Le 15/08/13 04:46, Thor Lancelot Simon a écrit :
On Wed, Aug 14, 2013 at 06:43:23PM +0200, Jean-Yves Migeon wrote:Hi list! I am looking for a library or set of tools I can integrate in a project to "simulate" a typical network behavior: latency(ies), packet lossage, out of order sequence, etc.How can you do this using the public system call interface? TCP will obscure many or even all of the issues you describe above...
Indeed, I failed to give more details there: The targetted protocol (LCT) is UDP based, and tries to broadcast data over multicast channels.
Multicast tends to be unreliable once you go with high TTLs (latencies and out of order, duplication, even loss of paquets). That is the part I am trying to deal with.
Current concern is that the library has been developped under NetBSD, but it will be used under Linux, and probably FreeBSD too. And I would like to have a simple "make test" target that could at least confirm that the library behaves correctly, and that my future additions do not introduce regressions. I hunted one down lately that could have been spotted earlier if I had a simple test running.
FWIW, nothing prevent testing a userland TCP implementation too, except that the hooks would be elsewhere (*_input and *_output).
LCT runs above UDP, so hooking typical network syscalls looked like the best possible place.
-- Jean-Yves Migeon