label_get
assert(label_get(so_dest, so_pref) == NULL);
l = label_get(so_dest, so_pref);
struct label * label_get(const union sockunion *sodest,
lab = label_get(so_dest, so_pref);
if (label_get(so_dest, so_pref) == NULL) {
lab = label_get(so_dest, so_pref);