netdev - large divisor for flow classifier

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <4CB899F7.0@navigue.com>
Date:	Fri, 15 Oct 2010 14:14:15 -0400
From:	Jonathan Thibault <jonathan@...igue.com>
To:	Patrick McHardy <kaber@...sh.net>
CC:	netdev@...r.kernel.org
Subject: large divisor for flow classifier

 It appears that when setting a fairly large divisor on the flow classifier for sfq, traffic stops altogether.

On my machine, anything above divisor 2200 seems to stop all traffic.  If I want to be fair between hosts (but not flows) for a large network (say 6000 hosts), I run into problems.  Obviously the rates here are quite low but this is just an example.

I also tested on a real interface with the same results.

Example that works:

tc qdisc add dev ifb0 root handle 3: htb default 10
  tc class add dev ifb0 parent 3: classid 3:1 htb rate 80kbit
    tc class add dev ifb0 parent 3:1 classid 3:10 htb rate 80kbit
      tc qdisc add dev ifb0 parent 3:10 handle 310: sfq perturb 10
      tc filter add dev ifb0 parent 3: protocol all prio 1 u32 match mark 0x000 0xf00 flowid 3:10
      tc filter add dev ifb0 parent 310: protocol all handle 0x310 flow hash keys dst divisor 1024

Example that doesn't work:

tc qdisc add dev ifb0 root handle 3: htb default 10
  tc class add dev ifb0 parent 3: classid 3:1 htb rate 80kbit
    tc class add dev ifb0 parent 3:1 classid 3:10 htb rate 80kbit
      tc qdisc add dev ifb0 parent 3:10 handle 310: sfq perturb 10
      tc filter add dev ifb0 parent 3: protocol all prio 1 u32 match mark 0x000 0xf00 flowid 3:10
      tc filter add dev ifb0 parent 310: protocol all handle 0x310 flow hash keys dst divisor 6144

Jonathan
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html