【轉載】Android WiFi 架構總覽（模塊及接口）
原文地址：https://blog.csdn.net/xusiwei1236/article/details/48495485java
Android WiFi 架構總覽
本文介紹Android源碼項目（AOSP）中WiFi功能的軟件架構及各個模塊（可執行文件、動態連接庫）間的接口。linux
SDK API
Android SDK爲開發者提供了WiFi編程接口，使用起來很是方便。android
相關包： android.net.wifi（寫App時只需import該包，便可使用WiFi相關功能)編程
主要相關類:
* WifiManager WIFI編程入口，WIFI的多數功能都以該類的方法的形式提供
* WifiInfo 用於描述WIFI鏈接的狀態
* ScanResult 用於描述一個AP，如SSID，信號強度，安全方式等api
Overview
下圖基展現了Android系統WIFI模塊的架構（固然，這只是軟件的控制命令部分，數據部分直接經過kernel與網絡子系統、socket API交互）。 
（PS：一圖勝千言，雖然用ppt畫起來費勁）
WifiManager是管理全部Wifi鏈接的基本API，能夠經過： android.content.Context.getSystemService(Context.WIFI_SERVICE)
獲得它的實例。數組
具體 IPC(Inter-Process communication)
App & system_server(WifiManager & WifiService)
若是說Binder是鏈接 App 和 system_server 的橋樑，那麼WifiManager和WiFiService就是橋樑的兩頭。安全
framework代碼上和wifi相關的package位於: frameworks/base/wifi/java(WIFI相關的一些包) frameworks/base/services/java(各類Service,WIFI相關包爲：com.android.server.wifi)網絡
frameworks代碼中，和wifi相關的幾個類的關係以下：多線程
- WifiService繼承自IWifiManager.Stub；
- IWifiManager.Stub又繼承自Binder，同時實現了IWifiManager接口;
- WifiManager.Stu.proxy也實現了IWifiManager接口；
如圖： 架構
其中，IWifiManager, IWifiManager.Stub, IWifiManager.Stub.Proxy都由IWifiManger.aidl生成；
aidl自動生成相關的java代碼，簡化了用Binder實現RPC的過程。
IWifiManager.Stub.Proxy，WifiManager，BinberProxy用於客戶端（App進程）；
而IWifiManager.Stub，WifiService，Binder用於服務端（SystemServer進程）。
App 與 system_server 經過Binder通訊，但Binder自己只實現了IPC，即相似socket通訊的能力。而App端的WifiManager和system_server端的WifiService及Binder等類共同實現了RPC(remote procedure call)。
WifiManager只是系統爲app提供的接口。Context.getSystemService(Context.WIFI_SERVICE)
返回的實際對象類型是IWifiManager.Stub.Proxy。 IWifiManager.Stub.Proxy的實例是位於App端的一個代理，代理象IWifiManager.Stub.Proxy
將WifiManager方法的參數序列化到Parcel，再經Binder發送給system_server進程。
system_server內的WifiService收App傳來的WifiManager調用，完成實際工做。
這樣，實際和下層通訊的工做就由App轉移到了system_server進程（WifiService對象）。
WifiStateMachine
另外，能夠看到 WifiStateMachine 是wifi功能的樞紐，幾種不一樣模式下的控制流程都經它流下。
當WIFI處在STA模式（或P2P模式）時，經過WifiNative與wpa_supplicant交互。
WifiNative定義了幾個Native方法：
1 public native static boolean setMaxTxPower(int txpower, boolean sapRunning); 2 3 public native static boolean loadDriver(); 4 5 public native static boolean isDriverLoaded(); 6 7 public native static boolean unloadDriver(); 8 9 public native static boolean startSupplicant(boolean p2pSupported, int firstScanDelay); 10 11 /* Sends a kill signal to supplicant. To be used when we have lost connection 12 or when the supplicant is hung */ 13 public native static boolean killSupplicant(boolean p2pSupported); 14 15 private native boolean connectToSupplicantNative(); 16 17 private native void closeSupplicantConnectionNative(); 18 19 /** 20 * Wait for the supplicant to send an event, returning the event string. 21 * @return the event string sent by the supplicant. 22 */ 23 private native String waitForEventNative(); 24 25 private native boolean doBooleanCommandNative(String command); 26 27 private native int doIntCommandNative(String command); 28 29 private native String doStringCommandNative(String command);
