Wi-Fi: Difference between revisions

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m (less verbose wpa_passphrase invocation. Also, should be using /etc/wpa_supplicant prefix.)
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This document describes how to set up a wireless network connection with WPA encryption.
This page describes how to set up a wireless network connection with WPA encryption using [[#wpa_supplicant|wpa_supplicant]].  


== Install necessary drivers and software  ==
== Prerequisites ==


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]].)
Working wireless drivers. In most cases installing {{Pkg|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.
To list your available network interfaces:


Install {{Pkg|wireless-tools}} and {{Pkg|wpa_supplicant}}.
{{Cmd|ip link}}
{{Cmd|apk add wireless-tools wpa_supplicant}}
 
or
 
{{Cmd|ip a}}
 
Refer to [[#Troubleshooting|Troubleshooting]] section to see if you don't see any wireless interfaces (e.g. {{Path|wlan0}}). You probably need to load and/or install drivers/firmware. If you are using a '''Broadcom chipset''', see the [[#Broadcom_Wi-Fi_Chipset_Users|Broadcom Wi-Fi section]].


== Manual Configuration  ==
Bring up the desired interface:
{{Cmd|# ip link set wlan0 up}}


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.
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 the [[#Rfkill|Rfkill section]] for information on how to unblock your wireless radio.
{{Cmd|ip link}}


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


Use the interface to scan for wireless access points. Make sure the ESSID you want to connect to appears here.
{{Tip| [[NetworkManager]],  the standard Linux network configuration tool suite supports both wireless daemons i.e [[iwd]] and [[#wpa_supplicant|wpa_supplicant]]. Using both may lead to conflicts.}}
{{Cmd|iwlist wlan0 scanning}}


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


Sanity check: the interface should be configured with {{Path|ESSID:"ExampleWifi"}}.
[[Configure_Networking#Network_setup-scripts|Network setup-scripts]] can configure your wifi quickly using <code>wpa_supplicant</code>. If it does not meet your requirement, please follow the steps outlined on this page.  
{{Cmd|iwconfig wlan0}}


Create a wpa_supplicant configuration stanza for the wireless access point.
To get started install {{Pkg|wpa_supplicant}}
{{Cmd|wpa_passphrase 'ExampleWifi' 'ExampleWifiPassword' > /etc/wpa_supplicant/wpa.conf}}


From one terminal/console, start wpa_supplicant with the generated config:
{{Cmd|# apk add wpa_supplicant}}
{{Cmd|wpa_supplicant -Dwext -iwlan0 -c ./wpa.conf}}


From another terminal/console, start dhcpcd:
Use this command to add your Wi-Fi network to wpa_supplicant:
{{Cmd|udhcpc -i wlan0}}
{{Cmd|# wpa_passphrase 'ExampleWifiSSID' '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>)''


The wlan0 interface should be configured with an IP address at this point:
{{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}}
{{Cmd|ifconfig wlan0}}


== Automatic Configuration on System Boot  ==
Start wpa_supplicant in the foreground to make sure the connection succeeds.
{{Cmd|# wpa_supplicant -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf}}


Add an interface stanza for wlan0 to the file {{Path|/etc/network/interfaces}}
<br>
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}}


<pre>
<br>
auto wlan0
Configure the interface with an IP address.
iface wlan0 inet dhcp
{{Cmd|# udhcpc -i wlan0}}
</pre>


Create {{Path|/etc/wpa_supplicant}} if it doesn't already exist, set sane permissions and append the configuration {{Path|wpa.conf}} to {{Path|wpa_supplicant.conf}}.
Sanity check: the interface should have a {{Path|inet}} address.
{{Cmd|$ ip addr show wlan0}}


<pre>
<br>
mkdir -p /etc/wpa_supplicant
chmod 750 /etc/wpa_supplicant
cat wpa.conf >> /etc/wpa_supplicant/wpa_supplicant.conf
</pre>


Test the automatic interface configuration:
=== Automatic Configuration on System Boot  ===


Bring the interface down:
Add a entry for the desired interface (e.g. {{Path|wlan0}}):
{{Cat|/etc/network/interfaces|auto lo
auto wlan0
iface wlan0 inet dhcp}}


{{Cmd|ifconfig wlan0 down}}
{{Warning|Don't remove or comment out the '''auto lo''' entry}}


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


{{Cmd|/etc/init.d/wpa_supplicant start}}
Bring the interface down.


The wlan0 interface should be associated with the MyNet SSID:
{{Cmd|# ip link set wlan0 down}}


{{Cmd|iwconfig wlan0}}
<br>
Manually restart (or '''start''') '''networking'''.


The wlan0 interface should have been assigned an IP address via DHCP:
{{Cmd|# rc-service networking --quiet restart &}}


{{Cmd|ifconfig wlan0}}
<br>
Perform sanity checks like ping and browsing. For issues related to name resolution, refer [[Configure_Networking#Configuring_DNS|Networking]] page.


