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
   7 /* ========================================================================
   8  *         Netlink Messages and Attributes Interface (As Seen On TV)
   9  * ------------------------------------------------------------------------
  10  *                          Messages Interface
  11  * ------------------------------------------------------------------------
  12  *
  13  * Message Format:
  14  *    <--- nlmsg_total_size(payload)  --->
  15  *    <-- nlmsg_msg_size(payload) ->
  16  *   +----------+- - -+-------------+- - -+-------- - -
  17  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  18  *   +----------+- - -+-------------+- - -+-------- - -
  19  *   nlmsg_data(nlh)---^                   ^
  20  *   nlmsg_next(nlh)-----------------------+
  21  *
  22  * Payload Format:
  23  *    <---------------------- nlmsg_len(nlh) --------------------->
  24  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  25  *   +----------------------+- - -+--------------------------------+
  26  *   |     Family Header    | Pad |           Attributes           |
  27  *   +----------------------+- - -+--------------------------------+
  28  *   nlmsg_attrdata(nlh, hdrlen)---^
  29  *
  30  * Data Structures:
  31  *   struct nlmsghdr                    netlink message header
  32  *
  33  * Message Construction:
  34  *   nlmsg_new()                        create a new netlink message
  35  *   nlmsg_put()                        add a netlink message to an skb
  36  *   nlmsg_put_answer()                 callback based nlmsg_put()
  37  *   nlmsg_end()                        finanlize netlink message
  38  *   nlmsg_get_pos()                    return current position in message
  39  *   nlmsg_trim()                       trim part of message
  40  *   nlmsg_cancel()                     cancel message construction
  41  *   nlmsg_free()                       free a netlink message
  42  *
  43  * Message Sending:
  44  *   nlmsg_multicast()                  multicast message to several groups
  45  *   nlmsg_unicast()                    unicast a message to a single socket
  46  *   nlmsg_notify()                     send notification message
  47  *
  48  * Message Length Calculations:
  49  *   nlmsg_msg_size(payload)            length of message w/o padding
  50  *   nlmsg_total_size(payload)          length of message w/ padding
  51  *   nlmsg_padlen(payload)              length of padding at tail
  52  *
  53  * Message Payload Access:
  54  *   nlmsg_data(nlh)                    head of message payload
  55  *   nlmsg_len(nlh)                     length of message payload
  56  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  57  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  58  *
  59  * Message Parsing:
  60  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  61  *   nlmsg_next(nlh, remaining)         get next netlink message
  62  *   nlmsg_parse()                      parse attributes of a message
  63  *   nlmsg_find_attr()                  find an attribute in a message
  64  *   nlmsg_for_each_msg()               loop over all messages
  65  *   nlmsg_validate()                   validate netlink message incl. attrs
  66  *   nlmsg_for_each_attr()              loop over all attributes
  67  *
  68  * Misc:
  69  *   nlmsg_report()                     report back to application?
  70  *
  71  * ------------------------------------------------------------------------
  72  *                          Attributes Interface
  73  * ------------------------------------------------------------------------
  74  *
  75  * Attribute Format:
  76  *    <------- nla_total_size(payload) ------->
  77  *    <---- nla_attr_size(payload) ----->
  78  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  79  *   |  Header  | Pad |     Payload      | Pad |  Header
  80  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  81  *                     <- nla_len(nla) ->      ^
  82  *   nla_data(nla)----^                        |
  83  *   nla_next(nla)-----------------------------'
  84  *
  85  * Data Structures:
  86  *   struct nlattr                      netlink attribtue header
  87  *
  88  * Attribute Construction:
  89  *   nla_reserve(skb, type, len)        reserve room for an attribute
  90  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  91  *   nla_put(skb, type, len, data)      add attribute to skb
  92  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  93  *
  94  * Attribute Construction for Basic Types:
  95  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  96  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  97  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
  98  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
  99  *   nla_put_string(skb, type, str)     add string attribute to skb
 100  *   nla_put_flag(skb, type)            add flag attribute to skb
 101  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 102  *
 103  * Exceptions Based Attribute Construction:
 104  *   NLA_PUT(skb, type, len, data)      add attribute to skb
 105  *   NLA_PUT_U8(skb, type, value)       add u8 attribute to skb
 106  *   NLA_PUT_U16(skb, type, value)      add u16 attribute to skb
 107  *   NLA_PUT_U32(skb, type, value)      add u32 attribute to skb
 108  *   NLA_PUT_U64(skb, type, value)      add u64 attribute to skb
 109  *   NLA_PUT_STRING(skb, type, str)     add string attribute to skb
 110  *   NLA_PUT_FLAG(skb, type)            add flag attribute to skb
 111  *   NLA_PUT_MSECS(skb, type, jiffies)  add msecs attribute to skb
 112  *
 113  *   The meaning of these functions is equal to their lower case
 114  *   variants but they jump to the label nla_put_failure in case
 115  *   of a failure.
