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_TYPE_MAX,
 175 };
 176
 177 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 178
 179 /**
 180  * struct nla_policy - attribute validation policy
 181  * @type: Type of attribute or NLA_UNSPEC
 182  * @len: Type specific length of payload
 183  *
 184  * Policies are defined as arrays of this struct, the array must be
 185  * accessible by attribute type up to the highest identifier to be expected.
 186  *
 187  * Meaning of `len' field:
 188  *    NLA_STRING           Maximum length of string
 189  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 190  *    NLA_FLAG             Unused
 191  *    All other            Exact length of attribute payload
 192  *
 193  * Example:
 194  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 195  *      [ATTR_FOO] = { .type = NLA_U16 },
 196  *      [ATTR_BAR] = { .type = NLA_STRING, len = BARSIZ },
 197  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 198  * };
 199  */
 200 struct nla_policy {
 201         u16             type;
 202         u16             len;
 203 };
 204
 205 /**
 206  * struct nl_info - netlink source information
 207  * @nlh: Netlink message header of original request
 208  * @pid: Netlink PID of requesting application
 209  */
 210 struct nl_info {
 211         struct nlmsghdr         *nlh;
 212         u32                     pid;
 213 };
 214
 215 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 216                                           int (*cb)(struct sk_buff *,
 217                                                     struct nlmsghdr *));
 218 extern void             netlink_queue_skip(struct nlmsghdr *nlh,
 219                                            struct sk_buff *skb);
 220 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 221                                      u32 pid, unsigned int group, int report,
 222                                      gfp_t flags);
 223
 224 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 225                                      struct nla_policy *policy);
 226 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 227                                   struct nlattr *head, int len,
 228                                   struct nla_policy *policy);
 229 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 230 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 231                                     size_t dstsize);
 232 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 233 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 234                                    size_t size);
 235 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 236 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 237                                       int attrlen);
 238 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 239 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 240                                     int attrlen);
 241 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 242 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 243                                   int attrlen, const void *data);
 244 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 245                                         const void *data);
 246 extern int              nla_put(struct sk_buff *skb, int attrtype,
 247                                 int attrlen, const void *data);
 248 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 249                                       const void *data);
 250
 251 /**************************************************************************
 252  * Netlink Messages
 253  **************************************************************************/
 254
 255 /**
 256  * nlmsg_msg_size - length of netlink message not including padding
 257  * @payload: length of message payload
 258  */
 259 static inline int nlmsg_msg_size(int payload)
 260 {
 261         return NLMSG_HDRLEN + payload;
 262 }
 263
 264 /**
 265  * nlmsg_total_size - length of netlink message including padding
 266  * @payload: length of message payload
 267  */
 268 static inline int nlmsg_total_size(int payload)
 269 {
 270         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 271 }
 272
 273 /**
 274  * nlmsg_padlen - length of padding at the message's tail
 275  * @payload: length of message payload
 276  */
 277 static inline int nlmsg_padlen(int payload)
 278 {
 279         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 280 }
 281
 282 /**
 283  * nlmsg_data - head of message payload
 284  * @nlh: netlink messsage header
 285  */
 286 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 287 {
 288         return (unsigned char *) nlh + NLMSG_HDRLEN;
 289 }
 290
 291 /**
 292  * nlmsg_len - length of message payload
 293  * @nlh: netlink message header
 294  */
 295 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 296 {
 297         return nlh->nlmsg_len - NLMSG_HDRLEN;
 298 }
 299
 300 /**
 301  * nlmsg_attrdata - head of attributes data
 302  * @nlh: netlink message header
 303  * @hdrlen: length of family specific header
 304  */
 305 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 306                                             int hdrlen)
 307 {
 308         unsigned char *data = nlmsg_data(nlh);
 309         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 310 }
 311
 312 /**
 313  * nlmsg_attrlen - length of attributes data
 314  * @nlh: netlink message header
 315  * @hdrlen: length of family specific header
 316  */
 317 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 318 {
 319         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 320 }
 321
 322 /**
 323  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 324  * @nlh: netlink message header
 325  * @remaining: number of bytes remaining in message stream
 326  */
 327 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 328 {
 329         return (remaining >= sizeof(struct nlmsghdr) &&
 330                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 331                 nlh->nlmsg_len <= remaining);
 332 }
 333
 334 /**
 335  * nlmsg_next - next netlink message in message stream
 336  * @nlh: netlink message header
 337  * @remaining: number of bytes remaining in message stream
 338  *
 339  * Returns the next netlink message in the message stream and
 340  * decrements remaining by the size of the current message.
