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,
 110  *                 padattr)             add msecs attribute to skb
 111  *   nla_put_in_addr(skb, type, addr)   add IPv4 address attribute to skb
 112  *   nla_put_in6_addr(skb, type, addr)  add IPv6 address attribute to skb
 113  *
 114  * Nested Attributes Construction:
 115  *   nla_nest_start(skb, type)          start a nested attribute
 116  *   nla_nest_end(skb, nla)             finalize a nested attribute
 117  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 118  *
 119  * Attribute Length Calculations:
 120  *   nla_attr_size(payload)             length of attribute w/o padding
 121  *   nla_total_size(payload)            length of attribute w/ padding
 122  *   nla_padlen(payload)                length of padding
 123  *
 124  * Attribute Payload Access:
 125  *   nla_data(nla)                      head of attribute payload
 126  *   nla_len(nla)                       length of attribute payload
 127  *
 128  * Attribute Payload Access for Basic Types:
 129  *   nla_get_u8(nla)                    get payload for a u8 attribute
 130  *   nla_get_u16(nla)                   get payload for a u16 attribute
 131  *   nla_get_u32(nla)                   get payload for a u32 attribute
 132  *   nla_get_u64(nla)                   get payload for a u64 attribute
 133  *   nla_get_s8(nla)                    get payload for a s8 attribute
 134  *   nla_get_s16(nla)                   get payload for a s16 attribute
 135  *   nla_get_s32(nla)                   get payload for a s32 attribute
 136  *   nla_get_s64(nla)                   get payload for a s64 attribute
 137  *   nla_get_flag(nla)                  return 1 if flag is true
 138  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 139  *
 140  * Attribute Misc:
 141  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 142  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 143  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 144  *   nla_strcmp(nla, str)               compare attribute with string
 145  *
 146  * Attribute Parsing:
 147  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 148  *   nla_next(nla, remaining)           get next netlink attribute
 149  *   nla_validate()                     validate a stream of attributes
 150  *   nla_validate_nested()              validate a stream of nested attributes
 151  *   nla_find()                         find attribute in stream of attributes
 152  *   nla_find_nested()                  find attribute in nested attributes
 153  *   nla_parse()                        parse and validate stream of attrs
 154  *   nla_parse_nested()                 parse nested attribuets
 155  *   nla_for_each_attr()                loop over all attributes
 156  *   nla_for_each_nested()              loop over the nested attributes
 157  *=========================================================================
 158  */
 159
 160  /**
 161   * Standard attribute types to specify validation policy
 162   */
 163 enum {
 164         NLA_UNSPEC,
 165         NLA_U8,
 166         NLA_U16,
 167         NLA_U32,
 168         NLA_U64,
 169         NLA_STRING,
 170         NLA_FLAG,
 171         NLA_MSECS,
 172         NLA_NESTED,
 173         NLA_NESTED_COMPAT,
 174         NLA_NUL_STRING,
 175         NLA_BINARY,
 176         NLA_S8,
 177         NLA_S16,
 178         NLA_S32,
 179         NLA_S64,
 180         __NLA_TYPE_MAX,
 181 };
 182
 183 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 184
 185 /**
 186  * struct nla_policy - attribute validation policy
 187  * @type: Type of attribute or NLA_UNSPEC
 188  * @len: Type specific length of payload
 189  *
 190  * Policies are defined as arrays of this struct, the array must be
 191  * accessible by attribute type up to the highest identifier to be expected.
