xref: /linux/net/ethtool/bitset.c (revision 91a4855d6c03e770e42f17c798a36a3c46e63de2)
1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/ethtool_netlink.h>
4 #include <linux/bitmap.h>
5 
6 #include "bitset.h"
7 #include "netlink.h"
8 
9 /* Some bitmaps are internally represented as an array of unsigned long, some
10  * as an array of u32 (some even as single u32 for now). To avoid the need of
11  * wrappers on caller side, we provide two set of functions: those with "32"
12  * suffix in their names expect u32 based bitmaps, those without it expect
13  * unsigned long bitmaps.
14  */
15 
16 static u32 ethnl_lower_bits(unsigned int n)
17 {
18 	return ~(u32)0 >> (32 - n % 32);
19 }
20 
21 static u32 ethnl_upper_bits(unsigned int n)
22 {
23 	return ~(u32)0 << (n % 32);
24 }
25 
26 /**
27  * ethnl_bitmap32_clear() - Clear u32 based bitmap
28  * @dst:   bitmap to clear
29  * @start: beginning of the interval
30  * @end:   end of the interval
31  * @mod:   set if bitmap was modified
32  *
33  * Clear @nbits bits of a bitmap with indices @start <= i < @end
34  */
35 static void ethnl_bitmap32_clear(u32 *dst, unsigned int start, unsigned int end,
36 				 bool *mod)
37 {
38 	unsigned int start_word = start / 32;
39 	unsigned int end_word = end / 32;
40 	unsigned int i;
41 	u32 mask;
42 
43 	if (end <= start)
44 		return;
45 
46 	if (start % 32) {
47 		mask = ethnl_upper_bits(start);
48 		if (end_word == start_word) {
49 			mask &= ethnl_lower_bits(end);
50 			if (dst[start_word] & mask) {
51 				dst[start_word] &= ~mask;
52 				*mod = true;
53 			}
54 			return;
55 		}
56 		if (dst[start_word] & mask) {
57 			dst[start_word] &= ~mask;
58 			*mod = true;
59 		}
60 		start_word++;
61 	}
62 
63 	for (i = start_word; i < end_word; i++) {
64 		if (dst[i]) {
65 			dst[i] = 0;
66 			*mod = true;
67 		}
68 	}
69 	if (end % 32) {
70 		mask = ethnl_lower_bits(end);
71 		if (dst[end_word] & mask) {
72 			dst[end_word] &= ~mask;
73 			*mod = true;
74 		}
75 	}
76 }
77 
78 /**
79  * ethnl_bitmap32_not_zero() - Check if any bit is set in an interval
80  * @map:   bitmap to test
81  * @start: beginning of the interval
82  * @end:   end of the interval
83  *
84  * Return: true if there is non-zero bit with  index @start <= i < @end,
85  *         false if the whole interval is zero
86  */
87 static bool ethnl_bitmap32_not_zero(const u32 *map, unsigned int start,
88 				    unsigned int end)
89 {
90 	unsigned int start_word = start / 32;
91 	unsigned int end_word = end / 32;
92 	u32 mask;
93 
94 	if (end <= start)
95 		return true;
96 
97 	if (start % 32) {
98 		mask = ethnl_upper_bits(start);
99 		if (end_word == start_word) {
100 			mask &= ethnl_lower_bits(end);
101 			return map[start_word] & mask;
102 		}
103 		if (map[start_word] & mask)
104 			return true;
105 		start_word++;
106 	}
107 
108 	if (!memchr_inv(map + start_word, '\0',
109 			(end_word - start_word) * sizeof(u32)))
110 		return true;
111 	if (end % 32 == 0)
112 		return true;
113 	return map[end_word] & ethnl_lower_bits(end);
114 }
115 
116 /**
117  * ethnl_bitmap32_update() - Modify u32 based bitmap according to value/mask
118  *			     pair
119  * @dst:   bitmap to update
120  * @nbits: bit size of the bitmap
121  * @value: values to set
122  * @mask:  mask of bits to set
123  * @mod:   set to true if bitmap is modified, preserve if not
124  *
125  * Set bits in @dst bitmap which are set in @mask to values from @value, leave
126  * the rest untouched. If destination bitmap was modified, set @mod to true,
127  * leave as it is if not.
