1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __NET_NETLINK_H
3#define __NET_NETLINK_H
4
5#include <linux/types.h>
6#include <linux/netlink.h>
7#include <linux/jiffies.h>
8#include <linux/in6.h>
9
10/* ========================================================================
11 * Netlink Messages and Attributes Interface (As Seen On TV)
12 * ------------------------------------------------------------------------
13 * Messages Interface
14 * ------------------------------------------------------------------------
15 *
16 * Message Format:
17 * <--- nlmsg_total_size(payload) --->
18 * <-- nlmsg_msg_size(payload) ->
19 * +----------+- - -+-------------+- - -+-------- - -
20 * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
21 * +----------+- - -+-------------+- - -+-------- - -
22 * nlmsg_data(nlh)---^ ^
23 * nlmsg_next(nlh)-----------------------+
24 *
25 * Payload Format:
26 * <---------------------- nlmsg_len(nlh) --------------------->
27 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
28 * +----------------------+- - -+--------------------------------+
29 * | Family Header | Pad | Attributes |
30 * +----------------------+- - -+--------------------------------+
31 * nlmsg_attrdata(nlh, hdrlen)---^
32 *
33 * Data Structures:
34 * struct nlmsghdr netlink message header
35 *
36 * Message Construction:
37 * nlmsg_new() create a new netlink message
38 * nlmsg_put() add a netlink message to an skb
39 * nlmsg_put_answer() callback based nlmsg_put()
40 * nlmsg_end() finalize netlink message
41 * nlmsg_get_pos() return current position in message
42 * nlmsg_trim() trim part of message
43 * nlmsg_cancel() cancel message construction
44 * nlmsg_free() free a netlink message
45 *
46 * Message Sending:
47 * nlmsg_multicast() multicast message to several groups
48 * nlmsg_unicast() unicast a message to a single socket
49 * nlmsg_notify() send notification message
50 *
51 * Message Length Calculations:
52 * nlmsg_msg_size(payload) length of message w/o padding
53 * nlmsg_total_size(payload) length of message w/ padding
54 * nlmsg_padlen(payload) length of padding at tail
55 *
56 * Message Payload Access:
57 * nlmsg_data(nlh) head of message payload
58 * nlmsg_len(nlh) length of message payload
59 * nlmsg_attrdata(nlh, hdrlen) head of attributes data
60 * nlmsg_attrlen(nlh, hdrlen) length of attributes data
61 *
62 * Message Parsing:
63 * nlmsg_ok(nlh, remaining) does nlh fit into remaining bytes?
64 * nlmsg_next(nlh, remaining) get next netlink message
65 * nlmsg_parse() parse attributes of a message
66 * nlmsg_find_attr() find an attribute in a message
67 * nlmsg_for_each_msg() loop over all messages
68 * nlmsg_validate() validate netlink message incl. attrs
69 * nlmsg_for_each_attr() loop over all attributes
70 *
71 * Misc:
72 * nlmsg_report() report back to application?
73 *
74 * ------------------------------------------------------------------------
75 * Attributes Interface
76 * ------------------------------------------------------------------------
77 *
78 * Attribute Format:
79 * <------- nla_total_size(payload) ------->
80 * <---- nla_attr_size(payload) ----->
81 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
82 * | Header | Pad | Payload | Pad | Header
83 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
84 * <- nla_len(nla) -> ^
85 * nla_data(nla)----^ |
86 * nla_next(nla)-----------------------------'
87 *
88 * Data Structures:
89 * struct nlattr netlink attribute header
90 *
91 * Attribute Construction:
92 * nla_reserve(skb, type, len) reserve room for an attribute
93 * nla_reserve_nohdr(skb, len) reserve room for an attribute w/o hdr
94 * nla_put(skb, type, len, data) add attribute to skb
95 * nla_put_nohdr(skb, len, data) add attribute w/o hdr
96 * nla_append(skb, len, data) append data to skb
97 *
98 * Attribute Construction for Basic Types:
99 * nla_put_u8(skb, type, value) add u8 attribute to skb
100 * nla_put_u16(skb, type, value) add u16 attribute to skb
101 * nla_put_u32(skb, type, value) add u32 attribute to skb
102 * nla_put_u64_64bit(skb, type,
103 * value, padattr) add u64 attribute to skb
104 * nla_put_s8(skb, type, value) add s8 attribute to skb
105 * nla_put_s16(skb, type, value) add s16 attribute to skb
106 * nla_put_s32(skb, type, value) add s32 attribute to skb
107 * nla_put_s64(skb, type, value,
108 * padattr) add s64 attribute to skb
109 * nla_put_string(skb, type, str) add string attribute to skb
110 * nla_put_flag(skb, type) add flag attribute to skb
111 * nla_put_msecs(skb, type, jiffies,
112 * padattr) add msecs attribute to skb
113 * nla_put_in_addr(skb, type, addr) add IPv4 address attribute to skb
114 * nla_put_in6_addr(skb, type, addr) add IPv6 address attribute to skb
115 *
116 * Nested Attributes Construction:
117 * nla_nest_start(skb, type) start a nested attribute
118 * nla_nest_end(skb, nla) finalize a nested attribute
119 * nla_nest_cancel(skb, nla) cancel nested attribute construction
120 *
121 * Attribute Length Calculations:
122 * nla_attr_size(payload) length of attribute w/o padding
123 * nla_total_size(payload) length of attribute w/ padding
124 * nla_padlen(payload) length of padding
125 *
126 * Attribute Payload Access:
127 * nla_data(nla) head of attribute payload
128 * nla_len(nla) length of attribute payload
129 *
130 * Attribute Payload Access for Basic Types:
131 * nla_get_u8(nla) get payload for a u8 attribute
132 * nla_get_u16(nla) get payload for a u16 attribute
133 * nla_get_u32(nla) get payload for a u32 attribute
134 * nla_get_u64(nla) get payload for a u64 attribute
135 * nla_get_s8(nla) get payload for a s8 attribute
136 * nla_get_s16(nla) get payload for a s16 attribute
137 * nla_get_s32(nla) get payload for a s32 attribute
138 * nla_get_s64(nla) get payload for a s64 attribute
139 * nla_get_flag(nla) return 1 if flag is true
140 * nla_get_msecs(nla) get payload for a msecs attribute
141 *
142 * Attribute Misc:
143 * nla_memcpy(dest, nla, count) copy attribute into memory
144 * nla_memcmp(nla, data, size) compare attribute with memory area
145 * nla_strlcpy(dst, nla, size) copy attribute to a sized string
146 * nla_strcmp(nla, str) compare attribute with string
147 *
148 * Attribute Parsing:
149 * nla_ok(nla, remaining) does nla fit into remaining bytes?
