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 mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBC4FF54ADF for ; Tue, 24 Mar 2026 17:12:17 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3492340B91; Tue, 24 Mar 2026 18:12:17 +0100 (CET) Received: from mail-dy1-f178.google.com (mail-dy1-f178.google.com [74.125.82.178]) by mails.dpdk.org (Postfix) with ESMTP id 704C040B95 for ; Tue, 24 Mar 2026 18:12:15 +0100 (CET) Received: by mail-dy1-f178.google.com with SMTP id 5a478bee46e88-2c0f754e756so1861796eec.1 for ; Tue, 24 Mar 2026 10:12:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1774372334; x=1774977134; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=igHrx8wFtcC2gk9p805wYgEpCiZDpMZfk5UpdIGOCm4=; b=EishPbrW6ypjuQ42q/NU2cx+9wlGP/9M/Yb+mw+L784Qowjb7aBoDvbIiLtx7qcM/s aLZsvjR+LmBhQxtn+VC1di3GgnhBlyR5ABUoHT4KshHC8bfs4+VsA8MR+U5smJtw6jBG Gt+K2b1UYvoOb23qa8p6KRxbhsQtg9Oy8+4Xsz1YEC5XkR5zc5qZtReGZYNSG+qkqv1R oKn9KELn9OmEMPGsV5G+W+kXf7QYkvgmL/ZE/3TnlcgW3IaXaCWEZXdKtftyrOtD98n/ setRqncrjJshs5zsnB+htmMINFwR5d8KJKs5mNz1PckRiIHU+w6bzrH3MgKPcrz44Ii5 I5Uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774372334; x=1774977134; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=igHrx8wFtcC2gk9p805wYgEpCiZDpMZfk5UpdIGOCm4=; b=SAf8rNSMvnqGVZ4lZPIEo1s5eFnKT5WIr2qfyQ+n3tr3Cz2aJlQ/9uQMQkGK8kMyQG WSy7mSFmMv13SEH2Bs8IqpGhfs3o2qtJJxzi0GETcPd18fFP/ClnFN0qZw/4ZzNInmdT qloiqrliPPbl6Bv0oSadVcgYN0oIdJwU7dUsHGxqptvqkOo+nEI34AWTOiy25V8f4l6/ abNeAGYkpNy6dlD+zWyqY3bdquBYigtkYJntNUXnbWxrLaUraAUeYHdMeiEFQYjk/ndb t+YqeN0j958qvr35edJWv7iBjqAobRORFQGfy5ssijbKZzkGWvh8eIzje8GsbezbDwQC 5ZVQ== X-Forwarded-Encrypted: i=1; AJvYcCXtDLVnC+Cpi2K0dLsGOxjFqsQW4ga2ZhDYAr64rXWU58wHsAjn+zKO+MM4op98PzRRq7I=@dpdk.org X-Gm-Message-State: AOJu0YxxzG8r3y4Qe/5j1z3uRN6rzIfFwH0AeAUgVIJx0oh071JTLKHZ rAv6rBKkI5xb5AB4/zlqyKYZp/Ggjfu8jYM91ynM74v2QYeQ7IlvA9kyOqEk+ZBdCSs= X-Gm-Gg: ATEYQzzjw0M+ASEwKOWRNpiK/GtkUc2/MD6Fte3PYaghmH/dGtxJAxYTABRzzuMcviE jLszOzn4xuwHkp5hs7Tn991HjxuI/ymV+sugl145+VTCAy8UmYomtjGjB/0WDSDCO1LV8n8wjte zoWlfipdaj2eKNL0zxnfzq5BrPneIsiLi69TK5YNQr22GfCdTj1479g0Uh0x7xTyNrZ5ncsHeA6 vpxQ+dgrmeMg9wTcdq3btwdhGE+gXySkmZjkJIowtyse1ZT2EvHeYIKVOFWgb3D+gRY8bhVLByz jb6FpnqQo9xcL6yIbN7A2VHioVvUG3w74OvcBFxfAr3sVX1pz7FSIRUKEKkGbjwUZ2mVxo7Jt// 270Y5VxC3V5cMz2URTpGfkDe5AXkjS8Azgim/SvmkAW2fjlYE9/Vby50wki0+0RwhJMoIsFZeMN /18x6AWhweehtBIrY3QfbYo452ouBQ0GgRAQ4= X-Received: by 2002:a05:7301:1984:b0:2be:aa:9a4a with SMTP id 5a478bee46e88-2c15d18640dmr101312eec.0.1774372334427; Tue, 24 Mar 2026 10:12:14 -0700 (PDT) Received: from phoenix.local ([104.202.29.139]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c10b2ce04asm15837160eec.21.2026.03.24.10.12.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Mar 2026 10:12:14 -0700 (PDT) Date: Tue, 24 Mar 2026 10:12:09 -0700 From: Stephen Hemminger To: Morten =?UTF-8?B?QnLDuHJ1cA==?= Cc: "Bruce Richardson" , , "Reshma Pattan" Subject: Re: [PATCH v20 25/25] app/pdump: preserve VLAN tags in captured packets Message-ID: <20260324101209.04ffae54@phoenix.local> In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35F6579A@smartserver.smartshare.dk> References: <20260106182823.192350-1-stephen@networkplumber.org> <20260310161356.194553-1-stephen@networkplumber.org> <20260310161356.194553-26-stephen@networkplumber.org> <98CBD80474FA8B44BF855DF32C47DC35F6579A@smartserver.smartshare.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Mon, 16 Mar 2026 16:55:29 +0100 Morten Br=C3=B8rup wrote: > >=20 > > This is an example of something I previously flagged. Like with real > > hardware, I think the PMD should be inserting the VLAN tag into the > > packet > > as part of the Tx function, not the prepare function. =20 >=20 > Agree with Bruce on this. > For simple stuff like VLAN offload, applications should not be required t= o call tx_prep first. >=20 > However, the Tx function is supposed to not modify the packets; relevant = when refcnt > 1. >=20 > Instead of modifying the packet data to insert/strip the VLAN tag, > perhaps the driver can split the write/read operation into multiple write= /read operations: > 1. the Ethernet header > 2. the VLAN tag > 3. the remaining packet data >=20 > I haven't really followed the pcap driver, so maybe my suggestion doesn't= make sense. The prepare code and VLAN was copied from virtio. I assume virtio is widely used already.