How to coect an Ubuntu Touch device with the internet via a desktop PC?

Short version:

How to coect an Ubuntu Touch device with the internet via a (debian) desktop PC, while still enabling adb shell coections to the device?

Long version:

My (debian) desktop PC stands in an area with quite bad WLAN reception. However, sometimes I want to coect my Ubuntu tablet to the internet while having an adb-shell open at my PC, for example when setting up a libertine chroot.

Because the WLAN coection frequently is interrupted, I would prefer to coect to the internet via my (debian) PC which has a stable LAN coection. Note that the coection should not interfere with an adb-shell or an alternative has to be proposed, as otherwise I still would be unable to use a shell from the desktop PC while having good internet on the tablet.