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_find()                         find attribute in stream of attributes
 150  *   nla_find_nested()                  find attribute in nested attributes
 151  *   nla_parse()                        parse and validate stream of attrs
 152  *   nla_parse_nested()                 parse nested attribuets
 153  *   nla_for_each_attr()                loop over all attributes
 154  *=========================================================================
 155  */
 156
 157  /**
 158   * Standard attribute types to specify validation policy
 159   */
 160 enum {
 161         NLA_UNSPEC,
 162         NLA_U8,
 163         NLA_U16,
 164         NLA_U32,
 165         NLA_U64,
 166         NLA_STRING,
 167         NLA_FLAG,
 168         NLA_MSECS,
 169         NLA_NESTED,
 170         NLA_NUL_STRING,
 171         __NLA_TYPE_MAX,
 172 };
 173
 174 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 175
 176 /**
 177  * struct nla_policy - attribute validation policy
 178  * @type: Type of attribute or NLA_UNSPEC
 179  * @len: Type specific length of payload
 180  *
 181  * Policies are defined as arrays of this struct, the array must be
 182  * accessible by attribute type up to the highest identifier to be expected.
 183  *
 184  * Meaning of `len' field:
 185  *    NLA_STRING           Maximum length of string
 186  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 187  *    NLA_FLAG             Unused
 188  *    All other            Exact length of attribute payload
 189  *
 190  * Example:
 191  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 192  *      [ATTR_FOO] = { .type = NLA_U16 },
 193  *      [ATTR_BAR] = { .type = NLA_STRING, len = BARSIZ },
 194  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 195  * };
 196  */
 197 struct nla_policy {
 198         u16             type;
 199         u16             len;
 200 };
 201
 202 /**
 203  * struct nl_info - netlink source information
 204  * @nlh: Netlink message header of original request
 205  * @pid: Netlink PID of requesting application
 206  */
 207 struct nl_info {
 208         struct nlmsghdr         *nlh;
 209         u32                     pid;
 210 };
 211
 212 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 213                                           int (*cb)(struct sk_buff *,
 214                                                     struct nlmsghdr *, int *));
 215 extern void             netlink_queue_skip(struct nlmsghdr *nlh,
 216                                            struct sk_buff *skb);
 217 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 218                                      u32 pid, unsigned int group, int report,
 219                                      gfp_t flags);
 220
 221 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 222                                      struct nla_policy *policy);
 223 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 224                                   struct nlattr *head, int len,
 225                                   struct nla_policy *policy);
 226 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 227 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 228                                     size_t dstsize);
 229 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 230 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 231                                    size_t size);
 232 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 233 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 234                                       int attrlen);
 235 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 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 void             __nla_put(struct sk_buff *skb, int attrtype,
 240                                   int attrlen, const void *data);
 241 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 242                                         const void *data);
 243 extern int              nla_put(struct sk_buff *skb, int attrtype,
 244                                 int attrlen, const void *data);
 245 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 246                                       const void *data);
 247
 248 /**************************************************************************
 249  * Netlink Messages
 250  **************************************************************************/
 251
 252 /**
 253  * nlmsg_msg_size - length of netlink message not including padding
 254  * @payload: length of message payload
 255  */
 256 static inline int nlmsg_msg_size(int payload)
 257 {
 258         return NLMSG_HDRLEN + payload;
 259 }
 260
 261 /**
 262  * nlmsg_total_size - length of netlink message including padding
 263  * @payload: length of message payload
 264  */
 265 static inline int nlmsg_total_size(int payload)
 266 {
 267         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 268 }
 269
 270 /**
 271  * nlmsg_padlen - length of padding at the message's tail
 272  * @payload: length of message payload
 273  */
 274 static inline int nlmsg_padlen(int payload)
 275 {
 276         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 277 }
 278
 279 /**
 280  * nlmsg_data - head of message payload
 281  * @nlh: netlink messsage header
 282  */
 283 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 284 {
