Wi-Fi: Difference between revisions

Revision as of 20:15, 26 May 2023

This page describes how to set up a wireless network connection with WPA encryption.

Choose a wireless daemon between iwd and wpa_supplicant

Prerequisites

Working wireless drivers

Note: in most cases installing linux-firmware should get you the required drivers. Installation of this package can produce errors on diskless or data disk modes. If such errors occur, switch to system disk mode.

If you are using a Broadcom chipset, see the Broadcom Wi-Fi section.)

iwd

iwd (iNet wireless daemon) is a wireless daemon written by Intel and aiming at replacing wpa_supplicant. The core goal of the project is to optimize resource utilization by not depending on any external libraries and instead utilizing features provided by the Linux Kernel to the maximum extent possible.

iwd is supported since Alpine Linux 3.10.

To get started, install iwd:

apk add iwd

To do anything with iwd, it has to be running:

rc-service iwd start

If it was not running, running iwctl .. commands will print

The name net.connman.iwd was not provided by any .service files  
Failed to retrieve IWD dbus objects, quitting...

and running just iwctl will say it is waiting for IWD to start.

List your available wifi device(s) (you probably have wlan0):

iwctl device list

If you don't know the SSID of your network you can run a scan and retrieve a list of all the detected networks:

iwctl station wlan0 scan && iwctl station wlp8s0 get-networks

To connect to a network:

iwctl station wlan0 connect <SSID>

Note: iwd automatically stores network passphrases in the /var/lib/iwd directory and uses them to auto-connect in the future. If you run diskless Alpine, make sure to include this directory to the apkovl and commit:

lbu add /var/lib/iwd && lbu commit -d

Note: Since version 1.10, iwd supports IPv6, but it is disabled by default. To enable it, add the following to the configuration file:

Contents of /etc/iwd/main.conf

[Network]
EnableIPv6=true

Finally, configure iwd and its dependency dbus to start automatically on boot:

rc-update add iwd boot && rc-update add dbus boot

Add a entry for the desired interface (e.g. wlan0):

Contents of /etc/network/interfaces

auto wlan0
iface wlan0 inet dhcp

Note: You could instead use the iwd's built-in network configuration by setting EnableNetworkConfiguration=true in /etc/iwd/main.conf

Manually restart networking:

rc-service networking restart

Your wifi interface should now be up and have a dedicated IP adress:

ip a show wlan0

Useful link: Archlinux wiki page if you need more specific configuration.

wpa_supplicant

To get started install wpa_supplicant

apk add wpa_supplicant

To list your available network interfaces:

Note: if you don't see any wireless interfaces (e.g. wlan0), you probably need to load and/or install drivers/firmware.

ip link

or

ip a

Bring up the desired interface:

ip link set wlan0 up

Note: If this errors with ioctl 0x8914 failed: No error information, that's busybox ip's way of saying your wireless radio is rfkill'd. See the Rfkill section for information on how to unblock your wireless radio.

Use this command to add your Wi-Fi network to wpa_supplicant:

wpa_passphrase 'ExampleWifiSSID' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa_supplicant.conf

(Access point not broadcasting its SSID requires additional line scan_ssid=1 in the file wpa_supplicant.conf)

Note: the Wi-Fi SSID and password are case sensitive and the single quote before and after the SSID and password need to be there

Start wpa_supplicant in the foreground to make sure the connection succeeds.

wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

If all is well, run it as a daemon in the background by setting the -B option.

wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf

Configure the interface with an IP address.

udhcpc -i wlan0

Sanity check: the interface should have a inet address.

ip addr show wlan0

Automatic Configuration on System Boot

Add a entry for the desired interface (e.g. wlan0):

Contents of /etc/network/interfaces

auto wlan0
iface wlan0 inet dhcp

Note: Dont remove or comment out the auto lo entry

Sanity check: Make sure /etc/wpa_supplicant/wpa_supplicant.conf is the correct configuration for the wireless access point you want to connect to.

Bring the interface down.

ip link set wlan0 down

Manually restart (or start) networking.

/etc/init.d/networking --quiet restart &

If all is well (feel free to confirm with the sanity checks),

Configure wpa_supplicant to start automatically on boot:

# rc-update add wpa_supplicant boot

Also make sure networking is set to automatically start on boot:

# rc-update add networking boot

Optional security precaution:

By default wpa_supplicant will store your Wi-Fi password in plain text:

Contents of (Example) /etc/wpa_supplicant/wpa_supplicant.conf

network={
    ssid="<YourSSIDShouldBeHere>"
        #psk="<YourPasswordShouldBeHereInPlainText>"
    psk=<RandomLettersAndNumbersShouldBeHere>
}

this is not necessary and wpa_supplicant should funtion just fine without it, if you dont want your stored password in plain text just delete the line with #psk="<YourPasswordShouldBeHereInPlainText>" on it.

Launching udhcpc through wpa_cli actions

Todo: Figure out if theses two sections are different or connected to one another

With the above configuration, udhcpc will only run once at boot. If the Wifi isn't available then, or the network changes in between, it needs to be notified. This is done through the wpa_cli action script in /etc/wpa_supplicant/wpa_cli.sh

Automatic Reconnection when WIFI signal is lost

To enable automatic reconnection when wifi signal is lost add these to config:

Contents of /etc/wpa_supplicant/wpa_supplicant.conf

ap_scan=1
autoscan=periodic:10
disable_scan_offload=1

rc-update add wpa_cli boot

Troubleshooting

Broadcom Wi-Fi Chipset Users

The Broadcom chipset is quite popular among older computers. The b43 driver is included in the linux-lts or linux-edge kernel packages. However, you might need to compile the firmware manually for this chipset as it is not included in linux-firmware for some cargs.

You can check if you have a Broadcom chipset by using lspci:

lspci -nn -d 14e4:

Now we need fwcutter:

apk add b43-fwcutter

Now we have everything to download the proprietary driver and extract the firmware from it:

export FIRMWARE_INSTALL_DIR="/lib/firmware"
wget http://www.lwfinger.com/b43-firmware/broadcom-wl-5.100.138.tar.bz2
tar xjf broadcom-wl-5.100.138.tar.bz2
sudo b43-fwcutter -w "$FIRMWARE_INSTALL_DIR" broadcom-wl-5.100.138/linux/wl_apsta.o

More information can be found here.

Now you need to use modprobe so the device will show up:

modprobe b43

Now continue with the normal instructions.

Rfkill

Many laptops have a hardware button (or switch) to turn off wireless card, however, the card can also be blocked by kernel. This can be changed using rfkill. To show the current of your Wi-Fi:

Contents of (example) $ rfkill list

0: phy0: wlan
    Soft blocked: no
    Hard blocked: no

If the card is hard-blocked, use the hardware button or switch to unblock it. If the card is not hard-blocked but soft-blocked, use the following command:

# rfkill unblock wifi