net: add confirm_neigh method to dst_ops

Add confirm_neigh method to dst_ops and use it from IPv4 and IPv6
to lookup and confirm the neighbour. Its usage via the new helper
dst_confirm_neigh() should be restricted to MSG_PROBE users for
performance reasons.

For XFRM prefer the last tunnel address, if present. With help
from Steffen Klassert.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 42 insertions, 0 deletions

diff --git a/include/net/arp.h b/include/net/arp.h
index 5e0f891d476c..65619a2de6f4 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -35,6 +35,22 @@ static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32
 	return n;
 }
 
+static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key)
+{
+	struct neighbour *n;
+
+	rcu_read_lock_bh();
+	n = __ipv4_neigh_lookup_noref(dev, key);
+	if (n) {
+		unsigned long now = jiffies;
+
+		/* avoid dirtying neighbour */
+		if (n->confirmed != now)
+			n->confirmed = now;
+	}
+	rcu_read_unlock_bh();
+}
+
 void arp_init(void);
 int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
 void arp_send(int type, int ptype, __be32 dest_ip,
diff --git a/include/net/dst.h b/include/net/dst.h
index 6835d224d47b..3a3b34b83b00 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -477,6 +477,13 @@ static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst
 	return IS_ERR(n) ? NULL : n;
 }
 
+static inline void dst_confirm_neigh(const struct dst_entry *dst,
+				     const void *daddr)
+{
+	if (dst->ops->confirm_neigh)
+		dst->ops->confirm_neigh(dst, daddr);
+}
+
 static inline void dst_link_failure(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 8a2b66d8d78d..c84b3287e38b 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -33,6 +33,8 @@ struct dst_ops {
 	struct neighbour *	(*neigh_lookup)(const struct dst_entry *dst,
 						struct sk_buff *skb,
 						const void *daddr);
+	void			(*confirm_neigh)(const struct dst_entry *dst,
+						 const void *daddr);
 
 	struct kmem_cache	*kmem_cachep;
 
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index d562a2fe4860..8a0214654b6b 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -391,6 +391,23 @@ static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, cons
 	return n;
 }
 
+static inline void __ipv6_confirm_neigh(struct net_device *dev,
+					const void *pkey)
+{
+	struct neighbour *n;
+
+	rcu_read_lock_bh();
+	n = __ipv6_neigh_lookup_noref(dev, pkey);
+	if (n) {
+		unsigned long now = jiffies;
+
+		/* avoid dirtying neighbour */
+		if (n->confirmed != now)
+			n->confirmed = now;
+	}
+	rcu_read_unlock_bh();
+}
+
 int ndisc_init(void);
 int ndisc_late_init(void);