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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/export.h>
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/jiffies.h>
12#include <linux/skbuff.h>
13#include <linux/string.h>
14#include <linux/types.h>
15#include <net/netlink.h>
16
17static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
18 [NLA_U8] = sizeof(u8),
19 [NLA_U16] = sizeof(u16),
20 [NLA_U32] = sizeof(u32),
21 [NLA_U64] = sizeof(u64),
22 [NLA_MSECS] = sizeof(u64),
23 [NLA_NESTED] = NLA_HDRLEN,
24 [NLA_S8] = sizeof(s8),
25 [NLA_S16] = sizeof(s16),
26 [NLA_S32] = sizeof(s32),
27 [NLA_S64] = sizeof(s64),
28};
29
30static int validate_nla(const struct nlattr *nla, int maxtype,
31 const struct nla_policy *policy)
32{
33 const struct nla_policy *pt;
34 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
35
36 if (type <= 0 || type > maxtype)
37 return 0;
38
39 pt = &policy[type];
40
41 BUG_ON(pt->type > NLA_TYPE_MAX);
42
43 switch (pt->type) {
44 case NLA_FLAG:
45 if (attrlen > 0)
46 return -ERANGE;
47 break;
48
49 case NLA_NUL_STRING:
50 if (pt->len)
51 minlen = min_t(int, attrlen, pt->len + 1);
52 else
53 minlen = attrlen;
54
55 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
56 return -EINVAL;
57 /* fall through */
58
59 case NLA_STRING:
60 if (attrlen < 1)
61 return -ERANGE;
62
63 if (pt->len) {
64 char *buf = nla_data(nla);
65
66 if (buf[attrlen - 1] == '\0')
67 attrlen--;
68
69 if (attrlen > pt->len)
70 return -ERANGE;
71 }
72 break;
73
74 case NLA_BINARY:
75 if (pt->len && attrlen > pt->len)
76 return -ERANGE;
77 break;
78
79 case NLA_NESTED_COMPAT:
80 if (attrlen < pt->len)
81 return -ERANGE;
82 if (attrlen < NLA_ALIGN(pt->len))
83 break;
84 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
85 return -ERANGE;
86 nla = nla_data(nla) + NLA_ALIGN(pt->len);
87 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
88 return -ERANGE;
89 break;
90 case NLA_NESTED:
91 /* a nested attributes is allowed to be empty; if its not,
92 * it must have a size of at least NLA_HDRLEN.
93 */
94 if (attrlen == 0)
95 break;
96 default:
97 if (pt->len)
98 minlen = pt->len;
99 else if (pt->type != NLA_UNSPEC)
100 minlen = nla_attr_minlen[pt->type];
101
102 if (attrlen < minlen)
103 return -ERANGE;
104 }
105
106 return 0;
107}
108
109/**
110 * nla_validate - Validate a stream of attributes
111 * @head: head of attribute stream
112 * @len: length of attribute stream
113 * @maxtype: maximum attribute type to be expected
114 * @policy: validation policy
115 *
116 * Validates all attributes in the specified attribute stream against the
117 * specified policy. Attributes with a type exceeding maxtype will be
118 * ignored. See documenation of struct nla_policy for more details.
119 *
120 * Returns 0 on success or a negative error code.
121 */
122int nla_validate(const struct nlattr *head, int len, int maxtype,
123 const struct nla_policy *policy)
124{
125 const struct nlattr *nla;
126 int rem, err;
127
128 nla_for_each_attr(nla, head, len, rem) {
129 err = validate_nla(nla, maxtype, policy);
130 if (err < 0)
131 goto errout;
132 }
133
134 err = 0;
135errout:
136 return err;
137}
138EXPORT_SYMBOL(nla_validate);
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}
165EXPORT_SYMBOL(nla_policy_len);
166
167/**
168 * nla_parse - Parse a stream of attributes into a tb buffer
169 * @tb: destination array with maxtype+1 elements
170 * @maxtype: maximum attribute type to be expected
171 * @head: head of attribute stream
172 * @len: length of attribute stream
173 * @policy: validation policy
174 *
175 * Parses a stream of attributes and stores a pointer to each attribute in
176 * the tb array accessible via the attribute type. Attributes with a type
177 * exceeding maxtype will be silently ignored for backwards compatibility
178 * reasons. policy may be set to NULL if no validation is required.
