// SPDX-License-Identifier: GPL-2.0

  /*
   * NETLINK      Netlink attributes
   *
   * 		Authors:	Thomas Graf <tgraf@suug.ch>
   * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
   */

  #include <linux/export.h>

  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/jiffies.h>

  #include <linux/skbuff.h>
  #include <linux/string.h>
  #include <linux/types.h>
  #include <net/netlink.h>

  /* For these data types, attribute length should be exactly the given
   * size. However, to maintain compatibility with broken commands, if the
   * attribute length does not match the expected size a warning is emitted
   * to the user that the command is sending invalid data and needs to be fixed.
   */

  static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {

  	[NLA_U8]	= sizeof(u8),
  	[NLA_U16]	= sizeof(u16),
  	[NLA_U32]	= sizeof(u32),
  	[NLA_U64]	= sizeof(u64),

  	[NLA_S8]	= sizeof(s8),
  	[NLA_S16]	= sizeof(s16),
  	[NLA_S32]	= sizeof(s32),
  	[NLA_S64]	= sizeof(s64),

  };

  static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {

  	[NLA_U8]	= sizeof(u8),
  	[NLA_U16]	= sizeof(u16),
  	[NLA_U32]	= sizeof(u32),
  	[NLA_U64]	= sizeof(u64),

  	[NLA_MSECS]	= sizeof(u64),
  	[NLA_NESTED]	= NLA_HDRLEN,

  	[NLA_S8]	= sizeof(s8),
  	[NLA_S16]	= sizeof(s16),
  	[NLA_S32]	= sizeof(s32),
  	[NLA_S64]	= sizeof(s64),

  };

  /*
   * Nested policies might refer back to the original
   * policy in some cases, and userspace could try to
   * abuse that and recurse by nesting in the right
   * ways. Limit recursion to avoid this problem.
   */
  #define MAX_POLICY_RECURSION_DEPTH	10
  
  static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
  				const struct nla_policy *policy,
  				unsigned int validate,
  				struct netlink_ext_ack *extack,
  				struct nlattr **tb, unsigned int depth);

  static int validate_nla_bitfield32(const struct nlattr *nla,

  				   const u32 valid_flags_mask)

  {
  	const struct nla_bitfield32 *bf = nla_data(nla);

  	if (!valid_flags_mask)

  		return -EINVAL;
  
  	/*disallow invalid bit selector */

  	if (bf->selector & ~valid_flags_mask)

  		return -EINVAL;
  
  	/*disallow invalid bit values */

  	if (bf->value & ~valid_flags_mask)

  		return -EINVAL;
  
  	/*disallow valid bit values that are not selected*/
  	if (bf->value & ~bf->selector)
  		return -EINVAL;
  
  	return 0;
  }

  static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
  			      const struct nla_policy *policy,

  			      struct netlink_ext_ack *extack,

  			      unsigned int validate, unsigned int depth)

  {
  	const struct nlattr *entry;
  	int rem;
  
  	nla_for_each_attr(entry, head, len, rem) {
  		int ret;
  
  		if (nla_len(entry) == 0)
  			continue;
  
  		if (nla_len(entry) < NLA_HDRLEN) {

  			NL_SET_ERR_MSG_ATTR_POL(extack, entry, policy,
  						"Array element too short");

  			return -ERANGE;
  		}

  		ret = __nla_validate_parse(nla_data(entry), nla_len(entry),
  					   maxtype, policy, validate, extack,
  					   NULL, depth + 1);

  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }

  void nla_get_range_unsigned(const struct nla_policy *pt,
  			    struct netlink_range_validation *range)

  {

  	WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR &&
  		     (pt->min < 0 || pt->max < 0));

  	range->min = 0;
  
  	switch (pt->type) {
  	case NLA_U8:
  		range->max = U8_MAX;
  		break;
  	case NLA_U16:

  	case NLA_BINARY:

  		range->max = U16_MAX;
  		break;
  	case NLA_U32:
  		range->max = U32_MAX;
  		break;
  	case NLA_U64:
  	case NLA_MSECS:
  		range->max = U64_MAX;
  		break;
  	default:
  		WARN_ON_ONCE(1);
  		return;
  	}

  	switch (pt->validation_type) {
  	case NLA_VALIDATE_RANGE:

  	case NLA_VALIDATE_RANGE_WARN_TOO_LONG:

  		range->min = pt->min;
  		range->max = pt->max;
  		break;
  	case NLA_VALIDATE_RANGE_PTR:

