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[146.241.113.89]) by smtp.gmail.com with ESMTPSA id c10-20020a7bc00a000000b003942a244edcsm1647311wmb.33.2022.05.11.03.22.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 May 2022 03:22:21 -0700 (PDT) Message-ID: <2bf857cc4abe21426ce2418645667663ca7cefcb.camel@redhat.com> Subject: Re: [PATCH mptcp-next v2] mptcp: fix checksum byte order From: Paolo Abeni To: Mat Martineau Cc: mptcp@lists.linux.dev Date: Wed, 11 May 2022 12:22:20 +0200 In-Reply-To: <331ef61b-19b7-ea0-6832-ebf3c97aa9c@linux.intel.com> References: <595f104803a212df58db6d20f84947325b33a9d6.1652196378.git.pabeni@redhat.com> <331ef61b-19b7-ea0-6832-ebf3c97aa9c@linux.intel.com> User-Agent: Evolution 3.42.4 (3.42.4-2.fc35) Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pabeni@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit On Tue, 2022-05-10 at 16:10 -0700, Mat Martineau wrote: > On Tue, 10 May 2022, Paolo Abeni wrote: > > > The MPTCP code typecasts the checksum value to u16 and > > then convert it to big endian while storing the value into > > the MPTCP option. > > > > As a result, the wire encoding for little endian host is > > wrong, and that causes interoperabilty interoperability > > issues with other implementation or host with different endianess. > > > > Address the issue writing in the packet the unmodified __sum16 value. > > > > MPTCP checksum is disabled by default, interoperating with systems > > with bad mptcp-level csum encodying should cause fallback to TCP. > > > > Fixes: c5b39e26d003 ("mptcp: send out checksum for DSS") > > Fixes: 390b95a5fb84 ("mptcp: receive checksum for DSS") > > Signed-off-by: Paolo Abeni > > --- > > v1 -> v2: > > - move the typecast inside put_len_csum (Mat) > > - updated the commit message (Mat) > > - fix a few sparse issues > > Hi Paolo, thanks for the v2: > > Reviewed-by: Mat Martineau > > (for export-net) > > Still ok with you to apply this to export-net? There are a couple of minor > conflicts when rebasing to export-net, and it also creates a merge > conflict with net-next. But I think it's worth it to be able to say "every > 5.18 and later kernel has the checksum fix". Agreed. > Have you tried backporting this commit to 5.17-stable or 5.15-stable? No, that is likely worthy, but I really have my hands full :( I think I can have a look not earlier than next week. /P