[deliverable/linux.git] / lib / nlattr.c

/*
 * 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>

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);
	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 = (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 <tgraf@suug.ch>
	5	* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
	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>
bfa83a9e TG	12	#include <linux/skbuff.h>
	13	#include <linux/string.h>
	14	#include <linux/types.h>
	15	#include <net/netlink.h>
	16
3654654f	17	static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {
bfa83a9e TG	18	[NLA_U8] = sizeof(u8),
	19	[NLA_U16] = sizeof(u16),
	20	[NLA_U32] = sizeof(u32),
	21	[NLA_U64] = sizeof(u64),
c30bc947	22	[NLA_MSECS] = sizeof(u64),
bfa83a9e	23	[NLA_NESTED] = NLA_HDRLEN,
9eca2eb9 JA	24	[NLA_S8] = sizeof(s8),
	25	[NLA_S16] = sizeof(s16),
	26	[NLA_S32] = sizeof(s32),
	27	[NLA_S64] = sizeof(s64),
bfa83a9e TG	28	};
bfa83a9e TG	29
3654654f	30	static int validate_nla(const struct nlattr *nla, int maxtype,
ef7c79ed	31	const struct nla_policy *policy)
bfa83a9e	32	{
ef7c79ed	33	const struct nla_policy *pt;
8f4c1f9b	34	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
bfa83a9e	35
8f4c1f9b	36	if (type <= 0 \|\| type > maxtype)
bfa83a9e TG	37	return 0;
bfa83a9e TG	38
8f4c1f9b	39	pt = &policy[type];
bfa83a9e TG	40
	41	BUG_ON(pt->type > NLA_TYPE_MAX);
	42
a5531a5d TG	43	switch (pt->type) {
	44	case NLA_FLAG:
	45	if (attrlen > 0)
	46	return -ERANGE;
	47	break;
bfa83a9e	48
a5531a5d TG	49	case NLA_NUL_STRING:
	50	if (pt->len)
	51	minlen = min_t(int, attrlen, pt->len + 1);
	52	else
	53	minlen = attrlen;
bfa83a9e	54
a5531a5d TG	55	if (!minlen \|\| memchr(nla_data(nla), '\0', minlen) == NULL)
	56	return -EINVAL;
	57	/* fall through */
	58
	59	case NLA_STRING:
	60	if (attrlen < 1)
	61	return -ERANGE;
	62
	63	if (pt->len) {
	64	char *buf = nla_data(nla);
	65
	66	if (buf[attrlen - 1] == '\0')
	67	attrlen--;
	68
	69	if (attrlen > pt->len)
	70	return -ERANGE;
	71	}
	72	break;
	73
d30045a0 JB	74	case NLA_BINARY:
	75	if (pt->len && attrlen > pt->len)
	76	return -ERANGE;
	77	break;
	78
1092cb21 PM	79	case NLA_NESTED_COMPAT:
	80	if (attrlen < pt->len)
	81	return -ERANGE;
	82	if (attrlen < NLA_ALIGN(pt->len))
	83	break;
	84	if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
	85	return -ERANGE;
	86	nla = nla_data(nla) + NLA_ALIGN(pt->len);
	87	if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
	88	return -ERANGE;
	89	break;
ea5693cc PM	90	case NLA_NESTED:
	91	/* a nested attributes is allowed to be empty; if its not,
	92	* it must have a size of at least NLA_HDRLEN.
	93	*/
	94	if (attrlen == 0)
	95	break;
a5531a5d TG	96	default:
	97	if (pt->len)
	98	minlen = pt->len;
	99	else if (pt->type != NLA_UNSPEC)
	100	minlen = nla_attr_minlen[pt->type];
	101
	102	if (attrlen < minlen)
	103	return -ERANGE;
	104	}
bfa83a9e TG	105
	106	return 0;
	107	}
	108
	109	/**
	110	* nla_validate - Validate a stream of attributes
	111	* @head: head of attribute stream
	112	* @len: length of attribute stream
	113	* @maxtype: maximum attribute type to be expected
	114	* @policy: validation policy
	115	*
	116	* Validates all attributes in the specified attribute stream against the
	117	* specified policy. Attributes with a type exceeding maxtype will be
	118	* ignored. See documenation of struct nla_policy for more details.
	119	*
	120	* Returns 0 on success or a negative error code.
