feat(vpn): VPN_UP_COMMAND and VPN_DOWN_COMMAND options

cmd/gluetun/main.go

@@ -634,6 +634,8 @@ type RunStarter interface {
 	Run(cmd *exec.Cmd) (output string, err error)
 	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,
 		waitError <-chan error, err error)
+	RunAndLog(ctx context.Context, commandString string,
+		logger command.Logger) (err error)
 }
 
 const gluetunLogo = `                         @@@

internal/command/interfaces.go

@@ -0,0 +1,6 @@
+package command
+
+type Logger interface {
+	Info(s string)
+	Error(s string)
+}

internal/command/split.go

@@ -9,13 +9,13 @@ import (
 )
 
 var (
-	ErrCommandEmpty            = errors.New("command is empty")
-	ErrSingleQuoteUnterminated = errors.New("unterminated single-quoted string")
-	ErrDoubleQuoteUnterminated = errors.New("unterminated double-quoted string")
-	ErrEscapeUnterminated      = errors.New("unterminated backslash-escape")
+	errCommandEmpty            = errors.New("command is empty")
+	errSingleQuoteUnterminated = errors.New("unterminated single-quoted string")
+	errDoubleQuoteUnterminated = errors.New("unterminated double-quoted string")
+	errEscapeUnterminated      = errors.New("unterminated backslash-escape")
 )
 
-// Split splits a command string into a slice of arguments.
+// split splits a command string into a slice of arguments.
 // This is especially important for commands such as:
 // /bin/sh -c "echo hello"
 // which should be split into: ["/bin/sh", "-c", "echo hello"]
@@ -23,9 +23,9 @@ var (
 // It does not support:
 // - the $" quoting style.
 // - expansion (brace, shell or pathname).
-func Split(command string) (words []string, err error) {
+func split(command string) (words []string, err error) {
 	if command == "" {
-		return nil, fmt.Errorf("%w", ErrCommandEmpty)
+		return nil, fmt.Errorf("%w", errCommandEmpty)
 	}
 
 	const bufferSize = 1024
@@ -42,7 +42,7 @@ func Split(command string) (words []string, err error) {
 		case character == '\\':
 			// Look ahead to eventually skip an escaped newline
 			if command[startIndex+runeSize:] == "" {
-				return nil, fmt.Errorf("%w: %q", ErrEscapeUnterminated, command)
+				return nil, fmt.Errorf("%w: %q", errEscapeUnterminated, command)
 			}
 			character, runeSize := utf8.DecodeRuneInString(command[startIndex+runeSize:])
 			if character == '\n' {
@@ -119,7 +119,7 @@ func handleDoubleQuoted(input string, startIndex int, buffer *bytes.Buffer) (
 			startIndex = cursor
 		}
 	}
-	return "", 0, fmt.Errorf("%w", ErrDoubleQuoteUnterminated)
+	return "", 0, fmt.Errorf("%w", errDoubleQuoteUnterminated)
 }
 
 func handleSingleQuoted(input string, startIndex int, buffer *bytes.Buffer) (
@@ -127,7 +127,7 @@ func handleSingleQuoted(input string, startIndex int, buffer *bytes.Buffer) (
 ) {
 	closingQuoteIndex := strings.IndexRune(input[startIndex:], '\'')
 	if closingQuoteIndex == -1 {
-		return "", 0, fmt.Errorf("%w", ErrSingleQuoteUnterminated)
+		return "", 0, fmt.Errorf("%w", errSingleQuoteUnterminated)
 	}
 	buffer.WriteString(input[startIndex : startIndex+closingQuoteIndex])
 	const singleQuoteRuneLength = 1
@@ -139,7 +139,7 @@ func handleEscaped(input string, startIndex int, buffer *bytes.Buffer) (
 	word string, newStartIndex int, err error,
 ) {
 	if input[startIndex:] == "" {
-		return "", 0, fmt.Errorf("%w", ErrEscapeUnterminated)
+		return "", 0, fmt.Errorf("%w", errEscapeUnterminated)
 	}
 	character, runeLength := utf8.DecodeRuneInString(input[startIndex:])
 	if character != '\n' { // backslash-escaped newline is ignored

internal/command/split_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func Test_Split(t *testing.T) {
+func Test_split(t *testing.T) {
 	t.Parallel()
 