  		*range = *pt->range;

  		break;
  	case NLA_VALIDATE_MIN:
  		range->min = pt->min;
  		break;
  	case NLA_VALIDATE_MAX:
  		range->max = pt->max;
  		break;

  	default:
  		break;

  	}

  }

  static int nla_validate_range_unsigned(const struct nla_policy *pt,
  				       const struct nlattr *nla,
  				       struct netlink_ext_ack *extack,
  				       unsigned int validate)

  {
  	struct netlink_range_validation range;
  	u64 value;

  
  	switch (pt->type) {
  	case NLA_U8:
  		value = nla_get_u8(nla);
  		break;
  	case NLA_U16:
  		value = nla_get_u16(nla);
  		break;
  	case NLA_U32:
  		value = nla_get_u32(nla);
  		break;

  	case NLA_U64:

  	case NLA_MSECS:

  		value = nla_get_u64(nla);
  		break;

  	case NLA_BINARY:
  		value = nla_len(nla);
  		break;

  	default:
  		return -EINVAL;
  	}

  	nla_get_range_unsigned(pt, &range);

  	if (pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG &&
  	    pt->type == NLA_BINARY && value > range.max) {
  		pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.
  ",
  				    current->comm, pt->type);
  		if (validate & NL_VALIDATE_STRICT_ATTRS) {

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"invalid attribute length");

  			return -EINVAL;
  		}
  
  		/* this assumes min <= max (don't validate against min) */
  		return 0;
  	}

  	if (value < range.min || value > range.max) {

  		bool binary = pt->type == NLA_BINARY;
  
  		if (binary)

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"binary attribute size out of range");

  		else

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"integer out of range");

  		return -ERANGE;
  	}
  
  	return 0;
  }

  void nla_get_range_signed(const struct nla_policy *pt,
  			  struct netlink_range_validation_signed *range)

  {

  	switch (pt->type) {
  	case NLA_S8:
  		range->min = S8_MIN;
  		range->max = S8_MAX;
  		break;
  	case NLA_S16:
  		range->min = S16_MIN;
  		range->max = S16_MAX;
  		break;
  	case NLA_S32:
  		range->min = S32_MIN;
  		range->max = S32_MAX;
  		break;
  	case NLA_S64:
  		range->min = S64_MIN;
  		range->max = S64_MAX;
  		break;
  	default:
  		WARN_ON_ONCE(1);
  		return;
  	}

  
  	switch (pt->validation_type) {
  	case NLA_VALIDATE_RANGE:
  		range->min = pt->min;
  		range->max = pt->max;
  		break;
  	case NLA_VALIDATE_RANGE_PTR:

  		*range = *pt->range_signed;

  		break;
  	case NLA_VALIDATE_MIN:
  		range->min = pt->min;
  		break;
  	case NLA_VALIDATE_MAX:
  		range->max = pt->max;
  		break;

  	default:
  		break;

  	}

  }
  
  static int nla_validate_int_range_signed(const struct nla_policy *pt,
  					 const struct nlattr *nla,
  					 struct netlink_ext_ack *extack)
  {
  	struct netlink_range_validation_signed range;
  	s64 value;

  
  	switch (pt->type) {

  	case NLA_S8:
  		value = nla_get_s8(nla);
  		break;
  	case NLA_S16:
  		value = nla_get_s16(nla);
  		break;
  	case NLA_S32:
  		value = nla_get_s32(nla);
  		break;
  	case NLA_S64:
  		value = nla_get_s64(nla);
  		break;

  	default:

  		return -EINVAL;
  	}

  	nla_get_range_signed(pt, &range);
  
  	if (value < range.min || value > range.max) {

  		NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  					"integer out of range");

  		return -ERANGE;
  	}
  
  	return 0;
  }

  static int nla_validate_int_range(const struct nla_policy *pt,
  				  const struct nlattr *nla,

  				  struct netlink_ext_ack *extack,
  				  unsigned int validate)

