From 691869834550a23ecb8aa030837000aaf9da8ab1 Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Tue, 24 Nov 2020 09:43:11 -0800
Subject: [PATCH] [mle] simplify parsing and appending of 'TimeRequestTlv'
 (#5849)

---
 src/core/thread/mle.cpp        |  7 ++-----
 src/core/thread/mle_router.cpp | 24 ++----------------------
 src/core/thread/mle_tlvs.hpp   | 26 ++------------------------
 3 files changed, 6 insertions(+), 51 deletions(-)

diff --git a/src/core/thread/mle.cpp b/src/core/thread/mle.cpp
index e5217ac0b..83d73775b 100644
--- a/src/core/thread/mle.cpp
+++ b/src/core/thread/mle.cpp
@@ -1354,11 +1354,8 @@ exit:
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
 otError Mle::AppendTimeRequest(Message &aMessage)
 {
-    TimeRequestTlv tlv;
-
-    tlv.Init();
-
-    return tlv.AppendTo(aMessage);
+    // `TimeRequestTlv` has no value.
+    return Tlv::Append<TimeRequestTlv>(aMessage, nullptr, 0);
 }
 
 otError Mle::AppendTimeParameter(Message &aMessage)
diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 582d197ce..60ccf3368 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -561,9 +561,6 @@ void MleRouter::HandleLinkRequest(const Message &aMessage, const Ip6::MessageInf
     LeaderData    leaderData;
     uint16_t      sourceAddress;
     RequestedTlvs requestedTlvs;
-#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
-    TimeRequestTlv timeRequest;
-#endif
 
     Log(kMessageReceive, kTypeLinkRequest, aMessageInfo.GetPeerAddr());
 
@@ -647,14 +644,7 @@ void MleRouter::HandleLinkRequest(const Message &aMessage, const Ip6::MessageInf
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
     if (neighbor != nullptr)
     {
-        if (Tlv::FindTlv(aMessage, timeRequest) == OT_ERROR_NONE)
-        {
-            neighbor->SetTimeSyncEnabled(true);
-        }
-        else
-        {
-            neighbor->SetTimeSyncEnabled(false);
-        }
+        neighbor->SetTimeSyncEnabled(Tlv::Find<TimeRequestTlv>(aMessage, nullptr, 0) == OT_ERROR_NONE);
     }
 #endif
 
@@ -1553,9 +1543,6 @@ void MleRouter::HandleParentRequest(const Message &aMessage, const Ip6::MessageI
     Challenge       challenge;
     Router *        leader;
     Child *         child;
-#if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
-    TimeRequestTlv timeRequest;
-#endif
 
     Log(kMessageReceive, kTypeParentRequest, aMessageInfo.GetPeerAddr());
 
@@ -1630,14 +1617,7 @@ void MleRouter::HandleParentRequest(const Message &aMessage, const Ip6::MessageI
         child->ResetLinkFailures();
         child->SetState(Neighbor::kStateParentRequest);
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
-        if (Tlv::FindTlv(aMessage, timeRequest) == OT_ERROR_NONE)
-        {
-            child->SetTimeSyncEnabled(true);
-        }
-        else
-        {
-            child->SetTimeSyncEnabled(false);
-        }
+        child->SetTimeSyncEnabled(Tlv::Find<TimeRequestTlv>(aMessage, nullptr, 0) == OT_ERROR_NONE);
 #endif
     }
     else if (TimerMilli::GetNow() - child->GetLastHeard() < kParentRequestRouterTimeout - kParentRequestDuplicateMargin)
diff --git a/src/core/thread/mle_tlvs.hpp b/src/core/thread/mle_tlvs.hpp
index 3000e427e..c25114b98 100644
--- a/src/core/thread/mle_tlvs.hpp
+++ b/src/core/thread/mle_tlvs.hpp
@@ -1142,32 +1142,10 @@ private:
 
 #if OPENTHREAD_CONFIG_TIME_SYNC_ENABLE
 /**
- * This class implements Time Request TLV generation and parsing.
+ * This class defines Time Request TLV constants and types.
  *
  */
-OT_TOOL_PACKED_BEGIN
-class TimeRequestTlv : public Tlv, public TlvInfo<Tlv::kTimeRequest>
-{
-public:
-    /**
-     * This method initializes the TLV.
-     *
-     */
-    void Init(void)
-    {
-        SetType(kTimeRequest);
-        SetLength(sizeof(*this) - sizeof(Tlv));
-    }
-
-    /**
-     * This method indicates whether or not the TLV appears to be well-formed.
-     *
-     * @retval TRUE   If the TLV appears to be well-formed.
-     * @retval FALSE  If the TLV does not appear to be well-formed.
-     *
-     */
-    bool IsValid(void) const { return GetLength() >= sizeof(*this) - sizeof(Tlv); }
-} OT_TOOL_PACKED_END;
+typedef TlvInfo<Tlv::kTimeRequest> TimeRequestTlv;
 
 /**
  * This class implements Time Parameter TLV generation and parsing.