179 *
180 * Returns 0 on success or a negative error code.
181 */
182int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
183 int len, const struct nla_policy *policy)
184{
185 const struct nlattr *nla;
186 int rem, err;
187
188 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
189
190 nla_for_each_attr(nla, head, len, rem) {
191 u16 type = nla_type(nla);
192
193 if (type > 0 && type <= maxtype) {
194 if (policy) {
195 err = validate_nla(nla, maxtype, policy);
196 if (err < 0)
197 goto errout;
198 }
199
200 tb[type] = (struct nlattr *)nla;
201 }
202 }
203
204 if (unlikely(rem > 0))
205 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
206 rem, current->comm);
207
208 err = 0;
209errout:
210 return err;
211}
212EXPORT_SYMBOL(nla_parse);
213
214/**
215 * nla_find - Find a specific attribute in a stream of attributes
216 * @head: head of attribute stream
217 * @len: length of attribute stream
218 * @attrtype: type of attribute to look for
219 *
220 * Returns the first attribute in the stream matching the specified type.
221 */
222struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
223{
224 const struct nlattr *nla;
225 int rem;
226
227 nla_for_each_attr(nla, head, len, rem)
228 if (nla_type(nla) == attrtype)
229 return (struct nlattr *)nla;
230
231 return NULL;
232}
233EXPORT_SYMBOL(nla_find);
234
235/**
236 * nla_strlcpy - Copy string attribute payload into a sized buffer
237 * @dst: where to copy the string to
238 * @nla: attribute to copy the string from
239 * @dstsize: size of destination buffer
240 *
241 * Copies at most dstsize - 1 bytes into the destination buffer.
242 * The result is always a valid NUL-terminated string. Unlike
243 * strlcpy the destination buffer is always padded out.
244 *
245 * Returns the length of the source buffer.
246 */
247size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
248{
249 size_t srclen = nla_len(nla);
250 char *src = nla_data(nla);
251
252 if (srclen > 0 && src[srclen - 1] == '\0')
253 srclen--;
254
255 if (dstsize > 0) {
256 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
257
258 memset(dst, 0, dstsize);
259 memcpy(dst, src, len);
260 }
261
262 return srclen;
263}
264EXPORT_SYMBOL(nla_strlcpy);
265
266/**
267 * nla_memcpy - Copy a netlink attribute into another memory area
268 * @dest: where to copy to memcpy
269 * @src: netlink attribute to copy from
270 * @count: size of the destination area
271 *
272 * Note: The number of bytes copied is limited by the length of
273 * attribute's payload. memcpy
274 *
275 * Returns the number of bytes copied.
276 */
277int nla_memcpy(void *dest, const struct nlattr *src, int count)
278{
279 int minlen = min_t(int, count, nla_len(src));
280
281 memcpy(dest, nla_data(src), minlen);
282 if (count > minlen)
283 memset(dest + minlen, 0, count - minlen);
284
285 return minlen;
286}
287EXPORT_SYMBOL(nla_memcpy);
288
289/**
290 * nla_memcmp - Compare an attribute with sized memory area
291 * @nla: netlink attribute
292 * @data: memory area
293 * @size: size of memory area
294 */
295int nla_memcmp(const struct nlattr *nla, const void *data,
296 size_t size)
297{
298 int d = nla_len(nla) - size;
299
300 if (d == 0)
301 d = memcmp(nla_data(nla), data, size);
302
303 return d;
304}
305EXPORT_SYMBOL(nla_memcmp);
306
307/**
308 * nla_strcmp - Compare a string attribute against a string
309 * @nla: netlink string attribute
310 * @str: another string
311 */
312int nla_strcmp(const struct nlattr *nla, const char *str)
313{
314 int len = strlen(str);
315 char *buf = nla_data(nla);
316 int attrlen = nla_len(nla);
317 int d;
318
319 if (attrlen > 0 && buf[attrlen - 1] == '\0')
320 attrlen--;
321
322 d = attrlen - len;
323 if (d == 0)
324 d = memcmp(nla_data(nla), str, len);
325
326 return d;
327}
328EXPORT_SYMBOL(nla_strcmp);
329
330#ifdef CONFIG_NET
331/**
332 * __nla_reserve - reserve room for attribute on the skb
333 * @skb: socket buffer to reserve room on
334 * @attrtype: attribute type
335 * @attrlen: length of attribute payload
336 *
337 * Adds a netlink attribute header to a socket buffer and reserves
338 * room for the payload but does not copy it.
