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>

3 files changed, 312 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);
diff --git a/net/core/dev.c b/net/core/dev.c
index 3c8073fe970a..637ea71b0a0d 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);