  {
  	switch (pt->type) {
  	case NLA_U8:
  	case NLA_U16:
  	case NLA_U32:
  	case NLA_U64:

  	case NLA_MSECS:

  	case NLA_BINARY:
  		return nla_validate_range_unsigned(pt, nla, extack, validate);

  	case NLA_S8:
  	case NLA_S16:
  	case NLA_S32:
  	case NLA_S64:
  		return nla_validate_int_range_signed(pt, nla, extack);
  	default:
  		WARN_ON(1);
  		return -EINVAL;
  	}
  }

  static int nla_validate_mask(const struct nla_policy *pt,
  			     const struct nlattr *nla,
  			     struct netlink_ext_ack *extack)
  {
  	u64 value;
  
  	switch (pt->type) {
  	case NLA_U8:
  		value = nla_get_u8(nla);
  		break;
  	case NLA_U16:
  		value = nla_get_u16(nla);
  		break;
  	case NLA_U32:
  		value = nla_get_u32(nla);
  		break;
  	case NLA_U64:
  		value = nla_get_u64(nla);
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	if (value & ~(u64)pt->mask) {
  		NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set");
  		return -EINVAL;
  	}
  
  	return 0;
  }

  static int validate_nla(const struct nlattr *nla, int maxtype,

  			const struct nla_policy *policy, unsigned int validate,

  			struct netlink_ext_ack *extack, unsigned int depth)

  {

  	u16 strict_start_type = policy[0].strict_start_type;

  	const struct nla_policy *pt;

  	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);

  	int err = -ERANGE;

  	if (strict_start_type && type >= strict_start_type)
  		validate |= NL_VALIDATE_STRICT;

  	if (type <= 0 || type > maxtype)

  		return 0;

  	pt = &policy[type];

  
  	BUG_ON(pt->type > NLA_TYPE_MAX);

  	if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) {

  		pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.
  ",
  				    current->comm, type);

  		if (validate & NL_VALIDATE_STRICT_ATTRS) {

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"invalid attribute length");

  			return -EINVAL;
  		}

  	}

  	if (validate & NL_VALIDATE_NESTED) {
  		if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&
  		    !(nla->nla_type & NLA_F_NESTED)) {

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"NLA_F_NESTED is missing");

  			return -EINVAL;
  		}
  		if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&
  		    pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {

  			NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  						"NLA_F_NESTED not expected");

  			return -EINVAL;
  		}
  	}

  	switch (pt->type) {

  	case NLA_REJECT:

  		if (extack && pt->reject_message) {

  			NL_SET_BAD_ATTR(extack, nla);

  			extack->_msg = pt->reject_message;

  			return -EINVAL;
  		}
  		err = -EINVAL;
  		goto out_err;

  	case NLA_FLAG:
  		if (attrlen > 0)

  			goto out_err;

  		break;

  	case NLA_BITFIELD32:
  		if (attrlen != sizeof(struct nla_bitfield32))

  			goto out_err;

  		err = validate_nla_bitfield32(nla, pt->bitfield32_valid);

  		if (err)
  			goto out_err;
  		break;

  	case NLA_NUL_STRING:
  		if (pt->len)
  			minlen = min_t(int, attrlen, pt->len + 1);
  		else
  			minlen = attrlen;

  		if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
  			err = -EINVAL;
  			goto out_err;
  		}

  		/* fall through */
  
  	case NLA_STRING:
  		if (attrlen < 1)

  			goto out_err;

  
  		if (pt->len) {
  			char *buf = nla_data(nla);
  
  			if (buf[attrlen - 1] == '\0')
  				attrlen--;
  
  			if (attrlen > pt->len)

  				goto out_err;

  		}
  		break;

  	case NLA_BINARY:
  		if (pt->len && attrlen > pt->len)

  			goto out_err;

  		break;

  	case NLA_NESTED:
  		/* a nested attributes is allowed to be empty; if its not,
  		 * it must have a size of at least NLA_HDRLEN.
  		 */
  		if (attrlen == 0)
  			break;

  		if (attrlen < NLA_HDRLEN)
  			goto out_err;

  		if (pt->nested_policy) {

  			err = __nla_validate_parse(nla_data(nla), nla_len(nla),
  						   pt->len, pt->nested_policy,
  						   validate, extack, NULL,
  						   depth + 1);

  			if (err < 0) {
  				/*
  				 * return directly to preserve the inner
  				 * error message/attribute pointer
  				 */
  				return err;
  			}
  		}
  		break;

  	case NLA_NESTED_ARRAY:
  		/* a nested array attribute is allowed to be empty; if its not,
  		 * it must have a size of at least NLA_HDRLEN.
  		 */
  		if (attrlen == 0)
  			break;
  		if (attrlen < NLA_HDRLEN)
  			goto out_err;

