From 8683f4b9950d308079be74f9a32d6c3eee9c3f1b Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Sat, 7 Mar 2020 17:52:35 +0100 Subject: nft_set_pipapo: Prepare for vectorised implementation: helpers Move most macros and helpers to a header file, so that they can be conveniently used by related implementations. No functional changes are intended here. Signed-off-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_set_pipapo.h | 277 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 277 insertions(+) create mode 100644 net/netfilter/nft_set_pipapo.h (limited to 'net/netfilter/nft_set_pipapo.h') diff --git a/net/netfilter/nft_set_pipapo.h b/net/netfilter/nft_set_pipapo.h new file mode 100644 index 000000000000..3cfc0a385ee2 --- /dev/null +++ b/net/netfilter/nft_set_pipapo.h @@ -0,0 +1,277 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#ifndef _NFT_SET_PIPAPO_H + +#include +#include /* For the maximum length of a field */ + +/* Count of concatenated fields depends on count of 32-bit nftables registers */ +#define NFT_PIPAPO_MAX_FIELDS NFT_REG32_COUNT + +/* Largest supported field size */ +#define NFT_PIPAPO_MAX_BYTES (sizeof(struct in6_addr)) +#define NFT_PIPAPO_MAX_BITS (NFT_PIPAPO_MAX_BYTES * BITS_PER_BYTE) + +/* Bits to be grouped together in table buckets depending on set size */ +#define NFT_PIPAPO_GROUP_BITS_INIT NFT_PIPAPO_GROUP_BITS_SMALL_SET +#define NFT_PIPAPO_GROUP_BITS_SMALL_SET 8 +#define NFT_PIPAPO_GROUP_BITS_LARGE_SET 4 +#define NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4 \ + BUILD_BUG_ON((NFT_PIPAPO_GROUP_BITS_SMALL_SET != 8) || \ + (NFT_PIPAPO_GROUP_BITS_LARGE_SET != 4)) +#define NFT_PIPAPO_GROUPS_PER_BYTE(f) (BITS_PER_BYTE / (f)->bb) + +/* If a lookup table gets bigger than NFT_PIPAPO_LT_SIZE_HIGH, switch to the + * small group width, and switch to the big group width if the table gets + * smaller than NFT_PIPAPO_LT_SIZE_LOW. + * + * Picking 2MiB as threshold (for a single table) avoids as much as possible + * crossing page boundaries on most architectures (x86-64 and MIPS huge pages, + * ARMv7 supersections, POWER "large" pages, SPARC Level 1 regions, etc.), which + * keeps performance nice in case kvmalloc() gives us non-contiguous areas. + */ +#define NFT_PIPAPO_LT_SIZE_THRESHOLD (1 << 21) +#define NFT_PIPAPO_LT_SIZE_HYSTERESIS (1 << 16) +#define NFT_PIPAPO_LT_SIZE_HIGH NFT_PIPAPO_LT_SIZE_THRESHOLD +#define NFT_PIPAPO_LT_SIZE_LOW NFT_PIPAPO_LT_SIZE_THRESHOLD - \ + NFT_PIPAPO_LT_SIZE_HYSTERESIS + +/* Fields are padded to 32 bits in input registers */ +#define NFT_PIPAPO_GROUPS_PADDED_SIZE(f) \ + (round_up((f)->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f), sizeof(u32))) +#define NFT_PIPAPO_GROUPS_PADDING(f) \ + (NFT_PIPAPO_GROUPS_PADDED_SIZE(f) - (f)->groups / \ + NFT_PIPAPO_GROUPS_PER_BYTE(f)) + +/* Number of buckets given by 2 ^ n, with n bucket bits */ +#define NFT_PIPAPO_BUCKETS(bb) (1 << (bb)) + +/* Each n-bit range maps to up to n * 2 rules */ +#define NFT_PIPAPO_MAP_NBITS (const_ilog2(NFT_PIPAPO_MAX_BITS * 2)) + +/* Use the rest of mapping table buckets for rule indices, but it makes no sense + * to exceed 32 bits + */ +#if BITS_PER_LONG == 64 +#define NFT_PIPAPO_MAP_TOBITS 32 +#else +#define NFT_PIPAPO_MAP_TOBITS (BITS_PER_LONG - NFT_PIPAPO_MAP_NBITS) +#endif + +/* ...which gives