150 * nla_next(nla, remaining) get next netlink attribute
151 * nla_validate() validate a stream of attributes
152 * nla_validate_nested() validate a stream of nested attributes
153 * nla_find() find attribute in stream of attributes
154 * nla_find_nested() find attribute in nested attributes
155 * nla_parse() parse and validate stream of attrs
156 * nla_parse_nested() parse nested attributes
157 * nla_for_each_attr() loop over all attributes
158 * nla_for_each_nested() loop over the nested attributes
159 *=========================================================================
160 */
161
162 /**
163 * Standard attribute types to specify validation policy
164 */
165enum {
166 NLA_UNSPEC,
167 NLA_U8,
168 NLA_U16,
169 NLA_U32,
170 NLA_U64,
171 NLA_STRING,
172 NLA_FLAG,
173 NLA_MSECS,
174 NLA_NESTED,
175 NLA_NESTED_ARRAY,
176 NLA_NUL_STRING,
177 NLA_BINARY,
178 NLA_S8,
179 NLA_S16,
180 NLA_S32,
181 NLA_S64,
182 NLA_BITFIELD32,
183 NLA_REJECT,
184 NLA_EXACT_LEN,
185 NLA_EXACT_LEN_WARN,
186 __NLA_TYPE_MAX,
187};
188
189#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
190
191enum nla_policy_validation {
192 NLA_VALIDATE_NONE,
193 NLA_VALIDATE_RANGE,
194 NLA_VALIDATE_MIN,
195 NLA_VALIDATE_MAX,
196 NLA_VALIDATE_FUNCTION,
197};
198
199/**
200 * struct nla_policy - attribute validation policy
201 * @type: Type of attribute or NLA_UNSPEC
202 * @validation_type: type of attribute validation done in addition to
203 * type-specific validation (e.g. range, function call), see
204 * &enum nla_policy_validation
205 * @len: Type specific length of payload
206 *
207 * Policies are defined as arrays of this struct, the array must be
208 * accessible by attribute type up to the highest identifier to be expected.
209 *
210 * Meaning of `len' field:
211 * NLA_STRING Maximum length of string
212 * NLA_NUL_STRING Maximum length of string (excluding NUL)
213 * NLA_FLAG Unused
214 * NLA_BINARY Maximum length of attribute payload
215 * NLA_NESTED,
216 * NLA_NESTED_ARRAY Length verification is done by checking len of
217 * nested header (or empty); len field is used if
218 * validation_data is also used, for the max attr
219 * number in the nested policy.
220 * NLA_U8, NLA_U16,
221 * NLA_U32, NLA_U64,
222 * NLA_S8, NLA_S16,
223 * NLA_S32, NLA_S64,
224 * NLA_MSECS Leaving the length field zero will verify the
225 * given type fits, using it verifies minimum length
226 * just like "All other"
227 * NLA_BITFIELD32 Unused
228 * NLA_REJECT Unused
229 * NLA_EXACT_LEN Attribute must have exactly this length, otherwise
230 * it is rejected.
231 * NLA_EXACT_LEN_WARN Attribute should have exactly this length, a warning
232 * is logged if it is longer, shorter is rejected.
233 * All other Minimum length of attribute payload
234 *
235 * Meaning of `validation_data' field:
236 * NLA_BITFIELD32 This is a 32-bit bitmap/bitselector attribute and
237 * validation data must point to a u32 value of valid
238 * flags
239 * NLA_REJECT This attribute is always rejected and validation data
240 * may point to a string to report as the error instead
241 * of the generic one in extended ACK.
242 * NLA_NESTED Points to a nested policy to validate, must also set
243 * `len' to the max attribute number.
244 * Note that nla_parse() will validate, but of course not
245 * parse, the nested sub-policies.
246 * NLA_NESTED_ARRAY Points to a nested policy to validate, must also set
247 * `len' to the max attribute number. The difference to
248 * NLA_NESTED is the structure - NLA_NESTED has the
249 * nested attributes directly inside, while an array has
250 * the nested attributes at another level down and the
251 * attributes directly in the nesting don't matter.
252 * All other Unused - but note that it's a union
253 *
254 * Meaning of `min' and `max' fields, use via NLA_POLICY_MIN, NLA_POLICY_MAX
255 * and NLA_POLICY_RANGE:
256 * NLA_U8,
257 * NLA_U16,
258 * NLA_U32,
259 * NLA_U64,
260 * NLA_S8,
261 * NLA_S16,
262 * NLA_S32,
263 * NLA_S64 These are used depending on the validation_type
264 * field, if that is min/max/range then the minimum,
265 * maximum and both are used (respectively) to check
266 * the value of the integer attribute.
267 * Note that in the interest of code simplicity and
268 * struct size both limits are s16, so you cannot
269 * enforce a range that doesn't fall within the range
270 * of s16 - do that as usual in the code instead.
271 * All other Unused - but note that it's a union
272 *
273 * Meaning of `validate' field, use via NLA_POLICY_VALIDATE_FN:
274 * NLA_BINARY Validation function called for the attribute,
275 * not compatible with use of the validation_data
276 * as in NLA_BITFIELD32, NLA_REJECT, NLA_NESTED and
277 * NLA_NESTED_ARRAY.
