ctld(8), multiple 'portal-group' on same socket (individual 'discovery-auth-group' restrictions)

[Edward Tomasz Napierała]

On 1020T1035, Harald Schmalzbauer wrote:
>  Hello,
> 
> I'm trying to move from istgt(1) to ctld(8), but it seems my setup isn't
> possible with ctld.
> Besides missing support for virtual-DVDs ('UnitType DVD' in istgt) and
> real ODD-devices ('UnitType pass' in istgt),

Yup, we don't implement virtual DVDs and passthrough.  Especially the
latter would be a nice feature to have.

> I guess it's impossible to
> define multiple "portal-group"s, listening on the same socket, but with
> different "discovery-auth-group".
> The idea is, to present initiators only targets at discovery, which they
> are allowed to connect to.
> Am I missing something which could provide such selective discovery with
> ctld(8)?

I thought about it, but I don't like the way istgt does it.  By allowing
multiple portal groups to bind to a single address (portal), we would
introduce ambiguity as for which portal-group and associated
discovery-auth-group is being used.  On the other hand, a simplistic
approach of only showing targets with auth-group being the same
as discovery-auth-group for the portal probably wouldn't be very useful
in real-world cases.