扫描结果获取
supplicant_event(EVENT_SCAN_RESULTS)
wpa_supplicant_event_scan_results
_wpa_supplicant_event_scan_results
（1）wpa_supplicant_get_scan_results
--> wpa_drv_get_scan_results2 (获取扫描结果)
--> get_scan_results2
（2）wpas_select_network_from_last_scan
-->wpa_supplicant_pick_network
-->wpa_supplicant_select_bss
-->wpa_scan_res_match
-->wpa_blacklist_get (对比黑名单中，查看bssid是否在黑名单中)
-->disallowed_bssid
-->disallowed_ssid
-->wpa_supplicant_connect (发起关联请求)
-->wpa_supplicant_associate
-->wpas_start_assoc_cb
-->wpa_supplicant_pick_new_network
-->wpa_supplicant_associate
-->wpa_supplicant_req_sched_scan (周期性扫描)
-->wpa_supplicant_start_sched_scan
-->sched_scan
-->wpa_supplicant_req_new_scan (一次新的扫描)
-->wpa_supplicant_req_scan
-->wpa_supplicant_scan
-->wpa_supplicant_trigger_scan
-->radio_add_work (加入到工作队列中)
-->wpas_trigger_scan_cb
-->wpa_drv_scan
-->scan2