278 * All other Unused - but note that it's a union
279 *
280 * Example:
281 * static const struct nla_policy my_policy[ATTR_MAX+1] = {
282 * [ATTR_FOO] = { .type = NLA_U16 },
283 * [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
284 * [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
285 * [ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },
286 * };
287 */
288struct nla_policy {
289 u8 type;
290 u8 validation_type;
291 u16 len;
292 union {
293 const void *validation_data;
294 struct {
295 s16 min, max;
296 };
297 int (*validate)(const struct nlattr *attr,
298 struct netlink_ext_ack *extack);
299 };
300};
301
302#define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len }
303#define NLA_POLICY_EXACT_LEN_WARN(_len) { .type = NLA_EXACT_LEN_WARN, \
304 .len = _len }
305
306#define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN)
307#define NLA_POLICY_ETH_ADDR_COMPAT NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
308
309#define _NLA_POLICY_NESTED(maxattr, policy) \
310 { .type = NLA_NESTED, .validation_data = policy, .len = maxattr }
311#define _NLA_POLICY_NESTED_ARRAY(maxattr, policy) \
312 { .type = NLA_NESTED_ARRAY, .validation_data = policy, .len = maxattr }
313#define NLA_POLICY_NESTED(policy) \
314 _NLA_POLICY_NESTED(ARRAY_SIZE(policy) - 1, policy)
315#define NLA_POLICY_NESTED_ARRAY(policy) \
316 _NLA_POLICY_NESTED_ARRAY(ARRAY_SIZE(policy) - 1, policy)
317
318#define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
319#define NLA_ENSURE_INT_TYPE(tp) \
320 (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 || \
321 tp == NLA_S16 || tp == NLA_U16 || \
322 tp == NLA_S32 || tp == NLA_U32 || \
323 tp == NLA_S64 || tp == NLA_U64) + tp)
324#define NLA_ENSURE_NO_VALIDATION_PTR(tp) \
325 (__NLA_ENSURE(tp != NLA_BITFIELD32 && \
326 tp != NLA_REJECT && \
327 tp != NLA_NESTED && \
328 tp != NLA_NESTED_ARRAY) + tp)
329
330#define NLA_POLICY_RANGE(tp, _min, _max) { \
331 .type = NLA_ENSURE_INT_TYPE(tp), \
332 .validation_type = NLA_VALIDATE_RANGE, \
333 .min = _min, \
334 .max = _max \
335}
336
337#define NLA_POLICY_MIN(tp, _min) { \
338 .type = NLA_ENSURE_INT_TYPE(tp), \
339 .validation_type = NLA_VALIDATE_MIN, \
340 .min = _min, \
341}
342
343#define NLA_POLICY_MAX(tp, _max) { \
344 .type = NLA_ENSURE_INT_TYPE(tp), \
345 .validation_type = NLA_VALIDATE_MAX, \
346 .max = _max, \
347}
348
349#define NLA_POLICY_VALIDATE_FN(tp, fn, ...) { \
350 .type = NLA_ENSURE_NO_VALIDATION_PTR(tp), \
351 .validation_type = NLA_VALIDATE_FUNCTION, \
352 .validate = fn, \
353 .len = __VA_ARGS__ + 0, \
354}
355
356/**
357 * struct nl_info - netlink source information
358 * @nlh: Netlink message header of original request
359 * @portid: Netlink PORTID of requesting application
360 */
361struct nl_info {
362 struct nlmsghdr *nlh;
363 struct net *nl_net;
364 u32 portid;
365 bool skip_notify;
366};
367
368int netlink_rcv_skb(struct sk_buff *skb,
369 int (*cb)(struct sk_buff *, struct nlmsghdr *,
370 struct netlink_ext_ack *));
371int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
372 unsigned int group, int report, gfp_t flags);
373
374int nla_validate(const struct nlattr *head, int len, int maxtype,
375 const struct nla_policy *policy,
376 struct netlink_ext_ack *extack);
377int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
378 int len, const struct nla_policy *policy,
379 struct netlink_ext_ack *extack);
380int nla_parse_strict(struct nlattr **tb, int maxtype, const struct nlattr *head,
381 int len, const struct nla_policy *policy,
382 struct netlink_ext_ack *extack);
383int nla_policy_len(const struct nla_policy *, int);
384struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
385size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
386char *nla_strdup(const struct nlattr *nla, gfp_t flags);
387int nla_memcpy(void *dest, const struct nlattr *src, int count);
388int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
389int nla_strcmp(const struct nlattr *nla, const char *str);
390struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
391struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
392 int attrlen, int padattr);
393void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
394struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
395struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
396 int attrlen, int padattr);
397void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
398void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
399 const void *data);
400void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
401 const void *data, int padattr);
402void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
403int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
404int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
405 const void *data, int padattr);
406int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
407int nla_append(struct sk_buff *skb, int attrlen, const void *data);
408
409/**************************************************************************
410 * Netlink Messages
411 **************************************************************************/
412
413/**
414 * nlmsg_msg_size - length of netlink message not including padding
415 * @payload: length of message payload
416 */
417static inline int nlmsg_msg_size(int payload)
418{
419 return NLMSG_HDRLEN + payload;
420}
421
422/**
423 * nlmsg_total_size - length of netlink message including padding
424 * @payload: length of message payload
425 */
426static inline int nlmsg_total_size(int payload)
427{
428 return NLMSG_ALIGN(nlmsg_msg_size(payload));
429}
430
431/**
432 * nlmsg_padlen - length of padding at the message's tail
433 * @payload: length of message payload
434 */
435static inline int nlmsg_padlen(int payload)
436{
437 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
438}
439
440/**
441 * nlmsg_data - head of message payload
442 * @nlh: netlink message header
443 */
444static inline void *nlmsg_data(const struct nlmsghdr *nlh)
445{
446 return (unsigned char *) nlh + NLMSG_HDRLEN;
447}
448
449/**
450 * nlmsg_len - length of message payload
451 * @nlh: netlink message header
452 */
453static inline int nlmsg_len(const struct nlmsghdr *nlh)
454{
455 return nlh->nlmsg_len - NLMSG_HDRLEN;
456}
457
458/**
459 * nlmsg_attrdata - head of attributes data
460 * @nlh: netlink message header
461 * @hdrlen: length of family specific header
462 */
463static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
464 int hdrlen)
465{
466 unsigned char *data = nlmsg_data(nlh);
467 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
468}
469
470/**
471 * nlmsg_attrlen - length of attributes data
472 * @nlh: netlink message header
473 * @hdrlen: length of family specific header
474 */
475static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
476{
477 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
478}
479
480/**
481 * nlmsg_ok - check if the netlink message fits into the remaining bytes
482 * @nlh: netlink message header
483 * @remaining: number of bytes remaining in message stream
484 */
485static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
486{
487 return (remaining >= (int) sizeof(struct nlmsghdr) &&
488 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
489 nlh->nlmsg_len <= remaining);
490}
491
492/**
493 * nlmsg_next - next netlink message in message stream
494 * @nlh: netlink message header
495 * @remaining: number of bytes remaining in message stream
496 *
497 * Returns the next netlink message in the message stream and
498 * decrements remaining by the size of the current message.
