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 */
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