1 files changed, 348 insertions, 0 deletions
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
new file mode 100644
index 0000000..67cc502
--- /dev/null
+++ b/net/netfilter/nft_hash.c
@@ -0,0 +1,348 @@
+/*
+ * Copyright (c) 2008 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/jhash.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_hash {
+	struct hlist_head	*hash;
+	unsigned int		hsize;
+	enum nft_registers	sreg:8;
+	enum nft_registers	dreg:8;
+	u8			klen;
+	u8			dlen;
+	u16			flags;
+};
+
+struct nft_hash_elem {
+	struct hlist_node	hnode;
+	struct nft_data		key;
+	struct nft_data		data[];
+};
+
+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;
+
+	// FIXME: can we reasonably guarantee the upper bits are fixed?
+	h = jhash2(data->data, len >> 2, nft_hash_rnd);
+	return ((u64)h * hsize) >> 32;
+}
+
+static void nft_hash_eval(const struct nft_expr *expr,
+			  struct nft_data data[NFT_REG_MAX + 1],
+			  const struct nft_pktinfo *pkt)
+{
+	const struct nft_hash *priv = nft_expr_priv(expr);
+	const struct nft_hash_elem *elem;
+	const struct nft_data *key = &data[priv->sreg];
+	unsigned int h;
+
+	h = nft_hash_data(key, priv->hsize, priv->klen);
+	hlist_for_each_entry(elem, &priv->hash[h], hnode) {
+		if (nft_data_cmp(&elem->key, key, priv->klen))
+			continue;
+		if (priv->flags & NFT_HASH_MAP)
+			nft_data_copy(&data[priv->dreg], elem->data);
+		return;
+	}
+	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
+}
+
+static void nft_hash_elem_destroy(const struct nft_expr *expr,
+				  struct nft_hash_elem *elem)
+{
+	const struct nft_hash *priv = nft_expr_priv(expr);
+
+	nft_data_uninit(&elem->key, NFT_DATA_VALUE);
+	if (priv->flags & NFT_HASH_MAP)
+		nft_data_uninit(elem->data, nft_dreg_to_type(priv->dreg));
+	kfree(elem);
+}
+
+static const struct nla_policy nft_he_policy[NFTA_HE_MAX + 1] = {
+	[NFTA_HE_KEY]		= { .type = NLA_NESTED },
+	[NFTA_HE_DATA]		= { .type = NLA_NESTED },
+};
+
+static int nft_hash_elem_init(const struct nft_ctx *ctx,
+			      const struct nft_expr *expr,
+			      const struct nlattr *nla,
+			      struct nft_hash_elem **new)
+{
+	struct nft_hash *priv = nft_expr_priv(expr);
+	struct nlattr *tb[NFTA_HE_MAX + 1];
+	struct nft_hash_elem *elem;
+	struct nft_data_desc d1, d2;
+	unsigned int size;
+	int err;
+
+	err = nla_parse_nested(tb, NFTA_HE_MAX, nla, nft_he_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[NFTA_HE_KEY] == NULL)
+		return -EINVAL;
+	size = sizeof(*elem);
+
+	if (priv->flags & NFT_HASH_MAP) {
+		if (tb[NFTA_HE_DATA] == NULL)
+			return -EINVAL;
+		size += sizeof(elem->data[0]);
+	} else {
+		if (tb[NFTA_HE_DATA] != NULL)
+			return -EINVAL;
+	}
+
+	elem = kzalloc(size, GFP_KERNEL);
+	if (elem == NULL)
+		return -ENOMEM;
+
+	err = nft_data_init(ctx, &elem->key, &d1, tb[NFTA_HE_KEY]);
+	if (err < 0)
+		goto err1;
+	err = -EINVAL;
+	if (d1.type != NFT_DATA_VALUE || d1.len != priv->klen)
+		goto err2;
+
+	if (tb[NFTA_HE_DATA] != NULL) {
+		err = nft_data_init(ctx, elem->data, &d2, tb[NFTA_HE_DATA]);
+		if (err < 0)
+			goto err2;
+		err = nft_validate_data_load(ctx, priv->dreg, elem->data, d2.type);
+		if (err < 0)
+			goto err3;
+	}
+
+	*new = elem;
+	return 0;
+
+err3:
+	nft_data_uninit(elem->data, d2.type);
+err2:
+	nft_data_uninit(&elem->key, d1.type);
+err1:
+	kfree(elem);
+	return err;
+}
+
+static int nft_hash_elem_dump(struct sk_buff *skb, const struct nft_expr *expr,
+			      const struct nft_hash_elem *elem)
+
+{
+	const struct nft_hash *priv = nft_expr_priv(expr);
+	struct nlattr *nest;
+
+	nest = nla_nest_start(skb, NFTA_LIST_ELEM);
+	if (nest == NULL)
+		goto nla_put_failure;
+
+	if (nft_data_dump(skb, NFTA_HE_KEY, &elem->key,
+			  NFT_DATA_VALUE, priv->klen) < 0)
+		goto nla_put_failure;
+
+	if (priv->flags & NFT_HASH_MAP) {
+		if (nft_data_dump(skb, NFTA_HE_DATA, elem->data,
+				  NFT_DATA_VALUE, priv->dlen) < 0)
+			goto nla_put_failure;
+	}
+
+	nla_nest_end(skb, nest);
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static void nft_hash_destroy(const struct nft_ctx *ctx,
+			     const struct nft_expr *expr)
+{
+	const struct nft_hash *priv = nft_expr_priv(expr);
+	const struct hlist_node *next;
+	struct nft_hash_elem *elem;
