chore(port-forward): support multiple port forwarded

internal/portforward/interfaces.go

@@ -8,7 +8,7 @@ import (
 type Service interface {
 	Start(ctx context.Context) (runError <-chan error, err error)
 	Stop() (err error)
-	GetPortForwarded() (port uint16)
+	GetPortsForwarded() (ports []uint16)
 }
 
 type Routing interface {

internal/portforward/loop.go

@@ -150,11 +150,11 @@ func (l *Loop) Stop() (err error) {
 	return nil
 }
 
-func (l *Loop) GetPortForwarded() (port uint16) {
+func (l *Loop) GetPortsForwarded() (ports []uint16) {
 	if l.service == nil {
-		return 0
+		return nil
 	}
-	return l.service.GetPortForwarded()
+	return l.service.GetPortsForwarded()
 }
 
 func ptrTo[T any](value T) *T {

internal/portforward/service/fs.go

@@ -3,13 +3,20 @@ package service
 import (
 	"fmt"
 	"os"
+	"strings"
 )
 
-func (s *Service) writePortForwardedFile(port uint16) (err error) {
+func (s *Service) writePortForwardedFile(ports []uint16) (err error) {
+	portStrings := make([]string, len(ports))
+	for i, port := range ports {
+		portStrings[i] = fmt.Sprint(int(port))
+	}
+	fileData := []byte(strings.Join(portStrings, "\n"))
+
 	filepath := s.settings.Filepath
 	s.logger.Info("writing port file " + filepath)
 	const perms = os.FileMode(0644)
-	err = os.WriteFile(filepath, []byte(fmt.Sprint(port)), perms)
+	err = os.WriteFile(filepath, fileData, perms)
 	if err != nil {
 		return fmt.Errorf("writing file: %w", err)
 	}

internal/portforward/service/helpers.go

@@ -0,0 +1,22 @@
+package service
+
+import (
+	"fmt"
+	"strings"
+)
+
+func portsToString(ports []uint16) (s string) {
+	switch len(ports) {
+	case 0:
+		return "no port forwarded"
+	case 1:
+		return "port forwarded is " + fmt.Sprint(int(ports[0]))
+	default:
+		portStrings := make([]string, len(ports))
+		for i, port := range ports {
+			portStrings[i] = fmt.Sprint(int(port))
+		}
+		return "ports forwarded are " + strings.Join(portStrings[:len(portStrings)-1], ", ") +
+			" and " + portStrings[len(portStrings)-1]
+	}
+}

internal/portforward/service/helpers_test.go

@@ -0,0 +1,43 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_portsToString(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		ports []uint16
+		s     string
+	}{
+		"no_port": {
+			s: "no port forwarded",
+		},
+		"one_port": {
+			ports: []uint16{123},
+			s:     "port forwarded is 123",
+		},
+		"two_ports": {
+			ports: []uint16{123, 456},
+			s:     "ports forwarded are 123 and 456",
+		},
+		"three_ports": {
+			ports: []uint16{123, 456, 789},
+			s:     "ports forwarded are 123, 456 and 789",
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			s := portsToString(testCase.ports)
+
+			assert.Equal(t, testCase.s, s)
+		})
+	}
+}

internal/portforward/service/interfaces.go

@@ -28,6 +28,6 @@ type Logger interface {
 type PortForwarder interface {
 	Name() string
 	PortForward(ctx context.Context, objects utils.PortForwardObjects) (
-		port uint16, err error)
+		ports []uint16, err error)
 	KeepPortForward(ctx context.Context, objects utils.PortForwardObjects) (err error)
 }

internal/portforward/service/service.go

@@ -9,7 +9,7 @@ import (
 type Service struct {
 	// State
 	portMutex sync.RWMutex
-	port      uint16
+	ports     []uint16
 	// Fixed parameters
 	settings Settings
 	puid     int
@@ -40,8 +40,10 @@ func New(settings Settings, routing Routing, client *http.Client,
 	}
 }
 
-func (s *Service) GetPortForwarded() (port uint16) {
+func (s *Service) GetPortsForwarded() (ports []uint16) {
 	s.portMutex.RLock()
 	defer s.portMutex.RUnlock()
-	return s.port
+	ports = make([]uint16, len(s.ports))
+	copy(ports, s.ports)
+	return ports
 }

internal/portforward/service/start.go

@@ -31,13 +31,14 @@ func (s *Service) Start(ctx context.Context) (runError <-chan error, err error)
 		Username:       s.settings.Username,
 		Password:       s.settings.Password,
 	}
-	port, err := s.settings.PortForwarder.PortForward(ctx, obj)
+	ports, err := s.settings.PortForwarder.PortForward(ctx, obj)
 	if err != nil {
 		return nil, fmt.Errorf("port forwarding for the first time: %w", err)
 	}
 
-	s.logger.Info("port forwarded is " + fmt.Sprint(int(port)))
+	s.logger.Info(portsToString(ports))
 
