From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 098E5C282C4 for ; Tue, 12 Feb 2019 03:40:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD34E2184A for ; Tue, 12 Feb 2019 03:40:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="OIBog3fj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727354AbfBLDkC (ORCPT ); Mon, 11 Feb 2019 22:40:02 -0500 Received: from mx.aristanetworks.com ([162.210.129.12]:42799 "EHLO prod-mx.aristanetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726226AbfBLDkC (ORCPT ); Mon, 11 Feb 2019 22:40:02 -0500 X-Greylist: delayed 495 seconds by postgrey-1.27 at vger.kernel.org; Mon, 11 Feb 2019 22:40:01 EST Received: from prod-mx.aristanetworks.com (localhost [127.0.0.1]) by prod-mx.aristanetworks.com (Postfix) with ESMTP id C50D5EA9; Mon, 11 Feb 2019 19:31:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=Arista-A; t=1549942305; bh=0FZpjISugGVHcgMxDZI8D90VWETxcCBzRqpXcnO9j4A=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=OIBog3fjMfi1IEsyMidTuucRrzSZOLU3lG8MACX63BMSm945TQFoVdiG+l/fGUVSu C1xsiVwM9Nc2PASo/+L7HNvA6P7O3ZSkc77blr7cjuOBdRgubnwyd+m74ZVX7B9iQI EALjAAB2m4ajLxAzod8gC1GQZVZM0Ll3XjiiP3uXf+9rS9Y76Do6BibOo2oQtTablP d/QkjU7I7sdRGOTy2n5evGPdp5+oHr7r58UiYw1Hp9iFI+z4ypKqCFPa3bGKJmcbKj IlO3QsXvNOt3wECNrbHQ2Dp7jVpumd6l18ILED1zUjr+9VPoGDdsfMH/MEPEvABfPD OSVv++mEf/ElQ== Received: from visor (unknown [172.20.208.17]) by prod-mx.aristanetworks.com (Postfix) with ESMTP id C2543EA8; Mon, 11 Feb 2019 19:31:45 -0800 (PST) Date: Mon, 11 Feb 2019 19:31:45 -0800 From: Ivan Delalande To: David Miller Cc: alin.nastac@gmail.com, netdev@vger.kernel.org Subject: Re: [PATCH] ipv6: fix icmp6_send() route lookup Message-ID: <20190212033145.GB28428@visor> References: <1549551931-11909-1-git-send-email-alin.nastac@gmail.com> <20190211.123818.1763509059512954986.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211.123818.1763509059512954986.davem@davemloft.net> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi David, On Mon, Feb 11, 2019 at 12:38:18PM -0800, David Miller wrote: > From: Alin Nastac > Date: Thu, 7 Feb 2019 16:05:31 +0100 > > > Original packet destination address must be used as saddr for the > > route lookup performed by icmp6_send() even when this address is > > not local. This fixes the IPv6 router ability to send back > > destination unreachable ICMPv6 errors for forwarded packets when > > the route toward the saddr of the original packet is source > > filtered (e.g. a default route with a "from PD" attribute, where > > PD is the delegated prefix). > > > > Signed-off-by: Alin Nastac > > Yes, but however this will change behavior for a lot of situations > not just the one you are interested in. > > The base ipv6_chk_addr() test has been there for more than a decade > and I'm not comfortable with changing this logic until I see you > write up a full audit of all of the use cases of icmp6_send() and > how they are impacted by your changes. For what it's worth, we also have 3 internal patches changing the selection of saddr in icmp6_send (to pick an address from the receiving interface in priority, or the most specific to the source address of the original packet, etc.) that we would like to submit in some form, but that would most likely break existing setups if enabled by default. Could we introduce a sysctl with a set of flags to enable the different behaviors from our patches and Alin's? Or any other configuration interface than sysctls if more appropriate. Thank you, -- Ivan Delalande Arista Networks