include/net/netlink.h

   1 #ifndef __NET_NETLINK_H
   2 #define __NET_NETLINK_H
   3
   4 #include <linux/types.h>
   5 #include <linux/netlink.h>
   6 #include <linux/jiffies.h>
   7
   8 /* ========================================================================
   9  *         Netlink Messages and Attributes Interface (As Seen On TV)
  10  * ------------------------------------------------------------------------
  11  *                          Messages Interface
  12  * ------------------------------------------------------------------------
  13  *
  14  * Message Format:
  15  *    <--- nlmsg_total_size(payload)  --->
  16  *    <-- nlmsg_msg_size(payload) ->
  17  *   +----------+- - -+-------------+- - -+-------- - -
  18  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  19  *   +----------+- - -+-------------+- - -+-------- - -
  20  *   nlmsg_data(nlh)---^                   ^
  21  *   nlmsg_next(nlh)-----------------------+
  22  *
  23  * Payload Format:
  24  *    <---------------------- nlmsg_len(nlh) --------------------->
  25  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  26  *   +----------------------+- - -+--------------------------------+
  27  *   |     Family Header    | Pad |           Attributes           |
  28  *   +----------------------+- - -+--------------------------------+
  29  *   nlmsg_attrdata(nlh, hdrlen)---^
  30  *
  31  * Data Structures:
  32  *   struct nlmsghdr                    netlink message header
  33  *
  34  * Message Construction:
  35  *   nlmsg_new()                        create a new netlink message
  36  *   nlmsg_put()                        add a netlink message to an skb
  37  *   nlmsg_put_answer()                 callback based nlmsg_put()
  38  *   nlmsg_end()                        finanlize netlink message
  39  *   nlmsg_get_pos()                    return current position in message
  40  *   nlmsg_trim()                       trim part of message
  41  *   nlmsg_cancel()                     cancel message construction
  42  *   nlmsg_free()                       free a netlink message
  43  *
  44  * Message Sending:
  45  *   nlmsg_multicast()                  multicast message to several groups
  46  *   nlmsg_unicast()                    unicast a message to a single socket
  47  *   nlmsg_notify()                     send notification message
  48  *
  49  * Message Length Calculations:
  50  *   nlmsg_msg_size(payload)            length of message w/o padding
  51  *   nlmsg_total_size(payload)          length of message w/ padding
  52  *   nlmsg_padlen(payload)              length of padding at tail
  53  *
  54  * Message Payload Access:
  55  *   nlmsg_data(nlh)                    head of message payload
  56  *   nlmsg_len(nlh)                     length of message payload
  57  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  58  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  59  *
  60  * Message Parsing:
  61  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  62  *   nlmsg_next(nlh, remaining)         get next netlink message
  63  *   nlmsg_parse()                      parse attributes of a message
  64  *   nlmsg_find_attr()                  find an attribute in a message
  65  *   nlmsg_for_each_msg()               loop over all messages
  66  *   nlmsg_validate()                   validate netlink message incl. attrs
  67  *   nlmsg_for_each_attr()              loop over all attributes
  68  *
  69  * Misc:
  70  *   nlmsg_report()                     report back to application?
  71  *
  72  * ------------------------------------------------------------------------
  73  *                          Attributes Interface
  74  * ------------------------------------------------------------------------
  75  *
  76  * Attribute Format:
  77  *    <------- nla_total_size(payload) ------->
  78  *    <---- nla_attr_size(payload) ----->
  79  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  80  *   |  Header  | Pad |     Payload      | Pad |  Header
  81  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  82  *                     <- nla_len(nla) ->      ^
  83  *   nla_data(nla)----^                        |
  84  *   nla_next(nla)-----------------------------'
  85  *
  86  * Data Structures:
  87  *   struct nlattr                      netlink attribtue header
  88  *
  89  * Attribute Construction:
  90  *   nla_reserve(skb, type, len)        reserve room for an attribute
  91  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  92  *   nla_put(skb, type, len, data)      add attribute to skb
  93  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  94  *
  95  * Attribute Construction for Basic Types:
  96  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  97  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  98  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
  99  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
 100  *   nla_put_string(skb, type, str)     add string attribute to skb
 101  *   nla_put_flag(skb, type)            add flag attribute to skb
 102  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 103  *
 104  * Exceptions Based Attribute Construction:
 105  *   NLA_PUT(skb, type, len, data)      add attribute to skb
 106  *   NLA_PUT_U8(skb, type, value)       add u8 attribute to skb
 107  *   NLA_PUT_U16(skb, type, value)      add u16 attribute to skb
 108  *   NLA_PUT_U32(skb, type, value)      add u32 attribute to skb
 109  *   NLA_PUT_U64(skb, type, value)      add u64 attribute to skb
 110  *   NLA_PUT_STRING(skb, type, str)     add string attribute to skb
 111  *   NLA_PUT_FLAG(skb, type)            add flag attribute to skb
 112  *   NLA_PUT_MSECS(skb, type, jiffies)  add msecs attribute to skb
 113  *
 114  *   The meaning of these functions is equal to their lower case
 115  *   variants but they jump to the label nla_put_failure in case
 116  *   of a failure.
