpa_state == WPA_INTERFACE_DISABLED)

3523 reply_len = -1;

3524 else {

3525 if (!wpa_s->scanning &&

3526 ((wpa_s->wpa_state <= WPA_SCANNING) ||

3527 (wpa_s->wpa_state == WPA_COMPLETED))) {

3528 wpa_s->scan_req = 2;

3529 wpa_supplicant_req_scan(wpa_s, 0, 0);

3530 } else {

3531 wpa_printf(MSG_DEBUG, "Ongoing scan action - "

3532 "reject new request");

3533 reply_len = os_snprintf(reply, reply_size,

3534 "FAIL-BUSY\n");

3535 }

3536 }

3537 } else if (os_strcmp(buf, "SCAN_RESULTS") == 0) {

3538 reply_len = wpa_supplicant_ctrl_iface_scan_results(

3539 wpa_s, reply, reply_size);

3540 } else if (os_strncmp(buf, "SELECT_NETWORK ", 15) == 0) {

3541 if (wpa_supplicant_ctrl_iface_select_network(wpa_s, buf + 15))

3542 reply_len = -1;

3543 } else if (os_strncmp(buf, "ENABLE_NETWORK ", 15) == 0) {

3544 if (wpa_supplicant_ctrl_iface_enable_network(wpa_s, buf + 15))

3545 reply_len = -1;

3546 } else if (os_strncmp(buf, "DISABLE_NETWORK ", 16) == 0) {

3547 if (wpa_supplicant_ctrl_iface_disable_network(wpa_s, buf + 16))

3548 reply_len = -1;

3549 } else if (os_strcmp(buf, "ADD_NETWORK") == 0) {

3550 reply_len = wpa_supplicant_ctrl_iface_add_network(

3551 wpa_s, reply, reply_size);

3552 } else if (os_strncmp(buf, "REMOVE_NETWORK ", 15) == 0) {

3553 if (wpa_supplicant_ctrl_iface_remove_network(wpa_s, buf + 15))

3554 reply_len = -1;

3555 } else if (os_strncmp(buf, "SET_NETWORK ", 12) == 0) {

3556 if (wpa_supplicant_ctrl_iface_set_network(wpa_s, buf + 12))

3557 reply_len = -1;

3558 } else if (os_strncmp(buf, "GET_NETWORK ", 12) == 0) {

3559 reply_len = wpa_supplicant_ctrl_iface_get_network(

3560 wpa_s, buf + 12, reply, reply_size);

3561#ifndef CONFIG_NO_CONFIG_WRITE

3562 } else if (os_strcmp(buf, "SAVE_CONFIG") == 0) {

3563 if (wpa_supplicant_ctrl_iface_save_config(wpa_s))

3564 reply_len = -1;

3565#endif /* CONFIG_NO_CONFIG_WRITE */

3566 } else if (os_strncmp(buf, "GET_CAPABILITY ", 15) == 0) {

3567 reply_len = wpa_supplicant_ctrl_iface_get_capability(

3568 wpa_s, buf + 15, reply, reply_size);

3569 } else if (os_strncmp(buf, "AP_SCAN ", 8) == 0) {

3570 if (wpa_supplicant_ctrl_iface_ap_scan(wpa_s, buf + 8))

3571 reply_len = -1;

3572 } else if (os_strncmp(buf, "SCAN_INTERVAL ", 14) == 0) {

}

wpa_supplicant_ctrl_iface_process对于命令要么在wpa_supplicant内通过wpa_supplicant_dddd_nnnn自己处理，要么交给driver wpa_drv_dddd_nnnn去处理。命令处理或发送给driver后，将结果直接通过sendto源地址。

异步CTRL-EVENT-消息是通过wpa_msg(MSG_INFO)和wpa_msg_ctrl(MSG_INFO)发送给monitor socket，如果修改成都使用同一接口则风格更统一，更具可读性。

wpa_supplicant_driver通过libnl和nl80211网卡驱动通信，详述driver_nl80211和kernel通信的接口。主要使用了一个普通socket、两个NETLINK_GENERIC socket、一个NETLINK_ROUTE socket、一个/dev/rkfill文件，外加一个monitor PACKET RAW socket。普通socket使用网卡相关IOCTL和指定的网卡通信，具体见normal socket ioctl to net interface ioctl 文；两个NETLINK_GENERTIC socket一个用于nl80211 control一个用于nl80211 event接收，接收的event有nl80211 scan、nl80211 mlme、nl80211 regulatory还有registerred frame；一个NETLINK_ROUTE主要用于nl80211 route event接收处理link layer事件；/dev/rfkill用于rfkill；而monitor socket用于实现wpa_supplicant AP hotspot。

这几个socket创建如下：

ioctl_socket = socket(PF_INET, SOCK_DGRAM, 0);

genl_ctrl_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_GENERTIC);

genl_event_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_GENERTIC);

nl_route_event_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

monitor_socket = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));

Event、monitor和/dev/rfkill的recv_cb函数如下：

genl_event_socket

=> wpa_driver_nl80211_event_receive()

=> process_event() for (NL_CB_VALID - NL_CB_CUSTOM)

nl_route_event_socket

=> netlink_receive()

=> wpa_driver_nl80211_event_rtm_newlink() for RTM_NEWLINK

=> wpa_driver_nl80211_event_rtm_dellink() for RTM_DELLINK

=> wpa_driver_nl80211_event_link()

=> wpa_supplicant_event()

/dev/rfkill

=> rfkill_receive()

=> wpa_driver_nl80211_rfkill_blocked()

=> wpa_driver_nl80211_rfkill_unblocked()

monitor_socket

=> handle_monitor_read()

875int wifi_command(const char *command, char *reply, size_t *reply_len) @ wifi_bcm.c

