From owner-freebsd-net@freebsd.org Thu Jul 5 15:23:07 2018 Return-Path: Delivered-To: freebsd-net@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 8C9151032CD7 for ; Thu, 5 Jul 2018 15:23:07 +0000 (UTC) (envelope-from pieter@degoeje.nl) Received: from mo6-p00-ob.smtp.rzone.de (mo6-p00-ob.smtp.rzone.de [IPv6:2a01:238:20a:202:5300::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.smtp.rzone.de", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 0C32F823E6 for ; Thu, 5 Jul 2018 15:23:06 +0000 (UTC) (envelope-from pieter@degoeje.nl) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1530804184; s=strato-dkim-0002; d=degoeje.nl; h=Date:Message-ID:Subject:From:To:X-RZG-CLASS-ID:X-RZG-AUTH:From: Subject:Sender; bh=p2l1ISplQADFBPJJhdf8FGYhrZUSlqDrw167+QLu2sg=; b=a8fRrU0XYvorWkQRXLnWihQLoaKQaYGf8ZG5HYbJDj3RzKphU48JbbmBqhnZ7sRUeh 0e9pMqAVxzSG/vjEtYp91dXouxkcx+l75t/8Vt+kb8uEbf7Dxvq0w/m8+JNlgzMWNTAt T/5PM3Rjfk2gf7z/XLOTdjECqh7di7APqstVgjbUKas+4aLf1lRmQNvq58MX+kX0BK/T kZNQA1TYmPelv4Ws2GiHmibI9Z3UTEfXmRn1ZoN/9NktcV3w64yJi1TtkZ0EQ32jxPRx zuiFGjBz3PhV8fiKFHSiJ9qoIAaTHutlc0emaX48VcGH6jausqh4saGp/XXeDeXIgGVj kbiQ== X-RZG-AUTH: ":PGUBYUW6W/vjKUwSpXdHbXp/KlnzhfjpGaq9ccFSB01ZbYSz0XXyHEnBMb8k5m4K" X-RZG-CLASS-ID: mo00 Received: from [192.168.1.95] by smtp.strato.com (RZmta 43.12 AUTH) with ESMTPSA id j0271eu65FN45sd (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate) for ; Thu, 5 Jul 2018 17:23:04 +0200 (CEST) To: freebsd-net@freebsd.org From: Pieter de Goeje Subject: Does TCP_FASTOPEN actually work? Message-ID: <8f67a706-a650-bba2-a7dc-c25e676e1c97@degoeje.nl> Date: Thu, 5 Jul 2018 17:23:04 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: nl Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Jul 2018 15:23:07 -0000 I'm trying to test this new feature, but I have trouble getting the client to actually send a cached cookie. It keeps requesting new ones and as a consequence it never sends data in the initial SYN packet. Tcpdump shows that the server correctly replies to a cookie request with a cookie. Or am I misunderstanding how it should work and is the cookie cache per-process instead of system wide? I'm using the test programs from https://people.freebsd.org/~pkelsey/tfo-tools/ for this purpose. Server and client run on r335760 or later, with no changes to net.inet.tcp.fastopen except that server_enable was set to 1. Related issue is that TCP_FASTOPEN is currently undocumented in tcp(4). - Pieter