feat: add headless mode support for SSH -N connections

- use s.lifecycle.GetConnection().Wait() to block until SSH connection closes
- Prevent premature session closure in headless mode

In headless mode (ssh -N), there's no channel interaction to block on,
so the session would immediately return and close. Now blocking on
conn.Wait() keeps the session alive until the client disconnects.

internal/grpc/client/client.go

@@ -263,7 +263,7 @@ func (c *Client) handleSlugChange(subscribe grpc.BidiStreamingClient[proto.Node,
 		}, "slug change failure response")
 	}
 
-	userSession.Interaction().Redraw()
+	userSession.GetInteraction().Redraw()
 	return c.sendNode(subscribe, &proto.Node{
 		Type: proto.EventType_SLUG_CHANGE_RESPONSE,
 		Payload: &proto.Node_SlugEventResponse{
@@ -321,7 +321,7 @@ func (c *Client) handleTerminateSession(subscribe grpc.BidiStreamingClient[proto
 		}, "terminate session fetch failed")
 	}
 
-	if err = userSession.Lifecycle().Close(); err != nil {
+	if err = userSession.GetLifecycle().Close(); err != nil {
 		return c.sendNode(subscribe, &proto.Node{
 			Type: proto.EventType_TERMINATE_SESSION,
 			Payload: &proto.Node_TerminateSessionEventResponse{

internal/port/port.go

@@ -13,7 +13,7 @@ type Manager interface {
 	AddPortRange(startPort, endPort uint16) error
 	GetUnassignedPort() (uint16, bool)
 	SetPortStatus(port uint16, assigned bool) error
-	ClaimPort(port uint16) (claimed bool)
+	GetPortStatus(port uint16) (bool, bool)
 }
 
 type manager struct {
@@ -74,6 +74,7 @@ func (pm *manager) GetUnassignedPort() (uint16, bool) {
 
 	for _, port := range pm.sortedPorts {
 		if !pm.ports[port] {
+			pm.ports[port] = true
 			return port, true
 		}
 	}
@@ -88,21 +89,10 @@ func (pm *manager) SetPortStatus(port uint16, assigned bool) error {
 	return nil
 }
 
-func (pm *manager) ClaimPort(port uint16) (claimed bool) {
-	pm.mu.Lock()
-	defer pm.mu.Unlock()
+func (pm *manager) GetPortStatus(port uint16) (bool, bool) {
+	pm.mu.RLock()
+	defer pm.mu.RUnlock()
 
 	status, exists := pm.ports[port]
-
-	if exists && status {
-		return false
-	}
-
-	if !exists {
-		pm.ports[port] = true
-		return true
-	}
-
-	pm.ports[port] = true
-	return true
+	return status, exists
 }

server/http.go

@@ -335,8 +335,8 @@ func (hs *httpServer) handler(conn net.Conn) {
 	return
 }
 
-func forwardRequest(cw HTTPWriter, initialRequest RequestHeaderManager, sshSession session.Session) {
-	payload := sshSession.Forwarder().CreateForwardedTCPIPPayload(cw.GetRemoteAddr())
+func forwardRequest(cw HTTPWriter, initialRequest RequestHeaderManager, sshSession *session.SSHSession) {
+	payload := sshSession.GetForwarder().CreateForwardedTCPIPPayload(cw.GetRemoteAddr())
 
 	type channelResult struct {
 		channel ssh.Channel
@@ -346,7 +346,7 @@ func forwardRequest(cw HTTPWriter, initialRequest RequestHeaderManager, sshSessi
 	resultChan := make(chan channelResult, 1)
 
 	go func() {
-		channel, reqs, err := sshSession.Lifecycle().Connection().OpenChannel("forwarded-tcpip", payload)
+		channel, reqs, err := sshSession.GetLifecycle().GetConnection().OpenChannel("forwarded-tcpip", payload)
 		resultChan <- channelResult{channel, reqs, err}
 	}()
 
@@ -357,14 +357,14 @@ func forwardRequest(cw HTTPWriter, initialRequest RequestHeaderManager, sshSessi
 	case result := <-resultChan:
 		if result.err != nil {
 			log.Printf("Failed to open forwarded-tcpip channel: %v", result.err)
-			sshSession.Forwarder().WriteBadGatewayResponse(cw.GetWriter())
+			sshSession.GetForwarder().WriteBadGatewayResponse(cw.GetWriter())
 			return
 		}
 		channel = result.channel
 		reqs = result.reqs
 	case <-time.After(5 * time.Second):
 		log.Printf("Timeout opening forwarded-tcpip channel")
-		sshSession.Forwarder().WriteBadGatewayResponse(cw.GetWriter())
+		sshSession.GetForwarder().WriteBadGatewayResponse(cw.GetWriter())
 		return
 	}
 
@@ -390,6 +390,6 @@ func forwardRequest(cw HTTPWriter, initialRequest RequestHeaderManager, sshSessi
 		return
 	}
 
-	sshSession.Forwarder().HandleConnection(cw, channel, cw.GetRemoteAddr())
+	sshSession.GetForwarder().HandleConnection(cw, channel, cw.GetRemoteAddr())
 	return
 }

session/forwarder/forwarder.go

@@ -30,50 +30,50 @@ func copyWithBuffer(dst io.Writer, src io.Reader) (written int64, err error) {
 	return io.CopyBuffer(dst, src, buf)
 }
 
-type forwarder struct {
+type Forwarder struct {
 	listener      net.Listener
 	tunnelType    types.TunnelType
 	forwardedPort uint16
-	slug          slug.Slug
+	slugManager   slug.Manager
 	lifecycle     Lifecycle
 }
 
