uml: improve checking and diagnostics of ethernet MACs

Improve checking and diagnostics for broadcast and multicast Ethernet MAC
addresses, and distinguish between those cases in output; also make sure the
device is assigned a MAC address valid only locally to avoid collisions.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 745c988..071c67a 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -71,6 +71,18 @@
 }
 
 /**
+ * is_local_ether_addr - Determine if the Ethernet address is locally-assigned
+ * one (IEEE 802).
+ * @addr: Pointer to a six-byte array containing the Ethernet address
+ *
+ * Return true if the address is a local address.
+ */
+static inline int is_local_ether_addr(const u8 *addr)
+{
+	return (0x02 & addr[0]);
+}
+
+/**
  * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
  * @addr: Pointer to a six-byte array containing the Ethernet address
  *