kern/44374: bridge to interface with checksum offloading causes the interface to stop working

[explorer%flame.org@localhost]

>Number:         44374
>Category:       kern
>Synopsis:       bridge to interface with checksum offloading causes the 
>interface to stop working
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 12 07:30:00 +0000 2011
>Originator:     Michael Graff
>Release:        5.1_STABLE
>Organization:
>Environment:
NetBSD isc.home.flame.org 5.1_STABLE NetBSD 5.1_STABLE (XEN3_DOM0) #0: Sun Jan  
9 10:04:51 UTC 2011  
root%isc.home.flame.org@localhost:/usr/src/sys/arch/amd64/compile/XEN3_DOM0 
amd64
>Description:
If I enable checksum offloading on my "wm0" interface with:

  ifconfig wm0 ip4csum tcp4csum udp4csum tso4 tcp6csum udp6csum tso6

which enables all available offloading functions, when NetBSD configures the 
bridge with:

  create
  !brconfig $int add wm0 up

the interface stops receiving packets.  tcpdump shows traffic on the interface, 
and it appears transmitting packets continues to function.
>How-To-Repeat:

>Fix:
Disable all offloading functionality, and the interface works.