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1#ifndef __NET_NETLINK_H
2#define __NET_NETLINK_H
3
4#include <linux/types.h>
5#include <linux/netlink.h>
6#include <linux/jiffies.h>
7
8/* ========================================================================
9 * Netlink Messages and Attributes Interface (As Seen On TV)
10 * ------------------------------------------------------------------------
11 * Messages Interface
12 * ------------------------------------------------------------------------
13 *
14 * Message Format:
15 * <--- nlmsg_total_size(payload) --->
16 * <-- nlmsg_msg_size(payload) ->
17 * +----------+- - -+-------------+- - -+-------- - -
18 * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
19 * +----------+- - -+-------------+- - -+-------- - -
20 * nlmsg_data(nlh)---^ ^
21 * nlmsg_next(nlh)-----------------------+
22 *
23 * Payload Format:
24 * <---------------------- nlmsg_len(nlh) --------------------->
25 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
26 * +----------------------+- - -+--------------------------------+
27 * | Family Header | Pad | Attributes |
28 * +----------------------+- - -+--------------------------------+
29 * nlmsg_attrdata(nlh, hdrlen)---^
30 *
31 * Data Structures:
32 * struct nlmsghdr netlink message header
33 *
34 * Message Construction:
35 * nlmsg_new() create a new netlink message
36 * nlmsg_put() add a netlink message to an skb
37 * nlmsg_put_answer() callback based nlmsg_put()
38 * nlmsg_end() finalize netlink message
39 * nlmsg_get_pos() return current position in message
40 * nlmsg_trim() trim part of message
41 * nlmsg_cancel() cancel message construction
42 * nlmsg_free() free a netlink message
43 *
44 * Message Sending:
45 * nlmsg_multicast() multicast message to several groups
46 * nlmsg_unicast() unicast a message to a single socket
47 * nlmsg_notify() send notification message
48 *
49 * Message Length Calculations:
50 * nlmsg_msg_size(payload) length of message w/o padding
51 * nlmsg_total_size(payload) length of message w/ padding
52 * nlmsg_padlen(payload) length of padding at tail
53 *
54 * Message Payload Access:
55 * nlmsg_data(nlh) head of message payload
56 * nlmsg_len(nlh) length of message payload
57 * nlmsg_attrdata(nlh, hdrlen) head of attributes data
58 * nlmsg_attrlen(nlh, hdrlen) length of attributes data
59 *
60 * Message Parsing:
61 * nlmsg_ok(nlh, remaining) does nlh fit into remaining bytes?
62 * nlmsg_next(nlh, remaining) get next netlink message
63 * nlmsg_parse() parse attributes of a message
64 * nlmsg_find_attr() find an attribute in a message
65 * nlmsg_for_each_msg() loop over all messages
66 * nlmsg_validate() validate netlink message incl. attrs
67 * nlmsg_for_each_attr() loop over all attributes
68 *
69 * Misc:
70 * nlmsg_report() report back to application?
71 *
72 * ------------------------------------------------------------------------
73 * Attributes Interface
74 * ------------------------------------------------------------------------
75 *
76 * Attribute Format:
77 * <------- nla_total_size(payload) ------->
78 * <---- nla_attr_size(payload) ----->
79 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
80 * | Header | Pad | Payload | Pad | Header
81 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
82 * <- nla_len(nla) -> ^
83 * nla_data(nla)----^ |
84 * nla_next(nla)-----------------------------'
85 *
86 * Data Structures:
87 * struct nlattr netlink attribute header
88 *
89 * Attribute Construction:
90 * nla_reserve(skb, type, len) reserve room for an attribute
91 * nla_reserve_nohdr(skb, len) reserve room for an attribute w/o hdr
92 * nla_put(skb, type, len, data) add attribute to skb
93 * nla_put_nohdr(skb, len, data) add attribute w/o hdr
94 * nla_append(skb, len, data) append data to skb
95 *
96 * Attribute Construction for Basic Types:
97 * nla_put_u8(skb, type, value) add u8 attribute to skb
98 * nla_put_u16(skb, type, value) add u16 attribute to skb
99 * nla_put_u32(skb, type, value) add u32 attribute to skb
100 * nla_put_u64(skb, type, value) add u64 attribute to skb
101 * nla_put_string(skb, type, str) add string attribute to skb
102 * nla_put_flag(skb, type) add flag attribute to skb
103 * nla_put_msecs(skb, type, jiffies) add msecs attribute to skb
104 *
105 * Exceptions Based Attribute Construction:
106 * NLA_PUT(skb, type, len, data) add attribute to skb
107 * NLA_PUT_U8(skb, type, value) add u8 attribute to skb
108 * NLA_PUT_U16(skb, type, value) add u16 attribute to skb
109 * NLA_PUT_U32(skb, type, value) add u32 attribute to skb
110 * NLA_PUT_U64(skb, type, value) add u64 attribute to skb
111 * NLA_PUT_STRING(skb, type, str) add string attribute to skb
112 * NLA_PUT_FLAG(skb, type) add flag attribute to skb
113 * NLA_PUT_MSECS(skb, type, jiffies) add msecs attribute to skb
114 *
115 * The meaning of these functions is equal to their lower case
116 * variants but they jump to the label nla_put_failure in case
117 * of a failure.
118 *
119 * Nested Attributes Construction:
120 * nla_nest_start(skb, type) start a nested attribute
121 * nla_nest_end(skb, nla) finalize a nested attribute
122 * nla_nest_cancel(skb, nla) cancel nested attribute construction
123 *
124 * Attribute Length Calculations:
125 * nla_attr_size(payload) length of attribute w/o padding
126 * nla_total_size(payload) length of attribute w/ padding
127 * nla_padlen(payload) length of padding
128 *
129 * Attribute Payload Access:
130 * nla_data(nla) head of attribute payload
131 * nla_len(nla) length of attribute payload
132 *
133 * Attribute Payload Access for Basic Types:
134 * nla_get_u8(nla) get payload for a u8 attribute
135 * nla_get_u16(nla) get payload for a u16 attribute
136 * nla_get_u32(nla) get payload for a u32 attribute
137 * nla_get_u64(nla) get payload for a u64 attribute
138 * nla_get_flag(nla) return 1 if flag is true
139 * nla_get_msecs(nla) get payload for a msecs attribute
140 *
141 * Attribute Misc:
142 * nla_memcpy(dest, nla, count) copy attribute into memory
143 * nla_memcmp(nla, data, size) compare attribute with memory area
144 * nla_strlcpy(dst, nla, size) copy attribute to a sized string
145 * nla_strcmp(nla, str) compare attribute with string
146 *
147 * Attribute Parsing:
148 * nla_ok(nla, remaining) does nla fit into remaining bytes?
149 * nla_next(nla, remaining) get next netlink attribute
150 * nla_validate() validate a stream of attributes
151 * nla_validate_nested() validate a stream of nested attributes
152 * nla_find() find attribute in stream of attributes
153 * nla_find_nested() find attribute in nested attributes
154 * nla_parse() parse and validate stream of attrs
155 * nla_parse_nested() parse nested attribuets
156 * nla_for_each_attr() loop over all attributes
157 * nla_for_each_nested() loop over the nested attributes
158 *=========================================================================
159 */
160
161 /**
162 * Standard attribute types to specify validation policy
163 */
164enum {
165 NLA_UNSPEC,
166 NLA_U8,
167 NLA_U16,
168 NLA_U32,
169 NLA_U64,
170 NLA_STRING,
171 NLA_FLAG,
172 NLA_MSECS,
173 NLA_NESTED,
174 NLA_NESTED_COMPAT,
175 NLA_NUL_STRING,
176 NLA_BINARY,
177 __NLA_TYPE_MAX,
178};
179
180#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
181
182/**
183 * struct nla_policy - attribute validation policy
184 * @type: Type of attribute or NLA_UNSPEC
185 * @len: Type specific length of payload
186 *
187 * Policies are defined as arrays of this struct, the array must be
188 * accessible by attribute type up to the highest identifier to be expected.
