neigh: set nud_state to NUD_INCOMPLETE when probing router reachability

[ Upstream commit 2176d5d41891753774f648b67470398a5acab584 ]

Since commit 7e98056964("ipv6: router reachability probing"), a router falls
into NUD_FAILED will be probed.

Now if function rt6_select() selects a router which neighbour state is NUD_FAILED,
and at the same time function rt6_probe() changes the neighbour state to NUD_PROBE,
then function dst_neigh_output() can directly send packets, but actually the
neighbour still is unreachable. If we set nud_state to NUD_INCOMPLETE instead
NUD_PROBE, packets will not be sent out until the neihbour is reachable.

In addition, because the route should be probes with a single NS, so we must
set neigh->probes to neigh_max_probes(), then the neigh timer timeout and function
neigh_timer_handler() will not send other NS Messages.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index e161290..7d95f69 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1247,8 +1247,8 @@ void __neigh_set_probe_once(struct neighbour *neigh)
        neigh->updated = jiffies;
        if (!(neigh->nud_state & NUD_FAILED))
                return;
-       neigh->nud_state = NUD_PROBE;
-       atomic_set(&neigh->probes, NEIGH_VAR(neigh->parms, UCAST_PROBES));
+       neigh->nud_state = NUD_INCOMPLETE;
+       atomic_set(&neigh->probes, neigh_max_probes(neigh));
        neigh_add_timer(neigh,
                        jiffies + NEIGH_VAR(neigh->parms, RETRANS_TIME));
 }