Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[cascardo/linux.git] / net / ipv4 / fib_semantics.c

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 2b68418..d09173b 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1561,21 +1561,45 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
 }
 
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
+static bool fib_good_nh(const struct fib_nh *nh)
+{
+       int state = NUD_REACHABLE;
+
+       if (nh->nh_scope == RT_SCOPE_LINK) {
+               struct neighbour *n;
+
+               rcu_read_lock_bh();
+
+               n = __ipv4_neigh_lookup_noref(nh->nh_dev, nh->nh_gw);
+               if (n)
+                       state = n->nud_state;
+
+               rcu_read_unlock_bh();
+       }
+
+       return !!(state & NUD_VALID);
+}
 
 void fib_select_multipath(struct fib_result *res, int hash)
 {
        struct fib_info *fi = res->fi;
+       struct net *net = fi->fib_net;
+       bool first = false;
 
        for_nexthops(fi) {
                if (hash > atomic_read(&nh->nh_upper_bound))
                        continue;
 
-               res->nh_sel = nhsel;
-               return;
+               if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
+                   fib_good_nh(nh)) {
+                       res->nh_sel = nhsel;
+                       return;
+               }
+               if (!first) {
+                       res->nh_sel = nhsel;
+                       first = true;
+               }
        } endfor_nexthops(fi);
-
-       /* Race condition: route has just become dead. */
-       res->nh_sel = 0;
 }
 #endif