+	for _, port := range ports {
 		err = s.portAllower.SetAllowedPort(ctx, port, s.settings.Interface)
 		if err != nil {
 			return nil, fmt.Errorf("allowing port in firewall: %w", err)
@@ -49,15 +50,16 @@ func (s *Service) Start(ctx context.Context) (runError <-chan error, err error)
 				return nil, fmt.Errorf("redirecting port in firewall: %w", err)
 			}
 		}
+	}
 
-	err = s.writePortForwardedFile(port)
+	err = s.writePortForwardedFile(ports)
 	if err != nil {
 		_ = s.cleanup()
 		return nil, fmt.Errorf("writing port file: %w", err)
 	}
 
 	s.portMutex.Lock()
-	s.port = port
+	s.ports = ports
 	s.portMutex.Unlock()
 
 	keepPortCtx, keepPortCancel := context.WithCancel(context.Background())

internal/portforward/service/stop.go

@@ -11,7 +11,7 @@ func (s *Service) Stop() (err error) {
 	defer s.startStopMutex.Unlock()
 
 	s.portMutex.RLock()
-	serviceNotRunning := s.port == 0
+	serviceNotRunning := len(s.ports) == 0
 	s.portMutex.RUnlock()
 	if serviceNotRunning {
 		// TODO replace with goservices.ErrAlreadyStopped
@@ -30,7 +30,8 @@ func (s *Service) cleanup() (err error) {
 	s.portMutex.Lock()
 	defer s.portMutex.Unlock()
 
-	err = s.portAllower.RemoveAllowedPort(context.Background(), s.port)
+	for _, port := range s.ports {
+		err = s.portAllower.RemoveAllowedPort(context.Background(), port)
 		if err != nil {
 			return fmt.Errorf("blocking previous port in firewall: %w", err)
 		}
@@ -38,13 +39,14 @@ func (s *Service) cleanup() (err error) {
 		if s.settings.ListeningPort != 0 {
 			ctx := context.Background()
 			const listeningPort = 0 // 0 to clear the redirection
-		err = s.portAllower.RedirectPort(ctx, s.settings.Interface, s.port, listeningPort)
+			err = s.portAllower.RedirectPort(ctx, s.settings.Interface, port, listeningPort)
 			if err != nil {
 				return fmt.Errorf("removing previous port redirection in firewall: %w", err)
 			}
 		}
+	}
 
-	s.port = 0
+	s.ports = nil
 
 	filepath := s.settings.Filepath
 	s.logger.Info("removing port file " + filepath)

internal/provider/privateinternetaccess/portforward.go

@@ -26,7 +26,7 @@ var (
 
 // PortForward obtains a VPN server side port forwarded from PIA.
 func (p *Provider) PortForward(ctx context.Context,
-	objects utils.PortForwardObjects) (port uint16, err error) {
+	objects utils.PortForwardObjects) (ports []uint16, err error) {
 	switch {
 	case objects.ServerName == "":
 		panic("server name cannot be empty")
@@ -43,17 +43,17 @@ func (p *Provider) PortForward(ctx context.Context,
 	logger := objects.Logger
 
 	if !objects.CanPortForward {
-		return 0, fmt.Errorf("%w: for server %s", ErrServerNameNotFound, serverName)
+		return nil, fmt.Errorf("%w: for server %s", ErrServerNameNotFound, serverName)
 	}
 
 	privateIPClient, err := newHTTPClient(serverName)
 	if err != nil {
-		return 0, fmt.Errorf("creating custom HTTP client: %w", err)
+		return nil, fmt.Errorf("creating custom HTTP client: %w", err)
 	}
 
 	data, err := readPIAPortForwardData(p.portForwardPath)
 	if err != nil {
-		return 0, fmt.Errorf("reading saved port forwarded data: %w", err)
+		return nil, fmt.Errorf("reading saved port forwarded data: %w", err)
 	}
 
 	dataFound := data.Port > 0
@@ -73,7 +73,7 @@ func (p *Provider) PortForward(ctx context.Context,
 		data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, objects.Gateway,
 			p.portForwardPath, objects.Username, objects.Password)
 		if err != nil {
-			return 0, fmt.Errorf("refreshing port forward data: %w", err)
+			return nil, fmt.Errorf("refreshing port forward data: %w", err)
 		}
 		durationToExpiration = data.Expiration.Sub(p.timeNow())
 	}
@@ -81,10 +81,10 @@ func (p *Provider) PortForward(ctx context.Context,
 
 	// First time binding
 	if err := bindPort(ctx, privateIPClient, objects.Gateway, data); err != nil {
-		return 0, fmt.Errorf("binding port: %w", err)
+		return nil, fmt.Errorf("binding port: %w", err)
 	}
 
