swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: b562e44f507e863c6792946e4e1b1449fbbac85d authored by Linus Torvalds on 14 March 2016, 04:28:54 UTC
Linux 4.5
Linux 4.5
Tip revision: b562e44
nft_hash.c
/*
* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/log2.h>
#include <linux/jhash.h>
#include <linux/netlink.h>
#include <linux/workqueue.h>
#include <linux/rhashtable.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
/* We target a hash table size of 4, element hint is 75% of final size */
#define NFT_HASH_ELEMENT_HINT 3
struct nft_hash {
struct rhashtable ht;
struct delayed_work gc_work;
};
struct nft_hash_elem {
struct rhash_head node;
struct nft_set_ext ext;
};
struct nft_hash_cmp_arg {
const struct nft_set *set;
const u32 *key;
u8 genmask;
};
static const struct rhashtable_params nft_hash_params;
static inline u32 nft_hash_key(const void *data, u32 len, u32 seed)
{
const struct nft_hash_cmp_arg *arg = data;
return jhash(arg->key, len, seed);
}
static inline u32 nft_hash_obj(const void *data, u32 len, u32 seed)
{
const struct nft_hash_elem *he = data;
return jhash(nft_set_ext_key(&he->ext), len, seed);
}
static inline int nft_hash_cmp(struct rhashtable_compare_arg *arg,
const void *ptr)
{
const struct nft_hash_cmp_arg *x = arg->key;
const struct nft_hash_elem *he = ptr;
if (memcmp(nft_set_ext_key(&he->ext), x->key, x->set->klen))
return 1;
if (nft_set_elem_expired(&he->ext))
return 1;
if (!nft_set_elem_active(&he->ext, x->genmask))
return 1;
return 0;
}
static bool nft_hash_lookup(const struct nft_set *set, const u32 *key,
const struct nft_set_ext **ext)
{
struct nft_hash *priv = nft_set_priv(set);
const struct nft_hash_elem *he;
struct nft_hash_cmp_arg arg = {
.genmask = nft_genmask_cur(read_pnet(&set->pnet)),
.set = set,
.key = key,
};
he = rhashtable_lookup_fast(&priv->ht, &arg, nft_hash_params);
if (he != NULL)
*ext = &he->ext;
return !!he;
}
static bool nft_hash_update(struct nft_set *set, const u32 *key,
void *(*new)(struct nft_set *,
const struct nft_expr *,
struct nft_regs *regs),
const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_set_ext **ext)
{
struct nft_hash *priv = nft_set_priv(set);
struct nft_hash_elem *he;
struct nft_hash_cmp_arg arg = {
.genmask = NFT_GENMASK_ANY,
.set = set,
.key = key,
};
he = rhashtable_lookup_fast(&priv->ht, &arg, nft_hash_params);
if (he != NULL)
goto out;
he = new(set, expr, regs);
if (he == NULL)
goto err1;
if (rhashtable_lookup_insert_key(&priv->ht, &arg, &he->node,
nft_hash_params))
goto err2;
out:
*ext = &he->ext;
return true;
err2:
nft_set_elem_destroy(set, he);
err1:
return false;
}
static int nft_hash_insert(const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_hash *priv = nft_set_priv(set);
struct nft_hash_elem *he = elem->priv;
struct nft_hash_cmp_arg arg = {
.genmask = nft_genmask_next(read_pnet(&set->pnet)),
.set = set,
.key = elem->key.val.data,
};
return rhashtable_lookup_insert_key(&priv->ht, &arg, &he->node,
nft_hash_params);
}
static void nft_hash_activate(const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_hash_elem *he = elem->priv;
nft_set_elem_change_active(set, &he->ext);
nft_set_elem_clear_busy(&he->ext);
}
static void *nft_hash_deactivate(const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_hash *priv = nft_set_priv(set);
struct nft_hash_elem *he;
struct nft_hash_cmp_arg arg = {
.genmask = nft_genmask_next(read_pnet(&set->pnet)),
.set = set,
.key = elem->key.val.data,
};
rcu_read_lock();
he = rhashtable_lookup_fast(&priv->ht, &arg, nft_hash_params);
if (he != NULL) {
if (!nft_set_elem_mark_busy(&he->ext))
nft_set_elem_change_active(set, &he->ext);
else
he = NULL;
}
rcu_read_unlock();
return he;
}
static void nft_hash_remove(const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_hash *priv = nft_set_priv(set);
struct nft_hash_elem *he = elem->priv;
rhashtable_remove_fast(&priv->ht, &he->node, nft_hash_params);
}
static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
struct nft_set_iter *iter)
{
struct nft_hash *priv = nft_set_priv(set);
struct nft_hash_elem *he;
struct rhashtable_iter hti;
struct nft_set_elem elem;
u8 genmask = nft_genmask_cur(read_pnet(&set->pnet));
int err;
err = rhashtable_walk_init(&priv->ht, &hti);
iter->err = err;
