1/*
  2 * NETLINK      Netlink attributes
  3 *
  4 * 		Authors:	Thomas Graf <tgraf@suug.ch>
  5 * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  6 */
  7
  8#include <linux/export.h>
  9#include <linux/kernel.h>
 10#include <linux/errno.h>
 11#include <linux/jiffies.h>
 12#include <linux/netdevice.h>
 13#include <linux/skbuff.h>
 14#include <linux/string.h>
 15#include <linux/types.h>
 16#include <net/netlink.h>
 17
 18static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
 19	[NLA_U8]	= sizeof(u8),
 20	[NLA_U16]	= sizeof(u16),
 21	[NLA_U32]	= sizeof(u32),
 22	[NLA_U64]	= sizeof(u64),
 23	[NLA_MSECS]	= sizeof(u64),
 24	[NLA_NESTED]	= NLA_HDRLEN,
 25	[NLA_S8]	= sizeof(s8),
 26	[NLA_S16]	= sizeof(s16),
 27	[NLA_S32]	= sizeof(s32),
 28	[NLA_S64]	= sizeof(s64),
 29};
 30
 31static int validate_nla(const struct nlattr *nla, int maxtype,
 32			const struct nla_policy *policy)
 33{
 34	const struct nla_policy *pt;
 35	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
 36
 37	if (type <= 0 || type > maxtype)
 38		return 0;
 39
 40	pt = &policy[type];
 41
 42	BUG_ON(pt->type > NLA_TYPE_MAX);
 43
 44	switch (pt->type) {
 45	case NLA_FLAG:
 46		if (attrlen > 0)
 47			return -ERANGE;
 48		break;
 49
 50	case NLA_NUL_STRING:
 51		if (pt->len)
 52			minlen = min_t(int, attrlen, pt->len + 1);
 53		else
 54			minlen = attrlen;
 55
 56		if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
 57			return -EINVAL;
 58		/* fall through */
 59
 60	case NLA_STRING:
 61		if (attrlen < 1)
 62			return -ERANGE;
 63
 64		if (pt->len) {
 65			char *buf = nla_data(nla);
 66
 67			if (buf[attrlen - 1] == '\0')
 68				attrlen--;
 69
 70			if (attrlen > pt->len)
 71				return -ERANGE;
 72		}
 73		break;
 74
 75	case NLA_BINARY:
 76		if (pt->len && attrlen > pt->len)
 77			return -ERANGE;
 78		break;
 79
 80	case NLA_NESTED_COMPAT:
 81		if (attrlen < pt->len)
 82			return -ERANGE;
 83		if (attrlen < NLA_ALIGN(pt->len))
 84			break;
 85		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
 86			return -ERANGE;
 87		nla = nla_data(nla) + NLA_ALIGN(pt->len);
 88		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
 89			return -ERANGE;
 90		break;
 91	case NLA_NESTED:
 92		/* a nested attributes is allowed to be empty; if its not,
 93		 * it must have a size of at least NLA_HDRLEN.
 94		 */
 95		if (attrlen == 0)
 96			break;
 97	default:
 98		if (pt->len)
 99			minlen = pt->len;
100		else if (pt->type != NLA_UNSPEC)
101			minlen = nla_attr_minlen[pt->type];
102
103		if (attrlen < minlen)
104			return -ERANGE;
105	}
106
107	return 0;
108}
109
110/**
111 * nla_validate - Validate a stream of attributes
112 * @head: head of attribute stream
113 * @len: length of attribute stream
114 * @maxtype: maximum attribute type to be expected
115 * @policy: validation policy
116 *
117 * Validates all attributes in the specified attribute stream against the
118 * specified policy. Attributes with a type exceeding maxtype will be
119 * ignored. See documenation of struct nla_policy for more details.
120 *
121 * Returns 0 on success or a negative error code.
122 */
123int nla_validate(const struct nlattr *head, int len, int maxtype,
124		 const struct nla_policy *policy)
125{
126	const struct nlattr *nla;
127	int rem, err;
128
129	nla_for_each_attr(nla, head, len, rem) {
130		err = validate_nla(nla, maxtype, policy);
131		if (err < 0)
132			goto errout;
133	}
134
135	err = 0;
136errout:
137	return err;
138}
139
140/**
141 * nla_policy_len - Determin the max. length of a policy
142 * @policy: policy to use
143 * @n: number of policies
144 *
145 * Determines the max. length of the policy.  It is currently used
146 * to allocated Netlink buffers roughly the size of the actual
147 * message.
