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TOMOYO Linux Cross Reference
Linux/include/net/netlink.h

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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_s8(skb, type, value)       add s8 attribute to skb
102  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
103  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
104  *   nla_put_s64(skb, type, value)      add s64 attribute to skb
105  *   nla_put_string(skb, type, str)     add string attribute to skb
106  *   nla_put_flag(skb, type)            add flag attribute to skb
107  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
108  *
109  * Nested Attributes Construction:
110  *   nla_nest_start(skb, type)          start a nested attribute
111  *   nla_nest_end(skb, nla)             finalize a nested attribute
112  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
113  *
114  * Attribute Length Calculations:
115  *   nla_attr_size(payload)             length of attribute w/o padding
116  *   nla_total_size(payload)            length of attribute w/ padding
117  *   nla_padlen(payload)                length of padding
118  *
119  * Attribute Payload Access:
120  *   nla_data(nla)                      head of attribute payload
121  *   nla_len(nla)                       length of attribute payload
122  *
123  * Attribute Payload Access for Basic Types:
124  *   nla_get_u8(nla)                    get payload for a u8 attribute
125  *   nla_get_u16(nla)                   get payload for a u16 attribute
126  *   nla_get_u32(nla)                   get payload for a u32 attribute
127  *   nla_get_u64(nla)                   get payload for a u64 attribute
128  *   nla_get_s8(nla)                    get payload for a s8 attribute
129  *   nla_get_s16(nla)                   get payload for a s16 attribute
130  *   nla_get_s32(nla)                   get payload for a s32 attribute
131  *   nla_get_s64(nla)                   get payload for a s64 attribute
132  *   nla_get_flag(nla)                  return 1 if flag is true
133  *   nla_get_msecs(nla)                 get payload for a msecs attribute
134  *
135  * Attribute Misc:
136  *   nla_memcpy(dest, nla, count)       copy attribute into memory
137  *   nla_memcmp(nla, data, size)        compare attribute with memory area
138  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
139  *   nla_strcmp(nla, str)               compare attribute with string
140  *
141  * Attribute Parsing:
142  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
143  *   nla_next(nla, remaining)           get next netlink attribute
144  *   nla_validate()                     validate a stream of attributes
145  *   nla_validate_nested()              validate a stream of nested attributes
146  *   nla_find()                         find attribute in stream of attributes
147  *   nla_find_nested()                  find attribute in nested attributes
148  *   nla_parse()                        parse and validate stream of attrs
149  *   nla_parse_nested()                 parse nested attribuets
150  *   nla_for_each_attr()                loop over all attributes
151  *   nla_for_each_nested()              loop over the nested attributes
152  *=========================================================================
153  */
154 
155  /**
156   * Standard attribute types to specify validation policy
157   */
158 enum {
159         NLA_UNSPEC,
160         NLA_U8,
161         NLA_U16,
162         NLA_U32,
163         NLA_U64,
164         NLA_STRING,
165         NLA_FLAG,
166         NLA_MSECS,
167         NLA_NESTED,
168         NLA_NESTED_COMPAT,
169         NLA_NUL_STRING,
170         NLA_BINARY,
171         NLA_S8,
172         NLA_S16,
173         NLA_S32,
174         NLA_S64,
175         __NLA_TYPE_MAX,
176 };
177 
178 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
179 
180 /**
181  * struct nla_policy - attribute validation policy
182  * @type: Type of attribute or NLA_UNSPEC
183  * @len: Type specific length of payload
184  *
185  * Policies are defined as arrays of this struct, the array must be
186  * accessible by attribute type up to the highest identifier to be expected.