 285         return (unsigned char *) nlh + NLMSG_HDRLEN;
 286 }
 287
 288 /**
 289  * nlmsg_len - length of message payload
 290  * @nlh: netlink message header
 291  */
 292 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 293 {
 294         return nlh->nlmsg_len - NLMSG_HDRLEN;
 295 }
 296
 297 /**
 298  * nlmsg_attrdata - head of attributes data
 299  * @nlh: netlink message header
 300  * @hdrlen: length of family specific header
 301  */
 302 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 303                                             int hdrlen)
 304 {
 305         unsigned char *data = nlmsg_data(nlh);
 306         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 307 }
 308
 309 /**
 310  * nlmsg_attrlen - length of attributes data
 311  * @nlh: netlink message header
 312  * @hdrlen: length of family specific header
 313  */
 314 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 315 {
 316         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 317 }
 318
 319 /**
 320  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 321  * @nlh: netlink message header
 322  * @remaining: number of bytes remaining in message stream
 323  */
 324 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 325 {
 326         return (remaining >= sizeof(struct nlmsghdr) &&
 327                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 328                 nlh->nlmsg_len <= remaining);
 329 }
 330
 331 /**
 332  * nlmsg_next - next netlink message in message stream
 333  * @nlh: netlink message header
 334  * @remaining: number of bytes remaining in message stream
 335  *
 336  * Returns the next netlink message in the message stream and
 337  * decrements remaining by the size of the current message.
 338  */
 339 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 340 {
 341         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 342
 343         *remaining -= totlen;
 344
 345         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 346 }
 347
 348 /**
 349  * nlmsg_parse - parse attributes of a netlink message
 350  * @nlh: netlink message header
 351  * @hdrlen: length of family specific header
 352  * @tb: destination array with maxtype+1 elements
 353  * @maxtype: maximum attribute type to be expected
 354  * @policy: validation policy
 355  *
 356  * See nla_parse()
 357  */
 358 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 359                               struct nlattr *tb[], int maxtype,
 360                               struct nla_policy *policy)
 361 {
 362         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 363                 return -EINVAL;
 364
 365         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 366                          nlmsg_attrlen(nlh, hdrlen), policy);
 367 }
 368
 369 /**
 370  * nlmsg_find_attr - find a specific attribute in a netlink message
 371  * @nlh: netlink message header
 372  * @hdrlen: length of familiy specific header
 373  * @attrtype: type of attribute to look for
 374  *
 375  * Returns the first attribute which matches the specified type.
 376  */
 377 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 378                                              int hdrlen, int attrtype)
 379 {
 380         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 381                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 382 }
 383
 384 /**
 385  * nlmsg_validate - validate a netlink message including attributes
 386  * @nlh: netlinket message header
 387  * @hdrlen: length of familiy specific header
 388  * @maxtype: maximum attribute type to be expected
 389  * @policy: validation policy
 390  */
 391 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 392                                  struct nla_policy *policy)
 393 {
 394         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 395                 return -EINVAL;
 396
 397         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 398                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 399 }
 400
 401 /**
 402  * nlmsg_report - need to report back to application?
 403  * @nlh: netlink message header
 404  *
 405  * Returns 1 if a report back to the application is requested.
 406  */
 407 static inline int nlmsg_report(struct nlmsghdr *nlh)
 408 {
 409         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 410 }
 411
 412 /**
 413  * nlmsg_for_each_attr - iterate over a stream of attributes
 414  * @pos: loop counter, set to current attribute
 415  * @nlh: netlink message header
 416  * @hdrlen: length of familiy specific header
 417  * @rem: initialized to len, holds bytes currently remaining in stream
 418  */
 419 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 420         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 421                           nlmsg_attrlen(nlh, hdrlen), rem)
 422
 423 #if 0
 424 /* FIXME: Enable once all users have been converted */
 425
 426 /**
 427  * __nlmsg_put - Add a new netlink message to an skb
 428  * @skb: socket buffer to store message in
 429  * @pid: netlink process id
 430  * @seq: sequence number of message
 431  * @type: message type
 432  * @payload: length of message payload
 433  * @flags: message flags
 434  *
 435  * The caller is responsible to ensure that the skb provides enough
 436  * tailroom for both the netlink header and payload.