 116  *
 117  * Nested Attributes Construction:
 118  *   nla_nest_start(skb, type)          start a nested attribute
 119  *   nla_nest_end(skb, nla)             finalize a nested attribute
 120  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 121  *
 122  * Attribute Length Calculations:
 123  *   nla_attr_size(payload)             length of attribute w/o padding
 124  *   nla_total_size(payload)            length of attribute w/ padding
 125  *   nla_padlen(payload)                length of padding
 126  *
 127  * Attribute Payload Access:
 128  *   nla_data(nla)                      head of attribute payload
 129  *   nla_len(nla)                       length of attribute payload
 130  *
 131  * Attribute Payload Access for Basic Types:
 132  *   nla_get_u8(nla)                    get payload for a u8 attribute
 133  *   nla_get_u16(nla)                   get payload for a u16 attribute
 134  *   nla_get_u32(nla)                   get payload for a u32 attribute
 135  *   nla_get_u64(nla)                   get payload for a u64 attribute
 136  *   nla_get_flag(nla)                  return 1 if flag is true
 137  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 138  *
 139  * Attribute Misc:
 140  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 141  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 142  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 143  *   nla_strcmp(nla, str)               compare attribute with string
 144  *
 145  * Attribute Parsing:
 146  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 147  *   nla_next(nla, remaining)           get next netlink attribute
 148  *   nla_validate()                     validate a stream of attributes
 149  *   nla_validate_nested()              validate a stream of nested attributes
 150  *   nla_find()                         find attribute in stream of attributes
 151  *   nla_find_nested()                  find attribute in nested attributes
 152  *   nla_parse()                        parse and validate stream of attrs
 153  *   nla_parse_nested()                 parse nested attribuets
 154  *   nla_for_each_attr()                loop over all attributes
 155  *   nla_for_each_nested()              loop over the nested attributes
 156  *=========================================================================
 157  */
 158
 159  /**
 160   * Standard attribute types to specify validation policy
 161   */
 162 enum {
 163         NLA_UNSPEC,
 164         NLA_U8,
 165         NLA_U16,
 166         NLA_U32,
 167         NLA_U64,
 168         NLA_STRING,
 169         NLA_FLAG,
 170         NLA_MSECS,
 171         NLA_NESTED,
 172         NLA_NUL_STRING,
 173         __NLA_TYPE_MAX,
 174 };
 175
 176 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 177
 178 /**
 179  * struct nla_policy - attribute validation policy
 180  * @type: Type of attribute or NLA_UNSPEC
 181  * @len: Type specific length of payload
 182  *
 183  * Policies are defined as arrays of this struct, the array must be
 184  * accessible by attribute type up to the highest identifier to be expected.
 185  *
 186  * Meaning of `len' field:
 187  *    NLA_STRING           Maximum length of string
 188  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 189  *    NLA_FLAG             Unused
 190  *    All other            Exact length of attribute payload
 191  *
 192  * Example:
 193  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 194  *      [ATTR_FOO] = { .type = NLA_U16 },
 195  *      [ATTR_BAR] = { .type = NLA_STRING, len = BARSIZ },
 196  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 197  * };
 198  */
 199 struct nla_policy {
 200         u16             type;
 201         u16             len;
 202 };
 203
 204 /**
 205  * struct nl_info - netlink source information
 206  * @nlh: Netlink message header of original request
 207  * @pid: Netlink PID of requesting application
 208  */
 209 struct nl_info {
 210         struct nlmsghdr         *nlh;
 211         u32                     pid;
 212 };
 213
 214 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 215                                           int (*cb)(struct sk_buff *,
 216                                                     struct nlmsghdr *, int *));
 217 extern void             netlink_queue_skip(struct nlmsghdr *nlh,
 218                                            struct sk_buff *skb);
 219 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 220                                      u32 pid, unsigned int group, int report,
 221                                      gfp_t flags);
 222
 223 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 224                                      struct nla_policy *policy);
 225 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 226                                   struct nlattr *head, int len,
 227                                   struct nla_policy *policy);
 228 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 229 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 230                                     size_t dstsize);
 231 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 232 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 233                                    size_t size);
 234 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 235 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 236                                       int attrlen);
 237 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 238 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 239                                     int attrlen);
 240 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 241 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 242                                   int attrlen, const void *data);
 243 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 244                                         const void *data);
 245 extern int              nla_put(struct sk_buff *skb, int attrtype,
 246                                 int attrlen, const void *data);
 247 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 248                                       const void *data);
 249
 250 /**************************************************************************
 251  * Netlink Messages
 252  **************************************************************************/
 253
 254 /**
 255  * nlmsg_msg_size - length of netlink message not including padding
 256  * @payload: length of message payload
 257  */
 258 static inline int nlmsg_msg_size(int payload)
 259 {
 260         return NLMSG_HDRLEN + payload;
 261 }
 262
 263 /**
 264  * nlmsg_total_size - length of netlink message including padding
 265  * @payload: length of message payload
 266  */
 267 static inline int nlmsg_total_size(int payload)
 268 {
 269         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 270 }
 271
 272 /**
 273  * nlmsg_padlen - length of padding at the message's tail
 274  * @payload: length of message payload
 275  */
 276 static inline int nlmsg_padlen(int payload)
 277 {
 278         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 279 }
 280
 281 /**
 282  * nlmsg_data - head of message payload
 283  * @nlh: netlink messsage header
 284  */
 285 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 286 {
 287         return (unsigned char *) nlh + NLMSG_HDRLEN;
 288 }
 289
 290 /**
 291  * nlmsg_len - length of message payload
 292  * @nlh: netlink message header
 293  */
 294 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 295 {
 296         return nlh->nlmsg_len - NLMSG_HDRLEN;
 297 }
 298
 299 /**
 300  * nlmsg_attrdata - head of attributes data
 301  * @nlh: netlink message header
 302  * @hdrlen: length of family specific header
 303  */
 304 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 305                                             int hdrlen)
 306 {
 307         unsigned char *data = nlmsg_data(nlh);
 308         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 309 }
 310
 311 /**
 312  * nlmsg_attrlen - length of attributes data
 313  * @nlh: netlink message header
 314  * @hdrlen: length of family specific header
 315  */
 316 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 317 {
 318         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 319 }
 320
 321 /**
 322  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 323  * @nlh: netlink message header
 324  * @remaining: number of bytes remaining in message stream
 325  */
 326 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 327 {
 328         return (remaining >= sizeof(struct nlmsghdr) &&
 329                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 330                 nlh->nlmsg_len <= remaining);
 331 }
 332
 333 /**
 334  * nlmsg_next - next netlink message in message stream
 335  * @nlh: netlink message header
 336  * @remaining: number of bytes remaining in message stream
 337  *
 338  * Returns the next netlink message in the message stream and
 339  * decrements remaining by the size of the current message.
 340  */
 341 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 342 {
 343         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 344
 345         *remaining -= totlen;
 346
 347         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 348 }
 349
 350 /**
 351  * nlmsg_parse - parse attributes of a netlink message
 352  * @nlh: netlink message header
 353  * @hdrlen: length of family specific header
 354  * @tb: destination array with maxtype+1 elements
 355  * @maxtype: maximum attribute type to be expected
 356  * @policy: validation policy
 357  *
 358  * See nla_parse()
 359  */
 360 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 361                               struct nlattr *tb[], int maxtype,
 362                               struct nla_policy *policy)
 363 {
 364         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 365                 return -EINVAL;
 366
 367         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 368                          nlmsg_attrlen(nlh, hdrlen), policy);
 369 }
 370
 371 /**
 372  * nlmsg_find_attr - find a specific attribute in a netlink message
 373  * @nlh: netlink message header
 374  * @hdrlen: length of familiy specific header
 375  * @attrtype: type of attribute to look for
 376  *
 377  * Returns the first attribute which matches the specified type.
