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