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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 9E8EFC43460 for ; Tue, 18 May 2021 17:45:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81CFD611AC for ; Tue, 18 May 2021 17:45:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351346AbhERRrL (ORCPT ); Tue, 18 May 2021 13:47:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351272AbhERRrG (ORCPT ); Tue, 18 May 2021 13:47:06 -0400 X-Greylist: delayed 430 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 18 May 2021 10:45:48 PDT Received: from drew.franken.de (drew.ipv6.franken.de [IPv6:2001:638:a02:a001:20e:cff:fe4a:feaa]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BB53C061573 for ; Tue, 18 May 2021 10:45:48 -0700 (PDT) Received: from smtpclient.apple (unknown [IPv6:2a02:8109:1140:c3d:e0c4:9f6d:2867:98f4]) (Authenticated sender: macmic) by drew.franken.de (Postfix) with ESMTPSA id E1DD07220BFA5; Tue, 18 May 2021 19:38:30 +0200 (CEST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.80.0.2.43\)) Subject: Re: add SPP_PLPMTUD_ENABLE/DISABLE flag for spp_flags From: Michael Tuexen In-Reply-To: Date: Tue, 18 May 2021 19:38:27 +0200 Cc: "linux-sctp @ vger . kernel . org" , Marcelo Ricardo Leitner Content-Transfer-Encoding: 7bit Message-Id: <81B0ED00-D281-445B-83C7-7BE65DC0FD8E@freebsd.org> References: To: Xin Long X-Mailer: Apple Mail (2.3654.80.0.2.43) Precedence: bulk List-ID: X-Mailing-List: linux-sctp@vger.kernel.org > On 18. May 2021, at 18:43, Xin Long wrote: > > Hi, Michael, > > We're implementing RFC8899 (PLPMTUD) on Linux SCTP recently, > and to make this be controlled by setsockopt with > SCTP_PEER_ADDR_PARAMS, as in > > https://datatracker.ietf.org/doc/html/rfc6458#section-8.1.12: > > we need another two flags to add for spp_flags: > > SPP_PLPMTUD_ENABLE > SPP_PLPMTUD_DISABLE > > Do you think it makes sense? if yes, does the RFC6458 need to update? > if not, do you have a better suggestion for it? It is great new that you want to implement RFC 8899. I plan to do the same for the FreeBSD stack. In my view, RFC 8899 is the right way to implement PMTU discovery. So I will just use the SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE. I don't think that the user needs to control which method is used. I you want to support multiple versions, I would make that controllable via a sysctl variable. But I think for FreeBSD, support for RFC 8899 will be the only way of doing PMTU discovery. There might be multiple choices for details like how to do the searching, how long to wait for some events. These will be controllable via sysctl. So in my view, there is no need to extend the socket API. What do you think? Best regards Michael > > Thanks.