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

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

ip6_randomflowlabel: Avoid blocking if random(4) is not available

If kern.random.initial_seeding.bypass_before_seeding is disabled, random(4)
and arc4random(9) will block indefinitely until enough entropy is available
to initially seed Fortuna.

It seems that zero flowids are perfectly valid, so avoid blocking on random
until initial seeding takes place.

Discussed with: bz (earlier revision)
Reviewed by: thj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20011

Fix some typos.

Obtained from: OpenBSD (CVS v1.5)

netinet6/ip6_id.c: niels kindly dropped clause 3/4 from the license.

This bring back r327293 from OpenBSD, with the important difference that
we are now getting it from their ip6_id.c file.

Obtained from: OpenBSD (CVS v1.3)

Start syncing changes from OpenBSD's ip6_id.c instead of ip_id.c.

correct non-repetitive ID code, based on comments from niels provos.
- seed2 is necessary, but use it as "seed2 + x" not "seed2 ^ x".
- skipping number is not needed, so disable it for 16bit generator (makes
the repetition period to 30000)

Obtained from: OpenBSD (CVS rev. 1.2)
MFC after: 1 week

Revert r327293
netinet6/ip6_id.c: niels kindly dropped clause 3/4 from the license.

I was looking at the wrong file. There is an important merge that must be
done before I can bring this change.

netinet6/ip6_id.c: niels kindly dropped clause 3/4 from the license.

This file is supposed to be based on the OpenBSD CVS v1.6 but checking
the OpenBSD repository the license had already dropped the 2&3 clasues by
then. Catch up with the licensing.

Obtained from: OpenBSD (CVS 1.2)

spdx: initial adoption of licensing ID tags.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Initially, only tag files that use BSD 4-Clause "Original" license.

RelNotes: yes
Differential Revision: https://reviews.freebsd.org/D13133

sys/net*: minor spelling fixes.

No functional change.

Provide includes that are needed in these files, and before were read
in implicitly via if.h -> if_var.h pollution.

Sponsored by: Netflix
Sponsored by: Nginx, Inc.

- Use time_uptime instead of time_second in data structures for
PF_INET6 in kernel. This fixes various malfunction when the wall time
clock is changed. Bump __FreeBSD_version to 1000041.

- Use clock_gettime(CLOCK_MONOTONIC_FAST) in userland utilities.

MFC after: 1 month

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Clean up VCS Ids.

ANSIfy[1] plus some style cleanup nearby.

Discussed with: gnn, rwatson
Submitted by: Karl Sj?dahl - dunceor <dunceor gmail com> [1]
Approved by: re (rwatson)

/* -> /*- for license, minor formatting changes, separate for KAME

Get rid of the RANDOM_IP_ID option and make it a sysctl. NetBSD
have already done this, so I have styled the patch on their work:

1) introduce a ip_newid() static inline function that checks
the sysctl and then decides if it should return a sequential
or random IP ID.

2) named the sysctl net.inet.ip.random_id

3) IPv6 flow IDs and fragment IDs are now always random.
Flow IDs and frag IDs are significantly less common in the
IPv6 world (ie. rarely generated per-packet), so there should
be smaller performance concerns.

The sysctl defaults to 0 (sequential IP IDs).

Reviewed by: andre, silby, mlaier, ume
Based on: NetBSD
MFC after: 2 months

add randomtab for ip6_randomflowlabel().

Obtained from: KAME

randomize IPv6 flowlabel when RANDOM_IP_ID is defined.

Obtained from: KAME

include opt_random_ip_id.h

Don't compiled ip6_randomid() in if RANDOM_IP_ID is not defined.

randomize IPv6 fragment ID.

Obtained from: KAME