include/net/netlink.h

   1 #ifndef __NET_NETLINK_H
   2 #define __NET_NETLINK_H
   3
   4 #include <linux/types.h>
   5 #include <linux/netlink.h>
   6 #include <linux/jiffies.h>
   7 #include <linux/in6.h>
   8
   9 /* ========================================================================
  10  *         Netlink Messages and Attributes Interface (As Seen On TV)
  11  * ------------------------------------------------------------------------
  12  *                          Messages Interface
  13  * ------------------------------------------------------------------------
  14  *
  15  * Message Format:
  16  *    <--- nlmsg_total_size(payload)  --->
  17  *    <-- nlmsg_msg_size(payload) ->
  18  *   +----------+- - -+-------------+- - -+-------- - -
  19  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  20  *   +----------+- - -+-------------+- - -+-------- - -
  21  *   nlmsg_data(nlh)---^                   ^
  22  *   nlmsg_next(nlh)-----------------------+
  23  *
  24  * Payload Format:
  25  *    <---------------------- nlmsg_len(nlh) --------------------->
  26  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  27  *   +----------------------+- - -+--------------------------------+
  28  *   |     Family Header    | Pad |           Attributes           |
  29  *   +----------------------+- - -+--------------------------------+
  30  *   nlmsg_attrdata(nlh, hdrlen)---^
  31  *
  32  * Data Structures:
  33  *   struct nlmsghdr                    netlink message header
  34  *
  35  * Message Construction:
  36  *   nlmsg_new()                        create a new netlink message
  37  *   nlmsg_put()                        add a netlink message to an skb
  38  *   nlmsg_put_answer()                 callback based nlmsg_put()
  39  *   nlmsg_end()                        finalize netlink message
  40  *   nlmsg_get_pos()                    return current position in message
  41  *   nlmsg_trim()                       trim part of message
  42  *   nlmsg_cancel()                     cancel message construction
  43  *   nlmsg_free()                       free a netlink message
  44  *
  45  * Message Sending:
  46  *   nlmsg_multicast()                  multicast message to several groups
  47  *   nlmsg_unicast()                    unicast a message to a single socket
  48  *   nlmsg_notify()                     send notification message
  49  *
  50  * Message Length Calculations:
  51  *   nlmsg_msg_size(payload)            length of message w/o padding
  52  *   nlmsg_total_size(payload)          length of message w/ padding
  53  *   nlmsg_padlen(payload)              length of padding at tail
  54  *
  55  * Message Payload Access:
  56  *   nlmsg_data(nlh)                    head of message payload
  57  *   nlmsg_len(nlh)                     length of message payload
  58  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  59  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  60  *
  61  * Message Parsing:
  62  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  63  *   nlmsg_next(nlh, remaining)         get next netlink message
  64  *   nlmsg_parse()                      parse attributes of a message
  65  *   nlmsg_find_attr()                  find an attribute in a message
  66  *   nlmsg_for_each_msg()               loop over all messages
  67  *   nlmsg_validate()                   validate netlink message incl. attrs
  68  *   nlmsg_for_each_attr()              loop over all attributes
  69  *
  70  * Misc:
  71  *   nlmsg_report()                     report back to application?
  72  *
  73  * ------------------------------------------------------------------------
  74  *                          Attributes Interface
  75  * ------------------------------------------------------------------------
  76  *
  77  * Attribute Format:
  78  *    <------- nla_total_size(payload) ------->
  79  *    <---- nla_attr_size(payload) ----->
  80  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  81  *   |  Header  | Pad |     Payload      | Pad |  Header
  82  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  83  *                     <- nla_len(nla) ->      ^
  84  *   nla_data(nla)----^                        |
  85  *   nla_next(nla)-----------------------------'
  86  *
  87  * Data Structures:
  88  *   struct nlattr                      netlink attribute header
  89  *
  90  * Attribute Construction:
  91  *   nla_reserve(skb, type, len)        reserve room for an attribute
  92  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  93  *   nla_put(skb, type, len, data)      add attribute to skb
  94  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  95  *   nla_append(skb, len, data)         append data to skb
  96  *
  97  * Attribute Construction for Basic Types:
  98  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  99  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
 100  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
 101  *   nla_put_u64_64bits(skb, type,
 102  *                      value, padattr) add u64 attribute to skb
 103  *   nla_put_s8(skb, type, value)       add s8 attribute to skb
 104  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
 105  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
 106  *   nla_put_s64(skb, type, value,
 107  *               padattr)               add s64 attribute to skb
 108  *   nla_put_string(skb, type, str)     add string attribute to skb
 109  *   nla_put_flag(skb, type)            add flag attribute to skb
 110  *   nla_put_msecs(skb, type, jiffies,
 111  *                 padattr)             add msecs attribute to skb
 112  *   nla_put_in_addr(skb, type, addr)   add IPv4 address attribute to skb
 113  *   nla_put_in6_addr(skb, type, addr)  add IPv6 address attribute to skb
 114  *
 115  * Nested Attributes Construction:
 116  *   nla_nest_start(skb, type)          start a nested attribute
 117  *   nla_nest_end(skb, nla)             finalize a nested attribute
 118  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 119  *
 120  * Attribute Length Calculations:
 121  *   nla_attr_size(payload)             length of attribute w/o padding
 122  *   nla_total_size(payload)            length of attribute w/ padding
 123  *   nla_padlen(payload)                length of padding
 124  *
 125  * Attribute Payload Access:
 126  *   nla_data(nla)                      head of attribute payload
 127  *   nla_len(nla)                       length of attribute payload
 128  *
 129  * Attribute Payload Access for Basic Types:
 130  *   nla_get_u8(nla)                    get payload for a u8 attribute