 341  */
 342 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 343 {
 344         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 345
 346         *remaining -= totlen;
 347
 348         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 349 }
 350
 351 /**
 352  * nlmsg_parse - parse attributes of a netlink message
 353  * @nlh: netlink message header
 354  * @hdrlen: length of family specific header
 355  * @tb: destination array with maxtype+1 elements
 356  * @maxtype: maximum attribute type to be expected
 357  * @policy: validation policy
 358  *
 359  * See nla_parse()
 360  */
 361 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 362                               struct nlattr *tb[], int maxtype,
 363                               struct nla_policy *policy)
 364 {
 365         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 366                 return -EINVAL;
 367
 368         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 369                          nlmsg_attrlen(nlh, hdrlen), policy);
 370 }
 371
 372 /**
 373  * nlmsg_find_attr - find a specific attribute in a netlink message
 374  * @nlh: netlink message header
 375  * @hdrlen: length of familiy specific header
 376  * @attrtype: type of attribute to look for
 377  *
 378  * Returns the first attribute which matches the specified type.
 379  */
 380 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 381                                              int hdrlen, int attrtype)
 382 {
 383         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 384                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 385 }
 386
 387 /**
 388  * nlmsg_validate - validate a netlink message including attributes
 389  * @nlh: netlinket message header
 390  * @hdrlen: length of familiy specific header
 391  * @maxtype: maximum attribute type to be expected
 392  * @policy: validation policy
 393  */
 394 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 395                                  struct nla_policy *policy)
 396 {
 397         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 398                 return -EINVAL;
 399
 400         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 401                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 402 }
 403
 404 /**
 405  * nlmsg_report - need to report back to application?
 406  * @nlh: netlink message header
 407  *
 408  * Returns 1 if a report back to the application is requested.
 409  */
 410 static inline int nlmsg_report(struct nlmsghdr *nlh)
 411 {
 412         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 413 }
 414
 415 /**
 416  * nlmsg_for_each_attr - iterate over a stream of attributes
 417  * @pos: loop counter, set to current attribute
 418  * @nlh: netlink message header
 419  * @hdrlen: length of familiy specific header
 420  * @rem: initialized to len, holds bytes currently remaining in stream
 421  */
 422 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 423         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 424                           nlmsg_attrlen(nlh, hdrlen), rem)
 425
 426 #if 0
 427 /* FIXME: Enable once all users have been converted */
 428
 429 /**
 430  * __nlmsg_put - Add a new netlink message to an skb
 431  * @skb: socket buffer to store message in
 432  * @pid: netlink process id
 433  * @seq: sequence number of message
 434  * @type: message type
 435  * @payload: length of message payload
 436  * @flags: message flags
 437  *
 438  * The caller is responsible to ensure that the skb provides enough
 439  * tailroom for both the netlink header and payload.
 440  */
 441 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 442                                            u32 seq, int type, int payload,
 443                                            int flags)
 444 {
 445         struct nlmsghdr *nlh;
 446
 447         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 448         nlh->nlmsg_type = type;
 449         nlh->nlmsg_len = nlmsg_msg_size(payload);
 450         nlh->nlmsg_flags = flags;
 451         nlh->nlmsg_pid = pid;
 452         nlh->nlmsg_seq = seq;
 453
 454         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 455                nlmsg_padlen(payload));
 456
 457         return nlh;
 458 }
 459 #endif
 460
 461 /**
 462  * nlmsg_put - Add a new netlink message to an skb
 463  * @skb: socket buffer to store message in
 464  * @pid: netlink process id
 465  * @seq: sequence number of message
 466  * @type: message type
 467  * @payload: length of message payload
 468  * @flags: message flags
 469  *
 470  * Returns NULL if the tailroom of the skb is insufficient to store
 471  * the message header and payload.
