Commit 765c9c63 authored May 18, 2015 by Erik Kline Committed by David S. Miller May 21, 2015

neigh: Better handling of transition to NUD_PROBE state



[1] When entering NUD_PROBE state via neigh_update(), perhaps received
    from userspace, correctly (re)initialize the probes count to zero.

    This is useful for forcing revalidation of a neighbor (for example
    if the host is attempting to do DNA [IPv4 4436, IPv6 6059]).

[2] Notify listeners when a neighbor goes into NUD_PROBE state.

    By sending notifications on entry to NUD_PROBE state listeners get
    more timely warnings of imminent connectivity issues.

    The current notifications on entry to NUD_STALE have somewhat
    limited usefulness: NUD_STALE is a perfectly normal state, as is
    NUD_DELAY, whereas notifications on entry to NUD_FAILURE come after
    a neighbor reachability problem has been confirmed (typically after
    three probes).

Signed-off-by: Erik Kline <ek@google.com>
Acked-By: Lorenzo Colitti <lorenzo@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 06b2c61c

net/core/neighbour.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -913,6 +913,7 @@ static void neigh_timer_handler(unsigned long arg)
		neigh->nud_state = NUD_PROBE;
		neigh->updated = jiffies;
		atomic_set(&neigh->probes, 0);
		notify = 1;
		next = now + NEIGH_VAR(neigh->parms, RETRANS_TIME);
		}
		} else {
		@@ -1144,6 +1145,8 @@ int neigh_update(struct neighbour neigh, const u8 lladdr, u8 new,

		if (new != old) {
		neigh_del_timer(neigh);
		if (new & NUD_PROBE)
		atomic_set(&neigh->probes, 0);
		if (new & NUD_IN_TIMER)
		neigh_add_timer(neigh, (jiffies +
		((new & NUD_REACHABLE) ?