How do I go about writing a dll for pinging?

Question

This question admittedly sounds stupid, however, I'm trying to create a dll for another application that I didn't build that only accepts unmanaged C/C++ dlls. This is for hooking into a game and pinging clients that connect to the game (the application I didn't build). I've been looking at tons and tons of stuff on google, but I can't find anything that seems to be the holy grail. 

Do I use ICMP or TCP for this? Is it possible to spam a client with ping requests and therefore be seen as a threat, or to accidentally do denial of service sort of attack on clients using ICMP?

Any help would be appreciated.