 472  */
 473 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 474                                          int type, int payload, int flags)
 475 {
 476         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 477                 return NULL;
 478
 479         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 480 }
 481
 482 /**
 483  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 484  * @skb: socket buffer to store message in
 485  * @cb: netlink callback
 486  * @type: message type
 487  * @payload: length of message payload
 488  * @flags: message flags
 489  *
 490  * Returns NULL if the tailroom of the skb is insufficient to store
 491  * the message header and payload.
 492  */
 493 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 494                                                 struct netlink_callback *cb,
 495                                                 int type, int payload,
 496                                                 int flags)
 497 {
 498         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 499                          type, payload, flags);
 500 }
 501
 502 /**
 503  * nlmsg_new - Allocate a new netlink message
 504  * @payload: size of the message payload
 505  * @flags: the type of memory to allocate.
 506  *
 507  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 508  * and a good default is needed.
 509  */
 510 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 511 {
 512         return alloc_skb(nlmsg_total_size(payload), flags);
 513 }
 514
 515 /**
 516  * nlmsg_end - Finalize a netlink message
 517  * @skb: socket buffer the message is stored in
 518  * @nlh: netlink message header
 519  *
 520  * Corrects the netlink message header to include the appeneded
 521  * attributes. Only necessary if attributes have been added to
 522  * the message.
 523  *
 524  * Returns the total data length of the skb.
 525  */
 526 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 527 {
 528         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 529
 530         return skb->len;
 531 }
 532
 533 /**
 534  * nlmsg_get_pos - return current position in netlink message
 535  * @skb: socket buffer the message is stored in
 536  *
 537  * Returns a pointer to the current tail of the message.
 538  */
 539 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 540 {
 541         return skb_tail_pointer(skb);
 542 }
 543
 544 /**
 545  * nlmsg_trim - Trim message to a mark
 546  * @skb: socket buffer the message is stored in
 547  * @mark: mark to trim to
 548  *
 549  * Trims the message to the provided mark. Returns -1.
 550  */
 551 static inline int nlmsg_trim(struct sk_buff *skb, const void *mark)
 552 {
 553         if (mark)
 554                 skb_trim(skb, (unsigned char *) mark - skb->data);
 555
 556         return -1;
 557 }
 558
 559 /**
 560  * nlmsg_cancel - Cancel construction of a netlink message
 561  * @skb: socket buffer the message is stored in
 562  * @nlh: netlink message header
 563  *
 564  * Removes the complete netlink message including all
 565  * attributes from the socket buffer again. Returns -1.
