1 // SPDX-License-Identifier: GPL-2.0-only
2
3 #ifndef _NFT_SET_PIPAPO_H
4
5 #include <linux/log2.h>
6 #include <net/ipv6.h> /* For the maximum length of a field */
7
8 /* Count of concatenated fields depends on count of 32-bit nftables registers */
9 #define NFT_PIPAPO_MAX_FIELDS NFT_REG32_COUNT
10
11 /* Restrict usage to multiple fields, make sure rbtree is used otherwise */
12 #define NFT_PIPAPO_MIN_FIELDS 2
13
14 /* Largest supported field size */
15 #define NFT_PIPAPO_MAX_BYTES (sizeof(struct in6_addr))
16 #define NFT_PIPAPO_MAX_BITS (NFT_PIPAPO_MAX_BYTES * BITS_PER_BYTE)
17
18 /* Bits to be grouped together in table buckets depending on set size */
19 #define NFT_PIPAPO_GROUP_BITS_INIT NFT_PIPAPO_GROUP_BITS_SMALL_SET
20 #define NFT_PIPAPO_GROUP_BITS_SMALL_SET 8
21 #define NFT_PIPAPO_GROUP_BITS_LARGE_SET 4
22 #define NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4 \
23 BUILD_BUG_ON((NFT_PIPAPO_GROUP_BITS_SMALL_SET != 8) || \
24 (NFT_PIPAPO_GROUP_BITS_LARGE_SET != 4))
25 #define NFT_PIPAPO_GROUPS_PER_BYTE(f) (BITS_PER_BYTE / (f)->bb)
26
27 /* If a lookup table gets bigger than NFT_PIPAPO_LT_SIZE_HIGH, switch to the
28 * small group width, and switch to the big group width if the table gets
29 * smaller than NFT_PIPAPO_LT_SIZE_LOW.
30 *
31 * Picking 2MiB as threshold (for a single table) avoids as much as possible
32 * crossing page boundaries on most architectures (x86-64 and MIPS huge pages,
33 * ARMv7 supersections, POWER "large" pages, SPARC Level 1 regions, etc.), which
34 * keeps performance nice in case kvmalloc() gives us non-contiguous areas.
35 */
36 #define NFT_PIPAPO_LT_SIZE_THRESHOLD (1 << 21)
37 #define NFT_PIPAPO_LT_SIZE_HYSTERESIS (1 << 16)
38 #define NFT_PIPAPO_LT_SIZE_HIGH NFT_PIPAPO_LT_SIZE_THRESHOLD
39 #define NFT_PIPAPO_LT_SIZE_LOW NFT_PIPAPO_LT_SIZE_THRESHOLD - \
40 NFT_PIPAPO_LT_SIZE_HYSTERESIS
41
42 /* Fields are padded to 32 bits in input registers */
43 #define NFT_PIPAPO_GROUPS_PADDED_SIZE(f) \
44 (round_up((f)->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f), sizeof(u32)))
45 #define NFT_PIPAPO_GROUPS_PADDING(f) \
46 (NFT_PIPAPO_GROUPS_PADDED_SIZE(f) - (f)->groups / \
47 NFT_PIPAPO_GROUPS_PER_BYTE(f))
48
49 /* Number of buckets given by 2 ^ n, with n bucket bits */
50 #define NFT_PIPAPO_BUCKETS(bb) (1 << (bb))
51
52 /* Each n-bit range maps to up to n * 2 rules */
53 #define NFT_PIPAPO_MAP_NBITS (const_ilog2(NFT_PIPAPO_MAX_BITS * 2))
54
55 /* Use the rest of mapping table buckets for rule indices, but it makes no sense
56 * to exceed 32 bits
57 */
58 #if BITS_PER_LONG == 64
59 #define NFT_PIPAPO_MAP_TOBITS 32
60 #else
61 #define NFT_PIPAPO_MAP_TOBITS (BITS_PER_LONG - NFT_PIPAPO_MAP_NBITS)
62 #endif
63
64 /* ...which gives us the highest allowed index for a rule */
65 #define NFT_PIPAPO_RULE0_MAX ((1UL << (NFT_PIPAPO_MAP_TOBITS - 1)) \
66 - (1UL << NFT_PIPAPO_MAP_NBITS))
67
68 /* Definitions for vectorised implementations */
69 #ifdef NFT_PIPAPO_ALIGN
70 #define NFT_PIPAPO_ALIGN_HEADROOM \
71 (NFT_PIPAPO_ALIGN - ARCH_KMALLOC_MINALIGN)
72 #define NFT_PIPAPO_LT_ALIGN(lt) (PTR_ALIGN((lt), NFT_PIPAPO_ALIGN))
73 #else
74 #define NFT_PIPAPO_ALIGN_HEADROOM 0
75 #define NFT_PIPAPO_LT_ALIGN(lt) (lt)
76 #endif /* NFT_PIPAPO_ALIGN */
77
78 #define nft_pipapo_for_each_field(field, index, match) \
79 for ((field) = (match)->f, (index) = 0; \
80 (index) < (match)->field_count; \
81 (index)++, (field)++)
82
83 /**
84 * union nft_pipapo_map_bucket - Bucket of mapping table
85 * @to: First rule number (in next field) this rule maps to
86 * @n: Number of rules (in next field) this rule maps to
87 * @e: If there's no next field, pointer to element this rule maps to
