From patchwork Mon Mar 17 17:03:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Herrmann X-Patchwork-Id: 331081 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 92C0D2C0096 for ; Tue, 18 Mar 2014 04:04:32 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755176AbaCQREK (ORCPT ); Mon, 17 Mar 2014 13:04:10 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:43176 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754103AbaCQREI (ORCPT ); Mon, 17 Mar 2014 13:04:08 -0400 Received: by mail-bk0-f46.google.com with SMTP id v15so422532bkz.19 for ; Mon, 17 Mar 2014 10:04:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=DggcpeL24GWnhE7XUCuKANiwVjW0FaqXZbf3XQ7bQqg=; b=psTZAY87oL1HjNaPE1paO7dpPlVxpYBAT+AjFDZHvnkU5zUBktXZ+xNAxPz9sJfngK jtHtvrh46cT9pVBQBFEhg3h+Ke5QjT3foM8OWPcfq0ILSS6WssV5IRVw5FBMq+JyygCp gNVe8rMbe2lVixrPUvSBoQQUct4KWyjN/nHJtMZL92YL94pJKRFB6j4wdO9EPWp4XsWI ik5kR0AKWF6AsvLRmQJ4pZKlMUZ7aZHNXkgLFQ0wmGSmJdEAqX+mZVz/hJ0KdveWDo4I OjM/piDiCfFGOcJCZeJfToCNhaCy5x03uBuTVPT4ndwuGkV+aJ6hJE9NSs5wwtMtBR2x jXjQ== X-Received: by 10.205.18.3 with SMTP id qe3mr411161bkb.87.1395075846238; Mon, 17 Mar 2014 10:04:06 -0700 (PDT) Received: from david-tp.localdomain (stgt-5f716d13.pool.mediaWays.net. [95.113.109.19]) by mx.google.com with ESMTPSA id dj6sm14113914bkc.5.2014.03.17.10.04.03 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 17 Mar 2014 10:04:05 -0700 (PDT) From: David Herrmann To: netdev@vger.kernel.org Cc: "David S. Miller" , Tom Gundersen , Johannes berg , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, Ben Hutchings , David Herrmann Subject: [PATCH v3 1/4] net: add name_assign_type netdev attribute Date: Mon, 17 Mar 2014 18:03:45 +0100 Message-Id: <1395075825-5824-1-git-send-email-dh.herrmann@gmail.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1394990490-1076-2-git-send-email-dh.herrmann@gmail.com> References: <1394990490-1076-2-git-send-email-dh.herrmann@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The name_assign_type attribute gives hints where the interface name of a given net-device comes from. Three different values are currently defined: NET_NAME_ENUM: This is the default. The ifname is provided by the kernel with an enumerated suffix. Names may be reused and unstable. NET_NAME_USER: The ifname was provided by user-space during net-device setup. NET_NAME_RENAMED: The net-device has been renamed via RTNL. Once this type is set, it cannot change again. This attribute comes in handy for reliable net-device names. If an ifname is provided by user-space, we can safely assume that the naming-policy avoids reuse and is stable. Only if it was set by the kernel, the interfaces might need to be renamed. The NET_NAME_RENAMED value allows us to detect whether some-one else already renamed the device, in which case we shouldn't touch it again. The NET_NAME_USER value allows us to detect whether some other naming policy created the device, in which case there's no need to rename it. The most significant use-case is to detect virtual wifi-P2P devices, which are named by wpa_supplicant et al. We shouldn't rename them as wpas already provides a proper naming-policy. Note that this patch only provides the core infrastructure. The different net-dev types need to be manually fixed to use NET_NAME_USER instead of the default (NET_NAME_ENUM). NET_NAME_ENUM is the least restrictive, though, so it seems safe to use it as fallback for non-converted net-dev types. Signed-off-by: David Herrmann Acked-by: Tom Gundersen --- v3: - move constants to uapi header (suggested by Ben) include/linux/netdevice.h | 1 + include/uapi/linux/netdevice.h | 4 ++++ net/core/dev.c | 7 +++++++ net/core/net-sysfs.c | 2 ++ net/core/rtnetlink.c | 2 ++ 5 files changed, 16 insertions(+) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index b8d8c80..6698e87 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1248,6 +1248,7 @@ struct net_device { * of the interface. */ char name[IFNAMSIZ]; + unsigned char name_assign_type; /* name assignment type */ /* device name hash chain, please keep it close to name[] */ struct hlist_node name_hlist; diff --git a/include/uapi/linux/netdevice.h b/include/uapi/linux/netdevice.h index 6b9500b..ea963e4 100644 --- a/include/uapi/linux/netdevice.h +++ b/include/uapi/linux/netdevice.h @@ -36,6 +36,10 @@ /* Initial net device group. All devices belong to group 0 by default. */ #define INIT_NETDEV_GROUP 0 +/* interface name assignment types (sysfs name_assign_type attribute) */ +#define NET_NAME_ENUM 0 /* enumerated by kernel (default) */ +#define NET_NAME_USER 1 /* provided by user-space */ +#define NET_NAME_RENAMED 2 /* renamed by user-space */ /* Media selection options. */ diff --git a/net/core/dev.c b/net/core/dev.c index 587f9fb..4a2b360 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1083,6 +1083,7 @@ static int dev_get_valid_name(struct net *net, int dev_change_name(struct net_device *dev, const char *newname) { char oldname[IFNAMSIZ]; + unsigned char old_assign_type; int err = 0; int ret; struct net *net; @@ -1109,10 +1110,14 @@ int dev_change_name(struct net_device *dev, const char *newname) return err; } + old_assign_type = dev->name_assign_type; + dev->name_assign_type = NET_NAME_RENAMED; + rollback: ret = device_rename(&dev->dev, dev->name); if (ret) { memcpy(dev->name, oldname, IFNAMSIZ); + dev->name_assign_type = old_assign_type; write_seqcount_end(&devnet_rename_seq); return ret; } @@ -1141,6 +1146,8 @@ rollback: write_seqcount_begin(&devnet_rename_seq); memcpy(dev->name, oldname, IFNAMSIZ); memcpy(oldname, newname, IFNAMSIZ); + dev->name_assign_type = old_assign_type; + old_assign_type = NET_NAME_RENAMED; goto rollback; } else { pr_err("%s: name change rollback failed: %d\n", diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index daed9a6..886403e 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -105,6 +105,7 @@ static ssize_t netdev_store(struct device *dev, struct device_attribute *attr, NETDEVICE_SHOW_RO(dev_id, fmt_hex); NETDEVICE_SHOW_RO(dev_port, fmt_dec); +NETDEVICE_SHOW_RO(name_assign_type, fmt_dec); NETDEVICE_SHOW_RO(addr_assign_type, fmt_dec); NETDEVICE_SHOW_RO(addr_len, fmt_dec); NETDEVICE_SHOW_RO(iflink, fmt_dec); @@ -377,6 +378,7 @@ static struct attribute *net_class_attrs[] = { &dev_attr_dev_port.attr, &dev_attr_iflink.attr, &dev_attr_ifindex.attr, + &dev_attr_name_assign_type.attr, &dev_attr_addr_assign_type.attr, &dev_attr_addr_len.attr, &dev_attr_link_mode.attr, diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index fc122fd..f1bd0fe 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1967,6 +1967,8 @@ replay: } dev->ifindex = ifm->ifi_index; + if (tb[IFLA_IFNAME]) + dev->name_assign_type = NET_NAME_USER; if (ops->newlink) { err = ops->newlink(net, dev, tb, data);