[PATCH 1/3] net: introduce a list of device addresses dev_addr_list (v2)

Jiri Pirko
2009-04-15T18:04:20Z

changes against last patch version:
-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 | 32 +++++-
net/core/dev.c | 271 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 328 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 2e7783f..89ad6d2 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -210,6 +210,13 @@ 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 rcu_head rcu_head;
+};
+
struct hh_cache
{
struct hh_cache *hh_next; /* Next entry */
@@ -776,8 +783,11 @@ 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 +1788,13 @@ 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 +1807,17 @@ 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..961be4f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3437,6 +3437,270 @@ 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(max(sizeof(*ha), L1_CACHE_BYTES), 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 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, 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);
+ call_rcu(&ha->rcu_head, ha_rcu_free);
+ 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);
+ call_rcu(&ha->rcu_head, ha_rcu_free);
+ }
+}
+
+/* Device addresses handling functions */
+
+static void dev_addr_flush(struct net_device *dev)
+{
+ ASSERT_RTNL();
+
+ __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;
+
+ ASSERT_RTNL();
+
+ 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.
+ */
+ 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
+ *
+ * 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 +4521,9 @@ 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 +5046,7 @@ 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 +5233,9 @@ 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