[net-next-2.6.git] / include / net / netns / generic.h

/*
 * generic net pointers
 */

#ifndef __NET_GENERIC_H__
#define __NET_GENERIC_H__

#include <linux/rcupdate.h>

/*
 * Generic net pointers are to be used by modules to put some private
 * stuff on the struct net without explicit struct net modification
 *
 * The rules are simple:
 * 1. register the ops with register_pernet_gen_device to get the id
 *    of your private pointer;
 * 2. call net_assign_generic() to put the private data on the struct
 *    net (most preferably this should be done in the ->init callback
 *    of the ops registered);
 * 3. do not change this pointer while the net is alive;
 * 4. do not try to have any private reference on the net_generic object.
 *
 * After accomplishing all of the above, the private pointer can be
 * accessed with the net_generic() call.
 */

struct net_generic {
	unsigned int len;
	struct rcu_head rcu;

	void *ptr[0];
};

static inline void *net_generic(struct net *net, int id)
{
	struct net_generic *ng;
	void *ptr;

	rcu_read_lock();
	ng = rcu_dereference(net->gen);
	BUG_ON(id == 0 || id > ng->len);
	ptr = ng->ptr[id - 1];
	rcu_read_unlock();

	return ptr;
}

extern int net_assign_generic(struct net *net, int id, void *data);
#endif
Commit	Line	Data
dec827d1 PE	1	/*
	2	* generic net pointers
	3	*/
	4
	5	#ifndef __NET_GENERIC_H__
	6	#define __NET_GENERIC_H__
	7
	8	#include <linux/rcupdate.h>
	9
	10	/*
	11	* Generic net pointers are to be used by modules to put some private
	12	* stuff on the struct net without explicit struct net modification
	13	*
	14	* The rules are simple:
	15	* 1. register the ops with register_pernet_gen_device to get the id
	16	* of your private pointer;
	17	* 2. call net_assign_generic() to put the private data on the struct
	18	* net (most preferably this should be done in the ->init callback
	19	* of the ops registered);
	20	* 3. do not change this pointer while the net is alive;
	21	* 4. do not try to have any private reference on the net_generic object.
	22	*
	23	* After accomplishing all of the above, the private pointer can be
	24	* accessed with the net_generic() call.
	25	*/
	26
	27	struct net_generic {
	28	unsigned int len;
	29	struct rcu_head rcu;
	30
	31	void *ptr[0];
	32	};
	33
	34	static inline void net_generic(struct net net, int id)
	35	{
	36	struct net_generic *ng;
	37	void *ptr;
	38
	39	rcu_read_lock();
	40	ng = rcu_dereference(net->gen);
	41	BUG_ON(id == 0 \|\| id > ng->len);
	42	ptr = ng->ptr[id - 1];
	43	rcu_read_unlock();
	44
	45	return ptr;
	46	}
	47
	48	extern int net_assign_generic(struct net net, int id, void data);
	49	#endif