diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index dfbe9deeb8c4..ea479ed43373 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -509,6 +509,12 @@ config NFT_SET_HASH This option adds the "hash" set type that is used to build one-way mappings between matchings and actions. +config NFT_SET_BITMAP + tristate "Netfilter nf_tables bitmap set module" + help + This option adds the "bitmap" set type that is used to build sets + whose keys are smaller or equal to 16 bits. + config NFT_COUNTER tristate "Netfilter nf_tables counter module" help diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 6b3034f12661..c9b78e7b342f 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_NFT_REJECT) += nft_reject.o obj-$(CONFIG_NFT_REJECT_INET) += nft_reject_inet.o obj-$(CONFIG_NFT_SET_RBTREE) += nft_set_rbtree.o obj-$(CONFIG_NFT_SET_HASH) += nft_set_hash.o +obj-$(CONFIG_NFT_SET_BITMAP) += nft_set_bitmap.o obj-$(CONFIG_NFT_COUNTER) += nft_counter.o obj-$(CONFIG_NFT_LOG) += nft_log.o obj-$(CONFIG_NFT_MASQ) += nft_masq.o diff --git a/net/netfilter/nft_set_bitmap.c b/net/netfilter/nft_set_bitmap.c new file mode 100644 index 000000000000..97f9649bcc7e --- /dev/null +++ b/net/netfilter/nft_set_bitmap.c @@ -0,0 +1,314 @@ +/* + * Copyright (c) 2017 Pablo Neira Ayuso + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +/* 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 "); +MODULE_ALIAS_NFT_SET();