[net-next-2.6.git] / include / net / inetpeer.h

/*
 *		INETPEER - A storage for permanent information about peers
 *
 *  Authors:	Andrey V. Savochkin <saw@msu.ru>
 */

#ifndef _NET_INETPEER_H
#define _NET_INETPEER_H

#include <linux/types.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>

struct inet_peer {
	/* group together avl_left,avl_right,v4daddr to speedup lookups */
	struct inet_peer __rcu	*avl_left, *avl_right;
	__be32			v4daddr;	/* peer's address */
	__u32			avl_height;
	struct list_head	unused;
	__u32			dtime;		/* the time of last use of not
						 * referenced entries */
	atomic_t		refcnt;
	/*
	 * Once inet_peer is queued for deletion (refcnt == -1), following fields
	 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
	 * We can share memory with rcu_head to keep inet_peer small
	 * (less then 64 bytes)
	 */
	union {
		struct {
			atomic_t	rid;		/* Frag reception counter */
			atomic_t	ip_id_count;	/* IP ID for the next packet */
			__u32		tcp_ts;
			__u32		tcp_ts_stamp;
		};
		struct rcu_head         rcu;
	};
};

void			inet_initpeers(void) __init;

/* can be called with or without local BH being disabled */
struct inet_peer	*inet_getpeer(__be32 daddr, int create);

/* can be called from BH context or outside */
extern void inet_putpeer(struct inet_peer *p);

/*
 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
 * tcp_ts_stamp if no refcount is taken on inet_peer
 */
static inline void inet_peer_refcheck(const struct inet_peer *p)
{
	WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
}


/* can be called with or without local BH being disabled */
static inline __u16	inet_getid(struct inet_peer *p, int more)
{
	more++;
	inet_peer_refcheck(p);
	return atomic_add_return(more, &p->ip_id_count) - more;
}

#endif /* _NET_INETPEER_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* INETPEER - A storage for permanent information about peers
	3	*
1da177e4 LT	4	* Authors: Andrey V. Savochkin <saw@msu.ru>
	5	*/
	6
	7	#ifndef _NET_INETPEER_H
	8	#define _NET_INETPEER_H
	9
	10	#include <linux/types.h>
	11	#include <linux/init.h>
	12	#include <linux/jiffies.h>
	13	#include <linux/spinlock.h>
	14	#include <asm/atomic.h>
	15
fd2c3ef7	16	struct inet_peer {
78d79423	17	/* group together avl_left,avl_right,v4daddr to speedup lookups */
b914c4ea	18	struct inet_peer __rcu avl_left, avl_right;
78d79423	19	__be32 v4daddr; /* peer's address */
2c1409a0	20	__u32 avl_height;
d71209de	21	struct list_head unused;
4663afe2	22	__u32 dtime; /* the time of last use of not
1da177e4 LT	23	* referenced entries */
1da177e4 LT	24	atomic_t refcnt;
317fe0e6 ED	25	/*
	26	* Once inet_peer is queued for deletion (refcnt == -1), following fields
	27	* are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
	28	* We can share memory with rcu_head to keep inet_peer small
	29	* (less then 64 bytes)
	30	*/
	31	union {
	32	struct {
	33	atomic_t rid; /* Frag reception counter */
	34	atomic_t ip_id_count; /* IP ID for the next packet */
	35	__u32 tcp_ts;
	36	__u32 tcp_ts_stamp;
	37	};
	38	struct rcu_head rcu;
	39	};
1da177e4 LT	40	};
	41
	42	void inet_initpeers(void) __init;
	43
	44	/* can be called with or without local BH being disabled */
53576d9b	45	struct inet_peer *inet_getpeer(__be32 daddr, int create);
1da177e4	46
1da177e4	47	/* can be called from BH context or outside */
4663afe2	48	extern void inet_putpeer(struct inet_peer *p);
1da177e4	49
317fe0e6 ED	50	/*
	51	* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
	52	* tcp_ts_stamp if no refcount is taken on inet_peer
	53	*/
	54	static inline void inet_peer_refcheck(const struct inet_peer *p)
	55	{
	56	WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
	57	}
	58
	59
1da177e4 LT	60	/* can be called with or without local BH being disabled */
	61	static inline __u16 inet_getid(struct inet_peer *p, int more)
	62	{
2c1409a0	63	more++;
317fe0e6	64	inet_peer_refcheck(p);
2c1409a0	65	return atomic_add_return(more, &p->ip_id_count) - more;
1da177e4 LT	66	}
	67
	68	#endif /* _NET_INETPEER_H */