Maint: port forwarding refactoring (#543)

- portforward package
- portforward run loop
- Less functional arguments and cycles

cmd/gluetun/main.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"net"
 	"net/http"
 	"os"
 	"os/signal"
@@ -24,6 +23,7 @@ import (
 	"github.com/qdm12/gluetun/internal/httpproxy"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/openvpn"
+	"github.com/qdm12/gluetun/internal/portforward"
 	"github.com/qdm12/gluetun/internal/publicip"
 	"github.com/qdm12/gluetun/internal/routing"
 	"github.com/qdm12/gluetun/internal/server"
@@ -321,8 +321,16 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	tickersGroupHandler := goshutdown.NewGroupHandler("tickers", defaultGroupSettings)
 	otherGroupHandler := goshutdown.NewGroupHandler("other", defaultGroupSettings)
 
+	portForwardLogger := logger.NewChild(logging.Settings{Prefix: "port forwarding: "})
+	portForwardLooper := portforward.NewLoop(allSettings.OpenVPN.Provider.PortForwarding,
+		httpClient, firewallConf, portForwardLogger)
+	portForwardHandler, portForwardCtx, portForwardDone := goshutdown.NewGoRoutineHandler(
+		"port forwarding", goshutdown.GoRoutineSettings{Timeout: time.Second})
+	go portForwardLooper.Run(portForwardCtx, portForwardDone)
+
+	openvpnLogger := logger.NewChild(logging.Settings{Prefix: "openvpn: "})
 	openvpnLooper := openvpn.NewLoop(allSettings.OpenVPN, nonRootUsername, puid, pgid, allServers,
-		ovpnConf, firewallConf, logger, httpClient, tunnelReadyCh)
+		ovpnConf, firewallConf, routingConf, portForwardLooper, openvpnLogger, httpClient, tunnelReadyCh)
 	openvpnHandler, openvpnCtx, openvpnDone := goshutdown.NewGoRoutineHandler(
 		"openvpn", goshutdown.GoRoutineSettings{Timeout: time.Second})
 	// wait for restartOpenvpn
@@ -378,8 +386,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		"events routing", defaultGoRoutineSettings)
 	go routeReadyEvents(eventsRoutingCtx, eventsRoutingDone, buildInfo, tunnelReadyCh,
 		unboundLooper, updaterLooper, publicIPLooper, routingConf, logger, httpClient,
-		allSettings.VersionInformation, allSettings.OpenVPN.Provider.PortForwarding.Enabled, openvpnLooper.PortForward,
-	)
+		allSettings.VersionInformation)
 	controlGroupHandler.Add(eventsRoutingHandler)
 
 	controlServerAddress := ":" + strconv.Itoa(int(allSettings.ControlServer.Port))
@@ -406,7 +413,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	}
 	orderHandler := goshutdown.NewOrder("gluetun", orderSettings)
 	orderHandler.Append(controlGroupHandler, tickersGroupHandler, healthServerHandler,
-		openvpnHandler, otherGroupHandler)
+		openvpnHandler, portForwardHandler, otherGroupHandler)
 
 	// Start openvpn for the first time in a blocking call
 	// until openvpn is launched
@@ -414,13 +421,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	<-ctx.Done()
 
-	if allSettings.OpenVPN.Provider.PortForwarding.Enabled {
-		logger.Info("Clearing forwarded port status file " + allSettings.OpenVPN.Provider.PortForwarding.Filepath)
-		if err := os.Remove(allSettings.OpenVPN.Provider.PortForwarding.Filepath); err != nil {
-			logger.Error(err.Error())
-		}
-	}
-
 	return orderHandler.Shutdown(context.Background())
 }
 
@@ -450,7 +450,7 @@ func routeReadyEvents(ctx context.Context, done chan<- struct{}, buildInfo model
 	tunnelReadyCh <-chan struct{},
 	unboundLooper dns.Looper, updaterLooper updater.Looper, publicIPLooper publicip.Looper,
 	routing routing.VPNGetter, logger logging.Logger, httpClient *http.Client,
-	versionInformation, portForwardingEnabled bool, startPortForward func(vpnGateway net.IP)) {
+	versionInformation bool) {
 	defer close(done)
 
 	// for linters only
@@ -503,15 +503,6 @@ func routeReadyEvents(ctx context.Context, done chan<- struct{}, buildInfo model
 			updaterTickerDone = make(chan struct{})
 			go unboundLooper.RunRestartTicker(restartTickerContext, unboundTickerDone)
 			go updaterLooper.RunRestartTicker(restartTickerContext, updaterTickerDone)
-			if portForwardingEnabled {
-				// vpnGateway required only for PIA
-				vpnGateway, err := routing.VPNLocalGatewayIP()
-				if err != nil {
-					logger.Error("cannot get VPN local gateway IP: " + err.Error())
-				}
-				logger.Info("VPN gateway IP address: " + vpnGateway.String())
-				startPortForward(vpnGateway)
-			}
 		}
 	}
 }

internal/openvpn/logs.go

@@ -42,6 +42,7 @@ func (l *Loop) collectLines(stdout, stderr <-chan string, done chan<- struct{})
 		}
 		if strings.Contains(line, "Initialization Sequence Completed") {
 			l.tunnelReady <- struct{}{}
+			l.startPFCh <- struct{}{}
 		}
 	}
 }

internal/openvpn/loop.go

@@ -1,7 +1,6 @@
 package openvpn
 
 import (
-	"net"
 	"net/http"
 	"time"
 
