1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_NETLINK_H
3 #define __NET_NETLINK_H
5 #include <linux/types.h>
6 #include <linux/netlink.h>
7 #include <linux/jiffies.h>
10 /* ========================================================================
11 * Netlink Messages and Attributes Interface (As Seen On TV)
12 * ------------------------------------------------------------------------
14 * ------------------------------------------------------------------------
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)-----------------------+
26 * <---------------------- nlmsg_len(nlh) --------------------->
27 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
28 * +----------------------+- - -+--------------------------------+
29 * | Family Header | Pad | Attributes |
30 * +----------------------+- - -+--------------------------------+
31 * nlmsg_attrdata(nlh, hdrlen)---^
34 * struct nlmsghdr netlink message header
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
47 * nlmsg_multicast() multicast message to several groups
48 * nlmsg_unicast() unicast a message to a single socket
49 * nlmsg_notify() send notification message
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
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
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
72 * nlmsg_report() report back to application?
74 * ------------------------------------------------------------------------
75 * Attributes Interface
76 * ------------------------------------------------------------------------
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)-----------------------------'
89 * struct nlattr netlink attribute header
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
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
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
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
126 * Attribute Payload Access:
127 * nla_data(nla) head of attribute payload
128 * nla_len(nla) length of attribute payload
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
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
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 *=========================================================================
163 * Standard attribute types to specify validation policy
189 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
191 enum nla_policy_validation {
196 NLA_VALIDATE_FUNCTION,
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
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.
210 * Meaning of `len' field:
211 * NLA_STRING Maximum length of string
212 * NLA_NUL_STRING Maximum length of string (excluding NUL)
214 * NLA_BINARY Maximum length of attribute payload
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.
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
229 * NLA_EXACT_LEN Attribute must have exactly this length, otherwise
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
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
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
254 * Meaning of `min' and `max' fields, use via NLA_POLICY_MIN, NLA_POLICY_MAX
255 * and NLA_POLICY_RANGE:
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
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
278 * All other Unused - but note that it's a union
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 },
293 const void *validation_data;
297 int (*validate)(const struct nlattr *attr,
298 struct netlink_ext_ack *extack);
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, \
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)
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 }
314 #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
315 #define NLA_ENSURE_INT_TYPE(tp) \
316 (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 || \
317 tp == NLA_S16 || tp == NLA_U16 || \
318 tp == NLA_S32 || tp == NLA_U32 || \
319 tp == NLA_S64 || tp == NLA_U64) + tp)
320 #define NLA_ENSURE_NO_VALIDATION_PTR(tp) \
321 (__NLA_ENSURE(tp != NLA_BITFIELD32 && \
322 tp != NLA_REJECT && \
323 tp != NLA_NESTED && \
324 tp != NLA_NESTED_ARRAY) + tp)
326 #define NLA_POLICY_RANGE(tp, _min, _max) { \
327 .type = NLA_ENSURE_INT_TYPE(tp), \
328 .validation_type = NLA_VALIDATE_RANGE, \
333 #define NLA_POLICY_MIN(tp, _min) { \
334 .type = NLA_ENSURE_INT_TYPE(tp), \
335 .validation_type = NLA_VALIDATE_MIN, \
339 #define NLA_POLICY_MAX(tp, _max) { \
340 .type = NLA_ENSURE_INT_TYPE(tp), \
341 .validation_type = NLA_VALIDATE_MAX, \
345 #define NLA_POLICY_VALIDATE_FN(tp, fn, ...) { \
346 .type = NLA_ENSURE_NO_VALIDATION_PTR(tp), \
347 .validation_type = NLA_VALIDATE_FUNCTION, \
349 .len = __VA_ARGS__ + 0, \
353 * struct nl_info - netlink source information
354 * @nlh: Netlink message header of original request
355 * @portid: Netlink PORTID of requesting application
358 struct nlmsghdr *nlh;
364 int netlink_rcv_skb(struct sk_buff *skb,
365 int (*cb)(struct sk_buff *, struct nlmsghdr *,
366 struct netlink_ext_ack *));
367 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
368 unsigned int group, int report, gfp_t flags);
370 int nla_validate(const struct nlattr *head, int len, int maxtype,
371 const struct nla_policy *policy,
372 struct netlink_ext_ack *extack);
373 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
374 int len, const struct nla_policy *policy,
375 struct netlink_ext_ack *extack);
