Linux Ethernet Bridging - Apr 2014 - [Bridge] [BUG?] bridge_id not getting set for bridges created with

Hi,

If IFLA_ADDRESS is set when creating a bridge over netlink, e.g.

# ip link add test-bridge address b6:83:a2:b3:2f:0e type bride

the bridge id is not set:

# brctl show
bridge name    bridge id        STP enabled    interfaces
bridge1        8000.000000000000    no


It looks like this is caused by br_stp_set_bridge_id never beeing
called. There appear to be many ways to solve this, but not sure what
is the preferred route...

Cheers,

Tom

On Mon, Apr 21, 2014 at 9:33 PM, Tom Gundersen <teg@jklm.no>
wrote:
> Hi,
>
> If IFLA_ADDRESS is set when creating a bridge over netlink, e.g.
>
> # ip link add test-bridge address b6:83:a2:b3:2f:0e type bride
>
> the bridge id is not set:
>
> # brctl show
> bridge name    bridge id        STP enabled    interfaces
> bridge1        8000.000000000000    no
My example was incomplete. To see the bug one should of course first
add an interface to the bridge:

# brctl addif bridge1 eth0


and observe that the bridge id remains unset:

# brctl show
bridge name    bridge id        STP enabled    interfaces
bridge1        8000.000000000000    no            eth0



If bridge1 had been created without specifying the mac address the
result is as expected:

# brctl show
bridge name    bridge id        STP enabled    interfaces
bridge1        8000.28d244547cdb    no            eth0

Cheers,

Tom

On Mon, Apr 21, 2014 at 9:33 PM, Tom Gundersen <teg at jklm.no>
wrote:
> Hi,
>
> If IFLA_ADDRESS is set when creating a bridge over netlink, e.g.
>
> # ip link add test-bridge address b6:83:a2:b3:2f:0e type bride
>
> the bridge id is not set:
>
> # brctl show
> bridge name    bridge id        STP enabled    interfaces
> bridge1        8000.000000000000    no
My example was incomplete. To see the bug one should of course first
add an interface to the bridge:

# brctl addif bridge1 eth0


and observe that the bridge id remains unset:

# brctl show
bridge name    bridge id        STP enabled    interfaces
bridge1        8000.000000000000    no            eth0



If bridge1 had been created without specifying the mac address the
result is as expected:

# brctl show
bridge name    bridge id        STP enabled    interfaces
bridge1        8000.28d244547cdb    no            eth0

Cheers,

Tom

On Mon, 2014-04-21 at 22:56 +0200, Tom Gundersen wrote:
> On Mon, Apr 21, 2014 at 9:33 PM, Tom Gundersen <teg at jklm.no>
wrote:
> > Hi,
> >
> > If IFLA_ADDRESS is set when creating a bridge over netlink, e.g.
> >
> > # ip link add test-bridge address b6:83:a2:b3:2f:0e type bride
> >
> > the bridge id is not set:
> >
> > # brctl show
> > bridge name    bridge id        STP enabled    interfaces
> > bridge1        8000.000000000000    no
> 
> My example was incomplete. To see the bug one should of course first
> add an interface to the bridge:
> 
> # brctl addif bridge1 eth0
> 
> 
> and observe that the bridge id remains unset:
> 
> # brctl show
> bridge name    bridge id        STP enabled    interfaces
> bridge1        8000.000000000000    no            eth0
> 
> 
> 
> If bridge1 had been created without specifying the mac address the
> result is as expected:
> 
> # brctl show
> bridge name    bridge id        STP enabled    interfaces
> bridge1        8000.28d244547cdb    no            eth0
> 
Hi.

This seems to be a bug.
What's worse is that local fdb entry won't be created and we will not be
able to receive frames on the bridge device...

rtnl_create_link() doesn't call ndo_set_mac_address but populates
dev->dev_addr by itself. I'm not sure if it is safe to call
ndo_set_mac_address in this function (maybe affects other drivers).  I
think this can be handled in bridge codes (br_link_ops->newlink).

I'm submitting a patch to fix this.

Thanks,
Toshiaki Makita