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

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  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 
314 #define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
315 #define NLA_ENSURE_INT_TYPE(tp)                         \
316         (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 ||   \
317                       tp == NLA_S16 || tp == NLA_U16 || \
318                       tp == NLA_S32 || tp == NLA_U32 || \
319                       tp == NLA_S64 || tp == NLA_U64) + tp)
320 #define NLA_ENSURE_NO_VALIDATION_PTR(tp)                \
321         (__NLA_ENSURE(tp != NLA_BITFIELD32 &&           \
322                       tp != NLA_REJECT &&               \
323                       tp != NLA_NESTED &&               \
324                       tp != NLA_NESTED_ARRAY) + tp)
325 
326 #define NLA_POLICY_RANGE(tp, _min, _max) {              \
327         .type = NLA_ENSURE_INT_TYPE(tp),                \
328         .validation_type = NLA_VALIDATE_RANGE,          \
329         .min = _min,                                    \
330         .max = _max                                     \
331 }
332 
333 #define NLA_POLICY_MIN(tp, _min) {                      \
334         .type = NLA_ENSURE_INT_TYPE(tp),                \
335         .validation_type = NLA_VALIDATE_MIN,            \
336         .min = _min,                                    \
337 }
338 
339 #define NLA_POLICY_MAX(tp, _max) {                      \
340         .type = NLA_ENSURE_INT_TYPE(tp),                \
341         .validation_type = NLA_VALIDATE_MAX,            \
342         .max = _max,                                    \
343 }
344 
345 #define NLA_POLICY_VALIDATE_FN(tp, fn, ...) {           \
346         .type = NLA_ENSURE_NO_VALIDATION_PTR(tp),       \
347         .validation_type = NLA_VALIDATE_FUNCTION,       \
348         .validate = fn,                                 \
349         .len = __VA_ARGS__ + 0,                         \
350 }
351 
352 /**
353  * struct nl_info - netlink source information
354  * @nlh: Netlink message header of original request
355  * @portid: Netlink PORTID of requesting application
356  */
357 struct nl_info {
358         struct nlmsghdr         *nlh;
359         struct net              *nl_net;
360         u32                     portid;
361         bool                    skip_notify;
362 };
363 
364 int netlink_rcv_skb(struct sk_buff *skb,
365                     int (*cb)(struct sk_buff *, struct nlmsghdr *,
366                               struct netlink_ext_ack *));
367 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
368                  unsigned int group, int report, gfp_t flags);
369 
370 int nla_validate(const struct nlattr *head, int len, int maxtype,
371                  const struct nla_policy *policy,
372                  struct netlink_ext_ack *extack);
373 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
374               int len, const struct nla_policy *policy,
375               struct netlink_ext_ack *extack);
376 int nla_parse_strict(struct nlattr **tb, int maxtype, const struct nlattr *head,
377                      int len, const struct nla_policy *policy,
378                      struct netlink_ext_ack *extack);
379 int nla_policy_len(const struct nla_policy *, int);
380 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
381 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
382 char *nla_strdup(const struct nlattr *nla, gfp_t flags);
383 int nla_memcpy(void *dest, const struct nlattr *src, int count);
384 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
385 int nla_strcmp(const struct nlattr *nla, const char *str);
386 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
387 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
388                                    int attrlen, int padattr);
389 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
390 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
391 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
392                                  int attrlen, int padattr);
393 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
394 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
395                const void *data);
396 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
397                      const void *data, int padattr);
398 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
399 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
400 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
401                   const void *data, int padattr);
402 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
403 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
404 
405 /**************************************************************************
406  * Netlink Messages
407  **************************************************************************/
408 
409 /**
410  * nlmsg_msg_size - length of netlink message not including padding
411  * @payload: length of message payload
412  */
413 static inline int nlmsg_msg_size(int payload)
414 {
415         return NLMSG_HDRLEN + payload;
416 }
417 
418 /**
419  * nlmsg_total_size - length of netlink message including padding
420  * @payload: length of message payload
421  */
422 static inline int nlmsg_total_size(int payload)
423 {
424         return NLMSG_ALIGN(nlmsg_msg_size(payload));
425 }
426 
427 /**
428  * nlmsg_padlen - length of padding at the message's tail
429  * @payload: length of message payload
430  */
431 static inline int nlmsg_padlen(int payload)
432 {
433         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
434 }
435 
436 /**
437  * nlmsg_data - head of message payload
438  * @nlh: netlink message header
439  */
440 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
441 {
442         return (unsigned char *) nlh + NLMSG_HDRLEN;
443 }
444 
445 /**
446  * nlmsg_len - length of message payload
447  * @nlh: netlink message header
448  */
449 static inline int nlmsg_len(const struct nlmsghdr *nlh)
450 {
451         return nlh->nlmsg_len - NLMSG_HDRLEN;
