lib/nlattr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * NETLINK      Netlink attributes
   4  *
   5  *              Authors:        Thomas Graf <tgraf@suug.ch>
   6  *                              Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
   7  */
   8
   9 #include <linux/export.h>
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/jiffies.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/string.h>
  15 #include <linux/types.h>
  16 #include <net/netlink.h>
  17
  18 /* for these data types attribute length must be exactly given size */
  19 static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
  20         [NLA_U8]        = sizeof(u8),
  21         [NLA_U16]       = sizeof(u16),
  22         [NLA_U32]       = sizeof(u32),
  23         [NLA_U64]       = sizeof(u64),
  24         [NLA_S8]        = sizeof(s8),
  25         [NLA_S16]       = sizeof(s16),
  26         [NLA_S32]       = sizeof(s32),
  27         [NLA_S64]       = sizeof(s64),
  28 };
  29
  30 static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
  31         [NLA_MSECS]     = sizeof(u64),
  32         [NLA_NESTED]    = NLA_HDRLEN,
  33 };
  34
  35 static int validate_nla_bitfield32(const struct nlattr *nla,
  36                                    u32 *valid_flags_allowed)
  37 {
  38         const struct nla_bitfield32 *bf = nla_data(nla);
  39         u32 *valid_flags_mask = valid_flags_allowed;
  40
  41         if (!valid_flags_allowed)
  42                 return -EINVAL;
  43
  44         /*disallow invalid bit selector */
  45         if (bf->selector & ~*valid_flags_mask)
  46                 return -EINVAL;
  47
  48         /*disallow invalid bit values */
  49         if (bf->value & ~*valid_flags_mask)
  50                 return -EINVAL;
  51
  52         /*disallow valid bit values that are not selected*/
  53         if (bf->value & ~bf->selector)
  54                 return -EINVAL;
  55
  56         return 0;
  57 }
  58
  59 static int validate_nla(const struct nlattr *nla, int maxtype,
  60                         const struct nla_policy *policy)
  61 {
  62         const struct nla_policy *pt;
  63         int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
  64
  65         if (type <= 0 || type > maxtype)
  66                 return 0;
  67
  68         pt = &policy[type];
  69
  70         BUG_ON(pt->type > NLA_TYPE_MAX);
  71
  72         /* for data types NLA_U* and NLA_S* require exact length */
  73         if (nla_attr_len[pt->type]) {
  74                 if (attrlen != nla_attr_len[pt->type])
  75                         return -ERANGE;
  76                 return 0;
  77         }
  78
  79         switch (pt->type) {
  80         case NLA_FLAG:
  81                 if (attrlen > 0)
  82                         return -ERANGE;
  83                 break;
  84
  85         case NLA_BITFIELD32:
  86                 if (attrlen != sizeof(struct nla_bitfield32))
  87                         return -ERANGE;
  88
  89                 return validate_nla_bitfield32(nla, pt->validation_data);
  90
  91         case NLA_NUL_STRING:
  92                 if (pt->len)
  93                         minlen = min_t(int, attrlen, pt->len + 1);
  94                 else
  95                         minlen = attrlen;
  96
  97                 if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL)
  98                         return -EINVAL;
  99                 /* fall through */
 100
 101         case NLA_STRING:
 102                 if (attrlen < 1)
 103                         return -ERANGE;
 104
 105                 if (pt->len) {
 106                         char *buf = nla_data(nla);
 107
 108                         if (buf[attrlen - 1] == '\0')
 109                                 attrlen--;
 110
 111                         if (attrlen > pt->len)
 112                                 return -ERANGE;
 113                 }
 114                 break;
 115
 116         case NLA_BINARY:
 117                 if (pt->len && attrlen > pt->len)
 118                         return -ERANGE;
 119                 break;
 120
 121         case NLA_NESTED_COMPAT:
 122                 if (attrlen < pt->len)
 123                         return -ERANGE;
 124                 if (attrlen < NLA_ALIGN(pt->len))
 125                         break;
 126                 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
 127                         return -ERANGE;
 128                 nla = nla_data(nla) + NLA_ALIGN(pt->len);
 129                 if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
 130                         return -ERANGE;
 131                 break;
 132         case NLA_NESTED:
 133                 /* a nested attributes is allowed to be empty; if its not,
 134                  * it must have a size of at least NLA_HDRLEN.