128  */
129 static void ethnl_bitmap32_update(u32 *dst, unsigned int nbits,
130 				  const u32 *value, const u32 *mask, bool *mod)
131 {
132 	while (nbits > 0) {
133 		u32 real_mask = mask ? *mask : ~(u32)0;
134 		u32 new_value;
135 
136 		if (nbits < 32)
137 			real_mask &= ethnl_lower_bits(nbits);
138 		new_value = (*dst & ~real_mask) | (*value & real_mask);
139 		if (new_value != *dst) {
140 			*dst = new_value;
141 			*mod = true;
142 		}
143 
144 		if (nbits <= 32)
145 			break;
146 		dst++;
147 		nbits -= 32;
148 		value++;
149 		if (mask)
150 			mask++;
151 	}
152 }
153 
154 static bool ethnl_bitmap32_test_bit(const u32 *map, unsigned int index)
155 {
156 	return map[index / 32] & (1U << (index % 32));
157 }
158 
159 /**
160  * ethnl_bitset32_size() - Calculate size of bitset nested attribute
161  * @val:     value bitmap (u32 based)
162  * @mask:    mask bitmap (u32 based, optional)
163  * @nbits:   bit length of the bitset
164  * @names:   array of bit names (optional)
165  * @compact: assume compact format for output
166  *
167  * Estimate length of netlink attribute composed by a later call to
168  * ethnl_put_bitset32() call with the same arguments.
169  *
170  * Return: negative error code or attribute length estimate
171  */
172 int ethnl_bitset32_size(const u32 *val, const u32 *mask, unsigned int nbits,
173 			ethnl_string_array_t names, bool compact)
174 {
175 	unsigned int len = 0;
176 
177 	/* list flag */
178 	if (!mask)
179 		len += nla_total_size(sizeof(u32));
180 	/* size */
181 	len += nla_total_size(sizeof(u32));
182 
183 	if (compact) {
184 		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
185 
186 		/* value, mask */
187 		len += (mask ? 2 : 1) * nla_total_size(nwords * sizeof(u32));
188 	} else {
189 		unsigned int bits_len = 0;
190 		unsigned int bit_len, i;
191 
192 		for (i = 0; i < nbits; i++) {
193 			const char *name = names ? names[i] : NULL;
194 
195 			if (!ethnl_bitmap32_test_bit(mask ?: val, i))
196 				continue;
197 			/* index */
198 			bit_len = nla_total_size(sizeof(u32));
199 			/* name */
200 			if (name)
201 				bit_len += ethnl_strz_size(name);
202 			/* value */
203 			if (mask && ethnl_bitmap32_test_bit(val, i))
204 				bit_len += nla_total_size(0);
205 
206 			/* bit nest */
207 			bits_len += nla_total_size(bit_len);
208 		}
209 		/* bits nest */
210 		len += nla_total_size(bits_len);
211 	}
212 
213 	/* outermost nest */
214 	return nla_total_size(len);
215 }
216 
217 /**
218  * ethnl_put_bitset32() - Put a bitset nest into a message
219  * @skb:      skb with the message
220  * @attrtype: attribute type for the bitset nest
221  * @val:      value bitmap (u32 based)
222  * @mask:     mask bitmap (u32 based, optional)
223  * @nbits:    bit length of the bitset
224  * @names:    array of bit names (optional)
225  * @compact:  use compact format for the output
226  *
227  * Compose a nested attribute representing a bitset. If @mask is null, simple
228  * bitmap (bit list) is created, if @mask is provided, represent a value/mask
229  * pair. Bit names are only used in verbose mode and when provided by calller.