 192  *
 193  * Meaning of `len' field:
 194  *    NLA_STRING           Maximum length of string
 195  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 196  *    NLA_FLAG             Unused
 197  *    NLA_BINARY           Maximum length of attribute payload
 198  *    NLA_NESTED           Don't use `len' field -- length verification is
 199  *                         done by checking len of nested header (or empty)
 200  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 201  *    NLA_U8, NLA_U16,
 202  *    NLA_U32, NLA_U64,
 203  *    NLA_S8, NLA_S16,
 204  *    NLA_S32, NLA_S64,
 205  *    NLA_MSECS            Leaving the length field zero will verify the
 206  *                         given type fits, using it verifies minimum length
 207  *                         just like "All other"
 208  *    All other            Minimum length of attribute payload
 209  *
 210  * Example:
 211  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 212  *      [ATTR_FOO] = { .type = NLA_U16 },
 213  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 214  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 215  * };
 216  */
 217 struct nla_policy {
 218         u16             type;
 219         u16             len;
 220 };
 221
 222 /**
 223  * struct nl_info - netlink source information
 224  * @nlh: Netlink message header of original request
 225  * @portid: Netlink PORTID of requesting application
 226  */
 227 struct nl_info {
 228         struct nlmsghdr         *nlh;
 229         struct net              *nl_net;
 230         u32                     portid;
 231 };
 232
 233 int netlink_rcv_skb(struct sk_buff *skb,
 234                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
 235 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 236                  unsigned int group, int report, gfp_t flags);
 237
 238 int nla_validate(const struct nlattr *head, int len, int maxtype,
 239                  const struct nla_policy *policy);
 240 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 241               int len, const struct nla_policy *policy);
 242 int nla_policy_len(const struct nla_policy *, int);
 243 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 244 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 245 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 246 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 247 int nla_strcmp(const struct nlattr *nla, const char *str);
 248 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 249 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 250                                    int attrlen, int padattr);
 251 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 252 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 253 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 254                                  int attrlen, int padattr);
 255 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 256 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 257                const void *data);
 258 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 259                      const void *data, int padattr);
 260 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 261 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 262 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 263                   const void *data, int padattr);
 264 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 265 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 266
 267 /**************************************************************************
 268  * Netlink Messages
 269  **************************************************************************/
 270
 271 /**
 272  * nlmsg_msg_size - length of netlink message not including padding
 273  * @payload: length of message payload
 274  */
 275 static inline int nlmsg_msg_size(int payload)
 276 {
 277         return NLMSG_HDRLEN + payload;
 278 }
 279
 280 /**
 281  * nlmsg_total_size - length of netlink message including padding
 282  * @payload: length of message payload
 283  */
 284 static inline int nlmsg_total_size(int payload)
 285 {
 286         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 287 }
 288
 289 /**
 290  * nlmsg_padlen - length of padding at the message's tail
 291  * @payload: length of message payload
 292  */
 293 static inline int nlmsg_padlen(int payload)
 294 {
 295         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 296 }
 297
 298 /**
 299  * nlmsg_data - head of message payload
 300  * @nlh: netlink message header
 301  */
 302 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 303 {
 304         return (unsigned char *) nlh + NLMSG_HDRLEN;
 305 }
 306
 307 /**
 308  * nlmsg_len - length of message payload
 309  * @nlh: netlink message header
 310  */
 311 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 312 {
 313         return nlh->nlmsg_len - NLMSG_HDRLEN;
 314 }
 315
 316 /**
 317  * nlmsg_attrdata - head of attributes data
 318  * @nlh: netlink message header
 319  * @hdrlen: length of family specific header
 320  */
 321 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 322                                             int hdrlen)
 323 {
 324         unsigned char *data = nlmsg_data(nlh);
 325         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 326 }
 327
 328 /**
 329  * nlmsg_attrlen - length of attributes data
 330  * @nlh: netlink message header
 331  * @hdrlen: length of family specific header
 332  */
 333 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 334 {
 335         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 336 }
 337
 338 /**
 339  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 340  * @nlh: netlink message header
 341  * @remaining: number of bytes remaining in message stream
 342  */
 343 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 344 {
 345         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 346                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 347                 nlh->nlmsg_len <= remaining);
 348 }
 349
 350 /**
 351  * nlmsg_next - next netlink message in message stream
 352  * @nlh: netlink message header
 353  * @remaining: number of bytes remaining in message stream
 354  *
 355  * Returns the next netlink message in the message stream and
 356  * decrements remaining by the size of the current message.
 357  */
 358 static inline struct nlmsghdr *
 359 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 360 {
 361         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 362
 363         *remaining -= totlen;
 364
 365         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 366 }
 367
 368 /**
 369  * nlmsg_parse - parse attributes of a netlink message
 370  * @nlh: netlink message header
 371  * @hdrlen: length of family specific header
 372  * @tb: destination array with maxtype+1 elements
 373  * @maxtype: maximum attribute type to be expected
 374  * @policy: validation policy
 375  *
 376  * See nla_parse()
 377  */
 378 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 379                               struct nlattr *tb[], int maxtype,
 380                               const struct nla_policy *policy)
 381 {
 382         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 383                 return -EINVAL;
 384
 385         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 386                          nlmsg_attrlen(nlh, hdrlen), policy);
 387 }
 388
 389 /**
 390  * nlmsg_find_attr - find a specific attribute in a netlink message
 391  * @nlh: netlink message header
 392  * @hdrlen: length of familiy specific header
 393  * @attrtype: type of attribute to look for
 394  *
 395  * Returns the first attribute which matches the specified type.
