From 80c68458dc8fd3e894ef6b87f84080912cc87f71 Mon Sep 17 00:00:00 2001
From: Erik Kline <ek@google.com>
Date: Mon, 18 May 2015 19:44:41 +0900
Subject: [PATCH] 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).
Change-Id: I5b27b806736bad50723d6c48262da82bef760b71
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>
---
net/core/neighbour.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 0a68045782d1..603b4036ff02 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -935,6 +935,7 @@ 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->parms->retrans_time;
}
} else {
@@ -1162,6 +1163,8 @@ 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) ?
--
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