Hi
This series implements a new sysfs attribute for netdevs called
"name_assign_type". It provides an integer that describes where an interface
name comes from. See Patch #1 for a description of this attribute. It is
modelled after the existing "addr_assign_type" attribute.
The main use-case is to allow udev to skip applying reliable ifnames to virtual
devices. For instance, if wifi-P2P devices are created, wpas already provides a
suitable naming-policy and udev shouldn't touch these devices. Same is true for
other virtual devices.
The idea is that if a device-name was provided by user-space, we should always
prefer fixing this naming-policy instead of making udev rename the device. For
kernel provided names that's hardly possible, though. Providing the
naming-policy source via sysfs is thus a simple way to see whether renames are
needed.
Additionally, this field allows to detect whether a netdev has been manually
renamed, which is quite useful for debugging and during crash-recovery.
Thanks
David
David Herrmann (4):
net: add name_assign_type netdev attribute
mac80211: set NET_NAME_USER for user-space created ifs
ath6kl: set NET_NAME_USER for P2P ifs
brcmfmac: set NET_NAME_USER for P2P ifs
drivers/net/wireless/ath/ath6kl/cfg80211.c | 5 ++++-
drivers/net/wireless/ath/ath6kl/cfg80211.h | 1 +
drivers/net/wireless/ath/ath6kl/core.c | 4 ++--
drivers/net/wireless/brcm80211/brcmfmac/p2p.c | 1 +
include/linux/netdevice.h | 6 ++++++
net/core/dev.c | 7 +++++++
net/core/net-sysfs.c | 2 ++
net/core/rtnetlink.c | 2 ++
net/mac80211/iface.c | 1 +
9 files changed, 26 insertions(+), 3 deletions(-)
--
1.9.0
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 <[email protected]>
---
include/linux/netdevice.h | 6 ++++++
net/core/dev.c | 7 +++++++
net/core/net-sysfs.c | 2 ++
net/core/rtnetlink.c | 2 ++
4 files changed, 17 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e8eeebd..d3a11c8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -74,6 +74,11 @@ void netdev_set_default_ethtool_ops(struct net_device *dev,
#define NET_RX_SUCCESS 0 /* keep 'em coming, baby */
#define NET_RX_DROP 1 /* packet dropped */
+/* interface name assignment types */
+#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 */
+
/*
* Transmit return codes: transmit return codes originate from three different
* namespaces:
@@ -1165,6 +1170,7 @@ 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/net/core/dev.c b/net/core/dev.c
index b1b0c8d..3608fb2 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 9388624..72a8ce5 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -104,6 +104,7 @@ static ssize_t netdev_store(struct device *dev, struct device_attribute *attr,
}
NETDEVICE_SHOW_RO(dev_id, fmt_hex);
+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);
@@ -375,6 +376,7 @@ static struct attribute *net_class_attrs[] = {
&dev_attr_dev_id.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 1a0dac2..e10baa0 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1962,6 +1962,8 @@ 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);
--
1.9.0
Netdevs created via nl80211 (currently only P2P ifs) have names provided
by user-space. Therefore, set the naming-policy to NET_NAME_USER so it is
correctly shown in sysfs.
Cc: Arend van Spriel <[email protected]>
Signed-off-by: David Herrmann <[email protected]>
---
drivers/net/wireless/brcm80211/brcmfmac/p2p.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
index fc4f98b..6af4d26 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
@@ -2310,6 +2310,7 @@ struct wireless_dev *brcmf_p2p_add_vif(struct wiphy *wiphy, const char *name,
goto fail;
}
+ ifp->ndev->name_assign_type = NET_NAME_USER;
strncpy(ifp->ndev->name, name, sizeof(ifp->ndev->name) - 1);
err = brcmf_net_attach(ifp, true);
if (err) {
--
1.9.0
The nl80211 interface allows creating new netdevs from user-space. The
name is *always* provided by user-space, so we should set NET_NAME_USER to
provide that information via sysfs.
This allows udev to not rename dynamically created wifi devices (like wifi
P2P devices).
Cc: Johannes Berg <[email protected]>
Signed-off-by: David Herrmann <[email protected]>
---
net/mac80211/iface.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index ce1c443..35561bd 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1620,6 +1620,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
+ IEEE80211_ENCRYPT_HEADROOM;
ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
+ ndev->name_assign_type = NET_NAME_USER;
ret = dev_alloc_name(ndev, ndev->name);
if (ret < 0) {
free_netdev(ndev);
--
1.9.0
P2P netdevs and other devices that are created via nl80211 from user-space
have a name provided by user-space. Therefore, set NET_NAME_USER so this
is correctly shown in sysfs.
