Demon Hill is a cutsom proxy used in AD-style CTF's. It recives packets from clients and send the to the server applyng "filters" between the connection; it can also reload itself via command.
The filters are two lists (one for client data and one for server data) that contains functions that can operate on the data.
It is initialized as only a main that imports himself like a module, and with the command "r" in the cmd when running, can reimport itself and reload new patches and filters to new and old connections without disconnect none.