IPIF_PREFERRED
{ "PREF", IPIF_PREFERRED, IPIF_PREFERRED},
bc->cand_ispreferred = ((bc->cand_flags & IPIF_PREFERRED) != 0);
cc->cand_ispreferred = ((cc->cand_flags & IPIF_PREFERRED) != 0);
ILLF_NONUD|IPIF_PRIVATE|IPIF_ANYCAST|IPIF_PREFERRED|