/* SPDX-License-Identifier: GPL-2.0 */#ifndef _NET_DST_CACHE_H#define _NET_DST_CACHE_H #include <linux/jiffies.h>#include <net/dst.h>#if IS_ENABLED(CONFIG_IPV6)#include <net/ip6_fib.h>#endif struct dst_cache {	struct dst_cache_pcpu __percpu *cache;	unsigned long reset_ts;}; /** *	dst_cache_get - perform cache lookup *	@dst_cache: the cache * *	The caller should use dst_cache_get_ip4() if it need to retrieve the *	source address to be used when xmitting to the cached dst. *	local BH must be disabled. */struct dst_entry *dst_cache_get(struct dst_cache *dst_cache); /** *	dst_cache_get_ip4 - perform cache lookup and fetch ipv4 source address *	@dst_cache: the cache *	@saddr: return value for the retrieved source address * *	local BH must be disabled. */struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr); /** *	dst_cache_set_ip4 - store the ipv4 dst into the cache *	@dst_cache: the cache *	@dst: the entry to be cached *	@saddr: the source address to be stored inside the cache * *	local BH must be disabled. */void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,		       __be32 saddr); #if IS_ENABLED(CONFIG_IPV6) /** *	dst_cache_set_ip6 - store the ipv6 dst into the cache *	@dst_cache: the cache *	@dst: the entry to be cached *	@saddr: the source address to be stored inside the cache * *	local BH must be disabled. */void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,		       const struct in6_addr *saddr); /** *	dst_cache_get_ip6 - perform cache lookup and fetch ipv6 source address *	@dst_cache: the cache *	@saddr: return value for the retrieved source address * *	local BH must be disabled. */struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,				    struct in6_addr *saddr);#endif /** *	dst_cache_reset - invalidate the cache contents *	@dst_cache: the cache * *	This does not free the cached dst to avoid races and contentions. *	the dst will be freed on later cache lookup. */static inline void dst_cache_reset(struct dst_cache *dst_cache){	WRITE_ONCE(dst_cache->reset_ts, jiffies);} /** *	dst_cache_reset_now - invalidate the cache contents immediately *	@dst_cache: the cache * *	The caller must be sure there are no concurrent users, as this frees *	all dst_cache users immediately, rather than waiting for the next *	per-cpu usage like dst_cache_reset does. Most callers should use the *	higher speed lazily-freed dst_cache_reset function instead. */void dst_cache_reset_now(struct dst_cache *dst_cache); /** *	dst_cache_init - initialize the cache, allocating the required storage *	@dst_cache: the cache *	@gfp: allocation flags */int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp); /** *	dst_cache_destroy - empty the cache and free the allocated storage *	@dst_cache: the cache * *	No synchronization is enforced: it must be called only when the cache *	is unused. */void dst_cache_destroy(struct dst_cache *dst_cache); #endif