@@ -11,6 +10,8 @@ import (
 	"github.com/qdm12/gluetun/internal/loopstate"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/openvpn/state"
+	"github.com/qdm12/gluetun/internal/portforward"
+	"github.com/qdm12/gluetun/internal/routing"
 	"github.com/qdm12/golibs/logging"
 )
 
@@ -22,8 +23,6 @@ type Looper interface {
 	loopstate.Applier
 	SettingsGetSetter
 	ServersGetterSetter
-	PortForwadedGetter
-	PortForwader
 }
 
 type Loop struct {
@@ -35,19 +34,21 @@ type Loop struct {
 	pgid           int
 	targetConfPath string
 	// Configurators
-	conf StarterAuthWriter
-	fw   firewallConfigurer
+	conf        StarterAuthWriter
+	fw          firewallConfigurer
+	routing     routing.VPNLocalGatewayIPGetter
+	portForward portforward.StartStopper
 	// Other objects
-	logger, pfLogger logging.Logger
-	client           *http.Client
-	tunnelReady      chan<- struct{}
+	logger      logging.Logger
+	client      *http.Client
+	tunnelReady chan<- struct{}
 	// Internal channels and values
-	stop               <-chan struct{}
-	stopped            chan<- struct{}
-	start              <-chan struct{}
-	running            chan<- models.LoopStatus
-	portForwardSignals chan net.IP
-	userTrigger        bool
+	stop        <-chan struct{}
+	stopped     chan<- struct{}
+	start       <-chan struct{}
+	running     chan<- models.LoopStatus
+	userTrigger bool
+	startPFCh   chan struct{}
 	// Internal constant values
 	backoffTime time.Duration
 }
@@ -63,7 +64,8 @@ const (
 
 func NewLoop(settings configuration.OpenVPN, username string,
 	puid, pgid int, allServers models.AllServers, conf Configurator,
-	fw firewallConfigurer, logger logging.ParentLogger,
+	fw firewallConfigurer, routing routing.VPNLocalGatewayIPGetter,
+	portForward portforward.StartStopper, logger logging.Logger,
 	client *http.Client, tunnelReady chan<- struct{}) *Loop {
 	start := make(chan struct{})
 	running := make(chan models.LoopStatus)
@@ -74,24 +76,25 @@ func NewLoop(settings configuration.OpenVPN, username string,
 	state := state.New(statusManager, settings, allServers)
 
 	return &Loop{
-		statusManager:      statusManager,
-		state:              state,
-		username:           username,
-		puid:               puid,
-		pgid:               pgid,
-		targetConfPath:     constants.OpenVPNConf,
-		conf:               conf,
-		fw:                 fw,
-		logger:             logger.NewChild(logging.Settings{Prefix: "openvpn: "}),
-		pfLogger:           logger.NewChild(logging.Settings{Prefix: "port forwarding: "}),
-		client:             client,
-		tunnelReady:        tunnelReady,
-		start:              start,
-		running:            running,
-		stop:               stop,
-		stopped:            stopped,
-		portForwardSignals: make(chan net.IP),
-		userTrigger:        true,
-		backoffTime:        defaultBackoffTime,
+		statusManager:  statusManager,
+		state:          state,
+		username:       username,
+		puid:           puid,
+		pgid:           pgid,
+		targetConfPath: constants.OpenVPNConf,
+		conf:           conf,
+		fw:             fw,
+		routing:        routing,
+		portForward:    portForward,
+		logger:         logger,
+		client:         client,
+		tunnelReady:    tunnelReady,
+		start:          start,
+		running:        running,
+		stop:           stop,
+		stopped:        stopped,
+		userTrigger:    true,
+		startPFCh:      make(chan struct{}),
+		backoffTime:    defaultBackoffTime,
 	}
 }

internal/openvpn/portforward.go

@@ -0,0 +1,47 @@
+package openvpn
+
+import (
+	"context"
+	"time"
+
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/portforward"
+	"github.com/qdm12/gluetun/internal/provider"
+)
+
+func (l *Loop) startPortForwarding(ctx context.Context,
+	portForwarder provider.PortForwarder, serverName string) {
+	if !l.GetSettings().Provider.PortForwarding.Enabled {
+		return
+	}
+	// only used for PIA for now
+	gateway, err := l.routing.VPNLocalGatewayIP()
+	if err != nil {
+		l.logger.Error("cannot obtain VPN local gateway IP: " + err.Error())
+		return
+	}
+	l.logger.Info("VPN gateway IP address: " + gateway.String())
+	pfData := portforward.StartData{
+		PortForwarder: portForwarder,
+		Gateway:       gateway,
+		ServerName:    serverName,
+		Interface:     constants.TUN,
+	}
+	_, err = l.portForward.Start(ctx, pfData)
+	if err != nil {
+		l.logger.Error("cannot start port forwarding: " + err.Error())
+	}
+}
+
+func (l *Loop) stopPortForwarding(ctx context.Context, timeout time.Duration) {
+	if timeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+		defer cancel()
+	}
+
+	_, err := l.portForward.Stop(ctx)
+	if err != nil {
+		l.logger.Error("cannot stop port forwarding: " + err.Error())
+	}
+}

