[linux.git] / lib / nlattr.c

/*
 * NETLINK      Netlink attributes
 *
 * 		Authors:	Thomas Graf <[email protected]>
 * 				Alexey Kuznetsov <[email protected]>
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/jiffies.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/types.h>
#include <net/netlink.h>

static const u16 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),
};

static int validate_nla(const struct nlattr *nla, int maxtype,
			const struct nla_policy *policy)
{
	const struct nla_policy *pt;
	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);

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

	pt = &policy[type];

	BUG_ON(pt->type > NLA_TYPE_MAX);

	switch (pt->type) {
	case NLA_FLAG:
		if (attrlen > 0)
			return -ERANGE;
		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)
			return -EINVAL;
		/* fall through */

	case NLA_STRING:
		if (attrlen < 1)
			return -ERANGE;

		if (pt->len) {
			char *buf = nla_data(nla);

			if (buf[attrlen - 1] == '\0')
				attrlen--;

			if (attrlen > pt->len)
				return -ERANGE;
		}
		break;

	case NLA_BINARY:
		if (pt->len && attrlen > pt->len)
			return -ERANGE;
		break;

	case NLA_NESTED_COMPAT:
		if (attrlen < pt->len)
			return -ERANGE;
		if (attrlen < NLA_ALIGN(pt->len))
			break;
		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
			return -ERANGE;
		nla = nla_data(nla) + NLA_ALIGN(pt->len);
		if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
			return -ERANGE;
		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;
	default:
		if (pt->len)
			minlen = pt->len;
		else if (pt->type != NLA_UNSPEC)
			minlen = nla_attr_minlen[pt->type];

		if (attrlen < minlen)
			return -ERANGE;
	}

	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
 *
 * Validates all attributes in the specified attribute stream against the
 * specified policy. Attributes with a type exceeding maxtype will be
 * ignored. 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)
{
	const struct nlattr *nla;
	int rem, err;

	nla_for_each_attr(nla, head, len, rem) {
		err = validate_nla(nla, maxtype, policy);
		if (err < 0)
			goto errout;
	}

	err = 0;
errout:
	return err;
}
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_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
 *
 * Parses a stream of attributes and stores a pointer to each attribute in
 * the tb array accessible via the attribute type. Attributes with a type
 * exceeding maxtype will be silently ignored for backwards compatibility
 * reasons. policy may be set to NULL if no validation is required.
 *
 * 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)
{
	const struct nlattr *nla;
	int rem, err;

	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 (policy) {
				err = validate_nla(nla, maxtype, policy);
				if (err < 0)
					goto errout;
			}

			tb[type] = (struct nlattr *)nla;
		}
	}

	if (unlikely(rem > 0))
		pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
				    rem, current->comm);

	err = 0;
errout:
	return err;
}
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_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);

	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 = (struct nlattr *) 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_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)
{
	void *start;

	start = skb_put(skb, NLA_ALIGN(attrlen));
	memset(start, 0, NLA_ALIGN(attrlen));

	return start;
}
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_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_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_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;

