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
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 821d309..effb784 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -130,6 +130,44 @@
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 @@
__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),