From 4eace79c989ac42f01169504cc5bb420837c1a2e Mon Sep 17 00:00:00 2001
From: hemanth-silabs <50145824+hemanth-silabs@users.noreply.github.com>
Date: Wed, 5 Jul 2023 13:01:22 -0400
Subject: [PATCH] [spinel] return error from `SaveFrame` if not enough space is
 available (#9244)

---
 src/lib/spinel/multi_frame_buffer.hpp | 25 +++++++++++++++++++------
 src/lib/spinel/radio_spinel_impl.hpp  | 11 ++++++-----
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/src/lib/spinel/multi_frame_buffer.hpp b/src/lib/spinel/multi_frame_buffer.hpp
index 9a374cd6a..2c90d9069 100644
--- a/src/lib/spinel/multi_frame_buffer.hpp
+++ b/src/lib/spinel/multi_frame_buffer.hpp
@@ -309,14 +309,27 @@ public:
      *
      * Saved frame can be retrieved later using `GetNextSavedFrame()`.
      *
+     * @retval OT_ERROR_NONE     Successfully saved the buffer and prepared the write pointer for the next frame.
+     * @retval OT_ERROR_NO_BUFS  Insufficient buffer space.
      */
-    void SaveFrame(void)
+    otError SaveFrame(void)
     {
-        Encoding::LittleEndian::WriteUint16(GetSkipLength() + GetLength(), mWriteFrameStart + kHeaderTotalLengthOffset);
-        mWriteFrameStart = mWritePointer;
-        IgnoreError(SetSkipLength(0));
-        mWritePointer    = GetFrame();
-        mRemainingLength = static_cast<uint16_t>(mBuffer + kSize - mWritePointer);
+        otError error = OT_ERROR_NONE;
+
+        // If the next header will overflow the buffer, we can't save the frame.
+        if (!CanWrite(kHeaderSize))
+        {
+            error = OT_ERROR_NO_BUFS;
+        }
+        else
+        {
+            Encoding::LittleEndian::WriteUint16(GetSkipLength() + GetLength(),
+                                                mWriteFrameStart + kHeaderTotalLengthOffset);
+            mWriteFrameStart = mWritePointer;
+            IgnoreError(SetSkipLength(0));
+        }
+
+        return error;
     }
 
     /**
diff --git a/src/lib/spinel/radio_spinel_impl.hpp b/src/lib/spinel/radio_spinel_impl.hpp
index 35e7baa42..02898e5a7 100644
--- a/src/lib/spinel/radio_spinel_impl.hpp
+++ b/src/lib/spinel/radio_spinel_impl.hpp
@@ -530,13 +530,14 @@ void RadioSpinel<InterfaceType>::HandleNotification(SpinelInterface::RxFrameBuff
     }
 
 exit:
-    if (shouldSaveFrame)
-    {
-        aFrameBuffer.SaveFrame();
-    }
-    else
+    if (!shouldSaveFrame || aFrameBuffer.SaveFrame() != OT_ERROR_NONE)
     {
         aFrameBuffer.DiscardFrame();
+
+        if (shouldSaveFrame)
+        {
+            otLogCritPlat("RX Spinel buffer full, dropped incoming frame");
+        }
     }
 
     UpdateParseErrorCount(error);