text: /*
   * 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/list.h>
  #include <linux/proc_fs.h>
  
  /*
   * General list handling functions
   */
  
  static int __hw_addr_add_ex(struct netdev_hw_addr_list *list,
  			    unsigned char *addr, int addr_len,
  			    unsigned char addr_type, bool global)
  {
  	struct netdev_hw_addr *ha;
  	int alloc_size;
  
  	if (addr_len > MAX_ADDR_LEN)
  		return -EINVAL;
  
  	list_for_each_entry(ha, &list->list, list) {
  		if (!memcmp(ha->addr, addr, addr_len) &&
  		    ha->type == addr_type) {
  			if (global) {
  				/* check if addr is already used as global */
  				if (ha->global_use)
  					return 0;
  				else
  					ha->global_use = true;
  			}
  			ha->refcount++;
  			return 0;
  		}
  	}
  
  
  	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 = false;
  	list_add_tail_rcu(&ha->list, &list->list);
  	list->count++;
  	return 0;
  }
  
  static int __hw_addr_add(struct netdev_hw_addr_list *list, unsigned char *addr,
  			 int addr_len, unsigned char addr_type)
  {
  	return __hw_addr_add_ex(list, addr, addr_len, addr_type, false);
  }
  
  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_ex(struct netdev_hw_addr_list *list,
  			    unsigned char *addr, int addr_len,
  			    unsigned char addr_type, bool global)
  {
  	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)) {
  			if (global) {
  				if (!ha->global_use)
  					break;
  				else
  					ha->global_use = false;
  			}
  			if (--ha->refcount)
  				return 0;
  			list_del_rcu(&ha->list);
  			call_rcu(&ha->rcu_head, ha_rcu_free);
  			list->count--;
  			return 0;
  		}
  	}
  	return -ENOENT;
  }
  
  static int __hw_addr_del(struct netdev_hw_addr_list *list, unsigned char *addr,
  			 int addr_len, unsigned char addr_type)
  {
  	return __hw_addr_del_ex(list, addr, addr_len, addr_type, false);
  }
  
  int __hw_addr_add_multiple(struct netdev_hw_addr_list *to_list,
  			   struct netdev_hw_addr_list *from_list,
  			   int addr_len, unsigned char addr_type)
  {
  	int err;
  	struct netdev_hw_addr *ha, *ha2;
  	unsigned char type;
  
  	list_for_each_entry(ha, &from_list->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, list) {
  		if (ha2 == ha)
  			break;
  		type = addr_type ? addr_type : ha2->type;
  		__hw_addr_del(to_list, ha2->addr, addr_len, type);
  	}
  	return err;
  }
  EXPORT_SYMBOL(__hw_addr_add_multiple);
  
  void __hw_addr_del_multiple(struct netdev_hw_addr_list *to_list,
  			    struct netdev_hw_addr_list *from_list,
  			    int addr_len, unsigned char addr_type)
  {
  	struct netdev_hw_addr *ha;
  	unsigned char type __maybe_unused;
  
  	list_for_each_entry(ha, &from_list->list, list) {
  		type = addr_type ? addr_type : ha->type;
  		__hw_addr_del(to_list, ha->addr, addr_len, addr_type);
  	}
  }
  EXPORT_SYMBOL(__hw_addr_del_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->synced) {
  			err = __hw_addr_add(to_list, ha->addr,
  					    addr_len, ha->type);
  			if (err)
  				break;
  			ha->synced = true;
  			ha->refcount++;
  		} else if (ha->refcount == 1) {
  			__hw_addr_del(to_list, ha->addr, addr_len, ha->type);
  			__hw_addr_del(from_list, ha->addr, addr_len, ha->type);
  		}
  	}
  	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->synced) {
  			__hw_addr_del(to_list, ha->addr,
  				      addr_len, ha->type);
  			ha->synced = false;
  			__hw_addr_del(from_list, ha->addr,
  				      addr_len, ha->type);
  		}
  	}
  }
  EXPORT_SYMBOL(__hw_addr_unsync);
  