452 }
453 
454 /**
455  * nlmsg_attrdata - head of attributes data
456  * @nlh: netlink message header
457  * @hdrlen: length of family specific header
458  */
459 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
460                                             int hdrlen)
461 {
462         unsigned char *data = nlmsg_data(nlh);
463         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
464 }
465 
466 /**
467  * nlmsg_attrlen - length of attributes data
468  * @nlh: netlink message header
469  * @hdrlen: length of family specific header
470  */
471 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
472 {
473         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
474 }
475 
476 /**
477  * nlmsg_ok - check if the netlink message fits into the remaining bytes
478  * @nlh: netlink message header
479  * @remaining: number of bytes remaining in message stream
480  */
481 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
482 {
483         return (remaining >= (int) sizeof(struct nlmsghdr) &&
484                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
485                 nlh->nlmsg_len <= remaining);
486 }
487 
488 /**
489  * nlmsg_next - next netlink message in message stream
490  * @nlh: netlink message header
491  * @remaining: number of bytes remaining in message stream
492  *
493  * Returns the next netlink message in the message stream and
494  * decrements remaining by the size of the current message.
495  */
496 static inline struct nlmsghdr *
497 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
498 {
499         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
500 
501         *remaining -= totlen;
502 
503         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
504 }
505 
506 /**
507  * nlmsg_parse - parse attributes of a netlink message
508  * @nlh: netlink message header
509  * @hdrlen: length of family specific header
510  * @tb: destination array with maxtype+1 elements
511  * @maxtype: maximum attribute type to be expected
512  * @policy: validation policy
513  * @extack: extended ACK report struct
514  *
515  * See nla_parse()
516  */
517 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
518                               struct nlattr *tb[], int maxtype,
519                               const struct nla_policy *policy,
520                               struct netlink_ext_ack *extack)
521 {
522         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
523                 NL_SET_ERR_MSG(extack, "Invalid header length");
524                 return -EINVAL;
525         }
526 
527         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
528                          nlmsg_attrlen(nlh, hdrlen), policy, extack);
529 }
530 
531 static inline int nlmsg_parse_strict(const struct nlmsghdr *nlh, int hdrlen,
532                                      struct nlattr *tb[], int maxtype,
533                                      const struct nla_policy *policy,
534                                      struct netlink_ext_ack *extack)
535 {
536         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
537                 NL_SET_ERR_MSG(extack, "Invalid header length");
538                 return -EINVAL;
539         }
540 
541         return nla_parse_strict(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
542                                 nlmsg_attrlen(nlh, hdrlen), policy, extack);
543 }
544 
545 /**
546  * nlmsg_find_attr - find a specific attribute in a netlink message
547  * @nlh: netlink message header
548  * @hdrlen: length of familiy specific header
549  * @attrtype: type of attribute to look for
550  *
551  * Returns the first attribute which matches the specified type.
552  */
553 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
554                                              int hdrlen, int attrtype)
555 {
556         return nla_find(nlmsg_attrdata(nlh, hdrlen),
557                         nlmsg_attrlen(nlh, hdrlen), attrtype);
558 }
559 
560 /**
561  * nlmsg_validate - validate a netlink message including attributes
562  * @nlh: netlinket message header
563  * @hdrlen: length of familiy specific header
564  * @maxtype: maximum attribute type to be expected
565  * @policy: validation policy
566  * @extack: extended ACK report struct
567  */
568 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
569                                  int hdrlen, int maxtype,
570                                  const struct nla_policy *policy,
571                                  struct netlink_ext_ack *extack)
572 {
573         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
574                 return -EINVAL;
575 
576         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
577                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy,
578                             extack);
579 }
580 
581 /**
582  * nlmsg_report - need to report back to application?
583  * @nlh: netlink message header
584  *
585  * Returns 1 if a report back to the application is requested.
586  */
587 static inline int nlmsg_report(const struct nlmsghdr *nlh)
588 {
589         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
590 }
591 
592 /**
593  * nlmsg_for_each_attr - iterate over a stream of attributes
594  * @pos: loop counter, set to current attribute
595  * @nlh: netlink message header
596  * @hdrlen: length of familiy specific header
597  * @rem: initialized to len, holds bytes currently remaining in stream
598  */
599 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
600         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
601                           nlmsg_attrlen(nlh, hdrlen), rem)
602 
603 /**
604  * nlmsg_put - Add a new netlink message to an skb
605  * @skb: socket buffer to store message in
606  * @portid: netlink PORTID of requesting application
607  * @seq: sequence number of message
608  * @type: message type
609  * @payload: length of message payload
610  * @flags: message flags
611  *
612  * Returns NULL if the tailroom of the skb is insufficient to store
613  * the message header and payload.
