Messages in this thread | | | Date | Mon, 17 Apr 2006 03:38:33 -0400 | From | George Nychis <> | Subject | want to randomly drop packets based on percent |
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Hey,
I'm using the 2.4.32 kernel with madwifi and iproute2 version 2-2.6.16-060323.tar.gz
I wanted to insert artificial packet loss based on a percent so i found: network emulab qdisc could do it, so i compiled support into the kernel and tried: tc qdisc change dev eth0 root netem loss .1%
however i keep getting the error RTNETLINK answer: Invalid argument
I am not sure how to go about solving this problem for now, so if anyone has any suggestions i'd greatly appreciate it.
I really only need to drop random packets being forwarded through ip_forward ... however randomly dropping any packet based on a % is sufficient so I figured netem would be great.
So in the meantime I figured I would try to insert packet loss in ip_forward.c by generating a random number and dropping based on that. I could goto drop; depending on the number in the function int ip_forward(struct sk_buff *skb)
But then I ran into the problem of properly seeding the random number generator... srand(time(0)) is one way... however time() returns seconds, therefore i would drop multiple packets in a single second if I used this method which is very undesirable. What is the proper way to generate a random number here?
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