From owner-freebsd-net@FreeBSD.ORG Wed Aug 19 19:34:07 2009 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9AA5D106568C for ; Wed, 19 Aug 2009 19:34:07 +0000 (UTC) (envelope-from julian@elischer.org) Received: from outT.internet-mail-service.net (outt.internet-mail-service.net [216.240.47.243]) by mx1.freebsd.org (Postfix) with ESMTP id 784D78FC52 for ; Wed, 19 Aug 2009 19:34:07 +0000 (UTC) Received: from idiom.com (mx0.idiom.com [216.240.32.160]) by out.internet-mail-service.net (Postfix) with ESMTP id C4D5096720; Wed, 19 Aug 2009 12:34:06 -0700 (PDT) X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e Received: from julian-mac.elischer.org (home.elischer.org [216.240.48.38]) by idiom.com (Postfix) with ESMTP id D6BDF2D6017; Wed, 19 Aug 2009 12:34:05 -0700 (PDT) Message-ID: <4A8C53AD.1040102@elischer.org> Date: Wed, 19 Aug 2009 12:34:05 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.22 (Macintosh/20090605) MIME-Version: 1.0 To: Barney Cordoba References: <121870.41829.qm@web63905.mail.re1.yahoo.com> In-Reply-To: <121870.41829.qm@web63905.mail.re1.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: pyunyh@gmail.com, David Christensen , d@delphij.net, "freebsd-net@freebsd.org" , Jack Vogel , Jack F Vogel , yongari@freebsd.org Subject: Re: [PATCH] Fix for e1000 (em/igb) NOARP issue [Was Re: em(4): sending ARP regardless of NOARP flag] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Aug 2009 19:34:07 -0000 Barney Cordoba wrote: > > --- On Tue, 8/18/09, Julian Elischer wrote: > >> From: Julian Elischer >> Subject: Re: [PATCH] Fix for e1000 (em/igb) NOARP issue [Was Re: em(4): sending ARP regardless of NOARP flag] >> To: d@delphij.net >> Cc: pyunyh@gmail.com, "Barney Cordoba" , "David Christensen" , "freebsd-net@freebsd.org" , "Jack Vogel" , "Jack F Vogel" , yongari@freebsd.org >> Date: Tuesday, August 18, 2009, 6:55 PM >> Xin LI wrote: >>> -----BEGIN PGP SIGNED MESSAGE----- >>> Hash: SHA1 >>> >>> Barney Cordoba wrote: >>>> --- On Tue, 8/18/09, Pyun YongHyeon >> wrote: >>>>> From: Pyun YongHyeon >>>>> Subject: Re: [PATCH] Fix for e1000 (em/igb) >> NOARP issue [Was Re: em(4): sending ARP regardless of NOARP >> flag] >>>>> To: "Xin LI" >>>>> Cc: "Barney Cordoba" , >> "David Christensen" , >> "d@delphij..net" >> , >> "freebsd-net@freebsd.org" >> , >> "Jack Vogel" , >> "Jack F Vogel" , >> yongari@freebsd.org, >> "Julian Elischer" >>>>> Date: Tuesday, August 18, 2009, 5:49 PM >>>>> On Tue, Aug 18, 2009 at 02:03:37PM >>>>> -0700, Xin LI wrote: >>>>>> -----BEGIN PGP SIGNED MESSAGE----- >>>>>> Hash: SHA1 >>>>>> >>>>>> Hi, Jack, >>>>>> >>>>>> I have looked into the code history and >> found that >>>>> sys/dev/em/if_em.c,v >>>>>> 1.119 has introduced the arp_ifinit() call >> in order to >>>>> fix the problem >>>>>> that if_em won't send ARP when IP address >> is changed. >>>>>> I think we can further improve it as >> attached, say, >>>>> only do it when >>>>>> IFF_NOARP is not set. This should >> have no effect >>>>> for usual >>>>>> configuration but fix the problem when >> NOARP is the >>>>> desired behavior. >>>>> That change was introduced by me. I guess the >> root cause of >>>>> the >>>>> problem was long initialization time of >> hardware which in >>>>> turn >>>>> resulted in unbearable boot time when >> multiple-alias >>>>> addresses are >>>>> assigned to em(4). I don't remember >> details,though. >>>>> Since we're in the release cycle, the change >> you suggested >>>>> would be >>>>> quick fix for 8.0. I think em(4)/igb(4) should >> remove >>>>> SIOCSIFADDR >>>>> handling in driver which is layering >> violation. >>>> There are 2 kinds of programmers; those who do >> things "correctly', >>>> and those that do things that work. >>>> >>>> 99.99999% of the people will be using ARPs, so >> don't be silly and >>>> break the driver to solve a case that almost >> no-one cares about please. >> Cisco.Ironport runs 50% (2 out of 4) of their em >> interfaces in noarp >> mode. > > > Ah, are they running Jack's drivers unmodified? Seems unlikely. well they will be when they go to 8. They stay a revision or two back for stability reasons of course. why wouldn't they? > > NOARP does work. Does your network catch on fire if the interface sends > an ARP out? Does equipment start failing like dominos? well if your network sniffer started responding to arps, how would you feel? > > My point was don't make ARPs not work (the reason the "hack" is in > there is to make something work better) to preserve some fantasy of > "layering" that went out with the 8-track player. The check for > the NOARP flag is a better solution until the subsystem works the > way its supposed to work. > > Barney > > >