614  */
615 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
616                                          int type, int payload, int flags)
617 {
618         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
619                 return NULL;
620 
621         return __nlmsg_put(skb, portid, seq, type, payload, flags);
622 }
623 
624 /**
625  * nlmsg_put_answer - Add a new callback based netlink message to an skb
626  * @skb: socket buffer to store message in
627  * @cb: netlink callback
628  * @type: message type
629  * @payload: length of message payload
630  * @flags: message flags
631  *
632  * Returns NULL if the tailroom of the skb is insufficient to store
633  * the message header and payload.
634  */
635 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
636                                                 struct netlink_callback *cb,
637                                                 int type, int payload,
638                                                 int flags)
639 {
640         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
641                          type, payload, flags);
642 }
643 
644 /**
645  * nlmsg_new - Allocate a new netlink message
646  * @payload: size of the message payload
647  * @flags: the type of memory to allocate.
648  *
649  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
650  * and a good default is needed.
651  */
652 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
653 {
654         return alloc_skb(nlmsg_total_size(payload), flags);
655 }
656 
657 /**
658  * nlmsg_end - Finalize a netlink message
659  * @skb: socket buffer the message is stored in
660  * @nlh: netlink message header
661  *
662  * Corrects the netlink message header to include the appeneded
663  * attributes. Only necessary if attributes have been added to
664  * the message.
665  */
666 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
667 {
668         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
669 }
670 
671 /**
672  * nlmsg_get_pos - return current position in netlink message
673  * @skb: socket buffer the message is stored in
674  *
675  * Returns a pointer to the current tail of the message.
676  */
677 static inline void *nlmsg_get_pos(struct sk_buff *skb)
678 {
679         return skb_tail_pointer(skb);
680 }
681 
682 /**
683  * nlmsg_trim - Trim message to a mark
684  * @skb: socket buffer the message is stored in
685  * @mark: mark to trim to
686  *
687  * Trims the message to the provided mark.
688  */
689 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
690 {
691         if (mark) {
692                 WARN_ON((unsigned char *) mark < skb->data);
693                 skb_trim(skb, (unsigned char *) mark - skb->data);
694         }
695 }
696 
697 /**
698  * nlmsg_cancel - Cancel construction of a netlink message
699  * @skb: socket buffer the message is stored in
700  * @nlh: netlink message header
701  *
702  * Removes the complete netlink message including all
703  * attributes from the socket buffer again.
704  */
705 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
706 {
707         nlmsg_trim(skb, nlh);
708 }
709 
710 /**
711  * nlmsg_free - free a netlink message
712  * @skb: socket buffer of netlink message
713  */
714 static inline void nlmsg_free(struct sk_buff *skb)
715 {
716         kfree_skb(skb);
717 }
718 
719 /**
720  * nlmsg_multicast - multicast a netlink message
721  * @sk: netlink socket to spread messages to
722  * @skb: netlink message as socket buffer
723  * @portid: own netlink portid to avoid sending to yourself
724  * @group: multicast group id
725  * @flags: allocation flags
726  */
727 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
728                                   u32 portid, unsigned int group, gfp_t flags)
729 {
730         int err;
731 
732         NETLINK_CB(skb).dst_group = group;
733 
734         err = netlink_broadcast(sk, skb, portid, group, flags);
735         if (err > 0)
736                 err = 0;
737 
738         return err;
739 }
740 
741 /**
742  * nlmsg_unicast - unicast a netlink message
743  * @sk: netlink socket to spread message to
744  * @skb: netlink message as socket buffer
745  * @portid: netlink portid of the destination socket
746  */
747 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
748 {
749         int err;
750 
751         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
752         if (err > 0)
753                 err = 0;
754 
755         return err;
756 }
757 
758 /**
759  * nlmsg_for_each_msg - iterate over a stream of messages
760  * @pos: loop counter, set to current message
761  * @head: head of message stream
762  * @len: length of message stream
763  * @rem: initialized to len, holds bytes currently remaining in stream
764  */
765 #define nlmsg_for_each_msg(pos, head, len, rem) \
766         for (pos = head, rem = len; \
767              nlmsg_ok(pos, rem); \
768              pos = nlmsg_next(pos, &(rem)))
769 
770 /**
771  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
772  * @cb: netlink callback structure that stores the sequence number
773  * @nlh: netlink message header to write the flag to
774  *
775  * This function checks if the sequence (generation) number changed during dump
776  * and if it did, advertises it in the netlink message header.