148 *
149 * Returns 0 on success or a negative error code.
150 */
151int
152nla_policy_len(const struct nla_policy *p, int n)
153{
154	int i, len = 0;
155
156	for (i = 0; i < n; i++, p++) {
157		if (p->len)
158			len += nla_total_size(p->len);
159		else if (nla_attr_minlen[p->type])
160			len += nla_total_size(nla_attr_minlen[p->type]);
161	}
162
163	return len;
164}
165
166/**
167 * nla_parse - Parse a stream of attributes into a tb buffer
168 * @tb: destination array with maxtype+1 elements
169 * @maxtype: maximum attribute type to be expected
170 * @head: head of attribute stream
171 * @len: length of attribute stream
172 * @policy: validation policy
173 *
174 * Parses a stream of attributes and stores a pointer to each attribute in
175 * the tb array accessible via the attribute type. Attributes with a type
176 * exceeding maxtype will be silently ignored for backwards compatibility
177 * reasons. policy may be set to NULL if no validation is required.
178 *
179 * Returns 0 on success or a negative error code.
180 */
181int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
182	      int len, const struct nla_policy *policy)
183{
184	const struct nlattr *nla;
185	int rem, err;
186
187	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
188
189	nla_for_each_attr(nla, head, len, rem) {
190		u16 type = nla_type(nla);
191
192		if (type > 0 && type <= maxtype) {
193			if (policy) {
194				err = validate_nla(nla, maxtype, policy);
195				if (err < 0)
196					goto errout;
197			}
198
199			tb[type] = (struct nlattr *)nla;
200		}
201	}
202
203	if (unlikely(rem > 0))
204		pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
205				    rem, current->comm);
206
207	err = 0;
208errout:
209	return err;
210}
211
212/**
213 * nla_find - Find a specific attribute in a stream of attributes
214 * @head: head of attribute stream
215 * @len: length of attribute stream
216 * @attrtype: type of attribute to look for
217 *
218 * Returns the first attribute in the stream matching the specified type.
219 */
220struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
221{
222	const struct nlattr *nla;
223	int rem;
224
225	nla_for_each_attr(nla, head, len, rem)
226		if (nla_type(nla) == attrtype)
227			return (struct nlattr *)nla;
228
229	return NULL;
230}
231
232/**
233 * nla_strlcpy - Copy string attribute payload into a sized buffer
234 * @dst: where to copy the string to
235 * @nla: attribute to copy the string from
236 * @dstsize: size of destination buffer
237 *
238 * Copies at most dstsize - 1 bytes into the destination buffer.
239 * The result is always a valid NUL-terminated string. Unlike
240 * strlcpy the destination buffer is always padded out.
241 *
242 * Returns the length of the source buffer.
243 */
244size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
245{
246	size_t srclen = nla_len(nla);
247	char *src = nla_data(nla);
248
249	if (srclen > 0 && src[srclen - 1] == '\0')
250		srclen--;
251
252	if (dstsize > 0) {
253		size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
254
255		memset(dst, 0, dstsize);
256		memcpy(dst, src, len);
257	}
258
259	return srclen;
260}
261
262/**
263 * nla_memcpy - Copy a netlink attribute into another memory area
264 * @dest: where to copy to memcpy
265 * @src: netlink attribute to copy from
266 * @count: size of the destination area
267 *
268 * Note: The number of bytes copied is limited by the length of
269 *       attribute's payload. memcpy
270 *
271 * Returns the number of bytes copied.