當WIFI處在AP模式。經過NetworkManagementService與netd交互，具體是經過LocalSocket(Framework封裝的UNIX域socket)與netd進程通訊。
好比，NetworkManagementService.startAccessPoint方法：
1 @Override 2 public void startAccessPoint( 3 WifiConfiguration wifiConfig, String wlanIface) { 4 mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG); 5 try { 6 wifiFirmwareReload(wlanIface, "AP"); 7 if (wifiConfig == null) { 8 mConnector.execute("softap", "set", wlanIface); // 向 netd 發送控制命令 9 } else { 10 mConnector.execute("softap", "set", wlanIface, wifiConfig.SSID, 11 wifiConfig.hiddenSSID ? "hidden" : "broadcast", 12 "1", getSecurityType(wifiConfig), 13 new SensitiveArg(wifiConfig.preSharedKey)); 14 } 15 mConnector.execute("softap", "startap"); 16 } catch (NativeDaemonConnectorException e) { 17 throw e.rethrowAsParcelableException(); 18 } 19 }
WifiNative
從功能上來講，WifiNative是system_server 和 wpa_supplicant 對話的窗口，實際上主要依靠wpa_supplicant項目編譯出來的動態庫libwpa_client.so。
WifiNative的幾個native方法的具體實如今： frameworks/base/core/jni/android_net_wifi_WifiNative.cpp
WifiNative的native方法的實現：
1 static JNINativeMethod gWifiMethods[] = { 2 /* name, signature, funcPtr */ 3 { "loadDriver", "()Z", (void *)android_net_wifi_loadDriver }, 4 { "isDriverLoaded", "()Z", (void *)android_net_wifi_isDriverLoaded }, 5 { "unloadDriver", "()Z", (void *)android_net_wifi_unloadDriver }, 6 { "startSupplicant", "(ZI)Z", (void *)android_net_wifi_startSupplicant }, 7 { "killSupplicant", "(Z)Z", (void *)android_net_wifi_killSupplicant }, 8 { "connectToSupplicantNative", "()Z", (void *)android_net_wifi_connectToSupplicant }, 9 { "closeSupplicantConnectionNative", "()V", (void *)android_net_wifi_closeSupplicantConnection }, 10 { "waitForEventNative", "()Ljava/lang/String;", (void*)android_net_wifi_waitForEvent }, 11 { "doBooleanCommandNative", "(Ljava/lang/String;)Z", (void*)android_net_wifi_doBooleanCommand }, 12 { "doIntCommandNative", "(Ljava/lang/String;)I", (void*)android_net_wifi_doIntCommand }, 13 { "doStringCommandNative", "(Ljava/lang/String;)Ljava/lang/String;", (void*) android_net_wifi_doStringCommand }, 14 { "setMaxTxPower", "(IZ)Z", (void *)android_net_wifi_setMaxTxPower }, 15 };
android_net_wifi_WifiNative.cpp 並無作多少實際工做，大可能是直接調用 wifi.h wifi_maxtxpower.h 定義的函數:
wifi.h 的具體實如今 hardware/libhardware_legacy/wifi/wifi.c (會被編譯爲 libhardware_legacy.so)
