xref: /dpdk/lib/hash/rte_thash.c (revision 6e97b5fc)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2021 Intel Corporation
3  */
4 
5 #include <sys/queue.h>
6 
7 #include <rte_thash.h>
8 #include <rte_tailq.h>
9 #include <rte_random.h>
10 #include <rte_memcpy.h>
11 #include <rte_errno.h>
12 #include <rte_eal.h>
13 #include <rte_eal_memconfig.h>
14 #include <rte_log.h>
15 #include <rte_malloc.h>
16 
17 #define THASH_NAME_LEN		64
18 #define TOEPLITZ_HASH_LEN	32
19 
20 #define RETA_SZ_IN_RANGE(reta_sz)	((reta_sz >= RTE_THASH_RETA_SZ_MIN) &&\
21 					(reta_sz <= RTE_THASH_RETA_SZ_MAX))
22 
23 TAILQ_HEAD(rte_thash_list, rte_tailq_entry);
24 static struct rte_tailq_elem rte_thash_tailq = {
25 	.name = "RTE_THASH",
26 };
27 EAL_REGISTER_TAILQ(rte_thash_tailq)
28 
29 /**
30  * Table of some irreducible polinomials over GF(2).
31  * For lfsr they are represented in BE bit order, and
32  * x^0 is masked out.
33  * For example, poly x^5 + x^2 + 1 will be represented
34  * as (101001b & 11111b) = 01001b = 0x9
35  */
36 static const uint32_t irreducible_poly_table[][4] = {
37 	{0, 0, 0, 0},	/** < degree 0 */
38 	{1, 1, 1, 1},	/** < degree 1 */
39 	{0x3, 0x3, 0x3, 0x3},	/** < degree 2 and so on... */
40 	{0x5, 0x3, 0x5, 0x3},
41 	{0x9, 0x3, 0x9, 0x3},
42 	{0x9, 0x1b, 0xf, 0x5},
43 	{0x21, 0x33, 0x1b, 0x2d},
44 	{0x41, 0x11, 0x71, 0x9},
45 	{0x71, 0xa9, 0xf5, 0x8d},
46 	{0x21, 0xd1, 0x69, 0x1d9},
47 	{0x81, 0x2c1, 0x3b1, 0x185},
48 	{0x201, 0x541, 0x341, 0x461},
49 	{0x941, 0x609, 0xe19, 0x45d},
50 	{0x1601, 0x1f51, 0x1171, 0x359},
51 	{0x2141, 0x2111, 0x2db1, 0x2109},
52 	{0x4001, 0x801, 0x101, 0x7301},
53 	{0x7781, 0xa011, 0x4211, 0x86d9},
54 };
55 
56 struct thash_lfsr {
57 	uint32_t	ref_cnt;
58 	uint32_t	poly;
59 	/**< polynomial associated with the lfsr */
60 	uint32_t	rev_poly;
61 	/**< polynomial to generate the sequence in reverse direction */
62 	uint32_t	state;
63 	/**< current state of the lfsr */
64 	uint32_t	rev_state;
65 	/**< current state of the lfsr for reverse direction */
66 	uint32_t	deg;	/**< polynomial degree*/
67 	uint32_t	bits_cnt;  /**< number of bits generated by lfsr*/
68 };
69 
70 struct rte_thash_subtuple_helper {
71 	char	name[THASH_NAME_LEN];	/** < Name of subtuple configuration */
72 	LIST_ENTRY(rte_thash_subtuple_helper)	next;
73 	struct thash_lfsr	*lfsr;
74 	uint32_t	offset;		/** < Offset of the m-sequence */
75 	uint32_t	len;		/** < Length of the m-sequence */
76 	uint32_t	tuple_offset;	/** < Offset in bits of the subtuple */
77 	uint32_t	tuple_len;	/** < Length in bits of the subtuple */
78 	uint32_t	lsb_msk;	/** < (1 << reta_sz_log) - 1 */
79 	__extension__ uint32_t	compl_table[0] __rte_cache_aligned;
80 	/** < Complementary table */
81 };
82 
83 struct rte_thash_ctx {
84 	char		name[THASH_NAME_LEN];
85 	LIST_HEAD(, rte_thash_subtuple_helper) head;
86 	uint32_t	key_len;	/** < Length of the NIC RSS hash key */