189 *
190 * Meaning of `len' field:
191 * NLA_STRING Maximum length of string
192 * NLA_NUL_STRING Maximum length of string (excluding NUL)
193 * NLA_FLAG Unused
194 * NLA_BINARY Maximum length of attribute payload
195 * NLA_NESTED_COMPAT Exact length of structure payload
196 * All other Exact length of attribute payload
197 *
198 * Example:
199 * static const struct nla_policy my_policy[ATTR_MAX+1] = {
200 * [ATTR_FOO] = { .type = NLA_U16 },
201 * [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
202 * [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
203 * };
204 */
205struct nla_policy {
206 u16 type;
207 u16 len;
208};
209
210/**
211 * struct nl_info - netlink source information
212 * @nlh: Netlink message header of original request
213 * @pid: Netlink PID of requesting application
214 */
215struct nl_info {
216 struct nlmsghdr *nlh;
217 struct net *nl_net;
218 u32 pid;
219};
220
221extern int netlink_rcv_skb(struct sk_buff *skb,
222 int (*cb)(struct sk_buff *,
223 struct nlmsghdr *));
224extern int nlmsg_notify(struct sock *sk, struct sk_buff *skb,
225 u32 pid, unsigned int group, int report,
226 gfp_t flags);
227
228extern int nla_validate(const struct nlattr *head,
229 int len, int maxtype,
230 const struct nla_policy *policy);
231extern int nla_parse(struct nlattr **tb, int maxtype,
232 const struct nlattr *head, int len,
233 const struct nla_policy *policy);
234extern int nla_policy_len(const struct nla_policy *, int);
235extern struct nlattr * nla_find(const struct nlattr *head,
236 int len, int attrtype);
237extern size_t nla_strlcpy(char *dst, const struct nlattr *nla,
238 size_t dstsize);
239extern int nla_memcpy(void *dest, const struct nlattr *src, int count);
240extern int nla_memcmp(const struct nlattr *nla, const void *data,
241 size_t size);
242extern int nla_strcmp(const struct nlattr *nla, const char *str);
243extern struct nlattr * __nla_reserve(struct sk_buff *skb, int attrtype,
244 int attrlen);
245extern void * __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
246extern struct nlattr * nla_reserve(struct sk_buff *skb, int attrtype,
247 int attrlen);
248extern void * nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
249extern void __nla_put(struct sk_buff *skb, int attrtype,
250 int attrlen, const void *data);
251extern void __nla_put_nohdr(struct sk_buff *skb, int attrlen,
252 const void *data);
253extern int nla_put(struct sk_buff *skb, int attrtype,
254 int attrlen, const void *data);
255extern int nla_put_nohdr(struct sk_buff *skb, int attrlen,
256 const void *data);
257extern int nla_append(struct sk_buff *skb, int attrlen,
258 const void *data);
259
260/**************************************************************************
261 * Netlink Messages
262 **************************************************************************/
263
264/**
265 * nlmsg_msg_size - length of netlink message not including padding
266 * @payload: length of message payload
267 */
268static inline int nlmsg_msg_size(int payload)
269{
270 return NLMSG_HDRLEN + payload;
271}
272
273/**
274 * nlmsg_total_size - length of netlink message including padding
275 * @payload: length of message payload
276 */
277static inline int nlmsg_total_size(int payload)
278{
279 return NLMSG_ALIGN(nlmsg_msg_size(payload));
280}
281
282/**
283 * nlmsg_padlen - length of padding at the message's tail
284 * @payload: length of message payload
285 */
286static inline int nlmsg_padlen(int payload)
287{
288 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
289}
290
291/**
292 * nlmsg_data - head of message payload
293 * @nlh: netlink message header
294 */
295static inline void *nlmsg_data(const struct nlmsghdr *nlh)
296{
297 return (unsigned char *) nlh + NLMSG_HDRLEN;
298}
299
300/**
301 * nlmsg_len - length of message payload
302 * @nlh: netlink message header
303 */
304static inline int nlmsg_len(const struct nlmsghdr *nlh)
305{
306 return nlh->nlmsg_len - NLMSG_HDRLEN;
307}
308
309/**
310 * nlmsg_attrdata - head of attributes data
311 * @nlh: netlink message header
312 * @hdrlen: length of family specific header
313 */
314static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
315 int hdrlen)
316{
317 unsigned char *data = nlmsg_data(nlh);
318 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
319}
320
321/**
322 * nlmsg_attrlen - length of attributes data
323 * @nlh: netlink message header
324 * @hdrlen: length of family specific header
325 */
326static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
327{
328 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
329}
330
331/**
332 * nlmsg_ok - check if the netlink message fits into the remaining bytes
333 * @nlh: netlink message header
334 * @remaining: number of bytes remaining in message stream
335 */
336static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
337{
338 return (remaining >= (int) sizeof(struct nlmsghdr) &&
339 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
340 nlh->nlmsg_len <= remaining);
341}
342
343/**
344 * nlmsg_next - next netlink message in message stream
345 * @nlh: netlink message header
346 * @remaining: number of bytes remaining in message stream
347 *
348 * Returns the next netlink message in the message stream and
349 * decrements remaining by the size of the current message.
350 */
351static inline struct nlmsghdr *
352nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
353{
354 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
355
356 *remaining -= totlen;
357
358 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
359}
360
361/**
362 * nlmsg_parse - parse attributes of a netlink message
363 * @nlh: netlink message header
364 * @hdrlen: length of family specific header
365 * @tb: destination array with maxtype+1 elements
366 * @maxtype: maximum attribute type to be expected
367 * @policy: validation policy
368 *
369 * See nla_parse()
370 */
371static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
372 struct nlattr *tb[], int maxtype,
373 const struct nla_policy *policy)
374{
375 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
376 return -EINVAL;
377
378 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
379 nlmsg_attrlen(nlh, hdrlen), policy);
380}
381
382/**
383 * nlmsg_find_attr - find a specific attribute in a netlink message
384 * @nlh: netlink message header
385 * @hdrlen: length of familiy specific header
386 * @attrtype: type of attribute to look for
387 *
388 * Returns the first attribute which matches the specified type.
389 */
390static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
391 int hdrlen, int attrtype)
392{
393 return nla_find(nlmsg_attrdata(nlh, hdrlen),
394 nlmsg_attrlen(nlh, hdrlen), attrtype);
395}
396
397/**
398 * nlmsg_validate - validate a netlink message including attributes
399 * @nlh: netlinket message header
400 * @hdrlen: length of familiy specific header
401 * @maxtype: maximum attribute type to be expected
402 * @policy: validation policy
403 */
404static inline int nlmsg_validate(const struct nlmsghdr *nlh,
405 int hdrlen, int maxtype,
406 const struct nla_policy *policy)
407{
408 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
409 return -EINVAL;
410
411 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
412 nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
413}
414
415/**
416 * nlmsg_report - need to report back to application?
417 * @nlh: netlink message header
418 *
419 * Returns 1 if a report back to the application is requested.
420 */
421static inline int nlmsg_report(const struct nlmsghdr *nlh)
422{
423 return !!(nlh->nlmsg_flags & NLM_F_ECHO);
424}
425
426/**
427 * nlmsg_for_each_attr - iterate over a stream of attributes
428 * @pos: loop counter, set to current attribute
429 * @nlh: netlink message header
430 * @hdrlen: length of familiy specific header
431 * @rem: initialized to len, holds bytes currently remaining in stream
432 */
433#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
434 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
435 nlmsg_attrlen(nlh, hdrlen), rem)
436
437#if 0
438/* FIXME: Enable once all users have been converted */
439
440/**
441 * __nlmsg_put - Add a new netlink message to an skb
442 * @skb: socket buffer to store message in
443 * @pid: netlink process id
444 * @seq: sequence number of message
445 * @type: message type
446 * @payload: length of message payload
447 * @flags: message flags
448 *
449 * The caller is responsible to ensure that the skb provides enough
450 * tailroom for both the netlink header and payload.
451 */
452static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
453 u32 seq, int type, int payload,
454 int flags)
455{
456 struct nlmsghdr *nlh;
457
458 nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
459 nlh->nlmsg_type = type;
460 nlh->nlmsg_len = nlmsg_msg_size(payload);
461 nlh->nlmsg_flags = flags;
462 nlh->nlmsg_pid = pid;
463 nlh->nlmsg_seq = seq;
464
465 memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
466 nlmsg_padlen(payload));
467
468 return nlh;
469}
470#endif
471
472/**
473 * nlmsg_put - Add a new netlink message to an skb
474 * @skb: socket buffer to store message in
475 * @pid: netlink process id
476 * @seq: sequence number of message
477 * @type: message type
478 * @payload: length of message payload
479 * @flags: message flags
480 *
481 * Returns NULL if the tailroom of the skb is insufficient to store
482 * the message header and payload.
