[PATCH] net: set default DEVTYPE for all ethernet based devices

[PATCH] net: set default DEVTYPE for all ethernet based devices

[Tom Gundersen]

In systemd's networkd and udevd, we would like to give the administrator a
simple way to filter net devices by their DEVTYPE [0][1]. Other software
such as ConnMan and NetworkManager uses a similar filtering already.

Currently, plain ethernet devices have DEVTYPE=(null). This patch sets the
devtype to "ethernet" instead. This avoids the need for special-casing the
DEVTYPE=(null) case in userspace, and also avoids false positives, as there
are several other types of netdevs that also have DEVTYPE=(null).

Notice that this is done, as suggested by Marcel, in alloc_etherdev_mqs(),
and as best I can tell it will not give any false positives. I considered
doing it in ether_setup() instead as that seemed more intuitive, but that
would give a lot of false positives indeed.

[0]: <http://www.freedesktop.org/software/systemd/man/systemd-networkd.service.html#Type>
[1]: <http://www.freedesktop.org/software/systemd/man/udev.html#Type>

Signed-off-by: Tom Gundersen <teg@jklm.no>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Kay Sievers <kay@vrfy.org>
---
 net/ethernet/eth.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 8f032ba..b76dc17 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -369,6 +369,10 @@ void ether_setup(struct net_device *dev)
 }
 EXPORT_SYMBOL(ether_setup);
 
+static const struct device_type eth_type = {
+	.name = "ethernet",
+};
+
 /**
  * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
  * @sizeof_priv: Size of additional driver-private structure to be allocated
@@ -387,7 +391,13 @@ EXPORT_SYMBOL(ether_setup);
 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
 				      unsigned int rxqs)
 {
-	return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
+	struct net_device* dev;
+
+	dev = alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
+	if (dev)
+		dev->dev.type = &eth_type;
+
+	return dev;
 }
 EXPORT_SYMBOL(alloc_etherdev_mqs);
 
-- 
1.8.5.3

Re: [PATCH] net: set default DEVTYPE for all ethernet based devices

[Veaceslav Falico]

On Thu, Jan 30, 2014 at 02:20:02PM +0100, Tom Gundersen wrote:
>In systemd's networkd and udevd, we would like to give the administrator a
>simple way to filter net devices by their DEVTYPE [0][1]. Other software
>such as ConnMan and NetworkManager uses a similar filtering already.
>
>Currently, plain ethernet devices have DEVTYPE=(null). This patch sets the
>devtype to "ethernet" instead. This avoids the need for special-casing the
>DEVTYPE=(null) case in userspace, and also avoids false positives, as there
>are several other types of netdevs that also have DEVTYPE=(null).

There are quite a few users at least in usb and wireless drivers:

net#git grep alloc_etherdev drivers/net/wireless/ drivers/net/usb | wc -l
18

In usb, though, there might be some false positives of this grep, as
there are a few devices which might be considered ethernet.

>
>Notice that this is done, as suggested by Marcel, in alloc_etherdev_mqs(),
>and as best I can tell it will not give any false positives. I considered
>doing it in ether_setup() instead as that seemed more intuitive, but that
>would give a lot of false positives indeed.
>
>[0]: <http://www.freedesktop.org/software/systemd/man/systemd-networkd.service.html#Type>
>[1]: <http://www.freedesktop.org/software/systemd/man/udev.html#Type>
>
>Signed-off-by: Tom Gundersen <teg@jklm.no>
>Cc: Marcel Holtmann <marcel@holtmann.org>
>Cc: Greg KH <gregkh@linuxfoundation.org>
>Cc: Kay Sievers <kay@vrfy.org>
>---
> net/ethernet/eth.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
>diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
>index 8f032ba..b76dc17 100644
>--- a/net/ethernet/eth.c
>+++ b/net/ethernet/eth.c
>@@ -369,6 +369,10 @@ void ether_setup(struct net_device *dev)
> }
> EXPORT_SYMBOL(ether_setup);
>
>+static const struct device_type eth_type = {
>+	.name = "ethernet",
>+};
>+
> /**
>  * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
>  * @sizeof_priv: Size of additional driver-private structure to be allocated
>@@ -387,7 +391,13 @@ EXPORT_SYMBOL(ether_setup);
> struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
> 				      unsigned int rxqs)
> {
>-	return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
>+	struct net_device* dev;
>+
>+	dev = alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
>+	if (dev)
>+		dev->dev.type = &eth_type;
>+
>+	return dev;
> }
> EXPORT_SYMBOL(alloc_etherdev_mqs);
>
>-- 
>1.8.5.3
>
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Re: [PATCH] net: set default DEVTYPE for all ethernet based devices

[Tom Gundersen]

Hi Veaceslav,

Thanks for your quick reply.