187  *
188  * Meaning of `len' field:
189  *    NLA_STRING           Maximum length of string
190  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
191  *    NLA_FLAG             Unused
192  *    NLA_BINARY           Maximum length of attribute payload
193  *    NLA_NESTED           Don't use `len' field -- length verification is
194  *                         done by checking len of nested header (or empty)
195  *    NLA_NESTED_COMPAT    Minimum length of structure payload
196  *    NLA_U8, NLA_U16,
197  *    NLA_U32, NLA_U64,
198  *    NLA_S8, NLA_S16,
199  *    NLA_S32, NLA_S64,
200  *    NLA_MSECS            Leaving the length field zero will verify the
201  *                         given type fits, using it verifies minimum length
202  *                         just like "All other"
203  *    All other            Minimum length of attribute payload
204  *
205  * Example:
206  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
207  *      [ATTR_FOO] = { .type = NLA_U16 },
208  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
209  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
210  * };
211  */
212 struct nla_policy {
213         u16             type;
214         u16             len;
215 };
216 
217 /**
218  * struct nl_info - netlink source information
219  * @nlh: Netlink message header of original request
220  * @portid: Netlink PORTID of requesting application
221  */
222 struct nl_info {
223         struct nlmsghdr         *nlh;
224         struct net              *nl_net;
225         u32                     portid;
226 };
227 
228 int netlink_rcv_skb(struct sk_buff *skb,
229                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
230 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
231                  unsigned int group, int report, gfp_t flags);
232 
233 int nla_validate(const struct nlattr *head, int len, int maxtype,
234                  const struct nla_policy *policy);
235 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
236               int len, const struct nla_policy *policy);
237 int nla_policy_len(const struct nla_policy *, int);
238 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
239 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
240 int nla_memcpy(void *dest, const struct nlattr *src, int count);
241 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
242 int nla_strcmp(const struct nlattr *nla, const char *str);
243 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
244 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
245 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
246 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
247 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
248                const void *data);
249 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
250 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
251 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
252 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
253 
254 /**************************************************************************
255  * Netlink Messages
256  **************************************************************************/
257 
258 /**
259  * nlmsg_msg_size - length of netlink message not including padding
260  * @payload: length of message payload
261  */
262 static inline int nlmsg_msg_size(int payload)
263 {
264         return NLMSG_HDRLEN + payload;
265 }
266 
267 /**
268  * nlmsg_total_size - length of netlink message including padding
269  * @payload: length of message payload
270  */
271 static inline int nlmsg_total_size(int payload)
272 {
273         return NLMSG_ALIGN(nlmsg_msg_size(payload));
274 }
275 
276 /**
277  * nlmsg_padlen - length of padding at the message's tail
278  * @payload: length of message payload
279  */
280 static inline int nlmsg_padlen(int payload)
281 {
282         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
283 }
284 
285 /**
286  * nlmsg_data - head of message payload
287  * @nlh: netlink message header
288  */
289 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
290 {
291         return (unsigned char *) nlh + NLMSG_HDRLEN;
292 }
293 
294 /**
295  * nlmsg_len - length of message payload
296  * @nlh: netlink message header
297  */
298 static inline int nlmsg_len(const struct nlmsghdr *nlh)
299 {
300         return nlh->nlmsg_len - NLMSG_HDRLEN;
301 }
302 
303 /**
304  * nlmsg_attrdata - head of attributes data
305  * @nlh: netlink message header
306  * @hdrlen: length of family specific header
307  */
308 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
309                                             int hdrlen)
310 {
311         unsigned char *data = nlmsg_data(nlh);
312         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
313 }
314 
315 /**
316  * nlmsg_attrlen - length of attributes data
317  * @nlh: netlink message header
318  * @hdrlen: length of family specific header
319  */
320 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
321 {
322         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
323 }
324 
325 /**
326  * nlmsg_ok - check if the netlink message fits into the remaining bytes
327  * @nlh: netlink message header
328  * @remaining: number of bytes remaining in message stream
329  */
330 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
331 {
332         return (remaining >= (int) sizeof(struct nlmsghdr) &&
333                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
334                 nlh->nlmsg_len <= remaining);
335 }
336 
337 /**
338  * nlmsg_next - next netlink message in message stream
339  * @nlh: netlink message header
340  * @remaining: number of bytes remaining in message stream
341  *
342  * Returns the next netlink message in the message stream and
343  * decrements remaining by the size of the current message.
