EUI64_GBIT
if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
ifra.ifra_addr.sin6_addr.s6_addr[8] &= ~EUI64_GBIT;
#define EUI64_GROUP(in6) ((in6)->s6_addr[8] & EUI64_GBIT)
in6->s6_addr[8] &= ~EUI64_GBIT; /* g bit to "individual" */