Seeking FOSS licensing software

It doesn't have to be uncrackable, just enough to dissuade casual attempts at hacking.

FOSS - usable in commercial projects.

Limit number of consecutive sessions.

I have my own ideas as to how to code it simply. But why reinvent the wheel?

Edit: To limit the number of consecutive session I was thinking of a simple counter in the databse (obfuscated somehow), which increments on login and decrements on logout. The tricky part is when someone closes the 开发者_开发技巧browser (and their session) without loggin out.

I can't even begin to imagine why FOSS licensing software would exist, this is exactly the kind of anti-feature that the whole FOSS movement was created to work against. I will be highly surprised and my monocle will pop off my face if I learn that such a thing exists.