sys: Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

pf: make contents of struct pfsync_state configurable

Make struct pfsync_state contents configurable by sending out new
versions of the structure in separate subheader actions. Both old and
new version of struct pfsync_state can be understood, so replication of
states from a system running an older kernel is possible. The version
being sent out is configured using ifconfig pfsync0 … version XXXX. The
version is an user-friendly string - 1301 stands for FreeBSD 13.1 (I
have checked synchronization against a host running 13.1), 1400 stands
for 14.0.

A host running an older kernel will just ignore the messages and count
them as "packets discarded for bad action".

Reviewed by: kp
Sponsored by: InnoGames GmbH
Differential Revision: https://reviews.freebsd.org/D39392

pfsync: Remove deletion of states using the full pfsync_state struct

State deletions are sent over pfsync using struct pfsync_del_c.

Remove the code for receiving state deletions using struct pfsync_state
as such deletions are never sent. Rename functions and constants so that
only the "compressed" versions remain.

Reviewed by: kp
Sponsored by: InnoGames GmbH
Differential Revision: https://reviews.freebsd.org/D40004

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

pfsync: prepare code to accommodate AF_INET6 family

Work is ongoing to add support for pfsync over IPv6. This required some
changes to allow for differentiating between the two families in a more
generic way.

This patch converts the relevant ioctls to using nvlists, making future
extensions (such as supporting IPv6 addresses) easier.

Sponsored by: InnoGames GmbH
Differential Revision: https://reviews.freebsd.org/D36277

pf: make if_pfsync.h self-contained

Reviewed by: imp
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D33504

pfsync: Expose PFSYNCF_OK flag to userspace

Add 'syncok' field to ifconfig's pfsync interface output. This allows
userspace to figure out when pfsync has completed the initial bulk
import.

Reviewed by: donner
MFC after: 2 weeks
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D29948

Fix some common typos in comments

- occured -> occurred
- normaly -> normally
- controling -> controlling
- fileds -> fields
- insterted -> inserted
- outputing -> outputting

MFC after: 1 week

net: clean up empty lines in .c and .h files

sys: 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.

Remove more constants related to static sysctl nodes. The MAXID constants
were primarily used to size the sysctl name list macros that were removed
in r254295. A few other constants either did not have an associated
sysctl node, or the associated node used OID_AUTO instead.

PR: ports/184525 (exp-run)

Remove most of the remaining sysctl name list macros. They were only
ever intended for use in sysctl(8) and it has not used them for many
years.

Reviewed by: bde
Tested by: exp-run by bdrewery

Finish the r244185. This fixes ever growing counter of pfsync bad
length packets, which was actually harmless.

Note that peers with different version of head/ may grow this
counter, but it is harmless - all pfsync data is processed.

Reported & tested by: Anton Yuzhaninov <citrin citrin.ru>
Sponsored by: Nginx, Inc

- Add dashes before copyright notices.
- Add $FreeBSD$.
- Remove unused define.

o Create directory sys/netpfil, where all packet filters should
reside, and move there ipfw(4) and pf(4).

o Move most modified parts of pf out of contrib.

Actual movements:

sys/contrib/pf/net/*.c -> sys/netpfil/pf/
sys/contrib/pf/net/*.h -> sys/net/
contrib/pf/pfctl/*.c -> sbin/pfctl
contrib/pf/pfctl/*.h -> sbin/pfctl
contrib/pf/pfctl/pfctl.8 -> sbin/pfctl
contrib/pf/pfctl/*.4 -> share/man/man4
contrib/pf/pfctl/*.5 -> share/man/man5

sys/netinet/ipfw -> sys/netpfil/ipfw

The arguable movement is pf/net/*.h -> sys/net. There are
future plans to refactor pf includes, so I decided not to
break things twice.

Not modified bits of pf left in contrib: authpf, ftp-proxy,
tftp-proxy, pflogd.

The ipfw(4) movement is planned to be merged to stable/9,
to make head and stable match.

Discussed with: bz, luigi