pflog: pass the action to pflog directly

If a packet is malformed, it is dropped by pf(4). The rule referenced
in pflog(4) is the default rule. As the default rule is a pass
rule, tcpdump printed "pass" although the packet was actually
dropped. Use the actual action, rather than the rule's action, or an
attempt at guessing the correct action.

Inspired by OpenBSD's 'pflog(4) logs packet dropped by default rule with block.' commit.

Sponsored by: Rubicon Communications, LLC ("Netgate")

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

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

pf: Fix duplicate storage of direction

The variable storing the direction of a processed packet is passed
around to many functions. Most of those functions already have a pointer
to struct pf_pdesc which also contains the direction. By using the one
in struct pf_pdesc we can reduce the amount of arguments passed around.

Reviewed by: kp
Sponsored by: InnGames GmbH
Differential Revision: https://reviews.freebsd.org/D41008

pflog: align header to 4 bytes, not 8

6d4baa0d01 incorrectly rounded the lenght of the pflog header up to 8
bytes, rather than 4.

PR: 261566
Reported by: Guy Harris <gharris@sonic.net>
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC ("Netgate")

pf: make if_pflog.h self-contained

Reviewed by: imp
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D33503

if_pflog: fix packet length

There were two issues with the new pflog packet length.
The first is that the length is expected to be a multiple of
sizeof(long), but we'd assumed it had to be a multiple of
sizeof(uint32_t).

The second is that there's some broken software out there (such as
Wireshark) that makes incorrect assumptions about the amount of padding.
That is, Wireshark assumes there's always three bytes of padding, rather
than however much is needed to get to a multiple of sizeof(long).

Fix this by adding extra padding, and a fake field to maintain
Wireshark's assumption.

Reported by: Ozkan KIRIK <ozkan.kirik@gmail.com>
Tested by: Ozkan KIRIK <ozkan.kirik@gmail.com>
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D33236

pf: Introduce ridentifier

Allow users to set a number on rules which will be exposed as part of
the pflog header.
The intent behind this is to allow users to correlate rules across
updates (remember that pf rules continue to exist and match existing
states, even if they're removed from the active ruleset) and pflog.

Obtained from: pfSense
MFC after: 3 weeks
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D32750

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.

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