Linux下使用wpa_supplicant連線WPA加密方式的WIFI
目前可以使用wireless-tools 或wpa_supplicant工具來配置無線網路。請記住重要的一點是，對無線網路的配置是全域性性的，而非針對具體的介面。
wpa_supplicant是一個較好的選擇，但缺點是它不支援所有的驅動。請瀏覽wpa_supplicant網站獲得它所支援的驅動列表。另外，wpa_supplicant目前只能連線到那些你已經配置好ESSID的無線網路。wireless-tools支援幾乎所有的無線網絡卡和驅動，但它不能連線到那些只支援WPA的AP。
經過編譯後的wpa_supplicant源程式可以看到兩個主要的可執行工具：wpa_supplicant和wpa_cli。wpa_supplicant是核心程式，它和wpa_cli的關係就是服務和客戶端的關係：後臺執行wpa_supplicant，使用wpa_cli來搜尋、設定、和連線網路。
如何用wpa_supplicant使能一個wifi連線？
Step by step：
1、執行wpa_supplicant程式；
執行：/system/bin/wpa_supplicant -d -Dwext -iwlan0 -c/data/misc/wifi/wpa_supplicant.conf
其中：
-d ：增加除錯資訊
-Dwext ：wext，驅動名稱
-iwlan0 ：wlan0，網路介面名稱
/system/bin/wpa_supplicant ：wpa_supplicant可執行程式path
/data/misc/wifi/wpa_supplicant.conf ：wpa_supplicant的配置檔案path
2、執行命令列工具wpa_cli ；
執行 ：wpa_cli -iwlan0 -p/data/system/wpa_supplicant
注，-p/data/system/wpa_supplicant中的wpa_supplicant並不是可執行程式，而是個控制套接字。
此時會進入互動模式。其中互動模式的命令如下表：
|
Full command |
Short command |
Description |
|
status |
stat |
displays the current connection status |
|
disconnect |
disc |
prevents wpa_supplicant from connecting to any access point |
|
quit |
q |
exits wpa_cli |
|
terminate |
term |
kills wpa_supplicant |
|
reconfigure |
recon |
reloads wpa_supplicant with the configuration file supplied (-c parameter) |
|
scan |
scan |
scans for available access points (only scans it, doesn't display anything) |
|
scan_result |
scan_r |
displays the results of the last scan |
|
list_networks |
list_n |
displays a list of configured networks and their status (active or not, enabled or disabled) |
|
select_network |
select_n |
select a network among those defined to initiate a connection (ie select_network 0) |
|
enable_network |
enable_n |
makes a configured network available for selection (ie enable_network 0) |
|
disable_network |
disable_n |
makes a configured network unavailable for selection (ie disable_network 0) |
|
remove_network |
remove_n |
removes a network and its configuration from the list (ie remove_network 0) |
|
add_network |
add_n |
adds a new network to the list. Its id will be created automatically |
|
set_network |
set_n |
shows a very short list of available options to configure a network when supplied with no parameters. See next section for a list of extremely useful parameters to be used with set_network and get_network. |
|
get_network |
get_n |
displays the required parameter for the specified network. See next section for a list of parameters |
|
save_config |
save_c |
saves the configuration |
設定網路的基本格式：set_network <network id> <key> <parameter> [<parameter>]
顯示網路資訊的基本格式：get_network <network id> <key>
相應的引數如下表：
|
Key |
Description |
Parameters |
|
ssid |
Access point name |
string |
|
id_str |
String identifying the network |
string |
|
priority |
Connection priority over other APs |
number (0 being the default low priority) |
|
bssid |
Mac address of the access point |
mac address |
|
scan_ssid |
Enable/disbale ssid scan |
0, 1, 2 |
|
key_mgmt |
Type of key management |
WPA-PSK, WPA_EAP, None |
|
pairwise |
Pairwise ciphers for WPA |
CCMP, TKIP |
|
group=TKIP |
Group ciphers for WPA |
CCMP, TKIP, WEP104, WEP40 |
|
psk |
Pre-Shared Key (clear or encrypted) |
string |
|
wep_key0 |
WEP key (up to 4: wep_key[0123]) |
string |
|
eap |
Extensible Authentication Protocol |
MD5, MSCHAPV2, OTP, GTC, TLS, PEAP, TTLS |
|
identity |
EAP identity string |
string |
|
password |
EAP password |
string |
|
ca_cert |
Pathname to CA certificate file |
/full/path/to/certificate |
|
client_cert |
Pathname to client certificate |
/full/path/to/certificate (PEM/DER) |
|
private_key |
Pathname to a client private key file |
/full/path/to/private_key (PEM/DER/PFX) |
eg.1、連線無加密的AP
>add_network (It will display a network id for you, assume it returns 0)
>set_network 0 ssid "666"
>set_network 0 key_mgmt NONE
>enable_network 0
>quit
eg.2、連線WEP加密AP
>add_network (assume return 1)
>set_network 1 ssid "666"
>set_network 1 key_mgmt NONE
>set_network 1 wep_key0 "your ap password"
>enable_network 1
eg.3、連線WPA-PSK/WPA2-PSK加密的AP
>add_network (assume return 2)
>set_network 2 ssid "666"
>set_network 2 psk "your pre-shared key"
>enable_network 2
到此，wifi模組就能連線上AP了。
3、以上是通過命令列工具wpa_cli來實現wifi網路的連線。當然，也可以通過wpa_supplicant的配置檔案來實現連線。
再回顧下執行wpa_supplicant時執行的命令：
/system/bin/wpa_supplicant -d -Dwext -iwlan0 -c/data/misc/wifi/wpa_supplicant.conf
我們在執行時加上了-c/data/misc/wifi/wpa_supplicant.conf，我們可以將我們要連線的AP的設定以一定的格式寫入wpa_supplicant.conf配置檔案中即可。
eg.
ctrl_interface=DIR=/data/system/wpa_supplicant GROUP=system update_config=1
network={
ssid="my access point"
proto=WPA
key_mgmt=WPA-PSK
psk="you pass words"
}