  		if (pt->nested_policy) {

  			int err;
  
  			err = nla_validate_array(nla_data(nla), nla_len(nla),

  						 pt->len, pt->nested_policy,

  						 extack, validate, depth);

  			if (err < 0) {
  				/*
  				 * return directly to preserve the inner
  				 * error message/attribute pointer
  				 */
  				return err;
  			}
  		}
  		break;

  
  	case NLA_UNSPEC:

  		if (validate & NL_VALIDATE_UNSPEC) {
  			NL_SET_ERR_MSG_ATTR(extack, nla,
  					    "Unsupported attribute");
  			return -EINVAL;
  		}

  		if (attrlen < pt->len)
  			goto out_err;
  		break;

  	default:
  		if (pt->len)
  			minlen = pt->len;

  		else

  			minlen = nla_attr_minlen[pt->type];
  
  		if (attrlen < minlen)

  			goto out_err;

  	}

  	/* further validation */
  	switch (pt->validation_type) {
  	case NLA_VALIDATE_NONE:
  		/* nothing to do */
  		break;

  	case NLA_VALIDATE_RANGE_PTR:

  	case NLA_VALIDATE_RANGE:

  	case NLA_VALIDATE_RANGE_WARN_TOO_LONG:

  	case NLA_VALIDATE_MIN:
  	case NLA_VALIDATE_MAX:

  		err = nla_validate_int_range(pt, nla, extack, validate);

  		if (err)
  			return err;
  		break;

  	case NLA_VALIDATE_MASK:
  		err = nla_validate_mask(pt, nla, extack);
  		if (err)
  			return err;
  		break;

  	case NLA_VALIDATE_FUNCTION:
  		if (pt->validate) {
  			err = pt->validate(nla, extack);
  			if (err)
  				return err;
  		}
  		break;

  	}

  	return 0;

  out_err:

  	NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt,
  				"Attribute failed policy validation");

  	return err;

  }

  static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype,
  				const struct nla_policy *policy,
  				unsigned int validate,
  				struct netlink_ext_ack *extack,

  				struct nlattr **tb, unsigned int depth)

  {
  	const struct nlattr *nla;
  	int rem;

  	if (depth >= MAX_POLICY_RECURSION_DEPTH) {
  		NL_SET_ERR_MSG(extack,
  			       "allowed policy recursion depth exceeded");
  		return -EINVAL;
  	}

  	if (tb)
  		memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
  
  	nla_for_each_attr(nla, head, len, rem) {
  		u16 type = nla_type(nla);
  
  		if (type == 0 || type > maxtype) {
  			if (validate & NL_VALIDATE_MAXTYPE) {

  				NL_SET_ERR_MSG_ATTR(extack, nla,
  						    "Unknown attribute type");

  				return -EINVAL;
  			}
  			continue;
  		}
  		if (policy) {
  			int err = validate_nla(nla, maxtype, policy,

  					       validate, extack, depth);

  
  			if (err < 0)
  				return err;
  		}
  
  		if (tb)
  			tb[type] = (struct nlattr *)nla;
  	}
  
  	if (unlikely(rem > 0)) {
  		pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.
  ",
  				    rem, current->comm);
  		NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes");
  		if (validate & NL_VALIDATE_TRAILING)
  			return -EINVAL;
  	}
  
  	return 0;
  }

  /**

   * __nla_validate - Validate a stream of attributes

   * @head: head of attribute stream
   * @len: length of attribute stream
   * @maxtype: maximum attribute type to be expected
   * @policy: validation policy

   * @validate: validation strictness

   * @extack: extended ACK report struct

   *
   * Validates all attributes in the specified attribute stream against the

   * specified policy. Validation depends on the validate flags passed, see
   * &enum netlink_validation for more details on that.
   * See documenation of struct nla_policy for more details.

