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 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_compat_start(skb, type,   start a nested compat attribute
 123  *                         len, data)
 124  *   nla_nest_compat_end(skb, type)     finalize a nested compat attribute
 125  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 126  *
 127  * Attribute Length Calculations:
 128  *   nla_attr_size(payload)             length of attribute w/o padding
 129  *   nla_total_size(payload)            length of attribute w/ padding
 130  *   nla_padlen(payload)                length of padding
 131  *
 132  * Attribute Payload Access:
 133  *   nla_data(nla)                      head of attribute payload
 134  *   nla_len(nla)                       length of attribute payload
 135  *
 136  * Attribute Payload Access for Basic Types:
 137  *   nla_get_u8(nla)                    get payload for a u8 attribute
 138  *   nla_get_u16(nla)                   get payload for a u16 attribute
 139  *   nla_get_u32(nla)                   get payload for a u32 attribute
 140  *   nla_get_u64(nla)                   get payload for a u64 attribute
 141  *   nla_get_flag(nla)                  return 1 if flag is true
 142  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 143  *
 144  * Attribute Misc:
 145  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 146  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 147  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 148  *   nla_strcmp(nla, str)               compare attribute with string
 149  *
 150  * Attribute Parsing:
 151  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 152  *   nla_next(nla, remaining)           get next netlink attribute
 153  *   nla_validate()                     validate a stream of attributes
 154  *   nla_validate_nested()              validate a stream of nested attributes
 155  *   nla_find()                         find attribute in stream of attributes
 156  *   nla_find_nested()                  find attribute in nested attributes
 157  *   nla_parse()                        parse and validate stream of attrs
 158  *   nla_parse_nested()                 parse nested attribuets
 159  *   nla_parse_nested_compat()          parse nested compat attributes
 160  *   nla_for_each_attr()                loop over all attributes
 161  *   nla_for_each_nested()              loop over the nested attributes
 162  *=========================================================================
 163  */
 164
 165  /**
 166   * Standard attribute types to specify validation policy
 167   */
 168 enum {
 169         NLA_UNSPEC,
 170         NLA_U8,
 171         NLA_U16,
 172         NLA_U32,
 173         NLA_U64,
 174         NLA_STRING,
 175         NLA_FLAG,
 176         NLA_MSECS,
 177         NLA_NESTED,
 178         NLA_NESTED_COMPAT,
 179         NLA_NUL_STRING,
 180         NLA_BINARY,
 181         __NLA_TYPE_MAX,
 182 };
 183
 184 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 185
 186 /**
 187  * struct nla_policy - attribute validation policy
 188  * @type: Type of attribute or NLA_UNSPEC
 189  * @len: Type specific length of payload
 190  *
 191  * Policies are defined as arrays of this struct, the array must be
 192  * accessible by attribute type up to the highest identifier to be expected.
 193  *
 194  * Meaning of `len' field:
 195  *    NLA_STRING           Maximum length of string
 196  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 197  *    NLA_FLAG             Unused
 198  *    NLA_BINARY           Maximum length of attribute payload
 199  *    NLA_NESTED_COMPAT    Exact length of structure payload
 200  *    All other            Exact length of attribute payload
 201  *
 202  * Example:
 203  * static struct nla_policy my_policy[ATTR_MAX+1] __read_mostly = {
 204  *      [ATTR_FOO] = { .type = NLA_U16 },
 205  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 206  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 207  * };
 208  */
 209 struct nla_policy {
 210         u16             type;
 211         u16             len;
 212 };
 213
 214 /**
 215  * struct nl_info - netlink source information
 216  * @nlh: Netlink message header of original request
 217  * @pid: Netlink PID of requesting application
 218  */
 219 struct nl_info {
 220         struct nlmsghdr         *nlh;
 221         struct net              *nl_net;
 222         u32                     pid;
 223 };
 224
 225 extern int              netlink_rcv_skb(struct sk_buff *skb,
 226                                         int (*cb)(struct sk_buff *,
 227                                                   struct nlmsghdr *));
 228 extern int              nlmsg_notify(struct sock *sk, struct sk_buff *skb,
 229                                      u32 pid, unsigned int group, int report,
 230                                      gfp_t flags);
 231
