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

Fix ndp(8) -f flag parsing

PR: bin/136661
Reminded by: Vinicius Zavam
MFC after: 2 weeks

Include descriptions of the flags and fields printed when dumping the
IPv6 prefix list.

Reviewed by: hrs
MFC after: 1 week

Add no_prefer_iface option.
It stops treating the address on the interface as special by source
address selection rule even when the interface is outgoing interface.
This is desired in some situation.

Requested by: hrs
Reviewed by: IHANet folks including hrs
MFC after: 1 week

Minor wording improvments to some manual pages

Approved by: bcr (mentor)
Obtained from: DragonflyBSD (a5294ca835317c68c919ab43936da4f05ab6e926)
MFC after: 3 days

Remove "prefer_source" address selection option. FreeBSD has had an
implementation of RFC 3484 for this purpose for a long time and "prefer_source"
was never implemented actually. ND6_IFF_PREFER_SOURCE macro is left intact.

Improve flexibility of receiving Router Advertisement and
automatic link-local address configuration:

- Convert a sysctl net.inet6.ip6.accept_rtadv to one for the
default value of a per-IF flag ND6_IFF_ACCEPT_RTADV, not a
global knob. The default value of the sysctl is 0.

- Add a new per-IF flag ND6_IFF_AUTO_LINKLOCAL and convert a
sysctl net.inet6.ip6.auto_linklocal to one for its default
value. The default value of the sysctl is 1.

- Make ND6_IFF_IFDISABLED more robust. It can be used to disable
IPv6 functionality of an interface now.

- Receiving RA is allowed if ip6_forwarding==0 *and*
ND6_IFF_ACCEPT_RTADV is set on that interface. The former
condition will be revisited later to support a "host + router" box
like IPv6 CPE router. The current behavior is compatible with
the older releases of FreeBSD.

- The ifconfig(8) now supports these ND6 flags as well as "nud",
"prefer_source", and "disabled" in ndp(8). The ndp(8) now
supports "auto_linklocal".

Discussed with: bz and jinmei
Reviewed by: bz
MFC after: 3 days

-mdoc sweep.

supported an ndp command suboption to disable IPv6 in the given interface

Obtained from: KAME
Reviewd by: ume, gnn
MFC after: 2 week

added an ioctl option in kernel so that ndp/rtadvd can change some NDP-related kernel variables based on their configurations (RFC2461 p.43 6.2.1 mandates this for IPv6 routers)

Obtained from: KAME
Reviewd by: ume, gnn
MFC after: 2 weeks

Fixed the misplaced $FreeBSD$.

Fixed xref.

Added the EXIT STATUS section where appropriate.

Markup and grammar nits.

Trim whitespace at EOL.

- make command line argument parsing POSIX compliant. comment from
deraadt NOTE: -I needs to take an arg (there's no way we can take no
arg/an arg with a single option)
- sscanf overrun
- no variable name on prototype.
- u_int32_t may not be u_long.
- skipped non-host route when printing neighbor cache entries.
- valid and preferred lifetimes are unsigned.
- wording.

Obtained from: KAME

introduced a flag bit "ND6_IFF_ACCEPT_RTADV" in the nd_ifinfo structure to
control whether to accept RAs per-interface basis.
the new stuff ensures the backward compatibility;
- the kernel does not accept RAs on any interfaces by default.
- since the default value of the flag bit is on, the kernel accepts RAs
on all interfaces when net.inet6.ip6.accept_rtadv is 1.

Obtained from: KAME
MFC after: 1 week

Fix typos, mostly s/ an / a / where appropriate and a few s/an/and/
Add FreeBSD Id tag where missing.

The .Nm utility

mdoc(7) police:

Avoid using parenthesis enclosure macros (.Pq and .Po/.Pc) with plain text.
Not only this slows down the mdoc(7) processing significantly, but it also
has an undesired (in this case) effect of disabling hyphenation within the
entire enclosed block.

Sync with recent KAME.
This work was based on kame-20010528-freebsd43-snap.tgz and some
critical problem after the snap was out were fixed.
There are many many changes since last KAME merge.

TODO:
- The definitions of SADB_* in sys/net/pfkeyv2.h are still different
from RFC2407/IANA assignment because of binary compatibility
issue. It should be fixed under 5-CURRENT.
- ip6po_m member of struct ip6_pktopts is no longer used. But, it
is still there because of binary compatibility issue. It should
be removed under 5-CURRENT.

Reviewed by: itojun
Obtained from: KAME
MFC after: 3 weeks

mdoc(7) police: split punctuation characters + misc fixes.

mdoc(7) police: use the new features of the Nm macro.

sync with latest kame tree

Slight grammar and white-space modification.

libipsec and IPsec related apps. (and some KAME related man pages)

Reviewed by: freebsd-arch, cvs-committers
Obtained from: KAME project