|
@@ -0,0 +1,314 @@
|
|
|
+/*
|
|
|
+ * Copyright (c) 2017 Pablo Neira Ayuso <pablo@netfilter.org>
|
|
|
+ *
|
|
|
+ * 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.
|
|
|
+ */
|
|
|
+
|
|
|
+#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.h>
|
|
|
+
|
|
|
+/* 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 succesful 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
|
|
|
+ * transation abortion, the next generation bit is reset to go back to
|
|
|
+ * restore its previous state.
|
|
|
+ */
|
|
|
+struct nft_bitmap {
|
|
|
+ u16 bitmap_size;
|
|
|
+ u8 bitmap[];
|
|
|
+};
|
|
|
+
|
|
|
+static inline void nft_bitmap_location(u32 key, u32 *idx, u32 *off)
|
|
|
+{
|
|
|
+ u32 k = (key << 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);
|
|
|
+}
|
|
|
+
|
|
|
+static 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(*key, &idx, &off);
|
|
|
+
|
|
|
+ return nft_bitmap_active(priv->bitmap, idx, off, genmask);
|
|
|
+}
|
|
|
+
|
|
|
+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_set_ext *ext = elem->priv;
|
|
|
+ u8 genmask = nft_genmask_next(net);
|
|
|
+ u32 idx, off;
|
|
|
+
|
|
|
+ nft_bitmap_location(nft_set_ext_key(ext)->data[0], &idx, &off);
|
|
|
+ if (nft_bitmap_active(priv->bitmap, idx, off, genmask))
|
|
|
+ return -EEXIST;
|
|
|
+
|
|
|
+ /* Enter 01 state. */
|
|
|
+ priv->bitmap[idx] |= (genmask << off);
|
|
|
+
|
|
|
+ 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_set_ext *ext = elem->priv;
|
|
|
+ u8 genmask = nft_genmask_next(net);
|
|
|
+ u32 idx, off;
|
|
|
+
|
|
|
+ nft_bitmap_location(nft_set_ext_key(ext)->data[0], &idx, &off);
|
|
|
+ /* Enter 00 state. */
|
|
|
+ priv->bitmap[idx] &= ~(genmask << off);
|
|
|
+}
|
|
|
+
|
|
|
+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_set_ext *ext = elem->priv;
|
|
|
+ u8 genmask = nft_genmask_next(net);
|
|
|
+ u32 idx, off;
|
|
|
+
|
|
|
+ nft_bitmap_location(nft_set_ext_key(ext)->data[0], &idx, &off);
|
|
|
+ /* Enter 11 state. */
|
|
|
+ priv->bitmap[idx] |= (genmask << off);
|
|
|
+}
|
|
|
+
|
|
|
+static bool nft_bitmap_flush(const struct net *net,
|
|
|
+ const struct nft_set *set, void *ext)
|
|
|
+{
|
|
|
+ struct nft_bitmap *priv = nft_set_priv(set);
|
|
|
+ u8 genmask = nft_genmask_next(net);
|
|
|
+ u32 idx, off;
|
|
|
+
|
|
|
+ nft_bitmap_location(nft_set_ext_key(ext)->data[0], &idx, &off);
|
|
|
+ /* Enter 10 state, similar to deactivation. */
|
|
|
+ priv->bitmap[idx] &= ~(genmask << off);
|
|
|
+
|
|
|
+ return true;
|
|
|
+}
|
|
|
+
|
|
|
+static struct nft_set_ext *nft_bitmap_ext_alloc(const struct nft_set *set,
|
|
|
+ const struct nft_set_elem *elem)
|
|
|
+{
|
|
|
+ struct nft_set_ext_tmpl tmpl;
|
|
|
+ struct nft_set_ext *ext;
|
|
|
+
|
|
|
+ nft_set_ext_prepare(&tmpl);
|
|
|
+ nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, set->klen);
|
|
|
+
|
|
|
+ ext = kzalloc(tmpl.len, GFP_KERNEL);
|
|
|
+ if (!ext)
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ nft_set_ext_init(ext, &tmpl);
|
|
|
+ memcpy(nft_set_ext_key(ext), elem->key.val.data, set->klen);
|
|
|
+
|
|
|
+ return ext;
|
|
|
+}
|
|
|
+
|
|
|
+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);
|
|
|
+ u8 genmask = nft_genmask_next(net);
|
|
|
+ struct nft_set_ext *ext;
|
|
|
+ u32 idx, off, key = 0;
|
|
|
+
|
|
|
+ memcpy(&key, elem->key.val.data, set->klen);
|
|
|
+ nft_bitmap_location(key, &idx, &off);
|
|
|
+
|
|
|
+ if (!nft_bitmap_active(priv->bitmap, idx, off, genmask))
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ /* We have no real set extension since this is a bitmap, allocate this
|
|
|
+ * dummy object that is released from the commit/abort path.
