include/net/netlink.h

   1 #ifndef __NET_NETLINK_H
   2 #define __NET_NETLINK_H
   3
   4 #include <linux/types.h>
   5 #include <linux/netlink.h>
   6 #include <linux/jiffies.h>
   7 #include <linux/in6.h>
   8
   9 /* ========================================================================
  10  *         Netlink Messages and Attributes Interface (As Seen On TV)
  11  * ------------------------------------------------------------------------
  12  *                          Messages Interface
  13  * ------------------------------------------------------------------------
  14  *
  15  * Message Format:
  16  *    <--- nlmsg_total_size(payload)  --->
  17  *    <-- nlmsg_msg_size(payload) ->
  18  *   +----------+- - -+-------------+- - -+-------- - -
  19  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  20  *   +----------+- - -+-------------+- - -+-------- - -
  21  *   nlmsg_data(nlh)---^                   ^
  22  *   nlmsg_next(nlh)-----------------------+
  23  *
  24  * Payload Format:
  25  *    <---------------------- nlmsg_len(nlh) --------------------->
  26  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  27  *   +----------------------+- - -+--------------------------------+
  28  *   |     Family Header    | Pad |           Attributes           |
  29  *   +----------------------+- - -+--------------------------------+
  30  *   nlmsg_attrdata(nlh, hdrlen)---^
  31  *
  32  * Data Structures:
  33  *   struct nlmsghdr                    netlink message header
  34  *
  35  * Message Construction:
  36  *   nlmsg_new()                        create a new netlink message
  37  *   nlmsg_put()                        add a netlink message to an skb
  38  *   nlmsg_put_answer()                 callback based nlmsg_put()
  39  *   nlmsg_end()                        finalize netlink message
  40  *   nlmsg_get_pos()                    return current position in message
  41  *   nlmsg_trim()                       trim part of message
  42  *   nlmsg_cancel()                     cancel message construction
  43  *   nlmsg_free()                       free a netlink message
  44  *
  45  * Message Sending:
  46  *   nlmsg_multicast()                  multicast message to several groups
  47  *   nlmsg_unicast()                    unicast a message to a single socket
  48  *   nlmsg_notify()                     send notification message
  49  *
  50  * Message Length Calculations:
  51  *   nlmsg_msg_size(payload)            length of message w/o padding
  52  *   nlmsg_total_size(payload)          length of message w/ padding
  53  *   nlmsg_padlen(payload)              length of padding at tail
  54  *
  55  * Message Payload Access:
  56  *   nlmsg_data(nlh)                    head of message payload
  57  *   nlmsg_len(nlh)                     length of message payload
  58  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  59  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  60  *
  61  * Message Parsing:
  62  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  63  *   nlmsg_next(nlh, remaining)         get next netlink message
  64  *   nlmsg_parse()                      parse attributes of a message
  65  *   nlmsg_find_attr()                  find an attribute in a message
  66  *   nlmsg_for_each_msg()               loop over all messages
  67  *   nlmsg_validate()                   validate netlink message incl. attrs
  68  *   nlmsg_for_each_attr()              loop over all attributes
  69  *
  70  * Misc:
  71  *   nlmsg_report()                     report back to application?
  72  *
  73  * ------------------------------------------------------------------------
  74  *                          Attributes Interface
  75  * ------------------------------------------------------------------------
  76  *
  77  * Attribute Format:
  78  *    <------- nla_total_size(payload) ------->
  79  *    <---- nla_attr_size(payload) ----->
  80  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  81  *   |  Header  | Pad |     Payload      | Pad |  Header
  82  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  83  *                     <- nla_len(nla) ->      ^
  84  *   nla_data(nla)----^                        |
  85  *   nla_next(nla)-----------------------------'
  86  *
  87  * Data Structures:
  88  *   struct nlattr                      netlink attribute header
  89  *
  90  * Attribute Construction:
  91  *   nla_reserve(skb, type, len)        reserve room for an attribute
  92  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  93  *   nla_put(skb, type, len, data)      add attribute to skb
  94  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  95  *   nla_append(skb, len, data)         append data to skb
  96  *
  97  * Attribute Construction for Basic Types:
  98  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  99  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
 100  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
 101  *   nla_put_u64_64bits(skb, type,
 102  *                      value, padattr) add u64 attribute to skb
 103  *   nla_put_s8(skb, type, value)       add s8 attribute to skb
 104  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
 105  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
 106  *   nla_put_s64(skb, type, value,
 107  *               padattr)               add s64 attribute to skb
 108  *   nla_put_string(skb, type, str)     add string attribute to skb
 109  *   nla_put_flag(skb, type)            add flag attribute to skb
 110  *   nla_put_msecs(skb, type, jiffies,
 111  *                 padattr)             add msecs attribute to skb
 112  *   nla_put_in_addr(skb, type, addr)   add IPv4 address attribute to skb
 113  *   nla_put_in6_addr(skb, type, addr)  add IPv6 address attribute to skb
 114  *
 115  * Nested Attributes Construction:
 116  *   nla_nest_start(skb, type)          start a nested attribute
 117  *   nla_nest_end(skb, nla)             finalize a nested attribute
 118  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 119  *
 120  * Attribute Length Calculations:
 121  *   nla_attr_size(payload)             length of attribute w/o padding
 122  *   nla_total_size(payload)            length of attribute w/ padding
 123  *   nla_padlen(payload)                length of padding
 124  *
 125  * Attribute Payload Access:
 126  *   nla_data(nla)                      head of attribute payload
 127  *   nla_len(nla)                       length of attribute payload
 128  *
