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911362c7 PA |
1 | /* |
2 | * net/core/dst_cache.c - dst entry cache | |
3 | * | |
4 | * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/percpu.h> | |
14 | #include <net/dst_cache.h> | |
15 | #include <net/route.h> | |
16 | #if IS_ENABLED(CONFIG_IPV6) | |
17 | #include <net/ip6_fib.h> | |
18 | #endif | |
19 | #include <uapi/linux/in.h> | |
20 | ||
21 | struct dst_cache_pcpu { | |
22 | unsigned long refresh_ts; | |
23 | struct dst_entry *dst; | |
24 | u32 cookie; | |
25 | union { | |
26 | struct in_addr in_saddr; | |
27 | struct in6_addr in6_saddr; | |
28 | }; | |
29 | }; | |
30 | ||
b73f96fc WF |
31 | static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache, |
32 | struct dst_entry *dst, u32 cookie) | |
911362c7 PA |
33 | { |
34 | dst_release(dst_cache->dst); | |
35 | if (dst) | |
36 | dst_hold(dst); | |
37 | ||
38 | dst_cache->cookie = cookie; | |
39 | dst_cache->dst = dst; | |
40 | } | |
41 | ||
b73f96fc WF |
42 | static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache, |
43 | struct dst_cache_pcpu *idst) | |
911362c7 PA |
44 | { |
45 | struct dst_entry *dst; | |
46 | ||
47 | dst = idst->dst; | |
48 | if (!dst) | |
49 | goto fail; | |
50 | ||
51 | /* the cache already hold a dst reference; it can't go away */ | |
52 | dst_hold(dst); | |
53 | ||
54 | if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) || | |
55 | (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) { | |
56 | dst_cache_per_cpu_dst_set(idst, NULL, 0); | |
57 | dst_release(dst); | |
58 | goto fail; | |
59 | } | |
60 | return dst; | |
61 | ||
62 | fail: | |
63 | idst->refresh_ts = jiffies; | |
64 | return NULL; | |
65 | } | |
66 | ||
67 | struct dst_entry *dst_cache_get(struct dst_cache *dst_cache) | |
68 | { | |
69 | if (!dst_cache->cache) | |
70 | return NULL; | |
71 | ||
72 | return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache)); | |
73 | } | |
74 | EXPORT_SYMBOL_GPL(dst_cache_get); | |
75 | ||
76 | struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr) | |
77 | { | |
78 | struct dst_cache_pcpu *idst; | |
79 | struct dst_entry *dst; | |
80 | ||
81 | if (!dst_cache->cache) | |
82 | return NULL; | |
83 | ||
84 | idst = this_cpu_ptr(dst_cache->cache); | |
85 | dst = dst_cache_per_cpu_get(dst_cache, idst); | |
86 | if (!dst) | |
87 | return NULL; | |
88 | ||
89 | *saddr = idst->in_saddr.s_addr; | |
90 | return container_of(dst, struct rtable, dst); | |
91 | } | |
92 | EXPORT_SYMBOL_GPL(dst_cache_get_ip4); | |
93 | ||
94 | void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst, | |
95 | __be32 saddr) | |
96 | { | |
97 | struct dst_cache_pcpu *idst; | |
98 | ||
99 | if (!dst_cache->cache) | |
100 | return; | |
101 | ||
102 | idst = this_cpu_ptr(dst_cache->cache); | |
103 | dst_cache_per_cpu_dst_set(idst, dst, 0); | |
104 | idst->in_saddr.s_addr = saddr; | |
105 | } | |
106 | EXPORT_SYMBOL_GPL(dst_cache_set_ip4); | |
107 | ||
108 | #if IS_ENABLED(CONFIG_IPV6) | |
109 | void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst, | |
4c1342d9 | 110 | const struct in6_addr *saddr) |
911362c7 PA |
111 | { |
112 | struct dst_cache_pcpu *idst; | |
113 | ||
114 | if (!dst_cache->cache) | |
115 | return; | |
116 | ||
117 | idst = this_cpu_ptr(dst_cache->cache); | |
118 | dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst, | |
119 | rt6_get_cookie((struct rt6_info *)dst)); | |
4c1342d9 | 120 | idst->in6_saddr = *saddr; |
911362c7 PA |
121 | } |
122 | EXPORT_SYMBOL_GPL(dst_cache_set_ip6); | |
123 | ||
124 | struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache, | |
125 | struct in6_addr *saddr) | |
126 | { | |
127 | struct dst_cache_pcpu *idst; | |
128 | struct dst_entry *dst; | |
129 | ||
130 | if (!dst_cache->cache) | |
131 | return NULL; | |
132 | ||
133 | idst = this_cpu_ptr(dst_cache->cache); | |
134 | dst = dst_cache_per_cpu_get(dst_cache, idst); | |
135 | if (!dst) | |
136 | return NULL; | |
137 | ||
138 | *saddr = idst->in6_saddr; | |
139 | return dst; | |
140 | } | |
141 | EXPORT_SYMBOL_GPL(dst_cache_get_ip6); | |
142 | #endif | |
143 | ||
144 | int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp) | |
145 | { | |
146 | dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu, | |
147 | gfp | __GFP_ZERO); | |
148 | if (!dst_cache->cache) | |
149 | return -ENOMEM; | |
150 | ||
151 | dst_cache_reset(dst_cache); | |
152 | return 0; | |
153 | } | |
154 | EXPORT_SYMBOL_GPL(dst_cache_init); | |
155 | ||
156 | void dst_cache_destroy(struct dst_cache *dst_cache) | |
157 | { | |
158 | int i; | |
159 | ||
160 | if (!dst_cache->cache) | |
161 | return; | |
162 | ||
163 | for_each_possible_cpu(i) | |
164 | dst_release(per_cpu_ptr(dst_cache->cache, i)->dst); | |
165 | ||
166 | free_percpu(dst_cache->cache); | |
167 | } | |
168 | EXPORT_SYMBOL_GPL(dst_cache_destroy); |