-func New(slug slug.Slug) Forwarder {
-	return &forwarder{
+func NewForwarder(slugManager slug.Manager) *Forwarder {
+	return &Forwarder{
 		listener:      nil,
-		tunnelType:    types.UNKNOWN,
+		tunnelType:    "",
 		forwardedPort: 0,
-		slug:          slug,
+		slugManager:   slugManager,
 		lifecycle:     nil,
 	}
 }
 
 type Lifecycle interface {
-	Connection() ssh.Conn
+	GetConnection() ssh.Conn
 }
 
-type Forwarder interface {
+type ForwardingController interface {
+	AcceptTCPConnections()
 	SetType(tunnelType types.TunnelType)
-	SetLifecycle(lifecycle Lifecycle)
+	GetTunnelType() types.TunnelType
+	GetForwardedPort() uint16
 	SetForwardedPort(port uint16)
 	SetListener(listener net.Listener)
-	Listener() net.Listener
-	TunnelType() types.TunnelType
-	ForwardedPort() uint16
+	GetListener() net.Listener
+	Close() error
 	HandleConnection(dst io.ReadWriter, src ssh.Channel, remoteAddr net.Addr)
+	SetLifecycle(lifecycle Lifecycle)
 	CreateForwardedTCPIPPayload(origin net.Addr) []byte
 	WriteBadGatewayResponse(dst io.Writer)
-	AcceptTCPConnections()
-	Close() error
 }
 
-func (f *forwarder) SetLifecycle(lifecycle Lifecycle) {
+func (f *Forwarder) SetLifecycle(lifecycle Lifecycle) {
 	f.lifecycle = lifecycle
 }
 
-func (f *forwarder) AcceptTCPConnections() {
+func (f *Forwarder) AcceptTCPConnections() {
 	for {
-		conn, err := f.Listener().Accept()
+		conn, err := f.GetListener().Accept()
 		if err != nil {
 			if errors.Is(err, net.ErrClosed) {
 				return
@@ -100,7 +100,7 @@ func (f *forwarder) AcceptTCPConnections() {
 		resultChan := make(chan channelResult, 1)
 
 		go func() {
-			channel, reqs, err := f.lifecycle.Connection().OpenChannel("forwarded-tcpip", payload)
+			channel, reqs, err := f.lifecycle.GetConnection().OpenChannel("forwarded-tcpip", payload)
 			resultChan <- channelResult{channel, reqs, err}
 		}()
 
@@ -130,7 +130,7 @@ func (f *forwarder) AcceptTCPConnections() {
 	}
 }
 
-func (f *forwarder) HandleConnection(dst io.ReadWriter, src ssh.Channel, remoteAddr net.Addr) {
+func (f *Forwarder) HandleConnection(dst io.ReadWriter, src ssh.Channel, remoteAddr net.Addr) {
 	defer func() {
 		_, err := io.Copy(io.Discard, src)
 		if err != nil {
@@ -174,31 +174,31 @@ func (f *forwarder) HandleConnection(dst io.ReadWriter, src ssh.Channel, remoteA
 	wg.Wait()
 }
 
-func (f *forwarder) SetType(tunnelType types.TunnelType) {
+func (f *Forwarder) SetType(tunnelType types.TunnelType) {
 	f.tunnelType = tunnelType
 }
 
-func (f *forwarder) TunnelType() types.TunnelType {
+func (f *Forwarder) GetTunnelType() types.TunnelType {
 	return f.tunnelType
 }
 
-func (f *forwarder) ForwardedPort() uint16 {
+func (f *Forwarder) GetForwardedPort() uint16 {
 	return f.forwardedPort
 }
 
-func (f *forwarder) SetForwardedPort(port uint16) {
+func (f *Forwarder) SetForwardedPort(port uint16) {
 	f.forwardedPort = port
 }
 
-func (f *forwarder) SetListener(listener net.Listener) {
+func (f *Forwarder) SetListener(listener net.Listener) {
 	f.listener = listener
 }
 
-func (f *forwarder) Listener() net.Listener {
+func (f *Forwarder) GetListener() net.Listener {
 	return f.listener
 }
 
-func (f *forwarder) WriteBadGatewayResponse(dst io.Writer) {
+func (f *Forwarder) WriteBadGatewayResponse(dst io.Writer) {
 	_, err := dst.Write(types.BadGatewayResponse)
 	if err != nil {
 		log.Printf("failed to write Bad Gateway response: %v", err)
@@ -206,20 +206,20 @@ func (f *forwarder) WriteBadGatewayResponse(dst io.Writer) {
 	}
 }
 
-func (f *forwarder) Close() error {
-	if f.Listener() != nil {
+func (f *Forwarder) Close() error {
+	if f.GetListener() != nil {
 		return f.listener.Close()
 	}
 	return nil
 }
 
-func (f *forwarder) CreateForwardedTCPIPPayload(origin net.Addr) []byte {
+func (f *Forwarder) CreateForwardedTCPIPPayload(origin net.Addr) []byte {
 	var buf bytes.Buffer
 
 	host, originPort := parseAddr(origin.String())
 
 	writeSSHString(&buf, "localhost")
-	err := binary.Write(&buf, binary.BigEndian, uint32(f.ForwardedPort()))
+	err := binary.Write(&buf, binary.BigEndian, uint32(f.GetForwardedPort()))
 	if err != nil {
 		log.Printf("Failed to write string to buffer: %v", err)
 		return nil

session/handler.go

@@ -15,7 +15,7 @@ import (
 
 var blockedReservedPorts = []uint16{1080, 1433, 1521, 1900, 2049, 3306, 3389, 5432, 5900, 6379, 8080, 8443, 9000, 9200, 27017}
 