internal/openvpn/portforwarded.go

@@ -1,39 +0,0 @@
-package openvpn
-
-import (
-	"context"
-	"net"
-	"net/http"
-
-	"github.com/qdm12/gluetun/internal/openvpn/state"
-	"github.com/qdm12/gluetun/internal/provider"
-)
-
-type PortForwadedGetter = state.PortForwardedGetter
-
-func (l *Loop) GetPortForwarded() (port uint16) {
-	return l.state.GetPortForwarded()
-}
-
-type PortForwader interface {
-	PortForward(vpnGatewayIP net.IP)
-}
-
-func (l *Loop) PortForward(vpnGateway net.IP) { l.portForwardSignals <- vpnGateway }
-
-// portForward is a blocking operation which may or may not be infinite.
-// You should therefore always call it in a goroutine.
-func (l *Loop) portForward(ctx context.Context,
-	providerConf provider.Provider, client *http.Client, gateway net.IP) {
-	settings := l.state.GetSettings()
-	if !settings.Provider.PortForwarding.Enabled {
-		return
-	}
-	syncState := func(port uint16) (pfFilepath string) {
-		l.state.SetPortForwarded(port)
-		settings := l.state.GetSettings()
-		return settings.Provider.PortForwarding.Filepath
-	}
-	providerConf.PortForward(ctx, client, l.pfLogger,
-		gateway, l.fw, syncState)
-}

internal/openvpn/run.go

@@ -88,41 +88,31 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			<-lineCollectionDone
 		}
 
-		// Needs the stream line from main.go to know when the tunnel is up
-		portForwardDone := make(chan struct{})
-		go func(ctx context.Context) {
-			defer close(portForwardDone)
-			select {
-			// TODO have a way to disable pf with a context
-			case <-ctx.Done():
-				return
-			case gateway := <-l.portForwardSignals:
-				l.portForward(ctx, providerConf, l.client, gateway)
-			}
-		}(openvpnCtx)
-
 		l.backoffTime = defaultBackoffTime
 		l.signalOrSetStatus(constants.Running)
 
 		stayHere := true
 		for stayHere {
 			select {
+			case <-l.startPFCh:
+				l.startPortForwarding(ctx, providerConf, connection.Hostname)
 			case <-ctx.Done():
+				const pfTimeout = 100 * time.Millisecond
+				l.stopPortForwarding(context.Background(), pfTimeout)
 				openvpnCancel()
 				<-waitError
 				close(waitError)
 				closeStreams()
-				<-portForwardDone
 				return
 			case <-l.stop:
 				l.userTrigger = true
 				l.logger.Info("stopping")
+				l.stopPortForwarding(ctx, 0)
 				openvpnCancel()
 				<-waitError
 				// do not close waitError or the waitError
 				// select case will trigger
 				closeStreams()
-				<-portForwardDone
 				l.stopped <- struct{}{}
 			case <-l.start:
 				l.userTrigger = true
@@ -134,9 +124,9 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 
 				l.statusManager.Lock() // prevent SetStatus from running in parallel
 
+				l.stopPortForwarding(ctx, 0)
 				openvpnCancel()
 				l.statusManager.SetStatus(constants.Crashed)
-				<-portForwardDone
 				l.logAndWait(ctx, err)
 				stayHere = false
 

internal/openvpn/state/state.go

@@ -13,7 +13,6 @@ var _ Manager = (*State)(nil)
 type Manager interface {
 	SettingsGetSetter
 	ServersGetterSetter
-	PortForwardedGetterSetter
 	GetSettingsAndServers() (settings configuration.OpenVPN,
 		allServers models.AllServers)
 }
@@ -36,9 +35,6 @@ type State struct {
 
 	allServers   models.AllServers
 	allServersMu sync.RWMutex
-
-	portForwarded   uint16
-	portForwardedMu sync.RWMutex
 }
 
 func (s *State) GetSettingsAndServers() (settings configuration.OpenVPN,

internal/portforward/firewall.go

@@ -0,0 +1,32 @@
+package portforward
+
+import "context"
+
+// firewallBlockPort obtains the state port thread safely and blocks
+// it in the firewall if it is not the zero value (0).
+func (l *Loop) firewallBlockPort(ctx context.Context) {
+	port := l.state.GetPortForwarded()
+	if port == 0 {
+		return
+	}
+
+	err := l.portAllower.RemoveAllowedPort(ctx, port)
+	if err != nil {
+		l.logger.Error("cannot block previous port in firewall: " + err.Error())
+	}
+}
+
+// firewallAllowPort obtains the state port thread safely and allows
+// it in the firewall if it is not the zero value (0).
+func (l *Loop) firewallAllowPort(ctx context.Context) {
+	port := l.state.GetPortForwarded()
+	if port == 0 {
+		return
+	}
+
+	startData := l.state.GetStartData()
+	err := l.portAllower.SetAllowedPort(ctx, port, startData.Interface)
+	if err != nil {
+		l.logger.Error("cannot allow port through firewall: " + err.Error())
+	}
+}