 378  */
 379 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 380                                              int hdrlen, int attrtype)
 381 {
 382         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 383                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 384 }
 385
 386 /**
 387  * nlmsg_validate - validate a netlink message including attributes
 388  * @nlh: netlinket message header
 389  * @hdrlen: length of familiy specific header
 390  * @maxtype: maximum attribute type to be expected
 391  * @policy: validation policy
 392  */
 393 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 394                                  struct nla_policy *policy)
 395 {
 396         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 397                 return -EINVAL;
 398
 399         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 400                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 401 }
 402
 403 /**
 404  * nlmsg_report - need to report back to application?
 405  * @nlh: netlink message header
 406  *
 407  * Returns 1 if a report back to the application is requested.
 408  */
 409 static inline int nlmsg_report(struct nlmsghdr *nlh)
 410 {
 411         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 412 }
 413
 414 /**
 415  * nlmsg_for_each_attr - iterate over a stream of attributes
 416  * @pos: loop counter, set to current attribute
 417  * @nlh: netlink message header
 418  * @hdrlen: length of familiy specific header
 419  * @rem: initialized to len, holds bytes currently remaining in stream
 420  */
 421 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 422         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 423                           nlmsg_attrlen(nlh, hdrlen), rem)
 424
 425 #if 0
 426 /* FIXME: Enable once all users have been converted */
 427
 428 /**
 429  * __nlmsg_put - Add a new netlink message to an skb
 430  * @skb: socket buffer to store message in
 431  * @pid: netlink process id
 432  * @seq: sequence number of message
 433  * @type: message type
 434  * @payload: length of message payload
 435  * @flags: message flags
 436  *
 437  * The caller is responsible to ensure that the skb provides enough
 438  * tailroom for both the netlink header and payload.
 439  */
 440 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 441                                            u32 seq, int type, int payload,
 442                                            int flags)
 443 {
 444         struct nlmsghdr *nlh;
 445
 446         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 447         nlh->nlmsg_type = type;
 448         nlh->nlmsg_len = nlmsg_msg_size(payload);
 449         nlh->nlmsg_flags = flags;
 450         nlh->nlmsg_pid = pid;
 451         nlh->nlmsg_seq = seq;
 452
 453         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 454                nlmsg_padlen(payload));
 455
 456         return nlh;
 457 }
 458 #endif
 459
 460 /**
 461  * nlmsg_put - Add a new netlink message to an skb
 462  * @skb: socket buffer to store message in
 463  * @pid: netlink process id
 464  * @seq: sequence number of message
 465  * @type: message type
 466  * @payload: length of message payload
 467  * @flags: message flags
 468  *
 469  * Returns NULL if the tailroom of the skb is insufficient to store
 470  * the message header and payload.
 471  */
 472 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 473                                          int type, int payload, int flags)
 474 {
 475         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 476                 return NULL;
 477
 478         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 479 }
 480
 481 /**
 482  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 483  * @skb: socket buffer to store message in
 484  * @cb: netlink callback
 485  * @type: message type
 486  * @payload: length of message payload
 487  * @flags: message flags
 488  *
 489  * Returns NULL if the tailroom of the skb is insufficient to store
 490  * the message header and payload.
 491  */
 492 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 493                                                 struct netlink_callback *cb,
 494                                                 int type, int payload,
 495                                                 int flags)
 496 {
 497         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 498                          type, payload, flags);
 499 }
 500
 501 /**
 502  * nlmsg_new - Allocate a new netlink message
 503  * @payload: size of the message payload
 504  * @flags: the type of memory to allocate.
 505  *
 506  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 507  * and a good default is needed.
 508  */
 509 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 510 {
 511         return alloc_skb(nlmsg_total_size(payload), flags);
 512 }
 513
 514 /**
 515  * nlmsg_end - Finalize a netlink message
 516  * @skb: socket buffer the message is stored in
 517  * @nlh: netlink message header
 518  *
 519  * Corrects the netlink message header to include the appeneded
 520  * attributes. Only necessary if attributes have been added to
 521  * the message.
 522  *
 523  * Returns the total data length of the skb.
 524  */
 525 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 526 {
 527         nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
 528
 529         return skb->len;
 530 }
 531
 532 /**
 533  * nlmsg_get_pos - return current position in netlink message
 534  * @skb: socket buffer the message is stored in
 535  *
 536  * Returns a pointer to the current tail of the message.
 537  */
 538 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 539 {
 540         return skb->tail;
 541 }
 542
 543 /**
 544  * nlmsg_trim - Trim message to a mark
 545  * @skb: socket buffer the message is stored in
 546  * @mark: mark to trim to
 547  *
 548  * Trims the message to the provided mark. Returns -1.
 549  */
 550 static inline int nlmsg_trim(struct sk_buff *skb, void *mark)
 551 {
 552         if (mark)
 553                 skb_trim(skb, (unsigned char *) mark - skb->data);
 554
 555         return -1;
 556 }
 557
 558 /**
 559  * nlmsg_cancel - Cancel construction of a netlink message
 560  * @skb: socket buffer the message is stored in
 561  * @nlh: netlink message header
 562  *
 563  * Removes the complete netlink message including all
 564  * attributes from the socket buffer again. Returns -1.
 565  */
 566 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 567 {
 568         return nlmsg_trim(skb, nlh);
 569 }
 570
 571 /**
 572  * nlmsg_free - free a netlink message
 573  * @skb: socket buffer of netlink message
 574  */
 575 static inline void nlmsg_free(struct sk_buff *skb)
 576 {
 577         kfree_skb(skb);
 578 }
 579
 580 /**
 581  * nlmsg_multicast - multicast a netlink message
 582  * @sk: netlink socket to spread messages to
 583  * @skb: netlink message as socket buffer
 584  * @pid: own netlink pid to avoid sending to yourself
 585  * @group: multicast group id
 586  * @flags: allocation flags
 587  */
 588 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 589                                   u32 pid, unsigned int group, gfp_t flags)
 590 {
 591         int err;
 592
 593         NETLINK_CB(skb).dst_group = group;
 594
 595         err = netlink_broadcast(sk, skb, pid, group, flags);
 596         if (err > 0)
 597                 err = 0;
 598
 599         return err;
 600 }
 601
 602 /**
 603  * nlmsg_unicast - unicast a netlink message
 604  * @sk: netlink socket to spread message to
 605  * @skb: netlink message as socket buffer
 606  * @pid: netlink pid of the destination socket
 607  */
 608 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 609 {
 610         int err;
 611
 612         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 613         if (err > 0)
 614                 err = 0;
 615
 616         return err;
 617 }
 618
 619 /**
 620  * nlmsg_for_each_msg - iterate over a stream of messages
 621  * @pos: loop counter, set to current message
 622  * @head: head of message stream
 623  * @len: length of message stream
 624  * @rem: initialized to len, holds bytes currently remaining in stream
 625  */
 626 #define nlmsg_for_each_msg(pos, head, len, rem) \
 627         for (pos = head, rem = len; \
 628              nlmsg_ok(pos, rem); \
 629              pos = nlmsg_next(pos, &(rem)))
 630
 631 /**************************************************************************
 632  * Netlink Attributes
 633  **************************************************************************/
 634
 635 /**
 636  * nla_attr_size - length of attribute not including padding
 637  * @payload: length of payload
 638  */
 639 static inline int nla_attr_size(int payload)
 640 {
 641         return NLA_HDRLEN + payload;
 642 }
 643
 644 /**
 645  * nla_total_size - total length of attribute including padding
 646  * @payload: length of payload
 647  */
 648 static inline int nla_total_size(int payload)
 649 {
 650         return NLA_ALIGN(nla_attr_size(payload));
 651 }
 652
 653 /**
 654  * nla_padlen - length of padding at the tail of attribute
 655  * @payload: length of payload
 656  */
 657 static inline int nla_padlen(int payload)
 658 {
 659         return nla_total_size(payload) - nla_attr_size(payload);
 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 >= sizeof(*nla) &&
 688                nla->nla_len >= sizeof(*nla) &&
 689                nla->nla_len <= remaining;
 690 }
 691
 692 /**
 693  * nla_next - next netlink attribte 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 *nla_find_nested(struct nlattr *nla, int attrtype)
 716 {
 717         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 718 }
 719
 720 /**
 721  * nla_parse_nested - parse nested attributes
 722  * @tb: destination array with maxtype+1 elements
 723  * @maxtype: maximum attribute type to be expected
 724  * @nla: attribute containing the nested attributes
 725  * @policy: validation policy
 726  *
 727  * See nla_parse()
 728  */
 729 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 730                                    struct nlattr *nla,
 731                                    struct nla_policy *policy)
 732 {
 733         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 734 }
 735 /**
 736  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 737  * @skb: socket buffer to add attribute to
 738  * @attrtype: attribute type
 739  * @value: numeric value
 740  */
 741 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 742 {
 743         return nla_put(skb, attrtype, sizeof(u8), &value);
 744 }
 745
 746 /**
 747  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 748  * @skb: socket buffer to add attribute to
 749  * @attrtype: attribute type
 750  * @value: numeric value
 751  */
 752 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 753 {
 754         return nla_put(skb, attrtype, sizeof(u16), &value);
 755 }
 756
 757 /**
 758  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 759  * @skb: socket buffer to add attribute to
 760  * @attrtype: attribute type
 761  * @value: numeric value
 762  */
 763 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 764 {
 765         return nla_put(skb, attrtype, sizeof(u32), &value);
 766 }
 767
 768 /**
 769  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 770  * @skb: socket buffer to add attribute to
 771  * @attrtype: attribute type
 772  * @value: numeric value
 773  */
 774 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 775 {
 776         return nla_put(skb, attrtype, sizeof(u64), &value);
 777 }
 778
 779 /**
 780  * nla_put_string - Add a string netlink attribute to a socket buffer
 781  * @skb: socket buffer to add attribute to
 782  * @attrtype: attribute type
 783  * @str: NUL terminated string
 784  */
 785 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 786                                  const char *str)
 787 {
 788         return nla_put(skb, attrtype, strlen(str) + 1, str);
 789 }
 790
 791 /**
 792  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 793  * @skb: socket buffer to add attribute to
 794  * @attrtype: attribute type
 795  */
 796 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 797 {
 798         return nla_put(skb, attrtype, 0, NULL);
 799 }
 800
 801 /**
 802  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 803  * @skb: socket buffer to add attribute to
 804  * @attrtype: attribute type
 805  * @jiffies: number of msecs in jiffies
 806  */
 807 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 808                                 unsigned long jiffies)
 809 {
 810         u64 tmp = jiffies_to_msecs(jiffies);
 811         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 812 }
 813
 814 #define NLA_PUT(skb, attrtype, attrlen, data) \
 815         do { \
 816                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 817                         goto nla_put_failure; \
 818         } while(0)
 819
 820 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 821         do { \
 822                 type __tmp = value; \
 823                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 824         } while(0)
 825
 826 #define NLA_PUT_U8(skb, attrtype, value) \
 827         NLA_PUT_TYPE(skb, u8, attrtype, value)
 828
 829 #define NLA_PUT_U16(skb, attrtype, value) \
 830         NLA_PUT_TYPE(skb, u16, attrtype, value)
 831
 832 #define NLA_PUT_U32(skb, attrtype, value) \
 833         NLA_PUT_TYPE(skb, u32, attrtype, value)
 834
 835 #define NLA_PUT_BE32(skb, attrtype, value) \
 836         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 837
 838 #define NLA_PUT_U64(skb, attrtype, value) \
 839         NLA_PUT_TYPE(skb, u64, attrtype, value)
 840
 841 #define NLA_PUT_STRING(skb, attrtype, value) \
 842         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 843
 844 #define NLA_PUT_FLAG(skb, attrtype) \
 845         NLA_PUT(skb, attrtype, 0, NULL)
 846
 847 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 848         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 849
 850 /**
 851  * nla_get_u32 - return payload of u32 attribute
 852  * @nla: u32 netlink attribute
 853  */
 854 static inline u32 nla_get_u32(struct nlattr *nla)
 855 {
 856         return *(u32 *) nla_data(nla);
 857 }
 858
 859 /**
 860  * nla_get_be32 - return payload of __be32 attribute
 861  * @nla: __be32 netlink attribute
 862  */
 863 static inline __be32 nla_get_be32(struct nlattr *nla)
 864 {
 865         return *(__be32 *) nla_data(nla);
 866 }
 867
 868 /**
 869  * nla_get_u16 - return payload of u16 attribute
 870  * @nla: u16 netlink attribute
 871  */
 872 static inline u16 nla_get_u16(struct nlattr *nla)
 873 {
 874         return *(u16 *) nla_data(nla);
 875 }
 876
 877 /**
 878  * nla_get_u8 - return payload of u8 attribute
 879  * @nla: u8 netlink attribute
 880  */
 881 static inline u8 nla_get_u8(struct nlattr *nla)
 882 {
 883         return *(u8 *) nla_data(nla);
 884 }
 885
 886 /**
 887  * nla_get_u64 - return payload of u64 attribute
 888  * @nla: u64 netlink attribute
 889  */
 890 static inline u64 nla_get_u64(struct nlattr *nla)
 891 {
 892         u64 tmp;
 893
 894         nla_memcpy(&tmp, nla, sizeof(tmp));
 895
 896         return tmp;
 897 }
 898
 899 /**
 900  * nla_get_flag - return payload of flag attribute
 901  * @nla: flag netlink attribute
 902  */
 903 static inline int nla_get_flag(struct nlattr *nla)
 904 {
 905         return !!nla;
 906 }
 907
 908 /**
 909  * nla_get_msecs - return payload of msecs attribute
 910  * @nla: msecs netlink attribute
 911  *
 912  * Returns the number of milliseconds in jiffies.
 913  */
 914 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 915 {
 916         u64 msecs = nla_get_u64(nla);
 917
 918         return msecs_to_jiffies((unsigned long) msecs);
 919 }
 920
 921 /**
 922  * nla_nest_start - Start a new level of nested attributes
 923  * @skb: socket buffer to add attributes to
 924  * @attrtype: attribute type of container
 925  *
 926  * Returns the container attribute
 927  */
 928 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 929 {
 930         struct nlattr *start = (struct nlattr *) skb->tail;
 931
 932         if (nla_put(skb, attrtype, 0, NULL) < 0)
 933                 return NULL;
 934
 935         return start;
 936 }
 937
 938 /**
 939  * nla_nest_end - Finalize nesting of attributes
 940  * @skb: socket buffer the attribtues are stored in
 941  * @start: container attribute
 942  *
 943  * Corrects the container attribute header to include the all
 944  * appeneded attributes.
 945  *
 946  * Returns the total data length of the skb.
 947  */
 948 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 949 {
 950         start->nla_len = skb->tail - (unsigned char *) start;
 951         return skb->len;
 952 }
 953
 954 /**
 955  * nla_nest_cancel - Cancel nesting of attributes
 956  * @skb: socket buffer the message is stored in
 957  * @start: container attribute
 958  *
 959  * Removes the container attribute and including all nested
 960  * attributes. Returns -1.
 961  */
 962 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 963 {
 964         return nlmsg_trim(skb, start);
 965 }
 966
 967 /**
 968  * nla_validate_nested - Validate a stream of nested attributes
 969  * @start: container attribute
 970  * @maxtype: maximum attribute type to be expected
 971  * @policy: validation policy
 972  *
 973  * Validates all attributes in the nested attribute stream against the
 974  * specified policy. Attributes with a type exceeding maxtype will be
 975  * ignored. See documenation of struct nla_policy for more details.
 976  *
 977  * Returns 0 on success or a negative error code.
 978  */
 979 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
 980                                       struct nla_policy *policy)
 981 {
 982         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
 983 }
 984
 985 /**
 986  * nla_for_each_attr - iterate over a stream of attributes
 987  * @pos: loop counter, set to current attribute
 988  * @head: head of attribute stream
 989  * @len: length of attribute stream
 990  * @rem: initialized to len, holds bytes currently remaining in stream
 991  */
 992 #define nla_for_each_attr(pos, head, len, rem) \
 993         for (pos = head, rem = len; \
 994              nla_ok(pos, rem); \
 995              pos = nla_next(pos, &(rem)))
 996
 997 /**
 998  * nla_for_each_nested - iterate over nested attributes
 999  * @pos: loop counter, set to current attribute
1000  * @nla: attribute containing the nested attributes
1001  * @rem: initialized to len, holds bytes currently remaining in stream
1002  */
1003 #define nla_for_each_nested(pos, nla, rem) \
1004         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1005
1006 #endif