Q: systemd-networkd, wpa_supplicant and multiple USB Wifi adapters

[Johannes Ernst]

TL;DR:
Is there a way to run a single wpa_supplicant process that handles any kind of USB WiFi adapter in connection with systemd-networkd?

Long version:
I'm running systemd-networkd, which has made networking setup a lot easier for wired interfaces. I'd like to make it just as easy for WiFi interfaces, with a wildcard setup so it works for any kind of WiFi adapter (well, whose drivers are installed).

Here's my /etc/systemd/network/wifi.network:
   [Match]
   Name=wlp*

   [Network]
   DHCP=v4

This works with a named interface:
	systemctl start wpa_supplicant at wlp0s2f1u10

because that's the interface that my current WiFi USB adapter comes up on. This goes with /etc/wpa_supplicant/wpa_supplicant-wlp0s2f1u10.conf:

   ctrl_interface=/run/wpa_supplicant
   eapol_version=1
   ap_scan=1
   fast_reauth=1

   network={
       ssid="something"
       psk="else"
   }

There are two disadvantages:
* I have to plug my USB Wifi adapter into this exact USB port, otherwise the interface name changes and wpa_supplicant isn't running there
* if I plug in a different USB WiFi adapter (I have a zoo; nothing exceptional I guess, but it's a pain to keep track of which goes with which computer), the interface name may be different and wpa_supplicant isn't running there

I tried to run wpa_supplicant with the -u flag and without the interface ("systemctl start wpa_supplicant") but I never end up with an DHCP IP address after boot.

Is there a way to make this work?

See also related discussion on the Arch Linux forum: https://bbs.archlinux.org/viewtopic.php?pid=1492280

Thanks,



Johannes.