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Source at commit cdde9cf73945d547acd3e96f9508c79e84ad0bf1 created 12 years 9 months ago. By Maarten ter Huurne, MMC: JZ4740: Added support for CPU frequency changing | |
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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 | |
18 | static 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 | }; |
26 | |
27 | static int validate_nla(const struct nlattr *nla, int maxtype, |
28 | const struct nla_policy *policy) |
29 | { |
30 | const struct nla_policy *pt; |
31 | int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); |
32 | |
33 | if (type <= 0 || type > maxtype) |
34 | return 0; |
35 | |
36 | pt = &policy[type]; |
37 | |
38 | BUG_ON(pt->type > NLA_TYPE_MAX); |
39 | |
40 | switch (pt->type) { |
41 | case NLA_FLAG: |
42 | if (attrlen > 0) |
43 | return -ERANGE; |
44 | break; |
45 | |
46 | case NLA_NUL_STRING: |
47 | if (pt->len) |
48 | minlen = min_t(int, attrlen, pt->len + 1); |
49 | else |
50 | minlen = attrlen; |
51 | |
52 | if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) |
53 | return -EINVAL; |
54 | /* fall through */ |
55 | |
56 | case NLA_STRING: |
57 | if (attrlen < 1) |
58 | return -ERANGE; |
59 | |
60 | if (pt->len) { |
61 | char *buf = nla_data(nla); |
62 | |
63 | if (buf[attrlen - 1] == '\0') |
64 | attrlen--; |
65 | |
66 | if (attrlen > pt->len) |
67 | return -ERANGE; |
68 | } |
69 | break; |
70 | |
71 | case NLA_BINARY: |
72 | if (pt->len && attrlen > pt->len) |
73 | return -ERANGE; |
74 | break; |
75 | |
76 | case NLA_NESTED_COMPAT: |
77 | if (attrlen < pt->len) |
78 | return -ERANGE; |
79 | if (attrlen < NLA_ALIGN(pt->len)) |
80 | break; |
81 | if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN) |
82 | return -ERANGE; |
83 | nla = nla_data(nla) + NLA_ALIGN(pt->len); |
84 | if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla)) |
85 | return -ERANGE; |
86 | break; |
87 | case NLA_NESTED: |
88 | /* a nested attributes is allowed to be empty; if its not, |
89 | * it must have a size of at least NLA_HDRLEN. |
90 | */ |
91 | if (attrlen == 0) |
92 | break; |
93 | default: |
94 | if (pt->len) |
95 | minlen = pt->len; |
96 | else if (pt->type != NLA_UNSPEC) |
97 | minlen = nla_attr_minlen[pt->type]; |
98 | |
99 | if (attrlen < minlen) |
100 | return -ERANGE; |
101 | } |
102 | |
103 | return 0; |
104 | } |
105 | |
106 | /** |
107 | * nla_validate - Validate a stream of attributes |
108 | * @head: head of attribute stream |
109 | * @len: length of attribute stream |
110 | * @maxtype: maximum attribute type to be expected |
111 | * @policy: validation policy |
112 | * |
113 | * Validates all attributes in the specified attribute stream against the |
114 | * specified policy. Attributes with a type exceeding maxtype will be |
115 | * ignored. See documenation of struct nla_policy for more details. |
116 | * |
117 | * Returns 0 on success or a negative error code. |
118 | */ |
119 | int nla_validate(const struct nlattr *head, int len, int maxtype, |
120 | const struct nla_policy *policy) |
121 | { |
122 | const struct nlattr *nla; |
123 | int rem, err; |
124 | |
125 | nla_for_each_attr(nla, head, len, rem) { |
126 | err = validate_nla(nla, maxtype, policy); |
127 | if (err < 0) |
128 | goto errout; |
129 | } |
130 | |
131 | err = 0; |
132 | errout: |
133 | return err; |
134 | } |
135 | |
136 | /** |
137 | * nla_policy_len - Determin the max. length of a policy |
138 | * @policy: policy to use |
139 | * @n: number of policies |
140 | * |
141 | * Determines the max. length of the policy. It is currently used |
142 | * to allocated Netlink buffers roughly the size of the actual |
143 | * message. |
144 | * |
145 | * Returns 0 on success or a negative error code. |
146 | */ |
147 | int |
148 | nla_policy_len(const struct nla_policy *p, int n) |
149 | { |
150 | int i, len = 0; |
