From owner-freebsd-net@freebsd.org Sun Mar 19 17:10:55 2017 Return-Path: <owner-freebsd-net@freebsd.org> 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 7BDDCD0F50D for <freebsd-net@mailman.ysv.freebsd.org>; Sun, 19 Mar 2017 17:10:55 +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 60C8BFB8 for <freebsd-net@FreeBSD.org>; Sun, 19 Mar 2017 17:10:55 +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 v2JHAteZ099150 for <freebsd-net@FreeBSD.org>; Sun, 19 Mar 2017 17:10:55 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: Sun, 19 Mar 2017 17:10:55 +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: <bug-217637-2472-DMZ14cyJr9@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-217637-2472@https.bugs.freebsd.org/bugzilla/> References: <bug-217637-2472@https.bugs.freebsd.org/bugzilla/> 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 <freebsd-net.freebsd.org> List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net/> List-Post: <mailto:freebsd-net@freebsd.org> List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help> List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=subscribe> X-List-Received-Date: Sun, 19 Mar 2017 17:10:55 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D217637 --- Comment #33 from Michael Tuexen <tuexen@freebsd.org> --- (In reply to slw from comment #32) The server does socket() listen() accept() read() write() close() which means it reads the first part of the request, sends the response (en error message) and closes the socket. Then the state is FIN-WAIT-1. Then it receives the second part of the request. Since the socket is closed, it responds with a = RST segment and moves the connection to CLOSED. This covers the first TCP connection of the two. After that that the client retransmits the complete request, which results = in establishing the second TCP connection (via the syncookie processing). The server sends a response (the same error message) and closes the socket. So = it is again in FIN-WAIT-1. The FIN gets acked by the client. So the server goes into FIN-WAIT-2. Then the client sends its fin. This is processed by the se= rver and acked. Now the server is in TIME-WAIT. However, the ACK is not received= by the client and the client retransmits the FIN-ACK. So I don't see any end point moving into CLOSE-WAIT state... --=20 You are receiving this mail because: You are the assignee for the bug.=