From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] net: packet: option to only pass skb protocol
Date: Tue, 05 Jan 2010 15:51:50 -0800 (PST)
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From: "Chris Friesen" <cfriesen@nortel.com>
Date: Tue, 05 Jan 2010 16:13:29 -0600

> If SOCK_RAW packets are being sent, the protocol number is embedded in
> the packet data

Where exactly is that protocol value?  Not every link level protocol
is ethernet.

We support FDDI, HIPPI, wireless, VLAN, PPP, and a host of others.

So you can't know for sure unless you assume ethernet, which you
can't do.