[style] return void where code always returns OT_ERROR_NONE (#3543)

src/core/api/crypto_api.cpp

@@ -76,7 +76,7 @@ void otCryptoAesCcm(const uint8_t *aKey,
 
     assert((aKey != NULL) && (aNonce != NULL) && (aPlainText != NULL) && (aCipherText != NULL) && (aTag != NULL));
 
-    SuccessOrExit(aesCcm.SetKey(aKey, aKeyLength));
+    aesCcm.SetKey(aKey, aKeyLength);
     SuccessOrExit(aesCcm.Init(aHeaderLength, aLength, aTagLength, aNonce, aNonceLength));
 
     if (aHeaderLength != 0)

src/core/api/jam_detection_api.cpp

@@ -45,7 +45,9 @@ otError otJamDetectionSetRssiThreshold(otInstance *aInstance, int8_t aRssiThresh
 {
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    return instance.GetThreadNetif().GetJamDetector().SetRssiThreshold(aRssiThreshold);
+    instance.GetThreadNetif().GetJamDetector().SetRssiThreshold(aRssiThreshold);
+
+    return OT_ERROR_NONE;
 }
 
 int8_t otJamDetectionGetRssiThreshold(otInstance *aInstance)

src/core/api/joiner_api.cpp

@@ -72,14 +72,16 @@ otError otJoinerStart(otInstance *     aInstance,
 
 otError otJoinerStop(otInstance *aInstance)
 {
-    otError error = OT_ERROR_DISABLED_FEATURE;
+    otError error;
 
 #if OPENTHREAD_ENABLE_JOINER
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    error = instance.GetThreadNetif().GetJoiner().Stop();
+    instance.GetThreadNetif().GetJoiner().Stop();
+    error = OT_ERROR_NONE;
 #else
     OT_UNUSED_VARIABLE(aInstance);
+    error = OT_ERROR_DISABLED_FEATURE;
 #endif
 
     return error;

src/core/api/link_api.cpp

@@ -104,7 +104,7 @@ otError otLinkSetExtendedAddress(otInstance *aInstance, const otExtAddress *aExt
 
     instance.GetThreadNetif().GetMac().SetExtAddress(*static_cast<const Mac::ExtAddress *>(aExtAddress));
 
-    SuccessOrExit(error = instance.GetThreadNetif().GetMle().UpdateLinkLocalAddress());
+    instance.GetThreadNetif().GetMle().UpdateLinkLocalAddress();
 
 exit:
     return error;
@@ -130,7 +130,7 @@ otError otLinkSetPanId(otInstance *aInstance, otPanId aPanId)
     VerifyOrExit(instance.GetThreadNetif().GetMle().GetRole() == OT_DEVICE_ROLE_DISABLED,
                  error = OT_ERROR_INVALID_STATE);
 
-    error = instance.GetThreadNetif().GetMac().SetPanId(aPanId);
+    instance.GetThreadNetif().GetMac().SetPanId(aPanId);
     instance.GetThreadNetif().GetActiveDataset().Clear();
     instance.GetThreadNetif().GetPendingDataset().Clear();
 
@@ -318,7 +318,7 @@ otError otLinkSetEnabled(otInstance *aInstance, bool aEnable)
     // cannot disable the link layer if the Thread interface is enabled
     VerifyOrExit(instance.GetThreadNetif().IsUp() == false, error = OT_ERROR_INVALID_STATE);
 
-    error = instance.GetThreadNetif().GetMac().SetEnabled(aEnable);
+    instance.GetThreadNetif().GetMac().SetEnabled(aEnable);
 
 exit:
     return error;

src/core/api/thread_api.cpp

@@ -451,7 +451,7 @@ otError otThreadSetEnabled(otInstance *aInstance, bool aEnabled)
     }
     else
     {
-        error = instance.GetThreadNetif().GetMle().Stop(true);
+        instance.GetThreadNetif().GetMle().Stop(true);
     }
 
 exit:

src/core/api/thread_ftd_api.cpp

@@ -119,7 +119,9 @@ otError otThreadSetJoinerUdpPort(otInstance *aInstance, uint16_t aJoinerUdpPort)
 {
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    return instance.GetThreadNetif().GetJoinerRouter().SetJoinerUdpPort(aJoinerUdpPort);
+    instance.GetThreadNetif().GetJoinerRouter().SetJoinerUdpPort(aJoinerUdpPort);
+
+    return OT_ERROR_NONE;
 }
 
 uint32_t otThreadGetContextIdReuseDelay(otInstance *aInstance)

src/core/coap/coap_secure.cpp

@@ -151,7 +151,8 @@ otError CoapSecure::Disconnect(void)
     Ip6::SockAddr sockAddr;
     otError       error = OT_ERROR_NONE;
 
-    SuccessOrExit(error = GetNetif().GetDtls().Stop());
+    GetNetif().GetDtls().Stop();
+
     // Disconnect from previous peer by connecting to any address
     SuccessOrExit(error = mSocket.Connect(sockAddr));
 

src/core/common/message.cpp

@@ -493,7 +493,7 @@ exit:
     return error;
 }
 
-otError Message::RemoveHeader(uint16_t aLength)
+void Message::RemoveHeader(uint16_t aLength)
 {
     assert(aLength <= mBuffer.mHead.mInfo.mLength);
 
@@ -508,8 +508,6 @@ otError Message::RemoveHeader(uint16_t aLength)
     {
         mBuffer.mHead.mInfo.mOffset = 0;
     }
-
-    return OT_ERROR_NONE;
 }
 
 uint16_t Message::Read(uint16_t aOffset, uint16_t aLength, void *aBuf) const

src/core/common/message.hpp

@@ -387,10 +387,8 @@ public:
      *
      * @param[in]  aLength  Number of header bytes to remove.
      *
-     * @retval OT_ERROR_NONE  Successfully removed header bytes from the message.
-     *
      */
-    otError RemoveHeader(uint16_t aLength);
+    void RemoveHeader(uint16_t aLength);
 
     /**
      * This method appends bytes to the end of the message.

src/core/crypto/aes_ccm.cpp

@@ -39,10 +39,9 @@
 namespace ot {
 namespace Crypto {
 
-otError AesCcm::SetKey(const uint8_t *aKey, uint16_t aKeyLength)
+void AesCcm::SetKey(const uint8_t *aKey, uint16_t aKeyLength)
 {
     mEcb.SetKey(aKey, 8 * aKeyLength);
-    return OT_ERROR_NONE;
 }
 
 otError AesCcm::Init(uint32_t    aHeaderLength,

src/core/crypto/aes_ccm.hpp

@@ -66,7 +66,7 @@ public:
      * @param[in]  aKeyLength  Length of the key in bytes.
      *
      */
-    otError SetKey(const uint8_t *aKey, uint16_t aKeyLength);
+    void SetKey(const uint8_t *aKey, uint16_t aKeyLength);
 
     /**
      * This method initializes the AES CCM computation.

src/core/mac/mac.cpp

@@ -349,10 +349,9 @@ exit:
     return;
 }
 
-otError Mac::SetShortAddress(ShortAddress aShortAddress)
+void Mac::SetShortAddress(ShortAddress aShortAddress)
 {
     mSubMac.SetShortAddress(aShortAddress);
-    return OT_ERROR_NONE;
 }
 
 otError Mac::SetPanChannel(uint8_t aChannel)
@@ -461,7 +460,7 @@ exit:
     return error;
 }
 
-otError Mac::SetPanId(PanId aPanId)
+void Mac::SetPanId(PanId aPanId)
 {
     VerifyOrExit(mPanId != aPanId, GetNotifier().SignalIfFirst(OT_CHANGED_THREAD_PANID));
     mPanId = aPanId;
@@ -469,10 +468,10 @@ otError Mac::SetPanId(PanId aPanId)
     GetNotifier().Signal(OT_CHANGED_THREAD_PANID);
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
-otError Mac::SetExtendedPanId(const otExtendedPanId &aExtendedPanId)
+void Mac::SetExtendedPanId(const otExtendedPanId &aExtendedPanId)
 {
     VerifyOrExit(memcmp(mExtendedPanId.m8, aExtendedPanId.m8, sizeof(mExtendedPanId)) != 0,
                  GetNotifier().SignalIfFirst(OT_CHANGED_THREAD_EXT_PANID));
@@ -481,7 +480,7 @@ otError Mac::SetExtendedPanId(const otExtendedPanId &aExtendedPanId)
     GetNotifier().Signal(OT_CHANGED_THREAD_EXT_PANID);
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
 otError Mac::SendFrameRequest(void)
@@ -1756,11 +1755,9 @@ void Mac::SetPromiscuous(bool aPromiscuous)
     UpdateIdleMode();
 }
 
-otError Mac::SetEnabled(bool aEnable)
+void Mac::SetEnabled(bool aEnable)
 {
     mEnabled = aEnable;
-
-    return OT_ERROR_NONE;
 }
 
 void Mac::ResetCounters(void)

src/core/mac/mac.hpp

@@ -269,10 +269,8 @@ public:
      *
      * @param[in]  aShortAddress  The IEEE 802.15.4 Short Address.
      *
-     * @retval OT_ERROR_NONE  Successfully set the IEEE 802.15.4 Short Address.
-     *
      */
-    otError SetShortAddress(ShortAddress aShortAddress);
+    void SetShortAddress(ShortAddress aShortAddress);
 
     /**
      * This method returns the IEEE 802.15.4 PAN Channel.
@@ -395,10 +393,8 @@ public:
      *
      * @param[in]  aPanId  The IEEE 802.15.4 PAN ID.
      *
-     * @retval OT_ERROR_NONE  Successfully set the IEEE 802.15.4 PAN ID.
-     *
      */
-    otError SetPanId(PanId aPanId);
+    void SetPanId(PanId aPanId);
 
     /**
      * This method returns the IEEE 802.15.4 Extended PAN ID.
@@ -413,10 +409,8 @@ public:
      *
      * @param[in]  aExtendedPanId  The IEEE 802.15.4 Extended PAN ID.
      *
-     * @retval OT_ERROR_NONE  Successfully set the IEEE 802.15.4 Extended PAN ID.
-     *
      */
-    otError SetExtendedPanId(const otExtendedPanId &aExtendedPanId);
+    void SetExtendedPanId(const otExtendedPanId &aExtendedPanId);
 
 #if OPENTHREAD_ENABLE_MAC_FILTER
     /**
@@ -572,10 +566,8 @@ public:
      *
      * @param[in]  aEnable The requested State for the MAC layer. true - Start, false - Stop.
      *
-     * @retval OT_ERROR_NONE   The operation succeeded or the new State equals the current State.
-     *
      */
-    otError SetEnabled(bool aEnable);
+    void SetEnabled(bool aEnable);
 
     /**
      * This method indicates whether or not the link layer is enabled.

src/core/mac/mac_frame.cpp

@@ -89,7 +89,7 @@ Address::InfoString Address::ToString(void) const
                                     : (mType == kTypeNone ? InfoString("None") : InfoString("0x%04x", GetShort()));
 }
 