 131  *   nla_get_u16(nla)                   get payload for a u16 attribute
 132  *   nla_get_u32(nla)                   get payload for a u32 attribute
 133  *   nla_get_u64(nla)                   get payload for a u64 attribute
 134  *   nla_get_s8(nla)                    get payload for a s8 attribute
 135  *   nla_get_s16(nla)                   get payload for a s16 attribute
 136  *   nla_get_s32(nla)                   get payload for a s32 attribute
 137  *   nla_get_s64(nla)                   get payload for a s64 attribute
 138  *   nla_get_flag(nla)                  return 1 if flag is true
 139  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 140  *
 141  * Attribute Misc:
 142  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 143  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 144  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 145  *   nla_strcmp(nla, str)               compare attribute with string
 146  *
 147  * Attribute Parsing:
 148  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 149  *   nla_next(nla, remaining)           get next netlink attribute
 150  *   nla_validate()                     validate a stream of attributes
 151  *   nla_validate_nested()              validate a stream of nested attributes
 152  *   nla_find()                         find attribute in stream of attributes
 153  *   nla_find_nested()                  find attribute in nested attributes
 154  *   nla_parse()                        parse and validate stream of attrs
 155  *   nla_parse_nested()                 parse nested attribuets
 156  *   nla_for_each_attr()                loop over all attributes
 157  *   nla_for_each_nested()              loop over the nested attributes
 158  *=========================================================================
 159  */
 160
 161  /**
 162   * Standard attribute types to specify validation policy
 163   */
 164 enum {
 165         NLA_UNSPEC,
 166         NLA_U8,
 167         NLA_U16,
 168         NLA_U32,
 169         NLA_U64,
 170         NLA_STRING,
 171         NLA_FLAG,
 172         NLA_MSECS,
 173         NLA_NESTED,
 174         NLA_NESTED_COMPAT,
 175         NLA_NUL_STRING,
 176         NLA_BINARY,
 177         NLA_S8,
 178         NLA_S16,
 179         NLA_S32,
 180         NLA_S64,
 181         __NLA_TYPE_MAX,
 182 };
 183
 184 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 185
 186 /**
 187  * struct nla_policy - attribute validation policy
 188  * @type: Type of attribute or NLA_UNSPEC
 189  * @len: Type specific length of payload
 190  *
 191  * Policies are defined as arrays of this struct, the array must be
 192  * accessible by attribute type up to the highest identifier to be expected.
 193  *
 194  * Meaning of `len' field:
 195  *    NLA_STRING           Maximum length of string
 196  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 197  *    NLA_FLAG             Unused
 198  *    NLA_BINARY           Maximum length of attribute payload
 199  *    NLA_NESTED           Don't use `len' field -- length verification is
 200  *                         done by checking len of nested header (or empty)
 201  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 202  *    NLA_U8, NLA_U16,
 203  *    NLA_U32, NLA_U64,
 204  *    NLA_S8, NLA_S16,
 205  *    NLA_S32, NLA_S64,
 206  *    NLA_MSECS            Leaving the length field zero will verify the
 207  *                         given type fits, using it verifies minimum length
 208  *                         just like "All other"
 209  *    All other            Minimum length of attribute payload
 210  *
 211  * Example:
 212  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 213  *      [ATTR_FOO] = { .type = NLA_U16 },
 214  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 215  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 216  * };
 217  */
 218 struct nla_policy {
 219         u16             type;
 220         u16             len;
 221 };
 222
 223 /**
 224  * struct nl_info - netlink source information
 225  * @nlh: Netlink message header of original request
 226  * @portid: Netlink PORTID of requesting application
 227  */
 228 struct nl_info {
 229         struct nlmsghdr         *nlh;
 230         struct net              *nl_net;
 231         u32                     portid;
 232         bool                    skip_notify;
 233 };
 234
 235 int netlink_rcv_skb(struct sk_buff *skb,
 236                     int (*cb)(struct sk_buff *, struct nlmsghdr *,
 237                               struct netlink_ext_ack *));
 238 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 239                  unsigned int group, int report, gfp_t flags);
 240
 241 int nla_validate(const struct nlattr *head, int len, int maxtype,
 242                  const struct nla_policy *policy,
 243                  struct netlink_ext_ack *extack);
 244 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 245               int len, const struct nla_policy *policy,
 246               struct netlink_ext_ack *extack);
 247 int nla_policy_len(const struct nla_policy *, int);
 248 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 249 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 250 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 251 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 252 int nla_strcmp(const struct nlattr *nla, const char *str);
 253 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 254 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 255                                    int attrlen, int padattr);
 256 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 257 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 258 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 259                                  int attrlen, int padattr);
 260 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 261 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 262                const void *data);
 263 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 264                      const void *data, int padattr);
 265 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 266 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 267 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 268                   const void *data, int padattr);
 269 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 270 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 271
 272 /**************************************************************************
 273  * Netlink Messages
 274  **************************************************************************/
 275
 276 /**