wifi_maxtxpower.h 的具體實如今 hardware/qcom/wlan/libmaxtxpower/wifi_maxtxpower.c (會被編譯爲 libmaxtxpower.so)
因此native代碼依賴libhardware_legacy.so模塊、libmaxtxpower.so模塊。
WIFI HAL
實現SystemServer與wpa_supplicant(hostapd)通訊的，即Wifi HAL。
Wifi HAL封裝了UNIX域socket，SystemServer經過UNIX域socket與wpa_supplicant(hostapd)
通訊；SystemServer發送的消息和wpa_supplicant響應的消息都是爲ASCII字符串。
Wifi HAL代碼主要分佈在： hardware/libhardware_legacy/wifi hardware/qcom/wlan/libmaxtxpower
分別被編譯爲： hardware/libhardware_legacy/wifi -> libhardware_legacy.so hardware/qcom/wlan/libmaxtxpower -> libmaxtxpower.so
wifi.h定義了WIFI HAL的接口，具體函數有：
1 // 驅動相關: 2 int wifi_load_driver(); 3 int wifi_unload_driver(); 4 int is_wifi_driver_loaded(); 5 6 // supplicant相關: 7 int wifi_start_supplicant(int p2pSupported, int first_scan_delay); 8 int wifi_stop_supplicant(int p2pSupported); 9 int wifi_connect_to_supplicant(); 10 void wifi_close_supplicant_connection(); 11 12 // 等待WIFI事發生，該函數會阻塞當前調用，直到有wifi事件發生時，返回一個表示wifi事件的字符 13 int wifi_wait_for_event(char *buf, size_t len); 14 15 // 向wifi驅動發一個命，（多數功能經該函數向下層發命令） 16 int wifi_command(const char *command, char *reply, size_t *reply_len); 17 18 // 發起一dhcp請求 19 int do_dhcp_request(int *ipaddr, int *gateway, int *mask, 20 int *dns1, int *dns2, int *server, int *lease); 21 22 // 返回一個do_dhcp_request()的錯誤字符串 23 const char *get_dhcp_error_string(); 24 25 #define WIFI_GET_FW_PATH_STA 0 26 #define WIFI_GET_FW_PATH_AP 1 27 #define WIFI_GET_FW_PATH_P2P 2 28 29 // 返一個請的firmware路徑 30 const char *wifi_get_fw_path(int fw_type); 31 32 // 爲wlan驅動改變firmware路徑 33 int wifi_change_fw_path(const char *fwpath); 34 35 #define WIFI_ENTROPY_FILE "/data/misc/wifi/entropy.bin" 36 37 int ensure_entropy_file_exists();
wifi_maxtxpower.h 只定義了一個函數：
int set_max_tx_power(int power, int sap_running);
- 1
android_net_wifi_WifiNative.cpp 調用了這些函數。
wifi.c調用了wpa_ctrl.h定義的一些函數，而wpa_ctrl.h中的函數
在external/wpa_supplicant_8 項目實現，並被編譯爲libwpa_client.so，
詳見external/wpa_supplicant_8/Android.mk。
wpa_supplicant(hostapd)
代碼位於： external/wpa_supplicant_8
該項目內包含兩個互相相關的開源項目wpa_supplicant和hostapd，它們將會生成兩個可執行文件：
wpa_supplicant和hostapd，分別爲STA模式和AP模式時的守護進程。
除此以外，還會生成用於測試的wpa_cli，hostapd_cli，
以及WIFI HAL依賴的wpa_client.so，具體能夠到Android.mk中找到。
wpa_supplicant源碼結構和hostapd相似，下面只介紹wpa_supplicant。
wpa_ctrl.h 定義了與wpa_supplicant(或hostapd)進程通訊的接口：