|
|
|
+ */
|
|
|
+ ext = nft_bitmap_ext_alloc(set, elem);
|
|
|
+ if (!ext)
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ /* Enter 10 state. */
|
|
|
+ priv->bitmap[idx] &= ~(genmask << off);
|
|
|
+
|
|
|
+ return ext;
|
|
|
+}
|
|
|
+
|
|
|
+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_set_ext_tmpl tmpl;
|
|
|
+ struct nft_set_elem elem;
|
|
|
+ struct nft_set_ext *ext;
|
|
|
+ int idx, off;
|
|
|
+ u16 key;
|
|
|
+
|
|
|
+ nft_set_ext_prepare(&tmpl);
|
|
|
+ nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, set->klen);
|
|
|
+
|
|
|
+ for (idx = 0; idx < priv->bitmap_size; idx++) {
|
|
|
+ for (off = 0; off < BITS_PER_BYTE; off += 2) {
|
|
|
+ if (iter->count < iter->skip)
|
|
|
+ goto cont;
|
|
|
+
|
|
|
+ if (!nft_bitmap_active(priv->bitmap, idx, off,
|
|
|
+ iter->genmask))
|
|
|
+ goto cont;
|
|
|
+
|
|
|
+ ext = kzalloc(tmpl.len, GFP_KERNEL);
|
|
|
+ if (!ext) {
|
|
|
+ iter->err = -ENOMEM;
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ nft_set_ext_init(ext, &tmpl);
|
|
|
+ key = ((idx * BITS_PER_BYTE) + off) >> 1;
|
|
|
+ memcpy(nft_set_ext_key(ext), &key, set->klen);
|
|
|
+
|
|
|
+ elem.priv = ext;
|
|
|
+ iter->err = iter->fn(ctx, set, iter, &elem);
|
|
|
+
|
|
|
+ /* On set flush, this dummy extension object is released
|
|
|
+ * from the commit/abort path.
|
|
|
+ */
|
|
|
+ if (!iter->flush)
|
|
|
+ kfree(ext);
|
|
|
+
|
|
|
+ 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 u32 nft_bitmap_total_size(u32 klen)
|
|
|
+{
|
|
|
+ return sizeof(struct nft_bitmap) + nft_bitmap_size(klen);
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned int nft_bitmap_privsize(const struct nlattr * const nla[])
|
|
|
+{
|
|
|
+ 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);
|
|
|
+
|
|
|
+ priv->bitmap_size = nft_bitmap_total_size(set->klen);
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+static void nft_bitmap_destroy(const struct nft_set *set)
|
|
|
+{
|
|
|
+}
|
|
|
+
|
|
|
+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;
|
|
|
+
|
|
|
+ est->size = nft_bitmap_total_size(desc->klen);
|
|
|
+ est->lookup = NFT_SET_CLASS_O_1;
|
|
|
+ est->space = NFT_SET_CLASS_O_1;
|
|
|
+
|
|
|
+ return true;
|
|
|
+}
|
|
|
+
|
|
|
+static struct nft_set_ops nft_bitmap_ops __read_mostly = {
|
|
|
+ .privsize = nft_bitmap_privsize,
|
|
|
+ .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,
|
|
|
+ .owner = THIS_MODULE,
|
|
|
+};
|
|
|
+
|
|
|
+static int __init nft_bitmap_module_init(void)
|
|
|
+{
|
|
|
+ return nft_register_set(&nft_bitmap_ops);
|
|
|
+}
|
|
|
+
|
|
|
+static void __exit nft_bitmap_module_exit(void)
|
|
|
+{
|
|
|
+ nft_unregister_set(&nft_bitmap_ops);
|
|
|
+}
|
|
|
+
|
|
|
+module_init(nft_bitmap_module_init);
|
|
|
+module_exit(nft_bitmap_module_exit);
|
|
|
+
|
|
|
+MODULE_LICENSE("GPL");
|
|
|
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
|
|
|
+MODULE_ALIAS_NFT_SET();
|