us the highest allowed index for a rule */ +#define NFT_PIPAPO_RULE0_MAX ((1UL << (NFT_PIPAPO_MAP_TOBITS - 1)) \ + - (1UL << NFT_PIPAPO_MAP_NBITS)) + +/* Definitions for vectorised implementations */ +#ifdef NFT_PIPAPO_ALIGN +#define NFT_PIPAPO_ALIGN_HEADROOM \ + (NFT_PIPAPO_ALIGN - ARCH_KMALLOC_MINALIGN) +#define NFT_PIPAPO_LT_ALIGN(lt) (PTR_ALIGN((lt), NFT_PIPAPO_ALIGN)) +#define NFT_PIPAPO_LT_ASSIGN(field, x) \ + do { \ + (field)->lt_aligned = NFT_PIPAPO_LT_ALIGN(x); \ + (field)->lt = (x); \ + } while (0) +#else +#define NFT_PIPAPO_ALIGN_HEADROOM 0 +#define NFT_PIPAPO_LT_ALIGN(lt) (lt) +#define NFT_PIPAPO_LT_ASSIGN(field, x) ((field)->lt = (x)) +#endif /* NFT_PIPAPO_ALIGN */ + +#define nft_pipapo_for_each_field(field, index, match) \ + for ((field) = (match)->f, (index) = 0; \ + (index) < (match)->field_count; \ + (index)++, (field)++) + +/** + * union nft_pipapo_map_bucket - Bucket of mapping table + * @to: First rule number (in next field) this rule maps to + * @n: Number of rules (in next field) this rule maps to + * @e: If there's no next field, pointer to element this rule maps to + */ +union nft_pipapo_map_bucket { + struct { +#if BITS_PER_LONG == 64 + static_assert(NFT_PIPAPO_MAP_TOBITS <= 32); + u32 to; + + static_assert(NFT_PIPAPO_MAP_NBITS <= 32); + u32 n; +#else + unsigned long to:NFT_PIPAPO_MAP_TOBITS; + unsigned long n:NFT_PIPAPO_MAP_NBITS; +#endif + }; + struct nft_pipapo_elem *e; +}; + +/** + * struct nft_pipapo_field - Lookup, mapping tables and related data for a field + * @groups: Amount of bit groups + * @rules: Number of inserted rules + * @bsize: Size of each bucket in lookup table, in longs + * @bb: Number of bits grouped together in lookup table buckets + * @lt: Lookup table: 'groups' rows of buckets + * @lt_aligned: Version of @lt aligned to NFT_PIPAPO_ALIGN bytes + * @mt: Mapping table: one bucket per rule + */ +struct nft_pipapo_field { + int groups; + unsigned long rules; + size_t bsize; + int bb; +#ifdef NFT_PIPAPO_ALIGN + unsigned long *lt_aligned; +#endif + unsigned long *lt; + union nft_pipapo_map_bucket *mt; +}; + +/** + * struct nft_pipapo_match - Data used for lookup and matching + * @field_count Amount of fields in set + * @scratch: Preallocated per-CPU maps for partial matching results + * @scratch_aligned: Version of @scratch aligned to NFT_PIPAPO_ALIGN bytes + * @bsize_max: Maximum lookup table bucket size of all fields, in longs + * @rcu Matching data is swapped on commits + * @f: Fields, with lookup and mapping tables + */ +struct nft_pipapo_match { + int field_count; +#ifdef NFT_PIPAPO_ALIGN + unsigned long * __percpu *scratch_aligned; +#endif + unsigned long * __percpu *scratch; + size_t bsize_max; + struct rcu_head rcu; + struct nft_pipapo_field f[]; +}; + +/** + * struct nft_pipapo - Representation of a set + * @match: Currently in-use matching data + * @clone: Copy where pending insertions and deletions are kept + * @width: Total bytes to be matched for one packet, including padding + * @dirty: Working copy has pending insertions or deletions + * @last_gc: Timestamp of last garbage collection run, jiffies + */ +struct nft_pipapo { + struct nft_pipapo_match __rcu *match; + struct nft_pipapo_match *clone; + int width; + bool dirty; + unsigned long last_gc; +}; + +struct nft_pipapo_elem; + +/** + * struct