From owner-freebsd-transport@freebsd.org Sun Apr 18 14:50:32 2021 Return-Path: Delivered-To: freebsd-transport@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id E30775EB523 for ; Sun, 18 Apr 2021 14:50:32 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from mailman.nyi.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 4FNXtc64w3z3kHV for ; Sun, 18 Apr 2021 14:50:32 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id D0D675EB5A4; Sun, 18 Apr 2021 14:50:32 +0000 (UTC) Delivered-To: transport@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D09E95EB804 for ; Sun, 18 Apr 2021 14:50:32 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from drew.franken.de (mail-n.franken.de [193.175.24.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.franken.de", Issuer "Sectigo RSA Domain Validation Secure Server CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4FNXtc3bDZz3k71 for ; Sun, 18 Apr 2021 14:50:32 +0000 (UTC) (envelope-from tuexen@freebsd.org) Received: from mb.fritz.box (ip4d15f626.dynamic.kabel-deutschland.de [77.21.246.38]) (Authenticated sender: macmic) by mail-n.franken.de (Postfix) with ESMTPSA id 44A15734384BE; Sun, 18 Apr 2021 16:50:29 +0200 (CEST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\)) Subject: Re: TCP Fast Open From: Michael Tuexen In-Reply-To: <7c17539a-b50f-bf52-b55b-5d9b1cc3caad@wizmail.org> Date: Sun, 18 Apr 2021 16:50:28 +0200 Cc: "transport@freebsd.org" Content-Transfer-Encoding: quoted-printable Message-Id: References: <7c17539a-b50f-bf52-b55b-5d9b1cc3caad@wizmail.org> To: Jeremy Harris X-Mailer: Apple Mail (2.3654.60.0.2.21) X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=disabled version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mail-n.franken.de X-Rspamd-Queue-Id: 4FNXtc3bDZz3k71 X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-BeenThere: freebsd-transport@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussions of transport level network protocols in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Apr 2021 14:50:32 -0000 > On 18. Apr 2021, at 14:49, Jeremy Harris wrote: >=20 > Could I put in a request for better observability? That is, for > an application to be able to tell (for both client and server cases) > if TFO was not tried / requested successfully / used with no data / > used with data ? Sure. It is on my plate and tracked in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D242492 >=20 > There is partial observability currently, via sockopts TCP_FASTOPEN > and TCP_INFO... and they are unreliable. >=20 > [ I'll note here that Linux is no better ] >=20 >=20 > Also, a means for getting data on the SYN,ACK packet. Currently > AFAIK we cannot; we can send data from the server (under TFO) before > the ACK of the SYN,ACK but only as a separate packet. >=20 > The use case in mind is SMTP, which is a server-first protocol. > Whether or not the facility would have to restrict to preloaded data, > or could manage an application interaction, is up for argument. So what you have in mind is a client using TCP fastopen, which does not send user data with the SYN segment, but the server sending its banner with the SYN-ACK. Is that the use case you are referring to? If that is the case, can you add that description to PR 242492? Best regards Michael > --=20 > Cheers, > Jeremy > _______________________________________________ > freebsd-transport@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-transport > To unsubscribe, send any mail to = "freebsd-transport-unsubscribe@freebsd.org"