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_cancel()                     cancel message construction
  39  *   nlmsg_free()                       free a netlink message
  40  *
  41  * Message Sending:
  42  *   nlmsg_multicast()                  multicast message to several groups
  43  *   nlmsg_unicast()                    unicast a message to a single socket
  44  *
  45  * Message Length Calculations:
  46  *   nlmsg_msg_size(payload)            length of message w/o padding
  47  *   nlmsg_total_size(payload)          length of message w/ padding
  48  *   nlmsg_padlen(payload)              length of padding at tail
  49  *
  50  * Message Payload Access:
  51  *   nlmsg_data(nlh)                    head of message payload
  52  *   nlmsg_len(nlh)                     length of message payload
  53  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  54  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  55  *
  56  * Message Parsing:
  57  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  58  *   nlmsg_next(nlh, remaining)         get next netlink message
  59  *   nlmsg_parse()                      parse attributes of a message
  60  *   nlmsg_find_attr()                  find an attribute in a message
  61  *   nlmsg_for_each_msg()               loop over all messages
  62  *   nlmsg_validate()                   validate netlink message incl. attrs
  63  *   nlmsg_for_each_attr()              loop over all attributes
  64  *
  65  * ------------------------------------------------------------------------
  66  *                          Attributes Interface
  67  * ------------------------------------------------------------------------
  68  *
  69  * Attribute Format:
  70  *    <------- nla_total_size(payload) ------->
  71  *    <---- nla_attr_size(payload) ----->
  72  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  73  *   |  Header  | Pad |     Payload      | Pad |  Header
  74  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  75  *                     <- nla_len(nla) ->      ^
  76  *   nla_data(nla)----^                        |
  77  *   nla_next(nla)-----------------------------'
  78  *
  79  * Data Structures:
  80  *   struct nlattr                      netlink attribtue header
  81  *
  82  * Attribute Construction:
  83  *   nla_reserve(skb, type, len)        reserve skb tailroom for an attribute
  84  *   nla_put(skb, type, len, data)      add attribute to skb
  85  *
  86  * Attribute Construction for Basic Types:
  87  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  88  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  89  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
  90  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
  91  *   nla_put_string(skb, type, str)     add string attribute to skb
  92  *   nla_put_flag(skb, type)            add flag attribute to skb
  93  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
  94  *
  95  * Exceptions Based Attribute Construction:
  96  *   NLA_PUT(skb, type, len, data)      add attribute to skb
  97  *   NLA_PUT_U8(skb, type, value)       add u8 attribute to skb
  98  *   NLA_PUT_U16(skb, type, value)      add u16 attribute to skb
  99  *   NLA_PUT_U32(skb, type, value)      add u32 attribute to skb
 100  *   NLA_PUT_U64(skb, type, value)      add u64 attribute to skb
 101  *   NLA_PUT_STRING(skb, type, str)     add string attribute to skb
 102  *   NLA_PUT_FLAG(skb, type)            add flag attribute to skb
 103  *   NLA_PUT_MSECS(skb, type, jiffies)  add msecs attribute to skb
 104  *
 105  *   The meaning of these functions is equal to their lower case
 106  *   variants but they jump to the label nla_put_failure in case
 107  *   of a failure.
