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Commit 3654654f authored by Jan Engelhardt's avatar Jan Engelhardt Committed by David S. Miller
Browse files

netlink: let nlmsg and nla functions take pointer-to-const args 



The changed functions do not modify the NL messages and/or attributes
at all. They should use const (similar to strchr), so that callers
which have a const nlmsg/nlattr around can make use of them without
casting.

While at it, constify a data array.

Signed-off-by: default avatarJan Engelhardt <jengelh@medozas.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9d82ca98

include/net/netlink.h

+13 −8
Original line number Diff line number Diff line
@@ -225,13 +225,15 @@ extern int nlmsg_notify(struct sock *sk, struct sk_buff *skb, 
				     u32 pid, unsigned int group, int report,

				     gfp_t flags);



extern int		nla_validate(struct nlattr *head, int len, int maxtype,

extern int		nla_validate(const struct nlattr *head,

				     int len, int maxtype,

				     const struct nla_policy *policy);

extern int		nla_parse(struct nlattr *tb[], int maxtype,

				  struct nlattr *head, int len,

extern int		nla_parse(struct nlattr **tb, int maxtype,

				  const struct nlattr *head, int len,

				  const struct nla_policy *policy);

extern int		nla_policy_len(const struct nla_policy *, int);

extern struct nlattr *	nla_find(struct nlattr *head, int len, int attrtype);

extern struct nlattr *	nla_find(const struct nlattr *head,

				 int len, int attrtype);

extern size_t		nla_strlcpy(char *dst, const struct nlattr *nla,

				    size_t dstsize);

extern int		nla_memcpy(void *dest, const struct nlattr *src, int count);
@@ -346,7 +348,8 @@ static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining) 
 * Returns the next netlink message in the message stream and

 * decrements remaining by the size of the current message.

 */

static inline struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)

static inline struct nlmsghdr *

nlmsg_next(const struct nlmsghdr *nlh, int *remaining)

{

	int totlen = NLMSG_ALIGN(nlh->nlmsg_len);
@@ -398,7 +401,8 @@ static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh, 
 * @maxtype: maximum attribute type to be expected

 * @policy: validation policy

 */

static inline int nlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,

static inline int nlmsg_validate(const struct nlmsghdr *nlh,

				 int hdrlen, int maxtype,

				 const struct nla_policy *policy)

{

	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
@@ -727,7 +731,8 @@ static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining) 
 *

 * Returns the first attribute which matches the specified type.

 */

static inline struct nlattr *nla_find_nested(struct nlattr *nla, int attrtype)

static inline struct nlattr *

nla_find_nested(const struct nlattr *nla, int attrtype)

{

	return nla_find(nla_data(nla), nla_len(nla), attrtype);

}
@@ -1032,7 +1037,7 @@ static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start) 
 *

 * Returns 0 on success or a negative error code.

 */

static inline int nla_validate_nested(struct nlattr *start, int maxtype,

static inline int nla_validate_nested(const struct nlattr *start, int maxtype,

				      const struct nla_policy *policy)

{

	return nla_validate(nla_data(start), nla_len(start), maxtype, policy);

lib/nlattr.c

+11 −11
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
#include <linux/types.h>

#include <net/netlink.h>



static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = {

static const u16 nla_attr_minlen[NLA_TYPE_MAX+1] = {

	[NLA_U8]	= sizeof(u8),

	[NLA_U16]	= sizeof(u16),

	[NLA_U32]	= sizeof(u32),
@@ -23,7 +23,7 @@ static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { 
	[NLA_NESTED]	= NLA_HDRLEN,

};



static int validate_nla(struct nlattr *nla, int maxtype,

static int validate_nla(const struct nlattr *nla, int maxtype,

			const struct nla_policy *policy)

{

	const struct nla_policy *pt;
@@ -115,10 +115,10 @@ static int validate_nla(struct nlattr *nla, int maxtype, 
 *

 * Returns 0 on success or a negative error code.

 */

int nla_validate(struct nlattr *head, int len, int maxtype,

int nla_validate(const struct nlattr *head, int len, int maxtype,

		 const struct nla_policy *policy)

{

	struct nlattr *nla;

	const struct nlattr *nla;

	int rem, err;



	nla_for_each_attr(nla, head, len, rem) {
@@ -173,10 +173,10 @@ nla_policy_len(const struct nla_policy *p, int n) 
 *

 * Returns 0 on success or a negative error code.

 */

int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,

	      const struct nla_policy *policy)

int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,

	      int len, const struct nla_policy *policy)

{

	struct nlattr *nla;

	const struct nlattr *nla;

	int rem, err;



	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
@@ -191,7 +191,7 @@ int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, 
					goto errout;

			}



			tb[type] = nla;

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

		}

	}
@@ -212,14 +212,14 @@ int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len, 
 *

 * 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_find(const struct nlattr *head, int len, int attrtype)

{

	struct nlattr *nla;

	const struct nlattr *nla;

	int rem;



	nla_for_each_attr(nla, head, len, rem)

		if (nla_type(nla) == attrtype)

			return nla;

			return (struct nlattr *)nla;



	return NULL;

}