From 275d22d8d70da011f65ae3fdf5bf5dff9efba451 Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@nestlabs.com>
Date: Fri, 21 Oct 2016 21:55:45 -0700
Subject: [PATCH] Ncp: Fix join existing network feature (#865)

This commit changes the NcpBase and join-existing-network feature
by ensuring that the flag `mRequireJoinExistingNetwork` is not
cleared when role changes to detached or disabled. This fixes the
issue where a "join" command could seemingly succeed with device
forming its own partition (e.g, if a wrong network key is used).
---
 src/ncp/ncp_base.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index 9e1b784ea..06429b0bc 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -740,7 +740,16 @@ void NcpBase::UpdateChangedProps(void)
         {
             if (mRequireJoinExistingNetwork)
             {
-                mRequireJoinExistingNetwork = false;
+                switch (otGetDeviceRole(mInstance))
+                {
+                case kDeviceRoleDetached:
+                case kDeviceRoleDisabled:
+                    break;
+
+                default:
+                    mRequireJoinExistingNetwork = false;
+                    break;
+                }
 
                 if ( (otGetDeviceRole(mInstance) == kDeviceRoleLeader)
                   && otIsSingleton(mInstance)