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 };
 233
 234 int netlink_rcv_skb(struct sk_buff *skb,
 235                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
 236 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 237                  unsigned int group, int report, gfp_t flags);
 238
 239 int nla_validate(const struct nlattr *head, int len, int maxtype,
 240                  const struct nla_policy *policy);
 241 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 242               int len, const struct nla_policy *policy);
 243 int nla_policy_len(const struct nla_policy *, int);
 244 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 245 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 246 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 247 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 248 int nla_strcmp(const struct nlattr *nla, const char *str);
 249 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 250 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 251                                    int attrlen, int padattr);
 252 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 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 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 258                const void *data);
 259 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 260                      const void *data, int padattr);
 261 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 262 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 263 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 264                   const void *data, int padattr);
 265 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 266 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 267
 268 /**************************************************************************
 269  * Netlink Messages
 270  **************************************************************************/
 271
 272 /**
 273  * nlmsg_msg_size - length of netlink message not including padding
 274  * @payload: length of message payload
 275  */
 276 static inline int nlmsg_msg_size(int payload)
 277 {
 278         return NLMSG_HDRLEN + payload;
 279 }
 280
 281 /**
 282  * nlmsg_total_size - length of netlink message including padding
 283  * @payload: length of message payload
 284  */
 285 static inline int nlmsg_total_size(int payload)
 286 {
 287         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 288 }
 289
 290 /**
 291  * nlmsg_padlen - length of padding at the message's tail
 292  * @payload: length of message payload
 293  */
 294 static inline int nlmsg_padlen(int payload)
 295 {
 296         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 297 }
 298
 299 /**
 300  * nlmsg_data - head of message payload
 301  * @nlh: netlink message header
 302  */
 303 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 304 {
 305         return (unsigned char *) nlh + NLMSG_HDRLEN;
 306 }
 307
 308 /**
 309  * nlmsg_len - length of message payload
 310  * @nlh: netlink message header
 311  */
 312 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 313 {
 314         return nlh->nlmsg_len - NLMSG_HDRLEN;
 315 }
 316
 317 /**
 318  * nlmsg_attrdata - head of attributes data
 319  * @nlh: netlink message header
 320  * @hdrlen: length of family specific header
 321  */
 322 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 323                                             int hdrlen)
 324 {
 325         unsigned char *data = nlmsg_data(nlh);
 326         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 327 }
 328
 329 /**
 330  * nlmsg_attrlen - length of attributes data
 331  * @nlh: netlink message header
 332  * @hdrlen: length of family specific header
 333  */
 334 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 335 {
 336         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 337 }
 338
 339 /**
 340  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 341  * @nlh: netlink message header
 342  * @remaining: number of bytes remaining in message stream
 343  */
 344 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 345 {
 346         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 347                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 348                 nlh->nlmsg_len <= remaining);
 349 }
 350
 351 /**
 352  * nlmsg_next - next netlink message in message stream
 353  * @nlh: netlink message header
 354  * @remaining: number of bytes remaining in message stream
 355  *
 356  * Returns the next netlink message in the message stream and
 357  * decrements remaining by the size of the current message.
 358  */
 359 static inline struct nlmsghdr *
 360 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 361 {
 362         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 363
 364         *remaining -= totlen;
 365
 366         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 367 }
 368
 369 /**
 370  * nlmsg_parse - parse attributes of a netlink message
 371  * @nlh: netlink message header
 372  * @hdrlen: length of family specific header
 373  * @tb: destination array with maxtype+1 elements
 374  * @maxtype: maximum attribute type to be expected
 375  * @policy: validation policy
 376  *
 377  * See nla_parse()
 378  */
 379 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 380                               struct nlattr *tb[], int maxtype,
 381                               const struct nla_policy *policy)
 382 {
 383         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 384                 return -EINVAL;
 385
 386         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 387                          nlmsg_attrlen(nlh, hdrlen), policy);
 388 }
 389
 390 /**
 391  * nlmsg_find_attr - find a specific attribute in a netlink message
 392  * @nlh: netlink message header
 393  * @hdrlen: length of familiy specific header
 394  * @attrtype: type of attribute to look for
 395  *
 396  * Returns the first attribute which matches the specified type.
