MFC r342377:

Remove NETBSD_PF. NETBSD_PF is a flag that defines whether the pfil(9)
framework is available. pfil(9) has been in FreeBSD since FreeBSD 5
and according to svn log was first committed to HEAD in 2000, therefore
it is safe to say the check is no longer needed in FreeBSD.

pfil(9) first appeared in NetBSD 1.3 (hence the name NETBSD_PF).
Therefore it is safe to say that it is supported by every NetBSD system
today. The framework also exists in illumos.

As ipfilter code is shared and exchanged between FreeBSD and NetBSD, and
at some point in the future illumos too, and as all three platforms have
pfil(9), the redundant NETBSD_PF #defines and #ifdefs are removed.

MFC r341279:

Clean up a redundant non-redefinition of IFNAMSIZ. IFNAMSIZ
is defined in net/if.h, therefore the condition is never met and
confusing to those who follow.

MFC r341650:

Remove an ugly Ultrix hack. Ultrix has been AWOL since the last ice
age, more to come.

MFC r337410:

Remove redundant and incorrect default definition of AF_INET6. AF_INET6
is defined in sys/socket.h where it's defined as 28.

A bit of trivia: On NetBSD AF_INET6 is defined as 24. On Solaris it is
defined as 26. This is probably why Darren defaulted to 26, because
ipfilter was originally written for SunOS 4 and Solaris many moons ago.

MFC r312787:

Currently the fragment info is placed at the top of the linked list
under a shared read lock. This patch attempts to upgrade the lock to
an exclusive write lock. If the exclusive write lock fails to be
obtained, the current fragment is not placed at the head of the list.

This portion of the patch was inspired by NetBSD ip_frag.c r1.4 (which
effectively removed the section of code that performed the reordering).

The patch to sys/contrib/ipfilter/netinet/ip_compat.h adds the
MUTEX_TRY_UPGRADE macro to support the patch to ip_frag.c.

The patch to contrib/ipfilter/lib/rwlock_emul.c supports this patch
by emulating the mutex in userspace when exercised by ipftest(1).

Inspired by: NetBSD ip_frag.c r1.4

MFC r304953:

Define ipfilter's SOLARIS macro in a defined and portable way.

Reviewed by: cy
Differential Revision: https://reviews.freebsd.org/D7671

MFC r304959 (by kib):

Complete r304953.

Sponsored by: The FreeBSD Foundation

MFC r304964:

Follow-up to r304953, in which I broke the build: apparently the SOLARIS
macro is defined in lots of different places in ipfilter, so replace all
of the nonportable definitions with portable ones.

Pointy hat to: dim

MFC r269585 - Honour WITH and WITHOUT_INET6_SUPPORT.

Approved by: glebius (mentor - implicit)

MFC r268532 and r268585. When world and kernel are built without INET6
support, the userland was still built with INET6 turned on.

PR: 190964
Approved by: glebius (mentor, implicit)

MFC r269585 - Honour WITH and WITHOUT_INET6_SUPPORT.

Approved by: glebius (mentor - implicit)

MFC r268532 and r268585. When world and kernel are built without INET6
support, the userland was still built with INET6 turned on.

PR: 190964
Approved by: glebius (mentor, implicit)