-otError Frame::InitMacHeader(uint16_t aFcf, uint8_t aSecurityControl)
+void Frame::InitMacHeader(uint16_t aFcf, uint8_t aSecurityControl)
 {
     uint8_t *bytes  = GetPsdu();
     uint8_t  length = 0;
@@ -180,8 +180,6 @@ otError Frame::InitMacHeader(uint16_t aFcf, uint8_t aSecurityControl)
     }
 
     SetPsduLength(length + GetFooterLength());
-
-    return OT_ERROR_NONE;
 }
 
 uint16_t Frame::GetFrameControlField(void) const
@@ -250,14 +248,12 @@ exit:
     return error;
 }
 
-otError Frame::SetDstPanId(PanId aPanId)
+void Frame::SetDstPanId(PanId aPanId)
 {
     uint8_t index = FindDstPanIdIndex();
 
     assert(index != kInvalidIndex);
     Encoding::LittleEndian::WriteUint16(aPanId, GetPsdu() + index);
-
-    return OT_ERROR_NONE;
 }
 
 uint8_t Frame::FindDstAddrIndex(void) const
@@ -291,15 +287,13 @@ exit:
     return error;
 }
 
-otError Frame::SetDstAddr(ShortAddress aShortAddress)
+void Frame::SetDstAddr(ShortAddress aShortAddress)
 {
     assert((GetFrameControlField() & kFcfDstAddrMask) == kFcfDstAddrShort);
     Encoding::LittleEndian::WriteUint16(aShortAddress, GetPsdu() + FindDstAddrIndex());
-
-    return OT_ERROR_NONE;
 }
 
-otError Frame::SetDstAddr(const ExtAddress &aExtAddress)
+void Frame::SetDstAddr(const ExtAddress &aExtAddress)
 {
     uint8_t  index = FindDstAddrIndex();
     uint8_t *buf   = GetPsdu() + index;
@@ -311,30 +305,24 @@ otError Frame::SetDstAddr(const ExtAddress &aExtAddress)
     {
         buf[i] = aExtAddress.m8[sizeof(ExtAddress) - 1 - i];
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Frame::SetDstAddr(const Address &aAddress)
+void Frame::SetDstAddr(const Address &aAddress)
 {
-    otError error = OT_ERROR_NONE;
-
     switch (aAddress.GetType())
     {
     case Address::kTypeShort:
-        error = SetDstAddr(aAddress.GetShort());
+        SetDstAddr(aAddress.GetShort());
         break;
 
     case Address::kTypeExtended:
-        error = SetDstAddr(aAddress.GetExtended());
+        SetDstAddr(aAddress.GetExtended());
         break;
 
     default:
         assert(false);
         break;
     }
-
-    return error;
 }
 
 uint8_t Frame::FindSrcPanIdIndex(void) const
@@ -471,7 +459,7 @@ exit:
     return error;
 }
 
-otError Frame::SetSrcAddr(ShortAddress aShortAddress)
+void Frame::SetSrcAddr(ShortAddress aShortAddress)
 {
     uint8_t index = FindSrcAddrIndex();
 
@@ -479,11 +467,9 @@ otError Frame::SetSrcAddr(ShortAddress aShortAddress)
     assert(index != kInvalidIndex);
 
     Encoding::LittleEndian::WriteUint16(aShortAddress, GetPsdu() + index);
-
-    return OT_ERROR_NONE;
 }
 
-otError Frame::SetSrcAddr(const ExtAddress &aExtAddress)
+void Frame::SetSrcAddr(const ExtAddress &aExtAddress)
 {
     uint8_t  index = FindSrcAddrIndex();
     uint8_t *buf   = GetPsdu() + index;
@@ -495,30 +481,24 @@ otError Frame::SetSrcAddr(const ExtAddress &aExtAddress)
     {
         buf[i] = aExtAddress.m8[sizeof(aExtAddress) - 1 - i];
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Frame::SetSrcAddr(const Address &aAddress)
+void Frame::SetSrcAddr(const Address &aAddress)
 {
-    otError error = OT_ERROR_NONE;
-
     switch (aAddress.GetType())
     {
     case Address::kTypeShort:
-        error = SetSrcAddr(aAddress.GetShort());
+        SetSrcAddr(aAddress.GetShort());
         break;
 
     case Address::kTypeExtended:
-        error = SetSrcAddr(aAddress.GetExtended());
+        SetSrcAddr(aAddress.GetExtended());
         break;
 
     default:
         assert(false);
         break;
     }
-
-    return error;
 }
 
 uint8_t Frame::FindSecurityHeaderIndex(void) const
@@ -607,7 +587,7 @@ exit:
     return error;
 }
 
-otError Frame::SetFrameCounter(uint32_t aFrameCounter)
+void Frame::SetFrameCounter(uint32_t aFrameCounter)
 {
     uint8_t index = FindSecurityHeaderIndex();
 
@@ -617,8 +597,6 @@ otError Frame::SetFrameCounter(uint32_t aFrameCounter)
     index += kSecurityControlSize;
 
     Encoding::LittleEndian::WriteUint32(aFrameCounter, GetPsdu() + index);
-
-    return OT_ERROR_NONE;
 }
 
 const uint8_t *Frame::GetKeySource(void) const
@@ -694,7 +672,7 @@ exit:
     return error;
 }
 
-otError Frame::SetKeyId(uint8_t aKeyId)
+void Frame::SetKeyId(uint8_t aKeyId)
 {
     uint8_t  keySourceLength;
     uint8_t  index = FindSecurityHeaderIndex();
@@ -707,8 +685,6 @@ otError Frame::SetKeyId(uint8_t aKeyId)
     buf += kSecurityControlSize + kFrameCounterSize + keySourceLength;
 
     buf[0] = aKeyId;
-
-    return OT_ERROR_NONE;
 }
 
 otError Frame::GetCommandId(uint8_t &aCommandId) const
@@ -802,10 +778,9 @@ uint8_t Frame::GetPayloadLength(void) const
     return GetPsduLength() - (GetHeaderLength() + GetFooterLength());
 }
 
-otError Frame::SetPayloadLength(uint8_t aLength)
+void Frame::SetPayloadLength(uint8_t aLength)
 {
     SetPsduLength(GetHeaderLength() + GetFooterLength() + aLength);
-    return OT_ERROR_NONE;
 }
 
 uint8_t Frame::SkipSecurityHeaderIndex(void) const

src/core/mac/mac_frame.hpp

@@ -552,11 +552,8 @@ public:
      * @param[in]  aFcf     The Frame Control field.
      * @param[in]  aSecCtl  The Security Control field.
      *
-     * @retval OT_ERROR_NONE          Successfully initialized the MAC header.
-     * @retval OT_ERROR_INVALID_ARGS  Invalid values for @p aFcf and/or @p aSecCtl.
-     *
      */
-    otError InitMacHeader(uint16_t aFcf, uint8_t aSecCtl);
+    void InitMacHeader(uint16_t aFcf, uint8_t aSecCtl);
 
     /**
      * This method validates the frame.
@@ -666,10 +663,8 @@ public:
      *
      * @param[in]  aPanId  The Destination PAN Identifier.
      *
-     * @retval OT_ERROR_NONE   Successfully set the Destination PAN Identifier.
-     *
      */
-    otError SetDstPanId(PanId aPanId);
+    void SetDstPanId(PanId aPanId);
 
     /**
      * This method gets the Destination Address.
@@ -686,30 +681,24 @@ public:
      *
      * @param[in]  aShortAddress  The Destination Address.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Destination Address.
-     *
      */
-    otError SetDstAddr(ShortAddress aShortAddress);
+    void SetDstAddr(ShortAddress aShortAddress);
 
     /**
      * This method sets the Destination Address.
      *
      * @param[in]  aExtAddress  The Destination Address.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Destination Address.
-     *
      */
-    otError SetDstAddr(const ExtAddress &aExtAddress);
+    void SetDstAddr(const ExtAddress &aExtAddress);
 
     /**
      * This method sets the Destination Address.
      *
      * @param[in]  aAddress  The Destination Address.
      *
-     * @retval OT_ERROR_NONE          Successfully set the Destination Address.
-     *
      */
-    otError SetDstAddr(const Address &aAddress);
+    void SetDstAddr(const Address &aAddress);
 
     /**
      * This method indicates whether or not the Src PanId is present.
@@ -754,30 +743,24 @@ public:
      *
      * @param[in]  aShortAddress  The Source Address.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Source Address.
-     *
      */
-    otError SetSrcAddr(ShortAddress aShortAddress);
+    void SetSrcAddr(ShortAddress aShortAddress);
 
     /**
      * This method sets the Source Address.
      *
      * @param[in]  aExtAddress  The Source Address.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Source Address.
-     *
      */
-    otError SetSrcAddr(const ExtAddress &aExtAddress);
+    void SetSrcAddr(const ExtAddress &aExtAddress);
 
     /**
      * This method sets the Source Address.
      *
      * @param[in]  aAddress  The Source Address.
      *
-     * @retval OT_ERROR_NONE          Successfully set the Source Address.
-     *
      */
-    otError SetSrcAddr(const Address &aAddress);
+    void SetSrcAddr(const Address &aAddress);
 
     /**
      * This method gets the Security Level Identifier.
@@ -814,10 +797,8 @@ public:
      *
      * @param[in]  aFrameCounter  The Frame Counter.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Frame Counter.
-     *
      */
-    otError SetFrameCounter(uint32_t aFrameCounter);
+    void SetFrameCounter(uint32_t aFrameCounter);
 
     /**
      * This method returns a pointer to the Key Source.
@@ -850,10 +831,8 @@ public:
      *
      * @param[in]  aKeyId  The Key Identifier.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Key Identifier.
-     *
      */
-    otError SetKeyId(uint8_t aKeyId);
+    void SetKeyId(uint8_t aKeyId);
 
     /**
      * This method gets the Command ID.
@@ -896,14 +875,8 @@ public:
      *
      * @param[in]  aLength  The MAC Frame Length.
      *
-     * @retval OT_ERROR_NONE          Successfully set the MAC Frame Length.
-     *
      */
-    otError SetLength(uint8_t aLength)
+    void SetLength(uint8_t aLength) { SetPsduLength(aLength); }
-    {
-        SetPsduLength(aLength);
-        return OT_ERROR_NONE;
-    }
 
     /**
      * This method returns the MAC header size.
@@ -940,11 +913,8 @@ public:
     /**
      * This method sets the MAC Payload length.
      *
-     * @retval OT_ERROR_NONE          Successfully set the MAC Payload length.
-     * @retval OT_ERROR_INVALID_ARGS  The @p aLength value was invalid.
-     *
      */
-    otError SetPayloadLength(uint8_t aLength);
+    void SetPayloadLength(uint8_t aLength);
 
     /**
      * This method returns the IEEE 802.15.4 channel used for transmission or reception.

src/core/meshcop/dataset.cpp

@@ -240,7 +240,7 @@ void Dataset::Get(otOperationalDataset &aDataset) const
     }
 }
 