272 */
273int nla_memcpy(void *dest, const struct nlattr *src, int count)
274{
275	int minlen = min_t(int, count, nla_len(src));
276
277	memcpy(dest, nla_data(src), minlen);
278
279	return minlen;
280}
281
282/**
283 * nla_memcmp - Compare an attribute with sized memory area
284 * @nla: netlink attribute
285 * @data: memory area
286 * @size: size of memory area
287 */
288int nla_memcmp(const struct nlattr *nla, const void *data,
289			     size_t size)
290{
291	int d = nla_len(nla) - size;
292
293	if (d == 0)
294		d = memcmp(nla_data(nla), data, size);
295
296	return d;
297}
298
299/**
300 * nla_strcmp - Compare a string attribute against a string
301 * @nla: netlink string attribute
302 * @str: another string
303 */
304int nla_strcmp(const struct nlattr *nla, const char *str)
305{
306	int len = strlen(str);
307	char *buf = nla_data(nla);
308	int attrlen = nla_len(nla);
309	int d;
310
311	if (attrlen > 0 && buf[attrlen - 1] == '\0')
312		attrlen--;
313
314	d = attrlen - len;
315	if (d == 0)
316		d = memcmp(nla_data(nla), str, len);
317
318	return d;
319}
320
321#ifdef CONFIG_NET
322/**
323 * __nla_reserve - reserve room for attribute on the skb
324 * @skb: socket buffer to reserve room on
325 * @attrtype: attribute type
326 * @attrlen: length of attribute payload
327 *
328 * Adds a netlink attribute header to a socket buffer and reserves
329 * room for the payload but does not copy it.
330 *
331 * The caller is responsible to ensure that the skb provides enough
332 * tailroom for the attribute header and payload.
333 */
334struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
335{
336	struct nlattr *nla;
337
338	nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
339	nla->nla_type = attrtype;
340	nla->nla_len = nla_attr_size(attrlen);
341
342	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
343
344	return nla;
345}
346EXPORT_SYMBOL(__nla_reserve);
347
348/**
349 * __nla_reserve_nohdr - reserve room for attribute without header
350 * @skb: socket buffer to reserve room on
351 * @attrlen: length of attribute payload
352 *
353 * Reserves room for attribute payload without a header.
354 *
355 * The caller is responsible to ensure that the skb provides enough
356 * tailroom for the payload.
357 */
358void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
359{
360	void *start;
361
362	start = skb_put(skb, NLA_ALIGN(attrlen));
363	memset(start, 0, NLA_ALIGN(attrlen));
364
365	return start;
366}
367EXPORT_SYMBOL(__nla_reserve_nohdr);
368
369/**
370 * nla_reserve - reserve room for attribute on the skb
371 * @skb: socket buffer to reserve room on
372 * @attrtype: attribute type
373 * @attrlen: length of attribute payload
374 *
375 * Adds a netlink attribute header to a socket buffer and reserves
376 * room for the payload but does not copy it.
377 *
378 * Returns NULL if the tailroom of the skb is insufficient to store
379 * the attribute header and payload.
380 */
381struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
382{
383	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
384		return NULL;
385
386	return __nla_reserve(skb, attrtype, attrlen);
387}
388EXPORT_SYMBOL(nla_reserve);
389
390/**
391 * nla_reserve_nohdr - reserve room for attribute without header
392 * @skb: socket buffer to reserve room on
393 * @attrlen: length of attribute payload
394 *
395 * Reserves room for attribute payload without a header.
396 *
397 * Returns NULL if the tailroom of the skb is insufficient to store
398 * the attribute payload.
399 */
400void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
401{
402	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
403		return NULL;
404
405	return __nla_reserve_nohdr(skb, attrlen);
406}
407EXPORT_SYMBOL(nla_reserve_nohdr);
408
409/**
410 * __nla_put - Add a netlink attribute to a socket buffer
411 * @skb: socket buffer to add attribute to
412 * @attrtype: attribute type
413 * @attrlen: length of attribute payload
414 * @data: head of attribute payload
415 *
416 * The caller is responsible to ensure that the skb provides enough
417 * tailroom for the attribute header and payload.
418 */
419void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
420			     const void *data)
421{
422	struct nlattr *nla;
423
424	nla = __nla_reserve(skb, attrtype, attrlen);
425	memcpy(nla_data(nla), data, attrlen);
426}
427EXPORT_SYMBOL(__nla_put);
428
429/**
430 * __nla_put_nohdr - Add a netlink attribute without header
431 * @skb: socket buffer to add attribute to
432 * @attrlen: length of attribute payload
433 * @data: head of attribute payload
434 *
435 * The caller is responsible to ensure that the skb provides enough
436 * tailroom for the attribute payload.
437 */
438void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
439{
440	void *start;
441
442	start = __nla_reserve_nohdr(skb, attrlen);
443	memcpy(start, data, attrlen);
444}
445EXPORT_SYMBOL(__nla_put_nohdr);
446
447/**
448 * nla_put - Add a netlink attribute to a socket buffer
449 * @skb: socket buffer to add attribute to
450 * @attrtype: attribute type
451 * @attrlen: length of attribute payload
452 * @data: head of attribute payload
453 *
454 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
455 * the attribute header and payload.
456 */
457int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
458{
459	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
460		return -EMSGSIZE;
461
462	__nla_put(skb, attrtype, attrlen, data);
463	return 0;
464}
465EXPORT_SYMBOL(nla_put);
466
467/**
468 * nla_put_nohdr - Add a netlink attribute without header
469 * @skb: socket buffer to add attribute to
470 * @attrlen: length of attribute payload
471 * @data: head of attribute payload
472 *
473 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
474 * the attribute payload.
475 */
476int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
477{
478	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
479		return -EMSGSIZE;
480
481	__nla_put_nohdr(skb, attrlen, data);
482	return 0;
483}
484EXPORT_SYMBOL(nla_put_nohdr);
485
486/**
487 * nla_append - Add a netlink attribute without header or padding
488 * @skb: socket buffer to add attribute to
489 * @attrlen: length of attribute payload
490 * @data: head of attribute payload
491 *
492 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
493 * the attribute payload.
494 */
495int nla_append(struct sk_buff *skb, int attrlen, const void *data)
496{
497	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
498		return -EMSGSIZE;
499
500	memcpy(skb_put(skb, attrlen), data, attrlen);
501	return 0;
502}
503EXPORT_SYMBOL(nla_append);
504#endif
505
506EXPORT_SYMBOL(nla_validate);
507EXPORT_SYMBOL(nla_policy_len);
508EXPORT_SYMBOL(nla_parse);
509EXPORT_SYMBOL(nla_find);
510EXPORT_SYMBOL(nla_strlcpy);
511EXPORT_SYMBOL(nla_memcpy);
512EXPORT_SYMBOL(nla_memcmp);
513EXPORT_SYMBOL(nla_strcmp);

  1/*
  2 * NETLINK      Netlink attributes
  3 *
  4 * 		Authors:	Thomas Graf <tgraf@suug.ch>
  5 * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/kernel.h>
 10#include <linux/errno.h>
 11#include <linux/jiffies.h>
 12#include <linux/netdevice.h>
 13#include <linux/skbuff.h>
 14#include <linux/string.h>
 15#include <linux/types.h>
 16#include <net/netlink.h>
 17
 18static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
 19	[NLA_U8]	= sizeof(u8),
 20	[NLA_U16]	= sizeof(u16),
 21	[NLA_U32]	= sizeof(u32),
 22	[NLA_U64]	= sizeof(u64),
 
 23	[NLA_NESTED]	= NLA_HDRLEN,
 
 
 
 
 24};
 25
 26static int validate_nla(const struct nlattr *nla, int maxtype,
 27			const struct nla_policy *policy)
 28{
 29	const struct nla_policy *pt;
 30	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
 31
 32	if (type <= 0 || type > maxtype)
 33		return 0;
 34
 35	pt = &policy[type];
 36
 37	BUG_ON(pt->type > NLA_TYPE_MAX);
 38
 39	switch (pt->type) {
 40	case NLA_FLAG:
 41		if (attrlen > 0)
 42			return -ERANGE;
 43		break;
 44
 45	case NLA_NUL_STRING:
 46		if (pt->len)
 47			minlen = min_t(int, attrlen, pt->len + 1);
 48		else
 49			minlen = attrlen;
 50
 51		if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
 52			return -EINVAL;
 53		/* fall through */
 54
 55	case NLA_STRING:
 56		if (attrlen < 1)
 57			return -ERANGE;
 58
 59		if (pt->len) {
 60			char *buf = nla_data(nla);
 61
 62			if (buf[attrlen - 1] == '\0')
 63				attrlen--;
 64
 65			if (attrlen > pt->len)
 66				return -ERANGE;
 67		}
 68		break;
 69
 70	case NLA_BINARY:
 71		if (pt->len && attrlen > pt->len)
 72			return -ERANGE;
 73		break;
 74
 75	case NLA_NESTED_COMPAT:
 76		if (attrlen < pt->len)
 77			return -ERANGE;
 78		if (attrlen < NLA_ALIGN(pt->len))
 79			break;
 80		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
 81			return -ERANGE;
 82		nla = nla_data(nla) + NLA_ALIGN(pt->len);
 83		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
 84			return -ERANGE;
 85		break;
 86	case NLA_NESTED:
 87		/* a nested attributes is allowed to be empty; if its not,
 88		 * it must have a size of at least NLA_HDRLEN.
