net: create netdev->dev_addr assignment helpers

Recent work on converting address list to a tree made it obvious
we need an abstraction around writing netdev->dev_addr. Without
such abstraction updating the main device address is invisible
to the core.

Introduce a number of helpers which for now just wrap memcpy()
but in the future can make necessary changes to the address
tree.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/etherdevice.h

@@ -299,6 +299,18 @@ static inline void ether_addr_copy(u8 *dst, const u8 *src)
 #endif
 }
 
+/**
+ * eth_hw_addr_set - Assign Ethernet address to a net_device
+ * @dev: pointer to net_device structure
+ * @addr: address to assign
+ *
+ * Assign given address to the net_device, addr_assign_type is not changed.
+ */
+static inline void eth_hw_addr_set(struct net_device *dev, const u8 *addr)
+{
+	ether_addr_copy(dev->dev_addr, addr);
+}
+
 /**
  * eth_hw_addr_inherit - Copy dev_addr from another net_device
  * @dst: pointer to net_device to copy dev_addr to

include/linux/netdevice.h

@@ -4641,6 +4641,24 @@ void __hw_addr_unsync_dev(struct netdev_hw_addr_list *list,
 void __hw_addr_init(struct netdev_hw_addr_list *list);
 
 /* Functions used for device addresses handling */
+static inline void
+__dev_addr_set(struct net_device *dev, const u8 *addr, size_t len)
+{
+	memcpy(dev->dev_addr, addr, len);
+}
+
+static inline void dev_addr_set(struct net_device *dev, const u8 *addr)
+{
+	__dev_addr_set(dev, addr, dev->addr_len);
+}
+
+static inline void
+dev_addr_mod(struct net_device *dev, unsigned int offset,
+	     const u8 *addr, size_t len)
+{
+	memcpy(&dev->dev_addr[offset], addr, len);
+}
+
 int dev_addr_add(struct net_device *dev, const unsigned char *addr,
 		 unsigned char addr_type);
 int dev_addr_del(struct net_device *dev, const unsigned char *addr,