	121	*/
3654654f	122	int nla_validate(const struct nlattr *head, int len, int maxtype,
ef7c79ed	123	const struct nla_policy *policy)
bfa83a9e	124	{
3654654f	125	const struct nlattr *nla;
bfa83a9e TG	126	int rem, err;
	127
	128	nla_for_each_attr(nla, head, len, rem) {
	129	err = validate_nla(nla, maxtype, policy);
	130	if (err < 0)
	131	goto errout;
	132	}
	133
	134	err = 0;
	135	errout:
	136	return err;
	137	}
6d6a138f	138	EXPORT_SYMBOL(nla_validate);
bfa83a9e	139
e487eb99 HE	140	/**
	141	* nla_policy_len - Determin the max. length of a policy
	142	* @policy: policy to use
	143	* @n: number of policies
	144	*
	145	* Determines the max. length of the policy. It is currently used
	146	* to allocated Netlink buffers roughly the size of the actual
	147	* message.
	148	*
	149	* Returns 0 on success or a negative error code.
	150	*/
	151	int
	152	nla_policy_len(const struct nla_policy *p, int n)
	153	{
	154	int i, len = 0;
	155
e3fa3aff	156	for (i = 0; i < n; i++, p++) {
e487eb99 HE	157	if (p->len)
	158	len += nla_total_size(p->len);
	159	else if (nla_attr_minlen[p->type])
	160	len += nla_total_size(nla_attr_minlen[p->type]);
	161	}
	162
	163	return len;
	164	}
6d6a138f	165	EXPORT_SYMBOL(nla_policy_len);
e487eb99	166
bfa83a9e TG	167	/**
	168	* nla_parse - Parse a stream of attributes into a tb buffer
	169	* @tb: destination array with maxtype+1 elements
	170	* @maxtype: maximum attribute type to be expected
	171	* @head: head of attribute stream
	172	* @len: length of attribute stream
10b595af	173	* @policy: validation policy
bfa83a9e TG	174	*
bfa83a9e TG	175	* Parses a stream of attributes and stores a pointer to each attribute in
b595076a	176	* the tb array accessible via the attribute type. Attributes with a type
bfa83a9e TG	177	* exceeding maxtype will be silently ignored for backwards compatibility
	178	* reasons. policy may be set to NULL if no validation is required.
	179	*
	180	* Returns 0 on success or a negative error code.
	181	*/
3654654f JE	182	int nla_parse(struct nlattr *tb, int maxtype, const struct nlattr head,
3654654f JE	183	int len, const struct nla_policy *policy)
bfa83a9e	184	{
3654654f	185	const struct nlattr *nla;
bfa83a9e TG	186	int rem, err;
	187
	188	memset(tb, 0, sizeof(struct nlattr ) (maxtype + 1));
	189
	190	nla_for_each_attr(nla, head, len, rem) {
8f4c1f9b	191	u16 type = nla_type(nla);
bfa83a9e TG	192
	193	if (type > 0 && type <= maxtype) {
	194	if (policy) {
	195	err = validate_nla(nla, maxtype, policy);
	196	if (err < 0)
	197	goto errout;
	198	}
	199
3654654f	200	tb[type] = (struct nlattr *)nla;
bfa83a9e TG	201	}
	202	}
	203
	204	if (unlikely(rem > 0))
bfc5184b MS	205	pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
bfc5184b MS	206	rem, current->comm);
bfa83a9e TG	207
	208	err = 0;
	209	errout:
	210	return err;
	211	}
6d6a138f	212	EXPORT_SYMBOL(nla_parse);
bfa83a9e TG	213
	214	/**
	215	* nla_find - Find a specific attribute in a stream of attributes
	216	* @head: head of attribute stream
	217	* @len: length of attribute stream
	218	* @attrtype: type of attribute to look for
	219	*
	220	* Returns the first attribute in the stream matching the specified type.
	221	*/
3654654f	222	struct nlattr nla_find(const struct nlattr head, int len, int attrtype)
bfa83a9e	223	{
3654654f	224	const struct nlattr *nla;
bfa83a9e TG	225	int rem;
	226
	227	nla_for_each_attr(nla, head, len, rem)
8f4c1f9b	228	if (nla_type(nla) == attrtype)
3654654f	229	return (struct nlattr *)nla;
bfa83a9e TG	230
	231	return NULL;
	232	}
6d6a138f	233	EXPORT_SYMBOL(nla_find);
bfa83a9e TG	234
	235	/**
	236	* nla_strlcpy - Copy string attribute payload into a sized buffer
	237	* @dst: where to copy the string to
10b595af	238	* @nla: attribute to copy the string from
bfa83a9e TG	239	* @dstsize: size of destination buffer
	240	*
	241	* Copies at most dstsize - 1 bytes into the destination buffer.
	242	* The result is always a valid NUL-terminated string. Unlike
	243	* strlcpy the destination buffer is always padded out.
	244	*
	245	* Returns the length of the source buffer.