 89		 */
 90		if (attrlen == 0)
 91			break;
 92	default:
 93		if (pt->len)
 94			minlen = pt->len;
 95		else if (pt->type != NLA_UNSPEC)
 96			minlen = nla_attr_minlen[pt->type];
 97
 98		if (attrlen < minlen)
 99			return -ERANGE;
100	}
101
102	return 0;
103}
104
105/**
106 * nla_validate - Validate a stream of attributes
107 * @head: head of attribute stream
108 * @len: length of attribute stream
109 * @maxtype: maximum attribute type to be expected
110 * @policy: validation policy
111 *
112 * Validates all attributes in the specified attribute stream against the
113 * specified policy. Attributes with a type exceeding maxtype will be
114 * ignored. See documenation of struct nla_policy for more details.
115 *
116 * Returns 0 on success or a negative error code.
117 */
118int nla_validate(const struct nlattr *head, int len, int maxtype,
119		 const struct nla_policy *policy)
120{
121	const struct nlattr *nla;
122	int rem, err;
123
124	nla_for_each_attr(nla, head, len, rem) {
125		err = validate_nla(nla, maxtype, policy);
126		if (err < 0)
127			goto errout;
128	}
129
130	err = 0;
131errout:
132	return err;
133}
134
135/**
136 * nla_policy_len - Determin the max. length of a policy
137 * @policy: policy to use
138 * @n: number of policies
139 *
140 * Determines the max. length of the policy.  It is currently used
141 * to allocated Netlink buffers roughly the size of the actual
142 * message.
143 *
144 * Returns 0 on success or a negative error code.
145 */
146int
147nla_policy_len(const struct nla_policy *p, int n)
148{
149	int i, len = 0;
150
151	for (i = 0; i < n; i++, p++) {
152		if (p->len)
153			len += nla_total_size(p->len);
154		else if (nla_attr_minlen[p->type])
155			len += nla_total_size(nla_attr_minlen[p->type]);
156	}
157
158	return len;
159}
160
161/**
162 * nla_parse - Parse a stream of attributes into a tb buffer
163 * @tb: destination array with maxtype+1 elements
164 * @maxtype: maximum attribute type to be expected
165 * @head: head of attribute stream
166 * @len: length of attribute stream
167 * @policy: validation policy
168 *
169 * Parses a stream of attributes and stores a pointer to each attribute in
170 * the tb array accessible via the attribute type. Attributes with a type
171 * exceeding maxtype will be silently ignored for backwards compatibility
172 * reasons. policy may be set to NULL if no validation is required.
173 *
174 * Returns 0 on success or a negative error code.
175 */
176int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
177	      int len, const struct nla_policy *policy)
178{
179	const struct nlattr *nla;
180	int rem, err;
181
182	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
183
184	nla_for_each_attr(nla, head, len, rem) {
185		u16 type = nla_type(nla);
186
187		if (type > 0 && type <= maxtype) {
188			if (policy) {
189				err = validate_nla(nla, maxtype, policy);
190				if (err < 0)
191					goto errout;
192			}
193
194			tb[type] = (struct nlattr *)nla;
195		}
196	}
197
198	if (unlikely(rem > 0))
199		printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
200		       "attributes.\n", rem);
201
202	err = 0;
203errout:
204	return err;
205}
206
207/**
208 * nla_find - Find a specific attribute in a stream of attributes
209 * @head: head of attribute stream
210 * @len: length of attribute stream
211 * @attrtype: type of attribute to look for
212 *
213 * Returns the first attribute in the stream matching the specified type.
