From: Erik Kline <ek@google.com>
Date: Mon, 18 May 2015 10:44:41 +0000 (+0900)
Subject: neigh: Better handling of transition to NUD_PROBE state
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=765c9c639fbb132af0cafc6e1da22fe6cea26bb8;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

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>
---

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 3de654256028..3a74df750af4 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -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) ?