88 */
89 union nft_pipapo_map_bucket {
90 struct {
91 #if BITS_PER_LONG == 64
92 static_assert(NFT_PIPAPO_MAP_TOBITS <= 32);
93 u32 to;
94
95 static_assert(NFT_PIPAPO_MAP_NBITS <= 32);
96 u32 n;
97 #else
98 unsigned long to:NFT_PIPAPO_MAP_TOBITS;
99 unsigned long n:NFT_PIPAPO_MAP_NBITS;
100 #endif
101 };
102 struct nft_pipapo_elem *e;
103 };
104
105 /**
106 * struct nft_pipapo_field - Lookup, mapping tables and related data for a field
107 * @rules: Number of inserted rules
108 * @bsize: Size of each bucket in lookup table, in longs
109 * @rules_alloc: Number of allocated rules, always >= rules
110 * @groups: Amount of bit groups
111 * @bb: Number of bits grouped together in lookup table buckets
112 * @lt: Lookup table: 'groups' rows of buckets
113 * @mt: Mapping table: one bucket per rule
114 */
115 struct nft_pipapo_field {
116 unsigned int rules;
117 unsigned int bsize;
118 unsigned int rules_alloc;
119 u8 groups;
120 u8 bb;
121 unsigned long *lt;
122 union nft_pipapo_map_bucket *mt;
123 };
124
125 /**
126 * struct nft_pipapo_scratch - percpu data used for lookup and matching
127 * @bh_lock: PREEMPT_RT local spinlock
128 * @map_index: Current working bitmap index, toggled between field matches
129 * @__map: store partial matching results during lookup
130 */
131 struct nft_pipapo_scratch {
132 local_lock_t bh_lock;
133 u8 map_index;
134 unsigned long __map[];
135 };
136
137 /**
138 * struct nft_pipapo_match - Data used for lookup and matching
139 * @field_count: Amount of fields in set
140 * @bsize_max: Maximum lookup table bucket size of all fields, in longs
141 * @scratch: Preallocated per-CPU maps for partial matching results
142 * @rcu: Matching data is swapped on commits
143 * @f: Fields, with lookup and mapping tables
144 */
145 struct nft_pipapo_match {
146 u8 field_count;
147 unsigned int bsize_max;
148 struct nft_pipapo_scratch * __percpu *scratch;
149 struct rcu_head rcu;
150 struct nft_pipapo_field f[] __counted_by(field_count);
151 };
152
153 /**
154 * struct nft_pipapo - Representation of a set
155 * @match: Currently in-use matching data
156 * @clone: Copy where pending insertions and deletions are kept
157 * @width: Total bytes to be matched for one packet, including padding
158 * @last_gc: Timestamp of last garbage collection run, jiffies
159 * @gc_head: list of nft_trans_gc to queue up for mem reclaim
160 */
161 struct nft_pipapo {
162 struct nft_pipapo_match __rcu *match;
163 struct nft_pipapo_match *clone;
164 int width;
165 unsigned long last_gc;
166 struct list_head gc_head;
167 };
168
169 struct nft_pipapo_elem;
170
171 /**
172 * struct nft_pipapo_elem - API-facing representation of single set element
173 * @priv: element placeholder
174 * @ext: nftables API extensions
175 */
176 struct nft_pipapo_elem {
177 struct nft_elem_priv priv;
178 struct nft_set_ext ext;
179 };
180
181 int pipapo_refill(unsigned long *map, unsigned int len, unsigned int rules,
182 unsigned long *dst,
183 const union nft_pipapo_map_bucket *mt, bool match_only);
184
185 /**
186 * pipapo_and_field_buckets_4bit() - Intersect 4-bit buckets
187 * @f: Field including lookup table
188 * @dst: Area to store result
189 * @data: Input data selecting table buckets
190 */
pipapo_and_field_buckets_4bit(const struct nft_pipapo_field * f,unsigned long * dst,const u8 * data)191 static inline void pipapo_and_field_buckets_4bit(const struct nft_pipapo_field *f,
192 unsigned long *dst,
193 const u8 *data)
194 {
195 unsigned long *lt = NFT_PIPAPO_LT_ALIGN(f->lt);
196 int group;
197
198 for (group = 0; group < f->groups; group += BITS_PER_BYTE / 4, data++) {
199 u8 v;
200
