From 12040b7275ff4fa4a7011ff1f559625480998700 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Thu, 13 Jul 2017 13:49:27 -0700
Subject: [PATCH] [mle] reset last heard on receiving MLE Parent Request
 (#1991)

When a child is not attached, set the last heard and timeout values on
receiving an MLE Parent Request message.  This ensures that the child
state is not prematurely timed out when a child is trying to attach.
---
 src/core/thread/mle_router.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 7d1efe11b..e17fd582a 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -1706,7 +1706,10 @@ otError MleRouter::HandleParentRequest(const Message &aMessage, const Ip6::Messa
         child->ResetLinkFailures();
         child->SetState(Neighbor::kStateParentRequest);
         child->SetDataRequestPending(false);
+    }
 
+    if (!child->IsStateValidOrRestoring())
+    {
         child->SetLastHeard(TimerMilli::GetNow());
         child->SetTimeout(TimerMilli::MsecToSec(kMaxChildIdRequestTimeout));
     }