From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SA9PR02CU001.outbound.protection.outlook.com (mail-southcentralusazon11013015.outbound.protection.outlook.com [40.93.196.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA8993FA5D4; Thu, 27 Aug 2026 09:05:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.196.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787821547; cv=fail; b=ZNMLHgGgdnJpczE/uHIvba7usA2nKSAfbjxhIjLBzb59912IPvgUfv195yQgV866NP5IX+QoR7wWfOhpiOx1HMRseNnHuqL0dndQNuOogVFrvVdZdI6s/VSBKjstw1Scm7ha10NMx9b1EFizagQxTZkucVodTgdPSCbrX9pOqpA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787821547; c=relaxed/simple; bh=w1Ls+fOmMbVNhGJUFmRyfm3mMbeeyZ0a7+KTnSiIORU=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=OGeOThU6x7W85nhlFESjr57U/nu8VgrKpAdIl6Ld6KieH2sv0/Ldte2AKqXu7fqIiDrDrtOrGVXYwYPH61XZ07XyQy6Vj7VPWhfzQKd/Ljjh+z1aede4qhJpCzodEUlmo4ZsiathMV2RvrqZDuDBPG9EicgE9TIB2nQc61JZsfw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=dtCsUdoT; arc=fail smtp.client-ip=40.93.196.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="dtCsUdoT" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=pK/SVmZgL08KcVkUQSl34E+g4ehfEG0I5WK+8RkCCXYmW/UYTPbGFemSWtK0VVlPiDiAext/IMYJc3wwrguKuhUKFK8CoeWQn6cR1L9xNC8qgahttnvM4DgXUCyJjiXI+UJt7GgN2RhDDp3PGccdyqBecb/NEQv+kwhdjvsXZ5/26I4/oBxgAEMSRpAKs0V3TtC+XqYPy/VKVb/HC+TKReR02WHtAWCZHMikHTs8mXwnf8lO/VusWBk7oTK9J7SubyK8Hw7pIskQMnNW9ZyRM/HC2WN6CjmjQwYtiZch7m8W/P2uiMz+T1WzCgtPfDWx8t5xqYe3P/NG03RjSn1kFA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=x49BluRE+DKMwsyx4GTxYWwJYuy9ssb22kTYWDPOEic=; b=qjGHWjswl7fVA94am+l+y/H6Cig/wYFZ4Xy1WqJ+Gsc+x/x/TgPtwdo10Z28YoSIUSt5zLFO0cTv0qmGso7gmoIgodUM34hFnVJyf3JJufVhVlJk996xvFPDOcggGHBkhRky+FEJhSNVcuvaTvzBf+Oiu8QH7d1MKa1j2vxjLU9D4B4f/AtF0w2Mo1XJybf3tNW1aVQ3lruj8lBas3CpchBt3TjXG5ZI2Bnt2pLBOR0lypNb+U9DMjzSTr8T/pIv/j+Ay9aEBAL97E2JyyjZ9L04IFvEP7xSVh4+/N3bljtp3uXmEtCFnBd9XOJUY2wEYZFFnEFJ7qtyVACgFFew6w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=x49BluRE+DKMwsyx4GTxYWwJYuy9ssb22kTYWDPOEic=; b=dtCsUdoTOBwMAk75LAJNnpPcpAPz4tl7N4jA9A+g5/viRO1Lo+mnjdH/S6NhIZAqIh1dvAfbxwnnkJvNtviWYbssxN28ZPaU2GDANHgXH/Z+tHCBVQpdq/TF+/zEPy3fYQkRsu4udB0Cn1OiVKKWdH9dHxJLTvHcrC5CMdjPqw9BfN913wE2Ps3jU0NTcWKTXZQJUeaFaCzdK0eBfzG6z/JB9/peSozOM+OsnAR3hyNQT6nxga5ByfIMOLkr9htPgzzjT1+kDirUbM1LPW23zp/daTtEKe5On/oNjuZ4AkpuRkdfpfHqL7RT/Hj137V84NjZiwvBAEyA7tkk8U2jwA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) by PH0PR12MB7792.namprd12.prod.outlook.com (2603:10b6:510:281::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.10; Thu, 27 Aug 2026 09:05:31 +0000 Received: from PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499]) by PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499%3]) with mapi id 15.21.0360.008; Thu, 27 Aug 2026 09:05:25 +0000 Date: Thu, 27 Aug 2026 12:05:16 +0300 From: Ido Schimmel To: Lawrence Lee Cc: David Ahern , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Arun Ajith S , Roopa Prabhu , Jaehee Park , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC net-next] ipv6: update NUD_FAILED neighbors from NA messages Message-ID: <20260827090516.GA2014023@shredder> References: <20260813233344.445265-1-lfqlee314@gmail.com> <20260825115226.GA1338930@shredder> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: TL2P290CA0030.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:3::16) To PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB7957:EE_|PH0PR12MB7792:EE_ X-MS-Office365-Filtering-Correlation-Id: 7db0af26-2f69-40c5-94b8-08df041a5517 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|23010399003|366016|6133799003|10067099003|56012099006|11063799006|4143699003|18002099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR12MB7957.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(23010399003)(366016)(6133799003)(10067099003)(56012099006)(11063799006)(4143699003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?OzvEAo6eccA1wn+rucmmPjlIgYq2iZLQEQoTZW/dc3PH1d7+BNnJEABJfg1t?= =?us-ascii?Q?duo2QddlfgX2XrKtvRysb2XhB9hr8faXD7RNdbC9xVYOskBUJzqeyRdWyJZl?= =?us-ascii?Q?Jap3hRAmEhvoLV6wI7BvNJmEAgQoYm1eeh9OWoEM5wpQao/EKU8RX/lC+al/?= =?us-ascii?Q?JMP2AmPSXw2c60v7SJO3lqcBvrUd3lSwgRI4mLY4V0AALVQ9NPHoq9pJ9JUK?= =?us-ascii?Q?bOcjHuiUoaIgNUkO7Vsid/Twf+eRwK7xmIvCs1c/bErQdNuEGVIoZET0M2Mq?= =?us-ascii?Q?5pBp88UFf4V0i5Zk7IUZ6nbv1Icdq3zNibjQipKv0EQCp8qgy1PNELGn53M9?= =?us-ascii?Q?bZNKRKq1ru45z2qOcq/+A8crLrfOLiWnL0BXK9s6CI7ZlzxDy4AYgTNmy2nO?= =?us-ascii?Q?q2dwXJze83IV1wlBcoRsh37aAqzUXNvLLqK6muDUkoAcqOekPwzPWGCmKt6A?= =?us-ascii?Q?FtRkpKhy+b6bthWAhfopX2tcmLUMW0u9q33YzZatYD0dsJXo2n9/EK5EUPGL?= =?us-ascii?Q?+zfCqEbii0MyidjANUjQXzytt72YvUJb6FqDUGC+1WxstAu5oCa4AuLbemV9?= =?us-ascii?Q?IDzr+ciLIQqt2csm+zHsgUIFQyIYQiILhYwcpnpVN7dDZM/G3Sz+bQyxS7xY?= =?us-ascii?Q?Pw9CmLJf1/29d72tIqOwEPUjn+3m4ZGuSLQ23t1/JrqzrheGa+H4Vb3GwN7Q?= =?us-ascii?Q?VAMLepL/UyGdOfB6gIgv31ehrc/PafyslQQEolSfDxE8C1qI2/qlN3CuSlP6?= =?us-ascii?Q?R6qdd4E6L2o0phzMLXaCc3bYjlJko1uLe1hRmR3vX8b4cXzhKgiBaxx/1GFM?= =?us-ascii?Q?hiSA883G4TPw1zQSubEjg+N40nYNCRPNfdVk5K6cC4beHCv5pDKVVBUuZk4l?= =?us-ascii?Q?w5nejIjSHXEFZQ2KQwP+q+/lQZZfwiVeXXMy1+i/kPpuA4sDrgxo9vnIljwY?= =?us-ascii?Q?bGUxBD/89fr3ESKOeZ3SUDqFUGQQjlfFi0YgQPithCGI9lHKk04IZEjndYhI?= =?us-ascii?Q?CTT6r2Uw4Fg1zj5KsiAJeiHoGNyixCdmRSuIOZqTrYQD7TijuVCkBQzzEJ4D?= =?us-ascii?Q?g3zjF2fjABRGbZchKtcxSOcet/PTwP2qJ67ar8Lo/0monjE+LLglKNxZPeHR?= =?us-ascii?Q?S/CdTM7tl3Fhb+gvNf+UPuEocl4RM+48MaIAm2wiocUkw5UZRD7Yi/6dNb+R?