 277  * nlmsg_msg_size - length of netlink message not including padding
 278  * @payload: length of message payload
 279  */
 280 static inline int nlmsg_msg_size(int payload)
 281 {
 282         return NLMSG_HDRLEN + payload;
 283 }
 284
 285 /**
 286  * nlmsg_total_size - length of netlink message including padding
 287  * @payload: length of message payload
 288  */
 289 static inline int nlmsg_total_size(int payload)
 290 {
 291         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 292 }
 293
 294 /**
 295  * nlmsg_padlen - length of padding at the message's tail
 296  * @payload: length of message payload
 297  */
 298 static inline int nlmsg_padlen(int payload)
 299 {
 300         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 301 }
 302
 303 /**
 304  * nlmsg_data - head of message payload
 305  * @nlh: netlink message header
 306  */
 307 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 308 {
 309         return (unsigned char *) nlh + NLMSG_HDRLEN;
 310 }
 311
 312 /**
 313  * nlmsg_len - length of message payload
 314  * @nlh: netlink message header
 315  */
 316 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 317 {
 318         return nlh->nlmsg_len - NLMSG_HDRLEN;
 319 }
 320
 321 /**
 322  * nlmsg_attrdata - head of attributes data
 323  * @nlh: netlink message header
 324  * @hdrlen: length of family specific header
 325  */
 326 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 327                                             int hdrlen)
 328 {
 329         unsigned char *data = nlmsg_data(nlh);
 330         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 331 }
 332
 333 /**
 334  * nlmsg_attrlen - length of attributes data
 335  * @nlh: netlink message header
 336  * @hdrlen: length of family specific header
 337  */
 338 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 339 {
 340         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 341 }
 342
 343 /**
 344  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 345  * @nlh: netlink message header
 346  * @remaining: number of bytes remaining in message stream
 347  */
 348 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 349 {
 350         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 351                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 352                 nlh->nlmsg_len <= remaining);
 353 }
 354
 355 /**
 356  * nlmsg_next - next netlink message in message stream
 357  * @nlh: netlink message header
 358  * @remaining: number of bytes remaining in message stream
 359  *
 360  * Returns the next netlink message in the message stream and
 361  * decrements remaining by the size of the current message.
 362  */
 363 static inline struct nlmsghdr *
 364 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 365 {
 366         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 367
 368         *remaining -= totlen;
 369
 370         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 371 }
 372
 373 /**
 374  * nlmsg_parse - parse attributes of a netlink message
 375  * @nlh: netlink message header
 376  * @hdrlen: length of family specific header
 377  * @tb: destination array with maxtype+1 elements
 378  * @maxtype: maximum attribute type to be expected
 379  * @policy: validation policy
 380  * @extack: extended ACK report struct
 381  *
 382  * See nla_parse()
 383  */
 384 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 385                               struct nlattr *tb[], int maxtype,
 386                               const struct nla_policy *policy,
 387                               struct netlink_ext_ack *extack)
 388 {
 389         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 390                 return -EINVAL;
 391
 392         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 393                          nlmsg_attrlen(nlh, hdrlen), policy, extack);
 394 }
 395
 396 /**
 397  * nlmsg_find_attr - find a specific attribute in a netlink message
 398  * @nlh: netlink message header
 399  * @hdrlen: length of familiy specific header
 400  * @attrtype: type of attribute to look for
 401  *
 402  * Returns the first attribute which matches the specified type.
 403  */
 404 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 405                                              int hdrlen, int attrtype)
 406 {
 407         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 408                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 409 }
 410
 411 /**
 412  * nlmsg_validate - validate a netlink message including attributes
 413  * @nlh: netlinket message header
 414  * @hdrlen: length of familiy specific header
 415  * @maxtype: maximum attribute type to be expected
 416  * @policy: validation policy
 417  * @extack: extended ACK report struct
 418  */
 419 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 420                                  int hdrlen, int maxtype,
 421                                  const struct nla_policy *policy,
 422                                  struct netlink_ext_ack *extack)
 423 {
 424         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 425                 return -EINVAL;
 426
 427         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 428                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy,
 429                             extack);
 430 }
 431
 432 /**
 433  * nlmsg_report - need to report back to application?
 434  * @nlh: netlink message header
 435  *
 436  * Returns 1 if a report back to the application is requested.
 437  */
 438 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 439 {
 440         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 441 }
 442
 443 /**
 444  * nlmsg_for_each_attr - iterate over a stream of attributes
 445  * @pos: loop counter, set to current attribute
 446  * @nlh: netlink message header
 447  * @hdrlen: length of familiy specific header
 448  * @rem: initialized to len, holds bytes currently remaining in stream
 449  */
 450 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 451         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 452                           nlmsg_attrlen(nlh, hdrlen), rem)
 453
 454 /**
 455  * nlmsg_put - Add a new netlink message to an skb
 456  * @skb: socket buffer to store message in
 457  * @portid: netlink PORTID of requesting application
 458  * @seq: sequence number of message
 459  * @type: message type
 460  * @payload: length of message payload
 461  * @flags: message flags
 462  *
 463  * Returns NULL if the tailroom of the skb is insufficient to store
 464  * the message header and payload.