发送命令到wpa_supplicant的监听socket上，该socket的recv函数是wpa_supplicant_ctrl_iface_receive，在wpa_supplicant的初始化过程中注册

main()

=> wpa_supplicant_add_iface

=> wpa_supplicant_init_iface

=> wpa_supplicant_ctrl_iface_init

=> eloop_register_read_sock.

socket receive cb注册是使用eloop做的，以nl80211 event socket为例，是在wpa_driver_nl80211_init_nl中，wpa_driver_nl80211_event_receive注册到netlink socket的读处理上。

eloop_register_read_sock(nl_socket_get_fd(drv->nl_handle_event),

wpa_driver_nl80211_event_receive, drv,

drv->nl_handle_event);

下面大致介绍扫描和连接的过程。首先是扫描的过程，

在客户端命令扫描wpa_supplicant_ctrl_interface_process处理”SCAN”命令时，会wpa_supplicant_req_scan()；其余连接过程也可能会请求扫描一下看该AP是否还存在，如

wpa_supplicant_ctrl_iface_select_network - Select the network and disable others

@ssid: wpa_ssid structure for a configured network or %NULL for any network

wpa_supplicant_ctrl_iface_select_network => wpa_supplicant_select_network =>wpa_supplicant_req_scan(wpa_s, 0, 0);

wpa_supplicant_enable_network - Mark a configured network as enabled

@ssid: wpa_ssid structure for a configured network or %NULL

wpa_supplicant_ctrl_iface_enable_network => wpa_supplicant_enable_network =>wpa_supplicant_req_scan(wpa_s, 0, 0);

wpa_supplicant_req_scan具体调用流程如下：

void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)进行延迟scan请求。

static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx);进行扫描触发。

int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s, struct wpa_driver_scan_params *params)真正做触发scan。

int wpa_drv_scan(struct wpa_supplicant *wpa_s, struct wpa_ssid **ssid_ptr)调用wpa_driver user_space驱动如driver_nl80211进行扫描。

static int wpa_driver_nl80211_scan(void *priv, struct wpa_driver_scan_params *params)发送NL80211_CMD_TRIGGER_SCAN给kernel驱动。

wpa_supplicant_scan()会根据不同ap_scan做扫描或根据驱动关联结果发送关联event。大多数情况下ap_scan为1，trigger scan。

当内核扫描完成后会发送NL80211_CMD_NEW_SCAN_RESULTS通知，process_event() @ driver_nl80211.c调用send_scan_event()调用wpa_supplicant_event(drv->ctx, EVENT_SCAN_RESULTS, &event) @ event.c处理。

void wpa_supplicant_event(void *ctx, enum wpa_event_type event, union wpa_event_data *data)

2155 case EVENT_SCAN_RESULTS:

2156 wpa_supplicant_event_scan_results(wpa_s, data);

2157 break;

接收扫描结果并且根据配置从扫描结果中选择AP进行连接。下面着重考察连接过程。

wpa_supplicant_event_scan_results

_wpa_supplicant_event_scan_results => wpa_supplicant_get_scan_results()

wpa_supplicant_pick_network

wpa_supplicant_select_bss

wpa_scan_res_match

现在的是match之后，下一个是什么过程。要找到：从connect命令后找，启动搜索，搜索结果，从configed APs中匹配AP。

连接前启动扫描，扫描结果匹配后，自然是连接。就从_wpa_supplicant_event_scan_results在pick network之后看。

if (selected) {

int skip;

skip = !wpa_supplicant_need_to_roam(wpa_s, selected, ssid, scan_res);

wpa_scan_results_free(scan_res);

if (skip)

return 0;

wpa_supplicant_connect(wpa_s, selected, ssid);

wpa_supplicant_rsn_preauth_scan_results(wpa_s);

}

wpa_supplicant_connect()会根据状态调用wpa_supplicant_associate(wpa_s,selected, ssid)进行AP关联。另外wpa_supplicant_ctrl_iface_roam()处理时也会调用wpa_supplicant_connect()。

wpa_supplicant_associate是连接和验证的入口。_wpa_supplicant_event_scan_results在wpa_supplicant_connect()连接不成功时，会wpa_supplicant_associate(wpa_s,NULL, ssid)去尝试关联其它的AP；在wpa_supplicant_scan()中根据不同ap_scan模式和配置，也会直接调用wpa_supplicant_assoc(wpa_s,NULL, ssid)；或者在sme_event_auth()即通过auth后进行特定AP的关联wpa_supplicant_assoc(wpa_s,wpa_s->current_bss, wpa_s->current_ssid)，这是Authenticate和Associate分步的情况。

wpa_supplicant_associate

=> wpa_drv_associate

=> wpa_driver_nl80211_associate when drvier_nl80211 is used.

=> wpa_driver_nl80211_ibss for IBSS mode.

=> wpa_driver_nl80211_connect for INFRA non-SME mode

=> or send NL80211_CMD_ASSOCIATE for SME mode after AUTHENTICATED

wpa_driver_nl80211_ibss首先将驱动和固件设置到IBSS工作模式，然后发送JOIN_IBSS命令。

4709static int wpa_driver_nl80211_ibss(struct wpa_driver_nl80211_data *drv,

4710 struct wpa_driver_associate_params *params)

4711{

4712 struct nl_msg *msg;

4713 int ret = -1;

4714 int count = 0;

4715

4716 wpa_printf(MSG_DEBUG, "nl80211: Join IBSS (ifindex=%d)", drv->ifindex);

4717

4718 if (wpa_driver_nl80211_set_mode(&drv->first_bss, params->mode)) {

4719 wpa_printf(MSG_INFO, "nl80211: Failed to set interface into "

4720 "IBSS mode");

4721 return -1;

4722 }

4723

4724retry:

4725 msg = nlmsg_alloc();

4726 if (!msg)

4727 return -1;

4728

4729 genlmsg_put(msg, 0, 0, genl_family_get_id(drv->nl80211), 0, 0,

4730 NL80211_CMD_JOIN_IBSS, 0);

4731 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, drv->ifindex);

4732

4733 if (params->ssid == NULL || params->ssid_len > sizeof(drv->ssid))

4734 goto nla_put_failure;

4735

4736 wpa_hexdump_ascii(MSG_DEBUG, " * SSID",

4737 params->ssid, params->ssid_len);

4738 NLA_PUT(msg, NL80211_ATTR_SSID, params->ssid_len,

4739 params->ssid);

4740 os_memcpy(drv->ssid, params->ssid, params->ssid_len);

4741 drv->ssid_len = params->ssid_len;

4742

4743 wpa_printf(MSG_DEBUG, " * freq=%d", params->freq);

4744 NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_FREQ, params->freq);

4745

4746 ret = nl80211_set_conn_keys(params, msg);

4747 if (ret)

4748 goto nla_put_failure;

4749

4750 if (params->wpa_ie) {

4751 wpa_hexdump(MSG_DEBUG,

4752 " * Extra IEs for Beacon/Probe Response frames",

4753 params->wpa_ie, params->wpa_ie_len);

4754 NLA_PUT(msg, NL80211_ATTR_IE, params->wpa_ie_len,

4755 params->wpa_ie);

4756 }

4757

4758 ret = send_and_recv_msgs(drv, msg, NULL, NULL);

4759 msg = NULL;

4760 if (ret) {

4761 wpa_printf(MSG_DEBUG, "nl80211: Join IBSS failed: ret=%d (%s)",

4762 ret, strerror(-ret));

4763 count++;

4764 if (ret == -EALREADY && count == 1) {

4765 wpa_printf(MSG_DEBUG, "nl80211: Retry IBSS join after "

4766 "forced leave");

4767 nl80211_leave_ibss(drv);

4768 nlmsg_free(msg);

4769 goto retry;

4770 }

4771

4772 goto nla_put_failure;

4773 }

4774 ret = 0;

4775 wpa_printf(MSG_DEBUG, "nl80211: Join IBSS request sent successfully");

4776

4777nla_put_failure:

4778 nlmsg_free(msg);

4779 return ret;

4780}

INFRA模式时，wpa_driver_nl80211_connect被调用之前会设置网卡工作模式为BSS模式。connect过程向驱动发送NL80211_CMD_CONNECT。

4783static int wpa_driver_nl80211_connect(

4784 struct wpa_driver_nl80211_data *drv,

4785 struct wpa_driver_associate_params *params)

4786{

4787 struct nl_msg *msg;

4788 enum nl80211_auth_type type;

4789 int ret = 0;

4790 int algs;

4791

4792 msg = nlmsg_alloc();

4793 if (!msg)

4794 return -1;

4795

4796 wpa_printf(MSG_DEBUG, "nl80211: Connect (ifindex=%d)", drv->ifindex);

4797 genlmsg_put(msg, 0, 0, genl_family_get_id(drv->nl80211), 0, 0,

4798 NL80211_CMD_CONNECT, 0);

4799

4800 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, drv->ifindex);

4801 if (params->bssid) {

4802 wpa_printf(MSG_DEBUG, " * bssid=" MACSTR,

4803 MAC2STR(params->bssid));

4804 NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, params->bssid);

4805 }

4806 if (params->freq) {

4807 wpa_printf(MSG_DEBUG, " * freq=%d", params->freq);

4808 NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_FREQ, params->freq);

4809 }

4810 if (params->ssid) {

4811 wpa_hexdump_ascii(MSG_DEBUG, " * SSID",

4812 params->ssid, params->ssid_len);

4813 NLA_PUT(msg, NL80211_ATTR_SSID, params->ssid_len,

4814 params->ssid);

4815 if (params->ssid_len > sizeof(drv->ssid))

4816 goto nla_put_failure;

4817 os_memcpy(drv->ssid, params->ssid, params->ssid_len);

4818 drv->ssid_len = params->ssid_len;

4819 }

4820 wpa_hexdump(MSG_DEBUG, " * IEs", params->wpa_ie, params->wpa_ie_len);

4821#ifdef WAPI

4822 wpa_printf(MSG_DEBUG, "%s: params->wpa_ie_len=%d\n", __FUNCTION__, params->wpa_ie_len);

4823 wpa_printf(MSG_DEBUG, "%s: params->wpa_ie: [%02x][%02x][%02x][%02x]\n",

4824 __FUNCTION__, params->wpa_ie[0], params->wpa_ie[1], params->wpa_ie[2], params->wpa_ie[3]);

4825

4826 if (params->wpa_ie[0] == WLAN_EID_WAPI) {

4827 drv->ap_wapi_ie = params->ap_wapi_ie ;

4828 drv->ap_wapi_ie_len = params->ap_wapi_ie_len ;

4829 }

4830#endif

4831

4832 if (params->wpa_ie)

4833 NLA_PUT(msg, NL80211_ATTR_IE, params->wpa_ie_len,

4834 params->wpa_ie);

4835

4836 algs = 0;

4837 if (params->auth_alg & WPA_AUTH_ALG_OPEN)

4838 algs++;

4839 if (params->auth_alg & WPA_AUTH_ALG_SHARED)

4840 algs++;

4841 if (params->auth_alg & WPA_AUTH_ALG_LEAP)

4842 algs++;

4843 if (algs > 1) {

4844 wpa_printf(MSG_DEBUG, " * Leave out Auth Type for automatic "

4845 "selection");

4846 goto skip_auth_type;

