[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. set pernet_operations->id.  After register_pernet_device you
 *    will have the id of your private pointer.
 * 2. Either set pernet_operations->size (to have the code allocate and
 *    free a private structure pointed to from struct net ) or 
 *    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:
65c0cfaf EB	15	* 1. set pernet_operations->id. After register_pernet_device you
	16	* will have the id of your private pointer.
	17	* 2. Either set pernet_operations->size (to have the code allocate and
	18	* free a private structure pointed to from struct net ) or
	19	* call net_assign_generic() to put the private data on the struct
dec827d1 PE	20	* net (most preferably this should be done in the ->init callback
	21	* of the ops registered);
	22	* 3. do not change this pointer while the net is alive;
	23	* 4. do not try to have any private reference on the net_generic object.
	24	*
	25	* After accomplishing all of the above, the private pointer can be
	26	* accessed with the net_generic() call.
	27	*/
	28
	29	struct net_generic {
	30	unsigned int len;
	31	struct rcu_head rcu;
	32
	33	void *ptr[0];
	34	};
	35
	36	static inline void net_generic(struct net net, int id)
	37	{
	38	struct net_generic *ng;
	39	void *ptr;
	40
	41	rcu_read_lock();
	42	ng = rcu_dereference(net->gen);
	43	BUG_ON(id == 0 \|\| id > ng->len);
	44	ptr = ng->ptr[id - 1];
	45	rcu_read_unlock();
	46
	47	return ptr;
	48	}
	49
	50	extern int net_assign_generic(struct net net, int id, void data);
	51	#endif