From 697fb25bed94bd08c03056afee766eeb0739e828 Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Thu, 26 Mar 2026 19:40:28 -0700
Subject: [PATCH] [thread-tlvs] add missing packed macros to
 `ThreadRouterMaskTlv` (#12769)

This commit updates the `ThreadRouterMaskTlv` class definition to
include the `OT_TOOL_PACKED_BEGIN` and `OT_TOOL_PACKED_END` macros.
This class defines the structure of a TLV used in Thread messages
and directly maps to a memory buffer. Therefore, it must be properly
packed to ensure its memory footprint accurately reflects the wire
format and to prevent potential memory alignment padding.

Thankfully, this omission did not impact the format of this specific
TLV, as the alignment of its members natively matched the packed
layout.
---
 src/core/thread/thread_tlvs.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/core/thread/thread_tlvs.hpp b/src/core/thread/thread_tlvs.hpp
index ef22048e1..80380d731 100644
--- a/src/core/thread/thread_tlvs.hpp
+++ b/src/core/thread/thread_tlvs.hpp
@@ -139,6 +139,7 @@ typedef UintTlvInfo<ThreadTlv::kStatus, uint8_t> ThreadStatusTlv;
 /**
  * Implements Router Mask TLV generation and parsing.
  */
+OT_TOOL_PACKED_BEGIN
 class ThreadRouterMaskTlv : public ThreadTlv, public TlvInfo<ThreadTlv::kRouterMask>
 {
 public:
@@ -198,7 +199,7 @@ public:
 private:
     uint8_t          mIdSequence;
     Mle::RouterIdSet mAssignedRouterIdMask;
-};
+} OT_TOOL_PACKED_END;
 
 /**
  * Implements Thread Network Data TLV generation and parsing.