499 */
500static inline struct nlmsghdr *
501nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
502{
503 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
504
505 *remaining -= totlen;
506
507 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
508}
509
510/**
511 * nlmsg_parse - parse attributes of a netlink message
512 * @nlh: netlink message header
513 * @hdrlen: length of family specific header
514 * @tb: destination array with maxtype+1 elements
515 * @maxtype: maximum attribute type to be expected
516 * @policy: validation policy
517 * @extack: extended ACK report struct
518 *
519 * See nla_parse()
520 */
521static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
522 struct nlattr *tb[], int maxtype,
523 const struct nla_policy *policy,
524 struct netlink_ext_ack *extack)
525{
526 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
527 NL_SET_ERR_MSG(extack, "Invalid header length");
528 return -EINVAL;
529 }
530
531 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
532 nlmsg_attrlen(nlh, hdrlen), policy, extack);
533}
534
535static inline int nlmsg_parse_strict(const struct nlmsghdr *nlh, int hdrlen,
536 struct nlattr *tb[], int maxtype,
537 const struct nla_policy *policy,
538 struct netlink_ext_ack *extack)
539{
540 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
541 NL_SET_ERR_MSG(extack, "Invalid header length");
542 return -EINVAL;
543 }
544
545 return nla_parse_strict(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
546 nlmsg_attrlen(nlh, hdrlen), policy, extack);
547}
548
549/**
550 * nlmsg_find_attr - find a specific attribute in a netlink message
551 * @nlh: netlink message header
552 * @hdrlen: length of familiy specific header
553 * @attrtype: type of attribute to look for
554 *
555 * Returns the first attribute which matches the specified type.
556 */
557static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
558 int hdrlen, int attrtype)
559{
560 return nla_find(nlmsg_attrdata(nlh, hdrlen),
561 nlmsg_attrlen(nlh, hdrlen), attrtype);
562}
563
564/**
565 * nlmsg_validate - validate a netlink message including attributes
566 * @nlh: netlinket message header
567 * @hdrlen: length of familiy specific header
568 * @maxtype: maximum attribute type to be expected
569 * @policy: validation policy
570 * @extack: extended ACK report struct
571 */
572static inline int nlmsg_validate(const struct nlmsghdr *nlh,
573 int hdrlen, int maxtype,
574 const struct nla_policy *policy,
575 struct netlink_ext_ack *extack)
576{
577 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
578 return -EINVAL;
579
580 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
581 nlmsg_attrlen(nlh, hdrlen), maxtype, policy,
582 extack);
583}
584
585/**
586 * nlmsg_report - need to report back to application?
587 * @nlh: netlink message header
588 *
589 * Returns 1 if a report back to the application is requested.
590 */
591static inline int nlmsg_report(const struct nlmsghdr *nlh)
592{
593 return !!(nlh->nlmsg_flags & NLM_F_ECHO);
594}
595
596/**
597 * nlmsg_for_each_attr - iterate over a stream of attributes
598 * @pos: loop counter, set to current attribute
599 * @nlh: netlink message header
600 * @hdrlen: length of familiy specific header
601 * @rem: initialized to len, holds bytes currently remaining in stream
602 */
603#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
604 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
605 nlmsg_attrlen(nlh, hdrlen), rem)
606
607/**
608 * nlmsg_put - Add a new netlink message to an skb
609 * @skb: socket buffer to store message in
610 * @portid: netlink PORTID of requesting application
611 * @seq: sequence number of message
612 * @type: message type
613 * @payload: length of message payload
614 * @flags: message flags
615 *
616 * Returns NULL if the tailroom of the skb is insufficient to store
617 * the message header and payload.
618 */
619static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
620 int type, int payload, int flags)
621{
622 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
623 return NULL;
624
625 return __nlmsg_put(skb, portid, seq, type, payload, flags);
626}
627
628/**
629 * nlmsg_put_answer - Add a new callback based netlink message to an skb
630 * @skb: socket buffer to store message in
631 * @cb: netlink callback
632 * @type: message type
633 * @payload: length of message payload
634 * @flags: message flags
635 *
636 * Returns NULL if the tailroom of the skb is insufficient to store
637 * the message header and payload.
638 */
639static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
640 struct netlink_callback *cb,
641 int type, int payload,
642 int flags)
643{
644 return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
645 type, payload, flags);
646}
647
648/**
649 * nlmsg_new - Allocate a new netlink message
650 * @payload: size of the message payload
651 * @flags: the type of memory to allocate.
652 *
653 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
654 * and a good default is needed.
655 */
656static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
657{
658 return alloc_skb(nlmsg_total_size(payload), flags);
659}
660
661/**
662 * nlmsg_end - Finalize a netlink message
663 * @skb: socket buffer the message is stored in
664 * @nlh: netlink message header
665 *
666 * Corrects the netlink message header to include the appeneded
667 * attributes. Only necessary if attributes have been added to
668 * the message.
669 */
670static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
671{
672 nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
673}
674
675/**
676 * nlmsg_get_pos - return current position in netlink message
677 * @skb: socket buffer the message is stored in
678 *
679 * Returns a pointer to the current tail of the message.
