From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] ipv6: export IP6_RT_PRIO_* to userland Date: Fri, 09 Nov 2012 14:05:29 -0500 (EST) Message-ID: <20121109.140529.897976987065389287.davem@davemloft.net> References: <20121105.124305.1002288640313724910.davem@davemloft.net> <5098127A.2040405@6wind.com> <509CD046.4060302@6wind.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: nicolas.dichtel@6wind.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:37696 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754024Ab2KITFh convert rfc822-to-8bit (ORCPT ); Fri, 9 Nov 2012 14:05:37 -0500 In-Reply-To: <509CD046.4060302@6wind.com> Sender: netdev-owner@vger.kernel.org List-ID: =46rom: Nicolas Dichtel Date: Fri, 09 Nov 2012 10:43:34 +0100 > Le 05/11/2012 20:24, Nicolas Dichtel a =E9crit : >> Le 05/11/2012 18:43, David Miller a =E9crit : >>> From: Nicolas Dichtel >>> Date: Mon, 05 Nov 2012 18:22:39 +0100 >>> >>>> Le 05/11/2012 18:00, David Miller a =E9crit : >>>>> From: Nicolas Dichtel >>>>> Date: Mon, 5 Nov 2012 16:28:18 +0100 >>>>> >>>>>> The kernel uses some default metric when routes are managed. For >>>>>> example, a >>>>>> static route added with a metric set to 0 is inserted in the ker= nel >>>>>> with >>>>>> metric 1024 (IP6_RT_PRIO_USER). >>>>>> It is useful for routing daemons to know these values, to be abl= e to >>>>>> set routes >>>>>> without interfering with what the kernel does. >>>>>> >>>>>> Signed-off-by: Nicolas Dichtel >>>>> >>>>> But these belong in the libc headers anyways. >>>>> >>>>> If we haven't provided them for so long, there's no real value of >>>>> adding them now. >>>>> >>>> But how can a daemon know which default values are used? If it wan= ts >>>> to add a route with metric =3D default + x, it should first add it= with >>>> metric =3D 0, check the result and then change the metric. >>> >>> What do we do on the ipv4 side and how do daemons cope in that >>> situation? >>> >> In IPv4, there is no such default metric. If you add a route with >> metric X, it >> remains X in the kernel, even if it's 0. > So we need to duplicate these values in the daemon? >=20 I'm without real internet access again for the past 2 days and simply too backlogged to even continue considering this issue. Please be patient.