   *
   * Returns 0 on success or a negative error code.
   */

  int __nla_validate(const struct nlattr *head, int len, int maxtype,
  		   const struct nla_policy *policy, unsigned int validate,
  		   struct netlink_ext_ack *extack)

  {

  	return __nla_validate_parse(head, len, maxtype, policy, validate,

  				    extack, NULL, 0);

  }

  EXPORT_SYMBOL(__nla_validate);

  
  /**

   * nla_policy_len - Determin the max. length of a policy
   * @policy: policy to use
   * @n: number of policies
   *
   * Determines the max. length of the policy.  It is currently used
   * to allocated Netlink buffers roughly the size of the actual
   * message.
   *
   * Returns 0 on success or a negative error code.
   */
  int
  nla_policy_len(const struct nla_policy *p, int n)
  {
  	int i, len = 0;

  	for (i = 0; i < n; i++, p++) {

  		if (p->len)
  			len += nla_total_size(p->len);

  		else if (nla_attr_len[p->type])
  			len += nla_total_size(nla_attr_len[p->type]);

  		else if (nla_attr_minlen[p->type])
  			len += nla_total_size(nla_attr_minlen[p->type]);
  	}
  
  	return len;
  }

  EXPORT_SYMBOL(nla_policy_len);

  
  /**

   * __nla_parse - Parse a stream of attributes into a tb buffer

   * @tb: destination array with maxtype+1 elements
   * @maxtype: maximum attribute type to be expected
   * @head: head of attribute stream
   * @len: length of attribute stream

   * @policy: validation policy

   * @validate: validation strictness
   * @extack: extended ACK pointer

   *
   * Parses a stream of attributes and stores a pointer to each attribute in

   * the tb array accessible via the attribute type.
   * Validation is controlled by the @validate parameter.

   *
   * Returns 0 on success or a negative error code.
   */

  int __nla_parse(struct nlattr **tb, int maxtype,
  		const struct nlattr *head, int len,
  		const struct nla_policy *policy, unsigned int validate,
  		struct netlink_ext_ack *extack)

  {

  	return __nla_validate_parse(head, len, maxtype, policy, validate,

  				    extack, tb, 0);

  }

  EXPORT_SYMBOL(__nla_parse);

  /**
   * nla_find - Find a specific attribute in a stream of attributes
   * @head: head of attribute stream
   * @len: length of attribute stream
   * @attrtype: type of attribute to look for
   *
   * Returns the first attribute in the stream matching the specified type.
   */

  struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)

  {

  	const struct nlattr *nla;

  	int rem;
  
  	nla_for_each_attr(nla, head, len, rem)

  		if (nla_type(nla) == attrtype)

  			return (struct nlattr *)nla;

  
  	return NULL;
  }

  EXPORT_SYMBOL(nla_find);

  
  /**
   * nla_strlcpy - Copy string attribute payload into a sized buffer
   * @dst: where to copy the string to

   * @nla: attribute to copy the string from

   * @dstsize: size of destination buffer
   *
   * Copies at most dstsize - 1 bytes into the destination buffer.
   * The result is always a valid NUL-terminated string. Unlike
   * strlcpy the destination buffer is always padded out.
   *
   * Returns the length of the source buffer.
   */
  size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
  {
  	size_t srclen = nla_len(nla);
  	char *src = nla_data(nla);
  
  	if (srclen > 0 && src[srclen - 1] == '\0')
  		srclen--;
  
  	if (dstsize > 0) {
  		size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
  
  		memset(dst, 0, dstsize);
  		memcpy(dst, src, len);
  	}
  
  	return srclen;
  }

  EXPORT_SYMBOL(nla_strlcpy);

  
  /**

   * nla_strdup - Copy string attribute payload into a newly allocated buffer
   * @nla: attribute to copy the string from
   * @flags: the type of memory to allocate (see kmalloc).
   *
   * Returns a pointer to the allocated buffer or NULL on error.
   */
  char *nla_strdup(const struct nlattr *nla, gfp_t flags)
  {
  	size_t srclen = nla_len(nla);
  	char *src = nla_data(nla), *dst;
  
  	if (srclen > 0 && src[srclen - 1] == '\0')
  		srclen--;
  
  	dst = kmalloc(srclen + 1, flags);
  	if (dst != NULL) {
  		memcpy(dst, src, srclen);
  		dst[srclen] = '\0';
  	}
  	return dst;
  }
  EXPORT_SYMBOL(nla_strdup);
  
  /**

   * nla_memcpy - Copy a netlink attribute into another memory area
   * @dest: where to copy to memcpy
   * @src: netlink attribute to copy from
   * @count: size of the destination area
   *
   * Note: The number of bytes copied is limited by the length of
   *       attribute's payload. memcpy
   *
   * Returns the number of bytes copied.
   */

  int nla_memcpy(void *dest, const struct nlattr *src, int count)

