]>
git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - lib/nlattr.c
2 * NETLINK Netlink attributes
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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>
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_NESTED
] = NLA_HDRLEN
,
26 static int validate_nla(const struct nlattr
*nla
, int maxtype
,
27 const struct nla_policy
*policy
)
29 const struct nla_policy
*pt
;
30 int minlen
= 0, attrlen
= nla_len(nla
), type
= nla_type(nla
);
32 if (type
<= 0 || type
> maxtype
)
37 BUG_ON(pt
->type
> NLA_TYPE_MAX
);
47 minlen
= min_t(int, attrlen
, pt
->len
+ 1);
51 if (!minlen
|| memchr(nla_data(nla
), '\0', minlen
) == NULL
)
60 char *buf
= nla_data(nla
);
62 if (buf
[attrlen
- 1] == '\0')
65 if (attrlen
> pt
->len
)
71 if (pt
->len
&& attrlen
> pt
->len
)
75 case NLA_NESTED_COMPAT
:
76 if (attrlen
< pt
->len
)
78 if (attrlen
< NLA_ALIGN(pt
->len
))
80 if (attrlen
< NLA_ALIGN(pt
->len
) + NLA_HDRLEN
)
82 nla
= nla_data(nla
) + NLA_ALIGN(pt
->len
);
83 if (attrlen
< NLA_ALIGN(pt
->len
) + NLA_HDRLEN
+ nla_len(nla
))
87 /* a nested attributes is allowed to be empty; if its not,
88 * it must have a size of at least NLA_HDRLEN.
95 else if (pt
->type
!= NLA_UNSPEC
)
96 minlen
= nla_attr_minlen
[pt
->type
];
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
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.
116 * Returns 0 on success or a negative error code.
118 int nla_validate(const struct nlattr
*head
, int len
, int maxtype
,
119 const struct nla_policy
*policy
)
121 const struct nlattr
*nla
;
124 nla_for_each_attr(nla
, head
, len
, rem
) {
125 err
= validate_nla(nla
, maxtype
, policy
);
136 * nla_policy_len - Determin the max. length of a policy
137 * @policy: policy to use
138 * @n: number of policies
140 * Determines the max. length of the policy. It is currently used
141 * to allocated Netlink buffers roughly the size of the actual
144 * Returns 0 on success or a negative error code.
147 nla_policy_len(const struct nla_policy
*p
, int n
)
151 for (i
= 0; i
< n
; i
++, p
++) {
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
]);
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
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.
174 * Returns 0 on success or a negative error code.
176 int nla_parse(struct nlattr
**tb
, int maxtype
, const struct nlattr
*head
,
177 int len
, const struct nla_policy
*policy
)
179 const struct nlattr
*nla
;
182 memset(tb
, 0, sizeof(struct nlattr
*) * (maxtype
+ 1));
184 nla_for_each_attr(nla
, head
, len
, rem
) {
185 u16 type
= nla_type(nla
);
187 if (type
> 0 && type
<= maxtype
) {
189 err
= validate_nla(nla
, maxtype
, policy
);
194 tb
[type
] = (struct nlattr
*)nla
;
198 if (unlikely(rem
> 0))
199 printk(KERN_WARNING
"netlink: %d bytes leftover after parsing "
200 "attributes.\n", rem
);
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
213 * Returns the first attribute in the stream matching the specified type.
215 struct nlattr
*nla_find(const struct nlattr
*head
, int len
, int attrtype
)
217 const struct nlattr
*nla
;
220 nla_for_each_attr(nla
, head
, len
, rem
)
221 if (nla_type(nla
) == attrtype
)
222 return (struct nlattr
*)nla
;
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
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.
237 * Returns the length of the source buffer.
239 size_t nla_strlcpy(char *dst
, const struct nlattr
*nla
, size_t dstsize
)
241 size_t srclen
= nla_len(nla
);
242 char *src
= nla_data(nla
);
244 if (srclen
> 0 && src
[srclen
- 1] == '\0')
248 size_t len
= (srclen
>= dstsize
) ? dstsize
- 1 : srclen
;
250 memset(dst
, 0, dstsize
);
251 memcpy(dst
, src
, len
);
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
263 * Note: The number of bytes copied is limited by the length of
264 * attribute's payload. memcpy
266 * Returns the number of bytes copied.
268 int nla_memcpy(void *dest
, const struct nlattr
*src
, int count
)
270 int minlen
= min_t(int, count
, nla_len(src
));
272 memcpy(dest
, nla_data(src
), minlen
);
278 * nla_memcmp - Compare an attribute with sized memory area
279 * @nla: netlink attribute
281 * @size: size of memory area
283 int nla_memcmp(const struct nlattr
*nla
, const void *data
,
286 int d
= nla_len(nla
) - size
;
289 d
= memcmp(nla_data(nla
), data
, size
);
295 * nla_strcmp - Compare a string attribute against a string
296 * @nla: netlink string attribute
297 * @str: another string
299 int nla_strcmp(const struct nlattr
*nla
, const char *str
)
301 int len
= strlen(str
) + 1;
302 int d
= nla_len(nla
) - len
;
305 d
= memcmp(nla_data(nla
), str
, len
);
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
317 * Adds a netlink attribute header to a socket buffer and reserves
318 * room for the payload but does not copy it.
