1 files changed, 433 insertions, 0 deletions
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
new file mode 100644
index 00000000000..4080ed6a072
--- /dev/null
+++ b/net/netfilter/nft_hash.c
@@ -0,0 +1,433 @@
+/*
+ * 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/vmalloc.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+
+#define NFT_HASH_MIN_SIZE	4UL
+
+struct nft_hash {
+	struct nft_hash_table __rcu	*tbl;
+};
+
+struct nft_hash_table {
+	unsigned int			size;
+	struct nft_hash_elem __rcu	*buckets[];
+};
+
+struct nft_hash_elem {
+	struct nft_hash_elem __rcu	*next;
+	struct nft_data			key;
+	struct nft_data			data[];
+};
+
+#define nft_hash_for_each_entry(i, head) \
+	for (i = nft_dereference(head); i != NULL; i = nft_dereference(i->next))
+#define nft_hash_for_each_entry_rcu(i, head) \
+	for (i = rcu_dereference(head); i != NULL; i = rcu_dereference(i->next))
+
+static u32 nft_hash_rnd __read_mostly;
+static bool nft_hash_rnd_initted __read_mostly;
+
+static unsigned int nft_hash_data(const struct nft_data *data,
+				  unsigned int hsize, unsigned int len)
+{
+	unsigned int h;
+
+	h = jhash(data->data, len, nft_hash_rnd);
+	return h & (hsize - 1);
+}
+
+static bool nft_hash_lookup(const struct nft_set *set,
+			    const struct nft_data *key,
+			    struct nft_data *data)
+{
+	const struct nft_hash *priv = nft_set_priv(set);
+	const struct nft_hash_table *tbl = rcu_dereference(priv->tbl);
+	const struct nft_hash_elem *he;
+	unsigned int h;
+
+	h = nft_hash_data(key, tbl->size, set->klen);
+	nft_hash_for_each_entry_rcu(he, tbl->buckets[h]) {
+		if (nft_data_cmp(&he->key, key, set->klen))
+			continue;
+		if (set->flags & NFT_SET_MAP)
+			nft_data_copy(data, he->data);
+		return true;
+	}
+	return false;
+}
+
+static void nft_hash_tbl_free(const struct nft_hash_table *tbl)
+{
+	kvfree(tbl);
+}
+
+static unsigned int nft_hash_tbl_size(unsigned int nelem)
+{
+	return max(roundup_pow_of_two(nelem * 4 / 3), NFT_HASH_MIN_SIZE);
+}
+
+static struct nft_hash_table *nft_hash_tbl_alloc(unsigned int nbuckets)
+{
+	struct nft_hash_table *tbl;
+	size_t size;
+
+	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
+	tbl = kzalloc(size, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN);
+	if (tbl == NULL)
+		tbl = vzalloc(size);
+	if (tbl == NULL)
+		return NULL;
+	tbl->size = nbuckets;
+
+	return tbl;
+}
+
+static void nft_hash_chain_unzip(const struct nft_set *set,
+				 const struct nft_hash_table *ntbl,
+				 struct nft_hash_table *tbl, unsigned int n)
+{
+	struct nft_hash_elem *he, *last, *next;
+	unsigned int h;
+
+	he = nft_dereference(tbl->buckets[n]);
+	if (he == NULL)
+		return;
+	h = nft_hash_data(&he->key, ntbl->size, set->klen);
+
+	/* Find last element of first chain hashing to bucket h */
+	last = he;
+	nft_hash_for_each_entry(he, he->next) {
+		if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
+			break;
+		last = he;
+	}
+
+	/* Unlink first chain from the old table */
+	RCU_INIT_POINTER(tbl->buckets[n], last->next);
+
+	/* If end of chain reached, done */
+	if (he == NULL)
+		return;
+
+	/* Find first element of second chain hashing to bucket h */
+	next = NULL;
+	nft_hash_for_each_entry(he, he->next) {
+		if (nft_hash_data(&he->key, ntbl->size, set->klen) != h)
+			continue;
+		next = he;
+		break;
+	}
+
+	/* Link the two chains */
+	RCU_INIT_POINTER(last->next, next);
+}
+
+static int nft_hash_tbl_expand(const struct nft_set *set, struct nft_hash *priv)
+{
+	struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
+	struct nft_hash_elem *he;
+	unsigned int i, h;
+	bool complete;
+
+	ntbl = nft_hash_tbl_alloc(tbl->size * 2);
+	if (ntbl == NULL)
+		return -ENOMEM;
+
+	/* Link new table's buckets to first element in the old table
+	 * hashing to the new bucket.
