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 d81d026138f0..a793af9af150 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 2630900e480a..6e9a266a0535 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 6a5afc715558..2f40363e2851 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);