netlink: constify nlmsghdr arguments

Consitfy nlmsghdr arguments to a couple of functions as preparation
for the next patch, which will constify the netlink message data in
all nfnetlink users.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 3c1895e54b7f..85ba560332ed 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -14,7 +14,7 @@ extern void	rtnl_register(int protocol, int msgtype,
 extern int      rtnl_unregister(int protocol, int msgtype);
 extern void     rtnl_unregister_all(int protocol);
 
-static inline int rtnl_msg_family(struct nlmsghdr *nlh)
+static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
 {
         if (nlmsg_len(nlh) >= sizeof(struct rtgenmsg))
                 return ((struct rtgenmsg *) nlmsg_data(nlh))->rtgen_family;