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()                        finalize 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 attribute 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  *   nla_append(skb, len, data)         append data to skb
  95  *
  96  * Attribute Construction for Basic Types:
  97  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  98  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
  99  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
 100  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
 101  *   nla_put_string(skb, type, str)     add string attribute to skb
 102  *   nla_put_flag(skb, type)            add flag attribute to skb
 103  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 104  *
 105  * Exceptions Based Attribute Construction:
 106  *   NLA_PUT(skb, type, len, data)      add attribute to skb
 107  *   NLA_PUT_U8(skb, type, value)       add u8 attribute to skb
 108  *   NLA_PUT_U16(skb, type, value)      add u16 attribute to skb
 109  *   NLA_PUT_U32(skb, type, value)      add u32 attribute to skb
 110  *   NLA_PUT_U64(skb, type, value)      add u64 attribute to skb
 111  *   NLA_PUT_STRING(skb, type, str)     add string attribute to skb
 112  *   NLA_PUT_FLAG(skb, type)            add flag attribute to skb
 113  *   NLA_PUT_MSECS(skb, type, jiffies)  add msecs attribute to skb
 114  *
 115  *   The meaning of these functions is equal to their lower case
 116  *   variants but they jump to the label nla_put_failure in case
 117  *   of a failure.
 118  *
 119  * Nested Attributes Construction:
 120  *   nla_nest_start(skb, type)          start a nested attribute
 121  *   nla_nest_end(skb, nla)             finalize a nested attribute
 122  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 123  *
 124  * Attribute Length Calculations:
 125  *   nla_attr_size(payload)             length of attribute w/o padding
 126  *   nla_total_size(payload)            length of attribute w/ padding
 127  *   nla_padlen(payload)                length of padding
 128  *
 129  * Attribute Payload Access:
 130  *   nla_data(nla)                      head of attribute payload
 131  *   nla_len(nla)                       length of attribute payload
 132  *
 133  * Attribute Payload Access for Basic Types:
 134  *   nla_get_u8(nla)                    get payload for a u8 attribute
 135  *   nla_get_u16(nla)                   get payload for a u16 attribute
 136  *   nla_get_u32(nla)                   get payload for a u32 attribute
 137  *   nla_get_u64(nla)                   get payload for a u64 attribute
 138  *   nla_get_flag(nla)                  return 1 if flag is true
 139  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 140  *
 141  * Attribute Misc:
 142  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 143  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 144  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 145  *   nla_strcmp(nla, str)               compare attribute with string
 146  *
 147  * Attribute Parsing:
 148  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 149  *   nla_next(nla, remaining)           get next netlink attribute
 150  *   nla_validate()                     validate a stream of attributes
 151  *   nla_validate_nested()              validate a stream of nested attributes
 152  *   nla_find()                         find attribute in stream of attributes
 153  *   nla_find_nested()                  find attribute in nested attributes
 154  *   nla_parse()                        parse and validate stream of attrs
 155  *   nla_parse_nested()                 parse nested attribuets
 156  *   nla_for_each_attr()                loop over all attributes
 157  *   nla_for_each_nested()              loop over the nested attributes
 158  *=========================================================================
 159  */
 160
 161  /**
 162   * Standard attribute types to specify validation policy
 163   */
 164 enum {
 165         NLA_UNSPEC,
 166         NLA_U8,
 167         NLA_U16,
 168         NLA_U32,
 169         NLA_U64,
 170         NLA_STRING,
 171         NLA_FLAG,
 172         NLA_MSECS,
 173         NLA_NESTED,
 174         NLA_NESTED_COMPAT,
 175         NLA_NUL_STRING,
 176         NLA_BINARY,
 177         __NLA_TYPE_MAX,
 178 };
 179
 180 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 181
 182 /**
 183  * struct nla_policy - attribute validation policy
 184  * @type: Type of attribute or NLA_UNSPEC
 185  * @len: Type specific length of payload
 186  *
 187  * Policies are defined as arrays of this struct, the array must be
 188  * accessible by attribute type up to the highest identifier to be expected.