	memcpy(skb_put(skb, attrlen), data, attrlen);
	return 0;
}
EXPORT_SYMBOL(nla_append);
#endif
Commit	Line	Data
bfa83a9e TG	1	/*
	2	* NETLINK Netlink attributes
	3	*
	4	* Authors: Thomas Graf <[email protected]>
	5	* Alexey Kuznetsov <[email protected]>
	6	*/
	7
8bc3bcc9	8	#include <linux/export.h>
bfa83a9e TG	9	#include <linux/kernel.h>
	10	#include <linux/errno.h>
	11	#include <linux/jiffies.h>
	12	#include <linux/netdevice.h>
	13	#include <linux/skbuff.h>
	14	#include <linux/string.h>
	15	#include <linux/types.h>
	16	#include <net/netlink.h>
	17
3654654f	18	static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
bfa83a9e TG	19	[NLA_U8] = sizeof(u8),
	20	[NLA_U16] = sizeof(u16),
	21	[NLA_U32] = sizeof(u32),
	22	[NLA_U64] = sizeof(u64),
c30bc947	23	[NLA_MSECS] = sizeof(u64),
bfa83a9e	24	[NLA_NESTED] = NLA_HDRLEN,
9eca2eb9 JA	25	[NLA_S8] = sizeof(s8),
	26	[NLA_S16] = sizeof(s16),
	27	[NLA_S32] = sizeof(s32),
	28	[NLA_S64] = sizeof(s64),
bfa83a9e TG	29	};
bfa83a9e TG	30
3654654f	31	static int validate_nla(const struct nlattr *nla, int maxtype,
ef7c79ed	32	const struct nla_policy *policy)
bfa83a9e	33	{
ef7c79ed	34	const struct nla_policy *pt;
8f4c1f9b	35	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
bfa83a9e	36
8f4c1f9b	37	if (type <= 0 \|\| type > maxtype)
bfa83a9e TG	38	return 0;
bfa83a9e TG	39
8f4c1f9b	40	pt = &policy[type];
bfa83a9e TG	41
	42	BUG_ON(pt->type > NLA_TYPE_MAX);
	43
a5531a5d TG	44	switch (pt->type) {
	45	case NLA_FLAG:
	46	if (attrlen > 0)
	47	return -ERANGE;
	48	break;
bfa83a9e	49
a5531a5d TG	50	case NLA_NUL_STRING:
	51	if (pt->len)
	52	minlen = min_t(int, attrlen, pt->len + 1);
	53	else
	54	minlen = attrlen;
bfa83a9e	55
a5531a5d TG	56	if (!minlen \|\| memchr(nla_data(nla), '\0', minlen) == NULL)
	57	return -EINVAL;
	58	/* fall through */
	59
	60	case NLA_STRING:
	61	if (attrlen < 1)
	62	return -ERANGE;
	63
	64	if (pt->len) {
	65	char *buf = nla_data(nla);
	66
	67	if (buf[attrlen - 1] == '\0')
	68	attrlen--;
	69
	70	if (attrlen > pt->len)
	71	return -ERANGE;
	72	}
	73	break;
	74
d30045a0 JB	75	case NLA_BINARY:
	76	if (pt->len && attrlen > pt->len)
	77	return -ERANGE;
	78	break;
	79
1092cb21 PM	80	case NLA_NESTED_COMPAT:
	81	if (attrlen < pt->len)
	82	return -ERANGE;
	83	if (attrlen < NLA_ALIGN(pt->len))
	84	break;
	85	if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
	86	return -ERANGE;
	87	nla = nla_data(nla) + NLA_ALIGN(pt->len);
	88	if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
	89	return -ERANGE;
	90	break;
ea5693cc PM	91	case NLA_NESTED:
	92	/* a nested attributes is allowed to be empty; if its not,
	93	* it must have a size of at least NLA_HDRLEN.
	94	*/
	95	if (attrlen == 0)
	96	break;
a5531a5d TG	97	default:
	98	if (pt->len)
	99	minlen = pt->len;
	100	else if (pt->type != NLA_UNSPEC)
	101	minlen = nla_attr_minlen[pt->type];
	102
	103	if (attrlen < minlen)
	104	return -ERANGE;
	105	}
bfa83a9e TG	106
	107	return 0;
	108	}
	109
	110	/**
	111	* nla_validate - Validate a stream of attributes
	112	* @head: head of attribute stream
	113	* @len: length of attribute stream
	114	* @maxtype: maximum attribute type to be expected
	115	* @policy: validation policy
	116	*
	117	* Validates all attributes in the specified attribute stream against the
	118	* specified policy. Attributes with a type exceeding maxtype will be
	119	* ignored. See documenation of struct nla_policy for more details.
	120	*
	121	* Returns 0 on success or a negative error code.
	122	*/
3654654f	123	int nla_validate(const struct nlattr *head, int len, int maxtype,
ef7c79ed	124	const struct nla_policy *policy)
bfa83a9e	125	{
3654654f	126	const struct nlattr *nla;
bfa83a9e TG	127	int rem, err;
	128
	129	nla_for_each_attr(nla, head, len, rem) {
	130	err = validate_nla(nla, maxtype, policy);
	131	if (err < 0)
	132	goto errout;
	133	}
	134
	135	err = 0;
	136	errout:
	137	return err;
	138	}
6d6a138f	139	EXPORT_SYMBOL(nla_validate);
bfa83a9e	140
e487eb99 HE	141	/**
