Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Move the interface media check to a taskqueue, some interfaces (usb) sleep
during SIOCGIFMEDIA and we were holding locks.

Add linkstate to bridge(4), set the link to up when at least one underlying
interface is up, otherwise the link is down.

This, among other things, allows carp to work on a bridge.

Prodded by: glebius
Tested by: Alexander Lunev

bstp_input() always consumes the packet so remove the mbuf handling dance
around it.

Obtained from: OpenBSD (r1.37)

Set curvnet context in a callout-trigerred code path.

MFC after: 3 days

Fix spelling.

Obtained from: OpenBSD

- Ensure the path cost does not exceed 65535 in legacy STP mode.
- If the path cost is calculated when the link is down, set a pending flag so
it is calculated again when it comes back up.
- To not use 00:00:00:00:00:00 as the bridge id, all interfaces are scanned and
the lowest number wins. All zeros is too low.

Approved by: re (rwatson)

Change the passing of callbacks to a struct in case this needs to be extended in the future.

These days P2P means peer-2-peer (also well known from serveral filesharing
protocols) while PointToPoint has been PtP links. Change the variables
accordingly while the code is still fresh and undocumented.

Requested by: bz

Add two new flags to if_bridge(4) indicating whether the edge flag
of the bridge port and path cost have been administratively set or
calculated automatically by RSTP.

Make sure to transition from non-edge to edge when the port goes down
and the edge flag was manually set before.
This is needed to comply with the condition
((!portEnabled && AdminEdge) || ....)
in the Bridge Detection State Machine (IEE802.1D-2004, p. 171).

Reviewed by: thompsa
Approved by: bz (mentor)

fix typo in last commit

Use FreeBDS standard __packed as opposed to the gcc centric
__attribute__(__packed__).

Sync with the OpenBSD port of RSTP
- use flags rather than sperate ioctls for edge, p2p
- implement p2p and autop2p flags
- define large pathcost constant as ULL
- show bridgeid and rootid in ifconfig

Obtained from: Reyk Floeter <reyk@openbsd.org>

use two stage creation of stp ports, this means that the stp variables can be
set before the port is marked STP and they will no longer be overwrittten

MFp4
- Each stp port is added sequentially so it was possible for our bridgeid to
change every time because the new port has a lower MAC address. Instead
just find the lowest MAC address from all Ethernet adapters in the machine
as the value only needs to be unique, this stops a lot of churn on the
protocol.
- Update the states after enabling or disabling a port.
- Keep tabs if we have been stopped or started by our parent bridge.
- The callout only needs to be drained before destroying the mutex, move it to
bstp_detach.

Bring in support for the Rapid Spanning Tree Protocol (802.1w).

RSTP provides faster spanning tree convergence, the protocol will exchange
information with neighboring switches to quickly transition to forwarding
without creating loops. The code will default to RSTP mode but will downgrade
any port connected to a legacy STP network so is fully backward compatible.

Reviewed by: syrinx
Tested by: syrinx

Add a callback so we can notify the parent bridge that a port state change has
occured, we need to do this from a taskqueue to avoid a LOR with the if_bridge
mutex.

Add some statistics that are needed to support RFC4188 as part of the SoC2006
work on a bridge monitoring module for BSNMP.

Submitted by: shteryana (SoC 2006)

Forced commit due to missing log on the last revision.

Split the spanning tree state into its own structures and provide a simple API
to perform functions such as adding and deleting ports. This is just a
mechanical change and the STP operation remains the same. The bridgestp code
now has no knowledge of if_bridge.

This makes the code easier to read and can now also support other bridges such
as ng_bridge.

/tmp/cvsuusTrc