1 struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path); 2 3 // Close a control interface to wpa_supplicant/hostapd 4 void wpa_ctrl_close(struct wpa_ctrl *ctrl); 5 6 // Send a command to wpa_supplicant/hostapd 7 int wpa_ctrl_request(struct wpa_ctrl *ctrl, const char *cmd, size_t cmd_len, 8 char *reply, size_t *reply_len, 9 void (*msg_cb)(char *msg, size_t len)); 10 11 // Register as an event monitor for the control interface 12 int wpa_ctrl_attach(struct wpa_ctrl *ctrl); 13 14 // Unregister event monitor from the control interface 15 int wpa_ctrl_detach(struct wpa_ctrl *ctrl); 16 17 // Receive a pending control interface message 18 int wpa_ctrl_recv(struct wpa_ctrl *ctrl, char *reply, size_t *reply_len); 19 20 // Check whether there are pending event messages 21 int wpa_ctrl_pending(struct wpa_ctrl *ctrl); 22 23 // Get file descriptor used by the control interface 24 int wpa_ctrl_get_fd(struct wpa_ctrl *ctrl); 25 26 char * wpa_ctrl_get_remote_ifname(struct wpa_ctrl *ctrl);
wpa_ctrl_open 建立一個UNIX域socket 與 wpa_supplicant(或hostapd)進程相連，
wpa_ctrl_close 用於關閉wpa_ctrl_open建立的鏈接，
wpa_ctrl_request 用於向wpa_supplicant/hostapd發送控制命令，並阻塞，
直到wpa_supplicant/hostapd返回命令響應。控制命令和相應都是ASCII字符串。
wpa_ctrl.h除了聲明瞭這些函數外，還定義了wpa_supplicant/hostapd的一些消息，這裏沒有詳細列出。
源碼中wpa_supplicant_global_ctrl_iface_receive
負責分派上層發來的控制命令，進而調用具體處理函數：
1 "ATTACH" -> wpa_supplicant_ctrl_iface_attach 2 "DETACH" -> wpa_supplicant_ctrl_iface_detach 3 else -> wpa_supplicant_global_ctrl_iface_process: 4 "IFNAME="(prefix) // 多數控制命令以IFNAME=開頭 5 -> wpas_global_ctrl_iface_ifname 6 -> wpa_supplicant_ctrl_iface_process # "IFNAME="開頭的命令的處理 7 wpas_global_ctrl_iface_redir 8 -> wpas_global_ctrl_iface_redir_p2p 9 -> wpa_supplicant_ctrl_iface_process # "IFNAME="開頭的命令的處理 10 -> wpas_global_ctrl_iface_redir_wfd 11 -> wpa_supplicant_ctrl_iface_process # "IFNAME="開頭的命令的處理 12 "PING" -> "PONG" 13 "INTERFACE_ADD" -> wpa_supplicant_global_iface_add 14 "INTERFACE_REMOVE" -> wpa_supplicant_global_iface_remove 15 "INTERFACE_LIST" -> wpa_supplicant_global_iface_list 16 "INTERFACES" -> wpa_supplicant_global_iface_interfaces 17 "TERMINATE" -> wpa_supplicant_terminate_proc 18 "SUSPEND" -> wpas_notify_suspend 19 "RESUME" -> wpas_notify_resume 20 "SET" -> wpas_global_ctrl_iface_set 21 "SAVE_CONFIG" -> wpas_global_ctrl_iface_save_config 22 "STATUS" -> wpas_global_ctrl_iface_status
該函數在wpa_supplicant目錄下的 ctrl_iface_unix.c和ctrl_iface_udp.c內都有實現，可由該目錄下的android.config切換
（android.config被Android.mk包含，具體參見Android.mk）
wpa_supplicant與內核通訊
wpa_supplicant的運行模型是單進程單線程的 Reactor(IO multiplexing)。wpa_supplicant經過NETLINK socket與內核通訊。
wpa_supplicant項目支持多種驅動編程接口，在Android上使用的是nl80211;
nl80211是新的802.11netlink接口公共頭，與cfg80211一同組成了Wireless-Extensions的替代方案。
cfg80211是Linux 802.11配置API, nl80211用於配置cfg80211設備，同時用於內核到用戶空間的通訊。
實際使用nl80211時，只須要在程序中包含頭文件
wireless module(in kernel)
代碼位於: kernel/net/wireless
nl80211.c 中的 nl80211_init 使用genl_register_family_with_ops 註冊了響應應用程序的 struct genl_ops nl80211_ops[], 該數組定義了響應NETLINK消息的函數。
