From a86d5ac8c9a60920f8127c197b71e295b51f510e Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Thu, 19 Apr 2018 15:52:15 -0700
Subject: [PATCH] [mle] update how timer is restarted in HandleAttachTimer

This commit updates `Mle::HandleAttachTimer()` so that the timer
`mAttachTimer` is restarted at the end of handling all state
transitions.
---
 src/core/thread/mle.cpp | 24 ++++++++++++++++--------
 src/core/thread/mle.hpp | 10 +++++-----
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/core/thread/mle.cpp b/src/core/thread/mle.cpp
index 21111f577..e12e8e3d9 100644
--- a/src/core/thread/mle.cpp
+++ b/src/core/thread/mle.cpp
@@ -1438,6 +1438,8 @@ void Mle::HandleAttachTimer(Timer &aTimer)
 
 void Mle::HandleAttachTimer(void)
 {
+    uint32_t delay = 0;
+
     switch (mAttachState)
     {
     case kAttachStateIdle:
@@ -1456,12 +1458,12 @@ void Mle::HandleAttachTimer(void)
         if (mParentRequestMode == kAttachSame1 || mParentRequestMode == kAttachSame2)
         {
             SendParentRequest(kParentRequestTypeRoutersAndReeds);
-            mAttachTimer.Start(kParentRequestReedTimeout);
+            delay = kParentRequestReedTimeout;
         }
         else
         {
             SendParentRequest(kParentRequestTypeRouters);
-            mAttachTimer.Start(kParentRequestRouterTimeout);
+            delay = kParentRequestRouterTimeout;
         }
 
         break;
@@ -1472,7 +1474,7 @@ void Mle::HandleAttachTimer(void)
         if (mParentCandidate.GetState() != Neighbor::kStateParentResponse)
         {
             SendParentRequest(kParentRequestTypeRoutersAndReeds);
-            mAttachTimer.Start(kParentRequestReedTimeout);
+            delay = kParentRequestReedTimeout;
             break;
         }
 
@@ -1484,7 +1486,7 @@ void Mle::HandleAttachTimer(void)
             SendChildIdRequest() == OT_ERROR_NONE)
         {
             mAttachState = kAttachStateChildIdRequest;
-            mAttachTimer.Start(kParentRequestReedTimeout);
+            delay        = kParentRequestReedTimeout;
             break;
         }
 
@@ -1493,14 +1495,20 @@ void Mle::HandleAttachTimer(void)
     case kAttachStateChildIdRequest:
         mAttachState = kAttachStateIdle;
         ResetParentCandidate();
-        Reattach();
+        delay = Reattach();
         break;
     }
+
+    if (delay != 0)
+    {
+        mAttachTimer.Start(delay);
+    }
 }
 
-void Mle::Reattach(void)
+uint32_t Mle::Reattach(void)
 {
     ThreadNetif &netif = GetNetif();
+    uint32_t     delay = 0;
 
     if (mReattachState == kReattachActive)
     {
@@ -1509,7 +1517,7 @@ void Mle::Reattach(void)
             netif.GetPendingDataset().ApplyConfiguration();
             mReattachState = kReattachPending;
             mAttachState   = kAttachStateStart;
-            mAttachTimer.Start(kParentRequestRouterTimeout);
+            delay          = kParentRequestRouterTimeout;
         }
         else
         {
@@ -1568,7 +1576,7 @@ void Mle::Reattach(void)
     }
 
 exit:
-    return;
+    return delay;
 }
 
 void Mle::HandleDelayedResponseTimer(Timer &aTimer)
diff --git a/src/core/thread/mle.hpp b/src/core/thread/mle.hpp
index 60b6ee45a..c77cc2118 100644
--- a/src/core/thread/mle.hpp
+++ b/src/core/thread/mle.hpp
@@ -1494,11 +1494,11 @@ private:
     otError HandleDiscoveryResponse(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     otError HandleLeaderData(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
 
-    otError SendParentRequest(ParentRequestType aType);
-    otError SendChildIdRequest(void);
-    void    SendOrphanAnnounce(void);
-    otError SendAnnounce(uint8_t aChannel, bool aOrphanAnnounce, const Ip6::Address &aDestination);
-    void    Reattach(void);
+    otError  SendParentRequest(ParentRequestType aType);
+    otError  SendChildIdRequest(void);
+    void     SendOrphanAnnounce(void);
+    otError  SendAnnounce(uint8_t aChannel, bool aOrphanAnnounce, const Ip6::Address &aDestination);
+    uint32_t Reattach(void);
 
     bool IsBetterParent(uint16_t aRloc16, uint8_t aLinkQuality, uint8_t aLinkMargin, ConnectivityTlv &aConnectivityTlv);
     void ResetParentCandidate(void);