87 	uint32_t	reta_sz_log;	/** < size of the RSS ReTa in bits */
88 	uint32_t	subtuples_nb;	/** < number of subtuples */
89 	uint32_t	flags;
90 	uint64_t	*matrices;
91 	/**< matrices used with rte_thash_gfni implementation */
92 	uint8_t		hash_key[0];
93 };
94 
95 int
96 rte_thash_gfni_supported(void)
97 {
98 #ifdef RTE_THASH_GFNI_DEFINED
99 	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_GFNI) &&
100 			(rte_vect_get_max_simd_bitwidth() >=
101 			RTE_VECT_SIMD_512))
102 		return 1;
103 #endif
104 
105 	return 0;
106 };
107 
108 void
109 rte_thash_complete_matrix(uint64_t *matrixes, const uint8_t *rss_key, int size)
110 {
111 	int i, j;
112 	uint8_t *m = (uint8_t *)matrixes;
113 	uint8_t left_part, right_part;
114 
115 	for (i = 0; i < size; i++) {
116 		for (j = 0; j < 8; j++) {
117 			left_part = rss_key[i] << j;
118 			right_part = (uint16_t)(rss_key[(i + 1) % size]) >>
119 				(8 - j);
120 			m[i * 8 + j] = left_part|right_part;
121 		}
122 	}
123 }
124 
125 static inline uint32_t
126 get_bit_lfsr(struct thash_lfsr *lfsr)
127 {
128 	uint32_t bit, ret;
129 
130 	/*
131 	 * masking the TAP bits defined by the polynomial and
132 	 * calculating parity
133 	 */
134 	bit = __builtin_popcount(lfsr->state & lfsr->poly) & 0x1;
135 	ret = lfsr->state & 0x1;
136 	lfsr->state = ((lfsr->state >> 1) | (bit << (lfsr->deg - 1))) &
137 		((1 << lfsr->deg) - 1);
138 
139 	lfsr->bits_cnt++;
140 	return ret;
141 }
142 
143 static inline uint32_t
144 get_rev_bit_lfsr(struct thash_lfsr *lfsr)
145 {
146 	uint32_t bit, ret;
147 
148 	bit = __builtin_popcount(lfsr->rev_state & lfsr->rev_poly) & 0x1;
149 	ret = lfsr->rev_state & (1 << (lfsr->deg - 1));
150 	lfsr->rev_state = ((lfsr->rev_state << 1) | bit) &
151 		((1 << lfsr->deg) - 1);
152 
153 	lfsr->bits_cnt++;
154 	return ret;
155 }
156 
157 static inline uint32_t
158 thash_get_rand_poly(uint32_t poly_degree)
159 {
160 	return irreducible_poly_table[poly_degree][rte_rand() %
161 		RTE_DIM(irreducible_poly_table[poly_degree])];
162 }
163 
164 static struct thash_lfsr *
165 alloc_lfsr(struct rte_thash_ctx *ctx)
166 {
167 	struct thash_lfsr *lfsr;
168 	uint32_t i;
169 
170 	if (ctx == NULL)
171 		return NULL;
172 
173 	lfsr = rte_zmalloc(NULL, sizeof(struct thash_lfsr), 0);
174 	if (lfsr == NULL)
175 		return NULL;
176 
177 	lfsr->deg = ctx->reta_sz_log;
178 	lfsr->poly = thash_get_rand_poly(lfsr->deg);
179 	do {
180 		lfsr->state = rte_rand() & ((1 << lfsr->deg) - 1);
181 	} while (lfsr->state == 0);
182 	/* init reverse order polynomial */
183 	lfsr->rev_poly = (lfsr->poly >> 1) | (1 << (lfsr->deg - 1));
184 	/* init proper rev_state*/
185 	lfsr->rev_state = lfsr->state;
186 	for (i = 0; i <= lfsr->deg; i++)
187 		get_rev_bit_lfsr(lfsr);
188 
189 	/* clear bits_cnt after rev_state was inited */
190 	lfsr->bits_cnt = 0;
191 	lfsr->ref_cnt = 1;
192 
193 	return lfsr;
194 }
195 