 135                  */
 136                 if (attrlen == 0)
 137                         break;
 138         default:
 139                 if (pt->len)
 140                         minlen = pt->len;
 141                 else if (pt->type != NLA_UNSPEC)
 142                         minlen = nla_attr_minlen[pt->type];
 143
 144                 if (attrlen < minlen)
 145                         return -ERANGE;
 146         }
 147
 148         return 0;
 149 }
 150
 151 /**
 152  * nla_validate - Validate a stream of attributes
 153  * @head: head of attribute stream
 154  * @len: length of attribute stream
 155  * @maxtype: maximum attribute type to be expected
 156  * @policy: validation policy
 157  * @extack: extended ACK report struct
 158  *
 159  * Validates all attributes in the specified attribute stream against the
 160  * specified policy. Attributes with a type exceeding maxtype will be
 161  * ignored. See documenation of struct nla_policy for more details.
 162  *
 163  * Returns 0 on success or a negative error code.
 164  */
 165 int nla_validate(const struct nlattr *head, int len, int maxtype,
 166                  const struct nla_policy *policy,
 167                  struct netlink_ext_ack *extack)
 168 {
 169         const struct nlattr *nla;
 170         int rem;
 171
 172         nla_for_each_attr(nla, head, len, rem) {
 173                 int err = validate_nla(nla, maxtype, policy);
 174
 175                 if (err < 0) {
 176                         if (extack)
 177                                 extack->bad_attr = nla;
 178                         return err;
 179                 }
 180         }
 181
 182         return 0;
 183 }
 184 EXPORT_SYMBOL(nla_validate);
 185
 186 /**
 187  * nla_policy_len - Determin the max. length of a policy
 188  * @policy: policy to use
 189  * @n: number of policies
 190  *
 191  * Determines the max. length of the policy.  It is currently used
 192  * to allocated Netlink buffers roughly the size of the actual
 193  * message.
 194  *
 195  * Returns 0 on success or a negative error code.
 196  */
 197 int
 198 nla_policy_len(const struct nla_policy *p, int n)
 199 {
 200         int i, len = 0;
 201
 202         for (i = 0; i < n; i++, p++) {
 203                 if (p->len)
 204                         len += nla_total_size(p->len);
 205                 else if (nla_attr_len[p->type])
 206                         len += nla_total_size(nla_attr_len[p->type]);
 207                 else if (nla_attr_minlen[p->type])
 208                         len += nla_total_size(nla_attr_minlen[p->type]);
 209         }
 210
 211         return len;
 212 }
 213 EXPORT_SYMBOL(nla_policy_len);
 214
 215 /**
 216  * nla_parse - Parse a stream of attributes into a tb buffer
 217  * @tb: destination array with maxtype+1 elements
 218  * @maxtype: maximum attribute type to be expected
 219  * @head: head of attribute stream
 220  * @len: length of attribute stream
 221  * @policy: validation policy
 222  *
 223  * Parses a stream of attributes and stores a pointer to each attribute in
 224  * the tb array accessible via the attribute type. Attributes with a type
 225  * exceeding maxtype will be silently ignored for backwards compatibility
 226  * reasons. policy may be set to NULL if no validation is required.
 227  *
 228  * Returns 0 on success or a negative error code.
 229  */
 230 int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 231               int len, const struct nla_policy *policy,
 232               struct netlink_ext_ack *extack)
 233 {
 234         const struct nlattr *nla;
 235         int rem, err;
 236
 237         memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
 238
 239         nla_for_each_attr(nla, head, len, rem) {
 240                 u16 type = nla_type(nla);
 241
 242                 if (type > 0 && type <= maxtype) {
 243                         if (policy) {
 244                                 err = validate_nla(nla, maxtype, policy);
 245                                 if (err < 0) {
 246                                         if (extack)
 247                                                 extack->bad_attr = nla;
 248                                         goto errout;
 249                                 }
 250                         }
 251
 252                         tb[type] = (struct nlattr *)nla;
 253                 }
 254         }
 255
 256         if (unlikely(rem > 0))
 257                 pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
 258                                     rem, current->comm);
 259
 260         err = 0;
 261 errout:
 262         return err;
 263 }
 264 EXPORT_SYMBOL(nla_parse);
 265
 266 /**
 267  * nla_find - Find a specific attribute in a stream of attributes
 268  * @head: head of attribute stream
 269  * @len: length of attribute stream
 270  * @attrtype: type of attribute to look for
 271  *
 272  * Returns the first attribute in the stream matching the specified type.
