PF_RT_CUID
snl_add_msg_attr_u32(nw, PF_RT_CUID, r->cuid);
{ .type = PF_RT_CUID, .off = _OUT(r.cuid), .cb = snl_attr_get_uint32 },
{ .type = PF_RT_CUID, .off = _OUT(cuid), .cb = nlattr_get_uint32 },
nlattr_add_u32(nw, PF_RT_CUID, rule->cuid);