2 * NETLINK Netlink attributes
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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>
17 static const u16 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
),
30 static int validate_nla(const struct nlattr
*nla
, int maxtype
,
31 const struct nla_policy
*policy
)
33 const struct nla_policy
*pt
;
34 int minlen
= 0, attrlen
= nla_len(nla
), type
= nla_type(nla
);
36 if (type
<= 0 || type
> maxtype
)
41 BUG_ON(pt
->type
> NLA_TYPE_MAX
);
51 minlen
= min_t(int, attrlen
, pt
->len
+ 1);
55 if (!minlen
|| memchr(nla_data(nla
), '\0', minlen
) == NULL
)
64 char *buf
= nla_data(nla
);
66 if (buf
[attrlen
- 1] == '\0')
69 if (attrlen
> pt
->len
)
75 if (pt
->len
&& attrlen
> pt
->len
)
79 case NLA_NESTED_COMPAT
:
80 if (attrlen
< pt
->len
)
82 if (attrlen
< NLA_ALIGN(pt
->len
))
84 if (attrlen
< NLA_ALIGN(pt
->len
) + NLA_HDRLEN
)
86 nla
= nla_data(nla
) + NLA_ALIGN(pt
->len
);
87 if (attrlen
< NLA_ALIGN(pt
->len
) + NLA_HDRLEN
+ nla_len(nla
))
91 /* a nested attributes is allowed to be empty; if its not,
92 * it must have a size of at least NLA_HDRLEN.
99 else if (pt
->type
!= NLA_UNSPEC
)
100 minlen
= nla_attr_minlen
[pt
->type
];
102 if (attrlen
< minlen
)
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
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.
120 * Returns 0 on success or a negative error code.
122 int nla_validate(const struct nlattr
*head
, int len
, int maxtype
,
123 const struct nla_policy
*policy
)
125 const struct nlattr
*nla
;
128 nla_for_each_attr(nla
, head
, len
, rem
) {
129 err
= validate_nla(nla
, maxtype
, policy
);
138 EXPORT_SYMBOL(nla_validate
);
141 * nla_policy_len - Determin the max. length of a policy
142 * @policy: policy to use
143 * @n: number of policies
145 * Determines the max. length of the policy. It is currently used
146 * to allocated Netlink buffers roughly the size of the actual
149 * Returns 0 on success or a negative error code.
152 nla_policy_len(const struct nla_policy
*p
, int n
)
156 for (i
= 0; i
< n
; i
++, p
++) {
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
]);
165 EXPORT_SYMBOL(nla_policy_len
);
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
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.
180 * Returns 0 on success or a negative error code.
182 int nla_parse(struct nlattr
**tb
, int maxtype
, const struct nlattr
*head
,
183 int len
, const struct nla_policy
*policy
)
185 const struct nlattr
*nla
;
188 memset(tb
, 0, sizeof(struct nlattr
*) * (maxtype
+ 1));
190 nla_for_each_attr(nla
, head
, len
, rem
) {
191 u16 type
= nla_type(nla
);
193 if (type
> 0 && type
<= maxtype
) {
195 err
= validate_nla(nla
, maxtype
, policy
);
200 tb
[type
] = (struct nlattr
*)nla
;
204 if (unlikely(rem
> 0))
205 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
212 EXPORT_SYMBOL(nla_parse
);
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
220 * Returns the first attribute in the stream matching the specified type.
222 struct nlattr
*nla_find(const struct nlattr
*head
, int len
, int attrtype
)
224 const struct nlattr
*nla
;
227 nla_for_each_attr(nla
, head
, len
, rem
)
228 if (nla_type(nla
) == attrtype
)
229 return (struct nlattr
*)nla
;
233 EXPORT_SYMBOL(nla_find
);
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
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.
245 * Returns the length of the source buffer.
