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
dst_cache_per_cpu_dst_set(struct dst_cache_pcpu * dst_cache,struct dst_entry * dst,u32 cookie)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_cache->dst);
31 if (dst)
32 dst_hold(dst);
33
34 dst_cache->cookie = cookie;
35 dst_cache->dst = dst;
36 }
37
dst_cache_per_cpu_get(struct dst_cache * dst_cache,struct dst_cache_pcpu * idst)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(idst, NULL, 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
dst_cache_get(struct dst_cache * dst_cache)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
dst_cache_get_ip4(struct dst_cache * dst_cache,__be32 * saddr)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
dst_cache_set_ip4(struct dst_cache * dst_cache,struct dst_entry * dst,__be32 saddr)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(idst, dst, 0);
100 idst->in_saddr.s_addr = saddr;
101 }
102 EXPORT_SYMBOL_GPL(dst_cache_set_ip4);
103
104 #if IS_ENABLED(CONFIG_IPV6)
dst_cache_set_ip6(struct dst_cache * dst_cache,struct dst_entry * dst,const struct in6_addr * saddr)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 rt6_get_cookie((struct rt6_info *)dst));
116 idst->in6_saddr = *saddr;
117 }
118 EXPORT_SYMBOL_GPL(dst_cache_set_ip6);
119
dst_cache_get_ip6(struct dst_cache * dst_cache,struct in6_addr * saddr)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
dst_cache_init(struct dst_cache * dst_cache,gfp_t gfp)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
dst_cache_destroy(struct dst_cache * dst_cache)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(dst_cache->cache);
163 }
164 EXPORT_SYMBOL_GPL(dst_cache_destroy);
165
dst_cache_reset_now(struct dst_cache * dst_cache)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