/*
   * net/core/dev_addr_lists.c - Functions for handling net device lists
   * Copyright (c) 2010 Jiri Pirko <jpirko@redhat.com>
   *
   * This file contains functions for working with unicast, multicast and device
   * addresses lists.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <linux/netdevice.h>
  #include <linux/rtnetlink.h>

  #include <linux/export.h>

  #include <linux/list.h>
  
  /*
   * General list handling functions
   */

  static int __hw_addr_create_ex(struct netdev_hw_addr_list *list,

  			       const unsigned char *addr, int addr_len,

  			       unsigned char addr_type, bool global,
  			       bool sync)

  {
  	struct netdev_hw_addr *ha;
  	int alloc_size;
  
  	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;
  	ha->refcount = 1;
  	ha->global_use = global;

  	ha->synced = sync ? 1 : 0;

  	ha->sync_cnt = 0;

  	list_add_tail_rcu(&ha->list, &list->list);
  	list->count++;
  
  	return 0;
  }

  static int __hw_addr_add_ex(struct netdev_hw_addr_list *list,

  			    const unsigned char *addr, int addr_len,

  			    unsigned char addr_type, bool global, bool sync,
  			    int sync_count)

  {
  	struct netdev_hw_addr *ha;

  
  	if (addr_len > MAX_ADDR_LEN)
  		return -EINVAL;
  
  	list_for_each_entry(ha, &list->list, list) {

  		if (ha->type == addr_type &&
  		    !memcmp(ha->addr, addr, addr_len)) {

  			if (global) {
  				/* check if addr is already used as global */
  				if (ha->global_use)
  					return 0;
  				else
  					ha->global_use = true;
  			}

  			if (sync) {

  				if (ha->synced && sync_count)

  					return -EEXIST;

  				else

  					ha->synced++;

  			}

  			ha->refcount++;
  			return 0;
  		}
  	}

  	return __hw_addr_create_ex(list, addr, addr_len, addr_type, global,
  				   sync);

  }

  static int __hw_addr_add(struct netdev_hw_addr_list *list,
  			 const unsigned char *addr, int addr_len,
  			 unsigned char addr_type)

  {

  	return __hw_addr_add_ex(list, addr, addr_len, addr_type, false, false,
  				0);

  }
  
  static int __hw_addr_del_entry(struct netdev_hw_addr_list *list,
  			       struct netdev_hw_addr *ha, bool global,
  			       bool sync)
  {
  	if (global && !ha->global_use)
  		return -ENOENT;
  
  	if (sync && !ha->synced)
  		return -ENOENT;
  
  	if (global)
  		ha->global_use = false;
  
  	if (sync)

  		ha->synced--;

  
  	if (--ha->refcount)
  		return 0;
  	list_del_rcu(&ha->list);
  	kfree_rcu(ha, rcu_head);
  	list->count--;
  	return 0;

  }

  static int __hw_addr_del_ex(struct netdev_hw_addr_list *list,

  			    const unsigned char *addr, int addr_len,

  			    unsigned char addr_type, bool global, bool sync)

  {
  	struct netdev_hw_addr *ha;
  
  	list_for_each_entry(ha, &list->list, list) {
  		if (!memcmp(ha->addr, addr, addr_len) &&

  		    (ha->type == addr_type || !addr_type))
  			return __hw_addr_del_entry(list, ha, global, sync);

  	}
  	return -ENOENT;
  }

  static int __hw_addr_del(struct netdev_hw_addr_list *list,
  			 const unsigned char *addr, int addr_len,
  			 unsigned char addr_type)

  {

  	return __hw_addr_del_ex(list, addr, addr_len, addr_type, false, false);
  }
  
  static int __hw_addr_sync_one(struct netdev_hw_addr_list *to_list,
  			       struct netdev_hw_addr *ha,
  			       int addr_len)
  {
  	int err;
  
  	err = __hw_addr_add_ex(to_list, ha->addr, addr_len, ha->type,

  			       false, true, ha->sync_cnt);

  	if (err && err != -EEXIST)

  		return err;

  
  	if (!err) {
  		ha->sync_cnt++;
  		ha->refcount++;
  	}

  
  	return 0;
  }
  
  static void __hw_addr_unsync_one(struct netdev_hw_addr_list *to_list,
  				 struct netdev_hw_addr_list *from_list,
  				 struct netdev_hw_addr *ha,
  				 int addr_len)
  {
  	int err;
  
  	err = __hw_addr_del_ex(to_list, ha->addr, addr_len, ha->type,
  			       false, true);
  	if (err)
  		return;
  	ha->sync_cnt--;

