Re: [PATCH 1/3] net: introduce a list of device addressesdev_addr_list

[Jiri Pirko]

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.

Note: patch adding list_first_entry_rcu (currently in Ingo's tip tree) needed.

Signed-off-by: Jiri Pirko <jpirko@xxxxxxxxxx>
---
 include/linux/etherdevice.h |   24 ++++
 include/linux/netdevice.h   |   31 +++++-
 net/core/dev.c              |  263 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 316 insertions(+), 2 deletions(-)

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index a1f17ab..348a75e 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -205,4 +205,28 @@ static inline int compare_ether_header(const void *a, const void *b)
 	       (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 }
 
+/**
+ * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
+ * @dev: Pointer to a device structure
+ * @addr: Pointer to a six-byte array containing the Ethernet address
+ *
+ * Compare passed address with all addresses of the device. Return true if the
+ * address if one of the device addresses.
+ */
+static inline bool is_etherdev_addr(const struct net_device *dev,
+				    const u8 *addr)
+{
+	struct netdev_hw_addr *ha;
+	int res = 1;
+
+	rcu_read_lock();
+	for_each_dev_addr(dev, ha) {
+		res = compare_ether_addr(addr, ha->addr);
+		if (!res)
+			break;
+	}
+	rcu_read_unlock();
+	return !res;
+}
+
 #endif	/* _LINUX_ETHERDEVICE_H */
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2e7783f..77abfdf 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -210,6 +210,12 @@ struct dev_addr_list
 #define dmi_users	da_users
 #define dmi_gusers	da_gusers
 
+struct netdev_hw_addr {
+	struct list_head	list;
+	unsigned char		addr[MAX_ADDR_LEN];
+	int			refcount;
+};
+
 struct hh_cache
 {
 	struct hh_cache *hh_next;	/* Next entry			     */
@@ -776,8 +782,11 @@ struct net_device
  */
 	unsigned long		last_rx;	/* Time of last Rx	*/
 	/* Interface address info used in eth_type_trans() */
-	unsigned char		dev_addr[MAX_ADDR_LEN];	/* hw address, (before bcast
-							   because most packets are unicast) */
+	unsigned char		*dev_addr;	/* hw address, (before bcast
+						   because most packets are
+						   unicast) */
+
+	struct list_head	dev_addr_list; /* list of device hw addresses */
 
 	unsigned char		broadcast[MAX_ADDR_LEN];	/* hw bcast add	*/
 
@@ -1778,6 +1787,13 @@ static inline void netif_addr_unlock_bh(struct net_device *dev)
 	spin_unlock_bh(&dev->addr_list_lock);
 }
 
+/*
+ * dev_addr_list walker. Should be used only for read access. Call with
+ * rcu_read_lock held.
+ */
+#define for_each_dev_addr(dev, ha) \
+		list_for_each_entry_rcu(ha, &dev->dev_addr_list, list)
+
 /* These functions live elsewhere (drivers/net/net_init.c, but related) */
 
 extern void		ether_setup(struct net_device *dev);
@@ -1790,6 +1806,17 @@ extern struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 	alloc_netdev_mq(sizeof_priv, name, setup, 1)
 extern int		register_netdev(struct net_device *dev);
 extern void		unregister_netdev(struct net_device *dev);
+
+/* Functions used for device addresses handling */
+extern int		dev_addr_add(struct net_device *dev,
+				     unsigned char *addr);
+extern int		dev_addr_del(struct net_device *dev,
+				     unsigned char *addr);
+extern int		dev_addr_add_multiple(struct net_device *to_dev,
+					      struct net_device *from_dev);
+extern int		dev_addr_del_multiple(struct net_device *to_dev,
+					      struct net_device *from_dev);
+
 /* Functions used for secondary unicast and multicast support */
 extern void		dev_set_rx_mode(struct net_device *dev);
 extern void		__dev_set_rx_mode(struct net_device *dev);
diff --git a/net/core/dev.c b/net/core/dev.c
index 91d792d..04cddbb 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3437,6 +3437,262 @@ void dev_set_rx_mode(struct net_device *dev)
 	netif_addr_unlock_bh(dev);
 }
 