 189  *
 190  * Meaning of `len' field:
 191  *    NLA_STRING           Maximum length of string
 192  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 193  *    NLA_FLAG             Unused
 194  *    NLA_BINARY           Maximum length of attribute payload
 195  *    NLA_NESTED           Don't use `len' field -- length verification is
 196  *                         done by checking len of nested header (or empty)
 197  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 198  *    NLA_U8, NLA_U16,
 199  *    NLA_U32, NLA_U64,
 200  *    NLA_MSECS            Leaving the length field zero will verify the
 201  *                         given type fits, using it verifies minimum length
 202  *                         just like "All other"
 203  *    All other            Minimum length of attribute payload
 204  *
 205  * Example:
 206  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 207  *      [ATTR_FOO] = { .type = NLA_U16 },
 208  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 209  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 210  * };
 211  */
 212 struct nla_policy {
 213         u16             type;
 214         u16             len;
 215 };
 216
 217 /**
 218  * struct nl_info - netlink source information
 219  * @nlh: Netlink message header of original request
 220  * @pid: Netlink PID of requesting application
 221  */
 222 struct nl_info {
 223         struct nlmsghdr         *nlh;
 224         struct net              *nl_net;
 225         u32                     pid;
 226 };
 227
 228 extern int              netlink_rcv_skb(struct sk_buff *skb,
 229                                         int (*cb)(struct sk_buff *,
 230                                                   struct nlmsghdr *));
 231 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 232                                      u32 pid, unsigned int group, int report,
 233                                      gfp_t flags);
 234
 235 extern int              nla_validate(const struct nlattr *head,
 236                                      int len, int maxtype,
 237                                      const struct nla_policy *policy);
 238 extern int              nla_parse(struct nlattr **tb, int maxtype,
 239                                   const struct nlattr *head, int len,
 240                                   const struct nla_policy *policy);
 241 extern int              nla_policy_len(const struct nla_policy *, int);
 242 extern struct nlattr *  nla_find(const struct nlattr *head,
 243                                  int len, int attrtype);
 244 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 245                                     size_t dstsize);
 246 extern int              nla_memcpy(void *dest, const struct nlattr *src, int count);
 247 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 248                                    size_t size);
 249 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 250 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 251                                       int attrlen);
 252 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 253 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 254                                     int attrlen);
 255 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 256 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 257                                   int attrlen, const void *data);
 258 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 259                                         const void *data);
 260 extern int              nla_put(struct sk_buff *skb, int attrtype,
 261                                 int attrlen, const void *data);
 262 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 263                                       const void *data);
 264 extern int              nla_append(struct sk_buff *skb, int attrlen,
 265                                    const void *data);
 266
 267 /**************************************************************************
 268  * Netlink Messages
 269  **************************************************************************/
 270
 271 /**
 272  * nlmsg_msg_size - length of netlink message not including padding
 273  * @payload: length of message payload
 274  */
 275 static inline int nlmsg_msg_size(int payload)
 276 {
 277         return NLMSG_HDRLEN + payload;
 278 }
 279
 280 /**
 281  * nlmsg_total_size - length of netlink message including padding
 282  * @payload: length of message payload
 283  */
 284 static inline int nlmsg_total_size(int payload)
 285 {
 286         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 287 }
 288
 289 /**
 290  * nlmsg_padlen - length of padding at the message's tail
 291  * @payload: length of message payload
 292  */
 293 static inline int nlmsg_padlen(int payload)
 294 {
 295         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 296 }
 297
 298 /**
 299  * nlmsg_data - head of message payload
 300  * @nlh: netlink message header
 301  */
 302 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 303 {
 304         return (unsigned char *) nlh + NLMSG_HDRLEN;
 305 }
 306
 307 /**
 308  * nlmsg_len - length of message payload
 309  * @nlh: netlink message header
 310  */
 311 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 312 {
 313         return nlh->nlmsg_len - NLMSG_HDRLEN;
 314 }
 315
 316 /**
 317  * nlmsg_attrdata - head of attributes data
 318  * @nlh: netlink message header
 319  * @hdrlen: length of family specific header
 320  */
 321 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 322                                             int hdrlen)
 323 {
 324         unsigned char *data = nlmsg_data(nlh);
 325         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 326 }
 327
 328 /**
 329  * nlmsg_attrlen - length of attributes data
 330  * @nlh: netlink message header
 331  * @hdrlen: length of family specific header
 332  */
 333 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 334 {
 335         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 336 }
 337
 338 /**
 339  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 340  * @nlh: netlink message header
 341  * @remaining: number of bytes remaining in message stream
 342  */
 343 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 344 {
 345         return (remaining >= (int) sizeof(struct nlmsghdr) &&
 346                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 347                 nlh->nlmsg_len <= remaining);
 348 }
 349
 350 /**
 351  * nlmsg_next - next netlink message in message stream
 352  * @nlh: netlink message header
 353  * @remaining: number of bytes remaining in message stream
 354  *
 355  * Returns the next netlink message in the message stream and
 356  * decrements remaining by the size of the current message.