 397  */
 398 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 399                                              int hdrlen, int attrtype)
 400 {
 401         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 402                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 403 }
 404
 405 /**
 406  * nlmsg_validate - validate a netlink message including attributes
 407  * @nlh: netlinket message header
 408  * @hdrlen: length of familiy specific header
 409  * @maxtype: maximum attribute type to be expected
 410  * @policy: validation policy
 411  */
 412 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 413                                  int hdrlen, int maxtype,
 414                                  const struct nla_policy *policy)
 415 {
 416         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 417                 return -EINVAL;
 418
 419         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 420                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 421 }
 422
 423 /**
 424  * nlmsg_report - need to report back to application?
 425  * @nlh: netlink message header
 426  *
 427  * Returns 1 if a report back to the application is requested.
 428  */
 429 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 430 {
 431         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 432 }
 433
 434 /**
 435  * nlmsg_for_each_attr - iterate over a stream of attributes
 436  * @pos: loop counter, set to current attribute
 437  * @nlh: netlink message header
 438  * @hdrlen: length of familiy specific header
 439  * @rem: initialized to len, holds bytes currently remaining in stream
 440  */
 441 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 442         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 443                           nlmsg_attrlen(nlh, hdrlen), rem)
 444
 445 /**
 446  * nlmsg_put - Add a new netlink message to an skb
 447  * @skb: socket buffer to store message in
 448  * @portid: netlink PORTID of requesting application
 449  * @seq: sequence number of message
 450  * @type: message type
 451  * @payload: length of message payload
 452  * @flags: message flags
 453  *
 454  * Returns NULL if the tailroom of the skb is insufficient to store
 455  * the message header and payload.
 456  */
 457 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 458                                          int type, int payload, int flags)
 459 {
 460         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 461                 return NULL;
 462
 463         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 464 }
 465
 466 /**
 467  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 468  * @skb: socket buffer to store message in
 469  * @cb: netlink callback
 470  * @type: message type
 471  * @payload: length of message payload
 472  * @flags: message flags
 473  *
 474  * Returns NULL if the tailroom of the skb is insufficient to store
 475  * the message header and payload.
 476  */
 477 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 478                                                 struct netlink_callback *cb,
 479                                                 int type, int payload,
 480                                                 int flags)
 481 {
 482         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 483                          type, payload, flags);
 484 }
 485
 486 /**
 487  * nlmsg_new - Allocate a new netlink message
 488  * @payload: size of the message payload
 489  * @flags: the type of memory to allocate.
 490  *
 491  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 492  * and a good default is needed.
 493  */
 494 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 495 {
 496         return alloc_skb(nlmsg_total_size(payload), flags);
 497 }
 498
 499 /**
 500  * nlmsg_end - Finalize a netlink message
 501  * @skb: socket buffer the message is stored in
 502  * @nlh: netlink message header
 503  *
 504  * Corrects the netlink message header to include the appeneded
 505  * attributes. Only necessary if attributes have been added to
 506  * the message.
 507  */
 508 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 509 {
 510         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 511 }
 512
 513 /**
 514  * nlmsg_get_pos - return current position in netlink message
 515  * @skb: socket buffer the message is stored in
 516  *
 517  * Returns a pointer to the current tail of the message.
 518  */
 519 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 520 {
 521         return skb_tail_pointer(skb);
 522 }
 523
 524 /**
 525  * nlmsg_trim - Trim message to a mark
 526  * @skb: socket buffer the message is stored in
 527  * @mark: mark to trim to
 528  *
 529  * Trims the message to the provided mark.
