[PATCH] net: export device speed and duplex via sysfs

[PATCH] net: export device speed and duplex via sysfs

[Andy Gospodarek]

This exports the link-speed (in Mbps) and duplex of an interface via
sysfs.  This eliminates the need to use ethtool just to check the
link-speed.  Not requiring 'ethtool' and not relying on the SIOCETHTOOL
ioctl should be helpful in an embedded environment where space is at a
premium as well.

NOTE: This patch also intentionally allows non-root users to check the link
speed and duplex -- something not possible with ethtool.

Here's some sample output:

# cat /sys/class/net/eth0/speed 
100
# cat /sys/class/net/eth0/duplex
half
# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Half 1000baseT/Full 
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: 100Mb/s
        Duplex: Half
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Current message level: 0x000000ff (255)
        Link detected: yes

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
---
 net/core/net-sysfs.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ad91e9e..d5964b2 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -130,6 +130,46 @@ static ssize_t show_carrier(struct device *dev,
 	return -EINVAL;
 }
 
+static ssize_t show_speed(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	int ret = -EINVAL;
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
+		struct ethtool_cmd cmd = { ETHTOOL_GSET };
+
+		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)
+			return -EINVAL;
+		ret = sprintf(buf, fmt_dec, cmd.speed);
+	}
+	rtnl_unlock();
+	return ret;
+}
+
+static ssize_t show_duplex(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	int ret = -EINVAL;
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
+		struct ethtool_cmd cmd = { ETHTOOL_GSET };
+
+		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)
+			return -EINVAL;
+		ret = sprintf(buf, "%s\n", cmd.duplex ? "full" : "half");
+	}
+	rtnl_unlock();
+	return ret;
+}
+
 static ssize_t show_dormant(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
@@ -259,6 +299,8 @@ static struct device_attribute net_class_attributes[] = {
 	__ATTR(address, S_IRUGO, show_address, NULL),
 	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
 	__ATTR(carrier, S_IRUGO, show_carrier, NULL),
+	__ATTR(speed, S_IRUGO, show_speed, NULL),
+	__ATTR(duplex, S_IRUGO, show_duplex, NULL),
 	__ATTR(dormant, S_IRUGO, show_dormant, NULL),
 	__ATTR(operstate, S_IRUGO, show_operstate, NULL),
 	__ATTR(mtu, S_IRUGO | S_IWUSR, show_mtu, store_mtu),
-- 
1.6.2.5

Re: [PATCH] net: export device speed and duplex via sysfs

[Eric Dumazet]

Andy Gospodarek a écrit :
> +static ssize_t show_speed(struct device *dev,
> +			  struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +	int ret = -EINVAL;
> +
> +	if (!rtnl_trylock())
> +		return restart_syscall();
> +
> +	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
> +		struct ethtool_cmd cmd = { ETHTOOL_GSET };
> +
> +		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)

		rtnl lock leak ?


> +			return -EINVAL;
> +		ret = sprintf(buf, fmt_dec, cmd.speed);
> +	}
> +	rtnl_unlock();
> +	return ret;
> +}
> +
> +static ssize_t show_duplex(struct device *dev,
> +			   struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +	int ret = -EINVAL;
> +
> +	if (!rtnl_trylock())
> +		return restart_syscall();
> +
> +	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
> +		struct ethtool_cmd cmd = { ETHTOOL_GSET };
> +
> +		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)

		rtnl lock leak ?

> +			return -EINVAL;
> +		ret = sprintf(buf, "%s\n", cmd.duplex ? "full" : "half");
> +	}
> +	rtnl_unlock();
> +	return ret;
> +}
> +

Re: [PATCH] net: export device speed and duplex via sysfs

[Ben Hutchings]

On Fri, 2009-10-02 at 14:07 -0400, Andy Gospodarek wrote:
> This exports the link-speed (in Mbps) and duplex of an interface via
> sysfs.  This eliminates the need to use ethtool just to check the
> link-speed.  Not requiring 'ethtool' and not relying on the SIOCETHTOOL
> ioctl should be helpful in an embedded environment where space is at a
> premium as well.

It's trivial to write an ethtool-lite that does this.  That might be
worth adding to busybox.

> NOTE: This patch also intentionally allows non-root users to check the link
> speed and duplex -- something not possible with ethtool.
[...]

Assuming this is desirable (I'm not sure), wouldn't it would make more
sense to move the permissions check for SIOCETHTOOL so that get_settings
is non-privileged?

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [PATCH v2] net: export device speed and duplex via sysfs

[Andy Gospodarek]

On Fri, Oct 02, 2009 at 08:15:08PM +0200, Eric Dumazet wrote:
> Andy Gospodarek a écrit :
> > +static ssize_t show_speed(struct device *dev,
> > +			  struct device_attribute *attr, char *buf)
> > +{
> > +	struct net_device *netdev = to_net_dev(dev);
> > +	int ret = -EINVAL;
> > +
> > +	if (!rtnl_trylock())
> > +		return restart_syscall();
> > +
> > +	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
> > +		struct ethtool_cmd cmd = { ETHTOOL_GSET };
> > +
> > +		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)
> 
> 		rtnl lock leak ?
> 
> 
> > +			return -EINVAL;
> > +		ret = sprintf(buf, fmt_dec, cmd.speed);
> > +	}
> > +	rtnl_unlock();
> > +	return ret;
> > +}
> > +
> > +static ssize_t show_duplex(struct device *dev,
> > +			   struct device_attribute *attr, char *buf)
> > +{
> > +	struct net_device *netdev = to_net_dev(dev);
> > +	int ret = -EINVAL;
> > +
> > +	if (!rtnl_trylock())
> > +		return restart_syscall();
> > +
> > +	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
> > +		struct ethtool_cmd cmd = { ETHTOOL_GSET };
> > +
> > +		if (netdev->ethtool_ops->get_settings(netdev, &cmd) < 0)
> 
> 		rtnl lock leak ?
> 
> > +			return -EINVAL;
> > +		ret = sprintf(buf, "%s\n", cmd.duplex ? "full" : "half");
> > +	}
> > +	rtnl_unlock();
> > +	return ret;
> > +}
> > +
> 

