MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.

MFC r310633: Add MAX_LUNS overflow safety checks.

While this MAX_LUNS limitation is too synthetic and should be removed,
it is better to enforce it while it is here.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add an additional, libucl-based configuration file parser to ctld.

Default ctld behavior remains unchanged - libucl parser can be selected
explicitly by adding -u switch to ctld command line.

Reviewed by: trasz
Approved by: trasz (mentor)
MFC after: 1 month
Relnotes: yes
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D4534

Introduce portal group options in ctl.conf.

While CTL has concept of port options, used at least for iSCSI ports now,
before this change it was impossible to set them manually. There still
no user-configurable port options now, but I am planning to change that.

Add to CTL initial support for CDROMs and removable devices.

Relnotes: yes

Add ctl-lun config option for consistency in HA setups.

Add two new portal group options "tag" and "foreign".

They are going to be useful in clustered setups.

Eliminate unused headers.

Move the "offload" clause from the target section to portal-group
section; it makes more sense there.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add missing error check.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Teach ctld(8) to control non-iSCSI CTL ports.

This change introduces new target option "port", that assigns current target
to specified CTL port. On config application ctld(8) will apply LUN mapping
according to target configuration to specified port and bring the port up.
On shutdown cltd(8) will remove the mapping and put the port down.

This change allows to configure both iSCSI and FibreChannel targets in the
same configuration file in alike way.

Kernel side support was added earlier at r278037.

MFC after: 2 weeks
Relnotes: yes
Sponsored by: iXsystems, Inc.

Make it possible to set (via ctl.conf(5)) and query (via ctladm islist -v)
target iSCSI offload. Add mechanism to query maximum receive data segment
size supported by chosen hardware offload module, and use it in ctld(8)
to determine the value to advertise to the other side.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add support for multiple portal groups per target.

This change allows multiple "portal-group" options to be specified per
target. Each of them may include new optional auth-group name parameter
to override per-target auth parameters for specific portal group.

Kernel side support was added earlier at r278161.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

CTL LUN mapping rewrite.

Replace iSCSI-specific LUN mapping mechanism with new one, working for any
ports. By default all ports are created without LUN mapping, exposing all
CTL LUNs as before. But, if needed, LUN mapping can be manually set on
per-port basis via ctladm. For its iSCSI ports ctld does it via ioctl(2).
The next step will be to teach ctld to work with FibreChannel ports also.

Respecting additional flexibility of the new mechanism, ctl.conf now allows
alternative syntax for LUN definition. LUNs can now be defined in global
context, and then referenced from targets by unique name, as needed. It
allows same LUN to be exposed several times via multiple targets.

While there, increase limit for LUNs per target in ctld from 256 to 1024.
Some initiators do not support LUNs above 255, but that is not our problem.

Discussed with: trasz
MFC after: 2 weeks
Relnotes: yes
Sponsored by: iXsystems, Inc.

Add support for sending redirections to iSCSI target.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Keep the token list sorted.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Make it possible to optionally use semicolon to separate statements.
This makes it possible to format stuff like this:

target xxx {
lun 0 { path /foo/bar; size 4G; }
}

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Simplify code; no functional changes.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add discovery-filter. This makes it possible to restrict which targets
are returned during discovery based on initiator portal, name, and CHAP
credentials.

Reviewed by: mav@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix build after previous commit. While here, improve error messages.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Remove the distinction between strings and numbers from ctld(8) yacc parser.
This fixes problems with passing strings that look like numbers to clauses
that expect strings; previously it caused syntax errors and had to be worked
by user, using quotes. The workaround introduced in r267833 is no longer
neccessary.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Add basic iSNS client to the iSCSI target.

This makes ctld(8) register its iSCSI targets and portals on configured
iSNS servers to allow initiators find them without active discovery.

Fetching of allowed initiators from iSNS is not implemented now, so target
ACLs still should be configured manually.

Reviewed by: trasz@
MFC after: 1 month
Sponsored by: iXsystems, Inc.

Whitespace fixes.

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Fix issues in config parser relating to lun serial numbers.

Without this fix some serial numbers needed to be quoted
to avoid the config parser bailing out.

Submitted by: delphij
Sponsored by: iXsystems

Rework the way we enable CTL iSCSI port. Previously conf_apply()
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

Show proper configuration file line numbers in error messages.

Sponsored by: The FreeBSD Foundation

Use new auth-type "deny" instead of using "chap" with no chap entries;
it's cleaner this way, and gives better feedback to the user.

Sponsored by: The FreeBSD Foundation

Add a new auth-group "default", defaulting to deny, and make it possible
to redefine it. From now on, assigning auth-group to a target is no longer
mandatory.

Sponsored by: The FreeBSD Foundation

Make it possible to redefine portal-group "default".

Sponsored by: The FreeBSD Foundation

Add auth-type.

Sponsored by: The FreeBSD Foundation

Rename a variable, no functional changes.

Sponsored by: The FreeBSD Foundation

Yacc cleanup; no functional changes.

Sponsored by: The FreeBSD Foundation

Implement initiator-name and initiator-portal restrictions.

Sponsored by: The FreeBSD Foundation

Fix typos.

MFC after: 3 days
Sponsored by: The FreeBSD Foundation

Bring in the new iSCSI target and initiator.

Reviewed by: ken (parts)
Approved by: re (delphij)
Sponsored by: FreeBSD Foundation