include/net/dst_cache.h

   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 *addr);
  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 do 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         dst_cache->reset_ts = jiffies;
  80 }
  81
  82 /**
  83  *      dst_cache_init - initialize the cache, allocating the required storage
  84  *      @dst_cache: the cache
  85  *      @gfp: allocation flags
  86  */
  87 int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp);
  88
  89 /**
  90  *      dst_cache_destroy - empty the cache and free the allocated storage
  91  *      @dst_cache: the cache
  92  *
  93  *      No synchronization is enforced: it must be called only when the cache
  94  *      is unsed.
  95  */
  96 void dst_cache_destroy(struct dst_cache *dst_cache);
  97
  98 #endif