-otError Dataset::Set(const Dataset &aDataset)
+void Dataset::Set(const Dataset &aDataset)
 {
     memcpy(mTlvs, aDataset.mTlvs, aDataset.mLength);
     mLength = aDataset.mLength;
@@ -252,8 +252,6 @@ otError Dataset::Set(const Dataset &aDataset)
     }
 
     mUpdateTime = aDataset.GetUpdateTime();
-
-    return OT_ERROR_NONE;
 }
 
 otError Dataset::Set(const otOperationalDataset &aDataset)
@@ -620,12 +618,11 @@ exit:
     return error;
 }
 
-otError Dataset::ConvertToActive(void)
+void Dataset::ConvertToActive(void)
 {
     Remove(Tlv::kPendingTimestamp);
     Remove(Tlv::kDelayTimer);
     mType = Tlv::kActiveTimestamp;
-    return OT_ERROR_NONE;
 }
 
 } // namespace MeshCoP

src/core/meshcop/dataset.hpp

@@ -187,17 +187,16 @@ public:
      *
      * @param[in]  aDataset  The input Dataset.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Dataset.
-     *
      */
-    otError Set(const Dataset &aDataset);
+    void Set(const Dataset &aDataset);
 
     /**
      * This method sets the Dataset.
      *
      * @param[in]  aDataset  The input Dataset.
      *
-     * @retval OT_ERROR_NONE  Successfully set the Dataset.
+     * @retval OT_ERROR_NONE          Successfully set the Dataset.
+     * @retval OT_ERROR_INVALID_ARGS  Dataset is missing Active and/or Pending Timestamp.
      *
      */
     otError Set(const otOperationalDataset &aDataset);
@@ -236,10 +235,8 @@ public:
      *
      * This method removes the Delay Timer and Pending Timestamp TLVs
      *
-     * @retval OT_ERROR_NONE  Successfully converted to Active Dataset.
-     *
      */
-    otError ConvertToActive(void);
+    void ConvertToActive(void);
 
 private:
     void Remove(uint8_t *aStart, uint8_t aLength);

src/core/meshcop/dtls.cpp

@@ -330,7 +330,7 @@ void Dtls::SetSslAuthMode(bool aVerifyPeerCertificate)
 
 #endif // OPENTHREAD_ENABLE_APPLICATION_COAP_SECURE
 
-otError Dtls::Stop(void)
+void Dtls::Stop(void)
 {
     VerifyOrExit((mState == kStateConnecting) || (mState == kStateConnected));
 
@@ -338,7 +338,7 @@ otError Dtls::Stop(void)
     Close();
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
 void Dtls::Close(void)
@@ -489,15 +489,13 @@ exit:
     return error;
 }
 
-otError Dtls::Receive(Message &aMessage, uint16_t aOffset, uint16_t aLength)
+void Dtls::Receive(Message &aMessage, uint16_t aOffset, uint16_t aLength)
 {
     mReceiveMessage = &aMessage;
     mReceiveOffset  = aOffset;
     mReceiveLength  = aLength;
 
     Process();
-
-    return OT_ERROR_NONE;
 }
 
 int Dtls::HandleMbedtlsTransmit(void *aContext, const unsigned char *aBuf, size_t aLength)

src/core/meshcop/dtls.hpp

@@ -150,10 +150,8 @@ public:
     /**
      * This method stops the DTLS service.
      *
-     * @retval OT_ERROR_NONE  Successfully stopped the DTLS service.
-     *
      */
-    otError Stop(void);
+    void Stop(void);
 
     /**
      * This method returns the DTLS connection state.
@@ -297,10 +295,8 @@ public:
      * @param[in]  aOffset   The offset within @p aMessage where the DTLS message starts.
      * @param[in]  aLength   The size of the DTLS message (bytes).
      *
-     * @retval OT_ERROR_NONE  Successfully processed the received DTLS message.
-     *
      */
-    otError Receive(Message &aMessage, uint16_t aOffset, uint16_t aLength);
+    void Receive(Message &aMessage, uint16_t aOffset, uint16_t aLength);
 
     /**
      * This method sets the default message sub-type that will be used for all messages without defined

src/core/meshcop/joiner.cpp

@@ -142,11 +142,9 @@ exit:
     return error;
 }
 
-otError Joiner::Stop(void)
+void Joiner::Stop(void)
 {
     Close();
-
-    return OT_ERROR_NONE;
 }
 
 otJoinerState Joiner::GetState(void) const

src/core/meshcop/joiner.hpp

@@ -90,10 +90,8 @@ public:
     /**
      * This method stops the Joiner service.
      *
-     * @retval OT_ERROR_NONE  Successfully stopped the Joiner service.
-     *
      */
-    otError Stop(void);
+    void Stop(void);
 
     /**
      * This function returns the Joiner State.

src/core/meshcop/joiner_router.cpp

@@ -121,13 +121,11 @@ exit:
     return rval;
 }
 
-otError JoinerRouter::SetJoinerUdpPort(uint16_t aJoinerUdpPort)
+void JoinerRouter::SetJoinerUdpPort(uint16_t aJoinerUdpPort)
 {
     mJoinerUdpPort          = aJoinerUdpPort;
     mIsJoinerPortConfigured = true;
     HandleStateChanged(OT_CHANGED_THREAD_NETDATA);
-
-    return OT_ERROR_NONE;
 }
 
 void JoinerRouter::HandleUdpReceive(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo)

src/core/meshcop/joiner_router.hpp

@@ -75,10 +75,8 @@ public:
      *
      * @param[in]  The Joiner UDP Port number.
      *
-     * @retval OT_ERROR_NONE    Successfully set the Joiner UDP Port.
-     *
      */
-    otError SetJoinerUdpPort(uint16_t aJoinerUdpPort);
+    void SetJoinerUdpPort(uint16_t aJoinerUdpPort);
 
 private:
     enum

src/core/net/dhcp6_client.cpp

@@ -170,7 +170,7 @@ void Dhcp6Client::UpdateAddresses(void)
     }
 }
 
-otError Dhcp6Client::Start(void)
+void Dhcp6Client::Start(void)
 {
     Ip6::SockAddr sockaddr;
 
@@ -179,14 +179,11 @@ otError Dhcp6Client::Start(void)
     mSocket.Bind(sockaddr);
 
     ProcessNextIdentityAssociation();
-
-    return OT_ERROR_NONE;
 }
 
-otError Dhcp6Client::Stop(void)
+void Dhcp6Client::Stop(void)
 {
     mSocket.Close();
-    return OT_ERROR_NONE;
 }
 
 bool Dhcp6Client::ProcessNextIdentityAssociation()

src/core/net/dhcp6_client.hpp

@@ -117,8 +117,8 @@ public:
     void UpdateAddresses(void);
 
 private:
-    otError Start(void);
+    void Start(void);
-    otError Stop(void);
+    void Stop(void);
 
     static bool MatchNetifAddressWithPrefix(const otNetifAddress &aNetifAddress, const otIp6Prefix &aIp6Prefix);
 

src/core/net/dhcp6_server.cpp

@@ -188,20 +188,18 @@ exit:
     return error;
 }
 
-otError Dhcp6Server::Start(void)
+void Dhcp6Server::Start(void)
 {
     Ip6::SockAddr sockaddr;
+
     sockaddr.mPort = kDhcpServerPort;
     mSocket.Open(&Dhcp6Server::HandleUdpReceive, this);
     mSocket.Bind(sockaddr);
-
-    return OT_ERROR_NONE;
 }
 
-otError Dhcp6Server::Stop(void)
+void Dhcp6Server::Stop(void)
 {
     mSocket.Close();
-    return OT_ERROR_NONE;
 }
 
 otError Dhcp6Server::AddPrefixAgent(otIp6Prefix &aIp6Prefix)

src/core/net/dhcp6_server.hpp

@@ -113,8 +113,8 @@ public:
     otError UpdateService();
 
 private:
-    otError Start(void);
+    void Start(void);
-    otError Stop(void);
+    void Stop(void);
 
     otError AddPrefixAgent(otIp6Prefix &aIp6Prefix);
     otError RemovePrefixAgent(const uint8_t *aIp6Address);

src/core/net/icmp6.cpp

@@ -250,7 +250,7 @@ exit:
     return error;
 }
 
-otError Icmp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
+void Icmp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
 {
     aChecksum = aMessage.UpdateChecksum(aChecksum, aMessage.GetOffset(), aMessage.GetLength() - aMessage.GetOffset());
 
@@ -261,7 +261,6 @@ otError Icmp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
 
     aChecksum = HostSwap16(aChecksum);
     aMessage.Write(aMessage.GetOffset() + IcmpHeader::GetChecksumOffset(), sizeof(aChecksum), &aChecksum);
-    return OT_ERROR_NONE;
 }
 
 } // namespace Ip6

src/core/net/icmp6.hpp

@@ -312,11 +312,8 @@ public:
      * @param[in]  aMessage               A reference to the ICMPv6 message.
      * @param[in]  aPseudoHeaderChecksum  The pseudo-header checksum value.
      *
-     * @retval OT_ERROR_NONE          Successfully updated the ICMPv6 checksum.
-     * @retval OT_ERROR_INVALID_ARGS  The message was invalid.
-     *
      */
-    otError UpdateChecksum(Message &aMessage, uint16_t aPseudoHeaderChecksum);
+    void UpdateChecksum(Message &aMessage, uint16_t aPseudoHeaderChecksum);
 
     /**
      * This method indicates whether or not ICMPv6 Echo processing is enabled.

src/core/net/ip6.cpp

@@ -487,11 +487,11 @@ otError Ip6::SendDatagram(Message &aMessage, MessageInfo &aMessageInfo, IpProto
     switch (aIpProto)
     {
     case kProtoUdp:
-        SuccessOrExit(error = mUdp.UpdateChecksum(aMessage, checksum));
+        mUdp.UpdateChecksum(aMessage, checksum);
         break;
 
     case kProtoIcmp6:
-        SuccessOrExit(error = mIcmp.UpdateChecksum(aMessage, checksum));
+        mIcmp.UpdateChecksum(aMessage, checksum);
         break;
 
     default:

src/core/net/ip6_routes.cpp

@@ -64,7 +64,7 @@ exit:
     return error;
 }
 
-otError Routes::Remove(Route &aRoute)
+void Routes::Remove(Route &aRoute)
 {
     if (&aRoute == mRoutes)
     {
@@ -83,8 +83,6 @@ otError Routes::Remove(Route &aRoute)
     }
 
     aRoute.mNext = NULL;
-
-    return OT_ERROR_NONE;
 }
 
 int8_t Routes::Lookup(const Address &aSource, const Address &aDestination)

src/core/net/ip6_routes.hpp

@@ -96,11 +96,8 @@ public:
      *
      * @param[in]  aRoute  A reference to the IPv6 route.
      *
-     * @retval OT_ERROR_NONE       Successfully removed the route.
-     * @retval OT_ERROR_NOT_FOUND  The route was not added.
-     *
      */
-    otError Remove(Route &aRoute);
+    void Remove(Route &aRoute);
 
