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

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

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

Approved by: re (implicit)

Keep the snmp_bridge(3) module up to date with if_bridge(4) and add an
object to control the value of the new 'PRIVATE' bridge members' flag.
While here, remove stale '__unused' compiler directives.

Reviewed by: bz
Approved by: re (bmah), bz (mentor)

Remove all #if __FreeBSD_version checks now that RSTP support has been
MFCed to RELENG_6. We no longer need that to compile the bridge module
under both RELENG_6 and CURRENT.

Approved by: bz (mentor)

bridge_snmp.h
* Change the API of bridge_get_basemac to take a maximum buffer length.

bridge_if.c
* Adopt to new API.
* In bridge_attach_newif() remove an additional pointer to the buffer
by shuffling the code a bit. Also makes the code more readable.

bridge_sys.c
* bridge_get_basemac():
- Adopt to the new API.
- Change check for error code of getifaddrs().
- First check for sa_family != AF_LINK.
- Copy sockaddr_dl * to get around alignment constraints on some
platforms.
- Use strcmp instead of strncmp so that "foo11" != "foo1".
* other functions:
- Allocate n times of the struct we need instead of arbitrary len,
cast to the type we want it to be and pass around struct *s instead
of char *s. This gets us around alignment restrictions on some
platforms and in addition it is more clear what data is passed around.
- Name variables for same types consistently.

Reviewed by: syrinx

Keep in sync with the if_bridge(4) module (rev. 1.20 if_bridgevar.h,
1.12 bridgestp.h) and rename all PointToPoint related variables
from P2P to PTP (s/P2P/PTP/g s/p2p/ptp/g).

Approved by: bz (mentor)

Do not add 'default:' cases inside a switch() on an enum like the
SNMP option argument. That way the compiler will give a warning in
case of a missing or an extra but unknown 'case:'.
Do the same for SNMP LEAF objects to be prepared once gensnmptree will
auto-generate enums for those too.
Add an abort() after the switch() instead of the 'default:' to catch
any errors. The nice side effect is that the compiler will correctly
track supposed to be 'uninitialized' variables with that.

When trying to set a value sanity check it before calling the OS
dependent API of snmp_bridge to tell whether it is an attempt to
set a bad value or a general error.

Suggested by: harti (first part)
Approved by: bz (mentor)

Add support for RSTP (RFC4318) to the SNMP bridge monitoring module.

Approved by: bz (mentor)

Bring in a SNMP module to support monitoring if_bridge(4) interfaces
via bsnmpd(1). The module implements IETF BRIDGE-MIB as defined in
RFC4188 and a private BEGEMOT-BRIDGE-MIB.

Sponsored by: Google Summer of Code 2006
Reviewed by: bz
Approved by: bz (mentor)