[mirror_ubuntu-artful-kernel.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/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;
}

/**
 * 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;
}

/**
 * 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))
		printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
		       "attributes.\n", rem);

	err = 0;
errout:
	return err;
}

/**
 * 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;
}

/**
 * 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;
}

/**
 * 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;
}

/**
 * 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;
}

/**
 * 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) + 1;
	int d = nla_len(nla) - len;

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

	return d;
}

#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

EXPORT_SYMBOL(nla_validate);
EXPORT_SYMBOL(nla_policy_len);
EXPORT_SYMBOL(nla_parse);
EXPORT_SYMBOL(nla_find);
EXPORT_SYMBOL(nla_strlcpy);
EXPORT_SYMBOL(nla_memcpy);
EXPORT_SYMBOL(nla_memcmp);
EXPORT_SYMBOL(nla_strcmp);
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>
	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	}
	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	}
	165
bfa83a9e TG	166	/**
	167	* nla_parse - Parse a stream of attributes into a tb buffer
	168	* @tb: destination array with maxtype+1 elements
	169	* @maxtype: maximum attribute type to be expected
	170	* @head: head of attribute stream
	171	* @len: length of attribute stream
10b595af	172	* @policy: validation policy
bfa83a9e TG	173	*
bfa83a9e TG	174	* Parses a stream of attributes and stores a pointer to each attribute in
b595076a	175	* the tb array accessible via the attribute type. Attributes with a type
bfa83a9e TG	176	* exceeding maxtype will be silently ignored for backwards compatibility
	177	* reasons. policy may be set to NULL if no validation is required.
	178	*
	179	* Returns 0 on success or a negative error code.
	180	*/
3654654f JE	181	int nla_parse(struct nlattr *tb, int maxtype, const struct nlattr head,
3654654f JE	182	int len, const struct nla_policy *policy)
bfa83a9e	183	{
3654654f	184	const struct nlattr *nla;
bfa83a9e TG	185	int rem, err;
	186
	187	memset(tb, 0, sizeof(struct nlattr ) (maxtype + 1));
	188
	189	nla_for_each_attr(nla, head, len, rem) {
8f4c1f9b	190	u16 type = nla_type(nla);
bfa83a9e TG	191
	192	if (type > 0 && type <= maxtype) {
	193	if (policy) {
	194	err = validate_nla(nla, maxtype, policy);
	195	if (err < 0)
	196	goto errout;
	197	}
	198
3654654f	199	tb[type] = (struct nlattr *)nla;
bfa83a9e TG	200	}
	201	}
	202
	203	if (unlikely(rem > 0))
	204	printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
	205	"attributes.\n", rem);
	206
	207	err = 0;
	208	errout:
	209	return err;
	210	}
	211
	212	/**
	213	* nla_find - Find a specific attribute in a stream of attributes
	214	* @head: head of attribute stream
	215	* @len: length of attribute stream
	216	* @attrtype: type of attribute to look for
	217	*
	218	* Returns the first attribute in the stream matching the specified type.
	219	*/
3654654f	220	struct nlattr nla_find(const struct nlattr head, int len, int attrtype)
bfa83a9e	221	{
3654654f	222	const struct nlattr *nla;
bfa83a9e TG	223	int rem;
	224
	225	nla_for_each_attr(nla, head, len, rem)
8f4c1f9b	226	if (nla_type(nla) == attrtype)
3654654f	227	return (struct nlattr *)nla;
bfa83a9e TG	228
	229	return NULL;
	230	}
	231
	232	/**
	233	* nla_strlcpy - Copy string attribute payload into a sized buffer
	234	* @dst: where to copy the string to
10b595af	235	* @nla: attribute to copy the string from
bfa83a9e TG	236	* @dstsize: size of destination buffer
	237	*
	238	* Copies at most dstsize - 1 bytes into the destination buffer.
	239	* The result is always a valid NUL-terminated string. Unlike
	240	* strlcpy the destination buffer is always padded out.
	241	*
	242	* Returns the length of the source buffer.
	243	*/
	244	size_t nla_strlcpy(char dst, const struct nlattr nla, size_t dstsize)
	245	{
	246	size_t srclen = nla_len(nla);