214 */
215struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
216{
217	const struct nlattr *nla;
218	int rem;
219
220	nla_for_each_attr(nla, head, len, rem)
221		if (nla_type(nla) == attrtype)
222			return (struct nlattr *)nla;
223
224	return NULL;
225}
226
227/**
228 * nla_strlcpy - Copy string attribute payload into a sized buffer
229 * @dst: where to copy the string to
230 * @nla: attribute to copy the string from
231 * @dstsize: size of destination buffer
232 *
233 * Copies at most dstsize - 1 bytes into the destination buffer.
234 * The result is always a valid NUL-terminated string. Unlike
235 * strlcpy the destination buffer is always padded out.
236 *
237 * Returns the length of the source buffer.
238 */
239size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
240{
241	size_t srclen = nla_len(nla);
242	char *src = nla_data(nla);
243
244	if (srclen > 0 && src[srclen - 1] == '\0')
245		srclen--;
246
247	if (dstsize > 0) {
248		size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
249
250		memset(dst, 0, dstsize);
251		memcpy(dst, src, len);
252	}
253
254	return srclen;
255}
256
257/**
258 * nla_memcpy - Copy a netlink attribute into another memory area
259 * @dest: where to copy to memcpy
260 * @src: netlink attribute to copy from
261 * @count: size of the destination area
262 *
263 * Note: The number of bytes copied is limited by the length of
264 *       attribute's payload. memcpy
265 *
266 * Returns the number of bytes copied.
267 */
268int nla_memcpy(void *dest, const struct nlattr *src, int count)
269{
270	int minlen = min_t(int, count, nla_len(src));
271
272	memcpy(dest, nla_data(src), minlen);
273
274	return minlen;
275}
276
277/**
278 * nla_memcmp - Compare an attribute with sized memory area
279 * @nla: netlink attribute
280 * @data: memory area
281 * @size: size of memory area
282 */
283int nla_memcmp(const struct nlattr *nla, const void *data,
284			     size_t size)
285{
286	int d = nla_len(nla) - size;
287
288	if (d == 0)
289		d = memcmp(nla_data(nla), data, size);
290
291	return d;
292}
293
294/**
295 * nla_strcmp - Compare a string attribute against a string
296 * @nla: netlink string attribute
297 * @str: another string
298 */
299int nla_strcmp(const struct nlattr *nla, const char *str)
300{
301	int len = strlen(str) + 1;
302	int d = nla_len(nla) - len;
 
 
303
 
 
 
 
304	if (d == 0)
305		d = memcmp(nla_data(nla), str, len);
306
307	return d;
308}
309
310#ifdef CONFIG_NET
311/**
312 * __nla_reserve - reserve room for attribute on the skb
313 * @skb: socket buffer to reserve room on
314 * @attrtype: attribute type
315 * @attrlen: length of attribute payload
316 *
317 * Adds a netlink attribute header to a socket buffer and reserves
318 * room for the payload but does not copy it.
319 *
320 * The caller is responsible to ensure that the skb provides enough
321 * tailroom for the attribute header and payload.
322 */
323struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
324{
325	struct nlattr *nla;
326
327	nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
328	nla->nla_type = attrtype;
329	nla->nla_len = nla_attr_size(attrlen);
330
331	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
332
333	return nla;
334}
335EXPORT_SYMBOL(__nla_reserve);
336
337/**
338 * __nla_reserve_nohdr - reserve room for attribute without header
339 * @skb: socket buffer to reserve room on
340 * @attrlen: length of attribute payload
341 *
342 * Reserves room for attribute payload without a header.
343 *
344 * The caller is responsible to ensure that the skb provides enough
345 * tailroom for the payload.
346 */
347void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
348{
349	void *start;
350
351	start = skb_put(skb, NLA_ALIGN(attrlen));
352	memset(start, 0, NLA_ALIGN(attrlen));
353
354	return start;
355}
356EXPORT_SYMBOL(__nla_reserve_nohdr);
357
358/**
359 * nla_reserve - reserve room for attribute on the skb
360 * @skb: socket buffer to reserve room on
361 * @attrtype: attribute type
362 * @attrlen: length of attribute payload
363 *
364 * Adds a netlink attribute header to a socket buffer and reserves
365 * room for the payload but does not copy it.