 	testCases := map[string]struct {
@@ -17,7 +17,7 @@ func Test_Split(t *testing.T) {
 	}{
 		"empty": {
 			command:    "",
-			errWrapped: ErrCommandEmpty,
+			errWrapped: errCommandEmpty,
 			errMessage: "command is empty",
 		},
 		"concrete_sh_command": {
@@ -74,22 +74,22 @@ func Test_Split(t *testing.T) {
 		},
 		"unterminated_single_quote": {
 			command:    "'abc'\\''def",
-			errWrapped: ErrSingleQuoteUnterminated,
+			errWrapped: errSingleQuoteUnterminated,
 			errMessage: `splitting word in "'abc'\\''def": unterminated single-quoted string`,
 		},
 		"unterminated_double_quote": {
 			command:    "\"abc'def",
-			errWrapped: ErrDoubleQuoteUnterminated,
+			errWrapped: errDoubleQuoteUnterminated,
 			errMessage: `splitting word in "\"abc'def": unterminated double-quoted string`,
 		},
 		"unterminated_escape": {
 			command:    "abc\\",
-			errWrapped: ErrEscapeUnterminated,
+			errWrapped: errEscapeUnterminated,
 			errMessage: `splitting word in "abc\\": unterminated backslash-escape`,
 		},
 		"unterminated_escape_only": {
 			command:    "   \\",
-			errWrapped: ErrEscapeUnterminated,
+			errWrapped: errEscapeUnterminated,
 			errMessage: `unterminated backslash-escape: "   \\"`,
 		},
 	}
@@ -98,7 +98,7 @@ func Test_Split(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 
-			words, err := Split(testCase.command)
+			words, err := split(testCase.command)
 
 			assert.Equal(t, testCase.words, words)
 			assert.ErrorIs(t, err, testCase.errWrapped)

internal/command/startnlog.go

@@ -0,0 +1,48 @@
+package command
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+)
+
+func (c *Cmder) RunAndLog(ctx context.Context, command string, logger Logger) (err error) {
+	args, err := split(command)
+	if err != nil {
+		return fmt.Errorf("parsing command: %w", err)
+	}
+
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...) // #nosec G204
+	stdout, stderr, waitError, err := c.Start(cmd)
+	if err != nil {
+		return err
+	}
+
+	streamCtx, streamCancel := context.WithCancel(context.Background())
+	streamDone := make(chan struct{})
+	go streamLines(streamCtx, streamDone, logger, stdout, stderr)
+
+	err = <-waitError
+	streamCancel()
+	<-streamDone
+	return err
+}
+
+func streamLines(ctx context.Context, done chan<- struct{},
+	logger Logger, stdout, stderr <-chan string,
+) {
+	defer close(done)
+
+	var line string
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case line = <-stdout:
+			logger.Info(line)
+		case line = <-stderr:
+			logger.Error(line)
+		}
+	}
+}

internal/configuration/settings/vpn.go

@@ -19,6 +19,14 @@ type VPN struct {
 	OpenVPN   OpenVPN   `json:"openvpn"`
 	Wireguard Wireguard `json:"wireguard"`
 	PMTUD     PMTUD     `json:"pmtud"`
+	// UpCommand is the command to use when the VPN connection is up.
+	// It can be the empty string to indicate not to run a command.
+	// It cannot be nil in the internal state.
+	UpCommand *string `json:"up_command"`
+	// DownCommand is the command to use after the VPN connection goes down.
+	// It can be the empty string to indicate to NOT run a command.
+	// It cannot be nil in the internal state.
+	DownCommand *string `json:"down_command"`
 }
 
 // TODO v4 remove pointer for receiver (because of Surfshark).
@@ -56,11 +64,13 @@ func (v *VPN) Validate(filterChoicesGetter FilterChoicesGetter, ipv6Supported bo
 
 func (v *VPN) Copy() (copied VPN) {
 	return VPN{
-		Type:      v.Type,
-		Provider:  v.Provider.copy(),
-		OpenVPN:   v.OpenVPN.copy(),
-		Wireguard: v.Wireguard.copy(),
-		PMTUD:     v.PMTUD.copy(),
+		Type:        v.Type,
+		Provider:    v.Provider.copy(),
+		OpenVPN:     v.OpenVPN.copy(),
+		Wireguard:   v.Wireguard.copy(),
+		PMTUD:       v.PMTUD.copy(),
+		UpCommand:   gosettings.CopyPointer(v.UpCommand),
+		DownCommand: gosettings.CopyPointer(v.DownCommand),
 	}
 }
 
