From patchwork Thu Sep 12 09:25:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geliang Tang X-Patchwork-Id: 13801794 X-Patchwork-Delegate: kuba@kernel.org 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 32EF018A6A9; Thu, 12 Sep 2024 09:26:03 +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=1726133164; cv=none; b=iqJ1eK1LInp4eogyzE8MWcTIJ0r/COTlok5s/rjLYX/ka50Cq/QJrN99yL4iMUUpPl6PSlx+rai/NRT4+tptTqt+7GVcHD4Cdggw9VEJLOg+H30u5tmvR2iEO2UMBNUfRZBFiHr57v78DHfPX1ku5wYvsnPw6ZBGSuEWILYTtcs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726133164; c=relaxed/simple; bh=i1tfent+G9wgkD21AvmV+FJAVzh/MdSal+bBN4pXdGk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mPjCMG+BQeii/8bju2rl2Hce1iF4ZcF/TPsKDUEMhpl6sGLwsoD8DK96MCV3zl/sH7dPL/tqv1Pp0bSGhLwPj9S8Bvsp1s+qgo6ak24/Eoj3wwNVfcC5CkxcNwXZx/w2euB5JMc+juHaLFiv1jYTiPl8ycQY6cNw3TaSQCYyRK8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rPV1pqjT; 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="rPV1pqjT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED118C4CEC3; Thu, 12 Sep 2024 09:26:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726133163; bh=i1tfent+G9wgkD21AvmV+FJAVzh/MdSal+bBN4pXdGk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rPV1pqjTewkJFVGHmrLq9GncYKsYuqMveK6e2e8ck6cQjPIZB8vt74UfDmphAIVKQ xOqavZ6qP3UAr62m1gMA2t18BdQZDowQsU5sfoj/AFlPh1yf5sedsH3SwAEijw5791 l6OoXK6b2Ory9fmJyQqT3bhrgLrWaRfTsrSQ9WNnGHuGRAfQvC/MV+qIftRP0dq0Y+ QfAaz4aM5Bpni1q2exFFemyxMTu22BYW/ZAudbqpyJ8/2UM4LciGdx06tcdFhaRVVT 7gB7AHnxnGltox7CoKpjJ8FB/4z8TU9QqCQr0aXKfEiJQxxYUxxlY4aemgz+JPOo7f 1upNSaLR8gcAA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang , bpf@vger.kernel.org, Martin KaFai Lau Subject: [PATCH mptcp-next v5 1/5] bpf: Add mptcp_subflow bpf_iter Date: Thu, 12 Sep 2024 17:25:51 +0800 Message-ID: <5e5b91efc6e06a90fb4d2440ddcbe9b55ee464be.1726132802.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Geliang Tang It's necessary to traverse all subflows on the conn_list of an MPTCP socket and then call kfunc to modify the fields of each subflow. In kernel space, mptcp_for_each_subflow() helper is used for this: mptcp_for_each_subflow(msk, subflow) kfunc(subflow); But in the MPTCP BPF program, this has not yet been implemented. As Martin suggested recently, this conn_list walking + modify-by-kfunc usage fits the bpf_iter use case. So this patch adds a new bpf_iter type named "mptcp_subflow" to do this and implements its helpers bpf_iter_mptcp_subflow_new()/_next()/_destroy(). Since these bpf_iter mptcp_subflow helpers are invoked in its selftest in a ftrace hook for mptcp_sched_get_send(), it's necessary to register them into a BPF_PROG_TYPE_TRACING type kfunc set together with other two used kfuncs mptcp_subflow_active() and mptcp_subflow_set_scheduled(). Then bpf_for_each() for mptcp_subflow can be used in BPF program like this: i = 0; bpf_rcu_read_lock(); bpf_for_each(mptcp_subflow, subflow, msk) { if (i++ >= MPTCP_SUBFLOWS_MAX) break; kfunc(subflow); } bpf_rcu_read_unlock(); v2: remove msk->pm.lock in _new() and _destroy() (Martin) drop DEFINE_BPF_ITER_FUNC, change opaque[3] to opaque[2] (Andrii) v3: drop bpf_iter__mptcp_subflow v4: if msk is NULL, initialize kit->msk to NULL in _new() and check it in _next() (Andrii) Suggested-by: Martin KaFai Lau Signed-off-by: Geliang Tang --- net/mptcp/bpf.c | 57 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 52 insertions(+), 5 deletions(-) diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c index 6414824402e6..fec18e7e5e4a 100644 --- a/net/mptcp/bpf.c +++ b/net/mptcp/bpf.c @@ -201,9 +201,51 @@ static const struct btf_kfunc_id_set bpf_mptcp_fmodret_set = { .set = &bpf_mptcp_fmodret_ids, }; -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "kfuncs which will be used in BPF programs"); +struct bpf_iter_mptcp_subflow { + __u64 __opaque[2]; +} __attribute__((aligned(8))); + +struct bpf_iter_mptcp_subflow_kern { + struct mptcp_sock *msk; + struct list_head *pos; +} __attribute__((aligned(8))); + +__bpf_kfunc_start_defs(); + +__bpf_kfunc int bpf_iter_mptcp_subflow_new(struct bpf_iter_mptcp_subflow *it, + struct mptcp_sock *msk) +{ + struct bpf_iter_mptcp_subflow_kern *kit = (void *)it; + + kit->msk = msk; + if (!msk) + return -EINVAL; + + kit->pos = &msk->conn_list; + return 0; +} + +__bpf_kfunc struct mptcp_subflow_context * +bpf_iter_mptcp_subflow_next(struct bpf_iter_mptcp_subflow *it) +{ + struct bpf_iter_mptcp_subflow_kern *kit = (void *)it; + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = kit->msk; + + if (!msk) + return NULL; + + subflow = list_entry(kit->pos->next, struct mptcp_subflow_context, node); + if (!subflow || list_entry_is_head(subflow, &msk->conn_list, node)) + return NULL; + + kit->pos = &subflow->node; + return subflow; +} + +__bpf_kfunc void bpf_iter_mptcp_subflow_destroy(struct bpf_iter_mptcp_subflow *it) +{ +} __bpf_kfunc struct mptcp_subflow_context * bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, unsigned int pos) @@ -218,12 +260,15 @@ __bpf_kfunc bool bpf_mptcp_subflow_queues_empty(struct sock *sk) return tcp_rtx_queue_empty(sk); } -__diag_pop(); +__bpf_kfunc_end_defs(); BTF_KFUNCS_START(bpf_mptcp_sched_kfunc_ids) +BTF_ID_FLAGS(func, bpf_iter_mptcp_subflow_new) +BTF_ID_FLAGS(func, bpf_iter_mptcp_subflow_next) +BTF_ID_FLAGS(func, bpf_iter_mptcp_subflow_destroy) +BTF_ID_FLAGS(func, mptcp_subflow_active) BTF_ID_FLAGS(func, mptcp_subflow_set_scheduled) BTF_ID_FLAGS(func, bpf_mptcp_subflow_ctx_by_pos) -BTF_ID_FLAGS(func, mptcp_subflow_active) BTF_ID_FLAGS(func, mptcp_set_timeout) BTF_ID_FLAGS(func, mptcp_wnd_end) BTF_ID_FLAGS(func, tcp_stream_memory_free) @@ -241,6 +286,8 @@ static int __init bpf_mptcp_kfunc_init(void) int ret; ret = register_btf_fmodret_id_set(&bpf_mptcp_fmodret_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, + &bpf_mptcp_sched_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_mptcp_sched_kfunc_set); #ifdef CONFIG_BPF_JIT