internal/portforward/fs.go

@@ -0,0 +1,37 @@
+package portforward
+
+import (
+	"fmt"
+	"os"
+)
+
+func (l *Loop) removePortForwardedFile() {
+	filepath := l.state.GetSettings().Filepath
+	l.logger.Info("removing port file " + filepath)
+	if err := os.Remove(filepath); err != nil {
+		l.logger.Error(err.Error())
+	}
+}
+
+func (l *Loop) writePortForwardedFile(port uint16) {
+	filepath := l.state.GetSettings().Filepath
+	l.logger.Info("writing port file " + filepath)
+	if err := writePortForwardedToFile(filepath, port); err != nil {
+		l.logger.Error(err.Error())
+	}
+}
+
+func writePortForwardedToFile(filepath string, port uint16) (err error) {
+	file, err := os.OpenFile(filepath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+	if err != nil {
+		return err
+	}
+
+	_, err = file.Write([]byte(fmt.Sprint(port)))
+	if err != nil {
+		_ = file.Close()
+		return err
+	}
+
+	return file.Close()
+}

internal/portforward/get.go

@@ -0,0 +1,9 @@
+package portforward
+
+import "github.com/qdm12/gluetun/internal/portforward/state"
+
+type Getter = state.PortForwardedGetter
+
+func (l *Loop) GetPortForwarded() (port uint16) {
+	return l.state.GetPortForwarded()
+}

internal/portforward/helpers.go

@@ -0,0 +1,22 @@
+package portforward
+
+import (
+	"context"
+	"time"
+)
+
+func (l *Loop) logAndWait(ctx context.Context, err error) {
+	if err != nil {
+		l.logger.Error(err.Error())
+	}
+	l.logger.Info("retrying in " + l.backoffTime.String())
+	timer := time.NewTimer(l.backoffTime)
+	l.backoffTime *= 2
+	select {
+	case <-timer.C:
+	case <-ctx.Done():
+		if !timer.Stop() {
+			<-timer.C
+		}
+	}
+}

internal/portforward/loop.go

@@ -0,0 +1,71 @@
+package portforward
+
+import (
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/firewall"
+	"github.com/qdm12/gluetun/internal/loopstate"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/portforward/state"
+	"github.com/qdm12/golibs/logging"
+)
+
+var _ Looper = (*Loop)(nil)
+
+type Looper interface {
+	Runner
+	loopstate.Getter
+	StartStopper
+	SettingsGetSetter
+	Getter
+}
+
+type Loop struct {
+	statusManager loopstate.Manager
+	state         state.Manager
+	// Objects
+	client      *http.Client
+	portAllower firewall.PortAllower
+	logger      logging.Logger
+	// Internal channels and locks
+	start       chan struct{}
+	running     chan models.LoopStatus
+	stop        chan struct{}
+	stopped     chan struct{}
+	startMu     sync.Mutex
+	backoffTime time.Duration
+	userTrigger bool
+}
+
+const defaultBackoffTime = 5 * time.Second
+
+func NewLoop(settings configuration.PortForwarding,
+	client *http.Client, portAllower firewall.PortAllower,
+	logger logging.Logger) *Loop {
+	start := make(chan struct{})
+	running := make(chan models.LoopStatus)
+	stop := make(chan struct{})
+	stopped := make(chan struct{})
+
+	statusManager := loopstate.New(constants.Stopped, start, running, stop, stopped)
+	state := state.New(statusManager, settings)
+
+	return &Loop{
+		statusManager: statusManager,
+		state:         state,
+		// Objects
+		client:      client,
+		portAllower: portAllower,
+		logger:      logger,
+		start:       start,
+		running:     running,
+		stop:        stop,
+		stopped:     stopped,
+		userTrigger: true,
+		backoffTime: defaultBackoffTime,
+	}
+}