777  *
778  * The correct way to use it is to set cb->seq to the generation counter when
779  * all locks for dumping have been acquired, and then call this function for
780  * each message that is generated.
781  *
782  * Note that due to initialisation concerns, 0 is an invalid sequence number
783  * and must not be used by code that uses this functionality.
784  */
785 static inline void
786 nl_dump_check_consistent(struct netlink_callback *cb,
787                          struct nlmsghdr *nlh)
788 {
789         if (cb->prev_seq && cb->seq != cb->prev_seq)
790                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
791         cb->prev_seq = cb->seq;
792 }
793 
794 /**************************************************************************
795  * Netlink Attributes
796  **************************************************************************/
797 
798 /**
799  * nla_attr_size - length of attribute not including padding
800  * @payload: length of payload
801  */
802 static inline int nla_attr_size(int payload)
803 {
804         return NLA_HDRLEN + payload;
805 }
806 
807 /**
808  * nla_total_size - total length of attribute including padding
809  * @payload: length of payload
810  */
811 static inline int nla_total_size(int payload)
812 {
813         return NLA_ALIGN(nla_attr_size(payload));
814 }
815 
816 /**
817  * nla_padlen - length of padding at the tail of attribute
818  * @payload: length of payload
819  */
820 static inline int nla_padlen(int payload)
821 {
822         return nla_total_size(payload) - nla_attr_size(payload);
823 }
824 
825 /**
826  * nla_type - attribute type
827  * @nla: netlink attribute
828  */
829 static inline int nla_type(const struct nlattr *nla)
830 {
831         return nla->nla_type & NLA_TYPE_MASK;
832 }
833 
834 /**
835  * nla_data - head of payload
836  * @nla: netlink attribute
837  */
838 static inline void *nla_data(const struct nlattr *nla)
839 {
840         return (char *) nla + NLA_HDRLEN;
841 }
842 
843 /**
844  * nla_len - length of payload
845  * @nla: netlink attribute
846  */
847 static inline int nla_len(const struct nlattr *nla)
848 {
849         return nla->nla_len - NLA_HDRLEN;
850 }
851 
852 /**
853  * nla_ok - check if the netlink attribute fits into the remaining bytes
854  * @nla: netlink attribute
855  * @remaining: number of bytes remaining in attribute stream
856  */
857 static inline int nla_ok(const struct nlattr *nla, int remaining)
858 {
859         return remaining >= (int) sizeof(*nla) &&
860                nla->nla_len >= sizeof(*nla) &&
861                nla->nla_len <= remaining;
862 }
863 
864 /**
865  * nla_next - next netlink attribute in attribute stream
866  * @nla: netlink attribute
867  * @remaining: number of bytes remaining in attribute stream
868  *
869  * Returns the next netlink attribute in the attribute stream and
870  * decrements remaining by the size of the current attribute.
871  */
872 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
873 {
874         unsigned int totlen = NLA_ALIGN(nla->nla_len);
875 
876         *remaining -= totlen;
877         return (struct nlattr *) ((char *) nla + totlen);
878 }
879 
880 /**
881  * nla_find_nested - find attribute in a set of nested attributes
882  * @nla: attribute containing the nested attributes
883  * @attrtype: type of attribute to look for
884  *
885  * Returns the first attribute which matches the specified type.
