From patchwork Tue Aug 13 07:53:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ido Schimmel X-Patchwork-Id: 1146079 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=idosch.org Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=messagingengine.com header.i=@messagingengine.com header.b="MOBYzh7Z"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4674lZ3zR5z9sNm for ; Tue, 13 Aug 2019 17:55:54 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727892AbfHMHzv (ORCPT ); Tue, 13 Aug 2019 03:55:51 -0400 Received: from new2-smtp.messagingengine.com ([66.111.4.224]:50309 "EHLO new2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727501AbfHMHzu (ORCPT ); Tue, 13 Aug 2019 03:55:50 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailnew.nyi.internal (Postfix) with ESMTP id CFA1330F9; Tue, 13 Aug 2019 03:55:46 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Tue, 13 Aug 2019 03:55:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :message-id:mime-version:subject:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=/XkXc9khw2AEUQZdt HeCu7zEoJKyEzfX2XRGgWizNj0=; b=MOBYzh7Z+PDA0TBLVOiCeJL3emxCP377I mbC5+LDK5wgX1ohMD1yodVgupiFWLZutqF6a07G2X6OS+piC/fgWGAVKFq4+khqi +WluXdxFBQqEuUk1AjpHQkkSMBU6jnGf9aAh+kfhD8TN5meyG9G6BkqeDv3Bi+Pb 7U+qgLaJ7thlQZQqxgks9YeNuXdU/TqdqHIltTHhkKVdlGApj6VVtrnUl7T64Ur3 qjTZ25YWvliwmobcF0ArkXSXhWeWhqUG6SeWHVVF77Q5G3CSwJOf7Q2MSMi0dxy0 ap50xtAx5No6QMmyUbVLGXl1k6sJuJyhobmpVK2KRIjc66wgEf2Wg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddruddvhedguddvhecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffoggfgsedtkeertd ertddtnecuhfhrohhmpefkughoucfutghhihhmmhgvlhcuoehiughoshgthhesihguohhs tghhrdhorhhgqeenucfkphepudelfedrgeejrdduieehrddvhedunecurfgrrhgrmhepmh grihhlfhhrohhmpehiughoshgthhesihguohhstghhrdhorhhgnecuvehluhhsthgvrhfu ihiivgeptd X-ME-Proxy: Received: from splinter.mtl.com (unknown [193.47.165.251]) by mail.messagingengine.com (Postfix) with ESMTPA id E2DF080059; Tue, 13 Aug 2019 03:55:39 -0400 (EDT) From: Ido Schimmel To: netdev@vger.kernel.org Cc: davem@davemloft.net, nhorman@tuxdriver.com, jiri@mellanox.com, toke@redhat.com, dsahern@gmail.com, roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com, jakub.kicinski@netronome.com, andy@greyhouse.net, f.fainelli@gmail.com, andrew@lunn.ch, vivien.didelot@gmail.com, mlxsw@mellanox.com, Ido Schimmel Subject: [PATCH net-next v2 00/14] Add drop monitor for offloaded data paths Date: Tue, 13 Aug 2019 10:53:46 +0300 Message-Id: <20190813075400.11841-1-idosch@idosch.org> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ido Schimmel Users have several ways to debug the kernel and understand why a packet was dropped. For example, using drop monitor and perf. Both utilities trace kfree_skb(), which is the function called when a packet is freed as part of a failure. The information provided by these tools is invaluable when trying to understand the cause of a packet loss. In recent years, large portions of the kernel data path were offloaded to capable devices. Today, it is possible to perform L2 and L3 forwarding in hardware, as well as tunneling (IP-in-IP and VXLAN). Different TC classifiers and actions are also offloaded to capable devices, at both ingress and egress. However, when the data path is offloaded it is not possible to achieve the same level of introspection since packets are dropped by the underlying device and never reach the kernel. This patchset aims to solve this by allowing users to monitor packets that the underlying device decided to drop along with relevant metadata such as the drop reason and ingress port. The above is achieved by exposing a fundamental capability of devices capable of data path offloading - packet trapping. In much the same way as drop monitor registers its probe function with the kfree_skb() tracepoint, the device is instructed to pass to the CPU (trap) packets that it decided to drop in various places in the pipeline. The configuration of the device to pass such packets to the CPU is performed using devlink, as it is not specific to a port, but rather to a device. In the future, we plan to control the policing of such packets using devlink, in order not to overwhelm the CPU. While devlink is used as the control path, the dropped packets are passed along with metadata to drop monitor, which reports them to userspace as netlink events. This allows users to use the same interface for the monitoring of both software and hardware drops. Logically, the solution looks as follows: Netlink event: Packet w/ metadata Or a summary of recent drops ^ | Userspace | +---------------------------------------------------+ Kernel | | +-------+--------+ | | | drop_monitor | | | +-------^--------+ | | | +----+----+ | | Kernel's Rx path | devlink | (non-drop