196 static void
197 attach_lfsr(struct rte_thash_subtuple_helper *h, struct thash_lfsr *lfsr)
198 {
199 	lfsr->ref_cnt++;
200 	h->lfsr = lfsr;
201 }
202 
203 static void
204 free_lfsr(struct thash_lfsr *lfsr)
205 {
206 	lfsr->ref_cnt--;
207 	if (lfsr->ref_cnt == 0)
208 		rte_free(lfsr);
209 }
210 
211 struct rte_thash_ctx *
212 rte_thash_init_ctx(const char *name, uint32_t key_len, uint32_t reta_sz,
213 	uint8_t *key, uint32_t flags)
214 {
215 	struct rte_thash_ctx *ctx;
216 	struct rte_tailq_entry *te;
217 	struct rte_thash_list *thash_list;
218 	uint32_t i;
219 
220 	if ((name == NULL) || (key_len == 0) || !RETA_SZ_IN_RANGE(reta_sz)) {
221 		rte_errno = EINVAL;
222 		return NULL;
223 	}
224 
225 	thash_list = RTE_TAILQ_CAST(rte_thash_tailq.head, rte_thash_list);
226 
227 	rte_mcfg_tailq_write_lock();
228 
229 	/* guarantee there's no existing */
230 	TAILQ_FOREACH(te, thash_list, next) {
231 		ctx = (struct rte_thash_ctx *)te->data;
232 		if (strncmp(name, ctx->name, sizeof(ctx->name)) == 0)
233 			break;
234 	}
235 	ctx = NULL;
236 	if (te != NULL) {
237 		rte_errno = EEXIST;
238 		goto exit;
239 	}
240 
241 	/* allocate tailq entry */
242 	te = rte_zmalloc("THASH_TAILQ_ENTRY", sizeof(*te), 0);
243 	if (te == NULL) {
244 		RTE_LOG(ERR, HASH,
245 			"Can not allocate tailq entry for thash context %s\n",
246 			name);
247 		rte_errno = ENOMEM;
248 		goto exit;
249 	}
250 
251 	ctx = rte_zmalloc(NULL, sizeof(struct rte_thash_ctx) + key_len, 0);
252 	if (ctx == NULL) {
253 		RTE_LOG(ERR, HASH, "thash ctx %s memory allocation failed\n",
254 			name);
255 		rte_errno = ENOMEM;
256 		goto free_te;
257 	}
258 
259 	rte_strlcpy(ctx->name, name, sizeof(ctx->name));
260 	ctx->key_len = key_len;
261 	ctx->reta_sz_log = reta_sz;
262 	LIST_INIT(&ctx->head);
263 	ctx->flags = flags;
264 
265 	if (key)
266 		rte_memcpy(ctx->hash_key, key, key_len);
267 	else {
268 		for (i = 0; i < key_len; i++)
269 			ctx->hash_key[i] = rte_rand();
270 	}
271 
272 	if (rte_thash_gfni_supported()) {
273 		ctx->matrices = rte_zmalloc(NULL, key_len * sizeof(uint64_t),
274 			RTE_CACHE_LINE_SIZE);
275 		if (ctx->matrices == NULL) {
276 			RTE_LOG(ERR, HASH, "Cannot allocate matrices\n");
277 			rte_errno = ENOMEM;
278 			goto free_ctx;
279 		}
280 
281 		rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
282 			key_len);
283 	}
284 
285 	te->data = (void *)ctx;
286 	TAILQ_INSERT_TAIL(thash_list, te, next);
287 
288 	rte_mcfg_tailq_write_unlock();
289 
290 	return ctx;
291 
292 free_ctx:
293 	rte_free(ctx);
294 free_te:
295 	rte_free(te);
296 exit:
297 	rte_mcfg_tailq_write_unlock();
298 	return NULL;
299 }
300 
301 struct rte_thash_ctx *
302 rte_thash_find_existing(const char *name)
303 {
304 	struct rte_thash_ctx *ctx;
305 	struct rte_tailq_entry *te;
306 	struct rte_thash_list *thash_list;
307 
308 	thash_list = RTE_TAILQ_CAST(rte_thash_tailq.head, rte_thash_list);