4847 }

4848

4849 if (params->auth_alg & WPA_AUTH_ALG_OPEN)

4850 type = NL80211_AUTHTYPE_OPEN_SYSTEM;

4851 else if (params->auth_alg & WPA_AUTH_ALG_SHARED)

4852 type = NL80211_AUTHTYPE_SHARED_KEY;

4853 else if (params->auth_alg & WPA_AUTH_ALG_LEAP)

4854 type = NL80211_AUTHTYPE_NETWORK_EAP;

4855 else if (params->auth_alg & WPA_AUTH_ALG_FT)

4856 type = NL80211_AUTHTYPE_FT;

4857#ifdef WAPI

4858 else if (params->wpa_ie[0] == WLAN_EID_WAPI) {

4859 type = NL80211_AUTHTYPE_OPEN_SYSTEM;

4860 }

4861#endif

4862

4863 else

4864 goto nla_put_failure;

4865

4866 wpa_printf(MSG_DEBUG, " * Auth Type %d", type);

4867 NLA_PUT_U32(msg, NL80211_ATTR_AUTH_TYPE, type);

4868

4869skip_auth_type:

4870 if (params->wpa_ie && params->wpa_ie_len) {

4871 enum nl80211_wpa_versions ver;

4872

4873 if (params->wpa_ie[0] == WLAN_EID_RSN)

4874 ver = NL80211_WPA_VERSION_2;

4875#ifdef WAPI

4876 else if (params->wpa_ie[0] == WLAN_EID_WAPI) { /* wapi */

4877 wpa_printf(MSG_DEBUG, " * IW_AUTH_WAPI_VERSION_1");

4878 ver = NL80211_WAPI_VERSION_1;

4879 }

4880#endif

4881 else

4882 ver = NL80211_WPA_VERSION_1;

4883

4884 wpa_printf(MSG_DEBUG, " * WPA Version %d", ver);

4885 NLA_PUT_U32(msg, NL80211_ATTR_WPA_VERSIONS, ver);

4886 }

4887#ifdef WAPI

4888 else if(params->wpa_ie[0] == WLAN_EID_WAPI) {

4889 enum nl80211_wpa_versions ver;

4890

4891 ver = NL80211_WAPI_VERSION_1;

4892 NLA_PUT_U32(msg, NL80211_ATTR_WPA_VERSIONS, ver);

4893 wpa_printf(MSG_DEBUG, " * NO params->wpa_ie && params->wpa_ie_len");

4894 }

4895#endif

4896

4897 if (params->pairwise_suite != CIPHER_NONE) {

4898 int cipher;

4899

4900 switch (params->pairwise_suite) {

4901 case CIPHER_WEP40:

4902 cipher = WLAN_CIPHER_SUITE_WEP40;

4903 break;

4904 case CIPHER_WEP104:

4905 cipher = WLAN_CIPHER_SUITE_WEP104;

4906 break;

4907 case CIPHER_CCMP:

4908 cipher = WLAN_CIPHER_SUITE_CCMP;

4909 break;

4910 case CIPHER_TKIP:

4911 default:

4912 cipher = WLAN_CIPHER_SUITE_TKIP;

4913 break;

4914 }

4915#ifdef WAPI

4916 if (params->wpa_ie[0] == WLAN_EID_WAPI) { /* wapi */

4917 wpa_printf(MSG_DEBUG, " * Set SUITES_PAIRWISE to WLAN_CIPHER_SUITE_SMS4");

4918 cipher = WLAN_CIPHER_SUITE_SMS4;

4919 }

4920#endif

4921 NLA_PUT_U32(msg, NL80211_ATTR_CIPHER_SUITES_PAIRWISE, cipher);

4922#ifdef WAPI

4923 } else {

4924 if (params->wpa_ie[0] == WLAN_EID_WAPI) { /* wapi */

4925 int cipher;

4926 wpa_printf(MSG_DEBUG, " * Set SUITES_PAIRWISE to WLAN_CIPHER_SUITE_SMS4");

4927 cipher = WLAN_CIPHER_SUITE_SMS4;

4928

4929 params->pairwise_suite = WLAN_CIPHER_SUITE_SMS4;

4930

4931 NLA_PUT_U32(msg, NL80211_ATTR_CIPHER_SUITES_PAIRWISE, cipher);

4932

4933 }

4934#endif

4935

4936 }

4937

4938 if (params->group_suite != CIPHER_NONE) {

4939 int cipher;

4940

4941 switch (params->group_suite) {

4942 case CIPHER_WEP40:

4943 cipher = WLAN_CIPHER_SUITE_WEP40;

4944 break;

4945 case CIPHER_WEP104:

4946 cipher = WLAN_CIPHER_SUITE_WEP104;

4947 break;

4948 case CIPHER_CCMP:

4949 cipher = WLAN_CIPHER_SUITE_CCMP;

4950 break;

4951 case CIPHER_TKIP:

4952 default:

4953 cipher = WLAN_CIPHER_SUITE_TKIP;

4954 break;

4955 }

4956 NLA_PUT_U32(msg, NL80211_ATTR_CIPHER_SUITE_GROUP, cipher);

4957 }

4958

4959 if (params->key_mgmt_suite == KEY_MGMT_802_1X ||

4960 params->key_mgmt_suite == KEY_MGMT_PSK

4961#ifdef WAPI

4962 || params->key_mgmt_suite == KEY_MGMT_WAPI_PSK

4963 || params->key_mgmt_suite == KEY_MGMT_WAPI_CERT

4964#endif

4965 ) {

4966 int mgmt = WLAN_AKM_SUITE_PSK;

4967 switch (params->key_mgmt_suite) {

4968 case KEY_MGMT_802_1X:

4969 mgmt = WLAN_AKM_SUITE_8021X;

4970 break;

