net/netlink/attr.c - kernel/msm-4.9 - Gitiles

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

 #include <linux/module.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 u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {
 	[NLA_U8]	= sizeof(u8),
 	[NLA_U16]	= sizeof(u16),
 	[NLA_U32]	= sizeof(u32),
 	[NLA_U64]	= sizeof(u64),
 	[NLA_STRING]	= 1,
 	[NLA_NESTED]	= NLA_HDRLEN,
 };

 static int validate_nla(struct nlattr *nla, int maxtype,
 			struct nla_policy *policy)
 {
 	struct nla_policy *pt;
 	int minlen = 0;

 	if (nla->nla_type <= 0 || nla->nla_type > maxtype)
 		return 0;

 	pt = &policy[nla->nla_type];

 	BUG_ON(pt->type > NLA_TYPE_MAX);

 	if (pt->minlen)
 		minlen = pt->minlen;
 	else if (pt->type != NLA_UNSPEC)
 		minlen = nla_attr_minlen[pt->type];

 	if (pt->type == NLA_FLAG && nla_len(nla) > 0)
 		return -ERANGE;

 	if (nla_len(nla) < 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(struct nlattr *head, int len, int maxtype,
 		 struct nla_policy *policy)
 {
 	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_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
  *
  * Parses a stream of attributes and stores a pointer to each attribute in
  * the tb array accessable 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, struct nlattr *head, int len,
 	      struct nla_policy *policy)
 {
 	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->nla_type;

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

 			tb[type] = 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(struct nlattr *head, int len, int attrtype)
 {
 	struct nlattr *nla;
 	int rem;

 	nla_for_each_attr(nla, head, len, rem)
 		if (nla->nla_type == attrtype)
 			return nla;

 	return NULL;
 }

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

 /**
  * __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;
 }

 /**
  * __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;
 }

 /**
  * 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);
 }

 /**
  * nla_reserve - reserve room for attribute without header
  * @skb: socket buffer to reserve room on
  * @len: 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);
 }

 /**
  * __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);
 }

 /**
  * __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);
 }

 /**
  * 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 -1 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 -1;

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

 /**
  * 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 -1 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 -1;

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

 EXPORT_SYMBOL(nla_validate);
 EXPORT_SYMBOL(nla_parse);
 EXPORT_SYMBOL(nla_find);
 EXPORT_SYMBOL(nla_strlcpy);
 EXPORT_SYMBOL(__nla_reserve);
 EXPORT_SYMBOL(__nla_reserve_nohdr);
 EXPORT_SYMBOL(nla_reserve);
 EXPORT_SYMBOL(nla_reserve_nohdr);
 EXPORT_SYMBOL(__nla_put);
 EXPORT_SYMBOL(__nla_put_nohdr);
 EXPORT_SYMBOL(nla_put);
 EXPORT_SYMBOL(nla_put_nohdr);
 EXPORT_SYMBOL(nla_memcpy);
 EXPORT_SYMBOL(nla_memcmp);
 EXPORT_SYMBOL(nla_strcmp);
	/*
	* NETLINK Netlink attributes
	*
	* Authors: Thomas Graf <tgraf@suug.ch>
	* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
	*/

	#include <linux/module.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 u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {
	[NLA_U8] = sizeof(u8),
	[NLA_U16] = sizeof(u16),
	[NLA_U32] = sizeof(u32),
	[NLA_U64] = sizeof(u64),
	[NLA_STRING] = 1,
	[NLA_NESTED] = NLA_HDRLEN,
	};

	static int validate_nla(struct nlattr *nla, int maxtype,
	struct nla_policy *policy)
	{
	struct nla_policy *pt;
	int minlen = 0;

	if (nla->nla_type <= 0 \|\| nla->nla_type > maxtype)
	return 0;

	pt = &policy[nla->nla_type];

	BUG_ON(pt->type > NLA_TYPE_MAX);

	if (pt->minlen)
	minlen = pt->minlen;
	else if (pt->type != NLA_UNSPEC)
	minlen = nla_attr_minlen[pt->type];

	if (pt->type == NLA_FLAG && nla_len(nla) > 0)
	return -ERANGE;

	if (nla_len(nla) < 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(struct nlattr *head, int len, int maxtype,
	struct nla_policy *policy)
	{
	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_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
	*
	* Parses a stream of attributes and stores a pointer to each attribute in
	* the tb array accessable 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, struct nlattr head, int len,
	struct nla_policy *policy)
	{
	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->nla_type;

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

	tb[type] = 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(struct nlattr head, int len, int attrtype)
	{
	struct nlattr *nla;
	int rem;

	nla_for_each_attr(nla, head, len, rem)
	if (nla->nla_type == attrtype)
	return nla;

	return NULL;
	}

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

	/**
	* __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;
	}

	/**
	* __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;
	}

	/**
	* 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);
	}

	/**
	* nla_reserve - reserve room for attribute without header
	* @skb: socket buffer to reserve room on
	* @len: 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);
	}

	/**
	* __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);
	}

	/**
	* __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);
	}

	/**
	* 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 -1 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 -1;

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

	/**
	* 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 -1 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 -1;

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

	EXPORT_SYMBOL(nla_validate);
	EXPORT_SYMBOL(nla_parse);
	EXPORT_SYMBOL(nla_find);
	EXPORT_SYMBOL(nla_strlcpy);
	EXPORT_SYMBOL(__nla_reserve);
	EXPORT_SYMBOL(__nla_reserve_nohdr);
	EXPORT_SYMBOL(nla_reserve);
	EXPORT_SYMBOL(nla_reserve_nohdr);
	EXPORT_SYMBOL(__nla_put);
	EXPORT_SYMBOL(__nla_put_nohdr);
	EXPORT_SYMBOL(nla_put);
	EXPORT_SYMBOL(nla_put_nohdr);
	EXPORT_SYMBOL(nla_memcpy);
	EXPORT_SYMBOL(nla_memcmp);
	EXPORT_SYMBOL(nla_strcmp);