From patchwork Tue Sep 10 14:12:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthieu Baerts (NGI0)" X-Patchwork-Id: 13798584 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 5EBEC188CBB; Tue, 10 Sep 2024 14:13:26 +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=1725977606; cv=none; b=I4th1KCfX1HRVs5fxZXI6qlOa3A468ELfuBYQDCSgiQrA9OAM/+O3EoSK14KN4VEsiQo3qKCvkXyz1CSb/j1/viEzStNkFw6GYP5/hTogsjcpGWfXQsimjBHcEH0d00YeybCcQ03EENhuL4zh/YkfonzeUzG/SChlQyED4v8eKg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725977606; c=relaxed/simple; bh=hWl57FHY2fOdoggMMQbYWWGMnt4b33OvRJbD5uuAWPQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=GUiXSMUPt8XidyV3mn+ZAdRdRwTbI0s3fPhjgzDhA16monBb3Nb2ccvtxijPwxaeg5lmI7pAQjadW2D2SAh2/HTE99KQfby8hqCWT1muLTNjGy9f26RVXafFkPnBjtVAhXY/KrD/8ctFyMMyts7Ph9ihfaldI4d8oif/Dgjy6uI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IgBirhhN; 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="IgBirhhN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EDB9C4CED1; Tue, 10 Sep 2024 14:13:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725977606; bh=hWl57FHY2fOdoggMMQbYWWGMnt4b33OvRJbD5uuAWPQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=IgBirhhNDnr0wa9pmkekuaGVxwMzodpWsGehEC9qffQv+Ps/3zJJlN40itLpzyDLb p1JTUlbNtPqYCi+I82F6fty5FKOihR0LuBCdcgdNuJFKJYDQguUnN8RzxR3PpSEIGH JT9VAQuYmDQbxHOLLA8HArKaJ77fIIG2WIq7IUgrZhbXyVBwkhIpKfJ0k8qjY5iXtJ 4tmaVXOtEcMRXuy2ZlAjlRz3NkQHE6is5INMjgLFEGSAxepoHAP7MFaNM1+zf82Bat lFA8m7lBSHU0ULoK8OvmXHUHHhJGJlqWLv4iHLSAYjy1iNGk10gRRMmkfYAMn/2UOo zTAVDFKyv7jBA== From: "Matthieu Baerts (NGI0)" Date: Tue, 10 Sep 2024 16:12:59 +0200 Subject: [PATCH bpf-next/net v5 1/3] selftests/bpf: Add mptcp subflow example Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240910-upstream-bpf-next-20240506-mptcp-subflow-test-v5-1-2c664a7da47c@kernel.org> References: <20240910-upstream-bpf-next-20240506-mptcp-subflow-test-v5-0-2c664a7da47c@kernel.org> In-Reply-To: <20240910-upstream-bpf-next-20240506-mptcp-subflow-test-v5-0-2c664a7da47c@kernel.org> To: mptcp@lists.linux.dev, Mat Martineau , Geliang Tang , Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, "Matthieu Baerts (NGI0)" , Nicolas Rybowski , Geliang Tang X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=4445; i=matttbe@kernel.org; h=from:subject:message-id; bh=98MxbfTkgjSKHUOjjCbtRcgcjpjaNf9HbvOObpvAYhI=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBm4FP6OAgCr/76qaOirF0W9fH+xWuZwyjL1P1Di kaSlJekI1mJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZuBT+gAKCRD2t4JPQmmg c/YyEAC4I+ya+HE9RLuO9qLM8XrXnxmGObKEYeJJdZXW7utQnr784IXI//tGO6gyOXEBUfAcmOa bkohR1J7mrIMLfiAG30A4ZV0tQSFWXV3ruHZInBxkKula3Vm3wuRvIoqr2UZufVBBKBuBtEvTrR XAmvPRZiML4/zPg45m2P0DfAuHKKEwxd3hLoqTu9ahzYAQEqDsPvVdFCwjAxZTum1060WnhpGzf hjEJvK/1xI0iyvkf54OUQc8O2sHfXkSYrU8zNYBx+UhyTj3/c6wdkZevkeFGi02dvJdYQ5J+Km8 MPar6jDk+Hz1Z56Ggz8gHuDelQQ0BWmm6XJP9zgj6B0zl8DZZqVNjGrMvH2Xflw8XrRXo2a+P5u sNZKxK43Y5nw7vQmHzJ5ehcRA5pfbKV84MH9wVddgzUaLYYS0sE9KD5pmjdYRHDpX9J+oZCiLYh 03uD0h0PIOiBrX9YO0oVRxC7Dr2IxbSz+N5Vs0C652f8ya23LUfxbYvWzagxdios7bg+i7nEcT4 +qtu0Utwq2Ns/ccOakO087fUYvOjkdc+foCBbsQR0YBa8/F5BEeXZE9oVO2n9axEFDo5CCQsFfK Wf4Vt4862yfZ1u1rmLDf8yOHTyi4T1fjuSr/ihqgbttlj/fwW/j64ZKp/jjB+fjN22a53r7OjhJ ZnF1I0cLKPYRi+A== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Nicolas Rybowski Move Nicolas' patch into bpf selftests directory. This example adds a different mark (SO_MARK) on each subflow, and changes the TCP CC only on the first subflow. From the userspace, an application can do a setsockopt() on an MPTCP socket, and typically the same value will be propagated to all subflows (paths). If someone