680 */
681static inline void *nlmsg_get_pos(struct sk_buff *skb)
682{
683 return skb_tail_pointer(skb);
684}
685
686/**
687 * nlmsg_trim - Trim message to a mark
688 * @skb: socket buffer the message is stored in
689 * @mark: mark to trim to
690 *
691 * Trims the message to the provided mark.
692 */
693static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
694{
695 if (mark) {
696 WARN_ON((unsigned char *) mark < skb->data);
697 skb_trim(skb, (unsigned char *) mark - skb->data);
698 }
699}
700
701/**
702 * nlmsg_cancel - Cancel construction of a netlink message
703 * @skb: socket buffer the message is stored in
704 * @nlh: netlink message header
705 *
706 * Removes the complete netlink message including all
707 * attributes from the socket buffer again.
708 */
709static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
710{
711 nlmsg_trim(skb, nlh);
712}
713
714/**
715 * nlmsg_free - free a netlink message
716 * @skb: socket buffer of netlink message
717 */
718static inline void nlmsg_free(struct sk_buff *skb)
719{
720 kfree_skb(skb);
721}
722
723/**
724 * nlmsg_multicast - multicast a netlink message
725 * @sk: netlink socket to spread messages to
726 * @skb: netlink message as socket buffer
727 * @portid: own netlink portid to avoid sending to yourself
728 * @group: multicast group id
729 * @flags: allocation flags
730 */
731static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
732 u32 portid, unsigned int group, gfp_t flags)
733{
734 int err;
735
736 NETLINK_CB(skb).dst_group = group;
737
738 err = netlink_broadcast(sk, skb, portid, group, flags);
739 if (err > 0)
740 err = 0;
741
742 return err;
743}
744
745/**
746 * nlmsg_unicast - unicast a netlink message
747 * @sk: netlink socket to spread message to
748 * @skb: netlink message as socket buffer
749 * @portid: netlink portid of the destination socket
750 */
751static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
752{
753 int err;
754
755 err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
756 if (err > 0)
757 err = 0;
758
759 return err;
760}
761
762/**
763 * nlmsg_for_each_msg - iterate over a stream of messages
764 * @pos: loop counter, set to current message
765 * @head: head of message stream
766 * @len: length of message stream
767 * @rem: initialized to len, holds bytes currently remaining in stream
768 */
769#define nlmsg_for_each_msg(pos, head, len, rem) \
770 for (pos = head, rem = len; \
771 nlmsg_ok(pos, rem); \
772 pos = nlmsg_next(pos, &(rem)))
773
774/**
775 * nl_dump_check_consistent - check if sequence is consistent and advertise if not
776 * @cb: netlink callback structure that stores the sequence number
777 * @nlh: netlink message header to write the flag to
778 *
779 * This function checks if the sequence (generation) number changed during dump
780 * and if it did, advertises it in the netlink message header.
781 *
782 * The correct way to use it is to set cb->seq to the generation counter when
783 * all locks for dumping have been acquired, and then call this function for
784 * each message that is generated.
785 *
786 * Note that due to initialisation concerns, 0 is an invalid sequence number
787 * and must not be used by code that uses this functionality.
788 */
789static inline void
790nl_dump_check_consistent(struct netlink_callback *cb,
791 struct nlmsghdr *nlh)
792{
793 if (cb->prev_seq && cb->seq != cb->prev_seq)
794 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
795 cb->prev_seq = cb->seq;
796}
797
798/**************************************************************************
799 * Netlink Attributes
800 **************************************************************************/
801
802/**
803 * nla_attr_size - length of attribute not including padding
804 * @payload: length of payload
805 */
806static inline int nla_attr_size(int payload)
807{
808 return NLA_HDRLEN + payload;
809}
810
811/**
812 * nla_total_size - total length of attribute including padding
813 * @payload: length of payload
814 */
815static inline int nla_total_size(int payload)
816{
817 return NLA_ALIGN(nla_attr_size(payload));
818}
819
820/**
821 * nla_padlen - length of padding at the tail of attribute
822 * @payload: length of payload
823 */
824static inline int nla_padlen(int payload)
825{
826 return nla_total_size(payload) - nla_attr_size(payload);
827}
828
829/**
830 * nla_type - attribute type
831 * @nla: netlink attribute
832 */
833static inline int nla_type(const struct nlattr *nla)
834{
835 return nla->nla_type & NLA_TYPE_MASK;
836}
837
838/**
839 * nla_data - head of payload
840 * @nla: netlink attribute
841 */
842static inline void *nla_data(const struct nlattr *nla)
843{
844 return (char *) nla + NLA_HDRLEN;
845}
846
847/**
848 * nla_len - length of payload
849 * @nla: netlink attribute
850 */
851static inline int nla_len(const struct nlattr *nla)
852{
853 return nla->nla_len - NLA_HDRLEN;
854}
855
856/**
857 * nla_ok - check if the netlink attribute fits into the remaining bytes
858 * @nla: netlink attribute
859 * @remaining: number of bytes remaining in attribute stream
860 */
861static inline int nla_ok(const struct nlattr *nla, int remaining)
862{
863 return remaining >= (int) sizeof(*nla) &&
864 nla->nla_len >= sizeof(*nla) &&
865 nla->nla_len <= remaining;
866}
867
868/**
869 * nla_next - next netlink attribute in attribute stream
870 * @nla: netlink attribute
871 * @remaining: number of bytes remaining in attribute stream
872 *
873 * Returns the next netlink attribute in the attribute stream and
874 * decrements remaining by the size of the current attribute.
875 */
876static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
877{
878 unsigned int totlen = NLA_ALIGN(nla->nla_len);
879
880 *remaining -= totlen;
881 return (struct nlattr *) ((char *) nla + totlen);
882}
883
884/**
885 * nla_find_nested - find attribute in a set of nested attributes
886 * @nla: attribute containing the nested attributes
887 * @attrtype: type of attribute to look for
888 *
889 * Returns the first attribute which matches the specified type.
