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 5ABBEC4338F for ; Mon, 9 Aug 2021 16:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38A6960041 for ; Mon, 9 Aug 2021 16:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232851AbhHIQZw (ORCPT ); Mon, 9 Aug 2021 12:25:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231478AbhHIQZq (ORCPT ); Mon, 9 Aug 2021 12:25:46 -0400 Received: from orbyte.nwl.cc (orbyte.nwl.cc [IPv6:2001:41d0:e:133a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80B84C0613D3 for ; Mon, 9 Aug 2021 09:25:17 -0700 (PDT) Received: from n0-1 by orbyte.nwl.cc with local (Exim 4.94.2) (envelope-from ) id 1mD85S-00005Q-2C; Mon, 09 Aug 2021 18:25:14 +0200 Date: Mon, 9 Aug 2021 18:25:14 +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: <20210809162514.GA3673@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210809151833.GM607@breakpoint.cc> Sender: Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Mon, Aug 09, 2021 at 05:18:33PM +0200, Florian Westphal wrote: > Phil Sutter wrote: > > Unify nat, masquerade and redirect statements, they widely share their > > syntax. > > This seemingly valid change breaks the parser with this rule: > > > > | snat ip prefix to ip saddr map { 10.141.11.0/24 : 192.168.2.0/24 } > > Yes. > > > Problem is that 'prefix' is not in SC_IP and close_scope_ip called from > > parser_bison.y:5067 is not sufficient. I assumed explicit scope closing > > would eliminate this lookahead problem. Did I find a proof against the > > concept or is there a bug in my patch? > > You have to keep 'prefix' in the global scope. > What should work as well is to permit 'prefix' from SCANSTATE_IP(6). > > The problem is that the parser can't close the new 'IP' scope until > it has enough tokens available to match a complete bison rule. > > 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? 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. Cheers, Phil