Date: Thu, 21 Oct 2004 23:41:47 +0400 (MSD) From: Igor Sysoev <is@rambler-co.ru> To: Sean Chittenden <sean@chittenden.org> Cc: freebsd-arch@freebsd.org Subject: Re: Removing T/TCP and replacing it with something simpler Message-ID: <20041021233447.L91215@is.park.rambler.ru> In-Reply-To: <E0C34A72-2396-11D9-9171-000A95C705DC@chittenden.org> References: <4177C8AD.6060706@freebsd.org> <71C3A1EA-238F-11D9-9171-000A95C705DC@chittenden.org> <E0C34A72-2396-11D9-9171-000A95C705DC@chittenden.org>
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On Thu, 21 Oct 2004, Sean Chittenden wrote: > >> In 2001, there was a push to make Linux's TCP_CORK option behave the > >> same as FreeBSD's TCP_NOPUSH. Is maintaining that compatibility still > >> a goal, or are we going to kick this change off to the Linux folk to > >> have them play catchup (to what sounds like a more secure option than > >> Linux's TCP_CORK)? > >> > >> http://seclists.org/linux-kernel/2001/Feb/0993.html > > > > I'm not sure if I can follow you here. TCP_CORK deals with the > > different > > behaviour of connections with Nagle vs. TCP_NODELAY. TCP_CORK allows > > to > > avoid the delays of Nagle by corking (sort of blocking) the sending of > > packets until you are done with write()ing to the socket. Then the > > connection is uncorked and all data will be sent in one go even if it > > doesn't fill an entire packet. Sort of an fsync() for sockets. There > > are no security implications with TCP_CORK as far as I am aware. > > Isn't that what NOPUSH does? Or is it that CORK uses a fully > established TCP connection, but blocks sending data until the > connection has been uncorked/flushed? I thought that TCP_CORK had the > same security implications that NOPUSH does (ie, the lack of a hand > shake). I think that TCP_CORK was implemented only for Linux's sendfile() to postpone the sending of the HTTP header: http://freebsd.rambler.ru/linux/kernel_1999/msg13796.html http://freebsd.rambler.ru/linux/kernel_2001/msg61910.html Igor Sysoev http://sysoev.ru/en/
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