而 nl80211_init 在 cfg80211_init 內被調用，cfg80211_init是被subsys_initcall註冊的
子系統初始化程序，被編譯爲cfg80211.ko。
nl80211_ops[] 節選：
1 static struct genl_ops nl80211_ops[] = { 2 // ... 3 { 4 .cmd = NL80211_CMD_TRIGGER_SCAN, 5 .doit = nl80211_trigger_scan, 6 .policy = nl80211_policy, 7 .flags = GENL_ADMIN_PERM, 8 .internal_flags = NL80211_FLAG_NEED_NETDEV_UP | 9 NL80211_FLAG_NEED_RTNL, 10 }, 11 { 12 .cmd = NL80211_CMD_GET_SCAN, 13 .policy = nl80211_policy, 14 .dumpit = nl80211_dump_scan, 15 }, 16 { 17 .cmd = NL80211_CMD_START_SCHED_SCAN, 18 .doit = nl80211_start_sched_scan, 19 .policy = nl80211_policy, 20 .flags = GENL_ADMIN_PERM, 21 .internal_flags = NL80211_FLAG_NEED_NETDEV_UP | 22 NL80211_FLAG_NEED_RTNL, 23 }, 24 { 25 .cmd = NL80211_CMD_STOP_SCHED_SCAN, 26 .doit = nl80211_stop_sched_scan, 27 .policy = nl80211_policy, 28 .flags = GENL_ADMIN_PERM, 29 .internal_flags = NL80211_FLAG_NEED_NETDEV_UP | 30 NL80211_FLAG_NEED_RTNL, 31 }, 32 33 // ... 34 };
wlan driver
代碼位於： vendor/qcom/opensource/wlan/prima
模塊初始化(module_init)，模塊退出(module_exit)：
CORE/HDD/src/wlan_hdd_main.c
模型：
多線程 + 隊列
建立內核線程： CORE/VOSS/src/vos_sched.c 的 vos_sched_open()
線程任務(vos_sched.c)：
* VosMcThread() - The VOSS Main Controller thread
* VosWdThread() - The VOSS Watchdog thread
* VosTXThread() - The VOSS Main Tx thread
* VosRXThread() - The VOSS Main Rx thread
線程環境(context) (vos_sched.h)：
1 typedef struct _VosSchedContext 2 { 3 /* Place holder to the VOSS Context */ 4 v_PVOID_t pVContext; 5 6 /* WDA Message queue on the Main thread*/ 7 VosMqType wdaMcMq; 8 9 /* PE Message queue on the Main thread*/ 10 VosMqType peMcMq; 11 12 /* SME Message queue on the Main thread*/ 13 VosMqType smeMcMq; 14 15 /* TL Message queue on the Main thread */ 16 VosMqType tlMcMq; 17 18 /* SYS Message queue on the Main thread */ 19 VosMqType sysMcMq; 20 21 /* WDI Message queue on the Main thread*/ 22 VosMqType wdiMcMq; 23 24 /* WDI Message queue on the Tx Thread*/ 25 VosMqType wdiTxMq; 26 27 /* WDI Message queue on the Rx Thread*/ 28 VosMqType wdiRxMq; 29 30 /* TL Message queue on the Tx thread */ 31 VosMqType tlTxMq; 32 33 /* TL Message queue on the Rx thread */ 34 VosMqType tlRxMq; 35 36 /* SYS Message queue on the Tx thread */ 37 VosMqType sysTxMq; 38 39 VosMqType sysRxMq; 40 41 // ... 42 43 struct task_struct* McThread; 44 45 /* TX Thread handle */ 46 47 struct task_struct* TxThread; 48 49 /* RX Thread handle */ 50 struct task_struct* RxThread; 51 52 // ... 53 } VosSchedContext, *pVosSchedContext;
高通資料：
80-Y0513-1_G_QCA_WCN36x0_Software_Architecture.pdf
chapter: Android WLAN Host Software Architecture
SCAN過程跟蹤
App
