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
   8 /* ========================================================================
   9  *         Netlink Messages and Attributes Interface (As Seen On TV)
  10  * ------------------------------------------------------------------------
  11  *                          Messages Interface
  12  * ------------------------------------------------------------------------
  13  *
  14  * Message Format:
  15  *    <--- nlmsg_total_size(payload)  --->
  16  *    <-- nlmsg_msg_size(payload) ->
  17  *   +----------+- - -+-------------+- - -+-------- - -
  18  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  19  *   +----------+- - -+-------------+- - -+-------- - -
  20  *   nlmsg_data(nlh)---^                   ^
  21  *   nlmsg_next(nlh)-----------------------+
  22  *
  23  * Payload Format:
  24  *    <---------------------- nlmsg_len(nlh) --------------------->
  25  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  26  *   +----------------------+- - -+--------------------------------+
  27  *   |     Family Header    | Pad |           Attributes           |
  28  *   +----------------------+- - -+--------------------------------+
  29  *   nlmsg_attrdata(nlh, hdrlen)---^
  30  *
  31  * Data Structures:
  32  *   struct nlmsghdr                    netlink message header
  33  *
  34  * Message Construction:
  35  *   nlmsg_new()                        create a new netlink message
  36  *   nlmsg_put()                        add a netlink message to an skb
  37  *   nlmsg_put_answer()                 callback based nlmsg_put()
  38  *   nlmsg_end()                        finalize netlink message
  39  *   nlmsg_get_pos()                    return current position in message
  40  *   nlmsg_trim()                       trim part of message
  41  *   nlmsg_cancel()                     cancel message construction
  42  *   nlmsg_free()                       free a netlink message
  43  *
  44  * Message Sending:
  45  *   nlmsg_multicast()                  multicast message to several groups
  46  *   nlmsg_unicast()                    unicast a message to a single socket
  47  *   nlmsg_notify()                     send notification message
  48  *
  49  * Message Length Calculations:
  50  *   nlmsg_msg_size(payload)            length of message w/o padding
  51  *   nlmsg_total_size(payload)          length of message w/ padding
  52  *   nlmsg_padlen(payload)              length of padding at tail
  53  *
  54  * Message Payload Access:
  55  *   nlmsg_data(nlh)                    head of message payload
  56  *   nlmsg_len(nlh)                     length of message payload
  57  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  58  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  59  *
  60  * Message Parsing:
  61  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  62  *   nlmsg_next(nlh, remaining)         get next netlink message
  63  *   nlmsg_parse()                      parse attributes of a message
  64  *   nlmsg_find_attr()                  find an attribute in a message
  65  *   nlmsg_for_each_msg()               loop over all messages
  66  *   nlmsg_validate()                   validate netlink message incl. attrs
  67  *   nlmsg_for_each_attr()              loop over all attributes
  68  *
  69  * Misc:
  70  *   nlmsg_report()                     report back to application?
  71  *
  72  * ------------------------------------------------------------------------
  73  *                          Attributes Interface
  74  * ------------------------------------------------------------------------
  75  *
  76  * Attribute Format:
  77  *    <------- nla_total_size(payload) ------->
  78  *    <---- nla_attr_size(payload) ----->
  79  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  80  *   |  Header  | Pad |     Payload      | Pad |  Header
  81  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  82  *                     <- nla_len(nla) ->      ^
  83  *   nla_data(nla)----^                        |
  84  *   nla_next(nla)-----------------------------'
  85  *
  86  * Data Structures:
  87  *   struct nlattr                      netlink attribute header
  88  *
  89  * Attribute Construction:
  90  *   nla_reserve(skb, type, len)        reserve room for an attribute
  91  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  92  *   nla_put(skb, type, len, data)      add attribute to skb
  93  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  94  *   nla_append(skb, len, data)         append data to skb
  95  *
  96  * Attribute Construction for Basic Types:
  97  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  98  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  99  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
 100  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
 101  *   nla_put_s8(skb, type, value)       add s8 attribute to skb
 102  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
 103  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
 104  *   nla_put_s64(skb, type, value)      add s64 attribute to skb
 105  *   nla_put_string(skb, type, str)     add string attribute to skb
 106  *   nla_put_flag(skb, type)            add flag attribute to skb
 107  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 108  *
 109  * Nested Attributes Construction:
 110  *   nla_nest_start(skb, type)          start a nested attribute
 111  *   nla_nest_end(skb, nla)             finalize a nested attribute
 112  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 113  *
 114  * Attribute Length Calculations:
 115  *   nla_attr_size(payload)             length of attribute w/o padding
 116  *   nla_total_size(payload)            length of attribute w/ padding
