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 X-Spam-Level: X-Spam-Status: No, score=-0.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,URIBL_SBL,URIBL_SBL_A autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8AD8FC48BD7 for ; Thu, 27 Jun 2019 15:29:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CA2820B7C for ; Thu, 27 Jun 2019 15:29:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=networkplumber-org.20150623.gappssmtp.com header.i=@networkplumber-org.20150623.gappssmtp.com header.b="KU/d5ypG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726500AbfF0P3a (ORCPT ); Thu, 27 Jun 2019 11:29:30 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:43425 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726187AbfF0P3a (ORCPT ); Thu, 27 Jun 2019 11:29:30 -0400 Received: by mail-pf1-f196.google.com with SMTP id i189so1400355pfg.10 for ; Thu, 27 Jun 2019 08:29:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=8fuHdHdiEjIUTcichDGMVPHPCDjsVoWx+4OQONVTd7s=; b=KU/d5ypGfSyplSI981Ib1YoHQEXoC5vTAXwS/8No/eps/K7NVnsmQP4x1qAY2DzEJd /dhyQ9LIZ/utyiKsL8/Yq75HH7BlQrrj+uHNWl5tSvA4FCCT7WC3tl5QQtns2l9WDygp 4mbEXo+SZqJk8GB4E9w7ZBsjYSYc8M1S3FfkvssRlL+yuG5GNDkKo6EGAz2s3rsC1iip Hj/NeBj/tCo35jujljAU8TV/908IRclCrQnIdPNkC1jYOLcXaTNsFnuZTkJPVXlZNQcE bRKHomxipn/pbVjLpuFBnuJoW3TYpLLCphIGsJ2WUX6QcdKAmj15QTLXl8p0gj/N3ynn zU1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8fuHdHdiEjIUTcichDGMVPHPCDjsVoWx+4OQONVTd7s=; b=E4fUnfvA6SXF0FOARBybT6spKTN9UMzm0iCVIarvBfrAIbYd/0P4giOdW1AeNWnUV9 gKC7gJxgpmXAc+gXduJmP/V6o3BhnP/o586qx+Kb0Z95kmydK1jthl6s0327tSaHf8DW YjTs9H/gsNLFZlfzdAqic4PgpGXiu52LQelI0AwBlzITDW5dJ8wqqVDhYSX7AEksh0rW vPvefH1IwpQKEkLomjCaVSahqC0AXhnNmM1/3UbThZw9ty0/s6nG/eSnHAsf21+rmK+B MBF+4mQTK8I2XD8xBbA/31mUMbfK4Bl3r5pCelt7QqKvZ8QXkjMD9ztu3n+zB93t6YBa +C1Q== X-Gm-Message-State: APjAAAU4u/PmzbXHrj8x2+3B5Cc8EcAs9B3afTpUPzr1GKZrxEUnZHoS UmIhmtkvv7oKO0wVvmTHO4tl0Q== X-Google-Smtp-Source: APXvYqwRuvY+WetJSJ9ORbtJWZoxmPjLH0RY9sEWqzgeGWXRehnhX1qBPK96HOIB87F3oz5w4rKBJA== X-Received: by 2002:a63:4c14:: with SMTP id z20mr4307052pga.360.1561649369170; Thu, 27 Jun 2019 08:29:29 -0700 (PDT) Received: from hermes.lan (204-195-22-127.wavecable.com. [204.195.22.127]) by smtp.gmail.com with ESMTPSA id z4sm2978904pfa.142.2019.06.27.08.29.28 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 27 Jun 2019 08:29:29 -0700 (PDT) Date: Thu, 27 Jun 2019 08:29:22 -0700 From: Stephen Hemminger To: Jiri Pirko Cc: netdev@vger.kernel.org, davem@davemloft.net, jakub.kicinski@netronome.com, sthemmin@microsoft.com, dsahern@gmail.com, mlxsw@mellanox.com Subject: Re: [RFC] longer netdev names proposal Message-ID: <20190627082922.289225f7@hermes.lan> In-Reply-To: <20190627094327.GF2424@nanopsycho> References: <20190627094327.GF2424@nanopsycho> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 27 Jun 2019 11:43:27 +0200 Jiri Pirko wrote: > Hi all. > > In the past, there was repeatedly discussed the IFNAMSIZ (16) limit for > netdevice name length. Now when we have PF and VF representors > with port names like "pfXvfY", it became quite common to hit this limit: > 0123456789012345 > enp131s0f1npf0vf6 > enp131s0f1npf0vf22 > > Since IFLA_NAME is just a string, I though it might be possible to use > it to carry longer names as it is. However, the userspace tools, like > iproute2, are doing checks before print out. So for example in output of > "ip addr" when IFLA_NAME is longer than IFNAMSIZE, the netdevice is > completely avoided. > > So here is a proposal that might work: > 1) Add a new attribute IFLA_NAME_EXT that could carry names longer than > IFNAMSIZE, say 64 bytes. The max size should be only defined in kernel, > user should be prepared for any string size. > 2) Add a file in sysfs that would indicate that NAME_EXT is supported by > the kernel. > 3) Udev is going to look for the sysfs indication file. In case when > kernel supports long names, it will do rename to longer name, setting > IFLA_NAME_EXT. If not, it does what it does now - fail. > 4) There are two cases that can happen during rename: > A) The name is shorter than IFNAMSIZ > -> both IFLA_NAME and IFLA_NAME_EXT would contain the same string: > original IFLA_NAME = eth0 > original IFLA_NAME_EXT = eth0 > renamed IFLA_NAME = enp5s0f1npf0vf1 > renamed IFLA_NAME_EXT = enp5s0f1npf0vf1 > B) The name is longer tha IFNAMSIZ > -> IFLA_NAME would contain the original one, IFLA_NAME_EXT would > contain the new one: > original IFLA_NAME = eth0 > original IFLA_NAME_EXT = eth0 > renamed IFLA_NAME = eth0 > renamed IFLA_NAME_EXT = enp131s0f1npf0vf22 > > This would allow the old tools to work with "eth0" and the new > tools would work with "enp131s0f1npf0vf22". In sysfs, there would > be symlink from one name to another. > > Also, there might be a warning added to kernel if someone works > with IFLA_NAME that the userspace tool should be upgraded. > > Eventually, only IFLA_NAME_EXT is going to be used by everyone. > > I'm aware there are other places where similar new attribute > would have to be introduced too (ip rule for example). > I'm not saying this is a simple work. > > Question is what to do with the ioctl api (get ifindex etc). I would > probably leave it as is and push tools to use rtnetlink instead. > > Any ideas why this would not work? Any ideas how to solve this > differently? > > Thanks! > > Jiri > I looked into this in the past, but then rejected it because there are so many tools that use names, not just iproute2. Plus long names are very user unfriendly.