 129  * Attribute Payload Access for Basic Types:
 130  *   nla_get_u8(nla)                    get payload for a u8 attribute
 131  *   nla_get_u16(nla)                   get payload for a u16 attribute
 132  *   nla_get_u32(nla)                   get payload for a u32 attribute
 133  *   nla_get_u64(nla)                   get payload for a u64 attribute
 134  *   nla_get_s8(nla)                    get payload for a s8 attribute
 135  *   nla_get_s16(nla)                   get payload for a s16 attribute
 136  *   nla_get_s32(nla)                   get payload for a s32 attribute
 137  *   nla_get_s64(nla)                   get payload for a s64 attribute
 138  *   nla_get_flag(nla)                  return 1 if flag is true
 139  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 140  *
 141  * Attribute Misc:
 142  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 143  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 144  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 145  *   nla_strcmp(nla, str)               compare attribute with string
 146  *
 147  * Attribute Parsing:
 148  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 149  *   nla_next(nla, remaining)           get next netlink attribute
 150  *   nla_validate()                     validate a stream of attributes
 151  *   nla_validate_nested()              validate a stream of nested attributes
 152  *   nla_find()                         find attribute in stream of attributes
 153  *   nla_find_nested()                  find attribute in nested attributes
 154  *   nla_parse()                        parse and validate stream of attrs
 155  *   nla_parse_nested()                 parse nested attribuets
 156  *   nla_for_each_attr()                loop over all attributes
 157  *   nla_for_each_nested()              loop over the nested attributes
 158  *=========================================================================
 159  */
 160
 161  /**
 162   * Standard attribute types to specify validation policy
 163   */
 164 enum {
 165         NLA_UNSPEC,
 166         NLA_U8,
 167         NLA_U16,
 168         NLA_U32,
 169         NLA_U64,
 170         NLA_STRING,
 171         NLA_FLAG,
 172         NLA_MSECS,
 173         NLA_NESTED,
 174         NLA_NESTED_COMPAT,
 175         NLA_NUL_STRING,
 176         NLA_BINARY,
 177         NLA_S8,
 178         NLA_S16,
 179         NLA_S32,
 180         NLA_S64,
 181         __NLA_TYPE_MAX,
 182 };
 183
 184 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 185
 186 /**
 187  * struct nla_policy - attribute validation policy
 188  * @type: Type of attribute or NLA_UNSPEC
 189  * @len: Type specific length of payload
 190  *
 191  * Policies are defined as arrays of this struct, the array must be
 192  * accessible by attribute type up to the highest identifier to be expected.
 193  *
 194  * Meaning of `len' field:
 195  *    NLA_STRING           Maximum length of string
 196  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 197  *    NLA_FLAG             Unused
 198  *    NLA_BINARY           Maximum length of attribute payload
 199  *    NLA_NESTED           Don't use `len' field -- length verification is
 200  *                         done by checking len of nested header (or empty)
 201  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 202  *    NLA_U8, NLA_U16,
 203  *    NLA_U32, NLA_U64,
 204  *    NLA_S8, NLA_S16,
 205  *    NLA_S32, NLA_S64,
 206  *    NLA_MSECS            Leaving the length field zero will verify the
 207  *                         given type fits, using it verifies minimum length
 208  *                         just like "All other"
 209  *    All other            Minimum length of attribute payload
 210  *
 211  * Example:
 212  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 213  *      [ATTR_FOO] = { .type = NLA_U16 },
 214  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 215  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 216  * };
 217  */
 218 struct nla_policy {
 219         u16             type;
 220         u16             len;
 221 };
 222
 223 /**
 224  * struct nl_info - netlink source information
 225  * @nlh: Netlink message header of original request
 226  * @portid: Netlink PORTID of requesting application
 227  */
 228 struct nl_info {
 229         struct nlmsghdr         *nlh;
 230         struct net              *nl_net;
 231         u32                     portid;
 232         bool                    skip_notify;
 233 };
 234
 235 int netlink_rcv_skb(struct sk_buff *skb,
 236                     int (*cb)(struct sk_buff *, struct nlmsghdr *,
 237                               struct netlink_ext_ack *));
 238 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 239                  unsigned int group, int report, gfp_t flags);
 240
 241 int nla_validate(const struct nlattr *head, int len, int maxtype,
 242                  const struct nla_policy *policy);
 243 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 244               int len, const struct nla_policy *policy);
 245 int nla_policy_len(const struct nla_policy *, int);
 246 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 247 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 248 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 249 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 250 int nla_strcmp(const struct nlattr *nla, const char *str);
 251 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 252 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 253                                    int attrlen, int padattr);
 254 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 255 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 256 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 257                                  int attrlen, int padattr);
 258 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 259 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 260                const void *data);
 261 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 262                      const void *data, int padattr);
 263 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 264 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 265 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 266                   const void *data, int padattr);
 267 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 268 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 269
 270 /**************************************************************************