  {
  	int minlen = min_t(int, count, nla_len(src));
  
  	memcpy(dest, nla_data(src), minlen);

  	if (count > minlen)
  		memset(dest + minlen, 0, count - minlen);

  
  	return minlen;
  }

  EXPORT_SYMBOL(nla_memcpy);

  
  /**
   * nla_memcmp - Compare an attribute with sized memory area
   * @nla: netlink attribute
   * @data: memory area
   * @size: size of memory area
   */
  int nla_memcmp(const struct nlattr *nla, const void *data,
  			     size_t size)
  {
  	int d = nla_len(nla) - size;
  
  	if (d == 0)
  		d = memcmp(nla_data(nla), data, size);
  
  	return d;
  }

  EXPORT_SYMBOL(nla_memcmp);

  
  /**
   * nla_strcmp - Compare a string attribute against a string
   * @nla: netlink string attribute
   * @str: another string
   */
  int nla_strcmp(const struct nlattr *nla, const char *str)
  {

  	int len = strlen(str);
  	char *buf = nla_data(nla);
  	int attrlen = nla_len(nla);
  	int d;

  	if (attrlen > 0 && buf[attrlen - 1] == '\0')
  		attrlen--;
  
  	d = attrlen - len;

  	if (d == 0)
  		d = memcmp(nla_data(nla), str, len);
  
  	return d;
  }

  EXPORT_SYMBOL(nla_strcmp);

  #ifdef CONFIG_NET

  /**
   * __nla_reserve - reserve room for attribute on the skb
   * @skb: socket buffer to reserve room on
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   *
   * Adds a netlink attribute header to a socket buffer and reserves
   * room for the payload but does not copy it.
   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the attribute header and payload.
   */
  struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
  {
  	struct nlattr *nla;

  	nla = skb_put(skb, nla_total_size(attrlen));

  	nla->nla_type = attrtype;
  	nla->nla_len = nla_attr_size(attrlen);
  
  	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
  
  	return nla;
  }

  EXPORT_SYMBOL(__nla_reserve);

  
  /**

   * __nla_reserve_64bit - reserve room for attribute on the skb and align it
   * @skb: socket buffer to reserve room on
   * @attrtype: attribute type
   * @attrlen: length of attribute payload

   * @padattr: attribute type for the padding

   *
   * Adds a netlink attribute header to a socket buffer and reserves
   * room for the payload but does not copy it. It also ensure that this

   * attribute will have a 64-bit aligned nla_data() area.

   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the attribute header and payload.
   */
  struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
  				   int attrlen, int padattr)
  {

  	nla_align_64bit(skb, padattr);

  
  	return __nla_reserve(skb, attrtype, attrlen);
  }
  EXPORT_SYMBOL(__nla_reserve_64bit);
  
  /**

   * __nla_reserve_nohdr - reserve room for attribute without header
   * @skb: socket buffer to reserve room on
   * @attrlen: length of attribute payload
   *
   * Reserves room for attribute payload without a header.
   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the payload.
   */
  void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
  {

  	return skb_put_zero(skb, NLA_ALIGN(attrlen));

  }

  EXPORT_SYMBOL(__nla_reserve_nohdr);

  
  /**

   * nla_reserve - reserve room for attribute on the skb
   * @skb: socket buffer to reserve room on
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   *
   * Adds a netlink attribute header to a socket buffer and reserves
   * room for the payload but does not copy it.
   *
   * Returns NULL if the tailroom of the skb is insufficient to store
   * the attribute header and payload.
   */
  struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
  {
  	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
  		return NULL;
  
  	return __nla_reserve(skb, attrtype, attrlen);
  }

  EXPORT_SYMBOL(nla_reserve);

  
  /**

   * nla_reserve_64bit - reserve room for attribute on the skb and align it
   * @skb: socket buffer to reserve room on
   * @attrtype: attribute type
   * @attrlen: length of attribute payload

   * @padattr: attribute type for the padding

   *
   * Adds a netlink attribute header to a socket buffer and reserves
   * room for the payload but does not copy it. It also ensure that this

   * attribute will have a 64-bit aligned nla_data() area.