 117  *
 118  * Nested Attributes Construction:
 119  *   nla_nest_start(skb, type)          start a nested attribute
 120  *   nla_nest_end(skb, nla)             finalize a nested attribute
 121  *   nla_nest_compat_start(skb, type,   start a nested compat attribute
 122  *                         len, data)
 123  *   nla_nest_compat_end(skb, type)     finalize a nested compat attribute
 124  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 125  *
 126  * Attribute Length Calculations:
 127  *   nla_attr_size(payload)             length of attribute w/o padding
 128  *   nla_total_size(payload)            length of attribute w/ padding
 129  *   nla_padlen(payload)                length of padding
 130  *
 131  * Attribute Payload Access:
 132  *   nla_data(nla)                      head of attribute payload
 133  *   nla_len(nla)                       length of attribute payload
 134  *
 135  * Attribute Payload Access for Basic Types:
 136  *   nla_get_u8(nla)                    get payload for a u8 attribute
 137  *   nla_get_u16(nla)                   get payload for a u16 attribute
 138  *   nla_get_u32(nla)                   get payload for a u32 attribute
 139  *   nla_get_u64(nla)                   get payload for a u64 attribute
 140  *   nla_get_flag(nla)                  return 1 if flag is true
 141  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 142  *
 143  * Attribute Misc:
 144  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 145  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 146  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 147  *   nla_strcmp(nla, str)               compare attribute with string
 148  *
 149  * Attribute Parsing:
 150  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 151  *   nla_next(nla, remaining)           get next netlink attribute
 152  *   nla_validate()                     validate a stream of attributes
 153  *   nla_validate_nested()              validate a stream of nested attributes
 154  *   nla_find()                         find attribute in stream of attributes
 155  *   nla_find_nested()                  find attribute in nested attributes
 156  *   nla_parse()                        parse and validate stream of attrs
 157  *   nla_parse_nested()                 parse nested attribuets
 158  *   nla_parse_nested_compat()          parse nested compat attributes
 159  *   nla_for_each_attr()                loop over all attributes
 160  *   nla_for_each_nested()              loop over the nested attributes
 161  *=========================================================================
 162  */
 163
 164  /**
 165   * Standard attribute types to specify validation policy
 166   */
 167 enum {
 168         NLA_UNSPEC,
 169         NLA_U8,
 170         NLA_U16,
 171         NLA_U32,
 172         NLA_U64,
 173         NLA_STRING,
 174         NLA_FLAG,
 175         NLA_MSECS,
 176         NLA_NESTED,
 177         NLA_NESTED_COMPAT,
 178         NLA_NUL_STRING,
 179         NLA_BINARY,
 180         __NLA_TYPE_MAX,
 181 };
 182
 183 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 184
 185 /**
 186  * struct nla_policy - attribute validation policy
 187  * @type: Type of attribute or NLA_UNSPEC
 188  * @len: Type specific length of payload
 189  *
 190  * Policies are defined as arrays of this struct, the array must be
 191  * accessible by attribute type up to the highest identifier to be expected.
