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_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(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 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(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) 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); 119 120 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(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