ixgbe: Add support for IPv6 and UDP to ixgbe_get_headlen
[linux-2.6/cjktty.git] / lib / nlattr.c
blob18eca7809b08894cd135519f8991e138bbc0fa2a
1 /*
2 * NETLINK Netlink attributes
4 * Authors: Thomas Graf <tgraf@suug.ch>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 */
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>
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 [NLA_S8] = sizeof(s8),
26 [NLA_S16] = sizeof(s16),
27 [NLA_S32] = sizeof(s32),
28 [NLA_S64] = sizeof(s64),
31 static int validate_nla(const struct nlattr *nla, int maxtype,
32 const struct nla_policy *policy)
34 const struct nla_policy *pt;
35 int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
37 if (type <= 0 || type > maxtype)
38 return 0;
40 pt = &policy[type];
42 BUG_ON(pt->type > NLA_TYPE_MAX);
44 switch (pt->type) {
45 case NLA_FLAG:
46 if (attrlen > 0)
47 return -ERANGE;
48 break;
50 case NLA_NUL_STRING:
51 if (pt->len)
52 minlen = min_t(int, attrlen, pt->len + 1);
53 else
54 minlen = attrlen;
56 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
57 return -EINVAL;
58 /* fall through */
60 case NLA_STRING:
61 if (attrlen < 1)
62 return -ERANGE;
64 if (pt->len) {
65 char *buf = nla_data(nla);
67 if (buf[attrlen - 1] == '\0')
68 attrlen--;
70 if (attrlen > pt->len)
71 return -ERANGE;
73 break;
75 case NLA_BINARY:
76 if (pt->len && attrlen > pt->len)
77 return -ERANGE;
78 break;
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.
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];
103 if (attrlen < minlen)
104 return -ERANGE;
107 return 0;
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
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.
121 * Returns 0 on success or a negative error code.
123 int nla_validate(const struct nlattr *head, int len, int maxtype,
124 const struct nla_policy *policy)
126 const struct nlattr *nla;
127 int rem, err;
129 nla_for_each_attr(nla, head, len, rem) {
130 err = validate_nla(nla, maxtype, policy);
131 if (err < 0)
132 goto errout;
135 err = 0;
136 errout:
137 return err;
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
147 * message.
149 * Returns 0 on success or a negative error code.
152 nla_policy_len(const struct nla_policy *p, int n)
154 int i, len = 0;
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]);
163 return len;
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
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.
179 * Returns 0 on success or a negative error code.
181 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
182 int len, const struct nla_policy *policy)
184 const struct nlattr *nla;
185 int rem, err;
187 memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
189 nla_for_each_attr(nla, head, len, rem) {
190 u16 type = nla_type(nla);
192 if (type > 0 && type <= maxtype) {
193 if (policy) {
194 err = validate_nla(nla, maxtype, policy);
195 if (err < 0)
196 goto errout;
199 tb[type] = (struct nlattr *)nla;
203 if (unlikely(rem > 0))
204 printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
205 "attributes.\n", rem);
207 err = 0;
208 errout:
209 return err;
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
218 * Returns the first attribute in the stream matching the specified type.
220 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
222 const struct nlattr *nla;
223 int rem;
225 nla_for_each_attr(nla, head, len, rem)
226 if (nla_type(nla) == attrtype)
227 return (struct nlattr *)nla;
229 return NULL;
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
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.
242 * Returns the length of the source buffer.
244 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
246 size_t srclen = nla_len(nla);
247 char *src = nla_data(nla);
249 if (srclen > 0 && src[srclen - 1] == '\0')
250 srclen--;
252 if (dstsize > 0) {
253 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
255 memset(dst, 0, dstsize);
256 memcpy(dst, src, len);
259 return srclen;
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
268 * Note: The number of bytes copied is limited by the length of
269 * attribute's payload. memcpy
271 * Returns the number of bytes copied.
273 int nla_memcpy(void *dest, const struct nlattr *src, int count)
275 int minlen = min_t(int, count, nla_len(src));
277 memcpy(dest, nla_data(src), minlen);
279 return minlen;
283 * nla_memcmp - Compare an attribute with sized memory area
284 * @nla: netlink attribute
285 * @data: memory area
286 * @size: size of memory area
288 int nla_memcmp(const struct nlattr *nla, const void *data,
289 size_t size)
291 int d = nla_len(nla) - size;
293 if (d == 0)
294 d = memcmp(nla_data(nla), data, size);
296 return d;
300 * nla_strcmp - Compare a string attribute against a string
301 * @nla: netlink string attribute
302 * @str: another string
304 int nla_strcmp(const struct nlattr *nla, const char *str)
306 int len = strlen(str) + 1;
307 int d = nla_len(nla) - len;
309 if (d == 0)
310 d = memcmp(nla_data(nla), str, len);
312 return d;
315 #ifdef CONFIG_NET
317 * __nla_reserve - reserve room for attribute on the skb
318 * @skb: socket buffer to reserve room on
319 * @attrtype: attribute type
320 * @attrlen: length of attribute payload
322 * Adds a netlink attribute header to a socket buffer and reserves
323 * room for the payload but does not copy it.
