[OpenWrt-Devel] Bridged interface MAC address changes during DHCP client transaction wtih netifd

Mark Mentovai mark at moxienet.com
Wed Jun 27 00:09:42 CEST 2012


Philip Prindeville wrote:
> On 6/26/12 11:02 AM, Jo-Philipp Wich wrote:
> > That is nothing netifd or OpenWrt does, it is the behaviour of Linux
> > bridges - they'll assume the lowest MAC address of all their member ifaces.
> > 
> > Imo that should be changed in the Kernel, it shoud fix the bridge MAC to
> > the one of the first member iface added, and then never change it again
> > even if the ports change.
> 
> I thought that used to be its behavior. Did that change? I remember 
> having similar issues both with wireless LANs bridged to ethernet, as 
> well as Ethernet bridged to DSL with PPPoE...
> 
> The old behavior was that the first interface to join the bridge would 
> set the bridge's address.

It looks like this used to be handled by the pre-netifd 
/lib/network/config.sh:

https://dev.openwrt.org/browser/trunk/package/base-files-network/files/lib/network/config.sh?rev=31979#L204

See line 232, where the bridge interface, when initially created, would be 
given the MAC address of its first member interface. That change was 
introduced in r26990:

https://dev.openwrt.org/changeset/26990

That would render the new (Linux kernel default) behavior of always making 
a bridge interface use the lowest MAC address of any member interface a 
regression introduced with the netifd change.


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