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		struct in6_addr		in6;
23	};
24};
25
26struct inetpeer_addr {
27	struct inetpeer_addr_base	addr;
28	__u16				family;
29};
30
31struct inet_peer {
32	/* group together avl_left,avl_right,v4daddr to speedup lookups */
33	struct inet_peer __rcu	*avl_left, *avl_right;
34	struct inetpeer_addr	daddr;
35	__u32			avl_height;
36
37	u32			metrics[RTAX_MAX];
38	u32			rate_tokens;	/* rate limiting for ICMP */
39	unsigned long		rate_last;
40	union {
41		struct list_head	gc_list;
42		struct rcu_head     gc_rcu;
43	};
44	/*
45	 * Once inet_peer is queued for deletion (refcnt == -1), following field
46	 * is not available: rid
47	 * We can share memory with rcu_head to help keep inet_peer small.
48	 */
49	union {
50		struct {
51			atomic_t			rid;		/* Frag reception counter */
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	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	daddr.addr.in6 = *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 */
175