376 int nla_parse_strict(struct nlattr **tb, int maxtype, const struct nlattr *head,
377 int len, const struct nla_policy *policy,
378 struct netlink_ext_ack *extack);
379 int nla_policy_len(const struct nla_policy *, int);
380 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
381 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
382 char *nla_strdup(const struct nlattr *nla, gfp_t flags);
383 int nla_memcpy(void *dest, const struct nlattr *src, int count);
384 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
385 int nla_strcmp(const struct nlattr *nla, const char *str);
386 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
387 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
388 int attrlen, int padattr);
389 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
390 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
391 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
392 int attrlen, int padattr);
393 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
394 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
396 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
397 const void *data, int padattr);
398 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
399 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
400 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
401 const void *data, int padattr);
402 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
403 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
405 /**************************************************************************
407 **************************************************************************/
410 * nlmsg_msg_size - length of netlink message not including padding
411 * @payload: length of message payload
413 static inline int nlmsg_msg_size(int payload)
415 return NLMSG_HDRLEN + payload;
419 * nlmsg_total_size - length of netlink message including padding
420 * @payload: length of message payload
422 static inline int nlmsg_total_size(int payload)
424 return NLMSG_ALIGN(nlmsg_msg_size(payload));
428 * nlmsg_padlen - length of padding at the message's tail
429 * @payload: length of message payload
431 static inline int nlmsg_padlen(int payload)
433 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
437 * nlmsg_data - head of message payload
438 * @nlh: netlink message header
440 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
442 return (unsigned char *) nlh + NLMSG_HDRLEN;
446 * nlmsg_len - length of message payload
447 * @nlh: netlink message header
449 static inline int nlmsg_len(const struct nlmsghdr *nlh)
451 return nlh->nlmsg_len - NLMSG_HDRLEN;
455 * nlmsg_attrdata - head of attributes data
456 * @nlh: netlink message header
457 * @hdrlen: length of family specific header
459 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
462 unsigned char *data = nlmsg_data(nlh);
463 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
467 * nlmsg_attrlen - length of attributes data
468 * @nlh: netlink message header
469 * @hdrlen: length of family specific header
471 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
473 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
477 * nlmsg_ok - check if the netlink message fits into the remaining bytes
478 * @nlh: netlink message header
479 * @remaining: number of bytes remaining in message stream
481 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
483 return (remaining >= (int) sizeof(struct nlmsghdr) &&
484 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
485 nlh->nlmsg_len <= remaining);
489 * nlmsg_next - next netlink message in message stream
490 * @nlh: netlink message header
491 * @remaining: number of bytes remaining in message stream
493 * Returns the next netlink message in the message stream and
494 * decrements remaining by the size of the current message.
496 static inline struct nlmsghdr *
497 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
499 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
501 *remaining -= totlen;
503 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
507 * nlmsg_parse - parse attributes of a netlink message
508 * @nlh: netlink message header
509 * @hdrlen: length of family specific header
510 * @tb: destination array with maxtype+1 elements
511 * @maxtype: maximum attribute type to be expected
512 * @policy: validation policy
513 * @extack: extended ACK report struct
517 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
518 struct nlattr *tb[], int maxtype,
519 const struct nla_policy *policy,
520 struct netlink_ext_ack *extack)
522 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
523 NL_SET_ERR_MSG(extack, "Invalid header length");
527 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
528 nlmsg_attrlen(nlh, hdrlen), policy, extack);
531 static inline int nlmsg_parse_strict(const struct nlmsghdr *nlh, int hdrlen,
532 struct nlattr *tb[], int maxtype,
533 const struct nla_policy *policy,
534 struct netlink_ext_ack *extack)
536 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
537 NL_SET_ERR_MSG(extack, "Invalid header length");
541 return nla_parse_strict(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
542 nlmsg_attrlen(nlh, hdrlen), policy, extack);
546 * nlmsg_find_attr - find a specific attribute in a netlink message
547 * @nlh: netlink message header
548 * @hdrlen: length of familiy specific header
549 * @attrtype: type of attribute to look for
551 * Returns the first attribute which matches the specified type.
