netfilter: nfnetlink: constify message attributes and headers

Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index b6ddd56..68afc6e 100644
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -620,7 +620,7 @@
 };
 
 static int
-nfnetlink_parse_nat(struct nlattr *nat,
+nfnetlink_parse_nat(const struct nlattr *nat,
 		    const struct nf_conn *ct, struct nf_nat_range *range)
 {
 	struct nlattr *tb[CTA_NAT_MAX+1];
@@ -656,7 +656,7 @@
 static int
 nfnetlink_parse_nat_setup(struct nf_conn *ct,
 			  enum nf_nat_manip_type manip,
-			  struct nlattr *attr)
+			  const struct nlattr *attr)
 {
 	struct nf_nat_range range;
 
@@ -671,7 +671,7 @@
 static int
 nfnetlink_parse_nat_setup(struct nf_conn *ct,
 			  enum nf_nat_manip_type manip,
-			  struct nlattr *attr)
+			  const struct nlattr *attr)
 {
 	return -EOPNOTSUPP;
 }