Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 316 insertions, 0 deletions

diff --git a/net/netfilter/nft_set_bitmap.c b/net/netfilter/nft_set_bitmap.c
new file mode 100644
index 000000000..1e5e7a181
--- /dev/null
+++ b/net/netfilter/nft_set_bitmap.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017 Pablo Neira Ayuso <pablo@netfilter.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+
+struct nft_bitmap_elem {
+	struct list_head	head;
+	struct nft_set_ext	ext;
+};
+
+/* This bitmap uses two bits to represent one element. These two bits determine
+ * the element state in the current and the future generation.
+ *
+ * An element can be in three states. The generation cursor is represented using
+ * the ^ character, note that this cursor shifts on every successful transaction.
+ * If no transaction is going on, we observe all elements are in the following
+ * state:
+ *
+ * 11 = this element is active in the current generation. In case of no updates,
+ * ^    it stays active in the next generation.
+ * 00 = this element is inactive in the current generation. In case of no
+ * ^    updates, it stays inactive in the next generation.
+ *
+ * On transaction handling, we observe these two temporary states:
+ *
+ * 01 = this element is inactive in the current generation and it becomes active
+ * ^    in the next one. This happens when the element is inserted but commit
+ *      path has not yet been executed yet, so activation is still pending. On
+ *      transaction abortion, the element is removed.
+ * 10 = this element is active in the current generation and it becomes inactive
+ * ^    in the next one. This happens when the element is deactivated but commit
+ *      path has not yet been executed yet, so removal is still pending. On
+ *      transaction abortion, the next generation bit is reset to go back to
+ *      restore its previous state.
+ */
+struct nft_bitmap {
+	struct	list_head	list;
+	u16			bitmap_size;
+	u8			bitmap[];
+};
+
+static inline void nft_bitmap_location(const struct nft_set *set,
+				       const void *key,
+				       u32 *idx, u32 *off)
+{
+	u32 k;
+
+	if (set->klen == 2)
+		k = *(u16 *)key;
+	else
+		k = *(u8 *)key;
+	k <<= 1;
+
+	*idx = k / BITS_PER_BYTE;
+	*off = k % BITS_PER_BYTE;
+}
+
+/* Fetch the two bits that represent the element and check if it is active based
+ * on the generation mask.
+ */
+static inline bool
+nft_bitmap_active(const u8 *bitmap, u32 idx, u32 off, u8 genmask)
+{
+	return (bitmap[idx] & (0x3 << off)) & (genmask << off);
+}
+
+INDIRECT_CALLABLE_SCOPE
+bool nft_bitmap_lookup(const struct net *net, const struct nft_set *set,
+		       const u32 *key, const struct nft_set_ext **ext)
+{
+	const struct nft_bitmap *priv = nft_set_priv(set);
+	u8 genmask = nft_genmask_cur(net);
+	u32 idx, off;
+
+	nft_bitmap_location(set, key, &idx, &off);
+
+	return nft_bitmap_active(priv->bitmap, idx, off, genmask);
+}
+
+static struct nft_bitmap_elem *
+nft_bitmap_elem_find(const struct nft_set *set, struct nft_bitmap_elem *this,
+		     u8 genmask)
+{
+	const struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *be;
+
+	list_for_each_entry_rcu(be, &priv->list, head) {
+		if (memcmp(nft_set_ext_key(&be->ext),
+			   nft_set_ext_key(&this->ext), set->klen) ||
+		    !nft_set_elem_active(&be->ext, genmask))
+			continue;
+
+		return be;
+	}
+	return NULL;
+}
+
+static void *nft_bitmap_get(const struct net *net, const struct nft_set *set,
+			    const struct nft_set_elem *elem, unsigned int flags)
+{
+	const struct nft_bitmap *priv = nft_set_priv(set);
+	u8 genmask = nft_genmask_cur(net);
+	struct nft_bitmap_elem *be;
+
+	list_for_each_entry_rcu(be, &priv->list, head) {
+		if (memcmp(nft_set_ext_key(&be->ext), elem->key.val.data, set->klen) ||
+		    !nft_set_elem_active(&be->ext, genmask))
+			continue;
+
+		return be;
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+static int nft_bitmap_insert(const struct net *net, const struct nft_set *set,
+			     const struct nft_set_elem *elem,
+			     struct nft_set_ext **ext)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *new = elem->priv, *be;
+	u8 genmask = nft_genmask_next(net);
+	u32 idx, off;
+
+	be = nft_bitmap_elem_find(set, new, genmask);
+	if (be) {
+		*ext = &be->ext;
+		return -EEXIST;
+	}
+
+	nft_bitmap_location(set, nft_set_ext_key(&new->ext), &idx, &off);
+	/* Enter 01 state. */
+	priv->bitmap[idx] |= (genmask << off);
+	list_add_tail_rcu(&new->head, &priv->list);
+
+	return 0;
+}
+
+static void nft_bitmap_remove(const struct net *net,
