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 590761C8631; Fri, 23 May 2025 11:07:20 +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=1747998441; cv=none; b=DZEeVvKmEfl4plKe51kf/iBu1F/+Jwi47JB4GV3PtownUeKo3ZsIFxxdaG3edZjC4b9ctfAxPAKnO3KfwW/pT1ciwuzZ6NIpFK6XMwAAteESSXDwFdClHyKrR1Y0CVEy8YssumZVmk+Y8JXzsNP7u6JEECgC7nvxMvhHugupuxo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747998441; c=relaxed/simple; bh=ZtulG+GqmTItXJpWf8cI/7ZkLZKWayGN42QGW1nDVfA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Q01qroXWzYAe5BONzS5Cz+HeLATnjNl6yzqLb1vU/th2rv/6pNtxsIrO6ZMFKDVNDmyR4HXGroSF3Ow3N/dFoYLoJI88LAbX+ADCmumRU2yRDFiTnF8deFvcP+tUWcvRADzb4OBiKvF5jHtQ6h5b3O22Y/HkuBBlsg+EUxMEUt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qpSIwbb0; 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="qpSIwbb0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DE0EC4CEE9; Fri, 23 May 2025 11:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747998440; bh=ZtulG+GqmTItXJpWf8cI/7ZkLZKWayGN42QGW1nDVfA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qpSIwbb0KUSAPiEXVz6Eu1qPzh45BAEMErfL5Y8cbZjXSvlYLuPIzr/crAGWSKRqh kdmbU0wtTS+rbxvMhiEZlWuEOpIc22PYeg3JoD1dJl2wB7IpL4qrHHB1Dr1AbECQE+ KNex+SPzy1+HsM3x37ljDri1pFVk4YU02odvPc5/h2n21fsRt0l9gMxubobFeytHJc i20O8vkEyJaRb559fVGWXDB/5vP1+qn4YCUUH4QtHQPQSBXaeb5w6VZexPGEnMFxK3 34RML23GZbgJuJYEXEmehD5UUnwR9b+D2hXu/sY2j+1qum992Mnj20g44WSARuJB28 e1ICZQGgx4TDw== Message-ID: Date: Fri, 23 May 2025 13:07:10 +0200 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH bpf-next/net v3 4/5] selftests/bpf: Add mptcp_subflow bpf_iter subtest Content-Language: en-GB, fr-BE To: Martin KaFai Lau Cc: mptcp@lists.linux.dev, Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20250320-bpf-next-net-mptcp-bpf_iter-subflows-v3-0-9abd22c2a7fd@kernel.org> <20250320-bpf-next-net-mptcp-bpf_iter-subflows-v3-4-9abd22c2a7fd@kernel.org> <98348a02-9f8b-4648-8abe-e6b802ae9a63@linux.dev> <1621611c-8cf1-4281-986f-cfd8cc0e70f0@kernel.org> <0364f8d2-9aa5-4dc0-b7f6-1c8572932814@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: <0364f8d2-9aa5-4dc0-b7f6-1c8572932814@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Martin, On 21/05/2025 00:18, Martin KaFai Lau wrote: > On 5/19/25 3:04 AM, Matthieu Baerts wrote: >>>> +SEC("cgroup/getsockopt") >>>> +int iters_subflow(struct bpf_sockopt *ctx) >>>> +{ >>>> +    struct mptcp_subflow_context *subflow; >>>> +    struct bpf_sock *sk = ctx->sk; >>>> +    struct sock *ssk = NULL; >>>> +    struct mptcp_sock *msk; >>>> +    int local_ids = 0; >>>> + >>>> +    if (ctx->level != SOL_TCP || ctx->optname != TCP_IS_MPTCP) >>>> +        return 1; >>>> + >>>> +    msk = bpf_core_cast(sk, struct mptcp_sock); >>>> +    if (!msk || msk->pm.server_side || !msk->pm.subflows) >>>> +        return 1; >>>> + >>>> +    bpf_for_each(mptcp_subflow, subflow, (struct sock *)sk) { >>>> +        /* Here MPTCP-specific packet scheduler kfunc can be called: >>>> +         * this test is not doing anything really useful, only to >>> >>> Lets fold the bpf_iter_mptcp_subflow addition into the future >>> "mptcp_sched_ops" set (the github link that you mentioned in patch 2). >>> Post them as one set to have a more practical example. >> >> Thank you for this suggestion. We can delay that if needed. >> >> Note that we have two struct_ops in preparation: mptcp_sched_ops and >> mptcp_pm_ops. We don't know which one will be ready first. They are both >> "blocked" by internal API modifications we would like to do to ease the >> maintenance later before "exposing" such API's via BPF. That's why we >> suggested to upstream this common part first as it is ready. But we can >> of course wait if you prefer. > > This set is useful for discussing the questions you raised in patch 2. > > I still don't see it useful to upstream patch 2 alone. The existing > selftests/bpf/progs/mptcp_subflow.c has already shown a way to do > similar iteration in SEC("cgroup/getsockopt") without patch 2. > > I would prefer to wait for a fuller picture on the main struct_ops use > case first to ensure that we didn't overlook things. iiuc, improving the > iteration in SEC("cgroup/getsockopt") is not the main objective. I understand, that makes sense. When the rest will be ready, we will upstream patches from this series, except this one ("useless" selftest), and restricting bpf_iter_mptcp_subflow_* and other new kfuncs to BPF_PROG_TYPE_STRUCT_OPS only. So not to BPF_PROG_TYPE_CGROUP_SOCKOPT any more which was only needed for this new test. I don't think this program type requires access to these new kfunc for useful use-cases. This can be changed later if required anyway. >>>> +         * verify the iteration works. >>>> +         */ >>>> + >>>> +        local_ids += subflow->subflow_id; >>>> + >>>> +        /* only to check the following helper works */ >>>> +        ssk = mptcp_subflow_tcp_sock(subflow); >>>> +    } >>>> + >>>> +    if (!ssk) >>>> +        goto out; >>>> + >>>> +    /* assert: if not OK, something wrong on the kernel side */ >>>> +    if (ssk->sk_dport != ((struct sock *)msk)->sk_dport) >>>> +        goto out; >>>> + >>>> +    /* only to check the following kfunc works */ >>>> +    subflow = bpf_mptcp_subflow_ctx(ssk); >>> >>> bpf_core_cast should be as good instead of adding a new >>> bpf_mptcp_subflow_ctx() kfunc, so patch 1 should not be needed. >> >> OK, indeed, in this series we don't need it. We will need it later to >> modify some fields from the "subflow" structure directly. We can do the > > The "ssk" here is not a trusted pointer. Note that in patch 1, the kfunc > bpf_mptcp_subflow_ctx() does not specify KF_TRUSTED_ARGS. I suspect it > should be KF_TRUSTED_ARGS based on what you described here. Good point, I think this flag is indeed missing. Cheers, Matt -- Sponsored by the NGI0 Core fund.