Invading the Huum Uku WiFi Controller

Summary

I like saunas. For those unfamiliar with the concept, it is a hot room where you are occasionally beaten with tree-branches.You might have seen images like this: While in reality it is often more like thisAnyway, while looking for my very own financial burden to call home, I stumbled upon an offering which heavily promoted the fact that it had a sauna.Neat! Then I found out it had a remote capable controller. Even neater! The only issue is that it uses Huum’s proprietary cloud to do the remote controlling. And I very much dislike that. I mean it is fine for normal people, but I will not use any smartness on any device that I cannot control locally.But having remote control would still be nice, wouldn’t it?I’ve been thinking about this on-and-off for over a year now. It’d be oh so nice to arrive home from shit weather and be able to hop into a sauna that has already done the 1.5 hour long heat to 90 degrees.Theory#Searching the web I found that there’s an official-ish Home Assistant integration for Huum, but it requires logging in with the Huum app before use and basically only replicates the API calls the mobile app does. The integration seems to be built around the pyhuum library.But I don’t like that. I want my HA to control the controller directly.So I need to figure out how the controller speaks with the cloud. Or how the cloud speaks with the controller? In both cases the Controller has to be the one initiating the connection as otherwise I would have to allow the outside connection through the firewall. Which I have not (and will not) do. It is way too complicated for a regular person anyway.After consulting ChatGPT, we arrived at a solution: I was to use port mirroring on my switch to direct all the traffic generated main module to my laptop, where it could be Wiresharked. Crap, it doesn’t do eth, only Wi-Fi. (Uku WiFi…).I then had the idea of setting my laptop up as a hotspot to connect the controller to. Firstly, it isolates the controller traffic from...