MFC r350027, r350028: Let traceroute6 not ignore some ICMPv6 packets

MFC rr350027:
Let packet_op() explicitly return the type and code instead of doing
this implicitly by encoding it in a number space.
No functional change intended.
This is done as a preparation to add support for ICMPv6 mesages
indicating a parameter problem related to the next header.

MFC r350028:
Add support for ICMPv6 messages indicating a parameter problem related
to an unrecognized next header.

MFC r333176:

Fix in the documentation that the default hop limit is not 30, but
the value of the sysctl variable net.inet6.ip6.hlim.
This is true since
https://svnweb.freebsd.org/base?view=revision&revision=122574

The default of 30 (which was correct up to r122574) was incorrectly
documented in
https://svnweb.freebsd.org/base?view=revision&revision=130268

Thanks to Timo Voelker for makeing me aware of the inconsistency
between to code and the documentation.

Approved by: re@ (marius)

MFC r328488:

When using SCTP for sending probe packets, use INIT chunks for payloads
larger than or equal to 32 bytes. For smaller probe packets, keep using
SHUTDOWN-ACK chunks, possibly bundled with a PAD chunk.
Packets with INIT chunks more likely pass through firewalls. Therefore,
use them when possible.

MFC r324120:

Add SCTP and TCP as protocols for sending probe packets.

MFC r324119:

* Update function definitions.
* Ensure that the datalen always describes the length after the IPv6
header consistently, not matter which protocol us used for probes..
* Document that the default length is 20, not 12.
* Don't send inormation in probe packets which is not needed or
even checked when the responses are processed.
* Address CID 978587.

This is mainly a cleanup preparing the addition of SCTP and TCP
as possible probe packet protocols.

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

- Add AS lookup functionality to traceroute6(8) as well.
- Support for IPv6 transport for AS lookup.
- Introduce $RA_SERVER to set whois server.
- Support for 4 byte ASN.
- ANSIfy function declaration in as.c.

Tested by: IHANet folks.

- rename the RETURN VALUES section to EXIT STATUS
- not bumping a date as this is not a real content change

Approved by: ru
MFC after: 3 days

Give traceroute6 the ability to traceroute with packets with no
upper layer header (IP PROTO = 59). Useful for testing firewalls.

MFC after: 2 months

- Fix: documentation for -m option was inserted halfway thru the text of -l
option.

PR: docs/90359
Submitted by: Gavin Atkinson <gavin.atkinson@ury.york.ac.uk>
MFC after: 3 days

Copy the description for the -r option from the traceroute(8) man
page. I'm pretty sure that this description applies the same way to
ipv6, and at least mentioning SO_DONTROUTE is better than having no
description at all.

Fixed the misplaced $FreeBSD$.

mdoc(7) fixes.

Add some more details about what traceroute6 does.

Submitted by: Orla McGann <orly@redbrick.dcu.ie>
Obtained from: KAME
MFC after: 2 weeks

Reapply traditionally lost fixes.

- setsockopt/sysctl takes int, not u_long.
- be more picky about argument parsing - like ERANGE.
- use u_long for args, not to lose accuracy/prevent overflow.
- socklen_t audit.
- Add -I (use icmp) option.
- warn if multiple addresses are present for dest.
- no need to pass tz.
- type pedant. check -p range.
- grab hlim from sysctl.
- typo in port number setting.

Obtained from: KAME

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: use the new features of the Nm macro.

Sync with latest KAME code.

Obtained from: KAME

Fix miscellaneous mdoc macro argument limit infringements.

PR: 18465
Reported by: Kazu TAKAMUNE <takamune@avrl.mei.co.jp>

Fix typo

Noticed by: hoek

. clear `.Os' macro value since this tool is not KAME only anymore
. add integration note
. avoid `.Nm' value upper case usage

Getaddrinfo(), getnameinfo(), and etc support in libc/net.
Several udp and raw apps IPv6 support.

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