  	/* address on from list is not marked synced */
  	__hw_addr_del_entry(from_list, ha, false, false);

  }
  
  static int __hw_addr_sync_multiple(struct netdev_hw_addr_list *to_list,
  				   struct netdev_hw_addr_list *from_list,
  				   int addr_len)
  {
  	int err = 0;
  	struct netdev_hw_addr *ha, *tmp;
  
  	list_for_each_entry_safe(ha, tmp, &from_list->list, list) {
  		if (ha->sync_cnt == ha->refcount) {
  			__hw_addr_unsync_one(to_list, from_list, ha, addr_len);
  		} else {
  			err = __hw_addr_sync_one(to_list, ha, addr_len);
  			if (err)
  				break;
  		}
  	}
  	return err;

  }

  /* This function only works where there is a strict 1-1 relationship
   * between source and destionation of they synch. If you ever need to
   * sync addresses to more then 1 destination, you need to use
   * __hw_addr_sync_multiple().
   */

  int __hw_addr_sync(struct netdev_hw_addr_list *to_list,
  		   struct netdev_hw_addr_list *from_list,
  		   int addr_len)

  {
  	int err = 0;
  	struct netdev_hw_addr *ha, *tmp;
  
  	list_for_each_entry_safe(ha, tmp, &from_list->list, list) {

  		if (!ha->sync_cnt) {
  			err = __hw_addr_sync_one(to_list, ha, addr_len);

  			if (err)
  				break;

  		} else if (ha->refcount == 1)
  			__hw_addr_unsync_one(to_list, from_list, ha, addr_len);

  	}
  	return err;
  }

  EXPORT_SYMBOL(__hw_addr_sync);

  void __hw_addr_unsync(struct netdev_hw_addr_list *to_list,
  		      struct netdev_hw_addr_list *from_list,
  		      int addr_len)

  {
  	struct netdev_hw_addr *ha, *tmp;
  
  	list_for_each_entry_safe(ha, tmp, &from_list->list, list) {

  		if (ha->sync_cnt)
  			__hw_addr_unsync_one(to_list, from_list, ha, addr_len);

  	}
  }

  EXPORT_SYMBOL(__hw_addr_unsync);

  /**
   *  __hw_addr_sync_dev - Synchonize device's multicast list
   *  @list: address list to syncronize
   *  @dev:  device to sync
   *  @sync: function to call if address should be added
   *  @unsync: function to call if address should be removed
   *
   *  This funciton is intended to be called from the ndo_set_rx_mode
   *  function of devices that require explicit address add/remove
   *  notifications.  The unsync function may be NULL in which case
   *  the addresses requiring removal will simply be removed without
   *  any notification to the device.
   **/
  int __hw_addr_sync_dev(struct netdev_hw_addr_list *list,
  		       struct net_device *dev,
  		       int (*sync)(struct net_device *, const unsigned char *),
  		       int (*unsync)(struct net_device *,
  				     const unsigned char *))
  {
  	struct netdev_hw_addr *ha, *tmp;
  	int err;
  
  	/* first go through and flush out any stale entries */
  	list_for_each_entry_safe(ha, tmp, &list->list, list) {
  		if (!ha->sync_cnt || ha->refcount != 1)
  			continue;
  
  		/* if unsync is defined and fails defer unsyncing address */
  		if (unsync && unsync(dev, ha->addr))
  			continue;
  
  		ha->sync_cnt--;
  		__hw_addr_del_entry(list, ha, false, false);
  	}
  
  	/* go through and sync new entries to the list */
  	list_for_each_entry_safe(ha, tmp, &list->list, list) {
  		if (ha->sync_cnt)
  			continue;
  
  		err = sync(dev, ha->addr);
  		if (err)
  			return err;
  
  		ha->sync_cnt++;
  		ha->refcount++;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL(__hw_addr_sync_dev);
  