     /**
      * This method performs source-destination route lookup.

src/core/net/udp6.cpp

@@ -76,7 +76,7 @@ Message *UdpSocket::NewMessage(uint16_t aReserved, const otMessageSettings *aSet
 
 otError UdpSocket::Open(otUdpReceive aHandler, void *aContext)
 {
-    otError error;
+    otError error = OT_ERROR_NONE;
 
     memset(&mSockName, 0, sizeof(mSockName));
     memset(&mPeerName, 0, sizeof(mPeerName));
@@ -86,9 +86,12 @@ otError UdpSocket::Open(otUdpReceive aHandler, void *aContext)
 #if OPENTHREAD_ENABLE_PLATFORM_UDP
     SuccessOrExit(error = otPlatUdpSocket(this));
 #endif
-    SuccessOrExit(error = GetUdp().AddSocket(*this));
 
+    GetUdp().AddSocket(*this);
+
+#if OPENTHREAD_ENABLE_PLATFORM_UDP
 exit:
+#endif
     return error;
 }
 
@@ -140,11 +143,14 @@ otError UdpSocket::Close(void)
 #if OPENTHREAD_ENABLE_PLATFORM_UDP
     SuccessOrExit(error = otPlatUdpClose(this));
 #endif
-    SuccessOrExit(error = GetUdp().RemoveSocket(*this));
+
+    GetUdp().RemoveSocket(*this);
     memset(&mSockName, 0, sizeof(mSockName));
     memset(&mPeerName, 0, sizeof(mPeerName));
 
+#if OPENTHREAD_ENABLE_PLATFORM_UDP
 exit:
+#endif
     return error;
 }
 
@@ -253,7 +259,7 @@ otError Udp::RemoveReceiver(UdpReceiver &aReceiver)
     return error;
 }
 
-otError Udp::AddSocket(UdpSocket &aSocket)
+void Udp::AddSocket(UdpSocket &aSocket)
 {
     for (UdpSocket *cur = mSockets; cur; cur = cur->GetNext())
     {
@@ -267,10 +273,10 @@ otError Udp::AddSocket(UdpSocket &aSocket)
     mSockets = &aSocket;
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
-otError Udp::RemoveSocket(UdpSocket &aSocket)
+void Udp::RemoveSocket(UdpSocket &aSocket)
 {
     if (mSockets == &aSocket)
     {
@@ -289,8 +295,6 @@ otError Udp::RemoveSocket(UdpSocket &aSocket)
     }
 
     aSocket.SetNext(NULL);
-
-    return OT_ERROR_NONE;
 }
 
 uint16_t Udp::GetEphemeralPort(void)
@@ -431,7 +435,7 @@ void Udp::HandlePayload(Message &aMessage, MessageInfo &aMessageInfo)
     }
 }
 
-otError Udp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
+void Udp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
 {
     aChecksum = aMessage.UpdateChecksum(aChecksum, aMessage.GetOffset(), aMessage.GetLength() - aMessage.GetOffset());
 
@@ -442,7 +446,6 @@ otError Udp::UpdateChecksum(Message &aMessage, uint16_t aChecksum)
 
     aChecksum = HostSwap16(aChecksum);
     aMessage.Write(aMessage.GetOffset() + UdpHeader::GetChecksumOffset(), sizeof(aChecksum), &aChecksum);
-    return OT_ERROR_NONE;
 }
 
 } // namespace Ip6

src/core/net/udp6.hpp

@@ -248,20 +248,16 @@ public:
      *
      * @param[in]  aSocket  A reference to the UDP socket.
      *
-     * @retval OT_ERROR_NONE  Successfully added the UDP socket.
-     *
      */
-    otError AddSocket(UdpSocket &aSocket);
+    void AddSocket(UdpSocket &aSocket);
 
     /**
      * This method removes a UDP socket.
      *
      * @param[in]  aSocket  A reference to the UDP socket.
      *
-     * @retval OT_ERROR_NONE  Successfully removed the UDP socket.
-     *
      */
-    otError RemoveSocket(UdpSocket &aSocket);
+    void RemoveSocket(UdpSocket &aSocket);
 
     /**
      * This method returns a new ephemeral port.
@@ -322,11 +318,8 @@ public:
      * @param[in]  aMessage               A reference to the UDP message.
      * @param[in]  aPseudoHeaderChecksum  The pseudo-header checksum value.
      *
-     * @retval OT_ERROR_NONE          Successfully updated the UDP checksum.
-     * @retval OT_ERROR_INVALID_ARGS  The message was invalid.
-     *
      */
-    otError UpdateChecksum(Message &aMessage, uint16_t aPseudoHeaderChecksum);
+    void UpdateChecksum(Message &aMessage, uint16_t aPseudoHeaderChecksum);
 
 #if OPENTHREAD_ENABLE_PLATFORM_UDP
     otUdpSocket *GetUdpSockets(void) { return mSockets; }

src/core/thread/key_manager.cpp

@@ -159,7 +159,7 @@ exit:
     return error;
 }
 
-otError KeyManager::ComputeKey(uint32_t aKeySequence, uint8_t *aKey)
+void KeyManager::ComputeKey(uint32_t aKeySequence, uint8_t *aKey)
 {
     Crypto::HmacSha256 hmac;
     uint8_t            keySequenceBytes[4];
@@ -174,8 +174,6 @@ otError KeyManager::ComputeKey(uint32_t aKeySequence, uint8_t *aKey)
     hmac.Update(kThreadString, sizeof(kThreadString));
 
     hmac.Finish(aKey);
-
-    return OT_ERROR_NONE;
 }
 
 void KeyManager::SetCurrentKeySequence(uint32_t aKeySequence)

src/core/thread/key_manager.hpp

@@ -335,7 +335,7 @@ private:
         kOneHourIntervalInMsec     = 3600u * 1000u,
     };
 
-    otError ComputeKey(uint32_t aKeySequence, uint8_t *aKey);
+    void ComputeKey(uint32_t aKeySequence, uint8_t *aKey);
 
     void        StartKeyRotationTimer(void);
     static void HandleKeyRotationTimer(Timer &aTimer);

src/core/thread/lowpan.cpp

@@ -53,7 +53,7 @@ Lowpan::Lowpan(Instance &aInstance)
 {
 }
 
-otError Lowpan::CopyContext(const Context &aContext, Ip6::Address &aAddress)
+void Lowpan::CopyContext(const Context &aContext, Ip6::Address &aAddress)
 {
     memcpy(&aAddress, aContext.mPrefix, aContext.mPrefixLength / CHAR_BIT);
 
@@ -62,8 +62,6 @@ otError Lowpan::CopyContext(const Context &aContext, Ip6::Address &aAddress)
         aAddress.mFields.m8[i / CHAR_BIT] &= ~(0x80 >> (i % CHAR_BIT));
         aAddress.mFields.m8[i / CHAR_BIT] |= aContext.mPrefix[i / CHAR_BIT] & (0x80 >> (i % CHAR_BIT));
     }
-
-    return OT_ERROR_NONE;
 }
 
 otError Lowpan::ComputeIid(const Mac::Address &aMacAddr, const Context &aContext, Ip6::Address &aIpAddress)

src/core/thread/lowpan.hpp

@@ -234,7 +234,7 @@ private:
     int     DecompressUdpHeader(Message &aMessage, const uint8_t *aBuf, uint16_t aBufLength, uint16_t aDatagramLength);
     otError DispatchToNextHeader(uint8_t aDispatch, Ip6::IpProto &aNextHeader);
 
-    static otError CopyContext(const Context &aContext, Ip6::Address &aAddress);
+    static void    CopyContext(const Context &aContext, Ip6::Address &aAddress);
     static otError ComputeIid(const Mac::Address &aMacAddr, const Context &aContext, Ip6::Address &aIpAddress);
 };
 

src/core/thread/mesh_forwarder.cpp

@@ -411,7 +411,7 @@ void MeshForwarder::SetRxOnWhenIdle(bool aRxOnWhenIdle)
     }
 }
 
-otError MeshForwarder::GetMacSourceAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr)
+void MeshForwarder::GetMacSourceAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -421,11 +421,9 @@ otError MeshForwarder::GetMacSourceAddress(const Ip6::Address &aIp6Addr, Mac::Ad
     {
         aMacAddr.SetShort(netif.GetMac().GetShortAddress());
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError MeshForwarder::GetMacDestinationAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr)
+void MeshForwarder::GetMacDestinationAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr)
 {
     if (aIp6Addr.IsMulticast())
     {
@@ -446,8 +444,6 @@ otError MeshForwarder::GetMacDestinationAddress(const Ip6::Address &aIp6Addr, Ma
     {
         aIp6Addr.ToExtAddress(aMacAddr);
     }
-
-    return OT_ERROR_NONE;
 }
 
 otError MeshForwarder::GetMeshHeader(const uint8_t *&aFrame, uint8_t &aFrameLength, Lowpan::MeshHeader &aMeshHeader)
@@ -586,17 +582,17 @@ otError MeshForwarder::HandleFrameRequest(Mac::Frame &aFrame)
         break;
 
     case Message::kTypeMacDataPoll:
-        error = SendPoll(*mSendMessage, aFrame);
+        SendPoll(*mSendMessage, aFrame);
         break;
 
 #if OPENTHREAD_FTD
 
     case Message::kType6lowpan:
-        error = SendMesh(*mSendMessage, aFrame);
+        SendMesh(*mSendMessage, aFrame);
         break;
 
     case Message::kTypeSupervision:
-        error              = SendEmptyFrame(aFrame, kSupervisionMsgAckRequest);
+        SendEmptyFrame(aFrame, kSupervisionMsgAckRequest);
         mMessageNextOffset = mSendMessage->GetLength();
         break;
 
@@ -651,7 +647,7 @@ exit:
     return error;
 }
 
-otError MeshForwarder::SendPoll(Message &aMessage, Mac::Frame &aFrame)
+void MeshForwarder::SendPoll(Message &aMessage, Mac::Frame &aFrame)
 {
     ThreadNetif &netif = GetNetif();
     uint16_t     fcf;
@@ -677,8 +673,6 @@ otError MeshForwarder::SendPoll(Message &aMessage, Mac::Frame &aFrame)
     aFrame.SetCommandId(Mac::Frame::kMacCmdDataRequest);
 
     mMessageNextOffset = aMessage.GetLength();
-
-    return OT_ERROR_NONE;
 }
 
 otError MeshForwarder::SendFragment(Message &aMessage, Mac::Frame &aFrame)
@@ -968,7 +962,7 @@ exit:
     return error;
 }
 
