It's possible to create an IPSec + firewall based on the Click Modular Router[0] and run this on top of Unikraft[1].

[0]: https://github.com/kohler/click/wiki/IPsecEncap (and other IPSec* elements)

[1]: https://github.com/unikraft/app-click

It could make for an interesting tutorial with a full Click-based IPSec router though! :)