All told, the entire stack is comfortably under 200 lines of code
I'm almost willing to bet that's not counting the number of lines of code needed for the additional layers of abstraction underneath. Unfortunately, we can't read more about those because all the vpri.org links seem to have 404'd since this was written 14 years ago.
...but I did find someone who looked at it in more detail, and it is not under 200 lines: