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 #include <linux/in6.h>
   8
   9 /* ========================================================================
  10  *         Netlink Messages and Attributes Interface (As Seen On TV)
  11  * ------------------------------------------------------------------------
  12  *                          Messages Interface
  13  * ------------------------------------------------------------------------
  14  *
  15  * Message Format:
  16  *    <--- nlmsg_total_size(payload)  --->
  17  *    <-- nlmsg_msg_size(payload) ->
  18  *   +----------+- - -+-------------+- - -+-------- - -
  19  *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
  20  *   +----------+- - -+-------------+- - -+-------- - -
  21  *   nlmsg_data(nlh)---^                   ^
  22  *   nlmsg_next(nlh)-----------------------+
  23  *
  24  * Payload Format:
  25  *    <---------------------- nlmsg_len(nlh) --------------------->
  26  *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
  27  *   +----------------------+- - -+--------------------------------+
  28  *   |     Family Header    | Pad |           Attributes           |
  29  *   +----------------------+- - -+--------------------------------+
  30  *   nlmsg_attrdata(nlh, hdrlen)---^
  31  *
  32  * Data Structures:
  33  *   struct nlmsghdr                    netlink message header
  34  *
  35  * Message Construction:
  36  *   nlmsg_new()                        create a new netlink message
  37  *   nlmsg_put()                        add a netlink message to an skb
  38  *   nlmsg_put_answer()                 callback based nlmsg_put()
  39  *   nlmsg_end()                        finalize netlink message
  40  *   nlmsg_get_pos()                    return current position in message
  41  *   nlmsg_trim()                       trim part of message
  42  *   nlmsg_cancel()                     cancel message construction
  43  *   nlmsg_free()                       free a netlink message
  44  *
  45  * Message Sending:
  46  *   nlmsg_multicast()                  multicast message to several groups
  47  *   nlmsg_unicast()                    unicast a message to a single socket
  48  *   nlmsg_notify()                     send notification message
  49  *
  50  * Message Length Calculations:
  51  *   nlmsg_msg_size(payload)            length of message w/o padding
  52  *   nlmsg_total_size(payload)          length of message w/ padding
  53  *   nlmsg_padlen(payload)              length of padding at tail
  54  *
  55  * Message Payload Access:
  56  *   nlmsg_data(nlh)                    head of message payload
  57  *   nlmsg_len(nlh)                     length of message payload
  58  *   nlmsg_attrdata(nlh, hdrlen)        head of attributes data
  59  *   nlmsg_attrlen(nlh, hdrlen)         length of attributes data
  60  *
  61  * Message Parsing:
  62  *   nlmsg_ok(nlh, remaining)           does nlh fit into remaining bytes?
  63  *   nlmsg_next(nlh, remaining)         get next netlink message
  64  *   nlmsg_parse()                      parse attributes of a message
  65  *   nlmsg_find_attr()                  find an attribute in a message
  66  *   nlmsg_for_each_msg()               loop over all messages
  67  *   nlmsg_validate()                   validate netlink message incl. attrs
  68  *   nlmsg_for_each_attr()              loop over all attributes
  69  *
  70  * Misc:
  71  *   nlmsg_report()                     report back to application?
  72  *
  73  * ------------------------------------------------------------------------
  74  *                          Attributes Interface
  75  * ------------------------------------------------------------------------
  76  *
  77  * Attribute Format:
  78  *    <------- nla_total_size(payload) ------->
  79  *    <---- nla_attr_size(payload) ----->
  80  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  81  *   |  Header  | Pad |     Payload      | Pad |  Header
  82  *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
  83  *                     <- nla_len(nla) ->      ^
  84  *   nla_data(nla)----^                        |
  85  *   nla_next(nla)-----------------------------'
  86  *
  87  * Data Structures:
  88  *   struct nlattr                      netlink attribute header
  89  *
  90  * Attribute Construction:
  91  *   nla_reserve(skb, type, len)        reserve room for an attribute
  92  *   nla_reserve_nohdr(skb, len)        reserve room for an attribute w/o hdr
  93  *   nla_put(skb, type, len, data)      add attribute to skb
  94  *   nla_put_nohdr(skb, len, data)      add attribute w/o hdr
  95  *   nla_append(skb, len, data)         append data to skb
  96  *
  97  * Attribute Construction for Basic Types:
  98  *   nla_put_u8(skb, type, value)       add u8 attribute to skb
  99  *   nla_put_u16(skb, type, value)      add u16 attribute to skb
 100  *   nla_put_u32(skb, type, value)      add u32 attribute to skb
 101  *   nla_put_u64(skb, type, value)      add u64 attribute to skb
 102  *   nla_put_s8(skb, type, value)       add s8 attribute to skb
 103  *   nla_put_s16(skb, type, value)      add s16 attribute to skb
 104  *   nla_put_s32(skb, type, value)      add s32 attribute to skb
 105  *   nla_put_s64(skb, type, value)      add s64 attribute to skb
 106  *   nla_put_string(skb, type, str)     add string attribute to skb
 107  *   nla_put_flag(skb, type)            add flag attribute to skb
 108  *   nla_put_msecs(skb, type, jiffies)  add msecs attribute to skb
 109  *   nla_put_in_addr(skb, type, addr)   add IPv4 address attribute to skb
 110  *   nla_put_in6_addr(skb, type, addr)  add IPv6 address attribute to skb
 111  *
 112  * Nested Attributes Construction:
 113  *   nla_nest_start(skb, type)          start a nested attribute
 114  *   nla_nest_end(skb, nla)             finalize a nested attribute
 115  *   nla_nest_cancel(skb, nla)          cancel nested attribute construction
 116  *
 117  * Attribute Length Calculations:
 118  *   nla_attr_size(payload)             length of attribute w/o padding
 119  *   nla_total_size(payload)            length of attribute w/ padding
 120  *   nla_padlen(payload)                length of padding
 121  *
 122  * Attribute Payload Access:
 123  *   nla_data(nla)                      head of attribute payload
 124  *   nla_len(nla)                       length of attribute payload
 125  *
 126  * Attribute Payload Access for Basic Types:
 127  *   nla_get_u8(nla)                    get payload for a u8 attribute
 128  *   nla_get_u16(nla)                   get payload for a u16 attribute
 129  *   nla_get_u32(nla)                   get payload for a u32 attribute
 130  *   nla_get_u64(nla)                   get payload for a u64 attribute
 131  *   nla_get_s8(nla)                    get payload for a s8 attribute
 132  *   nla_get_s16(nla)                   get payload for a s16 attribute
 133  *   nla_get_s32(nla)                   get payload for a s32 attribute
 134  *   nla_get_s64(nla)                   get payload for a s64 attribute
 135  *   nla_get_flag(nla)                  return 1 if flag is true
 136  *   nla_get_msecs(nla)                 get payload for a msecs attribute
 137  *
 138  * Attribute Misc:
 139  *   nla_memcpy(dest, nla, count)       copy attribute into memory
 140  *   nla_memcmp(nla, data, size)        compare attribute with memory area
 141  *   nla_strlcpy(dst, nla, size)        copy attribute to a sized string
 142  *   nla_strcmp(nla, str)               compare attribute with string
 143  *
 144  * Attribute Parsing:
 145  *   nla_ok(nla, remaining)             does nla fit into remaining bytes?
 146  *   nla_next(nla, remaining)           get next netlink attribute
 147  *   nla_validate()                     validate a stream of attributes
 148  *   nla_validate_nested()              validate a stream of nested attributes
 149  *   nla_find()                         find attribute in stream of attributes
 150  *   nla_find_nested()                  find attribute in nested attributes
 151  *   nla_parse()                        parse and validate stream of attrs
 152  *   nla_parse_nested()                 parse nested attribuets
 153  *   nla_for_each_attr()                loop over all attributes
 154  *   nla_for_each_nested()              loop over the nested attributes
 155  *=========================================================================
 156  */
 157
 158  /**
 159   * Standard attribute types to specify validation policy
 160   */
 161 enum {
 162         NLA_UNSPEC,
 163         NLA_U8,
 164         NLA_U16,
 165         NLA_U32,
 166         NLA_U64,
 167         NLA_STRING,
 168         NLA_FLAG,
 169         NLA_MSECS,
 170         NLA_NESTED,
 171         NLA_NESTED_COMPAT,
 172         NLA_NUL_STRING,
 173         NLA_BINARY,
 174         NLA_S8,
 175         NLA_S16,
 176         NLA_S32,
 177         NLA_S64,
 178         __NLA_TYPE_MAX,
 179 };
 180
 181 #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
 182
 183 /**
 184  * struct nla_policy - attribute validation policy
 185  * @type: Type of attribute or NLA_UNSPEC
 186  * @len: Type specific length of payload
 187  *
 188  * Policies are defined as arrays of this struct, the array must be
 189  * accessible by attribute type up to the highest identifier to be expected.
 190  *
 191  * Meaning of `len' field:
 192  *    NLA_STRING           Maximum length of string
 193  *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 194  *    NLA_FLAG             Unused
 195  *    NLA_BINARY           Maximum length of attribute payload
 196  *    NLA_NESTED           Don't use `len' field -- length verification is
 197  *                         done by checking len of nested header (or empty)
 198  *    NLA_NESTED_COMPAT    Minimum length of structure payload
 199  *    NLA_U8, NLA_U16,
 200  *    NLA_U32, NLA_U64,
 201  *    NLA_S8, NLA_S16,
 202  *    NLA_S32, NLA_S64,
 203  *    NLA_MSECS            Leaving the length field zero will verify the
 204  *                         given type fits, using it verifies minimum length
 205  *                         just like "All other"
 206  *    All other            Minimum length of attribute payload
 207  *
 208  * Example:
 209  * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 210  *      [ATTR_FOO] = { .type = NLA_U16 },
 211  *      [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 212  *      [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
 213  * };
 214  */
 215 struct nla_policy {
 216         u16             type;
 217         u16             len;
 218 };
 219
 220 /**
 221  * struct nl_info - netlink source information
 222  * @nlh: Netlink message header of original request
 223  * @portid: Netlink PORTID of requesting application
 224  */
 225 struct nl_info {
 226         struct nlmsghdr         *nlh;
 227         struct net              *nl_net;
 228         u32                     portid;
 229 };
 230
 231 int netlink_rcv_skb(struct sk_buff *skb,
 232                     int (*cb)(struct sk_buff *, struct nlmsghdr *));
 233 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
 234                  unsigned int group, int report, gfp_t flags);
 235
 236 int nla_validate(const struct nlattr *head, int len, int maxtype,
 237                  const struct nla_policy *policy);
 238 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 239               int len, const struct nla_policy *policy);
 240 int nla_policy_len(const struct nla_policy *, int);
 241 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 242 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
 243 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 244 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 245 int nla_strcmp(const struct nlattr *nla, const char *str);
 246 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 247 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 248 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
 249 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
 250 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 251                const void *data);
 252 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 253 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
 254 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
 255 int nla_append(struct sk_buff *skb, int attrlen, 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 message 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 >= (int) 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 *
 349 nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
 350 {
 351         int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
 352
 353         *remaining -= totlen;
 354
 355         return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
 356 }
 357
 358 /**
 359  * nlmsg_parse - parse attributes of a netlink message
 360  * @nlh: netlink message header
 361  * @hdrlen: length of family specific header
 362  * @tb: destination array with maxtype+1 elements
 363  * @maxtype: maximum attribute type to be expected
 364  * @policy: validation policy
 365  *
 366  * See nla_parse()
 367  */
 368 static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
 369                               struct nlattr *tb[], int maxtype,
 370                               const struct nla_policy *policy)
 371 {
 372         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 373                 return -EINVAL;
 374
 375         return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
 376                          nlmsg_attrlen(nlh, hdrlen), policy);
 377 }
 378
 379 /**
 380  * nlmsg_find_attr - find a specific attribute in a netlink message
 381  * @nlh: netlink message header
 382  * @hdrlen: length of familiy specific header
 383  * @attrtype: type of attribute to look for
 384  *
 385  * Returns the first attribute which matches the specified type.
 386  */
 387 static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
 388                                              int hdrlen, int attrtype)
 389 {
 390         return nla_find(nlmsg_attrdata(nlh, hdrlen),
 391                         nlmsg_attrlen(nlh, hdrlen), attrtype);
 392 }
 393
 394 /**
 395  * nlmsg_validate - validate a netlink message including attributes
 396  * @nlh: netlinket message header
 397  * @hdrlen: length of familiy specific header
 398  * @maxtype: maximum attribute type to be expected
 399  * @policy: validation policy
 400  */
 401 static inline int nlmsg_validate(const struct nlmsghdr *nlh,
 402                                  int hdrlen, int maxtype,
 403                                  const struct nla_policy *policy)
 404 {
 405         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 406                 return -EINVAL;
 407
 408         return nla_validate(nlmsg_attrdata(nlh, hdrlen),
 409                             nlmsg_attrlen(nlh, hdrlen), maxtype, policy);
 410 }
 411
 412 /**
 413  * nlmsg_report - need to report back to application?
 414  * @nlh: netlink message header
 415  *
 416  * Returns 1 if a report back to the application is requested.
 417  */
 418 static inline int nlmsg_report(const struct nlmsghdr *nlh)
 419 {
 420         return !!(nlh->nlmsg_flags & NLM_F_ECHO);
 421 }
 422
 423 /**
 424  * nlmsg_for_each_attr - iterate over a stream of attributes
 425  * @pos: loop counter, set to current attribute
 426  * @nlh: netlink message header
 427  * @hdrlen: length of familiy specific header
 428  * @rem: initialized to len, holds bytes currently remaining in stream
 429  */
 430 #define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
 431         nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 432                           nlmsg_attrlen(nlh, hdrlen), rem)
 433
 434 /**
 435  * nlmsg_put - Add a new netlink message to an skb
 436  * @skb: socket buffer to store message in
 437  * @portid: netlink PORTID of requesting application
 438  * @seq: sequence number of message
 439  * @type: message type
 440  * @payload: length of message payload
 441  * @flags: message flags
 442  *
 443  * Returns NULL if the tailroom of the skb is insufficient to store
 444  * the message header and payload.
 445  */
 446 static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 447                                          int type, int payload, int flags)
 448 {
 449         if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
 450                 return NULL;
 451
 452         return __nlmsg_put(skb, portid, seq, type, payload, flags);
 453 }
 454
 455 /**
 456  * nlmsg_put_answer - Add a new callback based netlink message to an skb
 457  * @skb: socket buffer to store message in
 458  * @cb: netlink callback
 459  * @type: message type
 460  * @payload: length of message payload
 461  * @flags: message flags
 462  *
 463  * Returns NULL if the tailroom of the skb is insufficient to store
 464  * the message header and payload.
 465  */
 466 static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
 467                                                 struct netlink_callback *cb,
 468                                                 int type, int payload,
 469                                                 int flags)
 470 {
 471         return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
 472                          type, payload, flags);
 473 }
 474
 475 /**
 476  * nlmsg_new - Allocate a new netlink message
 477  * @payload: size of the message payload
 478  * @flags: the type of memory to allocate.
 479  *
 480  * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 481  * and a good default is needed.
 482  */
 483 static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
 484 {
 485         return alloc_skb(nlmsg_total_size(payload), flags);
 486 }
 487
 488 /**
 489  * nlmsg_end - Finalize a netlink message
 490  * @skb: socket buffer the message is stored in
 491  * @nlh: netlink message header
 492  *
 493  * Corrects the netlink message header to include the appeneded
 494  * attributes. Only necessary if attributes have been added to
 495  * the message.
 496  */
 497 static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
 498 {
 499         nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
 500 }
 501
 502 /**
 503  * nlmsg_get_pos - return current position in netlink message
 504  * @skb: socket buffer the message is stored in
 505  *
 506  * Returns a pointer to the current tail of the message.
 507  */
 508 static inline void *nlmsg_get_pos(struct sk_buff *skb)
 509 {
 510         return skb_tail_pointer(skb);
 511 }
 512
 513 /**
 514  * nlmsg_trim - Trim message to a mark
 515  * @skb: socket buffer the message is stored in
 516  * @mark: mark to trim to
 517  *
 518  * Trims the message to the provided mark.
 519  */
 520 static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
 521 {
 522         if (mark) {
 523                 WARN_ON((unsigned char *) mark < skb->data);
 524                 skb_trim(skb, (unsigned char *) mark - skb->data);
 525         }
 526 }
 527
 528 /**
 529  * nlmsg_cancel - Cancel construction of a netlink message
 530  * @skb: socket buffer the message is stored in
 531  * @nlh: netlink message header
 532  *
 533  * Removes the complete netlink message including all
 534  * attributes from the socket buffer again.
 535  */
 536 static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
 537 {
 538         nlmsg_trim(skb, nlh);
 539 }
 540
 541 /**
 542  * nlmsg_free - free a netlink message
 543  * @skb: socket buffer of netlink message
 544  */
 545 static inline void nlmsg_free(struct sk_buff *skb)
 546 {
 547         kfree_skb(skb);
 548 }
 549
 550 /**
 551  * nlmsg_multicast - multicast a netlink message
 552  * @sk: netlink socket to spread messages to
 553  * @skb: netlink message as socket buffer
 554  * @portid: own netlink portid to avoid sending to yourself
 555  * @group: multicast group id
 556  * @flags: allocation flags
 557  */
 558 static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
 559                                   u32 portid, unsigned int group, gfp_t flags)
 560 {
 561         int err;
 562
 563         NETLINK_CB(skb).dst_group = group;
 564
 565         err = netlink_broadcast(sk, skb, portid, group, flags);
 566         if (err > 0)
 567                 err = 0;
 568
 569         return err;
 570 }
 571
 572 /**
 573  * nlmsg_unicast - unicast a netlink message
 574  * @sk: netlink socket to spread message to
 575  * @skb: netlink message as socket buffer
 576  * @portid: netlink portid of the destination socket
 577  */
 578 static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
 579 {
 580         int err;
 581
 582         err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
 583         if (err > 0)
 584                 err = 0;
 585
 586         return err;
 587 }
 588
 589 /**
 590  * nlmsg_for_each_msg - iterate over a stream of messages
 591  * @pos: loop counter, set to current message
 592  * @head: head of message stream
 593  * @len: length of message stream
 594  * @rem: initialized to len, holds bytes currently remaining in stream
 595  */
 596 #define nlmsg_for_each_msg(pos, head, len, rem) \
 597         for (pos = head, rem = len; \
 598              nlmsg_ok(pos, rem); \
 599              pos = nlmsg_next(pos, &(rem)))
 600
 601 /**
 602  * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 603  * @cb: netlink callback structure that stores the sequence number
 604  * @nlh: netlink message header to write the flag to
 605  *
 606  * This function checks if the sequence (generation) number changed during dump
 607  * and if it did, advertises it in the netlink message header.
 608  *
 609  * The correct way to use it is to set cb->seq to the generation counter when
 610  * all locks for dumping have been acquired, and then call this function for
 611  * each message that is generated.
 612  *
 613  * Note that due to initialisation concerns, 0 is an invalid sequence number
 614  * and must not be used by code that uses this functionality.
 615  */
 616 static inline void
 617 nl_dump_check_consistent(struct netlink_callback *cb,
 618                          struct nlmsghdr *nlh)
 619 {
 620         if (cb->prev_seq && cb->seq != cb->prev_seq)
 621                 nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
 622         cb->prev_seq = cb->seq;
 623 }
 624
 625 /**************************************************************************
 626  * Netlink Attributes
 627  **************************************************************************/
 628
 629 /**
 630  * nla_attr_size - length of attribute not including padding
 631  * @payload: length of payload
 632  */
 633 static inline int nla_attr_size(int payload)
 634 {
 635         return NLA_HDRLEN + payload;
 636 }
 637
 638 /**
 639  * nla_total_size - total length of attribute including padding
 640  * @payload: length of payload
 641  */
 642 static inline int nla_total_size(int payload)
 643 {
 644         return NLA_ALIGN(nla_attr_size(payload));
 645 }
 646
 647 /**
 648  * nla_padlen - length of padding at the tail of attribute
 649  * @payload: length of payload
 650  */
 651 static inline int nla_padlen(int payload)
 652 {
 653         return nla_total_size(payload) - nla_attr_size(payload);
 654 }
 655
 656 /**
 657  * nla_type - attribute type
 658  * @nla: netlink attribute
 659  */
 660 static inline int nla_type(const struct nlattr *nla)
 661 {
 662         return nla->nla_type & NLA_TYPE_MASK;
 663 }
 664
 665 /**
 666  * nla_data - head of payload
 667  * @nla: netlink attribute
 668  */
 669 static inline void *nla_data(const struct nlattr *nla)
 670 {
 671         return (char *) nla + NLA_HDRLEN;
 672 }
 673
 674 /**
 675  * nla_len - length of payload
 676  * @nla: netlink attribute
 677  */
 678 static inline int nla_len(const struct nlattr *nla)
 679 {
 680         return nla->nla_len - NLA_HDRLEN;
 681 }
 682
 683 /**
 684  * nla_ok - check if the netlink attribute fits into the remaining bytes
 685  * @nla: netlink attribute
 686  * @remaining: number of bytes remaining in attribute stream
 687  */
 688 static inline int nla_ok(const struct nlattr *nla, int remaining)
 689 {
 690         return remaining >= (int) sizeof(*nla) &&
 691                nla->nla_len >= sizeof(*nla) &&
 692                nla->nla_len <= remaining;
 693 }
 694
 695 /**
 696  * nla_next - next netlink attribute in attribute stream
 697  * @nla: netlink attribute
 698  * @remaining: number of bytes remaining in attribute stream
 699  *
 700  * Returns the next netlink attribute in the attribute stream and
 701  * decrements remaining by the size of the current attribute.
 702  */
 703 static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
 704 {
 705         int totlen = NLA_ALIGN(nla->nla_len);
 706
 707         *remaining -= totlen;
 708         return (struct nlattr *) ((char *) nla + totlen);
 709 }
 710
 711 /**
 712  * nla_find_nested - find attribute in a set of nested attributes
 713  * @nla: attribute containing the nested attributes
 714  * @attrtype: type of attribute to look for
 715  *
 716  * Returns the first attribute which matches the specified type.
 717  */
 718 static inline struct nlattr *
 719 nla_find_nested(const struct nlattr *nla, int attrtype)
 720 {
 721         return nla_find(nla_data(nla), nla_len(nla), attrtype);
 722 }
 723
 724 /**
 725  * nla_parse_nested - parse nested attributes
 726  * @tb: destination array with maxtype+1 elements
 727  * @maxtype: maximum attribute type to be expected
 728  * @nla: attribute containing the nested attributes
 729  * @policy: validation policy
 730  *
 731  * See nla_parse()
 732  */
 733 static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
 734                                    const struct nlattr *nla,
 735                                    const struct nla_policy *policy)
 736 {
 737         return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
 738 }
 739
 740 /**
 741  * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 742  * @skb: socket buffer to add attribute to
 743  * @attrtype: attribute type
 744  * @value: numeric value
 745  */
 746 static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
 747 {
 748         return nla_put(skb, attrtype, sizeof(u8), &value);
 749 }
 750
 751 /**
 752  * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 753  * @skb: socket buffer to add attribute to
 754  * @attrtype: attribute type
 755  * @value: numeric value
 756  */
 757 static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
 758 {
 759         return nla_put(skb, attrtype, sizeof(u16), &value);
 760 }
 761
 762 /**
 763  * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 764  * @skb: socket buffer to add attribute to
 765  * @attrtype: attribute type
 766  * @value: numeric value
 767  */
 768 static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
 769 {
 770         return nla_put(skb, attrtype, sizeof(__be16), &value);
 771 }
 772
 773 /**
 774  * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 775  * @skb: socket buffer to add attribute to
 776  * @attrtype: attribute type
 777  * @value: numeric value