309 
310 	rte_mcfg_tailq_read_lock();
311 	TAILQ_FOREACH(te, thash_list, next) {
312 		ctx = (struct rte_thash_ctx *)te->data;
313 		if (strncmp(name, ctx->name, sizeof(ctx->name)) == 0)
314 			break;
315 	}
316 
317 	rte_mcfg_tailq_read_unlock();
318 
319 	if (te == NULL) {
320 		rte_errno = ENOENT;
321 		return NULL;
322 	}
323 
324 	return ctx;
325 }
326 
327 void
328 rte_thash_free_ctx(struct rte_thash_ctx *ctx)
329 {
330 	struct rte_tailq_entry *te;
331 	struct rte_thash_list *thash_list;
332 	struct rte_thash_subtuple_helper *ent, *tmp;
333 
334 	if (ctx == NULL)
335 		return;
336 
337 	thash_list = RTE_TAILQ_CAST(rte_thash_tailq.head, rte_thash_list);
338 	rte_mcfg_tailq_write_lock();
339 	TAILQ_FOREACH(te, thash_list, next) {
340 		if (te->data == (void *)ctx)
341 			break;
342 	}
343 
344 	if (te != NULL)
345 		TAILQ_REMOVE(thash_list, te, next);
346 
347 	rte_mcfg_tailq_write_unlock();
348 	ent = LIST_FIRST(&(ctx->head));
349 	while (ent) {
350 		free_lfsr(ent->lfsr);
351 		tmp = ent;
352 		ent = LIST_NEXT(ent, next);
353 		LIST_REMOVE(tmp, next);
354 		rte_free(tmp);
355 	}
356 
357 	rte_free(ctx);
358 	rte_free(te);
359 }
360 
361 static inline void
362 set_bit(uint8_t *ptr, uint32_t bit, uint32_t pos)
363 {
364 	uint32_t byte_idx = pos / CHAR_BIT;
365 	/* index of the bit int byte, indexing starts from MSB */
366 	uint32_t bit_idx = (CHAR_BIT - 1) - (pos & (CHAR_BIT - 1));
367 	uint8_t tmp;
368 
369 	tmp = ptr[byte_idx];
370 	tmp &= ~(1 << bit_idx);
371 	tmp |= bit << bit_idx;
372 	ptr[byte_idx] = tmp;
373 }
374 
375 /**
376  * writes m-sequence to the hash_key for range [start, end]
377  * (i.e. including start and end positions)
378  */
379 static int
380 generate_subkey(struct rte_thash_ctx *ctx, struct thash_lfsr *lfsr,
381 	uint32_t start, uint32_t end)
382 {
383 	uint32_t i;
384 	uint32_t req_bits = (start < end) ? (end - start) : (start - end);
385 	req_bits++; /* due to including end */
386 
387 	/* check if lfsr overflow period of the m-sequence */
388 	if (((lfsr->bits_cnt + req_bits) > (1ULL << lfsr->deg) - 1) &&
389 			((ctx->flags & RTE_THASH_IGNORE_PERIOD_OVERFLOW) !=
390 			RTE_THASH_IGNORE_PERIOD_OVERFLOW)) {
391 		RTE_LOG(ERR, HASH,
392 			"Can't generate m-sequence due to period overflow\n");
393 		return -ENOSPC;
394 	}
395 
396 	if (start < end) {
397 		/* original direction (from left to right)*/
398 		for (i = start; i <= end; i++)
399 			set_bit(ctx->hash_key, get_bit_lfsr(lfsr), i);
400 
401 	} else {
402 		/* reverse direction (from right to left) */
403 		for (i = end; i >= start; i--)
404 			set_bit(ctx->hash_key, get_rev_bit_lfsr(lfsr), i);
405 	}
406 
407 	if (ctx->matrices != NULL)
408 		rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
409 			ctx->key_len);
410 
411 	return 0;
412 }
413 
414 static inline uint32_t
415 get_subvalue(struct rte_thash_ctx *ctx, uint32_t offset)
