1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * net/core/dst_cache.c - dst entry cache |
4 | * |
5 | * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com> |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/percpu.h> |
10 | #include <net/dst_cache.h> |
11 | #include <net/route.h> |
12 | #if IS_ENABLED(CONFIG_IPV6) |
13 | #include <net/ip6_fib.h> |
14 | #endif |
15 | #include <uapi/linux/in.h> |
16 | |
17 | struct dst_cache_pcpu { |
18 | unsigned long refresh_ts; |
19 | struct dst_entry *dst; |
20 | u32 cookie; |
21 | union { |
22 | struct in_addr in_saddr; |
23 | struct in6_addr in6_saddr; |
24 | }; |
25 | }; |
26 | |
27 | static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache, |
28 | struct dst_entry *dst, u32 cookie) |
29 | { |
30 | dst_release(dst: dst_cache->dst); |
31 | if (dst) |
32 | dst_hold(dst); |
33 | |
34 | dst_cache->cookie = cookie; |
35 | dst_cache->dst = dst; |
36 | } |
37 | |
38 | static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache, |
39 | struct dst_cache_pcpu *idst) |
40 | { |
41 | struct dst_entry *dst; |
42 | |
43 | dst = idst->dst; |
44 | if (!dst) |
45 | goto fail; |
46 | |
47 | /* the cache already hold a dst reference; it can't go away */ |
48 | dst_hold(dst); |
49 | |
50 | if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) || |
51 | (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) { |
52 | dst_cache_per_cpu_dst_set(dst_cache: idst, NULL, cookie: 0); |
53 | dst_release(dst); |
54 | goto fail; |
55 | } |
56 | return dst; |
57 | |
58 | fail: |
59 | idst->refresh_ts = jiffies; |
60 | return NULL; |
61 | } |
62 | |
63 | struct dst_entry *dst_cache_get(struct dst_cache *dst_cache) |
64 | { |
65 | if (!dst_cache->cache) |
66 | return NULL; |
67 | |
68 | return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache)); |
69 | } |
70 | EXPORT_SYMBOL_GPL(dst_cache_get); |
71 | |
72 | struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr) |
73 | { |
74 | struct dst_cache_pcpu *idst; |
75 | struct dst_entry *dst; |
76 | |
77 | if (!dst_cache->cache) |
78 | return NULL; |
79 | |
80 | idst = this_cpu_ptr(dst_cache->cache); |
81 | dst = dst_cache_per_cpu_get(dst_cache, idst); |
82 | if (!dst) |
83 | return NULL; |
84 | |
85 | *saddr = idst->in_saddr.s_addr; |
86 | return container_of(dst, struct rtable, dst); |
87 | } |
88 | EXPORT_SYMBOL_GPL(dst_cache_get_ip4); |
89 | |
90 | void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst, |
91 | __be32 saddr) |
92 | { |
93 | struct dst_cache_pcpu *idst; |
94 | |
95 | if (!dst_cache->cache) |
96 | return; |
97 | |
98 | idst = this_cpu_ptr(dst_cache->cache); |
99 | dst_cache_per_cpu_dst_set(dst_cache: idst, dst, cookie: 0); |
100 | idst->in_saddr.s_addr = saddr; |
101 | } |
102 | EXPORT_SYMBOL_GPL(dst_cache_set_ip4); |
103 | |
104 | #if IS_ENABLED(CONFIG_IPV6) |
105 | void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst, |
106 | const struct in6_addr *saddr) |
107 | { |
108 | struct dst_cache_pcpu *idst; |
109 | |
110 | if (!dst_cache->cache) |
111 | return; |
112 | |
113 | idst = this_cpu_ptr(dst_cache->cache); |
114 | dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst, |
115 | cookie: rt6_get_cookie(rt: (struct rt6_info *)dst)); |
116 | idst->in6_saddr = *saddr; |
117 | } |
118 | EXPORT_SYMBOL_GPL(dst_cache_set_ip6); |
119 | |
120 | struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache, |
121 | struct in6_addr *saddr) |
122 | { |
123 | struct dst_cache_pcpu *idst; |
124 | struct dst_entry *dst; |
125 | |
126 | if (!dst_cache->cache) |
127 | return NULL; |
128 | |
129 | idst = this_cpu_ptr(dst_cache->cache); |
130 | dst = dst_cache_per_cpu_get(dst_cache, idst); |
131 | if (!dst) |
132 | return NULL; |
133 | |
134 | *saddr = idst->in6_saddr; |
135 | return dst; |
136 | } |
137 | EXPORT_SYMBOL_GPL(dst_cache_get_ip6); |
138 | #endif |
139 | |
140 | int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp) |
141 | { |
142 | dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu, |
143 | gfp | __GFP_ZERO); |
144 | if (!dst_cache->cache) |
145 | return -ENOMEM; |
146 | |
147 | dst_cache_reset(dst_cache); |
148 | return 0; |
149 | } |
150 | EXPORT_SYMBOL_GPL(dst_cache_init); |
151 | |
152 | void dst_cache_destroy(struct dst_cache *dst_cache) |
153 | { |
154 | int i; |
155 | |
156 | if (!dst_cache->cache) |
157 | return; |
158 | |
159 | for_each_possible_cpu(i) |
160 | dst_release(per_cpu_ptr(dst_cache->cache, i)->dst); |
161 | |
162 | free_percpu(pdata: dst_cache->cache); |
163 | } |
164 | EXPORT_SYMBOL_GPL(dst_cache_destroy); |
165 | |
166 | void dst_cache_reset_now(struct dst_cache *dst_cache) |
167 | { |
168 | int i; |
169 | |
170 | if (!dst_cache->cache) |
171 | return; |
172 | |
173 | dst_cache->reset_ts = jiffies; |
174 | for_each_possible_cpu(i) { |
175 | struct dst_cache_pcpu *idst = per_cpu_ptr(dst_cache->cache, i); |
176 | struct dst_entry *dst = idst->dst; |
177 | |
178 | idst->cookie = 0; |
179 | idst->dst = NULL; |
180 | dst_release(dst); |
181 | } |
182 | } |
183 | EXPORT_SYMBOL_GPL(dst_cache_reset_now); |
184 | |