Cc: Kalle Valo <[email protected]>
Signed-off-by: David Herrmann <[email protected]>
---
drivers/net/wireless/ath/ath6kl/cfg80211.c | 5 ++++-
drivers/net/wireless/ath/ath6kl/cfg80211.h | 1 +
drivers/net/wireless/ath/ath6kl/core.c | 4 ++--
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index fd4c89d..74598ed 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -1516,7 +1516,8 @@ static struct wireless_dev *ath6kl_cfg80211_add_iface(struct wiphy *wiphy,
return ERR_PTR(-EINVAL);
}
- wdev = ath6kl_interface_add(ar, name, type, if_idx, nw_type);
+ wdev = ath6kl_interface_add(ar, name, NET_NAME_USER, type,
+ if_idx, nw_type);
if (!wdev)
return ERR_PTR(-ENOMEM);
@@ -3625,6 +3626,7 @@ void ath6kl_cfg80211_vif_cleanup(struct ath6kl_vif *vif)
}
struct wireless_dev *ath6kl_interface_add(struct ath6kl *ar, const char *name,
+ unsigned char name_assign_type,
enum nl80211_iftype type,
u8 fw_vif_idx, u8 nw_type)
{
@@ -3661,6 +3663,7 @@ struct wireless_dev *ath6kl_interface_add(struct ath6kl *ar, const char *name,
ndev->dev_addr[4] ^= 0x80;
}
+ ndev->name_assign_type = name_assign_type;
init_netdev(ndev);
ath6kl_init_control_info(vif);
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.h b/drivers/net/wireless/ath/ath6kl/cfg80211.h
index b59becd..5aa57a7 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.h
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.h
@@ -25,6 +25,7 @@ enum ath6kl_cfg_suspend_mode {
};
struct wireless_dev *ath6kl_interface_add(struct ath6kl *ar, const char *name,
+ unsigned char name_assign_type,
enum nl80211_iftype type,
u8 fw_vif_idx, u8 nw_type);
void ath6kl_cfg80211_ch_switch_notify(struct ath6kl_vif *vif, int freq,
diff --git a/drivers/net/wireless/ath/ath6kl/core.c b/drivers/net/wireless/ath/ath6kl/core.c
index 4b46adb..3cc8145 100644
--- a/drivers/net/wireless/ath/ath6kl/core.c
+++ b/drivers/net/wireless/ath/ath6kl/core.c
@@ -195,8 +195,8 @@ int ath6kl_core_init(struct ath6kl *ar, enum ath6kl_htc_type htc_type)
rtnl_lock();
/* Add an initial station interface */
- wdev = ath6kl_interface_add(ar, "wlan%d", NL80211_IFTYPE_STATION, 0,
- INFRA_NETWORK);
+ wdev = ath6kl_interface_add(ar, "wlan%d", NET_NAME_ENUM,
+ NL80211_IFTYPE_STATION, 0, INFRA_NETWORK);
rtnl_unlock();
--
1.9.0
Given the premise of your patches,
> +++ b/net/mac80211/iface.c
> @@ -1620,6 +1620,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
> + IEEE80211_ENCRYPT_HEADROOM;
> ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
>
> + ndev->name_assign_type = NET_NAME_USER;
this is wrong because we call this in main.c with a "wlan%d" argument
for the name, which gets expanded.
johannes
Hi
On Thu, Feb 27, 2014 at 3:53 PM, Johannes Berg
<[email protected]> wrote:
> Given the premise of your patches,
>
>> +++ b/net/mac80211/iface.c
>> @@ -1620,6 +1620,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
>> + IEEE80211_ENCRYPT_HEADROOM;
>> ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
>>
>> + ndev->name_assign_type = NET_NAME_USER;
>
> this is wrong because we call this in main.c with a "wlan%d" argument
> for the name, which gets expanded.
Whoops, yeah, same issue as with ath6kl where I fixed it with a
separate "name_assign_type" argument. I will do the same here for v2.
Thanks
David
David Herrmann <[email protected]> writes:
> P2P netdevs and other devices that are created via nl80211 from user-space
> have a name provided by user-space. Therefore, set NET_NAME_USER so this
> is correctly shown in sysfs.
>
> Cc: Kalle Valo <[email protected]>
> Signed-off-by: David Herrmann <[email protected]>
Looks good to me.
Acked-by: Kalle Valo <[email protected]>
Can I take this to my ath.git tree?
--
Kalle Valo
On Thu, Feb 27, 2014 at 3:47 PM, David Herrmann <[email protected]> wrote:
> This series implements a new sysfs attribute for netdevs called
> "name_assign_type". It provides an integer that describes where an interface
> name comes from. See Patch #1 for a description of this attribute. It is
> modelled after the existing "addr_assign_type" attribute.
>
> The main use-case is to allow udev to skip applying reliable ifnames to virtual
> devices. For instance, if wifi-P2P devices are created, wpas already provides a
> suitable naming-policy and udev shouldn't touch these devices. Same is true for
> other virtual devices.
> The idea is that if a device-name was provided by user-space, we should always
> prefer fixing this naming-policy instead of making udev rename the device. For
> kernel provided names that's hardly possible, though. Providing the
> naming-policy source via sysfs is thus a simple way to see whether renames are
> needed.
>
> Additionally, this field allows to detect whether a netdev has been manually
> renamed, which is quite useful for debugging and during crash-recovery.
Moreover, it would be useful for udev to reliably know if some other
userspace process already renamed a device, so we know not to touch
it. This can easily happen for instance if some renaming happens in
the initrd or from script called from udev rules.