+			      const struct nft_set *set,
+			      const struct nft_set_elem *elem)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *be = elem->priv;
+	u8 genmask = nft_genmask_next(net);
+	u32 idx, off;
+
+	nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
+	/* Enter 00 state. */
+	priv->bitmap[idx] &= ~(genmask << off);
+	list_del_rcu(&be->head);
+}
+
+static void nft_bitmap_activate(const struct net *net,
+				const struct nft_set *set,
+				const struct nft_set_elem *elem)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *be = elem->priv;
+	u8 genmask = nft_genmask_next(net);
+	u32 idx, off;
+
+	nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
+	/* Enter 11 state. */
+	priv->bitmap[idx] |= (genmask << off);
+	nft_set_elem_change_active(net, set, &be->ext);
+}
+
+static bool nft_bitmap_flush(const struct net *net,
+			     const struct nft_set *set, void *_be)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	u8 genmask = nft_genmask_next(net);
+	struct nft_bitmap_elem *be = _be;
+	u32 idx, off;
+
+	nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
+	/* Enter 10 state, similar to deactivation. */
+	priv->bitmap[idx] &= ~(genmask << off);
+	nft_set_elem_change_active(net, set, &be->ext);
+
+	return true;
+}
+
+static void *nft_bitmap_deactivate(const struct net *net,
+				   const struct nft_set *set,
+				   const struct nft_set_elem *elem)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *this = elem->priv, *be;
+	u8 genmask = nft_genmask_next(net);
+	u32 idx, off;
+
+	nft_bitmap_location(set, elem->key.val.data, &idx, &off);
+
+	be = nft_bitmap_elem_find(set, this, genmask);
+	if (!be)
+		return NULL;
+
+	/* Enter 10 state. */
+	priv->bitmap[idx] &= ~(genmask << off);
+	nft_set_elem_change_active(net, set, &be->ext);
+
+	return be;
+}
+
+static void nft_bitmap_walk(const struct nft_ctx *ctx,
+			    struct nft_set *set,
+			    struct nft_set_iter *iter)
+{
+	const struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *be;
+	struct nft_set_elem elem;
+
+	list_for_each_entry_rcu(be, &priv->list, head) {
+		if (iter->count < iter->skip)
+			goto cont;
+		if (!nft_set_elem_active(&be->ext, iter->genmask))
+			goto cont;
+
+		elem.priv = be;
+
+		iter->err = iter->fn(ctx, set, iter, &elem);
+
+		if (iter->err < 0)
+			return;
+cont:
+		iter->count++;
+	}
+}
+
+/* The bitmap size is pow(2, key length in bits) / bits per byte. This is
+ * multiplied by two since each element takes two bits. For 8 bit keys, the
+ * bitmap consumes 66 bytes. For 16 bit keys, 16388 bytes.
+ */
+static inline u32 nft_bitmap_size(u32 klen)
+{
+	return ((2 << ((klen * BITS_PER_BYTE) - 1)) / BITS_PER_BYTE) << 1;
+}
+
+static inline u64 nft_bitmap_total_size(u32 klen)
+{
+	return sizeof(struct nft_bitmap) + nft_bitmap_size(klen);
+}
+
+static u64 nft_bitmap_privsize(const struct nlattr * const nla[],
+			       const struct nft_set_desc *desc)
+{
+	u32 klen = ntohl(nla_get_be32(nla[NFTA_SET_KEY_LEN]));
+
+	return nft_bitmap_total_size(klen);
+}
+
+static int nft_bitmap_init(const struct nft_set *set,
+			   const struct nft_set_desc *desc,
+			   const struct nlattr * const nla[])
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+
+	INIT_LIST_HEAD(&priv->list);
+	priv->bitmap_size = nft_bitmap_size(set->klen);
+
+	return 0;
+}
+
+static void nft_bitmap_destroy(const struct nft_ctx *ctx,
+			       const struct nft_set *set)
+{
+	struct nft_bitmap *priv = nft_set_priv(set);
+	struct nft_bitmap_elem *be, *n;
+
+	list_for_each_entry_safe(be, n, &priv->list, head)
+		nf_tables_set_elem_destroy(ctx, set, be);
+}
+
+static bool nft_bitmap_estimate(const struct nft_set_desc *desc, u32 features,
+				struct nft_set_estimate *est)
+{
+	/* Make sure bitmaps we don't get bitmaps larger than 16 Kbytes. */
+	if (desc->klen > 2)
+		return false;
+	else if (desc->expr)
+		return false;
+
+	est->size   = nft_bitmap_total_size(desc->klen);
+	est->lookup = NFT_SET_CLASS_O_1;
+	est->space  = NFT_SET_CLASS_O_1;
+
+	return true;
+}
+
+const struct nft_set_type nft_set_bitmap_type = {
+	.ops		= {
+		.privsize	= nft_bitmap_privsize,
+		.elemsize	= offsetof(struct nft_bitmap_elem, ext),
+		.estimate	= nft_bitmap_estimate,
+		.init		= nft_bitmap_init,
+		.destroy	= nft_bitmap_destroy,
+		.insert		= nft_bitmap_insert,
+		.remove		= nft_bitmap_remove,
+		.deactivate	= nft_bitmap_deactivate,
+		.flush		= nft_bitmap_flush,
+		.activate	= nft_bitmap_activate,
+		.lookup		= nft_bitmap_lookup,
+		.walk		= nft_bitmap_walk,
+		.get		= nft_bitmap_get,
+	},
+};