-func (s *session) HandleGlobalRequest(GlobalRequest <-chan *ssh.Request) {
+func (s *SSHSession) HandleGlobalRequest(GlobalRequest <-chan *ssh.Request) {
 	for req := range GlobalRequest {
 		switch req.Type {
 		case "shell", "pty-req":
@@ -56,170 +56,228 @@ func (s *session) HandleGlobalRequest(GlobalRequest <-chan *ssh.Request) {
 	}
 }
 
-func (s *session) HandleTCPIPForward(req *ssh.Request) {
+func (s *SSHSession) HandleTCPIPForward(req *ssh.Request) {
 	log.Println("Port forwarding request detected")
 
-	fail := func(msg string) {
-		log.Println(msg)
-		if err := req.Reply(false, nil); err != nil {
-			log.Println("Failed to reply to request:", err)
-			return
-		}
-		if err := s.lifecycle.Close(); err != nil {
-			log.Printf("failed to close session: %v", err)
-		}
-	}
-
 	reader := bytes.NewReader(req.Payload)
 
 	addr, err := readSSHString(reader)
 	if err != nil {
-		fail(fmt.Sprintf("Failed to read address from payload: %v", err))
+		log.Println("Failed to read address from payload:", err)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
 		return
 	}
 
 	var rawPortToBind uint32
-	if err = binary.Read(reader, binary.BigEndian, &rawPortToBind); err != nil {
-		fail(fmt.Sprintf("Failed to read port from payload: %v", err))
+	if err := binary.Read(reader, binary.BigEndian, &rawPortToBind); err != nil {
+		log.Println("Failed to read port from payload:", err)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
 		return
 	}
 
 	if rawPortToBind > 65535 {
-		fail(fmt.Sprintf("Port %d is larger than allowed port of 65535", rawPortToBind))
+		log.Printf("Port %d is larger than allowed port of 65535", rawPortToBind)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
 		return
 	}
 
 	portToBind := uint16(rawPortToBind)
 	if isBlockedPort(portToBind) {
-		fail(fmt.Sprintf("Port %d is blocked or restricted", portToBind))
+		log.Printf("Port %d is blocked or restricted", portToBind)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
 		return
 	}
 
-	switch portToBind {
-	case 80, 443:
+	if portToBind == 80 || portToBind == 443 {
 		s.HandleHTTPForward(req, portToBind)
-	default:
+		return
+	}
+	if portToBind == 0 {
+		unassign, success := portUtil.Default.GetUnassignedPort()
+		portToBind = unassign
+		if !success {
+			log.Println("No available port")
+			err := req.Reply(false, nil)
+			if err != nil {
+				log.Println("Failed to reply to request:", err)
+				return
+			}
+			err = s.lifecycle.Close()
+			if err != nil {
+				log.Printf("failed to close session: %v", err)
+			}
+			return
+		}
+	} else if isUse, isExist := portUtil.Default.GetPortStatus(portToBind); isExist && isUse {
+		log.Printf("Port %d is already in use or restricted", portToBind)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
+		return
+	}
+	err = portUtil.Default.SetPortStatus(portToBind, true)
+	if err != nil {
+		log.Println("Failed to set port status:", err)
+		return
+	}
+
 	s.HandleTCPForward(req, addr, portToBind)
 }
-}
-
-func (s *session) HandleHTTPForward(req *ssh.Request, portToBind uint16) {
-	fail := func(msg string, key *types.SessionKey) {
-		log.Println(msg)
-		if key != nil {
-			s.registry.Remove(*key)
-		}
-		if err := req.Reply(false, nil); err != nil {
-			log.Println("Failed to reply to request:", err)
-		}
-	}
 
+func (s *SSHSession) HandleHTTPForward(req *ssh.Request, portToBind uint16) {
 	slug := random.GenerateRandomString(20)
 	key := types.SessionKey{Id: slug, Type: types.HTTP}
 	if !s.registry.Register(key, s) {
-		fail(fmt.Sprintf("Failed to register client with slug: %s", slug), nil)
+		log.Printf("Failed to register client with slug: %s", slug)
+		err := req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
 		return
 	}
 
 	buf := new(bytes.Buffer)
 	err := binary.Write(buf, binary.BigEndian, uint32(portToBind))
 	if err != nil {
-		fail(fmt.Sprintf("Failed to write port to buffer: %v", err), &key)
+		log.Println("Failed to write port to buffer:", err)
+		s.registry.Remove(key)
+		err = req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
 		return
 	}
 	log.Printf("HTTP forwarding approved on port: %d", portToBind)
 
 	err = req.Reply(true, buf.Bytes())
 	if err != nil {
-		fail(fmt.Sprintf("Failed to reply to request: %v", err), &key)
+		log.Println("Failed to reply to request:", err)
+		s.registry.Remove(key)
+		err = req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
 		return
 	}
 
 	s.forwarder.SetType(types.HTTP)
 	s.forwarder.SetForwardedPort(portToBind)
-	s.slug.Set(slug)
+	s.slugManager.Set(slug)
 	s.lifecycle.SetStatus(types.RUNNING)
 }
 