1 WifiManager wifiManager = (WifiManager)Context.getService(Contex.WIFI_SERVICE); 2 wifiManager.startScan(); 3 4 //wifiManager --> IWifiManager.Stub.Proxy 5 6 IWifiManager.Stub.Proxy implements android.net.wifi.IWifiManager 7 8 wifiManager.startScan() 9 -> IWifiManager.Stub.Proxy.startScan(WorkSource=null); 10 -> BinderProxy.transact(Stub.TRANSACTION_startScan, _data, _reply, 0);
systerm_server
wifi –> WifiService
1 WifiService extends IWifiManager.Stub 2 3 IWifiManager.Stub extends android.os.Binder 4 implements android.net.wifi.IWifiManager 5 6 -> IWifiManager.Stub.onTransact(int code, Parcel data, Parcel reply, int flags); 7 case TRANSACTION_startScan: 8 -> WifiService.startScan(WorkSource workSource); 9 -> WifiStateMachine.startScan(int callingUid, WorkSource workSource); 10 -> StateMachine.sendMessage(CMD_START_SCAN, callingUid, 0, workSource); 11 case CMD_START_SCAN: 12 -> handleScanRequest(WifiNative.SCAN_WITHOUT_CONNECTION_SETUP, message); 13 -> startScanNative(type, freqs) 14 -> WifiNative.scan(type, freqs) 15 -> doBooleanCommand("SCAN ..."); // AF_UNIX socket, send to wpa_supplicant
wpa_supplicant
1 external/wpa_supplicant_8/wpa_supplicant$ grep -nr "\"SCAN " . 2 ./ChangeLog:197: - "SCAN freq=<freq list>" can be used to specify which channels are 3 ./ChangeLog:199: - "SCAN passive=1" can be used to request a passive scan (no Probe 4 ./ChangeLog:201: - "SCAN use_id" can be used to request a scan id to be returned and 5 ./ChangeLog:203: - "SCAN only_new=1" can be used to request the driver/cfg80211 to 6 ./ctrl_iface.c:6986: } else if (os_strncmp(buf, "SCAN ", 5) == 0) { 7 ./src/drivers/driver_test.c:1289: ret = os_snprintf(pos, end - pos, "SCAN " MACSTR, 8 ./src/drivers/driver_test.c:1994: } else if (os_strncmp(buf, "SCAN ", 5) == 0) { 9 ./ctrl_iface.c:6986: } else if (os_strncmp(buf, "SCAN ", 5) == 0) {
refer to ./ctrl_iface.c:6986
1 } else if (os_strcmp(buf, "SCAN") == 0) { 2 wpas_ctrl_scan(wpa_s, NULL, reply, reply_size, &reply_len); 3 } else if (os_strncmp(buf, "SCAN ", 5) == 0) { 4 wpas_ctrl_scan(wpa_s, buf + 5, reply, reply_size, &reply_len);
wpas_ctrl_scan -> wpa_supplicant_req_scan
1 int res = eloop_deplete_timeout(sec, usec, wpa_supplicant_scan, wpa_s, 2 NULL); 3 if (res == 1) { 4 wpa_dbg(wpa_s, MSG_DEBUG, "Rescheduling scan request: %d.%06d sec", 5 sec, usec); 6 }
wpa_supplicant_scan -> wpa_supplicant_trigger_scan
1 -> radio_add_work(wpa_s, 0, "scan", 0, wpas_trigger_scan_cb, ctx)
wpas_trigger_scan_cb -> wpa_drv_scan
1 static inline int wpa_drv_scan(struct wpa_supplicant *wpa_s, 2 struct wpa_driver_scan_params *params) 3 { 4 if (wpa_s->driver->scan2) // callback 5 return wpa_s->driver->scan2(wpa_s->drv_priv, params); 6 return -1; 7 }
