it should never be a loopback interface.
* kame/sys/netinet6/in6.c (in6if_do_dad): was added to centralize the decision of whether DAD should be performed on a particular interface. This function is currently called from in6_update_ifa() and in6_ifattach_linklocal().
the decision of whether DAD should be performed on a particular interface.
assumed that long is equal on all architectures.
…efer net_osdep.h so that we have single place to update
the latter seems more intuitive.