 778  */
 779 static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
 780 {
 781         return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 782 }
 783
 784 /**
 785  * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 786  * @skb: socket buffer to add attribute to
 787  * @attrtype: attribute type
 788  * @value: numeric value
 789  */
 790 static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
 791 {
 792         return nla_put(skb, attrtype, sizeof(__le16), &value);
 793 }
 794
 795 /**
 796  * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 797  * @skb: socket buffer to add attribute to
 798  * @attrtype: attribute type
 799  * @value: numeric value
 800  */
 801 static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
 802 {
 803         return nla_put(skb, attrtype, sizeof(u32), &value);
 804 }
 805
 806 /**
 807  * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 808  * @skb: socket buffer to add attribute to
 809  * @attrtype: attribute type
 810  * @value: numeric value
 811  */
 812 static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
 813 {
 814         return nla_put(skb, attrtype, sizeof(__be32), &value);
 815 }
 816
 817 /**
 818  * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 819  * @skb: socket buffer to add attribute to
 820  * @attrtype: attribute type
 821  * @value: numeric value
 822  */
 823 static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
 824 {
 825         return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 826 }
 827
 828 /**
 829  * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 830  * @skb: socket buffer to add attribute to
 831  * @attrtype: attribute type
 832  * @value: numeric value
 833  */
 834 static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
 835 {
 836         return nla_put(skb, attrtype, sizeof(__le32), &value);
 837 }
 838
 839 /**
 840  * nla_put_u64 - Add a u64 netlink attribute to a socket buffer
 841  * @skb: socket buffer to add attribute to
 842  * @attrtype: attribute type
 843  * @value: numeric value
 844  */
 845 static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
 846 {
 847         return nla_put(skb, attrtype, sizeof(u64), &value);
 848 }
 849
 850 /**
 851  * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer
 852  * @skb: socket buffer to add attribute to
 853  * @attrtype: attribute type
 854  * @value: numeric value
 855  */
 856 static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value)
 857 {
 858         return nla_put(skb, attrtype, sizeof(__be64), &value);
 859 }
 860
 861 /**
 862  * nla_put_net64 - Add 64-bit network byte order netlink attribute to a socket buffer
 863  * @skb: socket buffer to add attribute to
 864  * @attrtype: attribute type
 865  * @value: numeric value
 866  */
 867 static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value)
 868 {
 869         return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, value);
 870 }
 871
 872 /**
 873  * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer
 874  * @skb: socket buffer to add attribute to
 875  * @attrtype: attribute type
 876  * @value: numeric value
 877  */
 878 static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value)
 879 {
 880         return nla_put(skb, attrtype, sizeof(__le64), &value);
 881 }
 882
 883 /**
 884  * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 885  * @skb: socket buffer to add attribute to
 886  * @attrtype: attribute type
 887  * @value: numeric value
 888  */
 889 static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
 890 {
 891         return nla_put(skb, attrtype, sizeof(s8), &value);
 892 }
 893
 894 /**
 895  * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 896  * @skb: socket buffer to add attribute to
 897  * @attrtype: attribute type
 898  * @value: numeric value
 899  */
 900 static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
 901 {
 902         return nla_put(skb, attrtype, sizeof(s16), &value);
 903 }
 904
 905 /**
 906  * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 907  * @skb: socket buffer to add attribute to
 908  * @attrtype: attribute type
 909  * @value: numeric value
 910  */
 911 static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
 912 {
 913         return nla_put(skb, attrtype, sizeof(s32), &value);
 914 }
 915
 916 /**
 917  * nla_put_s64 - Add a s64 netlink attribute to a socket buffer
 918  * @skb: socket buffer to add attribute to
 919  * @attrtype: attribute type
 920  * @value: numeric value
 921  */
 922 static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value)
 923 {
 924         return nla_put(skb, attrtype, sizeof(s64), &value);
 925 }
 926
 927 /**
 928  * nla_put_string - Add a string netlink attribute to a socket buffer
 929  * @skb: socket buffer to add attribute to
 930  * @attrtype: attribute type
 931  * @str: NUL terminated string
 932  */
 933 static inline int nla_put_string(struct sk_buff *skb, int attrtype,
 934                                  const char *str)
 935 {
 936         return nla_put(skb, attrtype, strlen(str) + 1, str);
 937 }
 938
 939 /**
 940  * nla_put_flag - Add a flag netlink attribute to a socket buffer
 941  * @skb: socket buffer to add attribute to
 942  * @attrtype: attribute type
 943  */