 273  */
 274 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
 275 {
 276         const struct nlattr *nla;
 277         int rem;
 278
 279         nla_for_each_attr(nla, head, len, rem)
 280                 if (nla_type(nla) == attrtype)
 281                         return (struct nlattr *)nla;
 282
 283         return NULL;
 284 }
 285 EXPORT_SYMBOL(nla_find);
 286
 287 /**
 288  * nla_strlcpy - Copy string attribute payload into a sized buffer
 289  * @dst: where to copy the string to
 290  * @nla: attribute to copy the string from
 291  * @dstsize: size of destination buffer
 292  *
 293  * Copies at most dstsize - 1 bytes into the destination buffer.
 294  * The result is always a valid NUL-terminated string. Unlike
 295  * strlcpy the destination buffer is always padded out.
 296  *
 297  * Returns the length of the source buffer.
 298  */
 299 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
 300 {
 301         size_t srclen = nla_len(nla);
 302         char *src = nla_data(nla);
 303
 304         if (srclen > 0 && src[srclen - 1] == '\0')
 305                 srclen--;
 306
 307         if (dstsize > 0) {
 308                 size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
 309
 310                 memset(dst, 0, dstsize);
 311                 memcpy(dst, src, len);
 312         }
 313
 314         return srclen;
 315 }
 316 EXPORT_SYMBOL(nla_strlcpy);
 317
 318 /**
 319  * nla_strdup - Copy string attribute payload into a newly allocated buffer
 320  * @nla: attribute to copy the string from
 321  * @flags: the type of memory to allocate (see kmalloc).
 322  *
 323  * Returns a pointer to the allocated buffer or NULL on error.
 324  */
 325 char *nla_strdup(const struct nlattr *nla, gfp_t flags)
 326 {
 327         size_t srclen = nla_len(nla);
 328         char *src = nla_data(nla), *dst;
 329
 330         if (srclen > 0 && src[srclen - 1] == '\0')
 331                 srclen--;
 332
 333         dst = kmalloc(srclen + 1, flags);
 334         if (dst != NULL) {
 335                 memcpy(dst, src, srclen);
 336                 dst[srclen] = '\0';
 337         }
 338         return dst;
 339 }
 340 EXPORT_SYMBOL(nla_strdup);
 341
 342 /**
 343  * nla_memcpy - Copy a netlink attribute into another memory area
 344  * @dest: where to copy to memcpy
 345  * @src: netlink attribute to copy from
 346  * @count: size of the destination area
 347  *
 348  * Note: The number of bytes copied is limited by the length of
 349  *       attribute's payload. memcpy
 350  *
 351  * Returns the number of bytes copied.
 352  */
 353 int nla_memcpy(void *dest, const struct nlattr *src, int count)
 354 {
 355         int minlen = min_t(int, count, nla_len(src));
 356
 357         memcpy(dest, nla_data(src), minlen);
 358         if (count > minlen)
 359                 memset(dest + minlen, 0, count - minlen);
 360
 361         return minlen;
 362 }
 363 EXPORT_SYMBOL(nla_memcpy);
 364
 365 /**
 366  * nla_memcmp - Compare an attribute with sized memory area
 367  * @nla: netlink attribute
 368  * @data: memory area
 369  * @size: size of memory area
 370  */
 371 int nla_memcmp(const struct nlattr *nla, const void *data,
 372                              size_t size)
 373 {
 374         int d = nla_len(nla) - size;
 375
 376         if (d == 0)
 377                 d = memcmp(nla_data(nla), data, size);
 378
 379         return d;
 380 }
 381 EXPORT_SYMBOL(nla_memcmp);
 382
 383 /**
 384  * nla_strcmp - Compare a string attribute against a string
 385  * @nla: netlink string attribute
 386  * @str: another string
 387  */
 388 int nla_strcmp(const struct nlattr *nla, const char *str)
 389 {
 390         int len = strlen(str);
 391         char *buf = nla_data(nla);
 392         int attrlen = nla_len(nla);
 393         int d;
 394
 395         if (attrlen > 0 && buf[attrlen - 1] == '\0')
 396                 attrlen--;
 397
 398         d = attrlen - len;
 399         if (d == 0)
 400                 d = memcmp(nla_data(nla), str, len);
 401
 402         return d;
 403 }
 404 EXPORT_SYMBOL(nla_strcmp);
 405
 406 #ifdef CONFIG_NET
 407 /**
 408  * __nla_reserve - reserve room for attribute on the skb
 409  * @skb: socket buffer to reserve room on
 410  * @attrtype: attribute type
 411  * @attrlen: length of attribute payload
 412  *
 413  * Adds a netlink attribute header to a socket buffer and reserves
 414  * room for the payload but does not copy it.