 192  *
 193  * Meaning of `len' field:
 194  *    NLA_STRING           Maximum length of string
 195  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 196  *    NLA_FLAG             Unused
 197  *    NLA_BINARY           Maximum length of attribute payload
 198  *    NLA_NESTED_COMPAT    Exact length of structure payload
 199  *    All other            Exact length of attribute payload
 200  *
 201  * Example:
 202  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 203  *      [ATTR_FOO] = { .type = NLA_U16 },
 204  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 205  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 206  * };
 207  */
 208 struct nla_policy {
 209         u16             type;
 210         u16             len;
 211 };
 212
 213 /**
 214  * struct nl_info - netlink source information
 215  * @nlh: Netlink message header of original request
 216  * @pid: Netlink PID of requesting application
 217  */
 218 struct nl_info {
 219         struct nlmsghdr         *nlh;
 220         u32                     pid;
 221 };
 222
 223 extern void             netlink_run_queue(struct sock *sk, unsigned int *qlen,
 224                                           int (*cb)(struct sk_buff *,
 225                                                     struct nlmsghdr *));
 226 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 227                                      u32 pid, unsigned int group, int report,
 228                                      gfp_t flags);
 229
 230 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 231                                      const struct nla_policy *policy);
 232 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 233                                   struct nlattr *head, int len,
 234                                   const struct nla_policy *policy);
 235 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 236 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 237                                     size_t dstsize);
 238 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 239 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 240                                    size_t size);
 241 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 242 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 243                                       int attrlen);
 244 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 245 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 246                                     int attrlen);
 247 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 248 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 249                                   int attrlen, const void *data);
 250 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 251                                         const void *data);
 252 extern int              nla_put(struct sk_buff *skb, int attrtype,
 253                                 int attrlen, const void *data);
 254 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 255                                       const void *data);
 256
 257 /**************************************************************************
 258  * Netlink Messages
 259  **************************************************************************/
 260
 261 /**
 262  * nlmsg_msg_size - length of netlink message not including padding
 263  * @payload: length of message payload
 264  */
 265 static inline int nlmsg_msg_size(int payload)
 266 {
 267         return NLMSG_HDRLEN + payload;
 268 }
 269
 270 /**
 271  * nlmsg_total_size - length of netlink message including padding
 272  * @payload: length of message payload
 273  */
 274 static inline int nlmsg_total_size(int payload)
 275 {
 276         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 277 }
 278
 279 /**
 280  * nlmsg_padlen - length of padding at the message's tail
 281  * @payload: length of message payload
 282  */
 283 static inline int nlmsg_padlen(int payload)
 284 {
 285         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 286 }
 287
 288 /**
 289  * nlmsg_data - head of message payload
 290  * @nlh: netlink messsage header
 291  */
 292 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 293 {
 294         return (unsigned char *) nlh + NLMSG_HDRLEN;
 295 }
 296
 297 /**
 298  * nlmsg_len - length of message payload
 299  * @nlh: netlink message header
 300  */
 301 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 302 {
 303         return nlh->nlmsg_len - NLMSG_HDRLEN;
 304 }
 305
 306 /**
 307  * nlmsg_attrdata - head of attributes data
 308  * @nlh: netlink message header
 309  * @hdrlen: length of family specific header
 310  */
 311 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 312                                             int hdrlen)
 313 {
 314         unsigned char *data = nlmsg_data(nlh);
 315         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 316 }
 317
 318 /**
 319  * nlmsg_attrlen - length of attributes data
 320  * @nlh: netlink message header
 321  * @hdrlen: length of family specific header
 322  */
 323 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 324 {
 325         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 326 }
 327
 328 /**
 329  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 330  * @nlh: netlink message header
 331  * @remaining: number of bytes remaining in message stream
 332  */
 333 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 334 {
 335         return (remaining >= sizeof(struct nlmsghdr) &&
 336                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 337                 nlh->nlmsg_len <= remaining);
 338 }
 339
 340 /**
 341  * nlmsg_next - next netlink message in message stream
 342  * @nlh: netlink message header
 343  * @remaining: number of bytes remaining in message stream
 344  *
 345  * Returns the next netlink message in the message stream and
 346  * decrements remaining by the size of the current message.
 347  */
 348 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 349 {
 350         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 351
 352         *remaining -= totlen;
 353
 354         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 355 }
 356
 357 /**
 358  * nlmsg_parse - parse attributes of a netlink message
 359  * @nlh: netlink message header
 360  * @hdrlen: length of family specific header
 361  * @tb: destination array with maxtype+1 elements
 362  * @maxtype: maximum attribute type to be expected
 363  * @policy: validation policy
 364  *
 365  * See nla_parse()
 366  */
 367 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 368                               struct nlattr *tb[], int maxtype,
 369                               const struct nla_policy *policy)
 370 {
 371         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 372                 return -EINVAL;
 373
 374         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 375                          nlmsg_attrlen(nlh, hdrlen), policy);
 376 }
 377
 378 /**
 379  * nlmsg_find_attr - find a specific attribute in a netlink message
 380  * @nlh: netlink message header
 381  * @hdrlen: length of familiy specific header
 382  * @attrtype: type of attribute to look for
 383  *
 384  * Returns the first attribute which matches the specified type.
