From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4A6A1320A33; Wed, 5 Nov 2025 14:37:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762353431; cv=none; b=DztR3T0pQfeSdbdRDKxyPb8N/NgS/VmXwsU70Cf0tsE8UnmMvKDx+vdmc9CZtj59iAGBdmvXWscI7SWQ69ad69JCe2hbDVfGGMRD6WuTYUScFy5Q6H4ZGfQPVFDsofVCDoJhvpyM5xk1SEQ2JAr4XNWeW8044fTtZYkYTbgPU78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762353431; c=relaxed/simple; bh=Z5SbtMpM/KuQHHw5Ea+YCo1vcyY6brvzqA7sJIGK5EI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=a1ko1o02nvGvmuxjBAaCwh5lLhyyKrBS9G28Klr5/umZxPtP/Rf0vd769sBlMHtflswvBwJDgIJTnUwN6zzE+HsnVoWtZgU4Zm9lIUbTxBGm0gBix0idig52oOu+sX7aM1sfPdmgpfZt3M0K4bqo3Hh/voQWNAsj7V8MOM3JKHk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZQg2G6Zw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZQg2G6Zw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79221C4CEF5; Wed, 5 Nov 2025 14:37:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762353430; bh=Z5SbtMpM/KuQHHw5Ea+YCo1vcyY6brvzqA7sJIGK5EI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZQg2G6ZwBqsKwJRdiFkY/rYwCLGY/YnAR15qvZXZsuX4y0TDE4KR8dAsJ8J85IibG WLB2WTuVuiX6q8A8KJl/+PInySjninqSC4bIZS3GBKhEnr37ZwIA4DvDubyH3Amvi9 95DIQri8tt9HcZcLouoAWZS0NXhixQx81nsXp+ErxgUfH9VEjqj8SK4HcUdMl8wb4m z+dSi5X64yhHDoQh7xFX/5g1ju2IPSsgDwTp02koedPRcUEG4DvEtULFsvqU65UKCc /oDflTneqEOewy9E0YuhiMejfBaSk101uUPyS1Ex1izb/CiN9zWJqk1XHFvKioWDuA f5csU76CxNB7A== Message-ID: Date: Wed, 5 Nov 2025 15:37:01 +0100 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 v4 0/3] mptcp: Fix conflicts between MPTCP and sockmap Content-Language: en-GB, fr-BE To: Jiayuan Chen , mptcp@lists.linux.dev Cc: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Florian Westphal , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20251105113625.148900-1-jiayuan.chen@linux.dev> 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: <20251105113625.148900-1-jiayuan.chen@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Jiayuan, On 05/11/2025 12:36, Jiayuan Chen wrote: > Overall, we encountered a warning [1] that can be triggered by running the > selftest I provided. Thank you for the v4! > sockmap works by replacing sk_data_ready, recvmsg, sendmsg operations and > implementing fast socket-level forwarding logic: > 1. Users can obtain file descriptors through userspace socket()/accept() > interfaces, then call BPF syscall to perform these replacements. > 2. Users can also use the bpf_sock_hash_update helper (in sockops programs) > to replace handlers when TCP connections enter ESTABLISHED state > (BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB/BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB) > > However, when combined with MPTCP, an issue arises: MPTCP creates subflow > sk's and performs TCP handshakes, so the BPF program obtains subflow sk's > and may incorrectly replace their sk_prot. We need to reject such > operations. In patch 1, we set psock_update_sk_prot to NULL in the > subflow's custom sk_prot. This new version looks good to me. I have some small comments on patches 1 and 2 that can only be addressed if a v5 is needed I think. I have some questions for the 3rd patch. It would be good if someone else with more experience with the BPF selftests can also look at it. > Additionally, if the server's listening socket has MPTCP enabled and the > client's TCP also uses MPTCP, we should allow the combination of subflow > and sockmap. This is because the latest Golang programs have enabled MPTCP > for listening sockets by default [2]. For programs already using sockmap, > upgrading Golang should not cause sockmap functionality to fail. Note: even if these patches here are needed to avoid stream corruption and other issues, in your specific case with sockmap, I think it would be better to set this env var until MPTCP support is added to sockmap: GODEBUG=multipathtcp=0 Cheers, Matt -- Sponsored by the NGI0 Core fund.