wants to have different values per subflow, the recommended way is to use BPF. So it is good to add such example here, and make sure there is no regressions. This example shows how it is possible to: Identify the parent msk of an MPTCP subflow. Put different sockopt for each subflow of a same MPTCP connection. Here especially, two different behaviours are implemented: A socket mark (SOL_SOCKET SO_MARK) is put on each subflow of a same MPTCP connection. The order of creation of the current subflow defines its mark. The TCP CC algorithm of the very first subflow of an MPTCP connection is set to "reno". This is just to show it is possible to identify an MPTCP connection, and set socket options, from different SOL levels, per subflow. "reno" has been picked because it is built-in and usually not set as default one. It is easy to verify with 'ss' that these modifications have been applied correctly. That's what the next patch is going to do. Nicolas' code comes from: commit 4d120186e4d6 ("bpf:examples: update mptcp_set_mark_kern.c") from the MPTCP repo https://github.com/multipath-tcp/mptcp_net-next (the "scripts" branch), and it has been adapted by Geliang. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/76 Co-developed-by: Geliang Tang Signed-off-by: Geliang Tang Signed-off-by: Nicolas Rybowski Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) --- Notes: - v1 -> v2: - The commit message has been updated: why setting multiple socket options, why reno, the verification is done in a later patch (different author). (Alexei) - v2 -> v3: - Only #include "bpf_tracing_net.h", linked to: https://lore.kernel.org/20240509175026.3423614-1-martin.lau@linux.dev - v4 -> v5: - Set reno as TCP cc on the second subflow, not to influence the getsockopt() done from the userspace, which will return the one from the first subflow, the default TCP cc then, not the modified one. --- tools/testing/selftests/bpf/progs/mptcp_subflow.c | 59 +++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/mptcp_subflow.c b/tools/testing/selftests/bpf/progs/mptcp_subflow.c new file mode 100644 index 000000000000..2e28f4a215b5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/mptcp_subflow.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020, Tessares SA. */ +/* Copyright (c) 2024, Kylin Software */ + +/* vmlinux.h, bpf_helpers.h and other 'define' */ +#include "bpf_tracing_net.h" + +char _license[] SEC("license") = "GPL"; + +char cc[TCP_CA_NAME_MAX] = "reno"; + +/* Associate a subflow counter to each token */ +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u32)); + __uint(max_entries, 100); +} mptcp_sf SEC(".maps"); + +SEC("sockops") +int mptcp_subflow(struct bpf_sock_ops *skops) +{ + __u32 init = 1, key, mark, *cnt; + struct mptcp_sock *msk; + struct bpf_sock *sk; + int err; + + if (skops->op != BPF_SOCK_OPS_TCP_CONNECT_CB) + return 1; + + sk = skops->sk; + if (!sk) + return 1; + + msk = bpf_skc_to_mptcp_sock(sk); + if (!msk) + return 1; + + key = msk->token; + cnt = bpf_map_lookup_elem(&mptcp_sf, &key); + if (cnt) { + /* A new subflow is added to an existing MPTCP connection */ + __sync_fetch_and_add(cnt, 1); + mark = *cnt; + } else { + /* A new MPTCP connection is just initiated and this is its primary subflow */ + bpf_map_update_elem(&mptcp_sf, &key, &init, BPF_ANY); + mark = init; + } + + /* Set the mark of the subflow's socket based on appearance order */ + err = bpf_setsockopt(skops, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)); + if (err < 0) + return 1; + if (mark == 2) + err = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION, cc, TCP_CA_NAME_MAX); + + return 1; +}