 271  * Netlink Messages
 272  **************************************************************************/
 273
 274 /**
 275  * nlmsg_msg_size - length of netlink message not including padding
 276  * @payload: length of message payload
 277  */
 278 static inline int nlmsg_msg_size(int payload)
 279 {
 280         return NLMSG_HDRLEN + payload;
 281 }
 282
 283 /**
 284  * nlmsg_total_size - length of netlink message including padding
 285  * @payload: length of message payload
 286  */
 287 static inline int nlmsg_total_size(int payload)
 288 {
 289         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 290 }
 291
 292 /**
 293  * nlmsg_padlen - length of padding at the message's tail
 294  * @payload: length of message payload
 295  */
 296 static inline int nlmsg_padlen(int payload)
 297 {
 298         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 299 }
 300
 301 /**
 302  * nlmsg_data - head of message payload
 303  * @nlh: netlink message header
 304  */
 305 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 306 {
 307         return (unsigned char *) nlh + NLMSG_HDRLEN;
 308 }
 309
 310 /**
 311  * nlmsg_len - length of message payload
 312  * @nlh: netlink message header
 313  */
 314 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 315 {
 316         return nlh->nlmsg_len - NLMSG_HDRLEN;
 317 }
 318
 319 /**
 320  * nlmsg_attrdata - head of attributes data
 321  * @nlh: netlink message header
 322  * @hdrlen: length of family specific header
 323  */
 324 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 325                                             int hdrlen)
 326 {
 327         unsigned char *data = nlmsg_data(nlh);
 328         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 329 }
 330
 331 /**
 332  * nlmsg_attrlen - length of attributes data
 333  * @nlh: netlink message header
 334  * @hdrlen: length of family specific header
 335  */
 336 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 337 {
 338         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 339 }
 340
 341 /**
 342  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 343  * @nlh: netlink message header
 344  * @remaining: number of bytes remaining in message stream
 345  */
 346 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 347 {
 348         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 349                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 350                 nlh->nlmsg_len <= remaining);
 351 }
 352
 353 /**
 354  * nlmsg_next - next netlink message in message stream
 355  * @nlh: netlink message header
 356  * @remaining: number of bytes remaining in message stream
 357  *
 358  * Returns the next netlink message in the message stream and
 359  * decrements remaining by the size of the current message.
 360  */
 361 static inline struct nlmsghdr *
 362 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 363 {
 364         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 365
 366         *remaining -= totlen;
 367
 368         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 369 }
 370
 371 /**
 372  * nlmsg_parse - parse attributes of a netlink message
 373  * @nlh: netlink message header
 374  * @hdrlen: length of family specific header
 375  * @tb: destination array with maxtype+1 elements
 376  * @maxtype: maximum attribute type to be expected
 377  * @policy: validation policy
 378  *
 379  * See nla_parse()
 380  */
 381 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 382                               struct nlattr *tb[], int maxtype,
 383                               const struct nla_policy *policy)
 384 {
 385         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 386                 return -EINVAL;
 387
 388         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 389                          nlmsg_attrlen(nlh, hdrlen), policy);
 390 }
 391
 392 /**
 393  * nlmsg_find_attr - find a specific attribute in a netlink message
 394  * @nlh: netlink message header
 395  * @hdrlen: length of familiy specific header
 396  * @attrtype: type of attribute to look for
 397  *
 398  * Returns the first attribute which matches the specified type.
 399  */
 400 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 401                                              int hdrlen, int attrtype)
 402 {
 403         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 404                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 405 }
 406
 407 /**
 408  * nlmsg_validate - validate a netlink message including attributes
 409  * @nlh: netlinket message header
 410  * @hdrlen: length of familiy specific header
 411  * @maxtype: maximum attribute type to be expected
 412  * @policy: validation policy
 413  */
 414 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 415                                  int hdrlen, int maxtype,
 416                                  const struct nla_policy *policy)
 417 {
 418         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 419                 return -EINVAL;
 420
 421         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 422                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 423 }
 424
 425 /**
 426  * nlmsg_report - need to report back to application?
 427  * @nlh: netlink message header
 428  *
 429  * Returns 1 if a report back to the application is requested.
 430  */
 431 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 432 {
 433         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 434 }
 435
 436 /**
 437  * nlmsg_for_each_attr - iterate over a stream of attributes
 438  * @pos: loop counter, set to current attribute
 439  * @nlh: netlink message header
 440  * @hdrlen: length of familiy specific header
 441  * @rem: initialized to len, holds bytes currently remaining in stream
 442  */
 443 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 444         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 445                           nlmsg_attrlen(nlh, hdrlen), rem)
 446
 447 /**
 448  * nlmsg_put - Add a new netlink message to an skb
 449  * @skb: socket buffer to store message in
 450  * @portid: netlink PORTID of requesting application
 451  * @seq: sequence number of message
 452  * @type: message type
 453  * @payload: length of message payload
 454  * @flags: message flags
 455  *
 456  * Returns NULL if the tailroom of the skb is insufficient to store
 457  * the message header and payload.
