/* * net/core/dst_cache.c - dst entry cache * * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include <linux/kernel.h>#include <linux/percpu.h>#include <net/dst_cache.h>#include <net/route.h>#if IS_ENABLED(CONFIG_IPV6)#include <net/ip6_fib.h>#endif#include <uapi/linux/in.h> struct dst_cache_pcpu {	unsigned long refresh_ts;	struct dst_entry *dst;	u32 cookie;	union {		struct in_addr in_saddr;		struct in6_addr in6_saddr;	};}; static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache,				      struct dst_entry *dst, u32 cookie){	dst_release(dst_cache->dst);	if (dst)		dst_hold(dst); 	dst_cache->cookie = cookie;	dst_cache->dst = dst;} static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,					       struct dst_cache_pcpu *idst){	struct dst_entry *dst; 	dst = idst->dst;	if (!dst)		goto fail; 	/* the cache already hold a dst reference; it can't go away */	dst_hold(dst); 	if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) ||		     (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) {		dst_cache_per_cpu_dst_set(idst, NULL, 0);		dst_release(dst);		goto fail;	}	return dst; fail:	idst->refresh_ts = jiffies;	return NULL;} struct dst_entry *dst_cache_get(struct dst_cache *dst_cache){	if (!dst_cache->cache)		return NULL; 	return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));}EXPORT_SYMBOL_GPL(dst_cache_get); struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr){	struct dst_cache_pcpu *idst;	struct dst_entry *dst; 	if (!dst_cache->cache)		return NULL; 	idst = this_cpu_ptr(dst_cache->cache);	dst = dst_cache_per_cpu_get(dst_cache, idst);	if (!dst)		return NULL; 	*saddr = idst->in_saddr.s_addr;	return container_of(dst, struct rtable, dst);}EXPORT_SYMBOL_GPL(dst_cache_get_ip4); void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,		       __be32 saddr){	struct dst_cache_pcpu *idst; 	if (!dst_cache->cache)		return; 	idst = this_cpu_ptr(dst_cache->cache);	dst_cache_per_cpu_dst_set(idst, dst, 0);	idst->in_saddr.s_addr = saddr;}EXPORT_SYMBOL_GPL(dst_cache_set_ip4); #if IS_ENABLED(CONFIG_IPV6)void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,		       const struct in6_addr *addr){	struct dst_cache_pcpu *idst; 	if (!dst_cache->cache)		return; 	idst = this_cpu_ptr(dst_cache->cache);	dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst,				  rt6_get_cookie((struct rt6_info *)dst));	idst->in6_saddr = *addr;}EXPORT_SYMBOL_GPL(dst_cache_set_ip6); struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,				    struct in6_addr *saddr){	struct dst_cache_pcpu *idst;	struct dst_entry *dst; 	if (!dst_cache->cache)		return NULL; 	idst = this_cpu_ptr(dst_cache->cache);	dst = dst_cache_per_cpu_get(dst_cache, idst);	if (!dst)		return NULL; 	*saddr = idst->in6_saddr;	return dst;}EXPORT_SYMBOL_GPL(dst_cache_get_ip6);#endif int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp){	dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,					    gfp | __GFP_ZERO);	if (!dst_cache->cache)		return -ENOMEM; 	dst_cache_reset(dst_cache);	return 0;}EXPORT_SYMBOL_GPL(dst_cache_init); void dst_cache_destroy(struct dst_cache *dst_cache){	int i; 	if (!dst_cache->cache)		return; 	for_each_possible_cpu(i)		dst_release(per_cpu_ptr(dst_cache->cache, i)->dst); 	free_percpu(dst_cache->cache);}EXPORT_SYMBOL_GPL(dst_cache_destroy);