From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_MED,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A849C2BCA1 for ; Fri, 7 Jun 2019 16:29:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D93862064A for ; Fri, 7 Jun 2019 16:29:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cNtwItOp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730811AbfFGQ3m (ORCPT ); Fri, 7 Jun 2019 12:29:42 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:39172 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730776AbfFGQ3k (ORCPT ); Fri, 7 Jun 2019 12:29:40 -0400 Received: by mail-qt1-f201.google.com with SMTP id o16so2290190qtj.6 for ; Fri, 07 Jun 2019 09:29:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5w1rHDEgykvg+sQcOr0DvAmAd6C30bFeeDMr27zQ+cU=; b=cNtwItOpBVvg+Lrk/tY9pXQsO1xOgqYbrRVE94H6BVJD3eGMLoG09UVUPHUtPaNypN cuW3RQZZOmfDSH/u8dbHBxitIU44gXZ/u3Jwopt36zb/q9otgUH2l15NdNFxJoXNg0j8 wB9S5dyn2xXleQQIIVefiP9/pCV4vfIfKW3MVOMCsANgigh3LvV8gnELmaDA+gQuo5Wd Sn/1MUurdXd6y5A6ywPceeThVq5c/Rbhrothpo7j2uyckJv1f1PtrEc0cWCinVVQNI3/ d2ly8acJ4dXAI/BGxUEs8fRZjWV+0UWIeeSWgkjAiqfSAp9DeP9NB3vPQuy13RAKjvWN 7YnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5w1rHDEgykvg+sQcOr0DvAmAd6C30bFeeDMr27zQ+cU=; b=Oz01zU6UFlZVUV1raOsy2v/l+bMMXqRaWsvLXwGmMa62gQHtCHZACEz4JdPVjBqI3A qGAAWXT7+09StyMqYlzQh0eTyyopkUU6AHHnkwVyeXLCah5X6L//zQ9K6wL4gfLz8Qvj /+mURarnN0mG+L7ECu/k5rcC4fFQOz1BbRBOyQLaVFd0b6z2nECEvkKazKB0aem25XWJ f98Cgk2w70zao/7akhqAAqyB3QtZvoJljTc1Tdmqj6/963W6Z7x/7eZKR3TiO1LlbOSg MH2+zcxYiSFfJP0MtBBkKps+W+Pn9+XM8auYqa+dsS62W0VVkAExnfqANTcROK1ndVrG yxIA== X-Gm-Message-State: APjAAAWfxWrN3vSG9PHBdJE4kXddYPZwaDi5gDdGk8BrrJkao/PElaYD TGvqVvQNO65rSJ+WEPlAlNE70PtQ0f01jtp9w8oehbUinIgslUk3us0G3ytqhuRnesY6NyU5Tay dQ4OJih4W4ucfU6YVA/Vi4A5llfyYXB/shReq3wua2xKMTdGpvKn0nA== X-Google-Smtp-Source: APXvYqyxMA/WQRb3S3kzR7dCsZuTciJvXSDGe6u/5GqtAOZHTQAKLIZhY1wVwtt3JYYKo7FG3i1Z+9A= X-Received: by 2002:a0c:d1f0:: with SMTP id k45mr28404317qvh.69.1559924979294; Fri, 07 Jun 2019 09:29:39 -0700 (PDT) Date: Fri, 7 Jun 2019 09:29:19 -0700 In-Reply-To: <20190607162920.24546-1-sdf@google.com> Message-Id: <20190607162920.24546-8-sdf@google.com> Mime-Version: 1.0 References: <20190607162920.24546-1-sdf@google.com> X-Mailer: git-send-email 2.22.0.rc1.311.g5d7573a151-goog Subject: [PATCH bpf-next v3 7/8] bpf: add sockopt documentation From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Provide user documentation about sockopt prog type and cgroup hooks. v2: * use return code 2 for kernel bypass Signed-off-by: Stanislav Fomichev --- Documentation/bpf/index.rst | 1 + Documentation/bpf/prog_cgroup_sockopt.rst | 39 +++++++++++++++++++++++ 2 files changed, 40 insertions(+) create mode 100644 Documentation/bpf/prog_cgroup_sockopt.rst diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst index d3fe4cac0c90..801a6ed3f2e5 100644 --- a/Documentation/bpf/index.rst +++ b/Documentation/bpf/index.rst @@ -42,6 +42,7 @@ Program types .. toctree:: :maxdepth: 1 + prog_cgroup_sockopt prog_cgroup_sysctl prog_flow_dissector diff --git a/Documentation/bpf/prog_cgroup_sockopt.rst b/Documentation/bpf/prog_cgroup_sockopt.rst new file mode 100644 index 000000000000..b117451ab571 --- /dev/null +++ b/Documentation/bpf/prog_cgroup_sockopt.rst @@ -0,0 +1,39 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +BPF_PROG_TYPE_SOCKOPT +===================== + +``BPF_PROG_TYPE_SOCKOPT`` program type can be attached to two cgroup hooks: + +* ``BPF_CGROUP_GETSOCKOPT`` - called every time process executes ``getsockopt`` + system call. +* ``BPF_CGROUP_SETSOCKOPT`` - called every time process executes ``setsockopt`` + system call. + +The context (``struct bpf_sockopt``) has associated socket (``sk``) and +all input arguments: ``level``, ``optname``, ``optval`` and ``optlen``. + +BPF_CGROUP_SETSOCKOPT +===================== + +``BPF_CGROUP_SETSOCKOPT`` has a read-only context and this hook has +access to cgroup and socket local storage. + +BPF_CGROUP_GETSOCKOPT +===================== + +``BPF_CGROUP_GETSOCKOPT`` has to fill in ``optval`` and adjust +``optlen`` accordingly. Input ``optlen`` contains the maximum length +of data that can be returned to the userspace. In other words, BPF +program can't increase ``optlen``, it can only decrease it. + +Return Type +=========== + +* ``0`` - reject the syscall, ``EPERM`` will be returned to the userspace. +* ``1`` - success: after returning from the BPF hook, kernel will also + handle this socket option. +* ``2`` - success: after returning from the BPF hook, kernel will _not_ + handle this socket option; control will be returned to the userspace + instead. -- 2.22.0.rc1.311.g5d7573a151-goog