 396  */
 397 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 398                                              int hdrlen, int attrtype)
 399 {
 400         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 401                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 402 }
 403
 404 /**
 405  * nlmsg_validate - validate a netlink message including attributes
 406  * @nlh: netlinket message header
 407  * @hdrlen: length of familiy specific header
 408  * @maxtype: maximum attribute type to be expected
 409  * @policy: validation policy
 410  */
 411 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 412                                  int hdrlen, int maxtype,
 413                                  const struct nla_policy *policy)
 414 {
 415         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 416                 return -EINVAL;
 417
 418         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 419                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 420 }
 421
 422 /**
 423  * nlmsg_report - need to report back to application?
 424  * @nlh: netlink message header
 425  *
 426  * Returns 1 if a report back to the application is requested.
 427  */
 428 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 429 {
 430         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 431 }
 432
 433 /**
 434  * nlmsg_for_each_attr - iterate over a stream of attributes
 435  * @pos: loop counter, set to current attribute
 436  * @nlh: netlink message header
 437  * @hdrlen: length of familiy specific header
 438  * @rem: initialized to len, holds bytes currently remaining in stream
 439  */
 440 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 441         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 442                           nlmsg_attrlen(nlh, hdrlen), rem)
 443
 444 /**
 445  * nlmsg_put - Add a new netlink message to an skb
 446  * @skb: socket buffer to store message in
 447  * @portid: netlink PORTID of requesting application
 448  * @seq: sequence number of message
 449  * @type: message type
 450  * @payload: length of message payload
 451  * @flags: message flags
 452  *
 453  * Returns NULL if the tailroom of the skb is insufficient to store
 454  * the message header and payload.
 455  */
 456 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 457                                          int type, int payload, int flags)
 458 {
 459         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 460                 return NULL;
 461
 462         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 463 }
 464
 465 /**
 466  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 467  * @skb: socket buffer to store message in
 468  * @cb: netlink callback
 469  * @type: message type
 470  * @payload: length of message payload
 471  * @flags: message flags
 472  *
 473  * Returns NULL if the tailroom of the skb is insufficient to store
 474  * the message header and payload.
 475  */
 476 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 477                                                 struct netlink_callback *cb,
 478                                                 int type, int payload,
 479                                                 int flags)
 480 {
 481         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 482                          type, payload, flags);
 483 }
 484
 485 /**
 486  * nlmsg_new - Allocate a new netlink message
 487  * @payload: size of the message payload
 488  * @flags: the type of memory to allocate.
 489  *
 490  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 491  * and a good default is needed.
 492  */
 493 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 494 {
 495         return alloc_skb(nlmsg_total_size(payload), flags);
 496 }
 497
 498 /**
 499  * nlmsg_end - Finalize a netlink message
 500  * @skb: socket buffer the message is stored in
 501  * @nlh: netlink message header
 502  *
 503  * Corrects the netlink message header to include the appeneded
 504  * attributes. Only necessary if attributes have been added to
 505  * the message.
 506  */
 507 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 508 {
 509         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 510 }
 511
 512 /**
 513  * nlmsg_get_pos - return current position in netlink message
 514  * @skb: socket buffer the message is stored in
 515  *
 516  * Returns a pointer to the current tail of the message.
 517  */
 518 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 519 {
 520         return skb_tail_pointer(skb);
 521 }
 522
 523 /**
 524  * nlmsg_trim - Trim message to a mark
 525  * @skb: socket buffer the message is stored in
 526  * @mark: mark to trim to
 527  *
 528  * Trims the message to the provided mark.
 529  */
 530 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 531 {
 532         if (mark) {
 533                 WARN_ON((unsigned char *) mark < skb->data);
 534                 skb_trim(skb, (unsigned char *) mark - skb->data);
 535         }
 536 }
 537
 538 /**
 539  * nlmsg_cancel - Cancel construction of a netlink message
 540  * @skb: socket buffer the message is stored in
 541  * @nlh: netlink message header
 542  *
 543  * Removes the complete netlink message including all
 544  * attributes from the socket buffer again.