-func (s *session) HandleTCPForward(req *ssh.Request, addr string, portToBind uint16) {
-	fail := func(msg string) {
-		log.Println(msg)
-		if err := req.Reply(false, nil); err != nil {
-			log.Println("Failed to reply to request:", err)
-			return
-		}
-		if err := s.lifecycle.Close(); err != nil {
-			log.Printf("failed to close session: %v", err)
-		}
-	}
-
-	cleanup := func(msg string, port uint16, listener net.Listener, key *types.SessionKey) {
-		log.Println(msg)
-		if key != nil {
-			s.registry.Remove(*key)
-		}
-		if port != 0 {
-			if setErr := portUtil.Default.SetPortStatus(port, false); setErr != nil {
-				log.Printf("Failed to reset port status: %v", setErr)
-			}
-		}
-		if listener != nil {
-			if closeErr := listener.Close(); closeErr != nil {
-				log.Printf("Failed to close listener: %v", closeErr)
-			}
-		}
-		if err := req.Reply(false, nil); err != nil {
-			log.Println("Failed to reply to request:", err)
-		}
-		_ = s.lifecycle.Close()
-	}
-
-	if portToBind == 0 {
-		unassigned, ok := portUtil.Default.GetUnassignedPort()
-		if !ok {
-			fail("No available port")
-			return
-		}
-		portToBind = unassigned
-	}
-
-	if claimed := portUtil.Default.ClaimPort(portToBind); !claimed {
-		fail(fmt.Sprintf("Port %d is already in use or restricted", portToBind))
-		return
-	}
-
+func (s *SSHSession) HandleTCPForward(req *ssh.Request, addr string, portToBind uint16) {
 	log.Printf("Requested forwarding on %s:%d", addr, portToBind)
 	listener, err := net.Listen("tcp", fmt.Sprintf("0.0.0.0:%d", portToBind))
 	if err != nil {
-		cleanup(fmt.Sprintf("Port %d is already in use or restricted", portToBind), portToBind, nil, nil)
+		log.Printf("Port %d is already in use or restricted", portToBind)
+		if setErr := portUtil.Default.SetPortStatus(portToBind, false); setErr != nil {
+			log.Printf("Failed to reset port status: %v", setErr)
+		}
+		err = req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		err = s.lifecycle.Close()
+		if err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
 		return
 	}
 
 	key := types.SessionKey{Id: fmt.Sprintf("%d", portToBind), Type: types.TCP}
 
 	if !s.registry.Register(key, s) {
-		cleanup(fmt.Sprintf("Failed to register TCP client with id: %s", key.Id), portToBind, listener, nil)
+		log.Printf("Failed to register TCP client with id: %s", key.Id)
+		if setErr := portUtil.Default.SetPortStatus(portToBind, false); setErr != nil {
+			log.Printf("Failed to reset port status: %v", setErr)
+		}
+		if closeErr := listener.Close(); closeErr != nil {
+			log.Printf("Failed to close listener: %s", closeErr)
+		}
+		err = req.Reply(false, nil)
+		if err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
+		_ = s.lifecycle.Close()
 		return
 	}
 
 	buf := new(bytes.Buffer)
 	err = binary.Write(buf, binary.BigEndian, uint32(portToBind))
 	if err != nil {
-		cleanup(fmt.Sprintf("Failed to write port to buffer: %v", err), portToBind, listener, &key)
+		log.Println("Failed to write port to buffer:", err)
+		s.registry.Remove(key)
+		if setErr := portUtil.Default.SetPortStatus(portToBind, false); setErr != nil {
+			log.Printf("Failed to reset port status: %v", setErr)
+		}
+		err = listener.Close()
+		if err != nil {
+			log.Printf("Failed to close listener: %s", err)
+			return
+		}
 		return
 	}
 
 	log.Printf("TCP forwarding approved on port: %d", portToBind)
 	err = req.Reply(true, buf.Bytes())
 	if err != nil {
-		cleanup(fmt.Sprintf("Failed to reply to request: %v", err), portToBind, listener, &key)
+		log.Println("Failed to reply to request:", err)
+		s.registry.Remove(key)
+		if setErr := portUtil.Default.SetPortStatus(portToBind, false); setErr != nil {
+			log.Printf("Failed to reset port status: %v", setErr)
+		}
+		err = listener.Close()
+		if err != nil {
+			log.Printf("Failed to close listener: %s", err)
+			return
+		}
 		return
 	}
 
 	s.forwarder.SetType(types.TCP)
 	s.forwarder.SetListener(listener)
 	s.forwarder.SetForwardedPort(portToBind)
-	s.slug.Set(key.Id)
+	s.slugManager.Set(key.Id)
 	s.lifecycle.SetStatus(types.RUNNING)
 	go s.forwarder.AcceptTCPConnections()
 }

session/interaction/interaction.go

@@ -23,34 +23,34 @@ import (
 
 type Lifecycle interface {
 	Close() error
-	User() string
+	GetUser() string
 }
 
 type SessionRegistry interface {
 	Update(user string, oldKey, newKey types.SessionKey) error
 }
 
-type Interaction interface {
-	Mode() types.Mode
+type Controller interface {
 	SetChannel(channel ssh.Channel)
 	SetLifecycle(lifecycle Lifecycle)
+	Start()
+	SetWH(w, h int)
+	Redraw()
 	SetSessionRegistry(registry SessionRegistry)
 	SetMode(m types.Mode)
-	SetWH(w, h int)
-	Start()
-	Redraw()
+	GetMode() types.Mode
 	Send(message string) error
 }
 
 type Forwarder interface {
 	Close() error
-	TunnelType() types.TunnelType
-	ForwardedPort() uint16
+	GetTunnelType() types.TunnelType
+	GetForwardedPort() uint16
 }
 
-type interaction struct {
+type Interaction struct {
 	channel         ssh.Channel
-	slug            slug.Slug
+	slugManager     slug.Manager
 	forwarder       Forwarder
 	lifecycle       Lifecycle
 	sessionRegistry SessionRegistry
@@ -60,22 +60,22 @@ type interaction struct {
 	mode            types.Mode
 }
 