+	unsigned int i;
+
+	for (i = 0; i < priv->hsize; i++) {
+		hlist_for_each_entry_safe(elem, next, &priv->hash[i], hnode) {
+			hlist_del(&elem->hnode);
+			nft_hash_elem_destroy(expr, elem);
+		}
+	}
+	kfree(priv->hash);
+}
+
+static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
+	[NFTA_HASH_FLAGS]	= { .type = NLA_U32 },
+	[NFTA_HASH_SREG]	= { .type = NLA_U32 },
+	[NFTA_HASH_DREG]	= { .type = NLA_U32 },
+	[NFTA_HASH_KLEN]	= { .type = NLA_U32 },
+	[NFTA_HASH_ELEMENTS]	= { .type = NLA_NESTED },
+};
+
+static int nft_hash_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+			 const struct nlattr * const tb[])
+{
+	struct nft_hash *priv = nft_expr_priv(expr);
+	struct nft_hash_elem *elem, *uninitialized_var(new);
+	const struct nlattr *nla;
+	unsigned int cnt, i;
+	unsigned int h;
+	int err, rem;
+
+	if (unlikely(!nft_hash_rnd_initted)) {
+		get_random_bytes(&nft_hash_rnd, 4);
+		nft_hash_rnd_initted = true;
+	}
+
+	if (tb[NFTA_HASH_SREG] == NULL ||
+	    tb[NFTA_HASH_KLEN] == NULL ||
+	    tb[NFTA_HASH_ELEMENTS] == NULL)
+		return -EINVAL;
+
+	if (tb[NFTA_HASH_FLAGS] != NULL) {
+		priv->flags = ntohl(nla_get_be32(tb[NFTA_HASH_FLAGS]));
+		if (priv->flags & ~NFT_HASH_MAP)
+			return -EINVAL;
+	}
+
+	priv->sreg = ntohl(nla_get_be32(tb[NFTA_HASH_SREG]));
+	err = nft_validate_input_register(priv->sreg);
+	if (err < 0)
+		return err;
+
+	if (tb[NFTA_HASH_DREG] != NULL) {
+		if (!(priv->flags & NFT_HASH_MAP))
+			return -EINVAL;
+		priv->dreg = ntohl(nla_get_be32(tb[NFTA_HASH_DREG]));
+		err = nft_validate_output_register(priv->dreg);
+		if (err < 0)
+			return err;
+	}
+
+	priv->klen = ntohl(nla_get_be32(tb[NFTA_HASH_KLEN]));
+	if (priv->klen == 0)
+		return -EINVAL;
+
+	cnt = 0;
+	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
+		if (nla_type(nla) != NFTA_LIST_ELEM)
+			return -EINVAL;
+		cnt++;
+	}
+
+	/* Aim for a load factor of 0.75 */
+	cnt = cnt * 4 / 3;
+
+	priv->hash = kcalloc(cnt, sizeof(struct hlist_head), GFP_KERNEL);
+	if (priv->hash == NULL)
+		return -ENOMEM;
+	priv->hsize = cnt;
+
+	for (i = 0; i < cnt; i++)
+		INIT_HLIST_HEAD(&priv->hash[i]);
+
+	err = -ENOMEM;
+	nla_for_each_nested(nla, tb[NFTA_HASH_ELEMENTS], rem) {
+		err = nft_hash_elem_init(ctx, expr, nla, &new);
+		if (err < 0)
+			goto err1;
+
+		h = nft_hash_data(&new->key, priv->hsize, priv->klen);
+		hlist_for_each_entry(elem, &priv->hash[h], hnode) {
+			if (nft_data_cmp(&elem->key, &new->key, priv->klen))
+				continue;
+			nft_hash_elem_destroy(expr, new);
+			err = -EEXIST;
+			goto err1;
+		}
+		hlist_add_head(&new->hnode, &priv->hash[h]);
+	}
+	return 0;
+
+err1:
+	nft_hash_destroy(ctx, expr);
+	return err;
+}
+
+static int nft_hash_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_hash *priv = nft_expr_priv(expr);
+	const struct nft_hash_elem *elem;
+	struct nlattr *list;
+	unsigned int i;
+
+	if (priv->flags)
+		if (nla_put_be32(skb, NFTA_HASH_FLAGS, htonl(priv->flags)))
+			goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_HASH_SREG, htonl(priv->sreg)))
+		goto nla_put_failure;
+	if (priv->flags & NFT_HASH_MAP)
+		if (nla_put_be32(skb, NFTA_HASH_DREG, htonl(priv->dreg)))
+			goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_HASH_KLEN, htonl(priv->klen)))
+		goto nla_put_failure;
+
+	list = nla_nest_start(skb, NFTA_HASH_ELEMENTS);
+	if (list == NULL)
+		goto nla_put_failure;
+
+	for (i = 0; i < priv->hsize; i++) {
+		hlist_for_each_entry(elem, &priv->hash[i], hnode) {
+			if (nft_hash_elem_dump(skb, expr, elem) < 0)
+				goto nla_put_failure;
+		}
+	}
+
+	nla_nest_end(skb, list);
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static struct nft_expr_ops nft_hash_ops __read_mostly = {
+	.name		= "hash",
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_hash)),
+	.owner		= THIS_MODULE,
+	.eval		= nft_hash_eval,
+	.init		= nft_hash_init,
+	.destroy	= nft_hash_destroy,
+	.dump		= nft_hash_dump,
+	.policy		= nft_hash_policy,
+	.maxattr	= NFTA_HASH_MAX,
+};
+
+static int __init nft_hash_module_init(void)
+{
+	return nft_register_expr(&nft_hash_ops);
+}
+
+static void __exit nft_hash_module_exit(void)
+{
+	nft_unregister_expr(&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_EXPR("hash");