From owner-svn-src-head@freebsd.org Mon Jul 30 04:20:50 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EF7D010497E9; Mon, 30 Jul 2018 04:20:49 +0000 (UTC) (envelope-from lidl@pix.net) Received: from hydra.pix.net (hydra.pix.net [IPv6:2001:470:e254::4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.pix.net", Issuer "Pix.Com Technologies LLC CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 85D8286B86; Mon, 30 Jul 2018 04:20:49 +0000 (UTC) (envelope-from lidl@pix.net) Received: from torb.pix.net (torb.pix.net [192.168.16.32]) (authenticated bits=0) by hydra.pix.net (8.15.2/8.15.2) with ESMTPA id w6U4KmMg078444; Mon, 30 Jul 2018 00:20:48 -0400 (EDT) (envelope-from lidl@pix.net) Subject: Re: svn commit: r336465 - in head/sys/netinet: . tcp_stacks To: Maxim Konovalov , Michael Tuexen Cc: Randall Stewart , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201807182249.w6IMns6D076446@repo.freebsd.org> <7FC7DAA2-9B03-4D89-A878-7706EDE4294A@macmic.franken.de> From: Kurt Lidl Message-ID: <91467128-5e84-6518-87ce-5374d410e1af@pix.net> Date: Mon, 30 Jul 2018 00:20:48 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.27 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: Mon, 30 Jul 2018 04:20:50 -0000 On 7/19/18 9:18 AM, Maxim Konovalov wrote: > On Thu, 19 Jul 2018, 08:09-0400, Michael Tuexen wrote: > >>> On 19. Jul 2018, at 03:12, Maxim Konovalov wrote: >>> >>> Hi Randall, >>> >>> On Wed, 18 Jul 2018, 22:49-0000, Randall Stewart wrote: >>> >>>> Author: rrs >>>> Date: Wed Jul 18 22:49:53 2018 >>>> New Revision: 336465 >>>> URL: https://svnweb.freebsd.org/changeset/base/336465 >>>> >>>> Log: >>>> Bump the ICMP echo limits to match the RFC >>>> >>> [...] >>> >>> Just wonder, are there any practical reasons to do that? >> In case you send encapsulated packets triggering an ICMP message >> you actually need more than the 8 bytes which are currently >> reflected. > > OK, let me rephrase: why do you need more than 8 bytes? It looks like > it has been working rather well for 20+ years. Coming late to the game (I was away for vacation)... It's handy to have more than 8 bytes of returned payload for ICMP packets to allow for more sophisticated network health scanning metrics. Back when I worked at UUNET, we used the ICMP ECHO REQUEST packets to carry accurate timestamps for monitoring dispersion of multicast datagrams to select hosts. I know, ICMP ECHO REQUEST packets have required all payload to be returned since at least RFC 1712 - so it's not exactly the same as what is being change here... I imagine that a similar generic treatment of payload data for other ICMP type message might be handy too. -Kurt