+	 */
+	for (i = 0; i < ntbl->size; i++) {
+		h = i < tbl->size ? i : i - tbl->size;
+		nft_hash_for_each_entry(he, tbl->buckets[h]) {
+			if (nft_hash_data(&he->key, ntbl->size, set->klen) != i)
+				continue;
+			RCU_INIT_POINTER(ntbl->buckets[i], he);
+			break;
+		}
+	}
+
+	/* Publish new table */
+	rcu_assign_pointer(priv->tbl, ntbl);
+
+	/* Unzip interleaved hash chains */
+	do {
+		/* Wait for readers to use new table/unzipped chains */
+		synchronize_rcu();
+
+		complete = true;
+		for (i = 0; i < tbl->size; i++) {
+			nft_hash_chain_unzip(set, ntbl, tbl, i);
+			if (tbl->buckets[i] != NULL)
+				complete = false;
+		}
+	} while (!complete);
+
+	nft_hash_tbl_free(tbl);
+	return 0;
+}
+
+static int nft_hash_tbl_shrink(const struct nft_set *set, struct nft_hash *priv)
+{
+	struct nft_hash_table *tbl = nft_dereference(priv->tbl), *ntbl;
+	struct nft_hash_elem __rcu **pprev;
+	unsigned int i;
+
+	ntbl = nft_hash_tbl_alloc(tbl->size / 2);
+	if (ntbl == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < ntbl->size; i++) {
+		ntbl->buckets[i] = tbl->buckets[i];
+
+		for (pprev = &ntbl->buckets[i]; *pprev != NULL;
+		     pprev = &nft_dereference(*pprev)->next)
+			;
+		RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
+	}
+
+	/* Publish new table */
+	rcu_assign_pointer(priv->tbl, ntbl);
+	synchronize_rcu();
+
+	nft_hash_tbl_free(tbl);
+	return 0;
+}
+
+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_table *tbl = nft_dereference(priv->tbl);
+	struct nft_hash_elem *he;
+	unsigned int size, h;
+
+	if (elem->flags != 0)
+		return -EINVAL;
+
+	size = sizeof(*he);
+	if (set->flags & NFT_SET_MAP)
+		size += sizeof(he->data[0]);
+
+	he = kzalloc(size, GFP_KERNEL);
+	if (he == NULL)
+		return -ENOMEM;
+
+	nft_data_copy(&he->key, &elem->key);
+	if (set->flags & NFT_SET_MAP)
+		nft_data_copy(he->data, &elem->data);
+
+	h = nft_hash_data(&he->key, tbl->size, set->klen);
+	RCU_INIT_POINTER(he->next, tbl->buckets[h]);
+	rcu_assign_pointer(tbl->buckets[h], he);
+
+	/* Expand table when exceeding 75% load */
+	if (set->nelems + 1 > tbl->size / 4 * 3)
+		nft_hash_tbl_expand(set, priv);
+
+	return 0;
+}
+
+static void nft_hash_elem_destroy(const struct nft_set *set,
+				  struct nft_hash_elem *he)
+{
+	nft_data_uninit(&he->key, NFT_DATA_VALUE);
+	if (set->flags & NFT_SET_MAP)
+		nft_data_uninit(he->data, set->dtype);
+	kfree(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_table *tbl = nft_dereference(priv->tbl);
+	struct nft_hash_elem *he, __rcu **pprev;
+
+	pprev = elem->cookie;
+	he = nft_dereference((*pprev));
+
+	RCU_INIT_POINTER(*pprev, he->next);
+	synchronize_rcu();
+	kfree(he);
+
+	/* Shrink table beneath 30% load */
+	if (set->nelems - 1 < tbl->size * 3 / 10 &&
+	    tbl->size > NFT_HASH_MIN_SIZE)
+		nft_hash_tbl_shrink(set, priv);
+}
+
+static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
+{
