From: Michal Soltys <soltys@ziu.info>
To: Julien Vehent <julien@linuxwall.info>
Cc: netfilter <netfilter@vger.kernel.org>
Subject: Re: SFQ hash question
Date: Fri, 11 Sep 2009 17:12:54 +0200 [thread overview]
Message-ID: <4AAA68F6.6020804@ziu.info> (raw)
In-Reply-To: <0322d4853c39162f0819db9263a210ed@localhost>
Julien Vehent wrote:
>
> OK for "h" and h2" before the "if", but what does this "if
> (!(iph->frag_off&htons(IP_MF|IP_OFFSET))" really does?
>
It checks whenever the packet is not a fragment. htons(IP_MF|IP_OFFSET)
functions as a mask which is and'ed with frag_off (which covers both fragment
offset and "more fragments" flag).
> And, also, I'm not sure about this: "h2 ^= *(((u32*)iph) + iph->ihl);"
>
> Does it XOR h2 with the first 32 bits of the L4 protocol header ?
>
Yes. Excluding ESP, it basically means source and destination port (if L3's payload
is not a fragment, thus the previous test).
Btw - if you need better control of what contributes to hash used by sfq, check out
flow filter:
http://marc.info/?l=linux-netdev&m=120180241422360&w=2
next prev parent reply other threads:[~2009-09-11 15:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-11 13:50 SFQ hash question Julien Vehent
2009-09-11 15:03 ` Julien Vehent
2009-09-11 15:12 ` Michal Soltys [this message]
[not found] ` <2643b2d5a75307da3d00e97e0245bcf9@localhost>
[not found] ` <4AAA70A4.8030707@ziu.info>
2009-09-11 15:53 ` Julien Vehent
2009-09-12 22:12 ` Michal Soltys
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