 117  *   nla_padlen(payload)                length of padding
 118  *
 119  * Attribute Payload Access:
 120  *   nla_data(nla)                      head of attribute payload
 121  *   nla_len(nla)                       length of attribute payload
 122  *
 123  * Attribute Payload Access for Basic Types:
 124  *   nla_get_u8(nla)                    get payload for a u8 attribute
 125  *   nla_get_u16(nla)                   get payload for a u16 attribute
 126  *   nla_get_u32(nla)                   get payload for a u32 attribute
 127  *   nla_get_u64(nla)                   get payload for a u64 attribute
 128  *   nla_get_s8(nla)                    get payload for a s8 attribute
 129  *   nla_get_s16(nla)                   get payload for a s16 attribute
 130  *   nla_get_s32(nla)                   get payload for a s32 attribute
 131  *   nla_get_s64(nla)                   get payload for a s64 attribute
 132  *   nla_get_flag(nla)                  return 1 if flag is true
 133  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 134  *
 135  * Attribute Misc:
 136  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 137  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 138  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 139  *   nla_strcmp(nla, str)               compare attribute with string
 140  *
 141  * Attribute Parsing:
 142  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 143  *   nla_next(nla, remaining)           get next netlink attribute
 144  *   nla_validate()                     validate a stream of attributes
 145  *   nla_validate_nested()              validate a stream of nested attributes
 146  *   nla_find()                         find attribute in stream of attributes
 147  *   nla_find_nested()                  find attribute in nested attributes
 148  *   nla_parse()                        parse and validate stream of attrs
 149  *   nla_parse_nested()                 parse nested attribuets
 150  *   nla_for_each_attr()                loop over all attributes
 151  *   nla_for_each_nested()              loop over the nested attributes
 152  *=========================================================================
 153  */
 154
 155  /**
 156   * Standard attribute types to specify validation policy
 157   */
 158 enum {
 159         NLA_UNSPEC,
 160         NLA_U8,
 161         NLA_U16,
 162         NLA_U32,
 163         NLA_U64,
 164         NLA_STRING,
 165         NLA_FLAG,
 166         NLA_MSECS,
 167         NLA_NESTED,
 168         NLA_NESTED_COMPAT,
 169         NLA_NUL_STRING,
 170         NLA_BINARY,
 171         NLA_S8,
 172         NLA_S16,
 173         NLA_S32,
 174         NLA_S64,
 175         __NLA_TYPE_MAX,
 176 };
 177
 178 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 179
 180 /**
 181  * struct nla_policy - attribute validation policy
 182  * @type: Type of attribute or NLA_UNSPEC
 183  * @len: Type specific length of payload
 184  *
 185  * Policies are defined as arrays of this struct, the array must be
 186  * accessible by attribute type up to the highest identifier to be expected.
 187  *
 188  * Meaning of `len' field:
 189  *    NLA_STRING           Maximum length of string
 190  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 191  *    NLA_FLAG             Unused
 192  *    NLA_BINARY           Maximum length of attribute payload
 193  *    NLA_NESTED           Don't use `len' field -- length verification is
 194  *                         done by checking len of nested header (or empty)
 195  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 196  *    NLA_U8, NLA_U16,
 197  *    NLA_U32, NLA_U64,
 198  *    NLA_S8, NLA_S16,
 199  *    NLA_S32, NLA_S64,
 200  *    NLA_MSECS            Leaving the length field zero will verify the
 201  *                         given type fits, using it verifies minimum length
 202  *                         just like "All other"
 203  *    All other            Minimum length of attribute payload
 204  *
 205  * Example:
 206  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 207  *      [ATTR_FOO] = { .type = NLA_U16 },
 208  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 209  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 210  * };
 211  */
 212 struct nla_policy {
 213         u16             type;
 214         u16             len;
 215 };
 216
 217 /**
 218  * struct nl_info - netlink source information
 219  * @nlh: Netlink message header of original request
 220  * @portid: Netlink PORTID of requesting application
 221  */
 222 struct nl_info {
 223         struct nlmsghdr         *nlh;
 224         struct net              *nl_net;
 225         u32                     portid;
 226 };
 227
 228 int netlink_rcv_skb(struct sk_buff *skb,
 229                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
 230 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 231                  unsigned int group, int report, gfp_t flags);
 232
 233 int nla_validate(const struct nlattr *head, int len, int maxtype,
 234                  const struct nla_policy *policy);
 235 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 236               int len, const struct nla_policy *policy);
 237 int nla_policy_len(const struct nla_policy *, int);
 238 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 239 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 240 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 241 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 242 int nla_strcmp(const struct nlattr *nla, const char *str);
 243 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 244 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 245 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 246 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 247 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 248                const void *data);
