net: introduce a list of device addresses dev_addr_list (v6)

v5 -> v6 (current):
-removed so far unused static functions
-corrected dev_addr_del_multiple to call del instead of add

v4 -> v5:
-added device address type (suggested by davem)
-removed refcounting (better to have simplier code then safe potentially few
 bytes)

v3 -> v4:
-changed kzalloc to kmalloc in __hw_addr_add_ii()
-ASSERT_RTNL() avoided in dev_addr_flush() and dev_addr_init()

v2 -> v3:
-removed unnecessary rcu read locking
-moved dev_addr_flush() calling to ensure no null dereference of dev_addr

v1 -> v2:
-added forgotten ASSERT_RTNL to dev_addr_init and dev_addr_flush
-removed unnecessary rcu_read locking in dev_addr_init
-use compare_ether_addr_64bits instead of compare_ether_addr
-use L1_CACHE_BYTES as size for allocating struct netdev_hw_addr
-use call_rcu instead of rcu_synchronize
-moved is_etherdev_addr into __KERNEL__ ifdef

This patch introduces a new list in struct net_device and brings a set of
functions to handle the work with device address list. The list is a replacement
for the original dev_addr field and because in some situations there is need to
carry several device addresses with the net device. To be backward compatible,
dev_addr is made to point to the first member of the list so original drivers
sees no difference.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 250 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 3c8073f..637ea71 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3434,6 +3434,252 @@ void dev_set_rx_mode(struct net_device *dev)
 	netif_addr_unlock_bh(dev);
 }
 