 458  */
 459 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 460                                          int type, int payload, int flags)
 461 {
 462         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 463                 return NULL;
 464
 465         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 466 }
 467
 468 /**
 469  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 470  * @skb: socket buffer to store message in
 471  * @cb: netlink callback
 472  * @type: message type
 473  * @payload: length of message payload
 474  * @flags: message flags
 475  *
 476  * Returns NULL if the tailroom of the skb is insufficient to store
 477  * the message header and payload.
 478  */
 479 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 480                                                 struct netlink_callback *cb,
 481                                                 int type, int payload,
 482                                                 int flags)
 483 {
 484         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 485                          type, payload, flags);
 486 }
 487
 488 /**
 489  * nlmsg_new - Allocate a new netlink message
 490  * @payload: size of the message payload
 491  * @flags: the type of memory to allocate.
 492  *
 493  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 494  * and a good default is needed.
 495  */
 496 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 497 {
 498         return alloc_skb(nlmsg_total_size(payload), flags);
 499 }
 500
 501 /**
 502  * nlmsg_end - Finalize a netlink message
 503  * @skb: socket buffer the message is stored in
 504  * @nlh: netlink message header
 505  *
 506  * Corrects the netlink message header to include the appeneded
 507  * attributes. Only necessary if attributes have been added to
 508  * the message.
 509  */
 510 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 511 {
 512         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 513 }
 514
 515 /**
 516  * nlmsg_get_pos - return current position in netlink message
 517  * @skb: socket buffer the message is stored in
 518  *
 519  * Returns a pointer to the current tail of the message.
 520  */
 521 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 522 {
 523         return skb_tail_pointer(skb);
 524 }
 525
 526 /**
 527  * nlmsg_trim - Trim message to a mark
 528  * @skb: socket buffer the message is stored in
 529  * @mark: mark to trim to
 530  *
 531  * Trims the message to the provided mark.
 532  */
 533 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 534 {
 535         if (mark) {
 536                 WARN_ON((unsigned char *) mark < skb->data);
 537                 skb_trim(skb, (unsigned char *) mark - skb->data);
 538         }
 539 }
 540
 541 /**
 542  * nlmsg_cancel - Cancel construction of a netlink message
 543  * @skb: socket buffer the message is stored in
 544  * @nlh: netlink message header
 545  *
 546  * Removes the complete netlink message including all
 547  * attributes from the socket buffer again.
 548  */
 549 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 550 {
 551         nlmsg_trim(skb, nlh);
 552 }
 553
 554 /**
 555  * nlmsg_free - free a netlink message
 556  * @skb: socket buffer of netlink message
 557  */
 558 static inline void nlmsg_free(struct sk_buff *skb)
 559 {
 560         kfree_skb(skb);
 561 }
 562
 563 /**
 564  * nlmsg_multicast - multicast a netlink message
 565  * @sk: netlink socket to spread messages to
 566  * @skb: netlink message as socket buffer
 567  * @portid: own netlink portid to avoid sending to yourself
 568  * @group: multicast group id
 569  * @flags: allocation flags
 570  */
 571 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 572                                   u32 portid, unsigned int group, gfp_t flags)
 573 {
 574         int err;
 575
 576         NETLINK_CB(skb).dst_group = group;
 577
 578         err = netlink_broadcast(sk, skb, portid, group, flags);
 579         if (err > 0)
 580                 err = 0;
 581
 582         return err;
 583 }
 584
 585 /**
 586  * nlmsg_unicast - unicast a netlink message
 587  * @sk: netlink socket to spread message to
 588  * @skb: netlink message as socket buffer
 589  * @portid: netlink portid of the destination socket
 590  */
 591 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 592 {
 593         int err;
 594
 595         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 596         if (err > 0)
 597                 err = 0;
 598
 599         return err;
 600 }
 601
 602 /**
 603  * nlmsg_for_each_msg - iterate over a stream of messages
 604  * @pos: loop counter, set to current message
 605  * @head: head of message stream
 606  * @len: length of message stream
 607  * @rem: initialized to len, holds bytes currently remaining in stream
 608  */
 609 #define nlmsg_for_each_msg(pos, head, len, rem) \
 610         for (pos = head, rem = len; \
 611              nlmsg_ok(pos, rem); \
 612              pos = nlmsg_next(pos, &(rem)))
 613
 614 /**
 615  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 616  * @cb: netlink callback structure that stores the sequence number
 617  * @nlh: netlink message header to write the flag to
 618  *
 619  * This function checks if the sequence (generation) number changed during dump
 620  * and if it did, advertises it in the netlink message header.
 621  *
 622  * The correct way to use it is to set cb->seq to the generation counter when
 623  * all locks for dumping have been acquired, and then call this function for
 624  * each message that is generated.
 625  *
 626  * Note that due to initialisation concerns, 0 is an invalid sequence number
 627  * and must not be used by code that uses this functionality.
