neigh: Netlink notification for administrative NUD state change

The neighbour code sends up an RTM_NEWNEIGH netlink notification if
the NUD state of a neighbour cache entry is changed by a timer (e.g.
from REACHABLE to STALE), even if the lladdr of the entry has not
changed.

But an administrative change to the the NUD state of a neighbour cache
entry that does not change the lladdr (e.g. via "ip -4 neigh change
...  nud ...") does not trigger a netlink notification.  This means
that netlink listeners will not hear about administrative NUD state
changes such as from a resolved state to PERMANENT.

This patch changes the neighbor code to generate an RTM_NEWNEIGH
message when the NUD state of an entry is changed administratively.

Signed-off-by: Bob Gilligan <gilligan@aristanetworks.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index ca15f32821fb8d536586354108488050b7cc6a0e..36b1443f9ae4b38cdd7b15f645f08032acac06d0 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1161,6 +1161,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
                                                 neigh->parms->reachable_time :
                                                 0)));
                neigh->nud_state = new;
+               notify = 1;
        }
 
        if (lladdr != neigh->ha) {