[RK3288][Android6.0] WiFi之Framework扫描过程

来源：互联网发布：科来抓包软件破解版编辑：程序博客网时间：2024/05/10 16:37

Platform: Rockchip
OS: Android 6.0
Kernel: 3.10.92

Settings去开启wifi时，会调用到DisconnectedState类

enter -> WifiStateMachine.java//DisconnectedState
startScan ->
   sendMessage -> //cmd:CMD_START_SCAN
      processMessage -> //DisconnectedState类，返回NOT_HANDLED,让父类处理
        processMessage -> //ConnectModeState类，返回NOT_HANDLED,让父类处理
       processMessage -> //DriverStartedState类
          handleScanRequest -> //cmd: SCAN_WITHOUT_CONNECTION_SETUP
           startScanNative ->
              mWifiNative.scan ->
               scan -> WifiNative.java
                  doBooleanCommand   -> //command会根据type及freq list决定发的命令，这里是"SCAN TYPE=ONLY"
                   wpa_supplicant_ctrl_iface_receive -> ctrl_iface_unix.c
                      wpa_supplicant_ctrl_iface_process -> //cmd: scan
                       wpas_ctrl_scan ->
                          can_res_handler = scan_only_handler   //设置type=only才会跑的handler
                           wpa_supplicant_req_scan //发起扫描请求

调用返回成功只表示发送扫描请求被接受，而扫描完成后会发送完成事件给framework，framework通过WifiMonitor类负责监听事件接收。
_wpa_supplicant_event_scan_results -> events.c
wpa_msg_ctrl -> //event: WPA_EVENT_SCAN_RESULTS
    run -> WifiMonitor.java
      mWifiNative.waitForEvent //等到event后返回往下运行
        mWifiMonitorSingleton.dispatchEvent ->
          m.dispatchEvent ->
            handleEvent ->
              mStateMachine.sendMessage -> //event: SCAN_RESULTS_EVENT
                processMessage -> //DisconnectedState
                  processMessage -> //ConnectModeState
                    processMessage -> //DriverStartedState
                      processMessage -> //SupplicantStartedState
                        setScanResults -> //从native获取并保存扫描结果
                          mWifiNative.scanResults ->
                            doStringCommandWithoutLogging("BSS RANGE=" + sid + "- MASK=0x29d87");
                        sendScanResultsAvailableBroadcast   //通知app扫描完成，intent是WifiManager.SCAN_RESULTS_AVAILABLE_ACTION

设置了WifiManager.SCAN_RESULTS_AVAILABLE_ACTION的app就能收到消息，可以通过接口getScanResults()来获取，比如Settings apk利用它来更新扫描列表。

扫描返回结果的格式如下：
* =================
* id=1
* bssid=68:7f:74:d7:1b:6e
* freq=2412
* level=-43
* tsf=1344621975160944
* age=2623
* flags=[WPA2-PSK-CCMP][WPS][ESS]
* ssid=zubyb
* ====


参考：
Android -- Wifi扫描流程分析

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