890 */
891static inline struct nlattr *
892nla_find_nested(const struct nlattr *nla, int attrtype)
893{
894 return nla_find(nla_data(nla), nla_len(nla), attrtype);
895}
896
897/**
898 * nla_parse_nested - parse nested attributes
899 * @tb: destination array with maxtype+1 elements
900 * @maxtype: maximum attribute type to be expected
901 * @nla: attribute containing the nested attributes
902 * @policy: validation policy
903 * @extack: extended ACK report struct
904 *
905 * See nla_parse()
906 */
907static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
908 const struct nlattr *nla,
909 const struct nla_policy *policy,
910 struct netlink_ext_ack *extack)
911{
912 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
913 extack);
914}
915
916/**
917 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
918 * @skb: socket buffer to add attribute to
919 * @attrtype: attribute type
920 * @value: numeric value
921 */
922static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
923{
924 /* temporary variables to work around GCC PR81715 with asan-stack=1 */
925 u8 tmp = value;
926
927 return nla_put(skb, attrtype, sizeof(u8), &tmp);
928}
929
930/**
931 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
932 * @skb: socket buffer to add attribute to
933 * @attrtype: attribute type
934 * @value: numeric value
935 */
936static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
937{
938 u16 tmp = value;
939
940 return nla_put(skb, attrtype, sizeof(u16), &tmp);
941}
942
943/**
944 * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
945 * @skb: socket buffer to add attribute to
946 * @attrtype: attribute type
947 * @value: numeric value
948 */
949static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
950{
951 __be16 tmp = value;
952
953 return nla_put(skb, attrtype, sizeof(__be16), &tmp);
954}
955
956/**
957 * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
958 * @skb: socket buffer to add attribute to
959 * @attrtype: attribute type
960 * @value: numeric value
961 */
962static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
963{
964 __be16 tmp = value;
965
966 return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
967}
968
969/**
970 * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
971 * @skb: socket buffer to add attribute to
972 * @attrtype: attribute type
973 * @value: numeric value
974 */
975static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
976{
977 __le16 tmp = value;
978
979 return nla_put(skb, attrtype, sizeof(__le16), &tmp);
980}
981
982/**
983 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
984 * @skb: socket buffer to add attribute to
985 * @attrtype: attribute type
986 * @value: numeric value
987 */
988static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
989{
990 u32 tmp = value;
991
992 return nla_put(skb, attrtype, sizeof(u32), &tmp);
993}
994
995/**
996 * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
997 * @skb: socket buffer to add attribute to
998 * @attrtype: attribute type
999 * @value: numeric value
1000 */
1001static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
1002{
1003 __be32 tmp = value;
1004
1005 return nla_put(skb, attrtype, sizeof(__be32), &tmp);
1006}
1007
1008/**
1009 * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1010 * @skb: socket buffer to add attribute to
1011 * @attrtype: attribute type
1012 * @value: numeric value
1013 */
1014static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
1015{
1016 __be32 tmp = value;
1017
1018 return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
1019}
1020
1021/**
1022 * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1023 * @skb: socket buffer to add attribute to
1024 * @attrtype: attribute type
1025 * @value: numeric value
1026 */
1027static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
1028{
1029 __le32 tmp = value;
1030
1031 return nla_put(skb, attrtype, sizeof(__le32), &tmp);
1032}
1033
1034/**
1035 * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1036 * @skb: socket buffer to add attribute to
1037 * @attrtype: attribute type
1038 * @value: numeric value
1039 * @padattr: attribute type for the padding
1040 */
1041static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
1042 u64 value, int padattr)
1043{
1044 u64 tmp = value;
1045
1046 return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1047}
1048
1049/**
1050 * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1051 * @skb: socket buffer to add attribute to
1052 * @attrtype: attribute type
1053 * @value: numeric value
1054 * @padattr: attribute type for the padding
1055 */
1056static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
1057 int padattr)
1058{
1059 __be64 tmp = value;
1060
1061 return nla_put_64bit(skb, attrtype, sizeof(__be64), &tmp, padattr);
1062}
1063
1064/**
1065 * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1066 * @skb: socket buffer to add attribute to
1067 * @attrtype: attribute type
1068 * @value: numeric value
1069 * @padattr: attribute type for the padding
1070 */
1071static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
1072 int padattr)
1073{
1074 __be64 tmp = value;
1075
1076 return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, tmp,
1077 padattr);
1078}
1079
1080/**
1081 * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1082 * @skb: socket buffer to add attribute to
1083 * @attrtype: attribute type
1084 * @value: numeric value
1085 * @padattr: attribute type for the padding
1086 */
1087static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
1088 int padattr)
1089{
1090 __le64 tmp = value;
1091
1092 return nla_put_64bit(skb, attrtype, sizeof(__le64), &tmp, padattr);
1093}
1094
1095/**
1096 * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1097 * @skb: socket buffer to add attribute to
1098 * @attrtype: attribute type
1099 * @value: numeric value
1100 */
1101static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
1102{
1103 s8 tmp = value;
1104
1105 return nla_put(skb, attrtype, sizeof(s8), &tmp);
1106}
1107
1108/**
1109 * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1110 * @skb: socket buffer to add attribute to
1111 * @attrtype: attribute type
1112 * @value: numeric value
1113 */
1114static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
1115{
1116 s16 tmp = value;
1117
1118 return nla_put(skb, attrtype, sizeof(s16), &tmp);