4971 case KEY_MGMT_PSK:

4972#ifdef WAPI

4973 mgmt = WLAN_AKM_SUITE_PSK;

4974 break;

4975 case KEY_MGMT_WAPI_PSK:

4976 mgmt = WLAN_AKM_SUITE_WAPI_PSK;

4977 break;

4978 case KEY_MGMT_WAPI_CERT:

4979 mgmt = WLAN_AKM_SUITE_WAPI_CERT;

4980 break;

4981#endif

4982 default:

4983 mgmt = WLAN_AKM_SUITE_PSK;

4984 break;

4985 }

4986

4987 NLA_PUT_U32(msg, NL80211_ATTR_AKM_SUITES, mgmt);

4988 }

4989

4990 ret = nl80211_set_conn_keys(params, msg);

4991 if (ret)

4992 goto nla_put_failure;

4993

4994 ret = send_and_recv_msgs(drv, msg, NULL, NULL);

4995 msg = NULL;

4996 if (ret) {

4997 wpa_printf(MSG_DEBUG, "nl80211: MLME connect failed: ret=%d "

4998 "(%s)", ret, strerror(-ret));

4999 goto nla_put_failure;

5000 }

5001 ret = 0;

5002 wpa_printf(MSG_DEBUG, "nl80211: Connect request send successfully");

5003

5004nla_put_failure:

5005 nlmsg_free(msg);

5006 return ret;

5007

5008}

设置网卡工作模式 INFRA还是ADHOC的函数是nl80211_set_mode()。

5148static int nl80211_set_mode(struct wpa_driver_nl80211_data *drv,

5149 int ifindex, int mode)

5150{

5151 struct nl_msg *msg;

5152 int ret = -ENOBUFS;

5153

5154 msg = nlmsg_alloc();

5155 if (!msg)

5156 return -ENOMEM;

5157

5158 genlmsg_put(msg, 0, 0, genl_family_get_id(drv->nl80211), 0,

5159 0,NL80211_CMD_SET_INTERFACE, 0);

5160 NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);

5161 NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, mode);

5162

5163 ret = send_and_recv_msgs(drv, msg, NULL, NULL);

5164 if (!ret)

5165 return 0;

5166nla_put_failure:

5167 wpa_printf(MSG_DEBUG, "nl80211: Failed to set interface %d to mode %d:"

5168 " %d (%s)", ifindex, mode, ret, strerror(-ret));

5169 return ret;

5170}

当成功连接ibss后，

wpa_driver_nl80211_event_receive => process_event(NL80211_CMD_JOIN_IBSS) => mlme_event_join_ibss() => wpa_supplicant_event(drv->ctx,EVENT_ASSOC, NULL);

或者当INFRA时，

直接wpa_driver_nl80211_connect发送，连接成功会收到NL80211_CMD_CONNECT响应，用wpa_driver_nl80211_event_receive => process_event(NL80211_CMD_CONNECT) => mlme_event_connect=>wpa_supplicant_event(drv->ctx, EVENT_ASSOC, &event);处理。

或者当SME时， AUTH和ASSOCIATE分离，

wpa_driver_nl80211_event_receive => process_event(NL80211_CMD_ASSOCIATE) => mlme_event(NL80211_CMD_ASSOCIATE) => mlme_event_assoc () => wpa_supplicant_event(drv->ctx, EVENT_ASSOC, &event)处理。

或者当扫描时wpa_supplicant_scan() with ap_scan==0表示由driver负责AP关联；当得到kernel driver已经关联到AP后，也会wpa_supplicant_gen_assoc_event= > wpa_supplicant_event(wpa_s, EVENT_ASSOC, &data);

void wpa_supplicant_event(void *ctx, enum wpa_event_type event, union wpa_event_data *data)

case EVENT_ASSOC:

wpa_supplicant_event_assoc(wpa_s, data);

break;

EVENT_ASSOC用于表示已经关联上AP。log输出片段如下：

E/wpa_supplicant( 5668): nl80211: Event message available

E/wpa_supplicant( 5668): nl80211: cmd response received-43(NL80211_CMD_JOIN_IBSS) 46(NL80211_CMD_CONNECT) for INFRA.

E/wpa_supplicant( 5668): nl80211: enter mlme_event_join_ibss

E/wpa_supplicant( 5668): nl80211: IBSS 72:d9:d2:6d:26:d2 joined

E/wpa_supplicant( 5668): wlan0: Event 0 received on interface wlan0

E/wpa_supplicant( 5668): wlan0: ASSOC notification

D/wpa_supplicant( 5668): wpa_supplicant_event_assoc: associated to a wapi network.

D/wpa_supplicant( 5668): wlan0: State: ASSOCIATING -> ASSOCIATED

mac layer me处理层面，mlme_event调用mlme_event_mgmt处理management帧事件，其余如data、control帧使用mlme_event_xxxx系列函数处理，然后调用wpa_supplicant_event通知wpa_s。

netlink-route事件

wpa_driver_nl80211_event_rtm_newlink是在wpa_driver_nl80211_init中注册的

cfg->newlink_cb = wpa_driver_nl80211_event_rtm_newlink;

cfg->dellink_cb = wpa_driver_nl80211_event_rtm_dellink;

在driver_nl80211中，event上行路线：netlink_receive处理link事件，调用wpa_driver_nl80211_event_rtm_newlink/dellink，调用wpa_driver_nl80211_event_link处理link层面事件，调用wpa_supplicant_event通知wpa_s。

