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>

2 files changed, 62 insertions, 2 deletions

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index a1f17abba7dc..3d7a6687d247 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 ff42aba403c5..02882e2ebd49 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                        */
@@ -784,8 +794,11 @@ 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 */
 
@@ -1791,6 +1804,13 @@ 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);
@@ -1803,6 +1823,19 @@ 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);