Changing the network card driver to view and manipulate DSCP fields

Hello Reddit folks, in one o my University courses were dealing with diffserv and DSCP, today the teacher was talking about how the network card in your machine reads the fields of DSCP y IP headers using Wireshark to view...

At that moment and idea come to me, get the network card driver of my raspberry pi modify the source code for the DSCP or diffserv fields, and reload the driver into the Kernel, and for example mark all mi trafic with EF QoS (only for learning purposes) and show it in the class.

I have some knowledge in C, Linux, Networking but I need a starting point.

What should I do, where to start?

Thanks