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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 u32 flush_seq;
65 int total;
66};
67
68#define INETPEER_BASE_BIT 0x1UL
69
70static inline struct inet_peer *inetpeer_ptr(unsigned long val)
71{
72 BUG_ON(val & INETPEER_BASE_BIT);
73 return (struct inet_peer *) val;
74}
75
76static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
77{
78 if (!(val & INETPEER_BASE_BIT))
79 return NULL;
80 val &= ~INETPEER_BASE_BIT;
81 return (struct inet_peer_base *) val;
82}
83
84static inline bool inetpeer_ptr_is_peer(unsigned long val)
85{
86 return !(val & INETPEER_BASE_BIT);
87}
88
89static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
90{
91 /* This implicitly clears INETPEER_BASE_BIT */
92 *val = (unsigned long) peer;
93}
94
95static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
96{
97 unsigned long val = (unsigned long) peer;
98 unsigned long orig = *ptr;
99
100 if (!(orig & INETPEER_BASE_BIT) ||
101 cmpxchg(ptr, orig, val) != orig)
102 return false;
103 return true;
104}
105
106static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
107{
108 *ptr = (unsigned long) base | INETPEER_BASE_BIT;
109}
110
111static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
112{
113 unsigned long val = *from;
114
115 *to = val;
116 if (inetpeer_ptr_is_peer(val)) {
117 struct inet_peer *peer = inetpeer_ptr(val);
118 atomic_inc(&peer->refcnt);
119 }
120}
121
122void inet_peer_base_init(struct inet_peer_base *);
123
124void inet_initpeers(void) __init;
125
126#define INETPEER_METRICS_NEW (~(u32) 0)
127
128static inline bool inet_metrics_new(const struct inet_peer *p)
129{
130 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
131}
132
133/* can be called with or without local BH being disabled */
134struct inet_peer *inet_getpeer(struct inet_peer_base *base,
135 const struct inetpeer_addr *daddr,
136 int create);
137
138static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
139 __be32 v4daddr,
140 int create)
141{
142 struct inetpeer_addr daddr;
143
144 daddr.addr.a4 = v4daddr;
145 daddr.family = AF_INET;
146 return inet_getpeer(base, &daddr, create);
147}
148
149static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
150 const struct in6_addr *v6daddr,
151 int create)
152{
153 struct inetpeer_addr daddr;
154
155 *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
156 daddr.family = AF_INET6;
157 return inet_getpeer(base, &daddr, create);
158}
159
160/* can be called from BH context or outside */
161void inet_putpeer(struct inet_peer *p);
162bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
163
164void inetpeer_invalidate_tree(struct inet_peer_base *);
165
166/*
167 * temporary check to make sure we dont access rid, tcp_ts,
168 * tcp_ts_stamp if no refcount is taken on inet_peer
169 */
170static inline void inet_peer_refcheck(const struct inet_peer *p)
171{
172 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
173}
174#endif /* _NET_INETPEER_H */