 530  */
 531 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 532 {
 533         if (mark) {
 534                 WARN_ON((unsigned char *) mark < skb->data);
 535                 skb_trim(skb, (unsigned char *) mark - skb->data);
 536         }
 537 }
 538
 539 /**
 540  * nlmsg_cancel - Cancel construction of a netlink message
 541  * @skb: socket buffer the message is stored in
 542  * @nlh: netlink message header
 543  *
 544  * Removes the complete netlink message including all
 545  * attributes from the socket buffer again.
 546  */
 547 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 548 {
 549         nlmsg_trim(skb, nlh);
 550 }
 551
 552 /**
 553  * nlmsg_free - free a netlink message
 554  * @skb: socket buffer of netlink message
 555  */
 556 static inline void nlmsg_free(struct sk_buff *skb)
 557 {
 558         kfree_skb(skb);
 559 }
 560
 561 /**
 562  * nlmsg_multicast - multicast a netlink message
 563  * @sk: netlink socket to spread messages to
 564  * @skb: netlink message as socket buffer
 565  * @portid: own netlink portid to avoid sending to yourself
 566  * @group: multicast group id
 567  * @flags: allocation flags
 568  */
 569 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 570                                   u32 portid, unsigned int group, gfp_t flags)
 571 {
 572         int err;
 573
 574         NETLINK_CB(skb).dst_group = group;
 575
 576         err = netlink_broadcast(sk, skb, portid, group, flags);
 577         if (err > 0)
 578                 err = 0;
 579
 580         return err;
 581 }
 582
 583 /**
 584  * nlmsg_unicast - unicast a netlink message
 585  * @sk: netlink socket to spread message to
 586  * @skb: netlink message as socket buffer
 587  * @portid: netlink portid of the destination socket
 588  */
 589 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 590 {
 591         int err;
 592
 593         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 594         if (err > 0)
 595                 err = 0;
 596
 597         return err;
 598 }
 599
 600 /**
 601  * nlmsg_for_each_msg - iterate over a stream of messages
 602  * @pos: loop counter, set to current message
 603  * @head: head of message stream
 604  * @len: length of message stream
 605  * @rem: initialized to len, holds bytes currently remaining in stream
 606  */
 607 #define nlmsg_for_each_msg(pos, head, len, rem) \
 608         for (pos = head, rem = len; \
 609              nlmsg_ok(pos, rem); \
 610              pos = nlmsg_next(pos, &(rem)))
 611
 612 /**
 613  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 614  * @cb: netlink callback structure that stores the sequence number
 615  * @nlh: netlink message header to write the flag to
 616  *
 617  * This function checks if the sequence (generation) number changed during dump
 618  * and if it did, advertises it in the netlink message header.
 619  *
 620  * The correct way to use it is to set cb->seq to the generation counter when
 621  * all locks for dumping have been acquired, and then call this function for
 622  * each message that is generated.
 623  *
 624  * Note that due to initialisation concerns, 0 is an invalid sequence number
 625  * and must not be used by code that uses this functionality.