 357  */
 358 static inline struct nlmsghdr *
 359 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 360 {
 361         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 362
 363         *remaining -= totlen;
 364
 365         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 366 }
 367
 368 /**
 369  * nlmsg_parse - parse attributes of a netlink message
 370  * @nlh: netlink message header
 371  * @hdrlen: length of family specific header
 372  * @tb: destination array with maxtype+1 elements
 373  * @maxtype: maximum attribute type to be expected
 374  * @policy: validation policy
 375  *
 376  * See nla_parse()
 377  */
 378 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 379                               struct nlattr *tb[], int maxtype,
 380                               const struct nla_policy *policy)
 381 {
 382         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 383                 return -EINVAL;
 384
 385         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 386                          nlmsg_attrlen(nlh, hdrlen), policy);
 387 }
 388
 389 /**
 390  * nlmsg_find_attr - find a specific attribute in a netlink message
 391  * @nlh: netlink message header
 392  * @hdrlen: length of familiy specific header
 393  * @attrtype: type of attribute to look for
 394  *
 395  * Returns the first attribute which matches the specified type.
 396  */
 397 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 398                                              int hdrlen, int attrtype)
 399 {
 400         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 401                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 402 }
 403
 404 /**
 405  * nlmsg_validate - validate a netlink message including attributes
 406  * @nlh: netlinket message header
 407  * @hdrlen: length of familiy specific header
 408  * @maxtype: maximum attribute type to be expected
 409  * @policy: validation policy
 410  */
 411 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 412                                  int hdrlen, int maxtype,
 413                                  const struct nla_policy *policy)
 414 {
 415         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 416                 return -EINVAL;
 417
 418         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 419                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 420 }
 421
 422 /**
 423  * nlmsg_report - need to report back to application?
 424  * @nlh: netlink message header
 425  *
 426  * Returns 1 if a report back to the application is requested.
 427  */
 428 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 429 {
 430         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 431 }
 432
 433 /**
 434  * nlmsg_for_each_attr - iterate over a stream of attributes
 435  * @pos: loop counter, set to current attribute
 436  * @nlh: netlink message header
 437  * @hdrlen: length of familiy specific header
 438  * @rem: initialized to len, holds bytes currently remaining in stream
 439  */
 440 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 441         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 442                           nlmsg_attrlen(nlh, hdrlen), rem)
 443
 444 #if 0
 445 /* FIXME: Enable once all users have been converted */
 446
 447 /**
 448  * __nlmsg_put - Add a new netlink message to an skb
 449  * @skb: socket buffer to store message in
 450  * @pid: netlink process id
 451  * @seq: sequence number of message
 452  * @type: message type
 453  * @payload: length of message payload
 454  * @flags: message flags
 455  *
 456  * The caller is responsible to ensure that the skb provides enough
 457  * tailroom for both the netlink header and payload.