-otError MeshForwarder::SendEmptyFrame(Mac::Frame &aFrame, bool aAckRequest)
+void MeshForwarder::SendEmptyFrame(Mac::Frame &aFrame, bool aAckRequest)
 {
     ThreadNetif &netif = GetNetif();
     uint16_t     fcf;
@@ -1005,8 +999,6 @@ otError MeshForwarder::SendEmptyFrame(Mac::Frame &aFrame, bool aAckRequest)
     aFrame.SetSrcAddr(macSource);
     aFrame.SetPayloadLength(0);
     aFrame.SetFramePending(false);
-
-    return OT_ERROR_NONE;
 }
 
 void MeshForwarder::HandleSentFrame(Mac::Frame &aFrame, otError aError)

src/core/thread/mesh_forwarder.hpp

@@ -391,8 +391,8 @@ private:
                           const Mac::Address &aMacSource,
                           const Mac::Address &aMacDest,
                           Ip6::Header &       aIp6Header);
-    otError  GetMacDestinationAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr);
+    void     GetMacDestinationAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr);
-    otError  GetMacSourceAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr);
+    void     GetMacSourceAddress(const Ip6::Address &aIp6Addr, Mac::Address &aMacAddr);
     Message *GetDirectTransmission(void);
     otError  GetIndirectTransmission(void);
     Message *GetIndirectTransmission(Child &aChild);
@@ -419,10 +419,10 @@ private:
                                      uint8_t                 aFrameLength,
                                      Lowpan::FragmentHeader &aFragmentHeader);
 
-    otError SendPoll(Message &aMessage, Mac::Frame &aFrame);
+    void    SendPoll(Message &aMessage, Mac::Frame &aFrame);
-    otError SendMesh(Message &aMessage, Mac::Frame &aFrame);
+    void    SendMesh(Message &aMessage, Mac::Frame &aFrame);
     otError SendFragment(Message &aMessage, Mac::Frame &aFrame);
-    otError SendEmptyFrame(Mac::Frame &aFrame, bool aAckRequest);
+    void    SendEmptyFrame(Mac::Frame &aFrame, bool aAckRequest);
     otError UpdateIp6Route(Message &aMessage);
     otError UpdateIp6RouteFtd(Ip6::Header &ip6Header);
     otError UpdateMeshRoute(Message &aMessage);

src/core/thread/mesh_forwarder_ftd.cpp

@@ -529,7 +529,7 @@ void MeshForwarder::PrepareIndirectTransmission(Message &aMessage, const Child &
     }
 }
 
-otError MeshForwarder::SendMesh(Message &aMessage, Mac::Frame &aFrame)
+void MeshForwarder::SendMesh(Message &aMessage, Mac::Frame &aFrame)
 {
     ThreadNetif &netif = GetNetif();
     uint16_t     fcf;
@@ -550,8 +550,6 @@ otError MeshForwarder::SendMesh(Message &aMessage, Mac::Frame &aFrame)
     aFrame.SetPayloadLength(static_cast<uint8_t>(aMessage.GetLength()));
 
     mMessageNextOffset = aMessage.GetLength();
-
-    return OT_ERROR_NONE;
 }
 
 void MeshForwarder::HandleDataRequest(const Mac::Address &aMacSource, const otThreadLinkInfo &aLinkInfo)

src/core/thread/mle.cpp

@@ -228,7 +228,7 @@ otError Mle::Disable(void)
 {
     otError error = OT_ERROR_NONE;
 
-    SuccessOrExit(error = Stop(false));
+    Stop(false);
     SuccessOrExit(error = mSocket.Close());
     SuccessOrExit(error = GetNetif().RemoveUnicastAddress(mLinkLocal64));
 
@@ -280,7 +280,7 @@ exit:
     return error;
 }
 
-otError Mle::Stop(bool aClearNetworkDatasets)
+void Mle::Stop(bool aClearNetworkDatasets)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -302,7 +302,7 @@ otError Mle::Stop(bool aClearNetworkDatasets)
     SetRole(OT_DEVICE_ROLE_DISABLED);
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
 void Mle::SetRole(otDeviceRole aRole)
@@ -784,7 +784,7 @@ exit:
     return;
 }
 
-otError Mle::SetTimeout(uint32_t aTimeout)
+void Mle::SetTimeout(uint32_t aTimeout)
 {
     VerifyOrExit(mTimeout != aTimeout);
 
@@ -803,7 +803,7 @@ otError Mle::SetTimeout(uint32_t aTimeout)
     }
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
 otError Mle::SetDeviceMode(uint8_t aDeviceMode)
@@ -853,7 +853,7 @@ exit:
     return error;
 }
 
-otError Mle::UpdateLinkLocalAddress(void)
+void Mle::UpdateLinkLocalAddress(void)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -862,8 +862,6 @@ otError Mle::UpdateLinkLocalAddress(void)
     netif.AddUnicastAddress(mLinkLocal64);
 
     GetNotifier().Signal(OT_CHANGED_THREAD_LL_ADDR);
-
-    return OT_ERROR_NONE;
 }
 
 void Mle::SetMeshLocalPrefix(const otMeshLocalPrefix &aMeshLocalPrefix)
@@ -951,7 +949,7 @@ uint16_t Mle::GetRloc16(void) const
     return GetNetif().GetMac().GetShortAddress();
 }
 
-otError Mle::SetRloc16(uint16_t aRloc16)
+void Mle::SetRloc16(uint16_t aRloc16)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -966,8 +964,6 @@ otError Mle::SetRloc16(uint16_t aRloc16)
 
     netif.GetMac().SetShortAddress(aRloc16);
     netif.GetIp6().GetMpl().SetSeedId(aRloc16);
-
-    return OT_ERROR_NONE;
 }
 
 void Mle::SetLeaderData(uint32_t aPartitionId, uint8_t aWeighting, uint8_t aLeaderRouterId)

src/core/thread/mle.hpp

@@ -509,10 +509,8 @@ public:
      *
      * @param[in]  aClearNetworkDatasets  True to clear network datasets, False not.
      *
-     * @retval OT_ERROR_NONE  Successfully stopped the protocol operation.
-     *
      */
-    otError Stop(bool aClearNetworkDatasets);
+    void Stop(bool aClearNetworkDatasets);
 
     /**
      * This method restores network information from non-volatile memory.
@@ -730,10 +728,8 @@ public:
      *
      * Call this method when the IEEE 802.15.4 Extended Address has changed.
      *
-     * @retval OT_ERROR_NONE  Successfully updated the link local address.
-     *
      */
-    otError UpdateLinkLocalAddress(void);
+    void UpdateLinkLocalAddress(void);
 
     /**
      * This method returns a reference to the link-local all Thread nodes multicast address.
@@ -814,7 +810,7 @@ public:
      * @param[in]  aTimeout  The Timeout value in seconds.
      *
      */
-    otError SetTimeout(uint32_t aTimeout);
+    void SetTimeout(uint32_t aTimeout);
 
     /**
      * This method returns the RLOC16 assigned to the Thread interface.
@@ -1512,10 +1508,8 @@ protected:
      *
      * @param[in]  aRloc16  The RLOC16 to set.
      *
-     * @retval OT_ERROR_NONE  Successfully set the RLOC16.
-     *
      */
-    otError SetRloc16(uint16_t aRloc16);
+    void SetRloc16(uint16_t aRloc16);
 
     /**
      * This method sets the Device State to Detached.

src/core/thread/mle_router.cpp

@@ -194,7 +194,7 @@ otError MleRouter::BecomeLeader(void)
     netif.GetNetworkDataLeader().Reset();
     netif.GetLeader().SetEmptyCommissionerData();
 
-    SuccessOrExit(error = SetStateLeader(GetRloc16(leaderId)));
+    SetStateLeader(GetRloc16(leaderId));
 
 exit:
     return error;
@@ -213,13 +213,11 @@ void MleRouter::StopLeader(void)
     netif.UnsubscribeAllRoutersMulticast();
 }
 
-otError MleRouter::HandleDetachStart(void)
+void MleRouter::HandleDetachStart(void)
 {
     mRouterTable.ClearNeighbors();
     StopLeader();
     mStateUpdateTimer.Stop();
-
-    return OT_ERROR_NONE;
 }
 
 otError MleRouter::HandleChildStart(AttachMode aMode)
@@ -301,7 +299,7 @@ exit:
     return error;
 }
 
-otError MleRouter::SetStateRouter(uint16_t aRloc16)
+void MleRouter::SetStateRouter(uint16_t aRloc16)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -330,11 +328,9 @@ otError MleRouter::SetStateRouter(uint16_t aRloc16)
             RemoveNeighbor(*iter.GetChild());
         }
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError MleRouter::SetStateLeader(uint16_t aRloc16)
+void MleRouter::SetStateLeader(uint16_t aRloc16)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -373,8 +369,6 @@ otError MleRouter::SetStateLeader(uint16_t aRloc16)
     }
 
     otLogNoteMle("Leader partition id 0x%x", mLeaderData.GetPartitionId());
-
-    return OT_ERROR_NONE;
 }
 
 bool MleRouter::HandleAdvertiseTimer(TrickleTimer &aTimer)
@@ -1675,7 +1669,7 @@ otError MleRouter::HandleParentRequest(const Message &aMessage, const Ip6::Messa
         child->SetTimeout(TimerMilli::MsecToSec(kMaxChildIdRequestTimeout));
     }
 
-    SuccessOrExit(error = SendParentResponse(child, challenge, !scanMask.IsEndDeviceFlagSet()));
+    SendParentResponse(child, challenge, !scanMask.IsEndDeviceFlagSet());
 
 exit:
     return error;
@@ -1897,7 +1891,7 @@ exit:
     return;
 }
 
-otError MleRouter::SendParentResponse(Child *aChild, const ChallengeTlv &aChallenge, bool aRoutersOnlyRequest)
+void MleRouter::SendParentResponse(Child *aChild, const ChallengeTlv &aChallenge, bool aRoutersOnlyRequest)
 {
     otError      error = OT_ERROR_NONE;
     Ip6::Address destination;
@@ -1952,8 +1946,6 @@ exit:
     {
         message->Free();
     }
-
-    return OT_ERROR_NONE;
 }
 
 otError MleRouter::UpdateChildAddresses(const Message &aMessage, uint16_t aOffset, Child &aChild)
@@ -2540,7 +2532,7 @@ exit:
     return error;
 }
 
-otError MleRouter::HandleNetworkDataUpdateRouter(void)
+void MleRouter::HandleNetworkDataUpdateRouter(void)
 {
     static const uint8_t tlvs[] = {Tlv::kNetworkData};
     Ip6::Address         destination;
@@ -2558,7 +2550,7 @@ otError MleRouter::HandleNetworkDataUpdateRouter(void)
     SynchronizeChildNetworkData();
 
 exit:
-    return OT_ERROR_NONE;
+    return;
 }
 
 void MleRouter::SynchronizeChildNetworkData(void)
@@ -2979,11 +2971,11 @@ exit:
     return error;
 }
 
