On Mon, 29 Aug 2016 06:53:53 -0400
Jamal Hadi Salim [off-list ref] wrote:

On 16-08-29 04:30 AM, Jesper Dangaard Brouer wrote:

quoted

Hi Jamal,

Can you please provide a simple "tc" command that implements "tc drop"?

Then, I'll add this to the series of tests I'm using for (what I call)
"zoom-in" benchmarking.
 

Thanks Jesper.

I've created a script called tc_ingress_drop.sh[1] which uses the
commands you provided below.  Now people can easily use this script to
perform the benchmark you were requesting ;-)

[1] https://github.com/netoptimizer/network-testing/blob/master/bin/tc_ingress_drop.sh

Example to enable dropping:

 $ ./tc_ingress_drop.sh --dev mlx5p2 --verbose
 # (Not root, running with sudo)
 # Flush existing ingress qdisc on device :mlx5p2
 tc qdisc del dev mlx5p2 ingress
 tc qdisc add dev mlx5p2 ingress
 # Simply drop all ingress packets on device: mlx5p2
 tc filter add dev mlx5p2 parent ffff: prio 2 protocol ip u32 match u32 0 0 flowid 1:1 action drop

Example to disable again:
 ./tc_ingress_drop.sh --dev mlx5p2 --flush

 

Something simple since this is done in ingress; lets say drop icmp
packets:

export ETH=eth0
export TC=/sbin/tc
#delete existing ingress qdisc - flushes all filters/actions
sudo $TC qdisc del dev $ETH ingress
#re-add ingress
sudo $TC qdisc add dev $ETH ingress
#
#simple rule to drop all icmp
sudo $TC filter add dev $ETH parent ffff: prio 4 protocol ip \
u32 match ip protocol 1 0xff flowid 1:1 \
action drop

# other type of filters if you want to compare instead of above
#
# a)drop all
sudo $TC filter add dev $ETH parent ffff: prio 2 protocol ip \
u32 match u32 0 0 flowid 1:1 \
action drop
#b) drop if src is XXX
sudo $TC filter add dev $ETH parent ffff: prio 2 protocol ip \
u32 match ip src 192.168.100.1 flowid 1:1 \
action drop

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer