From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: Re: [PATCH net-next] tc: bpf: add checksum helpers Date: Thu, 02 Apr 2015 09:34:59 -0700 Message-ID: <551D6FB3.7090304@plumgrid.com> References: <1427933533-14394-1-git-send-email-ast@plumgrid.com> <551D599F.30408@iogearbox.net> <20150402151530.GD2613@nanopsycho.orion> <551D5E69.4050704@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <551D5E69.4050704-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Daniel Borkmann , Jiri Pirko Cc: "David S. Miller" , Jamal Hadi Salim , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On 4/2/2015 8:21 AM, Daniel Borkmann wrote: > On 04/02/2015 05:15 PM, Jiri Pirko wrote: >> Thu, Apr 02, 2015 at 05:00:47PM CEST, daniel-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org wrote: >>> On 04/02/2015 02:12 AM, Alexei Starovoitov wrote: >>>> Commit 608cd71a9c7c ("tc: bpf: generalize pedit action") has added the >>>> possibility to mangle packet data to BPF programs in the tc pipeline. >>>> This patch adds two helpers bpf_l3_csum_replace() and >>>> bpf_l4_csum_replace() >>>> for fixing up the protocol checksums after the packet mangling. >>>> >>>> It also adds 'flags' argument to bpf_skb_store_bytes() helper to avoid >>>> unnecessary checksum recomputations when BPF programs adjusting l3/l4 >>>> checksums and documents all three helpers in uapi header. >>>> >>>> Moreover, a sample program is added to show how BPF programs can >>>> make use >>>> of the mangle and csum helpers. >>>> >>>> Signed-off-by: Alexei Starovoitov >>> >>> I think in future we need to find a better place for these helpers, >>> as they are for cls_bpf and act_bpf. >> >> Yeah, makes sense to now have it in net/core/filter.c. How about to >> create net/bpf dir for these? > > I was thinking somewhere under net/sched/, f.e. net/sched/bpf.c > as probably kernel/bpf/ would end up in too much ifdef pasta. :/ I would prefer to keep mangle and csum helpers in net/core/filter.c for now, since it's not clear what networking subsystems beyond TC would want to use them in the future. Otherwise we'll keep moving them back and forth.