[Cake] Does the latest cake support "tc filter"?

Toke Høiland-Jørgensen toke at toke.dk
Wed May 30 15:58:22 EDT 2018

Georgios Amanakis <gamanakis at gmail.com> writes:

>> Yes, the version submitted to upstream supports this. You can override
>> which tin packets goes in by setting skb->priority from a filter or
>> application (the major number needs to be set to the qdisc ID, and the
>> minor number becomes the tin to queue packets in).
> Toke could you give an example how to do this?
> I am trying to put all traffic into tin 0:
> #tc qdisc add dev enp1s0 root handle 8001 cake diffserv3 bandwidth 2mbit
> #tc filter add dev enp1s0 parent 8001: protocol all \
>               u32 match u32 0 0 \
>               action skbedit priority 8001:1
> However as soon as the second command is executed all traffic drops,
> and it only resumes once I remove the filter.
> What am I doing wrong?

Hmm, nothing apart from using the classifiers in an unexpected (by me)
way ;)

Basically, what is happening is that the skbedit filter doesn't do
classification. In which case Cake will cheerfully drop the packet.

I just pushed a change to the upstream-4.18 branch which reworks the
filter classification so it'll still hash packets if the filter doesn't
make a decision, and also moves the tin selection to after the filter
has run, to give priority selection a chance to work (even if the
packets had not been dropped, you wouldn't have gotten the result you
wanted, since the skb->priority field was checked before the filters we

Please see if that works better :)


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