 385  */
 386 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 387                                              int hdrlen, int attrtype)
 388 {
 389         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 390                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 391 }
 392
 393 /**
 394  * nlmsg_validate - validate a netlink message including attributes
 395  * @nlh: netlinket message header
 396  * @hdrlen: length of familiy specific header
 397  * @maxtype: maximum attribute type to be expected
 398  * @policy: validation policy
 399  */
 400 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 401                                  const struct nla_policy *policy)
 402 {
 403         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 404                 return -EINVAL;
 405
 406         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 407                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 408 }
 409
 410 /**
 411  * nlmsg_report - need to report back to application?
 412  * @nlh: netlink message header
 413  *
 414  * Returns 1 if a report back to the application is requested.
 415  */
 416 static inline int nlmsg_report(struct nlmsghdr *nlh)
 417 {
 418         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 419 }
 420
 421 /**
 422  * nlmsg_for_each_attr - iterate over a stream of attributes
 423  * @pos: loop counter, set to current attribute
 424  * @nlh: netlink message header
 425  * @hdrlen: length of familiy specific header
 426  * @rem: initialized to len, holds bytes currently remaining in stream
 427  */
 428 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 429         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 430                           nlmsg_attrlen(nlh, hdrlen), rem)
 431
 432 #if 0
 433 /* FIXME: Enable once all users have been converted */
 434
 435 /**
 436  * __nlmsg_put - Add a new netlink message to an skb
 437  * @skb: socket buffer to store message in
 438  * @pid: netlink process id
 439  * @seq: sequence number of message
 440  * @type: message type
 441  * @payload: length of message payload
 442  * @flags: message flags
 443  *
 444  * The caller is responsible to ensure that the skb provides enough
 445  * tailroom for both the netlink header and payload.
 446  */
 447 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 448                                            u32 seq, int type, int payload,
 449                                            int flags)
 450 {
 451         struct nlmsghdr *nlh;
 452
 453         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 454         nlh->nlmsg_type = type;
 455         nlh->nlmsg_len = nlmsg_msg_size(payload);
 456         nlh->nlmsg_flags = flags;
 457         nlh->nlmsg_pid = pid;
 458         nlh->nlmsg_seq = seq;
 459
 460         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 461                nlmsg_padlen(payload));
 462
 463         return nlh;
 464 }
 465 #endif
 466
 467 /**
 468  * nlmsg_put - Add a new netlink message to an skb
 469  * @skb: socket buffer to store message in
 470  * @pid: netlink process id
 471  * @seq: sequence number of message
 472  * @type: message type
 473  * @payload: length of message payload
 474  * @flags: message flags
 475  *
 476  * Returns NULL if the tailroom of the skb is insufficient to store
 477  * the message header and payload.
 478  */
 479 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 480                                          int type, int payload, int flags)
 481 {
 482         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 483                 return NULL;
 484
 485         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 486 }
 487
 488 /**
 489  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 490  * @skb: socket buffer to store message in
 491  * @cb: netlink callback
 492  * @type: message type
 493  * @payload: length of message payload
 494  * @flags: message flags
 495  *
 496  * Returns NULL if the tailroom of the skb is insufficient to store
 497  * the message header and payload.
 498  */
 499 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 500                                                 struct netlink_callback *cb,
 501                                                 int type, int payload,
 502                                                 int flags)
 503 {
 504         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 505                          type, payload, flags);
 506 }
 507
 508 /**
 509  * nlmsg_new - Allocate a new netlink message
 510  * @payload: size of the message payload
 511  * @flags: the type of memory to allocate.
 512  *
 513  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 514  * and a good default is needed.
 515  */
 516 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 517 {
 518         return alloc_skb(nlmsg_total_size(payload), flags);
 519 }
 520
 521 /**
 522  * nlmsg_end - Finalize a netlink message
 523  * @skb: socket buffer the message is stored in
 524  * @nlh: netlink message header
 525  *
 526  * Corrects the netlink message header to include the appeneded
 527  * attributes. Only necessary if attributes have been added to
 528  * the message.
 529  *
 530  * Returns the total data length of the skb.
 531  */
 532 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 533 {
 534         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 535
 536         return skb->len;
 537 }
 538
 539 /**
 540  * nlmsg_get_pos - return current position in netlink message
 541  * @skb: socket buffer the message is stored in
 542  *
 543  * Returns a pointer to the current tail of the message.