	247	char *src = nla_data(nla);
	248
	249	if (srclen > 0 && src[srclen - 1] == '\0')
	250	srclen--;
	251
	252	if (dstsize > 0) {
	253	size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
	254
	255	memset(dst, 0, dstsize);
	256	memcpy(dst, src, len);
	257	}
	258
	259	return srclen;
	260	}
	261
	262	/**
	263	* nla_memcpy - Copy a netlink attribute into another memory area
	264	* @dest: where to copy to memcpy
	265	* @src: netlink attribute to copy from
	266	* @count: size of the destination area
	267	*
	268	* Note: The number of bytes copied is limited by the length of
	269	* attribute's payload. memcpy
	270	*
	271	* Returns the number of bytes copied.
	272	*/
b057efd4	273	int nla_memcpy(void dest, const struct nlattr src, int count)
bfa83a9e TG	274	{
	275	int minlen = min_t(int, count, nla_len(src));
	276
	277	memcpy(dest, nla_data(src), minlen);
	278
	279	return minlen;
	280	}
	281
	282	/**
	283	* nla_memcmp - Compare an attribute with sized memory area
	284	* @nla: netlink attribute
	285	* @data: memory area
	286	* @size: size of memory area
	287	*/
	288	int nla_memcmp(const struct nlattr nla, const void data,
	289	size_t size)
	290	{
	291	int d = nla_len(nla) - size;
	292
	293	if (d == 0)
	294	d = memcmp(nla_data(nla), data, size);
	295
	296	return d;
	297	}
	298
	299	/**
	300	* nla_strcmp - Compare a string attribute against a string
	301	* @nla: netlink string attribute
	302	* @str: another string
	303	*/
	304	int nla_strcmp(const struct nlattr nla, const char str)
	305	{
	306	int len = strlen(str) + 1;
	307	int d = nla_len(nla) - len;
	308
	309	if (d == 0)
	310	d = memcmp(nla_data(nla), str, len);
	311
	312	return d;
	313	}
	314
90800216	315	#ifdef CONFIG_NET
bfa83a9e TG	316	/**
	317	* __nla_reserve - reserve room for attribute on the skb
	318	* @skb: socket buffer to reserve room on
	319	* @attrtype: attribute type
	320	* @attrlen: length of attribute payload
	321	*
	322	* Adds a netlink attribute header to a socket buffer and reserves
	323	* room for the payload but does not copy it.
	324	*
	325	* The caller is responsible to ensure that the skb provides enough
	326	* tailroom for the attribute header and payload.
	327	*/
	328	struct nlattr __nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	329	{
	330	struct nlattr *nla;
	331
	332	nla = (struct nlattr *) skb_put(skb, nla_total_size(attrlen));
	333	nla->nla_type = attrtype;
	334	nla->nla_len = nla_attr_size(attrlen);
	335
	336	memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
	337
	338	return nla;
	339	}
90800216	340	EXPORT_SYMBOL(__nla_reserve);
bfa83a9e	341
fe4944e5 TG	342	/**
	343	* __nla_reserve_nohdr - reserve room for attribute without header
	344	* @skb: socket buffer to reserve room on
	345	* @attrlen: length of attribute payload
	346	*
	347	* Reserves room for attribute payload without a header.
	348	*
	349	* The caller is responsible to ensure that the skb provides enough
	350	* tailroom for the payload.
	351	*/
	352	void __nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	353	{
	354	void *start;
	355
	356	start = skb_put(skb, NLA_ALIGN(attrlen));
	357	memset(start, 0, NLA_ALIGN(attrlen));
	358
	359	return start;
	360	}
90800216	361	EXPORT_SYMBOL(__nla_reserve_nohdr);
fe4944e5	362
bfa83a9e TG	363	/**
	364	* nla_reserve - reserve room for attribute on the skb
	365	* @skb: socket buffer to reserve room on
	366	* @attrtype: attribute type
	367	* @attrlen: length of attribute payload
	368	*
	369	* Adds a netlink attribute header to a socket buffer and reserves
	370	* room for the payload but does not copy it.
	371	*
	372	* Returns NULL if the tailroom of the skb is insufficient to store
	373	* the attribute header and payload.
	374	*/
	375	struct nlattr nla_reserve(struct sk_buff skb, int attrtype, int attrlen)
	376	{
	377	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
	378	return NULL;
	379
	380	return __nla_reserve(skb, attrtype, attrlen);
	381	}
90800216	382	EXPORT_SYMBOL(nla_reserve);
bfa83a9e	383
fe4944e5	384	/**
10b595af	385	* nla_reserve_nohdr - reserve room for attribute without header
fe4944e5	386	* @skb: socket buffer to reserve room on
