# KnockKnock

A Windows Service for providing services on-demand.

## Overview

KnockKnock acts as a TCP proxy, accepting connections and then forwarding all
traffic between a client and upstream. It allows you to register commands to
run when the service is idle (no open connections) and active (incoming
connection(s)).

For example, when forwarding connections to a Hyper-V VM, you could suspend the
VM when there are no active connections, and resume it whenever a user attempts
to connect.

(Personally, this is how I use it--allowing my development VM to be suspended
automatically when I am not connected to it through RDP.)

## TODO / Limitations

This is basically the minimum viable app that solves my own problem. I slapped
it together in less than an hour.

Configuration is hardcoded: it only forwards :1234 -> 10.200.0.10:3306; it
always runs `SuspendVM` and `ResumeVM` against the `Debian` Hyper-V machine.
The socket code is kind of janky and some activity patterns will make it
explode.

It works for me to proxy a Microsoft Remote Desktop Connection session through
to a Hyper-V VM available on-demand.

## License

None. Do not redistribute.