Driver

Driver config部分主要由nl80211 thin layer、linux cfg80211、vendor cfg80211部分组成，用户空间的NL80211_CMD发送给nl80211通过linux cfg80211转发或者直接发送给vendor cfg80211；vendor cfg80211控制芯片，收到操作完成的通知后，通过linux cfg80211接口经过nl80211向Multicast netlink socket发送通知给用户空间。

linux nl80211接口主要文件kernel/net/wireless/nl80211.c，向Generic Netlink注册了”nl80211” family和几个multicast group。除了nl80211，kernel/net/wireless/目录下其余文件也是linux cfg80211的实现文件，主要是core.c, scan.c, mlme.c, ibss.c, chan.c, util.c等。

vendor cfg80211 driver接口主要文件是kernel/drivers/net/wireless/bcmdhd/wl_cfg80211.c

设备注册，设备栈，rdev netdev wlan_dev sdio_func.dev mmc_card.dev

static int __init dhd_module_init(void) @ dhd_linux.c

late_initcall(dhd_module_init);

sdio_register_driver(&bcmsdh_sdmmc_driver)

sdio host controller platform device注册时会检测连接的卡设备，读出设备id，通过与bcmsdh_sdmmc_driver.id_table匹配match，然后调用bcmsdh_sdmmc_driver.probe来探测设备。大致原理见基于linux-2.6.38.8内核的SDIO/wifi驱动分析。

dhdsdio_probe一通初始化和资源分配在dhd_attach(osh, bus, SDPCM_RESERVE)中分配注册网络设备和无线设备及附加到IW。具体如下：

无线设备：wl_cfg80211_attach() allocaltes wireless_dev wdev = wl_alloc_wdev(dev);

and link it with wiphy and net_device;

wl_alloc_wdev really allocates wireless_dev using kzalloc and allocates wireless_dev.wiphy using wiphy_new(&wl_cfg80211_ops, sizeof(struct wl_priv));

and register wiphy with cfg80211 module using wiphy_register(wdev->wiphy);

网卡设备：分配ethernet网卡alloc_etherdev(sizeof(dhd))，在dhd_net_attach(dhd_pub_t *dhdp, int ifidx)中注册网卡register_netdev(net)，完成网络设备的注册，完成从总线设备到网络功能设备的注册流程。

网卡驱动帧接收具体过程从略，同普通网卡驱动。

dhd_rx_frame接收网卡收到的帧或网卡的event帧，802.11帧读出来是802.2 LLC on 802.3 or Ethernet帧的格式，event帧格式是Ethernet II frame格式，length=ETHER_TYPE_BRCM>1536，其值做为protocol type解释。802.11帧去掉Ethernet帧头将802.2 LLC帧交netif_rx继续处理解出其中的ip packet交TCPIP stack处理。Event帧则剥离ether_hdr后直接由dhd_wl_host_event()处理。

dhd_wl_host_event

=> wl_host_event处理host感兴趣的事件

=> wl_iw_event处理wext范围内事件

=> wl_cfg80211_event把cfg80211相关事件放入处理队列！

wl_event_handler线程从队列取事件并调用wl->evt_handler[e->etype] (wl, netdev, &e->emsg, e->edata)处理注册了handler的事件。事件handler是在wl_init_event_handler中注册的。

5255static void wl_init_event_handler(struct wl_priv *wl)

5256{

5257 memset(wl->evt_handler, 0, sizeof(wl->evt_handler));

5258

5259 wl->evt_handler[WLC_E_SCAN_COMPLETE] = wl_notify_scan_status;

5260 wl->evt_handler[WLC_E_LINK] = wl_notify_connect_status;

5261 wl->evt_handler[WLC_E_DEAUTH_IND] = wl_notify_connect_status;

5262 wl->evt_handler[WLC_E_DEAUTH] = wl_notify_connect_status;

5263 wl->evt_handler[WLC_E_DISASSOC_IND] = wl_notify_connect_status;

5264 wl->evt_handler[WLC_E_ASSOC_IND] = wl_notify_connect_status;

5265 wl->evt_handler[WLC_E_REASSOC_IND] = wl_notify_connect_status;

5266 wl->evt_handler[WLC_E_ROAM] = wl_notify_roaming_status;

5267 wl->evt_handler[WLC_E_MIC_ERROR] = wl_notify_mic_status;

5268 wl->evt_handler[WLC_E_SET_SSID] = wl_notify_connect_status;

5269 wl->evt_handler[WLC_E_ACTION_FRAME_RX] = wl_notify_rx_mgmt_frame;

5270 wl->evt_handler[WLC_E_PROBREQ_MSG] = wl_notify_rx_mgmt_frame;

5271 wl->evt_handler[WLC_E_P2P_PROBREQ_MSG] = wl_notify_rx_mgmt_frame;

5272 wl->evt_handler[WLC_E_P2P_DISC_LISTEN_COMPLETE] = wl_cfgp2p_listen_complete;

5273 wl->evt_handler[WLC_E_ACTION_FRAME_COMPLETE] = wl_cfgp2p_action_tx_complete;

5274 wl->evt_handler[WLC_E_ACTION_FRAME_OFF_CHAN_COMPLETE] = wl_cfgp2p_action_tx_complete;

5275

5276}

下面描述scan和join/connect在cfg80211中的处理过程

static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)

3533 request->dev = dev;

3534 request->wiphy = &rdev->wiphy;

3535 request->no_cck =

3536 nla_get_flag(info->attrs[NL80211_ATTR_TX_NO_CCK_RATE]);

3537

3538 rdev->scan_req = request;

3539 err = rdev->ops->scan(&rdev->wiphy, dev, request);

ops scan field is wl_cfg80211_scan(), it calls

=> __wl_cfg80211_scan()

=> wl_do_escan() when e-scanner is used

=> wl_run_escan()向sdio接口发送命令

当芯片扫描完成后，发出WLC_E_SCAN_COMPLETE事件；驱动WLC_GET_SCAN_RESULTS，芯片返回WLC_E_SCAN_RESULTS事件？wl_escan_handler is called，这个是在wl_init_scan()中使用e-scanner时注册的，wl->evt_handler[WLC_E_ESCAN_RESULT] = wl_escan_handler;

scan results内核数据更新

wl_escan_handler中对扫描到的每个报告帧解析，添加到内核网卡数据结构bss_list中；

wl_escan_handler => wl_inform_bss => wl_inform_single_bss

连接成功AP后，也会更新该数据结构。

wl_bss_connect_done => wl_update_bss_info(not ibss) => wl_inform_single_bss

以后wl_inform_single_bss => cfg80211_inform_bss_frame => cfg80211_bss_update操作rb tree.

