This script is designed for QubesOS. It allows the user to "easily" prioritise the network traffic of certain VMs. It works by setting the DSCP code point for outgoing traffic in a VM and processing it in ProxyVMs. VMs with a more critical traffic class have their traffic handled first, then VMs with a lower class. The script allows for 5 traffic classes by default, but this could be changed without much effort. The tc script takes care of prioritisation, while the mangle script tags VMs' traffic with the correct DSCP field based on the vm-config.dscp feature.

1. Download all the .sh and .service files from this repo.

2. Copy qubes-qos-mangle.sh and qubes-qos-mangle.service to the TemplateVMs of VMs whose traffic you want to (de-)prioritise. The .sh file should go to /usr/bin/, the .service file should go to /etc/systemd/system.

3. Make sure /usr/bin/qubes-qos-mangle.sh is executable (sudo chmod +x /usr/bin/qubes-qos-mangle.sh).

4. Enable the service in the TemplateVMs (sudo systemctl daemon-reload; sudo systemctl enable qubes-qos-mangle)

5. Copy qubes-qos-tc.sh and qubes-qos-tc.service to the TemplateVMs of your ProxyVMs (so of sys-firewall, etc.). (This can also just be all TemplateVMs, as the script will exit if it's not running inside a ProxyVM). The .sh file should go to /usr/bin/, the .service file should go to /etc/systemd/system.

6. Make sure /usr/bin/qubes-qos-tc.sh is executable (sudo chmod +x /usr/bin/qubes-qos-tc.sh).

7. Enable the service in the TemplateVMs (sudo systemctl daemon-reload; sudo systemctl enable qubes-qos-tc)

8. Apply priorities to VMs. For each VM you want to change the traffic priority of, execute this in dom0: qvm-features VMNAME vm-config.dscp CLASS.

CLASS can be one of:

• ef

• cs5

• cs0

• cs2

• cs1

The ef class is the highest priority, the cs1 class is the lowest priority. The cs0 class is also the default one, so you don't really need to set it on VMs explicitly. You'll most probably want ef or cs5 for real-time audio/video conversations and cs1 for very background tasks, like non-priority file sync.

The DSCP field gets reset when it passes through a VPN qube. This can be worked around in the following ways:

1. Use the OpenVPN passtos option to preserve the field

2. Perform some nftables black magic to achieve the same for Wireguard

3. Prioritise the traffic of the whole VPN qube as well as inside. The traffic entering the qube will get handled by the tc script, and the traffic leaving the qube will have a static DSCP value set by the mangle script.

See the qubes-utils repo for links to other utilities I've written for Qubes.

This project is licensed under the AGPL-3.0-or-later.