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  * @size: maximum size of message
 504  * @flags: the type of memory to allocate.
 505  *
 506  * Use NLMSG_GOODSIZE if size isn't know and you need a good default size.
 507  */
 508 static inline struct sk_buff *nlmsg_new(int size, gfp_t flags)
 509 {
 510         return alloc_skb(size, flags);
 511 }
 512
 513 /**
 514  * nlmsg_end - Finalize a netlink message
 515  * @skb: socket buffer the message is stored in
 516  * @nlh: netlink message header
 517  *
 518  * Corrects the netlink message header to include the appeneded
 519  * attributes. Only necessary if attributes have been added to
 520  * the message.
 521  *
 522  * Returns the total data length of the skb.
 523  */
 524 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 525 {
 526         nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
 527
 528         return skb->len;
 529 }
 530
 531 /**
 532  * nlmsg_get_pos - return current position in netlink message
 533  * @skb: socket buffer the message is stored in
 534  *
 535  * Returns a pointer to the current tail of the message.
 536  */
 537 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 538 {
 539         return skb->tail;
 540 }
 541
 542 /**
 543  * nlmsg_trim - Trim message to a mark
 544  * @skb: socket buffer the message is stored in
 545  * @mark: mark to trim to
 546  *
 547  * Trims the message to the provided mark. Returns -1.
 548  */
 549 static inline int nlmsg_trim(struct sk_buff *skb, void *mark)
 550 {
 551         if (mark)
 552                 skb_trim(skb, (unsigned char *) mark - skb->data);
 553
 554         return -1;
 555 }
 556
 557 /**
 558  * nlmsg_cancel - Cancel construction of a netlink message
 559  * @skb: socket buffer the message is stored in
 560  * @nlh: netlink message header
 561  *
 562  * Removes the complete netlink message including all
 563  * attributes from the socket buffer again. Returns -1.
 564  */
 565 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 566 {
 567         return nlmsg_trim(skb, nlh);
 568 }
 569
 570 /**
 571  * nlmsg_free - free a netlink message
 572  * @skb: socket buffer of netlink message
 573  */
 574 static inline void nlmsg_free(struct sk_buff *skb)
 575 {
 576         kfree_skb(skb);
 577 }
 578
 579 /**
 580  * nlmsg_multicast - multicast a netlink message
 581  * @sk: netlink socket to spread messages to
 582  * @skb: netlink message as socket buffer
 583  * @pid: own netlink pid to avoid sending to yourself
 584  * @group: multicast group id
 585  * @flags: allocation flags
 586  */
 587 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 588                                   u32 pid, unsigned int group, gfp_t flags)
 589 {
 590         int err;
 591
 592         NETLINK_CB(skb).dst_group = group;
 593
 594         err = netlink_broadcast(sk, skb, pid, group, flags);
 595         if (err > 0)
 596                 err = 0;
 597
 598         return err;
 599 }
 600
 601 /**
 602  * nlmsg_unicast - unicast a netlink message
 603  * @sk: netlink socket to spread message to
 604  * @skb: netlink message as socket buffer
 605  * @pid: netlink pid of the destination socket
 606  */
 607 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 608 {
 609         int err;
 610
 611         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 612         if (err > 0)
 613                 err = 0;
 614
 615         return err;
 616 }
 617
 618 /**
 619  * nlmsg_for_each_msg - iterate over a stream of messages
 620  * @pos: loop counter, set to current message
 621  * @head: head of message stream
 622  * @len: length of message stream
 623  * @rem: initialized to len, holds bytes currently remaining in stream
 624  */
 625 #define nlmsg_for_each_msg(pos, head, len, rem) \
 626         for (pos = head, rem = len; \
 627              nlmsg_ok(pos, rem); \
 628              pos = nlmsg_next(pos, &(rem)))
 629
 630 /**************************************************************************
 631  * Netlink Attributes
 632  **************************************************************************/
 633
 634 /**
 635  * nla_attr_size - length of attribute not including padding
 636  * @payload: length of payload
 637  */
 638 static inline int nla_attr_size(int payload)
 639 {
 640         return NLA_HDRLEN + payload;
 641 }
 642
 643 /**
 644  * nla_total_size - total length of attribute including padding
 645  * @payload: length of payload
 646  */
 647 static inline int nla_total_size(int payload)
 648 {
 649         return NLA_ALIGN(nla_attr_size(payload));
 650 }
 651
 652 /**
 653  * nla_padlen - length of padding at the tail of attribute
 654  * @payload: length of payload
 655  */
 656 static inline int nla_padlen(int payload)
 657 {
 658         return nla_total_size(payload) - nla_attr_size(payload);
 659 }
 660
 661 /**
 662  * nla_data - head of payload
 663  * @nla: netlink attribute
 664  */
 665 static inline void *nla_data(const struct nlattr *nla)
 666 {
 667         return (char *) nla + NLA_HDRLEN;
 668 }
 669
 670 /**
 671  * nla_len - length of payload
 672  * @nla: netlink attribute
 673  */
 674 static inline int nla_len(const struct nlattr *nla)
 675 {
 676         return nla->nla_len - NLA_HDRLEN;
 677 }
 678
 679 /**
 680  * nla_ok - check if the netlink attribute fits into the remaining bytes
 681  * @nla: netlink attribute
 682  * @remaining: number of bytes remaining in attribute stream
 683  */
 684 static inline int nla_ok(const struct nlattr *nla, int remaining)
 685 {
 686         return remaining >= sizeof(*nla) &&
 687                nla->nla_len >= sizeof(*nla) &&
 688                nla->nla_len <= remaining;
 689 }
 690
 691 /**
 692  * nla_next - next netlink attribte in attribute stream
 693  * @nla: netlink attribute
 694  * @remaining: number of bytes remaining in attribute stream
 695  *
 696  * Returns the next netlink attribute in the attribute stream and
 697  * decrements remaining by the size of the current attribute.
