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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * INETPEER - A storage for permanent information about peers
3 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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
Eric Dumazetfd2c3ef2009-11-03 03:26:03 +000016struct inet_peer {
Eric Dumazet78d79422006-10-20 00:28:35 -070017 /* group together avl_left,avl_right,v4daddr to speedup lookups */
Eric Dumazetb914c4e2010-10-25 23:55:38 +000018 struct inet_peer __rcu *avl_left, *avl_right;
Eric Dumazet78d79422006-10-20 00:28:35 -070019 __be32 v4daddr; /* peer's address */
Eric Dumazet2c1409a2009-11-12 09:33:09 +000020 __u32 avl_height;
Pavel Emelyanovd71209d2007-11-12 21:27:28 -080021 struct list_head unused;
Eric Dumazet4663afe2006-10-12 21:21:06 -070022 __u32 dtime; /* the time of last use of not
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 * referenced entries */
24 atomic_t refcnt;
Eric Dumazet317fe0e2010-06-16 04:52:13 +000025 /*
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 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070040};
41
42void inet_initpeers(void) __init;
43
44/* can be called with or without local BH being disabled */
Al Viro53576d92006-09-26 22:18:43 -070045struct inet_peer *inet_getpeer(__be32 daddr, int create);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047/* can be called from BH context or outside */
Eric Dumazet4663afe2006-10-12 21:21:06 -070048extern void inet_putpeer(struct inet_peer *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Eric Dumazet317fe0e2010-06-16 04:52:13 +000050/*
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 */
54static inline void inet_peer_refcheck(const struct inet_peer *p)
55{
56 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
57}
58
59
Linus Torvalds1da177e2005-04-16 15:20:36 -070060/* can be called with or without local BH being disabled */
61static inline __u16 inet_getid(struct inet_peer *p, int more)
62{
Eric Dumazet2c1409a2009-11-12 09:33:09 +000063 more++;
Eric Dumazet317fe0e2010-06-16 04:52:13 +000064 inet_peer_refcheck(p);
Eric Dumazet2c1409a2009-11-12 09:33:09 +000065 return atomic_add_return(more, &p->ip_id_count) - more;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066}
67
68#endif /* _NET_INETPEER_H */