416 {
417 	uint32_t *tmp, val;
418 
419 	tmp = (uint32_t *)(&ctx->hash_key[offset >> 3]);
420 	val = rte_be_to_cpu_32(*tmp);
421 	val >>= (TOEPLITZ_HASH_LEN - ((offset & (CHAR_BIT - 1)) +
422 		ctx->reta_sz_log));
423 
424 	return val & ((1 << ctx->reta_sz_log) - 1);
425 }
426 
427 static inline void
428 generate_complement_table(struct rte_thash_ctx *ctx,
429 	struct rte_thash_subtuple_helper *h)
430 {
431 	int i, j, k;
432 	uint32_t val;
433 	uint32_t start;
434 
435 	start = h->offset + h->len - (2 * ctx->reta_sz_log - 1);
436 
437 	for (i = 1; i < (1 << ctx->reta_sz_log); i++) {
438 		val = 0;
439 		for (j = i; j; j &= (j - 1)) {
440 			k = rte_bsf32(j);
441 			val ^= get_subvalue(ctx, start - k +
442 				ctx->reta_sz_log - 1);
443 		}
444 		h->compl_table[val] = i;
445 	}
446 }
447 
448 static inline int
449 insert_before(struct rte_thash_ctx *ctx,
450 	struct rte_thash_subtuple_helper *ent,
451 	struct rte_thash_subtuple_helper *cur_ent,
452 	struct rte_thash_subtuple_helper *next_ent,
453 	uint32_t start, uint32_t end, uint32_t range_end)
454 {
455 	int ret;
456 
457 	if (end < cur_ent->offset) {
458 		ent->lfsr = alloc_lfsr(ctx);
459 		if (ent->lfsr == NULL) {
460 			rte_free(ent);
461 			return -ENOMEM;
462 		}
463 		/* generate nonoverlapping range [start, end) */
464 		ret = generate_subkey(ctx, ent->lfsr, start, end - 1);
465 		if (ret != 0) {
466 			free_lfsr(ent->lfsr);
467 			rte_free(ent);
468 			return ret;
469 		}
470 	} else if ((next_ent != NULL) && (end > next_ent->offset)) {
471 		RTE_LOG(ERR, HASH,
472 			"Can't add helper %s due to conflict with existing"
473 			" helper %s\n", ent->name, next_ent->name);
474 		rte_free(ent);
475 		return -ENOSPC;
476 	}
477 	attach_lfsr(ent, cur_ent->lfsr);
478 
479 	/**
480 	 * generate partially overlapping range
481 	 * [start, cur_ent->start) in reverse order
482 	 */
483 	ret = generate_subkey(ctx, ent->lfsr, cur_ent->offset - 1, start);
484 	if (ret != 0) {
485 		free_lfsr(ent->lfsr);
486 		rte_free(ent);
487 		return ret;
488 	}
489 
490 	if (end > range_end) {
491 		/**
492 		 * generate partially overlapping range
493 		 * (range_end, end)
494 		 */
495 		ret = generate_subkey(ctx, ent->lfsr, range_end, end - 1);
496 		if (ret != 0) {
497 			free_lfsr(ent->lfsr);
498 			rte_free(ent);
499 			return ret;
500 		}
501 	}
502 
503 	LIST_INSERT_BEFORE(cur_ent, ent, next);
504 	generate_complement_table(ctx, ent);
505 	ctx->subtuples_nb++;
506 	return 0;
507 }
508 
509 static inline int
510 insert_after(struct rte_thash_ctx *ctx,
511 	struct rte_thash_subtuple_helper *ent,
512 	struct rte_thash_subtuple_helper *cur_ent,
513 	struct rte_thash_subtuple_helper *next_ent,
514 	struct rte_thash_subtuple_helper *prev_ent,
515 	uint32_t end, uint32_t range_end)
516 {
517 	int ret;
518 
519 	if ((next_ent != NULL) && (end > next_ent->offset)) {
520 		RTE_LOG(ERR, HASH,
