usbnet: modern method to get random MAC

The driver generates a random MAC once on load
and uses it over and over, including on two devices
needing a random MAC at the same time.

Jakub suggested revamping the driver to the modern
API for setting a random MAC rather than fixing
the old stuff.

The bug is as old as the driver.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://patch.msgid.link/20240829175201.670718-1-oneukum@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 9fd516e8bb107be4acd01fdef8ca3e19fb604b5b..18eb5ba436df69027bff6e34bb13bf302ad2da4c 100644 (file)
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -61,9 +61,6 @@
 
 /*-------------------------------------------------------------------------*/
 
-// randomly generated ethernet address
-static u8      node_id [ETH_ALEN];
-
 /* use ethtool to change the level for any given device */
 static int msg_level = -1;
 module_param (msg_level, int, 0);
@@ -1725,7 +1722,6 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 
        dev->net = net;
        strscpy(net->name, "usb%d", sizeof(net->name));
-       eth_hw_addr_set(net, node_id);
 
        /* rx and tx sides can use different message sizes;
         * bind() should set rx_urb_size in that case.
@@ -1801,9 +1797,9 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
                goto out4;
        }
 
-       /* let userspace know we have a random address */
-       if (ether_addr_equal(net->dev_addr, node_id))
-               net->addr_assign_type = NET_ADDR_RANDOM;
+       /* this flags the device for user space */
+       if (!is_valid_ether_addr(net->dev_addr))
+               eth_hw_addr_random(net);
 
        if ((dev->driver_info->flags & FLAG_WLAN) != 0)
                SET_NETDEV_DEVTYPE(net, &wlan_type);
@@ -2211,7 +2207,6 @@ static int __init usbnet_init(void)
        BUILD_BUG_ON(
                sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
 
-       eth_random_addr(node_id);
        return 0;
 }
 module_init(usbnet_init);