 545  */
 546 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 547 {
 548         nlmsg_trim(skb, nlh);
 549 }
 550
 551 /**
 552  * nlmsg_free - free a netlink message
 553  * @skb: socket buffer of netlink message
 554  */
 555 static inline void nlmsg_free(struct sk_buff *skb)
 556 {
 557         kfree_skb(skb);
 558 }
 559
 560 /**
 561  * nlmsg_multicast - multicast a netlink message
 562  * @sk: netlink socket to spread messages to
 563  * @skb: netlink message as socket buffer
 564  * @portid: own netlink portid to avoid sending to yourself
 565  * @group: multicast group id
 566  * @flags: allocation flags
 567  */
 568 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 569                                   u32 portid, unsigned int group, gfp_t flags)
 570 {
 571         int err;
 572
 573         NETLINK_CB(skb).dst_group = group;
 574
 575         err = netlink_broadcast(sk, skb, portid, group, flags);
 576         if (err > 0)
 577                 err = 0;
 578
 579         return err;
 580 }
 581
 582 /**
 583  * nlmsg_unicast - unicast a netlink message
 584  * @sk: netlink socket to spread message to
 585  * @skb: netlink message as socket buffer
 586  * @portid: netlink portid of the destination socket
 587  */
 588 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 589 {
 590         int err;
 591
 592         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 593         if (err > 0)
 594                 err = 0;
 595
 596         return err;
 597 }
 598
 599 /**
 600  * nlmsg_for_each_msg - iterate over a stream of messages
 601  * @pos: loop counter, set to current message
 602  * @head: head of message stream
 603  * @len: length of message stream
 604  * @rem: initialized to len, holds bytes currently remaining in stream
 605  */
 606 #define nlmsg_for_each_msg(pos, head, len, rem) \
 607         for (pos = head, rem = len; \
 608              nlmsg_ok(pos, rem); \
 609              pos = nlmsg_next(pos, &(rem)))
 610
 611 /**
 612  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 613  * @cb: netlink callback structure that stores the sequence number
 614  * @nlh: netlink message header to write the flag to
 615  *
 616  * This function checks if the sequence (generation) number changed during dump
 617  * and if it did, advertises it in the netlink message header.
 618  *
 619  * The correct way to use it is to set cb->seq to the generation counter when
 620  * all locks for dumping have been acquired, and then call this function for
 621  * each message that is generated.
 622  *
 623  * Note that due to initialisation concerns, 0 is an invalid sequence number
 624  * and must not be used by code that uses this functionality.
 625  */
 626 static inline void
 627 nl_dump_check_consistent(struct netlink_callback *cb,
 628                          struct nlmsghdr *nlh)
 629 {
 630         if (cb->prev_seq && cb->seq != cb->prev_seq)
 631                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 632         cb->prev_seq = cb->seq;
 633 }
 634
 635 /**************************************************************************
 636  * Netlink Attributes
 637  **************************************************************************/
 638
 639 /**
 640  * nla_attr_size - length of attribute not including padding
 641  * @payload: length of payload
 642  */
 643 static inline int nla_attr_size(int payload)
 644 {
 645         return NLA_HDRLEN + payload;
 646 }
 647
 648 /**
 649  * nla_total_size - total length of attribute including padding
 650  * @payload: length of payload
 651  */
 652 static inline int nla_total_size(int payload)
 653 {
 654         return NLA_ALIGN(nla_attr_size(payload));
 655 }
 656
 657 /**
 658  * nla_padlen - length of padding at the tail of attribute
 659  * @payload: length of payload
 660  */
 661 static inline int nla_padlen(int payload)
 662 {
 663         return nla_total_size(payload) - nla_attr_size(payload);
 664 }
 665
 666 /**
 667  * nla_type - attribute type
 668  * @nla: netlink attribute
 669  */
 670 static inline int nla_type(const struct nlattr *nla)
 671 {
 672         return nla->nla_type & NLA_TYPE_MASK;
 673 }
 674
 675 /**
 676  * nla_data - head of payload
 677  * @nla: netlink attribute
 678  */
 679 static inline void *nla_data(const struct nlattr *nla)
 680 {
 681         return (char *) nla + NLA_HDRLEN;
 682 }
 683
 684 /**
 685  * nla_len - length of payload
 686  * @nla: netlink attribute
 687  */
 688 static inline int nla_len(const struct nlattr *nla)
 689 {
 690         return nla->nla_len - NLA_HDRLEN;
 691 }
 692
 693 /**
 694  * nla_ok - check if the netlink attribute fits into the remaining bytes
 695  * @nla: netlink attribute
 696  * @remaining: number of bytes remaining in attribute stream
 697  */
 698 static inline int nla_ok(const struct nlattr *nla, int remaining)
 699 {
 700         return remaining >= (int) sizeof(*nla) &&
 701                nla->nla_len >= sizeof(*nla) &&
 702                nla->nla_len <= remaining;
 703 }
 704
 705 /**
 706  * nla_next - next netlink attribute in attribute stream
 707  * @nla: netlink attribute
 708  * @remaining: number of bytes remaining in attribute stream
 709  *
 710  * Returns the next netlink attribute in the attribute stream and
 711  * decrements remaining by the size of the current attribute.