344  */
345 static inline struct nlmsghdr *
346 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
347 {
348         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
349 
350         *remaining -= totlen;
351 
352         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
353 }
354 
355 /**
356  * nlmsg_parse - parse attributes of a netlink message
357  * @nlh: netlink message header
358  * @hdrlen: length of family specific header
359  * @tb: destination array with maxtype+1 elements
360  * @maxtype: maximum attribute type to be expected
361  * @policy: validation policy
362  *
363  * See nla_parse()
364  */
365 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
366                               struct nlattr *tb[], int maxtype,
367                               const struct nla_policy *policy)
368 {
369         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
370                 return -EINVAL;
371 
372         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
373                          nlmsg_attrlen(nlh, hdrlen), policy);
374 }
375 
376 /**
377  * nlmsg_find_attr - find a specific attribute in a netlink message
378  * @nlh: netlink message header
379  * @hdrlen: length of familiy specific header
380  * @attrtype: type of attribute to look for
381  *
382  * Returns the first attribute which matches the specified type.
383  */
384 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
385                                              int hdrlen, int attrtype)
386 {
387         return nla_find(nlmsg_attrdata(nlh, hdrlen),
388                         nlmsg_attrlen(nlh, hdrlen), attrtype);
389 }
390 
391 /**
392  * nlmsg_validate - validate a netlink message including attributes
393  * @nlh: netlinket message header
394  * @hdrlen: length of familiy specific header
395  * @maxtype: maximum attribute type to be expected
396  * @policy: validation policy
397  */
398 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
399                                  int hdrlen, int maxtype,
400                                  const struct nla_policy *policy)
401 {
402         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
403                 return -EINVAL;
404 
405         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
406                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
407 }
408 
409 /**
410  * nlmsg_report - need to report back to application?
411  * @nlh: netlink message header
412  *
413  * Returns 1 if a report back to the application is requested.
414  */
415 static inline int nlmsg_report(const struct nlmsghdr *nlh)
416 {
417         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
418 }
419 
420 /**
421  * nlmsg_for_each_attr - iterate over a stream of attributes
422  * @pos: loop counter, set to current attribute
423  * @nlh: netlink message header
424  * @hdrlen: length of familiy specific header
425  * @rem: initialized to len, holds bytes currently remaining in stream
426  */
427 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
428         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
429                           nlmsg_attrlen(nlh, hdrlen), rem)
430 
431 /**
432  * nlmsg_put - Add a new netlink message to an skb
433  * @skb: socket buffer to store message in
434  * @portid: netlink process id
435  * @seq: sequence number of message
436  * @type: message type
437  * @payload: length of message payload
438  * @flags: message flags
439  *
440  * Returns NULL if the tailroom of the skb is insufficient to store
441  * the message header and payload.
442  */
443 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
444                                          int type, int payload, int flags)
445 {
446         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
447                 return NULL;
448 
449         return __nlmsg_put(skb, portid, seq, type, payload, flags);
450 }
451 
452 /**
453  * nlmsg_put_answer - Add a new callback based netlink message to an skb
454  * @skb: socket buffer to store message in
455  * @cb: netlink callback
456  * @type: message type
457  * @payload: length of message payload
458  * @flags: message flags
459  *
460  * Returns NULL if the tailroom of the skb is insufficient to store
461  * the message header and payload.
462  */
463 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
464                                                 struct netlink_callback *cb,
465                                                 int type, int payload,
466                                                 int flags)
467 {
468         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
469                          type, payload, flags);
470 }
471 
472 /**
473  * nlmsg_new - Allocate a new netlink message
474  * @payload: size of the message payload
475  * @flags: the type of memory to allocate.
476  *
477  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
478  * and a good default is needed.
