diff --git a/cmd/main.go b/cmd/main.go
index 7abe26c..6d6d7c5 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -1,6 +1,5 @@
 package main
 
-import "C"
 import (
 	"flag"
 	"fmt"
diff --git a/component/stats/session/session.go b/component/stats/session/session.go
index 02d7b6d..4320a8d 100644
--- a/component/stats/session/session.go
+++ b/component/stats/session/session.go
@@ -10,7 +10,6 @@ import (
 	"sync/atomic"
 
 	"github.com/xjasonlyu/tun2socks/common/queue"
-	"github.com/xjasonlyu/tun2socks/component/stats"
 	C "github.com/xjasonlyu/tun2socks/constant"
 	"github.com/xjasonlyu/tun2socks/log"
 )
@@ -28,7 +27,7 @@ type simpleSessionStater struct {
 	completedSessionQueue *queue.Queue
 }
 
-func NewSimpleSessionStater() stats.SessionStater {
+func NewSimpleSessionStater() *simpleSessionStater {
 	return &simpleSessionStater{
 		completedSessionQueue: queue.New(maxCompletedSessions),
 	}
@@ -36,21 +35,21 @@ func NewSimpleSessionStater() stats.SessionStater {
 
 func (s *simpleSessionStater) sessionStatsHandler(resp http.ResponseWriter, req *http.Request) {
 	// Slice of active sessions
-	var activeSessions []*stats.Session
+	var activeSessions []*C.Session
 	s.activeSessionMap.Range(func(key, value interface{}) bool {
-		activeSessions = append(activeSessions, value.(*stats.Session))
+		activeSessions = append(activeSessions, value.(*C.Session))
 		return true
 	})
 
 	// Slice of completed sessions
-	var completedSessions []*stats.Session
+	var completedSessions []*C.Session
 	for _, item := range s.completedSessionQueue.Copy() {
-		if sess, ok := item.(*stats.Session); ok {
+		if sess, ok := item.(*C.Session); ok {
 			completedSessions = append(completedSessions, sess)
 		}
 	}
 
-	tablePrint := func(w io.Writer, sessions []*stats.Session) {
+	tablePrint := func(w io.Writer, sessions []*C.Session) {
 		// Sort by session start time.
 		sort.Slice(sessions, func(i, j int) bool {
 			return sessions[i].SessionStart.Sub(sessions[j].SessionStart) < 0
@@ -114,13 +113,13 @@ func (s *simpleSessionStater) Stop() error {
 	return s.server.Close()
 }
 
-func (s *simpleSessionStater) AddSession(key interface{}, session *stats.Session) {
+func (s *simpleSessionStater) AddSession(key interface{}, session *C.Session) {
 	s.activeSessionMap.Store(key, session)
 }
 
-func (s *simpleSessionStater) GetSession(key interface{}) *stats.Session {
+func (s *simpleSessionStater) GetSession(key interface{}) *C.Session {
 	if sess, ok := s.activeSessionMap.Load(key); ok {
-		return sess.(*stats.Session)
+		return sess.(*C.Session)
 	}
 	return nil
 }
diff --git a/component/stats/stats.go b/component/stats/stats.go
index a56ffa1..095798d 100644
--- a/component/stats/stats.go
+++ b/component/stats/stats.go
@@ -1,102 +1,13 @@
 package stats
 
 import (
-	"net"
-	"sync"
-	"sync/atomic"
-	"time"
+	C "github.com/xjasonlyu/tun2socks/constant"
 )
 
