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

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Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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