479  */
480 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
481 {
482         return alloc_skb(nlmsg_total_size(payload), flags);
483 }
484 
485 /**
486  * nlmsg_end - Finalize a netlink message
487  * @skb: socket buffer the message is stored in
488  * @nlh: netlink message header
489  *
490  * Corrects the netlink message header to include the appeneded
491  * attributes. Only necessary if attributes have been added to
492  * the message.
493  *
494  * Returns the total data length of the skb.
495  */
496 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
497 {
498         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
499 
500         return skb->len;
501 }
502 
503 /**
504  * nlmsg_get_pos - return current position in netlink message
505  * @skb: socket buffer the message is stored in
506  *
507  * Returns a pointer to the current tail of the message.
508  */
509 static inline void *nlmsg_get_pos(struct sk_buff *skb)
510 {
511         return skb_tail_pointer(skb);
512 }
513 
514 /**
515  * nlmsg_trim - Trim message to a mark
516  * @skb: socket buffer the message is stored in
517  * @mark: mark to trim to
518  *
519  * Trims the message to the provided mark.
520  */
521 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
522 {
523         if (mark)
524                 skb_trim(skb, (unsigned char *) mark - skb->data);
525 }
526 
527 /**
528  * nlmsg_cancel - Cancel construction of a netlink message
529  * @skb: socket buffer the message is stored in
530  * @nlh: netlink message header
531  *
532  * Removes the complete netlink message including all
533  * attributes from the socket buffer again.
534  */
535 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
536 {
537         nlmsg_trim(skb, nlh);
538 }
539 
540 /**
541  * nlmsg_free - free a netlink message
542  * @skb: socket buffer of netlink message
543  */
544 static inline void nlmsg_free(struct sk_buff *skb)
545 {
546         kfree_skb(skb);
547 }
548 
549 /**
550  * nlmsg_multicast - multicast a netlink message
551  * @sk: netlink socket to spread messages to
552  * @skb: netlink message as socket buffer
553  * @portid: own netlink portid to avoid sending to yourself
554  * @group: multicast group id
555  * @flags: allocation flags
556  */
557 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
558                                   u32 portid, unsigned int group, gfp_t flags)
559 {
560         int err;
561 
562         NETLINK_CB(skb).dst_group = group;
563 
564         err = netlink_broadcast(sk, skb, portid, group, flags);
565         if (err > 0)
566                 err = 0;
567 
568         return err;
569 }
570 
571 /**
572  * nlmsg_unicast - unicast a netlink message
573  * @sk: netlink socket to spread message to
574  * @skb: netlink message as socket buffer
575  * @portid: netlink portid of the destination socket
576  */
577 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
578 {
579         int err;
580 
581         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
582         if (err > 0)
583                 err = 0;
584 
585         return err;
586 }
587 
588 /**
589  * nlmsg_for_each_msg - iterate over a stream of messages
590  * @pos: loop counter, set to current message
591  * @head: head of message stream
592  * @len: length of message stream
593  * @rem: initialized to len, holds bytes currently remaining in stream
594  */
595 #define nlmsg_for_each_msg(pos, head, len, rem) \
596         for (pos = head, rem = len; \
597              nlmsg_ok(pos, rem); \
598              pos = nlmsg_next(pos, &(rem)))
599 
600 /**
601  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
602  * @cb: netlink callback structure that stores the sequence number
603  * @nlh: netlink message header to write the flag to
604  *
605  * This function checks if the sequence (generation) number changed during dump
606  * and if it did, advertises it in the netlink message header.
607  *
608  * The correct way to use it is to set cb->seq to the generation counter when
609  * all locks for dumping have been acquired, and then call this function for
610  * each message that is generated.
611  *
612  * Note that due to initialisation concerns, 0 is an invalid sequence number
613  * and must not be used by code that uses this functionality.