483 */
484static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
485 int type, int payload, int flags)
486{
487 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
488 return NULL;
489
490 return __nlmsg_put(skb, pid, seq, type, payload, flags);
491}
492
493/**
494 * nlmsg_put_answer - Add a new callback based netlink message to an skb
495 * @skb: socket buffer to store message in
496 * @cb: netlink callback
497 * @type: message type
498 * @payload: length of message payload
499 * @flags: message flags
500 *
501 * Returns NULL if the tailroom of the skb is insufficient to store
502 * the message header and payload.
503 */
504static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
505 struct netlink_callback *cb,
506 int type, int payload,
507 int flags)
508{
509 return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
510 type, payload, flags);
511}
512
513/**
514 * nlmsg_new - Allocate a new netlink message
515 * @payload: size of the message payload
516 * @flags: the type of memory to allocate.
517 *
518 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
519 * and a good default is needed.
520 */
521static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
522{
523 return alloc_skb(nlmsg_total_size(payload), flags);
524}
525
526/**
527 * nlmsg_end - Finalize a netlink message
528 * @skb: socket buffer the message is stored in
529 * @nlh: netlink message header
530 *
531 * Corrects the netlink message header to include the appeneded
532 * attributes. Only necessary if attributes have been added to
533 * the message.
534 *
535 * Returns the total data length of the skb.
536 */
537static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
538{
539 nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
540
541 return skb->len;
542}
543
544/**
545 * nlmsg_get_pos - return current position in netlink message
546 * @skb: socket buffer the message is stored in
547 *
548 * Returns a pointer to the current tail of the message.
549 */
550static inline void *nlmsg_get_pos(struct sk_buff *skb)
551{
552 return skb_tail_pointer(skb);
553}
554
555/**
556 * nlmsg_trim - Trim message to a mark
557 * @skb: socket buffer the message is stored in
558 * @mark: mark to trim to
559 *
560 * Trims the message to the provided mark.
561 */
562static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
563{
564 if (mark)
565 skb_trim(skb, (unsigned char *) mark - skb->data);
566}
567
568/**
569 * nlmsg_cancel - Cancel construction of a netlink message
570 * @skb: socket buffer the message is stored in
571 * @nlh: netlink message header
572 *
573 * Removes the complete netlink message including all
574 * attributes from the socket buffer again.
575 */
576static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
577{
578 nlmsg_trim(skb, nlh);
579}
580
581/**
582 * nlmsg_free - free a netlink message
583 * @skb: socket buffer of netlink message
584 */
585static inline void nlmsg_free(struct sk_buff *skb)
586{
587 kfree_skb(skb);
588}
589
590/**
591 * nlmsg_multicast - multicast a netlink message
592 * @sk: netlink socket to spread messages to
593 * @skb: netlink message as socket buffer
594 * @pid: own netlink pid to avoid sending to yourself
595 * @group: multicast group id
596 * @flags: allocation flags
597 */
598static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
599 u32 pid, unsigned int group, gfp_t flags)
600{
601 int err;
602
603 NETLINK_CB(skb).dst_group = group;
604
605 err = netlink_broadcast(sk, skb, pid, group, flags);
606 if (err > 0)
607 err = 0;
608
609 return err;
610}
611
612/**
613 * nlmsg_unicast - unicast a netlink message
614 * @sk: netlink socket to spread message to
615 * @skb: netlink message as socket buffer
616 * @pid: netlink pid of the destination socket
617 */
618static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
619{
620 int err;
621
622 err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
623 if (err > 0)
624 err = 0;
625
626 return err;
627}
628
629/**
630 * nlmsg_for_each_msg - iterate over a stream of messages
631 * @pos: loop counter, set to current message
632 * @head: head of message stream
633 * @len: length of message stream
634 * @rem: initialized to len, holds bytes currently remaining in stream
635 */
636#define nlmsg_for_each_msg(pos, head, len, rem) \
637 for (pos = head, rem = len; \
638 nlmsg_ok(pos, rem); \
639 pos = nlmsg_next(pos, &(rem)))
640
641/**
642 * nl_dump_check_consistent - check if sequence is consistent and advertise if not
643 * @cb: netlink callback structure that stores the sequence number
644 * @nlh: netlink message header to write the flag to
645 *
646 * This function checks if the sequence (generation) number changed during dump
647 * and if it did, advertises it in the netlink message header.
648 *
649 * The correct way to use it is to set cb->seq to the generation counter when
650 * all locks for dumping have been acquired, and then call this function for
651 * each message that is generated.
652 *
653 * Note that due to initialisation concerns, 0 is an invalid sequence number
654 * and must not be used by code that uses this functionality.
655 */
656static inline void
657nl_dump_check_consistent(struct netlink_callback *cb,
658 struct nlmsghdr *nlh)
659{
660 if (cb->prev_seq && cb->seq != cb->prev_seq)
661 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
662 cb->prev_seq = cb->seq;
663}
664
665/**************************************************************************
666 * Netlink Attributes
667 **************************************************************************/
668
669/**
670 * nla_attr_size - length of attribute not including padding
671 * @payload: length of payload
672 */
673static inline int nla_attr_size(int payload)
674{
675 return NLA_HDRLEN + payload;
676}
677
678/**
679 * nla_total_size - total length of attribute including padding
680 * @payload: length of payload
681 */
682static inline int nla_total_size(int payload)
683{
684 return NLA_ALIGN(nla_attr_size(payload));
685}
686
687/**
688 * nla_padlen - length of padding at the tail of attribute
689 * @payload: length of payload
690 */
691static inline int nla_padlen(int payload)
692{
693 return nla_total_size(payload) - nla_attr_size(payload);
694}
695
696/**
697 * nla_type - attribute type
698 * @nla: netlink attribute
699 */
700static inline int nla_type(const struct nlattr *nla)
701{
702 return nla->nla_type & NLA_TYPE_MASK;
703}
704
705/**
706 * nla_data - head of payload
707 * @nla: netlink attribute
708 */
709static inline void *nla_data(const struct nlattr *nla)
710{
711 return (char *) nla + NLA_HDRLEN;
712}
713
714/**
715 * nla_len - length of payload
716 * @nla: netlink attribute
717 */
718static inline int nla_len(const struct nlattr *nla)
719{
720 return nla->nla_len - NLA_HDRLEN;
721}
722
723/**
724 * nla_ok - check if the netlink attribute fits into the remaining bytes
725 * @nla: netlink attribute
726 * @remaining: number of bytes remaining in attribute stream
727 */
728static inline int nla_ok(const struct nlattr *nla, int remaining)
729{
730 return remaining >= (int) sizeof(*nla) &&
731 nla->nla_len >= sizeof(*nla) &&
732 nla->nla_len <= remaining;
733}
734
735/**
736 * nla_next - next netlink attribute in attribute stream
737 * @nla: netlink attribute
738 * @remaining: number of bytes remaining in attribute stream
739 *
740 * Returns the next netlink attribute in the attribute stream and
741 * decrements remaining by the size of the current attribute.
742 */
743static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
744{
745 int totlen = NLA_ALIGN(nla->nla_len);
746
747 *remaining -= totlen;
748 return (struct nlattr *) ((char *) nla + totlen);
749}
750
751/**
752 * nla_find_nested - find attribute in a set of nested attributes
753 * @nla: attribute containing the nested attributes
754 * @attrtype: type of attribute to look for
755 *
756 * Returns the first attribute which matches the specified type.