339 *
340 * The caller is responsible to ensure that the skb provides enough
341 * tailroom for the attribute header and payload.
342 */
343struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
344{
345 struct nlattr *nla;
346
347 nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
348 nla->nla_type = attrtype;
349 nla->nla_len = nla_attr_size(attrlen);
350
351 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
352
353 return nla;
354}
355EXPORT_SYMBOL(__nla_reserve);
356
357/**
358 * __nla_reserve_64bit - reserve room for attribute on the skb and align it
359 * @skb: socket buffer to reserve room on
360 * @attrtype: attribute type
361 * @attrlen: length of attribute payload
362 * @padattr: attribute type for the padding
363 *
364 * Adds a netlink attribute header to a socket buffer and reserves
365 * room for the payload but does not copy it. It also ensure that this
366 * attribute will have a 64-bit aligned nla_data() area.
367 *
368 * The caller is responsible to ensure that the skb provides enough
369 * tailroom for the attribute header and payload.
370 */
371struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
372 int attrlen, int padattr)
373{
374 if (nla_need_padding_for_64bit(skb))
375 nla_align_64bit(skb, padattr);
376
377 return __nla_reserve(skb, attrtype, attrlen);
378}
379EXPORT_SYMBOL(__nla_reserve_64bit);
380
381/**
382 * __nla_reserve_nohdr - reserve room for attribute without header
383 * @skb: socket buffer to reserve room on
384 * @attrlen: length of attribute payload
385 *
386 * Reserves room for attribute payload without a header.
387 *
388 * The caller is responsible to ensure that the skb provides enough
389 * tailroom for the payload.
390 */
391void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
392{
393 void *start;
394
395 start = skb_put(skb, NLA_ALIGN(attrlen));
396 memset(start, 0, NLA_ALIGN(attrlen));
397
398 return start;
399}
400EXPORT_SYMBOL(__nla_reserve_nohdr);
401
402/**
403 * nla_reserve - reserve room for attribute on the skb
404 * @skb: socket buffer to reserve room on
405 * @attrtype: attribute type
406 * @attrlen: length of attribute payload
407 *
408 * Adds a netlink attribute header to a socket buffer and reserves
409 * room for the payload but does not copy it.
410 *
411 * Returns NULL if the tailroom of the skb is insufficient to store
412 * the attribute header and payload.
413 */
414struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
415{
416 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
417 return NULL;
418
419 return __nla_reserve(skb, attrtype, attrlen);
420}
421EXPORT_SYMBOL(nla_reserve);
422
423/**
424 * nla_reserve_64bit - reserve room for attribute on the skb and align it
425 * @skb: socket buffer to reserve room on
426 * @attrtype: attribute type
427 * @attrlen: length of attribute payload
428 * @padattr: attribute type for the padding
429 *
430 * Adds a netlink attribute header to a socket buffer and reserves
431 * room for the payload but does not copy it. It also ensure that this
432 * attribute will have a 64-bit aligned nla_data() area.
433 *
434 * Returns NULL if the tailroom of the skb is insufficient to store
435 * the attribute header and payload.
436 */
437struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
438 int padattr)
439{
440 size_t len;
441
442 if (nla_need_padding_for_64bit(skb))
443 len = nla_total_size_64bit(attrlen);
444 else
445 len = nla_total_size(attrlen);
446 if (unlikely(skb_tailroom(skb) < len))
447 return NULL;
448
449 return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
450}
451EXPORT_SYMBOL(nla_reserve_64bit);
452
453/**
454 * nla_reserve_nohdr - reserve room for attribute without header
455 * @skb: socket buffer to reserve room on
456 * @attrlen: length of attribute payload
457 *
458 * Reserves room for attribute payload without a header.
459 *
460 * Returns NULL if the tailroom of the skb is insufficient to store
461 * the attribute payload.