Thanks for spotting that, Eric.  Here's an updated (and tested patch).
I also switched to using ethtool_cmd_speed to get link speed to get the
'entire' speed.

[PATCH] net: export device speed and duplex via sysfs

This patch exports the link-speed (in Mbps) and duplex of an interface
via sysfs.  This eliminates the need to use ethtool just to check the
link-speed.  Not requiring 'ethtool' and not relying on the SIOCETHTOOL
ioctl should be helpful in an embedded environment where space is at a
premium as well.

NOTE: This patch also intentionally allows non-root users to check the link
speed and duplex -- something not possible with ethtool.

Here's some sample output:

# cat /sys/class/net/eth0/speed 
100
# cat /sys/class/net/eth0/duplex
half
# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Half 1000baseT/Full 
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: 100Mb/s
        Duplex: Half
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Current message level: 0x000000ff (255)
        Link detected: yes


---
 net/core/net-sysfs.c |   40 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 3994680..133dbc4 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -130,6 +130,44 @@ static ssize_t show_carrier(struct device *dev,
 	return -EINVAL;
 }
 
+static ssize_t show_speed(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	int ret = -EINVAL;
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
+		struct ethtool_cmd cmd = { ETHTOOL_GSET };
+
+		if (!netdev->ethtool_ops->get_settings(netdev, &cmd))
+			ret = sprintf(buf, fmt_dec, ethtool_cmd_speed(&cmd));
+	}
+	rtnl_unlock();
+	return ret;
+}
+
+static ssize_t show_duplex(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	int ret = -EINVAL;
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	if (netif_running(netdev) && netdev->ethtool_ops->get_settings) {
+		struct ethtool_cmd cmd = { ETHTOOL_GSET };
+
+		if (!netdev->ethtool_ops->get_settings(netdev, &cmd))
+			ret = sprintf(buf, "%s\n", cmd.duplex ? "full" : "half");
+	}
+	rtnl_unlock();
+	return ret;
+}
+
 static ssize_t show_dormant(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
@@ -259,6 +297,8 @@ static struct device_attribute net_class_attributes[] = {
 	__ATTR(address, S_IRUGO, show_address, NULL),
 	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
 	__ATTR(carrier, S_IRUGO, show_carrier, NULL),
+	__ATTR(speed, S_IRUGO, show_speed, NULL),
+	__ATTR(duplex, S_IRUGO, show_duplex, NULL),
 	__ATTR(dormant, S_IRUGO, show_dormant, NULL),
 	__ATTR(operstate, S_IRUGO, show_operstate, NULL),
 	__ATTR(mtu, S_IRUGO | S_IWUSR, show_mtu, store_mtu),

Re: [PATCH] net: export device speed and duplex via sysfs

[Andy Gospodarek]

On Fri, Oct 02, 2009 at 07:19:14PM +0100, Ben Hutchings wrote:
> On Fri, 2009-10-02 at 14:07 -0400, Andy Gospodarek wrote:
> > This exports the link-speed (in Mbps) and duplex of an interface via
> > sysfs.  This eliminates the need to use ethtool just to check the
> > link-speed.  Not requiring 'ethtool' and not relying on the SIOCETHTOOL
> > ioctl should be helpful in an embedded environment where space is at a
> > premium as well.
> 
> It's trivial to write an ethtool-lite that does this.  That might be
> worth adding to busybox.
> 

It probably would be.  I was just using this as an example of another
use for it.  Embedded usage was not the primary purpose.

> > NOTE: This patch also intentionally allows non-root users to check the link
> > speed and duplex -- something not possible with ethtool.
> [...]
> 
> Assuming this is desirable (I'm not sure), wouldn't it would make more
> sense to move the permissions check for SIOCETHTOOL so that get_settings
> is non-privileged?
> 

That could be done as well I just chose to go a slightly different
direction.

I took a look at /sys/class/net/ethX/ and felt like the information was
pretty complete with the exception of the link speed and duplex, so I
thought it would be a good place to add it.  I personally wouldn't mind
having most of the information presented in ethtool available via sysfs,
but I figured I would walk before running.

Re: [PATCH] net: export device speed and duplex via sysfs

[David Miller]

From: Andy Gospodarek <andy@greyhouse.net>
Date: Fri, 2 Oct 2009 16:01:41 -0400

> I took a look at /sys/class/net/ethX/ and felt like the information was
> pretty complete with the exception of the link speed and duplex, so I
> thought it would be a good place to add it.  I personally wouldn't mind
> having most of the information presented in ethtool available via sysfs,
> but I figured I would walk before running.

I have no objections to this, I applied v2 of your patch to
net-next-2.6, thanks!