6.3 KiB
| title | subtitle | date | draft | author | tags | ||||
|---|---|---|---|---|---|---|---|---|---|
| GNU/Linux wireless networking like it's 2020 | How to add some systemd stuff inside your network configuration | 2020-07-14 | false | Wilfried |
|
From netcl to iwd 📡
ArchLinux is installed on my laptop (an XPS 15) since I got it from my job in
20171. 3 years ago, the cli tool distributed within the distribution was
netctl. It's an in-house ArchLinux
project allowing users to manage
networking. Overall, the tool does everything I need to get a
network connection up and running the way I need it. One of the main thing I
dislike about it is wifi-menu, a poorly design UI to search for wireless
access points.
Not so long ago a new challenger appeared : iwd. iNet Wireless Daemon
(iwd) is new wireless daemon for GNU/Linux (a standard tool, available on all
distros is better for this kind of tasks). Even if this project aims to
replace wpa_supplicant it can also replace netctl. If you think it's a
toy project from some random guy over the internet, bad news for you, that guy
is : Intel™. The fact that this program acts as a daemon means one standing
point : multiple clients will be available in the future and some well known
managers like network-manager might also use it. A default one comes with
the package as an interactive shell called iwctl, bye-bye wifi-menu !
To begin with iwd enable and start the service
systemctl enable --now iwd.service
and open the interactive shell
iwctl
then list all networks
[iwd] station wlan0 get-networks
Available networks
--------------------------------------------------------------------------------
Network name Security Signal
--------------------------------------------------------------------------------
ORTHANC psk ****
MINAS ITHIL psk ****
MINAS TIRITH psk ****
[iwd] station wlan0 connect ORTHANC
Enter the password if needed, it will be saved for later use (in
/var/lib/iwd) and check if everything is ok :
[iwd] station wlan0 show
Station: wlan0
--------------------------------------------------------------------------------
Settable Property Value
--------------------------------------------------------------------------------
Scanning no
State connected
Connected network ORTHANC
On reboot, iwd will try to reconnect to last used connection.
Adding some salty systemd stuff 🧂
Connected, sure, but what about an IP address 🤡 ? The first option is
obviously dhcpd but it scales poorly if you have to type it everytime you
connect to a network. Since version 0.19 iwd comes with a built-in DHCP
client to enable it just add
[General]
EnableNetworkConfiguration=true
in /etc/iwd/main.conf.
For some people it's good enough, but you know me, I like systemd a lot and
i'm already using systemd-networkd2 to create various kind of static network
interfaces and network connections.
To let systemd-networkd get DHCP configuration for you, ensure systemd-networkd is enabled
systemctl enable --now systemd-networkd.service
Now, add a .network file (in /etc/systemd/network) for the main wifi interface
[Match]
Name=wlan0
[Network]
DHCP=yes
The match section is used to identify the interface by name, the network one ensures that this configuration comes from DHCP.
Now that everything is setup, systemd-networkd will get configuration for this
interface when requested by changes on wifi interface from iwctl.
More salt with systemd-resolved 👺
In order to piss off the ones who hate systemd, I decided to add
systemd-resolved into the mix.
systemd-resolved is a systemd subservice providing a local DNS system with
caching, DNSSEC or the cool new kid : DNS over
TLS.
As usual to enable it :
systemctl enable --now systemd-resolved.service
The common way to change the DNS configuration is the good old
/etc/resolv.conf file. With systemd-resolved the recommended and most
disruptive way is to symlink the generated stub file
/run/systemd/resolve/stub-resolv.conf to /etc/resolv.conf.
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0
search example.lan example.com
The stub file contains only the local DNS stub server from systemd-resolved (available on 127.0.0.53).
The main purpose of this server is a caching implementation avoiding useless DNS requests.
To get an idea of the number of requests where the cache is used, just check statistics
resolvectl statistics
DNSSEC supported by current servers: no
Transactions
Current Transactions: 0
Total Transactions: 8544
Cache
Current Cache Size: 65
Cache Hits: 2394
Cache Misses: 3939
To customize systemd-resolved configuration, just look at
systemd-revolved(8) and the config file in /etc/systemd/resolved.conf
(resolvctl with no argument can be used to get information about the
current configuration).
This is, in my opinion, the best networking config I ever have.
Happy systemding !