From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from nbd.name (nbd.name [46.4.11.11]) (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 315451FBC89; Thu, 17 Oct 2024 18:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.4.11.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729190376; cv=none; b=VvNvuRyfa53aaWGWuFJoZNAP7o0QPCgsj50YzPsrRssF8dJyvP4+kdDgGP9QRiAmOGf6g5eW2zKk3zOtqAcQYI2wUKP5+Vtgnjjqhlk81zQUAijadWMdKHZ5B3GTvXNv98/cCtWFeV8iBTJvWzOT6fiz7587T58A72mNyxtHCPA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729190376; c=relaxed/simple; bh=FxmywgkNUlS99u+UKR5DQby5kzi44L1odyhv89Zm1SU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aemz0/NQCOEMW16h2YaGaJfkv4o6JgP6ffaJOE5O7B7mZsGOs7QdOLXavJm2nGfXDFC+LiMcRPFGr3su81UErRSo8adnyd35pBwN9/5V7mX8cOgdQRj+1YXTUdP3z2QCAG6y8d/tos8/ZPdqh1hDgF1qFh0uK8Um8DGCxNSArqA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=nbd.name; spf=none smtp.mailfrom=nbd.name; dkim=pass (1024-bit key) header.d=nbd.name header.i=@nbd.name header.b=N5VrXGkg; arc=none smtp.client-ip=46.4.11.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=nbd.name Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=nbd.name Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=nbd.name header.i=@nbd.name header.b="N5VrXGkg" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=nbd.name; s=20160729; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=pXm+8IBFvz1ujYC5/BdUieoeB4O8UBo9KmKYceLh5ts=; b=N5VrXGkgAWFovrbKgWzKyOBDom d46SQYNLOSfMSOWuHmaIHAObkvJwCWdni6bSN1N8KpOLojafzKd21+7Ys++FKchnkzKicr/jZeVOE AB5cuhC6sIIQGfik6tREtlG4yFK3VUEAilMGd9OUAz7A0au20F+kOiUsxFf7OBUtPyU4=; Received: from p4ff13b65.dip0.t-ipconnect.de ([79.241.59.101] helo=nf.local) by ds12 with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.96) (envelope-from ) id 1t1VP4-00AwP2-1f; Thu, 17 Oct 2024 20:39:18 +0200 Message-ID: Date: Thu, 17 Oct 2024 20:39:17 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v1 net-next 00/12] bridge-fastpath and related improvements To: Pablo Neira Ayuso Cc: Eric Woudstra , Nikolay Aleksandrov , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jozsef Kadlecsik , Roopa Prabhu , Matthias Brugger , AngeloGioacchino Del Regno , Jiri Pirko , Sebastian Andrzej Siewior , Lorenzo Bianconi , Frank Wunderlich , Daniel Golle , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, bridge@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org References: <20241013185509.4430-1-ericwouds@gmail.com> <9f9f3cf0-7a78-40f1-b8d5-f06a2d428210@blackwall.org> <0b0a92f2-2e80-429c-8fcd-d4dc162e6e1f@nbd.name> <137aa23a-db21-43c2-8fb0-608cfe221356@gmail.com> From: Felix Fietkau Content-Language: en-US Autocrypt: addr=nbd@nbd.name; keydata= xsDiBEah5CcRBADIY7pu4LIv3jBlyQ/2u87iIZGe6f0f8pyB4UjzfJNXhJb8JylYYRzIOSxh ExKsdLCnJqsG1PY1mqTtoG8sONpwsHr2oJ4itjcGHfn5NJSUGTbtbbxLro13tHkGFCoCr4Z5 Pv+XRgiANSpYlIigiMbOkide6wbggQK32tC20QxUIwCg4k6dtV/4kwEeiOUfErq00TVqIiEE AKcUi4taOuh/PQWx/Ujjl/P1LfJXqLKRPa8PwD4j2yjoc9l+7LptSxJThL9KSu6gtXQjcoR2 vCK0OeYJhgO4kYMI78h1TSaxmtImEAnjFPYJYVsxrhay92jisYc7z5R/76AaELfF6RCjjGeP wdalulG+erWju710Bif7E1yjYVWeA/9Wd1lsOmx6uwwYgNqoFtcAunDaMKi9xVQW18FsUusM TdRvTZLBpoUAy+MajAL+R73TwLq3LnKpIcCwftyQXK5pEDKq57OhxJVv1Q8XkA9Dn1SBOjNB l25vJDFAT9ntp9THeDD2fv15yk4EKpWhu4H00/YX8KkhFsrtUs69+vZQwc0cRmVsaXggRmll dGthdSA8bmJkQG5iZC5uYW1lPsJgBBMRAgAgBQJGoeQnAhsjBgsJCAcDAgQVAggDBBYCAwEC HgECF4AACgkQ130UHQKnbvXsvgCgjsAIIOsY7xZ8VcSm7NABpi91yTMAniMMmH7FRenEAYMa