1119}
1120
1121/**
1122 * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1123 * @skb: socket buffer to add attribute to
1124 * @attrtype: attribute type
1125 * @value: numeric value
1126 */
1127static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
1128{
1129 s32 tmp = value;
1130
1131 return nla_put(skb, attrtype, sizeof(s32), &tmp);
1132}
1133
1134/**
1135 * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1136 * @skb: socket buffer to add attribute to
1137 * @attrtype: attribute type
1138 * @value: numeric value
1139 * @padattr: attribute type for the padding
1140 */
1141static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
1142 int padattr)
1143{
1144 s64 tmp = value;
1145
1146 return nla_put_64bit(skb, attrtype, sizeof(s64), &tmp, padattr);
1147}
1148
1149/**
1150 * nla_put_string - Add a string netlink attribute to a socket buffer
1151 * @skb: socket buffer to add attribute to
1152 * @attrtype: attribute type
1153 * @str: NUL terminated string
1154 */
1155static inline int nla_put_string(struct sk_buff *skb, int attrtype,
1156 const char *str)
1157{
1158 return nla_put(skb, attrtype, strlen(str) + 1, str);
1159}
1160
1161/**
1162 * nla_put_flag - Add a flag netlink attribute to a socket buffer
1163 * @skb: socket buffer to add attribute to
1164 * @attrtype: attribute type
1165 */
1166static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
1167{
1168 return nla_put(skb, attrtype, 0, NULL);
1169}
1170
1171/**
1172 * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1173 * @skb: socket buffer to add attribute to
1174 * @attrtype: attribute type
1175 * @njiffies: number of jiffies to convert to msecs
1176 * @padattr: attribute type for the padding
1177 */
1178static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
1179 unsigned long njiffies, int padattr)
1180{
1181 u64 tmp = jiffies_to_msecs(njiffies);
1182
1183 return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1184}
1185
1186/**
1187 * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1188 * buffer
1189 * @skb: socket buffer to add attribute to
1190 * @attrtype: attribute type
1191 * @addr: IPv4 address
1192 */
1193static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1194 __be32 addr)
1195{
1196 __be32 tmp = addr;
1197
1198 return nla_put_be32(skb, attrtype, tmp);
1199}
1200
1201/**
1202 * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1203 * buffer
1204 * @skb: socket buffer to add attribute to
1205 * @attrtype: attribute type
1206 * @addr: IPv6 address
1207 */
1208static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1209 const struct in6_addr *addr)
1210{
1211 return nla_put(skb, attrtype, sizeof(*addr), addr);
1212}
1213
1214/**
1215 * nla_get_u32 - return payload of u32 attribute
1216 * @nla: u32 netlink attribute
1217 */
1218static inline u32 nla_get_u32(const struct nlattr *nla)
1219{
1220 return *(u32 *) nla_data(nla);
1221}
1222
1223/**
1224 * nla_get_be32 - return payload of __be32 attribute
1225 * @nla: __be32 netlink attribute
1226 */
1227static inline __be32 nla_get_be32(const struct nlattr *nla)
1228{
1229 return *(__be32 *) nla_data(nla);
1230}
1231
1232/**
1233 * nla_get_le32 - return payload of __le32 attribute
1234 * @nla: __le32 netlink attribute
1235 */
1236static inline __le32 nla_get_le32(const struct nlattr *nla)
1237{
1238 return *(__le32 *) nla_data(nla);
1239}
1240
1241/**
1242 * nla_get_u16 - return payload of u16 attribute
1243 * @nla: u16 netlink attribute
1244 */
1245static inline u16 nla_get_u16(const struct nlattr *nla)
1246{
1247 return *(u16 *) nla_data(nla);
1248}
1249
1250/**
1251 * nla_get_be16 - return payload of __be16 attribute
1252 * @nla: __be16 netlink attribute
1253 */
1254static inline __be16 nla_get_be16(const struct nlattr *nla)
1255{
1256 return *(__be16 *) nla_data(nla);
1257}
1258
1259/**
1260 * nla_get_le16 - return payload of __le16 attribute
1261 * @nla: __le16 netlink attribute
1262 */
1263static inline __le16 nla_get_le16(const struct nlattr *nla)
1264{
1265 return *(__le16 *) nla_data(nla);
1266}
1267
1268/**
1269 * nla_get_u8 - return payload of u8 attribute
1270 * @nla: u8 netlink attribute
1271 */
1272static inline u8 nla_get_u8(const struct nlattr *nla)
1273{
1274 return *(u8 *) nla_data(nla);
1275}
1276
1277/**
1278 * nla_get_u64 - return payload of u64 attribute
1279 * @nla: u64 netlink attribute
1280 */
1281static inline u64 nla_get_u64(const struct nlattr *nla)
1282{
1283 u64 tmp;
1284
1285 nla_memcpy(&tmp, nla, sizeof(tmp));
1286
1287 return tmp;
1288}
1289
1290/**
1291 * nla_get_be64 - return payload of __be64 attribute
1292 * @nla: __be64 netlink attribute
1293 */
1294static inline __be64 nla_get_be64(const struct nlattr *nla)
1295{
1296 __be64 tmp;
1297
1298 nla_memcpy(&tmp, nla, sizeof(tmp));
1299
1300 return tmp;
1301}
1302
1303/**
1304 * nla_get_le64 - return payload of __le64 attribute
1305 * @nla: __le64 netlink attribute
1306 */
1307static inline __le64 nla_get_le64(const struct nlattr *nla)
1308{
1309 return *(__le64 *) nla_data(nla);
1310}
1311
1312/**
1313 * nla_get_s32 - return payload of s32 attribute
1314 * @nla: s32 netlink attribute
1315 */
1316static inline s32 nla_get_s32(const struct nlattr *nla)
1317{
1318 return *(s32 *) nla_data(nla);
1319}
1320
1321/**
1322 * nla_get_s16 - return payload of s16 attribute
1323 * @nla: s16 netlink attribute
1324 */
1325static inline s16 nla_get_s16(const struct nlattr *nla)
1326{
1327 return *(s16 *) nla_data(nla);
1328}
1329
1330/**
1331 * nla_get_s8 - return payload of s8 attribute
1332 * @nla: s8 netlink attribute
1333 */
1334static inline s8 nla_get_s8(const struct nlattr *nla)
1335{
1336 return *(s8 *) nla_data(nla);
1337}
1338
1339/**
1340 * nla_get_s64 - return payload of s64 attribute
1341 * @nla: s64 netlink attribute
1342 */
1343static inline s64 nla_get_s64(const struct nlattr *nla)
1344{
1345 s64 tmp;
1346
1347 nla_memcpy(&tmp, nla, sizeof(tmp));
1348
1349 return tmp;
1350}
1351
1352/**
1353 * nla_get_flag - return payload of flag attribute
1354 * @nla: flag netlink attribute
1355 */
1356static inline int nla_get_flag(const struct nlattr *nla)
1357{
1358 return !!nla;
1359}
1360
1361/**
1362 * nla_get_msecs - return payload of msecs attribute
1363 * @nla: msecs netlink attribute
1364 *
1365 * Returns the number of milliseconds in jiffies.
