On 16-02-24 11:04 PM, John Fastabend wrote:
On 16-02-24 05:31 AM, Jamal Hadi Salim wrote:
I think this is absolutely necessary not only for performance of
reporting the rules back to software but if we don't do it generically
the driver will have to do it anyways because doing the inverse
transformation from hw implementation to u32 is really tricky and in
fact with hnodes and knodes there are multiple cls_u32 "programs" that
functionally are the same so we have no way to return what the user
actually programmed without it. Further eBPF (the next classifier I'm
working on) is even worse in this regard.
Ok, I guess there are multiple use cases for it ;->
Yes, with ebpf it will be worse because data and instructions are
inter- mingled (and our interest is in data only). Note:
Over the years this has been a big struggle for human
friendliness. I thought we didnt care about humans (as in automation)
but you are saying this will affect machines too ;-> We cant allow
that ;->
Note: You could decode u32 descriptions but it is an involved effort.
Example, see this feature in tc:
---
jhs@jhs1 tc -pretty filter ls dev $ETH parent ffff: protocol ip
filter pref 11 u32
filter pref 11 u32 fh 800: ht divisor 1
filter pref 11 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1
match IP src 10.0.0.130/32
action order 1: gact action drop
random type none pass val 0
index 1 ref 1 bind 1
----
See that "match" field reading in anglais? It requires more and more
additions of pretty printers that translate back.
What about adding some tag to allow for easy "babel translation"?
You can see my solution to
this "load in hardware" filter list in patch 4/4. See Jiri's comment
also on that and see if you agree.
Ok, will do.
cheers,
jamal