On Thu, Jan 30, 2014 at 4:05 PM, Veaceslav Falico <vfalico@redhat.com> wrote:
> On Thu, Jan 30, 2014 at 02:20:02PM +0100, Tom Gundersen wrote:
>>
>> In systemd's networkd and udevd, we would like to give the administrator a
>> simple way to filter net devices by their DEVTYPE [0][1]. Other software
>> such as ConnMan and NetworkManager uses a similar filtering already.
>>
>> Currently, plain ethernet devices have DEVTYPE=(null). This patch sets the
>> devtype to "ethernet" instead. This avoids the need for special-casing the
>> DEVTYPE=(null) case in userspace, and also avoids false positives, as
>> there
>> are several other types of netdevs that also have DEVTYPE=(null).
>
>
> There are quite a few users at least in usb and wireless drivers:
>
> net#git grep alloc_etherdev drivers/net/wireless/ drivers/net/usb | wc -l
> 18
>
> In usb, though, there might be some false positives of this grep, as
> there are a few devices which might be considered ethernet.

Ah, yes I missed the #define of alloc_etherdev(). Looking through
these, it shouldn't be too hard to keep this patch and additionally
fix up the false positives to opt-out of setting the DEVTYPE. Does
that sound like something that would be acceptable?

Cheers,

Tom

Re: [PATCH] net: set default DEVTYPE for all ethernet based devices

[Veaceslav Falico]

On Fri, Jan 31, 2014 at 01:54:03AM +0100, Tom Gundersen wrote:
>Hi Veaceslav,
>
>Thanks for your quick reply.
>
>On Thu, Jan 30, 2014 at 4:05 PM, Veaceslav Falico <vfalico@redhat.com> wrote:
>> On Thu, Jan 30, 2014 at 02:20:02PM +0100, Tom Gundersen wrote:
>>>
>>> In systemd's networkd and udevd, we would like to give the administrator a
>>> simple way to filter net devices by their DEVTYPE [0][1]. Other software
>>> such as ConnMan and NetworkManager uses a similar filtering already.
>>>
>>> Currently, plain ethernet devices have DEVTYPE=(null). This patch sets the
>>> devtype to "ethernet" instead. This avoids the need for special-casing the
>>> DEVTYPE=(null) case in userspace, and also avoids false positives, as
>>> there
>>> are several other types of netdevs that also have DEVTYPE=(null).
>>
>>
>> There are quite a few users at least in usb and wireless drivers:
>>
>> net#git grep alloc_etherdev drivers/net/wireless/ drivers/net/usb | wc -l
>> 18
>>
>> In usb, though, there might be some false positives of this grep, as
>> there are a few devices which might be considered ethernet.
>
>Ah, yes I missed the #define of alloc_etherdev(). Looking through
>these, it shouldn't be too hard to keep this patch and additionally
>fix up the false positives to opt-out of setting the DEVTYPE. Does
>that sound like something that would be acceptable?

Sure, I guess it would be nice to add something like alloc_netdev() (or any
other name for 'generic' network device) and alloc_wirelessdev() for
wireless - so that alloc_*dev() would be small inline wrappers for
alloc_netdev() and setting the type. I didn't check deep enough though, so
I might have overlooked something :).

I've taken a bit deeper look at USB network drivers and it seems that all
of them are ethernet, whilst usbnet (generic network framework for usb
networking devices, used for quite a few drivers) already tries to guess
the type - default is ethernet, and if there are W[WL]AN flags set - update
devtype accordingly. So you might want to take a look at usbnet_probe(), if
that'll suit your needs.

>
>Cheers,
>
>Tom

Re: [PATCH] net: set default DEVTYPE for all ethernet based devices

[David Miller]

From: Tom Gundersen <teg@jklm.no>
Date: Thu, 30 Jan 2014 14:20:02 +0100

> In systemd's networkd and udevd, we would like to give the administrator a
> simple way to filter net devices by their DEVTYPE [0][1]. Other software
> such as ConnMan and NetworkManager uses a similar filtering already.
> 
> Currently, plain ethernet devices have DEVTYPE=(null). This patch sets the
> devtype to "ethernet" instead. This avoids the need for special-casing the
> DEVTYPE=(null) case in userspace, and also avoids false positives, as there
> are several other types of netdevs that also have DEVTYPE=(null).
> 
> Notice that this is done, as suggested by Marcel, in alloc_etherdev_mqs(),
> and as best I can tell it will not give any false positives. I considered
> doing it in ether_setup() instead as that seemed more intuitive, but that
> would give a lot of false positives indeed.
> 
> [0]: <http://www.freedesktop.org/software/systemd/man/systemd-networkd.service.html#Type>
> [1]: <http://www.freedesktop.org/software/systemd/man/udev.html#Type>
> 
> Signed-off-by: Tom Gundersen <teg@jklm.no>

Assuming that all users of alloc_etherdev*() are ethernet devices is
really not going to work.