Date: Tue, 31 Aug 2010 15:01:34 +0200 From: =?iso-8859-1?Q?Michael_T=FCxen?= <Michael.Tuexen@lurchi.franken.de> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-net@freebsd.org, Andre Oppermann <andre@freebsd.org> Subject: Re: Removal of deprecated implied connect for TCP Message-ID: <7B42D7FB-B782-4EE9-8813-BF7D3ED3274B@lurchi.franken.de> In-Reply-To: <alpine.BSF.2.00.1008311102220.22661@fledge.watson.org> References: <4C7A7B25.9040300@freebsd.org> <alpine.BSF.2.00.1008311102220.22661@fledge.watson.org>
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On Aug 31, 2010, at 12:04 PM, Robert Watson wrote: > > On Sun, 29 Aug 2010, Andre Oppermann wrote: > >> When T/TCP RFC1644 support was introduced in r6283 by wollman 15 years ago the semantics of sendto(2) with regard to TCP sockets were changed. >> >> It became possible directly do a sendto(2) call with the target address in the *to argument instead of doing a connect(2) first and subsequent write(2) or send(2) calls as the standard TCP API specifies. Optionally MSG_EOR could be specified to close the connection again right again after the data has been sent out. >> >> This is totally non-portable and no other OS (Linux, NetBSD, OpenBSD, Solaris, HP-UX) ever supported this functionality for TCP sockets. FreeBSD was the only OS to ever ship this. >> >> T/TCP was ill-defined and had major security issues and never gained any support. It has been defunct in FreeBSD and most code has been removed about 6 years ago. The sendto(2) extended functionality is one of the last parts that persisted and remained around living a zombie life. >> >> I want to remove it now because it is totally non-portable, has no known users and complicates the TCP send path. The patch is attached. >> >> If you have any objections speak up now. > > I'm not entirely comfortable with this change, and would like a chance to cogitate on it a bit more. While I'm not aware of any applications depending on the semantic for TCP, I know that we do use it for UNIX domain sockets. Since it's a documented API, if we are going to remove it, then we need to go through a deprecation process, not least by marking it as a deprecated API in 8.x before having it vanish in 9.0. sendto() is also used for SCTP SOCK_STREAMS and SOCK_SEQPACKET sockets... Best regards Michael > > (I won't be sorry to see the complexity go, but I'm not sure I have all the implications in mind as yet...) > > Robert > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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