Having single port for all iSCSI connections makes problematic implementing
some more advanced SCSI functionality in CTL, that require proper ports
enumeration and identification.
This change extends CTL iSCSI API, making ctld daemon to control list of
iSCSI ports in CTL. When new target is defined in config fine, ctld will
create respective port in CTL. When target is removed -- port will be
also removed after all active commands through that port properly aborted.
This change require ctld to be rebuilt to match the kernel.
As a minor side effect, this allows to have iSCSI targets without LUNs.
While that may look odd and not very useful, that is not incorrect.
needed it to be already enabled, because listening in proxy mode
requires it; however, it's conf_apply() that opens pidfiles,
so it resulted in port being enabled before pidfile was opened.
This was not so bad, but it was also disabled when pidfile couldn't
be opened due to ctld already running; this means that starting
second ctld instance screwed up the first.
Sponsored by: The FreeBSD Foundation