757 */
758static inline struct nlattr *
759nla_find_nested(const struct nlattr *nla, int attrtype)
760{
761 return nla_find(nla_data(nla), nla_len(nla), attrtype);
762}
763
764/**
765 * nla_parse_nested - parse nested attributes
766 * @tb: destination array with maxtype+1 elements
767 * @maxtype: maximum attribute type to be expected
768 * @nla: attribute containing the nested attributes
769 * @policy: validation policy
770 *
771 * See nla_parse()
772 */
773static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
774 const struct nlattr *nla,
775 const struct nla_policy *policy)
776{
777 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
778}
779
780/**
781 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
782 * @skb: socket buffer to add attribute to
783 * @attrtype: attribute type
784 * @value: numeric value
785 */
786static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
787{
788 return nla_put(skb, attrtype, sizeof(u8), &value);
789}
790
791/**
792 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
793 * @skb: socket buffer to add attribute to
794 * @attrtype: attribute type
795 * @value: numeric value
796 */
797static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
798{
799 return nla_put(skb, attrtype, sizeof(u16), &value);
800}
801
802/**
803 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
804 * @skb: socket buffer to add attribute to
805 * @attrtype: attribute type
806 * @value: numeric value
807 */
808static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
809{
810 return nla_put(skb, attrtype, sizeof(u32), &value);
811}
812
813/**
814 * nla_put_64 - Add a u64 netlink attribute to a socket buffer
815 * @skb: socket buffer to add attribute to
816 * @attrtype: attribute type
817 * @value: numeric value
818 */
819static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
820{
821 return nla_put(skb, attrtype, sizeof(u64), &value);
822}
823
824/**
825 * nla_put_string - Add a string netlink attribute to a socket buffer
826 * @skb: socket buffer to add attribute to
827 * @attrtype: attribute type
828 * @str: NUL terminated string
829 */
830static inline int nla_put_string(struct sk_buff *skb, int attrtype,
831 const char *str)
832{
833 return nla_put(skb, attrtype, strlen(str) + 1, str);
834}
835
836/**
837 * nla_put_flag - Add a flag netlink attribute to a socket buffer
838 * @skb: socket buffer to add attribute to
839 * @attrtype: attribute type
840 */
841static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
842{
843 return nla_put(skb, attrtype, 0, NULL);
844}
845
846/**
847 * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
848 * @skb: socket buffer to add attribute to
849 * @attrtype: attribute type
850 * @jiffies: number of msecs in jiffies
851 */
852static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
853 unsigned long jiffies)
854{
855 u64 tmp = jiffies_to_msecs(jiffies);
856 return nla_put(skb, attrtype, sizeof(u64), &tmp);
857}
858
859#define NLA_PUT(skb, attrtype, attrlen, data) \
860 do { \
861 if (unlikely(nla_put(skb, attrtype, attrlen, data) < 0)) \
862 goto nla_put_failure; \
863 } while(0)
864
865#define NLA_PUT_TYPE(skb, type, attrtype, value) \
866 do { \
867 type __tmp = value; \
868 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
869 } while(0)
870
871#define NLA_PUT_U8(skb, attrtype, value) \
872 NLA_PUT_TYPE(skb, u8, attrtype, value)
873
874#define NLA_PUT_U16(skb, attrtype, value) \
875 NLA_PUT_TYPE(skb, u16, attrtype, value)
876
877#define NLA_PUT_LE16(skb, attrtype, value) \
878 NLA_PUT_TYPE(skb, __le16, attrtype, value)
879
880#define NLA_PUT_BE16(skb, attrtype, value) \
881 NLA_PUT_TYPE(skb, __be16, attrtype, value)
882
883#define NLA_PUT_NET16(skb, attrtype, value) \
884 NLA_PUT_BE16(skb, attrtype | NLA_F_NET_BYTEORDER, value)
885
886#define NLA_PUT_U32(skb, attrtype, value) \
887 NLA_PUT_TYPE(skb, u32, attrtype, value)
888
889#define NLA_PUT_BE32(skb, attrtype, value) \
890 NLA_PUT_TYPE(skb, __be32, attrtype, value)
891
892#define NLA_PUT_NET32(skb, attrtype, value) \
893 NLA_PUT_BE32(skb, attrtype | NLA_F_NET_BYTEORDER, value)
894
895#define NLA_PUT_U64(skb, attrtype, value) \
896 NLA_PUT_TYPE(skb, u64, attrtype, value)
897
898#define NLA_PUT_BE64(skb, attrtype, value) \
899 NLA_PUT_TYPE(skb, __be64, attrtype, value)
900
901#define NLA_PUT_NET64(skb, attrtype, value) \
902 NLA_PUT_BE64(skb, attrtype | NLA_F_NET_BYTEORDER, value)
903
904#define NLA_PUT_STRING(skb, attrtype, value) \
905 NLA_PUT(skb, attrtype, strlen(value) + 1, value)
906
907#define NLA_PUT_FLAG(skb, attrtype) \
908 NLA_PUT(skb, attrtype, 0, NULL)
909
910#define NLA_PUT_MSECS(skb, attrtype, jiffies) \
911 NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
912
913/**
914 * nla_get_u32 - return payload of u32 attribute
915 * @nla: u32 netlink attribute
916 */
917static inline u32 nla_get_u32(const struct nlattr *nla)
918{
919 return *(u32 *) nla_data(nla);
920}
921
922/**
923 * nla_get_be32 - return payload of __be32 attribute
924 * @nla: __be32 netlink attribute
925 */
926static inline __be32 nla_get_be32(const struct nlattr *nla)
927{
928 return *(__be32 *) nla_data(nla);
929}
930
931/**
932 * nla_get_u16 - return payload of u16 attribute
933 * @nla: u16 netlink attribute
934 */
935static inline u16 nla_get_u16(const struct nlattr *nla)
936{
937 return *(u16 *) nla_data(nla);
938}
939
940/**
941 * nla_get_be16 - return payload of __be16 attribute
942 * @nla: __be16 netlink attribute
943 */
944static inline __be16 nla_get_be16(const struct nlattr *nla)
945{
946 return *(__be16 *) nla_data(nla);
947}
948
949/**
950 * nla_get_le16 - return payload of __le16 attribute
951 * @nla: __le16 netlink attribute
952 */
953static inline __le16 nla_get_le16(const struct nlattr *nla)
954{
955 return *(__le16 *) nla_data(nla);
956}
957
958/**
959 * nla_get_u8 - return payload of u8 attribute
960 * @nla: u8 netlink attribute
961 */
962static inline u8 nla_get_u8(const struct nlattr *nla)
963{
964 return *(u8 *) nla_data(nla);
965}
966
967/**
968 * nla_get_u64 - return payload of u64 attribute
969 * @nla: u64 netlink attribute
970 */
971static inline u64 nla_get_u64(const struct nlattr *nla)
972{
973 u64 tmp;
974
975 nla_memcpy(&tmp, nla, sizeof(tmp));
976
977 return tmp;
978}
979
980/**
981 * nla_get_be64 - return payload of __be64 attribute
982 * @nla: __be64 netlink attribute
983 */
984static inline __be64 nla_get_be64(const struct nlattr *nla)
985{
986 __be64 tmp;
987
988 nla_memcpy(&tmp, nla, sizeof(tmp));
989
990 return tmp;
991}
992
993/**
994 * nla_get_flag - return payload of flag attribute
995 * @nla: flag netlink attribute
996 */
997static inline int nla_get_flag(const struct nlattr *nla)
998{
999 return !!nla;
1000}
1001
1002/**
1003 * nla_get_msecs - return payload of msecs attribute
1004 * @nla: msecs netlink attribute
1005 *
1006 * Returns the number of milliseconds in jiffies.
1007 */
1008static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1009{
1010 u64 msecs = nla_get_u64(nla);
1011
1012 return msecs_to_jiffies((unsigned long) msecs);
1013}
1014
1015/**
1016 * nla_nest_start - Start a new level of nested attributes
1017 * @skb: socket buffer to add attributes to
1018 * @attrtype: attribute type of container
1019 *
1020 * Returns the container attribute
1021 */
1022static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1023{
1024 struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1025
1026 if (nla_put(skb, attrtype, 0, NULL) < 0)
1027 return NULL;
1028
1029 return start;
1030}
1031
1032/**
1033 * nla_nest_end - Finalize nesting of attributes
1034 * @skb: socket buffer the attributes are stored in
1035 * @start: container attribute
1036 *
1037 * Corrects the container attribute header to include the all
1038 * appeneded attributes.
1039 *
1040 * Returns the total data length of the skb.
1041 */
1042static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1043{
1044 start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1045 return skb->len;
1046}
1047
1048/**
1049 * nla_nest_cancel - Cancel nesting of attributes
1050 * @skb: socket buffer the message is stored in
1051 * @start: container attribute
1052 *
1053 * Removes the container attribute and including all nested
1054 * attributes. Returns -EMSGSIZE
1055 */
1056static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1057{
1058 nlmsg_trim(skb, start);
1059}
1060
1061/**
1062 * nla_validate_nested - Validate a stream of nested attributes
1063 * @start: container attribute
1064 * @maxtype: maximum attribute type to be expected
1065 * @policy: validation policy
1066 *
1067 * Validates all attributes in the nested attribute stream against the
1068 * specified policy. Attributes with a type exceeding maxtype will be
1069 * ignored. See documenation of struct nla_policy for more details.
1070 *
1071 * Returns 0 on success or a negative error code.
