Implementation of WLAN on Android

As we all know, Android is based on the Linux kernel, so it directly supports the Linux WLAN interface. The kernel driver of WLAN is dynamically loaded based on user settings on the UI. the control and security of WLAN are achieved through ctrl_interface and openssl, and TCPIP is implemented based on WLAN standards.

The architecture of WLAN on Android is as follows:

Application Framework: base/wifi/java/android/net/wifi

WifiManager/WifiMonitor/WifiConfiguration...

Service Framework: base/services/java/com/android/server/

WifiService/WifiWatchdogService

JNI (Java Native Interface)

Jni/android_net_wifi_Wifi.cpp

HAL (Hardware Abstract Layer)

Hardware/libhardware/wifi. c

Wpa_supplicant/ctrl_interface

Kernel driver

The process for enabling WIFI on an Android phone is as follows:

1) Application Framework: WifiManager

SetWifiEnabled ()

2) Service: WifiService

SetWifiEnabled ()

HandleMessage (): MESSAGE_ENABLE_WIFI

3) JNI: android_net_wifi_Wifi.cpp:

JNINativeMethod: loadDriver

Android_net_wifi_loadDriver ()

4) HAL: hardware/libhardware/wifi. c

Wifi_load_driver ()

5) Kernel: load the Kernel driver

 

The WLAN search process is as follows:

1) Application Framework: WifiManager

StartScan ()

2) Service:

WifiService: startScan ()

WifiNative: scanCommand ();

3) JNI: android_net_wifi_Wifi.cpp:

JNINativeMethod: scanCommand/scanResultsCommand

Android_net_wifi_scanCommand/android_net_wifi_scanResultsCommand

4) HAL: hardware/libhardware/wifi. c

Wifi_send_command: SCAN/SCAN_RESULTS

Wpa_supplicant/driver_wext.c

Wpa_driver_wext_scan (): SIOCSIWSCAN

5) Kernel: Command for WLAN driver to process related interfaces

WAPI is the national standard for WLAN in China-GB 15629.11, and is compatible with 802.11i. To implement WAPI on Android, you only need to add corresponding authentication.