 108  *
 109  * Nested Attributes Construction:
 110  *   nla_nest_start(skb, type)          start a nested attribute
 111  *   nla_nest_end(skb, nla)             finalize a nested attribute
 112  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 113  *
 114  * Attribute Length Calculations:
 115  *   nla_attr_size(payload)             length of attribute w/o padding
 116  *   nla_total_size(payload)            length of attribute w/ padding
 117  *   nla_padlen(payload)                length of padding
 118  *
 119  * Attribute Payload Access:
 120  *   nla_data(nla)                      head of attribute payload
 121  *   nla_len(nla)                       length of attribute payload
 122  *
 123  * Attribute Payload Access for Basic Types:
 124  *   nla_get_u8(nla)                    get payload for a u8 attribute
 125  *   nla_get_u16(nla)                   get payload for a u16 attribute
 126  *   nla_get_u32(nla)                   get payload for a u32 attribute
 127  *   nla_get_u64(nla)                   get payload for a u64 attribute
 128  *   nla_get_flag(nla)                  return 1 if flag is true
 129  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 130  *
 131  * Attribute Misc:
 132  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 133  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 134  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 135  *   nla_strcmp(nla, str)               compare attribute with string
 136  *
 137  * Attribute Parsing:
 138  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 139  *   nla_next(nla, remaining)           get next netlink attribute
 140  *   nla_validate()                     validate a stream of attributes
 141  *   nla_find()                         find attribute in stream of attributes
 142  *   nla_parse()                        parse and validate stream of attrs
 143  *   nla_parse_nested()                 parse nested attribuets
 144  *   nla_for_each_attr()                loop over all attributes
 145  *=========================================================================
 146  */
 147
 148  /**
 149   * Standard attribute types to specify validation policy
 150   */
 151 enum {
 152         NLA_UNSPEC,
 153         NLA_U8,
 154         NLA_U16,
 155         NLA_U32,
 156         NLA_U64,
 157         NLA_STRING,
 158         NLA_FLAG,
 159         NLA_MSECS,
 160         NLA_NESTED,
 161         __NLA_TYPE_MAX,
 162 };
 163
 164 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 165
 166 /**
 167  * struct nla_policy - attribute validation policy
 168  * @type: Type of attribute or NLA_UNSPEC
 169  * @minlen: Minimal length of payload required to be available
 170  *
 171  * Policies are defined as arrays of this struct, the array must be
 172  * accessible by attribute type up to the highest identifier to be expected.
 173  *
 174  * Example:
 175  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 176  *      [ATTR_FOO] = { .type = NLA_U16 },
 177  *      [ATTR_BAR] = { .type = NLA_STRING },
 178  *      [ATTR_BAZ] = { .minlen = sizeof(struct mystruct) },
 179  * };
 180  */
 181 struct nla_policy {
 182         u16             type;
 183         u16             minlen;
 184 };
 185
 186 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 187                                           int (*cb)(struct sk_buff *,
 188                                                     struct nlmsghdr *, int *));
 189 extern void             netlink_queue_skip(struct nlmsghdr *nlh,
 190                                            struct sk_buff *skb);
 191
 192 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 193                                      struct nla_policy *policy);
 194 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 195                                   struct nlattr *head, int len,
 196                                   struct nla_policy *policy);
 197 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 198 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 199                                     size_t dstsize);
 200 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 201 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 202                                    size_t size);
 203 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 204 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 205                                       int attrlen);
 206 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 207                                     int attrlen);
 208 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 209                                   int attrlen, const void *data);
 210 extern int              nla_put(struct sk_buff *skb, int attrtype,
 211                                 int attrlen, const void *data);
 212
 213 /**************************************************************************
 214  * Netlink Messages
 215  **************************************************************************/
 216
 217 /**
 218  * nlmsg_msg_size - length of netlink message not including padding
 219  * @payload: length of message payload
 220  */
 221 static inline int nlmsg_msg_size(int payload)
 222 {
 223         return NLMSG_HDRLEN + payload;
 224 }
 225
 226 /**
 227  * nlmsg_total_size - length of netlink message including padding
 228  * @payload: length of message payload
 229  */
 230 static inline int nlmsg_total_size(int payload)
 231 {
 232         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 233 }
 234
 235 /**
 236  * nlmsg_padlen - length of padding at the message's tail
 237  * @payload: length of message payload
 238  */
 239 static inline int nlmsg_padlen(int payload)
 240 {
 241         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 242 }
 243
 244 /**
 245  * nlmsg_data - head of message payload
 246  * @nlh: netlink messsage header
 247  */
 248 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 249 {
 250         return (unsigned char *) nlh + NLMSG_HDRLEN;
 251 }
 252
 253 /**
 254  * nlmsg_len - length of message payload
 255  * @nlh: netlink message header
 256  */
 257 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 258 {
 259         return nlh->nlmsg_len - NLMSG_HDRLEN;
 260 }
 261
 262 /**
 263  * nlmsg_attrdata - head of attributes data
 264  * @nlh: netlink message header
 265  * @hdrlen: length of family specific header
 266  */
 267 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 268                                             int hdrlen)
 269 {
 270         unsigned char *data = nlmsg_data(nlh);
 271         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 272 }
 273
 274 /**
 275  * nlmsg_attrlen - length of attributes data
 276  * @nlh: netlink message header
 277  * @hdrlen: length of family specific header
 278  */
 279 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 280 {
 281         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 282 }
 283
 284 /**
 285  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 286  * @nlh: netlink message header
 287  * @remaining: number of bytes remaining in message stream
 288  */
 289 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 290 {
 291         return (remaining >= sizeof(struct nlmsghdr) &&
 292                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 293                 nlh->nlmsg_len <= remaining);
 294 }
 295
 296 /**
 297  * nlmsg_next - next netlink message in message stream
 298  * @nlh: netlink message header
 299  * @remaining: number of bytes remaining in message stream
 300  *
 301  * Returns the next netlink message in the message stream and
 302  * decrements remaining by the size of the current message.