 type SessionStater interface {
 	Start() error
 	Stop() error
-	AddSession(key interface{}, session *Session)
-	GetSession(key interface{}) *Session
+	AddSession(key interface{}, session *C.Session)
+	GetSession(key interface{}) *C.Session
 	RemoveSession(key interface{})
 }
-
-type Session struct {
-	Process       string
-	Network       string
-	DialerAddr    string
-	ClientAddr    string
-	TargetAddr    string
-	UploadBytes   int64
-	DownloadBytes int64
-	SessionStart  time.Time
-	SessionClose  time.Time
-}
-
-// Track SessionConn
-type SessionConn struct {
-	net.Conn
-	once    sync.Once
-	session *Session
-}
-
-func NewSessionConn(conn net.Conn, session *Session) net.Conn {
-	return &SessionConn{
-		Conn:    conn,
-		session: session,
-	}
-}
-
-func (c *SessionConn) Read(b []byte) (n int, err error) {
-	n, err = c.Conn.Read(b)
-	if n > 0 {
-		atomic.AddInt64(&c.session.DownloadBytes, int64(n))
-	}
-	return
-}
-
-func (c *SessionConn) Write(b []byte) (n int, err error) {
-	n, err = c.Conn.Write(b)
-	if n > 0 {
-		atomic.AddInt64(&c.session.UploadBytes, int64(n))
-	}
-	return
-}
-
-func (c *SessionConn) Close() error {
-	c.once.Do(func() {
-		c.session.SessionClose = time.Now()
-	})
-	return c.Conn.Close()
-}
-
-// Track SessionPacketConn
-type SessionPacketConn struct {
-	net.PacketConn
-	once    sync.Once
-	session *Session
-}
-
-func NewSessionPacketConn(conn net.PacketConn, session *Session) net.PacketConn {
-	return &SessionPacketConn{
-		PacketConn: conn,
-		session:    session,
-	}
-}
-
-func (c *SessionPacketConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
-	n, addr, err = c.PacketConn.ReadFrom(b)
-	if n > 0 {
-		atomic.AddInt64(&c.session.DownloadBytes, int64(n))
-	}
-	return
-}
-
-func (c *SessionPacketConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
-	n, err = c.PacketConn.WriteTo(b, addr)
-	if n > 0 {
-		atomic.AddInt64(&c.session.UploadBytes, int64(n))
-	}
-	return
-}
-
-func (c *SessionPacketConn) Close() error {
-	c.once.Do(func() {
-		c.session.SessionClose = time.Now()
-	})
-	return c.PacketConn.Close()
-}
diff --git a/constant/session.go b/constant/session.go
new file mode 100644
index 0000000..1562f3a
--- /dev/null
+++ b/constant/session.go
@@ -0,0 +1,94 @@
+package constant
+
+import (
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type Session struct {
+	Process       string
+	Network       string
+	DialerAddr    string
+	ClientAddr    string
+	TargetAddr    string
+	UploadBytes   int64
+	DownloadBytes int64
+	SessionStart  time.Time
+	SessionClose  time.Time
+}
+
+// Track SessionConn
+type SessionConn struct {
+	net.Conn
+	once    sync.Once
+	session *Session
+}
+
+func NewSessionConn(conn net.Conn, session *Session) net.Conn {
+	return &SessionConn{
+		Conn:    conn,
+		session: session,
+	}
+}
+
+func (c *SessionConn) Read(b []byte) (n int, err error) {
+	n, err = c.Conn.Read(b)
+	if n > 0 {
+		atomic.AddInt64(&c.session.DownloadBytes, int64(n))
+	}
+	return
+}
+
+func (c *SessionConn) Write(b []byte) (n int, err error) {
+	n, err = c.Conn.Write(b)
+	if n > 0 {
+		atomic.AddInt64(&c.session.UploadBytes, int64(n))
+	}
+	return
+}
+
+func (c *SessionConn) Close() error {
+	c.once.Do(func() {
+		c.session.SessionClose = time.Now()
+	})
+	return c.Conn.Close()
+}
+
+// Track SessionPacketConn
+type SessionPacketConn struct {
+	net.PacketConn
+	once    sync.Once
+	session *Session
+}
+
+func NewSessionPacketConn(conn net.PacketConn, session *Session) net.PacketConn {
+	return &SessionPacketConn{
+		PacketConn: conn,
+		session:    session,
+	}
+}
+
+func (c *SessionPacketConn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
+	n, addr, err = c.PacketConn.ReadFrom(b)
+	if n > 0 {
+		atomic.AddInt64(&c.session.DownloadBytes, int64(n))
+	}
+	return
+}
+
+func (c *SessionPacketConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
+	n, err = c.PacketConn.WriteTo(b, addr)
+	if n > 0 {
+		atomic.AddInt64(&c.session.UploadBytes, int64(n))
+	}
+	return
+}
+
+func (c *SessionPacketConn) Close() error {
+	c.once.Do(func() {
+		c.session.SessionClose = time.Now()
+	})
+	return c.PacketConn.Close()
+}
diff --git a/proxy/tcp.go b/proxy/tcp.go
index d818bd7..42400d2 100644
--- a/proxy/tcp.go
+++ b/proxy/tcp.go
@@ -11,6 +11,7 @@ import (
 	"github.com/xjasonlyu/tun2socks/common/pool"
 	"github.com/xjasonlyu/tun2socks/component/dns"
 	"github.com/xjasonlyu/tun2socks/component/stats"
+	C "github.com/xjasonlyu/tun2socks/constant"
 	"github.com/xjasonlyu/tun2socks/core"
 	"github.com/xjasonlyu/tun2socks/log"
 )
@@ -104,7 +105,7 @@ func (h *tcpHandler) Handle(conn net.Conn, target *net.TCPAddr) error {
 	// Get name of the process.
 	var process = lsof.GetProcessName(localConn.LocalAddr())
 	if h.sessionStater != nil {
-		sess := &stats.Session{
+		sess := &C.Session{
 			Process:       process,
 			Network:       localConn.LocalAddr().Network(),
 			DialerAddr:    remoteConn.LocalAddr().String(),
@@ -116,7 +117,7 @@ func (h *tcpHandler) Handle(conn net.Conn, target *net.TCPAddr) error {
 		}
 		h.sessionStater.AddSession(localConn, sess)
 
-		remoteConn = stats.NewSessionConn(remoteConn, sess)
+		remoteConn = C.NewSessionConn(remoteConn, sess)
 	}
 
 	// Set keepalive
diff --git a/proxy/udp.go b/proxy/udp.go
index ffe387e..3530f92 100644
--- a/proxy/udp.go
+++ b/proxy/udp.go
@@ -11,6 +11,7 @@ import (
 	"github.com/xjasonlyu/tun2socks/common/pool"
 	"github.com/xjasonlyu/tun2socks/component/dns"
 	"github.com/xjasonlyu/tun2socks/component/stats"
+	C "github.com/xjasonlyu/tun2socks/constant"
 	"github.com/xjasonlyu/tun2socks/core"
 	"github.com/xjasonlyu/tun2socks/log"
 )
@@ -82,7 +83,7 @@ func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
 	// Get name of the process.
 	var process = lsof.GetProcessName(conn.LocalAddr())
 	if h.sessionStater != nil {
-		sess := &stats.Session{
+		sess := &C.Session{
 			Process:       process,
 			Network:       conn.LocalAddr().Network(),
 			DialerAddr:    remoteConn.LocalAddr().String(),
@@ -94,7 +95,7 @@ func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
 		}
 		h.sessionStater.AddSession(conn, sess)
 
-		remoteConn = stats.NewSessionPacketConn(remoteConn, sess)
+		remoteConn = C.NewSessionPacketConn(remoteConn, sess)
 	}
 
 	h.remoteAddrMap.Store(conn, remoteAddr)