-func (i *interaction) SetMode(m types.Mode) {
+func (i *Interaction) SetMode(m types.Mode) {
 	i.mode = m
 }
 
-func (i *interaction) Mode() types.Mode {
+func (i *Interaction) GetMode() types.Mode {
 	return i.mode
 }
 
-func (i *interaction) Send(message string) error {
+func (i *Interaction) Send(message string) error {
 	if i.channel != nil {
 		_, err := i.channel.Write([]byte(message))
 		return err
 	}
 	return nil
 }
-func (i *interaction) SetWH(w, h int) {
+func (i *Interaction) SetWH(w, h int) {
 	if i.program != nil {
 		i.program.Send(tea.WindowSizeMsg{
 			Width:  w,
@@ -103,14 +103,14 @@ type model struct {
 	commandList       list.Model
 	slugInput         textinput.Model
 	slugError         string
-	interaction       *interaction
+	interaction       *Interaction
 	width             int
 	height            int
 }
 
 func (m *model) getTunnelURL() string {
 	if m.tunnelType == types.HTTP {
-		return buildURL(m.protocol, m.interaction.slug.String(), m.domain)
+		return buildURL(m.protocol, m.interaction.slugManager.Get(), m.domain)
 	}
 	return fmt.Sprintf("tcp://%s:%d", m.domain, m.port)
 }
@@ -123,11 +123,11 @@ type keymap struct {
 
 type tickMsg time.Time
 
-func New(slug slug.Slug, forwarder Forwarder) Interaction {
+func NewInteraction(slugManager slug.Manager, forwarder Forwarder) *Interaction {
 	ctx, cancel := context.WithCancel(context.Background())
-	return &interaction{
+	return &Interaction{
 		channel:         nil,
-		slug:            slug,
+		slugManager:     slugManager,
 		forwarder:       forwarder,
 		lifecycle:       nil,
 		sessionRegistry: nil,
@@ -137,19 +137,19 @@ func New(slug slug.Slug, forwarder Forwarder) Interaction {
 	}
 }
 
-func (i *interaction) SetSessionRegistry(registry SessionRegistry) {
+func (i *Interaction) SetSessionRegistry(registry SessionRegistry) {
 	i.sessionRegistry = registry
 }
 
-func (i *interaction) SetLifecycle(lifecycle Lifecycle) {
+func (i *Interaction) SetLifecycle(lifecycle Lifecycle) {
 	i.lifecycle = lifecycle
 }
 
-func (i *interaction) SetChannel(channel ssh.Channel) {
+func (i *Interaction) SetChannel(channel ssh.Channel) {
 	i.channel = channel
 }
 
-func (i *interaction) Stop() {
+func (i *Interaction) Stop() {
 	if i.cancel != nil {
 		i.cancel()
 	}
@@ -242,8 +242,8 @@ func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				return m, tea.Batch(tea.ClearScreen, textinput.Blink)
 			case "enter":
 				inputValue := m.slugInput.Value()
-				if err := m.interaction.sessionRegistry.Update(m.interaction.lifecycle.User(), types.SessionKey{
-					Id:   m.interaction.slug.String(),
+				if err := m.interaction.sessionRegistry.Update(m.interaction.lifecycle.GetUser(), types.SessionKey{
+					Id:   m.interaction.slugManager.Get(),
 					Type: types.HTTP,
 				}, types.SessionKey{
 					Id:   inputValue,
@@ -285,7 +285,7 @@ func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 					if item.name == "slug" {
 						m.showingCommands = false
 						m.editingSlug = true
-						m.slugInput.SetValue(m.interaction.slug.String())
+						m.slugInput.SetValue(m.interaction.slugManager.Get())
 						m.slugInput.Focus()
 						return m, tea.Batch(tea.ClearScreen, textinput.Blink)
 					} else if item.name == "tunnel-type" {
@@ -317,7 +317,7 @@ func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
-func (i *interaction) Redraw() {
+func (i *Interaction) Redraw() {
 	if i.program != nil {
 		i.program.Send(tea.ClearScreen())
 	}
@@ -691,7 +691,7 @@ func (m *model) View() string {
 		MarginBottom(boxMargin).
 		Width(boxMaxWidth)
 
-	authenticatedUser := m.interaction.lifecycle.User()
+	authenticatedUser := m.interaction.lifecycle.GetUser()
 
 	userInfoStyle := lipgloss.NewStyle().
 		Foreground(lipgloss.Color("#FAFAFA")).
@@ -767,7 +767,7 @@ func (m *model) View() string {
 	return b.String()
 }
 
-func (i *interaction) Start() {
+func (i *Interaction) Start() {
 	if i.mode == types.HEADLESS {
 		return
 	}
@@ -779,8 +779,8 @@ func (i *interaction) Start() {
 		protocol = "https"
 	}
 
-	tunnelType := i.forwarder.TunnelType()
-	port := i.forwarder.ForwardedPort()
+	tunnelType := i.forwarder.GetTunnelType()
+	port := i.forwarder.GetForwardedPort()
 
 	items := []list.Item{
 		commandItem{name: "slug", desc: "Set custom subdomain"},

session/lifecycle/lifecycle.go

@@ -15,119 +15,115 @@ import (
 
 type Forwarder interface {
 	Close() error
-	TunnelType() types.TunnelType
-	ForwardedPort() uint16
+	GetTunnelType() types.TunnelType
+	GetForwardedPort() uint16
 }
 
 type SessionRegistry interface {
 	Remove(key types.SessionKey)
 }
 
-type lifecycle struct {
+type Lifecycle struct {
 	status          types.Status
 	conn            ssh.Conn
 	channel         ssh.Channel
 	forwarder       Forwarder
 	sessionRegistry SessionRegistry
-	slug            slug.Slug
+	slugManager     slug.Manager
 	startedAt       time.Time
 	user            string
 }
 
