log some message

connection.go

@@ -10,6 +10,11 @@ type Connection struct {
 	TX     chan<- *DataFrame
 	ID     ID
 	closed bool
+	logger Logger
+}
+
+func (c *Connection) SetLogger(logger Logger) {
+	c.logger = logger
 }
 
 func (c *Connection) Read(p []byte) (int, error) {
@@ -17,6 +22,7 @@ func (c *Connection) Read(p []byte) (int, error) {
 	if !ok {
 		return 0, c.Close()
 	}
+	c.logger.Trace("dataframe received: ", df)
 	return df.Read(p)
 }
 
@@ -37,11 +43,13 @@ func (c *Connection) Write(p []byte) (int, error) {
 	if err != nil {
 		return 0, err
 	}
+	c.logger.Trace("dataframe send: ", df)
 	c.TX <- df
 	return n, nil
 }
 
 func (c *Connection) Close() error {
+	defer c.logger.Tracef("connection closed")
 	var lock sync.Mutex
 	defer close(c.TX)
 	if !c.closed {

errors.go

@@ -0,0 +1,11 @@
+package tunnel
+
+import "fmt"
+
+type WrongDataFrameTypeError struct {
+	ShouldBe Type
+}
+
+func (w WrongDataFrameTypeError) Error() string {
+	return fmt.Sprintf("wrong dataframe type, should be %s(%d)", w.ShouldBe, w.ShouldBe)
+}

logger.go

@@ -0,0 +1,43 @@
+package tunnel
+
+type Logger interface {
+	Trace(args ...interface{})
+	Tracef(format string, args ...interface{})
+
+	Debug(args ...interface{})
+	Debugf(format string, args ...interface{})
+
+	Info(args ...interface{})
+	Infof(format string, args ...interface{})
+
+	Error(args ...interface{})
+	Errorf(format string, args ...interface{})
+
+	Fatal(args ...interface{})
+	Fatalf(format string, args ...interface{})
+
+	Panic(args ...interface{})
+	Panicf(format string, args ...interface{})
+}
+
+type logger struct{}
+
+func (l *logger) Trace(args ...interface{})
+func (l *logger) Tracef(format string, args ...interface{})
+
+func (l *logger) Debug(args ...interface{})
+func (l *logger) Debugf(format string, args ...interface{})
+
+func (l *logger) Info(args ...interface{})
+func (l *logger) Infof(format string, args ...interface{})
+
+func (l *logger) Error(args ...interface{})
+func (l *logger) Errorf(format string, args ...interface{})
+
+func (l *logger) Fatal(args ...interface{})
+func (l *logger) Fatalf(format string, args ...interface{})
+
+func (l *logger) Panic(args ...interface{})
+func (l *logger) Panicf(format string, args ...interface{})
+
+var DefaultLogger = &logger{}

manager.go

@@ -1,7 +1,6 @@
 package tunnel
 
 import (
-	"errors"
 	"io"
 )
 
@@ -14,6 +13,7 @@ type Manager struct {
 	closed        chan bool
 	newConnection chan *Connection
 	delConnection chan *Connection
+	logger        Logger
 }
 
 func NewManager(tun io.ReadWriter) *Manager {
@@ -25,22 +25,31 @@ func NewManager(tun io.ReadWriter) *Manager {
 		accept:        make(chan *DataFrame, 1024),
 		newConnection: make(chan *Connection),
 		delConnection: make(chan *Connection),
+		logger:        DefaultLogger,
 	}
 }
 
+func (m *Manager) SetLogger(logger Logger) {
+	m.logger = logger
+}
+
 func (m *Manager) Run() {
+	m.logger.Debug("manager run")
 	onReceiveQueue := make(chan bool)
 	for {
 		select {
 		case <-m.closed:
 			return
 		case df := <-m.incoming:
+			m.logger.Trace("dataframe->tunnel: ", df)
 			go df.Encode(m.Tunnel)
 		case connection := <-m.newConnection:
 			m.Connections[connection.ID] = connection
+			m.logger.Tracef("connection '%s' registered", connection.ID)
 		case connection := <-m.delConnection:
 			connection.Close()
 			delete(m.Connections, connection.ID)
+			m.logger.Tracef("connection '%s' unregistered", connection.ID)
 		case onReceiveQueue <- true:
 			go m.onReceive(onReceiveQueue)
 		}
@@ -53,6 +62,8 @@ func (m *Manager) onReceive(ch chan bool) {
 	if err := df.Decode(m.Tunnel); err != nil {
 		return
 	}
+	m.logger.Trace("dataframe<-tunnel: ", df)
+
 	switch df.Type {
 	case TypeRequest:
 		m.accept <- df
@@ -76,16 +87,16 @@ func (m *Manager) Connect() (*Connection, error) {
 		Type: TypeRequest,
 	}
 	connection := &Connection{
-		ID: df.ID,
+		ID:     df.ID,
-		TX: m.incoming,
+		TX:     m.incoming,
+		logger: DefaultLogger,
 	}
 	m.newConnection <- connection
 	m.incoming <- df
 
 	df = <-connection.RX
 	if df.Type != TypeConnected {
-
+		return nil, WrongDataFrameTypeError{ShouldBe: TypeConnected}
-		return nil, errors.New("failed to connect")
 	}
 	return connection, nil
 }
@@ -93,11 +104,12 @@ func (m *Manager) Connect() (*Connection, error) {
 func (m *Manager) Accept() (*Connection, error) {
 	df := <-m.accept
 	if df.Type != TypeRequest {
-		return nil, errors.New("failed to accept")
+		return nil, WrongDataFrameTypeError{ShouldBe: TypeRequest}
 	}
 	connection := &Connection{
-		ID: df.ID,
+		ID:     df.ID,
-		TX: m.incoming,
+		TX:     m.incoming,
+		logger: DefaultLogger,
 	}
 	m.newConnection <- connection
 

types.go

@@ -9,3 +9,17 @@ func NewID() ID {
 }
 
 type Type uint8
+
+func (t Type) String() string {
+	switch t {
+	case TypeNormal:
+		return "normal"
+	case TypeRequest:
+		return "request"
+	case TypeConnected:
+		return "connected"
+	case TypeClosed:
+		return "closed"
+	}
+	return "invalid"
+}