View source for Wifi SystemdNetworkd

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--> {{PageHeader|Wireless}} 
{{DocImage|category1=Yocto|category2=Debian}}[[Category:DART-MX8M]][[Category:DART-MX8M-MINI]][[Category:DART-MX8M-PLUS]] __toc__

= {{#var:HARDWARE_NAME}} Overview =

The {{#var:HARDWARE_NAME}} supports the following WiFi modules:

{| class="wikitable" 
|-
! Module
! Chipset
! Features
! Network Interface(s)
|-
| Sterling LWB
| Cypress CYW4343W
| 802.11 b/g/n
| wlan0
|-
| Sterling LWB5
| Cypress CYW43353
| 802.11 ac/a/b/g/n,
| wlan0
|-
{{#ifeq: {{#var:WIFI_IW612_SUPPORT}}|yes|
{{!}}-
{{!}} Murata LBEE5PL2DL
{{!}} NXP IW611
{{!}} 802.11 a/ac/ax/b/g/n
{{!}} wlan0, uap0, wfd0
{{!}}-
{{!}} Murata LBES5PL2EL
{{!}} NXP IW612
{{!}} 802.11 a/ac/ax/b/g/n, 802.15.4
{{!}} wlan0, uap0, wfd0
}}
|}

This guide demonstrates how to configure WiFi using systemd-networkd. It is important to use the correct network interface for the module assembled on your {{#var:HARDWARE_NAME}}.

= Managing WiFi using systemd-networkd =

systemd-networkd is a system daemon that manages network configurations. It detects and configures network devices as they appear.<br>
systemd-networkd's functionality can be useful for both wireless and wired networks.<br>
This guide describes how to use systemd-networkd to configure wireless networks.

== Enabling and disabling WiFi ==

To enable WiFi run
<pre>
# networkctl up wlan0
</pre>

To disable WiFi run
<pre>
# networkctl down wlan0
</pre>

== Configuring WiFi Client ==

=== Scanning for available WiFi APs ===

If WiFi is enabled you can get the list of available APs by running

<pre>
# iw dev wlan0 scan | grep SSID
</pre>

=== Connecting to a protected WiFi network ===

Create /etc/systemd/network/80-wifi-station.network as following:

<pre>
# cp /lib/systemd/network/80-wifi-station.network.example /etc/systemd/network/80-wifi-station.network
</pre>

Append the following content to /etc/systemd/network/80-wifi-station.network:

<pre>
"[DHCPv4]
"RouteMetric=9"
"[IPv6AcceptRA]"
"RouteMetric=9"
</pre>

Create /etc/wpa_supplicant/wpa_supplicant-wlan0.conf with the following content:

<pre>
"ctrl_interface=/var/run/wpa_supplicant"
"eapol_version=1"
"ap_scan=1"
"fast_reauth=1"
wpa_passphrase <SSID> <password>
</pre>

Restart the services

<pre>
# systemctl restart systemd-networkd.service
# systemctl restart wpa_supplicant@wlan0.service
</pre>

Wait a few seconds and than make sure wlan0 is up and connected to the AP

<pre>
# ifconfig wlan0
</pre>

== Configuring WiFi Access Point with Hostapd ==

hostapd is a versatile tool for setting up a WiFi access point and generally offers more options and flexibility compared to NetworkManager.<br>
For instance, hostapd enables the creation of a WiFi 6 access point, which is not currently possible with NetworkManager.<br>
udhcpd is a suitable option for providing DHCP services alongside hostapd. It's a lightweight DHCP server that can be easily integrated with hostapd.

=== Create /etc/hostapd.conf ===

The next step is to create /etc/hostapd.conf. The following table shows how to configure 802.11bgn, 802.11ac, and 802.11ax access points:

{| class="wikitable" 
|-
! Wi-Fi 2.4GHz (802.11bgn)<br>/etc/hostapd.conf 
! Wi-Fi 5 (802.11ac)<br>/etc/hostapd.conf 
! Wi-Fi 6 (802.11ax)<br>/etc/hostapd.conf 
|-
| {{HOSTAPD_BGN}}
| {{HOSTAPD_AC}}
| {{HOSTAPD_AX}}
|}

Add the Control interface directory and group to /etc/hostapd.conf:

<pre>
# Control interface directory and group
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
</pre>

Note: When copying the text above, your file may contain zero width spaces at the end of each line (appearing as `^^k` in nano or hex `e2 80 8b` in hexdump). This will cause hostapd to fail. You can fix it by running:

 # sed 's/\xe2\x80\x8b//g' /etc/hostapd.conf > /etc/hostapd_cleaned.conf && mv /etc/hostapd_cleaned.conf /etc/hostapd.conf

=== Configure DHCP server ===

<pre>
# Sample udhcpd configuration file (/etc/udhcpd.conf)
# The start and end of the IP lease block
start 192.168.5.20 #default: 192.168.0.20
end 192.168.5.25 #default: 192.168.0.254
# The interface that udhcpd will use
interface uap0

opt dns 8.8.8.8 8.8.4.4 # public google dns servers
option subnet 255.255.255.0
opt router 192.168.5.1
option lease 864000 # 10 days of seconds
</pre>

Then, assign uap0 an ip and start hostapd and udhcpd:

<pre>
ifconfig uap0 192.168.5.1
sleep 1
systemctl restart hostapd
sleep 1
udhcpd /etc/udhcpd.conf
</pre>

At this point, devices can connect and dhcp an ip address using the access point on uap0.

=== Optionally configure NAT between uap0 and eth0: ===

<pre>
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
# iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
# iptables -A FORWARD -i uap0 -o eth0 -j ACCEPT
</pre>

and allow ip forwarding:
<pre>
echo 1 > /proc/sys/net/ipv4/ip_forward
echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
</pre>

Now, devices connecting to the access point on uap0 will have network access through eth0.

== Sterling LWB/LWB5 WiFi STA/AP concurrency ==
To get the WiFi module to work in concurrent AP-STA mode on the Sterling LWB/LWB5, a virtual wireless interface is required.

This can be achieved creating a virtual ''uap0'' interface, running

 # iw dev wlan0 interface add uap0 type __ap

STA setup can be managed simply following the steps described in [[Wifi_SystemdNetworkd#Configuring_WiFi_Client|Configuring WiFi Client]] section.

AP setup can be managed following the steps described in [[Wifi_SystemdNetworkd#Configuring_WiFi_Access_Point_With_Hostapd|Configuring WiFi Access Point]] section, but when creating the access point, be careful to use uap0 instead of wlan0.

=== Notes ===
The ''iw'' command (used to create the virtual uap0 interface) does not create permanent changes: we suggest to introduce it in the variscite-wifi script (located in /etc/wifi for latest releases), when checking for the wlan0 existance, something like
<syntaxhighlight lang="bash">
if [ -d /sys/class/net/wlan0 ]; then
	# create uap0 interface
	iw dev wlan0 interface add uap0 type __ap
	return 0
else
	...
</syntaxhighlight>
Also, in the same file, just before shutting down wlan0, you may want to delete this virtual interface, something like
<syntaxhighlight lang="bash">
...
# delete uap0 interface
iw dev uap0 del
# Down WIFI
wifi_down
...
</syntaxhighlight>

=== Limitations ===
By HW design, Sterling-LWB/LWB5 WiFi modules provide a single channel tuner.

AP-STA operations are possible, but the local AP channel is actually the one negotiated between the local client and the remote AP.