Re: [LARTC] Structuring my shaping (fwd)

[Werner Almesberger <wa@almesberger.net>]

Hayden Myers wrote:
> I still don't understand how I can have multiple classes with a different
> filter for each class and then change one of the filters without blowing
> away the rest and having to have different priorities.  I'm shaping
> traffic between users so all filters should have the same priority.

First of all, you need to distinguish between filters and filter
elements. iproute2/tc makes this distinction rather vague, but
it's still there.

Filters are organized in lists at qdiscs or classes. Within each
such list, they are unique with respect to protocol and priority.
So you can't have multiple filters with the same priority. Note
that the filter priority has nothing to do with the priority of
the class in the qdisc.

If any of this sounds confusing to you, you may want to have a
quick look at one of the following two documents:
ftp://icaftp.epfl.ch/pub/people/almesber/pub/tcio-current.ps.gz
ftp://icaftp.epfl.ch/pub/people/almesber/junk/tc-04FEB2001-0.tar.gz
(just ignore the implementation bits).

You could parent filters at classes, but this still implies some
evaluation order, only that this order now depends on subtle
qdisc internals. Also, not all qdiscs let you do this (e.g.
sch_prio doesn't).

> Anybody else have problems changing/deleting filters?  I see some messages
> on the net but none have responses.  I saw something about u32h but his
> examples give me RTNETLINK: invalid argument messages.  This is beginning
> to irritate me highly.

Why don't you try to write a small script that produces the
problem, run it through tcsim (tcsim enables all traffic control
elements, so there are no problems with things being
unconfigured, modules missing, bad versions of iproute2/tc,
etc.), and if the problem still occurs with tcsim, post your
script to the list ?

To run your script with tcsim, simply do

$ tcsim -v
dev eth0  // or whatever device your script is for
tc qdisc add dev eth0 ...etc...
^D

- Werner

-- 
  _________________________________________________________________________
 / Werner Almesberger, Buenos Aires, Argentina         wa@almesberger.net /
/_http://www.almesberger.net/____________________________________________/
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