lsfcc is a compiler, of sorts, intended to produce programs suitable for use with the Linux Socket Filter out of a C-like toy language.
It's presently in a very crude state, but I have used it to construct marginally useful filters for use with rlinetd. Here's a theoretically useful example program for brief demonstration purposse.
#include <udp.h> if((udp[source] < 1024) && (udp[dest] < 1024)) accept; deny;
If you want a public place to vent your spleen about it, the best place is probably the rlinetd list, since that's about the only toy that you're likely to be using this with.