1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _NET_DST_CACHE_H
3 #define _NET_DST_CACHE_H
4 
5 #include <linux/jiffies.h>
6 #include <net/dst.h>
7 #if IS_ENABLED(CONFIG_IPV6)
8 #include <net/ip6_fib.h>
9 #endif
10 
11 struct dst_cache {
12 	struct dst_cache_pcpu __percpu *cache;
13 	unsigned long reset_ts;
14 };
15 
16 /**
17  *	dst_cache_get - perform cache lookup
18  *	@dst_cache: the cache
19  *
20  *	The caller should use dst_cache_get_ip4() if it need to retrieve the
21  *	source address to be used when xmitting to the cached dst.
22  *	local BH must be disabled.
23  */
24 struct dst_entry *dst_cache_get(struct dst_cache *dst_cache);
25 
26 /**
27  *	dst_cache_get_ip4 - perform cache lookup and fetch ipv4 source address
28  *	@dst_cache: the cache
29  *	@saddr: return value for the retrieved source address
30  *
31  *	local BH must be disabled.
32  */
33 struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr);
34 
35 /**
36  *	dst_cache_set_ip4 - store the ipv4 dst into the cache
37  *	@dst_cache: the cache
38  *	@dst: the entry to be cached
39  *	@saddr: the source address to be stored inside the cache
40  *
41  *	local BH must be disabled.
42  */
43 void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
44 		       __be32 saddr);
45 
46 #if IS_ENABLED(CONFIG_IPV6)
47 
48 /**
49  *	dst_cache_set_ip6 - store the ipv6 dst into the cache
50  *	@dst_cache: the cache
51  *	@dst: the entry to be cached
52  *	@saddr: the source address to be stored inside the cache
53  *
54  *	local BH must be disabled.
55  */
56 void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
57 		       const struct in6_addr *saddr);
58 
59 /**
60  *	dst_cache_get_ip6 - perform cache lookup and fetch ipv6 source address
61  *	@dst_cache: the cache
62  *	@saddr: return value for the retrieved source address
63  *
64  *	local BH must be disabled.
65  */
66 struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
67 				    struct in6_addr *saddr);
68 #endif
69 
70 /**
71  *	dst_cache_reset - invalidate the cache contents
72  *	@dst_cache: the cache
73  *
74  *	This does not free the cached dst to avoid races and contentions.
75  *	the dst will be freed on later cache lookup.
76  */
dst_cache_reset(struct dst_cache * dst_cache)77 static inline void dst_cache_reset(struct dst_cache *dst_cache)
78 {
79 	dst_cache->reset_ts = jiffies;
80 }
81 
82 /**
83  *	dst_cache_init - initialize the cache, allocating the required storage
84  *	@dst_cache: the cache
85  *	@gfp: allocation flags
86  */
87 int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp);
88 
89 /**
90  *	dst_cache_destroy - empty the cache and free the allocated storage
91  *	@dst_cache: the cache
92  *
93  *	No synchronization is enforced: it must be called only when the cache
94  *	is unsed.
95  */
96 void dst_cache_destroy(struct dst_cache *dst_cache);
97 
98 #endif
99