10b595af	387	* @attrlen: length of attribute payload
fe4944e5 TG	388	*
	389	* Reserves room for attribute payload without a header.
	390	*
	391	* Returns NULL if the tailroom of the skb is insufficient to store
	392	* the attribute payload.
	393	*/
	394	void nla_reserve_nohdr(struct sk_buff skb, int attrlen)
	395	{
	396	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
	397	return NULL;
	398
	399	return __nla_reserve_nohdr(skb, attrlen);
	400	}
90800216	401	EXPORT_SYMBOL(nla_reserve_nohdr);
fe4944e5	402
bfa83a9e TG	403	/**
	404	* __nla_put - Add a netlink attribute to a socket buffer
	405	* @skb: socket buffer to add attribute to
	406	* @attrtype: attribute type
	407	* @attrlen: length of attribute payload
	408	* @data: head of attribute payload
	409	*
	410	* The caller is responsible to ensure that the skb provides enough
	411	* tailroom for the attribute header and payload.
	412	*/
	413	void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
	414	const void *data)
	415	{
	416	struct nlattr *nla;
	417
	418	nla = __nla_reserve(skb, attrtype, attrlen);
	419	memcpy(nla_data(nla), data, attrlen);
	420	}
90800216	421	EXPORT_SYMBOL(__nla_put);
bfa83a9e	422
fe4944e5 TG	423	/**
	424	* __nla_put_nohdr - Add a netlink attribute without header
	425	* @skb: socket buffer to add attribute to
	426	* @attrlen: length of attribute payload
	427	* @data: head of attribute payload
	428	*
	429	* The caller is responsible to ensure that the skb provides enough
	430	* tailroom for the attribute payload.
	431	*/
	432	void __nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	433	{
	434	void *start;
	435
	436	start = __nla_reserve_nohdr(skb, attrlen);
	437	memcpy(start, data, attrlen);
	438	}
90800216	439	EXPORT_SYMBOL(__nla_put_nohdr);
bfa83a9e TG	440
	441	/**
	442	* nla_put - Add a netlink attribute to a socket buffer
	443	* @skb: socket buffer to add attribute to
	444	* @attrtype: attribute type
	445	* @attrlen: length of attribute payload
	446	* @data: head of attribute payload
	447	*
bc3ed28c	448	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
bfa83a9e TG	449	* the attribute header and payload.
	450	*/
	451	int nla_put(struct sk_buff skb, int attrtype, int attrlen, const void data)
	452	{
	453	if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
bc3ed28c	454	return -EMSGSIZE;
bfa83a9e TG	455
	456	__nla_put(skb, attrtype, attrlen, data);
	457	return 0;
	458	}
90800216	459	EXPORT_SYMBOL(nla_put);
bfa83a9e	460
fe4944e5 TG	461	/**
	462	* nla_put_nohdr - Add a netlink attribute without header
	463	* @skb: socket buffer to add attribute to
	464	* @attrlen: length of attribute payload
	465	* @data: head of attribute payload
	466	*
bc3ed28c	467	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
fe4944e5 TG	468	* the attribute payload.
	469	*/
	470	int nla_put_nohdr(struct sk_buff skb, int attrlen, const void data)
	471	{
	472	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	473	return -EMSGSIZE;
fe4944e5 TG	474
	475	__nla_put_nohdr(skb, attrlen, data);
	476	return 0;
	477	}
90800216	478	EXPORT_SYMBOL(nla_put_nohdr);
bfa83a9e	479
01480e1c PM	480	/**
	481	* nla_append - Add a netlink attribute without header or padding
	482	* @skb: socket buffer to add attribute to
	483	* @attrlen: length of attribute payload
	484	* @data: head of attribute payload
	485	*
bc3ed28c	486	* Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
01480e1c PM	487	* the attribute payload.
	488	*/
	489	int nla_append(struct sk_buff skb, int attrlen, const void data)
	490	{
	491	if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
bc3ed28c	492	return -EMSGSIZE;
01480e1c PM	493
	494	memcpy(skb_put(skb, attrlen), data, attrlen);
	495	return 0;
	496	}
90800216 HX	497	EXPORT_SYMBOL(nla_append);
90800216 HX	498	#endif
01480e1c	499
bfa83a9e	500	EXPORT_SYMBOL(nla_validate);
e487eb99	501	EXPORT_SYMBOL(nla_policy_len);
bfa83a9e TG	502	EXPORT_SYMBOL(nla_parse);
	503	EXPORT_SYMBOL(nla_find);
	504	EXPORT_SYMBOL(nla_strlcpy);
bfa83a9e TG	505	EXPORT_SYMBOL(nla_memcpy);
	506	EXPORT_SYMBOL(nla_memcmp);
	507	EXPORT_SYMBOL(nla_strcmp);