+/* hw addresses list handling functions */
+
+static int __hw_addr_add(struct list_head *list, unsigned char *addr,
+			 int addr_len, unsigned char addr_type)
+{
+	struct netdev_hw_addr *ha;
+	int alloc_size;
+
+	if (addr_len > MAX_ADDR_LEN)
+		return -EINVAL;
+
+	alloc_size = sizeof(*ha);
+	if (alloc_size < L1_CACHE_BYTES)
+		alloc_size = L1_CACHE_BYTES;
+	ha = kmalloc(alloc_size, GFP_ATOMIC);
+	if (!ha)
+		return -ENOMEM;
+	memcpy(ha->addr, addr, addr_len);
+	ha->type = addr_type;
+	list_add_tail_rcu(&ha->list, list);
+	return 0;
+}
+
+static void ha_rcu_free(struct rcu_head *head)
+{
+	struct netdev_hw_addr *ha;
+
+	ha = container_of(head, struct netdev_hw_addr, rcu_head);
+	kfree(ha);
+}
+
+static int __hw_addr_del_ii(struct list_head *list, unsigned char *addr,
+			    int addr_len, unsigned char addr_type,
+			    int ignore_index)
+{
+	struct netdev_hw_addr *ha;
+	int i = 0;
+
+	list_for_each_entry(ha, list, list) {
+		if (i++ != ignore_index &&
+		    !memcmp(ha->addr, addr, addr_len) &&
+		    (ha->type == addr_type || !addr_type)) {
+			list_del_rcu(&ha->list);
+			call_rcu(&ha->rcu_head, ha_rcu_free);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+static int __hw_addr_add_multiple_ii(struct list_head *to_list,
+				     struct list_head *from_list,
+				     int addr_len, unsigned char addr_type,
+				     int ignore_index)
+{
+	int err;
+	struct netdev_hw_addr *ha, *ha2;
+	unsigned char type;
+
+	list_for_each_entry(ha, from_list, list) {
+		type = addr_type ? addr_type : ha->type;
+		err = __hw_addr_add(to_list, ha->addr, addr_len, type);
+		if (err)
+			goto unroll;
+	}
+	return 0;
+
+unroll:
+	list_for_each_entry(ha2, from_list, list) {
+		if (ha2 == ha)
+			break;
+		type = addr_type ? addr_type : ha2->type;
+		__hw_addr_del_ii(to_list, ha2->addr, addr_len, type,
+				 ignore_index);
+	}
+	return err;
+}
+
+static void __hw_addr_del_multiple_ii(struct list_head *to_list,
+				      struct list_head *from_list,
+				      int addr_len, unsigned char addr_type,
+				      int ignore_index)
+{
+	struct netdev_hw_addr *ha;
+	unsigned char type;
+
+	list_for_each_entry(ha, from_list, list) {
+		type = addr_type ? addr_type : ha->type;
+		__hw_addr_del_ii(to_list, ha->addr, addr_len, addr_type,
+				 ignore_index);
+	}
+}
+
+static void __hw_addr_flush(struct list_head *list)
+{
+	struct netdev_hw_addr *ha, *tmp;
+
+	list_for_each_entry_safe(ha, tmp, list, list) {
+		list_del_rcu(&ha->list);
+		call_rcu(&ha->rcu_head, ha_rcu_free);
+	}
+}
+
+/* Device addresses handling functions */
+
+static void dev_addr_flush(struct net_device *dev)
+{
+	/* rtnl_mutex must be held here */
+
+	__hw_addr_flush(&dev->dev_addr_list);
+	dev->dev_addr = NULL;
+}
+
+static int dev_addr_init(struct net_device *dev)
+{
+	unsigned char addr[MAX_ADDR_LEN];
+	struct netdev_hw_addr *ha;
+	int err;
+
+	/* rtnl_mutex must be held here */
+
+	INIT_LIST_HEAD(&dev->dev_addr_list);
+	memset(addr, 0, sizeof(*addr));
+	err = __hw_addr_add(&dev->dev_addr_list, addr, sizeof(*addr),
+			    NETDEV_HW_ADDR_T_LAN);
+	if (!err) {
+		/*
+		 * Get the first (previously created) address from the list
+		 * and set dev_addr pointer to this location.
+		 */
+		ha = list_first_entry(&dev->dev_addr_list,
+				      struct netdev_hw_addr, list);
+		dev->dev_addr = ha->addr;
+	}
+	return err;
+}
+
+/**
+ *	dev_addr_add	- Add a device address
+ *	@dev: device
+ *	@addr: address to add
+ *	@addr_type: address type
+ *
+ *	Add a device address to the device or increase the reference count if
+ *	it already exists.
+ *
+ *	The caller must hold the rtnl_mutex.
+ */
+int dev_addr_add(struct net_device *dev, unsigned char *addr,
+		 unsigned char addr_type)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	err = __hw_addr_add(&dev->dev_addr_list, addr, dev->addr_len,
+			    addr_type);
+	if (!err)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+	return err;
+}
+EXPORT_SYMBOL(dev_addr_add);
+
+/**
+ *	dev_addr_del	- Release a device address.
+ *	@dev: device
+ *	@addr: address to delete
+ *	@addr_type: address type
+ *
+ *	Release reference to a device address and remove it from the device
+ *	if the reference count drops to zero.
+ *
+ *	The caller must hold the rtnl_mutex.
+ */
+int dev_addr_del(struct net_device *dev, unsigned char *addr,
+		 unsigned char addr_type)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	err = __hw_addr_del_ii(&dev->dev_addr_list, addr, dev->addr_len,
+			       addr_type, 0);
+	if (!err)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+	return err;
+}
+EXPORT_SYMBOL(dev_addr_del);
+
+/**
+ *	dev_addr_add_multiple	- Add device addresses from another device
+ *	@to_dev: device to which addresses will be added
+ *	@from_dev: device from which addresses will be added
+ *	@addr_type: address type - 0 means type will be used from from_dev
+ *
+ *	Add device addresses of the one device to another.
+ **
+ *	The caller must hold the rtnl_mutex.
+ */
+int dev_addr_add_multiple(struct net_device *to_dev,
+			  struct net_device *from_dev,
+			  unsigned char addr_type)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	if (from_dev->addr_len != to_dev->addr_len)
+		return -EINVAL;
+	err = __hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
+					&from_dev->dev_addr_list,
+					to_dev->addr_len, addr_type, 0);
+	if (!err)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, to_dev);
+	return err;
+}
+EXPORT_SYMBOL(dev_addr_add_multiple);
+
+/**
+ *	dev_addr_del_multiple	- Delete device addresses by another device
+ *	@to_dev: device where the addresses will be deleted
+ *	@from_dev: device by which addresses the addresses will be deleted
+ *	@addr_type: address type - 0 means type will used from from_dev
+ *
+ *	Deletes addresses in to device by the list of addresses in from device.
+ *
+ *	The caller must hold the rtnl_mutex.
+ */
+int dev_addr_del_multiple(struct net_device *to_dev,
+			  struct net_device *from_dev,
+			  unsigned char addr_type)
+{
+	ASSERT_RTNL();
+
+	if (from_dev->addr_len != to_dev->addr_len)
+		return -EINVAL;
+	__hw_addr_del_multiple_ii(&to_dev->dev_addr_list,
+				  &from_dev->dev_addr_list,
+				  to_dev->addr_len, addr_type, 0);
+	call_netdevice_notifiers(NETDEV_CHANGEADDR, to_dev);
+	return 0;
+}
+EXPORT_SYMBOL(dev_addr_del_multiple);
+
+/* unicast and multicast addresses handling functions */
+
 int __dev_addr_delete(struct dev_addr_list **list, int *count,
 		      void *addr, int alen, int glbl)
 {
@@ -4776,6 +5022,7 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 
 	dev->gso_max_size = GSO_MAX_SIZE;
 
+	dev_addr_init(dev);
 	netdev_init_queues(dev);
 
 	INIT_LIST_HEAD(&dev->napi_list);
@@ -4801,6 +5048,9 @@ void free_netdev(struct net_device *dev)
 
 	kfree(dev->_tx);
 
+	/* Flush device addresses */
+	dev_addr_flush(dev);
+
 	list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
 		netif_napi_del(p);