 465  */
 466 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 467                                          int type, int payload, int flags)
 468 {
 469         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 470                 return NULL;
 471
 472         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 473 }
 474
 475 /**
 476  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 477  * @skb: socket buffer to store message in
 478  * @cb: netlink callback
 479  * @type: message type
 480  * @payload: length of message payload
 481  * @flags: message flags
 482  *
 483  * Returns NULL if the tailroom of the skb is insufficient to store
 484  * the message header and payload.
 485  */
 486 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 487                                                 struct netlink_callback *cb,
 488                                                 int type, int payload,
 489                                                 int flags)
 490 {
 491         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 492                          type, payload, flags);
 493 }
 494
 495 /**
 496  * nlmsg_new - Allocate a new netlink message
 497  * @payload: size of the message payload
 498  * @flags: the type of memory to allocate.
 499  *
 500  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 501  * and a good default is needed.
 502  */
 503 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 504 {
 505         return alloc_skb(nlmsg_total_size(payload), flags);
 506 }
 507
 508 /**
 509  * nlmsg_end - Finalize a netlink message
 510  * @skb: socket buffer the message is stored in
 511  * @nlh: netlink message header
 512  *
 513  * Corrects the netlink message header to include the appeneded
 514  * attributes. Only necessary if attributes have been added to
 515  * the message.
 516  */
 517 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 518 {
 519         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 520 }
 521
 522 /**
 523  * nlmsg_get_pos - return current position in netlink message
 524  * @skb: socket buffer the message is stored in
 525  *
 526  * Returns a pointer to the current tail of the message.
 527  */
 528 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 529 {
 530         return skb_tail_pointer(skb);
 531 }
 532
 533 /**
 534  * nlmsg_trim - Trim message to a mark
 535  * @skb: socket buffer the message is stored in
 536  * @mark: mark to trim to
 537  *
 538  * Trims the message to the provided mark.
 539  */
 540 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 541 {
 542         if (mark) {
 543                 WARN_ON((unsigned char *) mark < skb->data);
 544                 skb_trim(skb, (unsigned char *) mark - skb->data);
 545         }
 546 }
 547
 548 /**
 549  * nlmsg_cancel - Cancel construction of a netlink message
 550  * @skb: socket buffer the message is stored in
 551  * @nlh: netlink message header
 552  *
 553  * Removes the complete netlink message including all
 554  * attributes from the socket buffer again.
 555  */
 556 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 557 {
 558         nlmsg_trim(skb, nlh);
 559 }
 560
 561 /**
 562  * nlmsg_free - free a netlink message
 563  * @skb: socket buffer of netlink message
 564  */
 565 static inline void nlmsg_free(struct sk_buff *skb)
 566 {
 567         kfree_skb(skb);
 568 }
 569
 570 /**
 571  * nlmsg_multicast - multicast a netlink message
 572  * @sk: netlink socket to spread messages to
 573  * @skb: netlink message as socket buffer
 574  * @portid: own netlink portid to avoid sending to yourself
 575  * @group: multicast group id
 576  * @flags: allocation flags
 577  */
 578 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 579                                   u32 portid, unsigned int group, gfp_t flags)
 580 {
 581         int err;
 582
 583         NETLINK_CB(skb).dst_group = group;
 584
 585         err = netlink_broadcast(sk, skb, portid, group, flags);
 586         if (err > 0)
 587                 err = 0;
 588
 589         return err;
 590 }
 591
 592 /**
 593  * nlmsg_unicast - unicast a netlink message
 594  * @sk: netlink socket to spread message to
 595  * @skb: netlink message as socket buffer
 596  * @portid: netlink portid of the destination socket
 597  */
 598 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 599 {
 600         int err;
 601
 602         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 603         if (err > 0)
 604                 err = 0;
 605
 606         return err;
 607 }
 608
 609 /**
 610  * nlmsg_for_each_msg - iterate over a stream of messages
 611  * @pos: loop counter, set to current message
 612  * @head: head of message stream
 613  * @len: length of message stream
 614  * @rem: initialized to len, holds bytes currently remaining in stream
 615  */
 616 #define nlmsg_for_each_msg(pos, head, len, rem) \
 617         for (pos = head, rem = len; \
 618              nlmsg_ok(pos, rem); \
 619              pos = nlmsg_next(pos, &(rem)))
 620
 621 /**
 622  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 623  * @cb: netlink callback structure that stores the sequence number
 624  * @nlh: netlink message header to write the flag to
 625  *
 626  * This function checks if the sequence (generation) number changed during dump
 627  * and if it did, advertises it in the netlink message header.
 628  *
 629  * The correct way to use it is to set cb->seq to the generation counter when
 630  * all locks for dumping have been acquired, and then call this function for
 631  * each message that is generated.
 632  *
 633  * Note that due to initialisation concerns, 0 is an invalid sequence number
 634  * and must not be used by code that uses this functionality.
