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/*
* 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>
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
static inline u32 rt6_get_cookie(const struct rt6_info *rt)
{
if ((unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
rt = (struct rt6_info *)(rt->dst.from);
return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
}
#endif
#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));
}
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);
}
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;
}
#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;
}
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;
}
#endif
int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
BUG_ON(gfp & GFP_ATOMIC);
dst_cache->cache = alloc_percpu(struct dst_cache_pcpu);
#else
dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
gfp | __GFP_ZERO);
#endif
if (!dst_cache->cache)
return -ENOMEM;
dst_cache_reset(dst_cache);
return 0;
}
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);
}
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