Acked-by: Tom Gundersen <[email protected]>
> David Herrmann (4):
> net: add name_assign_type netdev attribute
> mac80211: set NET_NAME_USER for user-space created ifs
> ath6kl: set NET_NAME_USER for P2P ifs
> brcmfmac: set NET_NAME_USER for P2P ifs
>
> drivers/net/wireless/ath/ath6kl/cfg80211.c | 5 ++++-
> drivers/net/wireless/ath/ath6kl/cfg80211.h | 1 +
> drivers/net/wireless/ath/ath6kl/core.c | 4 ++--
> drivers/net/wireless/brcm80211/brcmfmac/p2p.c | 1 +
> include/linux/netdevice.h | 6 ++++++
> net/core/dev.c | 7 +++++++
> net/core/net-sysfs.c | 2 ++
> net/core/rtnetlink.c | 2 ++
> net/mac80211/iface.c | 1 +
> 9 files changed, 26 insertions(+), 3 deletions(-)
>
> --
> 1.9.0
>
Kalle Valo <[email protected]> writes:
> David Herrmann <[email protected]> writes:
>
>> P2P netdevs and other devices that are created via nl80211 from user-space
>> have a name provided by user-space. Therefore, set NET_NAME_USER so this
>> is correctly shown in sysfs.
>>
>> Cc: Kalle Valo <[email protected]>
>> Signed-off-by: David Herrmann <[email protected]>
>
> Looks good to me.
>
> Acked-by: Kalle Valo <[email protected]>
>
> Can I take this to my ath.git tree?
Nevermind, I saw the first patch now. Just CCing random patches like
this is confusing for the recipients, better to CC the full patchset.
--
Kalle Valo
On Thu, 2014-02-27 at 15:56 +0100, David Herrmann wrote:
> >> +++ b/net/mac80211/iface.c
> >> @@ -1620,6 +1620,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
> >> + IEEE80211_ENCRYPT_HEADROOM;
> >> ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
> >>
> >> + ndev->name_assign_type = NET_NAME_USER;
> >
> > this is wrong because we call this in main.c with a "wlan%d" argument
> > for the name, which gets expanded.
>
> Whoops, yeah, same issue as with ath6kl where I fixed it with a
> separate "name_assign_type" argument. I will do the same here for v2.
I'm not sure that helps - the user could potentially pass "foobar%d" as
the interface name and get a number assigned by the kernel. In that case
you probably *don't* want to set it to "name assigned by user"?
Maybe this whole thing can just be handled in __dev_alloc_name() since
no kernel user should pass just a string without "%d" in it.
johannes
Hi
On Thu, Feb 27, 2014 at 5:18 PM, Johannes Berg
<[email protected]> wrote:
> On Thu, 2014-02-27 at 15:56 +0100, David Herrmann wrote:
>
>> >> +++ b/net/mac80211/iface.c
>> >> @@ -1620,6 +1620,7 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
>> >> + IEEE80211_ENCRYPT_HEADROOM;
>> >> ndev->needed_tailroom = IEEE80211_ENCRYPT_TAILROOM;
>> >>
>> >> + ndev->name_assign_type = NET_NAME_USER;
>> >
>> > this is wrong because we call this in main.c with a "wlan%d" argument
>> > for the name, which gets expanded.
>>
>> Whoops, yeah, same issue as with ath6kl where I fixed it with a
>> separate "name_assign_type" argument. I will do the same here for v2.
>
> I'm not sure that helps - the user could potentially pass "foobar%d" as
> the interface name and get a number assigned by the kernel. In that case
> you probably *don't* want to set it to "name assigned by user"?
>
> Maybe this whole thing can just be handled in __dev_alloc_name() since
> no kernel user should pass just a string without "%d" in it.
Nope, I still want to set NET_NAME_USER in that case. It's not about
the %d suffix, it's about who chooses the suffix. If wpas decides to
use p2p-wlanX-%d, this is fine, as it's a virtual device where stable
IDs are not required at all.
Thanks
David
On 02/27/2014 03:47 PM, David Herrmann wrote:
> Netdevs created via nl80211 (currently only P2P ifs) have names provided
> by user-space. Therefore, set the naming-policy to NET_NAME_USER so it is
> correctly shown in sysfs.
>
- Cc: Arend van Spriel <[email protected]>
+ Acked-by: Arend van Spriel <[email protected]>
> Signed-off-by: David Herrmann <[email protected]>
> ---
> drivers/net/wireless/brcm80211/brcmfmac/p2p.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
> index fc4f98b..6af4d26 100644
> --- a/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
> +++ b/drivers/net/wireless/brcm80211/brcmfmac/p2p.c
> @@ -2310,6 +2310,7 @@ struct wireless_dev *brcmf_p2p_add_vif(struct wiphy *wiphy, const char *name,
> goto fail;
> }
>
> + ifp->ndev->name_assign_type = NET_NAME_USER;
> strncpy(ifp->ndev->name, name, sizeof(ifp->ndev->name) - 1);
> err = brcmf_net_attach(ifp, true);
> if (err) {
>