 544  */
 545 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 546 {
 547         return skb_tail_pointer(skb);
 548 }
 549
 550 /**
 551  * nlmsg_trim - Trim message to a mark
 552  * @skb: socket buffer the message is stored in
 553  * @mark: mark to trim to
 554  *
 555  * Trims the message to the provided mark. Returns -1.
 556  */
 557 static inline int nlmsg_trim(struct sk_buff *skb, const void *mark)
 558 {
 559         if (mark)
 560                 skb_trim(skb, (unsigned char *) mark - skb->data);
 561
 562         return -1;
 563 }
 564
 565 /**
 566  * nlmsg_cancel - Cancel construction of a netlink message
 567  * @skb: socket buffer the message is stored in
 568  * @nlh: netlink message header
 569  *
 570  * Removes the complete netlink message including all
 571  * attributes from the socket buffer again. Returns -1.
 572  */
 573 static inline int nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 574 {
 575         return nlmsg_trim(skb, nlh);
 576 }
 577
 578 /**
 579  * nlmsg_free - free a netlink message
 580  * @skb: socket buffer of netlink message
 581  */
 582 static inline void nlmsg_free(struct sk_buff *skb)
 583 {
 584         kfree_skb(skb);
 585 }
 586
 587 /**
 588  * nlmsg_multicast - multicast a netlink message
 589  * @sk: netlink socket to spread messages to
 590  * @skb: netlink message as socket buffer
 591  * @pid: own netlink pid to avoid sending to yourself
 592  * @group: multicast group id
 593  * @flags: allocation flags
 594  */
 595 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 596                                   u32 pid, unsigned int group, gfp_t flags)
 597 {
 598         int err;
 599
 600         NETLINK_CB(skb).dst_group = group;
 601
 602         err = netlink_broadcast(sk, skb, pid, group, flags);
 603         if (err > 0)
 604                 err = 0;
 605
 606         return err;
 607 }
 608
 609 /**
 610  * nlmsg_unicast - unicast a netlink message
 611  * @sk: netlink socket to spread message to
 612  * @skb: netlink message as socket buffer
 613  * @pid: netlink pid of the destination socket
 614  */
 615 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 616 {
 617         int err;
 618
 619         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 620         if (err > 0)
 621                 err = 0;
 622
 623         return err;
 624 }
 625
 626 /**
 627  * nlmsg_for_each_msg - iterate over a stream of messages
 628  * @pos: loop counter, set to current message
 629  * @head: head of message stream
 630  * @len: length of message stream
 631  * @rem: initialized to len, holds bytes currently remaining in stream
 632  */
 633 #define nlmsg_for_each_msg(pos, head, len, rem) \
 634         for (pos = head, rem = len; \
 635              nlmsg_ok(pos, rem); \
 636              pos = nlmsg_next(pos, &(rem)))
 637
 638 /**************************************************************************
 639  * Netlink Attributes
 640  **************************************************************************/
 641
 642 /**
 643  * nla_attr_size - length of attribute not including padding
 644  * @payload: length of payload
 645  */
 646 static inline int nla_attr_size(int payload)
 647 {
 648         return NLA_HDRLEN + payload;
 649 }
 650
 651 /**
 652  * nla_total_size - total length of attribute including padding
 653  * @payload: length of payload
 654  */
 655 static inline int nla_total_size(int payload)
 656 {
 657         return NLA_ALIGN(nla_attr_size(payload));
 658 }
 659
 660 /**
 661  * nla_padlen - length of padding at the tail of attribute
 662  * @payload: length of payload
 663  */
 664 static inline int nla_padlen(int payload)
 665 {
 666         return nla_total_size(payload) - nla_attr_size(payload);
 667 }
 668
 669 /**
 670  * nla_data - head of payload
 671  * @nla: netlink attribute
 672  */
 673 static inline void *nla_data(const struct nlattr *nla)
 674 {
 675         return (char *) nla + NLA_HDRLEN;
 676 }
 677
 678 /**
 679  * nla_len - length of payload
 680  * @nla: netlink attribute
 681  */
 682 static inline int nla_len(const struct nlattr *nla)
 683 {
 684         return nla->nla_len - NLA_HDRLEN;
 685 }
 686
 687 /**
 688  * nla_ok - check if the netlink attribute fits into the remaining bytes
 689  * @nla: netlink attribute
 690  * @remaining: number of bytes remaining in attribute stream
 691  */
 692 static inline int nla_ok(const struct nlattr *nla, int remaining)
 693 {
 694         return remaining >= sizeof(*nla) &&
 695                nla->nla_len >= sizeof(*nla) &&
 696                nla->nla_len <= remaining;
 697 }
 698
 699 /**
 700  * nla_next - next netlink attribte in attribute stream
 701  * @nla: netlink attribute
 702  * @remaining: number of bytes remaining in attribute stream
 703  *
 704  * Returns the next netlink attribute in the attribute stream and
 705  * decrements remaining by the size of the current attribute.