230  *
231  * Return: 0 on success, negative error value on error
232  */
233 int ethnl_put_bitset32(struct sk_buff *skb, int attrtype, const u32 *val,
234 		       const u32 *mask, unsigned int nbits,
235 		       ethnl_string_array_t names, bool compact)
236 {
237 	struct nlattr *nest;
238 	struct nlattr *attr;
239 
240 	nest = nla_nest_start(skb, attrtype);
241 	if (!nest)
242 		return -EMSGSIZE;
243 
244 	if (!mask && nla_put_flag(skb, ETHTOOL_A_BITSET_NOMASK))
245 		goto nla_put_failure;
246 	if (nla_put_u32(skb, ETHTOOL_A_BITSET_SIZE, nbits))
247 		goto nla_put_failure;
248 	if (compact) {
249 		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
250 		unsigned int nbytes = nwords * sizeof(u32);
251 		u32 *dst;
252 
253 		attr = nla_reserve(skb, ETHTOOL_A_BITSET_VALUE, nbytes);
254 		if (!attr)
255 			goto nla_put_failure;
256 		dst = nla_data(attr);
257 		memcpy(dst, val, nbytes);
258 		if (nbits % 32)
259 			dst[nwords - 1] &= ethnl_lower_bits(nbits);
260 
261 		if (mask) {
262 			attr = nla_reserve(skb, ETHTOOL_A_BITSET_MASK, nbytes);
263 			if (!attr)
264 				goto nla_put_failure;
265 			dst = nla_data(attr);
266 			memcpy(dst, mask, nbytes);
267 			if (nbits % 32)
268 				dst[nwords - 1] &= ethnl_lower_bits(nbits);
269 		}
270 	} else {
271 		struct nlattr *bits;
272 		unsigned int i;
273 
274 		bits = nla_nest_start(skb, ETHTOOL_A_BITSET_BITS);
275 		if (!bits)
276 			goto nla_put_failure;
277 		for (i = 0; i < nbits; i++) {
278 			const char *name = names ? names[i] : NULL;
279 
280 			if (!ethnl_bitmap32_test_bit(mask ?: val, i))
281 				continue;
282 			attr = nla_nest_start(skb, ETHTOOL_A_BITSET_BITS_BIT);
283 			if (!attr)
284 				goto nla_put_failure;
285 			if (nla_put_u32(skb, ETHTOOL_A_BITSET_BIT_INDEX, i))
286 				goto nla_put_failure;
287 			if (name &&
288 			    ethnl_put_strz(skb, ETHTOOL_A_BITSET_BIT_NAME, name))
289 				goto nla_put_failure;
290 			if (mask && ethnl_bitmap32_test_bit(val, i) &&
291 			    nla_put_flag(skb, ETHTOOL_A_BITSET_BIT_VALUE))
292 				goto nla_put_failure;
293 			nla_nest_end(skb, attr);
294 		}
295 		nla_nest_end(skb, bits);
296 	}
297 
298 	nla_nest_end(skb, nest);
299 	return 0;
300 
301 nla_put_failure:
302 	nla_nest_cancel(skb, nest);
303 	return -EMSGSIZE;
304 }
305 
306 static const struct nla_policy bitset_policy[] = {
307 	[ETHTOOL_A_BITSET_NOMASK]	= { .type = NLA_FLAG },
308 	[ETHTOOL_A_BITSET_SIZE]		= NLA_POLICY_MAX(NLA_U32,
309 							 ETHNL_MAX_BITSET_SIZE),
310 	[ETHTOOL_A_BITSET_BITS]		= { .type = NLA_NESTED },
311 	[ETHTOOL_A_BITSET_VALUE]	= { .type = NLA_BINARY },
312 	[ETHTOOL_A_BITSET_MASK]		= { .type = NLA_BINARY },
313 };
314 
315 static const struct nla_policy bit_policy[] = {
316 	[ETHTOOL_A_BITSET_BIT_INDEX]	= { .type = NLA_U32 },
317 	[ETHTOOL_A_BITSET_BIT_NAME]	= { .type = NLA_NUL_STRING },
318 	[ETHTOOL_A_BITSET_BIT_VALUE]	= { .type = NLA_FLAG },
319 };
320 
321 /**
322  * ethnl_bitset_is_compact() - check if bitset attribute represents a compact
323  *			       bitset
324  * @bitset:  nested attribute representing a bitset
325  * @compact: pointer for return value
326  *
327  * Return: 0 on success, negative error code on failure
328  */
329 int ethnl_bitset_is_compact(const struct nlattr *bitset, bool *compact)
330 {
331 	struct nlattr *tb[ARRAY_SIZE(bitset_policy)];
332 	int ret;
333 
334 	ret = nla_parse_nested(tb, ARRAY_SIZE(bitset_policy) - 1, bitset,
335 			       bitset_policy, NULL);
336 	if (ret < 0)
337 		return ret;
338 
339 	if (tb[ETHTOOL_A_BITSET_BITS]) {
340 		if (tb[ETHTOOL_A_BITSET_VALUE] || tb[ETHTOOL_A_BITSET_MASK])
341 			return -EINVAL;
342 		*compact = false;
343 		return 0;
344 	}
345 	if (!tb[ETHTOOL_A_BITSET_SIZE] || !tb[ETHTOOL_A_BITSET_VALUE])
346 		return -EINVAL;
347 
348 	*compact = true;
349 	return 0;
350 }
351 
352 /**
353  * ethnl_name_to_idx() - look up string index for a name