 437  */
 438 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 439                                            u32 seq, int type, int payload,
 440                                            int flags)
 441 {
 442         struct nlmsghdr *nlh;
 443
 444         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 445         nlh->nlmsg_type = type;
 446         nlh->nlmsg_len = nlmsg_msg_size(payload);
 447         nlh->nlmsg_flags = flags;
 448         nlh->nlmsg_pid = pid;
 449         nlh->nlmsg_seq = seq;
 450
 451         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 452                nlmsg_padlen(payload));
 453
 454         return nlh;
 455 }
 456 #endif
 457
 458 /**
 459  * nlmsg_put - Add a new netlink message to an skb
 460  * @skb: socket buffer to store message in
 461  * @pid: netlink process id
 462  * @seq: sequence number of message
 463  * @type: message type
 464  * @payload: length of message payload
 465  * @flags: message flags
 466  *
 467  * Returns NULL if the tailroom of the skb is insufficient to store
 468  * the message header and payload.
 469  */
 470 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 471                                          int type, int payload, int flags)
 472 {
 473         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 474                 return NULL;
 475
 476         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 477 }
 478
 479 /**
 480  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 481  * @skb: socket buffer to store message in
 482  * @cb: netlink callback
 483  * @type: message type
 484  * @payload: length of message payload
 485  * @flags: message flags
 486  *
 487  * Returns NULL if the tailroom of the skb is insufficient to store
 488  * the message header and payload.
 489  */
 490 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 491                                                 struct netlink_callback *cb,
 492                                                 int type, int payload,
 493                                                 int flags)
 494 {
 495         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 496                          type, payload, flags);
 497 }
 498
 499 /**
 500  * nlmsg_new - Allocate a new netlink message
 501  * @size: maximum size of message
 502  * @flags: the type of memory to allocate.
 503  *
 504  * Use NLMSG_GOODSIZE if size isn't know and you need a good default size.
 505  */
 506 static inline struct sk_buff *nlmsg_new(int size, gfp_t flags)
 507 {
 508         return alloc_skb(size, flags);
 509 }
 510
 511 /**
 512  * nlmsg_end - Finalize a netlink message
 513  * @skb: socket buffer the message is stored in
 514  * @nlh: netlink message header
 515  *
 516  * Corrects the netlink message header to include the appeneded
 517  * attributes. Only necessary if attributes have been added to
 518  * the message.
 519  *
 520  * Returns the total data length of the skb.
 521  */
 522 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 523 {
 524         nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
 525
 526         return skb->len;
 527 }
 528
 529 /**
 530  * nlmsg_get_pos - return current position in netlink message
 531  * @skb: socket buffer the message is stored in
 532  *
 533  * Returns a pointer to the current tail of the message.
 534  */
 535 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 536 {
 537         return skb->tail;
 538 }
 539
 540 /**
 541  * nlmsg_trim - Trim message to a mark
 542  * @skb: socket buffer the message is stored in
 543  * @mark: mark to trim to
 544  *
 545  * Trims the message to the provided mark. Returns -1.
 546  */
 547 static inline int nlmsg_trim(struct sk_buff *skb, void *mark)
 548 {
 549         if (mark)
 550                 skb_trim(skb, (unsigned char *) mark - skb->data);
 551
 552         return -1;
 553 }
 554
 555 /**
 556  * nlmsg_cancel - Cancel construction of a netlink message
 557  * @skb: socket buffer the message is stored in
 558  * @nlh: netlink message header
 559  *
 560  * Removes the complete netlink message including all
 561  * attributes from the socket buffer again. Returns -1.