  /**

   *  __hw_addr_unsync_dev - Remove synchronized addresses from device
   *  @list: address list to remove synchronized addresses from

   *  @dev:  device to sync
   *  @unsync: function to call if address should be removed
   *
   *  Remove all addresses that were added to the device by __hw_addr_sync_dev().
   *  This function is intended to be called from the ndo_stop or ndo_open
   *  functions on devices that require explicit address add/remove
   *  notifications.  If the unsync function pointer is NULL then this function
   *  can be used to just reset the sync_cnt for the addresses in the list.
   **/
  void __hw_addr_unsync_dev(struct netdev_hw_addr_list *list,
  			  struct net_device *dev,
  			  int (*unsync)(struct net_device *,
  					const unsigned char *))
  {
  	struct netdev_hw_addr *ha, *tmp;
  
  	list_for_each_entry_safe(ha, tmp, &list->list, list) {
  		if (!ha->sync_cnt)
  			continue;
  
  		/* if unsync is defined and fails defer unsyncing address */
  		if (unsync && unsync(dev, ha->addr))
  			continue;
  
  		ha->sync_cnt--;
  		__hw_addr_del_entry(list, ha, false, false);
  	}
  }
  EXPORT_SYMBOL(__hw_addr_unsync_dev);

  static void __hw_addr_flush(struct netdev_hw_addr_list *list)

  {
  	struct netdev_hw_addr *ha, *tmp;
  
  	list_for_each_entry_safe(ha, tmp, &list->list, list) {
  		list_del_rcu(&ha->list);

  		kfree_rcu(ha, rcu_head);

  	}
  	list->count = 0;
  }

  void __hw_addr_init(struct netdev_hw_addr_list *list)

  {
  	INIT_LIST_HEAD(&list->list);
  	list->count = 0;
  }

  EXPORT_SYMBOL(__hw_addr_init);

  
  /*
   * Device addresses handling functions
   */
  
  /**
   *	dev_addr_flush - Flush device address list
   *	@dev: device
   *
   *	Flush device address list and reset ->dev_addr.
   *
   *	The caller must hold the rtnl_mutex.
   */
  void dev_addr_flush(struct net_device *dev)
  {
  	/* rtnl_mutex must be held here */
  
  	__hw_addr_flush(&dev->dev_addrs);
  	dev->dev_addr = NULL;
  }
  EXPORT_SYMBOL(dev_addr_flush);
  
  /**
   *	dev_addr_init - Init device address list
   *	@dev: device
   *
   *	Init device address list and create the first element,
   *	used by ->dev_addr.
   *
   *	The caller must hold the rtnl_mutex.
   */
  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 */
  
  	__hw_addr_init(&dev->dev_addrs);
  	memset(addr, 0, sizeof(addr));
  	err = __hw_addr_add(&dev->dev_addrs, 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_addrs.list,
  				      struct netdev_hw_addr, list);
  		dev->dev_addr = ha->addr;
  	}
  	return err;
  }
  EXPORT_SYMBOL(dev_addr_init);
  
  /**
   *	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, const unsigned char *addr,

  		 unsigned char addr_type)
  {
  	int err;
  
  	ASSERT_RTNL();
  
  	err = __hw_addr_add(&dev->dev_addrs, 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, const unsigned char *addr,

  		 unsigned char addr_type)
  {
  	int err;
  	struct netdev_hw_addr *ha;
  
  	ASSERT_RTNL();
  
  	/*
  	 * We can not remove the first address from the list because
  	 * dev->dev_addr points to that.
  	 */
  	ha = list_first_entry(&dev->dev_addrs.list,
  			      struct netdev_hw_addr, list);

  	if (!memcmp(ha->addr, addr, dev->addr_len) &&
  	    ha->type == addr_type && ha->refcount == 1)

  		return -ENOENT;
  
  	err = __hw_addr_del(&dev->dev_addrs, addr, dev->addr_len,
  			    addr_type);
  	if (!err)
  		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
  	return err;
  }
  EXPORT_SYMBOL(dev_addr_del);

  /*
   * Unicast list handling functions
   */
  
  /**

   *	dev_uc_add_excl - Add a global secondary unicast address
   *	@dev: device
   *	@addr: address to add
   */

  int dev_uc_add_excl(struct net_device *dev, const unsigned char *addr)

