Date: Wed, 9 Sep 1998 00:02:26 -0700 (PDT) From: Archie Cobbs <archie@whistle.com> To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: net@FreeBSD.ORG Subject: Re: Will the TEE function of IPFW be ever implemented/necessary ? Message-ID: <199809090702.AAA21914@bubba.whistle.com> In-Reply-To: <199809080452.GAA16954@labinfo.iet.unipi.it> from Luigi Rizzo at "Sep 8, 98 06:52:35 am"
next in thread | previous in thread | raw e-mail | index | archive | help
Luigi Rizzo writes: > > I'd prefer that someone implemented it, because a few people have > > asked for it, but on the other hand if no one is even going to implement > > yes but _how_ do people want to use it ? > Really, TEE is of very little use for everything i can think of, > because the user > * cannot exercise any form of flow control; > * is likely to get data out of order (depending on what happens > in the network) and/or retransmissions; > * has to separate data in the two directions, > > the policy that one wants to use for the above are so largely variable > that it makes little sense to put them in the kernel, and better rely > on a user-space process to do this. At which point, a BPF process would > be at least more portable to different architectures! Well, all I can say is that I don't know what people might want to use it for, but people always seem to find a way to suprise us when it comes to these things. For example, suppose some hyper-paranoid person wanted to keep a copy of every packet that was received by their machine, writing it to some kind of high-speed WORM device or something. Then they could just say ipfw add 100 tee 1234 ip from any to any in Sure it sounds crazy to you and me, but who knows?? In this case it would be easier to do this with ipfw than with BPF, because you don't have to open a BPF device on every interface (or even know what interfaces exist), etc. I'm just making this up and it's not a great example, but my point is that it's not for you or me to decide that there are no applications for something just because *we* can't think of any... On the other hand, I'm not claiming that ipfw tee will ever prove useful either.. but as long as it's not hurting anything, and maybe someday it might prove useful, why not just leave it alone. > > it then it might as well go away (if you need the bit for something > > else, that is). > > that's not a major issue since Poul solved the problem by widening > the field for ipfw commands in 3.0, and i have room for that in > -stable. That's good.. -Archie ___________________________________________________________________________ Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199809090702.AAA21914>