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Commit a0a400d7 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NET]: dev_mcast: add multicast list synchronization helpers 



The method drivers currently use to synchronize multicast lists is not
very pretty:

- walk the multicast list
- search each entry on a copy of the previous list
- if new add to lower device
- walk the copy of the previous list
- search each entry on the current list
- if removed delete from lower device
- copy entire list

This patch adds a new field to struct dev_addr_list to store the
synchronization state and adds two helper functions for synchronization
and cleanup.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 24023451

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -190,6 +190,7 @@ struct dev_addr_list 
	struct dev_addr_list	*next;

	u8			da_addr[MAX_ADDR_LEN];

	u8			da_addrlen;

	u8			da_synced;

	int			da_users;

	int			da_gusers;

};
@@ -1103,6 +1104,8 @@ extern int dev_unicast_delete(struct net_device *dev, void *addr, int alen); 
extern int		dev_unicast_add(struct net_device *dev, void *addr, int alen);

extern int 		dev_mc_delete(struct net_device *dev, void *addr, int alen, int all);

extern int		dev_mc_add(struct net_device *dev, void *addr, int alen, int newonly);

extern int		dev_mc_sync(struct net_device *to, struct net_device *from);

extern void		dev_mc_unsync(struct net_device *to, struct net_device *from);

extern void		dev_mc_discard(struct net_device *dev);

extern int 		__dev_addr_delete(struct dev_addr_list **list, int *count, void *addr, int alen, int all);

extern int		__dev_addr_add(struct dev_addr_list **list, int *count, void *addr, int alen, int newonly);

net/core/dev_mcast.c

+75 −0
Original line number Diff line number Diff line
@@ -102,6 +102,81 @@ int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl) 
	return err;

}



/**

 *	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_tx_lock_bh.

 *

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

 *	function of layered software devices.

 */

int dev_mc_sync(struct net_device *to, struct net_device *from)

{

	struct dev_addr_list *da;

	int err = 0;



	netif_tx_lock_bh(to);

	for (da = from->mc_list; da != NULL; da = da->next) {

		if (!da->da_synced) {

			err = __dev_addr_add(&to->mc_list, &to->mc_count,

					     da->da_addr, da->da_addrlen, 0);

			if (err < 0)

				break;

			da->da_synced = 1;

			da->da_users++;

		} else if (da->da_users == 1) {

			__dev_addr_delete(&to->mc_list, &to->mc_count,

					  da->da_addr, da->da_addrlen, 0);

			__dev_addr_delete(&from->mc_list, &from->mc_count,

					  da->da_addr, da->da_addrlen, 0);

		}

	}

	if (!err)

		__dev_set_rx_mode(to);

	netif_tx_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)

{

	struct dev_addr_list *da;



	netif_tx_lock_bh(from);

	netif_tx_lock_bh(to);



	for (da = from->mc_list; da != NULL; da = da->next) {

		if (!da->da_synced)

			continue;

		__dev_addr_delete(&to->mc_list, &to->mc_count,

				  da->da_addr, da->da_addrlen, 0);

		da->da_synced = 0;

		__dev_addr_delete(&from->mc_list, &from->mc_count,

				  da->da_addr, da->da_addrlen, 0);

	}

	__dev_set_rx_mode(to);



	netif_tx_unlock_bh(to);

	netif_tx_unlock_bh(from);

}

EXPORT_SYMBOL(dev_mc_unsync);



/*

 *	Discard multicast list when a device is downed

 */