354  * @names:   array of ETH_GSTRING_LEN sized strings
355  * @n_names: number of strings in the array
356  * @name:    name to look up
357  *
358  * Return: index of the string if found, -ENOENT if not found
359  */
360 static int ethnl_name_to_idx(ethnl_string_array_t names, unsigned int n_names,
361 			     const char *name)
362 {
363 	unsigned int i;
364 
365 	if (!names)
366 		return -ENOENT;
367 
368 	for (i = 0; i < n_names; i++) {
369 		/* names[i] may not be null terminated */
370 		if (!strncmp(names[i], name, ETH_GSTRING_LEN) &&
371 		    strlen(name) <= ETH_GSTRING_LEN)
372 			return i;
373 	}
374 
375 	return -ENOENT;
376 }
377 
378 static int ethnl_parse_bit(unsigned int *index, bool *val, unsigned int nbits,
379 			   const struct nlattr *bit_attr, bool no_mask,
380 			   ethnl_string_array_t names,
381 			   struct netlink_ext_ack *extack)
382 {
383 	struct nlattr *tb[ARRAY_SIZE(bit_policy)];
384 	int ret, idx;
385 
386 	ret = nla_parse_nested(tb, ARRAY_SIZE(bit_policy) - 1, bit_attr,
387 			       bit_policy, extack);
388 	if (ret < 0)
389 		return ret;
390 
391 	if (tb[ETHTOOL_A_BITSET_BIT_INDEX]) {
392 		const char *name;
393 
394 		idx = nla_get_u32(tb[ETHTOOL_A_BITSET_BIT_INDEX]);
395 		if (idx >= nbits) {
396 			NL_SET_ERR_MSG_ATTR(extack,
397 					    tb[ETHTOOL_A_BITSET_BIT_INDEX],
398 					    "bit index too high");
399 			return -EOPNOTSUPP;
400 		}
401 		name = names ? names[idx] : NULL;
402 		if (tb[ETHTOOL_A_BITSET_BIT_NAME] && name &&
403 		    strncmp(nla_data(tb[ETHTOOL_A_BITSET_BIT_NAME]), name,
404 			    nla_len(tb[ETHTOOL_A_BITSET_BIT_NAME]))) {
405 			NL_SET_ERR_MSG_ATTR(extack, bit_attr,
406 					    "bit index and name mismatch");
407 			return -EINVAL;
408 		}
409 	} else if (tb[ETHTOOL_A_BITSET_BIT_NAME]) {
410 		idx = ethnl_name_to_idx(names, nbits,
411 					nla_data(tb[ETHTOOL_A_BITSET_BIT_NAME]));
412 		if (idx < 0) {
413 			NL_SET_ERR_MSG_ATTR(extack,
414 					    tb[ETHTOOL_A_BITSET_BIT_NAME],
415 					    "bit name not found");
416 			return -EOPNOTSUPP;
417 		}
418 	} else {
419 		NL_SET_ERR_MSG_ATTR(extack, bit_attr,
420 				    "neither bit index nor name specified");
421 		return -EINVAL;
422 	}
423 
424 	*index = idx;
425 	*val = no_mask || tb[ETHTOOL_A_BITSET_BIT_VALUE];
426 	return 0;
427 }
428 
429 /**
430  * ethnl_bitmap32_equal() - Compare two bitmaps
431  * @map1:  first bitmap
432  * @map2:  second bitmap
433  * @nbits: bit size to compare
434  *
435  * Return: true if first @nbits are equal, false if not
436  */
437 static bool ethnl_bitmap32_equal(const u32 *map1, const u32 *map2,
438 				 unsigned int nbits)
439 {
440 	if (memcmp(map1, map2, nbits / 32 * sizeof(u32)))
441 		return false;
442 	if (nbits % 32 == 0)
443 		return true;
444 	return !((map1[nbits / 32] ^ map2[nbits / 32]) &
445 		 ethnl_lower_bits(nbits % 32));
446 }
447 
448 static int
449 ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
450 			      const struct nlattr *attr, struct nlattr **tb,
451 			      ethnl_string_array_t names,
452 			      struct netlink_ext_ack *extack, bool *mod)
453 {
454 	u32 *saved_bitmap = NULL;
455 	struct nlattr *bit_attr;
456 	bool no_mask;
457 	int rem;
458 	int ret;
459 
460 	if (tb[ETHTOOL_A_BITSET_VALUE]) {
461 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],
462 				    "value only allowed in compact bitset");
463 		return -EINVAL;
464 	}
465 	if (tb[ETHTOOL_A_BITSET_MASK]) {
466 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
467 				    "mask only allowed in compact bitset");
468 		return -EINVAL;
469 	}
470 
471 	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
472 	if (no_mask) {
473 		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
474 		unsigned int nbytes = nwords * sizeof(u32);
475 		bool dummy;
476 
477 		/* The bitmap size is only the size of the map part without
478 		 * its mask part.