 626  */
 627 static inline void
 628 nl_dump_check_consistent(struct netlink_callback *cb,
 629                          struct nlmsghdr *nlh)
 630 {
 631         if (cb->prev_seq && cb->seq != cb->prev_seq)
 632                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 633         cb->prev_seq = cb->seq;
 634 }
 635
 636 /**************************************************************************
 637  * Netlink Attributes
 638  **************************************************************************/
 639
 640 /**
 641  * nla_attr_size - length of attribute not including padding
 642  * @payload: length of payload
 643  */
 644 static inline int nla_attr_size(int payload)
 645 {
 646         return NLA_HDRLEN + payload;
 647 }
 648
 649 /**
 650  * nla_total_size - total length of attribute including padding
 651  * @payload: length of payload
 652  */
 653 static inline int nla_total_size(int payload)
 654 {
 655         return NLA_ALIGN(nla_attr_size(payload));
 656 }
 657
 658 /**
 659  * nla_padlen - length of padding at the tail of attribute
 660  * @payload: length of payload
 661  */
 662 static inline int nla_padlen(int payload)
 663 {
 664         return nla_total_size(payload) - nla_attr_size(payload);
 665 }
 666
 667 /**
 668  * nla_type - attribute type
 669  * @nla: netlink attribute
 670  */
 671 static inline int nla_type(const struct nlattr *nla)
 672 {
 673         return nla->nla_type & NLA_TYPE_MASK;
 674 }
 675
 676 /**
 677  * nla_data - head of payload
 678  * @nla: netlink attribute
 679  */
 680 static inline void *nla_data(const struct nlattr *nla)
 681 {
 682         return (char *) nla + NLA_HDRLEN;
 683 }
 684
 685 /**
 686  * nla_len - length of payload
 687  * @nla: netlink attribute
 688  */
 689 static inline int nla_len(const struct nlattr *nla)
 690 {
 691         return nla->nla_len - NLA_HDRLEN;
 692 }
 693
 694 /**
 695  * nla_ok - check if the netlink attribute fits into the remaining bytes
 696  * @nla: netlink attribute
 697  * @remaining: number of bytes remaining in attribute stream
 698  */
 699 static inline int nla_ok(const struct nlattr *nla, int remaining)
 700 {
 701         return remaining >= (int) sizeof(*nla) &&
 702                nla->nla_len >= sizeof(*nla) &&
 703                nla->nla_len <= remaining;
 704 }
 705
 706 /**
 707  * nla_next - next netlink attribute in attribute stream
 708  * @nla: netlink attribute
 709  * @remaining: number of bytes remaining in attribute stream
 710  *
 711  * Returns the next netlink attribute in the attribute stream and
 712  * decrements remaining by the size of the current attribute.
 713  */
 714 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 715 {
 716         int totlen = NLA_ALIGN(nla->nla_len);
 717
 718         *remaining -= totlen;
 719         return (struct nlattr *) ((char *) nla + totlen);
 720 }
 721
 722 /**
 723  * nla_find_nested - find attribute in a set of nested attributes
 724  * @nla: attribute containing the nested attributes
 725  * @attrtype: type of attribute to look for
 726  *
 727  * Returns the first attribute which matches the specified type.
 728  */
 729 static inline struct nlattr *
 730 nla_find_nested(const struct nlattr *nla, int attrtype)
 731 {
 732         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 733 }
 734
 735 /**
 736  * nla_parse_nested - parse nested attributes
 737  * @tb: destination array with maxtype+1 elements
 738  * @maxtype: maximum attribute type to be expected
 739  * @nla: attribute containing the nested attributes
 740  * @policy: validation policy
 741  *
 742  * See nla_parse()
 743  */
 744 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 745                                    const struct nlattr *nla,
 746                                    const struct nla_policy *policy)
 747 {
 748         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 749 }
 750
 751 /**
 752  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 753  * @skb: socket buffer to add attribute to
 754  * @attrtype: attribute type
 755  * @value: numeric value
 756  */
 757 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 758 {
 759         return nla_put(skb, attrtype, sizeof(u8), &value);
 760 }
 761
 762 /**
 763  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 764  * @skb: socket buffer to add attribute to
 765  * @attrtype: attribute type
