neighbour: confirm neigh entries when ARP packet is received

[ Upstream commit f0e0d04413fcce9bc76388839099aee93cd0d33b ]

Update 'confirmed' timestamp when ARP packet is received. It shouldn't
affect locktime logic and anyway entry can be confirmed by any higher-layer
protocol. Thus it makes sense to confirm it when ARP packet is received.

Fixes: 77d7123342dc ("neighbour: update neigh timestamps iff update is effective")
Signed-off-by: Vasily Khoruzhick <vasilykh@arista.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 514d697..dcb89cb 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1174,6 +1174,12 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
                lladdr = neigh->ha;
        }
 
+       /* Update confirmed timestamp for neighbour entry after we
+        * received ARP packet even if it doesn't change IP to MAC binding.
+        */
+       if (new & NUD_CONNECTED)
+               neigh->confirmed = jiffies;
+
        /* If entry was valid and address is not changed,
           do not change entry state, if new one is STALE.
         */
@@ -1195,15 +1201,12 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
                }
        }
 
-       /* Update timestamps only once we know we will make a change to the
+       /* Update timestamp only once we know we will make a change to the
         * neighbour entry. Otherwise we risk to move the locktime window with
         * noop updates and ignore relevant ARP updates.
         */
-       if (new != old || lladdr != neigh->ha) {
-               if (new & NUD_CONNECTED)
-                       neigh->confirmed = jiffies;
+       if (new != old || lladdr != neigh->ha)
                neigh->updated = jiffies;
-       }
 
        if (new != old) {
                neigh_del_timer(neigh);