  {
  	struct netdev_hw_addr *ha;
  	int err;
  
  	netif_addr_lock_bh(dev);
  	list_for_each_entry(ha, &dev->uc.list, list) {
  		if (!memcmp(ha->addr, addr, dev->addr_len) &&
  		    ha->type == NETDEV_HW_ADDR_T_UNICAST) {
  			err = -EEXIST;
  			goto out;
  		}
  	}
  	err = __hw_addr_create_ex(&dev->uc, addr, dev->addr_len,

  				  NETDEV_HW_ADDR_T_UNICAST, true, false);

  	if (!err)
  		__dev_set_rx_mode(dev);
  out:
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  EXPORT_SYMBOL(dev_uc_add_excl);
  
  /**

   *	dev_uc_add - Add a secondary unicast address
   *	@dev: device
   *	@addr: address to add
   *
   *	Add a secondary unicast address to the device or increase
   *	the reference count if it already exists.
   */

  int dev_uc_add(struct net_device *dev, const unsigned char *addr)

  {
  	int err;
  
  	netif_addr_lock_bh(dev);
  	err = __hw_addr_add(&dev->uc, addr, dev->addr_len,
  			    NETDEV_HW_ADDR_T_UNICAST);
  	if (!err)
  		__dev_set_rx_mode(dev);
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  EXPORT_SYMBOL(dev_uc_add);
  
  /**
   *	dev_uc_del - Release secondary unicast address.
   *	@dev: device
   *	@addr: address to delete
   *
   *	Release reference to a secondary unicast address and remove it
   *	from the device if the reference count drops to zero.
   */

  int dev_uc_del(struct net_device *dev, const unsigned char *addr)

  {
  	int err;
  
  	netif_addr_lock_bh(dev);
  	err = __hw_addr_del(&dev->uc, addr, dev->addr_len,
  			    NETDEV_HW_ADDR_T_UNICAST);
  	if (!err)
  		__dev_set_rx_mode(dev);
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  EXPORT_SYMBOL(dev_uc_del);
  
  /**
   *	dev_uc_sync - Synchronize device's unicast list to another device
   *	@to: destination device
   *	@from: source device
   *
   *	Add newly added addresses to the destination device and release
   *	addresses that have no users left. The source device must be

   *	locked by netif_addr_lock_bh.

   *
   *	This function is intended to be called from the dev->set_rx_mode

   *	function of layered software devices.  This function assumes that
   *	addresses will only ever be synced to the @to devices and no other.

   */
  int dev_uc_sync(struct net_device *to, struct net_device *from)
  {
  	int err = 0;
  
  	if (to->addr_len != from->addr_len)
  		return -EINVAL;

  	netif_addr_lock_nested(to);

  	err = __hw_addr_sync(&to->uc, &from->uc, to->addr_len);
  	if (!err)
  		__dev_set_rx_mode(to);

  	netif_addr_unlock(to);

  	return err;
  }
  EXPORT_SYMBOL(dev_uc_sync);
  
  /**

   *	dev_uc_sync_multiple - Synchronize device's unicast list to another
   *	device, but allow for multiple calls to sync to multiple devices.
   *	@to: destination device
   *	@from: source device
   *
   *	Add newly added addresses to the destination device and release
   *	addresses that have been deleted from the source. The source device
   *	must be locked by netif_addr_lock_bh.
   *
   *	This function is intended to be called from the dev->set_rx_mode
   *	function of layered software devices.  It allows for a single source
   *	device to be synced to multiple destination devices.
   */
  int dev_uc_sync_multiple(struct net_device *to, struct net_device *from)
  {
  	int err = 0;
  
  	if (to->addr_len != from->addr_len)
  		return -EINVAL;
  
  	netif_addr_lock_nested(to);
  	err = __hw_addr_sync_multiple(&to->uc, &from->uc, to->addr_len);
  	if (!err)
  		__dev_set_rx_mode(to);
  	netif_addr_unlock(to);
  	return err;
  }
  EXPORT_SYMBOL(dev_uc_sync_multiple);
  
