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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 /*
44 * Once inet_peer is queued for deletion (refcnt == -1), following fields
45 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
46 * We can share memory with rcu_head to help keep inet_peer small.
47 */
48 union {
49 struct {
50 atomic_t rid; /* Frag reception counter */
51 atomic_t ip_id_count; /* IP ID for the next packet */
52 __u32 tcp_ts;
53 __u32 tcp_ts_stamp;
54 };
55 struct rcu_head rcu;
56 struct inet_peer *gc_next;
57 };
58
59 /* following fields might be frequently dirtied */
60 __u32 dtime; /* the time of last use of not referenced entries */
61 atomic_t refcnt;
62};
63
64void inet_initpeers(void) __init;
65
66#define INETPEER_METRICS_NEW (~(u32) 0)
67
68static inline bool inet_metrics_new(const struct inet_peer *p)
69{
70 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
71}
72
73/* can be called with or without local BH being disabled */
74struct inet_peer *inet_getpeer(const struct inetpeer_addr *daddr, int create);
75
76static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
77{
78 struct inetpeer_addr daddr;
79
80 daddr.addr.a4 = v4daddr;
81 daddr.family = AF_INET;
82 return inet_getpeer(&daddr, create);
83}
84
85static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create)
86{
87 struct inetpeer_addr daddr;
88
89 ipv6_addr_copy((struct in6_addr *)daddr.addr.a6, v6daddr);
90 daddr.family = AF_INET6;
91 return inet_getpeer(&daddr, create);
92}
93
94/* can be called from BH context or outside */
95extern void inet_putpeer(struct inet_peer *p);
96extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
97
98/*
99 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
100 * tcp_ts_stamp if no refcount is taken on inet_peer
101 */
102static inline void inet_peer_refcheck(const struct inet_peer *p)
103{
104 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
105}
106
107
108/* can be called with or without local BH being disabled */
109static inline int inet_getid(struct inet_peer *p, int more)
110{
111 int old, new;
112 more++;
113 inet_peer_refcheck(p);
114 do {
115 old = atomic_read(&p->ip_id_count);
116 new = old + more;
117 if (!new)
118 new = 1;
119 } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
120 return new;
121}
122
123#endif /* _NET_INETPEER_H */