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>

5 files changed, 7 insertions, 25 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
index 2578811..0a9a723 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -44,6 +44,7 @@ struct dst_entry {
 #else
 	void			*__pad1;
 #endif
+	struct lwtunnel_state   *lwtstate;
 	int			(*input)(struct sk_buff *);
 	int			(*output)(struct sock *sk, struct sk_buff *skb);
 
@@ -89,7 +90,7 @@ struct dst_entry {
 	 * (L1_CACHE_SIZE would be too much)
 	 */
 #ifdef CONFIG_64BIT
-	long			__pad_to_align_refcnt[2];
+	long			__pad_to_align_refcnt[1];
 #endif
 	/*
 	 * __refcnt wants to be on a different cache line from
diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index 075f523..2cb52d5 100644
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h
@@ -23,22 +23,17 @@ static inline struct metadata_dst *skb_metadata_dst(struct sk_buff *skb)
 	return NULL;
 }
 
-static inline struct ip_tunnel_info *skb_tunnel_info(struct sk_buff *skb,
-						     int family)
+static inline struct ip_tunnel_info *skb_tunnel_info(struct sk_buff *skb)
 {
 	struct metadata_dst *md_dst = skb_metadata_dst(skb);
-	struct rtable *rt;
+	struct dst_entry *dst;
 
 	if (md_dst)
 		return &md_dst->u.tun_info;
 
-	switch (family) {
-	case AF_INET:
-		rt = (struct rtable *)skb_dst(skb);
-		if (rt && rt->rt_lwtstate)
-			return lwt_tun_info(rt->rt_lwtstate);
-		break;
-	}
+	dst = skb_dst(skb);
+	if (dst && dst->lwtstate)
+		return lwt_tun_info(dst->lwtstate);
 
 	return NULL;
 }
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 276328e..063d304 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -133,7 +133,6 @@ struct rt6_info {
 	/* more non-fragment space at head required */
 	unsigned short			rt6i_nfheader_len;
 	u8				rt6i_protocol;
-	struct lwtunnel_state		*rt6i_lwtstate;
 };
 
 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
index cfee539..8434898 100644
--- a/include/net/lwtunnel.h
+++ b/include/net/lwtunnel.h
@@ -87,9 +87,7 @@ int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
 struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
 int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
 int lwtunnel_output(struct sock *sk, struct sk_buff *skb);
-int lwtunnel_output6(struct sock *sk, struct sk_buff *skb);
 int lwtunnel_input(struct sk_buff *skb);
-int lwtunnel_input6(struct sk_buff *skb);
 
 #else
 
@@ -164,21 +162,11 @@ static inline int lwtunnel_output(struct sock *sk, struct sk_buff *skb)
 	return -EOPNOTSUPP;
 }
 
-static inline int lwtunnel_output6(struct sock *sk, struct sk_buff *skb)
-{
-	return -EOPNOTSUPP;
-}
-
 static inline int lwtunnel_input(struct sk_buff *skb)
 {
 	return -EOPNOTSUPP;
 }
 
-static inline int lwtunnel_input6(struct sk_buff *skb)
-{
-	return -EOPNOTSUPP;
-}
-
 #endif
 
 #endif /* __NET_LWTUNNEL_H */
diff --git a/include/net/route.h b/include/net/route.h
index 6dda2c1..395d79b 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -66,7 +66,6 @@ struct rtable {
 
 	struct list_head	rt_uncached;
 	struct uncached_list	*rt_uncached_list;
-	struct lwtunnel_state   *rt_lwtstate;
 };
 
 static inline bool rt_is_input_route(const struct rtable *rt)