It sounds pretty straightforward for WiFi: you have two devices connected to WiFi on the same network. These two devices can broadcast to let each other know th

It sounds pretty straightforward for WiFi: you have two devices connected to WiFi on the same network. These two devices can broadcast to let each other know that there is someone else there. After that, the IPs are known and devices can talk to each other. There is nothing platform specific in this model: standard UDP and TCP, nothing more than that. I am not familiar with BT protocol so I can't comment on how it is done with BT.