 249 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 250 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 251 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 252 int nla_append(struct sk_buff *skb, int attrlen, const void *data);
 253
 254 /**************************************************************************
 255  * Netlink Messages
 256  **************************************************************************/
 257
 258 /**
 259  * nlmsg_msg_size - length of netlink message not including padding
 260  * @payload: length of message payload
 261  */
 262 static inline int nlmsg_msg_size(int payload)
 263 {
 264         return NLMSG_HDRLEN + payload;
 265 }
 266
 267 /**
 268  * nlmsg_total_size - length of netlink message including padding
 269  * @payload: length of message payload
 270  */
 271 static inline int nlmsg_total_size(int payload)
 272 {
 273         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 274 }
 275
 276 /**
 277  * nlmsg_padlen - length of padding at the message's tail
 278  * @payload: length of message payload
 279  */
 280 static inline int nlmsg_padlen(int payload)
 281 {
 282         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 283 }
 284
 285 /**
 286  * nlmsg_data - head of message payload
 287  * @nlh: netlink message header
 288  */
 289 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 290 {
 291         return (unsigned char *) nlh + NLMSG_HDRLEN;
 292 }
 293
 294 /**
 295  * nlmsg_len - length of message payload
 296  * @nlh: netlink message header
 297  */
 298 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 299 {
 300         return nlh->nlmsg_len - NLMSG_HDRLEN;
 301 }
 302
 303 /**
 304  * nlmsg_attrdata - head of attributes data
 305  * @nlh: netlink message header
 306  * @hdrlen: length of family specific header
 307  */
 308 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 309                                             int hdrlen)
 310 {
 311         unsigned char *data = nlmsg_data(nlh);
 312         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 313 }
 314
 315 /**
 316  * nlmsg_attrlen - length of attributes data
 317  * @nlh: netlink message header
 318  * @hdrlen: length of family specific header
 319  */
 320 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 321 {
 322         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 323 }
 324
 325 /**
 326  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 327  * @nlh: netlink message header
 328  * @remaining: number of bytes remaining in message stream
 329  */
 330 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 331 {
 332         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 333                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 334                 nlh->nlmsg_len <= remaining);
 335 }
 336
 337 /**
 338  * nlmsg_next - next netlink message in message stream
 339  * @nlh: netlink message header
 340  * @remaining: number of bytes remaining in message stream
 341  *
 342  * Returns the next netlink message in the message stream and
 343  * decrements remaining by the size of the current message.
 344  */
 345 static inline struct nlmsghdr *
 346 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 347 {
 348         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 349
 350         *remaining -= totlen;
 351
 352         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 353 }
 354
 355 /**
 356  * nlmsg_parse - parse attributes of a netlink message
 357  * @nlh: netlink message header
 358  * @hdrlen: length of family specific header
 359  * @tb: destination array with maxtype+1 elements
 360  * @maxtype: maximum attribute type to be expected
 361  * @policy: validation policy
 362  *
 363  * See nla_parse()
 364  */
 365 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 366                               struct nlattr *tb[], int maxtype,
 367                               const struct nla_policy *policy)
 368 {
 369         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 370                 return -EINVAL;
 371
 372         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 373                          nlmsg_attrlen(nlh, hdrlen), policy);
 374 }
 375
 376 /**
 377  * nlmsg_find_attr - find a specific attribute in a netlink message
 378  * @nlh: netlink message header
 379  * @hdrlen: length of familiy specific header
 380  * @attrtype: type of attribute to look for
 381  *
 382  * Returns the first attribute which matches the specified type.
 383  */
 384 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 385                                              int hdrlen, int attrtype)
 386 {
 387         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 388                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 389 }
 390
 391 /**
 392  * nlmsg_validate - validate a netlink message including attributes
 393  * @nlh: netlinket message header
 394  * @hdrlen: length of familiy specific header
 395  * @maxtype: maximum attribute type to be expected
 396  * @policy: validation policy
 397  */
 398 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 399                                  int hdrlen, int maxtype,
 400                                  const struct nla_policy *policy)
 401 {
 402         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 403                 return -EINVAL;
 404
 405         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 406                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 407 }
 408
 409 /**
 410  * nlmsg_report - need to report back to application?
