Re: [9fans] NAT implementation

[Nathaniel W Filardo <nwf@cs.jhu.edu>]

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On Wed, Apr 15, 2009 at 02:03:35PM +0200, Patrick Kristiansen wrote:
> I'm thinking of writing a NAT implementation for plan 9.

I would suggest instead that it might be easier to write an adaptor program
for non-Plan 9 hosts which made their network stacks talk to a /net.  That
is, you'd want a program which spoke TAP/TUN out one end to the host kernel
and out the other dialed and imported /net from the Plan 9 gateway.  AFAIK
TAP/TUN-like things exist on most OSes, and there's good example code in
OpenVPN (for example).

The program would have to know enough about the on-the-wire representation
of TCP/IP and UDP/IP to do connection tracking etc. (much like NAT, I
suppose) but the advantage is that it wouldn't impact the Plan 9 kernel.

--nwf;

P.S. This idea shamelessly stolen from vsrinivas, but he's mailing-list shy.

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