 232 extern int              nla_validate(struct nlattr *head, int len, int maxtype,
 233                                      const struct nla_policy *policy);
 234 extern int              nla_parse(struct nlattr *tb[], int maxtype,
 235                                   struct nlattr *head, int len,
 236                                   const struct nla_policy *policy);
 237 extern struct nlattr *  nla_find(struct nlattr *head, int len, int attrtype);
 238 extern size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
 239                                     size_t dstsize);
 240 extern int              nla_memcpy(void *dest, struct nlattr *src, int count);
 241 extern int              nla_memcmp(const struct nlattr *nla, const void *data,
 242                                    size_t size);
 243 extern int              nla_strcmp(const struct nlattr *nla, const char *str);
 244 extern struct nlattr *  __nla_reserve(struct sk_buff *skb, int attrtype,
 245                                       int attrlen);
 246 extern void *           __nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 247 extern struct nlattr *  nla_reserve(struct sk_buff *skb, int attrtype,
 248                                     int attrlen);
 249 extern void *           nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 250 extern void             __nla_put(struct sk_buff *skb, int attrtype,
 251                                   int attrlen, const void *data);
 252 extern void             __nla_put_nohdr(struct sk_buff *skb, int attrlen,
 253                                         const void *data);
 254 extern int              nla_put(struct sk_buff *skb, int attrtype,
 255                                 int attrlen, const void *data);
 256 extern int              nla_put_nohdr(struct sk_buff *skb, int attrlen,
 257                                       const void *data);
 258 extern int              nla_append(struct sk_buff *skb, int attrlen,
 259                                    const void *data);
 260
 261 /**************************************************************************
 262  * Netlink Messages
 263  **************************************************************************/
 264
 265 /**
 266  * nlmsg_msg_size - length of netlink message not including padding
 267  * @payload: length of message payload
 268  */
 269 static inline int nlmsg_msg_size(int payload)
 270 {
 271         return NLMSG_HDRLEN + payload;
 272 }
 273
 274 /**
 275  * nlmsg_total_size - length of netlink message including padding
 276  * @payload: length of message payload
 277  */
 278 static inline int nlmsg_total_size(int payload)
 279 {
 280         return NLMSG_ALIGN(nlmsg_msg_size(payload));
 281 }
 282
 283 /**
 284  * nlmsg_padlen - length of padding at the message's tail
 285  * @payload: length of message payload
 286  */
 287 static inline int nlmsg_padlen(int payload)
 288 {
 289         return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
 290 }
 291
 292 /**
 293  * nlmsg_data - head of message payload
 294  * @nlh: netlink messsage header
 295  */
 296 static inline void *nlmsg_data(const struct nlmsghdr *nlh)
 297 {
 298         return (unsigned char *) nlh + NLMSG_HDRLEN;
 299 }
 300
 301 /**
 302  * nlmsg_len - length of message payload
 303  * @nlh: netlink message header
 304  */
 305 static inline int nlmsg_len(const struct nlmsghdr *nlh)
 306 {
 307         return nlh->nlmsg_len - NLMSG_HDRLEN;
 308 }
 309
 310 /**
 311  * nlmsg_attrdata - head of attributes data
 312  * @nlh: netlink message header
 313  * @hdrlen: length of family specific header
 314  */
 315 static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
 316                                             int hdrlen)
 317 {
 318         unsigned char *data = nlmsg_data(nlh);
 319         return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
 320 }
 321
 322 /**
 323  * nlmsg_attrlen - length of attributes data
 324  * @nlh: netlink message header
 325  * @hdrlen: length of family specific header
 326  */
 327 static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
 328 {
 329         return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
 330 }
 331
 332 /**
 333  * nlmsg_ok - check if the netlink message fits into the remaining bytes
 334  * @nlh: netlink message header
 335  * @remaining: number of bytes remaining in message stream
 336  */
 337 static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
 338 {
 339         return (remaining >= sizeof(struct nlmsghdr) &&
 340                 nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
 341                 nlh->nlmsg_len <= remaining);
 342 }
 343
 344 /**
 345  * nlmsg_next - next netlink message in message stream
 346  * @nlh: netlink message header
 347  * @remaining: number of bytes remaining in message stream
 348  *
 349  * Returns the next netlink message in the message stream and
 350  * decrements remaining by the size of the current message.
