From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH] iptables: use skb->len for accounting
Date: Fri, 23 Jul 2010 08:58:22 +0200
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Cc: Patrick McHardy <kaber@trash.net>,
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To: Changli Gao <xiaosuo@gmail.com>
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Le vendredi 23 juillet 2010 =C3=A0 14:47 +0800, Changli Gao a =C3=A9cri=
t :
> On Fri, Jul 23, 2010 at 2:29 PM, Eric Dumazet <eric.dumazet@gmail.com=
> wrote:
> > Le vendredi 23 juillet 2010 =C3=A0 11:34 +0800, Changli Gao a =C3=A9=
crit :
> >> iptables: use skb->len for accounting
> >>
> >> use skb->len for accounting as xt_quota does.
> >>
> >
> > Why ?
> >
> > This is a gratuitous change, unless you have very strong arguments.
> >
> > xt_quota is an exception, dont change all others because of it !
>=20
> exception ? Why ?

Because it handles all protocols...

So skb->len is a shortcut, an approximation if you want.

At IPV4 level, ip->tot_len is an exact value.