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: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 9801c55..373f1a9 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -225,13 +225,15 @@
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 @@
* 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 @@
* @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 @@
*
* 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 @@
*
* 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);
diff --git a/lib/nlattr.c b/lib/nlattr.c
index c4706eb..00e8a02 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -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 @@
[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 @@
*
* 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 @@
*
* 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 @@
goto errout;
}
- tb[type] = nla;
+ tb[type] = (struct nlattr *)nla;
}
}
@@ -212,14 +212,14 @@
*
* 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;
}