 351  */
 352 static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
 353 {
 354         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 355
 356         *remaining -= totlen;
 357
 358         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 359 }
 360
 361 /**
 362  * nlmsg_parse - parse attributes of a netlink message
 363  * @nlh: netlink message header
 364  * @hdrlen: length of family specific header
 365  * @tb: destination array with maxtype+1 elements
 366  * @maxtype: maximum attribute type to be expected
 367  * @policy: validation policy
 368  *
 369  * See nla_parse()
 370  */
 371 static inline int nlmsg_parse(struct nlmsghdr *nlh, int hdrlen,
 372                               struct nlattr *tb[], int maxtype,
 373                               const struct nla_policy *policy)
 374 {
 375         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 376                 return -EINVAL;
 377
 378         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 379                          nlmsg_attrlen(nlh, hdrlen), policy);
 380 }
 381
 382 /**
 383  * nlmsg_find_attr - find a specific attribute in a netlink message
 384  * @nlh: netlink message header
 385  * @hdrlen: length of familiy specific header
 386  * @attrtype: type of attribute to look for
 387  *
 388  * Returns the first attribute which matches the specified type.
 389  */
 390 static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh,
 391                                              int hdrlen, int attrtype)
 392 {
 393         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 394                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 395 }
 396
 397 /**
 398  * nlmsg_validate - validate a netlink message including attributes
 399  * @nlh: netlinket message header
 400  * @hdrlen: length of familiy specific header
 401  * @maxtype: maximum attribute type to be expected
 402  * @policy: validation policy
 403  */
 404 static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
 405                                  const struct nla_policy *policy)
 406 {
 407         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 408                 return -EINVAL;
 409
 410         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 411                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 412 }
 413
 414 /**
 415  * nlmsg_report - need to report back to application?
 416  * @nlh: netlink message header
 417  *
 418  * Returns 1 if a report back to the application is requested.
 419  */
 420 static inline int nlmsg_report(struct nlmsghdr *nlh)
 421 {
 422         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 423 }
 424
 425 /**
 426  * nlmsg_for_each_attr - iterate over a stream of attributes
 427  * @pos: loop counter, set to current attribute
 428  * @nlh: netlink message header
 429  * @hdrlen: length of familiy specific header
 430  * @rem: initialized to len, holds bytes currently remaining in stream
 431  */
 432 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 433         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 434                           nlmsg_attrlen(nlh, hdrlen), rem)
 435
 436 #if 0
 437 /* FIXME: Enable once all users have been converted */
 438
 439 /**
 440  * __nlmsg_put - Add a new netlink message to an skb
 441  * @skb: socket buffer to store message in
 442  * @pid: netlink process id
 443  * @seq: sequence number of message
 444  * @type: message type
 445  * @payload: length of message payload
 446  * @flags: message flags
 447  *
 448  * The caller is responsible to ensure that the skb provides enough
 449  * tailroom for both the netlink header and payload.
 450  */
 451 static inline struct nlmsghdr *__nlmsg_put(struct sk_buff *skb, u32 pid,
 452                                            u32 seq, int type, int payload,
 453                                            int flags)
 454 {
 455         struct nlmsghdr *nlh;
 456
 457         nlh = (struct nlmsghdr *) skb_put(skb, nlmsg_total_size(payload));
 458         nlh->nlmsg_type = type;
 459         nlh->nlmsg_len = nlmsg_msg_size(payload);
 460         nlh->nlmsg_flags = flags;
 461         nlh->nlmsg_pid = pid;
 462         nlh->nlmsg_seq = seq;
 463
 464         memset((unsigned char *) nlmsg_data(nlh) + payload, 0,
 465                nlmsg_padlen(payload));
 466
 467         return nlh;
 468 }
 469 #endif
 470
 471 /**
 472  * nlmsg_put - Add a new netlink message to an skb
 473  * @skb: socket buffer to store message in
 474  * @pid: netlink process id
 475  * @seq: sequence number of message
 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(struct sk_buff *skb, u32 pid, u32 seq,
 484                                          int type, int payload, int flags)
 485 {
 486         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 487                 return NULL;
 488
 489         return __nlmsg_put(skb, pid, seq, type, payload, flags);
 490 }
 491
 492 /**
 493  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 494  * @skb: socket buffer to store message in
 495  * @cb: netlink callback
 496  * @type: message type
 497  * @payload: length of message payload
 498  * @flags: message flags
 499  *
 500  * Returns NULL if the tailroom of the skb is insufficient to store
 501  * the message header and payload.
