Messages in this thread | | | Date | Tue, 27 Sep 2022 14:32:25 -0700 | From | Jakub Kicinski <> | Subject | Re: [PATCH v2 net-next 01/12] net/sched: taprio: allow user input of per-tc max SDU |
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On Tue, 27 Sep 2022 21:23:19 +0000 Vladimir Oltean wrote: > On Tue, Sep 27, 2022 at 11:27:10AM -0700, Jakub Kicinski wrote: > > I know, that's what I expected you'd say :( > > You'd need a reverse parser which is a PITA to do unless you have > > clearly specified bindings. > > I think you're underestimating the problem, it's worse than PITA. My A > still hurts and yet I couldn't find any way in which reverse parsing the > bad netlink attribute is in any way practical in iproute2, other than > doing it to prove a point that it's possible.
Yup, iproute2 does not have policy tables, so it's hard.
Once you have tables like this:
https://github.com/kuba-moo/ynl/blob/main/tools/net/ynl/generated/ethtool-user.c#L22
all linking up the types, it's fairly easy to reverse parse:
https://github.com/kuba-moo/ynl/blob/main/tools/net/ynl/lib/ynl.c#L75
Admittedly I haven't added parsing of the bounds yet so it'd just say "invalid argument .bla.something" not "argument out of range .bla.something (is: X, range N-M)" but that's just typing.
> > I'd rather you kept the code as is than make precedent for adding both > > string and machine readable. If we do that people will try to stay on > > the safe side and always add both. > > > > The machine readable format is carries all the information you need. > > Nope, the question "What range?" still isn't answered via the machine > readable format. Just "What integer?".
Hm, doesn't NLMSGERR_ATTR_POLICY contain the bounds?
> > It's just the user space is not clever enough to read it which is, > > well, solvable. > > You should come work at NXP, we love people who keep a healthy dose of > unnecessary complexity in things :)
Ha! :D
> Sometimes, "not clever enough" is just fine.
Yup, go ahead with just the strings. "We'll get there" for the machine readable parsing, hopefully, once my YAML descriptions come...
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