553 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
554 int hdrlen, int attrtype)
556 return nla_find(nlmsg_attrdata(nlh, hdrlen),
557 nlmsg_attrlen(nlh, hdrlen), attrtype);
561 * nlmsg_validate - validate a netlink message including attributes
562 * @nlh: netlinket message header
563 * @hdrlen: length of familiy specific header
564 * @maxtype: maximum attribute type to be expected
565 * @policy: validation policy
566 * @extack: extended ACK report struct
568 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
569 int hdrlen, int maxtype,
570 const struct nla_policy *policy,
571 struct netlink_ext_ack *extack)
573 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
576 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
577 nlmsg_attrlen(nlh, hdrlen), maxtype, policy,
582 * nlmsg_report - need to report back to application?
583 * @nlh: netlink message header
585 * Returns 1 if a report back to the application is requested.
587 static inline int nlmsg_report(const struct nlmsghdr *nlh)
589 return !!(nlh->nlmsg_flags & NLM_F_ECHO);
593 * nlmsg_for_each_attr - iterate over a stream of attributes
594 * @pos: loop counter, set to current attribute
595 * @nlh: netlink message header
596 * @hdrlen: length of familiy specific header
597 * @rem: initialized to len, holds bytes currently remaining in stream
599 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
600 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
601 nlmsg_attrlen(nlh, hdrlen), rem)
604 * nlmsg_put - Add a new netlink message to an skb
605 * @skb: socket buffer to store message in
606 * @portid: netlink PORTID of requesting application
607 * @seq: sequence number of message
608 * @type: message type
609 * @payload: length of message payload
610 * @flags: message flags
612 * Returns NULL if the tailroom of the skb is insufficient to store
613 * the message header and payload.
615 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
616 int type, int payload, int flags)
618 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
621 return __nlmsg_put(skb, portid, seq, type, payload, flags);
625 * nlmsg_put_answer - Add a new callback based netlink message to an skb
626 * @skb: socket buffer to store message in
627 * @cb: netlink callback
628 * @type: message type
629 * @payload: length of message payload
630 * @flags: message flags
632 * Returns NULL if the tailroom of the skb is insufficient to store
633 * the message header and payload.
635 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
636 struct netlink_callback *cb,
637 int type, int payload,
640 return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
641 type, payload, flags);
645 * nlmsg_new - Allocate a new netlink message
646 * @payload: size of the message payload
647 * @flags: the type of memory to allocate.
649 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
650 * and a good default is needed.
652 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
654 return alloc_skb(nlmsg_total_size(payload), flags);
658 * nlmsg_end - Finalize a netlink message
659 * @skb: socket buffer the message is stored in
660 * @nlh: netlink message header
662 * Corrects the netlink message header to include the appeneded
663 * attributes. Only necessary if attributes have been added to
666 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
668 nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
672 * nlmsg_get_pos - return current position in netlink message
673 * @skb: socket buffer the message is stored in
675 * Returns a pointer to the current tail of the message.
677 static inline void *nlmsg_get_pos(struct sk_buff *skb)
679 return skb_tail_pointer(skb);
683 * nlmsg_trim - Trim message to a mark
684 * @skb: socket buffer the message is stored in
685 * @mark: mark to trim to
687 * Trims the message to the provided mark.
689 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
692 WARN_ON((unsigned char *) mark < skb->data);
693 skb_trim(skb, (unsigned char *) mark - skb->data);
698 * nlmsg_cancel - Cancel construction of a netlink message
699 * @skb: socket buffer the message is stored in
700 * @nlh: netlink message header
702 * Removes the complete netlink message including all
703 * attributes from the socket buffer again.
705 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
707 nlmsg_trim(skb, nlh);
711 * nlmsg_free - free a netlink message
712 * @skb: socket buffer of netlink message
714 static inline void nlmsg_free(struct sk_buff *skb)
720 * nlmsg_multicast - multicast a netlink message
721 * @sk: netlink socket to spread messages to
722 * @skb: netlink message as socket buffer
723 * @portid: own netlink portid to avoid sending to yourself
724 * @group: multicast group id
725 * @flags: allocation flags
727 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
728 u32 portid, unsigned int group, gfp_t flags)
732 NETLINK_CB(skb).dst_group = group;
734 err = netlink_broadcast(sk, skb, portid, group, flags);
742 * nlmsg_unicast - unicast a netlink message
743 * @sk: netlink socket to spread message to
744 * @skb: netlink message as socket buffer
745 * @portid: netlink portid of the destination socket
747 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
751 err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
759 * nlmsg_for_each_msg - iterate over a stream of messages
760 * @pos: loop counter, set to current message
761 * @head: head of message stream
762 * @len: length of message stream
763 * @rem: initialized to len, holds bytes currently remaining in stream
765 #define nlmsg_for_each_msg(pos, head, len, rem) \
766 for (pos = head, rem = len; \
767 nlmsg_ok(pos, rem); \
768 pos = nlmsg_next(pos, &(rem)))
771 * nl_dump_check_consistent - check if sequence is consistent and advertise if not
772 * @cb: netlink callback structure that stores the sequence number
773 * @nlh: netlink message header to write the flag to
775 * This function checks if the sequence (generation) number changed during dump
776 * and if it did, advertises it in the netlink message header.
778 * The correct way to use it is to set cb->seq to the generation counter when
779 * all locks for dumping have been acquired, and then call this function for
780 * each message that is generated.
782 * Note that due to initialisation concerns, 0 is an invalid sequence number
783 * and must not be used by code that uses this functionality.
786 nl_dump_check_consistent(struct netlink_callback *cb,
787 struct nlmsghdr *nlh)
789 if (cb->prev_seq && cb->seq != cb->prev_seq)
790 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
791 cb->prev_seq = cb->seq;
794 /**************************************************************************
796 **************************************************************************/
799 * nla_attr_size - length of attribute not including padding
800 * @payload: length of payload
802 static inline int nla_attr_size(int payload)
804 return NLA_HDRLEN + payload;
808 * nla_total_size - total length of attribute including padding
809 * @payload: length of payload
811 static inline int nla_total_size(int payload)
813 return NLA_ALIGN(nla_attr_size(payload));
817 * nla_padlen - length of padding at the tail of attribute
818 * @payload: length of payload
820 static inline int nla_padlen(int payload)
822 return nla_total_size(payload) - nla_attr_size(payload);
826 * nla_type - attribute type
827 * @nla: netlink attribute
829 static inline int nla_type(const struct nlattr *nla)
831 return nla->nla_type & NLA_TYPE_MASK;
835 * nla_data - head of payload
836 * @nla: netlink attribute
838 static inline void *nla_data(const struct nlattr *nla)
840 return (char *) nla + NLA_HDRLEN;
844 * nla_len - length of payload
845 * @nla: netlink attribute
847 static inline int nla_len(const struct nlattr *nla)
849 return nla->nla_len - NLA_HDRLEN;
853 * nla_ok - check if the netlink attribute fits into the remaining bytes
854 * @nla: netlink attribute
855 * @remaining: number of bytes remaining in attribute stream
857 static inline int nla_ok(const struct nlattr *nla, int remaining)
859 return remaining >= (int) sizeof(*nla) &&
860 nla->nla_len >= sizeof(*nla) &&
861 nla->nla_len <= remaining;
865 * nla_next - next netlink attribute in attribute stream
866 * @nla: netlink attribute
867 * @remaining: number of bytes remaining in attribute stream
869 * Returns the next netlink attribute in the attribute stream and
870 * decrements remaining by the size of the current attribute.
872 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
874 unsigned int totlen = NLA_ALIGN(nla->nla_len);
876 *remaining -= totlen;
877 return (struct nlattr *) ((char *) nla + totlen);
881 * nla_find_nested - find attribute in a set of nested attributes
882 * @nla: attribute containing the nested attributes
883 * @attrtype: type of attribute to look for
885 * Returns the first attribute which matches the specified type.