-otError MleRouter::SendChildUpdateResponse(Child *                 aChild,
+void MleRouter::SendChildUpdateResponse(Child *                 aChild,
-                                           const Ip6::MessageInfo &aMessageInfo,
+                                        const Ip6::MessageInfo &aMessageInfo,
-                                           const uint8_t *         aTlvs,
+                                        const uint8_t *         aTlvs,
-                                           uint8_t                 aTlvslength,
+                                        uint8_t                 aTlvslength,
-                                           const ChallengeTlv *    aChallenge)
+                                        const ChallengeTlv *    aChallenge)
 {
     otError  error = OT_ERROR_NONE;
     Message *message;
@@ -3056,8 +3048,6 @@ exit:
     {
         message->Free();
     }
-
-    return OT_ERROR_NONE;
 }
 
 otError MleRouter::SendDataResponse(const Ip6::Address &aDestination,
@@ -3154,13 +3144,13 @@ otError MleRouter::RemoveNeighbor(const Mac::Address &aAddress)
     Neighbor *neighbor;
 
     VerifyOrExit((neighbor = GetNeighbor(aAddress)) != NULL, error = OT_ERROR_NOT_FOUND);
-    SuccessOrExit(error = RemoveNeighbor(*neighbor));
+    RemoveNeighbor(*neighbor);
 
 exit:
     return error;
 }
 
-otError MleRouter::RemoveNeighbor(Neighbor &aNeighbor)
+void MleRouter::RemoveNeighbor(Neighbor &aNeighbor)
 {
     ThreadNetif &netif = GetNetif();
 
@@ -3210,8 +3200,6 @@ otError MleRouter::RemoveNeighbor(Neighbor &aNeighbor)
 
     aNeighbor.GetLinkInfo().Clear();
     aNeighbor.SetState(Neighbor::kStateInvalid);
-
-    return OT_ERROR_NONE;
 }
 
 Neighbor *MleRouter::GetNeighbor(uint16_t aAddress)
@@ -3980,7 +3968,7 @@ void MleRouter::HandleAddressSolicitResponse(Coap::Message *         aMessage,
     // assign short address
     SetRouterId(routerId);
 
-    SuccessOrExit(SetStateRouter(GetRloc16(mRouterId)));
+    SetStateRouter(GetRloc16(mRouterId));
     mRouterTable.Clear();
     mRouterTable.ProcessTlv(routerMaskTlv);
 
@@ -4706,13 +4694,11 @@ bool MleRouter::IsSleepyChildSubscribed(const Ip6::Address &aAddress, Child &aCh
 }
 
 #if OPENTHREAD_CONFIG_ENABLE_TIME_SYNC
-otError MleRouter::HandleTimeSync(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo)
+void MleRouter::HandleTimeSync(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo)
 {
     LogMleMessage("Receive Time Sync", aMessageInfo.GetPeerAddr());
 
     GetNetif().GetTimeSync().HandleTimeSyncMessage(aMessage);
-
-    return OT_ERROR_NONE;
 }
 
 otError MleRouter::SendTimeSync(void)

src/core/thread/mle_router_ftd.hpp

@@ -331,10 +331,8 @@ public:
      *
      * @param[in]  aNeighbor  A reference to the neighbor object.
      *
-     * @retval OT_ERROR_NONE      Successfully removed the neighbor.
-     *
      */
-    otError RemoveNeighbor(Neighbor &aNeighbor);
+    void RemoveNeighbor(Neighbor &aNeighbor);
 
     /**
      * This method gets the `ChildTable` object.
@@ -695,7 +693,7 @@ private:
     otError AppendPendingDataset(Message &aMessage);
     otError GetChildInfo(Child &aChild, otChildInfo &aChildInfo);
     otError RefreshStoredChildren(void);
-    otError HandleDetachStart(void);
+    void    HandleDetachStart(void);
     otError HandleChildStart(AttachMode aMode);
     otError HandleLinkRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     otError HandleLinkAccept(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo, uint32_t aKeySequence);
@@ -716,10 +714,10 @@ private:
                                       const Ip6::MessageInfo &aMessageInfo,
                                       uint32_t                aKeySequence);
     otError HandleDataRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
-    otError HandleNetworkDataUpdateRouter(void);
+    void    HandleNetworkDataUpdateRouter(void);
     otError HandleDiscoveryRequest(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
 #if OPENTHREAD_CONFIG_ENABLE_TIME_SYNC
-    otError HandleTimeSync(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
+    void HandleTimeSync(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
 #endif
 
     otError ProcessRouteTlv(const RouteTlv &aRoute);
@@ -734,10 +732,10 @@ private:
                            Neighbor *              aNeighbor,
                            const TlvRequestTlv &   aTlvRequest,
                            const ChallengeTlv &    aChallenge);
-    otError SendParentResponse(Child *aChild, const ChallengeTlv &aChallenge, bool aRoutersOnlyRequest);
+    void    SendParentResponse(Child *aChild, const ChallengeTlv &aChallenge, bool aRoutersOnlyRequest);
     otError SendChildIdResponse(Child &aChild);
     otError SendChildUpdateRequest(Child &aChild);
-    otError SendChildUpdateResponse(Child *                 aChild,
+    void    SendChildUpdateResponse(Child *                 aChild,
                                     const Ip6::MessageInfo &aMessageInfo,
                                     const uint8_t *         aTlvs,
                                     uint8_t                 aTlvsLength,
@@ -748,8 +746,8 @@ private:
                              uint16_t            aDelay);
     otError SendDiscoveryResponse(const Ip6::Address &aDestination, uint16_t aPanId);
 
-    otError SetStateRouter(uint16_t aRloc16);
+    void    SetStateRouter(uint16_t aRloc16);
-    otError SetStateLeader(uint16_t aRloc16);
+    void    SetStateLeader(uint16_t aRloc16);
     void    StopLeader(void);
     void    SynchronizeChildNetworkData(void);
     otError UpdateChildAddresses(const Message &aMessage, uint16_t aOffset, Child &aChild);

src/core/thread/mle_router_mtd.hpp

@@ -130,7 +130,7 @@ public:
     bool IsSleepyChildSubscribed(const Ip6::Address &, Child &) { return false; }
 
 private:
-    otError HandleDetachStart(void) { return OT_ERROR_NONE; }
+    void    HandleDetachStart(void) {}
     otError HandleChildStart(AttachMode) { return OT_ERROR_NONE; }
     otError HandleLinkRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
     otError HandleLinkAccept(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
@@ -142,7 +142,7 @@ private:
     otError HandleChildUpdateRequest(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
     otError HandleChildUpdateResponse(const Message &, const Ip6::MessageInfo &, uint32_t) { return OT_ERROR_DROP; }
     otError HandleDataRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
-    otError HandleNetworkDataUpdateRouter(void) { return OT_ERROR_NONE; }
+    void    HandleNetworkDataUpdateRouter(void) {}
     otError HandleDiscoveryRequest(const Message &, const Ip6::MessageInfo &) { return OT_ERROR_DROP; }
     void    HandlePartitionChange(void) {}
     void    StopAdvertiseTimer(void) {}

src/core/thread/network_data.cpp

@@ -979,20 +979,18 @@ exit:
 }
 #endif
 
-otError NetworkData::Insert(uint8_t *aStart, uint8_t aLength)
+void NetworkData::Insert(uint8_t *aStart, uint8_t aLength)
 {
     assert(aLength + mLength <= sizeof(mTlvs) && mTlvs <= aStart && aStart <= mTlvs + mLength);
     memmove(aStart + aLength, aStart, mLength - static_cast<size_t>(aStart - mTlvs));
     mLength += aLength;
-    return OT_ERROR_NONE;
 }
 
-otError NetworkData::Remove(uint8_t *aStart, uint8_t aLength)
+void NetworkData::Remove(uint8_t *aStart, uint8_t aLength)
 {
     assert(aLength <= mLength && mTlvs <= aStart && (aStart - mTlvs) + aLength <= mLength);
     memmove(aStart, aStart + aLength, mLength - (static_cast<size_t>(aStart - mTlvs) + aLength));
     mLength -= aLength;
-    return OT_ERROR_NONE;
 }
 
 otError NetworkData::SendServerDataNotification(uint16_t aRloc16)

src/core/thread/network_data.hpp

@@ -399,11 +399,8 @@ protected:
      * @param[in]  aStart   A pointer to the beginning of the insertion.
      * @param[in]  aLength  The number of bytes to insert.
      *
-     * @retval OT_ERROR_NONE          Successfully inserted bytes.
-     * @retval OT_ERROR_NO_BUFS       Insufficient buffer space to insert bytes.
-     *
      */
-    otError Insert(uint8_t *aStart, uint8_t aLength);
+    void Insert(uint8_t *aStart, uint8_t aLength);
 
     /**
      * This method removes bytes from the Network Data.
@@ -411,10 +408,8 @@ protected:
      * @param[in]  aStart   A pointer to the beginning of the removal.
      * @param[in]  aLength  The number of bytes to remove.
      *
-     * @retval OT_ERROR_NONE    Successfully removed bytes.
-     *
      */
-    otError Remove(uint8_t *aStart, uint8_t aLength);
+    void Remove(uint8_t *aStart, uint8_t aLength);
 
     /**
      * This method strips non-stable data from the Thread Network Data.

src/core/thread/network_data_leader_ftd.cpp

@@ -120,10 +120,9 @@ uint32_t Leader::GetContextIdReuseDelay(void) const
     return mContextIdReuseDelay;
 }
 
-otError Leader::SetContextIdReuseDelay(uint32_t aDelay)
+void Leader::SetContextIdReuseDelay(uint32_t aDelay)
 {
     mContextIdReuseDelay = aDelay;
-    return OT_ERROR_NONE;
 }
 
 void Leader::RemoveBorderRouter(uint16_t aRloc16, MatchMode aMatchMode)
@@ -772,7 +771,7 @@ otError Leader::RegisterNetworkData(uint16_t aRloc16, uint8_t *aTlvs, uint8_t aT
         // Store old Service IDs for given rloc16, so updates to server will reuse the same Service ID
         SuccessOrExit(error = GetNetworkData(false, oldTlvs, oldTlvsLength));
 
-        SuccessOrExit(error = RemoveRloc(aRloc16, kMatchModeRloc16));
+        RemoveRloc(aRloc16, kMatchModeRloc16);
         SuccessOrExit(error = AddNetworkData(aTlvs, aTlvsLength, oldTlvs, oldTlvsLength));
 
         mVersion++;
@@ -1197,7 +1196,7 @@ exit:
     return rval;
 }
 
-otError Leader::FreeContext(uint8_t aContextId)
+void Leader::FreeContext(uint8_t aContextId)
 {
     otLogInfoNetData("Free Context Id = %d", aContextId);
     RemoveContext(aContextId);
@@ -1205,7 +1204,6 @@ otError Leader::FreeContext(uint8_t aContextId)
     mVersion++;
     mStableVersion++;
     GetNotifier().Signal(OT_CHANGED_THREAD_NETDATA);
-    return OT_ERROR_NONE;
 }
 
 void Leader::StartContextReuseTimer(uint8_t aContextId)
@@ -1241,7 +1239,7 @@ exit:
     return error;
 }
 