521 			"Can't add helper %s due to conflict with existing"
522 			" helper %s\n", ent->name, next_ent->name);
523 		rte_free(ent);
524 		return -EEXIST;
525 	}
526 
527 	attach_lfsr(ent, cur_ent->lfsr);
528 	if (end > range_end) {
529 		/**
530 		 * generate partially overlapping range
531 		 * (range_end, end)
532 		 */
533 		ret = generate_subkey(ctx, ent->lfsr, range_end, end - 1);
534 		if (ret != 0) {
535 			free_lfsr(ent->lfsr);
536 			rte_free(ent);
537 			return ret;
538 		}
539 	}
540 
541 	LIST_INSERT_AFTER(prev_ent, ent, next);
542 	generate_complement_table(ctx, ent);
543 	ctx->subtuples_nb++;
544 
545 	return 0;
546 }
547 
548 int
549 rte_thash_add_helper(struct rte_thash_ctx *ctx, const char *name, uint32_t len,
550 	uint32_t offset)
551 {
552 	struct rte_thash_subtuple_helper *ent, *cur_ent, *prev_ent, *next_ent;
553 	uint32_t start, end;
554 	int ret;
555 
556 	if ((ctx == NULL) || (name == NULL) || (len < ctx->reta_sz_log) ||
557 			((offset + len + TOEPLITZ_HASH_LEN - 1) >
558 			ctx->key_len * CHAR_BIT))
559 		return -EINVAL;
560 
561 	/* Check for existing name*/
562 	LIST_FOREACH(cur_ent, &ctx->head, next) {
563 		if (strncmp(name, cur_ent->name, sizeof(cur_ent->name)) == 0)
564 			return -EEXIST;
565 	}
566 
567 	end = offset + len + TOEPLITZ_HASH_LEN - 1;
568 	start = ((ctx->flags & RTE_THASH_MINIMAL_SEQ) ==
569 		RTE_THASH_MINIMAL_SEQ) ? (end - (2 * ctx->reta_sz_log - 1)) :
570 		offset;
571 
572 	ent = rte_zmalloc(NULL, sizeof(struct rte_thash_subtuple_helper) +
573 		sizeof(uint32_t) * (1 << ctx->reta_sz_log),
574 		RTE_CACHE_LINE_SIZE);
575 	if (ent == NULL)
576 		return -ENOMEM;
577 
578 	rte_strlcpy(ent->name, name, sizeof(ent->name));
579 	ent->offset = start;
580 	ent->len = end - start;
581 	ent->tuple_offset = offset;
582 	ent->tuple_len = len;
583 	ent->lsb_msk = (1 << ctx->reta_sz_log) - 1;
584 
585 	cur_ent = LIST_FIRST(&ctx->head);
586 	while (cur_ent) {
587 		uint32_t range_end = cur_ent->offset + cur_ent->len;
588 		next_ent = LIST_NEXT(cur_ent, next);
589 		prev_ent = cur_ent;
590 		/* Iterate through overlapping ranges */
591 		while ((next_ent != NULL) && (next_ent->offset < range_end)) {
592 			range_end = RTE_MAX(next_ent->offset + next_ent->len,
593 				range_end);
594 			if (start > next_ent->offset)
595 				prev_ent = next_ent;
596 
597 			next_ent = LIST_NEXT(next_ent, next);
598 		}
599 
600 		if (start < cur_ent->offset)
601 			return insert_before(ctx, ent, cur_ent, next_ent,
602 				start, end, range_end);
603 		else if (start < range_end)
604 			return insert_after(ctx, ent, cur_ent, next_ent,
605 				prev_ent, end, range_end);
606 
607 		cur_ent = next_ent;
608 		continue;
609 	}
610 
611 	ent->lfsr = alloc_lfsr(ctx);
612 	if (ent->lfsr == NULL) {
613 		rte_free(ent);
614 		return -ENOMEM;
615 	}
616 
617 	/* generate nonoverlapping range [start, end) */
