[PATCH] dummy -- support hardware address

[PATCH] dummy -- support hardware address

[Stephen Hemminger]

Dummy device comes in handy for testing, but it always has address
of all zero's which isn't a valid ethernet address.  This generates
a simple fake address and allows changing the address.

diff -Nru a/drivers/net/dummy.c b/drivers/net/dummy.c
--- a/drivers/net/dummy.c	Thu Apr  8 11:03:02 2004
+++ b/drivers/net/dummy.c	Thu Apr  8 11:03:02 2004
@@ -86,6 +86,15 @@
 	return dev->priv;
 }
 
+
+static int dummy_set_address(struct net_device *dev, void *p)
+{
+	struct sockaddr *sa = p;
+
+	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
+	return 0;
+}
+
 static struct net_device **dummies;
 
 /* Number of dummy devices to be set up by this module. */
@@ -101,6 +110,16 @@
 
 	if (!dev_dummy)
 		return -ENOMEM;
+
+	/* Generate intial fake hardware address */
+	dev_dummy->dev_addr[0] = 0x00;
+	dev_dummy->dev_addr[1] = 0xdd;
+	dev_dummy->dev_addr[2] = 0xdd;
+	dev_dummy->dev_addr[3] = index >> 16;
+	dev_dummy->dev_addr[4] = index >> 8;
+	dev_dummy->dev_addr[5] = index;
+
+	dev_dummy->set_mac_address = dummy_set_address;
 
 	if ((err = register_netdev(dev_dummy))) {
 		free_netdev(dev_dummy);

Re: [PATCH] dummy -- support hardware address

[David S. Miller]

Stephen, why don't you do what usbnet does?  Look at usbnet_init()
where it goes:

	get_random_bytes (node_id, sizeof node_id);
	node_id [0] &= 0xfe;	// clear multicast bit
	node_id [0] |= 0x02;    // set local assignment bit (IEEE802)

I distinctly remember Alan Cox saying this was the right way
do this and avoid conflicts with Vendor assigned IDs.

Re: [PATCH] dummy -- support hardware address

[Stephen Hemminger]

On Thu, 8 Apr 2004 14:54:03 -0700
"David S. Miller" <davem@redhat.com> wrote:

> 
> Stephen, why don't you do what usbnet does?  Look at usbnet_init()
> where it goes:
> 
> 	get_random_bytes (node_id, sizeof node_id);
> 	node_id [0] &= 0xfe;	// clear multicast bit
> 	node_id [0] |= 0x02;    // set local assignment bit (IEEE802)
> 
> I distinctly remember Alan Cox saying this was the right way
> do this and avoid conflicts with Vendor assigned IDs.

That would work better, just worried about draining the entropy pool
when I create 1000 dummies in a test script.

[PATCH] (1/4) add random_ether_addr to ether_device.h

[Stephen Hemminger]

Since generating a random ethernet address needs to be done
in several drivers, add a random_ether_addr function to etherdevice.h

diff -Nru a/include/linux/etherdevice.h b/include/linux/etherdevice.h
--- a/include/linux/etherdevice.h	Fri Apr  9 11:33:59 2004
+++ b/include/linux/etherdevice.h	Fri Apr  9 11:33:59 2004
@@ -25,6 +25,7 @@
 #define _LINUX_ETHERDEVICE_H
 
 #include <linux/if_ether.h>
+#include <linux/random.h>
 
 #ifdef __KERNEL__
 extern int		eth_header(struct sk_buff *skb, struct net_device *dev,
@@ -64,6 +65,19 @@
 	return !(addr[0]&1) && memcmp( addr, zaddr, 6);
 }
 
+/**
+ * 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)
+{
+	get_random_bytes (addr, ETH_ALEN);
+	addr [0] &= 0xfe;	/* clear multicast bit */
+	addr [0] |= 0x02;	/* set local assignment bit (IEEE802) */
+}
 #endif
 
 #endif	/* _LINUX_ETHERDEVICE_H */

[PATCH] (3/4) usb gadget -- use random_ether_addr

[Stephen Hemminger]

Use new common code in ether_device.h for random_ether_addr.
Same exact code just in one common place.

