net: Move ipv4 set_lwt_redirect helper to lwtunnel

IPv4 uses set_lwt_redirect to set the lwtunnel redirect functions as
needed. Move it to lwtunnel.h as lwtunnel_set_redirect and change
IPv6 to also use it.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/lwtunnel.h

@@ -127,6 +127,17 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 int lwtunnel_input(struct sk_buff *skb);
 int lwtunnel_xmit(struct sk_buff *skb);
 
+static inline void lwtunnel_set_redirect(struct dst_entry *dst)
+{
+	if (lwtunnel_output_redirect(dst->lwtstate)) {
+		dst->lwtstate->orig_output = dst->output;
+		dst->output = lwtunnel_output;
+	}
+	if (lwtunnel_input_redirect(dst->lwtstate)) {
+		dst->lwtstate->orig_input = dst->input;
+		dst->input = lwtunnel_input;
+	}
+}
 #else
 
 static inline void lwtstate_free(struct lwtunnel_state *lws)
@@ -158,6 +169,10 @@ static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
 	return false;
 }
 
+static inline void lwtunnel_set_redirect(struct dst_entry *dst)
+{
+}
+
 static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
 					     unsigned int mtu)
 {

net/ipv4/route.c

@@ -1645,19 +1645,6 @@ static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
 	spin_unlock_bh(&fnhe_lock);
 }
 
-static void set_lwt_redirect(struct rtable *rth)
-{
-	if (lwtunnel_output_redirect(rth->dst.lwtstate)) {
-		rth->dst.lwtstate->orig_output = rth->dst.output;
-		rth->dst.output = lwtunnel_output;
-	}
-
-	if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
-		rth->dst.lwtstate->orig_input = rth->dst.input;
-		rth->dst.input = lwtunnel_input;
-	}
-}
-
 /* called in rcu_read_lock() section */
 static int __mkroute_input(struct sk_buff *skb,
 			   const struct fib_result *res,
@@ -1748,7 +1735,7 @@ static int __mkroute_input(struct sk_buff *skb,
 
 	rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag,
 		       do_cache);
-	set_lwt_redirect(rth);
+	lwtunnel_set_redirect(&rth->dst);
 	skb_dst_set(skb, &rth->dst);
 out:
 	err = 0;
@@ -2267,7 +2254,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 	}
 
 	rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0, do_cache);
-	set_lwt_redirect(rth);
+	lwtunnel_set_redirect(&rth->dst);
 
 	return rth;
 }

net/ipv6/route.c

@@ -2671,14 +2671,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
 		if (err)
 			goto out;
 		rt->dst.lwtstate = lwtstate_get(lwtstate);
-		if (lwtunnel_output_redirect(rt->dst.lwtstate)) {
-			rt->dst.lwtstate->orig_output = rt->dst.output;
-			rt->dst.output = lwtunnel_output;
-		}
-		if (lwtunnel_input_redirect(rt->dst.lwtstate)) {
-			rt->dst.lwtstate->orig_input = rt->dst.input;
-			rt->dst.input = lwtunnel_input;
-		}
+		lwtunnel_set_redirect(&rt->dst);
 	}
 
 	ipv6_addr_prefix(&rt->rt6i_dst.addr, &cfg->fc_dst, cfg->fc_dst_len);