 562  */
 563 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 564 {
 565         return nlmsg_trim(skb, nlh);
 566 }
 567
 568 /**
 569  * nlmsg_free - free a netlink message
 570  * @skb: socket buffer of netlink message
 571  */
 572 static inline void nlmsg_free(struct sk_buff *skb)
 573 {
 574         kfree_skb(skb);
 575 }
 576
 577 /**
 578  * nlmsg_multicast - multicast a netlink message
 579  * @sk: netlink socket to spread messages to
 580  * @skb: netlink message as socket buffer
 581  * @pid: own netlink pid to avoid sending to yourself
 582  * @group: multicast group id
 583  * @flags: allocation flags
 584  */
 585 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 586                                   u32 pid, unsigned int group, gfp_t flags)
 587 {
 588         int err;
 589
 590         NETLINK_CB(skb).dst_group = group;
 591
 592         err = netlink_broadcast(sk, skb, pid, group, flags);
 593         if (err > 0)
 594                 err = 0;
 595
 596         return err;
 597 }
 598
 599 /**
 600  * nlmsg_unicast - unicast a netlink message
 601  * @sk: netlink socket to spread message to
 602  * @skb: netlink message as socket buffer
 603  * @pid: netlink pid of the destination socket
 604  */
 605 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 606 {
 607         int err;
 608
 609         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 610         if (err > 0)
 611                 err = 0;
 612
 613         return err;
 614 }
 615
 616 /**
 617  * nlmsg_for_each_msg - iterate over a stream of messages
 618  * @pos: loop counter, set to current message
 619  * @head: head of message stream
 620  * @len: length of message stream
 621  * @rem: initialized to len, holds bytes currently remaining in stream
 622  */
 623 #define nlmsg_for_each_msg(pos, head, len, rem) \
 624         for (pos = head, rem = len; \
 625              nlmsg_ok(pos, rem); \
 626              pos = nlmsg_next(pos, &(rem)))
 627
 628 /**************************************************************************
 629  * Netlink Attributes
 630  **************************************************************************/
 631
 632 /**
 633  * nla_attr_size - length of attribute not including padding
 634  * @payload: length of payload
 635  */
 636 static inline int nla_attr_size(int payload)
 637 {
 638         return NLA_HDRLEN + payload;
 639 }
 640
 641 /**
 642  * nla_total_size - total length of attribute including padding
 643  * @payload: length of payload
 644  */
 645 static inline int nla_total_size(int payload)
 646 {
 647         return NLA_ALIGN(nla_attr_size(payload));
 648 }
 649
 650 /**
 651  * nla_padlen - length of padding at the tail of attribute
 652  * @payload: length of payload
 653  */
 654 static inline int nla_padlen(int payload)
 655 {
 656         return nla_total_size(payload) - nla_attr_size(payload);
 657 }
 658
 659 /**
 660  * nla_data - head of payload
 661  * @nla: netlink attribute
 662  */
 663 static inline void *nla_data(const struct nlattr *nla)
 664 {
 665         return (char *) nla + NLA_HDRLEN;
 666 }
 667
 668 /**
 669  * nla_len - length of payload
 670  * @nla: netlink attribute
 671  */
 672 static inline int nla_len(const struct nlattr *nla)
 673 {
 674         return nla->nla_len - NLA_HDRLEN;
 675 }
 676
 677 /**
 678  * nla_ok - check if the netlink attribute fits into the remaining bytes
 679  * @nla: netlink attribute
 680  * @remaining: number of bytes remaining in attribute stream
 681  */
 682 static inline int nla_ok(const struct nlattr *nla, int remaining)
 683 {
 684         return remaining >= sizeof(*nla) &&
 685                nla->nla_len >= sizeof(*nla) &&
 686                nla->nla_len <= remaining;
 687 }
 688
 689 /**
 690  * nla_next - next netlink attribte in attribute stream
 691  * @nla: netlink attribute
 692  * @remaining: number of bytes remaining in attribute stream
 693  *
 694  * Returns the next netlink attribute in the attribute stream and
 695  * decrements remaining by the size of the current attribute.