 566  */
 567 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 568 {
 569         return nlmsg_trim(skb, nlh);
 570 }
 571
 572 /**
 573  * nlmsg_free - free a netlink message
 574  * @skb: socket buffer of netlink message
 575  */
 576 static inline void nlmsg_free(struct sk_buff *skb)
 577 {
 578         kfree_skb(skb);
 579 }
 580
 581 /**
 582  * nlmsg_multicast - multicast a netlink message
 583  * @sk: netlink socket to spread messages to
 584  * @skb: netlink message as socket buffer
 585  * @pid: own netlink pid to avoid sending to yourself
 586  * @group: multicast group id
 587  * @flags: allocation flags
 588  */
 589 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 590                                   u32 pid, unsigned int group, gfp_t flags)
 591 {
 592         int err;
 593
 594         NETLINK_CB(skb).dst_group = group;
 595
 596         err = netlink_broadcast(sk, skb, pid, group, flags);
 597         if (err > 0)
 598                 err = 0;
 599
 600         return err;
 601 }
 602
 603 /**
 604  * nlmsg_unicast - unicast a netlink message
 605  * @sk: netlink socket to spread message to
 606  * @skb: netlink message as socket buffer
 607  * @pid: netlink pid of the destination socket
 608  */
 609 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 610 {
 611         int err;
 612
 613         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 614         if (err > 0)
 615                 err = 0;
 616
 617         return err;
 618 }
 619
 620 /**
 621  * nlmsg_for_each_msg - iterate over a stream of messages
 622  * @pos: loop counter, set to current message
 623  * @head: head of message stream
 624  * @len: length of message stream
 625  * @rem: initialized to len, holds bytes currently remaining in stream
 626  */
 627 #define nlmsg_for_each_msg(pos, head, len, rem) \
 628         for (pos = head, rem = len; \
 629              nlmsg_ok(pos, rem); \
 630              pos = nlmsg_next(pos, &(rem)))
 631
 632 /**************************************************************************
 633  * Netlink Attributes
 634  **************************************************************************/
 635
 636 /**
 637  * nla_attr_size - length of attribute not including padding
 638  * @payload: length of payload
 639  */
 640 static inline int nla_attr_size(int payload)
 641 {
 642         return NLA_HDRLEN + payload;
 643 }
 644
 645 /**
 646  * nla_total_size - total length of attribute including padding
 647  * @payload: length of payload
 648  */
 649 static inline int nla_total_size(int payload)
 650 {
 651         return NLA_ALIGN(nla_attr_size(payload));
 652 }
 653
 654 /**
 655  * nla_padlen - length of padding at the tail of attribute
 656  * @payload: length of payload
 657  */
 658 static inline int nla_padlen(int payload)
 659 {
 660         return nla_total_size(payload) - nla_attr_size(payload);
 661 }
 662
 663 /**
 664  * nla_data - head of payload
 665  * @nla: netlink attribute
 666  */
 667 static inline void *nla_data(const struct nlattr *nla)
 668 {
 669         return (char *) nla + NLA_HDRLEN;
 670 }
 671
 672 /**
 673  * nla_len - length of payload
 674  * @nla: netlink attribute
 675  */
 676 static inline int nla_len(const struct nlattr *nla)
 677 {
 678         return nla->nla_len - NLA_HDRLEN;
 679 }
 680
 681 /**
 682  * nla_ok - check if the netlink attribute fits into the remaining bytes
 683  * @nla: netlink attribute
 684  * @remaining: number of bytes remaining in attribute stream
 685  */
 686 static inline int nla_ok(const struct nlattr *nla, int remaining)
 687 {
 688         return remaining >= sizeof(*nla) &&
 689                nla->nla_len >= sizeof(*nla) &&
 690                nla->nla_len <= remaining;
 691 }
 692
 693 /**
 694  * nla_next - next netlink attribte in attribute stream
 695  * @nla: netlink attribute
 696  * @remaining: number of bytes remaining in attribute stream
 697  *
 698  * Returns the next netlink attribute in the attribute stream and
 699  * decrements remaining by the size of the current attribute.
 700  */
 701 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 702 {
 703         int totlen = NLA_ALIGN(nla->nla_len);
 704
 705         *remaining -= totlen;
 706         return (struct nlattr *) ((char *) nla + totlen);
 707 }
 708
 709 /**
 710  * nla_find_nested - find attribute in a set of nested attributes
 711  * @nla: attribute containing the nested attributes
 712  * @attrtype: type of attribute to look for
 713  *
 714  * Returns the first attribute which matches the specified type.