 415  *
 416  * The caller is responsible to ensure that the skb provides enough
 417  * tailroom for the attribute header and payload.
 418  */
 419 struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
 420 {
 421         struct nlattr *nla;
 422
 423         nla = skb_put(skb, nla_total_size(attrlen));
 424         nla->nla_type = attrtype;
 425         nla->nla_len = nla_attr_size(attrlen);
 426
 427         memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
 428
 429         return nla;
 430 }
 431 EXPORT_SYMBOL(__nla_reserve);
 432
 433 /**
 434  * __nla_reserve_64bit - reserve room for attribute on the skb and align it
 435  * @skb: socket buffer to reserve room on
 436  * @attrtype: attribute type
 437  * @attrlen: length of attribute payload
 438  * @padattr: attribute type for the padding
 439  *
 440  * Adds a netlink attribute header to a socket buffer and reserves
 441  * room for the payload but does not copy it. It also ensure that this
 442  * attribute will have a 64-bit aligned nla_data() area.
 443  *
 444  * The caller is responsible to ensure that the skb provides enough
 445  * tailroom for the attribute header and payload.
 446  */
 447 struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
 448                                    int attrlen, int padattr)
 449 {
 450         if (nla_need_padding_for_64bit(skb))
 451                 nla_align_64bit(skb, padattr);
 452
 453         return __nla_reserve(skb, attrtype, attrlen);
 454 }
 455 EXPORT_SYMBOL(__nla_reserve_64bit);
 456
 457 /**
 458  * __nla_reserve_nohdr - reserve room for attribute without header
 459  * @skb: socket buffer to reserve room on
 460  * @attrlen: length of attribute payload
 461  *
 462  * Reserves room for attribute payload without a header.
 463  *
 464  * The caller is responsible to ensure that the skb provides enough
 465  * tailroom for the payload.
 466  */
 467 void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
 468 {
 469         return skb_put_zero(skb, NLA_ALIGN(attrlen));
 470 }
 471 EXPORT_SYMBOL(__nla_reserve_nohdr);
 472
 473 /**
 474  * nla_reserve - reserve room for attribute on the skb
 475  * @skb: socket buffer to reserve room on
 476  * @attrtype: attribute type
 477  * @attrlen: length of attribute payload
 478  *
 479  * Adds a netlink attribute header to a socket buffer and reserves
 480  * room for the payload but does not copy it.
 481  *
 482  * Returns NULL if the tailroom of the skb is insufficient to store
 483  * the attribute header and payload.
 484  */
 485 struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
 486 {
 487         if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
 488                 return NULL;
 489
 490         return __nla_reserve(skb, attrtype, attrlen);
 491 }
 492 EXPORT_SYMBOL(nla_reserve);
 493
 494 /**
 495  * nla_reserve_64bit - reserve room for attribute on the skb and align it
 496  * @skb: socket buffer to reserve room on
 497  * @attrtype: attribute type
 498  * @attrlen: length of attribute payload
 499  * @padattr: attribute type for the padding
 500  *
 501  * Adds a netlink attribute header to a socket buffer and reserves
 502  * room for the payload but does not copy it. It also ensure that this
 503  * attribute will have a 64-bit aligned nla_data() area.
 504  *
 505  * Returns NULL if the tailroom of the skb is insufficient to store
 506  * the attribute header and payload.
 507  */
 508 struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 509                                  int padattr)
 510 {
 511         size_t len;
 512
 513         if (nla_need_padding_for_64bit(skb))
 514                 len = nla_total_size_64bit(attrlen);
 515         else
 516                 len = nla_total_size(attrlen);
 517         if (unlikely(skb_tailroom(skb) < len))
 518                 return NULL;
 519
 520         return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
 521 }
 522 EXPORT_SYMBOL(nla_reserve_64bit);
 523
 524 /**
 525  * nla_reserve_nohdr - reserve room for attribute without header
 526  * @skb: socket buffer to reserve room on
 527  * @attrlen: length of attribute payload
 528  *
 529  * Reserves room for attribute payload without a header.
 530  *
 531  * Returns NULL if the tailroom of the skb is insufficient to store
 532  * the attribute payload.
 533  */
 534 void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
 535 {
 536         if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
 537                 return NULL;
 538
 539         return __nla_reserve_nohdr(skb, attrlen);
 540 }
 541 EXPORT_SYMBOL(nla_reserve_nohdr);
 542
 543 /**
 544  * __nla_put - Add a netlink attribute to a socket buffer
 545  * @skb: socket buffer to add attribute to
 546  * @attrtype: attribute type
 547  * @attrlen: length of attribute payload
 548  * @data: head of attribute payload
 549  *
 550  * The caller is responsible to ensure that the skb provides enough
 551  * tailroom for the attribute header and payload.
 552  */
 553 void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
 554                              const void *data)
 555 {
 556         struct nlattr *nla;
 557
 558         nla = __nla_reserve(skb, attrtype, attrlen);
 559         memcpy(nla_data(nla), data, attrlen);
 560 }
 561 EXPORT_SYMBOL(__nla_put);
 562
 563 /**
 564  * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
 565  * @skb: socket buffer to add attribute to
 566  * @attrtype: attribute type
 567  * @attrlen: length of attribute payload
 568  * @data: head of attribute payload
 569  * @padattr: attribute type for the padding
 570  *
 571  * The caller is responsible to ensure that the skb provides enough
 572  * tailroom for the attribute header and payload.
 573  */
 574 void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 575                      const void *data, int padattr)
 576 {
 577         struct nlattr *nla;
 578
 579         nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
 580         memcpy(nla_data(nla), data, attrlen);
 581 }
 582 EXPORT_SYMBOL(__nla_put_64bit);
 583
 584 /**
 585  * __nla_put_nohdr - Add a netlink attribute without header
 586  * @skb: socket buffer to add attribute to
 587  * @attrlen: length of attribute payload
 588  * @data: head of attribute payload
 589  *
 590  * The caller is responsible to ensure that the skb provides enough
 591  * tailroom for the attribute payload.
 592  */
 593 void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
 594 {
 595         void *start;
 596
 597         start = __nla_reserve_nohdr(skb, attrlen);
 598         memcpy(start, data, attrlen);
 599 }
 600 EXPORT_SYMBOL(__nla_put_nohdr);
 601
 602 /**
 603  * nla_put - Add a netlink attribute to a socket buffer
 604  * @skb: socket buffer to add attribute to
 605  * @attrtype: attribute type
 606  * @attrlen: length of attribute payload
 607  * @data: head of attribute payload
 608  *
 609  * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
 610  * the attribute header and payload.
 611  */
 612 int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
 613 {
 614         if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
 615                 return -EMSGSIZE;
 616
 617         __nla_put(skb, attrtype, attrlen, data);
 618         return 0;
 619 }
 620 EXPORT_SYMBOL(nla_put);
 621
 622 /**
 623  * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
 624  * @skb: socket buffer to add attribute to
 625  * @attrtype: attribute type
 626  * @attrlen: length of attribute payload
 627  * @data: head of attribute payload
 628  * @padattr: attribute type for the padding
 629  *
 630  * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
 631  * the attribute header and payload.
 632  */
 633 int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
 634                   const void *data, int padattr)
 635 {
 636         size_t len;
 637
 638         if (nla_need_padding_for_64bit(skb))
 639                 len = nla_total_size_64bit(attrlen);
 640         else
 641                 len = nla_total_size(attrlen);
 642         if (unlikely(skb_tailroom(skb) < len))
 643                 return -EMSGSIZE;
 644
 645         __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
 646         return 0;
 647 }
 648 EXPORT_SYMBOL(nla_put_64bit);
 649
 650 /**
 651  * nla_put_nohdr - Add a netlink attribute without header
 652  * @skb: socket buffer to add attribute to
 653  * @attrlen: length of attribute payload
 654  * @data: head of attribute payload
 655  *
 656  * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
 657  * the attribute payload.
 658  */
 659 int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
 660 {
 661         if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
 662                 return -EMSGSIZE;
 663
 664         __nla_put_nohdr(skb, attrlen, data);
 665         return 0;
 666 }
 667 EXPORT_SYMBOL(nla_put_nohdr);
 668
 669 /**
 670  * nla_append - Add a netlink attribute without header or padding
 671  * @skb: socket buffer to add attribute to
 672  * @attrlen: length of attribute payload
 673  * @data: head of attribute payload
 674  *
 675  * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
 676  * the attribute payload.
 677  */
 678 int nla_append(struct sk_buff *skb, int attrlen, const void *data)
 679 {
 680         if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
 681                 return -EMSGSIZE;
 682
 683         skb_put_data(skb, data, attrlen);
 684         return 0;
 685 }
 686 EXPORT_SYMBOL(nla_append);
 687 #endif