From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next 1/1] net/smc: add SMC rendezvous protocol Date: Thu, 12 Oct 2017 23:06:34 -0700 (PDT) Message-ID: <20171012.230634.24414822731374394.davem@davemloft.net> References: <20171011.140652.272274136617199385.davem@davemloft.net> <20171012111429.GG26835@breakpoint.cc> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20171012111429.GG26835@breakpoint.cc> Sender: netdev-owner@vger.kernel.org List-Archive: List-Post: To: fw@strlen.de Cc: ubraun@linux.vnet.ibm.com, netdev@vger.kernel.org, linux-s390@vger.kernel.org, jwi@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.vnet.ibm.com, hwippel@linux.vnet.ibm.com List-ID: From: Florian Westphal Date: Thu, 12 Oct 2017 13:14:29 +0200 > Ursula Braun wrote: >> On 10/11/2017 11:06 PM, David Miller wrote: >> > From: Ursula Braun >> > Date: Tue, 10 Oct 2017 16:14:19 +0200 >> > >> >> The goal of this patch is to leave common TCP code unmodified. Thus, >> >> it uses netfilter hooks to intercept TCP SYN and SYN/ACK >> >> packets. For outgoing packets originating from SMC sockets, the >> >> experimental option is added. For inbound packets destined for SMC >> >> sockets, the experimental option is checked. >> > >> > I think this really isn't going to pass. >> > >> > It's a user experience nightmare when the kernel inserts and >> > deletes filtering rules outside of what the user configures >> > on their system. > > It depends if the hook is passive or not (i.e. mangles > payload/metadata or returns verdict other than NF_ACCEPT). > > OUTPUT hook added here is not passive as it mangles tcp options. > >> > This approach was also considerd for ipv6 ILA, and the same >> > pushback was given. > > ahem. > net/ipv6/ila/ila_xlat.c: err = nf_register_net_hooks(net, ila_nf_hook_ops, My bad, I thought we had decided against that. Oh well.