-otError Leader::RemoveRloc(uint16_t aRloc16, MatchMode aMatchMode)
+void Leader::RemoveRloc(uint16_t aRloc16, MatchMode aMatchMode)
 {
     NetworkDataTlv *cur = reinterpret_cast<NetworkDataTlv *>(mTlvs);
     NetworkDataTlv *end;
@@ -1304,11 +1302,9 @@ otError Leader::RemoveRloc(uint16_t aRloc16, MatchMode aMatchMode)
     }
 
     otDumpDebgNetData("remove done", mTlvs, mLength);
-
-    return OT_ERROR_NONE;
 }
 
-otError Leader::RemoveRloc(PrefixTlv &prefix, uint16_t aRloc16, MatchMode aMatchMode)
+void Leader::RemoveRloc(PrefixTlv &prefix, uint16_t aRloc16, MatchMode aMatchMode)
 {
     NetworkDataTlv *cur = prefix.GetSubTlvs();
     NetworkDataTlv *end;
@@ -1371,12 +1367,10 @@ otError Leader::RemoveRloc(PrefixTlv &prefix, uint16_t aRloc16, MatchMode aMatch
             StopContextReuseTimer(context->GetContextId());
         }
     }
-
-    return OT_ERROR_NONE;
 }
 
 #if OPENTHREAD_ENABLE_SERVICE
-otError Leader::RemoveRloc(ServiceTlv &service, uint16_t aRloc16, MatchMode aMatchMode)
+void Leader::RemoveRloc(ServiceTlv &service, uint16_t aRloc16, MatchMode aMatchMode)
 {
     NetworkDataTlv *cur = service.GetSubTlvs();
     NetworkDataTlv *end;
@@ -1413,12 +1407,10 @@ otError Leader::RemoveRloc(ServiceTlv &service, uint16_t aRloc16, MatchMode aMat
 
         cur = cur->GetNext();
     }
-
-    return OT_ERROR_NONE;
 }
 #endif
 
-otError Leader::RemoveRloc(PrefixTlv &aPrefix, HasRouteTlv &aHasRoute, uint16_t aRloc16, MatchMode aMatchMode)
+void Leader::RemoveRloc(PrefixTlv &aPrefix, HasRouteTlv &aHasRoute, uint16_t aRloc16, MatchMode aMatchMode)
 {
     HasRouteEntry *entry = aHasRoute.GetFirstEntry();
 
@@ -1434,11 +1426,9 @@ otError Leader::RemoveRloc(PrefixTlv &aPrefix, HasRouteTlv &aHasRoute, uint16_t
 
         entry = entry->GetNext();
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Leader::RemoveRloc(PrefixTlv &aPrefix, BorderRouterTlv &aBorderRouter, uint16_t aRloc16, MatchMode aMatchMode)
+void Leader::RemoveRloc(PrefixTlv &aPrefix, BorderRouterTlv &aBorderRouter, uint16_t aRloc16, MatchMode aMatchMode)
 {
     BorderRouterEntry *entry = aBorderRouter.GetFirstEntry();
 
@@ -1454,11 +1444,9 @@ otError Leader::RemoveRloc(PrefixTlv &aPrefix, BorderRouterTlv &aBorderRouter, u
 
         entry = entry->GetNext();
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Leader::RemoveContext(uint8_t aContextId)
+void Leader::RemoveContext(uint8_t aContextId)
 {
     NetworkDataTlv *cur = reinterpret_cast<NetworkDataTlv *>(mTlvs);
     NetworkDataTlv *end;
@@ -1498,11 +1486,9 @@ otError Leader::RemoveContext(uint8_t aContextId)
     }
 
     otDumpDebgNetData("remove done", mTlvs, mLength);
-
-    return OT_ERROR_NONE;
 }
 
-otError Leader::RemoveContext(PrefixTlv &aPrefix, uint8_t aContextId)
+void Leader::RemoveContext(PrefixTlv &aPrefix, uint8_t aContextId)
 {
     NetworkDataTlv *cur = aPrefix.GetSubTlvs();
     NetworkDataTlv *end;
@@ -1542,8 +1528,6 @@ otError Leader::RemoveContext(PrefixTlv &aPrefix, uint8_t aContextId)
 
         cur = cur->GetNext();
     }
-
-    return OT_ERROR_NONE;
 }
 
 void Leader::UpdateContextsAfterReset(void)

src/core/thread/network_data_leader_ftd.hpp

@@ -129,7 +129,7 @@ public:
      * @param[in]  aDelay  The CONTEXT_ID_REUSE_DELAY value.
      *
      */
-    otError SetContextIdReuseDelay(uint32_t aDelay);
+    void SetContextIdReuseDelay(uint32_t aDelay);
 
     /**
      * This method removes Network Data entries matching with a given RLOC16.
@@ -188,23 +188,23 @@ private:
     otError AddService(ServiceTlv &aTlv, uint8_t *aOldTlvs, uint8_t aOldTlvsLength);
 #endif
 
-    int     AllocateContext(void);
+    int  AllocateContext(void);
-    otError FreeContext(uint8_t aContextId);
+    void FreeContext(uint8_t aContextId);
-    void    StartContextReuseTimer(uint8_t aContextId);
+    void StartContextReuseTimer(uint8_t aContextId);
-    void    StopContextReuseTimer(uint8_t aContextId);
+    void StopContextReuseTimer(uint8_t aContextId);
 
-    otError RemoveContext(uint8_t aContextId);
+    void RemoveContext(uint8_t aContextId);
-    otError RemoveContext(PrefixTlv &aPrefix, uint8_t aContextId);
+    void RemoveContext(PrefixTlv &aPrefix, uint8_t aContextId);
 
-    otError RemoveCommissioningData(void);
+    void RemoveCommissioningData(void);
 
-    otError RemoveRloc(uint16_t aRloc16, MatchMode aMatchMode);
+    void RemoveRloc(uint16_t aRloc16, MatchMode aMatchMode);
-    otError RemoveRloc(PrefixTlv &aPrefix, uint16_t aRloc16, MatchMode aMatchMode);
+    void RemoveRloc(PrefixTlv &aPrefix, uint16_t aRloc16, MatchMode aMatchMode);
 #if OPENTHREAD_ENABLE_SERVICE
-    otError RemoveRloc(ServiceTlv &service, uint16_t aRloc16, MatchMode aMatchMode);
+    void RemoveRloc(ServiceTlv &service, uint16_t aRloc16, MatchMode aMatchMode);
 #endif
-    otError RemoveRloc(PrefixTlv &aPrefix, HasRouteTlv &aHasRoute, uint16_t aRloc16, MatchMode aMatchMode);
+    void RemoveRloc(PrefixTlv &aPrefix, HasRouteTlv &aHasRoute, uint16_t aRloc16, MatchMode aMatchMode);
-    otError RemoveRloc(PrefixTlv &aPrefix, BorderRouterTlv &aBorderRouter, uint16_t aRloc16, MatchMode aMatchMode);
+    void RemoveRloc(PrefixTlv &aPrefix, BorderRouterTlv &aBorderRouter, uint16_t aRloc16, MatchMode aMatchMode);
 
     static bool RlocMatch(uint16_t aFirstRloc16, uint16_t aSecondRloc16, MatchMode aMatchMode);
 

src/core/thread/network_data_local.cpp

@@ -241,7 +241,7 @@ exit:
 }
 #endif
 
-otError Local::UpdateRloc(void)
+void Local::UpdateRloc(void)
 {
     for (NetworkDataTlv *cur                                            = reinterpret_cast<NetworkDataTlv *>(mTlvs);
          cur < reinterpret_cast<NetworkDataTlv *>(mTlvs + mLength); cur = cur->GetNext())
@@ -266,11 +266,9 @@ otError Local::UpdateRloc(void)
     }
 
     ClearResubmitDelayTimer();
-
-    return OT_ERROR_NONE;
 }
 
-otError Local::UpdateRloc(PrefixTlv &aPrefix)
+void Local::UpdateRloc(PrefixTlv &aPrefix)
 {
     for (NetworkDataTlv *cur = aPrefix.GetSubTlvs(); cur < aPrefix.GetNext(); cur = cur->GetNext())
     {
@@ -289,26 +287,22 @@ otError Local::UpdateRloc(PrefixTlv &aPrefix)
             break;
         }
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Local::UpdateRloc(HasRouteTlv &aHasRoute)
+void Local::UpdateRloc(HasRouteTlv &aHasRoute)
 {
     HasRouteEntry *entry = aHasRoute.GetEntry(0);
     entry->SetRloc(GetNetif().GetMle().GetRloc16());
-    return OT_ERROR_NONE;
 }
 
-otError Local::UpdateRloc(BorderRouterTlv &aBorderRouter)
+void Local::UpdateRloc(BorderRouterTlv &aBorderRouter)
 {
     BorderRouterEntry *entry = aBorderRouter.GetEntry(0);
     entry->SetRloc(GetNetif().GetMle().GetRloc16());
-    return OT_ERROR_NONE;
 }
 
 #if OPENTHREAD_ENABLE_SERVICE
-otError Local::UpdateRloc(ServiceTlv &aService)
+void Local::UpdateRloc(ServiceTlv &aService)
 {
     for (NetworkDataTlv *cur = aService.GetSubTlvs(); cur < aService.GetNext(); cur = cur->GetNext())
     {
@@ -323,14 +317,11 @@ otError Local::UpdateRloc(ServiceTlv &aService)
             break;
         }
     }
-
-    return OT_ERROR_NONE;
 }
 
-otError Local::UpdateRloc(ServerTlv &aServer)
+void Local::UpdateRloc(ServerTlv &aServer)
 {
     aServer.SetServer16(GetNetif().GetMle().GetRloc16());
-    return OT_ERROR_NONE;
 }
 #endif
 

src/core/thread/network_data_local.hpp

@@ -166,13 +166,13 @@ public:
     otError SendServerDataNotification(void);
 
 private:
-    otError UpdateRloc(void);
+    void UpdateRloc(void);
-    otError UpdateRloc(PrefixTlv &aPrefix);
+    void UpdateRloc(PrefixTlv &aPrefix);
-    otError UpdateRloc(HasRouteTlv &aHasRoute);
+    void UpdateRloc(HasRouteTlv &aHasRoute);
-    otError UpdateRloc(BorderRouterTlv &aBorderRouter);
+    void UpdateRloc(BorderRouterTlv &aBorderRouter);
 #if OPENTHREAD_ENABLE_SERVICE
-    otError UpdateRloc(ServiceTlv &aService);
+    void UpdateRloc(ServiceTlv &aService);
-    otError UpdateRloc(ServerTlv &aService);
+    void UpdateRloc(ServerTlv &aService);
 #endif
 
     bool IsOnMeshPrefixConsistent(void);

src/core/utils/jam_detector.cpp

@@ -127,12 +127,10 @@ exit:
     return;
 }
 
-otError JamDetector::SetRssiThreshold(int8_t aThreshold)
+void JamDetector::SetRssiThreshold(int8_t aThreshold)
 {
     mRssiThreshold = aThreshold;
     otLogInfoUtil("JamDetector - RSSI threshold set to %d", mRssiThreshold);
-
-    return OT_ERROR_NONE;
 }
 
 otError JamDetector::SetWindow(uint8_t aWindow)

src/core/utils/jam_detector.hpp

@@ -107,10 +107,8 @@ public:
      *
      * @param[in]  aRssiThreshold  The RSSI threshold.
      *
-     * @retval OT_ERROR_NONE       Successfully set the threshold.
-     *
      */
-    otError SetRssiThreshold(int8_t aThreshold);
+    void SetRssiThreshold(int8_t aThreshold);
 