 698  */
 699 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 700 {
 701         int totlen = NLA_ALIGN(nla->nla_len);
 702
 703         *remaining -= totlen;
 704         return (struct nlattr *) ((char *) nla + totlen);
 705 }
 706
 707 /**
 708  * nla_find_nested - find attribute in a set of nested attributes
 709  * @nla: attribute containing the nested attributes
 710  * @attrtype: type of attribute to look for
 711  *
 712  * Returns the first attribute which matches the specified type.
 713  */
 714 static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
 715 {
 716         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 717 }
 718
 719 /**
 720  * nla_parse_nested - parse nested attributes
 721  * @tb: destination array with maxtype+1 elements
 722  * @maxtype: maximum attribute type to be expected
 723  * @nla: attribute containing the nested attributes
 724  * @policy: validation policy
 725  *
 726  * See nla_parse()
 727  */
 728 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 729                                    struct nlattr *nla,
 730                                    struct nla_policy *policy)
 731 {
 732         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 733 }
 734 /**
 735  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 736  * @skb: socket buffer to add attribute to
 737  * @attrtype: attribute type
 738  * @value: numeric value
 739  */
 740 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 741 {
 742         return nla_put(skb, attrtype, sizeof(u8), &value);
 743 }
 744
 745 /**
 746  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 747  * @skb: socket buffer to add attribute to
 748  * @attrtype: attribute type
 749  * @value: numeric value
 750  */
 751 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 752 {
 753         return nla_put(skb, attrtype, sizeof(u16), &value);
 754 }
 755
 756 /**
 757  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 758  * @skb: socket buffer to add attribute to
 759  * @attrtype: attribute type
 760  * @value: numeric value
 761  */
 762 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 763 {
 764         return nla_put(skb, attrtype, sizeof(u32), &value);
 765 }
 766
 767 /**
 768  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 769  * @skb: socket buffer to add attribute to
 770  * @attrtype: attribute type
 771  * @value: numeric value
 772  */
 773 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 774 {
 775         return nla_put(skb, attrtype, sizeof(u64), &value);
 776 }
 777
 778 /**
 779  * nla_put_string - Add a string netlink attribute to a socket buffer
 780  * @skb: socket buffer to add attribute to
 781  * @attrtype: attribute type
 782  * @str: NUL terminated string
 783  */
 784 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 785                                  const char *str)
 786 {
 787         return nla_put(skb, attrtype, strlen(str) + 1, str);
 788 }
 789
 790 /**
 791  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 792  * @skb: socket buffer to add attribute to
 793  * @attrtype: attribute type
 794  */
 795 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 796 {
 797         return nla_put(skb, attrtype, 0, NULL);
 798 }
 799
 800 /**
 801  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 802  * @skb: socket buffer to add attribute to
 803  * @attrtype: attribute type
 804  * @jiffies: number of msecs in jiffies
 805  */
 806 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 807                                 unsigned long jiffies)
 808 {
 809         u64 tmp = jiffies_to_msecs(jiffies);
 810         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 811 }
 812
 813 #define NLA_PUT(skb, attrtype, attrlen, data) \
 814         do { \
 815                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 816                         goto nla_put_failure; \
 817         } while(0)
 818
 819 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 820         do { \
 821                 type __tmp = value; \
 822                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 823         } while(0)
 824
 825 #define NLA_PUT_U8(skb, attrtype, value) \
 826         NLA_PUT_TYPE(skb, u8, attrtype, value)
 827
 828 #define NLA_PUT_U16(skb, attrtype, value) \
 829         NLA_PUT_TYPE(skb, u16, attrtype, value)
 830
 831 #define NLA_PUT_U32(skb, attrtype, value) \
 832         NLA_PUT_TYPE(skb, u32, attrtype, value)
 833
 834 #define NLA_PUT_BE32(skb, attrtype, value) \
 835         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 836
 837 #define NLA_PUT_U64(skb, attrtype, value) \
 838         NLA_PUT_TYPE(skb, u64, attrtype, value)
 839
 840 #define NLA_PUT_STRING(skb, attrtype, value) \
 841         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 842
 843 #define NLA_PUT_FLAG(skb, attrtype) \
 844         NLA_PUT(skb, attrtype, 0, NULL)