	142	* nla_policy_len - Determin the max. length of a policy
	143	* @policy: policy to use
	144	* @n: number of policies
	145	*
	146	* Determines the max. length of the policy. It is currently used
	147	* to allocated Netlink buffers roughly the size of the actual
	148	* message.
	149	*
	150	* Returns 0 on success or a negative error code.
	151	*/
	152	int
	153	nla_policy_len(const struct nla_policy *p, int n)
	154	{
	155	int i, len = 0;
	156
e3fa3aff	157	for (i = 0; i < n; i++, p++) {
e487eb99 HE	158	if (p->len)
	159	len += nla_total_size(p->len);
	160	else if (nla_attr_minlen[p->type])
	161	len += nla_total_size(nla_attr_minlen[p->type]);
	162	}
	163
	164	return len;
	165	}
6d6a138f	166	EXPORT_SYMBOL(nla_policy_len);
e487eb99	167
bfa83a9e TG	168	/**
	169	* nla_parse - Parse a stream of attributes into a tb buffer
	170	* @tb: destination array with maxtype+1 elements
	171	* @maxtype: maximum attribute type to be expected
	172	* @head: head of attribute stream
	173	* @len: length of attribute stream
10b595af	174	* @policy: validation policy
bfa83a9e TG	175	*
bfa83a9e TG	176	* Parses a stream of attributes and stores a pointer to each attribute in
b595076a	177	* the tb array accessible via the attribute type. Attributes with a type
bfa83a9e TG	178	* exceeding maxtype will be silently ignored for backwards compatibility
	179	* reasons. policy may be set to NULL if no validation is required.
	180	*
	181	* Returns 0 on success or a negative error code.
	182	*/
3654654f JE	183	int nla_parse(struct nlattr *tb, int maxtype, const struct nlattr head,
3654654f JE	184	int len, const struct nla_policy *policy)
bfa83a9e	185	{
3654654f	186	const struct nlattr *nla;
bfa83a9e TG	187	int rem, err;
	188
	189	memset(tb, 0, sizeof(struct nlattr ) (maxtype + 1));
	190
	191	nla_for_each_attr(nla, head, len, rem) {
8f4c1f9b	192	u16 type = nla_type(nla);
bfa83a9e TG	193
	194	if (type > 0 && type <= maxtype) {
	195	if (policy) {
	196	err = validate_nla(nla, maxtype, policy);
	197	if (err < 0)
	198	goto errout;
	199	}
	200
3654654f	201	tb[type] = (struct nlattr *)nla;
bfa83a9e TG	202	}
	203	}
	204
	205	if (unlikely(rem > 0))
bfc5184b MS	206	pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
bfc5184b MS	207	rem, current->comm);
bfa83a9e TG	208
	209	err = 0;
	210	errout:
	211	return err;
	212	}
6d6a138f	213	EXPORT_SYMBOL(nla_parse);
bfa83a9e TG	214
	215	/**
	216	* nla_find - Find a specific attribute in a stream of attributes
	217	* @head: head of attribute stream
	218	* @len: length of attribute stream
	219	* @attrtype: type of attribute to look for
	220	*
	221	* Returns the first attribute in the stream matching the specified type.
	222	*/
3654654f	223	struct nlattr nla_find(const struct nlattr head, int len, int attrtype)
bfa83a9e	224	{
3654654f	225	const struct nlattr *nla;
bfa83a9e TG	226	int rem;
	227
	228	nla_for_each_attr(nla, head, len, rem)
8f4c1f9b	229	if (nla_type(nla) == attrtype)
3654654f	230	return (struct nlattr *)nla;
bfa83a9e TG	231
	232	return NULL;
	233	}
6d6a138f	234	EXPORT_SYMBOL(nla_find);
bfa83a9e TG	235
	236	/**
	237	* nla_strlcpy - Copy string attribute payload into a sized buffer
	238	* @dst: where to copy the string to
10b595af	239	* @nla: attribute to copy the string from
bfa83a9e TG	240	* @dstsize: size of destination buffer
	241	*
	242	* Copies at most dstsize - 1 bytes into the destination buffer.
	243	* The result is always a valid NUL-terminated string. Unlike
	244	* strlcpy the destination buffer is always padded out.
	245	*
	246	* Returns the length of the source buffer.
	247	*/
	248	size_t nla_strlcpy(char dst, const struct nlattr nla, size_t dstsize)
	249	{
	250	size_t srclen = nla_len(nla);
	251	char *src = nla_data(nla);
	252
	253	if (srclen > 0 && src[srclen - 1] == '\0')
	254	srclen--;
	255
	256	if (dstsize > 0) {
	257	size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
	258
	259	memset(dst, 0, dstsize);
	260	memcpy(dst, src, len);
	261	}
	262
	263	return srclen;
	264	}