 502  */
 503 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 504                                                 struct netlink_callback *cb,
 505                                                 int type, int payload,
 506                                                 int flags)
 507 {
 508         return nlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
 509                          type, payload, flags);
 510 }
 511
 512 /**
 513  * nlmsg_new - Allocate a new netlink message
 514  * @payload: size of the message payload
 515  * @flags: the type of memory to allocate.
 516  *
 517  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 518  * and a good default is needed.
 519  */
 520 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 521 {
 522         return alloc_skb(nlmsg_total_size(payload), flags);
 523 }
 524
 525 /**
 526  * nlmsg_end - Finalize a netlink message
 527  * @skb: socket buffer the message is stored in
 528  * @nlh: netlink message header
 529  *
 530  * Corrects the netlink message header to include the appeneded
 531  * attributes. Only necessary if attributes have been added to
 532  * the message.
 533  *
 534  * Returns the total data length of the skb.
 535  */
 536 static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 537 {
 538         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 539
 540         return skb->len;
 541 }
 542
 543 /**
 544  * nlmsg_get_pos - return current position in netlink message
 545  * @skb: socket buffer the message is stored in
 546  *
 547  * Returns a pointer to the current tail of the message.
 548  */
 549 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 550 {
 551         return skb_tail_pointer(skb);
 552 }
 553
 554 /**
 555  * nlmsg_trim - Trim message to a mark
 556  * @skb: socket buffer the message is stored in
 557  * @mark: mark to trim to
 558  *
 559  * Trims the message to the provided mark.
 560  */
 561 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 562 {
 563         if (mark)
 564                 skb_trim(skb, (unsigned char *) mark - skb->data);
 565 }
 566
 567 /**
 568  * nlmsg_cancel - Cancel construction of a netlink message
 569  * @skb: socket buffer the message is stored in
 570  * @nlh: netlink message header
 571  *
 572  * Removes the complete netlink message including all
 573  * attributes from the socket buffer again.
 574  */
 575 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 576 {
 577         nlmsg_trim(skb, nlh);
 578 }
 579
 580 /**
 581  * nlmsg_free - free a netlink message
 582  * @skb: socket buffer of netlink message
 583  */
 584 static inline void nlmsg_free(struct sk_buff *skb)
 585 {
 586         kfree_skb(skb);
 587 }
 588
 589 /**
 590  * nlmsg_multicast - multicast a netlink message
 591  * @sk: netlink socket to spread messages to
 592  * @skb: netlink message as socket buffer
 593  * @pid: own netlink pid to avoid sending to yourself
 594  * @group: multicast group id
 595  * @flags: allocation flags
 596  */
 597 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 598                                   u32 pid, unsigned int group, gfp_t flags)
 599 {
 600         int err;
 601
 602         NETLINK_CB(skb).dst_group = group;
 603
 604         err = netlink_broadcast(sk, skb, pid, group, flags);
 605         if (err > 0)
 606                 err = 0;
 607
 608         return err;
 609 }
 610
 611 /**
 612  * nlmsg_unicast - unicast a netlink message
 613  * @sk: netlink socket to spread message to
 614  * @skb: netlink message as socket buffer
 615  * @pid: netlink pid of the destination socket
 616  */
 617 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
 618 {
 619         int err;
 620
 621         err = netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
 622         if (err > 0)
 623                 err = 0;
 624
 625         return err;
 626 }
 627
 628 /**
 629  * nlmsg_for_each_msg - iterate over a stream of messages
 630  * @pos: loop counter, set to current message
 631  * @head: head of message stream
 632  * @len: length of message stream
 633  * @rem: initialized to len, holds bytes currently remaining in stream
 634  */
 635 #define nlmsg_for_each_msg(pos, head, len, rem) \
 636         for (pos = head, rem = len; \