 944 static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
 945 {
 946         return nla_put(skb, attrtype, 0, NULL);
 947 }
 948
 949 /**
 950  * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 951  * @skb: socket buffer to add attribute to
 952  * @attrtype: attribute type
 953  * @njiffies: number of jiffies to convert to msecs
 954  */
 955 static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
 956                                 unsigned long njiffies)
 957 {
 958         u64 tmp = jiffies_to_msecs(njiffies);
 959         return nla_put(skb, attrtype, sizeof(u64), &tmp);
 960 }
 961
 962 /**
 963  * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 964  * buffer
 965  * @skb: socket buffer to add attribute to
 966  * @attrtype: attribute type
 967  * @addr: IPv4 address
 968  */
 969 static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
 970                                   __be32 addr)
 971 {
 972         return nla_put_be32(skb, attrtype, addr);
 973 }
 974
 975 /**
 976  * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
 977  * buffer
 978  * @skb: socket buffer to add attribute to
 979  * @attrtype: attribute type
 980  * @addr: IPv6 address
 981  */
 982 static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
 983                                    const struct in6_addr *addr)
 984 {
 985         return nla_put(skb, attrtype, sizeof(*addr), addr);
 986 }
 987
 988 /**
 989  * nla_get_u32 - return payload of u32 attribute
 990  * @nla: u32 netlink attribute
 991  */
 992 static inline u32 nla_get_u32(const struct nlattr *nla)
 993 {
 994         return *(u32 *) nla_data(nla);
 995 }
 996
 997 /**
 998  * nla_get_be32 - return payload of __be32 attribute
 999  * @nla: __be32 netlink attribute
1000  */
1001 static inline __be32 nla_get_be32(const struct nlattr *nla)
1002 {
1003         return *(__be32 *) nla_data(nla);
1004 }
1005
1006 /**
1007  * nla_get_le32 - return payload of __le32 attribute
1008  * @nla: __le32 netlink attribute
1009  */
1010 static inline __le32 nla_get_le32(const struct nlattr *nla)
1011 {
1012         return *(__le32 *) nla_data(nla);
1013 }
1014
1015 /**
1016  * nla_get_u16 - return payload of u16 attribute
1017  * @nla: u16 netlink attribute
1018  */
1019 static inline u16 nla_get_u16(const struct nlattr *nla)
1020 {
1021         return *(u16 *) nla_data(nla);
1022 }
1023
1024 /**
1025  * nla_get_be16 - return payload of __be16 attribute
1026  * @nla: __be16 netlink attribute
1027  */
1028 static inline __be16 nla_get_be16(const struct nlattr *nla)
1029 {
1030         return *(__be16 *) nla_data(nla);
1031 }
1032
1033 /**
1034  * nla_get_le16 - return payload of __le16 attribute
1035  * @nla: __le16 netlink attribute
1036  */
1037 static inline __le16 nla_get_le16(const struct nlattr *nla)
1038 {
1039         return *(__le16 *) nla_data(nla);
1040 }
1041
1042 /**
1043  * nla_get_u8 - return payload of u8 attribute
1044  * @nla: u8 netlink attribute
1045  */
1046 static inline u8 nla_get_u8(const struct nlattr *nla)
1047 {
1048         return *(u8 *) nla_data(nla);
1049 }
1050
1051 /**
1052  * nla_get_u64 - return payload of u64 attribute
1053  * @nla: u64 netlink attribute
1054  */
1055 static inline u64 nla_get_u64(const struct nlattr *nla)
1056 {
1057         u64 tmp;
1058
1059         nla_memcpy(&tmp, nla, sizeof(tmp));
1060
1061         return tmp;
1062 }
1063
1064 /**
1065  * nla_get_be64 - return payload of __be64 attribute
1066  * @nla: __be64 netlink attribute
1067  */
1068 static inline __be64 nla_get_be64(const struct nlattr *nla)
1069 {
1070         __be64 tmp;
1071
1072         nla_memcpy(&tmp, nla, sizeof(tmp));
1073
1074         return tmp;
1075 }
1076
1077 /**
1078  * nla_get_le64 - return payload of __le64 attribute
1079  * @nla: __le64 netlink attribute
1080  */
1081 static inline __le64 nla_get_le64(const struct nlattr *nla)
1082 {
1083         return *(__le64 *) nla_data(nla);
1084 }
1085
1086 /**
1087  * nla_get_s32 - return payload of s32 attribute
1088  * @nla: s32 netlink attribute
1089  */
1090 static inline s32 nla_get_s32(const struct nlattr *nla)
1091 {
1092         return *(s32 *) nla_data(nla);
1093 }
1094
1095 /**
1096  * nla_get_s16 - return payload of s16 attribute
1097  * @nla: s16 netlink attribute
1098  */
1099 static inline s16 nla_get_s16(const struct nlattr *nla)
1100 {
1101         return *(s16 *) nla_data(nla);
1102 }
1103
1104 /**
1105  * nla_get_s8 - return payload of s8 attribute
1106  * @nla: s8 netlink attribute
1107  */
1108 static inline s8 nla_get_s8(const struct nlattr *nla)
1109 {
1110         return *(s8 *) nla_data(nla);
1111 }
1112
1113 /**
1114  * nla_get_s64 - return payload of s64 attribute
1115  * @nla: s64 netlink attribute
1116  */
1117 static inline s64 nla_get_s64(const struct nlattr *nla)
1118 {
1119         s64 tmp;
1120
1121         nla_memcpy(&tmp, nla, sizeof(tmp));
1122
1123         return tmp;
1124 }
1125
1126 /**
1127  * nla_get_flag - return payload of flag attribute
1128  * @nla: flag netlink attribute
1129  */
1130 static inline int nla_get_flag(const struct nlattr *nla)
1131 {
1132         return !!nla;
1133 }
1134
1135 /**
1136  * nla_get_msecs - return payload of msecs attribute
1137  * @nla: msecs netlink attribute
1138  *
1139  * Returns the number of milliseconds in jiffies.