internal/portforward/run.go

@@ -0,0 +1,97 @@
+package portforward
+
+import (
+	"context"
+	"strconv"
+
+	"github.com/qdm12/gluetun/internal/constants"
+)
+
+type Runner interface {
+	Run(ctx context.Context, done chan<- struct{})
+}
+
+func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
+	defer close(done)
+
+	select {
+	case <-l.start: // l.state.SetStartData called beforehand
+	case <-ctx.Done():
+		return
+	}
+
+	for ctx.Err() == nil {
+		pfCtx, pfCancel := context.WithCancel(ctx)
+
+		portCh := make(chan uint16)
+		errorCh := make(chan error)
+
+		startData := l.state.GetStartData()
+
+		go func(ctx context.Context, startData StartData) {
+			port, err := startData.PortForwarder.PortForward(ctx, l.client, l.logger,
+				startData.Gateway, startData.ServerName)
+			if err != nil {
+				errorCh <- err
+				return
+			}
+			portCh <- port
+
+			// Infinite loop
+			err = startData.PortForwarder.KeepPortForward(ctx, l.client, l.logger,
+				port, startData.Gateway, startData.ServerName)
+			errorCh <- err
+		}(pfCtx, startData)
+
+		if l.userTrigger {
+			l.userTrigger = false
+			l.running <- constants.Running
+		} else { // crash
+			l.backoffTime = defaultBackoffTime
+			l.statusManager.SetStatus(constants.Running)
+		}
+
+		stayHere := true
+		for stayHere {
+			select {
+			case <-ctx.Done():
+				pfCancel()
+				<-errorCh
+				close(errorCh)
+				close(portCh)
+				l.removePortForwardedFile()
+				l.firewallBlockPort(ctx)
+				l.state.SetPortForwarded(0)
+				return
+			case <-l.start:
+				l.userTrigger = true
+				l.logger.Info("starting")
+				pfCancel()
+				stayHere = false
+			case <-l.stop:
+				l.userTrigger = true
+				l.logger.Info("stopping")
+				pfCancel()
+				<-errorCh
+				l.removePortForwardedFile()
+				l.firewallBlockPort(ctx)
+				l.state.SetPortForwarded(0)
+				l.stopped <- struct{}{}
+			case port := <-portCh:
+				l.logger.Info("port forwarded is " + strconv.Itoa(int(port)))
+				l.firewallBlockPort(ctx)
+				l.state.SetPortForwarded(port)
+				l.firewallAllowPort(ctx)
+				l.writePortForwardedFile(port)
+			case err := <-errorCh:
+				pfCancel()
+				close(errorCh)
+				close(portCh)
+				l.statusManager.SetStatus(constants.Crashed)
+				l.logAndWait(ctx, err)
+				stayHere = false
+			}
+		}
+		pfCancel() // for linting
+	}
+}

internal/portforward/settings.go

@@ -0,0 +1,19 @@
+package portforward
+
+import (
+	"context"
+
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/portforward/state"
+)
+
+type SettingsGetSetter = state.SettingsGetSetter
+
+func (l *Loop) GetSettings() (settings configuration.PortForwarding) {
+	return l.state.GetSettings()
+}
+
+func (l *Loop) SetSettings(ctx context.Context, settings configuration.PortForwarding) (
+	outcome string) {
+	return l.state.SetSettings(ctx, settings)
+}

internal/portforward/state/settings.go

@@ -0,0 +1,55 @@
+package state
+
+import (
+	"context"
+	"os"
+	"reflect"
+
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/constants"
+)
+
+type SettingsGetSetter interface {
+	GetSettings() (settings configuration.PortForwarding)
+	SetSettings(ctx context.Context,
+		settings configuration.PortForwarding) (outcome string)
+}
+
+func (s *State) GetSettings() (settings configuration.PortForwarding) {
+	s.settingsMu.RLock()
+	defer s.settingsMu.RUnlock()
+	return s.settings
+}
+
+func (s *State) SetSettings(ctx context.Context, settings configuration.PortForwarding) (
+	outcome string) {
+	s.settingsMu.Lock()
+
+	settingsUnchanged := reflect.DeepEqual(s.settings, settings)
+	if settingsUnchanged {
+		s.settingsMu.Unlock()
+		return "settings left unchanged"
+	}
+
+	if s.settings.Filepath != settings.Filepath {
+		_ = os.Rename(s.settings.Filepath, settings.Filepath)
+	}
+
+	newEnabled := settings.Enabled
+	previousEnabled := s.settings.Enabled
+
+	s.settings = settings
+	s.settingsMu.Unlock()
+
+	switch {
+	case !newEnabled && !previousEnabled:
+	case newEnabled && previousEnabled:
+		// no need to restart for now since we os.Rename the file here.
+	case newEnabled && !previousEnabled:
+		_, _ = s.statusApplier.ApplyStatus(ctx, constants.Running)
+	case !newEnabled && previousEnabled:
+		_, _ = s.statusApplier.ApplyStatus(ctx, constants.Stopped)
+	}
+
+	return "settings updated"
+}

internal/portforward/state/startdata.go

@@ -0,0 +1,39 @@
+package state
+
+import (
+	"net"
+
+	"github.com/qdm12/gluetun/internal/provider"
+)
+
+type StartData struct {
+	PortForwarder provider.PortForwarder
+	Gateway       net.IP // needed for PIA
+	ServerName    string // needed for PIA
+	Interface     string // tun0 or wg0 for example
+}
+
+type StartDataGetterSetter interface {
+	StartDataGetter
+	StartDataSetter
+}
+
+type StartDataGetter interface {
+	GetStartData() (startData StartData)
+}
+
+func (s *State) GetStartData() (startData StartData) {
+	s.startDataMu.RLock()
+	defer s.startDataMu.RUnlock()
+	return s.startData
+}
+
+type StartDataSetter interface {
+	SetStartData(startData StartData)
+}
+
+func (s *State) SetStartData(startData StartData) {
+	s.startDataMu.Lock()
+	defer s.startDataMu.Unlock()
+	s.startData = startData
+}