= =?us-ascii?Q?necyaYdgBdkMSHVkR8lPwTgJejC8JDT5CKq/Z6nNS1w7Aquz591d9c17bWT4?= =?us-ascii?Q?VR0kj0+vbiDwkn2ndLnUUkaMdTpKML2n4RPCWhVtDPSXeJtuZTEAW4SNzdn9?= =?us-ascii?Q?kgITMk2TuqiLuBRQBuuvfmO5qi/yXp7MeOl9eprcaaWrEX3dZlNeYJOeNst7?= =?us-ascii?Q?uA5mGoutcf8B9+hK/heNuOtK5pUMJb34t3hAndbvJElzEh99bY0JLXtWKeb/?= =?us-ascii?Q?Tzsxgv1jS6ZQyau9H6CmPgx+kjwiS8bD7P0Jav9HwZ3bwRv086Yaged+o65E?= =?us-ascii?Q?DNGjXyF6HIxdvKem8iSgOtOiZuO+lrxt9wMkESDE9tMitEa7nCvHiSAiQpAP?= =?us-ascii?Q?m67nbZfdqqA5MZ+TeQ9nJgQQpDI49Y2HVLS1j2KFJmXsebZwNu/JiafeHFtD?= =?us-ascii?Q?NQSytcKElYbZmbEocspgAFpTkF1qqJyhTZtG1YWiFhvx8ZS8LHRyYX/QiQS3?= =?us-ascii?Q?IT7IdFvLGuKLrSMdFidVr4IAWcE/gMPh+0npqcPy5SFfbhJwpnHCQuUJ3BCS?= =?us-ascii?Q?mPxlK2QE2A=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7db0af26-2f69-40c5-94b8-08df041a5517 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB7957.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Aug 2026 09:05:25.8949 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 8vQnfM7PsSDyvmoRQWV3u9ImCWJL0lLxgAJxV1qoLgb7Q1E4+KbiQq75ucJdruO3+buaEd61EIEcAwivMRJDBA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB7792 On Tue, Aug 25, 2026 at 06:07:44PM +0000, Lawrence Lee wrote: > Sorry I should have been more specific before. Maybe a better way to > phrase it is that this would be analogous to IPv4 in the sense that it > allows NUD_FAILED neighbors to change states upon receipt of a NA, but > by using NUD_STALE it remains consistent with RFC9131 Section 6.1.1. I think that your setup is quite unique and I don't necessarily agree with the statements regarding the CPU load, but it doesn't change my conclusion: IMO it makes sense to transition from FAILED to STALE when receiving NAs (most likely unsolicited given FAILED state). Mention in the commit message that trying to resolve FAILED neighbours by periodically probing them (e.g., using NTF_EXT_MANAGED) adds extra work compared to having the kernel stop ignoring the information that it's getting via NAs. Also mention that the approach taken here is more conservative than IPv4, which by default transitions FAILED neighbours to STALE upon receiving GARPs. Note that you also need to update the RFC 9131 comment in ndisc_recv_na() and the description of accept_untracked_na in Documentation/networking/ip-sysctl.rst. In addition, please add a test case in tools/testing/selftests/net/ndisc_unsolicited_na_test.sh Before submitting, please read: https://docs.kernel.org/next/process/maintainer-netdev.html Run the CI checks locally: https://github.com/linux-netdev/nipa#running-locally And LLM review: https://github.com/sashiko-dev/sashiko#1-local-review-recommended Thanks