if (err)
return;
err = rhashtable_walk_start(&hti);
if (err && err != -EAGAIN) {
iter->err = err;
goto out;
}
while ((he = rhashtable_walk_next(&hti))) {
if (IS_ERR(he)) {
err = PTR_ERR(he);
if (err != -EAGAIN) {
iter->err = err;
goto out;
}
continue;
}
if (iter->count < iter->skip)
goto cont;
if (nft_set_elem_expired(&he->ext))
goto cont;
if (!nft_set_elem_active(&he->ext, genmask))
goto cont;
elem.priv = he;
iter->err = iter->fn(ctx, set, iter, &elem);
if (iter->err < 0)
goto out;
cont:
iter->count++;
}
out:
rhashtable_walk_stop(&hti);
rhashtable_walk_exit(&hti);
}
static void nft_hash_gc(struct work_struct *work)
{
struct nft_set *set;
struct nft_hash_elem *he;
struct nft_hash *priv;
struct nft_set_gc_batch *gcb = NULL;
struct rhashtable_iter hti;
int err;
priv = container_of(work, struct nft_hash, gc_work.work);
set = nft_set_container_of(priv);
err = rhashtable_walk_init(&priv->ht, &hti);
if (err)
goto schedule;
err = rhashtable_walk_start(&hti);
if (err && err != -EAGAIN)
goto out;
while ((he = rhashtable_walk_next(&hti))) {
if (IS_ERR(he)) {
if (PTR_ERR(he) != -EAGAIN)
goto out;
continue;
}
if (!nft_set_elem_expired(&he->ext))
continue;
if (nft_set_elem_mark_busy(&he->ext))
continue;
gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
if (gcb == NULL)
goto out;
rhashtable_remove_fast(&priv->ht, &he->node, nft_hash_params);
atomic_dec(&set->nelems);
nft_set_gc_batch_add(gcb, he);
}
out:
rhashtable_walk_stop(&hti);
rhashtable_walk_exit(&hti);
nft_set_gc_batch_complete(gcb);
schedule:
queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
nft_set_gc_interval(set));
}
static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
{
return sizeof(struct nft_hash);
}
static const struct rhashtable_params nft_hash_params = {
.head_offset = offsetof(struct nft_hash_elem, node),
.hashfn = nft_hash_key,
.obj_hashfn = nft_hash_obj,
.obj_cmpfn = nft_hash_cmp,
.automatic_shrinking = true,
};
static int nft_hash_init(const struct nft_set *set,
const struct nft_set_desc *desc,
const struct nlattr * const tb[])
{
struct nft_hash *priv = nft_set_priv(set);
struct rhashtable_params params = nft_hash_params;
int err;
params.nelem_hint = desc->size ?: NFT_HASH_ELEMENT_HINT;
params.key_len = set->klen;
err = rhashtable_init(&priv->ht, ¶ms);
if (err < 0)
return err;
INIT_DEFERRABLE_WORK(&priv->gc_work, nft_hash_gc);
if (set->flags & NFT_SET_TIMEOUT)
queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
nft_set_gc_interval(set));
return 0;
}
static void nft_hash_elem_destroy(void *ptr, void *arg)
{
nft_set_elem_destroy((const struct nft_set *)arg, ptr);
}
static void nft_hash_destroy(const struct nft_set *set)
{
struct nft_hash *priv = nft_set_priv(set);
cancel_delayed_work_sync(&priv->gc_work);
rhashtable_free_and_destroy(&priv->ht, nft_hash_elem_destroy,
(void *)set);
}
static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
struct nft_set_estimate *est)
{
unsigned int esize;
esize = sizeof(struct nft_hash_elem);
if (desc->size) {
est->size = sizeof(struct nft_hash) +
roundup_pow_of_two(desc->size * 4 / 3) *
sizeof(struct nft_hash_elem *) +
desc->size * esize;
} else {
/* Resizing happens when the load drops below 30% or goes
* above 75%. The average of 52.5% load (approximated by 50%)
* is used for the size estimation of the hash buckets,
* meaning we calculate two buckets per element.
*/
est->size = esize + 2 * sizeof(struct nft_hash_elem *);
}
est->class = NFT_SET_CLASS_O_1;
return true;
}
static struct nft_set_ops nft_hash_ops __read_mostly = {
.privsize = nft_hash_privsize,
.elemsize = offsetof(struct nft_hash_elem, ext),
.estimate = nft_hash_estimate,
.init = nft_hash_init,
.destroy = nft_hash_destroy,
.insert = nft_hash_insert,
.activate = nft_hash_activate,
.deactivate = nft_hash_deactivate,
.remove = nft_hash_remove,
.lookup = nft_hash_lookup,
.update = nft_hash_update,
.walk = nft_hash_walk,
.features = NFT_SET_MAP | NFT_SET_TIMEOUT,
.owner = THIS_MODULE,
};
static int __init nft_hash_module_init(void)
{
return nft_register_set(&nft_hash_ops);
}
static void __exit nft_hash_module_exit(void)
{
nft_unregister_set(&nft_hash_ops);
}
module_init(nft_hash_module_init);
module_exit(nft_hash_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_SET();