 712  */
 713 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 714 {
 715         int totlen = NLA_ALIGN(nla->nla_len);
 716
 717         *remaining -= totlen;
 718         return (struct nlattr *) ((char *) nla + totlen);
 719 }
 720
 721 /**
 722  * nla_find_nested - find attribute in a set of nested attributes
 723  * @nla: attribute containing the nested attributes
 724  * @attrtype: type of attribute to look for
 725  *
 726  * Returns the first attribute which matches the specified type.
 727  */
 728 static inline struct nlattr *
 729 nla_find_nested(const struct nlattr *nla, int attrtype)
 730 {
 731         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 732 }
 733
 734 /**
 735  * nla_parse_nested - parse nested attributes
 736  * @tb: destination array with maxtype+1 elements
 737  * @maxtype: maximum attribute type to be expected
 738  * @nla: attribute containing the nested attributes
 739  * @policy: validation policy
 740  *
 741  * See nla_parse()
 742  */
 743 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 744                                    const struct nlattr *nla,
 745                                    const struct nla_policy *policy)
 746 {
 747         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 748 }
 749
 750 /**
 751  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 752  * @skb: socket buffer to add attribute to
 753  * @attrtype: attribute type
 754  * @value: numeric value
 755  */
 756 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 757 {
 758         return nla_put(skb, attrtype, sizeof(u8), &value);
 759 }
 760
 761 /**
 762  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 763  * @skb: socket buffer to add attribute to
 764  * @attrtype: attribute type
 765  * @value: numeric value
 766  */
 767 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 768 {
 769         return nla_put(skb, attrtype, sizeof(u16), &value);
 770 }
 771
 772 /**
 773  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 774  * @skb: socket buffer to add attribute to
 775  * @attrtype: attribute type
 776  * @value: numeric value
 777  */
 778 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 779 {
 780         return nla_put(skb, attrtype, sizeof(__be16), &value);
 781 }
 782
 783 /**
 784  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 785  * @skb: socket buffer to add attribute to
 786  * @attrtype: attribute type
 787  * @value: numeric value
 788  */
 789 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 790 {
 791         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 792 }
 793
 794 /**
 795  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 796  * @skb: socket buffer to add attribute to
 797  * @attrtype: attribute type
 798  * @value: numeric value
 799  */
 800 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 801 {
 802         return nla_put(skb, attrtype, sizeof(__le16), &value);
 803 }
 804
 805 /**
 806  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 807  * @skb: socket buffer to add attribute to
 808  * @attrtype: attribute type
 809  * @value: numeric value
 810  */
 811 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 812 {
 813         return nla_put(skb, attrtype, sizeof(u32), &value);
 814 }
 815
 816 /**
 817  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 818  * @skb: socket buffer to add attribute to
 819  * @attrtype: attribute type
 820  * @value: numeric value
 821  */
 822 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 823 {
 824         return nla_put(skb, attrtype, sizeof(__be32), &value);
 825 }
 826
 827 /**
 828  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 829  * @skb: socket buffer to add attribute to
 830  * @attrtype: attribute type
 831  * @value: numeric value
 832  */
 833 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 834 {
 835         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 836 }
 837
 838 /**
 839  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 840  * @skb: socket buffer to add attribute to
 841  * @attrtype: attribute type
 842  * @value: numeric value
 843  */
 844 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 845 {
 846         return nla_put(skb, attrtype, sizeof(__le32), &value);
 847 }
 848
 849 /**
 850  * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
 851  * @skb: socket buffer to add attribute to
 852  * @attrtype: attribute type
 853  * @value: numeric value
 854  */
 855 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 856 {
 857         return nla_put(skb, attrtype, sizeof(u64), &value);