 458  */
 459 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 460                                            u32 seq, int type, int payload,
 461                                            int flags)
 462 {
 463         struct nlmsghdr *nlh;
 464
 465         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 466         nlh->nlmsg_type = type;
 467         nlh->nlmsg_len = nlmsg_msg_size(payload);
 468         nlh->nlmsg_flags = flags;
 469         nlh->nlmsg_pid = pid;
 470         nlh->nlmsg_seq = seq;
 471
 472         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 473                nlmsg_padlen(payload));
 474
 475         return nlh;
 476 }
 477 #endif
 478
 479 /**
 480  * nlmsg_put - Add a new netlink message to an skb
 481  * @skb: socket buffer to store message in
 482  * @pid: netlink process id
 483  * @seq: sequence number of message
 484  * @type: message type
 485  * @payload: length of message payload
 486  * @flags: message flags
 487  *
 488  * Returns NULL if the tailroom of the skb is insufficient to store
 489  * the message header and payload.
 490  */
 491 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
 492                                          int type, int payload, int flags)
 493 {
 494         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 495                 return NULL;
 496
 497         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 498 }
 499
 500 /**
 501  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 502  * @skb: socket buffer to store message in
 503  * @cb: netlink callback
 504  * @type: message type
 505  * @payload: length of message payload
 506  * @flags: message flags
 507  *
 508  * Returns NULL if the tailroom of the skb is insufficient to store
 509  * the message header and payload.
 510  */
 511 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 512                                                 struct netlink_callback *cb,
 513                                                 int type, int payload,
 514                                                 int flags)
 515 {
 516         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 517                          type, payload, flags);
 518 }
 519
 520 /**
 521  * nlmsg_new - Allocate a new netlink message
 522  * @payload: size of the message payload
 523  * @flags: the type of memory to allocate.
 524  *
 525  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 526  * and a good default is needed.
 527  */
 528 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 529 {
 530         return alloc_skb(nlmsg_total_size(payload), flags);
 531 }
 532
 533 /**
 534  * nlmsg_end - Finalize a netlink message
 535  * @skb: socket buffer the message is stored in
 536  * @nlh: netlink message header
 537  *
 538  * Corrects the netlink message header to include the appeneded
 539  * attributes. Only necessary if attributes have been added to
 540  * the message.
 541  *
 542  * Returns the total data length of the skb.
 543  */
 544 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 545 {
 546         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 547
 548         return skb->len;
 549 }
 550
 551 /**
 552  * nlmsg_get_pos - return current position in netlink message
 553  * @skb: socket buffer the message is stored in
 554  *
 555  * Returns a pointer to the current tail of the message.
 556  */
 557 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 558 {
 559         return skb_tail_pointer(skb);
 560 }
 561
 562 /**
 563  * nlmsg_trim - Trim message to a mark
 564  * @skb: socket buffer the message is stored in
 565  * @mark: mark to trim to
 566  *
 567  * Trims the message to the provided mark.
 568  */
 569 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 570 {
 571         if (mark)
 572                 skb_trim(skb, (unsigned char *) mark - skb->data);
 573 }
 574
 575 /**
 576  * nlmsg_cancel - Cancel construction of a netlink message
 577  * @skb: socket buffer the message is stored in
 578  * @nlh: netlink message header
 579  *
 580  * Removes the complete netlink message including all
 581  * attributes from the socket buffer again.
