Re: IPMARK

[Michal Soltys <nozo@ziu.info>]

Jason Cosby wrote:
> All,
> 
> I see using IPMARK as the way to go, but am not clear how to put it 
> together. The documentation doesn't quite clear it up for me. Can 
> anyone help me get together a simple down and dirty script to do as I
>  described? Once I get the network under control a bit I will
> continue implementing proper QOS. If I don't get a handle on this
> soon I will be tarred, feathered, and thrown in the desert to rot
> (almost), so any help is GREATLY appreciated.
> 

You can as well use CLASSIFY target, instead of MARK+tc filter.

Example (pretty crude and simplified - there're many factors to consider
after all) of what you have in mind:


#adjust queue lengths in "pfifo" to your needs
#adjust interface name
eth=eth1

tc qdisc add dev $eth root handle 1:0 hfsc default 101
tc class add dev $eth parent 1:0 classid 1:1 hfsc ls m2 512kbps \
         ul m2 512kbps

#default queue
tc class add dev $eth parent 1:1 classid 1:101 hfsc rt m2 60kbps \
         ls m2 200kbps
tc qdisc add dev $eth handle 101:0 parent 1:101 pfifo limit 10

#client queues
tc class add dev $eth parent 1:1 classid 1:102 hfsc rt m2 400kbps \
         ls m2 400kbps
tc qdisc add dev $eth handle 102:0 parent 1:102 sfq limit 20 \
         perturb 10 quantum 1

iptables -t mangle -A FORWARD -o $eth -m iprange --src-range \
         192.168.1.6-192.168.1.40 -j CLASSIFY --set-class 1:102


The above will guarantee 60kbps for all the other traffic, 400kbps for
the clients, and divide any unused bandwidth in 1:2 ratio (in hfsc -
realtime guerantees use actual values, but linkshare criterion based on
ratios of values - 200:400 here). SFQ will take care of distributing the
bandwidth across all the clients. Check out recently added flow 
classifier to extend SFQ functionality similary to what was possible 
with ESFQ ( http://marc.info/?l=linux-netdev&m=120180241422360&w=2 ).

Alternatively - you could create 35 hfsc leaf classes in a loop, but
getting sizes of the leaf queues can become tricky (there may be
something I'm not aware of though), and SFQ seems like a much better 
thing (especially with mentioned above functionality extended by 'flow').

E.g. something along the lines of:

for i in `seq -w 6 1 40` ; do
         iptables -t mangle -A MARKCHAIN -s 192.168.1.1${i} \
                 -j CLASSIFY --set-class 1:1${i}
         tc class add dev $eth parent 1:1 classid 1:1${i} \
                 hfsc sc m2 10000
         tc qdisc add dev $eth handle 1${i}:0 parent 1:1${i} \
                 pfifo limit 3
done

If you gonna read about traffic shaping, be sure to check out:

http://ace-host.stuart.id.au/russell/files/tc/doc/

It's the very good source of info for u32 filter, among other things 
(old lartc faq is very innacurate here).