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
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>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:
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