[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, 33 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7fda03d338d1..b825be201bce 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -230,7 +230,8 @@ enum netdev_state_t
         __LINK_STATE_SCHED,
         __LINK_STATE_NOCARRIER,
         __LINK_STATE_RX_SCHED,
-        __LINK_STATE_LINKWATCH_PENDING
+        __LINK_STATE_LINKWATCH_PENDING,
+        __LINK_STATE_DORMANT,
 };
 
 
@@ -335,11 +336,14 @@ struct net_device
          */
 
 
-        unsigned short          flags;  /* interface flags (a la BSD)   */
+        unsigned int            flags;  /* interface flags (a la BSD)   */
         unsigned short          gflags;
         unsigned short          priv_flags; /* Like 'flags' but invisible to userspace. */
         unsigned short          padded; /* How much padding added by alloc_netdev() */
 
+        unsigned char           operstate; /* RFC2863 operstate */
+        unsigned char           link_mode; /* mapping policy to operstate */
+
         unsigned                mtu;    /* interface MTU value          */
         unsigned short          type;   /* interface hardware type      */
         unsigned short          hard_header_len;        /* hardware hdr length  */
@@ -714,6 +718,10 @@ static inline void dev_put(struct net_device *dev)
 /* Carrier loss detection, dial on demand. The functions netif_carrier_on
  * and _off may be called from IRQ context, but it is caller
  * who is responsible for serialization of these calls.
+ *
+ * The name carrier is inappropriate, these functions should really be
+ * called netif_lowerlayer_*() because they represent the state of any
+ * kind of lower layer not just hardware media.
  */
 
 extern void linkwatch_fire_event(struct net_device *dev);
@@ -729,6 +737,29 @@ extern void netif_carrier_on(struct net_device *dev);
 
 extern void netif_carrier_off(struct net_device *dev);
 
+static inline void netif_dormant_on(struct net_device *dev)
+{
+        if (!test_and_set_bit(__LINK_STATE_DORMANT, &dev->state))
+                linkwatch_fire_event(dev);
+}
+
+static inline void netif_dormant_off(struct net_device *dev)
+{
+        if (test_and_clear_bit(__LINK_STATE_DORMANT, &dev->state))
+                linkwatch_fire_event(dev);
+}
+
+static inline int netif_dormant(const struct net_device *dev)
+{
+        return test_bit(__LINK_STATE_DORMANT, &dev->state);
+}
+
+
+static inline int netif_oper_up(const struct net_device *dev) {
+        return (dev->operstate == IF_OPER_UP ||
+                dev->operstate == IF_OPER_UNKNOWN /* backward compat */);
+}
+
 /* Hot-plugging. */
 static inline int netif_device_present(struct net_device *dev)
 {