nft_pipapo_elem - API-facing representation of single set element + * @ext: nftables API extensions + */ +struct nft_pipapo_elem { + struct nft_set_ext ext; +}; + +int pipapo_refill(unsigned long *map, int len, int rules, unsigned long *dst, + union nft_pipapo_map_bucket *mt, bool match_only); + +/** + * pipapo_and_field_buckets_4bit() - Intersect 4-bit buckets + * @f: Field including lookup table + * @dst: Area to store result + * @data: Input data selecting table buckets + */ +static inline void pipapo_and_field_buckets_4bit(struct nft_pipapo_field *f, + unsigned long *dst, + const u8 *data) +{ + unsigned long *lt = NFT_PIPAPO_LT_ALIGN(f->lt); + int group; + + for (group = 0; group < f->groups; group += BITS_PER_BYTE / 4, data++) { + u8 v; + + v = *data >> 4; + __bitmap_and(dst, dst, lt + v * f->bsize, + f->bsize * BITS_PER_LONG); + lt += f->bsize * NFT_PIPAPO_BUCKETS(4); + + v = *data & 0x0f; + __bitmap_and(dst, dst, lt + v * f->bsize, + f->bsize * BITS_PER_LONG); + lt += f->bsize * NFT_PIPAPO_BUCKETS(4); + } +} + +/** + * pipapo_and_field_buckets_8bit() - Intersect 8-bit buckets + * @f: Field including lookup table + * @dst: Area to store result + * @data: Input data selecting table buckets + */ +static inline void pipapo_and_field_buckets_8bit(struct nft_pipapo_field *f, + unsigned long *dst, + const u8 *data) +{ + unsigned long *lt = NFT_PIPAPO_LT_ALIGN(f->lt); + int group; + + for (group = 0; group < f->groups; group++, data++) { + __bitmap_and(dst, dst, lt + *data * f->bsize, + f->bsize * BITS_PER_LONG); + lt += f->bsize * NFT_PIPAPO_BUCKETS(8); + } +} + +/** + * pipapo_estimate_size() - Estimate worst-case for set size + * @desc: Set description, element count and field description used here + * + * The size for this set type can vary dramatically, as it depends on the number + * of rules (composing netmasks) the entries expand to. We compute the worst + * case here. + * + * In general, for a non-ranged entry or a single composing netmask, we need + * one bit in each of the sixteen NFT_PIPAPO_BUCKETS, for each 4-bit group (that + * is, each input bit needs four bits of matching data), plus a bucket in the + * mapping table for each field. + * + * Return: worst-case set size in bytes, 0 on any overflow + */ +static u64 pipapo_estimate_size(const struct nft_set_desc *desc) +{ + unsigned long entry_size; + u64 size; + int i; + + for (i = 0, entry_size = 0; i < desc->field_count; i++) { + unsigned long rules; + + if (desc->field_len[i] > NFT_PIPAPO_MAX_BYTES) + return 0; + + /* Worst-case ranges for each concatenated field: each n-bit + * field can expand to up to n * 2 rules in each bucket, and + * each rule also needs a mapping bucket. + */ + rules = ilog2(desc->field_len[i] * BITS_PER_BYTE) * 2; + entry_size += rules * + NFT_PIPAPO_BUCKETS(NFT_PIPAPO_GROUP_BITS_INIT) / + BITS_PER_BYTE; + entry_size += rules * sizeof(union nft_pipapo_map_bucket); + } + + /* Rules in lookup and mapping tables are needed for each entry */ + size = desc->size * entry_size; + if (size && div_u64(size, desc->size) != entry_size) + return 0; + + size += sizeof(struct nft_pipapo) + sizeof(struct nft_pipapo_match) * 2; + + size += sizeof(struct nft_pipapo_field) * desc->field_count; + + return size; +} + +#endif /* _NFT_SET_PIPAPO_H */ -- cgit