 303  */
 304 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 305 {
 306         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 307
 308         *remaining -= totlen;
 309
 310         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 311 }
 312
 313 /**
 314  * nlmsg_parse - parse attributes of a netlink message
 315  * @nlh: netlink message header
 316  * @hdrlen: length of family specific header
 317  * @tb: destination array with maxtype+1 elements
 318  * @maxtype: maximum attribute type to be expected
 319  * @policy: validation policy
 320  *
 321  * See nla_parse()
 322  */
 323 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 324                               struct nlattr *tb[], int maxtype,
 325                               struct nla_policy *policy)
 326 {
 327         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 328                 return -EINVAL;
 329
 330         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 331                          nlmsg_attrlen(nlh, hdrlen), policy);
 332 }
 333
 334 /**
 335  * nlmsg_find_attr - find a specific attribute in a netlink message
 336  * @nlh: netlink message header
 337  * @hdrlen: length of familiy specific header
 338  * @attrtype: type of attribute to look for
 339  *
 340  * Returns the first attribute which matches the specified type.
 341  */
 342 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 343                                              int hdrlen, int attrtype)
 344 {
 345         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 346                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 347 }
 348
 349 /**
 350  * nlmsg_validate - validate a netlink message including attributes
 351  * @nlh: netlinket message header
 352  * @hdrlen: length of familiy specific header
 353  * @maxtype: maximum attribute type to be expected
 354  * @policy: validation policy
 355  */
 356 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 357                                  struct nla_policy *policy)
 358 {
 359         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 360                 return -EINVAL;
 361
 362         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 363                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 364 }
 365
 366 /**
 367  * nlmsg_for_each_attr - iterate over a stream of attributes
 368  * @pos: loop counter, set to current attribute
 369  * @nlh: netlink message header
 370  * @hdrlen: length of familiy specific header
 371  * @rem: initialized to len, holds bytes currently remaining in stream
 372  */
 373 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 374         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 375                           nlmsg_attrlen(nlh, hdrlen), rem)
 376
 377 #if 0
 378 /* FIXME: Enable once all users have been converted */
 379
 380 /**
 381  * __nlmsg_put - Add a new netlink message to an skb
 382  * @skb: socket buffer to store message in
 383  * @pid: netlink process id
 384  * @seq: sequence number of message
 385  * @type: message type
 386  * @payload: length of message payload
 387  * @flags: message flags
 388  *
 389  * The caller is responsible to ensure that the skb provides enough
 390  * tailroom for both the netlink header and payload.
 391  */
 392 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 393                                            u32 seq, int type, int payload,
 394                                            int flags)
 395 {
 396         struct nlmsghdr *nlh;
 397
 398         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 399         nlh->nlmsg_type = type;
 400         nlh->nlmsg_len = nlmsg_msg_size(payload);
 401         nlh->nlmsg_flags = flags;
 402         nlh->nlmsg_pid = pid;
 403         nlh->nlmsg_seq = seq;
 404
 405         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 406                nlmsg_padlen(payload));
 407
 408         return nlh;
 409 }
 410 #endif
 411
 412 /**
 413  * nlmsg_put - Add a new netlink message to an skb
 414  * @skb: socket buffer to store message in
 415  * @pid: netlink process id
 416  * @seq: sequence number of message
 417  * @type: message type
 418  * @payload: length of message payload
 419  * @flags: message flags
 420  *
 421  * Returns NULL if the tailroom of the skb is insufficient to store
 422  * the message header and payload.
 423  */
 424 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 425                                          int type, int payload, int flags)
 426 {
 427         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 428                 return NULL;
 429
 430         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 431 }
 432
 433 /**
 434  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 435  * @skb: socket buffer to store message in
 436  * @cb: netlink callback
 437  * @type: message type
 438  * @payload: length of message payload
 439  * @flags: message flags
 440  *
 441  * Returns NULL if the tailroom of the skb is insufficient to store
 442  * the message header and payload.