internal/portforward/state/state.go

@@ -0,0 +1,37 @@
+package state
+
+import (
+	"sync"
+
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/loopstate"
+)
+
+var _ Manager = (*State)(nil)
+
+type Manager interface {
+	SettingsGetSetter
+	PortForwardedGetterSetter
+	StartDataGetterSetter
+}
+
+func New(statusApplier loopstate.Applier,
+	settings configuration.PortForwarding) *State {
+	return &State{
+		statusApplier: statusApplier,
+		settings:      settings,
+	}
+}
+
+type State struct {
+	statusApplier loopstate.Applier
+
+	settings   configuration.PortForwarding
+	settingsMu sync.RWMutex
+
+	portForwarded   uint16
+	portForwardedMu sync.RWMutex
+
+	startData   StartData
+	startDataMu sync.RWMutex
+}

internal/portforward/status.go

@@ -0,0 +1,33 @@
+package portforward
+
+import (
+	"context"
+
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/portforward/state"
+)
+
+func (l *Loop) GetStatus() (status models.LoopStatus) {
+	return l.statusManager.GetStatus()
+}
+
+type StartData = state.StartData
+
+type StartStopper interface {
+	Start(ctx context.Context, data StartData) (
+		outcome string, err error)
+	Stop(ctx context.Context) (outcome string, err error)
+}
+
+func (l *Loop) Start(ctx context.Context, data StartData) (
+	outcome string, err error) {
+	l.startMu.Lock()
+	defer l.startMu.Unlock()
+	l.state.SetStartData(data)
+	return l.statusManager.ApplyStatus(ctx, constants.Running)
+}
+
+func (l *Loop) Stop(ctx context.Context) (outcome string, err error) {
+	return l.statusManager.ApplyStatus(ctx, constants.Stopped)
+}

internal/provider/privateinternetaccess/connection.go

@@ -31,6 +31,7 @@ func (p *PIA) GetOpenVPNConnection(selection configuration.ServerSelection) (
 				IP:       IP,
 				Port:     port,
 				Protocol: protocol,
+				Hostname: server.ServerName, // used for port forwarding TLS
 			}
 			connections = append(connections, connection)
 		}

internal/provider/privateinternetaccess/portforward.go

@@ -15,48 +15,51 @@ import (
 	"strings"
 	"time"
 
-	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/format"
 	"github.com/qdm12/golibs/logging"
 )
 
 var (
-	ErrBindPort = errors.New("cannot bind port")
+	ErrGatewayIPIsNil           = errors.New("gateway IP address is nil")
+	ErrServerNameEmpty          = errors.New("server name is empty")
+	ErrCreateHTTPClient         = errors.New("cannot create custom HTTP client")
+	ErrReadSavedPortForwardData = errors.New("cannot read saved port forwarded data")
+	ErrRefreshPortForwardData   = errors.New("cannot refresh port forward data")
+	ErrBindPort                 = errors.New("cannot bind port")
 )
 
 // PortForward obtains a VPN server side port forwarded from PIA.
-//nolint:gocognit
 func (p *PIA) PortForward(ctx context.Context, client *http.Client,
-	logger logging.Logger, gateway net.IP, portAllower firewall.PortAllower,
-	syncState func(port uint16) (pfFilepath string)) {
-	commonName := p.activeServer.ServerName
-	if !p.activeServer.PortForward {
-		logger.Error("The server " + commonName +
-			" (region " + p.activeServer.Region + ") does not support port forwarding")
-		return
-	}
+	logger logging.Logger, gateway net.IP, serverName string) (
+	port uint16, err error) {
+	// commonName := p.activeServer.ServerName
+	// if !p.activeServer.PortForward {
+	// 	logger.Error("The server " + commonName +
+	// 		" (region " + p.activeServer.Region + ") does not support port forwarding")
+	// 	return
+	// }
 	if gateway == nil {
-		logger.Error("aborting because: VPN gateway IP address was not found")
-		return
+		return 0, ErrGatewayIPIsNil
+	} else if serverName == "" {
+		return 0, ErrServerNameEmpty
 	}
 
-	privateIPClient, err := newHTTPClient(commonName)
+	privateIPClient, err := newHTTPClient(serverName)
 	if err != nil {
-		logger.Error("aborting because: " + err.Error())
-		return
+		return 0, fmt.Errorf("%w: %s", ErrCreateHTTPClient, err)
 	}
 
 	data, err := readPIAPortForwardData(p.portForwardPath)
 	if err != nil {
-		logger.Error(err.Error())
+		return 0, fmt.Errorf("%w: %s", ErrReadSavedPortForwardData, err)
 	}
+
 	dataFound := data.Port > 0
 	durationToExpiration := data.Expiration.Sub(p.timeNow())
 	expired := durationToExpiration <= 0
 
 	if dataFound {
-		logger.Info("Found persistent forwarded port data for port " + strconv.Itoa(int(data.Port)))
+		logger.Info("Found saved forwarded port data for port " + strconv.Itoa(int(data.Port)))
 		if expired {
 			logger.Warn("Forwarded port data expired on " +
 				data.Expiration.Format(time.RFC1123) + ", getting another one")
@@ -66,99 +69,65 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 	}
 
 	if !dataFound || expired {
-		tryUntilSuccessful(ctx, logger, func() error {
-			data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway,
-				p.portForwardPath, p.authFilePath)
-			return err
-		})
-		if ctx.Err() != nil {
-			return
+		data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway,
+			p.portForwardPath, p.authFilePath)
+		if err != nil {
+			return 0, fmt.Errorf("%w: %s", ErrRefreshPortForwardData, err)
 		}
 		durationToExpiration = data.Expiration.Sub(p.timeNow())
 	}
-	logger.Info("Port forwarded is " + strconv.Itoa(int(data.Port)) +
-		" expiring in " + format.FriendlyDuration(durationToExpiration))
+	logger.Info("Port forwarded data expires in " + format.FriendlyDuration(durationToExpiration))
 
