From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEAF7423A71; Wed, 10 Jun 2026 15:13:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104441; cv=none; b=EYC4GYxr2+5hZHWgePdedtwrZNGJYZtTv8AdRkyQFmz8ov/4H0Kb3Uhq4Selm8lmH0m8Zq8Vcvinj2G1aesHH+4ODr17YDVvEgJ+/inG6TtlBEuNAIvXggJIXYZgrSR+ajI8CifG+oYtVl8xS18CNHYs8pKXOaAp2zFMBiEmYmA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104441; c=relaxed/simple; bh=+NO1vRXY1UCXrdbyf3AkYeqrkRUnllXlTaqS97pKD9M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FUyMjlYfBJzf7xsRozTb0gOvyCEYyPKv6puAHGL37Vu1qUe2xD8FQgqyKkewW7+deJCt+PXstjF7NwWDbzEec16oJhP+0yLRPX/i1a32H5Tt7/kXyvU+k2kMS/5Kjnq+HFeWm2YC7PxqR8dzdpUU/lgg2UMoPRnRPS9cDwA2HkU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U+HeB5D5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U+HeB5D5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CA041F00893; Wed, 10 Jun 2026 15:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781104439; bh=BpPa+YyaC3v2vRmGh7jdPoEYznbLVswalpX+n3AgG3Q=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=U+HeB5D57NI2DLIPj+baK0D1cq2T7EQ2uTTmVo20YufvR7IDq1MNGOsvizuXwNXCO s9qIR36Y+cMR1JEB1voV8XskgyUqL5Mtwj0UYw2UnaSsjGm7cZrRAH9olb+qHk5L01 vIdA1EzvbJFCbX8DdKVJ+yfeS1wy9CU0bHM0M9rk+4izFc3PbAwOChWVbbxatI0jgT FwR63Y3TDeO9zwcbX/pbQ04wURplxX7X8OGn216cnQ8PNfDiE7m2buuhHLS8tqSION eEd8ahoSXJlnA80S9oVlgkKxp33Cjna7s1OcGk8d5vJVRqJDbBDzTBLxtFkx0rQ9gI q7SJEPNoTNWzA== Message-ID: <17ecf803-4ee9-4dbc-ae9f-34da6460b163@kernel.org> Date: Wed, 10 Jun 2026 17:13:54 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net-next v2 06/15] mptcp: pm: drop TCP TS with ADD_ADDRv6 + port Content-Language: fr To: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260605-net-next-mptcp-add-addr6-port-ts-v2-0-758e7ca73f4d@kernel.org> <20260605-net-next-mptcp-add-addr6-port-ts-v2-6-758e7ca73f4d@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: <20260605-net-next-mptcp-add-addr6-port-ts-v2-6-758e7ca73f4d@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hello, On 05/06/2026 19:21, Matthieu Baerts (NGI0) wrote: > With TCP-timestamps (padded) taking 12 bytes and ADD_ADDR IPv6 + port > taking 30 bytes, the 40-byte limit for the TCP options is reached. In > this case, it is then not possible to send the signal. > > To be able to send this ADD_ADDR, the TCP timestamps option can now be > dropped. This is done, when needed by setting the *drop_ts parameter > from mptcp_established_options. This feature is controlled by a new > net.mptcp.add_addr_v6_port_drop_ts sysctl knob, enabled by default. > > It is important to keep in mind that dropping the TCP timestamps option > for one packet of the connection could eventually disrupt some > middleboxes: even if it should be unlikely, they could drop the packet > or even block the connection. That's why this new feature can be > controlled by a sysctl knob. FYI, Sashiko's new comments about this patch [1] are suggesting issues when MPTCP is used in parallel with TCP MD5. But MPTCP cannot be used with MD5 because there is not enough space in the TCP options. That's why there is an explicit rejection when initiating the connection. So I think we can ignore these comments saying that more options could be dropped, and the size can be negative. https://sashiko.dev/#/patchset/20260605-net-next-mptcp-add-addr6-port-ts-v2-0-758e7ca73f4d%40kernel.org?part=6 Cheers, Matt -- Sponsored by the NGI0 Core fund.