 706  */
 707 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 708 {
 709         int totlen = NLA_ALIGN(nla->nla_len);
 710
 711         *remaining -= totlen;
 712         return (struct nlattr *) ((char *) nla + totlen);
 713 }
 714
 715 /**
 716  * nla_find_nested - find attribute in a set of nested attributes
 717  * @nla: attribute containing the nested attributes
 718  * @attrtype: type of attribute to look for
 719  *
 720  * Returns the first attribute which matches the specified type.
 721  */
 722 static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
 723 {
 724         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 725 }
 726
 727 /**
 728  * nla_parse_nested - parse nested attributes
 729  * @tb: destination array with maxtype+1 elements
 730  * @maxtype: maximum attribute type to be expected
 731  * @nla: attribute containing the nested attributes
 732  * @policy: validation policy
 733  *
 734  * See nla_parse()
 735  */
 736 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 737                                    struct nlattr *nla,
 738                                    const struct nla_policy *policy)
 739 {
 740         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 741 }
 742
 743 /**
 744  * nla_parse_nested_compat - parse nested compat attributes
 745  * @tb: destination array with maxtype+1 elements
 746  * @maxtype: maximum attribute type to be expected
 747  * @nla: attribute containing the nested attributes
 748  * @data: pointer to point to contained structure
 749  * @len: length of contained structure
 750  * @policy: validation policy
 751  *
 752  * Parse a nested compat attribute. The compat attribute contains a structure
 753  * and optionally a set of nested attributes. On success the data pointer
 754  * points to the nested data and tb contains the parsed attributes
 755  * (see nla_parse).
 756  */
 757 static inline int __nla_parse_nested_compat(struct nlattr *tb[], int maxtype,
 758                                             struct nlattr *nla,
 759                                             const struct nla_policy *policy,
 760                                             int len)
 761 {
 762         if (nla_len(nla) < len)
 763                 return -1;
 764         if (nla_len(nla) >= NLA_ALIGN(len) + sizeof(struct nlattr))
 765                 return nla_parse_nested(tb, maxtype,
 766                                         nla_data(nla) + NLA_ALIGN(len),
 767                                         policy);
 768         memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
 769         return 0;
 770 }
 771
 772 #define nla_parse_nested_compat(tb, maxtype, nla, policy, data, len) \
 773 ({      data = nla_len(nla) >= len ? nla_data(nla) : NULL; \
 774         __nla_parse_nested_compat(tb, maxtype, nla, policy, len); })
 775 /**
 776  * nla_put_u8 - Add a u16 netlink attribute to a socket buffer
 777  * @skb: socket buffer to add attribute to
 778  * @attrtype: attribute type
 779  * @value: numeric value
 780  */
 781 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 782 {
 783         return nla_put(skb, attrtype, sizeof(u8), &value);
 784 }
 785
 786 /**
 787  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 788  * @skb: socket buffer to add attribute to
 789  * @attrtype: attribute type
 790  * @value: numeric value
 791  */
 792 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 793 {
 794         return nla_put(skb, attrtype, sizeof(u16), &value);
 795 }
 796
 797 /**
 798  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 799  * @skb: socket buffer to add attribute to
 800  * @attrtype: attribute type
 801  * @value: numeric value
 802  */
 803 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 804 {
 805         return nla_put(skb, attrtype, sizeof(u32), &value);
 806 }
 807
 808 /**
 809  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 810  * @skb: socket buffer to add attribute to
 811  * @attrtype: attribute type
 812  * @value: numeric value
 813  */
 814 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 815 {
 816         return nla_put(skb, attrtype, sizeof(u64), &value);
 817 }
 818
 819 /**
 820  * nla_put_string - Add a string netlink attribute to a socket buffer
 821  * @skb: socket buffer to add attribute to
