nd_ra_flags_reserved
ra->nd_ra_flags_reserved = 0; /* just in case */
ra->nd_ra_flags_reserved = 0xff & rainfo->rtpref;
ra->nd_ra_flags_reserved |=
ra->nd_ra_flags_reserved |=
if ((ra->nd_ra_flags_reserved & ND_RA_FLAG_MANAGED) !=
if ((ra->nd_ra_flags_reserved & ND_RA_FLAG_OTHER) !=