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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 fields
45 * are not available: rid, ip_id_count
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 };
53 struct rcu_head rcu;
54 struct inet_peer *gc_next;
55 };
56
57 /* following fields might be frequently dirtied */
58 __u32 dtime; /* the time of last use of not referenced entries */
59 atomic_t refcnt;
60};
61
62struct inet_peer_base {
63 struct inet_peer __rcu *root;
64 seqlock_t lock;
65 u32 flush_seq;
66 int total;
67};
68
69#define INETPEER_BASE_BIT 0x1UL
70
71static inline struct inet_peer *inetpeer_ptr(unsigned long val)
72{
73 BUG_ON(val & INETPEER_BASE_BIT);
74 return (struct inet_peer *) val;
75}
76
77static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
78{
79 if (!(val & INETPEER_BASE_BIT))
80 return NULL;
81 val &= ~INETPEER_BASE_BIT;
82 return (struct inet_peer_base *) val;
83}
84
85static inline bool inetpeer_ptr_is_peer(unsigned long val)
86{
87 return !(val & INETPEER_BASE_BIT);
88}
89
90static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
91{
92 /* This implicitly clears INETPEER_BASE_BIT */
93 *val = (unsigned long) peer;
94}
95
96static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
97{
98 unsigned long val = (unsigned long) peer;
99 unsigned long orig = *ptr;
100
101 if (!(orig & INETPEER_BASE_BIT) ||
102 cmpxchg(ptr, orig, val) != orig)
103 return false;
104 return true;
105}
106
107static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
108{
109 *ptr = (unsigned long) base | INETPEER_BASE_BIT;
110}
111
112static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
113{
114 unsigned long val = *from;
115
116 *to = val;
117 if (inetpeer_ptr_is_peer(val)) {
118 struct inet_peer *peer = inetpeer_ptr(val);
119 atomic_inc(&peer->refcnt);
120 }
121}
122
123void inet_peer_base_init(struct inet_peer_base *);
124
125void inet_initpeers(void) __init;
126
127#define INETPEER_METRICS_NEW (~(u32) 0)
128
129static inline bool inet_metrics_new(const struct inet_peer *p)
130{
131 return p->metrics[RTAX_LOCK-1] == INETPEER_METRICS_NEW;
132}
133
134/* can be called with or without local BH being disabled */
135struct inet_peer *inet_getpeer(struct inet_peer_base *base,
136 const struct inetpeer_addr *daddr,
137 int create);
138
139static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base,
140 __be32 v4daddr,
141 int create)
142{
143 struct inetpeer_addr daddr;
144
145 daddr.addr.a4 = v4daddr;
146 daddr.family = AF_INET;
147 return inet_getpeer(base, &daddr, create);
148}
149
150static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base,
151 const struct in6_addr *v6daddr,
152 int create)
153{
154 struct inetpeer_addr daddr;
155
156 *(struct in6_addr *)daddr.addr.a6 = *v6daddr;
157 daddr.family = AF_INET6;
158 return inet_getpeer(base, &daddr, create);
159}
160
161/* can be called from BH context or outside */
162void inet_putpeer(struct inet_peer *p);
163bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
164
165void inetpeer_invalidate_tree(struct inet_peer_base *);
166void inetpeer_invalidate_family(int family);
167
168/*
169 * temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
170 * tcp_ts_stamp if no refcount is taken on inet_peer
171 */
172static inline void inet_peer_refcheck(const struct inet_peer *p)
173{
174 WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
175}
176
177
178/* can be called with or without local BH being disabled */
179static inline int inet_getid(struct inet_peer *p, int more)
180{
181 int old, new;
182 more++;
183 inet_peer_refcheck(p);
184 do {
185 old = atomic_read(&p->ip_id_count);
186 new = old + more;
187 if (!new)
188 new = 1;
189 } while (atomic_cmpxchg(&p->ip_id_count, old, new) != old);
190 return new;
191}
192
193#endif /* _NET_INETPEER_H */