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()                        finanlize 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 attribtue 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  *
  95  * Attribute Construction for Basic Types:
  96  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  97  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  98  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
  99  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
 100  *   nla_put_string(skb, type, str)     add string attribute to skb
 101  *   nla_put_flag(skb, type)            add flag attribute to skb
 102  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 103  *
 104  * Exceptions Based Attribute Construction:
 105  *   NLA_PUT(skb, type, len, data)      add attribute to skb
 106  *   NLA_PUT_U8(skb, type, value)       add u8 attribute to skb
 107  *   NLA_PUT_U16(skb, type, value)      add u16 attribute to skb
 108  *   NLA_PUT_U32(skb, type, value)      add u32 attribute to skb
 109  *   NLA_PUT_U64(skb, type, value)      add u64 attribute to skb
 110  *   NLA_PUT_STRING(skb, type, str)     add string attribute to skb
 111  *   NLA_PUT_FLAG(skb, type)            add flag attribute to skb
 112  *   NLA_PUT_MSECS(skb, type, jiffies)  add msecs attribute to skb
 113  *
 114  *   The meaning of these functions is equal to their lower case
 115  *   variants but they jump to the label nla_put_failure in case
 116  *   of a failure.
 117  *
 118  * Nested Attributes Construction:
 119  *   nla_nest_start(skb, type)          start a nested attribute
 120  *   nla_nest_end(skb, nla)             finalize a nested attribute
 121  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 122  *
 123  * Attribute Length Calculations:
 124  *   nla_attr_size(payload)             length of attribute w/o padding
 125  *   nla_total_size(payload)            length of attribute w/ padding
 126  *   nla_padlen(payload)                length of padding
 127  *
 128  * Attribute Payload Access:
 129  *   nla_data(nla)                      head of attribute payload
 130  *   nla_len(nla)                       length of attribute payload
 131  *
 132  * Attribute Payload Access for Basic Types:
 133  *   nla_get_u8(nla)                    get payload for a u8 attribute
 134  *   nla_get_u16(nla)                   get payload for a u16 attribute
 135  *   nla_get_u32(nla)                   get payload for a u32 attribute
 136  *   nla_get_u64(nla)                   get payload for a u64 attribute
 137  *   nla_get_flag(nla)                  return 1 if flag is true
 138  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 139  *
 140  * Attribute Misc:
 141  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 142  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 143  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 144  *   nla_strcmp(nla, str)               compare attribute with string
 145  *
 146  * Attribute Parsing:
 147  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 148  *   nla_next(nla, remaining)           get next netlink attribute
 149  *   nla_validate()                     validate a stream of attributes
 150  *   nla_validate_nested()              validate a stream of nested attributes
 151  *   nla_find()                         find attribute in stream of attributes
 152  *   nla_find_nested()                  find attribute in nested attributes
 153  *   nla_parse()                        parse and validate stream of attrs
 154  *   nla_parse_nested()                 parse nested attribuets
 155  *   nla_for_each_attr()                loop over all attributes
 156  *   nla_for_each_nested()              loop over the nested attributes
 157  *=========================================================================
 158  */
 159
 160  /**
 161   * Standard attribute types to specify validation policy
 162   */
 163 enum {
 164         NLA_UNSPEC,
 165         NLA_U8,
 166         NLA_U16,
 167         NLA_U32,
 168         NLA_U64,
 169         NLA_STRING,
 170         NLA_FLAG,
 171         NLA_MSECS,
 172         NLA_NESTED,
 173         NLA_NUL_STRING,
 174         NLA_BINARY,
 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  *    All other            Exact length of attribute payload
 194  *
 195  * Example:
 196  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 197  *      [ATTR_FOO] = { .type = NLA_U16 },
 198  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 199  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 200  * };
 201  */
 202 struct nla_policy {
 203         u16             type;
 204         u16             len;
 205 };
 206
 207 /**
 208  * struct nl_info - netlink source information
 209  * @nlh: Netlink message header of original request
 210  * @pid: Netlink PID of requesting application
 211  */
 212 struct nl_info {
 213         struct nlmsghdr         *nlh;
 214         u32                     pid;
 215 };
 216
 217 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 218                                           int (*cb)(struct sk_buff *,
 219                                                     struct nlmsghdr *));
 220 extern void             netlink_queue_skip(struct nlmsghdr *nlh,
 221                                            struct sk_buff *skb);
 222 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 223                                      u32 pid, unsigned int group, int report,
 224                                      gfp_t flags);
 225
 226 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 227                                      struct nla_policy *policy);
 228 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 229                                   struct nlattr *head, int len,
 230                                   struct nla_policy *policy);
 231 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 232 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 233                                     size_t dstsize);
 234 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 235 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 236                                    size_t size);
 237 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 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 struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 242                                     int attrlen);
 243 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 244 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 245                                   int attrlen, const void *data);
 246 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 247                                         const void *data);
 248 extern int              nla_put(struct sk_buff *skb, int attrtype,
 249                                 int attrlen, const void *data);
 250 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 251                                       const void *data);
 252
 253 /**************************************************************************
 254  * Netlink Messages
 255  **************************************************************************/
 256
 257 /**
 258  * nlmsg_msg_size - length of netlink message not including padding
 259  * @payload: length of message payload
 260  */
 261 static inline int nlmsg_msg_size(int payload)
 262 {
 263         return NLMSG_HDRLEN + payload;
 264 }
 265
 266 /**
 267  * nlmsg_total_size - length of netlink message including padding
 268  * @payload: length of message payload
 269  */
 270 static inline int nlmsg_total_size(int payload)
 271 {
 272         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 273 }
 274
 275 /**
 276  * nlmsg_padlen - length of padding at the message's tail
 277  * @payload: length of message payload
 278  */
 279 static inline int nlmsg_padlen(int payload)
 280 {
 281         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 282 }
 283
 284 /**
 285  * nlmsg_data - head of message payload
 286  * @nlh: netlink messsage header
 287  */
 288 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 289 {
 290         return (unsigned char *) nlh + NLMSG_HDRLEN;
 291 }
 292
 293 /**
 294  * nlmsg_len - length of message payload
 295  * @nlh: netlink message header
 296  */
 297 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 298 {
 299         return nlh->nlmsg_len - NLMSG_HDRLEN;
 300 }
 301
 302 /**
 303  * nlmsg_attrdata - head of attributes data
 304  * @nlh: netlink message header
 305  * @hdrlen: length of family specific header
 306  */
 307 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 308                                             int hdrlen)
 309 {
 310         unsigned char *data = nlmsg_data(nlh);
 311         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 312 }
 313
 314 /**
 315  * nlmsg_attrlen - length of attributes data
 316  * @nlh: netlink message header
 317  * @hdrlen: length of family specific header
 318  */
 319 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 320 {
 321         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 322 }
 323
 324 /**
 325  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 326  * @nlh: netlink message header
 327  * @remaining: number of bytes remaining in message stream
 328  */
 329 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 330 {
 331         return (remaining >= sizeof(struct nlmsghdr) &&
 332                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 333                 nlh->nlmsg_len <= remaining);
 334 }
 335
 336 /**
 337  * nlmsg_next - next netlink message in message stream
 338  * @nlh: netlink message header
 339  * @remaining: number of bytes remaining in message stream
 340  *
 341  * Returns the next netlink message in the message stream and
 342  * decrements remaining by the size of the current message.
 343  */
 344 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 345 {
 346         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 347
 348         *remaining -= totlen;
 349
 350         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 351 }
 352
 353 /**
 354  * nlmsg_parse - parse attributes of a netlink message
 355  * @nlh: netlink message header
 356  * @hdrlen: length of family specific header
 357  * @tb: destination array with maxtype+1 elements
 358  * @maxtype: maximum attribute type to be expected
 359  * @policy: validation policy
 360  *
 361  * See nla_parse()
 362  */
 363 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 364                               struct nlattr *tb[], int maxtype,
 365                               struct nla_policy *policy)
 366 {
 367         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 368                 return -EINVAL;
 369
 370         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 371                          nlmsg_attrlen(nlh, hdrlen), policy);
 372 }
 373
 374 /**
 375  * nlmsg_find_attr - find a specific attribute in a netlink message
 376  * @nlh: netlink message header
 377  * @hdrlen: length of familiy specific header
 378  * @attrtype: type of attribute to look for
 379  *
 380  * Returns the first attribute which matches the specified type.
 381  */
 382 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 383                                              int hdrlen, int attrtype)
 384 {
 385         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 386                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 387 }
 388
 389 /**
 390  * nlmsg_validate - validate a netlink message including attributes
 391  * @nlh: netlinket message header
 392  * @hdrlen: length of familiy specific header
 393  * @maxtype: maximum attribute type to be expected
 394  * @policy: validation policy
 395  */
 396 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 397                                  struct nla_policy *policy)
 398 {
 399         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 400                 return -EINVAL;
 401
 402         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 403                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 404 }
 405
 406 /**
 407  * nlmsg_report - need to report back to application?
 408  * @nlh: netlink message header
 409  *
 410  * Returns 1 if a report back to the application is requested.
 411  */
 412 static inline int nlmsg_report(struct nlmsghdr *nlh)
 413 {
 414         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 415 }
 416
 417 /**
 418  * nlmsg_for_each_attr - iterate over a stream of attributes
 419  * @pos: loop counter, set to current attribute
 420  * @nlh: netlink message header
 421  * @hdrlen: length of familiy specific header
 422  * @rem: initialized to len, holds bytes currently remaining in stream
 423  */
 424 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 425         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 426                           nlmsg_attrlen(nlh, hdrlen), rem)
 427
 428 #if 0
 429 /* FIXME: Enable once all users have been converted */
 430
 431 /**
 432  * __nlmsg_put - Add a new netlink message to an skb
 433  * @skb: socket buffer to store message in
 434  * @pid: netlink process id
 435  * @seq: sequence number of message
 436  * @type: message type
 437  * @payload: length of message payload
 438  * @flags: message flags
 439  *
 440  * The caller is responsible to ensure that the skb provides enough
 441  * tailroom for both the netlink header and payload.
 442  */
 443 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 444                                            u32 seq, int type, int payload,
 445                                            int flags)
 446 {
 447         struct nlmsghdr *nlh;
 448
 449         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 450         nlh->nlmsg_type = type;
 451         nlh->nlmsg_len = nlmsg_msg_size(payload);
 452         nlh->nlmsg_flags = flags;
 453         nlh->nlmsg_pid = pid;
 454         nlh->nlmsg_seq = seq;
 455
 456         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 457                nlmsg_padlen(payload));
 458
 459         return nlh;
 460 }
 461 #endif
 462
 463 /**
 464  * nlmsg_put - Add a new netlink message to an skb
 465  * @skb: socket buffer to store message in
 466  * @pid: netlink process id
 467  * @seq: sequence number of message
 468  * @type: message type
 469  * @payload: length of message payload
 470  * @flags: message flags
 471  *
 472  * Returns NULL if the tailroom of the skb is insufficient to store
 473  * the message header and payload.
 474  */
 475 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 476                                          int type, int payload, int flags)
 477 {
 478         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 479                 return NULL;
 480
 481         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 482 }
 483
 484 /**
 485  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 486  * @skb: socket buffer to store message in
 487  * @cb: netlink callback
 488  * @type: message type
 489  * @payload: length of message payload
 490  * @flags: message flags
 491  *
 492  * Returns NULL if the tailroom of the skb is insufficient to store
 493  * the message header and payload.
 494  */
 495 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 496                                                 struct netlink_callback *cb,
 497                                                 int type, int payload,
 498                                                 int flags)
 499 {
 500         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 501                          type, payload, flags);
 502 }
 503
 504 /**
 505  * nlmsg_new - Allocate a new netlink message
 506  * @payload: size of the message payload
 507  * @flags: the type of memory to allocate.
 508  *
 509  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 510  * and a good default is needed.
 511  */
 512 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 513 {
 514         return alloc_skb(nlmsg_total_size(payload), flags);
 515 }
 516
 517 /**
 518  * nlmsg_end - Finalize a netlink message
 519  * @skb: socket buffer the message is stored in
 520  * @nlh: netlink message header
 521  *
 522  * Corrects the netlink message header to include the appeneded
 523  * attributes. Only necessary if attributes have been added to
 524  * the message.
 525  *
 526  * Returns the total data length of the skb.
 527  */
 528 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 529 {
 530         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 531
 532         return skb->len;
 533 }
 534
 535 /**
 536  * nlmsg_get_pos - return current position in netlink message
 537  * @skb: socket buffer the message is stored in
 538  *
 539  * Returns a pointer to the current tail of the message.
 540  */
 541 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 542 {
 543         return skb_tail_pointer(skb);
 544 }
 545
 546 /**
 547  * nlmsg_trim - Trim message to a mark
 548  * @skb: socket buffer the message is stored in
 549  * @mark: mark to trim to
 550  *
 551  * Trims the message to the provided mark. Returns -1.
 552  */
 553 static inline int nlmsg_trim(struct sk_buff *skb, const void *mark)
 554 {
 555         if (mark)
 556                 skb_trim(skb, (unsigned char *) mark - skb->data);
 557
 558         return -1;
 559 }
 560
 561 /**
 562  * nlmsg_cancel - Cancel construction of a netlink message
 563  * @skb: socket buffer the message is stored in
 564  * @nlh: netlink message header
 565  *
 566  * Removes the complete netlink message including all
 567  * attributes from the socket buffer again. Returns -1.
 568  */
 569 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 570 {
 571         return nlmsg_trim(skb, nlh);
 572 }
 573
 574 /**
 575  * nlmsg_free - free a netlink message
 576  * @skb: socket buffer of netlink message
 577  */
 578 static inline void nlmsg_free(struct sk_buff *skb)
 579 {
 580         kfree_skb(skb);
 581 }
 582
 583 /**
 584  * nlmsg_multicast - multicast a netlink message
 585  * @sk: netlink socket to spread messages to
 586  * @skb: netlink message as socket buffer
 587  * @pid: own netlink pid to avoid sending to yourself
 588  * @group: multicast group id
 589  * @flags: allocation flags
 590  */
 591 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 592                                   u32 pid, unsigned int group, gfp_t flags)
 593 {
 594         int err;
 595
 596         NETLINK_CB(skb).dst_group = group;
 597
 598         err = netlink_broadcast(sk, skb, pid, group, flags);
 599         if (err > 0)
 600                 err = 0;
 601
 602         return err;
 603 }
 604
 605 /**
 606  * nlmsg_unicast - unicast a netlink message
 607  * @sk: netlink socket to spread message to
 608  * @skb: netlink message as socket buffer
 609  * @pid: netlink pid of the destination socket
 610  */
 611 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 612 {
 613         int err;
 614
 615         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 616         if (err > 0)
 617                 err = 0;
 618
 619         return err;
 620 }
 621
 622 /**
 623  * nlmsg_for_each_msg - iterate over a stream of messages
 624  * @pos: loop counter, set to current message
 625  * @head: head of message stream
 626  * @len: length of message stream
 627  * @rem: initialized to len, holds bytes currently remaining in stream
 628  */
 629 #define nlmsg_for_each_msg(pos, head, len, rem) \
 630         for (pos = head, rem = len; \
 631              nlmsg_ok(pos, rem); \
 632              pos = nlmsg_next(pos, &(rem)))
 633
 634 /**************************************************************************
 635  * Netlink Attributes
 636  **************************************************************************/
 637
 638 /**
 639  * nla_attr_size - length of attribute not including padding
 640  * @payload: length of payload
 641  */
 642 static inline int nla_attr_size(int payload)
 643 {
 644         return NLA_HDRLEN + payload;
 645 }
 646
 647 /**
 648  * nla_total_size - total length of attribute including padding
 649  * @payload: length of payload
 650  */
 651 static inline int nla_total_size(int payload)
 652 {
 653         return NLA_ALIGN(nla_attr_size(payload));
 654 }
 655
 656 /**
 657  * nla_padlen - length of padding at the tail of attribute
 658  * @payload: length of payload
 659  */
 660 static inline int nla_padlen(int payload)
 661 {
 662         return nla_total_size(payload) - nla_attr_size(payload);
 663 }
 664
 665 /**
 666  * nla_data - head of payload
 667  * @nla: netlink attribute
 668  */
 669 static inline void *nla_data(const struct nlattr *nla)
 670 {
 671         return (char *) nla + NLA_HDRLEN;
 672 }
 673
 674 /**
 675  * nla_len - length of payload
 676  * @nla: netlink attribute
 677  */
 678 static inline int nla_len(const struct nlattr *nla)
 679 {
 680         return nla->nla_len - NLA_HDRLEN;
 681 }
 682
 683 /**
 684  * nla_ok - check if the netlink attribute fits into the remaining bytes
 685  * @nla: netlink attribute
 686  * @remaining: number of bytes remaining in attribute stream
 687  */
 688 static inline int nla_ok(const struct nlattr *nla, int remaining)
 689 {
 690         return remaining >= sizeof(*nla) &&
 691                nla->nla_len >= sizeof(*nla) &&
 692                nla->nla_len <= remaining;
 693 }
 694
 695 /**
 696  * nla_next - next netlink attribte in attribute stream
 697  * @nla: netlink attribute
 698  * @remaining: number of bytes remaining in attribute stream
 699  *
 700  * Returns the next netlink attribute in the attribute stream and
 701  * decrements remaining by the size of the current attribute.
 702  */
 703 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 704 {
 705         int totlen = NLA_ALIGN(nla->nla_len);
 706
 707         *remaining -= totlen;
 708         return (struct nlattr *) ((char *) nla + totlen);
 709 }
 710
 711 /**
 712  * nla_find_nested - find attribute in a set of nested attributes
 713  * @nla: attribute containing the nested attributes
 714  * @attrtype: type of attribute to look for
 715  *
 716  * Returns the first attribute which matches the specified type.
 717  */
 718 static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
 719 {
 720         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 721 }
 722
 723 /**
 724  * nla_parse_nested - parse nested attributes
 725  * @tb: destination array with maxtype+1 elements
 726  * @maxtype: maximum attribute type to be expected
 727  * @nla: attribute containing the nested attributes
 728  * @policy: validation policy
 729  *
 730  * See nla_parse()
 731  */
 732 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 733                                    struct nlattr *nla,
 734                                    struct nla_policy *policy)
 735 {
 736         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 737 }
 738 /**
 739  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 740  * @skb: socket buffer to add attribute to
 741  * @attrtype: attribute type
 742  * @value: numeric value
 743  */
 744 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 745 {
 746         return nla_put(skb, attrtype, sizeof(u8), &value);
 747 }
 748
 749 /**
 750  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 751  * @skb: socket buffer to add attribute to
 752  * @attrtype: attribute type
 753  * @value: numeric value
 754  */
 755 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 756 {
 757         return nla_put(skb, attrtype, sizeof(u16), &value);
 758 }
 759
 760 /**
 761  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 762  * @skb: socket buffer to add attribute to
 763  * @attrtype: attribute type
 764  * @value: numeric value
 765  */
 766 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 767 {
 768         return nla_put(skb, attrtype, sizeof(u32), &value);
 769 }
 770
 771 /**
 772  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 773  * @skb: socket buffer to add attribute to
 774  * @attrtype: attribute type
 775  * @value: numeric value
 776  */
 777 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 778 {
 779         return nla_put(skb, attrtype, sizeof(u64), &value);
 780 }
 781
 782 /**
 783  * nla_put_string - Add a string netlink attribute to a socket buffer
 784  * @skb: socket buffer to add attribute to
 785  * @attrtype: attribute type
 786  * @str: NUL terminated string
 787  */
 788 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 789                                  const char *str)
 790 {
 791         return nla_put(skb, attrtype, strlen(str) + 1, str);
 792 }
 793
 794 /**
 795  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 796  * @skb: socket buffer to add attribute to
 797  * @attrtype: attribute type
 798  */
 799 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 800 {
 801         return nla_put(skb, attrtype, 0, NULL);
 802 }
 803
 804 /**
 805  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 806  * @skb: socket buffer to add attribute to
 807  * @attrtype: attribute type
 808  * @jiffies: number of msecs in jiffies
 809  */
 810 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 811                                 unsigned long jiffies)
 812 {
 813         u64 tmp = jiffies_to_msecs(jiffies);
 814         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 815 }
 816
 817 #define NLA_PUT(skb, attrtype, attrlen, data) \
 818         do { \
 819                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 820                         goto nla_put_failure; \
 821         } while(0)
 822
 823 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 824         do { \
 825                 type __tmp = value; \
 826                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 827         } while(0)
 828
 829 #define NLA_PUT_U8(skb, attrtype, value) \
 830         NLA_PUT_TYPE(skb, u8, attrtype, value)
 831
 832 #define NLA_PUT_U16(skb, attrtype, value) \
 833         NLA_PUT_TYPE(skb, u16, attrtype, value)
 834
 835 #define NLA_PUT_LE16(skb, attrtype, value) \
 836         NLA_PUT_TYPE(skb, __le16, attrtype, value)
 837
 838 #define NLA_PUT_U32(skb, attrtype, value) \
 839         NLA_PUT_TYPE(skb, u32, attrtype, value)
 840
 841 #define NLA_PUT_BE32(skb, attrtype, value) \
 842         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 843
 844 #define NLA_PUT_U64(skb, attrtype, value) \
 845         NLA_PUT_TYPE(skb, u64, attrtype, value)
 846
 847 #define NLA_PUT_STRING(skb, attrtype, value) \
 848         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 849
 850 #define NLA_PUT_FLAG(skb, attrtype) \
 851         NLA_PUT(skb, attrtype, 0, NULL)
 852
 853 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 854         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 855
 856 /**
 857  * nla_get_u32 - return payload of u32 attribute
 858  * @nla: u32 netlink attribute
 859  */
 860 static inline u32 nla_get_u32(struct nlattr *nla)
 861 {
 862         return *(u32 *) nla_data(nla);
 863 }
 864
 865 /**
 866  * nla_get_be32 - return payload of __be32 attribute
 867  * @nla: __be32 netlink attribute
 868  */
 869 static inline __be32 nla_get_be32(struct nlattr *nla)
 870 {
 871         return *(__be32 *) nla_data(nla);
 872 }
 873
 874 /**
 875  * nla_get_u16 - return payload of u16 attribute
 876  * @nla: u16 netlink attribute
 877  */
 878 static inline u16 nla_get_u16(struct nlattr *nla)
 879 {
 880         return *(u16 *) nla_data(nla);
 881 }
 882
 883 /**
 884  * nla_get_le16 - return payload of __le16 attribute
 885  * @nla: __le16 netlink attribute
 886  */
 887 static inline __le16 nla_get_le16(struct nlattr *nla)
 888 {
 889         return *(__le16 *) nla_data(nla);
 890 }
 891
 892 /**
 893  * nla_get_u8 - return payload of u8 attribute
 894  * @nla: u8 netlink attribute
 895  */
 896 static inline u8 nla_get_u8(struct nlattr *nla)
 897 {
 898         return *(u8 *) nla_data(nla);
 899 }
 900
 901 /**
 902  * nla_get_u64 - return payload of u64 attribute
 903  * @nla: u64 netlink attribute
 904  */
 905 static inline u64 nla_get_u64(struct nlattr *nla)
 906 {
 907         u64 tmp;
 908
 909         nla_memcpy(&tmp, nla, sizeof(tmp));
 910
 911         return tmp;
 912 }
 913
 914 /**
 915  * nla_get_flag - return payload of flag attribute
 916  * @nla: flag netlink attribute
 917  */
 918 static inline int nla_get_flag(struct nlattr *nla)
 919 {
 920         return !!nla;
 921 }
 922
 923 /**
 924  * nla_get_msecs - return payload of msecs attribute
 925  * @nla: msecs netlink attribute
 926  *
 927  * Returns the number of milliseconds in jiffies.
 928  */
 929 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 930 {
 931         u64 msecs = nla_get_u64(nla);
 932
 933         return msecs_to_jiffies((unsigned long) msecs);
 934 }
 935
 936 /**
 937  * nla_nest_start - Start a new level of nested attributes
 938  * @skb: socket buffer to add attributes to
 939  * @attrtype: attribute type of container
 940  *
 941  * Returns the container attribute
 942  */
 943 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 944 {
 945         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
 946
 947         if (nla_put(skb, attrtype, 0, NULL) < 0)
 948                 return NULL;
 949
 950         return start;
 951 }
 952
 953 /**
 954  * nla_nest_end - Finalize nesting of attributes
 955  * @skb: socket buffer the attribtues are stored in
 956  * @start: container attribute
 957  *
 958  * Corrects the container attribute header to include the all
 959  * appeneded attributes.
 960  *
 961  * Returns the total data length of the skb.
 962  */
 963 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 964 {
 965         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
 966         return skb->len;
 967 }
 968
 969 /**
 970  * nla_nest_cancel - Cancel nesting of attributes
 971  * @skb: socket buffer the message is stored in
 972  * @start: container attribute
 973  *
 974  * Removes the container attribute and including all nested
 975  * attributes. Returns -1.
 976  */
 977 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 978 {
 979         return nlmsg_trim(skb, start);
 980 }
 981
 982 /**
 983  * nla_validate_nested - Validate a stream of nested attributes
 984  * @start: container attribute
 985  * @maxtype: maximum attribute type to be expected
 986  * @policy: validation policy
 987  *
 988  * Validates all attributes in the nested attribute stream against the
 989  * specified policy. Attributes with a type exceeding maxtype will be
 990  * ignored. See documenation of struct nla_policy for more details.
 991  *
 992  * Returns 0 on success or a negative error code.
 993  */
 994 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
 995                                       struct nla_policy *policy)
 996 {
 997         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
 998 }
 999
1000 /**
1001  * nla_for_each_attr - iterate over a stream of attributes
1002  * @pos: loop counter, set to current attribute
1003  * @head: head of attribute stream
1004  * @len: length of attribute stream
1005  * @rem: initialized to len, holds bytes currently remaining in stream
1006  */
1007 #define nla_for_each_attr(pos, head, len, rem) \
1008         for (pos = head, rem = len; \
1009              nla_ok(pos, rem); \
1010              pos = nla_next(pos, &(rem)))
1011
1012 /**
1013  * nla_for_each_nested - iterate over nested attributes
1014  * @pos: loop counter, set to current attribute
1015  * @nla: attribute containing the nested attributes
1016  * @rem: initialized to len, holds bytes currently remaining in stream
1017  */
1018 #define nla_for_each_nested(pos, nla, rem) \
1019         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1020
1021 #endif