From owner-freebsd-net@freebsd.org Mon Mar 20 18:47:50 2017 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 59ABBD143FF for ; Mon, 20 Mar 2017 18:47:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 3ECBB1A5 for ; Mon, 20 Mar 2017 18:47:50 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id v2KIln9K041556 for ; Mon, 20 Mar 2017 18:47:50 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-net@FreeBSD.org Subject: [Bug 217637] One TCP connection accepted TWO times Date: Mon, 20 Mar 2017 18:47:49 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: slw@zxy.spb.ru X-Bugzilla-Status: In Progress X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Mar 2017 18:47:50 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D217637 --- Comment #67 from slw@zxy.spb.ru --- (In reply to Michael Tuexen from comment #66) > No, the loss of data is caused by the application calling close() *before= *=20 > incoming user data arrived. Loss of sended application data caused by close() before incoming user data arrived? Realy? TCP don't have such claim. > So the TCP stack on the server has to drop that user data. No problem. This is not application data. > Sure. This is what the application triggers. However, when user data arri= ves after > the close call, this gets ungraceful, since this user data can't be deliv= ered to > the user anymore. I am not afraid about user data, I am afraid about server data. Server data lost and this is problem. No problem about lose user data. > I don't see text in RFC 793, where it is required that you continue to pr= ocess > a connection after you know that it failed.=20 What reason to failed connection? > I think the RFC doesn't cover the case > where the application says "I don't want to receive anymore". Yes, RFC says all CLOSE is 'means "I have no more to send" but does not mea= n "I will not receive any more."' I mean "Thus, it should be acceptable to make several SEND calls, followed = by a CLOSE, and expect all the data to be sent to the destination." have precend= ece over all. "Reset Generation" allow generation RST from ESTABLISHED/FIN-WAIT-1/fIN-WAI= T-2 state only "If an incoming segment has a security level, or compartment, or precedence which does not exactly match the level" Also, "3.9. Event Processing", "SEGMENT ARRIVES" don't generate RST in ESTABLISHED/FIN-WAIT-1/FIN-WAIT-2 STATE. I mean conection not in failed state until all server data and FIN will be ACKed. Or at timeout. After this, connection may be moved to failed state. Not until. PS: May proposal resolve next issuse: 1. server response not lost any more 2. client see valid replay from server, not just 'connection droped' 3. late segments from client don't mach syn-cookei and don't re-open connec= tion 4. no new restrictions for first segment syn cookie processing 5. client side of connection clearly closed (currently generated RST w/o ACK ignored by all clients except FreeBSD. this is another bug) 6. this is compatible w/ existing applications --=20 You are receiving this mail because: You are the assignee for the bug.=