 766  * @value: numeric value
 767  */
 768 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 769 {
 770         return nla_put(skb, attrtype, sizeof(u16), &value);
 771 }
 772
 773 /**
 774  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 775  * @skb: socket buffer to add attribute to
 776  * @attrtype: attribute type
 777  * @value: numeric value
 778  */
 779 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 780 {
 781         return nla_put(skb, attrtype, sizeof(__be16), &value);
 782 }
 783
 784 /**
 785  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 786  * @skb: socket buffer to add attribute to
 787  * @attrtype: attribute type
 788  * @value: numeric value
 789  */
 790 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 791 {
 792         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 793 }
 794
 795 /**
 796  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 797  * @skb: socket buffer to add attribute to
 798  * @attrtype: attribute type
 799  * @value: numeric value
 800  */
 801 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 802 {
 803         return nla_put(skb, attrtype, sizeof(__le16), &value);
 804 }
 805
 806 /**
 807  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 808  * @skb: socket buffer to add attribute to
 809  * @attrtype: attribute type
 810  * @value: numeric value
 811  */
 812 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 813 {
 814         return nla_put(skb, attrtype, sizeof(u32), &value);
 815 }
 816
 817 /**
 818  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 819  * @skb: socket buffer to add attribute to
 820  * @attrtype: attribute type
 821  * @value: numeric value
 822  */
 823 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 824 {
 825         return nla_put(skb, attrtype, sizeof(__be32), &value);
 826 }
 827
 828 /**
 829  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 830  * @skb: socket buffer to add attribute to
 831  * @attrtype: attribute type
 832  * @value: numeric value
 833  */
 834 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 835 {
 836         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 837 }
 838
 839 /**
 840  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 841  * @skb: socket buffer to add attribute to
 842  * @attrtype: attribute type
 843  * @value: numeric value
 844  */
 845 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 846 {
 847         return nla_put(skb, attrtype, sizeof(__le32), &value);
 848 }
 849
 850 /**
 851  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
 852  * @skb: socket buffer to add attribute to
 853  * @attrtype: attribute type
 854  * @value: numeric value
 855  * @padattr: attribute type for the padding
 856  */
 857 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
 858                                     u64 value, int padattr)
 859 {
 860         return nla_put_64bit(skb, attrtype, sizeof(u64), &value, padattr);
 861 }
 862
 863 /**
 864  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 865  * @skb: socket buffer to add attribute to
 866  * @attrtype: attribute type
 867  * @value: numeric value
 868  * @padattr: attribute type for the padding
 869  */
 870 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
 871                                int padattr)
 872 {
 873         return nla_put_64bit(skb, attrtype, sizeof(__be64), &value, padattr);
 874 }
 875
 876 /**
 877  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
 878  * @skb: socket buffer to add attribute to
 879  * @attrtype: attribute type
 880  * @value: numeric value
 881  * @padattr: attribute type for the padding
 882  */
 883 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
 884                                 int padattr)
 885 {
 886         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value,
 887                             padattr);
 888 }
 889
 890 /**
 891  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 892  * @skb: socket buffer to add attribute to
 893  * @attrtype: attribute type
 894  * @value: numeric value
 895  * @padattr: attribute type for the padding
 896  */
 897 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
 898                                int padattr)
 899 {
 900         return nla_put_64bit(skb, attrtype, sizeof(__le64), &value, padattr);
 901 }
 902
 903 /**
 904  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 905  * @skb: socket buffer to add attribute to
