ipv4: be more aggressive when probing alternative gateways

Currently, we do not notice if new alternative gateways
are added. We can do it by checking for present neigh
entry. Also, gateways that are currently probed (NUD_INCOMPLETE)
can be skipped from round-robin probing.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 6754c64b2fe0..d4c6732cfbfa 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -438,13 +438,15 @@ static int fib_detect_death(struct fib_info *fi, int order,
         if (n) {
                 state = n->nud_state;
                 neigh_release(n);
+        } else {
+                return 0;
         }
         if (state == NUD_REACHABLE)
                 return 0;
         if ((state & NUD_VALID) && order != dflt)
                 return 0;
         if ((state & NUD_VALID) ||
-            (*last_idx < 0 && order > dflt)) {
+            (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
                 *last_resort = fi;
                 *last_idx = order;
         }