886  */
887 static inline struct nlattr *
888 nla_find_nested(const struct nlattr *nla, int attrtype)
889 {
890         return nla_find(nla_data(nla), nla_len(nla), attrtype);
891 }
892 
893 /**
894  * nla_parse_nested - parse nested attributes
895  * @tb: destination array with maxtype+1 elements
896  * @maxtype: maximum attribute type to be expected
897  * @nla: attribute containing the nested attributes
898  * @policy: validation policy
899  * @extack: extended ACK report struct
900  *
901  * See nla_parse()
902  */
903 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
904                                    const struct nlattr *nla,
905                                    const struct nla_policy *policy,
906                                    struct netlink_ext_ack *extack)
907 {
908         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
909                          extack);
910 }
911 
912 /**
913  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
914  * @skb: socket buffer to add attribute to
915  * @attrtype: attribute type
916  * @value: numeric value
917  */
918 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
919 {
920         /* temporary variables to work around GCC PR81715 with asan-stack=1 */
921         u8 tmp = value;
922 
923         return nla_put(skb, attrtype, sizeof(u8), &tmp);
924 }
925 
926 /**
927  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
928  * @skb: socket buffer to add attribute to
929  * @attrtype: attribute type
930  * @value: numeric value
931  */
932 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
933 {
934         u16 tmp = value;
935 
936         return nla_put(skb, attrtype, sizeof(u16), &tmp);
937 }
938 
939 /**
940  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
941  * @skb: socket buffer to add attribute to
942  * @attrtype: attribute type
943  * @value: numeric value
944  */
945 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
946 {
947         __be16 tmp = value;
948 
949         return nla_put(skb, attrtype, sizeof(__be16), &tmp);
950 }
951 
952 /**
953  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
954  * @skb: socket buffer to add attribute to
955  * @attrtype: attribute type
956  * @value: numeric value
957  */
958 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
959 {
960         __be16 tmp = value;
961 
962         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
963 }
964 
965 /**
966  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
967  * @skb: socket buffer to add attribute to
968  * @attrtype: attribute type
969  * @value: numeric value
970  */
971 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
972 {
973         __le16 tmp = value;
974 
975         return nla_put(skb, attrtype, sizeof(__le16), &tmp);
976 }
977 
978 /**
979  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
980  * @skb: socket buffer to add attribute to
981  * @attrtype: attribute type
982  * @value: numeric value
983  */
984 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
985 {
986         u32 tmp = value;
987 
988         return nla_put(skb, attrtype, sizeof(u32), &tmp);
989 }
990 
991 /**
992  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
993  * @skb: socket buffer to add attribute to
994  * @attrtype: attribute type
995  * @value: numeric value
996  */
997 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
998 {
999         __be32 tmp = value;
1000 
1001         return nla_put(skb, attrtype, sizeof(__be32), &tmp);
1002 }
1003 
1004 /**
1005  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
1006  * @skb: socket buffer to add attribute to
1007  * @attrtype: attribute type
1008  * @value: numeric value
1009  */
1010 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
1011 {
1012         __be32 tmp = value;
1013 
1014         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
1015 }
1016 
1017 /**
1018  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
1019  * @skb: socket buffer to add attribute to
1020  * @attrtype: attribute type
1021  * @value: numeric value
1022  */
1023 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
1024 {
1025         __le32 tmp = value;
1026 
1027         return nla_put(skb, attrtype, sizeof(__le32), &tmp);
1028 }
1029 
1030 /**
1031  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
1032  * @skb: socket buffer to add attribute to
1033  * @attrtype: attribute type
1034  * @value: numeric value
1035  * @padattr: attribute type for the padding
1036  */
1037 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
1038                                     u64 value, int padattr)
1039 {
1040         u64 tmp = value;
1041 
1042         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1043 }
1044 
1045 /**
1046  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
1047  * @skb: socket buffer to add attribute to
1048  * @attrtype: attribute type
1049  * @value: numeric value
1050  * @padattr: attribute type for the padding
1051  */
1052 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
1053                                int padattr)
1054 {
1055         __be64 tmp = value;
1056 
1057         return nla_put_64bit(skb, attrtype, sizeof(__be64), &tmp, padattr);
1058 }
1059 
1060 /**
1061  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
1062  * @skb: socket buffer to add attribute to