  /**

   *	dev_uc_unsync - Remove synchronized addresses from the destination device
   *	@to: destination device
   *	@from: source device
   *
   *	Remove all addresses that were added to the destination device by
   *	dev_uc_sync(). This function is intended to be called from the
   *	dev->stop function of layered software devices.
   */
  void dev_uc_unsync(struct net_device *to, struct net_device *from)
  {
  	if (to->addr_len != from->addr_len)
  		return;
  
  	netif_addr_lock_bh(from);

  	netif_addr_lock_nested(to);

  	__hw_addr_unsync(&to->uc, &from->uc, to->addr_len);
  	__dev_set_rx_mode(to);
  	netif_addr_unlock(to);
  	netif_addr_unlock_bh(from);
  }
  EXPORT_SYMBOL(dev_uc_unsync);
  
  /**
   *	dev_uc_flush - Flush unicast addresses
   *	@dev: device
   *
   *	Flush unicast addresses.
   */
  void dev_uc_flush(struct net_device *dev)
  {
  	netif_addr_lock_bh(dev);
  	__hw_addr_flush(&dev->uc);
  	netif_addr_unlock_bh(dev);
  }
  EXPORT_SYMBOL(dev_uc_flush);
  
  /**
   *	dev_uc_flush - Init unicast address list
   *	@dev: device
   *
   *	Init unicast address list.
   */
  void dev_uc_init(struct net_device *dev)
  {
  	__hw_addr_init(&dev->uc);
  }
  EXPORT_SYMBOL(dev_uc_init);
  
  /*
   * Multicast list handling functions
   */

  /**
   *	dev_mc_add_excl - Add a global secondary multicast address
   *	@dev: device
   *	@addr: address to add
   */

  int dev_mc_add_excl(struct net_device *dev, const unsigned char *addr)

  {
  	struct netdev_hw_addr *ha;
  	int err;
  
  	netif_addr_lock_bh(dev);
  	list_for_each_entry(ha, &dev->mc.list, list) {
  		if (!memcmp(ha->addr, addr, dev->addr_len) &&
  		    ha->type == NETDEV_HW_ADDR_T_MULTICAST) {
  			err = -EEXIST;
  			goto out;
  		}
  	}
  	err = __hw_addr_create_ex(&dev->mc, addr, dev->addr_len,

  				  NETDEV_HW_ADDR_T_MULTICAST, true, false);

  	if (!err)
  		__dev_set_rx_mode(dev);
  out:
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  EXPORT_SYMBOL(dev_mc_add_excl);

  static int __dev_mc_add(struct net_device *dev, const unsigned char *addr,

  			bool global)
  {
  	int err;
  
  	netif_addr_lock_bh(dev);
  	err = __hw_addr_add_ex(&dev->mc, addr, dev->addr_len,

  			       NETDEV_HW_ADDR_T_MULTICAST, global, false, 0);

  	if (!err)
  		__dev_set_rx_mode(dev);
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  /**
   *	dev_mc_add - Add a multicast address
   *	@dev: device
   *	@addr: address to add
   *
   *	Add a multicast address to the device or increase
   *	the reference count if it already exists.
   */

  int dev_mc_add(struct net_device *dev, const unsigned char *addr)

  {
  	return __dev_mc_add(dev, addr, false);
  }
  EXPORT_SYMBOL(dev_mc_add);
  
  /**
   *	dev_mc_add_global - Add a global multicast address
   *	@dev: device
   *	@addr: address to add
   *
   *	Add a global multicast address to the device.
   */

  int dev_mc_add_global(struct net_device *dev, const unsigned char *addr)

  {
  	return __dev_mc_add(dev, addr, true);
  }
  EXPORT_SYMBOL(dev_mc_add_global);

  static int __dev_mc_del(struct net_device *dev, const unsigned char *addr,

  			bool global)
  {
  	int err;
  
  	netif_addr_lock_bh(dev);
  	err = __hw_addr_del_ex(&dev->mc, addr, dev->addr_len,

  			       NETDEV_HW_ADDR_T_MULTICAST, global, false);

  	if (!err)
  		__dev_set_rx_mode(dev);
  	netif_addr_unlock_bh(dev);
  	return err;
  }
  
