Re: [LARTC] u32 filter won't match

From: Stef Coene <stef.coene@docum.org>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] u32 filter won't match
Date: Sun, 23 Nov 2003 10:16:26 +0000	[thread overview]
Message-ID: <marc-lartc-106958467622902@msgid-missing> (raw)
In-Reply-To: <marc-lartc-106956238912741@msgid-missing>

On Sunday 23 November 2003 05:03, Fredrik Tolf wrote:
> Hi!
>
> I really need help with a u32 filter that won't match what I think I'm
> telling it to. The situation is that I have set up an internal
> computer to change the TOS value of packets sent by certain processes
> to 0x1E (If anyone known of a better way to mark packets, please tell
> me. I would love to find some module that adds an IP option with UIDs
> and GIDs to the packets - does anyone know if such a module already
> exists?), and I want my router to deprioritize them. I also want to
> limit my outbound bandwidth to 750kbit overall. So anyway, this is my
> qdisc setup:
>
> tc qdisc add dev eth1 root handle 1: cbq bandwidth 10mbit \
>     avpkt 1000 rate 750kbit cell 8
> tc qdisc add dev eth1 parent 1: handle 2: prio bands 4
> tc qdisc add dev eth1 parent 2:1 handle 3: sfq perturb 10
> tc qdisc add dev eth1 parent 2:2 handle 4: sfq perturb 10
> tc qdisc add dev eth1 parent 2:3 handle 5: sfq perturb 10
> tc qdisc add dev eth1 parent 2:4 handle 6: sfq perturb 5
>
> So far so good. All packets go to the right qdisc among 3: - 5: (As
> seen with "tc -s qdisc ls"). However, when I add the filter to make
> packets with TOS 0x1E go to 6:, I set it up like this:
>
> tc filter add dev eth1 parent 1: protocol ip prio 1 \
>     u32 match ip tos 0x1e 0xff flowid 6:
You are making a lot of errors.  You add a root cbq qdisc, that's fine, but 
you need to add a class if you want to bound it to a rate.  
If you add a filter to a qdisc, it has to point to a class of that qdisc.  Not 
to an other class.

> I am under the impression that it should be done like that. However,
> that filter simply doesn't match the packets. I have tried some
> combinations, like setting the flowid to 2:4 instead or using parent
> 2:. (The strange thing is that when I used "parent 2:", no filter was
> added at all... What's up with that?) 
Try 
tc -s -d filter show dev eth1 parent 2:

Stef

-- 
stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.openprojects.net

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