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>

diff --git a/include/net/arp.h b/include/net/arp.h
index 4a1f3fb..4617d98 100644 (file)
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -15,24 +15,34 @@ static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd
        return val * hash_rnd;
 }
 
-static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
+static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
 {
-       struct neigh_hash_table *nht;
+       struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht);
        struct neighbour *n;
        u32 hash_val;
 
-       rcu_read_lock_bh();
-       nht = rcu_dereference_bh(arp_tbl.nht);
+       if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
+               key = 0;
+
        hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift);
        for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
             n != NULL;
             n = rcu_dereference_bh(n->next)) {
-               if (n->dev == dev && *(u32 *)n->primary_key == key) {
-                       if (!atomic_inc_not_zero(&n->refcnt))
-                               n = NULL;
-                       break;
-               }
+               if (n->dev == dev && *(u32 *)n->primary_key == key)
+                       return n;
        }
+
+       return NULL;
+}
+
+static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
+{
+       struct neighbour *n;
+
+       rcu_read_lock_bh();
+       n = __ipv4_neigh_lookup_noref(dev, key);
+       if (n && !atomic_inc_not_zero(&n->refcnt))
+               n = NULL;
        rcu_read_unlock_bh();
 
        return n;

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 6cdfeed..e1d18bd 100644 (file)
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -202,9 +202,16 @@ extern struct neighbour *  neigh_lookup(struct neigh_table *tbl,
 extern struct neighbour *      neigh_lookup_nodev(struct neigh_table *tbl,
                                                   struct net *net,
                                                   const void *pkey);
-extern struct neighbour *      neigh_create(struct neigh_table *tbl,
+extern struct neighbour *      __neigh_create(struct neigh_table *tbl,
+                                              const void *pkey,
+                                              struct net_device *dev,
+                                              bool want_ref);
+static inline struct neighbour *neigh_create(struct neigh_table *tbl,
                                             const void *pkey,
-                                            struct net_device *dev);
+                                            struct net_device *dev)
+{
+       return __neigh_create(tbl, pkey, dev, true);
+}
 extern void                    neigh_destroy(struct neighbour *neigh);
 extern int                     __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb);
 extern int                     neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new, 

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index d81d026..a793af9 100644 (file)
--- 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 2630900..6e9a266 100644 (file)
--- 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 6a5afc7..2f40363 100644 (file)
--- 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);