  /**
   *	dev_mc_del - Delete a multicast address.
   *	@dev: device
   *	@addr: address to delete
   *
   *	Release reference to a multicast address and remove it
   *	from the device if the reference count drops to zero.
   */

  int dev_mc_del(struct net_device *dev, const unsigned char *addr)

  {
  	return __dev_mc_del(dev, addr, false);
  }
  EXPORT_SYMBOL(dev_mc_del);
  
  /**
   *	dev_mc_del_global - Delete a global multicast address.
   *	@dev: device
   *	@addr: address to delete
   *
   *	Release reference to a multicast address and remove it
   *	from the device if the reference count drops to zero.
   */

  int dev_mc_del_global(struct net_device *dev, const unsigned char *addr)

  {
  	return __dev_mc_del(dev, addr, true);
  }
  EXPORT_SYMBOL(dev_mc_del_global);
  
  /**

   *	dev_mc_sync - Synchronize device's multicast list to another device

   *	@to: destination device
   *	@from: source device
   *
   *	Add newly added addresses to the destination device and release
   *	addresses that have no users left. The source device must be

   *	locked by netif_addr_lock_bh.

   *

   *	This function is intended to be called from the ndo_set_rx_mode
   *	function of layered software devices.

   */
  int dev_mc_sync(struct net_device *to, struct net_device *from)
  {
  	int err = 0;
  
  	if (to->addr_len != from->addr_len)
  		return -EINVAL;

  	netif_addr_lock_nested(to);

  	err = __hw_addr_sync(&to->mc, &from->mc, to->addr_len);
  	if (!err)
  		__dev_set_rx_mode(to);

  	netif_addr_unlock(to);

  	return err;
  }
  EXPORT_SYMBOL(dev_mc_sync);
  
  /**

   *	dev_mc_sync_multiple - Synchronize device's multicast list to another

   *	device, but allow for multiple calls to sync to multiple devices.
   *	@to: destination device
   *	@from: source device
   *
   *	Add newly added addresses to the destination device and release
   *	addresses that have no users left. The source device must be
   *	locked by netif_addr_lock_bh.
   *
   *	This function is intended to be called from the ndo_set_rx_mode
   *	function of layered software devices.  It allows for a single
   *	source device to be synced to multiple destination devices.
   */
  int dev_mc_sync_multiple(struct net_device *to, struct net_device *from)
  {
  	int err = 0;
  
  	if (to->addr_len != from->addr_len)
  		return -EINVAL;
  
  	netif_addr_lock_nested(to);

  	err = __hw_addr_sync_multiple(&to->mc, &from->mc, to->addr_len);

  	if (!err)
  		__dev_set_rx_mode(to);
  	netif_addr_unlock(to);
  	return err;
  }
  EXPORT_SYMBOL(dev_mc_sync_multiple);
  
  /**

   *	dev_mc_unsync - Remove synchronized addresses from the destination device
   *	@to: destination device
   *	@from: source device
   *
   *	Remove all addresses that were added to the destination device by
   *	dev_mc_sync(). This function is intended to be called from the
   *	dev->stop function of layered software devices.
   */
  void dev_mc_unsync(struct net_device *to, struct net_device *from)
  {
  	if (to->addr_len != from->addr_len)
  		return;
  
  	netif_addr_lock_bh(from);

  	netif_addr_lock_nested(to);

  	__hw_addr_unsync(&to->mc, &from->mc, to->addr_len);
  	__dev_set_rx_mode(to);
  	netif_addr_unlock(to);
  	netif_addr_unlock_bh(from);
  }
  EXPORT_SYMBOL(dev_mc_unsync);
  
  /**
   *	dev_mc_flush - Flush multicast addresses
   *	@dev: device
   *
   *	Flush multicast addresses.
   */
  void dev_mc_flush(struct net_device *dev)
  {
  	netif_addr_lock_bh(dev);
  	__hw_addr_flush(&dev->mc);
  	netif_addr_unlock_bh(dev);
  }
  EXPORT_SYMBOL(dev_mc_flush);
  
  /**
   *	dev_mc_flush - Init multicast address list
   *	@dev: device
   *
   *	Init multicast address list.
   */
  void dev_mc_init(struct net_device *dev)
  {
  	__hw_addr_init(&dev->mc);
  }
  EXPORT_SYMBOL(dev_mc_init);