还有一条线 cfg80211_inform_bss => cfg80211_bss_update此条线能找到

wl_ibss_join_done => wl_update_ibss_info(ibss) => wl_inform_single_bss

NL80211_CMD_SET_INTERFACE command to kernel space driver =>

static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)

1586 if (change)

1587 err =cfg80211_change_iface(rdev, dev, ntype, flags, &params);

int cfg80211_change_iface(…)

846 err = rdev->ops->change_virtual_intf(&rdev->wiphy, dev,

847 ntype, flags, params);

change_virtual_intf is wl_cfg80211_change_virtual_iface() for bcmdhd driver.在

wl_cfg80211在wl_cfg80211_change_virtual_iface()中设置到IBSS模式时没有执行，需要patch上WLC_SET_INFRA.

err = wldev_ioctl(ndev, WLC_SET_INFRA, &infra, sizeof(infra), true);

另外地，wldev_ioctl(ndev, WLC_SET_INFRA, &infra, sizeof(infra), true)在wl_config_ifmode中也被调用，而wl_config_ifmode在wl_cfg80211_up(void *para)=>__wl_cfg80211_up中被调用。

wl_cfg80211_up只在dhd驱动的open函数dhd_open(struct net_device *net)中使用一次，用于网卡打开进行配置使用，所以iwconfig可以使能网卡IBSS模式，但是wpa_supplicant不能使能网卡IBSS模式的原因大概在此。

static s32 wl_config_ifmode(struct wl_priv *wl, struct net_device *ndev, s32 iftype)

{

s32 infra = 0;

s32 err = 0;

s32 mode = 0;

switch (iftype) {

case NL80211_IFTYPE_MONITOR:

case NL80211_IFTYPE_WDS:

WL_ERR(("type (%d) : currently we do not support this mode\n",

iftype));

err = -EINVAL;

return err;

case NL80211_IFTYPE_ADHOC:

mode = WL_MODE_IBSS;

break;

case NL80211_IFTYPE_STATION:

case NL80211_IFTYPE_P2P_CLIENT:

mode = WL_MODE_BSS;

infra = 1;

break;

case NL80211_IFTYPE_AP:

case NL80211_IFTYPE_P2P_GO:

mode = WL_MODE_AP;

infra = 1;

break;

default:

err = -EINVAL;

WL_ERR(("invalid type (%d)\n", iftype));

return err;

}

infra = htod32(infra);

err = wldev_ioctl(ndev, WLC_SET_INFRA, &infra, sizeof(infra), true);

if (unlikely(err)) {

WL_ERR(("WLC_SET_INFRA error (%d)\n", err));

return err;

}

wl_set_mode_by_netdev(wl, ndev, mode);

return 0;

}

再看第二个步骤发送JOIN_IBSS for IBSS mode, or CONNECT for INFRA mode。

join_ibss in driver_nl80211.c

wpa_driver_nl80211_ibss

genlmsg_put(msg, 0, 0, genl_family_get_id(drv->nl80211), 0, 0,

NL80211_CMD_JOIN_IBSS, 0);

NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, drv->ifindex);

kernel/net/wireless/nl80211.c is one driver top file for JOIN_IBSS。

4330static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)

4331{

4332 struct cfg80211_registered_device *rdev = info->user_ptr[0];

4333 struct net_device *dev = info->user_ptr[1];

4334 struct cfg80211_ibss_params ibss;

4335 struct wiphy *wiphy;

4336 struct cfg80211_cached_keys *connkeys = NULL;

4337 int err;

4338

4339 memset(&ibss, 0, sizeof(ibss));

4340

4341 if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))

4342 return -EINVAL;

4343

4344 if (!info->attrs[NL80211_ATTR_WIPHY_FREQ] ||

4345 !info->attrs[NL80211_ATTR_SSID] ||

4346 !nla_len(info->attrs[NL80211_ATTR_SSID]))

4347 return -EINVAL;

4348

4349 ibss.beacon_interval = 100;

4350

4351 if (info->attrs[NL80211_ATTR_BEACON_INTERVAL]) {

4352 ibss.beacon_interval =

4353 nla_get_u32(info->attrs[NL80211_ATTR_BEACON_INTERVAL]);

4354 if (ibss.beacon_interval < 1 || ibss.beacon_interval > 10000)

4355 return -EINVAL;

4356 }

4357

4358 if (!rdev->ops->join_ibss)

4359 return -EOPNOTSUPP;

4360

4361 if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_ADHOC)

4362 return -EOPNOTSUPP; //这个东西并不影响IBSS逻辑，奇怪？

4363

4364 wiphy = &rdev->wiphy;

4365

4366 if (info->attrs[NL80211_ATTR_MAC])

4367 ibss.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);

4368 ibss.ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);

4369 ibss.ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);

4370

4371 if (info->attrs[NL80211_ATTR_IE]) {

4372 ibss.ie = nla_data(info->attrs[NL80211_ATTR_IE]);

4373 ibss.ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);

4374 }

4375

4376 ibss.channel = ieee80211_get_channel(wiphy,

4377 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]));