 582  */
 583 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 584 {
 585         nlmsg_trim(skb, nlh);
 586 }
 587
 588 /**
 589  * nlmsg_free - free a netlink message
 590  * @skb: socket buffer of netlink message
 591  */
 592 static inline void nlmsg_free(struct sk_buff *skb)
 593 {
 594         kfree_skb(skb);
 595 }
 596
 597 /**
 598  * nlmsg_multicast - multicast a netlink message
 599  * @sk: netlink socket to spread messages to
 600  * @skb: netlink message as socket buffer
 601  * @pid: own netlink pid to avoid sending to yourself
 602  * @group: multicast group id
 603  * @flags: allocation flags
 604  */
 605 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 606                                   u32 pid, unsigned int group, gfp_t flags)
 607 {
 608         int err;
 609
 610         NETLINK_CB(skb).dst_group = group;
 611
 612         err = netlink_broadcast(sk, skb, pid, group, flags);
 613         if (err > 0)
 614                 err = 0;
 615
 616         return err;
 617 }
 618
 619 /**
 620  * nlmsg_unicast - unicast a netlink message
 621  * @sk: netlink socket to spread message to
 622  * @skb: netlink message as socket buffer
 623  * @pid: netlink pid of the destination socket
 624  */
 625 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 626 {
 627         int err;
 628
 629         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 630         if (err > 0)
 631                 err = 0;
 632
 633         return err;
 634 }
 635
 636 /**
 637  * nlmsg_for_each_msg - iterate over a stream of messages
 638  * @pos: loop counter, set to current message
 639  * @head: head of message stream
 640  * @len: length of message stream
 641  * @rem: initialized to len, holds bytes currently remaining in stream
 642  */
 643 #define nlmsg_for_each_msg(pos, head, len, rem) \
 644         for (pos = head, rem = len; \
 645              nlmsg_ok(pos, rem); \
 646              pos = nlmsg_next(pos, &(rem)))
 647
 648 /**
 649  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 650  * @cb: netlink callback structure that stores the sequence number
 651  * @nlh: netlink message header to write the flag to
 652  *
 653  * This function checks if the sequence (generation) number changed during dump
 654  * and if it did, advertises it in the netlink message header.
 655  *
 656  * The correct way to use it is to set cb->seq to the generation counter when
 657  * all locks for dumping have been acquired, and then call this function for
 658  * each message that is generated.
 659  *
 660  * Note that due to initialisation concerns, 0 is an invalid sequence number
 661  * and must not be used by code that uses this functionality.
 662  */
 663 static inline void
 664 nl_dump_check_consistent(struct netlink_callback *cb,
 665                          struct nlmsghdr *nlh)
 666 {
 667         if (cb->prev_seq && cb->seq != cb->prev_seq)
 668                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 669         cb->prev_seq = cb->seq;
 670 }
 671
 672 /**************************************************************************
 673  * Netlink Attributes
 674  **************************************************************************/
 675
 676 /**
 677  * nla_attr_size - length of attribute not including padding
 678  * @payload: length of payload
 679  */
 680 static inline int nla_attr_size(int payload)
 681 {
 682         return NLA_HDRLEN + payload;
 683 }
 684
 685 /**
 686  * nla_total_size - total length of attribute including padding
 687  * @payload: length of payload
 688  */
 689 static inline int nla_total_size(int payload)
 690 {
 691         return NLA_ALIGN(nla_attr_size(payload));
 692 }
 693
 694 /**
 695  * nla_padlen - length of padding at the tail of attribute
 696  * @payload: length of payload
 697  */
 698 static inline int nla_padlen(int payload)
 699 {
 700         return nla_total_size(payload) - nla_attr_size(payload);
 701 }
 702
 703 /**
 704  * nla_type - attribute type
 705  * @nla: netlink attribute
 706  */
 707 static inline int nla_type(const struct nlattr *nla)
 708 {
 709         return nla->nla_type & NLA_TYPE_MASK;
 710 }
 711
 712 /**
 713  * nla_data - head of payload
 714  * @nla: netlink attribute
 715  */
 716 static inline void *nla_data(const struct nlattr *nla)
 717 {
 718         return (char *) nla + NLA_HDRLEN;
 719 }
 720
 721 /**
 722  * nla_len - length of payload
 723  * @nla: netlink attribute
 724  */
 725 static inline int nla_len(const struct nlattr *nla)
 726 {
 727         return nla->nla_len - NLA_HDRLEN;
 728 }
 729
 730 /**
 731  * nla_ok - check if the netlink attribute fits into the remaining bytes
 732  * @nla: netlink attribute
 733  * @remaining: number of bytes remaining in attribute stream
 734  */
 735 static inline int nla_ok(const struct nlattr *nla, int remaining)
 736 {
 737         return remaining >= (int) sizeof(*nla) &&
 738                nla->nla_len >= sizeof(*nla) &&
 739                nla->nla_len <= remaining;
 740 }
 741
 742 /**
 743  * nla_next - next netlink attribute in attribute stream
 744  * @nla: netlink attribute
 745  * @remaining: number of bytes remaining in attribute stream
 746  *
 747  * Returns the next netlink attribute in the attribute stream and
 748  * decrements remaining by the size of the current attribute.
