[linux.git] / include / net / inetpeer.h

/*
 *		INETPEER - A storage for permanent information about peers
 *
 *  Authors:	Andrey V. Savochkin <[email protected]>
 */

#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>

typedef struct {
	union {
		__be32		a4;
		__be32		a6[4];
	};
	__u16	family;
} inet_peer_address_t;

struct inet_peer {
	/* group together avl_left,avl_right,v4daddr to speedup lookups */
	struct inet_peer __rcu	*avl_left, *avl_right;
	inet_peer_address_t	daddr;
	__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 <[email protected]>
	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
582a72da DM	16	typedef struct {
	17	union {
	18	__be32 a4;
	19	__be32 a6[4];
	20	};
	21	__u16 family;
	22	} inet_peer_address_t;
	23
fd2c3ef7	24	struct inet_peer {
78d79423	25	/* group together avl_left,avl_right,v4daddr to speedup lookups */
b914c4ea	26	struct inet_peer __rcu avl_left, avl_right;
582a72da	27	inet_peer_address_t daddr;
2c1409a0	28	__u32 avl_height;
d71209de	29	struct list_head unused;
4663afe2	30	__u32 dtime; /* the time of last use of not
1da177e4 LT	31	* referenced entries */
1da177e4 LT	32	atomic_t refcnt;
317fe0e6 ED	33	/*
	34	* Once inet_peer is queued for deletion (refcnt == -1), following fields
	35	* are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
	36	* We can share memory with rcu_head to keep inet_peer small
	37	* (less then 64 bytes)
	38	*/
	39	union {
	40	struct {
	41	atomic_t rid; /* Frag reception counter */
	42	atomic_t ip_id_count; /* IP ID for the next packet */
	43	__u32 tcp_ts;
	44	__u32 tcp_ts_stamp;
	45	};
	46	struct rcu_head rcu;
	47	};
1da177e4 LT	48	};
	49
	50	void inet_initpeers(void) __init;
	51
	52	/* can be called with or without local BH being disabled */
53576d9b	53	struct inet_peer *inet_getpeer(__be32 daddr, int create);
1da177e4	54
1da177e4	55	/* can be called from BH context or outside */
4663afe2	56	extern void inet_putpeer(struct inet_peer *p);
1da177e4	57
317fe0e6 ED	58	/*
	59	* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
	60	* tcp_ts_stamp if no refcount is taken on inet_peer
	61	*/
	62	static inline void inet_peer_refcheck(const struct inet_peer *p)
	63	{
	64	WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
	65	}
	66
	67
1da177e4 LT	68	/* can be called with or without local BH being disabled */
	69	static inline __u16 inet_getid(struct inet_peer *p, int more)
	70	{
2c1409a0	71	more++;
317fe0e6	72	inet_peer_refcheck(p);
2c1409a0	73	return atomic_add_return(more, &p->ip_id_count) - more;
1da177e4 LT	74	}
	75
	76	#endif /* _NET_INETPEER_H */