  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);
  		call_rcu(&ha->rcu_head, ha_rcu_free);
  	}
  	list->count = 0;
  }
  EXPORT_SYMBOL(__hw_addr_flush);
  
  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, 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, 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 (ha->addr == dev->dev_addr && 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);
  
  /**
   *	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(&to_dev->dev_addrs, &from_dev->dev_addrs,
  				     to_dev->addr_len, addr_type);
  	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(&to_dev->dev_addrs, &from_dev->dev_addrs,
  			       to_dev->addr_len, addr_type);
  	call_netdevice_notifiers(NETDEV_CHANGEADDR, to_dev);
  	return 0;
  }
  EXPORT_SYMBOL(dev_addr_del_multiple);
  
  /*
   * Unicast list handling functions
   */
  
  /**
   *	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, 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, 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_tx_lock_bh.
   *
   *	This function is intended to be called from the dev->set_rx_mode
   *	function of layered software devices.
   */
  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_bh(to);
  	err = __hw_addr_sync(&to->uc, &from->uc, to->addr_len);
  	if (!err)
  		__dev_set_rx_mode(to);
  	netif_addr_unlock_bh(to);
  	return err;
  }
  EXPORT_SYMBOL(dev_uc_sync);
  
  /**
   *	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(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
   */
  
  static int __dev_mc_add(struct net_device *dev, 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);
  	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, 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, 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, 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);
  	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, 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, unsigned char *addr)
  {
  	return __dev_mc_del(dev, addr, true);
  }
  EXPORT_SYMBOL(dev_mc_del_global);
  
  /**
   *	dev_mc_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_tx_lock_bh.
   *
   *	This function is intended to be called from the dev->set_multicast_list
   *	or dev->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_bh(to);
  	err = __hw_addr_sync(&to->mc, &from->mc, to->addr_len);
  	if (!err)
  		__dev_set_rx_mode(to);
  	netif_addr_unlock_bh(to);
  	return err;
  }
  EXPORT_SYMBOL(dev_mc_sync);
  
  /**
   *	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(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);
  
  #ifdef CONFIG_PROC_FS
  #include <linux/seq_file.h>
  
  static int dev_mc_seq_show(struct seq_file *seq, void *v)
  {
  	struct netdev_hw_addr *ha;
  	struct net_device *dev = v;
  
  	if (v == SEQ_START_TOKEN)
  		return 0;
  
  	netif_addr_lock_bh(dev);
  	netdev_for_each_mc_addr(ha, dev) {
  		int i;
  
  		seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
  			   dev->name, ha->refcount, ha->global_use);
  
  		for (i = 0; i < dev->addr_len; i++)
  			seq_printf(seq, "%02x", ha->addr[i]);
  
  		seq_putc(seq, '\n');
  	}
  	netif_addr_unlock_bh(dev);
  	return 0;
  }
  
  static const struct seq_operations dev_mc_seq_ops = {
  	.start = dev_seq_start,
  	.next  = dev_seq_next,
  	.stop  = dev_seq_stop,
  	.show  = dev_mc_seq_show,
  };
  
  static int dev_mc_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &dev_mc_seq_ops,
  			    sizeof(struct seq_net_private));
  }
  
  static const struct file_operations dev_mc_seq_fops = {
  	.owner	 = THIS_MODULE,
  	.open    = dev_mc_seq_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release_net,
  };
  
  #endif
  
  static int __net_init dev_mc_net_init(struct net *net)
  {
  	if (!proc_net_fops_create(net, "dev_mcast", 0, &dev_mc_seq_fops))
  		return -ENOMEM;
  	return 0;
  }
  
  static void __net_exit dev_mc_net_exit(struct net *net)
  {
  	proc_net_remove(net, "dev_mcast");
  }
  
  static struct pernet_operations __net_initdata dev_mc_net_ops = {
  	.init = dev_mc_net_init,
  	.exit = dev_mc_net_exit,
  };
  
  void __init dev_mcast_init(void)
  {
  	register_pernet_subsys(&dev_mc_net_ops);
  }
  
  