 715  */
 716 static inline struct nlattr *nla_find_nested(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                                    struct nlattr *nla,
 732                                    struct nla_policy *policy)
 733 {
 734         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 735 }
 736 /**
 737  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 738  * @skb: socket buffer to add attribute to
 739  * @attrtype: attribute type
 740  * @value: numeric value
 741  */
 742 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 743 {
 744         return nla_put(skb, attrtype, sizeof(u8), &value);
 745 }
 746
 747 /**
 748  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 749  * @skb: socket buffer to add attribute to
 750  * @attrtype: attribute type
 751  * @value: numeric value
 752  */
 753 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 754 {
 755         return nla_put(skb, attrtype, sizeof(u16), &value);
 756 }
 757
 758 /**
 759  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 760  * @skb: socket buffer to add attribute to
 761  * @attrtype: attribute type
 762  * @value: numeric value
 763  */
 764 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 765 {
 766         return nla_put(skb, attrtype, sizeof(u32), &value);
 767 }
 768
 769 /**
 770  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 771  * @skb: socket buffer to add attribute to
 772  * @attrtype: attribute type
 773  * @value: numeric value
 774  */
 775 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 776 {
 777         return nla_put(skb, attrtype, sizeof(u64), &value);
 778 }
 779
 780 /**
 781  * nla_put_string - Add a string netlink attribute to a socket buffer
 782  * @skb: socket buffer to add attribute to
 783  * @attrtype: attribute type
 784  * @str: NUL terminated string
 785  */
 786 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 787                                  const char *str)
 788 {
 789         return nla_put(skb, attrtype, strlen(str) + 1, str);
 790 }
 791
 792 /**
 793  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 794  * @skb: socket buffer to add attribute to
 795  * @attrtype: attribute type
 796  */
 797 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 798 {
 799         return nla_put(skb, attrtype, 0, NULL);
 800 }
 801
 802 /**
 803  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 804  * @skb: socket buffer to add attribute to
 805  * @attrtype: attribute type
 806  * @jiffies: number of msecs in jiffies
 807  */
 808 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 809                                 unsigned long jiffies)
 810 {
 811         u64 tmp = jiffies_to_msecs(jiffies);
 812         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 813 }
 814
 815 #define NLA_PUT(skb, attrtype, attrlen, data) \
 816         do { \
 817                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 818                         goto nla_put_failure; \
 819         } while(0)
 820
 821 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 822         do { \
 823                 type __tmp = value; \
 824                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 825         } while(0)
 826
 827 #define NLA_PUT_U8(skb, attrtype, value) \
 828         NLA_PUT_TYPE(skb, u8, attrtype, value)
 829
 830 #define NLA_PUT_U16(skb, attrtype, value) \
 831         NLA_PUT_TYPE(skb, u16, attrtype, value)
 832
 833 #define NLA_PUT_LE16(skb, attrtype, value) \
 834         NLA_PUT_TYPE(skb, __le16, attrtype, value)
 835
 836 #define NLA_PUT_U32(skb, attrtype, value) \
 837         NLA_PUT_TYPE(skb, u32, attrtype, value)
 838
 839 #define NLA_PUT_BE32(skb, attrtype, value) \
 840         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 841
 842 #define NLA_PUT_U64(skb, attrtype, value) \
 843         NLA_PUT_TYPE(skb, u64, attrtype, value)
 844
 845 #define NLA_PUT_STRING(skb, attrtype, value) \
 846         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 847
 848 #define NLA_PUT_FLAG(skb, attrtype) \
 849         NLA_PUT(skb, attrtype, 0, NULL)
 850
 851 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 852         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 853
 854 /**
 855  * nla_get_u32 - return payload of u32 attribute
 856  * @nla: u32 netlink attribute
 857  */
 858 static inline u32 nla_get_u32(struct nlattr *nla)
 859 {
 860         return *(u32 *) nla_data(nla);
 861 }
 862
 863 /**
 864  * nla_get_be32 - return payload of __be32 attribute
 865  * @nla: __be32 netlink attribute
 866  */
 867 static inline __be32 nla_get_be32(struct nlattr *nla)