247 size_t nla_strlcpy(char *dst
, const struct nlattr
*nla
, size_t dstsize
)
249 size_t srclen
= nla_len(nla
);
250 char *src
= nla_data(nla
);
252 if (srclen
> 0 && src
[srclen
- 1] == '\0')
256 size_t len
= (srclen
>= dstsize
) ? dstsize
- 1 : srclen
;
258 memset(dst
, 0, dstsize
);
259 memcpy(dst
, src
, len
);
264 EXPORT_SYMBOL(nla_strlcpy
);
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
272 * Note: The number of bytes copied is limited by the length of
273 * attribute's payload. memcpy
275 * Returns the number of bytes copied.
277 int nla_memcpy(void *dest
, const struct nlattr
*src
, int count
)
279 int minlen
= min_t(int, count
, nla_len(src
));
281 memcpy(dest
, nla_data(src
), minlen
);
283 memset(dest
+ minlen
, 0, count
- minlen
);
287 EXPORT_SYMBOL(nla_memcpy
);
290 * nla_memcmp - Compare an attribute with sized memory area
291 * @nla: netlink attribute
293 * @size: size of memory area
295 int nla_memcmp(const struct nlattr
*nla
, const void *data
,
298 int d
= nla_len(nla
) - size
;
301 d
= memcmp(nla_data(nla
), data
, size
);
305 EXPORT_SYMBOL(nla_memcmp
);
308 * nla_strcmp - Compare a string attribute against a string
309 * @nla: netlink string attribute
310 * @str: another string
312 int nla_strcmp(const struct nlattr
*nla
, const char *str
)
314 int len
= strlen(str
);
315 char *buf
= nla_data(nla
);
316 int attrlen
= nla_len(nla
);
319 if (attrlen
> 0 && buf
[attrlen
- 1] == '\0')
324 d
= memcmp(nla_data(nla
), str
, len
);
328 EXPORT_SYMBOL(nla_strcmp
);
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
337 * Adds a netlink attribute header to a socket buffer and reserves
338 * room for the payload but does not copy it.
340 * The caller is responsible to ensure that the skb provides enough
341 * tailroom for the attribute header and payload.
343 struct nlattr
*__nla_reserve(struct sk_buff
*skb
, int attrtype
, int attrlen
)
347 nla
= (struct nlattr
*) skb_put(skb
, nla_total_size(attrlen
));
348 nla
->nla_type
= attrtype
;
349 nla
->nla_len
= nla_attr_size(attrlen
);
351 memset((unsigned char *) nla
+ nla
->nla_len
, 0, nla_padlen(attrlen
));
355 EXPORT_SYMBOL(__nla_reserve
);
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
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.
368 * The caller is responsible to ensure that the skb provides enough
369 * tailroom for the attribute header and payload.
371 struct nlattr
*__nla_reserve_64bit(struct sk_buff
*skb
, int attrtype
,
372 int attrlen
, int padattr
)
374 if (nla_need_padding_for_64bit(skb
))
375 nla_align_64bit(skb
, padattr
);
377 return __nla_reserve(skb
, attrtype
, attrlen
);
379 EXPORT_SYMBOL(__nla_reserve_64bit
);
382 * __nla_reserve_nohdr - reserve room for attribute without header
383 * @skb: socket buffer to reserve room on
384 * @attrlen: length of attribute payload
386 * Reserves room for attribute payload without a header.
388 * The caller is responsible to ensure that the skb provides enough
389 * tailroom for the payload.
391 void *__nla_reserve_nohdr(struct sk_buff
*skb
, int attrlen
)
395 start
= skb_put(skb
, NLA_ALIGN(attrlen
));
396 memset(start
, 0, NLA_ALIGN(attrlen
));
400 EXPORT_SYMBOL(__nla_reserve_nohdr
);
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
408 * Adds a netlink attribute header to a socket buffer and reserves
409 * room for the payload but does not copy it.
411 * Returns NULL if the tailroom of the skb is insufficient to store
412 * the attribute header and payload.
414 struct nlattr
*nla_reserve(struct sk_buff
*skb
, int attrtype
, int attrlen
)
416 if (unlikely(skb_tailroom(skb
) < nla_total_size(attrlen
)))
419 return __nla_reserve(skb
, attrtype
, attrlen
);
421 EXPORT_SYMBOL(nla_reserve
);
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
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.