 906  * @attrtype: attribute type
 907  * @value: numeric value
 908  */
 909 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 910 {
 911         return nla_put(skb, attrtype, sizeof(s8), &value);
 912 }
 913
 914 /**
 915  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 916  * @skb: socket buffer to add attribute to
 917  * @attrtype: attribute type
 918  * @value: numeric value
 919  */
 920 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 921 {
 922         return nla_put(skb, attrtype, sizeof(s16), &value);
 923 }
 924
 925 /**
 926  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 927  * @skb: socket buffer to add attribute to
 928  * @attrtype: attribute type
 929  * @value: numeric value
 930  */
 931 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 932 {
 933         return nla_put(skb, attrtype, sizeof(s32), &value);
 934 }
 935
 936 /**
 937  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 938  * @skb: socket buffer to add attribute to
 939  * @attrtype: attribute type
 940  * @value: numeric value
 941  * @padattr: attribute type for the padding
 942  */
 943 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
 944                               int padattr)
 945 {
 946         return nla_put_64bit(skb, attrtype, sizeof(s64), &value, padattr);
 947 }
 948
 949 /**
 950  * nla_put_string - Add a string netlink attribute to a socket buffer
 951  * @skb: socket buffer to add attribute to
 952  * @attrtype: attribute type
 953  * @str: NUL terminated string
 954  */
 955 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 956                                  const char *str)
 957 {
 958         return nla_put(skb, attrtype, strlen(str) + 1, str);
 959 }
 960
 961 /**
 962  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 963  * @skb: socket buffer to add attribute to
 964  * @attrtype: attribute type
 965  */
 966 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 967 {
 968         return nla_put(skb, attrtype, 0, NULL);
 969 }
 970
 971 /**
 972  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
 973  * @skb: socket buffer to add attribute to
 974  * @attrtype: attribute type
 975  * @njiffies: number of jiffies to convert to msecs
 976  * @padattr: attribute type for the padding
 977  */
 978 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 979                                 unsigned long njiffies, int padattr)
 980 {
 981         u64 tmp = jiffies_to_msecs(njiffies);
 982
 983         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
 984 }
 985
 986 /**
 987  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 988  * buffer
 989  * @skb: socket buffer to add attribute to
 990  * @attrtype: attribute type
 991  * @addr: IPv4 address
 992  */
 993 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
 994                                   __be32 addr)
 995 {
 996         return nla_put_be32(skb, attrtype, addr);
 997 }
 998
 999 /**
1000  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1001  * buffer
1002  * @skb: socket buffer to add attribute to
1003  * @attrtype: attribute type
1004  * @addr: IPv6 address
1005  */
1006 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1007                                    const struct in6_addr *addr)
1008 {
1009         return nla_put(skb, attrtype, sizeof(*addr), addr);
1010 }
1011
1012 /**
1013  * nla_get_u32 - return payload of u32 attribute
1014  * @nla: u32 netlink attribute
1015  */
1016 static inline u32 nla_get_u32(const struct nlattr *nla)
1017 {
1018         return *(u32 *) nla_data(nla);
1019 }
1020
1021 /**
1022  * nla_get_be32 - return payload of __be32 attribute
1023  * @nla: __be32 netlink attribute
1024  */
1025 static inline __be32 nla_get_be32(const struct nlattr *nla)
1026 {
1027         return *(__be32 *) nla_data(nla);
1028 }
1029
1030 /**
1031  * nla_get_le32 - return payload of __le32 attribute
1032  * @nla: __le32 netlink attribute
1033  */
1034 static inline __le32 nla_get_le32(const struct nlattr *nla)
1035 {
1036         return *(__le32 *) nla_data(nla);
1037 }
1038
1039 /**
1040  * nla_get_u16 - return payload of u16 attribute
1041  * @nla: u16 netlink attribute
1042  */
1043 static inline u16 nla_get_u16(const struct nlattr *nla)
1044 {
1045         return *(u16 *) nla_data(nla);
1046 }
1047
1048 /**
1049  * nla_get_be16 - return payload of __be16 attribute
