xref: /openbmc/linux/include/net/inetpeer.h (revision 930beb5a)
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 
18 struct inetpeer_addr_base {
19 	union {
20 		__be32			a4;
21 		__be32			a6[4];
22 	};
23 };
24 
25 struct inetpeer_addr {
26 	struct inetpeer_addr_base	addr;
27 	__u16				family;
28 };
29 
30 struct 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 
62 struct 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 
71 static 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 
77 static 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 
85 static inline bool inetpeer_ptr_is_peer(unsigned long val)
86 {
87 	return !(val & INETPEER_BASE_BIT);
88 }
89 
90 static 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 
96 static 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 
107 static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
108 {
109 	*ptr = (unsigned long) base | INETPEER_BASE_BIT;
110 }
111 
112 static 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 
123 void inet_peer_base_init(struct inet_peer_base *);
124 
125 void inet_initpeers(void) __init;
126 
127 #define INETPEER_METRICS_NEW	(~(u32) 0)
128 
129 static 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 */
135 struct inet_peer *inet_getpeer(struct inet_peer_base *base,
136 			       const struct inetpeer_addr *daddr,
137 			       int create);
138 
139 static 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 
150 static 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 */
162 void inet_putpeer(struct inet_peer *p);
163 bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout);
164 
165 void inetpeer_invalidate_tree(struct inet_peer_base *);
166 void 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  */
172 static 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 */
179 static 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 */
194