Configure wpa_supplicant to start automatically on boot:
If all is well, Configure wpa_supplicant to start automatically on boot:


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


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


{{Cmd|reboot}}
{{Cmd|# rc-update add networking boot}}


Log in and check that the interface is associated with the access point:
'''Optional security precaution:'''


{{Cmd|iwconfig wlan0}}
By default {{Pkg|wpa_supplicant}} will store your Wi-Fi password in plain text:


Check that the interface was assigned an IP address via DHCP:
{{Cat|(Example) /etc/wpa_supplicant/wpa_supplicant.conf|<nowiki>network={
    ssid="<YourSSIDShouldBeHere>"
        #psk="<YourPasswordShouldBeHereInPlainText>"
    psk=<RandomLettersAndNumbersShouldBeHere>
}</nowiki>}}


{{Cmd|ifconfig wlan0 {{!}} grep addr}}
this is not necessary and {{Pkg|wpa_supplicant}} should funtion just fine without it, if you dont want your stored password in plain text just delete the line with <code>#psk="<YourPasswordShouldBeHereInPlainText>"</code> on it.


=== Launching udhcpc through wpa_cli actions ===
=== Launching udhcpc through wpa_cli actions ===


With the above configuration, udhcpc will only run once at boot.
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.
If the Wifi isn't available then, or the network changes after booting, udhcpc needs to be notified.
This is done through the wpa_cli action script in /etc/wpa_supplicant/wpa_cli.sh
You can automatically notify udhcpc of network changes by using a wpa_cli action file, such as the one installed by default at `/etc/wpa_supplicant/wpa_cli.sh`.
 
To manually start a wpa_cli daemon with an action file, use the `-a` option:
 
{{Cmd|# wpa_cli -a /etc/wpa_supplicant/wpa_cli.sh}}
 
<br>
To do this automatically, use the `wpa_cli` service included in {{Pkg|wpa_supplicant-openrc}}:
 
{{Cat|/etc/conf.d/wpa_cli|<nowiki>WPACLI_OPTS="-a /etc/wpa_supplicant/wpa_cli.sh"</nowiki>}}
 
{{Cmd|# rc-update add wpa_cli boot}}
 
== Troubleshooting ==
 
=== Check dmesg ===


{{Cmd|rc-update add wpa_cli boot}}
Run dmesg and check for errors related to the wireless interface. Usually, dmesg gives maximum information related to network and all other hardware.
{{Cmd|# dmesg |grep wlan}}
or
{{Cmd|# dmesg}}


== Broadcom Wi-Fi Chipset Users  ==
=== checking network cards ===


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.
{{Cmd|$ cat /proc/net/dev }} lists the network interfaces that are detected. If the expected interfaces are not available, Check what network hardware chip you have using lspci or lsusb:


You can check if you have a Broadcom chipset by using dmesg:
{{Cmd|$ lspci -nn }}
{{Cmd|$ lsusb }}


{{Cmd|dmesg {{!}} grep Broadcom}}
Refer [[How to get regular stuff working#Hardware_Management|hardware management]], if the default outputs shown above lacks sufficient information.


First install the SDK an Git:
Check what driver the card uses and modprobe it. Check that the card is in master mode.
{{Cmd|apk add alpine-sdk git}}
Check what driver you need on the [https://wireless.wiki.kernel.org/en/users/Drivers/b43#list_of_hardware b43 compatibility page]


Then git clone aports from git.alpinelinux.org.
=== 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 cards.


{{Cmd|git clone git://git.alpinelinux.org/aports}}
To check what broadcom chip you have using lspci:


Change your directory to '''aports/non-free/b43-firmware''', then build it.
{{Cmd|$ lspci -nn -d 14e4:}}


{{Tip|You can't be root and must be a user of the group abuild (use groupadd f.e. '''groupadd $(whoami) abuild''')}}
====B43====
{{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}}
Download firmware cutter.


Install the generated packge file (it will be in ~/packages/) - make sure to pass '''--allow-untrusted'''
{{Cmd|$ apk add b43-fwcutter}}


{{Cmd|apk add --allow-untrusted ~/packages/...pkg}}
Now we have everything to download the proprietary driver and extract the firmware from it:


Now we need fwcutter, which is executed from the firmware package:
{{Cmd|<nowiki># 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
$ b43-fwcutter -w "$FIRMWARE_INSTALL_DIR" broadcom-wl-5.100.138/linux/wl_apsta.o</nowiki>}}


{{Cmd|apk add b43-fwcutter b43-firmware}}
More information can be found [http://linuxwireless.sipsolutions.net/en/users/Drivers/b43/#Other_distributions_not_mentioned_above here].


