ng_bridge: do not move hosts from learnMac=0 hooksHEADmain

ng_bridge(4) says the node does not learn MAC addresses on uplink
hooks. However, learnMac was only checked when inserting a new
host. A host already known on a link hook was still moved if a
packet with that source address arrived on an uplink hook.

The nature of this is that inbound unicast to that host then
never arrives (the destination is known on the incoming hook).
Unknown unicast after timeout is still sent only to uplink, so
the host is not re-learned. The interface stays up and outbound
may still work. This can last minutes or weeks until reboot or
NGM_BRIDGE_MOVE_HOST.

Connecting ng_ether(4) lower to an uplink hook is enough: the
host's own transmit can appear on the uplink and the table entry
moves.

Use the same learnMac test for data-path move as for insert.
NGM_BRIDGE_MOVE_HOST from userland is unchanged.

MFC after:	1 week
Reviewed by:	jlduran
Differential Revision:	https://reviews.freebsd.org/D58902

0 files changed, 0 insertions, 0 deletions