 637              nlmsg_ok(pos, rem); \
 638              pos = nlmsg_next(pos, &(rem)))
 639
 640 /**************************************************************************
 641  * Netlink Attributes
 642  **************************************************************************/
 643
 644 /**
 645  * nla_attr_size - length of attribute not including padding
 646  * @payload: length of payload
 647  */
 648 static inline int nla_attr_size(int payload)
 649 {
 650         return NLA_HDRLEN + payload;
 651 }
 652
 653 /**
 654  * nla_total_size - total length of attribute including padding
 655  * @payload: length of payload
 656  */
 657 static inline int nla_total_size(int payload)
 658 {
 659         return NLA_ALIGN(nla_attr_size(payload));
 660 }
 661
 662 /**
 663  * nla_padlen - length of padding at the tail of attribute
 664  * @payload: length of payload
 665  */
 666 static inline int nla_padlen(int payload)
 667 {
 668         return nla_total_size(payload) - nla_attr_size(payload);
 669 }
 670
 671 /**
 672  * nla_type - attribute type
 673  * @nla: netlink attribute
 674  */
 675 static inline int nla_type(const struct nlattr *nla)
 676 {
 677         return nla->nla_type & NLA_TYPE_MASK;
 678 }
 679
 680 /**
 681  * nla_data - head of payload
 682  * @nla: netlink attribute
 683  */
 684 static inline void *nla_data(const struct nlattr *nla)
 685 {
 686         return (char *) nla + NLA_HDRLEN;
 687 }
 688
 689 /**
 690  * nla_len - length of payload
 691  * @nla: netlink attribute
 692  */
 693 static inline int nla_len(const struct nlattr *nla)
 694 {
 695         return nla->nla_len - NLA_HDRLEN;
 696 }
 697
 698 /**
 699  * nla_ok - check if the netlink attribute fits into the remaining bytes
 700  * @nla: netlink attribute
 701  * @remaining: number of bytes remaining in attribute stream
 702  */
 703 static inline int nla_ok(const struct nlattr *nla, int remaining)
 704 {
 705         return remaining >= sizeof(*nla) &&
 706                nla->nla_len >= sizeof(*nla) &&
 707                nla->nla_len <= remaining;
 708 }
 709
 710 /**
 711  * nla_next - next netlink attribute in attribute stream
 712  * @nla: netlink attribute
 713  * @remaining: number of bytes remaining in attribute stream
 714  *
 715  * Returns the next netlink attribute in the attribute stream and
 716  * decrements remaining by the size of the current attribute.
 717  */
 718 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 719 {
 720         int totlen = NLA_ALIGN(nla->nla_len);
 721
 722         *remaining -= totlen;
 723         return (struct nlattr *) ((char *) nla + totlen);
 724 }
 725
 726 /**
 727  * nla_find_nested - find attribute in a set of nested attributes
 728  * @nla: attribute containing the nested attributes
 729  * @attrtype: type of attribute to look for
 730  *
 731  * Returns the first attribute which matches the specified type.
 732  */
 733 static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)
 734 {
 735         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 736 }
 737
 738 /**
 739  * nla_parse_nested - parse nested attributes
 740  * @tb: destination array with maxtype+1 elements
 741  * @maxtype: maximum attribute type to be expected
 742  * @nla: attribute containing the nested attributes
 743  * @policy: validation policy
 744  *
 745  * See nla_parse()
 746  */
 747 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 748                                    struct nlattr *nla,
 749                                    const struct nla_policy *policy)
 750 {
 751         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 752 }
 753
 754 /**
 755  * nla_parse_nested_compat - parse nested compat attributes
 756  * @tb: destination array with maxtype+1 elements
 757  * @maxtype: maximum attribute type to be expected
 758  * @nla: attribute containing the nested attributes
 759  * @data: pointer to point to contained structure
 760  * @len: length of contained structure
 761  * @policy: validation policy
 762  *
 763  * Parse a nested compat attribute. The compat attribute contains a structure
 764  * and optionally a set of nested attributes. On success the data pointer
 765  * points to the nested data and tb contains the parsed attributes
 766  * (see nla_parse).
