On Tue, Feb 01, 2011 at 08:26:53PM +0200, Volkan YAZICI wrote: > On Tue, 1 Feb 2011 13:15:15 -0500, Gregory Seidman writes: > > On Tue, Feb 01, 2011 at 07:40:06PM +0200, Volkan YAZICI wrote: > >> [...] > >> # while /bin/true; do \ > >> > iptables -A OUTPUT -i wlan0 -j DROP && \ > >> > usleep 100000 && \ > >> > iptables -D OUTPUT -i wlan0 -j DROP > >> > >> command (usleep is a small C program I wrote, see the attachment), > >> transfer hangs after some point and stops for ~30-40secs and finishes > >> when I stop the while loop. Do I miss anything? Any suggestions? > > > > Here you are interrupting for 100,000 usecs (which is 100msecs, I believe), > > but you don't sleep at all between interruptions in the while loop. That > > means that it only has the time between the execution of the iptables > > command at the end of the loop and the execution of the iptables command at > > the beginning of the loop to actually transmit any packets. It is > > unsurprising that it hangs. Make sure you sleep for a while after removing > > the iptables rule. > > Indeed, sleeping more than I want is what I try to avoid. In other > words, I'm inclined to believe that running iptables externally doesn't > provide an interruption mechanism in milli/microsecond granularity. Any > other suggestions?
Well, I suggested before that you look into the iptables code and make the system calls it does rather than executing it externally. > Regards. --Greg -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20110201183526.gi11...@anthropohedron.net