 635  */
 636 static inline void
 637 nl_dump_check_consistent(struct netlink_callback *cb,
 638                          struct nlmsghdr *nlh)
 639 {
 640         if (cb->prev_seq && cb->seq != cb->prev_seq)
 641                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 642         cb->prev_seq = cb->seq;
 643 }
 644
 645 /**************************************************************************
 646  * Netlink Attributes
 647  **************************************************************************/
 648
 649 /**
 650  * nla_attr_size - length of attribute not including padding
 651  * @payload: length of payload
 652  */
 653 static inline int nla_attr_size(int payload)
 654 {
 655         return NLA_HDRLEN + payload;
 656 }
 657
 658 /**
 659  * nla_total_size - total length of attribute including padding
 660  * @payload: length of payload
 661  */
 662 static inline int nla_total_size(int payload)
 663 {
 664         return NLA_ALIGN(nla_attr_size(payload));
 665 }
 666
 667 /**
 668  * nla_padlen - length of padding at the tail of attribute
 669  * @payload: length of payload
 670  */
 671 static inline int nla_padlen(int payload)
 672 {
 673         return nla_total_size(payload) - nla_attr_size(payload);
 674 }
 675
 676 /**
 677  * nla_type - attribute type
 678  * @nla: netlink attribute
 679  */
 680 static inline int nla_type(const struct nlattr *nla)
 681 {
 682         return nla->nla_type & NLA_TYPE_MASK;
 683 }
 684
 685 /**
 686  * nla_data - head of payload
 687  * @nla: netlink attribute
 688  */
 689 static inline void *nla_data(const struct nlattr *nla)
 690 {
 691         return (char *) nla + NLA_HDRLEN;
 692 }
 693
 694 /**
 695  * nla_len - length of payload
 696  * @nla: netlink attribute
 697  */
 698 static inline int nla_len(const struct nlattr *nla)
 699 {
 700         return nla->nla_len - NLA_HDRLEN;
 701 }
 702
 703 /**
 704  * nla_ok - check if the netlink attribute fits into the remaining bytes
 705  * @nla: netlink attribute
 706  * @remaining: number of bytes remaining in attribute stream
 707  */
 708 static inline int nla_ok(const struct nlattr *nla, int remaining)
 709 {
 710         return remaining >= (int) sizeof(*nla) &&
 711                nla->nla_len >= sizeof(*nla) &&
 712                nla->nla_len <= remaining;
 713 }
 714
 715 /**
 716  * nla_next - next netlink attribute in attribute stream
 717  * @nla: netlink attribute
 718  * @remaining: number of bytes remaining in attribute stream
 719  *
 720  * Returns the next netlink attribute in the attribute stream and
 721  * decrements remaining by the size of the current attribute.
 722  */
 723 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 724 {
 725         unsigned int totlen = NLA_ALIGN(nla->nla_len);
 726
 727         *remaining -= totlen;
 728         return (struct nlattr *) ((char *) nla + totlen);
 729 }
 730
 731 /**
 732  * nla_find_nested - find attribute in a set of nested attributes
 733  * @nla: attribute containing the nested attributes
 734  * @attrtype: type of attribute to look for
 735  *
 736  * Returns the first attribute which matches the specified type.
 737  */
 738 static inline struct nlattr *
 739 nla_find_nested(const struct nlattr *nla, int attrtype)
 740 {
 741         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 742 }
 743
 744 /**
 745  * nla_parse_nested - parse nested attributes
 746  * @tb: destination array with maxtype+1 elements
 747  * @maxtype: maximum attribute type to be expected
 748  * @nla: attribute containing the nested attributes
 749  * @policy: validation policy
 750  * @extack: extended ACK report struct
 751  *
 752  * See nla_parse()
 753  */
 754 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 755                                    const struct nlattr *nla,
 756                                    const struct nla_policy *policy,
 757                                    struct netlink_ext_ack *extack)
 758 {
 759         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
 760                          extack);
 761 }
 762
 763 /**
 764  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 765  * @skb: socket buffer to add attribute to
 766  * @attrtype: attribute type
 767  * @value: numeric value
 768  */
 769 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 770 {
 771         return nla_put(skb, attrtype, sizeof(u8), &value);
 772 }
 773
 774 /**
 775  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 776  * @skb: socket buffer to add attribute to
 777  * @attrtype: attribute type
 778  * @value: numeric value
 779  */
 780 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 781 {
 782         return nla_put(skb, attrtype, sizeof(u16), &value);
 783 }
 784
 785 /**
 786  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 787  * @skb: socket buffer to add attribute to
 788  * @attrtype: attribute type
 789  * @value: numeric value
 790  */
 791 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 792 {
 793         return nla_put(skb, attrtype, sizeof(__be16), &value);
 794 }
 795
 796 /**
 797  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 798  * @skb: socket buffer to add attribute to
 799  * @attrtype: attribute type
 800  * @value: numeric value
 801  */
 802 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 803 {
 804         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 805 }
 806
 807 /**
 808  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 809  * @skb: socket buffer to add attribute to
 810  * @attrtype: attribute type
 811  * @value: numeric value
 812  */
 813 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 814 {
 815         return nla_put(skb, attrtype, sizeof(__le16), &value);
 816 }
 817
 818 /**
 819  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 820  * @skb: socket buffer to add attribute to
 821  * @attrtype: attribute type
 822  * @value: numeric value
 823  */
 824 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 825 {
 826         return nla_put(skb, attrtype, sizeof(u32), &value);
 827 }
 828
 829 /**
 830  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 831  * @skb: socket buffer to add attribute to
 832  * @attrtype: attribute type
 833  * @value: numeric value
 834  */
 835 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 836 {
 837         return nla_put(skb, attrtype, sizeof(__be32), &value);
 838 }
 839
 840 /**
 841  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 842  * @skb: socket buffer to add attribute to
 843  * @attrtype: attribute type
 844  * @value: numeric value
 845  */
 846 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 847 {
 848         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 849 }
 850
 851 /**
 852  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 853  * @skb: socket buffer to add attribute to
 854  * @attrtype: attribute type
 855  * @value: numeric value
 856  */
 857 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 858 {
 859         return nla_put(skb, attrtype, sizeof(__le32), &value);
 860 }
 861
 862 /**
 863  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
 864  * @skb: socket buffer to add attribute to
 865  * @attrtype: attribute type
 866  * @value: numeric value
 867  * @padattr: attribute type for the padding
 868  */
 869 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
 870                                     u64 value, int padattr)
 871 {
 872         return nla_put_64bit(skb, attrtype, sizeof(u64), &value, padattr);
 873 }
 874
 875 /**
 876  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 877  * @skb: socket buffer to add attribute to
 878  * @attrtype: attribute type
 879  * @value: numeric value
 880  * @padattr: attribute type for the padding
 881  */
 882 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
 883                                int padattr)
 884 {
 885         return nla_put_64bit(skb, attrtype, sizeof(__be64), &value, padattr);
 886 }
 887
 888 /**
 889  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
 890  * @skb: socket buffer to add attribute to
 891  * @attrtype: attribute type
 892  * @value: numeric value
 893  * @padattr: attribute type for the padding
 894  */
 895 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
 896                                 int padattr)
 897 {
 898         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value,
 899                             padattr);
 900 }
 901
 902 /**
 903  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 904  * @skb: socket buffer to add attribute to
 905  * @attrtype: attribute type
 906  * @value: numeric value
 907  * @padattr: attribute type for the padding
 908  */
 909 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
 910                                int padattr)
 911 {
 912         return nla_put_64bit(skb, attrtype, sizeof(__le64), &value, padattr);
 913 }
 914
 915 /**
 916  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 917  * @skb: socket buffer to add attribute to
 918  * @attrtype: attribute type
 919  * @value: numeric value
 920  */
 921 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 922 {
 923         return nla_put(skb, attrtype, sizeof(s8), &value);
 924 }
 925
 926 /**
 927  * nla_put_s16 - Add a s16 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_s16(struct sk_buff *skb, int attrtype, s16 value)
 933 {
 934         return nla_put(skb, attrtype, sizeof(s16), &value);
 935 }
 936
 937 /**
 938  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 939  * @skb: socket buffer to add attribute to
 940  * @attrtype: attribute type
 941  * @value: numeric value
 942  */
 943 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 944 {
 945         return nla_put(skb, attrtype, sizeof(s32), &value);
 946 }
 947
 948 /**
 949  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 950  * @skb: socket buffer to add attribute to
 951  * @attrtype: attribute type
 952  * @value: numeric value
 953  * @padattr: attribute type for the padding
 954  */
 955 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
 956                               int padattr)
 957 {
 958         return nla_put_64bit(skb, attrtype, sizeof(s64), &value, padattr);
 959 }
 960
 961 /**
 962  * nla_put_string - Add a string netlink attribute to a socket buffer
 963  * @skb: socket buffer to add attribute to
 964  * @attrtype: attribute type
 965  * @str: NUL terminated string
 966  */
 967 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 968                                  const char *str)
 969 {
 970         return nla_put(skb, attrtype, strlen(str) + 1, str);
 971 }
 972
 973 /**
 974  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 975  * @skb: socket buffer to add attribute to