 858 }
 859
 860 /**
 861  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
 862  * @skb: socket buffer to add attribute to
 863  * @attrtype: attribute type
 864  * @value: numeric value
 865  * @padattr: attribute type for the padding
 866  */
 867 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
 868                                     u64 value, int padattr)
 869 {
 870         return nla_put_64bit(skb, attrtype, sizeof(u64), &value, padattr);
 871 }
 872
 873 /**
 874  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 875  * @skb: socket buffer to add attribute to
 876  * @attrtype: attribute type
 877  * @value: numeric value
 878  * @padattr: attribute type for the padding
 879  */
 880 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
 881                                int padattr)
 882 {
 883         return nla_put_64bit(skb, attrtype, sizeof(__be64), &value, padattr);
 884 }
 885
 886 /**
 887  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb 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_net64(struct sk_buff *skb, int attrtype, __be64 value,
 894                                 int padattr)
 895 {
 896         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value,
 897                             padattr);
 898 }
 899
 900 /**
 901  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 902  * @skb: socket buffer to add attribute to
 903  * @attrtype: attribute type
 904  * @value: numeric value
 905  * @padattr: attribute type for the padding
 906  */
 907 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
 908                                int padattr)
 909 {
 910         return nla_put_64bit(skb, attrtype, sizeof(__le64), &value, padattr);
 911 }
 912
 913 /**
 914  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 915  * @skb: socket buffer to add attribute to
 916  * @attrtype: attribute type
 917  * @value: numeric value
 918  */
 919 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 920 {
 921         return nla_put(skb, attrtype, sizeof(s8), &value);
 922 }
 923
 924 /**
 925  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 926  * @skb: socket buffer to add attribute to
 927  * @attrtype: attribute type
 928  * @value: numeric value
 929  */
 930 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 931 {
 932         return nla_put(skb, attrtype, sizeof(s16), &value);
 933 }
 934
 935 /**
 936  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 937  * @skb: socket buffer to add attribute to
 938  * @attrtype: attribute type
 939  * @value: numeric value
 940  */
 941 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 942 {
 943         return nla_put(skb, attrtype, sizeof(s32), &value);
 944 }
 945
 946 /**
 947  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 948  * @skb: socket buffer to add attribute to
 949  * @attrtype: attribute type
 950  * @value: numeric value
 951  * @padattr: attribute type for the padding
 952  */
 953 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
 954                               int padattr)
 955 {
 956         return nla_put_64bit(skb, attrtype, sizeof(s64), &value, padattr);
 957 }
 958
 959 /**
 960  * nla_put_string - Add a string netlink attribute to a socket buffer
 961  * @skb: socket buffer to add attribute to
 962  * @attrtype: attribute type
 963  * @str: NUL terminated string
 964  */
 965 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 966                                  const char *str)
 967 {
 968         return nla_put(skb, attrtype, strlen(str) + 1, str);
 969 }
 970
 971 /**
 972  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 973  * @skb: socket buffer to add attribute to
 974  * @attrtype: attribute type
 975  */
 976 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 977 {
 978         return nla_put(skb, attrtype, 0, NULL);
 979 }
 980
 981 /**
 982  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
 983  * @skb: socket buffer to add attribute to
 984  * @attrtype: attribute type
 985  * @njiffies: number of jiffies to convert to msecs
 986  * @padattr: attribute type for the padding
 987  */
 988 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 989                                 unsigned long njiffies, int padattr)
 990 {
 991         u64 tmp = jiffies_to_msecs(njiffies);
 992
 993         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
 994 }
 995
 996 /**
 997  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 998  * buffer
 999  * @skb: socket buffer to add attribute to
