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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 <asm/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 struct list_head unused;
36 __u32 dtime; /* the time of last use of not
37 * referenced entries */
38 atomic_t refcnt;
39 /*
40 * Once inet_peer is queued for deletion (refcnt == -1), following fields
41 * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp, metrics
42 * We can share memory with rcu_head to help keep inet_peer small.
43 */
44 union {
45 struct {
46 atomic_t rid; /* Frag reception counter */
47 atomic_t ip_id_count; /* IP ID for the next packet */
48 __u32 tcp_ts;
49 __u32 tcp_ts_stamp;
50 u32 metrics[RTAX_MAX];
51 u32 rate_tokens; /* rate limiting for ICMP */
52 unsigned long rate_last;
53 unsigned long pmtu_expires;
54 u32 pmtu_orig;
55 u32 pmtu_learned;
56 struct inetpeer_addr_base redirect_learned;
57 };
58 struct rcu_head rcu;
59 };
60};
61
62void inet_initpeers(void) __init;
63
64#define INETPEER_METRICS_NEW (~(u32) 0)
65
66static inline bool inet_metrics_new(const struct inet_peer *p)
67{
68 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
69}
70
71/* can be called with or without local BH being disabled */
72struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create);
73
74static inline struct inet_peer *inet_getpeer_v4(__be32 v4daddr, int create)
75{
76 struct inetpeer_addr daddr;
77
78 daddr.addr.a4 = v4daddr;
79 daddr.family = AF_INET;
80 return inet_getpeer(&daddr, create);
81}
82
83static inline struct inet_peer *inet_getpeer_v6(const struct in6_addr *v6daddr, int create)
84{
85 struct inetpeer_addr daddr;
86
87 ipv6_addr_copy((struct in6_addr *)daddr.addr.a6, v6daddr);
88 daddr.family = AF_INET6;
89 return inet_getpeer(&daddr, create);
90}
91
92/* can be called from BH context or outside */
93extern void inet_putpeer(struct inet_peer *p);
94extern bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
95
96/*
97 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
98 * tcp_ts_stamp if no refcount is taken on inet_peer
99 */
100static inline void inet_peer_refcheck(const struct inet_peer *p)
101{
102 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
103}
104
105
106/* can be called with or without local BH being disabled */
107static inline __u16 inet_getid(struct inet_peer *p, int more)
108{
109 more++;
110 inet_peer_refcheck(p);
111 return atomic_add_return(more, &p->ip_id_count) - more;
112}
113
114#endif /* _NET_INETPEER_H */