151 | |
152 | for (i = 0; i < n; i++, p++) { |
153 | if (p->len) |
154 | len += nla_total_size(p->len); |
155 | else if (nla_attr_minlen[p->type]) |
156 | len += nla_total_size(nla_attr_minlen[p->type]); |
157 | } |
158 | |
159 | return len; |
160 | } |
161 | |
162 | /** |
163 | * nla_parse - Parse a stream of attributes into a tb buffer |
164 | * @tb: destination array with maxtype+1 elements |
165 | * @maxtype: maximum attribute type to be expected |
166 | * @head: head of attribute stream |
167 | * @len: length of attribute stream |
168 | * @policy: validation policy |
169 | * |
170 | * Parses a stream of attributes and stores a pointer to each attribute in |
171 | * the tb array accessible via the attribute type. Attributes with a type |
172 | * exceeding maxtype will be silently ignored for backwards compatibility |
173 | * reasons. policy may be set to NULL if no validation is required. |
174 | * |
175 | * Returns 0 on success or a negative error code. |
176 | */ |
177 | int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head, |
178 | int len, const struct nla_policy *policy) |
179 | { |
180 | const struct nlattr *nla; |
181 | int rem, err; |
182 | |
183 | memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); |
184 | |
185 | nla_for_each_attr(nla, head, len, rem) { |
186 | u16 type = nla_type(nla); |
187 | |
188 | if (type > 0 && type <= maxtype) { |
189 | if (policy) { |
190 | err = validate_nla(nla, maxtype, policy); |
191 | if (err < 0) |
192 | goto errout; |
193 | } |
194 | |
195 | tb[type] = (struct nlattr *)nla; |
196 | } |
197 | } |
198 | |
199 | if (unlikely(rem > 0)) |
200 | printk(KERN_WARNING "netlink: %d bytes leftover after parsing " |
201 | "attributes.\n", rem); |
202 | |
203 | err = 0; |
204 | errout: |
205 | return err; |
206 | } |
207 | |
208 | /** |
209 | * nla_find - Find a specific attribute in a stream of attributes |
210 | * @head: head of attribute stream |
211 | * @len: length of attribute stream |
212 | * @attrtype: type of attribute to look for |
213 | * |
214 | * Returns the first attribute in the stream matching the specified type. |
215 | */ |
216 | struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype) |
217 | { |
218 | const struct nlattr *nla; |
219 | int rem; |
220 | |
221 | nla_for_each_attr(nla, head, len, rem) |
222 | if (nla_type(nla) == attrtype) |
223 | return (struct nlattr *)nla; |
224 | |
225 | return NULL; |
226 | } |
227 | |
228 | /** |
229 | * nla_strlcpy - Copy string attribute payload into a sized buffer |
230 | * @dst: where to copy the string to |
231 | * @nla: attribute to copy the string from |
232 | * @dstsize: size of destination buffer |
233 | * |
234 | * Copies at most dstsize - 1 bytes into the destination buffer. |
235 | * The result is always a valid NUL-terminated string. Unlike |
236 | * strlcpy the destination buffer is always padded out. |
237 | * |
238 | * Returns the length of the source buffer. |
239 | */ |
240 | size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize) |
241 | { |
242 | size_t srclen = nla_len(nla); |
243 | char *src = nla_data(nla); |
244 | |
245 | if (srclen > 0 && src[srclen - 1] == '\0') |
246 | srclen--; |
247 | |
248 | if (dstsize > 0) { |
249 | size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; |
250 | |
251 | memset(dst, 0, dstsize); |
252 | memcpy(dst, src, len); |
253 | } |
254 | |
255 | return srclen; |
256 | } |
257 | |
258 | /** |
259 | * nla_memcpy - Copy a netlink attribute into another memory area |
260 | * @dest: where to copy to memcpy |
261 | * @src: netlink attribute to copy from |
262 | * @count: size of the destination area |
263 | * |
264 | * Note: The number of bytes copied is limited by the length of |
265 | * attribute's payload. memcpy |
266 | * |
267 | * Returns the number of bytes copied. |
268 | */ |
269 | int nla_memcpy(void *dest, const struct nlattr *src, int count) |