traps) | | +----^----+ ^ | | +-----------+ | +-------+-------+ | | | Device driver | | | +-------^-------+ Kernel | +---------------------------------------------------+ Hardware | | Trapped packet | +--+---+ | | | ASIC | | | +------+ In order to reduce the patch count, this patchset only includes integration with netdevsim. A follow-up patchset will add devlink-trap support in mlxsw. Patches #1-#7 extend drop monitor to also monitor hardware originated drops. Patches #8-#10 add the devlink-trap infrastructure. Patches #11-#12 add devlink-trap support in netdevsim. Patches #13-#14 add tests for the generic infrastructure over netdevsim. Example ======= Instantiate netdevsim --------------------- # echo "10 1" > /sys/bus/netdevsim/new_device # ip link set dev eth0 up List supported traps -------------------- # devlink trap show netdevsim/netdevsim10: name source_mac_is_multicast type drop generic true action drop group l2_drops name vlan_tag_mismatch type drop generic true action drop group l2_drops name ingress_vlan_filter type drop generic true action drop group l2_drops name ingress_spanning_tree_filter type drop generic true action drop group l2_drops name port_list_is_empty type drop generic true action drop group l2_drops name port_loopback_filter type drop generic true action drop group l2_drops name fid_miss type exception generic false action trap group l2_drops name blackhole_route type drop generic true action drop group l3_drops name ttl_value_is_too_small type exception generic true action trap group l3_drops name tail_drop type drop generic true action drop group buffer_drops Enable a trap ------------- # devlink trap set netdevsim/netdevsim10 trap blackhole_route action trap Query statistics ---------------- # devlink -s trap show netdevsim/netdevsim10 trap blackhole_route netdevsim/netdevsim10: name blackhole_route type drop generic true action trap group l3_drops stats: rx: bytes 7384 packets 52 Monitor dropped packets ----------------------- dropwatch> set alertmode packet Setting alert mode Alert mode successfully set dropwatch> set sw true setting software drops monitoring to 1 dropwatch> set hw true setting hardware drops monitoring to 1 dropwatch> start Enabling monitoring... Kernel monitoring activated. Issue Ctrl-C to stop monitoring drop at: ttl_value_is_too_small (l3_drops) origin: hardware input port ifindex: 55 input port name: eth0 timestamp: Mon Aug 12 10:52:20 2019 445911505 nsec protocol: 0x800 length: 142 original length: 142 drop at: ip6_mc_input+0x8b8/0xef8 (0xffffffff9e2bb0e8) origin: software input port ifindex: 4 timestamp: Mon Aug 12 10:53:37 2019 024444587 nsec protocol: 0x86dd length: 110 original length: 110 Future plans ============ * Provide more drop reasons as well as more metadata * Add dropmon support to libpcap, so that tcpdump/tshark could specifically listen on dropmon traffic, instead of capturing all netlink packets via nlmon interface Changes in v2: * Use drop monitor to report dropped packets instead of devlink * Add drop monitor patches * Add test cases Ido Schimmel (14): drop_monitor: Move per-CPU data init/fini to separate functions drop_monitor: Initialize hardware per-CPU data drop_monitor: Add basic infrastructure for hardware drops drop_monitor: Consider all monitoring states before performing configuration drop_monitor: Add support for packet alert mode for hardware drops drop_monitor: Add support for summary alert mode for hardware drops drop_monitor: Allow user to start monitoring hardware drops devlink: Add packet trap infrastructure devlink: Add generic packet traps and groups Documentation: Add devlink-trap documentation netdevsim: Add devlink-trap support Documentation: Add description of netdevsim traps selftests: devlink_trap: Add test cases for devlink-trap Documentation: Add a section for devlink-trap testing .../networking/devlink-trap-netdevsim.rst | 20 + Documentation/networking/devlink-trap.rst | 207 ++++ Documentation/networking/index.rst | 2 + MAINTAINERS | 1 + drivers/net/netdevsim/dev.c | 281 ++++- drivers/net/netdevsim/netdevsim.h | 1 + include/net/devlink.h | 175 +++ include/net/drop_monitor.h | 33 + include/uapi/linux/devlink.h | 62 + include/uapi/linux/net_dropmon.h | 15 + net/Kconfig | 1 + net/core/devlink.c | 1080 ++++++++++++++++- net/core/drop_monitor.c | 724 ++++++++++- tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/config | 1 + tools/testing/selftests/net/devlink_trap.sh | 616 ++++++++++ 16 files changed, 3191 insertions(+), 30 deletions(-) create mode 100644 Documentation/networking/devlink-trap-netdevsim.rst create mode 100644 Documentation/networking/devlink-trap.rst create mode 100644 include/net/drop_monitor.h create mode 100755 tools/testing/selftests/net/devlink_trap.sh