1140  */
1141 static inline unsigned long nla_get_msecs(const struct nlattr *nla)
1142 {
1143         u64 msecs = nla_get_u64(nla);
1144
1145         return msecs_to_jiffies((unsigned long) msecs);
1146 }
1147
1148 /**
1149  * nla_get_in_addr - return payload of IPv4 address attribute
1150  * @nla: IPv4 address netlink attribute
1151  */
1152 static inline __be32 nla_get_in_addr(const struct nlattr *nla)
1153 {
1154         return *(__be32 *) nla_data(nla);
1155 }
1156
1157 /**
1158  * nla_get_in6_addr - return payload of IPv6 address attribute
1159  * @nla: IPv6 address netlink attribute
1160  */
1161 static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
1162 {
1163         struct in6_addr tmp;
1164
1165         nla_memcpy(&tmp, nla, sizeof(tmp));
1166         return tmp;
1167 }
1168
1169 /**
1170  * nla_nest_start - Start a new level of nested attributes
1171  * @skb: socket buffer to add attributes to
1172  * @attrtype: attribute type of container
1173  *
1174  * Returns the container attribute
1175  */
1176 static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
1177 {
1178         struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
1179
1180         if (nla_put(skb, attrtype, 0, NULL) < 0)
1181                 return NULL;
1182
1183         return start;
1184 }
1185
1186 /**
1187  * nla_nest_end - Finalize nesting of attributes
1188  * @skb: socket buffer the attributes are stored in
1189  * @start: container attribute
1190  *
1191  * Corrects the container attribute header to include the all
1192  * appeneded attributes.
1193  *
1194  * Returns the total data length of the skb.
1195  */
1196 static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
1197 {
1198         start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
1199         return skb->len;
1200 }
1201
1202 /**
1203  * nla_nest_cancel - Cancel nesting of attributes
1204  * @skb: socket buffer the message is stored in
1205  * @start: container attribute
1206  *
1207  * Removes the container attribute and including all nested
1208  * attributes. Returns -EMSGSIZE
1209  */
1210 static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
1211 {
1212         nlmsg_trim(skb, start);
1213 }
1214
1215 /**
1216  * nla_validate_nested - Validate a stream of nested attributes
1217  * @start: container attribute
1218  * @maxtype: maximum attribute type to be expected
1219  * @policy: validation policy
1220  *
1221  * Validates all attributes in the nested attribute stream against the
1222  * specified policy. Attributes with a type exceeding maxtype will be
1223  * ignored. See documenation of struct nla_policy for more details.
1224  *
1225  * Returns 0 on success or a negative error code.
1226  */
1227 static inline int nla_validate_nested(const struct nlattr *start, int maxtype,
1228                                       const struct nla_policy *policy)
1229 {
1230         return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
1231 }
1232
1233 /**
1234  * nla_for_each_attr - iterate over a stream of attributes
1235  * @pos: loop counter, set to current attribute
1236  * @head: head of attribute stream
1237  * @len: length of attribute stream
1238  * @rem: initialized to len, holds bytes currently remaining in stream
1239  */
1240 #define nla_for_each_attr(pos, head, len, rem) \
1241         for (pos = head, rem = len; \
1242              nla_ok(pos, rem); \
1243              pos = nla_next(pos, &(rem)))
1244
1245 /**
1246  * nla_for_each_nested - iterate over nested attributes
1247  * @pos: loop counter, set to current attribute
1248  * @nla: attribute containing the nested attributes
1249  * @rem: initialized to len, holds bytes currently remaining in stream
1250  */
1251 #define nla_for_each_nested(pos, nla, rem) \
1252         nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)
1253
1254 /**
1255  * nla_is_last - Test if attribute is last in stream
1256  * @nla: attribute to test
1257  * @rem: bytes remaining in stream
1258  */
1259 static inline bool nla_is_last(const struct nlattr *nla, int rem)
1260 {
1261         return nla->nla_len == rem;
1262 }
1263
1264 #endif