hmm, on second thought, I think I would prefer the attached patch
(compiled but not tested).
Hardware usually returns all 1's when it's not present, or not working,
so think checking for addresses filled with 1's is a good idea too.
I also took the patch from alan's tree and made the memcmp against
six-byte 'zaddr' rather than a seven-byte string :)
--
Jeff Garzik | May you have warm words on a cold evening,
Building 1024 | a full mooon on a dark night,
MandrakeSoft | and a smooth road all the way to your door.
Index: include/linux/etherdevice.h
===================================================================
RCS file: /cvsroot/gkernel/linux_2_4/include/linux/etherdevice.h,v
retrieving revision 1.1.1.14.4.2
diff -u -r1.1.1.14.4.2 etherdevice.h
--- include/linux/etherdevice.h 2001/03/21 14:10:50 1.1.1.14.4.2
+++ include/linux/etherdevice.h 2001/03/22 13:37:15
@@ -46,6 +46,25 @@
memcpy (dest->data, src, len);
}
+/**
+ * is_valid_ether_addr - Determine if the given Ethernet address is valid
+ * @addr: Pointer to a six-byte array containing the Ethernet address
+ *
+ * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
+ * a multicast address, and is not FF:FF:FF:FF:FF:FF.
+ *
+ * Return true if the address is valid.
+ */
+static inline int is_valid_ether_addr( u8 *addr )
+{
+ const char zaddr[6] = {0,};
+ const char faddr[6] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
+
+ return !(addr[0]&1) &&
+ memcmp( addr, zaddr, 6) &&
+ memcmp( addr, faddr, 6);
+}
+
#endif
#endif /* _LINUX_ETHERDEVICE_H */