 767  */
 768 static inline int __nla_parse_nested_compat(struct nlattr *tb[], int maxtype,
 769                                             struct nlattr *nla,
 770                                             const struct nla_policy *policy,
 771                                             int len)
 772 {
 773         int nested_len = nla_len(nla) - NLA_ALIGN(len);
 774
 775         if (nested_len < 0)
 776                 return -EINVAL;
 777         if (nested_len >= nla_attr_size(0))
 778                 return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
 779                                  nested_len, policy);
 780         memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
 781         return 0;
 782 }
 783
 784 #define nla_parse_nested_compat(tb, maxtype, nla, policy, data, len) \
 785 ({      data = nla_len(nla) >= len ? nla_data(nla) : NULL; \
 786         __nla_parse_nested_compat(tb, maxtype, nla, policy, len); })
 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_U32(skb, attrtype, value) \
 891         NLA_PUT_TYPE(skb, u32, attrtype, value)
 892
 893 #define NLA_PUT_BE32(skb, attrtype, value) \
 894         NLA_PUT_TYPE(skb, __be32, attrtype, value)
 895
 896 #define NLA_PUT_U64(skb, attrtype, value) \
 897         NLA_PUT_TYPE(skb, u64, attrtype, value)
 898
 899 #define NLA_PUT_STRING(skb, attrtype, value) \
 900         NLA_PUT(skb, attrtype, strlen(value) + 1, value)
 901
 902 #define NLA_PUT_FLAG(skb, attrtype) \
 903         NLA_PUT(skb, attrtype, 0, NULL)
 904
 905 #define NLA_PUT_MSECS(skb, attrtype, jiffies) \
 906         NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))
 907
 908 /**
 909  * nla_get_u32 - return payload of u32 attribute
 910  * @nla: u32 netlink attribute
 911  */
 912 static inline u32 nla_get_u32(struct nlattr *nla)
 913 {
 914         return *(u32 *) nla_data(nla);
 915 }
 916
 917 /**
 918  * nla_get_be32 - return payload of __be32 attribute
 919  * @nla: __be32 netlink attribute
 920  */
 921 static inline __be32 nla_get_be32(struct nlattr *nla)
 922 {
 923         return *(__be32 *) nla_data(nla);
 924 }
 925
 926 /**
 927  * nla_get_u16 - return payload of u16 attribute
 928  * @nla: u16 netlink attribute
 929  */
 930 static inline u16 nla_get_u16(struct nlattr *nla)
 931 {
 932         return *(u16 *) nla_data(nla);
 933 }
 934
 935 /**
 936  * nla_get_be16 - return payload of __be16 attribute
 937  * @nla: __be16 netlink attribute
 938  */
 939 static inline __be16 nla_get_be16(struct nlattr *nla)
 940 {
 941         return *(__be16 *) nla_data(nla);
 942 }
 943
 944 /**
 945  * nla_get_le16 - return payload of __le16 attribute
 946  * @nla: __le16 netlink attribute
 947  */
 948 static inline __le16 nla_get_le16(struct nlattr *nla)
 949 {
 950         return *(__le16 *) nla_data(nla);
 951 }
 952
 953 /**
 954  * nla_get_u8 - return payload of u8 attribute
 955  * @nla: u8 netlink attribute
 956  */
 957 static inline u8 nla_get_u8(struct nlattr *nla)
 958 {
 959         return *(u8 *) nla_data(nla);
 960 }
 961
 962 /**
 963  * nla_get_u64 - return payload of u64 attribute
 964  * @nla: u64 netlink attribute
 965  */
 966 static inline u64 nla_get_u64(struct nlattr *nla)
 967 {
 968         u64 tmp;
 969
 970         nla_memcpy(&tmp, nla, sizeof(tmp));
 971
 972         return tmp;
 973 }
 974
 975 /**
 976  * nla_get_flag - return payload of flag attribute
 977  * @nla: flag netlink attribute
 978  */
 979 static inline int nla_get_flag(struct nlattr *nla)
 980 {
 981         return !!nla;
 982 }
 983
 984 /**
 985  * nla_get_msecs - return payload of msecs attribute
 986  * @nla: msecs netlink attribute
 987  *
 988  * Returns the number of milliseconds in jiffies.