diff -Nru a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
--- a/drivers/usb/gadget/ether.c	Fri Apr  9 11:39:51 2004
+++ b/drivers/usb/gadget/ether.c	Fri Apr  9 11:39:51 2004
@@ -1804,17 +1804,13 @@
 	/* one random address for the gadget device ... both of these could
 	 * reasonably come from an id prom or a module parameter.
 	 */
-	get_random_bytes (net->dev_addr, ETH_ALEN);
-	net->dev_addr [0] &= 0xfe;	// clear multicast bit
-	net->dev_addr [0] |= 0x02;	// set local assignment bit (IEEE802)
+	random_ether_addr(net->dev_addr);
 
 #ifdef	DEV_CONFIG_CDC
 	/* ... another address for the host, on the other end of the
 	 * link, gets exported through CDC (see CDC spec table 41)
 	 */
-	get_random_bytes (node_id, sizeof node_id);
-	node_id [0] &= 0xfe;	// clear multicast bit
-	node_id [0] |= 0x02;    // set local assignment bit (IEEE802)
+	random_ether_addr(node_id);
 	snprintf (ethaddr, sizeof ethaddr, "%02X%02X%02X%02X%02X%02X",
 		node_id [0], node_id [1], node_id [2],
 		node_id [3], node_id [4], node_id [5]);

[PATCH] (2/4) set random address in dummy

[Stephen Hemminger]

Fix several things in dummy device to make it more useable.
 * add MODULE_PARAM_DESC for num_dummies
 * set initial random ether address
 * allow changing address

diff -Nru a/drivers/net/dummy.c b/drivers/net/dummy.c
--- a/drivers/net/dummy.c	Fri Apr  9 11:33:59 2004
+++ b/drivers/net/dummy.c	Fri Apr  9 11:33:59 2004
@@ -32,6 +32,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/etherdevice.h>
 #include <linux/init.h>
 #include <linux/moduleparam.h>
 
@@ -40,6 +41,17 @@
 static int dummy_xmit(struct sk_buff *skb, struct net_device *dev);
 static struct net_device_stats *dummy_get_stats(struct net_device *dev);
 
+static int dummy_set_address(struct net_device *dev, void *p)
+{
+	struct sockaddr *sa = p;
+
+	if (!is_valid_ether_addr(sa->sa_data)) 
+		return -EADDRNOTAVAIL;
+		
+	memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
+	return 0;
+}
+
 /* fake multicast ability */
 static void set_multicast_list(struct net_device *dev)
 {
@@ -58,6 +70,7 @@
 	dev->get_stats = dummy_get_stats;
 	dev->hard_start_xmit = dummy_xmit;
 	dev->set_multicast_list = set_multicast_list;
+	dev->set_mac_address = dummy_set_address;
 #ifdef CONFIG_NET_FASTROUTE
 	dev->accept_fastpath = dummy_accept_fastpath;
 #endif
@@ -68,6 +81,7 @@
 	dev->flags |= IFF_NOARP;
 	dev->flags &= ~IFF_MULTICAST;
 	SET_MODULE_OWNER(dev);
+	random_ether_addr(dev->dev_addr);
 }
 
 static int dummy_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -90,6 +104,7 @@
 
 /* Number of dummy devices to be set up by this module. */
 module_param(numdummies, int, 0);
+MODULE_PARM_DESC(numdimmies, "Number of dummy psuedo devices");
 
 static int __init dummy_init_one(int index)
 {

[PATCH] (4/4) usbnet -- use random_ether_addr

[Stephen Hemminger]

Same code to generate random_ether_address is in ether_device.h (patch1)
so use it for usbnet.

diff -Nru a/drivers/usb/net/usbnet.c b/drivers/usb/net/usbnet.c
--- a/drivers/usb/net/usbnet.c	Fri Apr  9 11:41:19 2004
+++ b/drivers/usb/net/usbnet.c	Fri Apr  9 11:41:19 2004
@@ -3414,9 +3414,7 @@
 			< sizeof (struct cdc_state)));
 #endif
 
-	get_random_bytes (node_id, sizeof node_id);
-	node_id [0] &= 0xfe;	// clear multicast bit
-	node_id [0] |= 0x02;    // set local assignment bit (IEEE802)
+	random_ether_addr(node_id);
 
  	return usb_register(&usbnet_driver);
 }

Re: [PATCH] (4/4) usbnet -- use random_ether_addr

[David S. Miller]

All 4 patches applied, thanks Stephen.