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Subject[PATCH] 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>
---
include/linux/etherdevice.h | 27 +++++
include/linux/netdevice.h | 37 ++++++-
net/core/dev.c | 250 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 312 insertions(+), 2 deletions(-)

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index a1f17ab..3d7a668 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -182,6 +182,33 @@ static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2],
return compare_ether_addr(addr1, addr2);
#endif
}
+
+/**
+ * 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.
+ *
+ * Note that this function calls compare_ether_addr_64bits() so take care of
+ * the right padding.
+ */
+static inline bool is_etherdev_addr(const struct net_device *dev,
+ const u8 addr[6 + 2])
+{
+ struct netdev_hw_addr *ha;
+ int res = 1;
+
+ rcu_read_lock();
+ for_each_dev_addr(dev, ha) {
+ res = compare_ether_addr_64bits(addr, ha->addr);
+ if (!res)
+ break;
+ }
+ rcu_read_unlock();
+ return !res;
+}
#endif /* __KERNEL__ */

/**
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5a96a1a..a95befc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -210,6 +210,16 @@ 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];
+ unsigned char type;
+#define NETDEV_HW_ADDR_T_LAN 1
+#define NETDEV_HW_ADDR_T_SAN 2
+#define NETDEV_HW_ADDR_T_SLAVE 3
+ struct rcu_head rcu_head;
+};
+
struct hh_cache
{
struct hh_cache *hh_next; /* Next entry */
@@ -776,8 +786,11 @@ 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 +1791,13 @@ 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 +1810,19 @@ 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,
+ unsigned char addr_type);
+extern int dev_addr_del(struct net_device *dev, unsigned char *addr,
+ unsigned char addr_type);
+extern int dev_addr_add_multiple(struct net_device *to_dev,
+ struct net_device *from_dev,
+ unsigned char addr_type);
+extern int dev_addr_del_multiple(struct net_device *to_dev,
+ struct net_device *from_dev,
+ unsigned char addr_type);
+
/* 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 308a7d0..b2f752b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3443,6 +3443,252 @@ 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)
{
@@ -4785,6 +5031,7 @@ 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);
@@ -4810,6 +5057,9 @@ 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);


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