 749  */
 750 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 751 {
 752         int totlen = NLA_ALIGN(nla->nla_len);
 753
 754         *remaining -= totlen;
 755         return (struct nlattr *) ((char *) nla + totlen);
 756 }
 757
 758 /**
 759  * nla_find_nested - find attribute in a set of nested attributes
 760  * @nla: attribute containing the nested attributes
 761  * @attrtype: type of attribute to look for
 762  *
 763  * Returns the first attribute which matches the specified type.
 764  */
 765 static inline struct nlattr *
 766 nla_find_nested(const struct nlattr *nla, int attrtype)
 767 {
 768         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 769 }
 770
 771 /**
 772  * nla_parse_nested - parse nested attributes
 773  * @tb: destination array with maxtype+1 elements
 774  * @maxtype: maximum attribute type to be expected
 775  * @nla: attribute containing the nested attributes
 776  * @policy: validation policy
 777  *
 778  * See nla_parse()
 779  */
 780 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 781                                    const struct nlattr *nla,
 782                                    const struct nla_policy *policy)
 783 {
 784         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 785 }
 786
 787 /**
 788  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 789  * @skb: socket buffer to add attribute to
 790  * @attrtype: attribute type
 791  * @value: numeric value
 792  */
 793 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 794 {
 795         return nla_put(skb, attrtype, sizeof(u8), &value);
 796 }
 797
 798 /**
 799  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 800  * @skb: socket buffer to add attribute to
 801  * @attrtype: attribute type
 802  * @value: numeric value
 803  */
 804 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 805 {
 806         return nla_put(skb, attrtype, sizeof(u16), &value);
 807 }
 808
 809 /**
 810  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 811  * @skb: socket buffer to add attribute to
 812  * @attrtype: attribute type
 813  * @value: numeric value
 814  */
 815 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 816 {
 817         return nla_put(skb, attrtype, sizeof(u32), &value);
 818 }
 819
 820 /**
 821  * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 822  * @skb: socket buffer to add attribute to
 823  * @attrtype: attribute type
 824  * @value: numeric value
 825  */
 826 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 827 {
 828         return nla_put(skb, attrtype, sizeof(u64), &value);
 829 }
 830
 831 /**
 832  * nla_put_string - Add a string netlink attribute to a socket buffer
 833  * @skb: socket buffer to add attribute to
 834  * @attrtype: attribute type
 835  * @str: NUL terminated string
 836  */
 837 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 838                                  const char *str)
 839 {
 840         return nla_put(skb, attrtype, strlen(str) + 1, str);
 841 }
 842
 843 /**
 844  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 845  * @skb: socket buffer to add attribute to
 846  * @attrtype: attribute type
 847  */
 848 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 849 {
 850         return nla_put(skb, attrtype, 0, NULL);
 851 }
 852
 853 /**
 854  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 855  * @skb: socket buffer to add attribute to
 856  * @attrtype: attribute type
 857  * @jiffies: number of msecs in jiffies
 858  */
 859 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 860                                 unsigned long jiffies)
 861 {
 862         u64 tmp = jiffies_to_msecs(jiffies);
 863         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 864 }
 865
 866 #define NLA_PUT(skb, attrtype, attrlen, data) \
 867         do { \
 868                 if (unlikely(nla_put(skb, attrtype, attrlen, data) < 0)) \
 869                         goto nla_put_failure; \
 870         } while(0)
 871
 872 #define NLA_PUT_TYPE(skb, type, attrtype, value) \
 873         do { \
 874                 type __tmp = value; \