887 static inline struct nlattr *
888 nla_find_nested(const struct nlattr *nla, int attrtype)
890 return nla_find(nla_data(nla), nla_len(nla), attrtype);
894 * nla_parse_nested - parse nested attributes
895 * @tb: destination array with maxtype+1 elements
896 * @maxtype: maximum attribute type to be expected
897 * @nla: attribute containing the nested attributes
898 * @policy: validation policy
899 * @extack: extended ACK report struct
903 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
904 const struct nlattr *nla,
905 const struct nla_policy *policy,
906 struct netlink_ext_ack *extack)
908 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
913 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
914 * @skb: socket buffer to add attribute to
915 * @attrtype: attribute type
916 * @value: numeric value
918 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
920 /* temporary variables to work around GCC PR81715 with asan-stack=1 */
923 return nla_put(skb, attrtype, sizeof(u8), &tmp);
927 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
928 * @skb: socket buffer to add attribute to
929 * @attrtype: attribute type
930 * @value: numeric value
932 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
936 return nla_put(skb, attrtype, sizeof(u16), &tmp);
940 * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
941 * @skb: socket buffer to add attribute to
942 * @attrtype: attribute type
943 * @value: numeric value
945 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
949 return nla_put(skb, attrtype, sizeof(__be16), &tmp);
953 * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
954 * @skb: socket buffer to add attribute to
955 * @attrtype: attribute type
956 * @value: numeric value
958 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
962 return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
966 * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
967 * @skb: socket buffer to add attribute to
968 * @attrtype: attribute type
969 * @value: numeric value
971 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
975 return nla_put(skb, attrtype, sizeof(__le16), &tmp);
979 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
980 * @skb: socket buffer to add attribute to
981 * @attrtype: attribute type
982 * @value: numeric value
984 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
988 return nla_put(skb, attrtype, sizeof(u32), &tmp);
992 * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
993 * @skb: socket buffer to add attribute to
994 * @attrtype: attribute type
995 * @value: numeric value
997 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
1001 return nla_put(skb, attrtype, sizeof(__be32), &tmp);
1005 * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1006 * @skb: socket buffer to add attribute to
1007 * @attrtype: attribute type
1008 * @value: numeric value
1010 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
1014 return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
1018 * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1019 * @skb: socket buffer to add attribute to
1020 * @attrtype: attribute type
1021 * @value: numeric value
1023 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
1027 return nla_put(skb, attrtype, sizeof(__le32), &tmp);
1031 * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1032 * @skb: socket buffer to add attribute to
1033 * @attrtype: attribute type
1034 * @value: numeric value
1035 * @padattr: attribute type for the padding
1037 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
1038 u64 value, int padattr)
1042 return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1046 * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1047 * @skb: socket buffer to add attribute to
1048 * @attrtype: attribute type
1049 * @value: numeric value
1050 * @padattr: attribute type for the padding
1052 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
1057 return nla_put_64bit(skb, attrtype, sizeof(__be64), &tmp, padattr);
1061 * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1062 * @skb: socket buffer to add attribute to
1063 * @attrtype: attribute type
1064 * @value: numeric value
1065 * @padattr: attribute type for the padding
1067 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
1072 return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, tmp,
1077 * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1078 * @skb: socket buffer to add attribute to
1079 * @attrtype: attribute type
1080 * @value: numeric value
1081 * @padattr: attribute type for the padding
1083 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
1088 return nla_put_64bit(skb, attrtype, sizeof(__le64), &tmp, padattr);
1092 * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1093 * @skb: socket buffer to add attribute to
1094 * @attrtype: attribute type
1095 * @value: numeric value
1097 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
1101 return nla_put(skb, attrtype, sizeof(s8), &tmp);
1105 * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1106 * @skb: socket buffer to add attribute to
1107 * @attrtype: attribute type
1108 * @value: numeric value
1110 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
1114 return nla_put(skb, attrtype, sizeof(s16), &tmp);
