From patchwork Fri May 20 01:21:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 12856175 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D8A6C433FE for ; Fri, 20 May 2022 01:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344409AbiETBVy (ORCPT ); Thu, 19 May 2022 21:21:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344414AbiETBVo (ORCPT ); Thu, 19 May 2022 21:21:44 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB8D429831 for ; Thu, 19 May 2022 18:21:43 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id d4-20020a170902c18400b001619cd42b0aso3349131pld.19 for ; Thu, 19 May 2022 18:21:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Qrx145uZheTwW5S3ogXKwTgZQSI1uZw5vSyKKikVhSA=; b=CAgIAB5LDMWdv//SxiQPXDjTJlwlbBN2rmSL+nPOHdEijE1xOdZXxikE5SFGVUzPQT kjSilKK8B+8JGiNJdgJJEQ1CXfsIqBrjW0AukAeEjIP6fvmaYKALizTzEEm9GEJdjGMh e277Rxzchd/dAtUR6iSQr+g0YeVpWZd6HO+Lqnrhii+s/ZSvwAjN+7EmQWlr+9+wg3M1 Z+4FeTeZXJ6zzpQJYpoS6/l2SeuU13lgYxw9pwqsamHmU1v+X0NPvIBBZKg/srA8xqW1 HXJudJNsY/+9ZEGpxckZsze5cBXJHIfINh7bx4uWYb3j4ghE8vYb6avCtaR6pi/MjReR bKNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Qrx145uZheTwW5S3ogXKwTgZQSI1uZw5vSyKKikVhSA=; b=6zl1hxgnnzRBNPwWKu6aJgEG7AmYVrzt8YR12pgi+Ma8pVin7JoZxEfdd20ScVwqay t+U6Q06wCeOAM3SLixgjmPS7+EHGVzzK9zyj0OEwx28ugTuo5S6pCLkyT4qgdLkDsxag fW73J1VSodfhtdpTk/JLtdLnEw8rtAmtM2Ozo8mzQ/gkZFjhi0T4lQTAEJ+vTp2z2+lj swSKJim35u8klnl7gILTmEGVi3ANiSMoUYc1gBrOdY8rujz9PyQodMJYPPPq1pY4Ax+a vQrOEFaPodlJAtpuAPl1A6ymkahFZ/HXRZN+vD4CjOqWJCaBxJ5PMU17F0kTjOfynhYv sVpw== X-Gm-Message-State: AOAM532/nJrNC8tobGklT7l38Xsv6N+dUrSxuQA2cVQP8txEmwvUn53s qCbMi0iwGqacsAVVNf8w13EvRT7FeSNVE/uV X-Google-Smtp-Source: ABdhPJxVt9kfrm7048uGAWHslUU6OTNJ04ersU8aLYVdcbVg3H9cOlpukOXF+BPyfd0JGwUqB8vULWOmNQBYFxat X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a05:6a00:1348:b0:518:6ef5:ac3 with SMTP id k8-20020a056a00134800b005186ef50ac3mr536051pfu.69.1653009703123; Thu, 19 May 2022 18:21:43 -0700 (PDT) Date: Fri, 20 May 2022 01:21:31 +0000 In-Reply-To: <20220520012133.1217211-1-yosryahmed@google.com> Message-Id: <20220520012133.1217211-4-yosryahmed@google.com> Mime-Version: 1.0 References: <20220520012133.1217211-1-yosryahmed@google.com> X-Mailer: git-send-email 2.36.1.124.g0e6072fb45-goog Subject: [PATCH bpf-next v1 3/5] bpf: Introduce cgroup iter From: Yosry Ahmed To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan , Roman Gushchin , Michal Hocko Cc: Stanislav Fomichev , David Rientjes , Greg Thelen , Shakeel Butt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, Yosry Ahmed Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Hao Luo Introduce a new type of iter prog: cgroup. Unlike other bpf_iter, this iter doesn't iterate a set of kernel objects. Instead, it is supposed to be parameterized by a cgroup id and prints only that cgroup. So one needs to specify a target cgroup id when attaching this iter. The target cgroup's state can be read out via a link of this iter. Signed-off-by: Hao Luo Signed-off-by: Yosry Ahmed --- include/linux/bpf.h | 2 + include/uapi/linux/bpf.h | 6 ++ kernel/bpf/Makefile | 3 + kernel/bpf/cgroup_iter.c | 148 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 6 ++ 5 files changed, 165 insertions(+) create mode 100644 kernel/bpf/cgroup_iter.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c107392b0ba7..74c30fe20c23 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -44,6 +44,7 @@ struct kobject; struct mem_cgroup; struct module; struct bpf_func_state; +struct cgroup; extern struct idr btf_idr; extern spinlock_t btf_idr_lock; @@ -1581,6 +1582,7 @@ int bpf_obj_get_user(const char __user *pathname, int flags); struct bpf_iter_aux_info { struct bpf_map *map; + struct cgroup *cgroup; }; typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 0210f85131b3..e5bc40d4bccc 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -91,6 +91,9 @@ union bpf_iter_link_info { struct { __u32 map_fd; } map; + struct { + __u64 cgroup_id; + } cgroup; }; /* BPF syscall commands, see bpf(2) man-page for more details. */ @@ -5965,6 +5968,9 @@ struct bpf_link_info { struct { __u32 map_id; } map; + struct { + __u64 cgroup_id; + } cgroup; }; } iter; struct { diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 057ba8e01e70..3e563b163d49 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -36,6 +36,9 @@ obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o obj-${CONFIG_BPF_LSM} += bpf_lsm.o endif obj-$(CONFIG_BPF_PRELOAD) += preload/ +ifeq ($(CONFIG_CGROUPS),y) +obj-$(CONFIG_BPF_SYSCALL) += cgroup_iter.o +endif obj-$(CONFIG_BPF_SYSCALL) += relo_core.o $(obj)/relo_core.o: $(srctree)/tools/lib/bpf/relo_core.c FORCE diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c new file mode 100644 index 000000000000..86bdfe135d24 --- /dev/null +++ b/kernel/bpf/cgroup_iter.