479 		 */
480 		saved_bitmap = kcalloc(nwords, sizeof(u32), GFP_KERNEL);
481 		if (!saved_bitmap)
482 			return -ENOMEM;
483 		memcpy(saved_bitmap, bitmap, nbytes);
484 		ethnl_bitmap32_clear(bitmap, 0, nbits, &dummy);
485 	}
486 
487 	nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) {
488 		bool old_val, new_val;
489 		unsigned int idx;
490 
491 		if (nla_type(bit_attr) != ETHTOOL_A_BITSET_BITS_BIT) {
492 			NL_SET_ERR_MSG_ATTR(extack, bit_attr,
493 					    "only ETHTOOL_A_BITSET_BITS_BIT allowed in ETHTOOL_A_BITSET_BITS");
494 			kfree(saved_bitmap);
495 			return -EINVAL;
496 		}
497 		ret = ethnl_parse_bit(&idx, &new_val, nbits, bit_attr, no_mask,
498 				      names, extack);
499 		if (ret < 0) {
500 			kfree(saved_bitmap);
501 			return ret;
502 		}
503 		old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32));
504 		if (new_val != old_val) {
505 			if (new_val)
506 				bitmap[idx / 32] |= ((u32)1 << (idx % 32));
507 			else
508 				bitmap[idx / 32] &= ~((u32)1 << (idx % 32));
509 			if (!no_mask)
510 				*mod = true;
511 		}
512 	}
513 
514 	if (no_mask && !ethnl_bitmap32_equal(saved_bitmap, bitmap, nbits))
515 		*mod = true;
516 
517 	kfree(saved_bitmap);
518 	return 0;
519 }
520 
521 static int ethnl_compact_sanity_checks(unsigned int nbits,
522 				       const struct nlattr *nest,
523 				       struct nlattr **tb,
524 				       struct netlink_ext_ack *extack)
525 {
526 	bool no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
527 	unsigned int attr_nbits, attr_nwords;
528 	const struct nlattr *test_attr;
529 
530 	if (no_mask && tb[ETHTOOL_A_BITSET_MASK]) {
531 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
532 				    "mask not allowed in list bitset");
533 		return -EINVAL;
534 	}
535 	if (!tb[ETHTOOL_A_BITSET_SIZE]) {
536 		NL_SET_ERR_MSG_ATTR(extack, nest,
537 				    "missing size in compact bitset");
538 		return -EINVAL;
539 	}
540 	if (!tb[ETHTOOL_A_BITSET_VALUE]) {
541 		NL_SET_ERR_MSG_ATTR(extack, nest,
542 				    "missing value in compact bitset");
543 		return -EINVAL;
544 	}
545 	if (!no_mask && !tb[ETHTOOL_A_BITSET_MASK]) {
546 		NL_SET_ERR_MSG_ATTR(extack, nest,
547 				    "missing mask in compact nonlist bitset");
548 		return -EINVAL;
549 	}
550 
551 	attr_nbits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]);
552 	attr_nwords = DIV_ROUND_UP(attr_nbits, 32);
553 	if (nla_len(tb[ETHTOOL_A_BITSET_VALUE]) != attr_nwords * sizeof(u32)) {
554 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],
555 				    "bitset value length does not match size");
556 		return -EINVAL;
557 	}
558 	if (tb[ETHTOOL_A_BITSET_MASK] &&
559 	    nla_len(tb[ETHTOOL_A_BITSET_MASK]) != attr_nwords * sizeof(u32)) {
560 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
561 				    "bitset mask length does not match size");
562 		return -EINVAL;
563 	}
564 	if (attr_nbits <= nbits)
565 		return 0;
566 
567 	test_attr = no_mask ? tb[ETHTOOL_A_BITSET_VALUE] :