1118 * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1119 * @skb: socket buffer to add attribute to
1120 * @attrtype: attribute type
1121 * @value: numeric value
1123 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
1127 return nla_put(skb, attrtype, sizeof(s32), &tmp);
1131 * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1132 * @skb: socket buffer to add attribute to
1133 * @attrtype: attribute type
1134 * @value: numeric value
1135 * @padattr: attribute type for the padding
1137 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
1142 return nla_put_64bit(skb, attrtype, sizeof(s64), &tmp, padattr);
1146 * nla_put_string - Add a string netlink attribute to a socket buffer
1147 * @skb: socket buffer to add attribute to
1148 * @attrtype: attribute type
1149 * @str: NUL terminated string
1151 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
1154 return nla_put(skb, attrtype, strlen(str) + 1, str);
1158 * nla_put_flag - Add a flag netlink attribute to a socket buffer
1159 * @skb: socket buffer to add attribute to
1160 * @attrtype: attribute type
1162 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
1164 return nla_put(skb, attrtype, 0, NULL);
1168 * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1169 * @skb: socket buffer to add attribute to
1170 * @attrtype: attribute type
1171 * @njiffies: number of jiffies to convert to msecs
1172 * @padattr: attribute type for the padding
1174 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
1175 unsigned long njiffies, int padattr)
1177 u64 tmp = jiffies_to_msecs(njiffies);
1179 return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1183 * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1185 * @skb: socket buffer to add attribute to
1186 * @attrtype: attribute type
1187 * @addr: IPv4 address
1189 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1194 return nla_put_be32(skb, attrtype, tmp);
1198 * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1200 * @skb: socket buffer to add attribute to
1201 * @attrtype: attribute type
1202 * @addr: IPv6 address
1204 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1205 const struct in6_addr *addr)
1207 return nla_put(skb, attrtype, sizeof(*addr), addr);
1211 * nla_get_u32 - return payload of u32 attribute
1212 * @nla: u32 netlink attribute
1214 static inline u32 nla_get_u32(const struct nlattr *nla)
1216 return *(u32 *) nla_data(nla);
1220 * nla_get_be32 - return payload of __be32 attribute
1221 * @nla: __be32 netlink attribute
1223 static inline __be32 nla_get_be32(const struct nlattr *nla)
1225 return *(__be32 *) nla_data(nla);
1229 * nla_get_le32 - return payload of __le32 attribute
1230 * @nla: __le32 netlink attribute
1232 static inline __le32 nla_get_le32(const struct nlattr *nla)
1234 return *(__le32 *) nla_data(nla);
1238 * nla_get_u16 - return payload of u16 attribute
1239 * @nla: u16 netlink attribute
1241 static inline u16 nla_get_u16(const struct nlattr *nla)
1243 return *(u16 *) nla_data(nla);
1247 * nla_get_be16 - return payload of __be16 attribute
1248 * @nla: __be16 netlink attribute
1250 static inline __be16 nla_get_be16(const struct nlattr *nla)
1252 return *(__be16 *) nla_data(nla);
1256 * nla_get_le16 - return payload of __le16 attribute
1257 * @nla: __le16 netlink attribute
1259 static inline __le16 nla_get_le16(const struct nlattr *nla)
1261 return *(__le16 *) nla_data(nla);
1265 * nla_get_u8 - return payload of u8 attribute
1266 * @nla: u8 netlink attribute
1268 static inline u8 nla_get_u8(const struct nlattr *nla)
1270 return *(u8 *) nla_data(nla);
1274 * nla_get_u64 - return payload of u64 attribute
1275 * @nla: u64 netlink attribute
1277 static inline u64 nla_get_u64(const struct nlattr *nla)
1281 nla_memcpy(&tmp, nla, sizeof(tmp));
1287 * nla_get_be64 - return payload of __be64 attribute
1288 * @nla: __be64 netlink attribute
1290 static inline __be64 nla_get_be64(const struct nlattr *nla)
1294 nla_memcpy(&tmp, nla, sizeof(tmp));
1300 * nla_get_le64 - return payload of __le64 attribute
1301 * @nla: __le64 netlink attribute
1303 static inline __le64 nla_get_le64(const struct nlattr *nla)
1305 return *(__le64 *) nla_data(nla);
1309 * nla_get_s32 - return payload of s32 attribute
1310 * @nla: s32 netlink attribute
1312 static inline s32 nla_get_s32(const struct nlattr *nla)
1314 return *(s32 *) nla_data(nla);
1318 * nla_get_s16 - return payload of s16 attribute
1319 * @nla: s16 netlink attribute
1321 static inline s16 nla_get_s16(const struct nlattr *nla)
1323 return *(s16 *) nla_data(nla);
1327 * nla_get_s8 - return payload of s8 attribute
1328 * @nla: s8 netlink attribute
1330 static inline s8 nla_get_s8(const struct nlattr *nla)
1332 return *(s8 *) nla_data(nla);
1336 * nla_get_s64 - return payload of s64 attribute
1337 * @nla: s64 netlink attribute
1339 static inline s64 nla_get_s64(const struct nlattr *nla)
1343 nla_memcpy(&tmp, nla, sizeof(tmp));
1349 * nla_get_flag - return payload of flag attribute
1350 * @nla: flag netlink attribute
1352 static inline int nla_get_flag(const struct nlattr *nla)
1358 * nla_get_msecs - return payload of msecs attribute
1359 * @nla: msecs netlink attribute
1361 * Returns the number of milliseconds in jiffies.
