From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6B871C433F5 for ; Wed, 11 May 2022 08:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:Subject:From:References:Cc:To: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+EmzhvGJW82faUuGHQq0wsrwkfX6jcuZ7BXfw7vGBQw=; b=NXvlJUhCR4Gbkd U+SsbRQzCqaFFAsd48jD30s437mczUcG3T0F3ZYO3s3pcEdj4sb8iZMSsP/qs5WKHvf5IDj44mE0j 9n6Vmecn6VDS3ex8cy+RIWm4hWfP4yTlvWbo44YqWTqJsK3oN+FnJAmIHm5o9Vn59/3qlmVGcTn4F dy1x+KbPKyb1bKCOZLyFftSrC+zP0z/DXi4mc80hmSzEhucC6qlOL3w2i9ywBj8Hbu8d+HLrnCBW8 f95AOpGIN/fw7nqejTBLzMLihmpCfIWx3OAWskFa/STxgYPDp5WhfiUeFPdW93fdRm32wCx3v1Fqw LziaPLFbgQ40hjLFAg7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1noi3K-0062eZ-V7; Wed, 11 May 2022 08:50:39 +0000 Received: from nbd.name ([2a01:4f8:221:3d45::2]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1noi3H-0062dR-93; Wed, 11 May 2022 08:50:36 +0000 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:Subject: From:References:Cc:To: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=K9S0p/PZ8mVH19diTHdZftm0WUxvYRUVPKuMIoWWr6A=; b=gqqRzYAyEQaZPglJ6z5hwVhmcy ti0G3HCYz7sxUTKH6vXINCJA/N7H7NrCT7ghoWlveD5910asAltd71LxWbLjTQYXZJiVb+lD2XIVF Q5YP3XqAugpioX/H9Vuw2lQqxASCD96KfQxSsxTbfzofUXvfyy5ANESzjP4VZ1SGusDA=; Received: from p200300daa70ef200e12105daa054647e.dip0.t-ipconnect.de ([2003:da:a70e:f200:e121:5da:a054:647e] helo=nf.local) by ds12 with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1noi30-00040B-O3; Wed, 11 May 2022 10:50:18 +0200 Message-ID: <376b13ac-d90b-24e0-37ed-a96d8e5f80da@nbd.name> Date: Wed, 11 May 2022 10:50:17 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Content-Language: en-US To: Vladimir Oltean Cc: Sean Wang , Landen Chao , DENG Qingfang , Andrew Lunn , Vivien Didelot , Florian Fainelli , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org References: <20220510094014.68440-1-nbd@nbd.name> <20220510123724.i2xqepc56z4eouh2@skbuf> <5959946d-1d34-49b9-1abe-9f9299cc194e@nbd.name> <20220510165233.yahsznxxb5yq6rai@skbuf> <20220510222101.od3n7gk3cofwhbks@skbuf> From: Felix Fietkau Subject: Re: [PATCH v2] net: dsa: tag_mtk: add padding for tx packets In-Reply-To: <20220510222101.od3n7gk3cofwhbks@skbuf> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220511_015035_612763_BFAE219E X-CRM114-Status: GOOD ( 14.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Vladimir, On 11.05.22 00:21, Vladimir Oltean wrote: > It sounds as if this is masking a problem on the receiver end, because > not only does my enetc port receive the packet, it also replies to the > ARP request. > > pc # sudo tcpreplay -i eth1 arp-broken.pcap > root@debian:~# ip addr add 192.168.42.1/24 dev eno0 > root@debian:~# tcpdump -i eno0 -e -n --no-promiscuous-mode arp > tcpdump: verbose output suppressed, use -v[v]... for full protocol decode > listening on eno0, link-type EN10MB (Ethernet), snapshot length 262144 bytes > 22:18:58.846753 f4:d4:88:5e:6f:d2 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.42.1 tell 192.168.42.173, length 46 > 22:18:58.846806 00:04:9f:05:f4:ab > f4:d4:88:5e:6f:d2, ethertype ARP (0x0806), length 42: Reply 192.168.42.1 is-at 00:04:9f:05:f4:ab, length 28 > ^C > 2 packets captured > 2 packets received by filter > 0 packets dropped by kernel > > What MAC/driver has trouble with these packets? Is there anything wrong > in ethtool stats? Do they even reach software? You can also use > "dropwatch -l kas" for some hints if they do. For some reason I can't reproduce the issue of ARPs not getting replies anymore. The garbage data is still present in the ARP packets without my patch though. So regardless of whether ARP packets are processed correctly or if they just trip up on some receivers under specific conditions, I believe my patch is valid and should be applied. Who knows, maybe the garbage padding even leaks some data from previous packets, or some other information from within the switch. - Felix _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel