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(skb, type, value)      add u64 attribute to skb
 102  *   nla_put_s8(skb, type, value)       add s8 attribute to skb
 103  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
 104  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
 105  *   nla_put_s64(skb, type, value,
 106  *               padattr)               add s64 attribute to skb
 107  *   nla_put_string(skb, type, str)     add string attribute to skb
 108  *   nla_put_flag(skb, type)            add flag attribute to skb
 109  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 110  *   nla_put_in_addr(skb, type, addr)   add IPv4 address attribute to skb
 111  *   nla_put_in6_addr(skb, type, addr)  add IPv6 address attribute to skb
 112  *
 113  * Nested Attributes Construction:
 114  *   nla_nest_start(skb, type)          start a nested attribute
 115  *   nla_nest_end(skb, nla)             finalize a nested attribute
 116  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 117  *
 118  * Attribute Length Calculations:
 119  *   nla_attr_size(payload)             length of attribute w/o padding
 120  *   nla_total_size(payload)            length of attribute w/ padding
 121  *   nla_padlen(payload)                length of padding
 122  *
 123  * Attribute Payload Access:
 124  *   nla_data(nla)                      head of attribute payload
 125  *   nla_len(nla)                       length of attribute payload
 126  *
 127  * Attribute Payload Access for Basic Types:
 128  *   nla_get_u8(nla)                    get payload for a u8 attribute
 129  *   nla_get_u16(nla)                   get payload for a u16 attribute
 130  *   nla_get_u32(nla)                   get payload for a u32 attribute
 131  *   nla_get_u64(nla)                   get payload for a u64 attribute
 132  *   nla_get_s8(nla)                    get payload for a s8 attribute
 133  *   nla_get_s16(nla)                   get payload for a s16 attribute
 134  *   nla_get_s32(nla)                   get payload for a s32 attribute
 135  *   nla_get_s64(nla)                   get payload for a s64 attribute
 136  *   nla_get_flag(nla)                  return 1 if flag is true
 137  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 138  *
 139  * Attribute Misc:
 140  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 141  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 142  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 143  *   nla_strcmp(nla, str)               compare attribute with string
 144  *
 145  * Attribute Parsing:
 146  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 147  *   nla_next(nla, remaining)           get next netlink attribute
 148  *   nla_validate()                     validate a stream of attributes
 149  *   nla_validate_nested()              validate a stream of nested attributes
 150  *   nla_find()                         find attribute in stream of attributes
 151  *   nla_find_nested()                  find attribute in nested attributes
 152  *   nla_parse()                        parse and validate stream of attrs
 153  *   nla_parse_nested()                 parse nested attribuets
 154  *   nla_for_each_attr()                loop over all attributes
 155  *   nla_for_each_nested()              loop over the nested attributes
 156  *=========================================================================
 157  */
 158
 159  /**
 160   * Standard attribute types to specify validation policy
 161   */
 162 enum {
 163         NLA_UNSPEC,
 164         NLA_U8,
 165         NLA_U16,
 166         NLA_U32,
 167         NLA_U64,
 168         NLA_STRING,
 169         NLA_FLAG,
 170         NLA_MSECS,
 171         NLA_NESTED,
 172         NLA_NESTED_COMPAT,
 173         NLA_NUL_STRING,
 174         NLA_BINARY,
 175         NLA_S8,
 176         NLA_S16,
 177         NLA_S32,
 178         NLA_S64,
 179         __NLA_TYPE_MAX,
 180 };
 181
 182 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 183
 184 /**
 185  * struct nla_policy - attribute validation policy
 186  * @type: Type of attribute or NLA_UNSPEC
 187  * @len: Type specific length of payload
 188  *
 189  * Policies are defined as arrays of this struct, the array must be
 190  * accessible by attribute type up to the highest identifier to be expected.
 191  *
 192  * Meaning of `len' field:
 193  *    NLA_STRING           Maximum length of string
 194  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 195  *    NLA_FLAG             Unused
 196  *    NLA_BINARY           Maximum length of attribute payload
 197  *    NLA_NESTED           Don't use `len' field -- length verification is
 198  *                         done by checking len of nested header (or empty)
 199  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 200  *    NLA_U8, NLA_U16,
 201  *    NLA_U32, NLA_U64,
 202  *    NLA_S8, NLA_S16,
 203  *    NLA_S32, NLA_S64,
 204  *    NLA_MSECS            Leaving the length field zero will verify the
 205  *                         given type fits, using it verifies minimum length
 206  *                         just like "All other"
 207  *    All other            Minimum length of attribute payload
 208  *
 209  * Example:
 210  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 211  *      [ATTR_FOO] = { .type = NLA_U16 },
 212  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 213  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 214  * };
 215  */
 216 struct nla_policy {
 217         u16             type;
 218         u16             len;
 219 };
 220
 221 /**
 222  * struct nl_info - netlink source information
 223  * @nlh: Netlink message header of original request
 224  * @portid: Netlink PORTID of requesting application
 225  */
 226 struct nl_info {
 227         struct nlmsghdr         *nlh;
 228         struct net              *nl_net;
 229         u32                     portid;
 230 };
 231
 232 int netlink_rcv_skb(struct sk_buff *skb,
 233                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
 234 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 235                  unsigned int group, int report, gfp_t flags);
 236
 237 int nla_validate(const struct nlattr *head, int len, int maxtype,
 238                  const struct nla_policy *policy);
 239 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 240               int len, const struct nla_policy *policy);
 241 int nla_policy_len(const struct nla_policy *, int);
 242 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 243 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 244 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 245 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 246 int nla_strcmp(const struct nlattr *nla, const char *str);
 247 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 248 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 249                                    int attrlen, int padattr);
 250 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 251 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 252 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 253                                  int attrlen, int padattr);
 254 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 255 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 256                const void *data);
 257 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 258                      const void *data, int padattr);
 259 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 260 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 261 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 262                   const void *data, int padattr);
 263 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 264 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 265
 266 /**************************************************************************
 267  * Netlink Messages
 268  **************************************************************************/
 269
 270 /**
 271  * nlmsg_msg_size - length of netlink message not including padding
 272  * @payload: length of message payload
 273  */
 274 static inline int nlmsg_msg_size(int payload)
 275 {
 276         return NLMSG_HDRLEN + payload;
 277 }
 278
 279 /**
 280  * nlmsg_total_size - length of netlink message including padding
 281  * @payload: length of message payload
 282  */
 283 static inline int nlmsg_total_size(int payload)
 284 {
 285         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 286 }
 287
 288 /**
 289  * nlmsg_padlen - length of padding at the message's tail
 290  * @payload: length of message payload
 291  */
 292 static inline int nlmsg_padlen(int payload)
 293 {
 294         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 295 }
 296
 297 /**
 298  * nlmsg_data - head of message payload
 299  * @nlh: netlink message header
 300  */
 301 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 302 {
 303         return (unsigned char *) nlh + NLMSG_HDRLEN;
 304 }
 305
 306 /**
 307  * nlmsg_len - length of message payload
 308  * @nlh: netlink message header
 309  */
 310 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 311 {
 312         return nlh->nlmsg_len - NLMSG_HDRLEN;
 313 }
 314
 315 /**
 316  * nlmsg_attrdata - head of attributes data
 317  * @nlh: netlink message header
 318  * @hdrlen: length of family specific header
 319  */
 320 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 321                                             int hdrlen)
 322 {
 323         unsigned char *data = nlmsg_data(nlh);
 324         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 325 }
 326
 327 /**
 328  * nlmsg_attrlen - length of attributes data
 329  * @nlh: netlink message header
 330  * @hdrlen: length of family specific header
 331  */
 332 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 333 {
 334         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 335 }
 336
 337 /**
 338  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 339  * @nlh: netlink message header
 340  * @remaining: number of bytes remaining in message stream
 341  */
 342 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 343 {
 344         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 345                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 346                 nlh->nlmsg_len <= remaining);
 347 }
 348
 349 /**
 350  * nlmsg_next - next netlink message in message stream
 351  * @nlh: netlink message header
 352  * @remaining: number of bytes remaining in message stream
 353  *
 354  * Returns the next netlink message in the message stream and
 355  * decrements remaining by the size of the current message.
 356  */
 357 static inline struct nlmsghdr *
 358 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 359 {
 360         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 361
 362         *remaining -= totlen;
 363
 364         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 365 }
 366
 367 /**
 368  * nlmsg_parse - parse attributes of a netlink message
 369  * @nlh: netlink message header
 370  * @hdrlen: length of family specific header
 371  * @tb: destination array with maxtype+1 elements
 372  * @maxtype: maximum attribute type to be expected
 373  * @policy: validation policy
 374  *
 375  * See nla_parse()
 376  */
 377 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 378                               struct nlattr *tb[], int maxtype,
 379                               const struct nla_policy *policy)
 380 {
 381         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 382                 return -EINVAL;
 383
 384         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 385                          nlmsg_attrlen(nlh, hdrlen), policy);
 386 }
 387
 388 /**
 389  * nlmsg_find_attr - find a specific attribute in a netlink message
 390  * @nlh: netlink message header
 391  * @hdrlen: length of familiy specific header
 392  * @attrtype: type of attribute to look for
 393  *
 394  * Returns the first attribute which matches the specified type.
 395  */
 396 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 397                                              int hdrlen, int attrtype)
 398 {
 399         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 400                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 401 }
 402
 403 /**
 404  * nlmsg_validate - validate a netlink message including attributes
 405  * @nlh: netlinket message header
 406  * @hdrlen: length of familiy specific header
 407  * @maxtype: maximum attribute type to be expected
 408  * @policy: validation policy
 409  */
 410 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 411                                  int hdrlen, int maxtype,
 412                                  const struct nla_policy *policy)
 413 {
 414         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 415                 return -EINVAL;
 416
 417         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 418                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 419 }
 420
 421 /**
 422  * nlmsg_report - need to report back to application?
 423  * @nlh: netlink message header
 424  *
 425  * Returns 1 if a report back to the application is requested.
 426  */
 427 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 428 {
 429         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 430 }
 431
 432 /**
 433  * nlmsg_for_each_attr - iterate over a stream of attributes
 434  * @pos: loop counter, set to current attribute
 435  * @nlh: netlink message header
 436  * @hdrlen: length of familiy specific header
 437  * @rem: initialized to len, holds bytes currently remaining in stream
 438  */
 439 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 440         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 441                           nlmsg_attrlen(nlh, hdrlen), rem)
 442
 443 /**
 444  * nlmsg_put - Add a new netlink message to an skb
 445  * @skb: socket buffer to store message in
 446  * @portid: netlink PORTID of requesting application
 447  * @seq: sequence number of message
 448  * @type: message type
 449  * @payload: length of message payload
 450  * @flags: message flags
 451  *
 452  * Returns NULL if the tailroom of the skb is insufficient to store
 453  * the message header and payload.
 454  */
 455 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 456                                          int type, int payload, int flags)
 457 {
 458         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 459                 return NULL;
 460
 461         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 462 }
 463
 464 /**
 465  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 466  * @skb: socket buffer to store message in
 467  * @cb: netlink callback
 468  * @type: message type
 469  * @payload: length of message payload
 470  * @flags: message flags
 471  *
 472  * Returns NULL if the tailroom of the skb is insufficient to store
 473  * the message header and payload.
 474  */
 475 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 476                                                 struct netlink_callback *cb,
 477                                                 int type, int payload,
 478                                                 int flags)
 479 {
 480         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 481                          type, payload, flags);
 482 }
 483
 484 /**
 485  * nlmsg_new - Allocate a new netlink message
 486  * @payload: size of the message payload
 487  * @flags: the type of memory to allocate.
 488  *
 489  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 490  * and a good default is needed.
 491  */
 492 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 493 {
 494         return alloc_skb(nlmsg_total_size(payload), flags);
 495 }
 496
 497 /**
 498  * nlmsg_end - Finalize a netlink message
 499  * @skb: socket buffer the message is stored in
 500  * @nlh: netlink message header
 501  *
 502  * Corrects the netlink message header to include the appeneded
 503  * attributes. Only necessary if attributes have been added to
 504  * the message.
 505  */
 506 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 507 {
 508         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 509 }
 510
 511 /**
 512  * nlmsg_get_pos - return current position in netlink message
 513  * @skb: socket buffer the message is stored in
 514  *
 515  * Returns a pointer to the current tail of the message.
 516  */
 517 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 518 {
 519         return skb_tail_pointer(skb);
 520 }
 521
 522 /**
 523  * nlmsg_trim - Trim message to a mark
 524  * @skb: socket buffer the message is stored in
 525  * @mark: mark to trim to
 526  *
 527  * Trims the message to the provided mark.
 528  */
 529 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 530 {
 531         if (mark) {
 532                 WARN_ON((unsigned char *) mark < skb->data);
 533                 skb_trim(skb, (unsigned char *) mark - skb->data);
 534         }
 535 }
 536
 537 /**
 538  * nlmsg_cancel - Cancel construction of a netlink message
 539  * @skb: socket buffer the message is stored in
 540  * @nlh: netlink message header
 541  *
 542  * Removes the complete netlink message including all
 543  * attributes from the socket buffer again.
 544  */
 545 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 546 {
 547         nlmsg_trim(skb, nlh);
 548 }
 549
 550 /**
 551  * nlmsg_free - free a netlink message
 552  * @skb: socket buffer of netlink message
 553  */
 554 static inline void nlmsg_free(struct sk_buff *skb)
 555 {
 556         kfree_skb(skb);
 557 }
 558
 559 /**
 560  * nlmsg_multicast - multicast a netlink message
 561  * @sk: netlink socket to spread messages to
 562  * @skb: netlink message as socket buffer
 563  * @portid: own netlink portid to avoid sending to yourself
 564  * @group: multicast group id
 565  * @flags: allocation flags
 566  */
 567 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 568                                   u32 portid, unsigned int group, gfp_t flags)
 569 {
 570         int err;
 571
 572         NETLINK_CB(skb).dst_group = group;
 573
 574         err = netlink_broadcast(sk, skb, portid, group, flags);
 575         if (err > 0)
 576                 err = 0;
 577
 578         return err;
 579 }
 580
 581 /**
 582  * nlmsg_unicast - unicast a netlink message
 583  * @sk: netlink socket to spread message to
 584  * @skb: netlink message as socket buffer
 585  * @portid: netlink portid of the destination socket
 586  */
 587 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 588 {
 589         int err;
 590
 591         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 592         if (err > 0)
 593                 err = 0;
 594
 595         return err;
 596 }
 597
 598 /**
 599  * nlmsg_for_each_msg - iterate over a stream of messages
 600  * @pos: loop counter, set to current message
 601  * @head: head of message stream
 602  * @len: length of message stream
 603  * @rem: initialized to len, holds bytes currently remaining in stream
 604  */
 605 #define nlmsg_for_each_msg(pos, head, len, rem) \
 606         for (pos = head, rem = len; \
 607              nlmsg_ok(pos, rem); \
 608              pos = nlmsg_next(pos, &(rem)))
 609
 610 /**
 611  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 612  * @cb: netlink callback structure that stores the sequence number
 613  * @nlh: netlink message header to write the flag to
 614  *
 615  * This function checks if the sequence (generation) number changed during dump
 616  * and if it did, advertises it in the netlink message header.
 617  *
 618  * The correct way to use it is to set cb->seq to the generation counter when
 619  * all locks for dumping have been acquired, and then call this function for
 620  * each message that is generated.
 621  *
 622  * Note that due to initialisation concerns, 0 is an invalid sequence number
 623  * and must not be used by code that uses this functionality.
 624  */
 625 static inline void
 626 nl_dump_check_consistent(struct netlink_callback *cb,
 627                          struct nlmsghdr *nlh)
 628 {
 629         if (cb->prev_seq && cb->seq != cb->prev_seq)
 630                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 631         cb->prev_seq = cb->seq;
 632 }
 633
 634 /**************************************************************************
 635  * Netlink Attributes
 636  **************************************************************************/
 637
 638 /**
 639  * nla_attr_size - length of attribute not including padding
 640  * @payload: length of payload
 641  */
 642 static inline int nla_attr_size(int payload)
 643 {
 644         return NLA_HDRLEN + payload;
 645 }
 646
 647 /**
 648  * nla_total_size - total length of attribute including padding
 649  * @payload: length of payload
 650  */
 651 static inline int nla_total_size(int payload)
 652 {
 653         return NLA_ALIGN(nla_attr_size(payload));
 654 }
 655
 656 /**
 657  * nla_padlen - length of padding at the tail of attribute
 658  * @payload: length of payload
 659  */
 660 static inline int nla_padlen(int payload)
 661 {
 662         return nla_total_size(payload) - nla_attr_size(payload);
 663 }
 664
 665 /**
 666  * nla_type - attribute type
 667  * @nla: netlink attribute
 668  */
 669 static inline int nla_type(const struct nlattr *nla)
 670 {
 671         return nla->nla_type & NLA_TYPE_MASK;
 672 }
 673
 674 /**
 675  * nla_data - head of payload
 676  * @nla: netlink attribute
 677  */
 678 static inline void *nla_data(const struct nlattr *nla)
 679 {
 680         return (char *) nla + NLA_HDRLEN;
 681 }
 682
 683 /**
 684  * nla_len - length of payload
 685  * @nla: netlink attribute
 686  */
 687 static inline int nla_len(const struct nlattr *nla)
 688 {
 689         return nla->nla_len - NLA_HDRLEN;
 690 }
 691
 692 /**
 693  * nla_ok - check if the netlink attribute fits into the remaining bytes
 694  * @nla: netlink attribute
 695  * @remaining: number of bytes remaining in attribute stream
 696  */
 697 static inline int nla_ok(const struct nlattr *nla, int remaining)
 698 {
 699         return remaining >= (int) sizeof(*nla) &&
 700                nla->nla_len >= sizeof(*nla) &&
 701                nla->nla_len <= remaining;
 702 }
 703
 704 /**
 705  * nla_next - next netlink attribute in attribute stream
 706  * @nla: netlink attribute
 707  * @remaining: number of bytes remaining in attribute stream
 708  *
 709  * Returns the next netlink attribute in the attribute stream and
 710  * decrements remaining by the size of the current attribute.
 711  */
 712 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 713 {
 714         int totlen = NLA_ALIGN(nla->nla_len);
 715
 716         *remaining -= totlen;
 717         return (struct nlattr *) ((char *) nla + totlen);
 718 }
 719
 720 /**
 721  * nla_find_nested - find attribute in a set of nested attributes
 722  * @nla: attribute containing the nested attributes
 723  * @attrtype: type of attribute to look for
 724  *
 725  * Returns the first attribute which matches the specified type.
 726  */
 727 static inline struct nlattr *
 728 nla_find_nested(const struct nlattr *nla, int attrtype)
 729 {
 730         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 731 }
 732
 733 /**
 734  * nla_parse_nested - parse nested attributes
 735  * @tb: destination array with maxtype+1 elements
 736  * @maxtype: maximum attribute type to be expected
 737  * @nla: attribute containing the nested attributes
 738  * @policy: validation policy
 739  *
 740  * See nla_parse()
 741  */
 742 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 743                                    const struct nlattr *nla,
 744                                    const struct nla_policy *policy)
 745 {
 746         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 747 }
 748
 749 /**
 750  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 751  * @skb: socket buffer to add attribute to
 752  * @attrtype: attribute type
 753  * @value: numeric value
 754  */
 755 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 756 {
 757         return nla_put(skb, attrtype, sizeof(u8), &value);
 758 }
 759
 760 /**
 761  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 762  * @skb: socket buffer to add attribute to
 763  * @attrtype: attribute type
 764  * @value: numeric value
 765  */
 766 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 767 {
 768         return nla_put(skb, attrtype, sizeof(u16), &value);
 769 }
 770
 771 /**
 772  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 773  * @skb: socket buffer to add attribute to
 774  * @attrtype: attribute type
 775  * @value: numeric value
 776  */
 777 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 778 {
 779         return nla_put(skb, attrtype, sizeof(__be16), &value);
 780 }
 781
 782 /**
 783  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 784  * @skb: socket buffer to add attribute to
 785  * @attrtype: attribute type
 786  * @value: numeric value
 787  */
 788 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 789 {
 790         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 791 }
 792
 793 /**
 794  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 795  * @skb: socket buffer to add attribute to
 796  * @attrtype: attribute type
 797  * @value: numeric value
 798  */
 799 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 800 {
 801         return nla_put(skb, attrtype, sizeof(__le16), &value);
 802 }
 803
 804 /**
 805  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 806  * @skb: socket buffer to add attribute to
 807  * @attrtype: attribute type
 808  * @value: numeric value
 809  */
 810 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 811 {
 812         return nla_put(skb, attrtype, sizeof(u32), &value);
 813 }
 814
 815 /**
 816  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 817  * @skb: socket buffer to add attribute to
 818  * @attrtype: attribute type
 819  * @value: numeric value
 820  */
 821 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 822 {
 823         return nla_put(skb, attrtype, sizeof(__be32), &value);
 824 }
 825
 826 /**
 827  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 828  * @skb: socket buffer to add attribute to
 829  * @attrtype: attribute type
 830  * @value: numeric value
 831  */
 832 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 833 {
 834         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 835 }
 836
 837 /**
 838  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 839  * @skb: socket buffer to add attribute to
 840  * @attrtype: attribute type
 841  * @value: numeric value
 842  */
 843 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 844 {
 845         return nla_put(skb, attrtype, sizeof(__le32), &value);
 846 }
 847
 848 /**
 849  * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
 850  * @skb: socket buffer to add attribute to
 851  * @attrtype: attribute type
 852  * @value: numeric value
 853  */
 854 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 855 {
 856         return nla_put(skb, attrtype, sizeof(u64), &value);
 857 }
 858
 859 /**
 860  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 861  * @skb: socket buffer to add attribute to
 862  * @attrtype: attribute type
 863  * @value: numeric value
 864  * @padattr: attribute type for the padding
 865  */
 866 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
 867                                int padattr)
 868 {
 869         return nla_put_64bit(skb, attrtype, sizeof(__be64), &value, padattr);
 870 }
 871
 872 /**
 873  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
 874  * @skb: socket buffer to add attribute to
 875  * @attrtype: attribute type
 876  * @value: numeric value
 877  * @padattr: attribute type for the padding
 878  */
 879 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
 880                                 int padattr)
 881 {
 882         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value,
 883                             padattr);
 884 }
 885
 886 /**
 887  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 888  * @skb: socket buffer to add attribute to
 889  * @attrtype: attribute type
 890  * @value: numeric value
 891  * @padattr: attribute type for the padding
 892  */
 893 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
 894                                int padattr)
 895 {
 896         return nla_put_64bit(skb, attrtype, sizeof(__le64), &value, padattr);
 897 }
 898
 899 /**
 900  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 901  * @skb: socket buffer to add attribute to
 902  * @attrtype: attribute type
 903  * @value: numeric value
 904  */
 905 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 906 {
 907         return nla_put(skb, attrtype, sizeof(s8), &value);
 908 }
 909
 910 /**
 911  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 912  * @skb: socket buffer to add attribute to
 913  * @attrtype: attribute type
 914  * @value: numeric value
 915  */
 916 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 917 {
 918         return nla_put(skb, attrtype, sizeof(s16), &value);
 919 }
 920
 921 /**
 922  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 923  * @skb: socket buffer to add attribute to
 924  * @attrtype: attribute type
 925  * @value: numeric value
 926  */
 927 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 928 {
 929         return nla_put(skb, attrtype, sizeof(s32), &value);
 930 }
 931
 932 /**
 933  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 934  * @skb: socket buffer to add attribute to
 935  * @attrtype: attribute type
 936  * @value: numeric value
 937  * @padattr: attribute type for the padding
 938  */
 939 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
 940                               int padattr)
 941 {
 942         return nla_put_64bit(skb, attrtype, sizeof(s64), &value, padattr);
 943 }
 944
 945 /**
 946  * nla_put_string - Add a string netlink attribute to a socket buffer
 947  * @skb: socket buffer to add attribute to
 948  * @attrtype: attribute type
 949  * @str: NUL terminated string
 950  */
 951 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 952                                  const char *str)
 953 {
 954         return nla_put(skb, attrtype, strlen(str) + 1, str);
 955 }
 956
 957 /**
 958  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 959  * @skb: socket buffer to add attribute to
 960  * @attrtype: attribute type
 961  */
 962 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 963 {
 964         return nla_put(skb, attrtype, 0, NULL);
 965 }
 966
 967 /**
 968  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 969  * @skb: socket buffer to add attribute to
 970  * @attrtype: attribute type
 971  * @njiffies: number of jiffies to convert to msecs
 972  */
 973 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 974                                 unsigned long njiffies)
 975 {
 976         u64 tmp = jiffies_to_msecs(njiffies);
 977         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 978 }
 979
 980 /**
 981  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 982  * buffer
 983  * @skb: socket buffer to add attribute to
 984  * @attrtype: attribute type
 985  * @addr: IPv4 address
 986  */
 987 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
 988                                   __be32 addr)
 989 {
 990         return nla_put_be32(skb, attrtype, addr);
 991 }
 992
 993 /**
 994  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
 995  * buffer
 996  * @skb: socket buffer to add attribute to
 997  * @attrtype: attribute type
 998  * @addr: IPv6 address
 999  */
1000 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1001                                    const struct in6_addr *addr)
1002 {
1003         return nla_put(skb, attrtype, sizeof(*addr), addr);
1004 }
1005
1006 /**
1007  * nla_get_u32 - return payload of u32 attribute
1008  * @nla: u32 netlink attribute
1009  */
1010 static inline u32 nla_get_u32(const struct nlattr *nla)
1011 {
1012         return *(u32 *) nla_data(nla);
1013 }
1014
1015 /**
1016  * nla_get_be32 - return payload of __be32 attribute
1017  * @nla: __be32 netlink attribute
1018  */
1019 static inline __be32 nla_get_be32(const struct nlattr *nla)
1020 {
1021         return *(__be32 *) nla_data(nla);
1022 }
1023
1024 /**
1025  * nla_get_le32 - return payload of __le32 attribute
1026  * @nla: __le32 netlink attribute
1027  */
1028 static inline __le32 nla_get_le32(const struct nlattr *nla)
1029 {
1030         return *(__le32 *) nla_data(nla);
1031 }
1032
1033 /**
1034  * nla_get_u16 - return payload of u16 attribute
1035  * @nla: u16 netlink attribute
1036  */
1037 static inline u16 nla_get_u16(const struct nlattr *nla)
1038 {
1039         return *(u16 *) nla_data(nla);
1040 }
1041
1042 /**
1043  * nla_get_be16 - return payload of __be16 attribute
1044  * @nla: __be16 netlink attribute
1045  */
1046 static inline __be16 nla_get_be16(const struct nlattr *nla)
1047 {
1048         return *(__be16 *) nla_data(nla);
1049 }
1050
1051 /**
1052  * nla_get_le16 - return payload of __le16 attribute
1053  * @nla: __le16 netlink attribute
1054  */
1055 static inline __le16 nla_get_le16(const struct nlattr *nla)
1056 {
1057         return *(__le16 *) nla_data(nla);
1058 }
1059
1060 /**
1061  * nla_get_u8 - return payload of u8 attribute
1062  * @nla: u8 netlink attribute
1063  */
1064 static inline u8 nla_get_u8(const struct nlattr *nla)
1065 {
1066         return *(u8 *) nla_data(nla);
1067 }
1068
1069 /**
1070  * nla_get_u64 - return payload of u64 attribute
1071  * @nla: u64 netlink attribute
1072  */
1073 static inline u64 nla_get_u64(const struct nlattr *nla)
1074 {
1075         u64 tmp;
1076
1077         nla_memcpy(&tmp, nla, sizeof(tmp));
1078
1079         return tmp;
1080 }
1081
1082 /**
1083  * nla_get_be64 - return payload of __be64 attribute
1084  * @nla: __be64 netlink attribute
1085  */
1086 static inline __be64 nla_get_be64(const struct nlattr *nla)
1087 {
1088         __be64 tmp;
1089
1090         nla_memcpy(&tmp, nla, sizeof(tmp));
1091
1092         return tmp;
1093 }
1094
1095 /**
1096  * nla_get_le64 - return payload of __le64 attribute
1097  * @nla: __le64 netlink attribute
1098  */
1099 static inline __le64 nla_get_le64(const struct nlattr *nla)
1100 {
1101         return *(__le64 *) nla_data(nla);
1102 }
1103
1104 /**
1105  * nla_get_s32 - return payload of s32 attribute
1106  * @nla: s32 netlink attribute
1107  */
1108 static inline s32 nla_get_s32(const struct nlattr *nla)
1109 {
1110         return *(s32 *) nla_data(nla);
1111 }
1112
1113 /**
1114  * nla_get_s16 - return payload of s16 attribute
1115  * @nla: s16 netlink attribute
1116  */
1117 static inline s16 nla_get_s16(const struct nlattr *nla)
1118 {
1119         return *(s16 *) nla_data(nla);
1120 }
1121
1122 /**
1123  * nla_get_s8 - return payload of s8 attribute
1124  * @nla: s8 netlink attribute
1125  */
1126 static inline s8 nla_get_s8(const struct nlattr *nla)
1127 {
1128         return *(s8 *) nla_data(nla);
1129 }
1130
1131 /**
1132  * nla_get_s64 - return payload of s64 attribute
1133  * @nla: s64 netlink attribute
1134  */
1135 static inline s64 nla_get_s64(const struct nlattr *nla)
1136 {
1137         s64 tmp;
1138
1139         nla_memcpy(&tmp, nla, sizeof(tmp));
1140
1141         return tmp;
1142 }
1143
1144 /**
1145  * nla_get_flag - return payload of flag attribute
1146  * @nla: flag netlink attribute
1147  */
1148 static inline int nla_get_flag(const struct nlattr *nla)
1149 {
1150         return !!nla;
1151 }
1152
1153 /**
1154  * nla_get_msecs - return payload of msecs attribute
1155  * @nla: msecs netlink attribute
1156  *
1157  * Returns the number of milliseconds in jiffies.
1158  */
1159 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1160 {
1161         u64 msecs = nla_get_u64(nla);
1162
1163         return msecs_to_jiffies((unsigned long) msecs);
1164 }
1165
1166 /**
1167  * nla_get_in_addr - return payload of IPv4 address attribute
1168  * @nla: IPv4 address netlink attribute
1169  */
1170 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1171 {
1172         return *(__be32 *) nla_data(nla);
1173 }
1174
1175 /**
1176  * nla_get_in6_addr - return payload of IPv6 address attribute
1177  * @nla: IPv6 address netlink attribute
1178  */
1179 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1180 {
1181         struct in6_addr tmp;
1182
1183         nla_memcpy(&tmp, nla, sizeof(tmp));
1184         return tmp;
1185 }
1186
1187 /**
1188  * nla_nest_start - Start a new level of nested attributes
1189  * @skb: socket buffer to add attributes to
1190  * @attrtype: attribute type of container
1191  *
1192  * Returns the container attribute
1193  */
1194 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1195 {
1196         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1197
1198         if (nla_put(skb, attrtype, 0, NULL) < 0)
1199                 return NULL;
1200
1201         return start;
1202 }
1203
1204 /**
1205  * nla_nest_end - Finalize nesting of attributes
1206  * @skb: socket buffer the attributes are stored in
1207  * @start: container attribute
1208  *
1209  * Corrects the container attribute header to include the all
1210  * appeneded attributes.
1211  *
1212  * Returns the total data length of the skb.
1213  */
1214 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1215 {
1216         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1217         return skb->len;
1218 }
1219
1220 /**
1221  * nla_nest_cancel - Cancel nesting of attributes
1222  * @skb: socket buffer the message is stored in
1223  * @start: container attribute
1224  *
1225  * Removes the container attribute and including all nested
1226  * attributes. Returns -EMSGSIZE
1227  */
1228 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1229 {
1230         nlmsg_trim(skb, start);
1231 }
1232
1233 /**
1234  * nla_validate_nested - Validate a stream of nested attributes
1235  * @start: container attribute
1236  * @maxtype: maximum attribute type to be expected
1237  * @policy: validation policy
1238  *
1239  * Validates all attributes in the nested attribute stream against the
1240  * specified policy. Attributes with a type exceeding maxtype will be
1241  * ignored. See documenation of struct nla_policy for more details.
1242  *
1243  * Returns 0 on success or a negative error code.
1244  */
1245 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1246                                       const struct nla_policy *policy)
1247 {
1248         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1249 }
1250
1251 /**
1252  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1253  * @skb: socket buffer the message is stored in
1254  *
1255  * Return true if padding is needed to align the next attribute (nla_data()) to
1256  * a 64-bit aligned area.
1257  */
1258 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1259 {
1260 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1261         /* The nlattr header is 4 bytes in size, that's why we test
1262          * if the skb->data _is_ aligned.  A NOP attribute, plus
1263          * nlattr header for next attribute, will make nla_data()
1264          * 8-byte aligned.
1265          */
1266         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1267                 return true;
1268 #endif
1269         return false;
1270 }
1271
1272 /**
1273  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1274  * @skb: socket buffer the message is stored in
1275  * @padattr: attribute type for the padding
1276  *
1277  * Conditionally emit a padding netlink attribute in order to make
1278  * the next attribute we emit have a 64-bit aligned nla_data() area.
1279  * This will only be done in architectures which do not have
1280  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1281  *
1282  * Returns zero on success or a negative error code.
1283  */
1284 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1285 {
1286         if (nla_need_padding_for_64bit(skb) &&
1287             !nla_reserve(skb, padattr, 0))
1288                 return -EMSGSIZE;
1289
1290         return 0;
1291 }
1292
1293 /**
1294  * nla_total_size_64bit - total length of attribute including padding
1295  * @payload: length of payload
1296  */
1297 static inline int nla_total_size_64bit(int payload)
1298 {
1299         return NLA_ALIGN(nla_attr_size(payload))
1300 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1301                 + NLA_ALIGN(nla_attr_size(0))
1302 #endif
1303                 ;
1304 }
1305
1306 /**
1307  * nla_for_each_attr - iterate over a stream of attributes
1308  * @pos: loop counter, set to current attribute
1309  * @head: head of attribute stream
1310  * @len: length of attribute stream
1311  * @rem: initialized to len, holds bytes currently remaining in stream
1312  */
1313 #define nla_for_each_attr(pos, head, len, rem) \
1314         for (pos = head, rem = len; \
1315              nla_ok(pos, rem); \
1316              pos = nla_next(pos, &(rem)))
1317
1318 /**
1319  * nla_for_each_nested - iterate over nested attributes
1320  * @pos: loop counter, set to current attribute
1321  * @nla: attribute containing the nested attributes
1322  * @rem: initialized to len, holds bytes currently remaining in stream
1323  */
1324 #define nla_for_each_nested(pos, nla, rem) \
1325         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1326
1327 /**
1328  * nla_is_last - Test if attribute is last in stream
1329  * @nla: attribute to test
1330  * @rem: bytes remaining in stream
1331  */
1332 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1333 {
1334         return nla->nla_len == rem;
1335 }
1336
1337 #endif