[PATCH 2/2] UML - Don't roll my own random MAC generator

From: Jeff Dike
Date: Thu Sep 28 2006 - 14:16:53 EST


Use the existing random_ether_addr() instead of cooking up my own
version. Pointed out by Dave Hollis and Jason Lunz.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>
---

arch/um/drivers/net_kern.c | 4 +---
arch/um/drivers/net_user.c | 29 -----------------------------
arch/um/include/net_user.h | 2 --
3 files changed, 1 insertion(+), 34 deletions(-)

Index: linux-2.6.18-mm/arch/um/drivers/net_kern.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/net_kern.c 2006-09-28 12:51:50.000000000 -0400
+++ linux-2.6.18-mm/arch/um/drivers/net_kern.c 2006-09-28 13:00:58.000000000 -0400
@@ -309,9 +309,7 @@ static void setup_etheraddr(char *str, u
return;

random:
- addr[0] = 0xfe;
- addr[1] = 0xfd;
- random_mac(addr);
+ random_ether_addr(addr)
}

static DEFINE_SPINLOCK(devices_lock);
Index: linux-2.6.18-mm/arch/um/drivers/net_user.c
===================================================================
--- linux-2.6.18-mm.orig/arch/um/drivers/net_user.c 2006-09-28 12:51:50.000000000 -0400
+++ linux-2.6.18-mm/arch/um/drivers/net_user.c 2006-09-28 13:00:06.000000000 -0400
@@ -259,32 +259,3 @@ char *split_if_spec(char *str, ...)
va_end(ap);
return str;
}
-
-void random_mac(unsigned char *addr)
-{
- struct timeval tv;
- long n;
- unsigned int seed;
-
- gettimeofday(&tv, NULL);
-
- /* Assume that 20 bits of microseconds and 12 bits of the pid are
- * reasonably unpredictable.
- */
- seed = tv.tv_usec | (os_getpid() << 20);
- srandom(seed);
-
- /* Don't care about endianness here - switching endianness
- * just rearranges what are hopefully random numbers.
- *
- * Assume that RAND_MAX > 65536, so random is called twice and
- * we use 16 bits of the result.
- */
- n = random();
- addr[2] = (n >> 8) & 255;
- addr[3] = n % 255;
-
- n = random();
- addr[4] = (n >> 8) & 255;
- addr[5] = n % 255;
-}
Index: linux-2.6.18-mm/arch/um/include/net_user.h
===================================================================
--- linux-2.6.18-mm.orig/arch/um/include/net_user.h 2006-09-28 12:15:48.000000000 -0400
+++ linux-2.6.18-mm/arch/um/include/net_user.h 2006-09-28 13:01:51.000000000 -0400
@@ -50,6 +50,4 @@ extern char *split_if_spec(char *str, ..

extern int dev_netmask(void *d, void *m);

-extern void random_mac(unsigned char *addr);
-
#endif

-
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