4378 if (!ibss.channel ||

4379 ibss.channel->flags & IEEE80211_CHAN_NO_IBSS ||

4380 ibss.channel->flags & IEEE80211_CHAN_DISABLED)

4381 return -EINVAL;

4382

4383 ibss.channel_fixed = !!info->attrs[NL80211_ATTR_FREQ_FIXED];

4384 ibss.privacy = !!info->attrs[NL80211_ATTR_PRIVACY];

4385

4386 if (info->attrs[NL80211_ATTR_BSS_BASIC_RATES]) {

4387 u8 *rates =

4388 nla_data(info->attrs[NL80211_ATTR_BSS_BASIC_RATES]);

4389 int n_rates =

4390 nla_len(info->attrs[NL80211_ATTR_BSS_BASIC_RATES]);

4391 struct ieee80211_supported_band *sband =

4392 wiphy->bands[ibss.channel->band];

4393 int err;

4394 err = ieee80211_get_ratemask(sband, rates, n_rates,

4395 &ibss.basic_rates);

4396 if (err)

4397 return err;

4398 }

4399

4400 if (info->attrs[NL80211_ATTR_MCAST_RATE] &&

4401 !nl80211_parse_mcast_rate(rdev, ibss.mcast_rate,

4402 nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE])))

4403 return -EINVAL;

4404

4405 if (ibss.privacy && info->attrs[NL80211_ATTR_KEYS]) {

4406 connkeys = nl80211_parse_connkeys(rdev,

4407 info->attrs[NL80211_ATTR_KEYS]);

4408 if (IS_ERR(connkeys))

4409 return PTR_ERR(connkeys);

4410 }

4411

4412 err = cfg80211_join_ibss(rdev, dev, &ibss, connkeys);

4413 if (err)

4414 kfree(connkeys);

4415 return err;

4416}

In wl_cfg80211.c

1758static s32

1759wl_cfg80211_join_ibss(struct wiphy *wiphy, struct net_device *dev,

1760 struct cfg80211_ibss_params *params)

1761{

1762 struct wl_priv *wl = wiphy_priv(wiphy);

1763 struct cfg80211_bss *bss;

1764 struct ieee80211_channel *chan;

1765 struct wl_join_params join_params;

1766 struct cfg80211_ssid ssid;

1767 s32 scan_retry = 0;

1768 s32 err = 0;

1769 bool rollback_lock = false;

1770

1771 WL_TRACE(("In\n"));

1772 CHECK_SYS_UP(wl);

1773 if (params->bssid) { // remove the ibss-blocking code

1774 WL_ERR(("Invalid bssid\n"));

1775 return -EOPNOTSUPP;

1776 }

1777 bss = cfg80211_get_ibss(wiphy, NULL, params->ssid, params->ssid_len);

1778 if (!bss) {

1779 memcpy(ssid.ssid, params->ssid, params->ssid_len);

1780 ssid.ssid_len = params->ssid_len;

1781 do {

1782 if (unlikely

1783 (__wl_cfg80211_scan(wiphy, dev, NULL, &ssid) ==

1784 -EBUSY)) {

1785 wl_delay(150);

1786 } else {

1787 break;

1788 }

1789 } while (++scan_retry < WL_SCAN_RETRY_MAX);

1790 /* to allow scan_inform to propagate to cfg80211 plane */

1791 if (rtnl_is_locked()) {

1792 rtnl_unlock();

1793 rollback_lock = true;

1794 }

1795

1796 /* wait 4 secons till scan done.... */

1797 schedule_timeout_interruptible(4 * HZ);

1798 if (rollback_lock)

1799 rtnl_lock();

1800 bss = cfg80211_get_ibss(wiphy, NULL,

1801 params->ssid, params->ssid_len);

1802 }

1803 if (bss) {

1804 wl->ibss_starter = false;

1805 WL_DBG(("Found IBSS\n"));

1806 } else {

1807 wl->ibss_starter = true;

1808 }

1809 chan = params->channel;

1810 if (chan)

1811 wl->channel = ieee80211_frequency_to_channel(chan->center_freq);

1812 /*

1813 * Join with specific BSSID and cached SSID

1814 * If SSID is zero join based on BSSID only

1815 */

1816 memset(&join_params, 0, sizeof(join_params));

1817 memcpy((void *)join_params.ssid.SSID, (void *)params->ssid,

1818 params->ssid_len);

1819 join_params.ssid.SSID_len = htod32(params->ssid_len);

1820 if (params->bssid)

1821 memcpy(&join_params.params.bssid, params->bssid,

1822 ETHER_ADDR_LEN);

1823 else

1824 memset(&join_params.params.bssid, 0, ETHER_ADDR_LEN);

1825

1826 err = wldev_ioctl(dev, WLC_SET_SSID, &join_params,

1827 sizeof(join_params), false);

1828 if (unlikely(err)) {

1829 WL_ERR(("Error (%d)\n", err));

1830 return err;

1831 }

1832 return err;

1833}

发送给dhd固件，err是0，表发送成功；

WLC_SET_SSID的结果以异步形式由固件发送回来。此时收到的WLC_E_SET_SSID的status是WLC_E_STATUS_NO_NETWORKS。

设置WLC_SET_INFRA后，修改join_ibss相关代码，可以收到WLC_E_SET_SSID with status WLC_E_STATUS_SUCCESSFUL,连接上IBSS。

驱动中在关联AP成功时收到的主要是WLC_E_LINK、WLC_E_JOIN和WLC_E_SET_SSID，会通过event_handler处理或通知wpa_supplicant。其实只有收到WLC_E_JOIN事件时才表示真正join ibss或connect成功。

SME & MLME & PLME

Userspace SME uses kernel providing MLME to do mac layer management.

END

http://blog.csdn.net/zirconsdu/article/details/8569193

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