[NETLINK]: Introduce nested and byteorder flag to netlink attribute

This change allows the generic attribute interface to be used within
the netfilter subsystem where this flag was initially introduced.

The byte-order flag is yet unused, it's intended use is to
allow automatic byte order convertions for all atomic types.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/attr.c b/net/netlink/attr.c
index e4d7bed..ec39d12 100644
--- a/net/netlink/attr.c
+++ b/net/netlink/attr.c
@@ -27,12 +27,12 @@
 			const struct nla_policy *policy)
 {
 	const struct nla_policy *pt;
-	int minlen = 0, attrlen = nla_len(nla);
+	int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
 
-	if (nla->nla_type <= 0 || nla->nla_type > maxtype)
+	if (type <= 0 || type > maxtype)
 		return 0;
 
-	pt = &policy[nla->nla_type];
+	pt = &policy[type];
 
 	BUG_ON(pt->type > NLA_TYPE_MAX);
 
@@ -149,7 +149,7 @@
 	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
 
 	nla_for_each_attr(nla, head, len, rem) {
-		u16 type = nla->nla_type;
+		u16 type = nla_type(nla);
 
 		if (type > 0 && type <= maxtype) {
 			if (policy) {
@@ -185,7 +185,7 @@
 	int rem;
 
 	nla_for_each_attr(nla, head, len, rem)
-		if (nla->nla_type == attrtype)
+		if (nla_type(nla) == attrtype)
 			return nla;
 
 	return NULL;