cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

dst_cache.c (3943B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * net/core/dst_cache.c - dst entry cache
      4 *
      5 * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com>
      6 */
      7
      8#include <linux/kernel.h>
      9#include <linux/percpu.h>
     10#include <net/dst_cache.h>
     11#include <net/route.h>
     12#if IS_ENABLED(CONFIG_IPV6)
     13#include <net/ip6_fib.h>
     14#endif
     15#include <uapi/linux/in.h>
     16
     17struct dst_cache_pcpu {
     18	unsigned long refresh_ts;
     19	struct dst_entry *dst;
     20	u32 cookie;
     21	union {
     22		struct in_addr in_saddr;
     23		struct in6_addr in6_saddr;
     24	};
     25};
     26
     27static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache,
     28				      struct dst_entry *dst, u32 cookie)
     29{
     30	dst_release(dst_cache->dst);
     31	if (dst)
     32		dst_hold(dst);
     33
     34	dst_cache->cookie = cookie;
     35	dst_cache->dst = dst;
     36}
     37
     38static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,
     39					       struct dst_cache_pcpu *idst)
     40{
     41	struct dst_entry *dst;
     42
     43	dst = idst->dst;
     44	if (!dst)
     45		goto fail;
     46
     47	/* the cache already hold a dst reference; it can't go away */
     48	dst_hold(dst);
     49
     50	if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) ||
     51		     (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) {
     52		dst_cache_per_cpu_dst_set(idst, NULL, 0);
     53		dst_release(dst);
     54		goto fail;
     55	}
     56	return dst;
     57
     58fail:
     59	idst->refresh_ts = jiffies;
     60	return NULL;
     61}
     62
     63struct dst_entry *dst_cache_get(struct dst_cache *dst_cache)
     64{
     65	if (!dst_cache->cache)
     66		return NULL;
     67
     68	return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));
     69}
     70EXPORT_SYMBOL_GPL(dst_cache_get);
     71
     72struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr)
     73{
     74	struct dst_cache_pcpu *idst;
     75	struct dst_entry *dst;
     76
     77	if (!dst_cache->cache)
     78		return NULL;
     79
     80	idst = this_cpu_ptr(dst_cache->cache);
     81	dst = dst_cache_per_cpu_get(dst_cache, idst);
     82	if (!dst)
     83		return NULL;
     84
     85	*saddr = idst->in_saddr.s_addr;
     86	return container_of(dst, struct rtable, dst);
     87}
     88EXPORT_SYMBOL_GPL(dst_cache_get_ip4);
     89
     90void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
     91		       __be32 saddr)
     92{
     93	struct dst_cache_pcpu *idst;
     94
     95	if (!dst_cache->cache)
     96		return;
     97
     98	idst = this_cpu_ptr(dst_cache->cache);
     99	dst_cache_per_cpu_dst_set(idst, dst, 0);
    100	idst->in_saddr.s_addr = saddr;
    101}
    102EXPORT_SYMBOL_GPL(dst_cache_set_ip4);
    103
    104#if IS_ENABLED(CONFIG_IPV6)
    105void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
    106		       const struct in6_addr *saddr)
    107{
    108	struct dst_cache_pcpu *idst;
    109
    110	if (!dst_cache->cache)
    111		return;
    112
    113	idst = this_cpu_ptr(dst_cache->cache);
    114	dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst,
    115				  rt6_get_cookie((struct rt6_info *)dst));
    116	idst->in6_saddr = *saddr;
    117}
    118EXPORT_SYMBOL_GPL(dst_cache_set_ip6);
    119
    120struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
    121				    struct in6_addr *saddr)
    122{
    123	struct dst_cache_pcpu *idst;
    124	struct dst_entry *dst;
    125
    126	if (!dst_cache->cache)
    127		return NULL;
    128
    129	idst = this_cpu_ptr(dst_cache->cache);
    130	dst = dst_cache_per_cpu_get(dst_cache, idst);
    131	if (!dst)
    132		return NULL;
    133
    134	*saddr = idst->in6_saddr;
    135	return dst;
    136}
    137EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
    138#endif
    139
    140int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
    141{
    142	dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
    143					    gfp | __GFP_ZERO);
    144	if (!dst_cache->cache)
    145		return -ENOMEM;
    146
    147	dst_cache_reset(dst_cache);
    148	return 0;
    149}
    150EXPORT_SYMBOL_GPL(dst_cache_init);
    151
    152void dst_cache_destroy(struct dst_cache *dst_cache)
    153{
    154	int i;
    155
    156	if (!dst_cache->cache)
    157		return;
    158
    159	for_each_possible_cpu(i)
    160		dst_release(per_cpu_ptr(dst_cache->cache, i)->dst);
    161
    162	free_percpu(dst_cache->cache);
    163}
    164EXPORT_SYMBOL_GPL(dst_cache_destroy);
    165
    166void dst_cache_reset_now(struct dst_cache *dst_cache)
    167{
    168	int i;
    169
    170	if (!dst_cache->cache)
    171		return;
    172
    173	dst_cache->reset_ts = jiffies;
    174	for_each_possible_cpu(i) {
    175		struct dst_cache_pcpu *idst = per_cpu_ptr(dst_cache->cache, i);
    176		struct dst_entry *dst = idst->dst;
    177
    178		idst->cookie = 0;
    179		idst->dst = NULL;
    180		dst_release(dst);
    181	}
    182}
    183EXPORT_SYMBOL_GPL(dst_cache_reset_now);