1363 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1365 u64 msecs = nla_get_u64(nla);
1367 return msecs_to_jiffies((unsigned long) msecs);
1371 * nla_get_in_addr - return payload of IPv4 address attribute
1372 * @nla: IPv4 address netlink attribute
1374 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1376 return *(__be32 *) nla_data(nla);
1380 * nla_get_in6_addr - return payload of IPv6 address attribute
1381 * @nla: IPv6 address netlink attribute
1383 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1385 struct in6_addr tmp;
1387 nla_memcpy(&tmp, nla, sizeof(tmp));
1392 * nla_get_bitfield32 - return payload of 32 bitfield attribute
1393 * @nla: nla_bitfield32 attribute
1395 static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
1397 struct nla_bitfield32 tmp;
1399 nla_memcpy(&tmp, nla, sizeof(tmp));
1404 * nla_memdup - duplicate attribute memory (kmemdup)
1405 * @src: netlink attribute to duplicate from
1408 static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
1410 return kmemdup(nla_data(src), nla_len(src), gfp);
1414 * nla_nest_start - Start a new level of nested attributes
1415 * @skb: socket buffer to add attributes to
1416 * @attrtype: attribute type of container
1418 * Returns the container attribute
1420 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1422 struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1424 if (nla_put(skb, attrtype, 0, NULL) < 0)
1431 * nla_nest_end - Finalize nesting of attributes
1432 * @skb: socket buffer the attributes are stored in
1433 * @start: container attribute
1435 * Corrects the container attribute header to include the all
1436 * appeneded attributes.
1438 * Returns the total data length of the skb.
1440 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1442 start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1447 * nla_nest_cancel - Cancel nesting of attributes
1448 * @skb: socket buffer the message is stored in
1449 * @start: container attribute
1451 * Removes the container attribute and including all nested
1452 * attributes. Returns -EMSGSIZE
1454 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1456 nlmsg_trim(skb, start);
1460 * nla_validate_nested - Validate a stream of nested attributes
1461 * @start: container attribute
1462 * @maxtype: maximum attribute type to be expected
1463 * @policy: validation policy
1464 * @extack: extended ACK report struct
1466 * Validates all attributes in the nested attribute stream against the
1467 * specified policy. Attributes with a type exceeding maxtype will be
1468 * ignored. See documenation of struct nla_policy for more details.
1470 * Returns 0 on success or a negative error code.
1472 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1473 const struct nla_policy *policy,
1474 struct netlink_ext_ack *extack)
1476 return nla_validate(nla_data(start), nla_len(start), maxtype, policy,
1481 * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1482 * @skb: socket buffer the message is stored in
1484 * Return true if padding is needed to align the next attribute (nla_data()) to
1485 * a 64-bit aligned area.
1487 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1489 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1490 /* The nlattr header is 4 bytes in size, that's why we test
1491 * if the skb->data _is_ aligned. A NOP attribute, plus
1492 * nlattr header for next attribute, will make nla_data()
1495 if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1502 * nla_align_64bit - 64-bit align the nla_data() of next attribute
1503 * @skb: socket buffer the message is stored in
1504 * @padattr: attribute type for the padding
1506 * Conditionally emit a padding netlink attribute in order to make
1507 * the next attribute we emit have a 64-bit aligned nla_data() area.
1508 * This will only be done in architectures which do not have
1509 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1511 * Returns zero on success or a negative error code.
1513 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1515 if (nla_need_padding_for_64bit(skb) &&
1516 !nla_reserve(skb, padattr, 0))
1523 * nla_total_size_64bit - total length of attribute including padding
1524 * @payload: length of payload
1526 static inline int nla_total_size_64bit(int payload)
1528 return NLA_ALIGN(nla_attr_size(payload))
1529 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1530 + NLA_ALIGN(nla_attr_size(0))
1536 * nla_for_each_attr - iterate over a stream of attributes
1537 * @pos: loop counter, set to current attribute
1538 * @head: head of attribute stream
1539 * @len: length of attribute stream
1540 * @rem: initialized to len, holds bytes currently remaining in stream
1542 #define nla_for_each_attr(pos, head, len, rem) \
1543 for (pos = head, rem = len; \
1545 pos = nla_next(pos, &(rem)))
1548 * nla_for_each_nested - iterate over nested attributes
1549 * @pos: loop counter, set to current attribute
1550 * @nla: attribute containing the nested attributes
1551 * @rem: initialized to len, holds bytes currently remaining in stream
1553 #define nla_for_each_nested(pos, nla, rem) \
1554 nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1557 * nla_is_last - Test if attribute is last in stream
1558 * @nla: attribute to test
1559 * @rem: bytes remaining in stream
1561 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1563 return nla->nla_len == rem;