-func New(conn ssh.Conn, forwarder Forwarder, slugManager slug.Slug, user string) Lifecycle {
-	return &lifecycle{
+func NewLifecycle(conn ssh.Conn, forwarder Forwarder, slugManager slug.Manager, user string) *Lifecycle {
+	return &Lifecycle{
 		status:          types.INITIALIZING,
 		conn:            conn,
 		channel:         nil,
 		forwarder:       forwarder,
-		slug:            slugManager,
+		slugManager:     slugManager,
 		sessionRegistry: nil,
 		startedAt:       time.Now(),
 		user:            user,
 	}
 }
 
-func (l *lifecycle) SetSessionRegistry(registry SessionRegistry) {
+func (l *Lifecycle) SetSessionRegistry(registry SessionRegistry) {
 	l.sessionRegistry = registry
 }
 
-type Lifecycle interface {
-	Connection() ssh.Conn
-	Channel() ssh.Channel
-	User() string
+type SessionLifecycle interface {
+	Close() error
+	SetStatus(status types.Status)
+	GetConnection() ssh.Conn
+	GetChannel() ssh.Channel
+	GetUser() string
 	SetChannel(channel ssh.Channel)
 	SetSessionRegistry(registry SessionRegistry)
-	SetStatus(status types.Status)
 	IsActive() bool
 	StartedAt() time.Time
-	Close() error
 }
 
-func (l *lifecycle) User() string {
+func (l *Lifecycle) GetUser() string {
 	return l.user
 }
 
-func (l *lifecycle) Channel() ssh.Channel {
+func (l *Lifecycle) GetChannel() ssh.Channel {
 	return l.channel
 }
 
-func (l *lifecycle) SetChannel(channel ssh.Channel) {
+func (l *Lifecycle) SetChannel(channel ssh.Channel) {
 	l.channel = channel
 }
-func (l *lifecycle) Connection() ssh.Conn {
+func (l *Lifecycle) GetConnection() ssh.Conn {
 	return l.conn
 }
-func (l *lifecycle) SetStatus(status types.Status) {
+func (l *Lifecycle) SetStatus(status types.Status) {
 	l.status = status
 	if status == types.RUNNING && l.startedAt.IsZero() {
 		l.startedAt = time.Now()
 	}
 }
 
-func (l *lifecycle) Close() error {
-	var firstErr error
-	tunnelType := l.forwarder.TunnelType()
-
-	if err := l.forwarder.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
-		firstErr = err
+func (l *Lifecycle) Close() error {
+	err := l.forwarder.Close()
+	if err != nil && !errors.Is(err, net.ErrClosed) {
+		return err
 	}
 
 	if l.channel != nil {
-		if err := l.channel.Close(); err != nil && !errors.Is(err, io.EOF) && !errors.Is(err, net.ErrClosed) {
-			if firstErr == nil {
-				firstErr = err
-			}
+		err := l.channel.Close()
+		if err != nil && !errors.Is(err, io.EOF) {
+			return err
 		}
 	}
 
 	if l.conn != nil {
-		if err := l.conn.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
-			if firstErr == nil {
-				firstErr = err
-			}
+		err := l.conn.Close()
+		if err != nil && !errors.Is(err, net.ErrClosed) {
+			return err
 		}
 	}
 
-	clientSlug := l.slug.String()
-	key := types.SessionKey{
-		Id:   clientSlug,
-		Type: tunnelType,
-	}
+	clientSlug := l.slugManager.Get()
+	if clientSlug != "" && l.sessionRegistry.Remove != nil {
+		key := types.SessionKey{Id: clientSlug, Type: l.forwarder.GetTunnelType()}
 		l.sessionRegistry.Remove(key)
+	}
 
-	if tunnelType == types.TCP {
-		if err := portUtil.Default.SetPortStatus(l.forwarder.ForwardedPort(), false); err != nil && firstErr == nil {
-			firstErr = err
+	if l.forwarder.GetTunnelType() == types.TCP {
+		err = portUtil.Default.SetPortStatus(l.forwarder.GetForwardedPort(), false)
+		if err != nil {
+			return err
 		}
 	}
 
-	return firstErr
+	return nil
 }
 
-func (l *lifecycle) IsActive() bool {
+func (l *Lifecycle) IsActive() bool {
 	return l.status == types.RUNNING
 }
 
-func (l *lifecycle) StartedAt() time.Time {
+func (l *Lifecycle) StartedAt() time.Time {
 	return l.startedAt
 }

session/registry.go

@@ -9,27 +9,27 @@ import (
 type Key = types.SessionKey
 
 type Registry interface {
-	Get(key Key) (session Session, err error)
-	GetWithUser(user string, key Key) (session Session, err error)
+	Get(key Key) (session *SSHSession, err error)
+	GetWithUser(user string, key Key) (session *SSHSession, err error)
 	Update(user string, oldKey, newKey Key) error
-	Register(key Key, session Session) (success bool)
+	Register(key Key, session *SSHSession) (success bool)
 	Remove(key Key)
-	GetAllSessionFromUser(user string) []Session
+	GetAllSessionFromUser(user string) []*SSHSession
 }
 type registry struct {
 	mu        sync.RWMutex
-	byUser    map[string]map[Key]Session
+	byUser    map[string]map[Key]*SSHSession
 	slugIndex map[Key]string
 }
 
 func NewRegistry() Registry {
 	return &registry{
-		byUser:    make(map[string]map[Key]Session),
+		byUser:    make(map[string]map[Key]*SSHSession),
 		slugIndex: make(map[Key]string),
 	}
 }
 