 976  * @attrtype: attribute type
 977  */
 978 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 979 {
 980         return nla_put(skb, attrtype, 0, NULL);
 981 }
 982
 983 /**
 984  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
 985  * @skb: socket buffer to add attribute to
 986  * @attrtype: attribute type
 987  * @njiffies: number of jiffies to convert to msecs
 988  * @padattr: attribute type for the padding
 989  */
 990 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 991                                 unsigned long njiffies, int padattr)
 992 {
 993         u64 tmp = jiffies_to_msecs(njiffies);
 994
 995         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
 996 }
 997
 998 /**
 999  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
1000  * buffer
1001  * @skb: socket buffer to add attribute to
1002  * @attrtype: attribute type
1003  * @addr: IPv4 address
1004  */
1005 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1006                                   __be32 addr)
1007 {
1008         return nla_put_be32(skb, attrtype, addr);
1009 }
1010
1011 /**
1012  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1013  * buffer
1014  * @skb: socket buffer to add attribute to
1015  * @attrtype: attribute type
1016  * @addr: IPv6 address
1017  */
1018 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1019                                    const struct in6_addr *addr)
1020 {
1021         return nla_put(skb, attrtype, sizeof(*addr), addr);
1022 }
1023
1024 /**
1025  * nla_get_u32 - return payload of u32 attribute
1026  * @nla: u32 netlink attribute
1027  */
1028 static inline u32 nla_get_u32(const struct nlattr *nla)
1029 {
1030         return *(u32 *) nla_data(nla);
1031 }
1032
1033 /**
1034  * nla_get_be32 - return payload of __be32 attribute
1035  * @nla: __be32 netlink attribute
1036  */
1037 static inline __be32 nla_get_be32(const struct nlattr *nla)
1038 {
1039         return *(__be32 *) nla_data(nla);
1040 }
1041
1042 /**
1043  * nla_get_le32 - return payload of __le32 attribute
1044  * @nla: __le32 netlink attribute
1045  */
1046 static inline __le32 nla_get_le32(const struct nlattr *nla)
1047 {
1048         return *(__le32 *) nla_data(nla);
1049 }
1050
1051 /**
1052  * nla_get_u16 - return payload of u16 attribute
1053  * @nla: u16 netlink attribute
1054  */
1055 static inline u16 nla_get_u16(const struct nlattr *nla)
1056 {
1057         return *(u16 *) nla_data(nla);
1058 }
1059
1060 /**
1061  * nla_get_be16 - return payload of __be16 attribute
1062  * @nla: __be16 netlink attribute
1063  */
1064 static inline __be16 nla_get_be16(const struct nlattr *nla)
1065 {
1066         return *(__be16 *) nla_data(nla);
1067 }
1068
1069 /**
1070  * nla_get_le16 - return payload of __le16 attribute
1071  * @nla: __le16 netlink attribute
1072  */
1073 static inline __le16 nla_get_le16(const struct nlattr *nla)
1074 {
1075         return *(__le16 *) nla_data(nla);
1076 }
1077
1078 /**
1079  * nla_get_u8 - return payload of u8 attribute
1080  * @nla: u8 netlink attribute
1081  */
1082 static inline u8 nla_get_u8(const struct nlattr *nla)
1083 {
1084         return *(u8 *) nla_data(nla);
1085 }
1086
1087 /**
1088  * nla_get_u64 - return payload of u64 attribute
1089  * @nla: u64 netlink attribute
1090  */
1091 static inline u64 nla_get_u64(const struct nlattr *nla)
1092 {
1093         u64 tmp;
1094
1095         nla_memcpy(&tmp, nla, sizeof(tmp));
1096
1097         return tmp;
1098 }
1099
1100 /**
1101  * nla_get_be64 - return payload of __be64 attribute
1102  * @nla: __be64 netlink attribute
1103  */
1104 static inline __be64 nla_get_be64(const struct nlattr *nla)
1105 {
1106         __be64 tmp;
1107
1108         nla_memcpy(&tmp, nla, sizeof(tmp));
1109
1110         return tmp;
1111 }
1112
1113 /**
1114  * nla_get_le64 - return payload of __le64 attribute
1115  * @nla: __le64 netlink attribute
1116  */
1117 static inline __le64 nla_get_le64(const struct nlattr *nla)
1118 {
1119         return *(__le64 *) nla_data(nla);
1120 }
1121
1122 /**
1123  * nla_get_s32 - return payload of s32 attribute
1124  * @nla: s32 netlink attribute
1125  */
1126 static inline s32 nla_get_s32(const struct nlattr *nla)
1127 {
1128         return *(s32 *) nla_data(nla);
1129 }
1130
1131 /**
1132  * nla_get_s16 - return payload of s16 attribute
1133  * @nla: s16 netlink attribute
1134  */
1135 static inline s16 nla_get_s16(const struct nlattr *nla)
1136 {
1137         return *(s16 *) nla_data(nla);
1138 }
1139
1140 /**
1141  * nla_get_s8 - return payload of s8 attribute
1142  * @nla: s8 netlink attribute
1143  */
1144 static inline s8 nla_get_s8(const struct nlattr *nla)
1145 {
1146         return *(s8 *) nla_data(nla);
1147 }
1148
1149 /**
1150  * nla_get_s64 - return payload of s64 attribute
1151  * @nla: s64 netlink attribute
1152  */
1153 static inline s64 nla_get_s64(const struct nlattr *nla)
1154 {
1155         s64 tmp;
1156
1157         nla_memcpy(&tmp, nla, sizeof(tmp));
1158
1159         return tmp;
1160 }
1161
1162 /**
1163  * nla_get_flag - return payload of flag attribute
1164  * @nla: flag netlink attribute
1165  */
1166 static inline int nla_get_flag(const struct nlattr *nla)
1167 {
1168         return !!nla;
1169 }
1170
1171 /**
1172  * nla_get_msecs - return payload of msecs attribute
1173  * @nla: msecs netlink attribute
1174  *
1175  * Returns the number of milliseconds in jiffies.