 875                 NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
 876         } while(0)
 877
 878 #define NLA_PUT_U8(skb, attrtype, value) \
 879         NLA_PUT_TYPE(skb, u8, attrtype, value)
 880
 881 #define NLA_PUT_U16(skb, attrtype, value) \
 882         NLA_PUT_TYPE(skb, u16, attrtype, value)
 883
 884 #define NLA_PUT_LE16(skb, attrtype, value) \
 885         NLA_PUT_TYPE(skb, __le16, attrtype, value)
 886
 887 #define NLA_PUT_BE16(skb, attrtype, value) \
 888         NLA_PUT_TYPE(skb, __be16, attrtype, value)
 889
 890 #define NLA_PUT_NET16(skb, attrtype, value) \
 891         NLA_PUT_BE16(skb, attrtype | NLA_F_NET_BYTEORDER, value)
 892
 893 #define NLA_PUT_U32(skb, attrtype, value) \
 894         NLA_PUT_TYPE(skb, u32, attrtype, value)
 895
 896 #define NLA_PUT_BE32(skb, attrtype, value) \
 897         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 898
 899 #define NLA_PUT_NET32(skb, attrtype, value) \
 900         NLA_PUT_BE32(skb, attrtype | NLA_F_NET_BYTEORDER, value)
 901
 902 #define NLA_PUT_U64(skb, attrtype, value) \
 903         NLA_PUT_TYPE(skb, u64, attrtype, value)
 904
 905 #define NLA_PUT_BE64(skb, attrtype, value) \
 906         NLA_PUT_TYPE(skb, __be64, attrtype, value)
 907
 908 #define NLA_PUT_NET64(skb, attrtype, value) \
 909         NLA_PUT_BE64(skb, attrtype | NLA_F_NET_BYTEORDER, value)
 910
 911 #define NLA_PUT_STRING(skb, attrtype, value) \
 912         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 913
 914 #define NLA_PUT_FLAG(skb, attrtype) \
 915         NLA_PUT(skb, attrtype, 0, NULL)
 916
 917 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 918         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 919
 920 /**
 921  * nla_get_u32 - return payload of u32 attribute
 922  * @nla: u32 netlink attribute
 923  */
 924 static inline u32 nla_get_u32(const struct nlattr *nla)
 925 {
 926         return *(u32 *) nla_data(nla);
 927 }
 928
 929 /**
 930  * nla_get_be32 - return payload of __be32 attribute
 931  * @nla: __be32 netlink attribute
 932  */
 933 static inline __be32 nla_get_be32(const struct nlattr *nla)
 934 {
 935         return *(__be32 *) nla_data(nla);
 936 }
 937
 938 /**
 939  * nla_get_u16 - return payload of u16 attribute
 940  * @nla: u16 netlink attribute
 941  */
 942 static inline u16 nla_get_u16(const struct nlattr *nla)
 943 {
 944         return *(u16 *) nla_data(nla);
 945 }
 946
 947 /**
 948  * nla_get_be16 - return payload of __be16 attribute
 949  * @nla: __be16 netlink attribute
 950  */
 951 static inline __be16 nla_get_be16(const struct nlattr *nla)
 952 {
 953         return *(__be16 *) nla_data(nla);
 954 }
 955
 956 /**
 957  * nla_get_le16 - return payload of __le16 attribute
 958  * @nla: __le16 netlink attribute
 959  */
 960 static inline __le16 nla_get_le16(const struct nlattr *nla)
 961 {
 962         return *(__le16 *) nla_data(nla);
 963 }
 964
 965 /**
 966  * nla_get_u8 - return payload of u8 attribute
 967  * @nla: u8 netlink attribute
 968  */
 969 static inline u8 nla_get_u8(const struct nlattr *nla)
 970 {
 971         return *(u8 *) nla_data(nla);
 972 }
 973
 974 /**
 975  * nla_get_u64 - return payload of u64 attribute
 976  * @nla: u64 netlink attribute
 977  */
 978 static inline u64 nla_get_u64(const struct nlattr *nla)
 979 {
 980         u64 tmp;
 981
 982         nla_memcpy(&tmp, nla, sizeof(tmp));
 983
 984         return tmp;
 985 }
 986
 987 /**
 988  * nla_get_be64 - return payload of __be64 attribute
 989  * @nla: __be64 netlink attribute
 990  */
 991 static inline __be64 nla_get_be64(const struct nlattr *nla)
 992 {
 993         __be64 tmp;
 994
 995         nla_memcpy(&tmp, nla, sizeof(tmp));
 996
 997         return tmp;
 998 }
 999
1000 /**
1001  * nla_get_flag - return payload of flag attribute
1002  * @nla: flag netlink attribute
1003  */
1004 static inline int nla_get_flag(const struct nlattr *nla)
1005 {
1006         return !!nla;
1007 }
1008
1009 /**
1010  * nla_get_msecs - return payload of msecs attribute
1011  * @nla: msecs netlink attribute
1012  *
1013  * Returns the number of milliseconds in jiffies.
