Introduction to WPA Supplicant
WPA Supplicant is a Wi-Fi Protected Access
(WPA) client and IEEE 802.1X supplicant. It implements WPA key negotiation
with a WPA Authenticator and Extensible Authentication Protocol (EAP)
authentication with an Authentication Server. In addition, it controls the
roaming and IEEE 802.11 authentication/association of the wireless LAN
driver. This is useful for connecting to a password protected wireless
access point.
This package is known to build and work properly
using an LFS 11.3 platform.
Package Information
WPA Supplicant Dependencies
Recommended
desktop-file-utils-0.26 (for running
update-desktop-database) and
libnl-3.7.0
Optional
dbus-1.14.6,
libxml2-2.10.3, and
Qt-5.15.8
User Notes:
https://wiki.linuxfromscratch.org/blfs/wiki/wpa_supplicant
Kernel Configuration
Enable the following options in the kernel configuration as well as
specific device drivers for your hardware and recompile the kernel if
necessary:
[*] Networking support ---> [CONFIG_NET]
[*] Wireless ---> [CONFIG_WIRELESS]
<*/M> cfg80211 - wireless configuration API [CONFIG_CFG80211]
[*] cfg80211 wireless extensions compatibility [CONFIG_CFG80211_WEXT]
<*/M> Generic IEEE 802.11 Networking Stack (mac80211) [CONFIG_MAC80211]
Device Drivers --->
[*] Network device support ---> [CONFIG_NETDEVICES]
[*] Wireless LAN ---> [CONFIG_WLAN]
Open the submenu and select the options that support your hardware:
lspci from pciutils-3.9.0 can be used to
view your hardware configuration.
Installation of WPA Supplicant
First you will need to create an initial configuration file for the
build process. You can read wpa_supplicant/README
and wpa_supplicant/defconfig
for the explanation
of the following options as well as other options that can be used.
Create a build configuration file that should work for standard WiFi
setups by running the following command:
cat > wpa_supplicant/.config << "EOF"
CONFIG_BACKEND=file
CONFIG_CTRL_IFACE=y
CONFIG_DEBUG_FILE=y
CONFIG_DEBUG_SYSLOG=y
CONFIG_DEBUG_SYSLOG_FACILITY=LOG_DAEMON
CONFIG_DRIVER_NL80211=y
CONFIG_DRIVER_WEXT=y
CONFIG_DRIVER_WIRED=y
CONFIG_EAP_GTC=y
CONFIG_EAP_LEAP=y
CONFIG_EAP_MD5=y
CONFIG_EAP_MSCHAPV2=y
CONFIG_EAP_OTP=y
CONFIG_EAP_PEAP=y
CONFIG_EAP_TLS=y
CONFIG_EAP_TTLS=y
CONFIG_IEEE8021X_EAPOL=y
CONFIG_IPV6=y
CONFIG_LIBNL32=y
CONFIG_PEERKEY=y
CONFIG_PKCS12=y
CONFIG_READLINE=y
CONFIG_SMARTCARD=y
CONFIG_WPS=y
CFLAGS += -I/usr/include/libnl3
EOF
If you wish to use WPA Supplicant with
NetworkManager-1.42.0, make sure that you have installed
dbus-1.14.6 and libxml2-2.10.3, then add the
following options to the WPA Supplicant
build configuration file by running the following command:
cat >> wpa_supplicant/.config << "EOF"
CONFIG_CTRL_IFACE_DBUS=y
CONFIG_CTRL_IFACE_DBUS_NEW=y
CONFIG_CTRL_IFACE_DBUS_INTRO=y
EOF
cd wpa_supplicant &&
make BINDIR=/usr/sbin LIBDIR=/usr/lib
If you have installed Qt-5.15.8 and wish to build
the WPA Supplicant GUI program, run
the following commands:
Note
The following directory name is labelled qt4, but
is compatible with Qt-5.15.8.
pushd wpa_gui-qt4 &&
qmake wpa_gui.pro &&
make &&
popd
This package does not come with a test suite.
Now, as the root
user:
install -v -m755 wpa_{cli,passphrase,supplicant} /usr/sbin/ &&
install -v -m644 doc/docbook/wpa_supplicant.conf.5 /usr/share/man/man5/ &&
install -v -m644 doc/docbook/wpa_{cli,passphrase,supplicant}.8 /usr/share/man/man8/
If you have built WPA Supplicant with
D-Bus support, you will need to install
D-Bus configuration files. Install them
by running the following commands as the
root
user:
install -v -m644 dbus/fi.w1.wpa_supplicant1.service \
/usr/share/dbus-1/system-services/ &&
install -v -d -m755 /etc/dbus-1/system.d &&
install -v -m644 dbus/dbus-wpa_supplicant.conf \
/etc/dbus-1/system.d/wpa_supplicant.conf
If you have built the WPA Supplicant GUI
program, install it by running the following commands as the
root
user:
install -v -m755 wpa_gui-qt4/wpa_gui /usr/bin/ &&
install -v -m644 doc/docbook/wpa_gui.8 /usr/share/man/man8/ &&
install -v -m644 wpa_gui-qt4/wpa_gui.desktop /usr/share/applications/ &&
install -v -m644 wpa_gui-qt4/icons/wpa_gui.svg /usr/share/pixmaps/
Note
You will need to restart the system D-Bus daemon
before you can use the WPA Supplicant
D-Bus interface.