618 	ret = generate_subkey(ctx, ent->lfsr, start, end - 1);
619 	if (ret != 0) {
620 		free_lfsr(ent->lfsr);
621 		rte_free(ent);
622 		return ret;
623 	}
624 	if (LIST_EMPTY(&ctx->head)) {
625 		LIST_INSERT_HEAD(&ctx->head, ent, next);
626 	} else {
627 		LIST_FOREACH(next_ent, &ctx->head, next)
628 			prev_ent = next_ent;
629 
630 		LIST_INSERT_AFTER(prev_ent, ent, next);
631 	}
632 	generate_complement_table(ctx, ent);
633 	ctx->subtuples_nb++;
634 
635 	return 0;
636 }
637 
638 struct rte_thash_subtuple_helper *
639 rte_thash_get_helper(struct rte_thash_ctx *ctx, const char *name)
640 {
641 	struct rte_thash_subtuple_helper *ent;
642 
643 	if ((ctx == NULL) || (name == NULL))
644 		return NULL;
645 
646 	LIST_FOREACH(ent, &ctx->head, next) {
647 		if (strncmp(name, ent->name, sizeof(ent->name)) == 0)
648 			return ent;
649 	}
650 
651 	return NULL;
652 }
653 
654 uint32_t
655 rte_thash_get_complement(struct rte_thash_subtuple_helper *h,
656 	uint32_t hash, uint32_t desired_hash)
657 {
658 	return h->compl_table[(hash ^ desired_hash) & h->lsb_msk];
659 }
660 
661 const uint8_t *
662 rte_thash_get_key(struct rte_thash_ctx *ctx)
663 {
664 	return ctx->hash_key;
665 }
666 
667 const uint64_t *
668 rte_thash_get_gfni_matrices(struct rte_thash_ctx *ctx)
669 {
670 	return ctx->matrices;
671 }
672 
673 static inline uint8_t
674 read_unaligned_byte(uint8_t *ptr, unsigned int len, unsigned int offset)
675 {
676 	uint8_t ret = 0;
677 
678 	ret = ptr[offset / CHAR_BIT];
679 	if (offset % CHAR_BIT) {
680 		ret <<= (offset % CHAR_BIT);
681 		ret |= ptr[(offset / CHAR_BIT) + 1] >>
682 			(CHAR_BIT - (offset % CHAR_BIT));
683 	}
684 
685 	return ret >> (CHAR_BIT - len);
686 }
687 
688 static inline uint32_t
689 read_unaligned_bits(uint8_t *ptr, int len, int offset)
690 {
691 	uint32_t ret = 0;
692 
693 	len = RTE_MAX(len, 0);
694 	len = RTE_MIN(len, (int)(sizeof(uint32_t) * CHAR_BIT));
695 
696 	while (len > 0) {
697 		ret <<= CHAR_BIT;
698 
699 		ret |= read_unaligned_byte(ptr, RTE_MIN(len, CHAR_BIT),
700 			offset);
701 		offset += CHAR_BIT;
702 		len -= CHAR_BIT;
703 	}
704 
705 	return ret;
706 }
707 
708 /* returns mask for len bits with given offset inside byte */
709 static inline uint8_t
710 get_bits_mask(unsigned int len, unsigned int offset)
711 {
712 	unsigned int last_bit;
713 
714 	offset %= CHAR_BIT;
715 	/* last bit within byte */
716 	last_bit = RTE_MIN((unsigned int)CHAR_BIT, offset + len);
717 
718 	return ((1 << (CHAR_BIT - offset)) - 1) ^
719 		((1 << (CHAR_BIT - last_bit)) - 1);
720 }
721 
722 static inline void
723 write_unaligned_byte(uint8_t *ptr, unsigned int len,
724 	unsigned int offset, uint8_t val)
725 {
726 	uint8_t tmp;
727 
728 	tmp = ptr[offset / CHAR_BIT];
729 	tmp &= ~get_bits_mask(len, offset);
730 	tmp |= ((val << (CHAR_BIT - len)) >> (offset % CHAR_BIT));
731 	ptr[offset / CHAR_BIT] = tmp;