	246	*/
	247	size_t nla_strlcpy(char dst, const struct nlattr nla, size_t dstsize)
	248	{
	249	size_t srclen = nla_len(nla);
	250	char *src = nla_data(nla);
	251
	252	if (srclen > 0 && src[srclen - 1] == '\0')
	253	srclen--;
	254
	255	if (dstsize > 0) {
	256	size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
	257
	258	memset(dst, 0, dstsize);
	259	memcpy(dst, src, len);
	260	}
	261
	262	return srclen;
	263	}
6d6a138f	264	EXPORT_SYMBOL(nla_strlcpy);
bfa83a9e TG	265
	266	/**
	267	* nla_memcpy - Copy a netlink attribute into another memory area
	268	* @dest: where to copy to memcpy
	269	* @src: netlink attribute to copy from
	270	* @count: size of the destination area
	271	*
	272	* Note: The number of bytes copied is limited by the length of
	273	* attribute's payload. memcpy
	274	*
	275	* Returns the number of bytes copied.
	276	*/
b057efd4	277	int nla_memcpy(void dest, const struct nlattr src, int count)
bfa83a9e TG	278	{
	279	int minlen = min_t(int, count, nla_len(src));
	280
	281	memcpy(dest, nla_data(src), minlen);
5899f047 JB	282	if (count > minlen)
5899f047 JB	283	memset(dest + minlen, 0, count - minlen);
bfa83a9e TG	284
	285	return minlen;
	286	}
6d6a138f	287	EXPORT_SYMBOL(nla_memcpy);
bfa83a9e TG	288
	289	/**
	290	* nla_memcmp - Compare an attribute with sized memory area
	291	* @nla: netlink attribute
	292	* @data: memory area
	293	* @size: size of memory area
	294	*/
	295	int nla_memcmp(const struct nlattr nla, const void data,
	296	size_t size)
	297	{
	298	int d = nla_len(nla) - size;
	299
	300	if (d == 0)
	301	d = memcmp(nla_data(nla), data, size);
	302
	303	return d;
	304	}
6d6a138f	305	EXPORT_SYMBOL(nla_memcmp);
bfa83a9e TG	306
	307	/**
	308	* nla_strcmp - Compare a string attribute against a string
	309	* @nla: netlink string attribute
	310	* @str: another string
	311	*/
	312	int nla_strcmp(const struct nlattr nla, const char str)
	313	{
8b7b9324 PN	314	int len = strlen(str);
	315	char *buf = nla_data(nla);
	316	int attrlen = nla_len(nla);
	317	int d;
bfa83a9e	318
8b7b9324 PN	319	if (attrlen > 0 && buf[attrlen - 1] == '\0')
	320	attrlen--;
	321
	322	d = attrlen - len;
bfa83a9e TG	323	if (d == 0)
	324	d = memcmp(nla_data(nla), str, len);
	325
	326	return d;
	327	}
6d6a138f	328	EXPORT_SYMBOL(nla_strcmp);
bfa83a9e	329
90800216	330	#ifdef CONFIG_NET
bfa83a9e TG	331	/**
	332	* __nla_reserve - reserve room for attribute on the skb
	333	* @skb: socket buffer to reserve room on
	334	* @attrtype: attribute type
	335	* @attrlen: length of attribute payload
	336	*
	337	* Adds a netlink attribute header to a socket buffer and reserves
	338	* room for the payload but does not copy it.
	339	*
	340	* The caller is responsible to ensure that the skb provides enough
	341	* tailroom for the attribute header and payload.
	342	*/
	343	struct nlattr __nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	344	{
	345	struct nlattr *nla;
	346
	347	nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
	348	nla->nla_type = attrtype;
	349	nla->nla_len = nla_attr_size(attrlen);
	350
	351	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
	352
	353	return nla;
	354	}
90800216	355	EXPORT_SYMBOL(__nla_reserve);
bfa83a9e	356
fe4944e5 TG	357	/**
	358	* __nla_reserve_nohdr - reserve room for attribute without header
	359	* @skb: socket buffer to reserve room on
	360	* @attrlen: length of attribute payload
	361	*
	362	* Reserves room for attribute payload without a header.
	363	*
	364	* The caller is responsible to ensure that the skb provides enough
	365	* tailroom for the payload.
	366	*/
	367	void __nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	368	{
	369	void *start;
	370
	371	start = skb_put(skb, NLA_ALIGN(attrlen));
	372	memset(start, 0, NLA_ALIGN(attrlen));
	373
	374	return start;
	375	}
90800216	376	EXPORT_SYMBOL(__nla_reserve_nohdr);
fe4944e5	377
bfa83a9e TG	378	/**
	379	* nla_reserve - reserve room for attribute on the skb
	380	* @skb: socket buffer to reserve room on
	381	* @attrtype: attribute type
	382	* @attrlen: length of attribute payload
	383	*
	384	* Adds a netlink attribute header to a socket buffer and reserves
	385	* room for the payload but does not copy it.
