From patchwork Wed Nov 9 12:54:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Romanovsky X-Patchwork-Id: 13037512 X-Patchwork-Delegate: kuba@kernel.org 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 128F8C4332F for ; Wed, 9 Nov 2022 12:55:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229814AbiKIMz1 (ORCPT ); Wed, 9 Nov 2022 07:55:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbiKIMzK (ORCPT ); Wed, 9 Nov 2022 07:55:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92EB818E02 for ; Wed, 9 Nov 2022 04:55:08 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 329C861A87 for ; Wed, 9 Nov 2022 12:55:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28C16C433D7; Wed, 9 Nov 2022 12:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667998507; bh=oKEHuUbJL9Qe0CsyOVav/UpxmVArOGsjLdUc2XAWs+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rPVGihCCPX2BgxX7igu2qaV9vA5qz1hpsDvgYjNwf2v990V95SCZttW+zgKgOTK/l 7CfJFkMecCozeMphzrwhKuRxMJbLuyMb4dB3Ipt7nW/2LT7IFK7qtYzkH191EGMuw4 CF+hFqFlyVNNj8OQGoIWKw5sgKM3xLZxZ6P+84mQWARt09VMUh+vFJyIEOHLW7L5hH rEKFc3eD850PnxhQmZYBzttX6aPjl12oAhyQ7zQBXZgds59HwGIzX6Vd7zG+CHIFGE 5fFwzWL2JGom7ZI9XphikbUwqZEqvYsX22GM30MC1/+TDlxr+lxCInhEcTrYDy8S1p SPzSWVIZyq0VQ== From: Leon Romanovsky To: Steffen Klassert Cc: Leon Romanovsky , "David S. Miller" , Eric Dumazet , Herbert Xu , Jakub Kicinski , netdev@vger.kernel.org Subject: [PATCH xfrm-next v7 8/8] xfrm: document IPsec packet offload mode Date: Wed, 9 Nov 2022 14:54:36 +0200 Message-Id: <582d8f57e2faa56ba06ff24701413aa8c397be06.1667997522.git.leonro@nvidia.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Leon Romanovsky Extend XFRM device offload API description with newly added packet offload mode. Signed-off-by: Leon Romanovsky --- Documentation/networking/xfrm_device.rst | 62 ++++++++++++++++++++---- 1 file changed, 53 insertions(+), 9 deletions(-) diff --git a/Documentation/networking/xfrm_device.rst b/Documentation/networking/xfrm_device.rst index 01391dfd37d9..40ea565812f6 100644 --- a/Documentation/networking/xfrm_device.rst +++ b/Documentation/networking/xfrm_device.rst @@ -5,6 +5,7 @@ XFRM device - offloading the IPsec computations =============================================== Shannon Nelson +Leon Romanovsky Overview @@ -18,10 +19,21 @@ can radically increase throughput and decrease CPU utilization. The XFRM Device interface allows NIC drivers to offer to the stack access to the hardware offload. +Right now, there are two types of hardware offload that kernel supports. + * IPsec crypto offload: + * NIC performs encrypt/decrypt + * Kernel does everything else + * IPsec packet offload: + * NIC performs encrypt/decrypt + * NIC does encapsulation + * Kernel and NIC have SA and policy in-sync + * NIC handles the SA and policies states + * The Kernel talks to the keymanager + Userland access to the offload is typically through a system such as libreswan or KAME/raccoon, but the iproute2 'ip xfrm' command set can be handy when experimenting. An example command might look something -like this:: +like this for crypto offload: ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \ reqid 0x07 replay-window 32 \ @@ -29,6 +41,17 @@ like this:: sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \ offload dev eth4 dir in +and for packetoffload + + ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \ + reqid 0x07 replay-window 32 \ + aead 'rfc4106(gcm(aes))' 0x44434241343332312423222114131211f4f3f2f1 128 \ + sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \ + offload packet dev eth4 dir in + + ip x p add src 14.0.0.70 dst 14.0.0.52 offload packet dev eth4 dir in + tmpl src 14.0.0.70 dst 14.0.0.52 proto esp reqid 10000 