614  */
615 static inline void
616 nl_dump_check_consistent(struct netlink_callback *cb,
617                          struct nlmsghdr *nlh)
618 {
619         if (cb->prev_seq && cb->seq != cb->prev_seq)
620                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
621         cb->prev_seq = cb->seq;
622 }
623 
624 /**************************************************************************
625  * Netlink Attributes
626  **************************************************************************/
627 
628 /**
629  * nla_attr_size - length of attribute not including padding
630  * @payload: length of payload
631  */
632 static inline int nla_attr_size(int payload)
633 {
634         return NLA_HDRLEN + payload;
635 }
636 
637 /**
638  * nla_total_size - total length of attribute including padding
639  * @payload: length of payload
640  */
641 static inline int nla_total_size(int payload)
642 {
643         return NLA_ALIGN(nla_attr_size(payload));
644 }
645 
646 /**
647  * nla_padlen - length of padding at the tail of attribute
648  * @payload: length of payload
649  */
650 static inline int nla_padlen(int payload)
651 {
652         return nla_total_size(payload) - nla_attr_size(payload);
653 }
654 
655 /**
656  * nla_type - attribute type
657  * @nla: netlink attribute
658  */
659 static inline int nla_type(const struct nlattr *nla)
660 {
661         return nla->nla_type & NLA_TYPE_MASK;
662 }
663 
664 /**
665  * nla_data - head of payload
666  * @nla: netlink attribute
667  */
668 static inline void *nla_data(const struct nlattr *nla)
669 {
670         return (char *) nla + NLA_HDRLEN;
671 }
672 
673 /**
674  * nla_len - length of payload
675  * @nla: netlink attribute
676  */
677 static inline int nla_len(const struct nlattr *nla)
678 {
679         return nla->nla_len - NLA_HDRLEN;
680 }
681 
682 /**
683  * nla_ok - check if the netlink attribute fits into the remaining bytes
684  * @nla: netlink attribute
685  * @remaining: number of bytes remaining in attribute stream
686  */
687 static inline int nla_ok(const struct nlattr *nla, int remaining)
688 {
689         return remaining >= (int) sizeof(*nla) &&
690                nla->nla_len >= sizeof(*nla) &&
691                nla->nla_len <= remaining;
692 }
693 
694 /**
695  * nla_next - next netlink attribute in attribute stream
696  * @nla: netlink attribute
697  * @remaining: number of bytes remaining in attribute stream
698  *
699  * Returns the next netlink attribute in the attribute stream and
700  * decrements remaining by the size of the current attribute.
701  */
702 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
703 {
704         int totlen = NLA_ALIGN(nla->nla_len);
705 
706         *remaining -= totlen;
707         return (struct nlattr *) ((char *) nla + totlen);
708 }
709 
710 /**
711  * nla_find_nested - find attribute in a set of nested attributes
712  * @nla: attribute containing the nested attributes
713  * @attrtype: type of attribute to look for
714  *
715  * Returns the first attribute which matches the specified type.