 628  */
 629 static inline void
 630 nl_dump_check_consistent(struct netlink_callback *cb,
 631                          struct nlmsghdr *nlh)
 632 {
 633         if (cb->prev_seq && cb->seq != cb->prev_seq)
 634                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 635         cb->prev_seq = cb->seq;
 636 }
 637
 638 /**************************************************************************
 639  * Netlink Attributes
 640  **************************************************************************/
 641
 642 /**
 643  * nla_attr_size - length of attribute not including padding
 644  * @payload: length of payload
 645  */
 646 static inline int nla_attr_size(int payload)
 647 {
 648         return NLA_HDRLEN + payload;
 649 }
 650
 651 /**
 652  * nla_total_size - total length of attribute including padding
 653  * @payload: length of payload
 654  */
 655 static inline int nla_total_size(int payload)
 656 {
 657         return NLA_ALIGN(nla_attr_size(payload));
 658 }
 659
 660 /**
 661  * nla_padlen - length of padding at the tail of attribute
 662  * @payload: length of payload
 663  */
 664 static inline int nla_padlen(int payload)
 665 {
 666         return nla_total_size(payload) - nla_attr_size(payload);
 667 }
 668
 669 /**
 670  * nla_type - attribute type
 671  * @nla: netlink attribute
 672  */
 673 static inline int nla_type(const struct nlattr *nla)
 674 {
 675         return nla->nla_type & NLA_TYPE_MASK;
 676 }
 677
 678 /**
 679  * nla_data - head of payload
 680  * @nla: netlink attribute
 681  */
 682 static inline void *nla_data(const struct nlattr *nla)
 683 {
 684         return (char *) nla + NLA_HDRLEN;
 685 }
 686
 687 /**
 688  * nla_len - length of payload
 689  * @nla: netlink attribute
 690  */
 691 static inline int nla_len(const struct nlattr *nla)
 692 {
 693         return nla->nla_len - NLA_HDRLEN;
 694 }
 695
 696 /**
 697  * nla_ok - check if the netlink attribute fits into the remaining bytes
 698  * @nla: netlink attribute
 699  * @remaining: number of bytes remaining in attribute stream
 700  */
 701 static inline int nla_ok(const struct nlattr *nla, int remaining)
 702 {
 703         return remaining >= (int) sizeof(*nla) &&
 704                nla->nla_len >= sizeof(*nla) &&
 705                nla->nla_len <= remaining;
 706 }
 707
 708 /**
 709  * nla_next - next netlink attribute in attribute stream
 710  * @nla: netlink attribute
 711  * @remaining: number of bytes remaining in attribute stream
 712  *
 713  * Returns the next netlink attribute in the attribute stream and
 714  * decrements remaining by the size of the current attribute.
 715  */
 716 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 717 {
 718         unsigned int totlen = NLA_ALIGN(nla->nla_len);
 719
 720         *remaining -= totlen;
 721         return (struct nlattr *) ((char *) nla + totlen);
 722 }
 723
 724 /**
 725  * nla_find_nested - find attribute in a set of nested attributes
 726  * @nla: attribute containing the nested attributes
 727  * @attrtype: type of attribute to look for
 728  *
 729  * Returns the first attribute which matches the specified type.
 730  */
 731 static inline struct nlattr *
 732 nla_find_nested(const struct nlattr *nla, int attrtype)
 733 {
 734         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 735 }
 736
 737 /**
 738  * nla_parse_nested - parse nested attributes
 739  * @tb: destination array with maxtype+1 elements
 740  * @maxtype: maximum attribute type to be expected
 741  * @nla: attribute containing the nested attributes
 742  * @policy: validation policy
 743  *
 744  * See nla_parse()
 745  */
 746 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 747                                    const struct nlattr *nla,
 748                                    const struct nla_policy *policy)
 749 {
 750         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 751 }
 752
 753 /**
 754  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 755  * @skb: socket buffer to add attribute to
 756  * @attrtype: attribute type
 757  * @value: numeric value
 758  */
 759 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 760 {
 761         return nla_put(skb, attrtype, sizeof(u8), &value);
 762 }
 763
 764 /**
 765  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 766  * @skb: socket buffer to add attribute to
 767  * @attrtype: attribute type
 768  * @value: numeric value
 769  */
 770 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 771 {
 772         return nla_put(skb, attrtype, sizeof(u16), &value);
 773 }
 774
 775 /**
 776  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 777  * @skb: socket buffer to add attribute to
 778  * @attrtype: attribute type
 779  * @value: numeric value
 780  */
 781 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 782 {
 783         return nla_put(skb, attrtype, sizeof(__be16), &value);
 784 }
 785
 786 /**
 787  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 788  * @skb: socket buffer to add attribute to
 789  * @attrtype: attribute type
 790  * @value: numeric value
 791  */
 792 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 793 {
 794         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 795 }
 796
 797 /**
 798  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 799  * @skb: socket buffer to add attribute to
