PF_RT_AF
snl_add_msg_attr_u8(nw, PF_RT_AF, r->af);
{ .type = PF_RT_AF, .off = _OUT(r.af), .cb = snl_attr_get_uint8 },
nlattr_add_u8(nw, PF_RT_AF, rule->af);
{ .type = PF_RT_AF, .off = _OUT(af), .cb = nlattr_get_uint8 },