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Commit 089bf1a6 authored by Nicolas Dichtel's avatar Nicolas Dichtel Committed by David S. Miller
Browse files

libnl: add more helpers to align attributes on 64-bit 



Signed-off-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 732912d7

include/net/netlink.h

+31 −8
Original line number Diff line number Diff line
@@ -244,13 +244,21 @@ int nla_memcpy(void *dest, const struct nlattr *src, int count); 
int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);

int nla_strcmp(const struct nlattr *nla, const char *str);

struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);

struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,

				   int attrlen, int padattr);

void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);

struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);

struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,

				 int attrlen, int padattr);

void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);

void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,

	       const void *data);

void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,

		     const void *data, int padattr);

void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);

int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);

int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,

		  const void *data, int padattr);

int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);

int nla_append(struct sk_buff *skb, int attrlen, const void *data);
@@ -1230,6 +1238,27 @@ static inline int nla_validate_nested(const struct nlattr *start, int maxtype, 
	return nla_validate(nla_data(start), nla_len(start), maxtype, policy);

}



/**

 * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute

 * @skb: socket buffer the message is stored in

 *

 * Return true if padding is needed to align the next attribute (nla_data()) to

 * a 64-bit aligned area.

 */

static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)

{

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS

	/* The nlattr header is 4 bytes in size, that's why we test

	 * if the skb->data _is_ aligned.  A NOP attribute, plus

	 * nlattr header for next attribute, will make nla_data()

	 * 8-byte aligned.

	 */

	if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))

		return true;

#endif

	return false;

}



/**

 * nla_align_64bit - 64-bit align the nla_data() of next attribute

 * @skb: socket buffer the message is stored in
@@ -1244,16 +1273,10 @@ static inline int nla_validate_nested(const struct nlattr *start, int maxtype, 
 */

static inline int nla_align_64bit(struct sk_buff *skb, int padattr)

{

#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS

	/* The nlattr header is 4 bytes in size, that's why we test

	 * if the skb->data _is_ aligned.  This NOP attribute, plus

	 * nlattr header for next attribute, will make nla_data()

	 * 8-byte aligned.

	 */

	if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8) &&

	if (nla_need_padding_for_64bit(skb) &&

	    !nla_reserve(skb, padattr, 0))

		return -EMSGSIZE;

#endif



	return 0;

}

lib/nlattr.c

+99 −0
Original line number Diff line number Diff line
@@ -354,6 +354,29 @@ struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 
}

EXPORT_SYMBOL(__nla_reserve);



/**

 * __nla_reserve_64bit - reserve room for attribute on the skb and align it

 * @skb: socket buffer to reserve room on

 * @attrtype: attribute type

 * @attrlen: length of attribute payload

 *

 * Adds a netlink attribute header to a socket buffer and reserves

 * room for the payload but does not copy it. It also ensure that this

 * attribute will be 64-bit aign.

 *

 * The caller is responsible to ensure that the skb provides enough

 * tailroom for the attribute header and payload.

 */

struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,

				   int attrlen, int padattr)

{

	if (nla_need_padding_for_64bit(skb))

		nla_align_64bit(skb, padattr);



	return __nla_reserve(skb, attrtype, attrlen);

}

EXPORT_SYMBOL(__nla_reserve_64bit);



/**

 * __nla_reserve_nohdr - reserve room for attribute without header

 * @skb: socket buffer to reserve room on
@@ -396,6 +419,35 @@ struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) 
}

EXPORT_SYMBOL(nla_reserve);



/**

 * nla_reserve_64bit - reserve room for attribute on the skb and align it

 * @skb: socket buffer to reserve room on

 * @attrtype: attribute type

 * @attrlen: length of attribute payload

 *

 * Adds a netlink attribute header to a socket buffer and reserves

 * room for the payload but does not copy it. It also ensure that this

 * attribute will be 64-bit aign.

 *

 * Returns NULL if the tailroom of the skb is insufficient to store

 * the attribute header and payload.

 */

struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,

				 int padattr)

{

	size_t len;



	if (nla_need_padding_for_64bit(skb))

		len = nla_total_size_64bit(attrlen);

	else

		len = nla_total_size(attrlen);

	if (unlikely(skb_tailroom(skb) < len))

		return NULL;



	return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);

}

EXPORT_SYMBOL(nla_reserve_64bit);



/**

 * nla_reserve_nohdr - reserve room for attribute without header

 * @skb: socket buffer to reserve room on
@@ -435,6 +487,26 @@ void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, 
}

EXPORT_SYMBOL(__nla_put);



/**

 * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it

 * @skb: socket buffer to add attribute to

 * @attrtype: attribute type

 * @attrlen: length of attribute payload

 * @data: head of attribute payload

 *

 * The caller is responsible to ensure that the skb provides enough

 * tailroom for the attribute header and payload.

 */

void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,

		     const void *data, int padattr)

{

	struct nlattr *nla;



	nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);

	memcpy(nla_data(nla), data, attrlen);

}

EXPORT_SYMBOL(__nla_put_64bit);



/**

 * __nla_put_nohdr - Add a netlink attribute without header

 * @skb: socket buffer to add attribute to
@@ -473,6 +545,33 @@ int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) 
}

EXPORT_SYMBOL(nla_put);



/**

 * nla_put_64bit - Add a netlink attribute to a socket buffer and align it

 * @skb: socket buffer to add attribute to

 * @attrtype: attribute type

 * @attrlen: length of attribute payload

 * @data: head of attribute payload

 *

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

 * the attribute header and payload.

 */

int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,

		  const void *data, int padattr)

{

	size_t len;



	if (nla_need_padding_for_64bit(skb))

		len = nla_total_size_64bit(attrlen);

	else

		len = nla_total_size(attrlen);

	if (unlikely(skb_tailroom(skb) < len))

		return -EMSGSIZE;



	__nla_put_64bit(skb, attrtype, attrlen, data, padattr);

	return 0;

}

EXPORT_SYMBOL(nla_put_64bit);



/**

 * nla_put_nohdr - Add a netlink attribute without header

 * @skb: socket buffer to add attribute to