-func (r *registry) Get(key Key) (session Session, err error) {
+func (r *registry) Get(key Key) (session *SSHSession, err error) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 
@@ -45,7 +45,7 @@ func (r *registry) Get(key Key) (session Session, err error) {
 	return client, nil
 }
 
-func (r *registry) GetWithUser(user string, key Key) (session Session, err error) {
+func (r *registry) GetWithUser(user string, key Key) (session *SSHSession, err error) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 
@@ -87,17 +87,17 @@ func (r *registry) Update(user string, oldKey, newKey Key) error {
 	delete(r.byUser[user], oldKey)
 	delete(r.slugIndex, oldKey)
 
-	client.Slug().Set(newKey.Id)
+	client.slugManager.Set(newKey.Id)
 	r.slugIndex[newKey] = user
 
 	if r.byUser[user] == nil {
-		r.byUser[user] = make(map[Key]Session)
+		r.byUser[user] = make(map[Key]*SSHSession)
 	}
 	r.byUser[user][newKey] = client
 	return nil
 }
 
-func (r *registry) Register(key Key, session Session) (success bool) {
+func (r *registry) Register(key Key, session *SSHSession) (success bool) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
@@ -105,9 +105,9 @@ func (r *registry) Register(key Key, session Session) (success bool) {
 		return false
 	}
 
-	userID := session.Lifecycle().User()
+	userID := session.lifecycle.GetUser()
 	if r.byUser[userID] == nil {
-		r.byUser[userID] = make(map[Key]Session)
+		r.byUser[userID] = make(map[Key]*SSHSession)
 	}
 
 	r.byUser[userID][key] = session
@@ -115,16 +115,16 @@ func (r *registry) Register(key Key, session Session) (success bool) {
 	return true
 }
 
-func (r *registry) GetAllSessionFromUser(user string) []Session {
+func (r *registry) GetAllSessionFromUser(user string) []*SSHSession {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 
 	m := r.byUser[user]
 	if len(m) == 0 {
-		return []Session{}
+		return []*SSHSession{}
 	}
 
-	sessions := make([]Session, 0, len(m))
+	sessions := make([]*SSHSession, 0, len(m))
 	for _, s := range m {
 		sessions = append(sessions, s)
 	}

session/session.go

@@ -14,6 +14,61 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
+type Session interface {
+	HandleGlobalRequest(ch <-chan *ssh.Request)
+	HandleTCPIPForward(req *ssh.Request)
+	HandleHTTPForward(req *ssh.Request, port uint16)
+	HandleTCPForward(req *ssh.Request, addr string, port uint16)
+}
+
+type SSHSession struct {
+	initialReq    <-chan *ssh.Request
+	sshReqChannel <-chan ssh.NewChannel
+	lifecycle     lifecycle.SessionLifecycle
+	interaction   interaction.Controller
+	forwarder     forwarder.ForwardingController
+	slugManager   slug.Manager
+	registry      Registry
+}
+
+func (s *SSHSession) GetLifecycle() lifecycle.SessionLifecycle {
+	return s.lifecycle
+}
+
+func (s *SSHSession) GetInteraction() interaction.Controller {
+	return s.interaction
+}
+
+func (s *SSHSession) GetForwarder() forwarder.ForwardingController {
+	return s.forwarder
+}
+
+func (s *SSHSession) GetSlugManager() slug.Manager {
+	return s.slugManager
+}
+
+func New(conn *ssh.ServerConn, forwardingReq <-chan *ssh.Request, sshChan <-chan ssh.NewChannel, sessionRegistry Registry, user string) *SSHSession {
+	slugManager := slug.NewManager()
+	forwarderManager := forwarder.NewForwarder(slugManager)
+	interactionManager := interaction.NewInteraction(slugManager, forwarderManager)
+	lifecycleManager := lifecycle.NewLifecycle(conn, forwarderManager, slugManager, user)
+
+	interactionManager.SetLifecycle(lifecycleManager)
+	forwarderManager.SetLifecycle(lifecycleManager)
+	interactionManager.SetSessionRegistry(sessionRegistry)
+	lifecycleManager.SetSessionRegistry(sessionRegistry)
+
+	return &SSHSession{
+		initialReq:    forwardingReq,
+		sshReqChannel: sshChan,
+		lifecycle:     lifecycleManager,
+		interaction:   interactionManager,
+		forwarder:     forwarderManager,
+		slugManager:   slugManager,
+		registry:      sessionRegistry,
+	}
+}
+
 type Detail struct {
 	ForwardingType string    `json:"forwarding_type,omitempty"`
 	Slug           string    `json:"slug,omitempty"`
@@ -22,90 +77,21 @@ type Detail struct {
 	StartedAt      time.Time `json:"started_at,omitempty"`
 }
 
