WiFi

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Pre-requites

Note Note: To configure Wi-Fi you need to install wireless tools first (done by default for APF27 / PPS / APF51 / APF6 / OPOS6UL) and of course also need to have a running Wi-Fi interface like: the one on APW extension board, APF51Dev or PPS devt boards, the one on APF6, the one on OPOS6UL or a USB to Wi-Fi adapter, with corresponding Linux drivers loaded.


Common operations

List network interfaces supporting Wi-Fi

 # iwconfig
 lo        no wireless extensions.
 
 eth0      no wireless extensions.
 
 sit0      no wireless extensions.
 
 wmaster0  no wireless extensions.
 
 wlan0     IEEE 802.11bg  ESSID:""  
           Mode:Managed  Frequency:2.412 GHz  Access Point: Not-Associated   
           Tx-Power=0 dBm   
           Retry min limit:7   RTS thr:off   Fragment thr=2352 B   
           Encryption key:off
           Power Management:off
           Link Quality:0/100  Signal level:112/146  Noise level:0/0
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
Note Note: Here our Wi-Fi network interface is called wlan0. Depending on the number of your network interfaces or their model, this name could change. For example if using the Libertas drivers, the interface may be called eth1 (if eth0 is already used). In that case replace wlan0 with your interface name.


Activate the WLAN interface

 # ifconfig wlan0 up

Show all Access Points (AP) available for your APF (here with wlan0 interface)

# iwlist wlan0 scan

wlan0     Scan completed :
          Cell 01 - Address: XX:XX:XX:66:47:48
                    ESSID:"TOTO"
                    Mode:Master
                    Channel:1
                    Frequency:2.412 GHz (Channel 1)
                    Quality=88/100  Signal level:25/100
                    Encryption key:on
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
                              9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Extra:tsf=00000009d398fec8
                    Extra: Last beacon: 1390ms ago
...

Connect to an unencrypted AP

# iwconfig wlan0 essid AP_NAME
  • Check it:
# iwconfig wlan0

Get an IP address

# udhcpc -i wlan0

Encryption settings

When configuring Wi-Fi cryptography, only WEP can be setup easily from a terminal with single commands. For a Wi-Fi network with a WPA/WPA2 protection system, you should install and configure wpa_supplicant.

Warning Warning: The Wi-Fi Alliance defined WPA/WPA2 protection protocol in response to serious weaknesses researchers had found in the previous system, WEP (Wired Equivalent Privacy). Therefore, we strongly recommend you to use WPA/WPA2 to protect your network. Our wpa_supplicant wiki page provides the procedure to configure a WPA/WPA2 access to your network


WEP configuration

This example is given for a Wi-Fi Access Point named armadeus, the encoding key used here is not recommended, of course ;) :

 # iwconfig wlan0 essid armadeus
 # iwconfig wlan0 key 12345678901234567890
 # ifconfig wlan0 up             (if interface is not already up)
 ADDRCONF(NETDEV_UP): wlan0: link is not ready
 # ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

Now, the Wi-Fi adapter is ready and attached :

 # iwconfig
 lo        no wireless extensions.
 
 eth0      no wireless extensions.
 
 sit0      no wireless extensions.
 
 wmaster0  no wireless extensions.
 
 wlan0     IEEE 802.11bg  ESSID:"armadeus"  
           Mode:Managed  Frequency:2.437 GHz  Access Point: 00:1B:2F:E7:E4:08   
           Bit Rate=2 Mb/s   Tx-Power=7 dBm   
           Retry min limit:7   RTS thr:off   Fragment thr=2352 B   
           Encryption key:XXXXXXXXXXXXXXXXXXXXXXXXXX   Security mode:restricted
           Power Management:off
           Link Quality:0/100  Signal level:73/146  Noise level:0/0
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
 

Accessing outside world

We can manually configure the network to access Internet via the Wi-Fi interface instead of the Ethernet one:

 # ifconfig eth0 down
 # ifconfig wlan0 192.168.0.212
 # route add default gw 192.168.0.1 dev wlan0

And configure the nameserver in /etc/resolv.conf

 domain dev.null
 nameserver 192.168.0.207
 ~                   
 ~
 ~

If you have a DHCP server on your network, you can also use it and previous steps (route+resolv.conf) will be done automatically:

# udhcpc -i wlan0

We can now ping the best website in the world :

 # ping www.armadeus.org
 PING www.armadeus.org (213.186.33.5): 56 data bytes
 64 bytes from 213.186.33.5: seq=0 ttl=122 time=66.735 ms
 64 bytes from 213.186.33.5: seq=1 ttl=122 time=50.392 ms
 ^C
 --- www.armadeus.org ping statistics ---
 2 packets transmitted, 2 packets received, 0% packet loss
 round-trip min/avg/max = 50.392/58.563/66.735 ms

Surf on the net

To surf on the web, you can use (for example) links software :

 # links www.armadeus.org

It's an ASCII internet browser. For more informations about Links.

Links