 443  */
 444 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 445                                                 struct netlink_callback *cb,
 446                                                 int type, int payload,
 447                                                 int flags)
 448 {
 449         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 450                          type, payload, flags);
 451 }
 452
 453 /**
 454  * nlmsg_new - Allocate a new netlink message
 455  * @size: maximum size of message
 456  *
 457  * Use NLMSG_GOODSIZE if size isn't know and you need a good default size.
 458  */
 459 static inline struct sk_buff *nlmsg_new(int size)
 460 {
 461         return alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 462 }
 463
 464 /**
 465  * nlmsg_end - Finalize a netlink message
 466  * @skb: socket buffer the message is stored in
 467  * @nlh: netlink message header
 468  *
 469  * Corrects the netlink message header to include the appeneded
 470  * attributes. Only necessary if attributes have been added to
 471  * the message.
 472  *
 473  * Returns the total data length of the skb.
 474  */
 475 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 476 {
 477         nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
 478
 479         return skb->len;
 480 }
 481
 482 /**
 483  * nlmsg_cancel - Cancel construction of a netlink message
 484  * @skb: socket buffer the message is stored in
 485  * @nlh: netlink message header
 486  *
 487  * Removes the complete netlink message including all
 488  * attributes from the socket buffer again. Returns -1.
 489  */
 490 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 491 {
 492         skb_trim(skb, (unsigned char *) nlh - skb->data);
 493
 494         return -1;
 495 }
 496
 497 /**
 498  * nlmsg_free - free a netlink message
 499  * @skb: socket buffer of netlink message
 500  */
 501 static inline void nlmsg_free(struct sk_buff *skb)
 502 {
 503         kfree_skb(skb);
 504 }
 505
 506 /**
 507  * nlmsg_multicast - multicast a netlink message
 508  * @sk: netlink socket to spread messages to
 509  * @skb: netlink message as socket buffer
 510  * @pid: own netlink pid to avoid sending to yourself
 511  * @group: multicast group id
 512  */
 513 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 514                                   u32 pid, unsigned int group)
 515 {
 516         int err;
 517
 518         NETLINK_CB(skb).dst_group = group;
 519
 520         err = netlink_broadcast(sk, skb, pid, group, GFP_KERNEL);
 521         if (err > 0)
 522                 err = 0;
 523
 524         return err;
 525 }
 526
 527 /**
 528  * nlmsg_unicast - unicast a netlink message
 529  * @sk: netlink socket to spread message to
 530  * @skb: netlink message as socket buffer
 531  * @pid: netlink pid of the destination socket
 532  */
 533 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 534 {
 535         int err;
 536
 537         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 538         if (err > 0)
 539                 err = 0;
 540
 541         return err;
 542 }
 543
 544 /**
 545  * nlmsg_for_each_msg - iterate over a stream of messages
 546  * @pos: loop counter, set to current message
 547  * @head: head of message stream
 548  * @len: length of message stream
 549  * @rem: initialized to len, holds bytes currently remaining in stream
 550  */
 551 #define nlmsg_for_each_msg(pos, head, len, rem) \
 552         for (pos = head, rem = len; \
 553              nlmsg_ok(pos, rem); \
 554              pos = nlmsg_next(pos, &(rem)))
 555
 556 /**************************************************************************
 557  * Netlink Attributes
 558  **************************************************************************/
 559
 560 /**
 561  * nla_attr_size - length of attribute not including padding
 562  * @payload: length of payload
 563  */
 564 static inline int nla_attr_size(int payload)
 565 {
 566         return NLA_HDRLEN + payload;
 567 }
 568
 569 /**
 570  * nla_total_size - total length of attribute including padding
 571  * @payload: length of payload
 572  */
 573 static inline int nla_total_size(int payload)
 574 {
 575         return NLA_ALIGN(nla_attr_size(payload));
 576 }
 577
 578 /**
 579  * nla_padlen - length of padding at the tail of attribute
 580  * @payload: length of payload
 581  */
 582 static inline int nla_padlen(int payload)
 583 {
 584         return nla_total_size(payload) - nla_attr_size(payload);
 585 }
 586
 587 /**
 588  * nla_data - head of payload
 589  * @nla: netlink attribute
 590  */
 591 static inline void *nla_data(const struct nlattr *nla)
 592 {
 593         return (char *) nla + NLA_HDRLEN;
 594 }
 595
 596 /**
 597  * nla_len - length of payload
 598  * @nla: netlink attribute
 599  */
 600 static inline int nla_len(const struct nlattr *nla)
 601 {
 602         return nla->nla_len - NLA_HDRLEN;
 603 }
 604
 605 /**
 606  * nla_ok - check if the netlink attribute fits into the remaining bytes
 607  * @nla: netlink attribute
 608  * @remaining: number of bytes remaining in attribute stream
 609  */
 610 static inline int nla_ok(const struct nlattr *nla, int remaining)
 611 {
 612         return remaining >= sizeof(*nla) &&
 613                nla->nla_len >= sizeof(*nla) &&
 614                nla->nla_len <= remaining;
 615 }
 616
 617 /**
 618  * nla_next - next netlink attribte in attribute stream
 619  * @nla: netlink attribute
 620  * @remaining: number of bytes remaining in attribute stream
 621  *
 622  * Returns the next netlink attribute in the attribute stream and
 623  * decrements remaining by the size of the current attribute.
