nlf_get_ifpz
int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target);
{ .off_in = _IN(ndm_ifindex), .off_out = _OUT(nda_ifp), .cb = nlf_get_ifpz },
{ .off_in = _IN(rtnh_ifindex), .off_out = _OUT(ifp), .cb = nlf_get_ifpz },