	386	*
	387	* Returns NULL if the tailroom of the skb is insufficient to store
	388	* the attribute header and payload.
	389	*/
	390	struct nlattr nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	391	{
	392	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
	393	return NULL;
	394
	395	return __nla_reserve(skb, attrtype, attrlen);
	396	}
90800216	397	EXPORT_SYMBOL(nla_reserve);
bfa83a9e	398
fe4944e5	399	/**
10b595af	400	* nla_reserve_nohdr - reserve room for attribute without header
fe4944e5	401	* @skb: socket buffer to reserve room on
10b595af	402	* @attrlen: length of attribute payload
fe4944e5 TG	403	*
	404	* Reserves room for attribute payload without a header.
	405	*
	406	* Returns NULL if the tailroom of the skb is insufficient to store
	407	* the attribute payload.
	408	*/
	409	void nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	410	{
	411	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
	412	return NULL;
	413
	414	return __nla_reserve_nohdr(skb, attrlen);
	415	}
90800216	416	EXPORT_SYMBOL(nla_reserve_nohdr);
fe4944e5	417
bfa83a9e TG	418	/**
	419	* __nla_put - Add a netlink attribute to a socket buffer
	420	* @skb: socket buffer to add attribute to
	421	* @attrtype: attribute type
	422	* @attrlen: length of attribute payload
	423	* @data: head of attribute payload
	424	*
	425	* The caller is responsible to ensure that the skb provides enough
	426	* tailroom for the attribute header and payload.
	427	*/
	428	void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
	429	const void *data)
	430	{
	431	struct nlattr *nla;
	432
	433	nla = __nla_reserve(skb, attrtype, attrlen);
	434	memcpy(nla_data(nla), data, attrlen);
	435	}
90800216	436	EXPORT_SYMBOL(__nla_put);
bfa83a9e	437
fe4944e5 TG	438	/**
	439	* __nla_put_nohdr - Add a netlink attribute without header
	440	* @skb: socket buffer to add attribute to
	441	* @attrlen: length of attribute payload
	442	* @data: head of attribute payload
	443	*
	444	* The caller is responsible to ensure that the skb provides enough
	445	* tailroom for the attribute payload.
	446	*/
	447	void __nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	448	{
	449	void *start;
	450
	451	start = __nla_reserve_nohdr(skb, attrlen);
	452	memcpy(start, data, attrlen);
	453	}
90800216	454	EXPORT_SYMBOL(__nla_put_nohdr);
bfa83a9e TG	455
	456	/**
	457	* nla_put - Add a netlink attribute to a socket buffer
	458	* @skb: socket buffer to add attribute to
	459	* @attrtype: attribute type
	460	* @attrlen: length of attribute payload
	461	* @data: head of attribute payload
	462	*
bc3ed28c	463	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
bfa83a9e TG	464	* the attribute header and payload.
	465	*/
	466	int nla_put(struct sk_buff skb, int attrtype, int attrlen, const void data)
	467	{
	468	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
bc3ed28c	469	return -EMSGSIZE;
bfa83a9e TG	470
	471	__nla_put(skb, attrtype, attrlen, data);
	472	return 0;
	473	}
90800216	474	EXPORT_SYMBOL(nla_put);
bfa83a9e	475
fe4944e5 TG	476	/**
	477	* nla_put_nohdr - Add a netlink attribute without header
	478	* @skb: socket buffer to add attribute to
	479	* @attrlen: length of attribute payload
	480	* @data: head of attribute payload
	481	*
bc3ed28c	482	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
fe4944e5 TG	483	* the attribute payload.
	484	*/
	485	int nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	486	{
	487	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	488	return -EMSGSIZE;
fe4944e5 TG	489
	490	__nla_put_nohdr(skb, attrlen, data);
	491	return 0;
	492	}
90800216	493	EXPORT_SYMBOL(nla_put_nohdr);
bfa83a9e	494
01480e1c PM	495	/**
	496	* nla_append - Add a netlink attribute without header or padding
	497	* @skb: socket buffer to add attribute to
	498	* @attrlen: length of attribute payload
	499	* @data: head of attribute payload
	500	*
bc3ed28c	501	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
01480e1c PM	502	* the attribute payload.
	503	*/
	504	int nla_append(struct sk_buff skb, int attrlen, const void data)
	505	{
	506	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	507	return -EMSGSIZE;
01480e1c PM	508
	509	memcpy(skb_put(skb, attrlen), data, attrlen);
	510	return 0;
	511	}
90800216 HX	512	EXPORT_SYMBOL(nla_append);
90800216 HX	513	#endif