 624  */
 625 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 626 {
 627         int totlen = NLA_ALIGN(nla->nla_len);
 628
 629         *remaining -= totlen;
 630         return (struct nlattr *) ((char *) nla + totlen);
 631 }
 632
 633 /**
 634  * nla_parse_nested - parse nested attributes
 635  * @tb: destination array with maxtype+1 elements
 636  * @maxtype: maximum attribute type to be expected
 637  * @nla: attribute containing the nested attributes
 638  * @policy: validation policy
 639  *
 640  * See nla_parse()
 641  */
 642 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 643                                    struct nlattr *nla,
 644                                    struct nla_policy *policy)
 645 {
 646         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 647 }
 648 /**
 649  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 650  * @skb: socket buffer to add attribute to
 651  * @attrtype: attribute type
 652  * @value: numeric value
 653  */
 654 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 655 {
 656         return nla_put(skb, attrtype, sizeof(u8), &value);
 657 }
 658
 659 /**
 660  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 661  * @skb: socket buffer to add attribute to
 662  * @attrtype: attribute type
 663  * @value: numeric value
 664  */
 665 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 666 {
 667         return nla_put(skb, attrtype, sizeof(u16), &value);
 668 }
 669
 670 /**
 671  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 672  * @skb: socket buffer to add attribute to
 673  * @attrtype: attribute type
 674  * @value: numeric value
 675  */
 676 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 677 {
 678         return nla_put(skb, attrtype, sizeof(u32), &value);
 679 }
 680
 681 /**
 682  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 683  * @skb: socket buffer to add attribute to
 684  * @attrtype: attribute type
 685  * @value: numeric value
 686  */
 687 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 688 {
 689         return nla_put(skb, attrtype, sizeof(u64), &value);
 690 }
 691
 692 /**
 693  * nla_put_string - Add a string netlink attribute to a socket buffer
 694  * @skb: socket buffer to add attribute to
 695  * @attrtype: attribute type
 696  * @str: NUL terminated string
 697  */
 698 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 699                                  const char *str)
 700 {
 701         return nla_put(skb, attrtype, strlen(str) + 1, str);
 702 }
 703
 704 /**
 705  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 706  * @skb: socket buffer to add attribute to
 707  * @attrtype: attribute type
 708  */
 709 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 710 {
 711         return nla_put(skb, attrtype, 0, NULL);
 712 }
 713
 714 /**
 715  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 716  * @skb: socket buffer to add attribute to
 717  * @attrtype: attribute type
 718  * @jiffies: number of msecs in jiffies
 719  */
 720 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 721                                 unsigned long jiffies)
 722 {
 723         u64 tmp = jiffies_to_msecs(jiffies);
 724         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 725 }
 726
 727 #define NLA_PUT(skb, attrtype, attrlen, data) \
 728         do { \
 729                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 730                         goto nla_put_failure; \
 731         } while(0)
 732
 733 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 734         do { \
 735                 type __tmp = value; \
 736                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 737         } while(0)
 738
 739 #define NLA_PUT_U8(skb, attrtype, value) \
 740         NLA_PUT_TYPE(skb, u8, attrtype, value)
 741
 742 #define NLA_PUT_U16(skb, attrtype, value) \
 743         NLA_PUT_TYPE(skb, u16, attrtype, value)
 744
 745 #define NLA_PUT_U32(skb, attrtype, value) \
