[NET] core: add RFC2863 operstate

this patch adds a dormant flag to network devices, RFC2863 operstate derived
from these flags and possibility for userspace interaction. It allows drivers
to signal that a device is unusable for user traffic without disabling
queueing (and therefore the possibility for protocol establishment traffic to
flow) and a userspace supplicant (WPA, 802.1X) to mark a device unusable
without changes to the driver.

It is the result of our long discussion. However I must admit that it
represents what Jamal and I agreed on with compromises towards Krzysztof, but
Thomas and Krzysztof still disagree with some parts. Anyway I think it should
be applied.

Signed-off-by: Stefan Rompf <stefan@loplof.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 0 deletions

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index e8b2acbc8ea..21b68464cab 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -91,6 +91,7 @@ NETDEVICE_SHOW(iflink, fmt_dec);
 NETDEVICE_SHOW(ifindex, fmt_dec);
 NETDEVICE_SHOW(features, fmt_long_hex);
 NETDEVICE_SHOW(type, fmt_dec);
+NETDEVICE_SHOW(link_mode, fmt_dec);
 
 /* use same locking rules as GIFHWADDR ioctl's */
 static ssize_t format_addr(char *buf, const unsigned char *addr, int len)
@@ -133,6 +134,43 @@ static ssize_t show_carrier(struct class_device *dev, char *buf)
 	return -EINVAL;
 }
 
+static ssize_t show_dormant(struct class_device *dev, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+
+	if (netif_running(netdev))
+		return sprintf(buf, fmt_dec, !!netif_dormant(netdev));
+
+	return -EINVAL;
+}
+
+static const char *operstates[] = {
+	"unknown",
+	"notpresent", /* currently unused */
+	"down",
+	"lowerlayerdown",
+	"testing", /* currently unused */
+	"dormant",
+	"up"
+};
+
+static ssize_t show_operstate(struct class_device *dev, char *buf)
+{
+	const struct net_device *netdev = to_net_dev(dev);
+	unsigned char operstate;
+
+	read_lock(&dev_base_lock);
+	operstate = netdev->operstate;
+	if (!netif_running(netdev))
+		operstate = IF_OPER_DOWN;
+	read_unlock(&dev_base_lock);
+
+	if (operstate >= sizeof(operstates))
+		return -EINVAL; /* should not happen */
+
+	return sprintf(buf, "%s\n", operstates[operstate]);
+}
+
 /* read-write attributes */
 NETDEVICE_SHOW(mtu, fmt_dec);
 
@@ -190,9 +228,12 @@ static struct class_device_attribute net_class_attributes[] = {
 	__ATTR(ifindex, S_IRUGO, show_ifindex, NULL),
 	__ATTR(features, S_IRUGO, show_features, NULL),
 	__ATTR(type, S_IRUGO, show_type, NULL),
+	__ATTR(link_mode, S_IRUGO, show_link_mode, NULL),
 	__ATTR(address, S_IRUGO, show_address, NULL),
 	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
 	__ATTR(carrier, S_IRUGO, show_carrier, 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),
 	__ATTR(flags, S_IRUGO | S_IWUSR, show_flags, store_flags),
 	__ATTR(tx_queue_len, S_IRUGO | S_IWUSR, show_tx_queue_len,