From patchwork Fri May 29 00:25:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 218256 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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=no 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 54CE1C433E1 for ; Fri, 29 May 2020 00:26:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26468207F9 for ; Fri, 29 May 2020 00:26:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438117AbgE2A0C (ORCPT ); Thu, 28 May 2020 20:26:02 -0400 Received: from correo.us.es ([193.147.175.20]:44218 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2438088AbgE2AZz (ORCPT ); Thu, 28 May 2020 20:25:55 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id B9F97CF67F for ; Fri, 29 May 2020 02:25:51 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id A8032DA721 for ; Fri, 29 May 2020 02:25:51 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 99EABDA715; Fri, 29 May 2020 02:25:51 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 1AB5CDA709; Fri, 29 May 2020 02:25:49 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Fri, 29 May 2020 02:25:49 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id A63EA426CCB9; Fri, 29 May 2020 02:25:48 +0200 (CEST) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, paulb@mellanox.com, ozsh@mellanox.com, vladbu@mellanox.com, jiri@resnulli.us, kuba@kernel.org, saeedm@mellanox.com, michael.chan@broadcom.com, sriharsha.basavapatna@broadcom.com Subject: [PATCH net-next 0/8] the indirect flow_block infrastructure, revisited Date: Fri, 29 May 2020 02:25:33 +0200 Message-Id: <20200529002541.19743-1-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, This series fixes b5140a36da78 ("netfilter: flowtable: add indr block setup support") that adds support for the indirect block for the flowtable. This patch crashes the kernel with the TC CT action. [ 630.908086] BUG: kernel NULL pointer dereference, address: 00000000000000f0 [ 630.908233] #PF: error_code(0x0000) - not-present page [ 630.908304] PGD 800000104addd067 P4D 800000104addd067 PUD 104311d067 PMD 0 [ 630.908380] Oops: 0000 [#1] SMP PTI [ 630.908615] RIP: 0010:nf_flow_table_indr_block_cb+0xc0/0x190 [nf_flow_table] [ 630.908690] Code: 5b 41 5c 41 5d 41 5e 41 5f 5d c3 4c 89 75 a0 4c 89 65 a8 4d 89 ee 49 89 dd 4c 89 fe 48 c7 c7 b7 64 36 a0 31 c0 e8 ce ed d8 e0 <49> 8b b7 f0 00 00 00 48 c7 c7 c8 64 36 a0 31 c0 e8 b9 ed d8 e0 49[ 630.908790] RSP: 0018:ffffc9000895f8c0 EFLAGS: 00010246 [...] [ 630.910774] Call Trace: [ 630.911192] ? mlx5e_rep_indr_setup_block+0x270/0x270 [mlx5_core] [ 630.911621] ? mlx5e_rep_indr_setup_block+0x270/0x270 [mlx5_core] [ 630.912040] ? mlx5e_rep_indr_setup_block+0x270/0x270 [mlx5_core] [ 630.912443] flow_block_cmd+0x51/0x80 [ 630.912844] __flow_indr_block_cb_register+0x26c/0x510 [ 630.913265] mlx5e_nic_rep_netdevice_event+0x9e/0x110 [mlx5_core] [ 630.913665] notifier_call_chain+0x53/0xa0 [ 630.914063] raw_notifier_call_chain+0x16/0x20 [ 630.914466] call_netdevice_notifiers_info+0x39/0x90 [ 630.914859] register_netdevice+0x484/0x550 [ 630.915256] __ip_tunnel_create+0x12b/0x1f0 [ip_tunnel] [ 630.915661] ip_tunnel_init_net+0x116/0x180 [ip_tunnel] [ 630.916062] ipgre_tap_init_net+0x22/0x30 [ip_gre] [ 630.916458] ops_init+0x44/0x110 [ 630.916851] register_pernet_operations+0x112/0x200 A workaround patch to cure this crash has been proposed. However, there is another problem: The indirect flow_block still does not work for the new TC CT action. The problem is that the existing flow_indr_block_entry callback assumes you can look up for the flowtable from the netdevice to get the flow_block. This flow_block allows you to offload the flows via TC_SETUP_CLSFLOWER. Unfortunately, it is not possible to get the flow_block from the TC CT flowtables because they are _not_ bound to any specific netdevice. = What is the indirect flow_block infrastructure? The indirect flow_block infrastructure allows drivers to offload tc/netfilter rules that belong to software tunnel netdevices, e.g. vxlan. This indirect flow_block infrastructure relates tunnel netdevices with drivers because there is no obvious way to relate these two things from the control plane. = How does the indirect flow_block work before this patchset? Front-ends register the indirect block callback through flow_indr_add_block_cb() if they support for offloading tunnel netdevices. == Setting up an indirect block 1) Drivers track tunnel netdevices via NETDEV_{REGISTER,UNREGISTER} events. If there is a new tunnel netdevice that the driver can offload, then the driver invokes __flow_indr_block_cb_register() with the new tunnel netdevice and the driver callback. The __flow_indr_block_cb_register() call iterates over the list of the front-end callbacks. 2) The front-end callback sets up the flow_block_offload structure and it invokes the driver callback to set up the flow_block. 3) The driver callback now registers the flow_block structure and it returns the flow_block back to the front-end. 4) The front-end gets the flow_block object and it is now ready to offload rules for this tunnel netdevice. A simplified callgraph is represented below. Front-end Driver NETDEV_REGISTER | __flow_indr_block_cb_register(netdev, cb_priv, driver_cb) | [1] .