feat(openvpn): add support for openvpn 2.6

Dockerfile

@@ -200,6 +200,9 @@ EXPOSE 8000/tcp 8888/tcp 8388/tcp 8388/udp
 HEALTHCHECK --interval=5s --timeout=5s --start-period=10s --retries=1 CMD /gluetun-entrypoint healthcheck
 ARG TARGETPLATFORM
 RUN apk add --no-cache --update -l wget && \
+    apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.18/main" openvpn\~2.6 && \
+    mv /usr/sbin/openvpn /usr/sbin/openvpn2.6 && \
+    apk del openvpn && \
     apk add --no-cache --update openvpn ca-certificates iptables ip6tables unbound tzdata && \
     mv /usr/sbin/openvpn /usr/sbin/openvpn2.5 && \
     # Fix vulnerability issue

README.md

@@ -57,7 +57,7 @@ Lightweight swiss-knife-like VPN client to multiple VPN service providers
 
 ## Features
 
-- Based on Alpine 3.17 for a small Docker image of 39.1MB
+- Based on Alpine 3.17 for a small Docker image of 39.8MB
 - Supports: **AirVPN**, **Cyberghost**, **ExpressVPN**, **FastestVPN**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad**, **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **WeVPN**, **Windscribe** servers
 - Supports OpenVPN for all providers listed
 - Supports Wireguard both kernelspace and userspace

cmd/gluetun/main.go

@@ -265,6 +265,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	err = printVersions(ctx, logger, []printVersionElement{
 		{name: "Alpine", getVersion: alpineConf.Version},
 		{name: "OpenVPN 2.5", getVersion: ovpnConf.Version25},
+		{name: "OpenVPN 2.6", getVersion: ovpnConf.Version26},
 		{name: "Unbound", getVersion: dnsConf.Version},
 		{name: "IPtables", getVersion: func(ctx context.Context) (version string, err error) {
 			return firewall.Version(ctx, cmder)

internal/configuration/settings/openvpn.go

@@ -17,7 +17,7 @@ import (
 // OpenVPN contains settings to configure the OpenVPN client.
 type OpenVPN struct {
 	// Version is the OpenVPN version to run.
-	// It can only be "2.5".
+	// It can only be "2.5" or "2.6".
 	Version string
 	// User is the OpenVPN authentication username.
 	// It cannot be nil in the internal state if OpenVPN is used.
@@ -88,7 +88,7 @@ var ivpnAccountID = regexp.MustCompile(`^(i|ivpn)\-[a-zA-Z0-9]{4}\-[a-zA-Z0-9]{4
 
 func (o OpenVPN) validate(vpnProvider string) (err error) {
 	// Validate version
-	validVersions := []string{openvpn.Openvpn25}
+	validVersions := []string{openvpn.Openvpn25, openvpn.Openvpn26}
 	if !helpers.IsOneOf(o.Version, validVersions...) {
 		return fmt.Errorf("%w: %q can only be one of %s",
 			ErrOpenVPNVersionIsNotValid, o.Version, strings.Join(validVersions, ", "))

internal/constants/openvpn/versions.go

@@ -2,4 +2,5 @@ package openvpn
 
 const (
 	Openvpn25 = "2.5"
+	Openvpn26 = "2.6"
 )

internal/openvpn/start.go

@@ -15,6 +15,7 @@ var ErrVersionUnknown = errors.New("OpenVPN version is unknown")
 
 const (
 	binOpenvpn25 = "openvpn2.5"
+	binOpenvpn26 = "openvpn2.6"
 )
 
 func start(ctx context.Context, starter command.Starter, version string, flags []string) (
@@ -23,6 +24,8 @@ func start(ctx context.Context, starter command.Starter, version string, flags [
 	switch version {
 	case openvpn.Openvpn25:
 		bin = binOpenvpn25
+	case openvpn.Openvpn26:
+		bin = binOpenvpn26
 	default:
 		return nil, nil, nil, fmt.Errorf("%w: %s", ErrVersionUnknown, version)
 	}

internal/openvpn/version.go

@@ -12,6 +12,10 @@ func (c *Configurator) Version25(ctx context.Context) (version string, err error
 	return c.version(ctx, binOpenvpn25)
 }
 
+func (c *Configurator) Version26(ctx context.Context) (version string, err error) {
+	return c.version(ctx, binOpenvpn26)
+}
+
 var ErrVersionTooShort = errors.New("version output is too short")
 
 func (c *Configurator) version(ctx context.Context, binName string) (version string, err error) {

internal/provider/airvpn/openvpnconf.go

@@ -24,7 +24,7 @@ func (p *Provider) OpenVPNConfig(connection models.Connection,
 	}
 
 	switch settings.Version {
-	case openvpn.Openvpn25:
+	case openvpn.Openvpn25, openvpn.Openvpn26:
 		providerSettings.Ciphers = []string{
 			openvpn.AES256gcm, openvpn.AES256cbc, openvpn.AES192gcm,
 			openvpn.AES192cbc, openvpn.AES128gcm, openvpn.AES128cbc,