[core] make metadata (saved in Message) non-packed (#4195)

src/core/coap/coap.hpp

@@ -88,7 +88,6 @@ enum
  * This class implements metadata required for CoAP retransmission.
  *
  */
-OT_TOOL_PACKED_BEGIN
 class CoapMetadata
 {
     friend class CoapBase;
@@ -192,7 +191,7 @@ private:
     uint8_t               mRetransmissionCount;   ///< Number of retransmissions.
     bool                  mAcknowledged : 1;      ///< Information that request was acknowledged.
     bool                  mConfirmable : 1;       ///< Information that message is confirmable.
-} OT_TOOL_PACKED_END;
+};
 
 /**
  * This class implements CoAP resource handling.

src/core/net/dns_client.hpp

@@ -51,7 +51,6 @@ namespace Dns {
  * This class implements metadata required for DNS retransmission.
  *
  */
-OT_TOOL_PACKED_BEGIN
 class QueryMetadata
 {
     friend class Client;
@@ -143,7 +142,7 @@ private:
     Ip6::Address         mDestinationAddress;  ///< IPv6 address of the message destination.
     uint16_t             mDestinationPort;     ///< UDP port of the message destination.
     uint8_t              mRetransmissionCount; ///< Number of retransmissions.
-} OT_TOOL_PACKED_END;
+};
 
 /**
  * This class implements DNS client.

src/core/net/ip6_mpl.hpp

@@ -247,7 +247,6 @@ private:
  * This class represents metadata required for MPL retransmissions.
  *
  */
-OT_TOOL_PACKED_BEGIN
 class MplBufferedMessageMetadata
 {
 public:
@@ -426,7 +425,7 @@ private:
     uint8_t   mTransmissionCount;
     TimeMilli mTransmissionTime;
     uint8_t   mIntervalOffset;
-} OT_TOOL_PACKED_END;
+};
 
 /**
  * This class implements MPL message processing.

src/core/net/sntp_client.hpp

@@ -421,7 +421,6 @@ private:
  * This class implements metadata required for SNTP retransmission.
  *
  */
-OT_TOOL_PACKED_BEGIN
 class QueryMetadata
 {
     friend class Client;
@@ -513,7 +512,7 @@ private:
     Ip6::Address          mDestinationAddress;  ///< IPv6 address of the message destination.
     uint16_t              mDestinationPort;     ///< UDP port of the message destination.
     uint8_t               mRetransmissionCount; ///< Number of retransmissions.
-} OT_TOOL_PACKED_END;
+};
 
 /**
  * This class implements SNTP client.

src/core/thread/mle.hpp

@@ -360,7 +360,6 @@ private:
  * This class implements functionality required for delaying MLE responses.
  *
  */
-OT_TOOL_PACKED_BEGIN
 class DelayedResponseHeader
 {
 public:
@@ -461,7 +460,7 @@ public:
 private:
     Ip6::Address mDestination; ///< IPv6 address of the message destination.
     TimeMilli    mSendTime;    ///< Time when the message shall be sent.
-} OT_TOOL_PACKED_END;
+};
 
 /**
  * This class implements MLE functionality required by the Thread EndDevices, Router, and Leader roles.