Heads up --- Thinking about UDP and tunneling

[Randall Stewart]

All:

Ok here is what I have come up with.. going along the
lines of Max's suggestion.. its pretty clean I think.

Comments would be most welcome..

The only thing possibly a bit dodgy is that

1) UDP has no per-protocol block.
2) Instead of creating one, I am using the block pointer in the inp
   as the function pointer for the tunneling.

What this means if we EVERY did add a per protocol structure for
UDP we would need to move the function pointer in there..

The nice thing it does is make it so we have no structural changes to
the code... i.e. complete compatibility... no changes to inp or
other UDP structures :-)


Here is the patch.. please send comments ;-D

diff_for_udp
Description: Binary data

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

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).

the IP header. It may not even be in the mbufs you have. (though it's unlikely). After you've processed the UDP part the IP part is gone so

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...

One would definitely have to do some work in udp_input() not a lot from

might be some problems with holding the socket lock, though.


a somewhat reasonable implementation for this hackery.

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This sounds reasonable. One would only have to replace calls to udp_append in udp_input with the by-pass function et voila. Should be clean enough. There For the record, I don't like all the UDP-tunneling madness either, but it seems that we are stuck with it ... so we should at least try to come up with

------------------------------
Randall Stewart
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