325 * The caller is responsible to ensure that the skb provides enough
326 * tailroom for the attribute header and payload.
328 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
330 struct nlattr *nla;
332 nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
333 nla->nla_type = attrtype;
334 nla->nla_len = nla_attr_size(attrlen);
336 memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
338 return nla;
340 EXPORT_SYMBOL(__nla_reserve);
343 * __nla_reserve_nohdr - reserve room for attribute without header
344 * @skb: socket buffer to reserve room on
345 * @attrlen: length of attribute payload
347 * Reserves room for attribute payload without a header.
349 * The caller is responsible to ensure that the skb provides enough
350 * tailroom for the payload.
352 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
354 void *start;
356 start = skb_put(skb, NLA_ALIGN(attrlen));
357 memset(start, 0, NLA_ALIGN(attrlen));
359 return start;
361 EXPORT_SYMBOL(__nla_reserve_nohdr);
364 * nla_reserve - reserve room for attribute on the skb
365 * @skb: socket buffer to reserve room on
366 * @attrtype: attribute type
367 * @attrlen: length of attribute payload
369 * Adds a netlink attribute header to a socket buffer and reserves
370 * room for the payload but does not copy it.
372 * Returns NULL if the tailroom of the skb is insufficient to store
373 * the attribute header and payload.
375 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
377 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
378 return NULL;
380 return __nla_reserve(skb, attrtype, attrlen);
382 EXPORT_SYMBOL(nla_reserve);
385 * nla_reserve_nohdr - reserve room for attribute without header
386 * @skb: socket buffer to reserve room on
387 * @attrlen: length of attribute payload
389 * Reserves room for attribute payload without a header.
391 * Returns NULL if the tailroom of the skb is insufficient to store
392 * the attribute payload.
394 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
396 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
397 return NULL;
399 return __nla_reserve_nohdr(skb, attrlen);
401 EXPORT_SYMBOL(nla_reserve_nohdr);
404 * __nla_put - Add a netlink attribute to a socket buffer
405 * @skb: socket buffer to add attribute to
406 * @attrtype: attribute type
407 * @attrlen: length of attribute payload
408 * @data: head of attribute payload
410 * The caller is responsible to ensure that the skb provides enough
411 * tailroom for the attribute header and payload.
413 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
414 const void *data)
416 struct nlattr *nla;
418 nla = __nla_reserve(skb, attrtype, attrlen);
419 memcpy(nla_data(nla), data, attrlen);
421 EXPORT_SYMBOL(__nla_put);
424 * __nla_put_nohdr - Add a netlink attribute without header
425 * @skb: socket buffer to add attribute to
426 * @attrlen: length of attribute payload
427 * @data: head of attribute payload
429 * The caller is responsible to ensure that the skb provides enough
430 * tailroom for the attribute payload.
432 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
434 void *start;
436 start = __nla_reserve_nohdr(skb, attrlen);
437 memcpy(start, data, attrlen);
439 EXPORT_SYMBOL(__nla_put_nohdr);
442 * nla_put - Add a netlink attribute to a socket buffer
443 * @skb: socket buffer to add attribute to
444 * @attrtype: attribute type
445 * @attrlen: length of attribute payload
446 * @data: head of attribute payload
448 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
449 * the attribute header and payload.
451 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
453 if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
454 return -EMSGSIZE;
456 __nla_put(skb, attrtype, attrlen, data);
457 return 0;
459 EXPORT_SYMBOL(nla_put);
462 * nla_put_nohdr - Add a netlink attribute without header
463 * @skb: socket buffer to add attribute to
464 * @attrlen: length of attribute payload
465 * @data: head of attribute payload
467 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
468 * the attribute payload.
470 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
472 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
473 return -EMSGSIZE;
475 __nla_put_nohdr(skb, attrlen, data);
476 return 0;
478 EXPORT_SYMBOL(nla_put_nohdr);
481 * nla_append - Add a netlink attribute without header or padding
482 * @skb: socket buffer to add attribute to
483 * @attrlen: length of attribute payload
484 * @data: head of attribute payload
486 * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
487 * the attribute payload.
489 int nla_append(struct sk_buff *skb, int attrlen, const void *data)
491 if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
492 return -EMSGSIZE;
494 memcpy(skb_put(skb, attrlen), data, attrlen);
495 return 0;
497 EXPORT_SYMBOL(nla_append);
498 #endif
500 EXPORT_SYMBOL(nla_validate);
501 EXPORT_SYMBOL(nla_policy_len);
502 EXPORT_SYMBOL(nla_parse);
503 EXPORT_SYMBOL(nla_find);
504 EXPORT_SYMBOL(nla_strlcpy);
505 EXPORT_SYMBOL(nla_memcpy);
506 EXPORT_SYMBOL(nla_memcmp);
507 EXPORT_SYMBOL(nla_strcmp);