VrwYTIThkTlQzsFNBEah5FQQCACMIep/hTzgPZ9HbCTKm9xN4bZX0JjrqjFem1Nxf3MBM5vN CYGBn8F4sGIzPmLhl4xFeq3k5irVg/YvxSDbQN6NJv8o+tP6zsMeWX2JjtV0P4aDIN1pK2/w VxcicArw0VYdv2ZCarccFBgH2a6GjswqlCqVM3gNIMI8ikzenKcso8YErGGiKYeMEZLwHaxE Y7mTPuOTrWL8uWWRL5mVjhZEVvDez6em/OYvzBwbkhImrryF29e3Po2cfY2n7EKjjr3/141K DHBBdgXlPNfDwROnA5ugjjEBjwkwBQqPpDA7AYPvpHh5vLbZnVGu5CwG7NAsrb2isRmjYoqk wu++3117AAMFB/9S0Sj7qFFQcD4laADVsabTpNNpaV4wAgVTRHKV/kC9luItzwDnUcsZUPdQ f3MueRJ3jIHU0UmRBG3uQftqbZJj3ikhnfvyLmkCNe+/hXhPu9sGvXyi2D4vszICvc1KL4RD aLSrOsROx22eZ26KqcW4ny7+va2FnvjsZgI8h4sDmaLzKczVRIiLITiMpLFEU/VoSv0m1F4B FtRgoiyjFzigWG0MsTdAN6FJzGh4mWWGIlE7o5JraNhnTd+yTUIPtw3ym6l8P+gbvfoZida0 TspgwBWLnXQvP5EDvlZnNaKa/3oBes6z0QdaSOwZCRA3QSLHBwtgUsrT6RxRSweLrcabwkkE GBECAAkFAkah5FQCGwwACgkQ130UHQKnbvW2GgCeMncXpbbWNT2AtoAYICrKyX5R3iMAoMhw cL98efvrjdstUfTCP2pfetyN In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 17.10.24 20:09, Pablo Neira Ayuso wrote: > On Thu, Oct 17, 2024 at 07:06:51PM +0200, Felix Fietkau wrote: >> On 17.10.24 14:39, Pablo Neira Ayuso wrote: >> > On Thu, Oct 17, 2024 at 11:17:09AM +0200, Felix Fietkau wrote: >> > [...] >> > > By the way, based on some reports that I received, I do believe that the >> > > existing forwarding fastpath also doesn't handle roaming properly. >> > > I just didn't have the time to properly look into that yet. >> > >> > I think it should work for the existing forwarding fastpath. >> > >> > - If computer roams from different port, packets follow classic path, >> > then new flow entry is created. The flow old entry expires after 30 >> > seconds. >> > - If route is stale, flow entry is also removed. >> > >> > Maybe I am missing another possible scenario? >> >> I'm mainly talking about the scenario where a computer moves to a different >> switch port on L2 only, so all routes remain the same. >> >> I haven't fully analyzed the issue, but I did find a few potential issues >> with what you're describing. >> >> 1. Since one direction remains the same when a computer roams, a new flow >> entry would probably fail to be added because of an existing entry in the >> flow hash table. > > I don't think so, hash includes iifidx. I'm talking about the side where the input ifindex remains the same, but the output interface doesn't. >> 2. Even with that out of the way, the MTK hardware offload currently does >> not support matching the incoming switch/ethernet port. >> So even if we manage to add an updated entry, the old entry could still be >> kept alive by the hardware. > > OK, that means probably driver needs to address the lack of iifidx in > the matching by dealling with more than one single flow entry to point > to one single hardware entry (refcounting?). If we have multiple colliding entries, I think a more reasonable behavior would be allowing the newer flow to override the older one. >> The issues I found probably wouldn't cause connection hangs in pure L3 >> software flow offload, since it will use the bridge device for xmit instead >> of its members. But since hardware offload needs to redirect traffic to >> individual bridge ports, it could cause connection hangs with stale flow >> entries. > > I would not expect a hang, packets will just flow over classic path > for a little while for the computer that is roaming until the new flow > entry is added. If the hardware still handles traffic, but redirects it to the wrong destination port, the connection will hang. - Felix