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


{{Cmd|modprobe b43}}
{{Cmd|# modprobe b43}}
 
Now continue with the normal instructions.


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


{{Cmd|echo b43 >> /etc/modules}}
First install the software we need to build a driver[https://unix.stackexchange.com/questions/606073/how-to-build-kernel-modules-in-alpine-3-12 ^]:
 
{{Cmd|apk add git alpine-sdk linux-headers}}
 
Then install the driver build repo (this is archived, however it's legacy so that doesn't matter):
 
{{Cmd|git clone https://github.com/antoineco/broadcom-wl
cd broadcom-wl
}}
 
Then follow the build instructions listed in the git repo:
 
{{Cmd|make
doas make install
doas depmod -A
doas modprobe wl
}}
 
reboot and you have a working wl driver!


Now continue with the normal instructions.  
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:
<p style="background-color:#f9f9f9; border:1px dashed #2f6fab; line-height:1.1em; padding:1em; font-family:monospace; font-size:10pt; white-space:pre; overflow:auto;"><span style="color:green;">~</span>'''$''' rfkill list
0: phy0: wlan
    Soft blocked: no
    Hard blocked: no
</p>
<br>
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:
{{Cmd|# rfkill unblock wifi}}
<br>
== See Also ==
* [[Configure_Networking| Networking in Alpine Linux]]
* [[Iwd|iwd]] - An alternate to wpa_supplicant
* [[NetworkManager]] - Front-end to Networking
* [https://wiki.postmarketos.org/wiki/WiFi PostmarketOS Wiki]
* [https://wiki.archlinux.org/title/Network_configuration/Wireless Archwiki]
* [https://wiki.gentoo.org/wiki/Wi-Fi Gentoo Wiki]


[[Category:Networking]]
[[Category:Networking]]

Latest revision as of 10:42, 18 October 2024

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

Prerequisites

Working wireless drivers. 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. To list your available network interfaces:

ip link

or

ip a

Refer to Troubleshooting section to see if you don't see any wireless interfaces (e.g. wlan0). You probably need to load and/or install drivers/firmware. If you are using a Broadcom chipset, see the Broadcom Wi-Fi section.

Bring up the desired interface:

# ip link set wlan0 up

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.

iwd

Main article: iwd
Tip: NetworkManager, the standard Linux network configuration tool suite supports both wireless daemons i.e iwd and wpa_supplicant. Using both may lead to conflicts.

wpa_supplicant

Network setup-scripts can configure your wifi quickly using wpa_supplicant. If it does not meet your requirement, please follow the steps outlined on this page.

To get started install wpa_supplicant

# apk add wpa_supplicant

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 lo auto wlan0 iface wlan0 inet dhcp
Warning: Don't 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.

# rc-service networking --quiet restart &


Perform sanity checks like ping and browsing. For issues related to name resolution, refer Networking page.

If all is well, 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

With the above configuration, udhcpc will only run once at boot. If the Wifi isn't available then, or the network changes after booting, udhcpc needs to be notified. You can automatically notify udhcpc of network changes by using a wpa_cli action file, such as the one installed by default at `/etc/wpa_supplicant/wpa_cli.sh`.

To manually start a wpa_cli daemon with an action file, use the `-a` option:

# wpa_cli -a /etc/wpa_supplicant/wpa_cli.sh


To do this automatically, use the `wpa_cli` service included in wpa_supplicant-openrc:

Contents of /etc/conf.d/wpa_cli

WPACLI_OPTS="-a /etc/wpa_supplicant/wpa_cli.sh"

# rc-update add wpa_cli boot

Troubleshooting

Check dmesg

Run dmesg and check for errors related to the wireless interface. Usually, dmesg gives maximum information related to network and all other hardware.

# dmesg

or

# dmesg

checking network cards

$ cat /proc/net/dev

lists the network interfaces that are detected. If the expected interfaces are not available, Check what network hardware chip you have using lspci or lsusb:

$ lspci -nn

$ lsusb

Refer hardware management, if the default outputs shown above lacks sufficient information.

Check what driver the card uses and modprobe it. Check that the card is in master mode. Check what driver you need on the b43 compatibility page

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 cards.

To check what broadcom chip you have using lspci:

$ lspci -nn -d 14e4:

B43

Download firmware cutter.

$ 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 $ 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.

wl

First install the software we need to build a driver^:

apk add git alpine-sdk linux-headers

Then install the driver build repo (this is archived, however it's legacy so that doesn't matter):

git clone https://github.com/antoineco/broadcom-wl cd broadcom-wl

Then follow the build instructions listed in the git repo:

make doas make install doas depmod -A doas modprobe wl

reboot and you have a working wl driver!

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:

~$ 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


See Also

Retrieved from "https://wiki.alpinelinux.org/w/index.php?title=Wi-Fi&oldid=27600"