201 v = *data >> 4;
202 __bitmap_and(dst, dst, lt + v * f->bsize,
203 f->bsize * BITS_PER_LONG);
204 lt += f->bsize * NFT_PIPAPO_BUCKETS(4);
205
206 v = *data & 0x0f;
207 __bitmap_and(dst, dst, lt + v * f->bsize,
208 f->bsize * BITS_PER_LONG);
209 lt += f->bsize * NFT_PIPAPO_BUCKETS(4);
210 }
211 }
212
213 /**
214 * pipapo_and_field_buckets_8bit() - Intersect 8-bit buckets
215 * @f: Field including lookup table
216 * @dst: Area to store result
217 * @data: Input data selecting table buckets
218 */
pipapo_and_field_buckets_8bit(const struct nft_pipapo_field * f,unsigned long * dst,const u8 * data)219 static inline void pipapo_and_field_buckets_8bit(const struct nft_pipapo_field *f,
220 unsigned long *dst,
221 const u8 *data)
222 {
223 unsigned long *lt = NFT_PIPAPO_LT_ALIGN(f->lt);
224 int group;
225
226 for (group = 0; group < f->groups; group++, data++) {
227 __bitmap_and(dst, dst, lt + *data * f->bsize,
228 f->bsize * BITS_PER_LONG);
229 lt += f->bsize * NFT_PIPAPO_BUCKETS(8);
230 }
231 }
232
233 /**
234 * pipapo_estimate_size() - Estimate worst-case for set size
235 * @desc: Set description, element count and field description used here
236 *
237 * The size for this set type can vary dramatically, as it depends on the number
238 * of rules (composing netmasks) the entries expand to. We compute the worst
239 * case here.
240 *
241 * In general, for a non-ranged entry or a single composing netmask, we need
242 * one bit in each of the sixteen NFT_PIPAPO_BUCKETS, for each 4-bit group (that
243 * is, each input bit needs four bits of matching data), plus a bucket in the
244 * mapping table for each field.
245 *
246 * Return: worst-case set size in bytes, 0 on any overflow
247 */
pipapo_estimate_size(const struct nft_set_desc * desc)248 static u64 pipapo_estimate_size(const struct nft_set_desc *desc)
249 {
250 unsigned long entry_size;
251 u64 size;
252 int i;
253
254 for (i = 0, entry_size = 0; i < desc->field_count; i++) {
255 unsigned long rules;
256
257 if (desc->field_len[i] > NFT_PIPAPO_MAX_BYTES)
258 return 0;
259
260 /* Worst-case ranges for each concatenated field: each n-bit
261 * field can expand to up to n * 2 rules in each bucket, and
262 * each rule also needs a mapping bucket.
263 */
264 rules = ilog2(desc->field_len[i] * BITS_PER_BYTE) * 2;
265 entry_size += rules *
266 NFT_PIPAPO_BUCKETS(NFT_PIPAPO_GROUP_BITS_INIT) /
267 BITS_PER_BYTE;
268 entry_size += rules * sizeof(union nft_pipapo_map_bucket);
269 }
270
271 /* Rules in lookup and mapping tables are needed for each entry */
272 size = desc->size * entry_size;
273 if (size && div_u64(size, desc->size) != entry_size)
274 return 0;
275
276 size += sizeof(struct nft_pipapo) + sizeof(struct nft_pipapo_match) * 2;
277
278 size += sizeof(struct nft_pipapo_field) * desc->field_count;
279
280 return size;
281 }
282
283 /**
284 * pipapo_resmap_init() - Initialise result map before first use
285 * @m: Matching data, including mapping table
286 * @res_map: Result map
287 *
288 * Initialize all bits covered by the first field to one, so that after
289 * the first step, only the matching bits of the first bit group remain.
290 *
291 * If other fields have a large bitmap, set remainder of res_map to 0.
292 */
pipapo_resmap_init(const struct nft_pipapo_match * m,unsigned long * res_map)293 static inline void pipapo_resmap_init(const struct nft_pipapo_match *m, unsigned long *res_map)
294 {
295 const struct nft_pipapo_field *f = m->f;
296 int i;
297
298 for (i = 0; i < f->bsize; i++)
299 res_map[i] = ULONG_MAX;
300
301 for (i = f->bsize; i < m->bsize_max; i++)
302 res_map[i] = 0ul;
303 }
304 #endif /* _NFT_SET_PIPAPO_H */
305