--------------frontend_indr_block_cb(cb_priv, driver_cb) | . setup_flow_block_offload(bo) | [2] driver_cb(bo, cb_priv) -----------. | \/ set up flow_blocks [3] | add rules to flow_block <---------- TC_SETUP_CLSFLOWER [4] == Releasing the indirect flow_block There are two possibilities, either tunnel netdevice is removed or a netdevice (port representor) is removed. === Tunnel netdevice is removed Driver waits for the NETDEV_UNREGISTER event that announces the tunnel netdevice removal. Then, it calls __flow_indr_block_cb_unregister() to remove the flow_block and rules. Callgraph is very similar to the one described above. === Netdevice is removed (port representor) Driver calls __flow_indr_block_cb_unregister() to remove the existing netfilter/tc rule that belong to the tunnel netdevice. = How does the indirect flow_block work after this patchset? Drivers register the indirect flow_block setup callback through flow_indr_dev_register() if they support for offloading tunnel netdevices. == Setting up an indirect flow_block 1) Frontends check if dev->netdev_ops->ndo_setup_tc is unset. If so, frontends call flow_indr_dev_setup_offload(). This call invokes the drivers' indirect flow_block setup callback. 2) The indirect flow_block setup callback sets up a flow_block structure which relates the tunnel netdevice and the driver. 3) The front-end uses flow_block and offload the rules. Note that the operational to set up (non-indirect) flow_block is very similar. == Releasing the indirect flow_block === Tunnel netdevice is removed This calls flow_indr_dev_setup_offload() to set down the flow_block and remove the offloaded rules. This alternate path is exercised if dev->netdev_ops->ndo_setup_tc is unset. === Netdevice is removed (port representor) If a netdevice is removed, then it might need to to clean up the offloaded tc/netfilter rules that belongs to the tunnel netdevice: 1) The driver invokes flow_indr_dev_unregister() when a netdevice is removed. 2) This call iterates over the existing indirect flow_blocks and it invokes the cleanup callback to let the front-end remove the tc/netfilter rules. The cleanup callback already provides the flow_block that the front-end needs to clean up. Front-end Driver | flow_indr_dev_unregister(...) | iterate over list of indirect flow_block and invoke cleanup callback | .----------------------------- | . frontend_flow_block_cleanup(flow_block) . | \/ remove rules to flow_block TC_SETUP_CLSFLOWER = About this patchset This patchset aims to address the existing TC CT problem while simplifying the indirect flow_block infrastructure. Saving 300 LoC in the flow_offload core and the drivers. The operational gets aligned with the (non-indirect) flow_blocks logic. Patchset is composed of: Patch #1 add nf_flow_table_gc_cleanup() which is required by the netfilter's flowtable new indirect flow_block approach. Patch #2 adds the flow_block_indr object which is actually part of of the flow_block object. This stores the indirect flow_block metadata such as the tunnel netdevice owner and the cleanup callback (in case the tunnel netdevice goes away). This patch adds flow_indr_dev_{un}register() to allow drivers to offer netdevice tunnel hardware offload to the front-ends. Then, front-ends call flow_indr_dev_setup_offload() to invoke the drivers to set up the (indirect) flow_block. Patch #3 add the tcf_block_offload_init() helper function, this is a preparation patch to adapt the tc front-end to use this new indirect flow_block infrastructure. Patch #4 updates the tc and netfilter front-ends to use the new indirect flow_block infrastructure. Patch #5 updates the mlx5 driver to use the new indirect flow_block infrastructure. Patch #6 updates the nfp driver to use the new indirect flow_block infrastructure. Patch #7 updates the bnxt driver to use the new indirect flow_block infrastructure. Patch #8 removes the indirect flow_block infrastructure version 1, now that frontends and drivers have been translated to version 2 (coming in this patchset). Please, apply. Pablo Neira Ayuso (8): netfilter: nf_flowtable: expose nf_flow_table_gc_cleanup() net: flow_offload: consolidate indirect flow_block infrastructure net: cls_api: add tcf_block_offload_init() net: use flow_indr_dev_setup_offload() mlx5: update indirect block support nfp: update indirect block support bnxt_tc: update indirect block support net: remove indirect block netdev event registration drivers/net/ethernet/broadcom/bnxt/bnxt.h | 1 - drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c | 51 +-- .../ethernet/mellanox/mlx5/core/en/rep/tc.c | 81 +---- .../ethernet/mellanox/mlx5/core/en/rep/tc.h | 4 - .../net/ethernet/mellanox/mlx5/core/en_rep.c | 1 - .../net/ethernet/mellanox/mlx5/core/en_rep.h | 5 - .../net/ethernet/netronome/nfp/flower/main.c | 11 +- .../net/ethernet/netronome/nfp/flower/main.h | 7 +- .../ethernet/netronome/nfp/flower/offload.c | 35 +- include/net/flow_offload.h | 28 +- include/net/netfilter/nf_flow_table.h | 2 + net/core/flow_offload.c | 301 +++++++----------- net/netfilter/nf_flow_table_core.c | 6 +- net/netfilter/nf_flow_table_offload.c | 85 +---- net/netfilter/nf_tables_offload.c | 69 ++-- net/sched/cls_api.c | 157 +++------ 16 files changed, 249 insertions(+), 595 deletions(-) --- 2.20.1