270 | { |
271 | int minlen = min_t(int, count, nla_len(src)); |
272 | |
273 | memcpy(dest, nla_data(src), minlen); |
274 | |
275 | return minlen; |
276 | } |
277 | |
278 | /** |
279 | * nla_memcmp - Compare an attribute with sized memory area |
280 | * @nla: netlink attribute |
281 | * @data: memory area |
282 | * @size: size of memory area |
283 | */ |
284 | int nla_memcmp(const struct nlattr *nla, const void *data, |
285 | size_t size) |
286 | { |
287 | int d = nla_len(nla) - size; |
288 | |
289 | if (d == 0) |
290 | d = memcmp(nla_data(nla), data, size); |
291 | |
292 | return d; |
293 | } |
294 | |
295 | /** |
296 | * nla_strcmp - Compare a string attribute against a string |
297 | * @nla: netlink string attribute |
298 | * @str: another string |
299 | */ |
300 | int nla_strcmp(const struct nlattr *nla, const char *str) |
301 | { |
302 | int len = strlen(str) + 1; |
303 | int d = nla_len(nla) - len; |
304 | |
305 | if (d == 0) |
306 | d = memcmp(nla_data(nla), str, len); |
307 | |
308 | return d; |
309 | } |
310 | |
311 | #ifdef CONFIG_NET |
312 | /** |
313 | * __nla_reserve - reserve room for attribute on the skb |
314 | * @skb: socket buffer to reserve room on |
315 | * @attrtype: attribute type |
316 | * @attrlen: length of attribute payload |
317 | * |
318 | * Adds a netlink attribute header to a socket buffer and reserves |
319 | * room for the payload but does not copy it. |
320 | * |
321 | * The caller is responsible to ensure that the skb provides enough |
322 | * tailroom for the attribute header and payload. |
323 | */ |
324 | struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) |
325 | { |
326 | struct nlattr *nla; |
327 | |
328 | nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen)); |
329 | nla->nla_type = attrtype; |
330 | nla->nla_len = nla_attr_size(attrlen); |
331 | |
332 | memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); |
333 | |
334 | return nla; |
335 | } |
336 | EXPORT_SYMBOL(__nla_reserve); |
337 | |
338 | /** |
339 | * __nla_reserve_nohdr - reserve room for attribute without header |
340 | * @skb: socket buffer to reserve room on |
341 | * @attrlen: length of attribute payload |
342 | * |
343 | * Reserves room for attribute payload without a header. |
344 | * |
345 | * The caller is responsible to ensure that the skb provides enough |
346 | * tailroom for the payload. |
347 | */ |
348 | void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) |
349 | { |
350 | void *start; |
351 | |
352 | start = skb_put(skb, NLA_ALIGN(attrlen)); |
353 | memset(start, 0, NLA_ALIGN(attrlen)); |
354 | |
355 | return start; |
356 | } |
357 | EXPORT_SYMBOL(__nla_reserve_nohdr); |
358 | |
359 | /** |
360 | * nla_reserve - reserve room for attribute on the skb |
361 | * @skb: socket buffer to reserve room on |
362 | * @attrtype: attribute type |
363 | * @attrlen: length of attribute payload |
364 | * |
365 | * Adds a netlink attribute header to a socket buffer and reserves |
366 | * room for the payload but does not copy it. |
367 | * |
368 | * Returns NULL if the tailroom of the skb is insufficient to store |
369 | * the attribute header and payload. |
370 | */ |
371 | struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) |
372 | { |
373 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) |
374 | return NULL; |
375 | |
376 | return __nla_reserve(skb, attrtype, attrlen); |
377 | } |
378 | EXPORT_SYMBOL(nla_reserve); |
379 | |
380 | /** |
381 | * nla_reserve_nohdr - reserve room for attribute without header |
382 | * @skb: socket buffer to reserve room on |
383 | * @attrlen: length of attribute payload |
384 | * |
385 | * Reserves room for attribute payload without a header. |
386 | * |
387 | * Returns NULL if the tailroom of the skb is insufficient to store |
388 | * the attribute payload. |
389 | */ |
