use less memory by structs

dtls/server/config.go

@@ -52,13 +52,13 @@ var DefaultConfig = func() Config {
 }()
 
 type Config struct {
+	CreateInactivityMonitor func() udpClient.InactivityMonitor
+	GetMID                  GetMIDFunc
+	Handler                 HandlerFunc
+	OnNewConn               OnNewConnFunc
 	config.Common[*udpClient.Conn]
-	CreateInactivityMonitor        func() udpClient.InactivityMonitor
-	GetMID                         GetMIDFunc
-	Handler                        HandlerFunc
-	OnNewConn                      OnNewConnFunc
-	TransmissionNStart             uint32
 	TransmissionAcknowledgeTimeout time.Duration
+	TransmissionNStart             uint32
 	TransmissionMaxRetransmit      uint32
 	MTU                            uint16
 }

dtls/server/server.go

@@ -24,12 +24,12 @@ type Listener interface {
 }
 
 type Server struct {
+	cfg    *Config
 	ctx    context.Context
 	cancel context.CancelFunc
-	cfg    *Config
 
-	listenMutex sync.Mutex
 	listen      Listener
+	listenMutex sync.Mutex
 }
 
 // A Option sets options such as credentials, codec and keepalive parameters, etc.

dtls/server/session.go

@@ -17,22 +17,15 @@ import (
 type EventFunc = func()
 
 type Session struct {
-	onClose []EventFunc
-
-	ctx atomic.Value // TODO: change to atomic.Pointer[context.Context] for go1.19
-
-	cancel     context.CancelFunc
-	connection *coapNet.Conn
-
-	done chan struct{}
-
-	mutex sync.Mutex
-
+	ctx            atomic.Value // TODO: change to atomic.Pointer[context.Context] for go1.19
+	cancel         context.CancelFunc
+	connection     *coapNet.Conn
+	done           chan struct{}
+	onClose        []EventFunc
+	mutex          sync.Mutex
 	maxMessageSize uint32
-
-	mtu uint16
-
-	closeSocket bool
+	mtu            uint16
+	closeSocket    bool
 }
 
 func NewSession(

message/encodeDecodeUint32_test.go

@@ -12,8 +12,8 @@ func TestEncodeUint32(t *testing.T) {
 	}
 	tests := []struct {
 		name    string
-		args    args
 		want    int
+		args    args
 		wantErr bool
 	}{
 		{

message/message.go

@@ -10,14 +10,12 @@ import (
 const MaxTokenSize = 8
 
 type Message struct {
-	Token   Token
-	Options Options
-	Code    codes.Code
-	Payload []byte
-
-	// For DTLS and UDP messages
-	MessageID int32 // uint16 is valid, all other values are invalid, -1 is used for unset
-	Type      Type  // uint8 is valid, all other values are invalid, -1 is used for unset
+	Token     Token
+	Options   Options
+	Payload   []byte
+	MessageID int32
+	Code      codes.Code
+	Type      Type
 }
 
 func (r *Message) String() string {

message/options_test.go

@@ -90,8 +90,8 @@ func TestGetPathBufferSize(t *testing.T) {
 	tests := []struct {
 		name    string
 		args    args
-		wantErr bool
 		want    string
+		wantErr bool
 	}{
 		{
 			name: "Empty",

message/pool/message.go

@@ -23,19 +23,16 @@ type Decoder interface {
 }
 
 type Message struct {
-	// Context context of request.
 	ctx             context.Context
-	msg             message.Message
-	hijacked        atomic.Bool
-	isModified      bool
+	body            io.ReadSeeker
 	valueBuffer     []byte
 	origValueBuffer []byte
-	body            io.ReadSeeker
-	sequence        uint64
-
-	// local vars
 	bufferUnmarshal []byte
 	bufferMarshal   []byte
+	msg             message.Message
+	hijacked        atomic.Bool
+	sequence        uint64
+	isModified      bool
 }
 
 const valueBufferSize = 256
@@ -575,6 +572,10 @@ func (r *Message) Clone(msg *Message) error {
 		if err != nil {
 			return err
 		}
+		_, err = r.body.Seek(0, io.SeekStart)
+		if err != nil {
+			return err
+		}
 		_, err = io.Copy(buf, r.Body())
 		if err != nil {
 			var errs *multierror.Error

message/pool/message_test.go

@@ -20,8 +20,8 @@ func TestMessageSetPath(t *testing.T) {
 	tests := []struct {
 		name    string
 		args    args
-		wantErr bool
 		want    string
+		wantErr bool
 	}{
 		{
 			name:    "Empty",

message/pool/pool.go

@@ -9,8 +9,6 @@ import (
 )
 
 type Pool struct {
-	// This field needs to be the first in the struct to ensure proper word alignment on 32-bit platforms.
-	// See: https://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	currentMessagesInPool atomic.Int64
 	messagePool           sync.Pool
 	maxNumMessages        uint32

mux/router.go

@@ -41,18 +41,17 @@ func (f HandlerFunc) ServeCOAP(w ResponseWriter, r *Message) {
 // with same name.
 // Router is also safe for concurrent access from multiple goroutines.
 type Router struct {
-	middlewares []MiddlewareFunc
-	errors      ErrorFunc
-
 	m              *sync.RWMutex
+	errors         ErrorFunc
 	defaultHandler Handler          // guarded by m
 	z              map[string]Route // guarded by m
+	middlewares    []MiddlewareFunc
 }
 
 type Route struct {
 	h            Handler
-	pattern      string
 	regexMatcher *routeRegexp
+	pattern      string
 }
 
 func (route *Route) GetRouteRegexp() (string, error) {