 696  */
 697 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 698 {
 699         int totlen = NLA_ALIGN(nla->nla_len);
 700
 701         *remaining -= totlen;
 702         return (struct nlattr *) ((char *) nla + totlen);
 703 }
 704
 705 /**
 706  * nla_find_nested - find attribute in a set of nested attributes
 707  * @nla: attribute containing the nested attributes
 708  * @attrtype: type of attribute to look for
 709  *
 710  * Returns the first attribute which matches the specified type.
 711  */
 712 static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
 713 {
 714         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 715 }
 716
 717 /**
 718  * nla_parse_nested - parse nested attributes
 719  * @tb: destination array with maxtype+1 elements
 720  * @maxtype: maximum attribute type to be expected
 721  * @nla: attribute containing the nested attributes
 722  * @policy: validation policy
 723  *
 724  * See nla_parse()
 725  */
 726 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 727                                    struct nlattr *nla,
 728                                    struct nla_policy *policy)
 729 {
 730         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 731 }
 732 /**
 733  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 734  * @skb: socket buffer to add attribute to
 735  * @attrtype: attribute type
 736  * @value: numeric value
 737  */
 738 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 739 {
 740         return nla_put(skb, attrtype, sizeof(u8), &value);
 741 }
 742
 743 /**
 744  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 745  * @skb: socket buffer to add attribute to
 746  * @attrtype: attribute type
 747  * @value: numeric value
 748  */
 749 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 750 {
 751         return nla_put(skb, attrtype, sizeof(u16), &value);
 752 }
 753
 754 /**
 755  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 756  * @skb: socket buffer to add attribute to
 757  * @attrtype: attribute type
 758  * @value: numeric value
 759  */
 760 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 761 {
 762         return nla_put(skb, attrtype, sizeof(u32), &value);
 763 }
 764
 765 /**
 766  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 767  * @skb: socket buffer to add attribute to
 768  * @attrtype: attribute type
 769  * @value: numeric value
 770  */
 771 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 772 {
 773         return nla_put(skb, attrtype, sizeof(u64), &value);
 774 }
 775
 776 /**
 777  * nla_put_string - Add a string netlink attribute to a socket buffer
 778  * @skb: socket buffer to add attribute to
 779  * @attrtype: attribute type
 780  * @str: NUL terminated string
 781  */
 782 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 783                                  const char *str)
 784 {
 785         return nla_put(skb, attrtype, strlen(str) + 1, str);
 786 }
 787
 788 /**
 789  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 790  * @skb: socket buffer to add attribute to
 791  * @attrtype: attribute type
 792  */
 793 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 794 {
 795         return nla_put(skb, attrtype, 0, NULL);
 796 }
 797
 798 /**
 799  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 800  * @skb: socket buffer to add attribute to
 801  * @attrtype: attribute type
 802  * @jiffies: number of msecs in jiffies
 803  */
 804 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 805                                 unsigned long jiffies)
 806 {
 807         u64 tmp = jiffies_to_msecs(jiffies);
 808         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 809 }
 810
 811 #define NLA_PUT(skb, attrtype, attrlen, data) \
 812         do { \
 813                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 814                         goto nla_put_failure; \
 815         } while(0)
 816
 817 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 818         do { \
 819                 type __tmp = value; \
 820                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 821         } while(0)
 822
 823 #define NLA_PUT_U8(skb, attrtype, value) \
 824         NLA_PUT_TYPE(skb, u8, attrtype, value)
 825
 826 #define NLA_PUT_U16(skb, attrtype, value) \
 827         NLA_PUT_TYPE(skb, u16, attrtype, value)
