K 10
svn:author
V 4
zlei
K 8
svn:date
V 27
2023-04-21T10:19:25.531922Z
K 7
svn:log
V 1003
bridge: Log MAC address port flapping

MAC flapping occurs when a bridge receives packets with the same source MAC
address on different member interfaces. The common reasons are:
 - user roams from one bridge port to another
 - user has wrong network setup, bridge loops e.g.
 - someone set duplicated ethernet address on his/her nic
 - some bad guy / virus / trojan send spoofed packets

if_bridge currently updates the bridge routing entry silently hence it is hard
to diagnose.

Emit logs when MAC address port flapping occurs to make it easier to diagnose.

Reviewed by:	kp
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D39375
Differential Revision:	https://reviews.freebsd.org/D39542

(cherry picked from commit 2d3614fb132b1cb8efd1e0accdd0c98ce6893efa)
(cherry picked from commit 9af6f4268ac3cc8203f34c746d955b4405279099)
(cherry picked from commit de53ebb0f20e9735a6167230eb38fd4695aa9c51)

Git Hash:   303d9a593bddb7e0d83c490052041b4c665f4b45
Git Author: zlei@FreeBSD.org
END