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/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index 20963f1..cd466e3 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -283,7 +283,7 @@
#endif
}
-static void setup_etheraddr(char *str, unsigned char *addr)
+static void setup_etheraddr(char *str, unsigned char *addr, char *name)
{
char *end;
int i;
@@ -302,15 +302,32 @@
}
str = end + 1;
}
- if(addr[0] & 1){
+ if (is_multicast_ether_addr(addr)) {
printk(KERN_ERR
- "Attempt to assign a broadcast ethernet address to a "
+ "Attempt to assign a multicast ethernet address to a "
"device disallowed\n");
goto random;
}
+ if (!is_valid_ether_addr(addr)) {
+ printk(KERN_ERR
+ "Attempt to assign an invalid ethernet address to a "
+ "device disallowed\n");
+ goto random;
+ }
+ if (!is_local_ether_addr(addr)) {
+ printk(KERN_WARNING
+ "Warning: attempt to assign a globally valid ethernet address to a "
+ "device\n");
+ printk(KERN_WARNING "You should better enable the 2nd rightmost bit "
+ "in the first byte of the MAC, i.e. "
+ "%02x:%02x:%02x:%02x:%02x:%02x\n",
+ addr[0] | 0x02, addr[1], addr[2], addr[3], addr[4], addr[5]);
+ }
return;
random:
+ printk(KERN_INFO
+ "Choosing a random ethernet address for device %s\n", name);
random_ether_addr(addr);
}
@@ -331,6 +348,7 @@
struct net_device *dev;
struct uml_net_private *lp;
int save, err, size;
+ char name[sizeof(dev->name)];
size = transport->private_size + sizeof(struct uml_net_private) +
sizeof(((struct uml_net_private *) 0)->user);
@@ -344,7 +362,13 @@
INIT_LIST_HEAD(&device->list);
device->index = n;
- setup_etheraddr(mac, device->mac);
+ /* If this name ends up conflicting with an existing registered
+ * netdevice, that is OK, register_netdev{,ice}() will notice this
+ * and fail.
+ */
+ snprintf(name, sizeof(name), "eth%d", n);
+
+ setup_etheraddr(mac, device->mac, name);
printk(KERN_INFO "Netdevice %d ", n);
printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
@@ -375,11 +399,7 @@
goto out_free_netdev;
SET_NETDEV_DEV(dev,&device->pdev.dev);
- /* If this name ends up conflicting with an existing registered
- * netdevice, that is OK, register_netdev{,ice}() will notice this
- * and fail.
- */
- snprintf(dev->name, sizeof(dev->name), "eth%d", n);
+ strcpy(dev->name, name);
device->dev = dev;
/*
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
*