USB tethering allows users to use their phone's WiFi or WWAN interface
as an access point for the device they connect the phone with over USB.
This way, they can use their data plan with a laptop or desktop when
regular Internet access is absent.
Configure NetworkManager to manage the usb0 iface from initfs so users
can configure it in GNOME Settings or KDE. Include a NetworkManager
dispatcher script as well to handle postmarketOS' setup with unudhcpd as
we want to provide an SSH login over USB when tethering is disabled. If
tethering is enabled, unudhpcd is stopped and its functionality is taken
over by NetworkManager through an instance of dnsmasq. NetworkManager
will also configure the necessary settings to allow IP forwarding and
firewall rules during tethering. Once disabled, NetworkManager cleans up
these settings and our dispatcher script starts unudhcpd again.
Due to upstream changes, NetworkManager requires networkmanager-dnsmasq
subpackage as dependency as dnsmasq needs DBus support for
NetworkManager. Without it, NetworkManager will silently fail spawning
dnsmasq instances.
[ci:skip-build]: already built successfully in CI
4b92e922ef