 989  */
 990 static inline unsigned long nla_get_msecs(struct nlattr *nla)
 991 {
 992         u64 msecs = nla_get_u64(nla);
 993
 994         return msecs_to_jiffies((unsigned long) msecs);
 995 }
 996
 997 /**
 998  * nla_nest_start - Start a new level of nested attributes
 999  * @skb: socket buffer to add attributes to
1000  * @attrtype: attribute type of container
1001  *
1002  * Returns the container attribute
1003  */
1004 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1005 {
1006         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1007
1008         if (nla_put(skb, attrtype, 0, NULL) < 0)
1009                 return NULL;
1010
1011         return start;
1012 }
1013
1014 /**
1015  * nla_nest_end - Finalize nesting of attributes
1016  * @skb: socket buffer the attributes are stored in
1017  * @start: container attribute
1018  *
1019  * Corrects the container attribute header to include the all
1020  * appeneded attributes.
1021  *
1022  * Returns the total data length of the skb.
1023  */
1024 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1025 {
1026         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1027         return skb->len;
1028 }
1029
1030 /**
1031  * nla_nest_compat_start - Start a new level of nested compat attributes
1032  * @skb: socket buffer to add attributes to
1033  * @attrtype: attribute type of container
1034  * @attrlen: length of structure
1035  * @data: pointer to structure
1036  *
1037  * Start a nested compat attribute that contains both a structure and
1038  * a set of nested attributes.
1039  *
1040  * Returns the container attribute
1041  */
1042 static inline struct nlattr *nla_nest_compat_start(struct sk_buff *skb,
1043                                                    int attrtype, int attrlen,
1044                                                    const void *data)
1045 {
1046         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1047
1048         if (nla_put(skb, attrtype, attrlen, data) < 0)
1049                 return NULL;
1050         if (nla_nest_start(skb, attrtype) == NULL) {
1051                 nlmsg_trim(skb, start);
1052                 return NULL;
1053         }
1054         return start;
1055 }
1056
1057 /**
1058  * nla_nest_compat_end - Finalize nesting of compat attributes
1059  * @skb: socket buffer the attributes are stored in
1060  * @start: container attribute
1061  *
1062  * Corrects the container attribute header to include the all
1063  * appeneded attributes.
1064  *
1065  * Returns the total data length of the skb.
1066  */
1067 static inline int nla_nest_compat_end(struct sk_buff *skb, struct nlattr *start)
1068 {
1069         struct nlattr *nest = (void *)start + NLMSG_ALIGN(start->nla_len);
1070
1071         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1072         return nla_nest_end(skb, nest);
1073 }
1074
1075 /**
1076  * nla_nest_cancel - Cancel nesting of attributes
1077  * @skb: socket buffer the message is stored in
1078  * @start: container attribute
1079  *
1080  * Removes the container attribute and including all nested
1081  * attributes. Returns -EMSGSIZE
1082  */
1083 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1084 {
1085         nlmsg_trim(skb, start);
1086 }
1087
1088 /**
1089  * nla_validate_nested - Validate a stream of nested attributes
1090  * @start: container attribute
1091  * @maxtype: maximum attribute type to be expected
1092  * @policy: validation policy
1093  *
1094  * Validates all attributes in the nested attribute stream against the
1095  * specified policy. Attributes with a type exceeding maxtype will be
1096  * ignored. See documenation of struct nla_policy for more details.
1097  *
1098  * Returns 0 on success or a negative error code.
1099  */
1100 static inline int nla_validate_nested(struct nlattr *start, int maxtype,
1101                                       const struct nla_policy *policy)
1102 {
1103         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1104 }
1105
1106 /**
1107  * nla_for_each_attr - iterate over a stream of attributes
1108  * @pos: loop counter, set to current attribute
1109  * @head: head of attribute stream
1110  * @len: length of attribute stream
1111  * @rem: initialized to len, holds bytes currently remaining in stream
1112  */
1113 #define nla_for_each_attr(pos, head, len, rem) \
1114         for (pos = head, rem = len; \
1115              nla_ok(pos, rem); \
1116              pos = nla_next(pos, &(rem)))
1117
1118 /**
1119  * nla_for_each_nested - iterate over nested attributes
1120  * @pos: loop counter, set to current attribute
1121  * @nla: attribute containing the nested attributes
1122  * @rem: initialized to len, holds bytes currently remaining in stream
1123  */
1124 #define nla_for_each_nested(pos, nla, rem) \
1125         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1126
1127 #endif