Re: [Nbd] [RFC] NBD protocol improvement

[Laurent Vivier <Laurent.Vivier@...154...>]

Le jeudi 11 septembre 2008 à 12:19 -0400, Paul Clements a écrit :
> Laurent Vivier wrote:
> > I use the NBD protocol to connect a virtual machine to a disk image.
> > 
> > I'd like to allow the client to specify the file to use.
> > 
> > Here is what I propose, all your comments are welcome:
> > 
> > * NBD server side:
> > 
> >   - put all the disk images in a directory, for instance:
> > 
> >     # ls /ISO
> >     ubuntu-6.06-desktop-amd64.iso
> >     ubuntu-7.10-desktop-amd64.iso
> >     ubuntu-8.04-desktop-i386.iso
> > 
> >   - run the NBD server with a new parameter to specify the directory
> >     instead of the filename
> > 
> >     # nbd-server 1024 --read-only --directory /ISO
> > 
> > * NBD client side
> > 
> >   nbd-client isoserver 1024 /dev/nbd0 ubuntu-8.04-desktop-i386.iso
> > 
> > * protocol changes:
> > 
> > - when used with "--directory", nbd-server sends a disk size of 0 in the
> > negotiate operation.
> > - when nbd-client receive a disk size of zero, it sends a filename
> > (first bytes is the size of the filename, following bytes are the
> > filename).
> > - nbd-server receives the filename, opens the file (to avoid security
> > issues, we use "basename(filename)"), and re-sends a negotiate packet
> > with the good size.
> > - next is as ususal.
> 
> Hi Laurent,
> 
> so do you have a patch? Is this a patch to standard nbd-client/server? 

I have a patch for qemu-nbd.

But if you agree with the concept, I think I can do a patch for
nbd-client/server (if I want this becomes an official NBD feature I
think I have to do it... ;-) )

> Are their any kernel components (I assume not)?

I didn't dig in, but I don't think so.

> Thanks,
> Paul

Regards,
Laurent
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