Wi-Fi

2020-05-07T14:31:28Z

Yabobay: /* Install necessary drivers and software */ Clear up some minor confusion

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

== Install necessary drivers and software ==

First make sure your wireless drivers are loaded properly. (if you are using a '''Broadcom chipset''', see the [[#Broadcom_Wi-Fi_Chipset_Users|section at the bottom of this post]].)

Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}, which are probably available to be installed in the base setup.
{{Cmd|apk add wireless-tools wpa_supplicant}}

== Manual Configuration ==

List your available network interfaces. If you don't see any wireless interfaces (e.g. {{Path|wlan0}}), you probably need to load and/or install extra drivers/firmware.
{{Cmd|ip link}}

Bring the desired interface up.
{{Cmd|ip link set wlan0 up}}

{{Note|If this errors with <code>ioctl 0x8914 failed: No error information</code>, that's <code>busybox ip</code>'s way of saying your wireless radio is rfkill'd. See [https://wiki.archlinux.org/index.php/Wireless_network_configuration#Rfkill_caveat here] for information on how to unblock your wireless radio; the base installation should have <code>busybox rfkill</code> available.}}

Use the interface to scan for wireless access points. Make sure the ESSID you want to connect to appears here.
{{Cmd|iwlist wlan0 scanning}}

Associate the interface with desired ESSID.
{{Cmd|iwconfig wlan0 essid ExampleWifi}}

Sanity check: the interface should be configured with {{Path|ESSID:"ExampleWifi"}}.
{{Cmd|iwconfig wlan0}}

Create a wpa_supplicant configuration stanza for the wireless access point.
{{Cmd|wpa_passphrase 'ExampleWifi' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa_supplicant.conf}}
''(Access point not broadcasting its SSID requires additional line <code>scan_ssid=1</code> in the file <code>wpa_supplicant.conf</code>)''

Start wpa_supplicant in the foreground to make sure the connection succeeds.
{{Cmd|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 {{Path|-B}} option.
{{Cmd|wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf}}

Configure the interface with an IP address.
{{Cmd|udhcpc -i wlan0}}

Sanity check: the interface should have an {{Path|inet}} address.
{{Cmd|ip addr show wlan0}}

== Automatic Configuration on System Boot ==

Add a stanza for the desired interface (e.g. {{Path|wlan0}}) to {{Path|/etc/network/interfaces}}:

<pre>
auto wlan0
iface wlan0 inet dhcp
</pre>

Make sure {{Path|/etc/wpa_supplicant/wpa_supplicant.conf}} is the correct configuration for the wireless access point you want to connect to.

Bring the interface down.

{{Cmd|ifconfig wlan0 down}}

Manually start wpa_supplicant.

{{Cmd|/etc/init.d/wpa_supplicant start}}

If all is well (confirm with the sanity checks in [[#Manual_Configuration|Manual Configuration]]), configure wpa_supplicant to start automatically on boot.

{{Cmd|rc-update add wpa_supplicant boot}}

=== Launching udhcpc through wpa_cli actions ===

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

{{Cmd|rc-update add wpa_cli boot}}

== Broadcom Wi-Fi Chipset Users ==

The Broadcom chipset is quite popular among older computers. You will need to compile the firmware manually for this chipset as it is not included.

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

{{Cmd|dmesg {{!}} grep Broadcom}}

First install the SDK an Git:
{{Cmd|apk add alpine-sdk git}}

Then git clone aports from git.alpinelinux.org.

{{Cmd|git clone git://git.alpinelinux.org/aports}}

Change your directory to '''aports/non-free/b43-firmware''', then build it.

{{Tip|You can't be root and must be a user of the group abuild (use groupadd f.e. '''addgroup $(whoami) abuild''')}}
{{Tip|If this is your first time building a package you will need to generate a key for use in signing packages (use '''abuild-keygen -a -i''')}}

{{Cmd|abuild -r}}

Install the generated packge file (it will be in ~/packages/) - make sure to pass '''--allow-untrusted'''

{{Cmd|apk add --allow-untrusted ~/packages/...pkg}}

Now we need fwcutter, which is executed from the firmware package:

{{Cmd|apk add b43-fwcutter b43-firmware}}

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

{{Cmd|modprobe b43}}

To automate this on startup add it to /etc/modules:

{{Cmd|echo b43 >> /etc/modules}}

Now continue with the normal instructions.

[[Category:Networking]]

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Wi-Fi