 828
 829 #define NLA_PUT_U32(skb, attrtype, value) \
 830         NLA_PUT_TYPE(skb, u32, attrtype, value)
 831
 832 #define NLA_PUT_U64(skb, attrtype, value) \
 833         NLA_PUT_TYPE(skb, u64, attrtype, value)
 834
 835 #define NLA_PUT_STRING(skb, attrtype, value) \
 836         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 837
 838 #define NLA_PUT_FLAG(skb, attrtype) \
 839         NLA_PUT(skb, attrtype, 0, NULL)
 840
 841 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 842         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 843
 844 /**
 845  * nla_get_u32 - return payload of u32 attribute
 846  * @nla: u32 netlink attribute
 847  */
 848 static inline u32 nla_get_u32(struct nlattr *nla)
 849 {
 850         return *(u32 *) nla_data(nla);
 851 }
 852
 853 /**
 854  * nla_get_u16 - return payload of u16 attribute
 855  * @nla: u16 netlink attribute
 856  */
 857 static inline u16 nla_get_u16(struct nlattr *nla)
 858 {
 859         return *(u16 *) nla_data(nla);
 860 }
 861
 862 /**
 863  * nla_get_u8 - return payload of u8 attribute
 864  * @nla: u8 netlink attribute
 865  */
 866 static inline u8 nla_get_u8(struct nlattr *nla)
 867 {
 868         return *(u8 *) nla_data(nla);
 869 }
 870
 871 /**
 872  * nla_get_u64 - return payload of u64 attribute
 873  * @nla: u64 netlink attribute
 874  */
 875 static inline u64 nla_get_u64(struct nlattr *nla)
 876 {
 877         u64 tmp;
 878
 879         nla_memcpy(&tmp, nla, sizeof(tmp));
 880
 881         return tmp;
 882 }
 883
 884 /**
 885  * nla_get_flag - return payload of flag attribute
 886  * @nla: flag netlink attribute
 887  */
 888 static inline int nla_get_flag(struct nlattr *nla)
 889 {
 890         return !!nla;
 891 }
 892
 893 /**
 894  * nla_get_msecs - return payload of msecs attribute
 895  * @nla: msecs netlink attribute
 896  *
 897  * Returns the number of milliseconds in jiffies.
 898  */
 899 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 900 {
 901         u64 msecs = nla_get_u64(nla);
 902
 903         return msecs_to_jiffies((unsigned long) msecs);
 904 }
 905
 906 /**
 907  * nla_nest_start - Start a new level of nested attributes
 908  * @skb: socket buffer to add attributes to
 909  * @attrtype: attribute type of container
 910  *
 911  * Returns the container attribute
 912  */
 913 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 914 {
 915         struct nlattr *start = (struct nlattr *) skb->tail;
 916
 917         if (nla_put(skb, attrtype, 0, NULL) < 0)
 918                 return NULL;
 919
 920         return start;
 921 }
 922
 923 /**
 924  * nla_nest_end - Finalize nesting of attributes
 925  * @skb: socket buffer the attribtues are stored in
 926  * @start: container attribute
 927  *
 928  * Corrects the container attribute header to include the all
 929  * appeneded attributes.
 930  *
 931  * Returns the total data length of the skb.
 932  */
 933 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
 934 {
 935         start->nla_len = skb->tail - (unsigned char *) start;
 936         return skb->len;
 937 }
 938
 939 /**
 940  * nla_nest_cancel - Cancel nesting of attributes
 941  * @skb: socket buffer the message is stored in
 942  * @start: container attribute
 943  *
 944  * Removes the container attribute and including all nested
 945  * attributes. Returns -1.
 946  */
 947 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
 948 {
 949         return nlmsg_trim(skb, start);
 950 }
 951
 952 /**
 953  * nla_for_each_attr - iterate over a stream of attributes
 954  * @pos: loop counter, set to current attribute
 955  * @head: head of attribute stream
 956  * @len: length of attribute stream
 957  * @rem: initialized to len, holds bytes currently remaining in stream
 958  */
 959 #define nla_for_each_attr(pos, head, len, rem) \
 960         for (pos = head, rem = len; \
 961              nla_ok(pos, rem); \
 962              pos = nla_next(pos, &(rem)))
 963
 964 /**
 965  * nla_for_each_nested - iterate over nested attributes
 966  * @pos: loop counter, set to current attribute
 967  * @nla: attribute containing the nested attributes
 968  * @rem: initialized to len, holds bytes currently remaining in stream
 969  */
 970 #define nla_for_each_nested(pos, nla, rem) \
 971         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
 972
 973 #endif