 746         NLA_PUT_TYPE(skb, u32, attrtype, value)
 747
 748 #define NLA_PUT_U64(skb, attrtype, value) \
 749         NLA_PUT_TYPE(skb, u64, attrtype, value)
 750
 751 #define NLA_PUT_STRING(skb, attrtype, value) \
 752         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 753
 754 #define NLA_PUT_FLAG(skb, attrtype, value) \
 755         NLA_PUT(skb, attrtype, 0, NULL)
 756
 757 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 758         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 759
 760 /**
 761  * nla_get_u32 - return payload of u32 attribute
 762  * @nla: u32 netlink attribute
 763  */
 764 static inline u32 nla_get_u32(struct nlattr *nla)
 765 {
 766         return *(u32 *) nla_data(nla);
 767 }
 768
 769 /**
 770  * nla_get_u16 - return payload of u16 attribute
 771  * @nla: u16 netlink attribute
 772  */
 773 static inline u16 nla_get_u16(struct nlattr *nla)
 774 {
 775         return *(u16 *) nla_data(nla);
 776 }
 777
 778 /**
 779  * nla_get_u8 - return payload of u8 attribute
 780  * @nla: u8 netlink attribute
 781  */
 782 static inline u8 nla_get_u8(struct nlattr *nla)
 783 {
 784         return *(u8 *) nla_data(nla);
 785 }
 786
 787 /**
 788  * nla_get_u64 - return payload of u64 attribute
 789  * @nla: u64 netlink attribute
 790  */
 791 static inline u64 nla_get_u64(struct nlattr *nla)
 792 {
 793         u64 tmp;
 794
 795         nla_memcpy(&tmp, nla, sizeof(tmp));
 796
 797         return tmp;
 798 }
 799
 800 /**
 801  * nla_get_flag - return payload of flag attribute
 802  * @nla: flag netlink attribute
 803  */
 804 static inline int nla_get_flag(struct nlattr *nla)
 805 {
 806         return !!nla;
 807 }
 808
 809 /**
 810  * nla_get_msecs - return payload of msecs attribute
 811  * @nla: msecs netlink attribute
 812  *
 813  * Returns the number of milliseconds in jiffies.
 814  */
 815 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 816 {
 817         u64 msecs = nla_get_u64(nla);
 818
 819         return msecs_to_jiffies((unsigned long) msecs);
 820 }
 821
 822 /**
 823  * nla_nest_start - Start a new level of nested attributes
 824  * @skb: socket buffer to add attributes to
 825  * @attrtype: attribute type of container
 826  *
 827  * Returns the container attribute
 828  */
 829 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 830 {
 831         struct nlattr *start = (struct nlattr *) skb->tail;
 832
 833         if (nla_put(skb, attrtype, 0, NULL) < 0)
 834                 return NULL;
 835
 836         return start;
 837 }
 838
 839 /**
 840  * nla_nest_end - Finalize nesting of attributes
 841  * @skb: socket buffer the attribtues are stored in
 842  * @start: container attribute
 843  *
 844  * Corrects the container attribute header to include the all
 845  * appeneded attributes.
 846  *
 847  * Returns the total data length of the skb.
 848  */
 849 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 850 {
 851         start->nla_len = skb->tail - (unsigned char *) start;
 852         return skb->len;
 853 }
 854
 855 /**
 856  * nla_nest_cancel - Cancel nesting of attributes
 857  * @skb: socket buffer the message is stored in
 858  * @start: container attribute
 859  *
 860  * Removes the container attribute and including all nested
 861  * attributes. Returns -1.
 862  */
 863 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 864 {
 865         if (start)
 866                 skb_trim(skb, (unsigned char *) start - skb->data);
 867
 868         return -1;
 869 }
 870
 871 /**
 872  * nla_for_each_attr - iterate over a stream of attributes
 873  * @pos: loop counter, set to current attribute
 874  * @head: head of attribute stream
 875  * @len: length of attribute stream
 876  * @rem: initialized to len, holds bytes currently remaining in stream
 877  */
 878 #define nla_for_each_attr(pos, head, len, rem) \
 879         for (pos = head, rem = len; \
 880              nla_ok(pos, rem); \
 881              pos = nla_next(pos, &(rem)))
 882
 883 #endif