grep scan2 callback
1 external/wpa_supplicant_8/wpa_supplicant$ grep -nr "scan2\s*=" . 2 ./src/drivers/driver_wext.c:2401: .scan2 = wpa_driver_wext_scan, 3 ./src/drivers/driver_privsep.c:726: .scan2 = wpa_driver_privsep_scan, 4 ./src/drivers/driver_test.c:2677: .scan2 = wpa_driver_test_scan, 5 ./src/drivers/driver_bsd.c:1618: .scan2 = wpa_driver_bsd_scan, 6 ./src/drivers/driver_nl80211.c:12612: .scan2 = driver_nl80211_scan2, 7 ./src/drivers/driver_ndis.c:3217: wpa_driver_ndis_ops.scan2 = wpa_driver_ndis_scan;
refer to ./src/drivers/driver_nl80211.c:12612
driver_nl80211_scan2 -> wpa_driver_nl80211_scan
1 msg = nl80211_scan_common(drv, NL80211_CMD_TRIGGER_SCAN, params, 2 bss->wdev_id_set ? &bss->wdev_id : NULL); 3 if (!msg) 4 return -1;
use NL80211_CMD_TRIGGER_SCAN talk with kernel(cfg80211.ko)
kernel
grep NL80211_CMD_TRIGGER_SCAN in kernel source:
1 kernel$ cgrep NL80211_CMD_TRIGGER_SCAN 2 ./net/wireless/nl80211.c:9053: .cmd = NL80211_CMD_TRIGGER_SCAN, 3 ./net/wireless/nl80211.c:9605: NL80211_CMD_TRIGGER_SCAN) < 0) { 4 ./include/uapi/linux/nl80211.h:255: * option to specify additional IEs in NL80211_CMD_TRIGGER_SCAN, 5 ./include/uapi/linux/nl80211.h:260: * @NL80211_CMD_TRIGGER_SCAN: trigger a new scan with the given parameters 6 ./include/uapi/linux/nl80211.h:759: NL80211_CMD_TRIGGER_SCAN, 7 ./include/uapi/linux/nl80211.h:1362: * This attribute is used with %NL80211_CMD_TRIGGER_SCAN and 8 ./include/uapi/linux/nl80211.h:3863: * of NL80211_CMD_TRIGGER_SCAN and NL80211_CMD_START_SCHED_SCAN
refer to net/wireless/nl80211.c:9053
1 static struct genl_ops nl80211_ops[] = { 2 3 // ... ... 4 5 { 6 .cmd = NL80211_CMD_TRIGGER_SCAN, 7 .doit = nl80211_trigger_scan, 8 .policy = nl80211_policy, 9 .flags = GENL_ADMIN_PERM, 10 .internal_flags = NL80211_FLAG_NEED_WDEV_UP | 11 NL80211_FLAG_NEED_RTNL, 12 }, 13 14 // ... ... 15 };
nl80211_trigger_scan -> rdev_scan(rdev, request);
1 static inline int rdev_scan(struct cfg80211_registered_device *rdev, 2 struct cfg80211_scan_request *request) 3 { 4 int ret; 5 trace_rdev_scan(&rdev->wiphy, request); 6 ret = rdev->ops->scan(&rdev->wiphy, request); // callback 7 trace_rdev_return_int(&rdev->wiphy, ret); 8 return ret; 9 }
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driver
參考高通文檔
- 1. 【轉載】Android WiFi 架構總覽（模塊及接口）
- 2. Android WiFi 架構總覽（模塊及接口）
- 3. ESP8266串口轉wifi/wifi轉串口模塊
- 4. Android app架構經驗總結（轉載）
- 5. Wifi模塊—Wifi系統框架
- 6. ATK-ESP8266 串口轉WIFI模塊 簡歷
- 7. 網卡類WiFi模塊系列一：USB接口單頻單通道WiFi模塊
- 8. Android hwcomposer模塊接口
- 9. Android架構思考(模塊化、多進程)(轉載學習)
- 10. ESP8266串口WiFi模塊
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