From: YOSHIFUJI Hideaki <redacted>
Date: Tue, 29 Aug 2006 18:34:26 +0900 (JST)

Further analysis is needed, but one idea is to skip
addrconf_dev_config() if !(dev->flags & IFF_MULTICAST).

Yes, it is logical because without multicast IPV6 cannot
work correctly.

But from another perspective (I assume these bridged Xen devices use
ARPHRD_ETHER, do they?) a device with ARPHRD_ETHER and cleared
IFF_MULTICAST flag seems potentially problematic.  How many other
things break over such a device?