Note
This package installs desktop files into the
/usr/share/applications
hierarchy and you can improve system performance and memory usage by
updating /usr/share/applications/mimeinfo.cache
.
To perform the update you must have
desktop-file-utils-0.26 installed and issue the following
command as the root
user:
update-desktop-database -q
Configuring wpa_supplicant
Config File
/etc/sysconfig/wpa_supplicant-*.conf
Configuration Information
To connect to an access point that uses a password, you need to put
the pre-shared key in
/etc/sysconfig/wpa_supplicant-wifi0
.conf
.
SSID is the string that the access point/router transmits to
identify itself. Run the following command as the
root
user:
wpa_passphrase SSID
SECRET_PASSWORD
> /etc/sysconfig/wpa_supplicant-wifi0
.conf
/etc/sysconfig/wpa_supplicant-wifi0
.conf
can hold the details of several access points. When
wpa_supplicant is started, it will scan for the
SSIDs it can see and choose the appropriate password to connect.
If you want to connect to an access point that isn't password
protected, put an entry like this in
/etc/sysconfig/wpa_supplicant-wifi0
.conf
.
Replace "Some-SSID" with the SSID of the access point/router.
network={
ssid="Some-SSID
"
key_mgmt=NONE
}
Connecting to a new access point that is not in the configuration
file can be accomplished manually via the command line or GUI, but it
must be done via a privileged user. To do that, add the following to
the configuration file:
ctrl_interface=DIR=/run/wpa_supplicant GROUP=<privileged group>
update_config=1
Replace the <privileged group> above with a system group where
members have the ability to connect to a wireless access point.
There are many options that you could use to tweak how you connect
to each access point. They are described in some detail in the
wpa_supplicant/wpa_supplicant.conf
file in the
source tree.
Connecting to an Access Point
If you want to configure network interfaces at boot using
wpa_supplicant, you need to install the
/lib/services/wpa
script
included in blfs-bootscripts-20230101 package:
make install-service-wpa
If your router/access point uses DHCP to allocate IP addresses, you
can install DHCP-4.4.3-P1 client and use it to
automatically obtain network addresses. Create the
/etc/sysconfig/ifconfig-wifi0
by running the following command as the
root
user:
cat > /etc/sysconfig/ifconfig.wifi0
<< "EOF"
ONBOOT="yes"
IFACE="wlan0
"
SERVICE="wpa"
# Additional arguments to wpa_supplicant
WPA_ARGS=""
WPA_SERVICE="dhclient"
DHCP_START=""
DHCP_STOP=""
# Set PRINTIP="yes" to have the script print
# the DHCP assigned IP address
PRINTIP="no"
# Set PRINTALL="yes" to print the DHCP assigned values for
# IP, SM, DG, and 1st NS. This requires PRINTIP="yes".
PRINTALL="no"
EOF
If you prefer dhcpcd-9.4.1 instead of
DHCP-4.4.3-P1 client, then create the
/etc/sysconfig/ifconfig-wifi0
by running the following command as the
root
user:
cat > /etc/sysconfig/ifconfig.wifi0
<< "EOF"
ONBOOT="yes"
IFACE="wlan0
"
SERVICE="wpa"
# Additional arguments to wpa_supplicant
WPA_ARGS=""
WPA_SERVICE="dhcpcd"
DHCP_START="-b -q <insert appropriate start options here>
"
DHCP_STOP="-k <insert additional stop options here>
"
EOF
Alternatively, if you use static addresses on your local network,
then create the
/etc/sysconfig/ifconfig-wifi0
by running the following command as the
root
user:
cat > /etc/sysconfig/ifconfig.wifi0
<< "EOF"
ONBOOT="yes"
IFACE="wlan0
"
SERVICE="wpa"
# Additional arguments to wpa_supplicant
WPA_ARGS=""
WPA_SERVICE="ipv4-static"
IP="192.168.1.1"
GATEWAY="192.168.1.2"
PREFIX="24"
BROADCAST="192.168.1.255"
EOF
You can connect to the wireless access point by
running the following command as the
root
user:
ifup wifi0
Replace wlan0
with the correct
wireless interface and wifi0
with desired name for the configuration file. Please note
that wpa_supplicant-*.conf
and
ifconfig.*
configuration files need
to have identical names, ie both contain
wifi0
in their name.