437 lines
11 KiB
C
437 lines
11 KiB
C
/*
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* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/log2.h>
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#include <linux/jhash.h>
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#include <linux/netlink.h>
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#include <linux/vmalloc.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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#define NFT_HASH_MIN_SIZE 4UL
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struct nft_hash {
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struct nft_hash_table __rcu *tbl;
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};
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struct nft_hash_table {
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unsigned int size;
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struct nft_hash_elem __rcu *buckets[];
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};
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struct nft_hash_elem {
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struct nft_hash_elem __rcu *next;
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struct nft_data key;
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struct nft_data data[];
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};
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#define nft_hash_for_each_entry(i, head) \
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for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
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#define nft_hash_for_each_entry_rcu(i, head) \
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for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))
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static u32 nft_hash_rnd __read_mostly;
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static bool nft_hash_rnd_initted __read_mostly;
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static unsigned int nft_hash_data(const struct nft_data *data,
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unsigned int hsize, unsigned int len)
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{
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unsigned int h;
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h = jhash(data->data, len, nft_hash_rnd);
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return h & (hsize - 1);
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}
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static bool nft_hash_lookup(const struct nft_set *set,
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const struct nft_data *key,
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struct nft_data *data)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
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const struct nft_hash_elem *he;
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unsigned int h;
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h = nft_hash_data(key, tbl->size, set->klen);
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nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
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if (nft_data_cmp(&he->key, key, set->klen))
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continue;
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(data, he->data);
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return true;
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}
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return false;
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}
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static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
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{
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if (is_vmalloc_addr(tbl))
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vfree(tbl);
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else
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kfree(tbl);
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}
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static unsigned int nft_hash_tbl_size(unsigned int nelem)
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{
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return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE);
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}
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static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
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{
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struct nft_hash_table *tbl;
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size_t size;
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size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
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tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN);
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if (tbl == NULL)
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tbl = vzalloc(size);
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if (tbl == NULL)
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return NULL;
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tbl->size = nbuckets;
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return tbl;
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}
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static void nft_hash_chain_unzip(const struct nft_set *set,
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const struct nft_hash_table *ntbl,
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struct nft_hash_table *tbl, unsigned int n)
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{
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struct nft_hash_elem *he, *last, *next;
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unsigned int h;
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he = nft_dereference(tbl->buckets[n]);
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if (he == NULL)
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return;
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h = nft_hash_data(&he->key, ntbl->size, set->klen);
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/* Find last element of first chain hashing to bucket h */
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last = he;
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nft_hash_for_each_entry(he, he->next) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
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break;
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last = he;
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}
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/* Unlink first chain from the old table */
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RCU_INIT_POINTER(tbl->buckets[n], last->next);
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/* If end of chain reached, done */
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if (he == NULL)
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return;
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/* Find first element of second chain hashing to bucket h */
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next = NULL;
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nft_hash_for_each_entry(he, he->next) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
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continue;
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next = he;
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break;
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}
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/* Link the two chains */
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RCU_INIT_POINTER(last->next, next);
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}
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static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv)
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{
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struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
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struct nft_hash_elem *he;
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unsigned int i, h;
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bool complete;
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ntbl = nft_hash_tbl_alloc(tbl->size * 2);
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if (ntbl == NULL)
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return -ENOMEM;
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/* Link new table's buckets to first element in the old table
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* hashing to the new bucket.
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*/
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for (i = 0; i < ntbl->size; i++) {
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h = i < tbl->size ? i : i - tbl->size;
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nft_hash_for_each_entry(he, tbl->buckets[h]) {
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if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
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continue;
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RCU_INIT_POINTER(ntbl->buckets[i], he);
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break;
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}
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}
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/* Publish new table */
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rcu_assign_pointer(priv->tbl, ntbl);
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/* Unzip interleaved hash chains */
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do {
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/* Wait for readers to use new table/unzipped chains */
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synchronize_rcu();
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complete = true;
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for (i = 0; i < tbl->size; i++) {
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nft_hash_chain_unzip(set, ntbl, tbl, i);
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if (tbl->buckets[i] != NULL)
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complete = false;
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}
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} while (!complete);
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nft_hash_tbl_free(tbl);
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return 0;
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}
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static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv)
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{
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struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
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struct nft_hash_elem __rcu **pprev;
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unsigned int i;
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ntbl = nft_hash_tbl_alloc(tbl->size / 2);
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if (ntbl == NULL)
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return -ENOMEM;
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for (i = 0; i < ntbl->size; i++) {
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ntbl->buckets[i] = tbl->buckets[i];
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for (pprev = &ntbl->buckets[i]; *pprev != NULL;
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pprev = &nft_dereference(*pprev)->next)
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;
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RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
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}
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/* Publish new table */
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rcu_assign_pointer(priv->tbl, ntbl);
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synchronize_rcu();
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nft_hash_tbl_free(tbl);
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return 0;
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}
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static int nft_hash_insert(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem *he;
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unsigned int size, h;
