From: Hannes Reinecke <hare@suse.de>
Date: Sun, 1 Jun 2014 22:26:20 +0000 (+0100)
Subject: [ethernet] Provide eth_random_addr() to generate random Ethernet addresses
X-Git-Tag: v1.20.1~1161
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d630052e6f44ce215503fb7f20819a1382ebfa9b;p=thirdparty%2Fipxe.git

[ethernet] Provide eth_random_addr() to generate random Ethernet addresses

Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/include/ipxe/ethernet.h b/src/include/ipxe/ethernet.h
index 5ffc45b73..b28a6b8e1 100644
--- a/src/include/ipxe/ethernet.h
+++ b/src/include/ipxe/ethernet.h
@@ -87,6 +87,7 @@ extern int eth_pull ( struct net_device *netdev, struct io_buffer *iobuf,
 		      const void **ll_dest, const void **ll_source,
 		      uint16_t *net_proto, unsigned int *flags );
 extern void eth_init_addr ( const void *hw_addr, void *ll_addr );
+extern void eth_random_addr ( void *hw_addr );
 extern const char * eth_ntoa ( const void *ll_addr );
 extern int eth_mc_hash ( unsigned int af, const void *net_addr,
 			 void *ll_addr );
diff --git a/src/net/ethernet.c b/src/net/ethernet.c
index a2e565899..03978c2a8 100644
--- a/src/net/ethernet.c
+++ b/src/net/ethernet.c
@@ -20,6 +20,7 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <stdint.h>
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <byteswap.h>
@@ -112,6 +113,21 @@ void eth_init_addr ( const void *hw_addr, void *ll_addr ) {
 	memcpy ( ll_addr, hw_addr, ETH_ALEN );
 }
 
+/**
+ * Generate random Ethernet address
+ *
+ * @v hw_addr		Generated hardware address
+ */
+void eth_random_addr ( void *hw_addr ) {
+	uint8_t *addr = hw_addr;
+	unsigned int i;
+
+	for ( i = 0 ; i < ETH_ALEN ; i++ )
+		addr[i] = random();
+	addr[0] &= ~0x01; /* Clear multicast bit */
+	addr[0] |= 0x02; /* Set locally-assigned bit */
+}
+
 /**
  * Transcribe Ethernet address
  *