1366 */
1367static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1368{
1369 u64 msecs = nla_get_u64(nla);
1370
1371 return msecs_to_jiffies((unsigned long) msecs);
1372}
1373
1374/**
1375 * nla_get_in_addr - return payload of IPv4 address attribute
1376 * @nla: IPv4 address netlink attribute
1377 */
1378static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1379{
1380 return *(__be32 *) nla_data(nla);
1381}
1382
1383/**
1384 * nla_get_in6_addr - return payload of IPv6 address attribute
1385 * @nla: IPv6 address netlink attribute
1386 */
1387static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1388{
1389 struct in6_addr tmp;
1390
1391 nla_memcpy(&tmp, nla, sizeof(tmp));
1392 return tmp;
1393}
1394
1395/**
1396 * nla_get_bitfield32 - return payload of 32 bitfield attribute
1397 * @nla: nla_bitfield32 attribute
1398 */
1399static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
1400{
1401 struct nla_bitfield32 tmp;
1402
1403 nla_memcpy(&tmp, nla, sizeof(tmp));
1404 return tmp;
1405}
1406
1407/**
1408 * nla_memdup - duplicate attribute memory (kmemdup)
1409 * @src: netlink attribute to duplicate from
1410 * @gfp: GFP mask
1411 */
1412static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
1413{
1414 return kmemdup(nla_data(src), nla_len(src), gfp);
1415}
1416
1417/**
1418 * nla_nest_start - Start a new level of nested attributes
1419 * @skb: socket buffer to add attributes to
1420 * @attrtype: attribute type of container
1421 *
1422 * Returns the container attribute
1423 */
1424static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1425{
1426 struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1427
1428 if (nla_put(skb, attrtype, 0, NULL) < 0)
1429 return NULL;
1430
1431 return start;
1432}
1433
1434/**
1435 * nla_nest_end - Finalize nesting of attributes
1436 * @skb: socket buffer the attributes are stored in
1437 * @start: container attribute
1438 *
1439 * Corrects the container attribute header to include the all
1440 * appeneded attributes.
1441 *
1442 * Returns the total data length of the skb.
1443 */
1444static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1445{
1446 start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1447 return skb->len;
1448}
1449
1450/**
1451 * nla_nest_cancel - Cancel nesting of attributes
1452 * @skb: socket buffer the message is stored in
1453 * @start: container attribute
1454 *
1455 * Removes the container attribute and including all nested
1456 * attributes. Returns -EMSGSIZE
1457 */
1458static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1459{
1460 nlmsg_trim(skb, start);
1461}
1462
1463/**
1464 * nla_validate_nested - Validate a stream of nested attributes
1465 * @start: container attribute
1466 * @maxtype: maximum attribute type to be expected
1467 * @policy: validation policy
1468 * @extack: extended ACK report struct
1469 *
1470 * Validates all attributes in the nested attribute stream against the
1471 * specified policy. Attributes with a type exceeding maxtype will be
1472 * ignored. See documenation of struct nla_policy for more details.
1473 *
1474 * Returns 0 on success or a negative error code.
1475 */
1476static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1477 const struct nla_policy *policy,
1478 struct netlink_ext_ack *extack)
1479{
1480 return nla_validate(nla_data(start), nla_len(start), maxtype, policy,
1481 extack);
1482}
1483
1484/**
1485 * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1486 * @skb: socket buffer the message is stored in
1487 *
1488 * Return true if padding is needed to align the next attribute (nla_data()) to
1489 * a 64-bit aligned area.
1490 */
1491static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1492{
1493#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1494 /* The nlattr header is 4 bytes in size, that's why we test
1495 * if the skb->data _is_ aligned. A NOP attribute, plus
1496 * nlattr header for next attribute, will make nla_data()
1497 * 8-byte aligned.
1498 */
1499 if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1500 return true;
1501#endif
1502 return false;
1503}
1504
1505/**
1506 * nla_align_64bit - 64-bit align the nla_data() of next attribute
1507 * @skb: socket buffer the message is stored in
1508 * @padattr: attribute type for the padding
1509 *
1510 * Conditionally emit a padding netlink attribute in order to make
1511 * the next attribute we emit have a 64-bit aligned nla_data() area.
1512 * This will only be done in architectures which do not have
1513 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1514 *
1515 * Returns zero on success or a negative error code.
1516 */
1517static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1518{
1519 if (nla_need_padding_for_64bit(skb) &&
1520 !nla_reserve(skb, padattr, 0))
1521 return -EMSGSIZE;
1522
1523 return 0;
1524}
1525
1526/**
1527 * nla_total_size_64bit - total length of attribute including padding
1528 * @payload: length of payload
1529 */
1530static inline int nla_total_size_64bit(int payload)
1531{
1532 return NLA_ALIGN(nla_attr_size(payload))
1533#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1534 + NLA_ALIGN(nla_attr_size(0))
1535#endif
1536 ;
1537}
1538
1539/**
1540 * nla_for_each_attr - iterate over a stream of attributes
1541 * @pos: loop counter, set to current attribute
1542 * @head: head of attribute stream
1543 * @len: length of attribute stream
1544 * @rem: initialized to len, holds bytes currently remaining in stream
1545 */
1546#define nla_for_each_attr(pos, head, len, rem) \
1547 for (pos = head, rem = len; \
1548 nla_ok(pos, rem); \
1549 pos = nla_next(pos, &(rem)))
1550
1551/**
1552 * nla_for_each_nested - iterate over nested attributes
1553 * @pos: loop counter, set to current attribute
1554 * @nla: attribute containing the nested attributes
1555 * @rem: initialized to len, holds bytes currently remaining in stream
1556 */
1557#define nla_for_each_nested(pos, nla, rem) \
1558 nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1559
1560/**
1561 * nla_is_last - Test if attribute is last in stream
1562 * @nla: attribute to test
1563 * @rem: bytes remaining in stream
1564 */
1565static inline bool nla_is_last(const struct nlattr *nla, int rem)
1566{
1567 return nla->nla_len == rem;
1568}
1569
1570#endif
1571