[Nbd] Easier use, authentication

[Christian Jaeger <chrjae@...17...>]

Hi

I'm often trying to loop-mount (actually with dmcrypt) remote
(encrypted) filesystem image files. I often do this spontaneously, and
I often already have a mount of the remote filesystem over sshfs, so I
can access these image files over the sshfs mount and my "mounte" tool
automatically takes care of the dmcrypt, thus it's a 1 step process
for me to mount such image files over sshfs. But sshfs is slow
(needless additional encryption) and sometimes not working reliably.
NBD works reliably, but is a pain to setup: I need to configure and
start a server process, start a client process with correct
configuration, then choose the right nbd block file to mount. I'd like
to look into improving that. Also, while at it, I'd hope to improve
the security by offering some kind of challenge-response
authentication. (I've written about the same thing in more length
here: http://lists.debian.org/debian-user/2011/09/msg01453.html)

If I succeed implementing that, NBD should be perfect to me, except
that it would be nice if the client could try to reconnect if the
connection fails. Ah, and it would be nice to somehow ensure that an
image file is only served at most once for safety :). But I guess NBD
is still the right way to look into, since the alternative ENBD isn't
included in the mainstream kernel?

What do you think?

I'm currently using version 2.9.16 from Debian stable.

Christian.