[PATCH net-next] ipv4: be more aggressive when probing alternative gateways

[Julian Anastasov <ja@ssi.bg>]

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>
---
 net/ipv4/fib_semantics.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 6754c64..d4c6732 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;
 	}
-- 
1.9.3