716  */
717 static inline struct nlattr *
718 nla_find_nested(const struct nlattr *nla, int attrtype)
719 {
720         return nla_find(nla_data(nla), nla_len(nla), attrtype);
721 }
722 
723 /**
724  * nla_parse_nested - parse nested attributes
725  * @tb: destination array with maxtype+1 elements
726  * @maxtype: maximum attribute type to be expected
727  * @nla: attribute containing the nested attributes
728  * @policy: validation policy
729  *
730  * See nla_parse()
731  */
732 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
733                                    const struct nlattr *nla,
734                                    const struct nla_policy *policy)
735 {
736         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
737 }
738 
739 /**
740  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
741  * @skb: socket buffer to add attribute to
742  * @attrtype: attribute type
743  * @value: numeric value
744  */
745 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
746 {
747         return nla_put(skb, attrtype, sizeof(u8), &value);
748 }
749 
750 /**
751  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
752  * @skb: socket buffer to add attribute to
753  * @attrtype: attribute type
754  * @value: numeric value
755  */
756 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
757 {
758         return nla_put(skb, attrtype, sizeof(u16), &value);
759 }
760 
761 /**
762  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
763  * @skb: socket buffer to add attribute to
764  * @attrtype: attribute type
765  * @value: numeric value
766  */
767 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
768 {
769         return nla_put(skb, attrtype, sizeof(__be16), &value);
770 }
771 
772 /**
773  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
774  * @skb: socket buffer to add attribute to
775  * @attrtype: attribute type
776  * @value: numeric value
777  */
778 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
779 {
780         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
781 }
782 
783 /**
784  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
785  * @skb: socket buffer to add attribute to
786  * @attrtype: attribute type
787  * @value: numeric value
788  */
789 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
790 {
791         return nla_put(skb, attrtype, sizeof(__le16), &value);
792 }
793 
794 /**
795  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
796  * @skb: socket buffer to add attribute to
797  * @attrtype: attribute type
798  * @value: numeric value
799  */
800 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
801 {
802         return nla_put(skb, attrtype, sizeof(u32), &value);
803 }
804 
805 /**
806  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
807  * @skb: socket buffer to add attribute to
808  * @attrtype: attribute type
809  * @value: numeric value
810  */
811 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
812 {
813         return nla_put(skb, attrtype, sizeof(__be32), &value);
814 }
815 
816 /**
817  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
818  * @skb: socket buffer to add attribute to
819  * @attrtype: attribute type
820  * @value: numeric value
821  */
822 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
823 {
824         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
825 }
826 
827 /**
828  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
829  * @skb: socket buffer to add attribute to
830  * @attrtype: attribute type
831  * @value: numeric value
832  */
833 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
834 {
835         return nla_put(skb, attrtype, sizeof(__le32), &value);
836 }
837 
838 /**
839  * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
840  * @skb: socket buffer to add attribute to
841  * @attrtype: attribute type
842  * @value: numeric value
843  */
844 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
845 {
846         return nla_put(skb, attrtype, sizeof(u64), &value);
847 }
848 
849 /**
850  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer
851  * @skb: socket buffer to add attribute to
852  * @attrtype: attribute type
853  * @value: numeric value
854  */
855 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value)
856 {
857         return nla_put(skb, attrtype, sizeof(__be64), &value);
858 }
859 
860 /**
861  * nla_put_net64 - Add 64-bit network byte order netlink attribute to a socket buffer
862  * @skb: socket buffer to add attribute to
863  * @attrtype: attribute type
864  * @value: numeric value
865  */
866 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value)
867 {
868         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value);
869 }
870 
871 /**
872  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer
873  * @skb: socket buffer to add attribute to
874  * @attrtype: attribute type
875  * @value: numeric value
876  */
877 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value)
878 {
879         return nla_put(skb, attrtype, sizeof(__le64), &value);
880 }
881 
882 /**
883  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
884  * @skb: socket buffer to add attribute to
885  * @attrtype: attribute type
886  * @value: numeric value
887  */
888 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
889 {
890         return nla_put(skb, attrtype, sizeof(s8), &value);
891 }
892 
893 /**
894  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