-	return data.Port, nil
+	return []uint16{data.Port}, nil
 }
 
 var (

internal/provider/protonvpn/portforward.go

@@ -13,7 +13,7 @@ import (
 
 // PortForward obtains a VPN server side port forwarded from ProtonVPN gateway.
 func (p *Provider) PortForward(ctx context.Context, objects utils.PortForwardObjects) (
-	port uint16, err error) {
+	ports []uint16, err error) {
 	client := natpmp.New()
 	_, externalIPv4Address, err := client.ExternalAddress(ctx,
 		objects.Gateway)
@@ -21,7 +21,7 @@ func (p *Provider) PortForward(ctx context.Context, objects utils.PortForwardObj
 		if strings.HasSuffix(err.Error(), "connection refused") {
 			err = fmt.Errorf("%w - make sure you have +pmp at the end of your OpenVPN username", err)
 		}
-		return 0, fmt.Errorf("getting external IPv4 address: %w", err)
+		return nil, fmt.Errorf("getting external IPv4 address: %w", err)
 	}
 
 	logger := objects.Logger
@@ -34,7 +34,7 @@ func (p *Provider) PortForward(ctx context.Context, objects utils.PortForwardObj
 		client.AddPortMapping(ctx, objects.Gateway, "udp",
 			internalPort, externalPort, lifetime)
 	if err != nil {
-		return 0, fmt.Errorf("adding UDP port mapping: %w", err)
+		return nil, fmt.Errorf("adding UDP port mapping: %w", err)
 	}
 	checkLifetime(logger, "UDP", lifetime, assignedLifetime)
 
@@ -42,16 +42,15 @@ func (p *Provider) PortForward(ctx context.Context, objects utils.PortForwardObj
 		client.AddPortMapping(ctx, objects.Gateway, "tcp",
 			internalPort, externalPort, lifetime)
 	if err != nil {
-		return 0, fmt.Errorf("adding TCP port mapping: %w", err)
+		return nil, fmt.Errorf("adding TCP port mapping: %w", err)
 	}
 	checkLifetime(logger, "TCP", lifetime, assignedLifetime)
 
 	checkExternalPorts(logger, assignedUDPExternalPort, assignedTCPExternalPort)
-	port = assignedTCPExternalPort
 
-	p.portForwarded = port
+	p.portForwarded = assignedTCPExternalPort
 
-	return port, nil
+	return []uint16{assignedTCPExternalPort}, nil
 }
 
 func checkLifetime(logger utils.Logger, protocol string,

internal/server/interfaces.go

@@ -22,7 +22,7 @@ type DNSLoop interface {
 }
 
 type PortForwardedGetter interface {
-	GetPortForwarded() (portForwarded uint16)
+	GetPortsForwarded() (ports []uint16)
 }
 
 type PublicIPLoop interface {

internal/server/openvpn.go

@@ -123,12 +123,21 @@ func (h *openvpnHandler) getSettings(w http.ResponseWriter) {
 }
 
 func (h *openvpnHandler) getPortForwarded(w http.ResponseWriter) {
-	port := h.pf.GetPortForwarded()
+	ports := h.pf.GetPortsForwarded()
 	encoder := json.NewEncoder(w)
-	data := portWrapper{Port: port}
-	if err := encoder.Encode(data); err != nil {
+	var data any
+	switch len(ports) {
+	case 0:
+		data = portWrapper{Port: 0} // TODO v4 change to portsWrapper
+	case 1:
+		data = portWrapper{Port: ports[0]} // TODO v4 change to portsWrapper
+	default:
+		data = portsWrapper{Ports: ports}
+	}
+
+	err := encoder.Encode(data)
+	if err != nil {
 		h.warner.Warn(err.Error())
 		w.WriteHeader(http.StatusInternalServerError)
-		return
 	}
 }

internal/server/wrappers.go

@@ -25,10 +25,14 @@ func (sw *statusWrapper) getStatus() (status models.LoopStatus, err error) {
 	}
 }
 
-type portWrapper struct {
+type portWrapper struct { // TODO v4 remove
 	Port uint16 `json:"port"`
 }
 
+type portsWrapper struct {
+	Ports []uint16 `json:"ports"`
+}
+
 type outcomeWrapper struct {
 	Outcome string `json:"outcome"`
 }

internal/vpn/interfaces.go

@@ -47,7 +47,7 @@ type Provider interface {
 type PortForwarder interface {
 	Name() string
 	PortForward(ctx context.Context, objects utils.PortForwardObjects) (
-		port uint16, err error)
+		ports []uint16, err error)
 	KeepPortForward(ctx context.Context, objects utils.PortForwardObjects) (err error)
 }
 

internal/vpn/portforward.go

@@ -61,8 +61,8 @@ func (n *noPortForwarder) Name() string {
 }
 
 func (n *noPortForwarder) PortForward(context.Context, pfutils.PortForwardObjects) (
-	port uint16, err error) {
-	return 0, fmt.Errorf("%w: for %s", ErrPortForwardingNotSupported, n.providerName)
+	ports []uint16, err error) {
+	return nil, fmt.Errorf("%w: for %s", ErrPortForwardingNotSupported, n.providerName)
 }
 
 func (n *noPortForwarder) KeepPortForward(context.Context, pfutils.PortForwardObjects) (err error) {