-type Session interface {
-	HandleGlobalRequest(ch <-chan *ssh.Request)
-	HandleTCPIPForward(req *ssh.Request)
-	HandleHTTPForward(req *ssh.Request, port uint16)
-	HandleTCPForward(req *ssh.Request, addr string, port uint16)
-	Lifecycle() lifecycle.Lifecycle
-	Interaction() interaction.Interaction
-	Forwarder() forwarder.Forwarder
-	Slug() slug.Slug
-	Detail() *Detail
-	Start() error
-}
-
-type session struct {
-	initialReq  <-chan *ssh.Request
-	sshChan     <-chan ssh.NewChannel
-	lifecycle   lifecycle.Lifecycle
-	interaction interaction.Interaction
-	forwarder   forwarder.Forwarder
-	slug        slug.Slug
-	registry    Registry
-}
-
-func New(conn *ssh.ServerConn, initialReq <-chan *ssh.Request, sshChan <-chan ssh.NewChannel, sessionRegistry Registry, user string) Session {
-	slugManager := slug.New()
-	forwarderManager := forwarder.New(slugManager)
-	interactionManager := interaction.New(slugManager, forwarderManager)
-	lifecycleManager := lifecycle.New(conn, forwarderManager, slugManager, user)
-
-	interactionManager.SetLifecycle(lifecycleManager)
-	forwarderManager.SetLifecycle(lifecycleManager)
-	interactionManager.SetSessionRegistry(sessionRegistry)
-	lifecycleManager.SetSessionRegistry(sessionRegistry)
-
-	return &session{
-		initialReq:  initialReq,
-		sshChan:     sshChan,
-		lifecycle:   lifecycleManager,
-		interaction: interactionManager,
-		forwarder:   forwarderManager,
-		slug:        slugManager,
-		registry:    sessionRegistry,
-	}
-}
-
-func (s *session) Lifecycle() lifecycle.Lifecycle {
-	return s.lifecycle
-}
-
-func (s *session) Interaction() interaction.Interaction {
-	return s.interaction
-}
-
-func (s *session) Forwarder() forwarder.Forwarder {
-	return s.forwarder
-}
-
-func (s *session) Slug() slug.Slug {
-	return s.slug
-}
-
-func (s *session) Detail() *Detail {
-	var tunnelType string
-	if s.forwarder.TunnelType() == types.HTTP {
-		tunnelType = "HTTP"
-	} else if s.forwarder.TunnelType() == types.TCP {
-		tunnelType = "TCP"
-	} else {
-		tunnelType = "UNKNOWN"
-	}
-	return &Detail{
-		ForwardingType: tunnelType,
-		Slug:           s.slug.String(),
-		UserID:         s.lifecycle.User(),
+func (s *SSHSession) Detail() Detail {
+	return Detail{
+		ForwardingType: string(s.forwarder.GetTunnelType()),
+		Slug:           s.slugManager.Get(),
+		UserID:         s.lifecycle.GetUser(),
 		Active:         s.lifecycle.IsActive(),
 		StartedAt:      s.lifecycle.StartedAt(),
 	}
 }
 
-func (s *session) Start() error {
+func (s *SSHSession) Start() error {
 	var channel ssh.NewChannel
 	var ok bool
 	select {
-	case channel, ok = <-s.sshChan:
+	case channel, ok = <-s.sshReqChannel:
 		if !ok {
 			log.Println("Forwarding request channel closed")
 			return nil
@@ -136,7 +122,7 @@ func (s *session) Start() error {
 		return fmt.Errorf("no forwarding Request")
 	}
 
-	if (s.interaction.Mode() == types.HEADLESS && config.Getenv("MODE", "standalone") == "standalone") && s.lifecycle.User() == "UNAUTHORIZED" {
+	if (s.interaction.GetMode() == types.HEADLESS && config.Getenv("MODE", "standalone") == "standalone") || s.lifecycle.GetUser() == "UNAUTHORIZED" {
 		if err := tcpipReq.Reply(false, nil); err != nil {
 			log.Printf("cannot reply to tcpip req: %s\n", err)
 			return err
@@ -151,7 +137,7 @@ func (s *session) Start() error {
 	s.HandleTCPIPForward(tcpipReq)
 	s.interaction.Start()
 
-	s.lifecycle.Connection().Wait()
+	s.lifecycle.GetConnection().Wait()
 	if err := s.lifecycle.Close(); err != nil {
 		log.Printf("failed to close session: %v", err)
 		return err
@@ -159,7 +145,7 @@ func (s *session) Start() error {
 	return nil
 }
 
-func (s *session) waitForTCPIPForward() *ssh.Request {
+func (s *SSHSession) waitForTCPIPForward() *ssh.Request {
 	select {
 	case req, ok := <-s.initialReq:
 		if !ok {

session/slug/slug.go

@@ -1,24 +1,24 @@
 package slug
 
-type Slug interface {
-	String() string
+type Manager interface {
+	Get() string
 	Set(slug string)
 }
 
-type slug struct {
+type manager struct {
 	slug string
 }
 
-func New() Slug {
-	return &slug{
+func NewManager() Manager {
+	return &manager{
 		slug: "",
 	}
 }
 
-func (s *slug) String() string {
+func (s *manager) Get() string {
 	return s.slug
 }
 
-func (s *slug) Set(slug string) {
+func (s *manager) Set(slug string) {
 	s.slug = slug
 }

types/types.go

@@ -1,25 +1,26 @@
 package types
 
-type Status int
+type Status string
 
 const (
-	INITIALIZING Status = iota
-	RUNNING
+	INITIALIZING Status = "INITIALIZING"
+	RUNNING      Status = "RUNNING"
+	SETUP        Status = "SETUP"
 )
 
-type Mode int
+type Mode string
 
 const (
-	INTERACTIVE Mode = iota
-	HEADLESS
+	INTERACTIVE Mode = "INTERACTIVE"
+	HEADLESS    Mode = "HEADLESS"
 )
 
-type TunnelType int
+type TunnelType string
 
 const (
-	UNKNOWN TunnelType = iota
-	HTTP
-	TCP
+	UNKNOWN TunnelType = "UNKNOWN"
+	HTTP    TunnelType = "HTTP"
+	TCP     TunnelType = "TCP"
 )
 
 type SessionKey struct {