366 *
367 * Returns NULL if the tailroom of the skb is insufficient to store
368 * the attribute header and payload.
369 */
370struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
371{
372	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
373		return NULL;
374
375	return __nla_reserve(skb, attrtype, attrlen);
376}
377EXPORT_SYMBOL(nla_reserve);
378
379/**
380 * nla_reserve_nohdr - reserve room for attribute without header
381 * @skb: socket buffer to reserve room on
382 * @attrlen: length of attribute payload
383 *
384 * Reserves room for attribute payload without a header.
385 *
386 * Returns NULL if the tailroom of the skb is insufficient to store
387 * the attribute payload.
388 */
389void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
390{
391	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
392		return NULL;
393
394	return __nla_reserve_nohdr(skb, attrlen);
395}
396EXPORT_SYMBOL(nla_reserve_nohdr);
397
398/**
399 * __nla_put - Add a netlink attribute to a socket buffer
400 * @skb: socket buffer to add attribute to
401 * @attrtype: attribute type
402 * @attrlen: length of attribute payload
403 * @data: head of attribute payload
404 *
405 * The caller is responsible to ensure that the skb provides enough
406 * tailroom for the attribute header and payload.
407 */
408void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
409			     const void *data)
410{
411	struct nlattr *nla;
412
413	nla = __nla_reserve(skb, attrtype, attrlen);
414	memcpy(nla_data(nla), data, attrlen);
415}
416EXPORT_SYMBOL(__nla_put);
417
418/**
419 * __nla_put_nohdr - Add a netlink attribute without header
420 * @skb: socket buffer to add attribute to
421 * @attrlen: length of attribute payload
422 * @data: head of attribute payload
423 *
424 * The caller is responsible to ensure that the skb provides enough
425 * tailroom for the attribute payload.
426 */
427void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
428{
429	void *start;
430
431	start = __nla_reserve_nohdr(skb, attrlen);
432	memcpy(start, data, attrlen);
433}
434EXPORT_SYMBOL(__nla_put_nohdr);
435
436/**
437 * nla_put - Add a netlink attribute to a socket buffer
438 * @skb: socket buffer to add attribute to
439 * @attrtype: attribute type
440 * @attrlen: length of attribute payload
441 * @data: head of attribute payload
442 *
443 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
444 * the attribute header and payload.
445 */
446int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
447{
448	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
449		return -EMSGSIZE;
450
451	__nla_put(skb, attrtype, attrlen, data);
452	return 0;
453}
454EXPORT_SYMBOL(nla_put);
455
456/**
457 * nla_put_nohdr - Add a netlink attribute without header
458 * @skb: socket buffer to add attribute to
459 * @attrlen: length of attribute payload
460 * @data: head of attribute payload
461 *
462 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
463 * the attribute payload.
464 */
465int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
466{
467	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
468		return -EMSGSIZE;
469
470	__nla_put_nohdr(skb, attrlen, data);
471	return 0;
472}
473EXPORT_SYMBOL(nla_put_nohdr);
474
475/**
476 * nla_append - Add a netlink attribute without header or padding
477 * @skb: socket buffer to add attribute to
478 * @attrlen: length of attribute payload
479 * @data: head of attribute payload
480 *
481 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
482 * the attribute payload.
483 */
484int nla_append(struct sk_buff *skb, int attrlen, const void *data)
485{
486	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
487		return -EMSGSIZE;
488
489	memcpy(skb_put(skb, attrlen), data, attrlen);
490	return 0;
491}
492EXPORT_SYMBOL(nla_append);
493#endif
494
495EXPORT_SYMBOL(nla_validate);
496EXPORT_SYMBOL(nla_policy_len);
497EXPORT_SYMBOL(nla_parse);
498EXPORT_SYMBOL(nla_find);
499EXPORT_SYMBOL(nla_strlcpy);
500EXPORT_SYMBOL(nla_memcpy);
501EXPORT_SYMBOL(nla_memcmp);
502EXPORT_SYMBOL(nla_strcmp);