From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF848C4338F for ; Tue, 10 Aug 2021 11:19:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2A3360EC0 for ; Tue, 10 Aug 2021 11:19:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238022AbhHJLTs (ORCPT ); Tue, 10 Aug 2021 07:19:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237252AbhHJLTr (ORCPT ); Tue, 10 Aug 2021 07:19:47 -0400 Received: from orbyte.nwl.cc (orbyte.nwl.cc [IPv6:2001:41d0:e:133a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 757F4C0613D3 for ; Tue, 10 Aug 2021 04:19:25 -0700 (PDT) Received: from n0-1 by orbyte.nwl.cc with local (Exim 4.94.2) (envelope-from ) id 1mDPn0-00029e-Pc; Tue, 10 Aug 2021 13:19:22 +0200 Date: Tue, 10 Aug 2021 13:19:22 +0200 From: Phil Sutter To: Florian Westphal Cc: Pablo Neira Ayuso , netfilter-devel@vger.kernel.org Subject: Re: [nft PATCH RFC] scanner: nat: Move to own scope Message-ID: <20210810111922.GD3673@orbyte.nwl.cc> Mail-Followup-To: Phil Sutter , Florian Westphal , Pablo Neira Ayuso , netfilter-devel@vger.kernel.org References: <20210809140141.18976-1-phil@nwl.cc> <20210809151833.GM607@breakpoint.cc> <20210809162514.GA3673@orbyte.nwl.cc> <20210809184559.GO607@breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210809184559.GO607@breakpoint.cc> Sender: Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Mon, Aug 09, 2021 at 08:45:59PM +0200, Florian Westphal wrote: > Phil Sutter wrote: > > > So, it is in IP scope, sees 'prefix' (which will be STRING as the > > > PREFIX scan rule is off) and that ends up in a parser error due to lack > > > of a 'IP STRING' rule. > > > > OK, thanks. So does this mean we won't ever be able to move keywords > > opening a statement or expression out of INIT scope or is my case a > > special one? > > We can move them out of INIT scope, but only if they remain within > the same scope. > > For example, you could create a 'rule scope' or 'expression scope' > that contains all tokens (ip, tcp, etc.) that start a new expression. Ah, OK! > I did not do this because there are too many cases where expressions are > permitted outside of rule scope, e.g. in set definitions (key, elements > ...) > > > To clarify, what I have in mind is a sample rule 'ip id 1 tcp dport 1' > > where 'tcp' must either be in INIT scope or part of SC_IP. > > IP and TCP need to be in the same scope (e.g. INIT). > > In the given example I suspect that TCP doesn't have to be in SC_IP > scope since 'ip id 1' is a full expression and scope closure happens > before next token gets scanned. Now I got it: The problem with nat_stmt is that 'snat ip' may either be 'SNAT nf_key_proto' or 'SNAT stmt_expr' and bison carries on until it's clear. I missed the fact that stmt_expr is allowed in nat_stmt_args. Thanks for the clarification! Maybe one day I'll finally understand how bison really works. %) Cheers, Phil