+/* hw addresses list handling functions */
+
+static int __hw_addr_add_ii(struct list_head *list, unsigned char *addr,
+			    int addr_len, int ignore_index)
+{
+	struct netdev_hw_addr *ha;
+	int i = 0;
+
+	if (addr_len > MAX_ADDR_LEN)
+		return -EINVAL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ha, list, list) {
+		if (i++ != ignore_index &&
+		    !memcmp(ha->addr, addr, addr_len)) {
+			ha->refcount++;
+			rcu_read_unlock();
+			return 0;
+		}
+	}
+	rcu_read_unlock();
+
+	ha = kzalloc(sizeof(*ha), GFP_ATOMIC);
+	if (!ha)
+		return -ENOMEM;
+	memcpy(ha->addr, addr, addr_len);
+	ha->refcount = 1;
+	list_add_tail_rcu(&ha->list, list);
+	return 0;
+}
+
+static int __hw_addr_add(struct list_head *list, unsigned char *addr,
+				int addr_len)
+{
+	return __hw_addr_add_ii(list, addr, addr_len, -1);
+}
+
+static int __hw_addr_del_ii(struct list_head *list, unsigned char *addr,
+			    int addr_len, 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)) {
+			if (--ha->refcount)
+				return 0;
+			list_del_rcu(&ha->list);
+			synchronize_rcu();
+			kfree(ha);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+static int __hw_addr_del(struct list_head *list, unsigned char *addr,
+				int addr_len)
+{
+	return __hw_addr_del_ii(list, addr, addr_len, -1);
+}
+
+static int __hw_addr_add_multiple_ii(struct list_head *to_list,
+				     struct list_head *from_list,
+				     int addr_len, int ignore_index)
+{
+	int err = 0;
+	struct netdev_hw_addr *ha, *ha2;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ha, from_list, list) {
+		err = __hw_addr_add_ii(to_list, ha->addr, addr_len, 0);
+		if (err)
+			goto unroll;
+	}
+	goto unlock;
+unroll:
+	list_for_each_entry_rcu(ha2, from_list, list) {
+		if (ha2 == ha)
+			break;
+		__hw_addr_del_ii(to_list, ha2->addr, addr_len, 0);
+	}
+unlock:
+	rcu_read_unlock();
+	return err;
+}
+
+static int __hw_addr_add_multiple(struct list_head *to_list,
+					 struct list_head *from_list,
+					 int addr_len)
+{
+	return __hw_addr_add_multiple_ii(to_list, from_list, addr_len, -1);
+}
+
+static void __hw_addr_del_multiple_ii(struct list_head *to_list,
+				      struct list_head *from_list,
+				      int addr_len, int ignore_index)
+{
+	struct netdev_hw_addr *ha;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ha, from_list, list) {
+		__hw_addr_del_ii(to_list, ha->addr, addr_len, 0);
+	}
+	rcu_read_unlock();
+}
+
+static void __hw_addr_del_multiple(struct list_head *to_list,
+					 struct list_head *from_list,
+					 int addr_len)
+{
+	__hw_addr_del_multiple_ii(to_list, from_list, addr_len, -1);
+}
+
+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);
+		synchronize_rcu();
+		kfree(ha);
+	}
+}
+
+/* Device addresses handling functions */
+
+static void dev_addr_flush(struct net_device *dev)
+{
+	__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;
+
+	INIT_LIST_HEAD(&dev->dev_addr_list);
+	memset(addr, 0, sizeof(*addr));
+	err = __hw_addr_add(&dev->dev_addr_list, addr, sizeof(*addr));
+	if (!err) {
+		/*
+		 * Get the first (previously created) address from the list
+		 * and set dev_addr pointer to this location.
+		 */
+		rcu_read_lock();
+		ha = list_first_entry_rcu(&dev->dev_addr_list,
+					  struct netdev_hw_addr, list);
+		dev->dev_addr = ha->addr;
+		rcu_read_unlock();
+	}
+	return err;
+}
+
+/**
+ *	dev_addr_add	- Add a device address
+ *	@dev: device
+ *	@addr: address to add
+ *
+ *	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)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	err = __hw_addr_add_ii(&dev->dev_addr_list, addr, dev->addr_len, 0);
+	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
+ *
+ *	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)
+{
+	int err;
+
+	ASSERT_RTNL();
+
+	err = __hw_addr_del_ii(&dev->dev_addr_list, addr, dev->addr_len, 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
+ *
+ *	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)
+{
+	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, 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
+ *
+ *	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)
+{
+	ASSERT_RTNL();
+
+	if (from_dev->addr_len != to_dev->addr_len)
+		return -EINVAL;
+	__hw_addr_add_multiple_ii(&to_dev->dev_addr_list,
+				  &from_dev->dev_addr_list,
+				  to_dev->addr_len, 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)
 {
@@ -4257,6 +4513,9 @@ static void rollback_registered(struct net_device *dev)
 	 */
 	dev_addr_discard(dev);
 
+	/* Flush device addresses */
+	dev_addr_flush(dev);
+
 	if (dev->netdev_ops->ndo_uninit)
 		dev->netdev_ops->ndo_uninit(dev);
 
@@ -4779,6 +5038,7 @@ 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);
@@ -4965,6 +5225,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	 */
 	dev_addr_discard(dev);
 
+	/* Flush device addresses */
+	dev_addr_flush(dev);
+
 	netdev_unregister_kobject(dev);
 
 	/* Actually switch the network namespace */
-- 
1.6.0.6

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