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if (elem->flags != 0)
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return -EINVAL;
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size = sizeof(*he);
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if (set->flags & NFT_SET_MAP)
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size += sizeof(he->data[0]);
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he = kzalloc(size, GFP_KERNEL);
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if (he == NULL)
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return -ENOMEM;
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nft_data_copy(&he->key, &elem->key);
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(he->data, &elem->data);
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h = nft_hash_data(&he->key, tbl->size, set->klen);
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RCU_INIT_POINTER(he->next, tbl->buckets[h]);
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rcu_assign_pointer(tbl->buckets[h], he);
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/* Expand table when exceeding 75% load */
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if (set->nelems + 1 > tbl->size / 4 * 3)
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nft_hash_tbl_expand(set, priv);
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return 0;
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}
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static void nft_hash_elem_destroy(const struct nft_set *set,
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struct nft_hash_elem *he)
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{
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nft_data_uninit(&he->key, NFT_DATA_VALUE);
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if (set->flags & NFT_SET_MAP)
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nft_data_uninit(he->data, set->dtype);
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kfree(he);
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}
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static void nft_hash_remove(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem *he, __rcu **pprev;
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pprev = elem->cookie;
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he = nft_dereference((*pprev));
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RCU_INIT_POINTER(*pprev, he->next);
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synchronize_rcu();
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kfree(he);
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/* Shrink table beneath 30% load */
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if (set->nelems - 1 < tbl->size * 3 / 10 &&
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tbl->size > NFT_HASH_MIN_SIZE)
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nft_hash_tbl_shrink(set, priv);
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}
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static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem __rcu * const *pprev;
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struct nft_hash_elem *he;
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unsigned int h;
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h = nft_hash_data(&elem->key, tbl->size, set->klen);
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pprev = &tbl->buckets[h];
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nft_hash_for_each_entry(he, tbl->buckets[h]) {
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if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
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pprev = &he->next;
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continue;
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}
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elem->cookie = (void *)pprev;
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elem->flags = 0;
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(&elem->data, he->data);
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return 0;
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}
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return -ENOENT;
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}
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static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
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struct nft_set_iter *iter)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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const struct nft_hash_elem *he;
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struct nft_set_elem elem;
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unsigned int i;
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for (i = 0; i < tbl->size; i++) {
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nft_hash_for_each_entry(he, tbl->buckets[i]) {
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if (iter->count < iter->skip)
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goto cont;
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memcpy(&elem.key, &he->key, sizeof(elem.key));
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if (set->flags & NFT_SET_MAP)
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memcpy(&elem.data, he->data, sizeof(elem.data));
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elem.flags = 0;
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iter->err = iter->fn(ctx, set, iter, &elem);
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if (iter->err < 0)
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return;
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cont:
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iter->count++;
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}
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}
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}
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static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
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{
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return sizeof(struct nft_hash);
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}
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static int nft_hash_init(const struct nft_set *set,
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const struct nft_set_desc *desc,
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const struct nlattr * const tb[])
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{
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struct nft_hash *priv = nft_set_priv(set);
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struct nft_hash_table *tbl;
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unsigned int size;
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if (unlikely(!nft_hash_rnd_initted)) {
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get_random_bytes(&nft_hash_rnd, 4);
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nft_hash_rnd_initted = true;
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}
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size = NFT_HASH_MIN_SIZE;
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if (desc->size)
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size = nft_hash_tbl_size(desc->size);
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tbl = nft_hash_tbl_alloc(size);
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if (tbl == NULL)
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return -ENOMEM;
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RCU_INIT_POINTER(priv->tbl, tbl);
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return 0;
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}
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static void nft_hash_destroy(const struct nft_set *set)
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{
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const struct nft_hash *priv = nft_set_priv(set);
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const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
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struct nft_hash_elem *he, *next;
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unsigned int i;
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for (i = 0; i < tbl->size; i++) {
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for (he = nft_dereference(tbl->buckets[i]); he != NULL;
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he = next) {
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next = nft_dereference(he->next);
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nft_hash_elem_destroy(set, he);
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}
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}
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kfree(tbl);
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}
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static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
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struct nft_set_estimate *est)
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{
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unsigned int esize;
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esize = sizeof(struct nft_hash_elem);
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if (features & NFT_SET_MAP)
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esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]);
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if (desc->size) {
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est->size = sizeof(struct nft_hash) +
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nft_hash_tbl_size(desc->size) *
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sizeof(struct nft_hash_elem *) +
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desc->size * esize;
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} else {
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/* Resizing happens when the load drops below 30% or goes
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* above 75%. The average of 52.5% load (approximated by 50%)
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* is used for the size estimation of the hash buckets,
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* meaning we calculate two buckets per element.
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*/
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est->size = esize + 2 * sizeof(struct nft_hash_elem *);
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}
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est->class = NFT_SET_CLASS_O_1;
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return true;
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}
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static struct nft_set_ops nft_hash_ops __read_mostly = {
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.privsize = nft_hash_privsize,
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.estimate = nft_hash_estimate,
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.init = nft_hash_init,
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.destroy = nft_hash_destroy,
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.get = nft_hash_get,
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.insert = nft_hash_insert,
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.remove = nft_hash_remove,
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.lookup = nft_hash_lookup,
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.walk = nft_hash_walk,
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.features = NFT_SET_MAP,
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.owner = THIS_MODULE,
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};
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static int __init nft_hash_module_init(void)
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{
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return nft_register_set(&nft_hash_ops);
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}
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static void __exit nft_hash_module_exit(void)
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{
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nft_unregister_set(&nft_hash_ops);
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}
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module_init(nft_hash_module_init);
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module_exit(nft_hash_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_SET();
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