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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 union {
40 struct list_head gc_list;
41 struct rcu_head gc_rcu;
42 };
43 /*
44 * Once inet_peer is queued for deletion (refcnt == -1), following field
45 * is not available: rid
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 };
52 struct rcu_head rcu;
53 struct inet_peer *gc_next;
54 };
55
56 /* following fields might be frequently dirtied */
57 __u32 dtime; /* the time of last use of not referenced entries */
58 atomic_t refcnt;
59};
60
61struct inet_peer_base {
62 struct inet_peer __rcu *root;
63 seqlock_t lock;
64 int total;
65};
66
67#define INETPEER_BASE_BIT 0x1UL
68
69static inline struct inet_peer *inetpeer_ptr(unsigned long val)
70{
71 BUG_ON(val & INETPEER_BASE_BIT);
72 return (struct inet_peer *) val;
73}
74
75static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
76{
77 if (!(val & INETPEER_BASE_BIT))
78 return NULL;
79 val &= ~INETPEER_BASE_BIT;
80 return (struct inet_peer_base *) val;
81}
82
83static inline bool inetpeer_ptr_is_peer(unsigned long val)
84{
85 return !(val & INETPEER_BASE_BIT);
86}
87
88static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
89{
90 /* This implicitly clears INETPEER_BASE_BIT */
91 *val = (unsigned long) peer;
92}
93
94static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
95{
96 unsigned long val = (unsigned long) peer;
97 unsigned long orig = *ptr;
98
99 if (!(orig & INETPEER_BASE_BIT) ||
100 cmpxchg(ptr, orig, val) != orig)
101 return false;
102 return true;
103}
104
105static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
106{
107 *ptr = (unsigned long) base | INETPEER_BASE_BIT;
108}
109
110static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
111{
112 unsigned long val = *from;
113
114 *to = val;
115 if (inetpeer_ptr_is_peer(val)) {
116 struct inet_peer *peer = inetpeer_ptr(val);
117 atomic_inc(&peer->refcnt);
118 }
119}
120
121void inet_peer_base_init(struct inet_peer_base *);
122
123void inet_initpeers(void) __init;
124
125#define INETPEER_METRICS_NEW (~(u32) 0)
126
127static inline bool inet_metrics_new(const struct inet_peer *p)
128{
129 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
130}
131
132/* can be called with or without local BH being disabled */
133struct inet_peer *inet_getpeer(struct inet_peer_base *base,
134 const struct inetpeer_addr *daddr,
135 int create);
136
137static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
138 __be32 v4daddr,
139 int create)
140{
141 struct inetpeer_addr daddr;
142
143 daddr.addr.a4 = v4daddr;
144 daddr.family = AF_INET;
145 return inet_getpeer(base, &daddr, create);
146}
147
148static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
149 const struct in6_addr *v6daddr,
150 int create)
151{
152 struct inetpeer_addr daddr;
153
154 *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
155 daddr.family = AF_INET6;
156 return inet_getpeer(base, &daddr, create);
157}
158
159/* can be called from BH context or outside */
160void inet_putpeer(struct inet_peer *p);
161bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
162
163void inetpeer_invalidate_tree(struct inet_peer_base *);
164
165/*
166 * temporary check to make sure we dont access rid, tcp_ts,
167 * tcp_ts_stamp if no refcount is taken on inet_peer
168 */
169static inline void inet_peer_refcheck(const struct inet_peer *p)
170{
171 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
172}
173#endif /* _NET_INETPEER_H */