434 * Returns NULL if the tailroom of the skb is insufficient to store
435 * the attribute header and payload.
437 struct nlattr
*nla_reserve_64bit(struct sk_buff
*skb
, int attrtype
, int attrlen
,
442 if (nla_need_padding_for_64bit(skb
))
443 len
= nla_total_size_64bit(attrlen
);
445 len
= nla_total_size(attrlen
);
446 if (unlikely(skb_tailroom(skb
) < len
))
449 return __nla_reserve_64bit(skb
, attrtype
, attrlen
, padattr
);
451 EXPORT_SYMBOL(nla_reserve_64bit
);
454 * nla_reserve_nohdr - reserve room for attribute without header
455 * @skb: socket buffer to reserve room on
456 * @attrlen: length of attribute payload
458 * Reserves room for attribute payload without a header.
460 * Returns NULL if the tailroom of the skb is insufficient to store
461 * the attribute payload.
463 void *nla_reserve_nohdr(struct sk_buff
*skb
, int attrlen
)
465 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
468 return __nla_reserve_nohdr(skb
, attrlen
);
470 EXPORT_SYMBOL(nla_reserve_nohdr
);
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
479 * The caller is responsible to ensure that the skb provides enough
480 * tailroom for the attribute header and payload.
482 void __nla_put(struct sk_buff
*skb
, int attrtype
, int attrlen
,
487 nla
= __nla_reserve(skb
, attrtype
, attrlen
);
488 memcpy(nla_data(nla
), data
, attrlen
);
490 EXPORT_SYMBOL(__nla_put
);
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
500 * The caller is responsible to ensure that the skb provides enough
501 * tailroom for the attribute header and payload.
503 void __nla_put_64bit(struct sk_buff
*skb
, int attrtype
, int attrlen
,
504 const void *data
, int padattr
)
508 nla
= __nla_reserve_64bit(skb
, attrtype
, attrlen
, padattr
);
509 memcpy(nla_data(nla
), data
, attrlen
);
511 EXPORT_SYMBOL(__nla_put_64bit
);
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
519 * The caller is responsible to ensure that the skb provides enough
520 * tailroom for the attribute payload.
522 void __nla_put_nohdr(struct sk_buff
*skb
, int attrlen
, const void *data
)
526 start
= __nla_reserve_nohdr(skb
, attrlen
);
527 memcpy(start
, data
, attrlen
);
529 EXPORT_SYMBOL(__nla_put_nohdr
);
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
538 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
539 * the attribute header and payload.
541 int nla_put(struct sk_buff
*skb
, int attrtype
, int attrlen
, const void *data
)
543 if (unlikely(skb_tailroom(skb
) < nla_total_size(attrlen
)))
546 __nla_put(skb
, attrtype
, attrlen
, data
);
549 EXPORT_SYMBOL(nla_put
);
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
559 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
560 * the attribute header and payload.
562 int nla_put_64bit(struct sk_buff
*skb
, int attrtype
, int attrlen
,
563 const void *data
, int padattr
)
567 if (nla_need_padding_for_64bit(skb
))
568 len
= nla_total_size_64bit(attrlen
);
570 len
= nla_total_size(attrlen
);
571 if (unlikely(skb_tailroom(skb
) < len
))
574 __nla_put_64bit(skb
, attrtype
, attrlen
, data
, padattr
);
577 EXPORT_SYMBOL(nla_put_64bit
);
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
585 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
586 * the attribute payload.
588 int nla_put_nohdr(struct sk_buff
*skb
, int attrlen
, const void *data
)
590 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
593 __nla_put_nohdr(skb
, attrlen
, data
);
596 EXPORT_SYMBOL(nla_put_nohdr
);
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
604 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
605 * the attribute payload.
607 int nla_append(struct sk_buff
*skb
, int attrlen
, const void *data
)
609 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
612 memcpy(skb_put(skb
, attrlen
), data
, attrlen
);
615 EXPORT_SYMBOL(nla_append
);