568 			      tb[ETHTOOL_A_BITSET_MASK];
569 	if (ethnl_bitmap32_not_zero(nla_data(test_attr), nbits, attr_nbits)) {
570 		NL_SET_ERR_MSG_ATTR(extack, test_attr,
571 				    "cannot modify bits past kernel bitset size");
572 		return -EINVAL;
573 	}
574 	return 0;
575 }
576 
577 /**
578  * ethnl_update_bitset32() - Apply a bitset nest to a u32 based bitmap
579  * @bitmap:  bitmap to update
580  * @nbits:   size of the updated bitmap in bits
581  * @attr:    nest attribute to parse and apply
582  * @names:   array of bit names; may be null for compact format
583  * @extack:  extack for error reporting
584  * @mod:     set this to true if bitmap is modified, leave as it is if not
585  *
586  * Apply bitset netsted attribute to a bitmap. If the attribute represents
587  * a bit list, @bitmap is set to its contents; otherwise, bits in mask are
588  * set to values from value. Bitmaps in the attribute may be longer than
589  * @nbits but the message must not request modifying any bits past @nbits.
590  *
591  * Return: negative error code on failure, 0 on success
592  */
593 int ethnl_update_bitset32(u32 *bitmap, unsigned int nbits,
594 			  const struct nlattr *attr, ethnl_string_array_t names,
595 			  struct netlink_ext_ack *extack, bool *mod)
596 {
597 	struct nlattr *tb[ARRAY_SIZE(bitset_policy)];
598 	unsigned int change_bits;
599 	bool no_mask;
600 	int ret;
601 
602 	if (!attr)
603 		return 0;
604 	ret = nla_parse_nested(tb, ARRAY_SIZE(bitset_policy) - 1, attr,
605 			       bitset_policy, extack);
606 	if (ret < 0)
607 		return ret;
608 
609 	if (tb[ETHTOOL_A_BITSET_BITS])
610 		return ethnl_update_bitset32_verbose(bitmap, nbits, attr, tb,
611 						     names, extack, mod);
612 	ret = ethnl_compact_sanity_checks(nbits, attr, tb, extack);
613 	if (ret < 0)
614 		return ret;
615 
616 	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
617 	change_bits = min_t(unsigned int,
618 			    nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]), nbits);
619 	ethnl_bitmap32_update(bitmap, change_bits,
620 			      nla_data(tb[ETHTOOL_A_BITSET_VALUE]),
621 			      no_mask ? NULL :
622 					nla_data(tb[ETHTOOL_A_BITSET_MASK]),
623 			      mod);
624 	if (no_mask && change_bits < nbits)
625 		ethnl_bitmap32_clear(bitmap, change_bits, nbits, mod);
626 
627 	return 0;
628 }
629 
630 /**
631  * ethnl_parse_bitset() - Compute effective value and mask from bitset nest
632  * @val:     unsigned long based bitmap to put value into
633  * @mask:    unsigned long based bitmap to put mask into
634  * @nbits:   size of @val and @mask bitmaps
635  * @attr:    nest attribute to parse and apply
636  * @names:   array of bit names; may be null for compact format
637  * @extack:  extack for error reporting
638  *
639  * Provide @nbits size long bitmaps for value and mask so that
640  * x = (val & mask) | (x & ~mask) would modify any @nbits sized bitmap x
641  * the same way ethnl_update_bitset() with the same bitset attribute would.
