From owner-freebsd-net@freebsd.org Mon Mar 20 17:31:08 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 36715D14214 for ; Mon, 20 Mar 2017 17:31:08 +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 260A610DE for ; Mon, 20 Mar 2017 17:31:08 +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 v2KHV7F9036321 for ; Mon, 20 Mar 2017 17:31:08 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 17:31:08 +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: tuexen@freebsd.org 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 17:31:08 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D217637 --- Comment #66 from Michael Tuexen --- (In reply to slw from comment #65) > This is wrong behaviour. This is cause lost of server data. No, the loss of data is caused by the application calling close() *before* incoming user data arrived. So the TCP stack on the server has to drop that user data. > pwrite(); > close(); > This is graceful termination. Sure. This is what the application triggers. However, when user data arrives after the close call, this gets ungraceful, since this user data can't be deliver= ed to the user anymore. To avoid this, the application could call shutdown(..., SHUT_WR) to trigger the sending of the FIN, then process incoming data until a FIN f= rom the peer arrives and then calling close(). But the application didn't. This wou= ld be more in line of how RFC 793 describes a connection termination. Please note that the CLOSE primitive in RFC 793 maps to a shutdown(..., SHUT_WR) system call, not to the close() system call. Bad naming...=20 I don't see text in RFC 793, where it is required that you continue to proc= ess a connection after you know that it failed. I think the RFC doesn't cover t= he case where the application says "I don't want to receive anymore". --=20 You are receiving this mail because: You are the assignee for the bug.=