   *
   * Returns NULL if the tailroom of the skb is insufficient to store
   * the attribute header and payload.
   */
  struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
  				 int padattr)
  {
  	size_t len;
  
  	if (nla_need_padding_for_64bit(skb))
  		len = nla_total_size_64bit(attrlen);
  	else
  		len = nla_total_size(attrlen);
  	if (unlikely(skb_tailroom(skb) < len))
  		return NULL;
  
  	return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
  }
  EXPORT_SYMBOL(nla_reserve_64bit);
  
  /**

   * nla_reserve_nohdr - reserve room for attribute without header

   * @skb: socket buffer to reserve room on

   * @attrlen: length of attribute payload

   *
   * Reserves room for attribute payload without a header.
   *
   * Returns NULL if the tailroom of the skb is insufficient to store
   * the attribute payload.
   */
  void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
  {
  	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
  		return NULL;
  
  	return __nla_reserve_nohdr(skb, attrlen);
  }

  EXPORT_SYMBOL(nla_reserve_nohdr);

  
  /**

   * __nla_put - Add a netlink attribute to a socket buffer
   * @skb: socket buffer to add attribute to
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   * @data: head of attribute payload
   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the attribute header and payload.
   */
  void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
  			     const void *data)
  {
  	struct nlattr *nla;
  
  	nla = __nla_reserve(skb, attrtype, attrlen);
  	memcpy(nla_data(nla), data, attrlen);
  }

  EXPORT_SYMBOL(__nla_put);

  /**

   * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
   * @skb: socket buffer to add attribute to
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   * @data: head of attribute payload

   * @padattr: attribute type for the padding

   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the attribute header and payload.
   */
  void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
  		     const void *data, int padattr)
  {
  	struct nlattr *nla;
  
  	nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
  	memcpy(nla_data(nla), data, attrlen);
  }
  EXPORT_SYMBOL(__nla_put_64bit);
  
  /**

   * __nla_put_nohdr - Add a netlink attribute without header
   * @skb: socket buffer to add attribute to
   * @attrlen: length of attribute payload
   * @data: head of attribute payload
   *
   * The caller is responsible to ensure that the skb provides enough
   * tailroom for the attribute payload.
   */
  void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
  {
  	void *start;
  
  	start = __nla_reserve_nohdr(skb, attrlen);
  	memcpy(start, data, attrlen);
  }

  EXPORT_SYMBOL(__nla_put_nohdr);

  
  /**
   * nla_put - Add a netlink attribute to a socket buffer
   * @skb: socket buffer to add attribute to
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   * @data: head of attribute payload
   *

   * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store

   * the attribute header and payload.
   */
  int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
  {
  	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))

  		return -EMSGSIZE;

  
  	__nla_put(skb, attrtype, attrlen, data);
  	return 0;
  }

  EXPORT_SYMBOL(nla_put);

  /**

   * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
   * @skb: socket buffer to add attribute to
   * @attrtype: attribute type
   * @attrlen: length of attribute payload
   * @data: head of attribute payload

   * @padattr: attribute type for the padding

   *
   * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
   * the attribute header and payload.
   */
  int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
  		  const void *data, int padattr)
  {
  	size_t len;
  
  	if (nla_need_padding_for_64bit(skb))
  		len = nla_total_size_64bit(attrlen);
  	else
  		len = nla_total_size(attrlen);
  	if (unlikely(skb_tailroom(skb) < len))
  		return -EMSGSIZE;
  
  	__nla_put_64bit(skb, attrtype, attrlen, data, padattr);
  	return 0;
  }
  EXPORT_SYMBOL(nla_put_64bit);
  
  /**

   * nla_put_nohdr - Add a netlink attribute without header
   * @skb: socket buffer to add attribute to
   * @attrlen: length of attribute payload
   * @data: head of attribute payload
   *

   * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store

   * the attribute payload.
   */
  int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
  {
  	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))

  		return -EMSGSIZE;

  
  	__nla_put_nohdr(skb, attrlen, data);
  	return 0;
  }

  EXPORT_SYMBOL(nla_put_nohdr);

  /**
   * nla_append - Add a netlink attribute without header or padding
   * @skb: socket buffer to add attribute to
   * @attrlen: length of attribute payload
   * @data: head of attribute payload
   *

   * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store

   * the attribute payload.
   */
  int nla_append(struct sk_buff *skb, int attrlen, const void *data)
  {
  	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))

  		return -EMSGSIZE;

  	skb_put_data(skb, data, attrlen);

  	return 0;
  }

  EXPORT_SYMBOL(nla_append);
  #endif