1176  */
1177 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1178 {
1179         u64 msecs = nla_get_u64(nla);
1180
1181         return msecs_to_jiffies((unsigned long) msecs);
1182 }
1183
1184 /**
1185  * nla_get_in_addr - return payload of IPv4 address attribute
1186  * @nla: IPv4 address netlink attribute
1187  */
1188 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1189 {
1190         return *(__be32 *) nla_data(nla);
1191 }
1192
1193 /**
1194  * nla_get_in6_addr - return payload of IPv6 address attribute
1195  * @nla: IPv6 address netlink attribute
1196  */
1197 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1198 {
1199         struct in6_addr tmp;
1200
1201         nla_memcpy(&tmp, nla, sizeof(tmp));
1202         return tmp;
1203 }
1204
1205 /**
1206  * nla_memdup - duplicate attribute memory (kmemdup)
1207  * @src: netlink attribute to duplicate from
1208  * @gfp: GFP mask
1209  */
1210 static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
1211 {
1212         return kmemdup(nla_data(src), nla_len(src), gfp);
1213 }
1214
1215 /**
1216  * nla_nest_start - Start a new level of nested attributes
1217  * @skb: socket buffer to add attributes to
1218  * @attrtype: attribute type of container
1219  *
1220  * Returns the container attribute
1221  */
1222 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1223 {
1224         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1225
1226         if (nla_put(skb, attrtype, 0, NULL) < 0)
1227                 return NULL;
1228
1229         return start;
1230 }
1231
1232 /**
1233  * nla_nest_end - Finalize nesting of attributes
1234  * @skb: socket buffer the attributes are stored in
1235  * @start: container attribute
1236  *
1237  * Corrects the container attribute header to include the all
1238  * appeneded attributes.
1239  *
1240  * Returns the total data length of the skb.
1241  */
1242 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1243 {
1244         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1245         return skb->len;
1246 }
1247
1248 /**
1249  * nla_nest_cancel - Cancel nesting of attributes
1250  * @skb: socket buffer the message is stored in
1251  * @start: container attribute
1252  *
1253  * Removes the container attribute and including all nested
1254  * attributes. Returns -EMSGSIZE
1255  */
1256 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1257 {
1258         nlmsg_trim(skb, start);
1259 }
1260
1261 /**
1262  * nla_validate_nested - Validate a stream of nested attributes
1263  * @start: container attribute
1264  * @maxtype: maximum attribute type to be expected
1265  * @policy: validation policy
1266  * @extack: extended ACK report struct
1267  *
1268  * Validates all attributes in the nested attribute stream against the
1269  * specified policy. Attributes with a type exceeding maxtype will be
1270  * ignored. See documenation of struct nla_policy for more details.
1271  *
1272  * Returns 0 on success or a negative error code.
1273  */
1274 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1275                                       const struct nla_policy *policy,
1276                                       struct netlink_ext_ack *extack)
1277 {
1278         return nla_validate(nla_data(start), nla_len(start), maxtype, policy,
1279                             extack);
1280 }
1281
1282 /**
1283  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1284  * @skb: socket buffer the message is stored in
1285  *
1286  * Return true if padding is needed to align the next attribute (nla_data()) to
1287  * a 64-bit aligned area.
1288  */
1289 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1290 {
1291 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1292         /* The nlattr header is 4 bytes in size, that's why we test
1293          * if the skb->data _is_ aligned.  A NOP attribute, plus
1294          * nlattr header for next attribute, will make nla_data()
1295          * 8-byte aligned.
1296          */
1297         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1298                 return true;
1299 #endif
1300         return false;
1301 }
1302
1303 /**
1304  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1305  * @skb: socket buffer the message is stored in
1306  * @padattr: attribute type for the padding
1307  *
1308  * Conditionally emit a padding netlink attribute in order to make
1309  * the next attribute we emit have a 64-bit aligned nla_data() area.
1310  * This will only be done in architectures which do not have
1311  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1312  *
1313  * Returns zero on success or a negative error code.
1314  */
1315 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1316 {
1317         if (nla_need_padding_for_64bit(skb) &&
1318             !nla_reserve(skb, padattr, 0))
1319                 return -EMSGSIZE;
1320
1321         return 0;
1322 }
1323
1324 /**
1325  * nla_total_size_64bit - total length of attribute including padding
1326  * @payload: length of payload
1327  */
1328 static inline int nla_total_size_64bit(int payload)
1329 {
1330         return NLA_ALIGN(nla_attr_size(payload))
1331 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1332                 + NLA_ALIGN(nla_attr_size(0))
1333 #endif
1334                 ;
1335 }
1336
1337 /**
1338  * nla_for_each_attr - iterate over a stream of attributes
1339  * @pos: loop counter, set to current attribute
1340  * @head: head of attribute stream
1341  * @len: length of attribute stream
1342  * @rem: initialized to len, holds bytes currently remaining in stream
1343  */
1344 #define nla_for_each_attr(pos, head, len, rem) \
1345         for (pos = head, rem = len; \
1346              nla_ok(pos, rem); \
1347              pos = nla_next(pos, &(rem)))
1348
1349 /**
1350  * nla_for_each_nested - iterate over nested attributes
1351  * @pos: loop counter, set to current attribute
1352  * @nla: attribute containing the nested attributes
1353  * @rem: initialized to len, holds bytes currently remaining in stream
1354  */
1355 #define nla_for_each_nested(pos, nla, rem) \
1356         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1357
1358 /**
1359  * nla_is_last - Test if attribute is last in stream
1360  * @nla: attribute to test
1361  * @rem: bytes remaining in stream
1362  */
1363 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1364 {
1365         return nla->nla_len == rem;
1366 }
1367
1368 #endif