 	// First time binding
-	tryUntilSuccessful(ctx, logger, func() error {
-		if err := bindPort(ctx, privateIPClient, gateway, data); err != nil {
-			return fmt.Errorf("%w: %s", ErrBindPort, err)
-		}
-		return nil
-	})
-	if ctx.Err() != nil {
-		return
+	if err := bindPort(ctx, privateIPClient, gateway, data); err != nil {
+		return 0, fmt.Errorf("%w: %s", ErrBindPort, err)
 	}
 
-	filepath := syncState(data.Port)
-	logger.Info("Writing port to " + filepath)
-	if err := writePortForwardedToFile(filepath, data.Port); err != nil {
-		logger.Error(err.Error())
+	return data.Port, nil
+}
+
+var (
+	ErrPortForwardedExpired = errors.New("port forwarded data expired")
+)
+
+func (p *PIA) KeepPortForward(ctx context.Context, client *http.Client,
+	logger logging.Logger, port uint16, gateway net.IP, serverName string) (
+	err error) {
+	privateIPClient, err := newHTTPClient(serverName)
+	if err != nil {
+		return fmt.Errorf("%w: %s", ErrCreateHTTPClient, err)
 	}
 
-	if err := portAllower.SetAllowedPort(ctx, data.Port, string(constants.TUN)); err != nil {
-		logger.Error(err.Error())
+	data, err := readPIAPortForwardData(p.portForwardPath)
+	if err != nil {
+		return fmt.Errorf("%w: %s", ErrReadSavedPortForwardData, err)
 	}
 
+	durationToExpiration := data.Expiration.Sub(p.timeNow())
 	expiryTimer := time.NewTimer(durationToExpiration)
 	const keepAlivePeriod = 15 * time.Minute
 	// Timer behaving as a ticker
 	keepAliveTimer := time.NewTimer(keepAlivePeriod)
+
 	for {
 		select {
 		case <-ctx.Done():
-			removeCtx, cancel := context.WithTimeout(context.Background(), time.Second)
-			defer cancel()
-			if err := portAllower.RemoveAllowedPort(removeCtx, data.Port); err != nil {
-				logger.Error(err.Error())
-			}
 			if !keepAliveTimer.Stop() {
 				<-keepAliveTimer.C
 			}
 			if !expiryTimer.Stop() {
 				<-expiryTimer.C
 			}
-			return
+			return ctx.Err()
 		case <-keepAliveTimer.C:
-			if err := bindPort(ctx, privateIPClient, gateway, data); err != nil {
-				logger.Error("cannot bind port: " + err.Error())
+			err := bindPort(ctx, privateIPClient, gateway, data)
+			if err != nil {
+				return fmt.Errorf("%w: %s", ErrBindPort, err)
 			}
 			keepAliveTimer.Reset(keepAlivePeriod)
 		case <-expiryTimer.C:
-			logger.Warn("Forward port has expired on " +
-				data.Expiration.Format(time.RFC1123) + ", getting another one")
-			oldPort := data.Port
-			for {
-				data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway,
-					p.portForwardPath, p.authFilePath)
-				if err != nil {
-					logger.Error(err.Error())
-					continue
-				}
-				break
-			}
-			durationToExpiration := data.Expiration.Sub(p.timeNow())
-			logger.Info("Port forwarded is " + strconv.Itoa(int(data.Port)) +
-				" expiring in " + format.FriendlyDuration(durationToExpiration))
-			if err := portAllower.RemoveAllowedPort(ctx, oldPort); err != nil {
-				logger.Error(err.Error())
-			}
-			if err := portAllower.SetAllowedPort(ctx, data.Port, string(constants.TUN)); err != nil {
-				logger.Error(err.Error())
-			}
-			filepath := syncState(data.Port)
-			logger.Info("Writing port to " + filepath)
-			if err := writePortForwardedToFile(filepath, data.Port); err != nil {
-				logger.Error("Cannot write port forward data to file: " + err.Error())
-			}
-			if err := bindPort(ctx, privateIPClient, gateway, data); err != nil {
-				logger.Error("Cannot bind port: " + err.Error())
-			}
-			if !keepAliveTimer.Stop() {
-				<-keepAliveTimer.C
-			}
-			keepAliveTimer.Reset(keepAlivePeriod)
-			expiryTimer.Reset(durationToExpiration)
+			return fmt.Errorf("%w: on %s", ErrPortForwardedExpired,
+				data.Expiration.Format(time.RFC1123))
 		}
 	}
 }
@@ -463,21 +432,6 @@ func bindPort(ctx context.Context, client *http.Client, gateway net.IP, data pia
 	return nil
 }
 