642  *
643  * Return:   negative error code on failure, 0 on success
644  */
645 int ethnl_parse_bitset(unsigned long *val, unsigned long *mask,
646 		       unsigned int nbits, const struct nlattr *attr,
647 		       ethnl_string_array_t names,
648 		       struct netlink_ext_ack *extack)
649 {
650 	struct nlattr *tb[ARRAY_SIZE(bitset_policy)];
651 	const struct nlattr *bit_attr;
652 	bool no_mask;
653 	int rem;
654 	int ret;
655 
656 	if (!attr)
657 		return 0;
658 	ret = nla_parse_nested(tb, ARRAY_SIZE(bitset_policy) - 1, attr,
659 			       bitset_policy, extack);
660 	if (ret < 0)
661 		return ret;
662 	no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
663 
664 	if (!tb[ETHTOOL_A_BITSET_BITS]) {
665 		unsigned int change_bits;
666 
667 		ret = ethnl_compact_sanity_checks(nbits, attr, tb, extack);
668 		if (ret < 0)
669 			return ret;
670 
671 		change_bits = nla_get_u32(tb[ETHTOOL_A_BITSET_SIZE]);
672 		if (change_bits > nbits)
673 			change_bits = nbits;
674 		bitmap_from_arr32(val, nla_data(tb[ETHTOOL_A_BITSET_VALUE]),
675 				  change_bits);
676 		if (change_bits < nbits)
677 			bitmap_clear(val, change_bits, nbits - change_bits);
678 		if (no_mask) {
679 			bitmap_fill(mask, nbits);
680 		} else {
681 			bitmap_from_arr32(mask,
682 					  nla_data(tb[ETHTOOL_A_BITSET_MASK]),
683 					  change_bits);
684 			if (change_bits < nbits)
685 				bitmap_clear(mask, change_bits,
686 					     nbits - change_bits);
687 		}
688 
689 		return 0;
690 	}
691 
692 	if (tb[ETHTOOL_A_BITSET_VALUE]) {
693 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_VALUE],
694 				    "value only allowed in compact bitset");
695 		return -EINVAL;
696 	}
697 	if (tb[ETHTOOL_A_BITSET_MASK]) {
698 		NL_SET_ERR_MSG_ATTR(extack, tb[ETHTOOL_A_BITSET_MASK],
699 				    "mask only allowed in compact bitset");
700 		return -EINVAL;
701 	}
702 
703 	bitmap_zero(val, nbits);
704 	if (no_mask)
705 		bitmap_fill(mask, nbits);
706 	else
707 		bitmap_zero(mask, nbits);
708 
709 	nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) {
710 		unsigned int idx;
711 		bool bit_val;
712 
713 		ret = ethnl_parse_bit(&idx, &bit_val, nbits, bit_attr, no_mask,
714 				      names, extack);
715 		if (ret < 0)
716 			return ret;
717 		if (bit_val)
718 			__set_bit(idx, val);
719 		if (!no_mask)
720 			__set_bit(idx, mask);
721 	}
722 
723 	return 0;
724 }
725 
726 #if BITS_PER_LONG == 64 && defined(__BIG_ENDIAN)
727 
728 /* 64-bit big endian architectures are the only case when u32 based bitmaps
729  * and unsigned long based bitmaps have different memory layout so that we
730  * cannot simply cast the latter to the former and need actual wrappers
731  * converting the latter to the former.
732  *
733  * To reduce the number of slab allocations, the wrappers use fixed size local
734  * variables for bitmaps up to ETHNL_SMALL_BITMAP_BITS bits which is the
735  * majority of bitmaps used by ethtool.
