From owner-freebsd-hackers Tue Feb 29 10: 7:46 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by hub.freebsd.org (Postfix) with ESMTP id 2188D37BC61; Tue, 29 Feb 2000 10:07:41 -0800 (PST) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.9.3/8.9.3) id NAA57238; Tue, 29 Feb 2000 13:07:24 -0500 (EST) (envelope-from wollman) Date: Tue, 29 Feb 2000 13:07:24 -0500 (EST) From: Garrett Wollman Message-Id: <200002291807.NAA57238@khavrinen.lcs.mit.edu> To: Luigi Rizzo Cc: Julian Elischer , "Yevmenkin, Maksim N, CSCIO" , "'freebsd-current@freebsd.org'" , "'freebsd-hackers@freebsd.org'" Subject: Re: NETGRAPH (proposal. FINAL) In-Reply-To: <200002291759.SAA32145@info.iet.unipi.it> References: <38BC0745.2781E494@elischer.org> <200002291759.SAA32145@info.iet.unipi.it> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG < said: > can you clarify this ? Looong ago i used the '586 on a bridge and it did let > me write the MAC header... The 82586 has a mode bit which selects one of two possibilities: 1) The transmit command specifies the destination address and length/ethertype field; the source address is inserted by hardware. The receive buffer descriptor gets the source address and length/ethertype. 2) The transmit and receive buffers include a full Ethernet header. I can't say off the top of my head which the `ie' driver uses, but I would bet on (2) because that's easier for the driver to deal with. These sorts of controllers are the reason why ether_input takes the Ethernet header as a separate parameter. -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message