 411  * @nlh: netlink message header
 412  *
 413  * Returns 1 if a report back to the application is requested.
 414  */
 415 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 416 {
 417         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 418 }
 419
 420 /**
 421  * nlmsg_for_each_attr - iterate over a stream of attributes
 422  * @pos: loop counter, set to current attribute
 423  * @nlh: netlink message header
 424  * @hdrlen: length of familiy specific header
 425  * @rem: initialized to len, holds bytes currently remaining in stream
 426  */
 427 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 428         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 429                           nlmsg_attrlen(nlh, hdrlen), rem)
 430
 431 /**
 432  * nlmsg_put - Add a new netlink message to an skb
 433  * @skb: socket buffer to store message in
 434  * @portid: netlink PORTID of requesting application
 435  * @seq: sequence number of message
 436  * @type: message type
 437  * @payload: length of message payload
 438  * @flags: message flags
 439  *
 440  * Returns NULL if the tailroom of the skb is insufficient to store
 441  * the message header and payload.
 442  */
 443 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 444                                          int type, int payload, int flags)
 445 {
 446         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 447                 return NULL;
 448
 449         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 450 }
 451
 452 /**
 453  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 454  * @skb: socket buffer to store message in
 455  * @cb: netlink callback
 456  * @type: message type
 457  * @payload: length of message payload
 458  * @flags: message flags
 459  *
 460  * Returns NULL if the tailroom of the skb is insufficient to store
 461  * the message header and payload.
 462  */
 463 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 464                                                 struct netlink_callback *cb,
 465                                                 int type, int payload,
 466                                                 int flags)
 467 {
 468         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 469                          type, payload, flags);
 470 }
 471
 472 /**
 473  * nlmsg_new - Allocate a new netlink message
 474  * @payload: size of the message payload
 475  * @flags: the type of memory to allocate.
 476  *
 477  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 478  * and a good default is needed.
 479  */
 480 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 481 {
 482         return alloc_skb(nlmsg_total_size(payload), flags);
 483 }
 484
 485 /**
 486  * nlmsg_end - Finalize a netlink message
 487  * @skb: socket buffer the message is stored in
 488  * @nlh: netlink message header
 489  *
 490  * Corrects the netlink message header to include the appeneded
 491  * attributes. Only necessary if attributes have been added to
 492  * the message.
 493  */
 494 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 495 {
 496         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 497 }
 498
 499 /**
 500  * nlmsg_get_pos - return current position in netlink message
 501  * @skb: socket buffer the message is stored in
 502  *
 503  * Returns a pointer to the current tail of the message.
 504  */
 505 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 506 {
 507         return skb_tail_pointer(skb);
 508 }
 509
 510 /**
 511  * nlmsg_trim - Trim message to a mark
 512  * @skb: socket buffer the message is stored in
 513  * @mark: mark to trim to
 514  *
 515  * Trims the message to the provided mark.
 516  */
 517 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 518 {
 519         if (mark) {
 520                 WARN_ON((unsigned char *) mark < skb->data);
 521                 skb_trim(skb, (unsigned char *) mark - skb->data);
 522         }
 523 }
 524
 525 /**
 526  * nlmsg_cancel - Cancel construction of a netlink message
 527  * @skb: socket buffer the message is stored in
 528  * @nlh: netlink message header
 529  *
 530  * Removes the complete netlink message including all
 531  * attributes from the socket buffer again.
 532  */
 533 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 534 {
 535         nlmsg_trim(skb, nlh);
 536 }
 537
 538 /**
 539  * nlmsg_free - free a netlink message
 540  * @skb: socket buffer of netlink message
 541  */
 542 static inline void nlmsg_free(struct sk_buff *skb)
 543 {
 544         kfree_skb(skb);
 545 }
 546
 547 /**
 548  * nlmsg_multicast - multicast a netlink message
 549  * @sk: netlink socket to spread messages to
 550  * @skb: netlink message as socket buffer
 551  * @portid: own netlink portid to avoid sending to yourself
 552  * @group: multicast group id
 553  * @flags: allocation flags
 554  */
 555 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 556                                   u32 portid, unsigned int group, gfp_t flags)
 557 {
 558         int err;
 559
 560         NETLINK_CB(skb).dst_group = group;
 561
 562         err = netlink_broadcast(sk, skb, portid, group, flags);
 563         if (err > 0)
 564                 err = 0;
 565
 566         return err;
 567 }
 568
 569 /**
 570  * nlmsg_unicast - unicast a netlink message
 571  * @sk: netlink socket to spread message to
 572  * @skb: netlink message as socket buffer
 573  * @portid: netlink portid of the destination socket
 574  */
 575 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 576 {
 577         int err;
 578
 579         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 580         if (err > 0)
 581                 err = 0;
 582
 583         return err;
 584 }
 585
 586 /**
 587  * nlmsg_for_each_msg - iterate over a stream of messages
 588  * @pos: loop counter, set to current message
 589  * @head: head of message stream
 590  * @len: length of message stream
 591  * @rem: initialized to len, holds bytes currently remaining in stream
 592  */
 593 #define nlmsg_for_each_msg(pos, head, len, rem) \
 594         for (pos = head, rem = len; \
 595              nlmsg_ok(pos, rem); \
 596              pos = nlmsg_next(pos, &(rem)))
 597
 598 /**
 599  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 600  * @cb: netlink callback structure that stores the sequence number
 601  * @nlh: netlink message header to write the flag to
 602  *
 603  * This function checks if the sequence (generation) number changed during dump
 604  * and if it did, advertises it in the netlink message header.
 605  *
 606  * The correct way to use it is to set cb->seq to the generation counter when
 607  * all locks for dumping have been acquired, and then call this function for
 608  * each message that is generated.
 609  *
 610  * Note that due to initialisation concerns, 0 is an invalid sequence number
 611  * and must not be used by code that uses this functionality.
 612  */
 613 static inline void
 614 nl_dump_check_consistent(struct netlink_callback *cb,
 615                          struct nlmsghdr *nlh)
 616 {
 617         if (cb->prev_seq && cb->seq != cb->prev_seq)
 618                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 619         cb->prev_seq = cb->seq;
 620 }
 621
 622 /**************************************************************************
 623  * Netlink Attributes
 624  **************************************************************************/
 625
 626 /**
 627  * nla_attr_size - length of attribute not including padding
 628  * @payload: length of payload
 629  */
 630 static inline int nla_attr_size(int payload)
 631 {
 632         return NLA_HDRLEN + payload;
 633 }
 634
 635 /**
 636  * nla_total_size - total length of attribute including padding
 637  * @payload: length of payload
 638  */
 639 static inline int nla_total_size(int payload)
 640 {
 641         return NLA_ALIGN(nla_attr_size(payload));
 642 }
 643
 644 /**
 645  * nla_padlen - length of padding at the tail of attribute
 646  * @payload: length of payload
 647  */
 648 static inline int nla_padlen(int payload)
 649 {
 650         return nla_total_size(payload) - nla_attr_size(payload);
 651 }
 652
 653 /**
 654  * nla_type - attribute type
 655  * @nla: netlink attribute
 656  */
 657 static inline int nla_type(const struct nlattr *nla)
 658 {
 659         return nla->nla_type & NLA_TYPE_MASK;
 660 }
 661
 662 /**
 663  * nla_data - head of payload
 664  * @nla: netlink attribute
 665  */
 666 static inline void *nla_data(const struct nlattr *nla)
 667 {
 668         return (char *) nla + NLA_HDRLEN;
 669 }
 670
 671 /**
 672  * nla_len - length of payload
 673  * @nla: netlink attribute
 674  */
 675 static inline int nla_len(const struct nlattr *nla)
 676 {
 677         return nla->nla_len - NLA_HDRLEN;
 678 }
 679
 680 /**
 681  * nla_ok - check if the netlink attribute fits into the remaining bytes
 682  * @nla: netlink attribute
 683  * @remaining: number of bytes remaining in attribute stream
 684  */
 685 static inline int nla_ok(const struct nlattr *nla, int remaining)
 686 {
 687         return remaining >= (int) sizeof(*nla) &&
 688                nla->nla_len >= sizeof(*nla) &&
 689                nla->nla_len <= remaining;
 690 }
 691
 692 /**
 693  * nla_next - next netlink attribute in attribute stream
 694  * @nla: netlink attribute
 695  * @remaining: number of bytes remaining in attribute stream
 696  *
 697  * Returns the next netlink attribute in the attribute stream and
 698  * decrements remaining by the size of the current attribute.
 699  */
 700 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 701 {
 702         int totlen = NLA_ALIGN(nla->nla_len);
 703
 704         *remaining -= totlen;
 705         return (struct nlattr *) ((char *) nla + totlen);
 706 }
 707
 708 /**
 709  * nla_find_nested - find attribute in a set of nested attributes
 710  * @nla: attribute containing the nested attributes
 711  * @attrtype: type of attribute to look for
 712  *
 713  * Returns the first attribute which matches the specified type.
 714  */
 715 static inline struct nlattr *
 716 nla_find_nested(const struct nlattr *nla, int attrtype)
 717 {
 718         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 719 }
 720
 721 /**
 722  * nla_parse_nested - parse nested attributes
 723  * @tb: destination array with maxtype+1 elements
 724  * @maxtype: maximum attribute type to be expected
 725  * @nla: attribute containing the nested attributes
 726  * @policy: validation policy
 727  *
 728  * See nla_parse()
 729  */
 730 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 731                                    const struct nlattr *nla,
 732                                    const struct nla_policy *policy)
 733 {
 734         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 735 }
 736
 737 /**
 738  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 739  * @skb: socket buffer to add attribute to
 740  * @attrtype: attribute type
 741  * @value: numeric value
 742  */
 743 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 744 {
 745         return nla_put(skb, attrtype, sizeof(u8), &value);
 746 }
 747
 748 /**
 749  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 750  * @skb: socket buffer to add attribute to
 751  * @attrtype: attribute type
 752  * @value: numeric value
 753  */
 754 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 755 {
 756         return nla_put(skb, attrtype, sizeof(u16), &value);
 757 }
 758
 759 /**
 760  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 761  * @skb: socket buffer to add attribute to
 762  * @attrtype: attribute type
 763  * @value: numeric value
 764  */
 765 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 766 {
 767         return nla_put(skb, attrtype, sizeof(__be16), &value);
 768 }
 769
 770 /**
 771  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 772  * @skb: socket buffer to add attribute to
 773  * @attrtype: attribute type
 774  * @value: numeric value
 775  */
 776 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 777 {
 778         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 779 }
 780
 781 /**
 782  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 783  * @skb: socket buffer to add attribute to
 784  * @attrtype: attribute type
 785  * @value: numeric value
 786  */
 787 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 788 {
 789         return nla_put(skb, attrtype, sizeof(__le16), &value);
 790 }
 791
 792 /**
 793  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 794  * @skb: socket buffer to add attribute to
 795  * @attrtype: attribute type
 796  * @value: numeric value
 797  */
 798 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 799 {
 800         return nla_put(skb, attrtype, sizeof(u32), &value);
 801 }
 802
 803 /**
 804  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 805  * @skb: socket buffer to add attribute to
 806  * @attrtype: attribute type
 807  * @value: numeric value
 808  */
 809 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 810 {
 811         return nla_put(skb, attrtype, sizeof(__be32), &value);
 812 }
 813
 814 /**
 815  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 816  * @skb: socket buffer to add attribute to
 817  * @attrtype: attribute type
 818  * @value: numeric value
 819  */
 820 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 821 {
 822         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 823 }
 824
 825 /**
 826  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 827  * @skb: socket buffer to add attribute to
 828  * @attrtype: attribute type
 829  * @value: numeric value
 830  */
 831 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 832 {
 833         return nla_put(skb, attrtype, sizeof(__le32), &value);
 834 }
 835
 836 /**
 837  * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
 838  * @skb: socket buffer to add attribute to
 839  * @attrtype: attribute type
 840  * @value: numeric value
 841  */
 842 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 843 {
 844         return nla_put(skb, attrtype, sizeof(u64), &value);
 845 }
 846
 847 /**
 848  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer
 849  * @skb: socket buffer to add attribute to
 850  * @attrtype: attribute type
 851  * @value: numeric value
 852  */
 853 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value)
 854 {
 855         return nla_put(skb, attrtype, sizeof(__be64), &value);
 856 }
 857
 858 /**
 859  * nla_put_net64 - Add 64-bit network byte order netlink attribute to a socket buffer
 860  * @skb: socket buffer to add attribute to
 861  * @attrtype: attribute type
 862  * @value: numeric value
 863  */
 864 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value)
 865 {
 866         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 867 }
 868
 869 /**
 870  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer
 871  * @skb: socket buffer to add attribute to
 872  * @attrtype: attribute type
 873  * @value: numeric value
 874  */
 875 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value)
 876 {
 877         return nla_put(skb, attrtype, sizeof(__le64), &value);
 878 }
 879
 880 /**
 881  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 882  * @skb: socket buffer to add attribute to
 883  * @attrtype: attribute type
 884  * @value: numeric value
 885  */
 886 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 887 {
 888         return nla_put(skb, attrtype, sizeof(s8), &value);
 889 }
 890
 891 /**
 892  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 893  * @skb: socket buffer to add attribute to
 894  * @attrtype: attribute type
 895  * @value: numeric value
 896  */
 897 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 898 {
 899         return nla_put(skb, attrtype, sizeof(s16), &value);
 900 }
 901
 902 /**
 903  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 904  * @skb: socket buffer to add attribute to
 905  * @attrtype: attribute type
 906  * @value: numeric value
 907  */
 908 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 909 {
 910         return nla_put(skb, attrtype, sizeof(s32), &value);
 911 }
 912
 913 /**
 914  * nla_put_s64 - Add a s64 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_s64(struct sk_buff *skb, int attrtype, s64 value)
 920 {
 921         return nla_put(skb, attrtype, sizeof(s64), &value);
 922 }
 923
 924 /**
 925  * nla_put_string - Add a string netlink attribute to a socket buffer
 926  * @skb: socket buffer to add attribute to
 927  * @attrtype: attribute type
 928  * @str: NUL terminated string
 929  */
 930 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 931                                  const char *str)
 932 {
 933         return nla_put(skb, attrtype, strlen(str) + 1, str);
 934 }
 935
 936 /**
 937  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 938  * @skb: socket buffer to add attribute to
 939  * @attrtype: attribute type
 940  */
 941 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 942 {
 943         return nla_put(skb, attrtype, 0, NULL);
 944 }
 945
 946 /**
 947  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 948  * @skb: socket buffer to add attribute to
 949  * @attrtype: attribute type
 950  * @njiffies: number of jiffies to convert to msecs
 951  */
 952 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 953                                 unsigned long njiffies)
 954 {
 955         u64 tmp = jiffies_to_msecs(njiffies);
 956         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 957 }
 958
 959 /**
 960  * nla_get_u32 - return payload of u32 attribute
 961  * @nla: u32 netlink attribute
 962  */
 963 static inline u32 nla_get_u32(const struct nlattr *nla)
 964 {
 965         return *(u32 *) nla_data(nla);
 966 }
 967
 968 /**
 969  * nla_get_be32 - return payload of __be32 attribute
 970  * @nla: __be32 netlink attribute
 971  */
 972 static inline __be32 nla_get_be32(const struct nlattr *nla)
 973 {
 974         return *(__be32 *) nla_data(nla);
 975 }
 976
 977 /**
 978  * nla_get_u16 - return payload of u16 attribute
 979  * @nla: u16 netlink attribute
 980  */
 981 static inline u16 nla_get_u16(const struct nlattr *nla)
 982 {
 983         return *(u16 *) nla_data(nla);
 984 }
 985
 986 /**
 987  * nla_get_be16 - return payload of __be16 attribute
 988  * @nla: __be16 netlink attribute
 989  */
 990 static inline __be16 nla_get_be16(const struct nlattr *nla)
 991 {
 992         return *(__be16 *) nla_data(nla);
 993 }
 994
 995 /**
 996  * nla_get_le16 - return payload of __le16 attribute
 997  * @nla: __le16 netlink attribute
 998  */
 999 static inline __le16 nla_get_le16(const struct nlattr *nla)
1000 {
1001         return *(__le16 *) nla_data(nla);
1002 }
1003
1004 /**
1005  * nla_get_u8 - return payload of u8 attribute
1006  * @nla: u8 netlink attribute
1007  */
1008 static inline u8 nla_get_u8(const struct nlattr *nla)
1009 {
1010         return *(u8 *) nla_data(nla);
1011 }
1012
1013 /**
1014  * nla_get_u64 - return payload of u64 attribute
1015  * @nla: u64 netlink attribute
1016  */
1017 static inline u64 nla_get_u64(const struct nlattr *nla)
1018 {
1019         u64 tmp;
1020
1021         nla_memcpy(&tmp, nla, sizeof(tmp));
1022
1023         return tmp;
1024 }
1025
1026 /**
1027  * nla_get_be64 - return payload of __be64 attribute
1028  * @nla: __be64 netlink attribute
1029  */
1030 static inline __be64 nla_get_be64(const struct nlattr *nla)
1031 {
1032         __be64 tmp;
1033
1034         nla_memcpy(&tmp, nla, sizeof(tmp));
1035
1036         return tmp;
1037 }
1038
1039 /**
1040  * nla_get_s32 - return payload of s32 attribute
1041  * @nla: s32 netlink attribute
1042  */
1043 static inline s32 nla_get_s32(const struct nlattr *nla)
1044 {
1045         return *(s32 *) nla_data(nla);
1046 }
1047
1048 /**
1049  * nla_get_s16 - return payload of s16 attribute
1050  * @nla: s16 netlink attribute
1051  */
1052 static inline s16 nla_get_s16(const struct nlattr *nla)
1053 {
1054         return *(s16 *) nla_data(nla);
1055 }
1056
1057 /**
1058  * nla_get_s8 - return payload of s8 attribute
1059  * @nla: s8 netlink attribute
1060  */
1061 static inline s8 nla_get_s8(const struct nlattr *nla)
1062 {
1063         return *(s8 *) nla_data(nla);
1064 }
1065
1066 /**
1067  * nla_get_s64 - return payload of s64 attribute
1068  * @nla: s64 netlink attribute
1069  */
1070 static inline s64 nla_get_s64(const struct nlattr *nla)
1071 {
1072         s64 tmp;
1073
1074         nla_memcpy(&tmp, nla, sizeof(tmp));
1075
1076         return tmp;
1077 }
1078
1079 /**
1080  * nla_get_flag - return payload of flag attribute
1081  * @nla: flag netlink attribute
1082  */
1083 static inline int nla_get_flag(const struct nlattr *nla)
1084 {
1085         return !!nla;
1086 }
1087
1088 /**
1089  * nla_get_msecs - return payload of msecs attribute
1090  * @nla: msecs netlink attribute
1091  *
1092  * Returns the number of milliseconds in jiffies.
1093  */
1094 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1095 {
1096         u64 msecs = nla_get_u64(nla);
1097
1098         return msecs_to_jiffies((unsigned long) msecs);
1099 }
1100
1101 /**
1102  * nla_nest_start - Start a new level of nested attributes
1103  * @skb: socket buffer to add attributes to
1104  * @attrtype: attribute type of container
1105  *
1106  * Returns the container attribute
1107  */
1108 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1109 {
1110         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1111
1112         if (nla_put(skb, attrtype, 0, NULL) < 0)
1113                 return NULL;
1114
1115         return start;
1116 }
1117
1118 /**
1119  * nla_nest_end - Finalize nesting of attributes
1120  * @skb: socket buffer the attributes are stored in
1121  * @start: container attribute
1122  *
1123  * Corrects the container attribute header to include the all
1124  * appeneded attributes.
1125  *
1126  * Returns the total data length of the skb.
1127  */
1128 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1129 {
1130         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1131         return skb->len;
1132 }
1133
1134 /**
1135  * nla_nest_cancel - Cancel nesting of attributes
1136  * @skb: socket buffer the message is stored in
1137  * @start: container attribute
1138  *
1139  * Removes the container attribute and including all nested
1140  * attributes. Returns -EMSGSIZE
1141  */
1142 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1143 {
1144         nlmsg_trim(skb, start);
1145 }
1146
1147 /**
1148  * nla_validate_nested - Validate a stream of nested attributes
1149  * @start: container attribute
1150  * @maxtype: maximum attribute type to be expected
1151  * @policy: validation policy
1152  *
1153  * Validates all attributes in the nested attribute stream against the
1154  * specified policy. Attributes with a type exceeding maxtype will be
1155  * ignored. See documenation of struct nla_policy for more details.
1156  *
1157  * Returns 0 on success or a negative error code.
1158  */
1159 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1160                                       const struct nla_policy *policy)
1161 {
1162         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1163 }
1164
1165 /**
1166  * nla_for_each_attr - iterate over a stream of attributes
1167  * @pos: loop counter, set to current attribute
1168  * @head: head of attribute stream
1169  * @len: length of attribute stream
1170  * @rem: initialized to len, holds bytes currently remaining in stream
1171  */
1172 #define nla_for_each_attr(pos, head, len, rem) \
1173         for (pos = head, rem = len; \
1174              nla_ok(pos, rem); \
1175              pos = nla_next(pos, &(rem)))
1176
1177 /**
1178  * nla_for_each_nested - iterate over nested attributes
1179  * @pos: loop counter, set to current attribute
1180  * @nla: attribute containing the nested attributes
1181  * @rem: initialized to len, holds bytes currently remaining in stream
1182  */
1183 #define nla_for_each_nested(pos, nla, rem) \
1184         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1185
1186 /**
1187  * nla_is_last - Test if attribute is last in stream
1188  * @nla: attribute to test
1189  * @rem: bytes remaining in stream
1190  */
1191 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1192 {
1193         return nla->nla_len == rem;
1194 }
1195
1196 #endif