Date: Thu, 20 Nov 2008 12:37:47 -0500 From: Randall Stewart <rrs@lakerest.net> To: Max Laier <max@love2party.net> Cc: freebsd-net@freebsd.org, Julian Elischer <julian@elischer.org> Subject: Re: Thinking about UDP and tunneling Message-ID: <C38C5016-D263-42A9-9D90-2363B2EA64DE@lakerest.net> In-Reply-To: <200811201450.30016.max@love2party.net> References: <D72E9703-C8E7-4A21-A71E-A4B4C2D7E8F4@lakerest.net> <49249443.8050707@elischer.org> <76CF7D15-251F-4E43-86BE-AD96F48AF123@lakerest.net> <200811201450.30016.max@love2party.net>
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On Nov 20, 2008, at 8:50 AM, Max Laier wrote: > On Thursday 20 November 2008 14:00:11 Randall Stewart wrote: >> On Nov 19, 2008, at 5:33 PM, Julian Elischer wrote: >>>> Its not new, its the same ip header.. >>>> Its just you go into the mbuf chain and take out >>>> the udp header... >>> >>> well you can't do that at the socket buffer becasue you've discarded >>> the IP header. It may not even be in the mbufs you have. (though =20 >>> it's >>> unlikely). After you've processed the UDP part the IP part is gone =20= >>> so >>> you'd need to intercept the packet way earlier and then do your >>> own UDP processing, (or maybe attach the IP header onto it with a >>> tag). >> >> One would definitely have to do some work in udp_input() not a lot =20= >> from >> what I can tell... but it would take some work. >> >> Maybe good course is to use the socket(9) stuff, but add an option >> that can set a "by-pass function" if the socket is udp... right >> after you establish the INP the packet goes to, if the function is >> set, you engage the bypass... > > This sounds reasonable. One would only have to replace calls to =20 > udp_append in > udp_input with the by-pass function et voila. Should be clean =20 > enough. There > might be some problems with holding the socket lock, though. > > For the record, I don't like all the UDP-tunneling madness either, =20 > but it > seems that we are stuck with it ... so we should at least try to =20 > come up with > a somewhat reasonable implementation for this hackery. Max: This was along the lines of what I was thinking exactly.. one side note. I am told by my colleague in SCTP crime (Michael T=FCxen) that = Apple has this functional by-pass interface. He has already got the UDP =20 tunneling code working in the MAC version of our stack :-) I will start working on this when I get back from the IETF. I need to =20= finish up the NAT support stuff (almost done) and then I will start looking at the locking issues that this may bring... R > > > --=20 > /"\ Best regards, | mlaier@freebsd.org > \ / Max Laier | ICQ #67774661 > X http://pf4freebsd.love2party.net/ | mlaier@EFnet > / \ ASCII Ribbon Campaign | Against HTML Mail and News > ------------------------------ Randall Stewart 803-317-4952 (cell) 803-345-0391(direct)
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