6d6a138f	265	EXPORT_SYMBOL(nla_strlcpy);
bfa83a9e TG	266
	267	/**
	268	* nla_memcpy - Copy a netlink attribute into another memory area
	269	* @dest: where to copy to memcpy
	270	* @src: netlink attribute to copy from
	271	* @count: size of the destination area
	272	*
	273	* Note: The number of bytes copied is limited by the length of
	274	* attribute's payload. memcpy
	275	*
	276	* Returns the number of bytes copied.
	277	*/
b057efd4	278	int nla_memcpy(void dest, const struct nlattr src, int count)
bfa83a9e TG	279	{
	280	int minlen = min_t(int, count, nla_len(src));
	281
	282	memcpy(dest, nla_data(src), minlen);
	283
	284	return minlen;
	285	}
6d6a138f	286	EXPORT_SYMBOL(nla_memcpy);
bfa83a9e TG	287
	288	/**
	289	* nla_memcmp - Compare an attribute with sized memory area
	290	* @nla: netlink attribute
	291	* @data: memory area
	292	* @size: size of memory area
	293	*/
	294	int nla_memcmp(const struct nlattr nla, const void data,
	295	size_t size)
	296	{
	297	int d = nla_len(nla) - size;
	298
	299	if (d == 0)
	300	d = memcmp(nla_data(nla), data, size);
	301
	302	return d;
	303	}
6d6a138f	304	EXPORT_SYMBOL(nla_memcmp);
bfa83a9e TG	305
	306	/**
	307	* nla_strcmp - Compare a string attribute against a string
	308	* @nla: netlink string attribute
	309	* @str: another string
	310	*/
	311	int nla_strcmp(const struct nlattr nla, const char str)
	312	{
8b7b9324 PN	313	int len = strlen(str);
	314	char *buf = nla_data(nla);
	315	int attrlen = nla_len(nla);
	316	int d;
bfa83a9e	317
8b7b9324 PN	318	if (attrlen > 0 && buf[attrlen - 1] == '\0')
	319	attrlen--;
	320
	321	d = attrlen - len;
bfa83a9e TG	322	if (d == 0)
	323	d = memcmp(nla_data(nla), str, len);
	324
	325	return d;
	326	}
6d6a138f	327	EXPORT_SYMBOL(nla_strcmp);
bfa83a9e	328
90800216	329	#ifdef CONFIG_NET
bfa83a9e TG	330	/**
	331	* __nla_reserve - reserve room for attribute on the skb
	332	* @skb: socket buffer to reserve room on
	333	* @attrtype: attribute type
	334	* @attrlen: length of attribute payload
	335	*
	336	* Adds a netlink attribute header to a socket buffer and reserves
	337	* room for the payload but does not copy it.
	338	*
	339	* The caller is responsible to ensure that the skb provides enough
	340	* tailroom for the attribute header and payload.
	341	*/
	342	struct nlattr __nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	343	{
	344	struct nlattr *nla;
	345
	346	nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
	347	nla->nla_type = attrtype;
	348	nla->nla_len = nla_attr_size(attrlen);
	349
	350	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
	351
	352	return nla;
	353	}
90800216	354	EXPORT_SYMBOL(__nla_reserve);
bfa83a9e	355
fe4944e5 TG	356	/**
	357	* __nla_reserve_nohdr - reserve room for attribute without header
	358	* @skb: socket buffer to reserve room on
	359	* @attrlen: length of attribute payload
	360	*
	361	* Reserves room for attribute payload without a header.
	362	*
	363	* The caller is responsible to ensure that the skb provides enough
	364	* tailroom for the payload.
	365	*/
	366	void __nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	367	{
	368	void *start;
	369
	370	start = skb_put(skb, NLA_ALIGN(attrlen));
	371	memset(start, 0, NLA_ALIGN(attrlen));
	372
	373	return start;
	374	}
90800216	375	EXPORT_SYMBOL(__nla_reserve_nohdr);
fe4944e5	376
bfa83a9e TG	377	/**
	378	* nla_reserve - reserve room for attribute on the skb
	379	* @skb: socket buffer to reserve room on
	380	* @attrtype: attribute type
	381	* @attrlen: length of attribute payload
	382	*
	383	* Adds a netlink attribute header to a socket buffer and reserves
	384	* room for the payload but does not copy it.
	385	*
	386	* Returns NULL if the tailroom of the skb is insufficient to store
	387	* the attribute header and payload.
	388	*/
	389	struct nlattr nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	390	{
	391	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
	392	return NULL;
	393
	394	return __nla_reserve(skb, attrtype, attrlen);
