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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 EF3E0C43381 for ; Wed, 13 Mar 2019 14:15:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F40F214AE for ; Wed, 13 Mar 2019 14:15:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=riseup.net header.i=@riseup.net header.b="Us5JOME2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726130AbfCMOPr (ORCPT ); Wed, 13 Mar 2019 10:15:47 -0400 Received: from mx1.riseup.net ([198.252.153.129]:39422 "EHLO mx1.riseup.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725895AbfCMOPq (ORCPT ); Wed, 13 Mar 2019 10:15:46 -0400 Received: from bell.riseup.net (bell-pn.riseup.net [10.0.1.178]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*.riseup.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (verified OK)) by mx1.riseup.net (Postfix) with ESMTPS id E7C5F1A03FC; Wed, 13 Mar 2019 07:15:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=riseup.net; s=squak; t=1552486546; bh=0WNy7z2xHsWTOeJ2TNtFlV1CacvQHyrKC6Vv4EnrhbE=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From; b=Us5JOME2dlNxb+zY4vfm7jtnGKz9s8gs41tntmKGVeXVl1Aj9b7pt3sqzOeKOhcTj vS9vgsWZwXqdX8gtgAtENnYOcWWmiR5JNk98MGnJLeuea/dDRAGysu5BxJ+ZJfHzhz 8NzEuG5S9Mz0TxBuU3H1KGCKWnKhQiDpSdzrs0T4= X-Riseup-User-ID: 545CDC9AA2D78B1C05074210AFD2E92F34D74203280DBB3D538EE2EA682FC67E Received: from [127.0.0.1] (localhost [127.0.0.1]) by bell.riseup.net (Postfix) with ESMTPSA id 7C145221BB0; Wed, 13 Mar 2019 07:15:44 -0700 (PDT) Subject: Re: [PATCH nft v2 1/6] osf: add version fingerprint support To: Phil Sutter References: <20190311151417.17772-1-ffmancera@riseup.net> <20190313094424.GA11433@orbyte.nwl.cc> <20190313112733.GL4851@orbyte.nwl.cc> Cc: netfilter-devel@vger.kernel.org From: Fernando Fernandez Mancera Openpgp: preference=signencrypt Message-ID: Date: Wed, 13 Mar 2019 15:15:51 +0100 MIME-Version: 1.0 In-Reply-To: <20190313112733.GL4851@orbyte.nwl.cc> Content-Type: text/plain; charset=utf-8 Content-Language: en-US-large Content-Transfer-Encoding: 7bit Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On 3/13/19 12:27 PM, Phil Sutter wrote: > On Wed, Mar 13, 2019 at 11:14:04AM +0100, Fernando Fernandez Mancera wrote: >> Hi Phil, >> >> On 3/13/19 10:44 AM, Phil Sutter wrote: >>> Hi Fernando, >>> >>> On Mon, Mar 11, 2019 at 04:14:12PM +0100, Fernando Fernandez Mancera wrote: >>>> Add support for version fingerprint in "osf" expression. Example: >>>> >>>> table ip foo { >>>> chain bar { >>>> type filter hook input priority filter; policy accept; >>>> osf ttl skip name "Linux" >>>> osf ttl skip name version "Linux:4.20" >>>> } >>>> } >>> >>> The syntax seems overly complicated to me, although I'm not really >>> familiar with OSF so may lack background knowledge. Any reason why you >>> didn't go with 'osf ttl skip name "Linux" version "4.20"' instead? >>> >> >> You are right, 'osf ttl skip name "Linux" version "4.20"' was my first >> thought but in compilation time the parser applies shift-reduce to the >> expression.. I decided 'osf ttl skip name version "Linux:4.20"' to avoid >> a complex workaround in the parser. > > Shift/reduce warnings often require voodoo to fix, but it's not > impossible. :) > > Regarding my suggestion, I see that this string is actually the > right-hand-side of a relational expression. To implement what I had in > mind you would have to turn osf expression into a statement. > >> The fingerprints database syntax is "genre:version:subtype:details" so >> the nft 'osf' expression syntax is like the original one. > > Can we deduce required flags from the given string on RHS? I.e. by > looking at the amount of semi-colons and the number of characters > between them? I'm assuming the syntax works like "genre::subtype" and > "genre:::details" to omit certain parts, is that correct? > Yes that is correct. We can do that if you think it is more suitable. Do we all agree then? >>> Also with regards to your patch to json_parser, I guess you should >>> introduce an enum for flag values, something like: >>> >>> | enum osf_flags { >>> | OSF_FLAG_INVALID = 0x0, >>> | OSF_FLAG_VERSION = 0x1 >>> | }; >>> | >>> | const char *osf_flag_names[] = { >>> | [OSF_VERSION] = "version" >>> | }; >>> >>> What do you think? >>> >> >> This patch already introduces an enum for flags values, you can find it >> below. Do you think we need another one? Sorry if I am misunderstanding >> you. Thanks! > > Oh, I missed that one. My concern is how the index of values in > osf_flags array defined in osf_expr_json() and osf_flag_parse() is > relevant although it doesn't seem so when only looking at the array > definition. > Yes, we can use it in osf_expr_json(). I am going to work in a v3 patch series if it looks fine to you. Thanks! > Cheers, Phil >