On 2-3-2012 15:49, Matthieu Herrb wrote:
> On Fri, Mar 02, 2012 at 03:19:34PM +0100, Camiel Dobbelaar wrote:
>> I think the bridge loop detection in if_ethersubr.c can be removed.  It 
>> taxes all bridge output traffic, but I don't think it ever kicks in.
>>
>> It was added in 2001 by angelos:
>> http://www.openbsd.org/cgi-bin/cvsweb/src/sys/net/if_ethersubr.c.diff?r1=1.48;r2=1.49;f=h
>>
>> I'd say the following ethertypes are safe, they push packets further down 
>> the stack so they cannot be bridged again: ieee80211, trunk, vlan
>>
>> tun and gre cannot be part of a bridge.
> 
> While I don't understand the network stack very deeply, I for sure
> have tun interfaces (in tap mode, with link0 set) part of a bridge on
> my openvpn gateway:
> 
> bridge0: flags=41<UP,RUNNING>
>         groups: bridge
>         priority 32768 hellotime 2 fwddelay 15 maxage 20 holdcnt 6
>         proto rstp
>         tun0 flags=3<LEARNING,DISCOVER>
>                 port 14 ifpriority 0 ifcost 0
>         vlan4 flags=3<LEARNING,DISCOVER>
>                 port 6 ifpriority 0 ifcost 0
> 
> 
> 

Yes, you are right, I missed the layer-2 tap mode.  It looks like it
only pushes packets further down as well (so they cannot be bridged
twice).  But the tun code is a little more challenging so not 100% sure yet.

If you can try the diff on this setup, that would be nice.

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