462 */
463void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
464{
465 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
466 return NULL;
467
468 return __nla_reserve_nohdr(skb, attrlen);
469}
470EXPORT_SYMBOL(nla_reserve_nohdr);
471
472/**
473 * __nla_put - Add a netlink attribute to a socket buffer
474 * @skb: socket buffer to add attribute to
475 * @attrtype: attribute type
476 * @attrlen: length of attribute payload
477 * @data: head of attribute payload
478 *
479 * The caller is responsible to ensure that the skb provides enough
480 * tailroom for the attribute header and payload.
481 */
482void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
483 const void *data)
484{
485 struct nlattr *nla;
486
487 nla = __nla_reserve(skb, attrtype, attrlen);
488 memcpy(nla_data(nla), data, attrlen);
489}
490EXPORT_SYMBOL(__nla_put);
491
492/**
493 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
494 * @skb: socket buffer to add attribute to
495 * @attrtype: attribute type
496 * @attrlen: length of attribute payload
497 * @data: head of attribute payload
498 * @padattr: attribute type for the padding
499 *
500 * The caller is responsible to ensure that the skb provides enough
501 * tailroom for the attribute header and payload.
502 */
503void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
504 const void *data, int padattr)
505{
506 struct nlattr *nla;
507
508 nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
509 memcpy(nla_data(nla), data, attrlen);
510}
511EXPORT_SYMBOL(__nla_put_64bit);
512
513/**
514 * __nla_put_nohdr - Add a netlink attribute without header
515 * @skb: socket buffer to add attribute to
516 * @attrlen: length of attribute payload
517 * @data: head of attribute payload
518 *
519 * The caller is responsible to ensure that the skb provides enough
520 * tailroom for the attribute payload.
521 */
522void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
523{
524 void *start;
525
526 start = __nla_reserve_nohdr(skb, attrlen);
527 memcpy(start, data, attrlen);
528}
529EXPORT_SYMBOL(__nla_put_nohdr);
530
531/**
532 * nla_put - Add a netlink attribute to a socket buffer
533 * @skb: socket buffer to add attribute to
534 * @attrtype: attribute type
535 * @attrlen: length of attribute payload
536 * @data: head of attribute payload
537 *
538 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
539 * the attribute header and payload.
540 */
541int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
542{
543 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
544 return -EMSGSIZE;
545
546 __nla_put(skb, attrtype, attrlen, data);
547 return 0;
548}
549EXPORT_SYMBOL(nla_put);
550
551/**
552 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
553 * @skb: socket buffer to add attribute to
554 * @attrtype: attribute type
555 * @attrlen: length of attribute payload
556 * @data: head of attribute payload
557 * @padattr: attribute type for the padding
558 *
559 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
560 * the attribute header and payload.
561 */
562int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
563 const void *data, int padattr)
564{
565 size_t len;
566
567 if (nla_need_padding_for_64bit(skb))
568 len = nla_total_size_64bit(attrlen);
569 else
570 len = nla_total_size(attrlen);
571 if (unlikely(skb_tailroom(skb) < len))
572 return -EMSGSIZE;
573
574 __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
575 return 0;
576}
577EXPORT_SYMBOL(nla_put_64bit);
578
579/**
580 * nla_put_nohdr - Add a netlink attribute without header
581 * @skb: socket buffer to add attribute to
582 * @attrlen: length of attribute payload
583 * @data: head of attribute payload
584 *
585 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
586 * the attribute payload.
587 */
588int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
589{
590 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
591 return -EMSGSIZE;
592
593 __nla_put_nohdr(skb, attrlen, data);
594 return 0;
595}
596EXPORT_SYMBOL(nla_put_nohdr);
597
598/**
599 * nla_append - Add a netlink attribute without header or padding
600 * @skb: socket buffer to add attribute to
601 * @attrlen: length of attribute payload
602 * @data: head of attribute payload
603 *
604 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
605 * the attribute payload.
606 */
607int nla_append(struct sk_buff *skb, int attrlen, const void *data)
608{
609 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
610 return -EMSGSIZE;
611
612 memcpy(skb_put(skb, attrlen), data, attrlen);
613 return 0;
614}
615EXPORT_SYMBOL(nla_append);
616#endif