1 files changed, 33 insertions, 3 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index cd76b3cb7092..278f46f5011b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1085,8 +1085,35 @@ restart:
         now = jiffies;
 
         if (!rt_caching(dev_net(rt->u.dst.dev))) {
-                rt_drop(rt);
-                return 0;
+                /*
+                 * If we're not caching, just tell the caller we
+                 * were successful and don't touch the route.  The
+                 * caller hold the sole reference to the cache entry, and
+                 * it will be released when the caller is done with it.
+                 * If we drop it here, the callers have no way to resolve routes
+                 * when we're not caching.  Instead, just point *rp at rt, so
+                 * the caller gets a single use out of the route
+                 * Note that we do rt_free on this new route entry, so that
+                 * once its refcount hits zero, we are still able to reap it
+                 * (Thanks Alexey)
+                 * Note also the rt_free uses call_rcu.  We don't actually
+                 * need rcu protection here, this is just our path to get
+                 * on the route gc list.
+                 */
+
+                if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
+                        int err = arp_bind_neighbour(&rt->u.dst);
+                        if (err) {
+                                if (net_ratelimit())
+                                        printk(KERN_WARNING
+                                            "Neighbour table failure & not caching routes.\n");
+                                rt_drop(rt);
+                                return err;
+                        }
+                }
+
+                rt_free(rt);
+                goto skip_hashing;
         }
 
         rthp = &rt_hash_table[hash].chain;
@@ -1203,7 +1230,8 @@ restart:
 #if RT_CACHE_DEBUG >= 2
         if (rt->u.dst.rt_next) {
                 struct rtable *trt;
-                printk(KERN_DEBUG "rt_cache @%02x: %pI4", hash, &rt->rt_dst);
+                printk(KERN_DEBUG "rt_cache @%02x: %pI4",
+                       hash, &rt->rt_dst);
                 for (trt = rt->u.dst.rt_next; trt; trt = trt->u.dst.rt_next)
                         printk(" . %pI4", &trt->rt_dst);
                 printk("\n");
@@ -1217,6 +1245,8 @@ restart:
         rcu_assign_pointer(rt_hash_table[hash].chain, rt);
 
         spin_unlock_bh(rt_hash_lock_addr(hash));
+
+skip_hashing:
         if (rp)
                 *rp = rt;
         else