net: implement random_ether_addr

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/net.h b/include/net.h
index 709e76c895..c695e5f72a 100644
--- a/include/net.h
+++ b/include/net.h
@@ -17,6 +17,7 @@
 #include <param.h>
 #include <malloc.h>
 #include <stdlib.h>
+#include <clock.h>
 #include <asm/byteorder.h>	/* for nton* / ntoh* stuff */
 
 
@@ -332,6 +333,21 @@ static inline int is_broadcast_ether_addr(const u8 *addr)
 }
 
 /**
+ * random_ether_addr - Generate software assigned random Ethernet address
+ * @addr: Pointer to a six-byte array containing the Ethernet address
+ *
+ * Generate a random Ethernet address (MAC) that is not multicast
+ * and has the local assigned bit set.
+ */
+static inline void random_ether_addr(u8 *addr)
+{
+	srand(get_time_ns());
+	get_random_bytes(addr, 6);
+	addr [0] &= 0xfe;	/* clear multicast bit */
+	addr [0] |= 0x02;	/* set local assignment bit (IEEE802) */
+}
+
+/**
  * is_valid_ether_addr - Determine if the given Ethernet address is valid
  * @addr: Pointer to a six-byte array containing the Ethernet address
  *