From owner-freebsd-net@FreeBSD.ORG Thu May 27 07:12:19 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 73E7216A4CE; Thu, 27 May 2004 07:12:19 -0700 (PDT) Received: from comp.chem.msu.su (comp.chem.msu.su [158.250.32.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4AE2B43D1D; Thu, 27 May 2004 07:12:16 -0700 (PDT) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (localhost [127.0.0.1]) by comp.chem.msu.su (8.12.9p2/8.12.9) with ESMTP id i4REAv3F033941; Thu, 27 May 2004 18:10:57 +0400 (MSD) (envelope-from yar@comp.chem.msu.su) Received: (from yar@localhost) by comp.chem.msu.su (8.12.9p2/8.12.9/Submit) id i4REAuFR033939; Thu, 27 May 2004 18:10:56 +0400 (MSD) (envelope-from yar) Date: Thu, 27 May 2004 18:10:55 +0400 From: Yar Tikhiy To: Gleb Smirnoff Message-ID: <20040527141055.GA32704@comp.chem.msu.su> References: <200405251449.i4PEnkIa098672@repoman.freebsd.org> <20040525164251.GA3245@ip.net.ua> <20040525173458.GA18554@comp.chem.msu.su> <20040525184757.GA5546@ip.net.ua> <20040526032055.GA42697@comp.chem.msu.su> <20040526064152.GD24738@cell.sick.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040526064152.GD24738@cell.sick.ru> User-Agent: Mutt/1.5.6i cc: net@freebsd.org Subject: VLAN_MTU (was Re: cvs commit: src/sys/dev/fxp if_fxp.c if_fxpvar.h) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 May 2004 14:12:19 -0000 [moving the discussion from the cvs lists to -net] On Wed, May 26, 2004 at 10:41:52AM +0400, Gleb Smirnoff wrote: > > Y> ng_vlan(4) could send a control command to ng_ether(4) instructing > Y> the latter to increment the VLAN counter on the Ethernet interface > Y> and toggle VLAN_MTU on if the counter value became equal to 1. > > Two comments: > > 1) Just note that it should increment VLAN counter on creating of > any new VLAN hook. > 2) There may be some itermediate nodes between ng_ether and ng_vlan, > e.g. ng_tee(4), ng_etf(4), any custom traffic shaping or accounting > node. > > Two deal with second issue some new mechanism should be introduced in netgraph, > e.g. "broadcast" messages, which go down a hook spreading across all nodes, > and only nodes with appropriate cookie will see this message delivered. > > Y> Another way I see is to drop automatic fiddling with VLAN_MTU in > Y> the first place and implement an option for ifconfig(8) so that a > Y> user/admin can control the capability WRT a particular case, e.g., > Y> disable it if a NIC displays erroneous behaviour in long frame mode. > > From my point of view this is a good idea. The longer I've been thinking of the issue, the more I'm inclined to take the latter path. I believe that it would conform to the good tradition of Unix to offer a user as much control as possible and avoid doing "automagic" tricks behind user's back. Therefore I'd like to ask the community: Would anybody mind if vlan(4) gave up playing with VLAN_MTU on parent interfaces while a new option to ifconfig(8), say `vlanmtu', was introduced so that a user could control the feature manually? -- Yar