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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() finanlize 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 struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
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(struct nlattr *head, int len, int maxtype,
229 const struct nla_policy *policy);
230extern int nla_parse(struct nlattr *tb[], int maxtype,
231 struct nlattr *head, int len,
232 const struct nla_policy *policy);
233extern struct nlattr * nla_find(struct nlattr *head, int len, int attrtype);
234extern size_t nla_strlcpy(char *dst, const struct nlattr *nla,
235 size_t dstsize);
236extern int nla_memcpy(void *dest, struct nlattr *src, int count);
237extern int nla_memcmp(const struct nlattr *nla, const void *data,
238 size_t size);
239extern int nla_strcmp(const struct nlattr *nla, const char *str);
240extern struct nlattr * __nla_reserve(struct sk_buff *skb, int attrtype,
241 int attrlen);
242extern void * __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
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 void __nla_put(struct sk_buff *skb, int attrtype,
247 int attrlen, const void *data);
248extern void __nla_put_nohdr(struct sk_buff *skb, int attrlen,
249 const void *data);
250extern int nla_put(struct sk_buff *skb, int attrtype,
251 int attrlen, const void *data);
252extern int nla_put_nohdr(struct sk_buff *skb, int attrlen,
253 const void *data);
254extern int nla_append(struct sk_buff *skb, int attrlen,
255 const void *data);
256
257/**************************************************************************
258 * Netlink Messages
259 **************************************************************************/
260
261/**
262 * nlmsg_msg_size - length of netlink message not including padding
263 * @payload: length of message payload
264 */
265static inline int nlmsg_msg_size(int payload)
266{
267 return NLMSG_HDRLEN + payload;
268}
269
270/**
271 * nlmsg_total_size - length of netlink message including padding
272 * @payload: length of message payload
273 */
274static inline int nlmsg_total_size(int payload)
275{
276 return NLMSG_ALIGN(nlmsg_msg_size(payload));
277}
278
279/**
280 * nlmsg_padlen - length of padding at the message's tail
281 * @payload: length of message payload
282 */
283static inline int nlmsg_padlen(int payload)
284{
285 return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
286}
287
288/**
289 * nlmsg_data - head of message payload
290 * @nlh: netlink messsage header
291 */
292static inline void *nlmsg_data(const struct nlmsghdr *nlh)
293{
294 return (unsigned char *) nlh + NLMSG_HDRLEN;
295}
296
297/**
298 * nlmsg_len - length of message payload
299 * @nlh: netlink message header
300 */
301static inline int nlmsg_len(const struct nlmsghdr *nlh)
302{
303 return nlh->nlmsg_len - NLMSG_HDRLEN;
304}
305
306/**
307 * nlmsg_attrdata - head of attributes data
308 * @nlh: netlink message header
309 * @hdrlen: length of family specific header
310 */
311static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
312 int hdrlen)
313{
314 unsigned char *data = nlmsg_data(nlh);
315 return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
316}
317
318/**
319 * nlmsg_attrlen - length of attributes data
320 * @nlh: netlink message header
321 * @hdrlen: length of family specific header
322 */
323static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
324{
325 return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
326}
327
328/**
329 * nlmsg_ok - check if the netlink message fits into the remaining bytes
330 * @nlh: netlink message header
331 * @remaining: number of bytes remaining in message stream
332 */
333static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
334{
335 return (remaining >= sizeof(struct nlmsghdr) &&
336 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
337 nlh->nlmsg_len <= remaining);
338}
339
340/**
341 * nlmsg_next - next netlink message in message stream
342 * @nlh: netlink message header
343 * @remaining: number of bytes remaining in message stream
344 *
345 * Returns the next netlink message in the message stream and
346 * decrements remaining by the size of the current message.
347 */
348static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
349{
350 int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
351
352 *remaining -= totlen;
353
354 return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
355}
356
357/**
358 * nlmsg_parse - parse attributes of a netlink message
359 * @nlh: netlink message header
360 * @hdrlen: length of family specific header
361 * @tb: destination array with maxtype+1 elements
362 * @maxtype: maximum attribute type to be expected
363 * @policy: validation policy
364 *
365 * See nla_parse()
366 */
367static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
368 struct nlattr *tb[], int maxtype,
369 const struct nla_policy *policy)
370{
371 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
372 return -EINVAL;
373
374 return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
375 nlmsg_attrlen(nlh, hdrlen), policy);
376}
377
378/**
379 * nlmsg_find_attr - find a specific attribute in a netlink message
380 * @nlh: netlink message header
381 * @hdrlen: length of familiy specific header
382 * @attrtype: type of attribute to look for
383 *
384 * Returns the first attribute which matches the specified type.
385 */
386static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
387 int hdrlen, int attrtype)
388{
389 return nla_find(nlmsg_attrdata(nlh, hdrlen),
390 nlmsg_attrlen(nlh, hdrlen), attrtype);
391}
392
393/**
394 * nlmsg_validate - validate a netlink message including attributes
395 * @nlh: netlinket message header
396 * @hdrlen: length of familiy specific header
397 * @maxtype: maximum attribute type to be expected
398 * @policy: validation policy
399 */
400static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
401 const struct nla_policy *policy)
402{
403 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
404 return -EINVAL;
405
406 return nla_validate(nlmsg_attrdata(nlh, hdrlen),
407 nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
408}
409
410/**
411 * nlmsg_report - need to report back to application?
412 * @nlh: netlink message header
413 *
414 * Returns 1 if a report back to the application is requested.
415 */
416static inline int nlmsg_report(struct nlmsghdr *nlh)
417{
418 return !!(nlh->nlmsg_flags & NLM_F_ECHO);
419}
420
421/**
422 * nlmsg_for_each_attr - iterate over a stream of attributes
423 * @pos: loop counter, set to current attribute
424 * @nlh: netlink message header
425 * @hdrlen: length of familiy specific header
426 * @rem: initialized to len, holds bytes currently remaining in stream
427 */
428#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
429 nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
430 nlmsg_attrlen(nlh, hdrlen), rem)
431
432#if 0
433/* FIXME: Enable once all users have been converted */
434
435/**
436 * __nlmsg_put - Add a new netlink message to an skb
437 * @skb: socket buffer to store message in
438 * @pid: netlink process id
439 * @seq: sequence number of message
440 * @type: message type
441 * @payload: length of message payload
442 * @flags: message flags
443 *
444 * The caller is responsible to ensure that the skb provides enough
445 * tailroom for both the netlink header and payload.
446 */
447static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
448 u32 seq, int type, int payload,
449 int flags)
450{
451 struct nlmsghdr *nlh;
452
453 nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
454 nlh->nlmsg_type = type;
455 nlh->nlmsg_len = nlmsg_msg_size(payload);
456 nlh->nlmsg_flags = flags;
457 nlh->nlmsg_pid = pid;
458 nlh->nlmsg_seq = seq;
459
460 memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
461 nlmsg_padlen(payload));
462
463 return nlh;
464}
465#endif
466
467/**
468 * nlmsg_put - Add a new netlink message to an skb
469 * @skb: socket buffer to store message in
470 * @pid: netlink process id
471 * @seq: sequence number of message
472 * @type: message type
473 * @payload: length of message payload
474 * @flags: message flags
475 *
476 * Returns NULL if the tailroom of the skb is insufficient to store
477 * the message header and payload.
478 */
479static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
480 int type, int payload, int flags)
481{
482 if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
483 return NULL;
484
485 return __nlmsg_put(skb, pid, seq, type, payload, flags);
486}
487
488/**
489 * nlmsg_put_answer - Add a new callback based netlink message to an skb
490 * @skb: socket buffer to store message in
491 * @cb: netlink callback
492 * @type: message type
493 * @payload: length of message payload
494 * @flags: message flags
495 *
496 * Returns NULL if the tailroom of the skb is insufficient to store
497 * the message header and payload.
498 */
499static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
500 struct netlink_callback *cb,
501 int type, int payload,
502 int flags)
503{
504 return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
505 type, payload, flags);
506}
507
508/**
509 * nlmsg_new - Allocate a new netlink message
510 * @payload: size of the message payload
511 * @flags: the type of memory to allocate.
512 *
513 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
514 * and a good default is needed.
515 */
516static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
517{
518 return alloc_skb(nlmsg_total_size(payload), flags);
519}
520
521/**
522 * nlmsg_end - Finalize a netlink message
523 * @skb: socket buffer the message is stored in
524 * @nlh: netlink message header
525 *
526 * Corrects the netlink message header to include the appeneded
527 * attributes. Only necessary if attributes have been added to
528 * the message.
529 *
530 * Returns the total data length of the skb.
531 */
532static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
533{
534 nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
535
536 return skb->len;
537}
538
539/**
540 * nlmsg_get_pos - return current position in netlink message
541 * @skb: socket buffer the message is stored in
542 *
543 * Returns a pointer to the current tail of the message.
544 */
545static inline void *nlmsg_get_pos(struct sk_buff *skb)
546{
547 return skb_tail_pointer(skb);
548}
549
550/**
551 * nlmsg_trim - Trim message to a mark
552 * @skb: socket buffer the message is stored in
553 * @mark: mark to trim to
554 *
555 * Trims the message to the provided mark.
556 */
557static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
558{
559 if (mark)
560 skb_trim(skb, (unsigned char *) mark - skb->data);
561}
562
563/**
564 * nlmsg_cancel - Cancel construction of a netlink message
565 * @skb: socket buffer the message is stored in
566 * @nlh: netlink message header
567 *
568 * Removes the complete netlink message including all
569 * attributes from the socket buffer again.
570 */
571static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
572{
573 nlmsg_trim(skb, nlh);
574}
575
576/**
577 * nlmsg_free - free a netlink message
578 * @skb: socket buffer of netlink message
579 */
580static inline void nlmsg_free(struct sk_buff *skb)
581{
582 kfree_skb(skb);
583}
584
585/**
586 * nlmsg_multicast - multicast a netlink message
587 * @sk: netlink socket to spread messages to
588 * @skb: netlink message as socket buffer
589 * @pid: own netlink pid to avoid sending to yourself
590 * @group: multicast group id
591 * @flags: allocation flags
592 */
593static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
594 u32 pid, unsigned int group, gfp_t flags)
595{
596 int err;
597
598 NETLINK_CB(skb).dst_group = group;
599
600 err = netlink_broadcast(sk, skb, pid, group, flags);
601 if (err > 0)
602 err = 0;
603
604 return err;
605}
606
607/**
608 * nlmsg_unicast - unicast a netlink message
609 * @sk: netlink socket to spread message to
610 * @skb: netlink message as socket buffer
611 * @pid: netlink pid of the destination socket
612 */
613static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
614{
615 int err;
616
617 err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
618 if (err > 0)
619 err = 0;
620
621 return err;
622}
623
624/**
625 * nlmsg_for_each_msg - iterate over a stream of messages
626 * @pos: loop counter, set to current message
627 * @head: head of message stream
628 * @len: length of message stream
629 * @rem: initialized to len, holds bytes currently remaining in stream
630 */
631#define nlmsg_for_each_msg(pos, head, len, rem) \
632 for (pos = head, rem = len; \
633 nlmsg_ok(pos, rem); \
634 pos = nlmsg_next(pos, &(rem)))
635
636/**************************************************************************
637 * Netlink Attributes
638 **************************************************************************/
639
640/**
641 * nla_attr_size - length of attribute not including padding
642 * @payload: length of payload
643 */
644static inline int nla_attr_size(int payload)
645{
646 return NLA_HDRLEN + payload;
647}
648
649/**
650 * nla_total_size - total length of attribute including padding
651 * @payload: length of payload
652 */
653static inline int nla_total_size(int payload)
654{
655 return NLA_ALIGN(nla_attr_size(payload));
656}
657
658/**
659 * nla_padlen - length of padding at the tail of attribute
660 * @payload: length of payload
661 */
662static inline int nla_padlen(int payload)
663{
664 return nla_total_size(payload) - nla_attr_size(payload);
665}
666
667/**
668 * nla_type - attribute type
669 * @nla: netlink attribute
670 */
671static inline int nla_type(const struct nlattr *nla)
672{
673 return nla->nla_type & NLA_TYPE_MASK;
674}
675
676/**
677 * nla_data - head of payload
678 * @nla: netlink attribute
679 */
680static inline void *nla_data(const struct nlattr *nla)
681{
682 return (char *) nla + NLA_HDRLEN;
683}
684
685/**
686 * nla_len - length of payload
687 * @nla: netlink attribute
688 */
689static inline int nla_len(const struct nlattr *nla)
690{
691 return nla->nla_len - NLA_HDRLEN;
692}
693
694/**
695 * nla_ok - check if the netlink attribute fits into the remaining bytes
696 * @nla: netlink attribute
697 * @remaining: number of bytes remaining in attribute stream
698 */
699static inline int nla_ok(const struct nlattr *nla, int remaining)
700{
701 return remaining >= (int) sizeof(*nla) &&
702 nla->nla_len >= sizeof(*nla) &&
703 nla->nla_len <= remaining;
704}
705
706/**
707 * nla_next - next netlink attribute in attribute stream
708 * @nla: netlink attribute
709 * @remaining: number of bytes remaining in attribute stream
710 *
711 * Returns the next netlink attribute in the attribute stream and
712 * decrements remaining by the size of the current attribute.
713 */
714static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
715{
716 int totlen = NLA_ALIGN(nla->nla_len);
717
718 *remaining -= totlen;
719 return (struct nlattr *) ((char *) nla + totlen);
720}
721
722/**
723 * nla_find_nested - find attribute in a set of nested attributes
724 * @nla: attribute containing the nested attributes
725 * @attrtype: type of attribute to look for
726 *
727 * Returns the first attribute which matches the specified type.
728 */
729static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
730{
731 return nla_find(nla_data(nla), nla_len(nla), attrtype);
732}
733
734/**
735 * nla_parse_nested - parse nested attributes
736 * @tb: destination array with maxtype+1 elements
737 * @maxtype: maximum attribute type to be expected
738 * @nla: attribute containing the nested attributes
739 * @policy: validation policy
740 *
741 * See nla_parse()
742 */
743static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
744 struct nlattr *nla,
745 const struct nla_policy *policy)
746{
747 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
748}
749
750/**
751 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
752 * @skb: socket buffer to add attribute to
753 * @attrtype: attribute type
754 * @value: numeric value
755 */
756static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
757{
758 return nla_put(skb, attrtype, sizeof(u8), &value);
759}
760
761/**
762 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
763 * @skb: socket buffer to add attribute to
764 * @attrtype: attribute type
765 * @value: numeric value
766 */
767static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
768{
769 return nla_put(skb, attrtype, sizeof(u16), &value);
770}
771
772/**
773 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
774 * @skb: socket buffer to add attribute to
775 * @attrtype: attribute type
776 * @value: numeric value
777 */
778static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
779{
780 return nla_put(skb, attrtype, sizeof(u32), &value);
781}
782
783/**
784 * nla_put_64 - Add a u64 netlink attribute to a socket buffer
785 * @skb: socket buffer to add attribute to
786 * @attrtype: attribute type
787 * @value: numeric value
788 */
789static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
790{
791 return nla_put(skb, attrtype, sizeof(u64), &value);
792}
793
794/**
795 * nla_put_string - Add a string netlink attribute to a socket buffer
796 * @skb: socket buffer to add attribute to
797 * @attrtype: attribute type
798 * @str: NUL terminated string
799 */
800static inline int nla_put_string(struct sk_buff *skb, int attrtype,
801 const char *str)
802{
803 return nla_put(skb, attrtype, strlen(str) + 1, str);
804}
805
806/**
807 * nla_put_flag - Add a flag netlink attribute to a socket buffer
808 * @skb: socket buffer to add attribute to
809 * @attrtype: attribute type
810 */
811static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
812{
813 return nla_put(skb, attrtype, 0, NULL);
814}
815
816/**
817 * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
818 * @skb: socket buffer to add attribute to
819 * @attrtype: attribute type
820 * @jiffies: number of msecs in jiffies
821 */
822static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
823 unsigned long jiffies)
824{
825 u64 tmp = jiffies_to_msecs(jiffies);
826 return nla_put(skb, attrtype, sizeof(u64), &tmp);
827}
828
829#define NLA_PUT(skb, attrtype, attrlen, data) \
830 do { \
831 if (unlikely(nla_put(skb, attrtype, attrlen, data) < 0)) \
832 goto nla_put_failure; \
833 } while(0)
834
835#define NLA_PUT_TYPE(skb, type, attrtype, value) \
836 do { \
837 type __tmp = value; \
838 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
839 } while(0)
840
841#define NLA_PUT_U8(skb, attrtype, value) \
842 NLA_PUT_TYPE(skb, u8, attrtype, value)
843
844#define NLA_PUT_U16(skb, attrtype, value) \
845 NLA_PUT_TYPE(skb, u16, attrtype, value)
846
847#define NLA_PUT_LE16(skb, attrtype, value) \
848 NLA_PUT_TYPE(skb, __le16, attrtype, value)
849
850#define NLA_PUT_BE16(skb, attrtype, value) \
851 NLA_PUT_TYPE(skb, __be16, attrtype, value)
852
853#define NLA_PUT_U32(skb, attrtype, value) \
854 NLA_PUT_TYPE(skb, u32, attrtype, value)
855
856#define NLA_PUT_BE32(skb, attrtype, value) \
857 NLA_PUT_TYPE(skb, __be32, attrtype, value)
858
859#define NLA_PUT_U64(skb, attrtype, value) \
860 NLA_PUT_TYPE(skb, u64, attrtype, value)
861
862#define NLA_PUT_BE64(skb, attrtype, value) \
863 NLA_PUT_TYPE(skb, __be64, attrtype, value)
864
865#define NLA_PUT_STRING(skb, attrtype, value) \
866 NLA_PUT(skb, attrtype, strlen(value) + 1, value)
867
868#define NLA_PUT_FLAG(skb, attrtype) \
869 NLA_PUT(skb, attrtype, 0, NULL)
870
871#define NLA_PUT_MSECS(skb, attrtype, jiffies) \
872 NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
873
874/**
875 * nla_get_u32 - return payload of u32 attribute
876 * @nla: u32 netlink attribute
877 */
878static inline u32 nla_get_u32(struct nlattr *nla)
879{
880 return *(u32 *) nla_data(nla);
881}
882
883/**
884 * nla_get_be32 - return payload of __be32 attribute
885 * @nla: __be32 netlink attribute
886 */
887static inline __be32 nla_get_be32(struct nlattr *nla)
888{
889 return *(__be32 *) nla_data(nla);
890}
891
892/**
893 * nla_get_u16 - return payload of u16 attribute
894 * @nla: u16 netlink attribute
895 */
896static inline u16 nla_get_u16(struct nlattr *nla)
897{
898 return *(u16 *) nla_data(nla);
899}
900
901/**
902 * nla_get_be16 - return payload of __be16 attribute
903 * @nla: __be16 netlink attribute
904 */
905static inline __be16 nla_get_be16(struct nlattr *nla)
906{
907 return *(__be16 *) nla_data(nla);
908}
909
910/**
911 * nla_get_le16 - return payload of __le16 attribute
912 * @nla: __le16 netlink attribute
913 */
914static inline __le16 nla_get_le16(struct nlattr *nla)
915{
916 return *(__le16 *) nla_data(nla);
917}
918
919/**
920 * nla_get_u8 - return payload of u8 attribute
921 * @nla: u8 netlink attribute
922 */
923static inline u8 nla_get_u8(struct nlattr *nla)
924{
925 return *(u8 *) nla_data(nla);
926}
927
928/**
929 * nla_get_u64 - return payload of u64 attribute
930 * @nla: u64 netlink attribute
931 */
932static inline u64 nla_get_u64(struct nlattr *nla)
933{
934 u64 tmp;
935
936 nla_memcpy(&tmp, nla, sizeof(tmp));
937
938 return tmp;
939}
940
941/**
942 * nla_get_flag - return payload of flag attribute
943 * @nla: flag netlink attribute
944 */
945static inline int nla_get_flag(struct nlattr *nla)
946{
947 return !!nla;
948}
949
950/**
951 * nla_get_msecs - return payload of msecs attribute
952 * @nla: msecs netlink attribute
953 *
954 * Returns the number of milliseconds in jiffies.
955 */
956static inline unsigned long nla_get_msecs(struct nlattr *nla)
957{
958 u64 msecs = nla_get_u64(nla);
959
960 return msecs_to_jiffies((unsigned long) msecs);
961}
962
963/**
964 * nla_nest_start - Start a new level of nested attributes
965 * @skb: socket buffer to add attributes to
966 * @attrtype: attribute type of container
967 *
968 * Returns the container attribute
969 */
970static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
971{
972 struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
973
974 if (nla_put(skb, attrtype, 0, NULL) < 0)
975 return NULL;
976
977 return start;
978}
979
980/**
981 * nla_nest_end - Finalize nesting of attributes
982 * @skb: socket buffer the attributes are stored in
983 * @start: container attribute
984 *
985 * Corrects the container attribute header to include the all
986 * appeneded attributes.
987 *
988 * Returns the total data length of the skb.
989 */
990static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
991{
992 start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
993 return skb->len;
994}
995
996/**
997 * nla_nest_cancel - Cancel nesting of attributes
998 * @skb: socket buffer the message is stored in
999 * @start: container attribute
1000 *
1001 * Removes the container attribute and including all nested
1002 * attributes. Returns -EMSGSIZE
1003 */
1004static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1005{
1006 nlmsg_trim(skb, start);
1007}
1008
1009/**
1010 * nla_validate_nested - Validate a stream of nested attributes
1011 * @start: container attribute
1012 * @maxtype: maximum attribute type to be expected
1013 * @policy: validation policy
1014 *
1015 * Validates all attributes in the nested attribute stream against the
1016 * specified policy. Attributes with a type exceeding maxtype will be
1017 * ignored. See documenation of struct nla_policy for more details.
1018 *
1019 * Returns 0 on success or a negative error code.
1020 */
1021static inline int nla_validate_nested(struct nlattr *start, int maxtype,
1022 const struct nla_policy *policy)
1023{
1024 return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1025}
1026
1027/**
1028 * nla_for_each_attr - iterate over a stream of attributes
1029 * @pos: loop counter, set to current attribute
1030 * @head: head of attribute stream
1031 * @len: length of attribute stream
1032 * @rem: initialized to len, holds bytes currently remaining in stream
1033 */
1034#define nla_for_each_attr(pos, head, len, rem) \
1035 for (pos = head, rem = len; \
1036 nla_ok(pos, rem); \
1037 pos = nla_next(pos, &(rem)))
1038
1039/**
1040 * nla_for_each_nested - iterate over nested attributes
1041 * @pos: loop counter, set to current attribute
1042 * @nla: attribute containing the nested attributes
1043 * @rem: initialized to len, holds bytes currently remaining in stream
1044 */
1045#define nla_for_each_nested(pos, nla, rem) \
1046 nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1047
1048#endif