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2022 Google */ +#include +#include +#include +#include +#include + +struct bpf_iter__cgroup { + __bpf_md_ptr(struct bpf_iter_meta *, meta); + __bpf_md_ptr(struct cgroup *, cgroup); +}; + +static void *cgroup_iter_seq_start(struct seq_file *seq, loff_t *pos) +{ + /* Only one session is supported. */ + if (*pos > 0) + return NULL; + + if (*pos == 0) + ++*pos; + + return *(struct cgroup **)seq->private; +} + +static void *cgroup_iter_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + ++*pos; + return NULL; +} + +static int cgroup_iter_seq_show(struct seq_file *seq, void *v) +{ + struct bpf_iter__cgroup ctx; + struct bpf_iter_meta meta; + struct bpf_prog *prog; + int ret = 0; + + ctx.meta = &meta; + ctx.cgroup = v; + meta.seq = seq; + prog = bpf_iter_get_info(&meta, false); + if (prog) + ret = bpf_iter_run_prog(prog, &ctx); + + return ret; +} + +static void cgroup_iter_seq_stop(struct seq_file *seq, void *v) +{ +} + +static const struct seq_operations cgroup_iter_seq_ops = { + .start = cgroup_iter_seq_start, + .next = cgroup_iter_seq_next, + .stop = cgroup_iter_seq_stop, + .show = cgroup_iter_seq_show, +}; + +BTF_ID_LIST_SINGLE(bpf_cgroup_btf_id, struct, cgroup) + +static int cgroup_iter_seq_init(void *priv_data, struct bpf_iter_aux_info *aux) +{ + *(struct cgroup **)priv_data = aux->cgroup; + return 0; +} + +static const struct bpf_iter_seq_info cgroup_iter_seq_info = { + .seq_ops = &cgroup_iter_seq_ops, + .init_seq_private = cgroup_iter_seq_init, + .seq_priv_size = sizeof(struct cgroup *), +}; + +static int bpf_iter_attach_cgroup(struct bpf_prog *prog, + union bpf_iter_link_info *linfo, + struct bpf_iter_aux_info *aux) +{ + struct cgroup *cgroup; + + cgroup = cgroup_get_from_id(linfo->cgroup.cgroup_id); + if (!cgroup) + return -EBUSY; + + aux->cgroup = cgroup; + return 0; +} + +static void bpf_iter_detach_cgroup(struct bpf_iter_aux_info *aux) +{ + if (aux->cgroup) + cgroup_put(aux->cgroup); +} + +static void bpf_iter_cgroup_show_fdinfo(const struct bpf_iter_aux_info *aux, + struct seq_file *seq) +{ + char *buf; + + seq_printf(seq, "cgroup_id:\t%llu\n", cgroup_id(aux->cgroup)); + + buf = kmalloc(PATH_MAX, GFP_KERNEL); + if (!buf) { + seq_puts(seq, "cgroup_path:\n"); + return; + } + + /* If cgroup_path_ns() fails, buf will be an empty string, cgroup_path + * will print nothing. + * + * Cgroup_path is the path in the calliing process's cgroup namespace. + */ + cgroup_path_ns(aux->cgroup, buf, sizeof(buf), + current->nsproxy->cgroup_ns); + seq_printf(seq, "cgroup_path:\t%s\n", buf); + kfree(buf); +} + +static int bpf_iter_cgroup_fill_link_info(const struct bpf_iter_aux_info *aux, + struct bpf_link_info *info) +{ + info->iter.cgroup.cgroup_id = cgroup_id(aux->cgroup); + return 0; +} + +DEFINE_BPF_ITER_FUNC(cgroup, struct bpf_iter_meta *meta, + struct cgroup *cgroup) + +static struct bpf_iter_reg bpf_cgroup_reg_info = { + .target = "cgroup", + .attach_target = bpf_iter_attach_cgroup, + .detach_target = bpf_iter_detach_cgroup, + .show_fdinfo = bpf_iter_cgroup_show_fdinfo, + .fill_link_info = bpf_iter_cgroup_fill_link_info, + .ctx_arg_info_size = 1, + .ctx_arg_info = { + { offsetof(struct bpf_iter__cgroup, cgroup), + PTR_TO_BTF_ID }, + }, + .seq_info = &cgroup_iter_seq_info, +}; + +static int __init bpf_cgroup_iter_init(void) +{ + bpf_cgroup_reg_info.ctx_arg_info[0].btf_id = bpf_cgroup_btf_id[0]; + return bpf_iter_reg_target(&bpf_cgroup_reg_info); +} + +late_initcall(bpf_cgroup_iter_init); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 0210f85131b3..e5bc40d4bccc 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -91,6 +91,9 @@ union bpf_iter_link_info { struct { __u32 map_fd; } map; + struct { + __u64 cgroup_id; + } cgroup; }; /* BPF syscall commands, see bpf(2) man-page for more details. */ @@ -5965,6 +5968,9 @@ struct bpf_link_info { struct { __u32 map_id; } map; + struct { + __u64 cgroup_id; + } cgroup; }; } iter; struct {