route: move lwtunnel state to dst_entry

Currently, the lwtunnel state resides in per-protocol data. This is
a problem if we encapsulate ipv6 traffic in an ipv4 tunnel (or vice versa).
The xmit function of the tunnel does not know whether the packet has been
routed to it by ipv4 or ipv6, yet it needs the lwtstate data. Moving the
lwtstate data to dst_entry makes such inter-protocol tunneling possible.

As a bonus, this brings a nice diffstat.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 14 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 5193618..1bf3281 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -521,7 +521,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 	__be16 df, flags;
 	int err;
 
-	tun_info = skb_tunnel_info(skb, AF_INET);
+	tun_info = skb_tunnel_info(skb);
 	if (unlikely(!tun_info || tun_info->mode != IP_TUNNEL_INFO_TX))
 		goto err_free_skb;
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 2403e85..f3087aa 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1359,7 +1359,6 @@ static void ipv4_dst_destroy(struct dst_entry *dst)
 		list_del(&rt->rt_uncached);
 		spin_unlock_bh(&ul->lock);
 	}
-	lwtstate_put(rt->rt_lwtstate);
 }
 
 void rt_flush_dev(struct net_device *dev)
@@ -1408,7 +1407,7 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 #ifdef CONFIG_IP_ROUTE_CLASSID
 		rt->dst.tclassid = nh->nh_tclassid;
 #endif
-		rt->rt_lwtstate = lwtstate_get(nh->nh_lwtstate);
+		rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);
 		if (unlikely(fnhe))
 			cached = rt_bind_exception(rt, fnhe, daddr);
 		else if (!(rt->dst.flags & DST_NOCACHE))
@@ -1494,7 +1493,6 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	rth->rt_gateway	= 0;
 	rth->rt_uses_gateway = 0;
 	INIT_LIST_HEAD(&rth->rt_uncached);
-	rth->rt_lwtstate = NULL;
 	if (our) {
 		rth->dst.input= ip_local_deliver;
 		rth->rt_flags |= RTCF_LOCAL;
@@ -1624,19 +1622,18 @@ static int __mkroute_input(struct sk_buff *skb,
 	rth->rt_gateway	= 0;
 	rth->rt_uses_gateway = 0;
 	INIT_LIST_HEAD(&rth->rt_uncached);
-	rth->rt_lwtstate = NULL;
 	RT_CACHE_STAT_INC(in_slow_tot);
 
 	rth->dst.input = ip_forward;
 	rth->dst.output = ip_output;
 
 	rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag);
-	if (lwtunnel_output_redirect(rth->rt_lwtstate)) {
-		rth->rt_lwtstate->orig_output = rth->dst.output;
+	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->rt_lwtstate)) {
-		rth->rt_lwtstate->orig_input = rth->dst.input;
+	if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
+		rth->dst.lwtstate->orig_input = rth->dst.input;
 		rth->dst.input = lwtunnel_input;
 	}
 	skb_dst_set(skb, &rth->dst);
@@ -1695,7 +1692,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	   by fib_lookup.
 	 */
 
-	tun_info = skb_tunnel_info(skb, AF_INET);
+	tun_info = skb_tunnel_info(skb);
 	if (tun_info && tun_info->mode == IP_TUNNEL_INFO_RX)
 		fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id;
 	else
@@ -1815,7 +1812,6 @@ local_input:
 	rth->rt_gateway	= 0;
 	rth->rt_uses_gateway = 0;
 	INIT_LIST_HEAD(&rth->rt_uncached);
-	rth->rt_lwtstate = NULL;
 
 	RT_CACHE_STAT_INC(in_slow_tot);
 	if (res.type == RTN_UNREACHABLE) {
@@ -2006,7 +2002,6 @@ add:
 	rth->rt_gateway = 0;
 	rth->rt_uses_gateway = 0;
 	INIT_LIST_HEAD(&rth->rt_uncached);
-	rth->rt_lwtstate = NULL;
 	RT_CACHE_STAT_INC(out_slow_tot);
 
 	if (flags & RTCF_LOCAL)
@@ -2029,7 +2024,7 @@ add:
 	}
 
 	rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0);
-	if (lwtunnel_output_redirect(rth->rt_lwtstate))
+	if (lwtunnel_output_redirect(rth->dst.lwtstate))
 		rth->dst.output = lwtunnel_output;
 
 	return rth;
@@ -2293,7 +2288,6 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
 		rt->rt_uses_gateway = ort->rt_uses_gateway;
 
 		INIT_LIST_HEAD(&rt->rt_uncached);
-		rt->rt_lwtstate = NULL;
 		dst_free(new);
 	}