From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] netfilter: xt_TCPMSS: handle CHECKSUM_COMPLETE in tcpmss_tg6() Date: Fri, 15 Jan 2016 14:04:49 -0500 (EST) Message-ID: <20160115.140449.1324683966791337294.davem@davemloft.net> References: <1452874892.1223.175.camel@edumazet-glaptop2.roam.corp.google.com> <1452878324.1223.188.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: tom@herbertland.com, pablo@netfilter.org, kaber@trash.net, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, herbert@gondor.apana.org.au To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:60587 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750802AbcAOTEx (ORCPT ); Fri, 15 Jan 2016 14:04:53 -0500 In-Reply-To: <1452878324.1223.188.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netfilter-devel-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Fri, 15 Jan 2016 09:18:44 -0800 > On Fri, 2016-01-15 at 08:43 -0800, Tom Herbert wrote: > >> Probably should have a utility function do this. Maybe something like >> update_hdr_field(skb, old, new)? Could return new value so above could >> just be: >> >> ipv6h->payload_len = update_hdr_field(skb, ipv6h->payload_len, >> htons(ntohs(oldlen) + ret); > > Well, oldlen would still need to be ipv6h->payload_len > > Not sure a helper will be nice for a stable submission. > > Probably better for net-next ? Agreed. We already have those csum_replace{2,4}() helpers in net/checksum.h which we could augment with ones that can handle length changes too.