390 | void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) |
391 | { |
392 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) |
393 | return NULL; |
394 | |
395 | return __nla_reserve_nohdr(skb, attrlen); |
396 | } |
397 | EXPORT_SYMBOL(nla_reserve_nohdr); |
398 | |
399 | /** |
400 | * __nla_put - Add a netlink attribute to a socket buffer |
401 | * @skb: socket buffer to add attribute to |
402 | * @attrtype: attribute type |
403 | * @attrlen: length of attribute payload |
404 | * @data: head of attribute payload |
405 | * |
406 | * The caller is responsible to ensure that the skb provides enough |
407 | * tailroom for the attribute header and payload. |
408 | */ |
409 | void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, |
410 | const void *data) |
411 | { |
412 | struct nlattr *nla; |
413 | |
414 | nla = __nla_reserve(skb, attrtype, attrlen); |
415 | memcpy(nla_data(nla), data, attrlen); |
416 | } |
417 | EXPORT_SYMBOL(__nla_put); |
418 | |
419 | /** |
420 | * __nla_put_nohdr - Add a netlink attribute without header |
421 | * @skb: socket buffer to add attribute to |
422 | * @attrlen: length of attribute payload |
423 | * @data: head of attribute payload |
424 | * |
425 | * The caller is responsible to ensure that the skb provides enough |
426 | * tailroom for the attribute payload. |
427 | */ |
428 | void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) |
429 | { |
430 | void *start; |
431 | |
432 | start = __nla_reserve_nohdr(skb, attrlen); |
433 | memcpy(start, data, attrlen); |
434 | } |
435 | EXPORT_SYMBOL(__nla_put_nohdr); |
436 | |
437 | /** |
438 | * nla_put - Add a netlink attribute to a socket buffer |
439 | * @skb: socket buffer to add attribute to |
440 | * @attrtype: attribute type |
441 | * @attrlen: length of attribute payload |
442 | * @data: head of attribute payload |
443 | * |
444 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
445 | * the attribute header and payload. |
446 | */ |
447 | int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) |
448 | { |
449 | if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) |
450 | return -EMSGSIZE; |
451 | |
452 | __nla_put(skb, attrtype, attrlen, data); |
453 | return 0; |
454 | } |
455 | EXPORT_SYMBOL(nla_put); |
456 | |
457 | /** |
458 | * nla_put_nohdr - Add a netlink attribute without header |
459 | * @skb: socket buffer to add attribute to |
460 | * @attrlen: length of attribute payload |
461 | * @data: head of attribute payload |
462 | * |
463 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
464 | * the attribute payload. |
465 | */ |
466 | int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) |
467 | { |
468 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) |
469 | return -EMSGSIZE; |
470 | |
471 | __nla_put_nohdr(skb, attrlen, data); |
472 | return 0; |
473 | } |
474 | EXPORT_SYMBOL(nla_put_nohdr); |
475 | |
476 | /** |
477 | * nla_append - Add a netlink attribute without header or padding |
478 | * @skb: socket buffer to add attribute to |
479 | * @attrlen: length of attribute payload |
480 | * @data: head of attribute payload |
481 | * |
482 | * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store |
483 | * the attribute payload. |
484 | */ |
485 | int nla_append(struct sk_buff *skb, int attrlen, const void *data) |
486 | { |
487 | if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) |
488 | return -EMSGSIZE; |
489 | |
490 | memcpy(skb_put(skb, attrlen), data, attrlen); |
491 | return 0; |
492 | } |
493 | EXPORT_SYMBOL(nla_append); |
494 | #endif |
495 | |
496 | EXPORT_SYMBOL(nla_validate); |
497 | EXPORT_SYMBOL(nla_policy_len); |
498 | EXPORT_SYMBOL(nla_parse); |
499 | EXPORT_SYMBOL(nla_find); |
500 | EXPORT_SYMBOL(nla_strlcpy); |
501 | EXPORT_SYMBOL(nla_memcpy); |
502 | EXPORT_SYMBOL(nla_memcmp); |
503 | EXPORT_SYMBOL(nla_strcmp); |
504 |
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