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 WRITE_ONCE(dst_cache->reset_ts, jiffies); 80 } 81 82 /** 83 * dst_cache_reset_now - invalidate the cache contents immediately 84 * @dst_cache: the cache 85 * 86 * The caller must be sure there are no concurrent users, as this frees 87 * all dst_cache users immediately, rather than waiting for the next 88 * per-cpu usage like dst_cache_reset does. Most callers should use the 89 * higher speed lazily-freed dst_cache_reset function instead. 90 */ 91 void dst_cache_reset_now(struct dst_cache *dst_cache); 92 93 /** 94 * dst_cache_init - initialize the cache, allocating the required storage 95 * @dst_cache: the cache 96 * @gfp: allocation flags 97 */ 98 int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp); 99 100 /** 101 * dst_cache_destroy - empty the cache and free the allocated storage 102 * @dst_cache: the cache 103 * 104 * No synchronization is enforced: it must be called only when the cache 105 * is unsed. 106 */ 107 void dst_cache_destroy(struct dst_cache *dst_cache); 108 109 #endif 110