-func writePortForwardedToFile(filepath string, port uint16) (err error) {
-	file, err := os.OpenFile(filepath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
-	if err != nil {
-		return err
-	}
-
-	_, err = file.Write([]byte(fmt.Sprintf("%d", port)))
-	if err != nil {
-		_ = file.Close()
-		return err
-	}
-
-	return file.Close()
-}
-
 // replaceInErr is used to remove sensitive information from errors.
 func replaceInErr(err error, substitutions map[string]string) error {
 	s := replaceInString(err.Error(), substitutions)

internal/provider/privateinternetaccess/try.go

@@ -1,31 +0,0 @@
-package privateinternetaccess
-
-import (
-	"context"
-	"time"
-
-	"github.com/qdm12/golibs/logging"
-)
-
-func tryUntilSuccessful(ctx context.Context, logger logging.Logger, fn func() error) {
-	const initialRetryPeriod = 5 * time.Second
-	retryPeriod := initialRetryPeriod
-	for {
-		err := fn()
-		if err == nil {
-			break
-		}
-		logger.Error(err.Error())
-		logger.Info("Trying again in " + retryPeriod.String())
-		timer := time.NewTimer(retryPeriod)
-		select {
-		case <-timer.C:
-		case <-ctx.Done():
-			if !timer.Stop() {
-				<-timer.C
-			}
-			return
-		}
-		retryPeriod *= 2
-	}
-}

internal/provider/provider.go

@@ -10,7 +10,6 @@ import (
 
 	"github.com/qdm12/gluetun/internal/configuration"
 	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/cyberghost"
 	"github.com/qdm12/gluetun/internal/provider/fastestvpn"
@@ -36,9 +35,16 @@ import (
 type Provider interface {
 	GetOpenVPNConnection(selection configuration.ServerSelection) (connection models.OpenVPNConnection, err error)
 	BuildConf(connection models.OpenVPNConnection, username string, settings configuration.OpenVPN) (lines []string)
+	PortForwarder
+}
+
+type PortForwarder interface {
 	PortForward(ctx context.Context, client *http.Client,
-		pfLogger logging.Logger, gateway net.IP, portAllower firewall.PortAllower,
-		syncState func(port uint16) (pfFilepath string))
+		logger logging.Logger, gateway net.IP, serverName string) (
+		port uint16, err error)
+	KeepPortForward(ctx context.Context, client *http.Client,
+		logger logging.Logger, port uint16, gateway net.IP, serverName string) (
+		err error)
 }
 
 func New(provider string, allServers models.AllServers, timeNow func() time.Time) Provider {

internal/provider/utils/noportforward.go

@@ -2,17 +2,21 @@ package utils
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"net"
 	"net/http"
 
-	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
 )
 
 type NoPortForwarder interface {
 	PortForward(ctx context.Context, client *http.Client,
-		pfLogger logging.Logger, gateway net.IP, portAllower firewall.PortAllower,
-		syncState func(port uint16) (pfFilepath string))
+		logger logging.Logger, gateway net.IP, serverName string) (
+		port uint16, err error)
+	KeepPortForward(ctx context.Context, client *http.Client,
+		logger logging.Logger, port uint16, gateway net.IP, serverName string) (
+		err error)
 }
 
 type NoPortForwarding struct {
@@ -25,8 +29,16 @@ func NewNoPortForwarding(providerName string) *NoPortForwarding {
 	}
 }
 
+var ErrPortForwardingNotSupported = errors.New("custom port forwarding obtention is not supported")
+
 func (n *NoPortForwarding) PortForward(ctx context.Context, client *http.Client,
-	pfLogger logging.Logger, gateway net.IP, portAllower firewall.PortAllower,
-	syncState func(port uint16) (pfFilepath string)) {
-	panic("custom port forwarding obtention is not supported for " + n.providerName)
+	logger logging.Logger, gateway net.IP, serverName string) (
+	port uint16, err error) {
+	return 0, fmt.Errorf("%w: for %s", ErrPortForwardingNotSupported, n.providerName)
+}
+
+func (n *NoPortForwarding) KeepPortForward(ctx context.Context, client *http.Client,
+	logger logging.Logger, port uint16, gateway net.IP, serverName string) (
+	err error) {
+	return fmt.Errorf("%w: for %s", ErrPortForwardingNotSupported, n.providerName)
 }

internal/server/openvpn.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/openvpn"
+	"github.com/qdm12/gluetun/internal/portforward"
 	"github.com/qdm12/golibs/logging"
 )
 
@@ -22,6 +23,7 @@ func newOpenvpnHandler(ctx context.Context, looper openvpn.Looper,
 type openvpnHandler struct {
 	ctx    context.Context
 	looper openvpn.Looper
+	pf     portforward.Getter
 	logger logging.Logger
 }
 
@@ -105,7 +107,7 @@ func (h *openvpnHandler) getSettings(w http.ResponseWriter) {
 }
 
 func (h *openvpnHandler) getPortForwarded(w http.ResponseWriter) {
-	port := h.looper.GetPortForwarded()
+	port := h.pf.GetPortForwarded()
 	encoder := json.NewEncoder(w)
 	data := portWrapper{Port: port}
 	if err := encoder.Encode(data); err != nil {