ipv4: Make neigh lookups directly in output packet path.

Do not use the dst cached neigh, we'll be getting rid of that.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 16 insertions, 14 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index d81d026138f..a793af9af15 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -474,8 +474,8 @@ struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net,
 }
 EXPORT_SYMBOL(neigh_lookup_nodev);
 
-struct neighbour *neigh_create(struct neigh_table *tbl, const void *pkey,
-			       struct net_device *dev)
+struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
+				 struct net_device *dev, bool want_ref)
 {
 	u32 hash_val;
 	int key_len = tbl->key_len;
@@ -535,14 +535,16 @@ struct neighbour *neigh_create(struct neigh_table *tbl, const void *pkey,
 	     n1 = rcu_dereference_protected(n1->next,
 			lockdep_is_held(&tbl->lock))) {
 		if (dev == n1->dev && !memcmp(n1->primary_key, pkey, key_len)) {
-			neigh_hold(n1);
+			if (want_ref)
+				neigh_hold(n1);
 			rc = n1;
 			goto out_tbl_unlock;
 		}
 	}
 
 	n->dead = 0;
-	neigh_hold(n);
+	if (want_ref)
+		neigh_hold(n);
 	rcu_assign_pointer(n->next,
 			   rcu_dereference_protected(nht->hash_buckets[hash_val],
 						     lockdep_is_held(&tbl->lock)));
@@ -558,7 +560,7 @@ out_neigh_release:
 	neigh_release(n);
 	goto out;
 }
-EXPORT_SYMBOL(neigh_create);
+EXPORT_SYMBOL(__neigh_create);
 
 static u32 pneigh_hash(const void *pkey, int key_len)
 {
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 2630900e480..6e9a266a053 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -170,6 +170,7 @@ static inline int ip_finish_output2(struct sk_buff *skb)
 	struct net_device *dev = dst->dev;
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 	struct neighbour *neigh;
+	u32 nexthop;
 
 	if (rt->rt_type == RTN_MULTICAST) {
 		IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
@@ -191,15 +192,18 @@ static inline int ip_finish_output2(struct sk_buff *skb)
 		skb = skb2;
 	}
 
-	rcu_read_lock();
-	neigh = dst_get_neighbour_noref(dst);
+	rcu_read_lock_bh();
+	nexthop = rt->rt_gateway ? rt->rt_gateway : ip_hdr(skb)->daddr;
+	neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
+	if (unlikely(!neigh))
+		neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
 	if (neigh) {
 		int res = neigh_output(neigh, skb);
 
-		rcu_read_unlock();
+		rcu_read_unlock_bh();
 		return res;
 	}
-	rcu_read_unlock();
+	rcu_read_unlock_bh();
 
 	net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
 			    __func__);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6a5afc71555..2f40363e285 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1098,17 +1098,13 @@ static int slow_chain_length(const struct rtable *head)
 
 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr)
 {
-	static const __be32 inaddr_any = 0;
 	struct net_device *dev = dst->dev;
 	const __be32 *pkey = daddr;
 	const struct rtable *rt;
 	struct neighbour *n;
 
 	rt = (const struct rtable *) dst;
-
-	if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
-		pkey = &inaddr_any;
-	else if (rt->rt_gateway)
+	if (rt->rt_gateway)
 		pkey = (const __be32 *) &rt->rt_gateway;
 
 	n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);