736  */
737 #define ETHNL_SMALL_BITMAP_BITS 128
738 #define ETHNL_SMALL_BITMAP_WORDS DIV_ROUND_UP(ETHNL_SMALL_BITMAP_BITS, 32)
739 
740 int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
741 		      unsigned int nbits, ethnl_string_array_t names,
742 		      bool compact)
743 {
744 	u32 small_mask32[ETHNL_SMALL_BITMAP_WORDS];
745 	u32 small_val32[ETHNL_SMALL_BITMAP_WORDS];
746 	u32 *mask32;
747 	u32 *val32;
748 	int ret;
749 
750 	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
751 		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
752 
753 		val32 = kmalloc_array(2 * nwords, sizeof(u32), GFP_KERNEL);
754 		if (!val32)
755 			return -ENOMEM;
756 		mask32 = val32 + nwords;
757 	} else {
758 		val32 = small_val32;
759 		mask32 = small_mask32;
760 	}
761 
762 	bitmap_to_arr32(val32, val, nbits);
763 	if (mask)
764 		bitmap_to_arr32(mask32, mask, nbits);
765 	else
766 		mask32 = NULL;
767 	ret = ethnl_bitset32_size(val32, mask32, nbits, names, compact);
768 
769 	if (nbits > ETHNL_SMALL_BITMAP_BITS)
770 		kfree(val32);
771 
772 	return ret;
773 }
774 
775 int ethnl_put_bitset(struct sk_buff *skb, int attrtype,
776 		     const unsigned long *val, const unsigned long *mask,
777 		     unsigned int nbits, ethnl_string_array_t names,
778 		     bool compact)
779 {
780 	u32 small_mask32[ETHNL_SMALL_BITMAP_WORDS];
781 	u32 small_val32[ETHNL_SMALL_BITMAP_WORDS];
782 	u32 *mask32;
783 	u32 *val32;
784 	int ret;
785 
786 	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
787 		unsigned int nwords = DIV_ROUND_UP(nbits, 32);
788 
789 		val32 = kmalloc_array(2 * nwords, sizeof(u32), GFP_KERNEL);
790 		if (!val32)
791 			return -ENOMEM;
792 		mask32 = val32 + nwords;
793 	} else {
794 		val32 = small_val32;
795 		mask32 = small_mask32;
796 	}
797 
798 	bitmap_to_arr32(val32, val, nbits);
799 	if (mask)
800 		bitmap_to_arr32(mask32, mask, nbits);
801 	else
802 		mask32 = NULL;
803 	ret = ethnl_put_bitset32(skb, attrtype, val32, mask32, nbits, names,
804 				 compact);
805 
806 	if (nbits > ETHNL_SMALL_BITMAP_BITS)
807 		kfree(val32);
808 
809 	return ret;
810 }
811 
812 int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits,
813 			const struct nlattr *attr, ethnl_string_array_t names,
814 			struct netlink_ext_ack *extack, bool *mod)
815 {
816 	u32 small_bitmap32[ETHNL_SMALL_BITMAP_WORDS];
817 	u32 *bitmap32 = small_bitmap32;
818 	bool u32_mod = false;
819 	int ret;
820 
821 	if (nbits > ETHNL_SMALL_BITMAP_BITS) {
822 		unsigned int dst_words = DIV_ROUND_UP(nbits, 32);
823 
824 		bitmap32 = kmalloc_array(dst_words, sizeof(u32), GFP_KERNEL);
825 		if (!bitmap32)
826 			return -ENOMEM;
827 	}
828 
829 	bitmap_to_arr32(bitmap32, bitmap, nbits);
830 	ret = ethnl_update_bitset32(bitmap32, nbits, attr, names, extack,
831 				    &u32_mod);
832 	if (u32_mod) {
833 		bitmap_from_arr32(bitmap, bitmap32, nbits);
834 		*mod = true;
835 	}
836 
837 	if (nbits > ETHNL_SMALL_BITMAP_BITS)
838 		kfree(bitmap32);
839 
840 	return ret;
841 }
842 
843 #else
844 
845 /* On little endian 64-bit and all 32-bit architectures, an unsigned long
846  * based bitmap can be interpreted as u32 based one using a simple cast.
847  */
848 
849 int ethnl_bitset_size(const unsigned long *val, const unsigned long *mask,
850 		      unsigned int nbits, ethnl_string_array_t names,
851 		      bool compact)
852 {
853 	return ethnl_bitset32_size((const u32 *)val, (const u32 *)mask, nbits,
854 				   names, compact);
855 }
856 
857 int ethnl_put_bitset(struct sk_buff *skb, int attrtype,
858 		     const unsigned long *val, const unsigned long *mask,
859 		     unsigned int nbits, ethnl_string_array_t names,
860 		     bool compact)
861 {
862 	return ethnl_put_bitset32(skb, attrtype, (const u32 *)val,
863 				  (const u32 *)mask, nbits, names, compact);
864 }
865 
866 int ethnl_update_bitset(unsigned long *bitmap, unsigned int nbits,
867 			const struct nlattr *attr, ethnl_string_array_t names,
868 			struct netlink_ext_ack *extack, bool *mod)
869 {
870 	return ethnl_update_bitset32((u32 *)bitmap, nbits, attr, names, extack,
871 				     mod);
872 }
873 
874 #endif /* BITS_PER_LONG == 64 && defined(__BIG_ENDIAN) */
875