@@ -70,6 +80,8 @@ func (v *VPN) OverrideWith(other VPN) {
 	v.OpenVPN.overrideWith(other.OpenVPN)
 	v.Wireguard.overrideWith(other.Wireguard)
 	v.PMTUD.overrideWith(other.PMTUD)
+	v.UpCommand = gosettings.OverrideWithPointer(v.UpCommand, other.UpCommand)
+	v.DownCommand = gosettings.OverrideWithPointer(v.DownCommand, other.DownCommand)
 }
 
 func (v *VPN) setDefaults() {
@@ -78,6 +90,8 @@ func (v *VPN) setDefaults() {
 	v.OpenVPN.setDefaults(v.Provider.Name)
 	v.Wireguard.setDefaults(v.Provider.Name)
 	v.PMTUD.setDefaults()
+	v.UpCommand = gosettings.DefaultPointer(v.UpCommand, "")
+	v.DownCommand = gosettings.DefaultPointer(v.DownCommand, "")
 }
 
 func (v VPN) String() string {
@@ -96,6 +110,13 @@ func (v VPN) toLinesNode() (node *gotree.Node) {
 	}
 	node.AppendNode(v.PMTUD.toLinesNode())
 
+	if *v.UpCommand != "" {
+		node.Appendf("Up command: %s", *v.UpCommand)
+	}
+	if *v.DownCommand != "" {
+		node.Appendf("Down command: %s", *v.DownCommand)
+	}
+
 	return node
 }
 
@@ -122,5 +143,9 @@ func (v *VPN) read(r *reader.Reader) (err error) {
 		return fmt.Errorf("PMTUD: %w", err)
 	}
 
+	v.UpCommand = r.Get("VPN_UP_COMMAND", reader.ForceLowercase(false))
+
+	v.DownCommand = r.Get("VPN_DOWN_COMMAND", reader.ForceLowercase(false))
+
 	return nil
 }

internal/portforward/interfaces.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"net/netip"
 	"os/exec"
+
+	"github.com/qdm12/gluetun/internal/command"
 )
 
 type Service interface {
@@ -35,4 +37,5 @@ type Logger interface {
 type Cmder interface {
 	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,
 		waitError <-chan error, startErr error)
+	RunAndLog(ctx context.Context, commandString string, logger command.Logger) (err error)
 }

internal/portforward/service/command.go

@@ -3,10 +3,7 @@ package service
 import (
 	"context"
 	"fmt"
-	"os/exec"
 	"strings"
-
-	"github.com/qdm12/gluetun/internal/command"
 )
 
 func runCommand(ctx context.Context, cmder Cmder, logger Logger,
@@ -20,42 +17,5 @@ func runCommand(ctx context.Context, cmder Cmder, logger Logger,
 	commandString := strings.ReplaceAll(commandTemplate, "{{PORTS}}", portsString)
 	commandString = strings.ReplaceAll(commandString, "{{PORT}}", portStrings[0])
 	commandString = strings.ReplaceAll(commandString, "{{VPN_INTERFACE}}", vpnInterface)
-	args, err := command.Split(commandString)
-	if err != nil {
-		return fmt.Errorf("parsing command: %w", err)
-	}
-
-	cmd := exec.CommandContext(ctx, args[0], args[1:]...) // #nosec G204
-	stdout, stderr, waitError, err := cmder.Start(cmd)
-	if err != nil {
-		return err
-	}
-
-	streamCtx, streamCancel := context.WithCancel(context.Background())
-	streamDone := make(chan struct{})
-	go streamLines(streamCtx, streamDone, logger, stdout, stderr)
-
-	err = <-waitError
-	streamCancel()
-	<-streamDone
-	return err
-}
-
-func streamLines(ctx context.Context, done chan<- struct{},
-	logger Logger, stdout, stderr <-chan string,
-) {
-	defer close(done)
-
-	var line string
-
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		case line = <-stdout:
-			logger.Info(line)
-		case line = <-stderr:
-			logger.Error(line)
-		}
-	}
+	return cmder.RunAndLog(ctx, commandString, logger)
 }

internal/portforward/service/interfaces.go

@@ -3,8 +3,8 @@ package service
 import (
 	"context"
 	"net/netip"
-	"os/exec"
 
