hashlimit performance (--hashlimit-htable-size value)

hashlimit performance (--hashlimit-htable-size value)

[Marco Padovan]

Hi,

how far can I push --hashlimit-htable-max size?

I did some tests with 262144:
-m hashlimit --hashlimit-mode srcip --hashlimit-name testlimiter
--hashlimit 1/s --hashlimit-burst 10 --hashlimit-htable-size 4096
--hashlimit-htable-max 262144 -j RETURN

but it wasn't holding:

xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:05 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:10 white kernel: net_ratelimit: 239072 callbacks suppressed
xxxx:11:10 white kernel: xt_hashlimit: max count of 262144 reached
xxxx:11:10 white kernel: xt_hashlimit: max count of 262144 reached

Am I doing it wrong?

Should I set hashlimit-htable-size = hashlimit-htable-max in order to
achieve better performance and map 1 IP to 1 bucket?

I even tried to take a look at the module source code but I'm not
skilled enough to fully understand it :D

I'm asking if there is some in-depth documentation about how
hashlimit-htable-max interact with the other
parameters(--hashlimit-htable-expire & --hashlimit-htable-gcinterval) in
order to handle high traffic flows or if anyone got real world
experience taking hashlimit to the limit :)

Thank you