 845
 846 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 847         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 848
 849 /**
 850  * nla_get_u32 - return payload of u32 attribute
 851  * @nla: u32 netlink attribute
 852  */
 853 static inline u32 nla_get_u32(struct nlattr *nla)
 854 {
 855         return *(u32 *) nla_data(nla);
 856 }
 857
 858 /**
 859  * nla_get_be32 - return payload of __be32 attribute
 860  * @nla: __be32 netlink attribute
 861  */
 862 static inline __be32 nla_get_be32(struct nlattr *nla)
 863 {
 864         return *(__be32 *) nla_data(nla);
 865 }
 866
 867 /**
 868  * nla_get_u16 - return payload of u16 attribute
 869  * @nla: u16 netlink attribute
 870  */
 871 static inline u16 nla_get_u16(struct nlattr *nla)
 872 {
 873         return *(u16 *) nla_data(nla);
 874 }
 875
 876 /**
 877  * nla_get_u8 - return payload of u8 attribute
 878  * @nla: u8 netlink attribute
 879  */
 880 static inline u8 nla_get_u8(struct nlattr *nla)
 881 {
 882         return *(u8 *) nla_data(nla);
 883 }
 884
 885 /**
 886  * nla_get_u64 - return payload of u64 attribute
 887  * @nla: u64 netlink attribute
 888  */
 889 static inline u64 nla_get_u64(struct nlattr *nla)
 890 {
 891         u64 tmp;
 892
 893         nla_memcpy(&tmp, nla, sizeof(tmp));
 894
 895         return tmp;
 896 }
 897
 898 /**
 899  * nla_get_flag - return payload of flag attribute
 900  * @nla: flag netlink attribute
 901  */
 902 static inline int nla_get_flag(struct nlattr *nla)
 903 {
 904         return !!nla;
 905 }
 906
 907 /**
 908  * nla_get_msecs - return payload of msecs attribute
 909  * @nla: msecs netlink attribute
 910  *
 911  * Returns the number of milliseconds in jiffies.
 912  */
 913 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 914 {
 915         u64 msecs = nla_get_u64(nla);
 916
 917         return msecs_to_jiffies((unsigned long) msecs);
 918 }
 919
 920 /**
 921  * nla_nest_start - Start a new level of nested attributes
 922  * @skb: socket buffer to add attributes to
 923  * @attrtype: attribute type of container
 924  *
 925  * Returns the container attribute
 926  */
 927 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 928 {
 929         struct nlattr *start = (struct nlattr *) skb->tail;
 930
 931         if (nla_put(skb, attrtype, 0, NULL) < 0)
 932                 return NULL;
 933
 934         return start;
 935 }
 936
 937 /**
 938  * nla_nest_end - Finalize nesting of attributes
 939  * @skb: socket buffer the attribtues are stored in
 940  * @start: container attribute
 941  *
 942  * Corrects the container attribute header to include the all
 943  * appeneded attributes.
 944  *
 945  * Returns the total data length of the skb.
 946  */
 947 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 948 {
 949         start->nla_len = skb->tail - (unsigned char *) start;
 950         return skb->len;
 951 }
 952
 953 /**
 954  * nla_nest_cancel - Cancel nesting of attributes
 955  * @skb: socket buffer the message is stored in
 956  * @start: container attribute
 957  *
 958  * Removes the container attribute and including all nested
 959  * attributes. Returns -1.
 960  */
 961 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 962 {
 963         return nlmsg_trim(skb, start);
 964 }
 965
 966 /**
 967  * nla_validate_nested - Validate a stream of nested attributes
 968  * @start: container attribute
 969  * @maxtype: maximum attribute type to be expected
 970  * @policy: validation policy
 971  *
 972  * Validates all attributes in the nested attribute stream against the
 973  * specified policy. Attributes with a type exceeding maxtype will be
 974  * ignored. See documenation of struct nla_policy for more details.
 975  *
 976  * Returns 0 on success or a negative error code.
 977  */
 978 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
 979                                       struct nla_policy *policy)
 980 {
 981         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
 982 }
 983
 984 /**
 985  * nla_for_each_attr - iterate over a stream of attributes
 986  * @pos: loop counter, set to current attribute
 987  * @head: head of attribute stream
 988  * @len: length of attribute stream
 989  * @rem: initialized to len, holds bytes currently remaining in stream
 990  */
 991 #define nla_for_each_attr(pos, head, len, rem) \
 992         for (pos = head, rem = len; \
 993              nla_ok(pos, rem); \
 994              pos = nla_next(pos, &(rem)))
 995
 996 /**
 997  * nla_for_each_nested - iterate over nested attributes
 998  * @pos: loop counter, set to current attribute
 999  * @nla: attribute containing the nested attributes
1000  * @rem: initialized to len, holds bytes currently remaining in stream
1001  */
1002 #define nla_for_each_nested(pos, nla, rem) \
1003         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1004
1005 #endif