netlink: add nla_policy_len()

It calculates the max. length of a Netlink policy, which is usefull
for allocating Netlink buffers roughly the size of the actual
message.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 8a6150a3f4c..eddb50289d6 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -230,6 +230,7 @@ extern int		nla_validate(struct nlattr *head, int len, int maxtype,
 extern int              nla_parse(struct nlattr *tb[], int maxtype,
                                   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 size_t           nla_strlcpy(char *dst, const struct nlattr *nla,
                                     size_t dstsize);