732 	if (((offset + len) / CHAR_BIT) != (offset / CHAR_BIT)) {
733 		int rest_len = (offset + len) % CHAR_BIT;
734 		tmp = ptr[(offset + len) / CHAR_BIT];
735 		tmp &= ~get_bits_mask(rest_len, 0);
736 		tmp |= val << (CHAR_BIT - rest_len);
737 		ptr[(offset + len) / CHAR_BIT] = tmp;
738 	}
739 }
740 
741 static inline void
742 write_unaligned_bits(uint8_t *ptr, int len, int offset, uint32_t val)
743 {
744 	uint8_t tmp;
745 	unsigned int part_len;
746 
747 	len = RTE_MAX(len, 0);
748 	len = RTE_MIN(len, (int)(sizeof(uint32_t) * CHAR_BIT));
749 
750 	while (len > 0) {
751 		part_len = RTE_MIN(CHAR_BIT, len);
752 		tmp = (uint8_t)val & ((1 << part_len) - 1);
753 		write_unaligned_byte(ptr, part_len,
754 			offset + len - part_len, tmp);
755 		len -= CHAR_BIT;
756 		val >>= CHAR_BIT;
757 	}
758 }
759 
760 int
761 rte_thash_adjust_tuple(struct rte_thash_ctx *ctx,
762 	struct rte_thash_subtuple_helper *h,
763 	uint8_t *tuple, unsigned int tuple_len,
764 	uint32_t desired_value,	unsigned int attempts,
765 	rte_thash_check_tuple_t fn, void *userdata)
766 {
767 	uint32_t tmp_tuple[tuple_len / sizeof(uint32_t)];
768 	unsigned int i, j, ret = 0;
769 	uint32_t hash, adj_bits;
770 	const uint8_t *hash_key;
771 	uint32_t tmp;
772 	int offset;
773 	int tmp_len;
774 
775 	if ((ctx == NULL) || (h == NULL) || (tuple == NULL) ||
776 			(tuple_len % sizeof(uint32_t) != 0) || (attempts <= 0))
777 		return -EINVAL;
778 
779 	hash_key = rte_thash_get_key(ctx);
780 
781 	attempts = RTE_MIN(attempts, 1U << (h->tuple_len - ctx->reta_sz_log));
782 
783 	for (i = 0; i < attempts; i++) {
784 		if (ctx->matrices != NULL)
785 			hash = rte_thash_gfni(ctx->matrices, tuple, tuple_len);
786 		else {
787 			for (j = 0; j < (tuple_len / 4); j++)
788 				tmp_tuple[j] =
789 					rte_be_to_cpu_32(
790 						*(uint32_t *)&tuple[j * 4]);
791 
792 			hash = rte_softrss(tmp_tuple, tuple_len / 4, hash_key);
793 		}
794 
795 		adj_bits = rte_thash_get_complement(h, hash, desired_value);
796 
797 		/*
798 		 * Hint: LSB of adj_bits corresponds to
799 		 * offset + len bit of the subtuple
800 		 */
801 		offset =  h->tuple_offset + h->tuple_len - ctx->reta_sz_log;
802 		tmp = read_unaligned_bits(tuple, ctx->reta_sz_log, offset);
803 		tmp ^= adj_bits;
804 		write_unaligned_bits(tuple, ctx->reta_sz_log, offset, tmp);
805 
806 		if (fn != NULL) {
807 			ret = (fn(userdata, tuple)) ? 0 : -EEXIST;
808 			if (ret == 0)
809 				return 0;
810 			else if (i < (attempts - 1)) {
811 				/* increment subtuple part by 1 */
812 				tmp_len = RTE_MIN(sizeof(uint32_t) * CHAR_BIT,
813 					h->tuple_len - ctx->reta_sz_log);
814 				offset -= tmp_len;
815 				tmp = read_unaligned_bits(tuple, tmp_len,
816 					offset);
817 				tmp++;
818 				tmp &= (1 << tmp_len) - 1;
819 				write_unaligned_bits(tuple, tmp_len, offset,
820 					tmp);
821 			}
822 		} else
823 			return 0;
824 	}
825 
826 	return ret;
827 }
828