     /**
      * Get the Jam Detection RSSI Threshold (in dBm).

src/ncp/ncp_buffer.cpp

@@ -327,7 +327,7 @@ bool NcpFrameBuffer::InFrameIsWriting(Priority aPriority) const
     return (mWriteDirection == static_cast<Direction>(aPriority));
 }
 
-otError NcpFrameBuffer::InFrameBegin(Priority aPriority)
+void NcpFrameBuffer::InFrameBegin(Priority aPriority)
 {
     // Discard any previous unfinished frame.
     InFrameDiscard();
@@ -345,8 +345,6 @@ otError NcpFrameBuffer::InFrameBegin(Priority aPriority)
 
     // Set up the segment head and tail
     mWriteSegmentHead = mWriteSegmentTail = mWriteFrameStart[mWriteDirection];
-
-    return OT_ERROR_NONE;
 }
 
 otError NcpFrameBuffer::InFrameFeedByte(uint8_t aByte)

src/ncp/ncp_buffer.hpp

@@ -161,11 +161,8 @@ public:
      *
      * @param[in] aPriority             Priority level of the new input frame.
      *
-     * @retval OT_ERROR_NONE            Successfully started a new frame.
-     * @retval OT_ERROR_NO_BUFS         Insufficient buffer space available to start a new frame.
-     *
      */
-    otError InFrameBegin(Priority aPriority);
+    void InFrameBegin(Priority aPriority);
 
     /**
      * This method adds a single byte to current input frame.

src/ncp/spinel_encoder.cpp

@@ -40,7 +40,8 @@ namespace Ncp {
 otError SpinelEncoder::BeginFrame(NcpFrameBuffer::Priority aPriority)
 {
     mNumOpenStructs = 0;
-    return mNcpBuffer.InFrameBegin(aPriority);
+    mNcpBuffer.InFrameBegin(aPriority);
+    return OT_ERROR_NONE;
 }
 
 otError SpinelEncoder::BeginFrame(uint8_t aHeader, unsigned int aCommand)

tests/unit/test_ncp_buffer.cpp

@@ -222,7 +222,7 @@ void WriteTestFrame1(NcpFrameBuffer &aNcpBuffer, NcpFrameBuffer::Priority aPrior
     message->Write(0, sizeof(sMottoText), sMottoText);
 
     oldContext = sContext;
-    SuccessOrQuit(aNcpBuffer.InFrameBegin(aPriority), "InFrameBegin() failed.");
+    aNcpBuffer.InFrameBegin(aPriority);
     SuccessOrQuit(aNcpBuffer.InFrameFeedData(sMottoText, sizeof(sMottoText)), "InFrameFeedData() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameFeedData(sMysteryText, sizeof(sMysteryText)), "InFrameFeedData() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameFeedMessage(message), "InFrameFeedMessage() failed.");
@@ -270,7 +270,7 @@ void WriteTestFrame2(NcpFrameBuffer &aNcpBuffer, NcpFrameBuffer::Priority aPrior
     SuccessOrQuit(message2->SetLength(sizeof(sHelloText)), "Could not set the length of message.");
     message2->Write(0, sizeof(sHelloText), sHelloText);
 
-    SuccessOrQuit(aNcpBuffer.InFrameBegin(aPriority), "InFrameFeedBegin() failed.");
+    aNcpBuffer.InFrameBegin(aPriority);
     SuccessOrQuit(aNcpBuffer.InFrameFeedMessage(message1), "InFrameFeedMessage() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameFeedData(sOpenThreadText, sizeof(sOpenThreadText)), "InFrameFeedData() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameFeedMessage(message2), "InFrameFeedMessage() failed.");
@@ -311,7 +311,7 @@ void WriteTestFrame3(NcpFrameBuffer &aNcpBuffer, NcpFrameBuffer::Priority aPrior
     // An empty message with no content.
     SuccessOrQuit(message1->SetLength(0), "Could not set the length of message.");
 
-    SuccessOrQuit(aNcpBuffer.InFrameBegin(aPriority), "InFrameFeedBegin() failed.");
+    aNcpBuffer.InFrameBegin(aPriority);
     SuccessOrQuit(aNcpBuffer.InFrameFeedMessage(message1), "InFrameFeedMessage() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameFeedData(sMysteryText, sizeof(sMysteryText)), "InFrameFeedData() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameEnd(), "InFrameEnd() failed.");
@@ -342,7 +342,7 @@ void WriteTestFrame4(NcpFrameBuffer &aNcpBuffer, NcpFrameBuffer::Priority aPrior
 {
     CallbackContext oldContext = sContext;
 
-    SuccessOrQuit(aNcpBuffer.InFrameBegin(aPriority), "InFrameFeedBegin() failed.");
+    aNcpBuffer.InFrameBegin(aPriority);
     SuccessOrQuit(aNcpBuffer.InFrameFeedData(sOpenThreadText, sizeof(sOpenThreadText)), "InFrameFeedData() failed.");
     SuccessOrQuit(aNcpBuffer.InFrameEnd(), "InFrameEnd() failed.");
 
@@ -732,7 +732,7 @@ void TestNcpFrameBuffer(void)
     printf("\n- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -");
     printf("\n Test 11: Read and remove in middle of an active input frame write");
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityLow);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh), "InFrameFeedBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh);
     SuccessOrQuit(ncpBuffer.InFrameFeedData(sOpenThreadText, sizeof(sOpenThreadText)), "InFrameFeedData() failed.");
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyOrQuit(ncpBuffer.IsEmpty() == true, "IsEmpty() failed.");
@@ -740,7 +740,7 @@ void TestNcpFrameBuffer(void)
     VerifyAndRemoveFrame4(ncpBuffer);
     // Repeat the test reversing priorities
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityHigh);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityLow), "InFrameFeedBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityLow);
     SuccessOrQuit(ncpBuffer.InFrameFeedData(sOpenThreadText, sizeof(sOpenThreadText)), "InFrameFeedData() failed.");
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyOrQuit(ncpBuffer.IsEmpty() == true, "IsEmpty() failed.");
@@ -748,7 +748,7 @@ void TestNcpFrameBuffer(void)
     VerifyAndRemoveFrame4(ncpBuffer);
     // Repeat the test with same priorities
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityHigh);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh), "InFrameFeedBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh);
     SuccessOrQuit(ncpBuffer.InFrameFeedData(sOpenThreadText, sizeof(sOpenThreadText)), "InFrameFeedData() failed.");
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyOrQuit(ncpBuffer.IsEmpty() == true, "IsEmpty() failed.");
@@ -759,7 +759,7 @@ void TestNcpFrameBuffer(void)
     printf("\n- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -");
     printf("\n Test 12: Check returned error status");
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityLow);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh), "InFrameFeedBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh);
     VerifyOrQuit(ncpBuffer.InFrameFeedData(buffer, sizeof(buffer)) == OT_ERROR_NO_BUFS, "Incorrect error status");
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyOrQuit(ncpBuffer.IsEmpty() == true, "IsEmpty() failed.");
@@ -791,7 +791,7 @@ void TestNcpFrameBuffer(void)
     printf("\n Test 13: Ensure we can utilize the full buffer size when frames removed during write");
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityHigh);
     WriteTestFrame2(ncpBuffer, NcpFrameBuffer::kPriorityLow);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh), "InFrameBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityHigh);
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyAndRemoveFrame2(ncpBuffer);
     SuccessOrQuit(ncpBuffer.InFrameFeedData(buffer, sizeof(buffer) - 4), "InFrameFeedData() failed.");
@@ -800,7 +800,7 @@ void TestNcpFrameBuffer(void)
     // Repeat the test with a low priority buffer write
     WriteTestFrame1(ncpBuffer, NcpFrameBuffer::kPriorityHigh);
     WriteTestFrame2(ncpBuffer, NcpFrameBuffer::kPriorityLow);
-    SuccessOrQuit(ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityLow), "InFrameBegin() failed.");
+    ncpBuffer.InFrameBegin(NcpFrameBuffer::kPriorityLow);
     VerifyAndRemoveFrame1(ncpBuffer);
     VerifyAndRemoveFrame2(ncpBuffer);
     SuccessOrQuit(ncpBuffer.InFrameFeedData(buffer, sizeof(buffer) - 4), "InFrameFeedData() failed.");
@@ -821,7 +821,7 @@ void TestNcpFrameBuffer(void)
         printf("*");
         priority = ((j % 3) == 0) ? NcpFrameBuffer::kPriorityHigh : NcpFrameBuffer::kPriorityLow;
         index    = static_cast<uint16_t>(j % sizeof(sHexText));
-        SuccessOrQuit(ncpBuffer.InFrameBegin(priority), "InFrameBegin() failed");
+        ncpBuffer.InFrameBegin(priority);
         SuccessOrQuit(ncpBuffer.InFrameFeedData(sHexText, index), "InFrameFeedData() failed.");
         SuccessOrQuit(ncpBuffer.InFrameGetPosition(pos1), "InFrameGetPosition() failed");
         SuccessOrQuit(ncpBuffer.InFrameFeedData(sMysteryText, sizeof(sHexText) - index), "InFrameFeedData() failed.");
@@ -867,7 +867,7 @@ void TestNcpFrameBuffer(void)
         printf("*");
         priority = ((j % 3) == 0) ? NcpFrameBuffer::kPriorityHigh : NcpFrameBuffer::kPriorityLow;
         index    = static_cast<uint16_t>(j % sizeof(sHexText));
-        SuccessOrQuit(ncpBuffer.InFrameBegin(priority), "InFrameBegin() failed");
+        ncpBuffer.InFrameBegin(priority);
         SuccessOrQuit(ncpBuffer.InFrameFeedData(sHexText, index), "InFrameFeedData() failed.");
         SuccessOrQuit(ncpBuffer.InFrameGetPosition(pos1), "InFrameGetPosition() failed");
         SuccessOrQuit(ncpBuffer.InFrameFeedData(sMysteryText, sizeof(sHexText) - index), "InFrameFeedData() failed.");
@@ -951,7 +951,7 @@ otError WriteRandomFrame(uint32_t aLength, NcpFrameBuffer &aNcpBuffer, NcpFrameB
     CallbackContext oldContext = sContext;
     uint32_t        tail       = sFrameBufferTailIndex[priority];
 
-    SuccessOrExit(error = aNcpBuffer.InFrameBegin(aPriority));
+    aNcpBuffer.InFrameBegin(aPriority);
 
     while (aLength--)
     {