 822  * @attrtype: attribute type
 823  * @str: NUL terminated string
 824  */
 825 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 826                                  const char *str)
 827 {
 828         return nla_put(skb, attrtype, strlen(str) + 1, str);
 829 }
 830
 831 /**
 832  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 833  * @skb: socket buffer to add attribute to
 834  * @attrtype: attribute type
 835  */
 836 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 837 {
 838         return nla_put(skb, attrtype, 0, NULL);
 839 }
 840
 841 /**
 842  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 843  * @skb: socket buffer to add attribute to
 844  * @attrtype: attribute type
 845  * @jiffies: number of msecs in jiffies
 846  */
 847 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 848                                 unsigned long jiffies)
 849 {
 850         u64 tmp = jiffies_to_msecs(jiffies);
 851         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 852 }
 853
 854 #define NLA_PUT(skb, attrtype, attrlen, data) \
 855         do { \
 856                 if (nla_put(skb, attrtype, attrlen, data) < 0) \
 857                         goto nla_put_failure; \
 858         } while(0)
 859
 860 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 861         do { \
 862                 type __tmp = value; \
 863                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 864         } while(0)
 865
 866 #define NLA_PUT_U8(skb, attrtype, value) \
 867         NLA_PUT_TYPE(skb, u8, attrtype, value)
 868
 869 #define NLA_PUT_U16(skb, attrtype, value) \
 870         NLA_PUT_TYPE(skb, u16, attrtype, value)
 871
 872 #define NLA_PUT_LE16(skb, attrtype, value) \
 873         NLA_PUT_TYPE(skb, __le16, attrtype, value)
 874
 875 #define NLA_PUT_U32(skb, attrtype, value) \
 876         NLA_PUT_TYPE(skb, u32, attrtype, value)
 877
 878 #define NLA_PUT_BE32(skb, attrtype, value) \
 879         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 880
 881 #define NLA_PUT_U64(skb, attrtype, value) \
 882         NLA_PUT_TYPE(skb, u64, attrtype, value)
 883
 884 #define NLA_PUT_STRING(skb, attrtype, value) \
 885         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 886
 887 #define NLA_PUT_FLAG(skb, attrtype) \
 888         NLA_PUT(skb, attrtype, 0, NULL)
 889
 890 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 891         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 892
 893 /**
 894  * nla_get_u32 - return payload of u32 attribute
 895  * @nla: u32 netlink attribute
 896  */
 897 static inline u32 nla_get_u32(struct nlattr *nla)
 898 {
 899         return *(u32 *) nla_data(nla);
 900 }
 901
 902 /**
 903  * nla_get_be32 - return payload of __be32 attribute
 904  * @nla: __be32 netlink attribute
 905  */
 906 static inline __be32 nla_get_be32(struct nlattr *nla)
 907 {
 908         return *(__be32 *) nla_data(nla);
 909 }
 910
 911 /**
 912  * nla_get_u16 - return payload of u16 attribute
 913  * @nla: u16 netlink attribute
 914  */
 915 static inline u16 nla_get_u16(struct nlattr *nla)
 916 {
 917         return *(u16 *) nla_data(nla);
 918 }
 919
 920 /**
 921  * nla_get_le16 - return payload of __le16 attribute
 922  * @nla: __le16 netlink attribute
 923  */
 924 static inline __le16 nla_get_le16(struct nlattr *nla)
 925 {
 926         return *(__le16 *) nla_data(nla);
 927 }
 928
 929 /**
 930  * nla_get_u8 - return payload of u8 attribute
 931  * @nla: u8 netlink attribute
 932  */
 933 static inline u8 nla_get_u8(struct nlattr *nla)
 934 {
 935         return *(u8 *) nla_data(nla);
 936 }
 937
 938 /**
 939  * nla_get_u64 - return payload of u64 attribute
 940  * @nla: u64 netlink attribute
 941  */
 942 static inline u64 nla_get_u64(struct nlattr *nla)
 943 {
 944         u64 tmp;
 945
 946         nla_memcpy(&tmp, nla, sizeof(tmp));
 947
 948         return tmp;
 949 }
 950
 951 /**
 952  * nla_get_flag - return payload of flag attribute
 953  * @nla: flag netlink attribute
 954  */
 955 static inline int nla_get_flag(struct nlattr *nla)
 956 {
 957         return !!nla;
 958 }
 959
 960 /**
 961  * nla_get_msecs - return payload of msecs attribute
 962  * @nla: msecs netlink attribute
 963  *
 964  * Returns the number of milliseconds in jiffies.
