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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 3182BC4338F for ; Mon, 9 Aug 2021 15:18:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AB8960F93 for ; Mon, 9 Aug 2021 15:18:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233165AbhHIPS5 (ORCPT ); Mon, 9 Aug 2021 11:18:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232717AbhHIPS5 (ORCPT ); Mon, 9 Aug 2021 11:18:57 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6288C0613D3 for ; Mon, 9 Aug 2021 08:18:36 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1mD72v-0000yM-Ui; Mon, 09 Aug 2021 17:18:33 +0200 Date: Mon, 9 Aug 2021 17:18:33 +0200 From: Florian Westphal To: Phil Sutter Cc: Florian Westphal , Pablo Neira Ayuso , netfilter-devel@vger.kernel.org Subject: Re: [nft PATCH RFC] scanner: nat: Move to own scope Message-ID: <20210809151833.GM607@breakpoint.cc> References: <20210809140141.18976-1-phil@nwl.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210809140141.18976-1-phil@nwl.cc> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org 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.