From patchwork Tue Sep 10 14:13:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthieu Baerts X-Patchwork-Id: 13798593 X-Patchwork-Delegate: matthieu.baerts@tessares.net 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 2FF36188CBB; Tue, 10 Sep 2024 14:13:31 +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=1725977611; cv=none; b=Gc65cN+VaFMLTpXVhZBsWjtmoqraJ/FrBYNAEpDqJHavqcUXc+uHUA6T20ZY25SlHnaLfC68RCa+Rdd6OaDv+krOCevlxyUkAC9+wFbyOnwpOkhW6Lpu26nJ6VGUaaXm6Kt+fBBI97fKLDm0ynw4qpmWJLShKWnPT9JZnEoiUQ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725977611; c=relaxed/simple; bh=Iv5TZEml/H6t7GaDZCEGZTMq7nkqIaIE/iw0KKiXtKo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=piWq95QVZwdGkHmyUbaiIHgWkTdkxpHeoyKIajrfO/LAjEY7uSAb/g7RO78OMExR4gvjdRYfhVpkANbVbDX3sdCIdS6MaAr2P2lYGEZw3qpLZ+VonC4Ek2L4fP57wUSoez84xyyJA6cqiu7fIXnNpbAbAEE5HrjWNe2vlgyyDgc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jS2b/pyC; 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="jS2b/pyC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81C9FC4CED2; Tue, 10 Sep 2024 14:13:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725977611; bh=Iv5TZEml/H6t7GaDZCEGZTMq7nkqIaIE/iw0KKiXtKo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=jS2b/pyCzUcgYPyHpg3WdNpOIRrXKr+rtT1OJwtziK8/h68Cg2PQu2NEgF8JNEnY+ ++jhom7vQSGIaLiA6EpIqG7tIT1n6hBD4I475KErWBLV39p10M1Lnfq10rkS70+R4m q/UDlRVWUItQeAoCzmvbYZghyFeOxHNmqzkVcRlxt3ckvr24wKOIkPMFZGIRtoI6kp k3EI7UEkGVzpOEGZfvVxEsvw4LGNG5+VmlJ3IHZIRo8S104yIhifqQavKTgoCrzMOn IbJYOU1daXp7ZTYDx2EpEkf4cgQp+8uBfMoCgseg5/ePqnGOrdTwiHEL9WQQfhi29I 8xD92KaUQ1iuw== From: "Matthieu Baerts (NGI0)" Date: Tue, 10 Sep 2024 16:13:00 +0200 Subject: [PATCH bpf-next/net v5 2/3] selftests/bpf: Add getsockopt to inspect mptcp subflow Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240910-upstream-bpf-next-20240506-mptcp-subflow-test-v5-2-2c664a7da47c@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)" , Martin KaFai Lau , Geliang Tang X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=6005; i=matttbe@kernel.org; h=from:subject:message-id; bh=FDhxqzjJz67+rEBh+dkc4FV5Kx80WdtuXY//a+1arxA=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBm4FP6PWb5L7K5OOzY7au9d3x/3Hvk2v60gTqqY Bv9MPDaWBeJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZuBT+gAKCRD2t4JPQmmg czZVD/9qboRpOedgzfsOTqY1wEOI8cgvLCZiKvxXfdhlDVNstUtgNLU7dXTB7J4g+at6SnS1xGz 8m36NXSobVs1bQRhlZX6tyWF6ng8x+LQQWvzOzOq9LMY2P7QCny5aTMdJzjdJX3L5aDVSowGe6/ Lrs8BVyqLX62rkiouMLxCSX3RIkxNykQ0h4y1Rne+RS0JYUuKZl2wnzUi0DxK4KuuNqpkSYYD/S OW2rBrvecA85G/yMG2eWlrgGWknze0MlPcbG+WXwmKFBFPIjMdD6PRZ0cWCE6l+97mx6hkjhCfF rBU5ZOqNUxs3CJKO+5J7hp1mmScwMnCsnHnbHK7PGBYksfzjS94pszRX6K1U7AlyZDLTUNhpY4v B4ovQKcr9zAseXa+lFLLh7peTlfFqbCf+kq6qDUCCKJl8wJWOUlJ28miU6j+iXJCe/bohOTDU7e DZk4SbsFS1I4o359JJV3Avz7kj/ziWV/fBdF/M++bxR45auCHDkmAVpl63a/9zCiOKDLN7Ul0Hv ZGswauwSTyJaTG7/UJ1pWe4cMVrNXfjiqs89vG3hdwbQpA17MtV8tkmOUKC3rq8Blw9Hs7iWDod omawYdkU73hAc64BQ2FlCxvagm8pvpRz+Hd8hq533K1zDBekUxqhLIUEP1bdsCHFCGv6DTUrYvn mR2TS+LJkcn9Jrw== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Geliang Tang This patch adds a "cgroup/getsockopt" way to inspect the subflows of an MPTCP socket, and verify the modifications done by the same BPF program in the previous commit: a different mark per subflow, and a different TCP CC set on the second one. This new hook will be used by the next commit to verify the socket options set on each subflow. This extra "cgroup/getsockopt" prog walks the msk->conn_list and use bpf_core_cast to cast a pointer for readonly. It allows to inspect all the fields of a structure. Note that on the kernel side, the MPTCP socket stores a list of subflows under 'msk->conn_list'. They can be iterated using the generic 'list' helpers. They have been imported here, with a small difference: list_for_each_entry() uses 'cond_break' to limit the number of iterations, and ease its use. Because only data need to be read here, it is enough to use this technique. It is planned to use bpf_iter, when BPF programs will be used to modify data from the different subflows. mptcp_subflow_tcp_sock() and mptcp_for_each_stubflow() helpers have also be imported. Suggested-by: Martin KaFai Lau Signed-off-by: Geliang Tang Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) --- Notes: - v5: new patch, instead of using 'ss' in the following patch --- MAINTAINERS | 2 +- tools/testing/selftests/bpf/progs/mptcp_bpf.h | 42 ++++++++++++++ tools/testing/selftests/bpf/progs/mptcp_subflow.c | 69 +++++++++++++++++++++++ 3 files changed, 112 insertions(+), 1 deletion(-) diff --git a/MAINTAINERS b/MAINTAINERS index 30a9b9450e11..2674b86209d1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -16058,7 +16058,7 @@ F: include/net/mptcp.h F: include/trace/events/mptcp.h F: include/uapi/linux/mptcp*.h F: net/mptcp/ -F: tools/testing/selftests/bpf/*/*mptcp*.c +F: tools/testing/selftests/bpf/*/*mptcp*.[ch] F: tools/testing/selftests/net/mptcp/ NETWORKING [TCP] diff --git a/tools/testing/selftests/bpf/progs/mptcp_bpf.h b/tools/testing/selftests/bpf/progs/mptcp_bpf.h new file mode 100644 index 000000000000..179b74c1205f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/mptcp_bpf.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __MPTCP_BPF_H__ +#define __MPTCP_BPF_H__ + +#include "bpf_experimental.h" + +/* list helpers from include/linux/list.h */ +static inline int list_is_head(const struct list_head *list, + const struct list_head *head) +{ + return list == head; +} + +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + +#define list_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + +#define list_next_entry(pos, member) \ + list_entry((pos)->member.next, typeof(*(pos)), member) + +#define list_entry_is_head(pos, head, member) \ + list_is_head(&pos->member, (head)) + +/* small difference: 'cond_break' has been added in the conditions */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_first_entry(head, typeof(*pos), member); \ + cond_break, !list_entry_is_head(pos, head, member); \ + pos = list_next_entry(pos, member)) + +/* mptcp helpers from protocol.h */ +#define mptcp_for_each_subflow(__msk, __subflow) \ + list_for_each_entry(__subflow, &((__msk)->conn_list), node) + +static __always_inline struct sock * +mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) +{ + return subflow->tcp_sock; +} + +#endif diff --git a/tools/testing/selftests/bpf/progs/mptcp_subflow.c b/tools/testing/selftests/bpf/progs/mptcp_subflow.c index 2e28f4a215b5..70302477e326 100644 --- a/tools/testing/selftests/bpf/progs/mptcp_subflow.c +++ b/tools/testing/selftests/bpf/progs/mptcp_subflow.c @@ -4,10 +4,12 @@ /* vmlinux.h, bpf_helpers.h and other 'define' */ #include "bpf_tracing_net.h" +#include "mptcp_bpf.h" char _license[] SEC("license") = "GPL"; char cc[TCP_CA_NAME_MAX] = "reno"; +int pid; /* Associate a subflow counter to each token */ struct { @@ -57,3 +59,70 @@ int mptcp_subflow(struct bpf_sock_ops *skops) return 1; } + +static int _check_getsockopt_subflow_mark(struct mptcp_sock *msk, struct bpf_sockopt *ctx) +{ + struct mptcp_subflow_context *subflow; + int i = 0; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk; + + ssk = mptcp_subflow_tcp_sock(bpf_core_cast(subflow, + struct mptcp_subflow_context)); + + if (ssk->sk_mark != ++i) { + ctx->retval = -2; + break; + } + } + + return 1; +} + +static int _check_getsockopt_subflow_cc(struct mptcp_sock *msk, struct bpf_sockopt *ctx) +{ + struct mptcp_subflow_context *subflow; + + mptcp_for_each_subflow(msk, subflow) { + struct inet_connection_sock *icsk; + struct sock *ssk; + + ssk = mptcp_subflow_tcp_sock(bpf_core_cast(subflow, + struct mptcp_subflow_context)); + icsk = bpf_core_cast(ssk, struct inet_connection_sock); + + if (ssk->sk_mark == 2 && + __builtin_memcmp(icsk->icsk_ca_ops->name, cc, TCP_CA_NAME_MAX)) { + ctx->retval = -2; + break; + } + } + + return 1; +} + +SEC("cgroup/getsockopt") +int _getsockopt_subflow(struct bpf_sockopt *ctx) +{ + struct bpf_sock *sk = ctx->sk; + struct mptcp_sock *msk; + + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 1; + + if (!sk || sk->protocol != IPPROTO_MPTCP || + (!(ctx->level == SOL_SOCKET && ctx->optname == SO_MARK) && + !(ctx->level == SOL_TCP && ctx->optname == TCP_CONGESTION))) + return 1; + + msk = bpf_core_cast(sk, struct mptcp_sock); + if (msk->pm.subflows != 1) { + ctx->retval = -1; + return 1; + } + + if (ctx->optname == SO_MARK) + return _check_getsockopt_subflow_mark(msk, ctx); + return _check_getsockopt_subflow_cc(msk, ctx); +}