1072 */
1073static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1074 const struct nla_policy *policy)
1075{
1076 return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1077}
1078
1079/**
1080 * nla_for_each_attr - iterate over a stream of attributes
1081 * @pos: loop counter, set to current attribute
1082 * @head: head of attribute stream
1083 * @len: length of attribute stream
1084 * @rem: initialized to len, holds bytes currently remaining in stream
1085 */
1086#define nla_for_each_attr(pos, head, len, rem) \
1087 for (pos = head, rem = len; \
1088 nla_ok(pos, rem); \
1089 pos = nla_next(pos, &(rem)))
1090
1091/**
1092 * nla_for_each_nested - iterate over nested attributes
1093 * @pos: loop counter, set to current attribute
1094 * @nla: attribute containing the nested attributes
1095 * @rem: initialized to len, holds bytes currently remaining in stream
1096 */
1097#define nla_for_each_nested(pos, nla, rem) \
1098 nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1099
1100#endif
1#ifndef __NET_NETLINK_H
2#define __NET_NETLINK_H
3
4#include <linux/types.h>
5#include <linux/netlink.h>
6#include <linux/jiffies.h>
7
8/* ========================================================================
9 * Netlink Messages and Attributes Interface (As Seen On TV)
10 * ------------------------------------------------------------------------
11 * Messages Interface
12 * ------------------------------------------------------------------------
13 *
14 * Message Format:
15 * <--- nlmsg_total_size(payload) --->
16 * <-- nlmsg_msg_size(payload) ->
17 * +----------+- - -+-------------+- - -+-------- - -
18 * | nlmsghdr | Pad | Payload | Pad | nlmsghdr
19 * +----------+- - -+-------------+- - -+-------- - -
20 * nlmsg_data(nlh)---^ ^
21 * nlmsg_next(nlh)-----------------------+
22 *
23 * Payload Format:
24 * <---------------------- nlmsg_len(nlh) --------------------->
25 * <------ hdrlen ------> <- nlmsg_attrlen(nlh, hdrlen) ->
26 * +----------------------+- - -+--------------------------------+
27 * | Family Header | Pad | Attributes |
28 * +----------------------+- - -+--------------------------------+
29 * nlmsg_attrdata(nlh, hdrlen)---^
30 *
31 * Data Structures:
32 * struct nlmsghdr netlink message header
33 *
34 * Message Construction:
35 * nlmsg_new() create a new netlink message
36 * nlmsg_put() add a netlink message to an skb
37 * nlmsg_put_answer() callback based nlmsg_put()
38 * nlmsg_end() finalize netlink message
39 * nlmsg_get_pos() return current position in message
40 * nlmsg_trim() trim part of message
41 * nlmsg_cancel() cancel message construction
42 * nlmsg_free() free a netlink message
43 *
44 * Message Sending:
45 * nlmsg_multicast() multicast message to several groups
46 * nlmsg_unicast() unicast a message to a single socket
47 * nlmsg_notify() send notification message
48 *
49 * Message Length Calculations:
50 * nlmsg_msg_size(payload) length of message w/o padding
51 * nlmsg_total_size(payload) length of message w/ padding
52 * nlmsg_padlen(payload) length of padding at tail
53 *
54 * Message Payload Access:
55 * nlmsg_data(nlh) head of message payload
56 * nlmsg_len(nlh) length of message payload
57 * nlmsg_attrdata(nlh, hdrlen) head of attributes data
58 * nlmsg_attrlen(nlh, hdrlen) length of attributes data
59 *
60 * Message Parsing:
61 * nlmsg_ok(nlh, remaining) does nlh fit into remaining bytes?
62 * nlmsg_next(nlh, remaining) get next netlink message
63 * nlmsg_parse() parse attributes of a message
64 * nlmsg_find_attr() find an attribute in a message
65 * nlmsg_for_each_msg() loop over all messages
66 * nlmsg_validate() validate netlink message incl. attrs
67 * nlmsg_for_each_attr() loop over all attributes
68 *
69 * Misc:
70 * nlmsg_report() report back to application?
71 *
72 * ------------------------------------------------------------------------
73 * Attributes Interface
74 * ------------------------------------------------------------------------
75 *
76 * Attribute Format:
77 * <------- nla_total_size(payload) ------->
78 * <---- nla_attr_size(payload) ----->
79 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
80 * | Header | Pad | Payload | Pad | Header
81 * +----------+- - -+- - - - - - - - - +- - -+-------- - -
82 * <- nla_len(nla) -> ^
83 * nla_data(nla)----^ |
84 * nla_next(nla)-----------------------------'
85 *
86 * Data Structures:
87 * struct nlattr netlink attribute header
88 *
89 * Attribute Construction:
90 * nla_reserve(skb, type, len) reserve room for an attribute
91 * nla_reserve_nohdr(skb, len) reserve room for an attribute w/o hdr
92 * nla_put(skb, type, len, data) add attribute to skb
93 * nla_put_nohdr(skb, len, data) add attribute w/o hdr
94 * nla_append(skb, len, data) append data to skb
95 *
96 * Attribute Construction for Basic Types:
97 * nla_put_u8(skb, type, value) add u8 attribute to skb
98 * nla_put_u16(skb, type, value) add u16 attribute to skb
99 * nla_put_u32(skb, type, value) add u32 attribute to skb
100 * nla_put_u64(skb, type, value) add u64 attribute to skb
101 * nla_put_string(skb, type, str) add string attribute to skb
102 * nla_put_flag(skb, type) add flag attribute to skb
103 * nla_put_msecs(skb, type, jiffies) add msecs attribute to skb
104 *
105 * Nested Attributes Construction:
106 * nla_nest_start(skb, type) start a nested attribute
107 * nla_nest_end(skb, nla) finalize a nested attribute
108 * nla_nest_cancel(skb, nla) cancel nested attribute construction
109 *
110 * Attribute Length Calculations:
111 * nla_attr_size(payload) length of attribute w/o padding
112 * nla_total_size(payload) length of attribute w/ padding
113 * nla_padlen(payload) length of padding
114 *
115 * Attribute Payload Access:
116 * nla_data(nla) head of attribute payload
117 * nla_len(nla) length of attribute payload
118 *
119 * Attribute Payload Access for Basic Types:
120 * nla_get_u8(nla) get payload for a u8 attribute
121 * nla_get_u16(nla) get payload for a u16 attribute
122 * nla_get_u32(nla) get payload for a u32 attribute
123 * nla_get_u64(nla) get payload for a u64 attribute
124 * nla_get_flag(nla) return 1 if flag is true
125 * nla_get_msecs(nla) get payload for a msecs attribute
126 *
127 * Attribute Misc:
128 * nla_memcpy(dest, nla, count) copy attribute into memory
129 * nla_memcmp(nla, data, size) compare attribute with memory area
130 * nla_strlcpy(dst, nla, size) copy attribute to a sized string
131 * nla_strcmp(nla, str) compare attribute with string
132 *
133 * Attribute Parsing:
134 * nla_ok(nla, remaining) does nla fit into remaining bytes?
135 * nla_next(nla, remaining) get next netlink attribute
136 * nla_validate() validate a stream of attributes
137 * nla_validate_nested() validate a stream of nested attributes
138 * nla_find() find attribute in stream of attributes
139 * nla_find_nested() find attribute in nested attributes
140 * nla_parse() parse and validate stream of attrs
141 * nla_parse_nested() parse nested attribuets
142 * nla_for_each_attr() loop over all attributes
143 * nla_for_each_nested() loop over the nested attributes
144 *=========================================================================
145 */
146
147 /**
148 * Standard attribute types to specify validation policy
149 */
150enum {
151 NLA_UNSPEC,
152 NLA_U8,
153 NLA_U16,
154 NLA_U32,
155 NLA_U64,
156 NLA_STRING,
157 NLA_FLAG,
158 NLA_MSECS,
159 NLA_NESTED,
160 NLA_NESTED_COMPAT,
161 NLA_NUL_STRING,
162 NLA_BINARY,
163 __NLA_TYPE_MAX,
164};
165
166#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
167
168/**
169 * struct nla_policy - attribute validation policy
170 * @type: Type of attribute or NLA_UNSPEC
171 * @len: Type specific length of payload
172 *
173 * Policies are defined as arrays of this struct, the array must be
174 * accessible by attribute type up to the highest identifier to be expected.
175 *
176 * Meaning of `len' field:
177 * NLA_STRING Maximum length of string
178 * NLA_NUL_STRING Maximum length of string (excluding NUL)
179 * NLA_FLAG Unused
180 * NLA_BINARY Maximum length of attribute payload
181 * NLA_NESTED Don't use `len' field -- length verification is
182 * done by checking len of nested header (or empty)
183 * NLA_NESTED_COMPAT Minimum length of structure payload
184 * NLA_U8, NLA_U16,
185 * NLA_U32, NLA_U64,
186 * NLA_MSECS Leaving the length field zero will verify the
187 * given type fits, using it verifies minimum length
188 * just like "All other"
189 * All other Minimum length of attribute payload
190 *
191 * Example:
192 * static const struct nla_policy my_policy[ATTR_MAX+1] = {
193 * [ATTR_FOO] = { .type = NLA_U16 },
194 * [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
195 * [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
196 * };
197 */
198struct nla_policy {
199 u16 type;
200 u16 len;
201};
202
203/**
204 * struct nl_info - netlink source information
205 * @nlh: Netlink message header of original request
206 * @pid: Netlink PID of requesting application
207 */
208struct nl_info {
209 struct nlmsghdr *nlh;
210 struct net *nl_net;
211 u32 pid;
212};
213
214extern int netlink_rcv_skb(struct sk_buff *skb,
215 int (*cb)(struct sk_buff *,
216 struct nlmsghdr *));
217extern int nlmsg_notify(struct sock *sk, struct sk_buff *skb,
218 u32 pid, unsigned int group, int report,
219 gfp_t flags);
220
221extern int nla_validate(const struct nlattr *head,
222 int len, int maxtype,
223 const struct nla_policy *policy);
224extern int nla_parse(struct nlattr **tb, int maxtype,
225 const struct nlattr *head, int len,
226 const struct nla_policy *policy);
227extern int nla_policy_len(const struct nla_policy *, int);
228extern struct nlattr * nla_find(const struct nlattr *head,
229 int len, int attrtype);
230extern size_t nla_strlcpy(char *dst, const struct nlattr *nla,
231 size_t dstsize);
232extern int nla_memcpy(void *dest, const struct nlattr *src, int count);
233extern int nla_memcmp(const struct nlattr *nla, const void *data,
234 size_t size);
235extern int nla_strcmp(const struct nlattr *nla, const char *str);
236extern struct nlattr * __nla_reserve(struct sk_buff *skb, int attrtype,
237 int attrlen);
238extern void * __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
239extern struct nlattr * nla_reserve(struct sk_buff *skb, int attrtype,
240 int attrlen);
241extern void * nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
242extern void __nla_put(struct sk_buff *skb, int attrtype,
243 int attrlen, const void *data);
244extern void __nla_put_nohdr(struct sk_buff *skb, int attrlen,
245 const void *data);
246extern int nla_put(struct sk_buff *skb, int attrtype,
247 int attrlen, const void *data);
248extern int nla_put_nohdr(struct sk_buff *skb, int attrlen,
249 const void *data);
250extern int nla_append(struct sk_buff *skb, int attrlen,
251 const void *data);
252
253/**************************************************************************
254 * Netlink Messages
255 **************************************************************************/
256
257/**
258 * nlmsg_msg_size - length of netlink message not including padding
259 * @payload: length of message payload
260 */
261static inline int nlmsg_msg_size(int payload)
262{
263 return NLMSG_HDRLEN + payload;
264}
265
266/**
267 * nlmsg_total_size - length of netlink message including padding
268 * @payload: length of message payload
269 */
270static inline int nlmsg_total_size(int payload)
271{
272 return NLMSG_ALIGN(nlmsg_msg_size(payload));
273}
274
275/**
276 * nlmsg_padlen - length of padding at the message's tail
277 * @payload: length of message payload
278 */
279static inline int nlmsg_padlen(int payload)
280{
281 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
282}
283
284/**
285 * nlmsg_data - head of message payload
286 * @nlh: netlink message header
287 */
288static inline void *nlmsg_data(const struct nlmsghdr *nlh)
289{
290 return (unsigned char *) nlh + NLMSG_HDRLEN;
291}
292
293/**
294 * nlmsg_len - length of message payload
295 * @nlh: netlink message header
296 */
297static inline int nlmsg_len(const struct nlmsghdr *nlh)
298{
299 return nlh->nlmsg_len - NLMSG_HDRLEN;
300}
301
302/**
303 * nlmsg_attrdata - head of attributes data
304 * @nlh: netlink message header
305 * @hdrlen: length of family specific header
306 */
307static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
308 int hdrlen)
309{
310 unsigned char *data = nlmsg_data(nlh);
311 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
312}
313
314/**
315 * nlmsg_attrlen - length of attributes data
316 * @nlh: netlink message header
317 * @hdrlen: length of family specific header
318 */
319static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
320{
321 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
322}
323
324/**
325 * nlmsg_ok - check if the netlink message fits into the remaining bytes
326 * @nlh: netlink message header
327 * @remaining: number of bytes remaining in message stream
328 */
329static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
330{
331 return (remaining >= (int) sizeof(struct nlmsghdr) &&
332 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
333 nlh->nlmsg_len <= remaining);
334}
335
336/**
337 * nlmsg_next - next netlink message in message stream
338 * @nlh: netlink message header
339 * @remaining: number of bytes remaining in message stream
340 *
341 * Returns the next netlink message in the message stream and
342 * decrements remaining by the size of the current message.
343 */
344static inline struct nlmsghdr *
345nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
346{
347 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
348
349 *remaining -= totlen;
350
351 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
352}
353
354/**
355 * nlmsg_parse - parse attributes of a netlink message
356 * @nlh: netlink message header
357 * @hdrlen: length of family specific header
358 * @tb: destination array with maxtype+1 elements
359 * @maxtype: maximum attribute type to be expected
360 * @policy: validation policy
361 *
362 * See nla_parse()
363 */
364static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
365 struct nlattr *tb[], int maxtype,
366 const struct nla_policy *policy)
367{
368 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
369 return -EINVAL;
370
371 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
372 nlmsg_attrlen(nlh, hdrlen), policy);
373}
374
375/**
376 * nlmsg_find_attr - find a specific attribute in a netlink message
377 * @nlh: netlink message header
378 * @hdrlen: length of familiy specific header
379 * @attrtype: type of attribute to look for
380 *
381 * Returns the first attribute which matches the specified type.
382 */
383static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
384 int hdrlen, int attrtype)
385{
386 return nla_find(nlmsg_attrdata(nlh, hdrlen),
387 nlmsg_attrlen(nlh, hdrlen), attrtype);
388}
389
390/**
391 * nlmsg_validate - validate a netlink message including attributes
392 * @nlh: netlinket message header
393 * @hdrlen: length of familiy specific header
394 * @maxtype: maximum attribute type to be expected
395 * @policy: validation policy
396 */
397static inline int nlmsg_validate(const struct nlmsghdr *nlh,
398 int hdrlen, int maxtype,
399 const struct nla_policy *policy)
400{
401 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
402 return -EINVAL;
403
404 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
405 nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
406}
407
408/**
409 * nlmsg_report - need to report back to application?
410 * @nlh: netlink message header
411 *
412 * Returns 1 if a report back to the application is requested.
413 */
414static inline int nlmsg_report(const struct nlmsghdr *nlh)
415{
416 return !!(nlh->nlmsg_flags & NLM_F_ECHO);
417}
418
419/**
420 * nlmsg_for_each_attr - iterate over a stream of attributes
421 * @pos: loop counter, set to current attribute
422 * @nlh: netlink message header
423 * @hdrlen: length of familiy specific header
424 * @rem: initialized to len, holds bytes currently remaining in stream
425 */
426#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
427 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
428 nlmsg_attrlen(nlh, hdrlen), rem)
429
430/**
431 * nlmsg_put - Add a new netlink message to an skb
432 * @skb: socket buffer to store message in
433 * @pid: netlink process id
434 * @seq: sequence number of message
435 * @type: message type
436 * @payload: length of message payload
437 * @flags: message flags
438 *
439 * Returns NULL if the tailroom of the skb is insufficient to store
440 * the message header and payload.
441 */
442static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
443 int type, int payload, int flags)
444{
445 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
446 return NULL;
447
448 return __nlmsg_put(skb, pid, seq, type, payload, flags);
449}
450
451/**
452 * nlmsg_put_answer - Add a new callback based netlink message to an skb
453 * @skb: socket buffer to store message in
454 * @cb: netlink callback
455 * @type: message type
456 * @payload: length of message payload
457 * @flags: message flags
458 *
459 * Returns NULL if the tailroom of the skb is insufficient to store
460 * the message header and payload.
461 */
462static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
463 struct netlink_callback *cb,
464 int type, int payload,
465 int flags)
466{
467 return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
468 type, payload, flags);
469}
470
471/**
472 * nlmsg_new - Allocate a new netlink message
473 * @payload: size of the message payload
474 * @flags: the type of memory to allocate.
475 *
476 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
477 * and a good default is needed.
478 */
479static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
480{
481 return alloc_skb(nlmsg_total_size(payload), flags);
482}
483
484/**
485 * nlmsg_end - Finalize a netlink message
486 * @skb: socket buffer the message is stored in
487 * @nlh: netlink message header
488 *
489 * Corrects the netlink message header to include the appeneded
490 * attributes. Only necessary if attributes have been added to
491 * the message.
492 *
493 * Returns the total data length of the skb.
494 */
495static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
496{
497 nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
498
499 return skb->len;
500}
501
502/**
503 * nlmsg_get_pos - return current position in netlink message
504 * @skb: socket buffer the message is stored in
505 *
506 * Returns a pointer to the current tail of the message.
507 */
508static inline void *nlmsg_get_pos(struct sk_buff *skb)
509{
510 return skb_tail_pointer(skb);
511}
512
513/**
514 * nlmsg_trim - Trim message to a mark
515 * @skb: socket buffer the message is stored in
516 * @mark: mark to trim to
517 *
518 * Trims the message to the provided mark.
519 */
520static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
521{
522 if (mark)
523 skb_trim(skb, (unsigned char *) mark - skb->data);
524}
525
526/**
527 * nlmsg_cancel - Cancel construction of a netlink message
528 * @skb: socket buffer the message is stored in
529 * @nlh: netlink message header
530 *
531 * Removes the complete netlink message including all
532 * attributes from the socket buffer again.
533 */
534static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
535{
536 nlmsg_trim(skb, nlh);
537}
538
539/**
540 * nlmsg_free - free a netlink message
541 * @skb: socket buffer of netlink message
542 */
543static inline void nlmsg_free(struct sk_buff *skb)
544{
545 kfree_skb(skb);
546}
547
548/**
549 * nlmsg_multicast - multicast a netlink message
550 * @sk: netlink socket to spread messages to
551 * @skb: netlink message as socket buffer
552 * @pid: own netlink pid to avoid sending to yourself
553 * @group: multicast group id
554 * @flags: allocation flags
555 */
556static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
557 u32 pid, unsigned int group, gfp_t flags)
558{
559 int err;
560
561 NETLINK_CB(skb).dst_group = group;
562
563 err = netlink_broadcast(sk, skb, pid, group, flags);
564 if (err > 0)
565 err = 0;
566
567 return err;
568}
569
570/**
571 * nlmsg_unicast - unicast a netlink message
572 * @sk: netlink socket to spread message to
573 * @skb: netlink message as socket buffer
574 * @pid: netlink pid of the destination socket
575 */
576static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
577{
578 int err;
579
580 err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
581 if (err > 0)
582 err = 0;
583
584 return err;
585}
586
587/**
588 * nlmsg_for_each_msg - iterate over a stream of messages
589 * @pos: loop counter, set to current message
590 * @head: head of message stream
591 * @len: length of message stream
592 * @rem: initialized to len, holds bytes currently remaining in stream
593 */
594#define nlmsg_for_each_msg(pos, head, len, rem) \
595 for (pos = head, rem = len; \
596 nlmsg_ok(pos, rem); \
597 pos = nlmsg_next(pos, &(rem)))
598
599/**
600 * nl_dump_check_consistent - check if sequence is consistent and advertise if not
601 * @cb: netlink callback structure that stores the sequence number
602 * @nlh: netlink message header to write the flag to
603 *
604 * This function checks if the sequence (generation) number changed during dump
605 * and if it did, advertises it in the netlink message header.
606 *
607 * The correct way to use it is to set cb->seq to the generation counter when
608 * all locks for dumping have been acquired, and then call this function for
609 * each message that is generated.
610 *
611 * Note that due to initialisation concerns, 0 is an invalid sequence number
612 * and must not be used by code that uses this functionality.
613 */
614static inline void
615nl_dump_check_consistent(struct netlink_callback *cb,
616 struct nlmsghdr *nlh)
617{
618 if (cb->prev_seq && cb->seq != cb->prev_seq)
619 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
620 cb->prev_seq = cb->seq;
621}
622
623/**************************************************************************
624 * Netlink Attributes
625 **************************************************************************/
626
627/**
628 * nla_attr_size - length of attribute not including padding
629 * @payload: length of payload
630 */
631static inline int nla_attr_size(int payload)
632{
633 return NLA_HDRLEN + payload;
634}
635
636/**
637 * nla_total_size - total length of attribute including padding
638 * @payload: length of payload
639 */
640static inline int nla_total_size(int payload)
641{
642 return NLA_ALIGN(nla_attr_size(payload));
643}
644
645/**
646 * nla_padlen - length of padding at the tail of attribute
647 * @payload: length of payload
648 */
649static inline int nla_padlen(int payload)
650{
651 return nla_total_size(payload) - nla_attr_size(payload);
652}
653
654/**
655 * nla_type - attribute type
656 * @nla: netlink attribute
657 */
658static inline int nla_type(const struct nlattr *nla)
659{
660 return nla->nla_type & NLA_TYPE_MASK;
661}
662
663/**
664 * nla_data - head of payload
665 * @nla: netlink attribute
666 */
667static inline void *nla_data(const struct nlattr *nla)
668{
669 return (char *) nla + NLA_HDRLEN;
670}
671
672/**
673 * nla_len - length of payload
674 * @nla: netlink attribute
675 */
676static inline int nla_len(const struct nlattr *nla)
677{
678 return nla->nla_len - NLA_HDRLEN;
679}
680
681/**
682 * nla_ok - check if the netlink attribute fits into the remaining bytes
683 * @nla: netlink attribute
684 * @remaining: number of bytes remaining in attribute stream
685 */
686static inline int nla_ok(const struct nlattr *nla, int remaining)
687{
688 return remaining >= (int) sizeof(*nla) &&
689 nla->nla_len >= sizeof(*nla) &&
690 nla->nla_len <= remaining;
691}
692
693/**
694 * nla_next - next netlink attribute in attribute stream
695 * @nla: netlink attribute
696 * @remaining: number of bytes remaining in attribute stream
697 *
698 * Returns the next netlink attribute in the attribute stream and
699 * decrements remaining by the size of the current attribute.
700 */
701static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
702{
703 int totlen = NLA_ALIGN(nla->nla_len);
704
705 *remaining -= totlen;
706 return (struct nlattr *) ((char *) nla + totlen);
707}
708
709/**
710 * nla_find_nested - find attribute in a set of nested attributes
711 * @nla: attribute containing the nested attributes
712 * @attrtype: type of attribute to look for
713 *
714 * Returns the first attribute which matches the specified type.
715 */
716static inline struct nlattr *
717nla_find_nested(const struct nlattr *nla, int attrtype)
718{
719 return nla_find(nla_data(nla), nla_len(nla), attrtype);
720}
721
722/**
723 * nla_parse_nested - parse nested attributes
724 * @tb: destination array with maxtype+1 elements
725 * @maxtype: maximum attribute type to be expected
726 * @nla: attribute containing the nested attributes
727 * @policy: validation policy
728 *
729 * See nla_parse()
730 */
731static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
732 const struct nlattr *nla,
733 const struct nla_policy *policy)
734{
735 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
736}
737
738/**
739 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
740 * @skb: socket buffer to add attribute to
741 * @attrtype: attribute type
742 * @value: numeric value
743 */
744static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
745{
746 return nla_put(skb, attrtype, sizeof(u8), &value);
747}
748
749/**
750 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
751 * @skb: socket buffer to add attribute to
752 * @attrtype: attribute type
753 * @value: numeric value
754 */
755static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
756{
757 return nla_put(skb, attrtype, sizeof(u16), &value);
758}
759
760/**
761 * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
762 * @skb: socket buffer to add attribute to
763 * @attrtype: attribute type
764 * @value: numeric value
765 */
766static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
767{
768 return nla_put(skb, attrtype, sizeof(__be16), &value);
769}
770
771/**
772 * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
773 * @skb: socket buffer to add attribute to
774 * @attrtype: attribute type
775 * @value: numeric value
776 */
777static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
778{
779 return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
780}
781
782/**
783 * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
784 * @skb: socket buffer to add attribute to
785 * @attrtype: attribute type
786 * @value: numeric value
787 */
788static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
789{
790 return nla_put(skb, attrtype, sizeof(__le16), &value);
791}
792
793/**
794 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
795 * @skb: socket buffer to add attribute to
796 * @attrtype: attribute type
797 * @value: numeric value
798 */
799static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
800{
801 return nla_put(skb, attrtype, sizeof(u32), &value);
802}
803
804/**
805 * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
806 * @skb: socket buffer to add attribute to
807 * @attrtype: attribute type
808 * @value: numeric value
809 */
810static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
811{
812 return nla_put(skb, attrtype, sizeof(__be32), &value);
813}
814
815/**
816 * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
817 * @skb: socket buffer to add attribute to
818 * @attrtype: attribute type
819 * @value: numeric value
820 */
821static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
822{
823 return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
824}
825
826/**
827 * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
828 * @skb: socket buffer to add attribute to
829 * @attrtype: attribute type
830 * @value: numeric value
831 */
832static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
833{
834 return nla_put(skb, attrtype, sizeof(__le32), &value);
835}
836
837/**
838 * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
839 * @skb: socket buffer to add attribute to
840 * @attrtype: attribute type
841 * @value: numeric value
842 */
843static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
844{
845 return nla_put(skb, attrtype, sizeof(u64), &value);
846}
847
848/**
849 * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer
850 * @skb: socket buffer to add attribute to
851 * @attrtype: attribute type
852 * @value: numeric value
853 */
854static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value)
855{
856 return nla_put(skb, attrtype, sizeof(__be64), &value);
857}
858
859/**
860 * nla_put_net64 - Add 64-bit network byte order netlink attribute to a socket buffer
861 * @skb: socket buffer to add attribute to
862 * @attrtype: attribute type
863 * @value: numeric value
864 */
865static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value)
866{
867 return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value);
868}
869
870/**
871 * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer
872 * @skb: socket buffer to add attribute to
873 * @attrtype: attribute type
874 * @value: numeric value
875 */
876static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value)
877{
878 return nla_put(skb, attrtype, sizeof(__le64), &value);
879}
880
881/**
882 * nla_put_string - Add a string netlink attribute to a socket buffer
883 * @skb: socket buffer to add attribute to
884 * @attrtype: attribute type
885 * @str: NUL terminated string
886 */
887static inline int nla_put_string(struct sk_buff *skb, int attrtype,
888 const char *str)
889{
890 return nla_put(skb, attrtype, strlen(str) + 1, str);
891}
892
893/**
894 * nla_put_flag - Add a flag netlink attribute to a socket buffer
895 * @skb: socket buffer to add attribute to
896 * @attrtype: attribute type
897 */
898static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
899{
900 return nla_put(skb, attrtype, 0, NULL);
901}
902
903/**
904 * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
905 * @skb: socket buffer to add attribute to
906 * @attrtype: attribute type
907 * @jiffies: number of msecs in jiffies
908 */
909static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
910 unsigned long jiffies)
911{
912 u64 tmp = jiffies_to_msecs(jiffies);
913 return nla_put(skb, attrtype, sizeof(u64), &tmp);
914}
915
916/**
917 * nla_get_u32 - return payload of u32 attribute
918 * @nla: u32 netlink attribute
919 */
920static inline u32 nla_get_u32(const struct nlattr *nla)
921{
922 return *(u32 *) nla_data(nla);
923}
924
925/**
926 * nla_get_be32 - return payload of __be32 attribute
927 * @nla: __be32 netlink attribute
928 */
929static inline __be32 nla_get_be32(const struct nlattr *nla)
930{
931 return *(__be32 *) nla_data(nla);
932}
933
934/**
935 * nla_get_u16 - return payload of u16 attribute
936 * @nla: u16 netlink attribute
937 */
938static inline u16 nla_get_u16(const struct nlattr *nla)
939{
940 return *(u16 *) nla_data(nla);
941}
942
943/**
944 * nla_get_be16 - return payload of __be16 attribute
945 * @nla: __be16 netlink attribute
946 */
947static inline __be16 nla_get_be16(const struct nlattr *nla)
948{
949 return *(__be16 *) nla_data(nla);
950}
951
952/**
953 * nla_get_le16 - return payload of __le16 attribute
954 * @nla: __le16 netlink attribute
955 */
956static inline __le16 nla_get_le16(const struct nlattr *nla)
957{
958 return *(__le16 *) nla_data(nla);
959}
960
961/**
962 * nla_get_u8 - return payload of u8 attribute
963 * @nla: u8 netlink attribute
964 */
965static inline u8 nla_get_u8(const struct nlattr *nla)
966{
967 return *(u8 *) nla_data(nla);
968}
969
970/**
971 * nla_get_u64 - return payload of u64 attribute
972 * @nla: u64 netlink attribute
973 */
974static inline u64 nla_get_u64(const struct nlattr *nla)
975{
976 u64 tmp;
977
978 nla_memcpy(&tmp, nla, sizeof(tmp));
979
980 return tmp;
981}
982
983/**
984 * nla_get_be64 - return payload of __be64 attribute
985 * @nla: __be64 netlink attribute
986 */
987static inline __be64 nla_get_be64(const struct nlattr *nla)
988{
989 __be64 tmp;
990
991 nla_memcpy(&tmp, nla, sizeof(tmp));
992
993 return tmp;
994}
995
996/**
997 * nla_get_flag - return payload of flag attribute
998 * @nla: flag netlink attribute
999 */
1000static inline int nla_get_flag(const struct nlattr *nla)
1001{
1002 return !!nla;
1003}
1004
1005/**
1006 * nla_get_msecs - return payload of msecs attribute
1007 * @nla: msecs netlink attribute
1008 *
1009 * Returns the number of milliseconds in jiffies.
1010 */
1011static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1012{
1013 u64 msecs = nla_get_u64(nla);
1014
1015 return msecs_to_jiffies((unsigned long) msecs);
1016}
1017
1018/**
1019 * nla_nest_start - Start a new level of nested attributes
1020 * @skb: socket buffer to add attributes to
1021 * @attrtype: attribute type of container
1022 *
1023 * Returns the container attribute
1024 */
1025static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1026{
1027 struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1028
1029 if (nla_put(skb, attrtype, 0, NULL) < 0)
1030 return NULL;
1031
1032 return start;
1033}
1034
1035/**
1036 * nla_nest_end - Finalize nesting of attributes
1037 * @skb: socket buffer the attributes are stored in
1038 * @start: container attribute
1039 *
1040 * Corrects the container attribute header to include the all
1041 * appeneded attributes.
1042 *
1043 * Returns the total data length of the skb.
1044 */
1045static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1046{
1047 start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1048 return skb->len;
1049}
1050
1051/**
1052 * nla_nest_cancel - Cancel nesting of attributes
1053 * @skb: socket buffer the message is stored in
1054 * @start: container attribute
1055 *
1056 * Removes the container attribute and including all nested
1057 * attributes. Returns -EMSGSIZE
1058 */
1059static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1060{
1061 nlmsg_trim(skb, start);
1062}
1063
1064/**
1065 * nla_validate_nested - Validate a stream of nested attributes
1066 * @start: container attribute
1067 * @maxtype: maximum attribute type to be expected
1068 * @policy: validation policy
1069 *
1070 * Validates all attributes in the nested attribute stream against the
1071 * specified policy. Attributes with a type exceeding maxtype will be
1072 * ignored. See documenation of struct nla_policy for more details.
1073 *
1074 * Returns 0 on success or a negative error code.
1075 */
1076static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1077 const struct nla_policy *policy)
1078{
1079 return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1080}
1081
1082/**
1083 * nla_for_each_attr - iterate over a stream of attributes
1084 * @pos: loop counter, set to current attribute
1085 * @head: head of attribute stream
1086 * @len: length of attribute stream
1087 * @rem: initialized to len, holds bytes currently remaining in stream
1088 */
1089#define nla_for_each_attr(pos, head, len, rem) \
1090 for (pos = head, rem = len; \
1091 nla_ok(pos, rem); \
1092 pos = nla_next(pos, &(rem)))
1093
1094/**
1095 * nla_for_each_nested - iterate over nested attributes
1096 * @pos: loop counter, set to current attribute
1097 * @nla: attribute containing the nested attributes
1098 * @rem: initialized to len, holds bytes currently remaining in stream
1099 */
1100#define nla_for_each_nested(pos, nla, rem) \
1101 nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1102
1103#endif