Re: [9fans] 9vx dns funny

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

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On Tue, Jul 08, 2008 at 01:17:53PM -0400, Russ Cox wrote:
> > i guess this gets to a more philosophical question
> > on how 9vx networking relates to the host.
> > 
> > personally, i feel it would be more useful to be
> > able to use plan 9's native network stack.  but
> > i'm biased.  i want to send aoe/cec/il packets.
> 
> I'm happy to accomodate these kinds of things,
> but I don't want to make it required.  Running the
> native TCP/IP stack requires being able to send and
> receive raw ethernet frames on an otherwise unused
> ethernet device, something most machines don't have
> and also something that usually requires being root.
> This would hamper portability quite a bit.
> 
> It would be trivial to write a devether, like devip,
> that handles raw ethernet frames.  You'd still have to
> be root on most systems, but if you stay away from
> sending TCP and UDP packets, you can coexist
> with the host OS on a single ethernet device.  
> That would be make sending aoe and cec very easy,
> and if you did a bit more work and the host OS turned
> a blind eye, you might even get away with IL.
> I'd rather see that than drag in the entire network
> stack from the Plan 9 kernel.

Just a reminder, nothing novel: if you don't mind being root on the host
briefly (to run ifconfig, brctl, and tunctl commands), you can create a new
TAP interface (and use the file descriptor in 9vx to back a devether) and
use Linux's bridging to get ethernet frames to/from the real network
interface.  This eliminates any "stay away from TCP/UDP" requirement and
also lets you use just a single ethernet device.  If the Linux host needs to
be on the network, it can get its own IP or can be made to masquerade
(yick).

IIRC THNX does something similar; is there a reason this is unsatisfactory
for the uses at hand?

--nwf;

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