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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C9CBC433FE for ; Wed, 19 Oct 2022 18:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229954AbiJSSmL (ORCPT ); Wed, 19 Oct 2022 14:42:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229698AbiJSSmI (ORCPT ); Wed, 19 Oct 2022 14:42:08 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99582196EF4 for ; Wed, 19 Oct 2022 11:42:07 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id a13so26628905edj.0 for ; Wed, 19 Oct 2022 11:42:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=FnEHp+n5E9ORlOqVfiOTZjwtbEGC3D3t4hEl0lUPtBA=; b=LoEEigcpwhA0b4dOQFXlnXsbSzVXh16XqxJxU0B1jYE6CcykOzrccSZDrFc8vpRofk RhYCunqJ/JOa7PxdmHhaDLTEIrx75ELC/x6fzvmP8z0N+lRODd5SfvjsWR08bbIbuACY T6fGOqw4psNQWVeuttxeNj1IQuPHFeyJPK7tl3SRgnWsPs/9TfjuMe2ObJf9fnJiDLX7 E9JAhRVpd+Isr5kncFAcWsky0RnzqZ0ovJ0URJLCbuvLGHaFpWx11OgCbt4syTjupShe HzuAdFpAHj1vAozDxSiDq8a6pTbh4YOaAGJiWU5scV8XSXfF+pHFPWxOSg+78jqgwth9 xqsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FnEHp+n5E9ORlOqVfiOTZjwtbEGC3D3t4hEl0lUPtBA=; b=0DHqEpRM3TiN7WolsnTD1ZL+QrlLVE/AGulQtkW15uH19HkF8t2VF7UimOa8vl2uRZ yz6dK9zfRLMTtivD8yp0NlOSS4cKHE0BM0IGla5iQObSS+ZuD84+rvVgSyKNKSTws+r+ nJlb2mnDQHeAKapBXrNUFh2UfVbHTwPY3rm3898pyYOw1o/w74Z/WMssYC2M+fTSQY75 YBQN9/V8FVkIM+E1IaDlUBBbKVcDYbMh8M3U5RgFzLRa2mqxiZZnsc9CvRkh0sDOrnbz aDtVvdrycPeGfHzdN3bpMgubHXaWz+xMXB00ydAZC4Rv6kBEapiwbG+0ujqj3OY5Lyuc TL/A== X-Gm-Message-State: ACrzQf3+OmHCKxjshExWilgWVxpu6cS+wwE3TGXXdpBmVzjd0x49p+NT L/HwiWp2X2mkEWaEeBVzMVs= X-Google-Smtp-Source: AMsMyM593ieWJV9Uiv4LTeWVb9lQfgS7tQeMsXHu9DW96Daa8+sHCrXDN7Q5sPOm7dclNAMa5XCS+A== X-Received: by 2002:aa7:dd57:0:b0:453:2d35:70bb with SMTP id o23-20020aa7dd57000000b004532d3570bbmr8876722edw.26.1666204926093; Wed, 19 Oct 2022 11:42:06 -0700 (PDT) Received: from skbuf ([188.27.184.197]) by smtp.gmail.com with ESMTPSA id k13-20020a17090627cd00b0077826b92d99sm9331464ejc.12.2022.10.19.11.42.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Oct 2022 11:42:05 -0700 (PDT) Date: Wed, 19 Oct 2022 21:42:03 +0300 From: Vladimir Oltean To: Sergei Antonov Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, andrew@lunn.ch Subject: Re: [PATCH v4 net-next] net: ftmac100: support mtu > 1500 Message-ID: <20221019184203.4ywx3ighj72hjbqz@skbuf> References: <20221019162058.289712-1-saproj@gmail.com> <20221019165516.sgoddwmdx6srmh5e@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Oct 19, 2022 at 09:36:21PM +0300, Sergei Antonov wrote: > On Wed, 19 Oct 2022 at 19:55, Vladimir Oltean wrote: > > > > On Wed, Oct 19, 2022 at 07:20:58PM +0300, Sergei Antonov wrote: > > > The ftmac100 controller considers some packets FTL (frame > > > too long) and drops them. An example of a dropped packet: > > > 6 bytes - dst MAC > > > 6 bytes - src MAC > > > 2 bytes - EtherType IPv4 (0800) > > > 1504 bytes - IPv4 packet > > > > Why do you insist writing these confusing messages? > > Yes, I see now it is not good. And I have a question. > By comparing the packet sent from the sending computer and the packet > received by ftmac100 I found that 4 bytes get appended to the packet: > 80 02 00 00 > I guess it is what 88E6060 switch adds. But it is not 0x8100. Then > what it is? I looked into include/linux/if_vlan.h but still don't get > it. See trailer_rcv() in net/dsa/tag_trailer.c. The switch is telling you that this is a packet received from source port 2 via a tail tag (trailer, i.e. added to the end of the packet, meaning right before the FCS). I know that mv88e6060 uses this tagging protocol because this is what mv88e6060_get_tag_protocol() returns. Still nothing to do with if_vlan.h. Also see if Documentation/networking/dsa/dsa.rst answers some of the other questions.