895  * @skb: socket buffer to add attribute to
896  * @attrtype: attribute type
897  * @value: numeric value
898  */
899 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
900 {
901         return nla_put(skb, attrtype, sizeof(s16), &value);
902 }
903 
904 /**
905  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
906  * @skb: socket buffer to add attribute to
907  * @attrtype: attribute type
908  * @value: numeric value
909  */
910 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
911 {
912         return nla_put(skb, attrtype, sizeof(s32), &value);
913 }
914 
915 /**
916  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer
917  * @skb: socket buffer to add attribute to
918  * @attrtype: attribute type
919  * @value: numeric value
920  */
921 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value)
922 {
923         return nla_put(skb, attrtype, sizeof(s64), &value);
924 }
925 
926 /**
927  * nla_put_string - Add a string netlink attribute to a socket buffer
928  * @skb: socket buffer to add attribute to
929  * @attrtype: attribute type
930  * @str: NUL terminated string
931  */
932 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
933                                  const char *str)
934 {
935         return nla_put(skb, attrtype, strlen(str) + 1, str);
936 }
937 
938 /**
939  * nla_put_flag - Add a flag netlink attribute to a socket buffer
940  * @skb: socket buffer to add attribute to
941  * @attrtype: attribute type
942  */
943 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
944 {
945         return nla_put(skb, attrtype, 0, NULL);
946 }
947 
948 /**
949  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
950  * @skb: socket buffer to add attribute to
951  * @attrtype: attribute type
952  * @njiffies: number of jiffies to convert to msecs
953  */
954 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
955                                 unsigned long njiffies)
956 {
957         u64 tmp = jiffies_to_msecs(njiffies);
958         return nla_put(skb, attrtype, sizeof(u64), &tmp);
959 }
960 
961 /**
962  * nla_get_u32 - return payload of u32 attribute
963  * @nla: u32 netlink attribute
964  */
965 static inline u32 nla_get_u32(const struct nlattr *nla)
966 {
967         return *(u32 *) nla_data(nla);
968 }
969 
970 /**
971  * nla_get_be32 - return payload of __be32 attribute
972  * @nla: __be32 netlink attribute
973  */
974 static inline __be32 nla_get_be32(const struct nlattr *nla)
975 {
976         return *(__be32 *) nla_data(nla);
977 }
978 
979 /**
980  * nla_get_u16 - return payload of u16 attribute
981  * @nla: u16 netlink attribute
982  */
983 static inline u16 nla_get_u16(const struct nlattr *nla)
984 {
985         return *(u16 *) nla_data(nla);
986 }
987 
988 /**
989  * nla_get_be16 - return payload of __be16 attribute
990  * @nla: __be16 netlink attribute
991  */
992 static inline __be16 nla_get_be16(const struct nlattr *nla)
993 {
994         return *(__be16 *) nla_data(nla);
995 }
996 
997 /**
998  * nla_get_le16 - return payload of __le16 attribute
999  * @nla: __le16 netlink attribute
1000  */
1001 static inline __le16 nla_get_le16(const struct nlattr *nla)
1002 {
1003         return *(__le16 *) nla_data(nla);
1004 }
1005 
1006 /**
1007  * nla_get_u8 - return payload of u8 attribute
1008  * @nla: u8 netlink attribute
1009  */
1010 static inline u8 nla_get_u8(const struct nlattr *nla)
1011 {
1012         return *(u8 *) nla_data(nla);
1013 }
1014 
1015 /**
1016  * nla_get_u64 - return payload of u64 attribute
1017  * @nla: u64 netlink attribute
1018  */
1019 static inline u64 nla_get_u64(const struct nlattr *nla)
1020 {
1021         u64 tmp;
1022 
1023         nla_memcpy(&tmp, nla, sizeof(tmp));
1024 
1025         return tmp;
1026 }
1027 
1028 /**
1029  * nla_get_be64 - return payload of __be64 attribute
1030  * @nla: __be64 netlink attribute
1031  */
1032 static inline __be64 nla_get_be64(const struct nlattr *nla)
1033 {
1034         __be64 tmp;
1035 
1036         nla_memcpy(&tmp, nla, sizeof(tmp));
1037 
1038         return tmp;
1039 }
1040 
1041 /**
1042  * nla_get_s32 - return payload of s32 attribute
1043  * @nla: s32 netlink attribute
1044  */
1045 static inline s32 nla_get_s32(const struct nlattr *nla)
1046 {
1047         return *(s32 *) nla_data(nla);
1048 }
1049 
1050 /**
1051  * nla_get_s16 - return payload of s16 attribute
1052  * @nla: s16 netlink attribute
1053  */
1054 static inline s16 nla_get_s16(const struct nlattr *nla)
1055 {
1056         return *(s16 *) nla_data(nla);
1057 }
1058 
1059 /**
1060  * nla_get_s8 - return payload of s8 attribute
1061  * @nla: s8 netlink attribute
1062  */
1063 static inline s8 nla_get_s8(const struct nlattr *nla)
1064 {
1065         return *(s8 *) nla_data(nla);
1066 }
1067 
1068 /**
1069  * nla_get_s64 - return payload of s64 attribute
1070  * @nla: s64 netlink attribute
1071  */
1072 static inline s64 nla_get_s64(const struct nlattr *nla)
1073 {
1074         s64 tmp;
1075 
1076         nla_memcpy(&tmp, nla, sizeof(tmp));
1077 
1078         return tmp;
1079 }
1080 
1081 /**
1082  * nla_get_flag - return payload of flag attribute
1083  * @nla: flag netlink attribute
1084  */
1085 static inline int nla_get_flag(const struct nlattr *nla)
1086 {
1087         return !!nla;
1088 }
1089 
1090 /**
1091  * nla_get_msecs - return payload of msecs attribute
1092  * @nla: msecs netlink attribute
1093  *
1094  * Returns the number of milliseconds in jiffies.
