802.11無(wú)線網(wǎng)卡界面上的wifi信號(hào)強(qiáng)度是怎么獲取的？

九陽(yáng)神功愛(ài)喝茶

     小弟用的是ath9k的源碼，經(jīng)過(guò)分析我大概可以分析出來(lái)應(yīng)該是通過(guò)beacon幀的攜帶的信息獲取的。流程大概如下所示
ieee80211_rx_h_mgmt調(diào)用ieee80211_queue_work(&rx->local->hw, &sdata->work);也就是進(jìn)入了iface.c中的ieee80211_iface_work函數(shù)；這在個(gè)函數(shù)中接著調(diào)用
ieee80211_sta_rx_queued_mgmt（這里考慮AP模式下的情況）；進(jìn)而調(diào)用ieee80211_rx_mgmt_beacon這個(gè)函數(shù)，這個(gè)函數(shù)通過(guò)依次調(diào)用ieee80211_bss_info_update， cfg80211_inform_bss_width_frame 和cfg80211_bss_update函數(shù)將接收到的BSS信息保存在rdev中；最后一個(gè)函數(shù)cfg中可以看到是一個(gè)紅黑樹(shù)的基本操作，如果之前的BSS存在則更新，不存在則創(chuàng)建一個(gè)新的插入進(jìn)去，代碼非常值得一看。
     這里我遇到的問(wèn)題是rdev中的數(shù)據(jù)是如何被上層獲取的，一般來(lái)說(shuō)都是通過(guò)cfg.c中定義的函數(shù)獲取并返回用戶態(tài)。下面是cfg.c中定義的全部ops但是我并沒(méi)有找到是獲取BSS信息的。請(qǐng)各位大神多多指點(diǎn)，不甚感激。

1. const struct cfg80211_ops mac80211_config_ops = {
   
2.         .add_virtual_intf = ieee80211_add_iface,
   
3.         .del_virtual_intf = ieee80211_del_iface,
   
4.         .change_virtual_intf = ieee80211_change_iface,
   
5.         .start_p2p_device = ieee80211_start_p2p_device,
   
6.         .stop_p2p_device = ieee80211_stop_p2p_device,
   
7.         .add_key = ieee80211_add_key,
   
8.         .del_key = ieee80211_del_key,
   
9.         .get_key = ieee80211_get_key,
   
10.         .set_default_key = ieee80211_config_default_key,
    
11.         .set_default_mgmt_key = ieee80211_config_default_mgmt_key,
    
12.         .start_ap = ieee80211_start_ap,
    
13.         .change_beacon = ieee80211_change_beacon,
    
14.         .stop_ap = ieee80211_stop_ap,
    
15.         .add_station = ieee80211_add_station,
    
16.         .del_station = ieee80211_del_station,
    
17.         .change_station = ieee80211_change_station,
    
18.         .get_station = ieee80211_get_station,
    
19.         .dump_station = ieee80211_dump_station,
    
20.         .dump_survey = ieee80211_dump_survey,
    
21. #ifdef CPTCFG_MAC80211_MESH
    
22.         .add_mpath = ieee80211_add_mpath,
    
23.         .del_mpath = ieee80211_del_mpath,
    
24.         .change_mpath = ieee80211_change_mpath,
    
25.         .get_mpath = ieee80211_get_mpath,
    
26.         .dump_mpath = ieee80211_dump_mpath,
    
27.         .update_mesh_config = ieee80211_update_mesh_config,
    
28.         .get_mesh_config = ieee80211_get_mesh_config,
    
29.         .join_mesh = ieee80211_join_mesh,
    
30.         .leave_mesh = ieee80211_leave_mesh,
    
31. #endif
    
32.         .change_bss = ieee80211_change_bss,
    
33.         .set_txq_params = ieee80211_set_txq_params,
    
34.         .set_monitor_channel = ieee80211_set_monitor_channel,
    
35.         .suspend = ieee80211_suspend,
    
36.         .resume = ieee80211_resume,
    
37.         .scan = ieee80211_scan,
    
38.         .sched_scan_start = ieee80211_sched_scan_start,
    
39.         .sched_scan_stop = ieee80211_sched_scan_stop,
    
40.         .auth = ieee80211_auth,
    
41.         .assoc = ieee80211_assoc,
    
42.         .deauth = ieee80211_deauth,
    
43.         .disassoc = ieee80211_disassoc,
    
44.         .join_ibss = ieee80211_join_ibss,
    
45.         .leave_ibss = ieee80211_leave_ibss,
    
46.         .set_mcast_rate = ieee80211_set_mcast_rate,
    
47.         .set_wiphy_params = ieee80211_set_wiphy_params,
    
48.         .set_tx_power = ieee80211_set_tx_power,
    
49.         .get_tx_power = ieee80211_get_tx_power,
    
50.         .set_antenna_gain = ieee80211_set_antenna_gain,
    
51.         .set_wds_peer = ieee80211_set_wds_peer,
    
52.         .rfkill_poll = ieee80211_rfkill_poll,
    
53.         CFG80211_TESTMODE_CMD(ieee80211_testmode_cmd)
    
54.         CFG80211_TESTMODE_DUMP(ieee80211_testmode_dump)
    
55.         .set_power_mgmt = ieee80211_set_power_mgmt,
    
56.         .set_bitrate_mask = ieee80211_set_bitrate_mask,
    
57.         .remain_on_channel = ieee80211_remain_on_channel,
    
58.         .cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
    
59.         .mgmt_tx = ieee80211_mgmt_tx,
    
60.         .mgmt_tx_cancel_wait = ieee80211_mgmt_tx_cancel_wait,
    
61.         .set_cqm_rssi_config = ieee80211_set_cqm_rssi_config,
    
62.         .mgmt_frame_register = ieee80211_mgmt_frame_register,
    
63.         .set_antenna = ieee80211_set_antenna,
    
64.         .get_antenna = ieee80211_get_antenna,
    
65.         .set_rekey_data = ieee80211_set_rekey_data,
    
66.         .tdls_oper = ieee80211_tdls_oper,
    
67.         .tdls_mgmt = ieee80211_tdls_mgmt,
    
68.         .probe_client = ieee80211_probe_client,
    
69.         .set_noack_map = ieee80211_set_noack_map,
    
70. #ifdef CONFIG_PM
    
71.         .set_wakeup = ieee80211_set_wakeup,
    
72. #endif
    
73.         .get_channel = ieee80211_cfg_get_channel,
    
74.         .start_radar_detection = ieee80211_start_radar_detection,
    
75.         .channel_switch = ieee80211_channel_switch,
    
76.         .set_qos_map = ieee80211_set_qos_map,
    
77.         .set_ap_chanwidth = ieee80211_set_ap_chanwidth,
    
78. };
    

復(fù)制代碼

九陽(yáng)神功愛(ài)喝茶

反復(fù)看了看這個(gè)問(wèn)題怎么解決，最后分析應(yīng)該是通過(guò)ieee80211_scan獲取各個(gè)BSS的信息的。
下面的圖片是獲取sta和當(dāng)前連接的AP之間的信息的調(diào)用

nswcfd

這記筆記的習(xí)慣挺好的，贊一個(gè)！

九陽(yáng)神功愛(ài)喝茶

問(wèn)題已經(jīng)解決，見(jiàn)二樓