1050  * @nla: __be16 netlink attribute
1051  */
1052 static inline __be16 nla_get_be16(const struct nlattr *nla)
1053 {
1054         return *(__be16 *) nla_data(nla);
1055 }
1056
1057 /**
1058  * nla_get_le16 - return payload of __le16 attribute
1059  * @nla: __le16 netlink attribute
1060  */
1061 static inline __le16 nla_get_le16(const struct nlattr *nla)
1062 {
1063         return *(__le16 *) nla_data(nla);
1064 }
1065
1066 /**
1067  * nla_get_u8 - return payload of u8 attribute
1068  * @nla: u8 netlink attribute
1069  */
1070 static inline u8 nla_get_u8(const struct nlattr *nla)
1071 {
1072         return *(u8 *) nla_data(nla);
1073 }
1074
1075 /**
1076  * nla_get_u64 - return payload of u64 attribute
1077  * @nla: u64 netlink attribute
1078  */
1079 static inline u64 nla_get_u64(const struct nlattr *nla)
1080 {
1081         u64 tmp;
1082
1083         nla_memcpy(&tmp, nla, sizeof(tmp));
1084
1085         return tmp;
1086 }
1087
1088 /**
1089  * nla_get_be64 - return payload of __be64 attribute
1090  * @nla: __be64 netlink attribute
1091  */
1092 static inline __be64 nla_get_be64(const struct nlattr *nla)
1093 {
1094         __be64 tmp;
1095
1096         nla_memcpy(&tmp, nla, sizeof(tmp));
1097
1098         return tmp;
1099 }
1100
1101 /**
1102  * nla_get_le64 - return payload of __le64 attribute
1103  * @nla: __le64 netlink attribute
1104  */
1105 static inline __le64 nla_get_le64(const struct nlattr *nla)
1106 {
1107         return *(__le64 *) nla_data(nla);
1108 }
1109
1110 /**
1111  * nla_get_s32 - return payload of s32 attribute
1112  * @nla: s32 netlink attribute
1113  */
1114 static inline s32 nla_get_s32(const struct nlattr *nla)
1115 {
1116         return *(s32 *) nla_data(nla);
1117 }
1118
1119 /**
1120  * nla_get_s16 - return payload of s16 attribute
1121  * @nla: s16 netlink attribute
1122  */
1123 static inline s16 nla_get_s16(const struct nlattr *nla)
1124 {
1125         return *(s16 *) nla_data(nla);
1126 }
1127
1128 /**
1129  * nla_get_s8 - return payload of s8 attribute
1130  * @nla: s8 netlink attribute
1131  */
1132 static inline s8 nla_get_s8(const struct nlattr *nla)
1133 {
1134         return *(s8 *) nla_data(nla);
1135 }
1136
1137 /**
1138  * nla_get_s64 - return payload of s64 attribute
1139  * @nla: s64 netlink attribute
1140  */
1141 static inline s64 nla_get_s64(const struct nlattr *nla)
1142 {
1143         s64 tmp;
1144
1145         nla_memcpy(&tmp, nla, sizeof(tmp));
1146
1147         return tmp;
1148 }
1149
1150 /**
1151  * nla_get_flag - return payload of flag attribute
1152  * @nla: flag netlink attribute
1153  */
1154 static inline int nla_get_flag(const struct nlattr *nla)
1155 {
1156         return !!nla;
1157 }
1158
1159 /**
1160  * nla_get_msecs - return payload of msecs attribute
1161  * @nla: msecs netlink attribute
1162  *
1163  * Returns the number of milliseconds in jiffies.
1164  */
1165 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1166 {
1167         u64 msecs = nla_get_u64(nla);
1168
1169         return msecs_to_jiffies((unsigned long) msecs);
1170 }
1171
1172 /**
1173  * nla_get_in_addr - return payload of IPv4 address attribute
1174  * @nla: IPv4 address netlink attribute
1175  */
1176 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1177 {
1178         return *(__be32 *) nla_data(nla);
1179 }
1180
1181 /**
1182  * nla_get_in6_addr - return payload of IPv6 address attribute
1183  * @nla: IPv6 address netlink attribute
1184  */
1185 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1186 {
1187         struct in6_addr tmp;
1188
1189         nla_memcpy(&tmp, nla, sizeof(tmp));
1190         return tmp;
1191 }
1192
1193 /**
1194  * nla_nest_start - Start a new level of nested attributes
1195  * @skb: socket buffer to add attributes to
1196  * @attrtype: attribute type of container
1197  *
1198  * Returns the container attribute
1199  */
1200 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1201 {
1202         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1203
1204         if (nla_put(skb, attrtype, 0, NULL) < 0)
1205                 return NULL;
1206
1207         return start;
1208 }
1209
1210 /**
1211  * nla_nest_end - Finalize nesting of attributes
1212  * @skb: socket buffer the attributes are stored in
1213  * @start: container attribute
1214  *
1215  * Corrects the container attribute header to include the all
1216  * appeneded attributes.