320 * The caller is responsible to ensure that the skb provides enough
321 * tailroom for the attribute header and payload.
323 struct nlattr
*__nla_reserve(struct sk_buff
*skb
, int attrtype
, int attrlen
)
327 nla
= (struct nlattr
*) skb_put(skb
, nla_total_size(attrlen
));
328 nla
->nla_type
= attrtype
;
329 nla
->nla_len
= nla_attr_size(attrlen
);
331 memset((unsigned char *) nla
+ nla
->nla_len
, 0, nla_padlen(attrlen
));
335 EXPORT_SYMBOL(__nla_reserve
);
338 * __nla_reserve_nohdr - reserve room for attribute without header
339 * @skb: socket buffer to reserve room on
340 * @attrlen: length of attribute payload
342 * Reserves room for attribute payload without a header.
344 * The caller is responsible to ensure that the skb provides enough
345 * tailroom for the payload.
347 void *__nla_reserve_nohdr(struct sk_buff
*skb
, int attrlen
)
351 start
= skb_put(skb
, NLA_ALIGN(attrlen
));
352 memset(start
, 0, NLA_ALIGN(attrlen
));
356 EXPORT_SYMBOL(__nla_reserve_nohdr
);
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
364 * Adds a netlink attribute header to a socket buffer and reserves
365 * room for the payload but does not copy it.
367 * Returns NULL if the tailroom of the skb is insufficient to store
368 * the attribute header and payload.
370 struct nlattr
*nla_reserve(struct sk_buff
*skb
, int attrtype
, int attrlen
)
372 if (unlikely(skb_tailroom(skb
) < nla_total_size(attrlen
)))
375 return __nla_reserve(skb
, attrtype
, attrlen
);
377 EXPORT_SYMBOL(nla_reserve
);
380 * nla_reserve_nohdr - reserve room for attribute without header
381 * @skb: socket buffer to reserve room on
382 * @attrlen: length of attribute payload
384 * Reserves room for attribute payload without a header.
386 * Returns NULL if the tailroom of the skb is insufficient to store
387 * the attribute payload.
389 void *nla_reserve_nohdr(struct sk_buff
*skb
, int attrlen
)
391 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
394 return __nla_reserve_nohdr(skb
, attrlen
);
396 EXPORT_SYMBOL(nla_reserve_nohdr
);
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
405 * The caller is responsible to ensure that the skb provides enough
406 * tailroom for the attribute header and payload.
408 void __nla_put(struct sk_buff
*skb
, int attrtype
, int attrlen
,
413 nla
= __nla_reserve(skb
, attrtype
, attrlen
);
414 memcpy(nla_data(nla
), data
, attrlen
);
416 EXPORT_SYMBOL(__nla_put
);
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
424 * The caller is responsible to ensure that the skb provides enough
425 * tailroom for the attribute payload.
427 void __nla_put_nohdr(struct sk_buff
*skb
, int attrlen
, const void *data
)
431 start
= __nla_reserve_nohdr(skb
, attrlen
);
432 memcpy(start
, data
, attrlen
);
434 EXPORT_SYMBOL(__nla_put_nohdr
);
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
443 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
444 * the attribute header and payload.
446 int nla_put(struct sk_buff
*skb
, int attrtype
, int attrlen
, const void *data
)
448 if (unlikely(skb_tailroom(skb
) < nla_total_size(attrlen
)))
451 __nla_put(skb
, attrtype
, attrlen
, data
);
454 EXPORT_SYMBOL(nla_put
);
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
462 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
463 * the attribute payload.
465 int nla_put_nohdr(struct sk_buff
*skb
, int attrlen
, const void *data
)
467 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
470 __nla_put_nohdr(skb
, attrlen
, data
);
473 EXPORT_SYMBOL(nla_put_nohdr
);
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
481 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
482 * the attribute payload.
484 int nla_append(struct sk_buff
*skb
, int attrlen
, const void *data
)
486 if (unlikely(skb_tailroom(skb
) < NLA_ALIGN(attrlen
)))
489 memcpy(skb_put(skb
, attrlen
), data
, attrlen
);
492 EXPORT_SYMBOL(nla_append
);
495 EXPORT_SYMBOL(nla_validate
);
496 EXPORT_SYMBOL(nla_policy_len
);
497 EXPORT_SYMBOL(nla_parse
);
498 EXPORT_SYMBOL(nla_find
);
499 EXPORT_SYMBOL(nla_strlcpy
);
500 EXPORT_SYMBOL(nla_memcpy
);
501 EXPORT_SYMBOL(nla_memcmp
);
502 EXPORT_SYMBOL(nla_strcmp
);