 965  */
 966 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 967 {
 968         u64 msecs = nla_get_u64(nla);
 969
 970         return msecs_to_jiffies((unsigned long) msecs);
 971 }
 972
 973 /**
 974  * nla_nest_start - Start a new level of nested attributes
 975  * @skb: socket buffer to add attributes to
 976  * @attrtype: attribute type of container
 977  *
 978  * Returns the container attribute
 979  */
 980 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
 981 {
 982         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
 983
 984         if (nla_put(skb, attrtype, 0, NULL) < 0)
 985                 return NULL;
 986
 987         return start;
 988 }
 989
 990 /**
 991  * nla_nest_end - Finalize nesting of attributes
 992  * @skb: socket buffer the attribtues are stored in
 993  * @start: container attribute
 994  *
 995  * Corrects the container attribute header to include the all
 996  * appeneded attributes.
 997  *
 998  * Returns the total data length of the skb.
 999  */
1000 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1001 {
1002         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1003         return skb->len;
1004 }
1005
1006 /**
1007  * nla_nest_compat_start - Start a new level of nested compat attributes
1008  * @skb: socket buffer to add attributes to
1009  * @attrtype: attribute type of container
1010  * @attrlen: length of structure
1011  * @data: pointer to structure
1012  *
1013  * Start a nested compat attribute that contains both a structure and
1014  * a set of nested attributes.
1015  *
1016  * Returns the container attribute
1017  */
1018 static inline struct nlattr *nla_nest_compat_start(struct sk_buff *skb,
1019                                                    int attrtype, int attrlen,
1020                                                    const void *data)
1021 {
1022         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1023
1024         if (nla_put(skb, attrtype, attrlen, data) < 0)
1025                 return NULL;
1026         if (nla_nest_start(skb, attrtype) == NULL) {
1027                 nlmsg_trim(skb, start);
1028                 return NULL;
1029         }
1030         return start;
1031 }
1032
1033 /**
1034  * nla_nest_compat_end - Finalize nesting of compat attributes
1035  * @skb: socket buffer the attribtues are stored in
1036  * @start: container attribute
1037  *
1038  * Corrects the container attribute header to include the all
1039  * appeneded attributes.
1040  *
1041  * Returns the total data length of the skb.
1042  */
1043 static inline int nla_nest_compat_end(struct sk_buff *skb, struct nlattr *start)
1044 {
1045         struct nlattr *nest = (void *)start + NLMSG_ALIGN(start->nla_len);
1046
1047         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1048         return nla_nest_end(skb, nest);
1049 }
1050
1051 /**
1052  * nla_nest_cancel - Cancel nesting of attributes
1053  * @skb: socket buffer the message is stored in
1054  * @start: container attribute
1055  *
1056  * Removes the container attribute and including all nested
1057  * attributes. Returns -1.
1058  */
1059 static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1060 {
1061         return nlmsg_trim(skb, start);
1062 }
1063
1064 /**
1065  * nla_validate_nested - Validate a stream of nested attributes
1066  * @start: container attribute
1067  * @maxtype: maximum attribute type to be expected
1068  * @policy: validation policy
1069  *
1070  * Validates all attributes in the nested attribute stream against the
1071  * specified policy. Attributes with a type exceeding maxtype will be
1072  * ignored. See documenation of struct nla_policy for more details.
1073  *
1074  * Returns 0 on success or a negative error code.
1075  */
1076 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
1077                                       const struct nla_policy *policy)
1078 {
1079         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1080 }
1081
1082 /**
1083  * nla_for_each_attr - iterate over a stream of attributes
1084  * @pos: loop counter, set to current attribute
1085  * @head: head of attribute stream
1086  * @len: length of attribute stream
1087  * @rem: initialized to len, holds bytes currently remaining in stream
1088  */
1089 #define nla_for_each_attr(pos, head, len, rem) \
1090         for (pos = head, rem = len; \
1091              nla_ok(pos, rem); \
1092              pos = nla_next(pos, &(rem)))
1093
1094 /**
1095  * nla_for_each_nested - iterate over nested attributes
1096  * @pos: loop counter, set to current attribute
1097  * @nla: attribute containing the nested attributes
1098  * @rem: initialized to len, holds bytes currently remaining in stream
1099  */
1100 #define nla_for_each_nested(pos, nla, rem) \
1101         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1102
1103 #endif