1217  *
1218  * Returns the total data length of the skb.
1219  */
1220 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1221 {
1222         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1223         return skb->len;
1224 }
1225
1226 /**
1227  * nla_nest_cancel - Cancel nesting of attributes
1228  * @skb: socket buffer the message is stored in
1229  * @start: container attribute
1230  *
1231  * Removes the container attribute and including all nested
1232  * attributes. Returns -EMSGSIZE
1233  */
1234 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1235 {
1236         nlmsg_trim(skb, start);
1237 }
1238
1239 /**
1240  * nla_validate_nested - Validate a stream of nested attributes
1241  * @start: container attribute
1242  * @maxtype: maximum attribute type to be expected
1243  * @policy: validation policy
1244  *
1245  * Validates all attributes in the nested attribute stream against the
1246  * specified policy. Attributes with a type exceeding maxtype will be
1247  * ignored. See documenation of struct nla_policy for more details.
1248  *
1249  * Returns 0 on success or a negative error code.
1250  */
1251 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1252                                       const struct nla_policy *policy)
1253 {
1254         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1255 }
1256
1257 /**
1258  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1259  * @skb: socket buffer the message is stored in
1260  *
1261  * Return true if padding is needed to align the next attribute (nla_data()) to
1262  * a 64-bit aligned area.
1263  */
1264 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1265 {
1266 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1267         /* The nlattr header is 4 bytes in size, that's why we test
1268          * if the skb->data _is_ aligned.  A NOP attribute, plus
1269          * nlattr header for next attribute, will make nla_data()
1270          * 8-byte aligned.
1271          */
1272         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1273                 return true;
1274 #endif
1275         return false;
1276 }
1277
1278 /**
1279  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1280  * @skb: socket buffer the message is stored in
1281  * @padattr: attribute type for the padding
1282  *
1283  * Conditionally emit a padding netlink attribute in order to make
1284  * the next attribute we emit have a 64-bit aligned nla_data() area.
1285  * This will only be done in architectures which do not have
1286  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1287  *
1288  * Returns zero on success or a negative error code.
1289  */
1290 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1291 {
1292         if (nla_need_padding_for_64bit(skb) &&
1293             !nla_reserve(skb, padattr, 0))
1294                 return -EMSGSIZE;
1295
1296         return 0;
1297 }
1298
1299 /**
1300  * nla_total_size_64bit - total length of attribute including padding
1301  * @payload: length of payload
1302  */
1303 static inline int nla_total_size_64bit(int payload)
1304 {
1305         return NLA_ALIGN(nla_attr_size(payload))
1306 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1307                 + NLA_ALIGN(nla_attr_size(0))
1308 #endif
1309                 ;
1310 }
1311
1312 /**
1313  * nla_for_each_attr - iterate over a stream of attributes
1314  * @pos: loop counter, set to current attribute
1315  * @head: head of attribute stream
1316  * @len: length of attribute stream
1317  * @rem: initialized to len, holds bytes currently remaining in stream
1318  */
1319 #define nla_for_each_attr(pos, head, len, rem) \
1320         for (pos = head, rem = len; \
1321              nla_ok(pos, rem); \
1322              pos = nla_next(pos, &(rem)))
1323
1324 /**
1325  * nla_for_each_nested - iterate over nested attributes
1326  * @pos: loop counter, set to current attribute
1327  * @nla: attribute containing the nested attributes
1328  * @rem: initialized to len, holds bytes currently remaining in stream
1329  */
1330 #define nla_for_each_nested(pos, nla, rem) \
1331         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1332
1333 /**
1334  * nla_is_last - Test if attribute is last in stream
1335  * @nla: attribute to test
1336  * @rem: bytes remaining in stream
1337  */
1338 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1339 {
1340         return nla->nla_len == rem;
1341 }
1342
1343 #endif