1095  */
1096 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1097 {
1098         u64 msecs = nla_get_u64(nla);
1099 
1100         return msecs_to_jiffies((unsigned long) msecs);
1101 }
1102 
1103 /**
1104  * nla_nest_start - Start a new level of nested attributes
1105  * @skb: socket buffer to add attributes to
1106  * @attrtype: attribute type of container
1107  *
1108  * Returns the container attribute
1109  */
1110 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1111 {
1112         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1113 
1114         if (nla_put(skb, attrtype, 0, NULL) < 0)
1115                 return NULL;
1116 
1117         return start;
1118 }
1119 
1120 /**
1121  * nla_nest_end - Finalize nesting of attributes
1122  * @skb: socket buffer the attributes are stored in
1123  * @start: container attribute
1124  *
1125  * Corrects the container attribute header to include the all
1126  * appeneded attributes.
1127  *
1128  * Returns the total data length of the skb.
1129  */
1130 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1131 {
1132         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1133         return skb->len;
1134 }
1135 
1136 /**
1137  * nla_nest_cancel - Cancel nesting of attributes
1138  * @skb: socket buffer the message is stored in
1139  * @start: container attribute
1140  *
1141  * Removes the container attribute and including all nested
1142  * attributes. Returns -EMSGSIZE
1143  */
1144 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1145 {
1146         nlmsg_trim(skb, start);
1147 }
1148 
1149 /**
1150  * nla_validate_nested - Validate a stream of nested attributes
1151  * @start: container attribute
1152  * @maxtype: maximum attribute type to be expected
1153  * @policy: validation policy
1154  *
1155  * Validates all attributes in the nested attribute stream against the
1156  * specified policy. Attributes with a type exceeding maxtype will be
1157  * ignored. See documenation of struct nla_policy for more details.
1158  *
1159  * Returns 0 on success or a negative error code.
1160  */
1161 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1162                                       const struct nla_policy *policy)
1163 {
1164         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1165 }
1166 
1167 /**
1168  * nla_for_each_attr - iterate over a stream of attributes
1169  * @pos: loop counter, set to current attribute
1170  * @head: head of attribute stream
1171  * @len: length of attribute stream
1172  * @rem: initialized to len, holds bytes currently remaining in stream
1173  */
1174 #define nla_for_each_attr(pos, head, len, rem) \
1175         for (pos = head, rem = len; \
1176              nla_ok(pos, rem); \
1177              pos = nla_next(pos, &(rem)))
1178 
1179 /**
1180  * nla_for_each_nested - iterate over nested attributes
1181  * @pos: loop counter, set to current attribute
1182  * @nla: attribute containing the nested attributes
1183  * @rem: initialized to len, holds bytes currently remaining in stream
1184  */
1185 #define nla_for_each_nested(pos, nla, rem) \
1186         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1187 
1188 #endif
1189 

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