From owner-svn-src-head@FreeBSD.ORG Fri Mar 12 08:45:00 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CFDDB1065673; Fri, 12 Mar 2010 08:45:00 +0000 (UTC) (envelope-from julian@elischer.org) Received: from out-0.mx.aerioconnect.net (outf.internet-mail-service.net [216.240.47.229]) by mx1.freebsd.org (Postfix) with ESMTP id A5E848FC1A; Fri, 12 Mar 2010 08:45:00 +0000 (UTC) Received: from idiom.com (postfix@mx0.idiom.com [216.240.32.160]) by out-0.mx.aerioconnect.net (8.13.8/8.13.8) with ESMTP id o2C8ixhB010093; Fri, 12 Mar 2010 00:44:59 -0800 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 (h-67-100-89-137.snfccasy.static.covad.net [67.100.89.137]) by idiom.com (Postfix) with ESMTP id 514FB2D601B; Fri, 12 Mar 2010 00:44:59 -0800 (PST) Message-ID: <4B99FF0A.5080504@elischer.org> Date: Fri, 12 Mar 2010 00:44:58 -0800 From: Julian Elischer User-Agent: Thunderbird 2.0.0.23 (Macintosh/20090812) MIME-Version: 1.0 To: "Robert N. M. Watson" References: <201003111756.o2BHukJu042449@svn.freebsd.org> <9ace436c1003111530s3bd0de9cq451671909fb6aa64@mail.gmail.com> <5ADB6F0D-11F1-4F9F-87A0-64F57063981E@freebsd.org> <9ace436c1003112352l3b2505ceq63d9c78954520497@mail.gmail.com> <9ace436c1003120011v3c627aadka2e57615ae01fe6f@mail.gmail.com> <8726950E-5110-4FE1-90BB-B4205D637764@freebsd.org> <9ace436c1003120030m39f518basc77c7cff40299008@mail.gmail.com> <4B99FE46.6090001@elischer.org> In-Reply-To: <4B99FE46.6090001@elischer.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.67 on 216.240.47.51 Cc: svn-src-head@freebsd.org, Qing Li , svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r205024 - head/sys/net X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Mar 2010 08:45:00 -0000 Julian Elischer wrote: > Robert N. M. Watson wrote: >>>> >>>> Today, we support three link state values: >>>> >>>> 170 /* >>>> 171 * Values for if_link_state. >>>> 172 */ >>>> 173 #define LINK_STATE_UNKNOWN 0 /* link invalid/unknown */ >>>> 174 #define LINK_STATE_DOWN 1 /* link is down */ >>>> 175 #define LINK_STATE_UP 2 /* link is up */ >>>> >>>> I'm confused about Julian's proposal because it seems to me that we >>>> already know when a driver hasn't set or is unable to determine the >>>> link state: it will (should) be set to LINK_STATE_UNKNOWN by default. the question is whether there is any other meaning for this state. For example "I have not started up yet" >>>> >>>> So the only question we don't know the answer to, at run-time, is >>>> whether a driver may *ever* set the link state (i.e., it thinks it >>>> knows how to), and hence whether or not tools like dhclient should >>>> try to wait for that to happen. That is the problem that an >>>> interface capability would solve. >>>> >>>> For the purposes of ECMP, you just need to decide on your policy: >>>> map UNKNOWN to either UP or DOWN for your purposes. yes this is a good approach assuming that there is no other meaning. >>>> >>>> Robert