PF_AA_AF
snl_add_msg_attr_u8(&nw, PF_AA_AF, pa->af);
{ .type = PF_AA_AF, .off = _OUT(af), .cb = snl_attr_get_uint8 },
{ .type = PF_AA_AF, .off = _OUT(af), .cb = nlattr_get_uint8 },
nlattr_add_u8(nw, PF_AA_AF, attrs.af);