+	const struct nft_hash *priv = nft_set_priv(set);
+	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
+	struct nft_hash_elem __rcu * const *pprev;
+	struct nft_hash_elem *he;
+	unsigned int h;
+
+	h = nft_hash_data(&elem->key, tbl->size, set->klen);
+	pprev = &tbl->buckets[h];
+	nft_hash_for_each_entry(he, tbl->buckets[h]) {
+		if (nft_data_cmp(&he->key, &elem->key, set->klen)) {
+			pprev = &he->next;
+			continue;
+		}
+
+		elem->cookie = (void *)pprev;
+		elem->flags = 0;
+		if (set->flags & NFT_SET_MAP)
+			nft_data_copy(&elem->data, he->data);
+		return 0;
+	}
+	return -ENOENT;
+}
+
+static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
+			  struct nft_set_iter *iter)
+{
+	const struct nft_hash *priv = nft_set_priv(set);
+	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
+	const struct nft_hash_elem *he;
+	struct nft_set_elem elem;
+	unsigned int i;
+
+	for (i = 0; i < tbl->size; i++) {
+		nft_hash_for_each_entry(he, tbl->buckets[i]) {
+			if (iter->count < iter->skip)
+				goto cont;
+
+			memcpy(&elem.key, &he->key, sizeof(elem.key));
+			if (set->flags & NFT_SET_MAP)
+				memcpy(&elem.data, he->data, sizeof(elem.data));
+			elem.flags = 0;
+
+			iter->err = iter->fn(ctx, set, iter, &elem);
+			if (iter->err < 0)
+				return;
+cont:
+			iter->count++;
+		}
+	}
+}
+
+static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
+{
+	return sizeof(struct nft_hash);
+}
+
+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 nft_hash_table *tbl;
+	unsigned int size;
+
+	if (unlikely(!nft_hash_rnd_initted)) {
+		get_random_bytes(&nft_hash_rnd, 4);
+		nft_hash_rnd_initted = true;
+	}
+
+	size = NFT_HASH_MIN_SIZE;
+	if (desc->size)
+		size = nft_hash_tbl_size(desc->size);
+
+	tbl = nft_hash_tbl_alloc(size);
+	if (tbl == NULL)
+		return -ENOMEM;
+	RCU_INIT_POINTER(priv->tbl, tbl);
+	return 0;
+}
+
+static void nft_hash_destroy(const struct nft_set *set)
+{
+	const struct nft_hash *priv = nft_set_priv(set);
+	const struct nft_hash_table *tbl = nft_dereference(priv->tbl);
+	struct nft_hash_elem *he, *next;
+	unsigned int i;
+
+	for (i = 0; i < tbl->size; i++) {
+		for (he = nft_dereference(tbl->buckets[i]); he != NULL;
+		     he = next) {
+			next = nft_dereference(he->next);
+			nft_hash_elem_destroy(set, he);
+		}
+	}
+	kfree(tbl);
+}
+
+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 (features & NFT_SET_MAP)
+		esize += FIELD_SIZEOF(struct nft_hash_elem, data[0]);
+
+	if (desc->size) {
+		est->size = sizeof(struct nft_hash) +
+			    nft_hash_tbl_size(desc->size) *
+			    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,
+	.estimate	= nft_hash_estimate,
+	.init		= nft_hash_init,
+	.destroy	= nft_hash_destroy,
+	.get		= nft_hash_get,
+	.insert		= nft_hash_insert,
+	.remove		= nft_hash_remove,
+	.lookup		= nft_hash_lookup,
+	.walk		= nft_hash_walk,
+	.features	= NFT_SET_MAP,
+	.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();