	395	}
90800216	396	EXPORT_SYMBOL(nla_reserve);
bfa83a9e	397
fe4944e5	398	/**
10b595af	399	* nla_reserve_nohdr - reserve room for attribute without header
fe4944e5	400	* @skb: socket buffer to reserve room on
10b595af	401	* @attrlen: length of attribute payload
fe4944e5 TG	402	*
	403	* Reserves room for attribute payload without a header.
	404	*
	405	* Returns NULL if the tailroom of the skb is insufficient to store
	406	* the attribute payload.
	407	*/
	408	void nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	409	{
	410	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
	411	return NULL;
	412
	413	return __nla_reserve_nohdr(skb, attrlen);
	414	}
90800216	415	EXPORT_SYMBOL(nla_reserve_nohdr);
fe4944e5	416
bfa83a9e TG	417	/**
	418	* __nla_put - Add a netlink attribute to a socket buffer
	419	* @skb: socket buffer to add attribute to
	420	* @attrtype: attribute type
	421	* @attrlen: length of attribute payload
	422	* @data: head of attribute payload
	423	*
	424	* The caller is responsible to ensure that the skb provides enough
	425	* tailroom for the attribute header and payload.
	426	*/
	427	void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
	428	const void *data)
	429	{
	430	struct nlattr *nla;
	431
	432	nla = __nla_reserve(skb, attrtype, attrlen);
	433	memcpy(nla_data(nla), data, attrlen);
	434	}
90800216	435	EXPORT_SYMBOL(__nla_put);
bfa83a9e	436
fe4944e5 TG	437	/**
	438	* __nla_put_nohdr - Add a netlink attribute without header
	439	* @skb: socket buffer to add attribute to
	440	* @attrlen: length of attribute payload
	441	* @data: head of attribute payload
	442	*
	443	* The caller is responsible to ensure that the skb provides enough
	444	* tailroom for the attribute payload.
	445	*/
	446	void __nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	447	{
	448	void *start;
	449
	450	start = __nla_reserve_nohdr(skb, attrlen);
	451	memcpy(start, data, attrlen);
	452	}
90800216	453	EXPORT_SYMBOL(__nla_put_nohdr);
bfa83a9e TG	454
	455	/**
	456	* nla_put - Add a netlink attribute to a socket buffer
	457	* @skb: socket buffer to add attribute to
	458	* @attrtype: attribute type
	459	* @attrlen: length of attribute payload
	460	* @data: head of attribute payload
	461	*
bc3ed28c	462	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
bfa83a9e TG	463	* the attribute header and payload.
	464	*/
	465	int nla_put(struct sk_buff skb, int attrtype, int attrlen, const void data)
	466	{
	467	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
bc3ed28c	468	return -EMSGSIZE;
bfa83a9e TG	469
	470	__nla_put(skb, attrtype, attrlen, data);
	471	return 0;
	472	}
90800216	473	EXPORT_SYMBOL(nla_put);
bfa83a9e	474
fe4944e5 TG	475	/**
	476	* nla_put_nohdr - Add a netlink attribute without header
	477	* @skb: socket buffer to add attribute to
	478	* @attrlen: length of attribute payload
	479	* @data: head of attribute payload
	480	*
bc3ed28c	481	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
fe4944e5 TG	482	* the attribute payload.
	483	*/
	484	int nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	485	{
	486	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	487	return -EMSGSIZE;
fe4944e5 TG	488
	489	__nla_put_nohdr(skb, attrlen, data);
	490	return 0;
	491	}
90800216	492	EXPORT_SYMBOL(nla_put_nohdr);
bfa83a9e	493
01480e1c PM	494	/**
	495	* nla_append - Add a netlink attribute without header or padding
	496	* @skb: socket buffer to add attribute to
	497	* @attrlen: length of attribute payload
	498	* @data: head of attribute payload
	499	*
bc3ed28c	500	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
01480e1c PM	501	* the attribute payload.
	502	*/
	503	int nla_append(struct sk_buff skb, int attrlen, const void data)
	504	{
	505	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	506	return -EMSGSIZE;
01480e1c PM	507
	508	memcpy(skb_put(skb, attrlen), data, attrlen);
	509	return 0;
	510	}
90800216 HX	511	EXPORT_SYMBOL(nla_append);
90800216 HX	512	#endif