[LARTC] How to mark and queue

[LARTC] How to mark and queue

[Josip]

<PRE>Hello!

I would like to set up a machine to introduce random (but controllable)
dropping of packets that are being forwarded.  I also need to classify the
traffic because I want some traffic shaping.  The obvious solution is to
QUEUE packets to user level and if they are ACCEPTed, put a MARK
(--set-mark) on them for classifying.  This would seem logical:

iptables -A FORWARD -j QUEUE -j MARK

Of course, it is not possible.  How do I do this than?  That is, how to do
it without using two identical rules, one with QUEUE action and another
with MARK action which does not seem to be a nice solution.

Thanks!
Josip


</PRE>

[LARTC] How to mark and queue

[bert]

<PRE>On Thu, Oct 19, 2000 at 10:15:28AM +0200, Josip Gracin wrote:
&gt;<i> Hello!
</I>&gt;<i> 
</I>&gt;<i> I would like to set up a machine to introduce random (but controllable)
</I>&gt;<i> dropping of packets that are being forwarded.  I also need to classify the
</I>
Try to make a u32 match on a part of the header that changes a lot. I
suspect the IP packet id would be a good candidate, but you need to make
sure that resends of the same packet do get through. If you match, route to
loopback.

&gt;<i> traffic because I want some traffic shaping.  The obvious solution is to
</I>&gt;<i> QUEUE packets to user level and if they are ACCEPTed, put a MARK
</I>&gt;<i> (--set-mark) on them for classifying.  This would seem logical:
</I>&gt;<i> 
</I>&gt;<i> iptables -A FORWARD -j QUEUE -j MARK
</I>&gt;<i> 
</I>&gt;<i> Of course, it is not possible.  How do I do this than?  That is, how to do
</I>&gt;<i> it without using two identical rules, one with QUEUE action and another
</I>&gt;<i> with MARK action which does not seem to be a nice solution.
</I>
Try asking the netfilter mailinglist.

Regards,

bert hubert

-- 
PowerDNS                     Versatile DNS Services  
Trilab                       The Technology People   
'SYN! .. SYN|ACK! .. ACK!' - the mating call of the internet


</PRE>

[LARTC] How to mark and queue

[Josip]

<PRE>Thanks for the reply!

bert hubert (<A HREF="mailto:ahu@ds9a.nl">ahu@ds9a.nl</A>) wrote:
&gt;<i> On Thu, Oct 19, 2000 at 10:15:28AM +0200, Josip Gracin wrote:
</I>&gt;<i> &gt; I would like to set up a machine to introduce random (but controllable)
</I>&gt;<i> &gt; dropping of packets that are being forwarded.  I also need to classify the
</I>&gt;<i> 
</I>&gt;<i> Try to make a u32 match on a part of the header that changes a lot. I
</I>
But than I would not be able to control the randomness of drops.  I need a
drop policy based on various stochastic functions.

&gt;<i> Try asking the netfilter mailinglist.
</I>
Oops, I thought this was a perfect list to ask the question.  Sorry, I'll
ask there.

Best regards,
Josip


</PRE>

[LARTC] How to mark and queue

[Josip]

<PRE>bert hubert (<A HREF="mailto:ahu@ds9a.nl">ahu@ds9a.nl</A>) wrote:
&gt;<i> You could also use RED or GRED with strange configuration values. RED also
</I>
I understand that what you are suggesting would be much better for router
that handles high volumes of traffic.  But, I will be using this for
simulating a *slow* and congested (WAN) link between several machines so
there won't be too much traffic and consequently the performance is not an
issue.

Best regards,
Josip



</PRE>

[LARTC] How to mark and queue

[bert]

<PRE>On Thu, Oct 19, 2000 at 01:42:29PM +0200, Josip Gracin wrote:

&gt;<i> &gt; Try to make a u32 match on a part of the header that changes a lot. I
</I>&gt;<i> 
</I>&gt;<i> But than I would not be able to control the randomness of drops.  I need a
</I>&gt;<i> drop policy based on various stochastic functions.
</I>
You could also use RED or GRED with strange configuration values. RED also
does random dropping of packets, but normally only when routing a lot of
traffic. You might be able to get it to drop in ways that please you.

&gt;<i> &gt; Try asking the netfilter mailinglist.
</I>&gt;<i> 
</I>&gt;<i> Oops, I thought this was a perfect list to ask the question.  Sorry, I'll
</I>&gt;<i> ask there.
</I>
For what you want, netfilter is suited best. 

Regards,

bert hubert

-- 
PowerDNS                     Versatile DNS Services  
Trilab                       The Technology People   
'SYN! .. SYN|ACK! .. ACK!' - the mating call of the internet


</PRE>