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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_NEOMUTT 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 E3D68C04AB6 for ; Sat, 1 Jun 2019 00:22:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BABD426FD8 for ; Sat, 1 Jun 2019 00:22:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726804AbfFAAWf (ORCPT ); Fri, 31 May 2019 20:22:35 -0400 Received: from mail.us.es ([193.147.175.20]:40736 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726518AbfFAAWf (ORCPT ); Fri, 31 May 2019 20:22:35 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 20FFDE2D9A for ; Sat, 1 Jun 2019 02:22:33 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 10A8DDA708 for ; Sat, 1 Jun 2019 02:22:33 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 06413DA706; Sat, 1 Jun 2019 02:22:33 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 0DB0DDA701; Sat, 1 Jun 2019 02:22:31 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Sat, 01 Jun 2019 02:22:31 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (sys.soleta.eu [212.170.55.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id DEAFE4265A31; Sat, 1 Jun 2019 02:22:30 +0200 (CEST) Date: Sat, 1 Jun 2019 02:22:30 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Stephen Suryaputra Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH nf-next] netfilter: add support for matching IPv4 options Message-ID: <20190601002230.bo6dhdf3lhlkknqq@salvia> References: <20190523093801.3747-1-ssuryaextr@gmail.com> <20190531171101.5pttvxlbernhmlra@salvia> <20190531193558.GB4276@ubuntu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190531193558.GB4276@ubuntu> User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Fri, May 31, 2019 at 03:35:58PM -0400, Stephen Suryaputra wrote: > On Fri, May 31, 2019 at 07:11:01PM +0200, Pablo Neira Ayuso wrote: > > > +/* find the offset to specified option or the header beyond the options > > > + * if target < 0. > > > + * > > > + * Note that *offset is used as input/output parameter, and if it is not zero, > > > + * then it must be a valid offset to an inner IPv4 header. This can be used > > > + * to explore inner IPv4 header, eg. ICMP error messages. > > > > In other extension headers (IPv6 and TCP options) this offset is used > > to match for a field inside the extension / option. > > > > So this semantics you describe here are slightly different, right? > > It is the same as the IPv6 one. The offset returned is the offset to the > specific option (target) or the byte beyond the options if the target > isn't specified (< 0). Thanks for explaining. So you are using ipv6_find_hdr() as reference, but not sure this offset parameter is useful for this patchset since this is always set to zero, do you have plans to use this in a follow up patchset? [...] > > > + if (tb[NFTA_EXTHDR_DREG]) > > > + return &nft_exthdr_ipv4_ops; > > > + } > > > + break; > > > > Then, from the _eval() path: > > > > You have to replace iph->version == 4 check abive, you could use > > skb->protocol instead, and check for htons(ETH_P_IP) packets. > > A bit lost. Did you mean this? > > static int ipv4_find_option(struct net *net, struct sk_buff *skb, > » » » unsigned int *offset, int target, > » » » unsigned short *fragoff, int *flags) > { > ... > » iph = skb_header_pointer(skb, *offset, sizeof(_iph), &_iph); > » if (!iph || skb->protocol != htons(ETH_P_IP)) > » » return -EBADMSG; I mean, you make this check upfront from the _eval() path, ie. static void nft_exthdr_ipv4_eval(const struct nft_expr *expr, ... { ... if (skb->protocol != htons(ETH_P_IP)) goto err; Thanks.