1063  * @attrtype: attribute type
1064  * @value: numeric value
1065  * @padattr: attribute type for the padding
1066  */
1067 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
1068                                 int padattr)
1069 {
1070         __be64 tmp = value;
1071 
1072         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, tmp,
1073                             padattr);
1074 }
1075 
1076 /**
1077  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
1078  * @skb: socket buffer to add attribute to
1079  * @attrtype: attribute type
1080  * @value: numeric value
1081  * @padattr: attribute type for the padding
1082  */
1083 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
1084                                int padattr)
1085 {
1086         __le64 tmp = value;
1087 
1088         return nla_put_64bit(skb, attrtype, sizeof(__le64), &tmp, padattr);
1089 }
1090 
1091 /**
1092  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
1093  * @skb: socket buffer to add attribute to
1094  * @attrtype: attribute type
1095  * @value: numeric value
1096  */
1097 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
1098 {
1099         s8 tmp = value;
1100 
1101         return nla_put(skb, attrtype, sizeof(s8), &tmp);
1102 }
1103 
1104 /**
1105  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
1106  * @skb: socket buffer to add attribute to
1107  * @attrtype: attribute type
1108  * @value: numeric value
1109  */
1110 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
1111 {
1112         s16 tmp = value;
1113 
1114         return nla_put(skb, attrtype, sizeof(s16), &tmp);
1115 }
1116 
1117 /**
1118  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
1119  * @skb: socket buffer to add attribute to
1120  * @attrtype: attribute type
1121  * @value: numeric value
1122  */
1123 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
1124 {
1125         s32 tmp = value;
1126 
1127         return nla_put(skb, attrtype, sizeof(s32), &tmp);
1128 }
1129 
1130 /**
1131  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
1132  * @skb: socket buffer to add attribute to
1133  * @attrtype: attribute type
1134  * @value: numeric value
1135  * @padattr: attribute type for the padding
1136  */
1137 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
1138                               int padattr)
1139 {
1140         s64 tmp = value;
1141 
1142         return nla_put_64bit(skb, attrtype, sizeof(s64), &tmp, padattr);
1143 }
1144 
1145 /**
1146  * nla_put_string - Add a string netlink attribute to a socket buffer
1147  * @skb: socket buffer to add attribute to
1148  * @attrtype: attribute type
1149  * @str: NUL terminated string
1150  */
1151 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
1152                                  const char *str)
1153 {
1154         return nla_put(skb, attrtype, strlen(str) + 1, str);
1155 }
1156 
1157 /**
1158  * nla_put_flag - Add a flag netlink attribute to a socket buffer
1159  * @skb: socket buffer to add attribute to
1160  * @attrtype: attribute type
1161  */
1162 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
1163 {
1164         return nla_put(skb, attrtype, 0, NULL);
1165 }
1166 
1167 /**
1168  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
1169  * @skb: socket buffer to add attribute to
1170  * @attrtype: attribute type
1171  * @njiffies: number of jiffies to convert to msecs
1172  * @padattr: attribute type for the padding
1173  */
1174 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
1175                                 unsigned long njiffies, int padattr)
1176 {
1177         u64 tmp = jiffies_to_msecs(njiffies);
1178 
1179         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
1180 }
1181 
1182 /**
1183  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1184  * buffer
1185  * @skb: socket buffer to add attribute to
1186  * @attrtype: attribute type
1187  * @addr: IPv4 address
1188  */
1189 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1190                                   __be32 addr)
1191 {
1192         __be32 tmp = addr;
1193 
1194         return nla_put_be32(skb, attrtype, tmp);
1195 }
1196 
1197 /**
1198  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1199  * buffer
1200  * @skb: socket buffer to add attribute to
1201  * @attrtype: attribute type
1202  * @addr: IPv6 address
1203  */
1204 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1205                                    const struct in6_addr *addr)
1206 {
1207         return nla_put(skb, attrtype, sizeof(*addr), addr);
1208 }
1209 
1210 /**
1211  * nla_get_u32 - return payload of u32 attribute
1212  * @nla: u32 netlink attribute
1213  */
1214 static inline u32 nla_get_u32(const struct nlattr *nla)
1215 {
1216         return *(u32 *) nla_data(nla);
1217 }
1218 
1219 /**
1220  * nla_get_be32 - return payload of __be32 attribute
1221  * @nla: __be32 netlink attribute
1222  */
1223 static inline __be32 nla_get_be32(const struct nlattr *nla)
1224 {
1225         return *(__be32 *) nla_data(nla);
1226 }
1227 
1228 /**
1229  * nla_get_le32 - return payload of __le32 attribute
1230  * @nla: __le32 netlink attribute
1231  */
1232 static inline __le32 nla_get_le32(const struct nlattr *nla)
1233 {
1234         return *(__le32 *) nla_data(nla);
1235 }
1236 
1237 /**