1000  * @attrtype: attribute type
1001  * @addr: IPv4 address
1002  */
1003 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
1004                                   __be32 addr)
1005 {
1006         return nla_put_be32(skb, attrtype, addr);
1007 }
1008
1009 /**
1010  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1011  * buffer
1012  * @skb: socket buffer to add attribute to
1013  * @attrtype: attribute type
1014  * @addr: IPv6 address
1015  */
1016 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1017                                    const struct in6_addr *addr)
1018 {
1019         return nla_put(skb, attrtype, sizeof(*addr), addr);
1020 }
1021
1022 /**
1023  * nla_get_u32 - return payload of u32 attribute
1024  * @nla: u32 netlink attribute
1025  */
1026 static inline u32 nla_get_u32(const struct nlattr *nla)
1027 {
1028         return *(u32 *) nla_data(nla);
1029 }
1030
1031 /**
1032  * nla_get_be32 - return payload of __be32 attribute
1033  * @nla: __be32 netlink attribute
1034  */
1035 static inline __be32 nla_get_be32(const struct nlattr *nla)
1036 {
1037         return *(__be32 *) nla_data(nla);
1038 }
1039
1040 /**
1041  * nla_get_le32 - return payload of __le32 attribute
1042  * @nla: __le32 netlink attribute
1043  */
1044 static inline __le32 nla_get_le32(const struct nlattr *nla)
1045 {
1046         return *(__le32 *) nla_data(nla);
1047 }
1048
1049 /**
1050  * nla_get_u16 - return payload of u16 attribute
1051  * @nla: u16 netlink attribute
1052  */
1053 static inline u16 nla_get_u16(const struct nlattr *nla)
1054 {
1055         return *(u16 *) nla_data(nla);
1056 }
1057
1058 /**
1059  * nla_get_be16 - return payload of __be16 attribute
1060  * @nla: __be16 netlink attribute
1061  */
1062 static inline __be16 nla_get_be16(const struct nlattr *nla)
1063 {
1064         return *(__be16 *) nla_data(nla);
1065 }
1066
1067 /**
1068  * nla_get_le16 - return payload of __le16 attribute
1069  * @nla: __le16 netlink attribute
1070  */
1071 static inline __le16 nla_get_le16(const struct nlattr *nla)
1072 {
1073         return *(__le16 *) nla_data(nla);
1074 }
1075
1076 /**
1077  * nla_get_u8 - return payload of u8 attribute
1078  * @nla: u8 netlink attribute
1079  */
1080 static inline u8 nla_get_u8(const struct nlattr *nla)
1081 {
1082         return *(u8 *) nla_data(nla);
1083 }
1084
1085 /**
1086  * nla_get_u64 - return payload of u64 attribute
1087  * @nla: u64 netlink attribute
1088  */
1089 static inline u64 nla_get_u64(const struct nlattr *nla)
1090 {
1091         u64 tmp;
1092
1093         nla_memcpy(&tmp, nla, sizeof(tmp));
1094
1095         return tmp;
1096 }
1097
1098 /**
1099  * nla_get_be64 - return payload of __be64 attribute
1100  * @nla: __be64 netlink attribute
1101  */
1102 static inline __be64 nla_get_be64(const struct nlattr *nla)
1103 {
1104         __be64 tmp;
1105
1106         nla_memcpy(&tmp, nla, sizeof(tmp));
1107
1108         return tmp;
1109 }
1110
1111 /**
1112  * nla_get_le64 - return payload of __le64 attribute
1113  * @nla: __le64 netlink attribute
1114  */
1115 static inline __le64 nla_get_le64(const struct nlattr *nla)
1116 {
1117         return *(__le64 *) nla_data(nla);
1118 }
1119
1120 /**
1121  * nla_get_s32 - return payload of s32 attribute
1122  * @nla: s32 netlink attribute
1123  */
1124 static inline s32 nla_get_s32(const struct nlattr *nla)
1125 {
1126         return *(s32 *) nla_data(nla);
1127 }
1128
1129 /**
1130  * nla_get_s16 - return payload of s16 attribute
1131  * @nla: s16 netlink attribute
1132  */
1133 static inline s16 nla_get_s16(const struct nlattr *nla)
1134 {
1135         return *(s16 *) nla_data(nla);
1136 }
1137
1138 /**
1139  * nla_get_s8 - return payload of s8 attribute
1140  * @nla: s8 netlink attribute
1141  */
1142 static inline s8 nla_get_s8(const struct nlattr *nla)
1143 {
1144         return *(s8 *) nla_data(nla);
1145 }
1146
1147 /**
1148  * nla_get_s64 - return payload of s64 attribute
1149  * @nla: s64 netlink attribute
1150  */
1151 static inline s64 nla_get_s64(const struct nlattr *nla)
1152 {
1153         s64 tmp;
1154
1155         nla_memcpy(&tmp, nla, sizeof(tmp));
1156
1157         return tmp;
1158 }
1159
1160 /**
1161  * nla_get_flag - return payload of flag attribute
1162  * @nla: flag netlink attribute
1163  */
1164 static inline int nla_get_flag(const struct nlattr *nla)
1165 {
1166         return !!nla;
1167 }
1168
1169 /**
1170  * nla_get_msecs - return payload of msecs attribute
1171  * @nla: msecs netlink attribute
1172  *
1173  * Returns the number of milliseconds in jiffies.
