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From: Dave Taht <dave.taht@gmail.com>
To: Cake List <cake@lists.bufferbloat.net>
Subject: [Cake] passing args to bpf programs
Date: Wed, 1 Aug 2018 09:22:41 -0700	[thread overview]
Message-ID: <CAA93jw4YyAfgyFX-6_HTMaCdhfsWVt=V3eQ5uUzH78WuunVLRw@mail.gmail.com> (raw)

this really isn't the right list for this... but I wanted to build on
the ack_filter bpf code I had, to create impairments, like dropping
acks every X packets, or randomly, or when a specific pattern is seen
(like timestamps or sack). This was sort of the reverse complement to
getting the cake ack-filter right, now that I know everything that can
go wrong...

I see I can return ACT_SHOT, so I can drop packets.

But what I can't quite figure out is how to pass args to an tc ebpf
program. Do I have to pass those via a file descriptor? A map
generated elsewhere? what? Sure as heck don't want to compile one
program per opt....

Simplest args would be:

max 16 - drop every 16th ack packet
random 24 - drop randomly between 0 24
match only certain flags

followed by more gnarly ones like:

miscalculate if I have a payload or not
drop sack
mangle timestamps

-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619

             reply	other threads:[~2018-08-01 16:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-01 16:22 Dave Taht [this message]
2018-08-01 16:35 ` Stephen Hemminger
2018-08-01 16:36 ` Dave Taht
2018-08-01 16:42   ` Jonathan Morton
2018-08-01 16:54     ` Dave Taht
2018-08-01 17:25       ` Dave Taht
2018-08-01 19:20         ` [Cake] codel in ebpf? Dave Taht
2018-08-02 20:04           ` Toke Høiland-Jørgensen
2018-08-03  0:22             ` Dave Taht
2018-08-03 10:19               ` Toke Høiland-Jørgensen

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