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linux
1/*
2 * INETPEER - A storage for permanent information about peers
3 *
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 <linux/rtnetlink.h>
15#include <net/ipv6.h>
16#include <linux/atomic.h>
17
18struct inetpeer_addr_base {
19 union {
20 __be32 a4;
21 __be32 a6[4];
22 };
23};
24
25struct inetpeer_addr {
26 struct inetpeer_addr_base addr;
27 __u16 family;
28};
29
30struct inet_peer {
31 /* group together avl_left,avl_right,v4daddr to speedup lookups */
32 struct inet_peer __rcu *avl_left, *avl_right;
33 struct inetpeer_addr daddr;
34 __u32 avl_height;
35
36 u32 metrics[RTAX_MAX];
37 u32 rate_tokens; /* rate limiting for ICMP */
38 unsigned long rate_last;
39 unsigned long pmtu_expires;
40 u32 pmtu_orig;
41 u32 pmtu_learned;
42 struct inetpeer_addr_base redirect_learned;
43 union {
44 struct list_head gc_list;
45 struct rcu_head gc_rcu;
46 };
47 /*
48 * Once inet_peer is queued for deletion (refcnt == -1), following fields
49 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
50 * We can share memory with rcu_head to help keep inet_peer small.
51 */
52 union {
53 struct {
54 atomic_t rid; /* Frag reception counter */
55 atomic_t ip_id_count; /* IP ID for the next packet */
56 __u32 tcp_ts;
57 __u32 tcp_ts_stamp;
58 };
59 struct rcu_head rcu;
60 struct inet_peer *gc_next;
61 };
62
63 /* following fields might be frequently dirtied */
64 __u32 dtime; /* the time of last use of not referenced entries */
65 atomic_t refcnt;
66};
67
68void inet_initpeers(void) __init;
69
70#define INETPEER_METRICS_NEW (~(u32) 0)
71
72static inline bool inet_metrics_new(const struct inet_peer *p)
73{
74 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
75}
76
77/* can be called with or without local BH being disabled */
78struct inet_peer *inet_getpeer(const struct inetpeer_addr *daddr, int create);
79
80static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
81{
82 struct inetpeer_addr daddr;
83
84 daddr.addr.a4 = v4daddr;
85 daddr.family = AF_INET;
86 return inet_getpeer(&daddr, create);
87}
88
89static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create)
90{
91 struct inetpeer_addr daddr;
92
93 *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
94 daddr.family = AF_INET6;
95 return inet_getpeer(&daddr, create);
96}
97
98/* can be called from BH context or outside */
99extern void inet_putpeer(struct inet_peer *p);
100extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
101
102extern void inetpeer_invalidate_tree(int family);
103
104/*
105 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
106 * tcp_ts_stamp if no refcount is taken on inet_peer
107 */
108static inline void inet_peer_refcheck(const struct inet_peer *p)
109{
110 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
111}
112
113
114/* can be called with or without local BH being disabled */
115static inline int inet_getid(struct inet_peer *p, int more)
116{
117 int old, new;
118 more++;
119 inet_peer_refcheck(p);
120 do {
121 old = atomic_read(&p->ip_id_count);
122 new = old + more;
123 if (!new)
124 new = 1;
125 } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
126 return new;
127}
128
129#endif /* _NET_INETPEER_H */