Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFhead r227901:

Fix parsing of redirect_addr argument.

PR: kern/162739

Approved by: re (kib)

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Actually, if code had followed style(9), there would be less stupid errors
like the one fixed in r223416.

Noticed by: julian

One more braino from me.

Pointy hat to: glebius
Submitted by: Alexander V. Chernikov <melifaro ipfw.ru>

- Fix my braino in the 220835, when I used strtok(). It isn't
applicable here, since modifies the string. Switch to strchr().
- Restore support for undocumented optional parameters of
redir_port and redir_proto, that were disabled in 220835.
- While here, change !isalpha() checks on optinal parameters
for isdigit().

Submitted by: Alexander V. Chernikov <melifaro ipfw.ru>
PR: kern/143653

Implement "global" mode for ipfw nat. It is similar to natd(8)
"globalport" option for multiple NAT instances.

If ipfw rule contains "global" keyword instead of nat_number, then
for each outgoing packet ipfw_nat looks up translation state in all
configured nat instances. If an entry is found, packet aliased
according to that entry, otherwise packet is passed unchanged.

User can specify "skip_global" option in NAT configuration to exclude
an instance from the lookup in global mode.

PR: kern/157867
Submitted by: Alexander V. Chernikov (previous version)
Tested by: Eugene Grosbein

Check nat id a bit more strictly.

Rewrite NAT configuration parser, so that memory allocation size is
calculated dynamically.

PR: kern/143653

More whitespace fixes.

Checked with: md5, diff -x -w

Whitespace fixes.

Checked with: md5, diff -w

remove some signed/unsigned and one const/!const warning

Add SCTP NAT support.

Submitted by: CAIA (http://caia.swin.edu.au)

put the altq-related functions into a separate file.
Minor cleanup of the includes used by the various source files,
including annotations of why certain headers are used.

Put nat and ipv6 support in their own files.

Usual moving of code with no changes from ipfw2.c to the
newly created files, and addition of prototypes to ipfw2.h

I have added forward declarations for ipfw_insn_* in ipfw2.h
to avoid a global dependency on ip_fw.h