1238  * nla_get_u16 - return payload of u16 attribute
1239  * @nla: u16 netlink attribute
1240  */
1241 static inline u16 nla_get_u16(const struct nlattr *nla)
1242 {
1243         return *(u16 *) nla_data(nla);
1244 }
1245 
1246 /**
1247  * nla_get_be16 - return payload of __be16 attribute
1248  * @nla: __be16 netlink attribute
1249  */
1250 static inline __be16 nla_get_be16(const struct nlattr *nla)
1251 {
1252         return *(__be16 *) nla_data(nla);
1253 }
1254 
1255 /**
1256  * nla_get_le16 - return payload of __le16 attribute
1257  * @nla: __le16 netlink attribute
1258  */
1259 static inline __le16 nla_get_le16(const struct nlattr *nla)
1260 {
1261         return *(__le16 *) nla_data(nla);
1262 }
1263 
1264 /**
1265  * nla_get_u8 - return payload of u8 attribute
1266  * @nla: u8 netlink attribute
1267  */
1268 static inline u8 nla_get_u8(const struct nlattr *nla)
1269 {
1270         return *(u8 *) nla_data(nla);
1271 }
1272 
1273 /**
1274  * nla_get_u64 - return payload of u64 attribute
1275  * @nla: u64 netlink attribute
1276  */
1277 static inline u64 nla_get_u64(const struct nlattr *nla)
1278 {
1279         u64 tmp;
1280 
1281         nla_memcpy(&tmp, nla, sizeof(tmp));
1282 
1283         return tmp;
1284 }
1285 
1286 /**
1287  * nla_get_be64 - return payload of __be64 attribute
1288  * @nla: __be64 netlink attribute
1289  */
1290 static inline __be64 nla_get_be64(const struct nlattr *nla)
1291 {
1292         __be64 tmp;
1293 
1294         nla_memcpy(&tmp, nla, sizeof(tmp));
1295 
1296         return tmp;
1297 }
1298 
1299 /**
1300  * nla_get_le64 - return payload of __le64 attribute
1301  * @nla: __le64 netlink attribute
1302  */
1303 static inline __le64 nla_get_le64(const struct nlattr *nla)
1304 {
1305         return *(__le64 *) nla_data(nla);
1306 }
1307 
1308 /**
1309  * nla_get_s32 - return payload of s32 attribute
1310  * @nla: s32 netlink attribute
1311  */
1312 static inline s32 nla_get_s32(const struct nlattr *nla)
1313 {
1314         return *(s32 *) nla_data(nla);
1315 }
1316 
1317 /**
1318  * nla_get_s16 - return payload of s16 attribute
1319  * @nla: s16 netlink attribute
1320  */
1321 static inline s16 nla_get_s16(const struct nlattr *nla)
1322 {
1323         return *(s16 *) nla_data(nla);
1324 }
1325 
1326 /**
1327  * nla_get_s8 - return payload of s8 attribute
1328  * @nla: s8 netlink attribute
1329  */
1330 static inline s8 nla_get_s8(const struct nlattr *nla)
1331 {
1332         return *(s8 *) nla_data(nla);
1333 }
1334 
1335 /**
1336  * nla_get_s64 - return payload of s64 attribute
1337  * @nla: s64 netlink attribute
1338  */
1339 static inline s64 nla_get_s64(const struct nlattr *nla)
1340 {
1341         s64 tmp;
1342 
1343         nla_memcpy(&tmp, nla, sizeof(tmp));
1344 
1345         return tmp;
1346 }
1347 
1348 /**
1349  * nla_get_flag - return payload of flag attribute
1350  * @nla: flag netlink attribute
1351  */
1352 static inline int nla_get_flag(const struct nlattr *nla)
1353 {
1354         return !!nla;
1355 }
1356 
1357 /**
1358  * nla_get_msecs - return payload of msecs attribute
1359  * @nla: msecs netlink attribute
1360  *
1361  * Returns the number of milliseconds in jiffies.
1362  */
1363 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1364 {
1365         u64 msecs = nla_get_u64(nla);
1366 
1367         return msecs_to_jiffies((unsigned long) msecs);
1368 }
1369 
1370 /**
1371  * nla_get_in_addr - return payload of IPv4 address attribute
1372  * @nla: IPv4 address netlink attribute
1373  */
1374 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1375 {
1376         return *(__be32 *) nla_data(nla);
1377 }
1378 
1379 /**
1380  * nla_get_in6_addr - return payload of IPv6 address attribute
1381  * @nla: IPv6 address netlink attribute
1382  */
1383 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1384 {
1385         struct in6_addr tmp;
1386 
1387         nla_memcpy(&tmp, nla, sizeof(tmp));
1388         return tmp;
1389 }
1390 
1391 /**
1392  * nla_get_bitfield32 - return payload of 32 bitfield attribute
1393  * @nla: nla_bitfield32 attribute
1394  */
1395 static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
1396 {
1397         struct nla_bitfield32 tmp;
1398 
1399         nla_memcpy(&tmp, nla, sizeof(tmp));
1400         return tmp;
1401 }
1402 
1403 /**
1404  * nla_memdup - duplicate attribute memory (kmemdup)
1405  * @src: netlink attribute to duplicate from
1406  * @gfp: GFP mask
1407  */
1408 static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
1409 {
1410         return kmemdup(nla_data(src), nla_len(src), gfp);
1411 }
1412 
1413 /**
1414  * nla_nest_start - Start a new level of nested attributes
1415  * @skb: socket buffer to add attributes to
1416  * @attrtype: attribute type of container
1417  *
1418  * Returns the container attribute
1419  */
1420 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1421 {
1422         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1423 
1424         if (nla_put(skb, attrtype, 0, NULL) < 0)
1425                 return NULL;
1426 
1427         return start;
1428 }
1429 
1430 /**
1431  * nla_nest_end - Finalize nesting of attributes
1432  * @skb: socket buffer the attributes are stored in
1433  * @start: container attribute
1434  *
1435  * Corrects the container attribute header to include the all
1436  * appeneded attributes.