1174  */
1175 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1176 {
1177         u64 msecs = nla_get_u64(nla);
1178
1179         return msecs_to_jiffies((unsigned long) msecs);
1180 }
1181
1182 /**
1183  * nla_get_in_addr - return payload of IPv4 address attribute
1184  * @nla: IPv4 address netlink attribute
1185  */
1186 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1187 {
1188         return *(__be32 *) nla_data(nla);
1189 }
1190
1191 /**
1192  * nla_get_in6_addr - return payload of IPv6 address attribute
1193  * @nla: IPv6 address netlink attribute
1194  */
1195 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1196 {
1197         struct in6_addr tmp;
1198
1199         nla_memcpy(&tmp, nla, sizeof(tmp));
1200         return tmp;
1201 }
1202
1203 /**
1204  * nla_nest_start - Start a new level of nested attributes
1205  * @skb: socket buffer to add attributes to
1206  * @attrtype: attribute type of container
1207  *
1208  * Returns the container attribute
1209  */
1210 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1211 {
1212         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1213
1214         if (nla_put(skb, attrtype, 0, NULL) < 0)
1215                 return NULL;
1216
1217         return start;
1218 }
1219
1220 /**
1221  * nla_nest_end - Finalize nesting of attributes
1222  * @skb: socket buffer the attributes are stored in
1223  * @start: container attribute
1224  *
1225  * Corrects the container attribute header to include the all
1226  * appeneded attributes.
1227  *
1228  * Returns the total data length of the skb.
1229  */
1230 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1231 {
1232         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1233         return skb->len;
1234 }
1235
1236 /**
1237  * nla_nest_cancel - Cancel nesting of attributes
1238  * @skb: socket buffer the message is stored in
1239  * @start: container attribute
1240  *
1241  * Removes the container attribute and including all nested
1242  * attributes. Returns -EMSGSIZE
1243  */
1244 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1245 {
1246         nlmsg_trim(skb, start);
1247 }
1248
1249 /**
1250  * nla_validate_nested - Validate a stream of nested attributes
1251  * @start: container attribute
1252  * @maxtype: maximum attribute type to be expected
1253  * @policy: validation policy
1254  *
1255  * Validates all attributes in the nested attribute stream against the
1256  * specified policy. Attributes with a type exceeding maxtype will be
1257  * ignored. See documenation of struct nla_policy for more details.
1258  *
1259  * Returns 0 on success or a negative error code.
1260  */
1261 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1262                                       const struct nla_policy *policy)
1263 {
1264         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1265 }
1266
1267 /**
1268  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1269  * @skb: socket buffer the message is stored in
1270  *
1271  * Return true if padding is needed to align the next attribute (nla_data()) to
1272  * a 64-bit aligned area.
1273  */
1274 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1275 {
1276 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1277         /* The nlattr header is 4 bytes in size, that's why we test
1278          * if the skb->data _is_ aligned.  A NOP attribute, plus
1279          * nlattr header for next attribute, will make nla_data()
1280          * 8-byte aligned.
1281          */
1282         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1283                 return true;
1284 #endif
1285         return false;
1286 }
1287
1288 /**
1289  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1290  * @skb: socket buffer the message is stored in
1291  * @padattr: attribute type for the padding
1292  *
1293  * Conditionally emit a padding netlink attribute in order to make
1294  * the next attribute we emit have a 64-bit aligned nla_data() area.
1295  * This will only be done in architectures which do not have
1296  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1297  *
1298  * Returns zero on success or a negative error code.
1299  */
1300 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1301 {
1302         if (nla_need_padding_for_64bit(skb) &&
1303             !nla_reserve(skb, padattr, 0))
1304                 return -EMSGSIZE;
1305
1306         return 0;
1307 }
1308
1309 /**
1310  * nla_total_size_64bit - total length of attribute including padding
1311  * @payload: length of payload
1312  */
1313 static inline int nla_total_size_64bit(int payload)
1314 {
1315         return NLA_ALIGN(nla_attr_size(payload))
1316 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1317                 + NLA_ALIGN(nla_attr_size(0))
1318 #endif
1319                 ;
1320 }
1321
1322 /**
1323  * nla_for_each_attr - iterate over a stream of attributes
1324  * @pos: loop counter, set to current attribute
1325  * @head: head of attribute stream
1326  * @len: length of attribute stream
1327  * @rem: initialized to len, holds bytes currently remaining in stream
1328  */
1329 #define nla_for_each_attr(pos, head, len, rem) \
1330         for (pos = head, rem = len; \
1331              nla_ok(pos, rem); \
1332              pos = nla_next(pos, &(rem)))
1333
1334 /**
1335  * nla_for_each_nested - iterate over nested attributes
1336  * @pos: loop counter, set to current attribute
1337  * @nla: attribute containing the nested attributes
1338  * @rem: initialized to len, holds bytes currently remaining in stream
1339  */
1340 #define nla_for_each_nested(pos, nla, rem) \
1341         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1342
1343 /**
1344  * nla_is_last - Test if attribute is last in stream
1345  * @nla: attribute to test
1346  * @rem: bytes remaining in stream
1347  */
1348 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1349 {
1350         return nla->nla_len == rem;
1351 }
1352
1353 #endif