[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>

3 files changed, 58 insertions, 5 deletions

diff --git a/include/linux/if.h b/include/linux/if.h
index 12c6f6d157c..374e20ad8b0 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -33,7 +33,7 @@
 #define IFF_LOOPBACK    0x8             /* is a loopback net            */
 #define IFF_POINTOPOINT 0x10            /* interface is has p-p link    */
 #define IFF_NOTRAILERS  0x20            /* avoid use of trailers        */
-#define IFF_RUNNING     0x40            /* interface running and carrier ok */
+#define IFF_RUNNING     0x40            /* interface RFC2863 OPER_UP    */
 #define IFF_NOARP       0x80            /* no ARP protocol              */
 #define IFF_PROMISC     0x100           /* receive all packets          */
 #define IFF_ALLMULTI    0x200           /* receive all multicast packets*/
@@ -43,12 +43,16 @@
 
 #define IFF_MULTICAST   0x1000          /* Supports multicast           */
 
-#define IFF_VOLATILE    (IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|IFF_MASTER|IFF_SLAVE|IFF_RUNNING)
-
 #define IFF_PORTSEL     0x2000          /* can set media type           */
 #define IFF_AUTOMEDIA   0x4000          /* auto media select active     */
 #define IFF_DYNAMIC     0x8000          /* dialup device with changing addresses*/
 
+#define IFF_LOWER_UP    0x10000         /* driver signals L1 up         */
+#define IFF_DORMANT     0x20000         /* driver signals dormant       */
+
+#define IFF_VOLATILE    (IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|\
+                IFF_MASTER|IFF_SLAVE|IFF_RUNNING|IFF_LOWER_UP|IFF_DORMANT)
+
 /* Private (from user) interface flags (netdevice->priv_flags). */
 #define IFF_802_1Q_VLAN 0x1             /* 802.1Q VLAN device.          */
 #define IFF_EBRIDGE     0x2             /* Ethernet bridging device.    */
@@ -83,6 +87,22 @@
 #define IF_PROTO_FR_ETH_PVC 0x200B
 #define IF_PROTO_RAW    0x200C          /* RAW Socket                   */
 
+/* RFC 2863 operational status */
+enum {
+        IF_OPER_UNKNOWN,
+        IF_OPER_NOTPRESENT,
+        IF_OPER_DOWN,
+        IF_OPER_LOWERLAYERDOWN,
+        IF_OPER_TESTING,
+        IF_OPER_DORMANT,
+        IF_OPER_UP,
+};
+
+/* link modes */
+enum {
+        IF_LINK_MODE_DEFAULT,
+        IF_LINK_MODE_DORMANT,   /* limit upward transition to dormant */
+};
 
 /*
  *      Device mapping structure. I'd just gone off and designed a 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7fda03d338d..b825be201bc 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)
 {
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index d50482ba27f..edccefb4518 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -733,6 +733,8 @@ enum
 #define IFLA_MAP IFLA_MAP
         IFLA_WEIGHT,
 #define IFLA_WEIGHT IFLA_WEIGHT
+        IFLA_OPERSTATE,
+        IFLA_LINKMODE,
         __IFLA_MAX
 };