1437  *
1438  * Returns the total data length of the skb.
1439  */
1440 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1441 {
1442         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1443         return skb->len;
1444 }
1445 
1446 /**
1447  * nla_nest_cancel - Cancel nesting of attributes
1448  * @skb: socket buffer the message is stored in
1449  * @start: container attribute
1450  *
1451  * Removes the container attribute and including all nested
1452  * attributes. Returns -EMSGSIZE
1453  */
1454 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1455 {
1456         nlmsg_trim(skb, start);
1457 }
1458 
1459 /**
1460  * nla_validate_nested - Validate a stream of nested attributes
1461  * @start: container attribute
1462  * @maxtype: maximum attribute type to be expected
1463  * @policy: validation policy
1464  * @extack: extended ACK report struct
1465  *
1466  * Validates all attributes in the nested attribute stream against the
1467  * specified policy. Attributes with a type exceeding maxtype will be
1468  * ignored. See documenation of struct nla_policy for more details.
1469  *
1470  * Returns 0 on success or a negative error code.
1471  */
1472 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1473                                       const struct nla_policy *policy,
1474                                       struct netlink_ext_ack *extack)
1475 {
1476         return nla_validate(nla_data(start), nla_len(start), maxtype, policy,
1477                             extack);
1478 }
1479 
1480 /**
1481  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1482  * @skb: socket buffer the message is stored in
1483  *
1484  * Return true if padding is needed to align the next attribute (nla_data()) to
1485  * a 64-bit aligned area.
1486  */
1487 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1488 {
1489 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1490         /* The nlattr header is 4 bytes in size, that's why we test
1491          * if the skb->data _is_ aligned.  A NOP attribute, plus
1492          * nlattr header for next attribute, will make nla_data()
1493          * 8-byte aligned.
1494          */
1495         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1496                 return true;
1497 #endif
1498         return false;
1499 }
1500 
1501 /**
1502  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1503  * @skb: socket buffer the message is stored in
1504  * @padattr: attribute type for the padding
1505  *
1506  * Conditionally emit a padding netlink attribute in order to make
1507  * the next attribute we emit have a 64-bit aligned nla_data() area.
1508  * This will only be done in architectures which do not have
1509  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1510  *
1511  * Returns zero on success or a negative error code.
1512  */
1513 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1514 {
1515         if (nla_need_padding_for_64bit(skb) &&
1516             !nla_reserve(skb, padattr, 0))
1517                 return -EMSGSIZE;
1518 
1519         return 0;
1520 }
1521 
1522 /**
1523  * nla_total_size_64bit - total length of attribute including padding
1524  * @payload: length of payload
1525  */
1526 static inline int nla_total_size_64bit(int payload)
1527 {
1528         return NLA_ALIGN(nla_attr_size(payload))
1529 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1530                 + NLA_ALIGN(nla_attr_size(0))
1531 #endif
1532                 ;
1533 }
1534 
1535 /**
1536  * nla_for_each_attr - iterate over a stream of attributes
1537  * @pos: loop counter, set to current attribute
1538  * @head: head of attribute stream
1539  * @len: length of attribute stream
1540  * @rem: initialized to len, holds bytes currently remaining in stream
1541  */
1542 #define nla_for_each_attr(pos, head, len, rem) \
1543         for (pos = head, rem = len; \
1544              nla_ok(pos, rem); \
1545              pos = nla_next(pos, &(rem)))
1546 
1547 /**
1548  * nla_for_each_nested - iterate over nested attributes
1549  * @pos: loop counter, set to current attribute
1550  * @nla: attribute containing the nested attributes
1551  * @rem: initialized to len, holds bytes currently remaining in stream
1552  */
1553 #define nla_for_each_nested(pos, nla, rem) \
1554         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1555 
1556 /**
1557  * nla_is_last - Test if attribute is last in stream
1558  * @nla: attribute to test
1559  * @rem: bytes remaining in stream
1560  */
1561 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1562 {
1563         return nla->nla_len == rem;
1564 }
1565 
1566 #endif
1567 

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