wifi client access for your raspberry

A simple but efficient tutorial on what you need to connect your Raspberry board to an Wifi acces-point

Having plug your wifi dongle and load hid driver, you probably want to use your raspberry as a router.

This article will explain you how to procede.

At first, you need to install wpa-supplicant tools

$atitude install wpa-supplicant

This program support  IEEE 802.11i protocol and authentification protocols (WPA2, WPA, WEP,…)

If your distribution do not support this binary, you can download it here, and compil with this Makefile :

I use wpa-supplicant source code provided by TRENDnet (manufacturer of my wifi dongle chip):

ROOTFS= #your Rpi filesystem
WIRELESS_DIR=./wireless #the directory where your install the archive
CROSS_COMPILE=arm-linux-gnueabi- #the cross-compiler prefix
CC=$(CROSS_COMPILE)gcc #the arm gcc to use

all: extract compil install

extract:
 @(echo "extacting wpa_supplicant archive")
 @(unzip $(WIRELESS_DIR)/RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/wpa_supplicant_hostapd/wpa_supplicant_hostapd-0.8_rtw_20120803.zip \
 -d $(WIRELESS_DIR)/RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/wpa_supplicant_hostapd/)

compil:
 @(echo "compiliong wpa_supplicant source code")
 @(sed -i '1iCC=$(CC)' \
 $(WIRELESS_DIR)/RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/wpa_supplicant_hostapd/wpa_supplicant_hostapd-0.8/wpa_supplicant/Makefile)
 @(make -C $(WIRELESS_DIR)/RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/wpa_supplicant_hostapd/wpa_supplicant_hostapd-0.8/wpa_supplicant )
 @(test -d $(ROOTFS)/etc/wpa_supplicant || mkdir $(ROOTFS)/etc/wpa_supplicant)

install:
 @(echo "installing wpa_supplicant in $(ROOTFS) directory")
 @(echo "CP wpa_supplicant")
 @(cp $(BIN_DIR)/wpa_supplicant/wpa_supplicant $(ROOTFS)/sbin/)
 @(echo "CP wpa_cli")
 @(cp $(BIN_DIR)/wpa_supplicant/wpa_cli $(ROOTFS)/sbin/)
 @(echo "CP wpa_passphrase")
 @(cp $(BIN_DIR)/wpa_supplicant/wpa_passphrase $(ROOTFS)/sbin/)

.PHONY: extract compil install

A simple “$make all” will install wpa_supplicant, wpa_cli, and wpa_passphrase in your filesystem.

Create a /etc/wpa-supplicant.conf in order to put information needed to connect to a wifi acces-point.

$touch  /etc/wpa-supplicant.conf

add this in this file :

ctrl_interface=/var/run/wpa_supplicant
ap_scan=1
update_config=1
# WPA-Personal(PSK) with TKIP and enforcement for frequent PTK rekeying
network={
 ssid="your_ssid_name"
 scan_ssid=1
 proto=WPA
 key_mgmt=WPA-PSK
 #psk="your_uncrypted_key"
 psk=your_crypted_key
}

your_crypted_key is obtained with the following command

$wpa_passphrase your_ssid_name your_uncrypted_key

Now, you need to modify your general network configuration (/etc/network/interfaces file) and add this

auto wlan0
iface wlan0 inet dhcp
 pre-up wpa_supplicant -B -iwlan0 -c/etc/wpa_supplicant/wpa_supplicant.conf
 post-down killall -q wpa_supplicant

Now you have to reboot your board, or reload networking deamon :

$/etc/init.d/networking restart

Enjoy:

$iwlist wlan0