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Date: Sat, 9 Oct 2004 01:31:44 -0700
From: Luigi Rizzo <rizzo@icir.org>
To: Gleb Smirnoff <glebius@freebsd.org>,
	Giorgos Keramidas <keramida@freebsd.org>, freebsd-net@freebsd.org
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References: <20041008151515.GA3136@orion.daedalusnetworks.priv>
	<20041008203434.GA2770@cell.sick.ru>
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In-Reply-To: <20041008203434.GA2770@cell.sick.ru>;
	from glebius@freebsd.org on Sat, Oct 09, 2004 at 12:34:34AM +0400
Subject: Re: Calling m_pullup in ether_input
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On Sat, Oct 09, 2004 at 12:34:34AM +0400, Gleb Smirnoff wrote:
> On Fri, Oct 08, 2004 at 06:15:15PM +0300, Giorgos Keramidas wrote:
> G> In ether_input() we unconditionaly discard the mbufs whose m_len is less than
> G> ETHER_HDR_LEN.  A bit higher M_PKTHDR has been checked but the check made
> G> before discarding the frame doesn't pay attention to the m->m_pkthdr.len (the
> G> total packet length).
> 
> In my humble opinion, all Ethernet device drivers are intentionally written
> in such a way that they always pass an mbuf with contigous Ethernet header
> to ether_input().

actually, historically it wasn't always like this,
the API for ether_input()used to have the MAC header in a different
place, so the code giorgios refers to might be a leftover
from older times (still in 4.x)

cheers
luigi