1014  */
1015 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1016 {
1017         u64 msecs = nla_get_u64(nla);
1018
1019         return msecs_to_jiffies((unsigned long) msecs);
1020 }
1021
1022 /**
1023  * nla_nest_start - Start a new level of nested attributes
1024  * @skb: socket buffer to add attributes to
1025  * @attrtype: attribute type of container
1026  *
1027  * Returns the container attribute
1028  */
1029 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1030 {
1031         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1032
1033         if (nla_put(skb, attrtype, 0, NULL) < 0)
1034                 return NULL;
1035
1036         return start;
1037 }
1038
1039 /**
1040  * nla_nest_end - Finalize nesting of attributes
1041  * @skb: socket buffer the attributes are stored in
1042  * @start: container attribute
1043  *
1044  * Corrects the container attribute header to include the all
1045  * appeneded attributes.
1046  *
1047  * Returns the total data length of the skb.
1048  */
1049 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1050 {
1051         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1052         return skb->len;
1053 }
1054
1055 /**
1056  * nla_nest_cancel - Cancel nesting of attributes
1057  * @skb: socket buffer the message is stored in
1058  * @start: container attribute
1059  *
1060  * Removes the container attribute and including all nested
1061  * attributes. Returns -EMSGSIZE
1062  */
1063 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1064 {
1065         nlmsg_trim(skb, start);
1066 }
1067
1068 /**
1069  * nla_validate_nested - Validate a stream of nested attributes
1070  * @start: container attribute
1071  * @maxtype: maximum attribute type to be expected
1072  * @policy: validation policy
1073  *
1074  * Validates all attributes in the nested attribute stream against the
1075  * specified policy. Attributes with a type exceeding maxtype will be
1076  * ignored. See documenation of struct nla_policy for more details.
1077  *
1078  * Returns 0 on success or a negative error code.
1079  */
1080 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1081                                       const struct nla_policy *policy)
1082 {
1083         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1084 }
1085
1086 /**
1087  * nla_for_each_attr - iterate over a stream of attributes
1088  * @pos: loop counter, set to current attribute
1089  * @head: head of attribute stream
1090  * @len: length of attribute stream
1091  * @rem: initialized to len, holds bytes currently remaining in stream
1092  */
1093 #define nla_for_each_attr(pos, head, len, rem) \
1094         for (pos = head, rem = len; \
1095              nla_ok(pos, rem); \
1096              pos = nla_next(pos, &(rem)))
1097
1098 /**
1099  * nla_for_each_nested - iterate over nested attributes
1100  * @pos: loop counter, set to current attribute
1101  * @nla: attribute containing the nested attributes
1102  * @rem: initialized to len, holds bytes currently remaining in stream
1103  */
1104 #define nla_for_each_nested(pos, nla, rem) \
1105         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1106
1107 #endif