mode transport + Yes, that's ugly, but that's what shell scripts and/or libreswan are for. @@ -40,17 +63,24 @@ Callbacks to implement /* from include/linux/netdevice.h */ struct xfrmdev_ops { + /* Crypto and Full offload callbacks */ int (*xdo_dev_state_add) (struct xfrm_state *x); void (*xdo_dev_state_delete) (struct xfrm_state *x); void (*xdo_dev_state_free) (struct xfrm_state *x); bool (*xdo_dev_offload_ok) (struct sk_buff *skb, struct xfrm_state *x); void (*xdo_dev_state_advance_esn) (struct xfrm_state *x); + + /* Solely packet offload callbacks */ + void (*xdo_dev_state_update_curlft) (struct xfrm_state *x); + int (*xdo_dev_policy_add) (struct xfrm_policy *x); + void (*xdo_dev_policy_delete) (struct xfrm_policy *x); + void (*xdo_dev_policy_free) (struct xfrm_policy *x); }; -The NIC driver offering ipsec offload will need to implement these -callbacks to make the offload available to the network stack's -XFRM subsystem. Additionally, the feature bits NETIF_F_HW_ESP and +The NIC driver offering ipsec offload will need to implement callbacks +relevant to supported offload to make the offload available to the network +stack's XFRM subsystem. Additionally, the feature bits NETIF_F_HW_ESP and NETIF_F_HW_ESP_TX_CSUM will signal the availability of the offload. @@ -79,7 +109,8 @@ and an indication of whether it is for Rx or Tx. The driver should =========== =================================== 0 success - -EOPNETSUPP offload not supported, try SW IPsec + -EOPNETSUPP offload not supported, try SW IPsec, + not applicable for packet offload mode other fail the request =========== =================================== @@ -96,6 +127,7 @@ will serviceable. This can check the packet information to be sure the offload can be supported (e.g. IPv4 or IPv6, no IPv4 options, etc) and return true of false to signify its support. +Crypto offload mode: When ready to send, the driver needs to inspect the Tx packet for the offload information, including the opaque context, and set up the packet send accordingly:: @@ -139,13 +171,25 @@ the stack in xfrm_input(). In ESN mode, xdo_dev_state_advance_esn() is called from xfrm_replay_advance_esn(). Driver will check packet seq number and update HW ESN state machine if needed. +Full offload mode: +HW adds and deletes XFRM headers. So in RX path, XFRM stack is bypassed if HW +reported success. In TX path, the packet lefts kernel without extra header +and not encrypted, the HW is responsible to perform it. + When the SA is removed by the user, the driver's xdo_dev_state_delete() -is asked to disable the offload. Later, xdo_dev_state_free() is called -from a garbage collection routine after all reference counts to the state +and xdo_dev_policy_delete() are asked to disable the offload. Later, +xdo_dev_state_free() and xdo_dev_policy_free() are called from a garbage +collection routine after all reference counts to the state and policy have been removed and any remaining resources can be cleared for the offload state. How these are used by the driver will depend on specific hardware needs. As a netdev is set to DOWN the XFRM stack's netdev listener will call -xdo_dev_state_delete() and xdo_dev_state_free() on any remaining offloaded -states. +xdo_dev_state_delete(), xdo_dev_policy_delete(), xdo_dev_state_free() and +xdo_dev_policy_free() on any remaining offloaded states. + +Outcome of HW handling packets, the XFRM core can't count hard, soft limits. +The HW/driver are responsible to perform it and provide accurate data when +xdo_dev_state_update_curlft() is called. In case of one of these limits +occuried, the driver needs to call to xfrm_state_check_expire() to make sure +that XFRM performs rekeying sequence.