Bridge's communicate with each other using Spanning Tree Protocol
over a standard multicast address. There are times when testing or
layering bridges over existing topologies or tunnels, when it is
useful to use alternative multicast addresses for STP packets.

The 802.1d standard has some unused addresses, that can be used for this.
This patch is restrictive in that it only allows one of the possible
addresses in the standard.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use LLC for the receive path of Spanning Tree Protocol packets.
This allows link local multicast packets to be received by
other protocols (if they care), and uses the existing LLC
code to get STP packets back into bridge code.

The bridge multicast address is also checked, so bridges using
other link local multicast addresses are ignored. This allows
for use of different multicast addresses to define separate STP
domains.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cleanup the get/set of bridge timer value in the packets.
It is clearer not to bury the conversion in macro.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Change Bridge receive path to correctly handle RCU removal of device
from bridge.  Also fixes deadlock between carrier_check and del_nbp.
This replaces the previous deleted flag fix.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid poisoning of the bridge forwarding table by frames that have been
dropped by filtering. This prevents spoofed source addresses on hostile
side of bridge from causing packet leakage, a small but possible security
risk.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!