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 7B96FC43381 for ; Wed, 13 Mar 2019 16:46:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 464D8206DF for ; Wed, 13 Mar 2019 16:46:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=riseup.net header.i=@riseup.net header.b="U7nYUpve" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726142AbfCMQqB (ORCPT ); Wed, 13 Mar 2019 12:46:01 -0400 Received: from mx1.riseup.net ([198.252.153.129]:50642 "EHLO mx1.riseup.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725856AbfCMQqB (ORCPT ); Wed, 13 Mar 2019 12:46:01 -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 8627E1A55BA; Wed, 13 Mar 2019 09:46:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=riseup.net; s=squak; t=1552495560; bh=3pU1aDhzlKfyeUv0OPAx6csTvr20RQkMITppST8DnqE=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From; b=U7nYUpveFOsKbRgiSSM12PcS3LOT6cLsPBQy4ltrBRnhCVbGxgkYYQImzUqgvZxAo ZsWr49MUKL7mR1D+AVqu7tDeRJZkpktp8oTYUEfJF4zsihKZe8dwOdJU17XwfpCZGi 68XXx4pKi7IiTGAO5w32BRFuK2JfIOvVttOAsgPU= X-Riseup-User-ID: C77077FA6770E89B5887791D59D9D822E1B1ED9BB9D1B56D0318B213BBBC9BFF Received: from [127.0.0.1] (localhost [127.0.0.1]) by bell.riseup.net (Postfix) with ESMTPSA id 3CD22222132; Wed, 13 Mar 2019 09:45:59 -0700 (PDT) Subject: Re: [PATCH nft v2 1/6] osf: add version fingerprint support To: Phil Sutter , Pablo Neira Ayuso References: <20190311151417.17772-1-ffmancera@riseup.net> <20190313094424.GA11433@orbyte.nwl.cc> <20190313112733.GL4851@orbyte.nwl.cc> <20190313150634.GM4851@orbyte.nwl.cc> <2b070950-1441-ae1b-fe52-72dc7bc4455e@riseup.net> <20190313153455.GN4851@orbyte.nwl.cc> Cc: netfilter-devel@vger.kernel.org From: Fernando Fernandez Mancera Openpgp: preference=signencrypt Message-ID: Date: Wed, 13 Mar 2019 17:46:06 +0100 MIME-Version: 1.0 In-Reply-To: <20190313153455.GN4851@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 4:34 PM, Phil Sutter wrote: > On Wed, Mar 13, 2019 at 04:22:27PM +0100, Fernando Fernandez Mancera wrote: >> On 3/13/19 4:06 PM, Phil Sutter wrote: >>> Hi Fernando, >>> >>> On Wed, Mar 13, 2019 at 03:15:51PM +0100, Fernando Fernandez Mancera wrote: >>>> 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? >>> >>> I think reducing redundancy is always a good thing. Only having to >>> specify the string and extracting the required info from it would make >>> it easier for users I guess. >>> >>> That whole string is sent to the kernel, right? So it wouldn't make >>> sense to split the fields it is made up from into separate properties in >>> JSON, correct? >>> >>> Thanks, Phil >>> >> >> Yes, that makes sense. In this case, we don't need flags support anymore >> so it reduces the patch series. Should we continue with the >> implementation of the flags support or just forget about it until needed >> again? > > What other flags do you have in mind? > > Cheers, Phil > Maybe in the future we could need them for logging. But we can ignore it right now.