+	"github.com/qdm12/gluetun/internal/command"
 	"github.com/qdm12/gluetun/internal/provider/utils"
 )
 
@@ -35,6 +35,5 @@ type PortForwarder interface {
 }
 
 type Cmder interface {
-	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,
-		waitError <-chan error, startErr error)
+	RunAndLog(ctx context.Context, command string, logger command.Logger) (err error)
 }

internal/vpn/cleanup.go

@@ -3,9 +3,22 @@ package vpn
 import (
 	"context"
 	"errors"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants/vpn"
 )
 
 func (l *Loop) cleanup() {
+	settings := l.GetSettings()
+
+	var err error
+	commandString := strings.ReplaceAll(*settings.DownCommand, "{{VPN_INTERFACE}}", getVPNInterface(settings))
+	err = l.cmder.RunAndLog(context.Background(), commandString, l.logger)
+	if err != nil {
+		l.logger.Error("failed to run VPN down command: " + err.Error())
+	}
+
 	for _, vpnPort := range l.vpnInputPorts {
 		err := l.fw.RemoveAllowedPort(context.Background(), vpnPort)
 		if err != nil {
@@ -13,7 +26,7 @@ func (l *Loop) cleanup() {
 		}
 	}
 
-	err := l.publicip.ClearData()
+	err = l.publicip.ClearData()
 	if err != nil {
 		l.logger.Error("clearing public IP data: " + err.Error())
 	}
@@ -31,3 +44,14 @@ func (l *Loop) cleanup() {
 		l.logger.Error("stopping boring poll: " + err.Error())
 	}
 }
+
+func getVPNInterface(settings settings.VPN) string {
+	switch settings.Type {
+	case vpn.OpenVPN:
+		return settings.OpenVPN.Interface
+	case vpn.Wireguard:
+		return settings.Wireguard.Interface
+	default:
+		panic("invalid VPN type: " + settings.Type)
+	}
+}

internal/vpn/interfaces.go

@@ -5,6 +5,7 @@ import (
 	"net/netip"
 	"os/exec"
 
+	"github.com/qdm12/gluetun/internal/command"
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/netlink"
@@ -120,3 +121,7 @@ type Service interface {
 	Start() (runError <-chan error, err error)
 	Stop() error
 }
+
+type Cmder interface {
+	RunAndLog(ctx context.Context, command string, logger command.Logger) (err error)
+}

internal/vpn/loop.go

@@ -17,6 +17,7 @@ type Loop struct {
 	state          *state.State
 	providers      Providers
 	storage        Storage
+	cmder          Cmder
 	healthSettings settings.Health
 	healthChecker  HealthChecker
 	healthServer   HealthServer

internal/vpn/run.go

@@ -47,6 +47,7 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			continue
 		}
 		tunnelUpData := tunnelUpData{
+			upCommand: *settings.UpCommand,
 			pmtud: tunnelUpPMTUDData{
 				enabled:   settings.Type != vpn.Wireguard || *settings.Wireguard.MTU == 0,
 				vpnType:   settings.Type,

internal/vpn/tunnelup.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/netip"
+	"strings"
 	"time"
 
 	"github.com/qdm12/gluetun/internal/constants"
@@ -16,6 +17,7 @@ import (
 )
 
 type tunnelUpData struct {
+	upCommand string
 	// Healthcheck
 	serverIP netip.Addr
 	pmtud    tunnelUpPMTUDData
@@ -107,6 +109,14 @@ func (l *Loop) onTunnelUp(ctx, loopCtx context.Context, data tunnelUpData) {
 		}
 	}
 
+	if data.upCommand != "" {
+		commandString := strings.ReplaceAll(data.upCommand, "{{VPN_INTERFACE}}", data.vpnIntf)
+		err := l.cmder.RunAndLog(context.Background(), commandString, l.logger)
+		if err != nil {
+			l.logger.Error("failed to run VPN up command: " + err.Error())
+		}
+	}
+
 	err = l.startPortForwarding(data)
 	if err != nil {
 		l.logger.Error(err.Error())