path: root/net/core/dev_addr_lists.c

/*
 * 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>

/*
 * General list handling functions
 */

static int __hw_addr_add(struct netdev_hw_addr_list *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;

	list_for_each_entry(ha, &list->list, list) {
		if (!memcmp(ha->addr, addr, addr_len) &&
		    ha->type == addr_type) {
			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->synced = false;
	list_add_tail_rcu(&ha->list, &list->list);
	list->count++;
	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(struct netdev_hw_addr_list *list, unsigned char *addr,
			 int addr_len, unsigned char addr_type)
{
	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 (--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_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;
}

static 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;

	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);
	}
}

static 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;
}

static 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);
		}
	}
}

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);
		call_rcu(&ha->rcu_head, ha_rcu_free);
	}
	list->count = 0;
}

static void __hw_addr_init(struct netdev_hw_addr_list *list)
{
	INIT_LIST_HEAD(&list->list);
	list->count = 0;
}

/*
 * 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
 */

/* To be filled here */