 868 {
 869         return *(__be32 *) nla_data(nla);
 870 }
 871
 872 /**
 873  * nla_get_u16 - return payload of u16 attribute
 874  * @nla: u16 netlink attribute
 875  */
 876 static inline u16 nla_get_u16(struct nlattr *nla)
 877 {
 878         return *(u16 *) nla_data(nla);
 879 }
 880
 881 /**
 882  * nla_get_le16 - return payload of __le16 attribute
 883  * @nla: __le16 netlink attribute
 884  */
 885 static inline __le16 nla_get_le16(struct nlattr *nla)
 886 {
 887         return *(__le16 *) nla_data(nla);
 888 }
 889
 890 /**
 891  * nla_get_u8 - return payload of u8 attribute
 892  * @nla: u8 netlink attribute
 893  */
 894 static inline u8 nla_get_u8(struct nlattr *nla)
 895 {
 896         return *(u8 *) nla_data(nla);
 897 }
 898
 899 /**
 900  * nla_get_u64 - return payload of u64 attribute
 901  * @nla: u64 netlink attribute
 902  */
 903 static inline u64 nla_get_u64(struct nlattr *nla)
 904 {
 905         u64 tmp;
 906
 907         nla_memcpy(&tmp, nla, sizeof(tmp));
 908
 909         return tmp;
 910 }
 911
 912 /**
 913  * nla_get_flag - return payload of flag attribute
 914  * @nla: flag netlink attribute
 915  */
 916 static inline int nla_get_flag(struct nlattr *nla)
 917 {
 918         return !!nla;
 919 }
 920
 921 /**
 922  * nla_get_msecs - return payload of msecs attribute
 923  * @nla: msecs netlink attribute
 924  *
 925  * Returns the number of milliseconds in jiffies.
 926  */
 927 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 928 {
 929         u64 msecs = nla_get_u64(nla);
 930
 931         return msecs_to_jiffies((unsigned long) msecs);
 932 }
 933
 934 /**
 935  * nla_nest_start - Start a new level of nested attributes
 936  * @skb: socket buffer to add attributes to
 937  * @attrtype: attribute type of container
 938  *
 939  * Returns the container attribute
 940  */
 941 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 942 {
 943         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
 944
 945         if (nla_put(skb, attrtype, 0, NULL) < 0)
 946                 return NULL;
 947
 948         return start;
 949 }
 950
 951 /**
 952  * nla_nest_end - Finalize nesting of attributes
 953  * @skb: socket buffer the attribtues are stored in
 954  * @start: container attribute
 955  *
 956  * Corrects the container attribute header to include the all
 957  * appeneded attributes.
 958  *
 959  * Returns the total data length of the skb.
 960  */
 961 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 962 {
 963         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
 964         return skb->len;
 965 }
 966
 967 /**
 968  * nla_nest_cancel - Cancel nesting of attributes
 969  * @skb: socket buffer the message is stored in
 970  * @start: container attribute
 971  *
 972  * Removes the container attribute and including all nested
 973  * attributes. Returns -1.
 974  */
 975 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 976 {
 977         return nlmsg_trim(skb, start);
 978 }
 979
 980 /**
 981  * nla_validate_nested - Validate a stream of nested attributes
 982  * @start: container attribute
 983  * @maxtype: maximum attribute type to be expected
 984  * @policy: validation policy
 985  *
 986  * Validates all attributes in the nested attribute stream against the
 987  * specified policy. Attributes with a type exceeding maxtype will be
 988  * ignored. See documenation of struct nla_policy for more details.
 989  *
 990  * Returns 0 on success or a negative error code.
 991  */
 992 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
 993                                       struct nla_policy *policy)
 994 {
 995         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
 996 }
 997
 998 /**
 999  * nla_for_each_attr - iterate over a stream of attributes
1000  * @pos: loop counter, set to current attribute
1001  * @head: head of attribute stream
1002  * @len: length of attribute stream
1003  * @rem: initialized to len, holds bytes currently remaining in stream
1004  */
1005 #define nla_for_each_attr(pos, head, len, rem) \
1006         for (pos = head, rem = len; \
1007              nla_ok(pos, rem); \
1008              pos = nla_next(pos, &(rem)))
1009
1010 /**
1011  * nla_for_each_nested - iterate over nested attributes
1012  * @pos: loop counter, set to current attribute
1013  * @nla: attribute containing the nested attributes
1014  * @rem: initialized to len, holds bytes currently remaining in stream
1015  */
1016 #define nla_for_each_nested(pos, nla, rem) \
1017         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1018
1019 #endif