NetBSD Problem Report #17616

Received: (qmail 19663 invoked by uid 605); 16 Jul 2002 21:12:17 -0000
Message-Id: <20020716211216.19654.qmail@mail.netbsd.org>
Date: 16 Jul 2002 21:12:16 -0000
From: wrstuden@netbsd.org
Sender: gnats-bugs-owner@netbsd.org
Reply-To: wrstuden@netbsd.org
To: gnats-bugs@gnats.netbsd.org
Subject: accept on a tcp socket loses options
X-Send-Pr-Version: 3.95

>Number:         17616
>Category:       kern
>Synopsis:       accept on a tcp socket loses options
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 16 21:13:01 +0000 2002
>Closed-Date:    
>Last-Modified:  
>Originator:     Bill Studenmund
>Release:        NetBSD 1.6, though it has been around a while
>Organization:
NetBSD

>Environment:

System: NetBSD mail 1.5 NetBSD 1.5 (HOMEWORLD) #0: Sat Feb 10 08:13:16 EET 2001 mycroft@netbsd.hut.fi:/usr/src/sys/arch/i386/compile/HOMEWORLD i386


>Description:
	When a listening tcp socket gains a new connection (which will be
retrieved by accept(2)), the tcp options of the listening socket
are not copied over. Quoting man 2 accept, "The accept() argument
extracts the first connection request on the queue of pending
connections, creates a new socket with the same properties of s
[the accepted-on socket] and allocates a new file descriptor for
the socket." tcp options certainly are properties of the accepted-
on socket (though admittedly not socket-level ones).
	Other operating systems, such as Linux, do copy over the
tcp options. While I don't think we should do something just because
someone else did, in this case, I think copying tcp options is the
right thing to do.

>How-To-Repeat:

	Create a tcp socket & bind it to an address. Set tcp options
on it, such as TCP_NODELAY. accept() a new connection. You now have
a socket without the option(s) you set above.

>Fix:

	Not sure. But when we transition a tcp connection from
TCPS_SYN_RECEIVED to ESTABLISHED, we should copy the tcp options
of the listen-on socket. One possible way to do this is to save
the tcp options along with the ip options when we add an entry to
the syn cache.
>Release-Note:
>Audit-Trail:
>Unformatted:

NetBSD Home
NetBSD PR Database Search

(Contact us) $NetBSD: query-full-pr,v 1.39 2013/11/01 18:47:49 spz Exp $
$NetBSD: gnats_config.sh,v 1.8 2006/05/07 09:23:38 tsutsui Exp $
Copyright © 1994-2007 The NetBSD Foundation, Inc. ALL RIGHTS RESERVED.