Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

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

Ignore the return value of ADDCARRY().

Use in_cksum_skip() to calculate in4_cksum instead of doing handrolled magic
(that does not compile with !gcc). Moreover we get the benefit for all archs
that have a hand optimized in_cksum_skip().

Submitted by: yongari
Tested by: me (i386, extensivly), pf4freebsd ML (various)

Commit pf version 3.5 and link additional files to the kernel build.

Version 3.5 brings:
- Atomic commits of ruleset changes (reduce the chance of ending up in an
inconsistent state).
- A 30% reduction in the size of state table entries.
- Source-tracking (limit number of clients and states per client).
- Sticky-address (the flexibility of round-robin with the benefits of
source-hash).
- Significant improvements to interface handling.
- and many more ...

Bring diff from the security/pf port. This has code been tested as a port
for a long time and is run in production use. This is the code present in
portversion 2.03 with some additional tweaks.

The rather extensive diff accounts for:
- locking (to enable pf to work with a giant-free netstack)
- byte order difference between OpenBSD and FreeBSD for ip_len/ip_off
- conversion from pool(9) to zone(9)
- api differences etc.

Approved by: bms(mentor) (in general)

This commit was generated by cvs2svn to compensate for changes in r126258,
which included commits to RCS files with non-trunk default branches.

Vendor import of OpenBSD's packet filter (pf) as of OpenBSD 3.4

Approved by: bms(mentor), core (in general)