 800  * @attrtype: attribute type
 801  * @value: numeric value
 802  */
 803 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 804 {
 805         return nla_put(skb, attrtype, sizeof(__le16), &value);
 806 }
 807
 808 /**
 809  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 810  * @skb: socket buffer to add attribute to
 811  * @attrtype: attribute type
 812  * @value: numeric value
 813  */
 814 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 815 {
 816         return nla_put(skb, attrtype, sizeof(u32), &value);
 817 }
 818
 819 /**
 820  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 821  * @skb: socket buffer to add attribute to
 822  * @attrtype: attribute type
 823  * @value: numeric value
 824  */
 825 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 826 {
 827         return nla_put(skb, attrtype, sizeof(__be32), &value);
 828 }
 829
 830 /**
 831  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 832  * @skb: socket buffer to add attribute to
 833  * @attrtype: attribute type
 834  * @value: numeric value
 835  */
 836 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 837 {
 838         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 839 }
 840
 841 /**
 842  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 843  * @skb: socket buffer to add attribute to
 844  * @attrtype: attribute type
 845  * @value: numeric value
 846  */
 847 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 848 {
 849         return nla_put(skb, attrtype, sizeof(__le32), &value);
 850 }
 851
 852 /**
 853  * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
 854  * @skb: socket buffer to add attribute to
 855  * @attrtype: attribute type
 856  * @value: numeric value
 857  * @padattr: attribute type for the padding
 858  */
 859 static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
 860                                     u64 value, int padattr)
 861 {
 862         return nla_put_64bit(skb, attrtype, sizeof(u64), &value, padattr);
 863 }
 864
 865 /**
 866  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 867  * @skb: socket buffer to add attribute to
 868  * @attrtype: attribute type
 869  * @value: numeric value
 870  * @padattr: attribute type for the padding
 871  */
 872 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
 873                                int padattr)
 874 {
 875         return nla_put_64bit(skb, attrtype, sizeof(__be64), &value, padattr);
 876 }
 877
 878 /**
 879  * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
 880  * @skb: socket buffer to add attribute to
 881  * @attrtype: attribute type
 882  * @value: numeric value
 883  * @padattr: attribute type for the padding
 884  */
 885 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
 886                                 int padattr)
 887 {
 888         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value,
 889                             padattr);
 890 }
 891
 892 /**
 893  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 894  * @skb: socket buffer to add attribute to
 895  * @attrtype: attribute type
 896  * @value: numeric value
 897  * @padattr: attribute type for the padding
 898  */
 899 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
 900                                int padattr)
 901 {
 902         return nla_put_64bit(skb, attrtype, sizeof(__le64), &value, padattr);
 903 }
 904
 905 /**
 906  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 907  * @skb: socket buffer to add attribute to
 908  * @attrtype: attribute type
 909  * @value: numeric value
 910  */
 911 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 912 {
 913         return nla_put(skb, attrtype, sizeof(s8), &value);
 914 }
 915
 916 /**
 917  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 918  * @skb: socket buffer to add attribute to
 919  * @attrtype: attribute type
 920  * @value: numeric value
 921  */
 922 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 923 {
 924         return nla_put(skb, attrtype, sizeof(s16), &value);
 925 }
 926
 927 /**
 928  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 929  * @skb: socket buffer to add attribute to
 930  * @attrtype: attribute type
 931  * @value: numeric value
 932  */
 933 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 934 {
 935         return nla_put(skb, attrtype, sizeof(s32), &value);
 936 }
 937
 938 /**
 939  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 940  * @skb: socket buffer to add attribute to
 941  * @attrtype: attribute type
 942  * @value: numeric value
 943  * @padattr: attribute type for the padding
 944  */
 945 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
 946                               int padattr)
 947 {
 948         return nla_put_64bit(skb, attrtype, sizeof(s64), &value, padattr);
 949 }
 950
 951 /**
 952  * nla_put_string - Add a string netlink attribute to a socket buffer
 953  * @skb: socket buffer to add attribute to
 954  * @attrtype: attribute type
 955  * @str: NUL terminated string
 956  */
 957 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 958                                  const char *str)
 959 {
 960         return nla_put(skb, attrtype, strlen(str) + 1, str);
 961 }
 962
 963 /**
 964  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 965  * @skb: socket buffer to add attribute to
 966  * @attrtype: attribute type
 967  */
 968 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 969 {
 970         return nla_put(skb, attrtype, 0, NULL);
 971 }
 972
 973 /**
 974  * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
 975  * @skb: socket buffer to add attribute to
 976  * @attrtype: attribute type
 977  * @njiffies: number of jiffies to convert to msecs
 978  * @padattr: attribute type for the padding
 979  */
 980 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 981                                 unsigned long njiffies, int padattr)
 982 {
 983         u64 tmp = jiffies_to_msecs(njiffies);
 984
 985         return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
 986 }
 987
 988 /**
 989  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 990  * buffer
 991  * @skb: socket buffer to add attribute to
 992  * @attrtype: attribute type
 993  * @addr: IPv4 address
 994  */
 995 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
 996                                   __be32 addr)
 997 {
 998         return nla_put_be32(skb, attrtype, addr);
 999 }
1000
1001 /**
1002  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
1003  * buffer
1004  * @skb: socket buffer to add attribute to
1005  * @attrtype: attribute type
1006  * @addr: IPv6 address
1007  */
1008 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
1009                                    const struct in6_addr *addr)
1010 {
1011         return nla_put(skb, attrtype, sizeof(*addr), addr);
1012 }
1013
1014 /**
1015  * nla_get_u32 - return payload of u32 attribute
1016  * @nla: u32 netlink attribute
1017  */
1018 static inline u32 nla_get_u32(const struct nlattr *nla)
1019 {
1020         return *(u32 *) nla_data(nla);
1021 }
1022
1023 /**
1024  * nla_get_be32 - return payload of __be32 attribute
1025  * @nla: __be32 netlink attribute
1026  */
1027 static inline __be32 nla_get_be32(const struct nlattr *nla)
1028 {
1029         return *(__be32 *) nla_data(nla);
1030 }
1031
1032 /**
1033  * nla_get_le32 - return payload of __le32 attribute
1034  * @nla: __le32 netlink attribute
1035  */
1036 static inline __le32 nla_get_le32(const struct nlattr *nla)
1037 {
1038         return *(__le32 *) nla_data(nla);
1039 }
1040
1041 /**
1042  * nla_get_u16 - return payload of u16 attribute
1043  * @nla: u16 netlink attribute
1044  */
1045 static inline u16 nla_get_u16(const struct nlattr *nla)
1046 {
1047         return *(u16 *) nla_data(nla);
1048 }
1049
1050 /**
1051  * nla_get_be16 - return payload of __be16 attribute
1052  * @nla: __be16 netlink attribute
1053  */
1054 static inline __be16 nla_get_be16(const struct nlattr *nla)
1055 {
1056         return *(__be16 *) nla_data(nla);
1057 }
1058
1059 /**
1060  * nla_get_le16 - return payload of __le16 attribute
1061  * @nla: __le16 netlink attribute
1062  */
1063 static inline __le16 nla_get_le16(const struct nlattr *nla)
1064 {
1065         return *(__le16 *) nla_data(nla);
1066 }
1067
1068 /**
1069  * nla_get_u8 - return payload of u8 attribute
1070  * @nla: u8 netlink attribute
1071  */
1072 static inline u8 nla_get_u8(const struct nlattr *nla)
1073 {
1074         return *(u8 *) nla_data(nla);
1075 }
1076
1077 /**
1078  * nla_get_u64 - return payload of u64 attribute
1079  * @nla: u64 netlink attribute
1080  */
1081 static inline u64 nla_get_u64(const struct nlattr *nla)
1082 {
1083         u64 tmp;
1084
1085         nla_memcpy(&tmp, nla, sizeof(tmp));
1086
1087         return tmp;
1088 }
1089
1090 /**
1091  * nla_get_be64 - return payload of __be64 attribute
1092  * @nla: __be64 netlink attribute
1093  */
1094 static inline __be64 nla_get_be64(const struct nlattr *nla)
1095 {
1096         __be64 tmp;
1097
1098         nla_memcpy(&tmp, nla, sizeof(tmp));
1099
1100         return tmp;
1101 }
1102
1103 /**
1104  * nla_get_le64 - return payload of __le64 attribute
1105  * @nla: __le64 netlink attribute
1106  */
1107 static inline __le64 nla_get_le64(const struct nlattr *nla)
1108 {
1109         return *(__le64 *) nla_data(nla);
1110 }
1111
1112 /**
1113  * nla_get_s32 - return payload of s32 attribute
1114  * @nla: s32 netlink attribute
1115  */
1116 static inline s32 nla_get_s32(const struct nlattr *nla)
1117 {
1118         return *(s32 *) nla_data(nla);
1119 }
1120
1121 /**
1122  * nla_get_s16 - return payload of s16 attribute
1123  * @nla: s16 netlink attribute
1124  */
1125 static inline s16 nla_get_s16(const struct nlattr *nla)
1126 {
1127         return *(s16 *) nla_data(nla);
1128 }
1129
1130 /**
1131  * nla_get_s8 - return payload of s8 attribute
1132  * @nla: s8 netlink attribute
1133  */
1134 static inline s8 nla_get_s8(const struct nlattr *nla)
1135 {
1136         return *(s8 *) nla_data(nla);
1137 }
1138
1139 /**
1140  * nla_get_s64 - return payload of s64 attribute
1141  * @nla: s64 netlink attribute
1142  */
1143 static inline s64 nla_get_s64(const struct nlattr *nla)
1144 {
1145         s64 tmp;
1146
1147         nla_memcpy(&tmp, nla, sizeof(tmp));
1148
1149         return tmp;
1150 }
1151
1152 /**
1153  * nla_get_flag - return payload of flag attribute
1154  * @nla: flag netlink attribute
1155  */
1156 static inline int nla_get_flag(const struct nlattr *nla)
1157 {
1158         return !!nla;
1159 }
1160
1161 /**
1162  * nla_get_msecs - return payload of msecs attribute
1163  * @nla: msecs netlink attribute
1164  *
1165  * Returns the number of milliseconds in jiffies.
1166  */
1167 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1168 {
1169         u64 msecs = nla_get_u64(nla);
1170
1171         return msecs_to_jiffies((unsigned long) msecs);
1172 }
1173
1174 /**
1175  * nla_get_in_addr - return payload of IPv4 address attribute
1176  * @nla: IPv4 address netlink attribute
1177  */
1178 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1179 {
1180         return *(__be32 *) nla_data(nla);
1181 }
1182
1183 /**
1184  * nla_get_in6_addr - return payload of IPv6 address attribute
1185  * @nla: IPv6 address netlink attribute
1186  */
1187 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1188 {
1189         struct in6_addr tmp;
1190
1191         nla_memcpy(&tmp, nla, sizeof(tmp));
1192         return tmp;
1193 }
1194
1195 /**
1196  * nla_memdup - duplicate attribute memory (kmemdup)
1197  * @src: netlink attribute to duplicate from
1198  * @gfp: GFP mask
1199  */
1200 static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
1201 {
1202         return kmemdup(nla_data(src), nla_len(src), gfp);
1203 }
1204
1205 /**
1206  * nla_nest_start - Start a new level of nested attributes
1207  * @skb: socket buffer to add attributes to
1208  * @attrtype: attribute type of container
1209  *
1210  * Returns the container attribute
1211  */
1212 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1213 {
1214         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1215
1216         if (nla_put(skb, attrtype, 0, NULL) < 0)
1217                 return NULL;
1218
1219         return start;
1220 }
1221
1222 /**
1223  * nla_nest_end - Finalize nesting of attributes
1224  * @skb: socket buffer the attributes are stored in
1225  * @start: container attribute
1226  *
1227  * Corrects the container attribute header to include the all
1228  * appeneded attributes.
1229  *
1230  * Returns the total data length of the skb.
1231  */
1232 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1233 {
1234         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1235         return skb->len;
1236 }
1237
1238 /**
1239  * nla_nest_cancel - Cancel nesting of attributes
1240  * @skb: socket buffer the message is stored in
1241  * @start: container attribute
1242  *
1243  * Removes the container attribute and including all nested
1244  * attributes. Returns -EMSGSIZE
1245  */
1246 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1247 {
1248         nlmsg_trim(skb, start);
1249 }
1250
1251 /**
1252  * nla_validate_nested - Validate a stream of nested attributes
1253  * @start: container attribute
1254  * @maxtype: maximum attribute type to be expected
1255  * @policy: validation policy
1256  *
1257  * Validates all attributes in the nested attribute stream against the
1258  * specified policy. Attributes with a type exceeding maxtype will be
1259  * ignored. See documenation of struct nla_policy for more details.
1260  *
1261  * Returns 0 on success or a negative error code.
1262  */
1263 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1264                                       const struct nla_policy *policy)
1265 {
1266         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1267 }
1268
1269 /**
1270  * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
1271  * @skb: socket buffer the message is stored in
1272  *
1273  * Return true if padding is needed to align the next attribute (nla_data()) to
1274  * a 64-bit aligned area.
1275  */
1276 static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
1277 {
1278 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1279         /* The nlattr header is 4 bytes in size, that's why we test
1280          * if the skb->data _is_ aligned.  A NOP attribute, plus
1281          * nlattr header for next attribute, will make nla_data()
1282          * 8-byte aligned.
1283          */
1284         if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
1285                 return true;
1286 #endif
1287         return false;
1288 }
1289
1290 /**
1291  * nla_align_64bit - 64-bit align the nla_data() of next attribute
1292  * @skb: socket buffer the message is stored in
1293  * @padattr: attribute type for the padding
1294  *
1295  * Conditionally emit a padding netlink attribute in order to make
1296  * the next attribute we emit have a 64-bit aligned nla_data() area.
1297  * This will only be done in architectures which do not have
1298  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
1299  *
1300  * Returns zero on success or a negative error code.
1301  */
1302 static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
1303 {
1304         if (nla_need_padding_for_64bit(skb) &&
1305             !nla_reserve(skb, padattr, 0))
1306                 return -EMSGSIZE;
1307
1308         return 0;
1309 }
1310
1311 /**
1312  * nla_total_size_64bit - total length of attribute including padding
1313  * @payload: length of payload
1314  */
1315 static inline int nla_total_size_64bit(int payload)
1316 {
1317         return NLA_ALIGN(nla_attr_size(payload))
1318 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
1319                 + NLA_ALIGN(nla_attr_size(0))
1320 #endif
1321                 ;
1322 }
1323
1324 /**
1325  * nla_for_each_attr - iterate over a stream of attributes
1326  * @pos: loop counter, set to current attribute
1327  * @head: head of attribute stream
1328  * @len: length of attribute stream
1329  * @rem: initialized to len, holds bytes currently remaining in stream
1330  */
1331 #define nla_for_each_attr(pos, head, len, rem) \
1332         for (pos = head, rem = len; \
1333              nla_ok(pos, rem); \
1334              pos = nla_next(pos, &(rem)))
1335
1336 /**
1337  * nla_for_each_nested - iterate over nested attributes
1338  * @pos: loop counter, set to current attribute
1339  * @nla: attribute containing the nested attributes
1340  * @rem: initialized to len, holds bytes currently remaining in stream
1341  */
1342 #define nla_for_each_nested(pos, nla, rem) \
1343         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1344
1345 /**
1346  * nla_is_last - Test if attribute is last in stream
1347  * @nla: attribute to test
1348  * @rem: bytes remaining in stream
1349  */
1350 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1351 {
1352         return nla->nla_len == rem;
1353 }
1354
1355 #endif