feat(wireguard): WIREGUARD_IMPLEMENTATION variable

- Can be `auto` (default), `userspace` or `kernelspace`

Dockerfile

@@ -97,6 +97,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     WIREGUARD_PRESHARED_KEY= \
     WIREGUARD_PUBLIC_KEY= \
     WIREGUARD_ADDRESSES= \
+    WIREGUARD_IMPLEMENTATION=auto \
     # VPN server filtering
     SERVER_REGIONS= \
     SERVER_COUNTRIES= \

internal/configuration/settings/errors.go

@@ -44,4 +44,5 @@ var (
 	ErrWireguardPrivateKeyNotSet       = errors.New("private key is not set")
 	ErrWireguardPublicKeyNotSet        = errors.New("public key is not set")
 	ErrWireguardPublicKeyNotValid      = errors.New("public key is not valid")
+	ErrWireguardImplementationNotValid = errors.New("implementation is not valid")
 )

internal/configuration/settings/wireguard.go

@@ -27,6 +27,11 @@ type Wireguard struct {
 	// to create. It cannot be the empty string in the
 	// internal state.
 	Interface string
+	// Implementation is the Wireguard implementation to use.
+	// It can be "auto", "userspace" or "kernelspace".
+	// It defaults to "auto" and cannot be the empty string
+	// in the internal state.
+	Implementation string
 }
 
 var regexpInterfaceName = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
@@ -85,6 +90,12 @@ func (w Wireguard) validate(vpnProvider string) (err error) {
 			ErrWireguardInterfaceNotValid, w.Interface, regexpInterfaceName)
 	}
 
+	validImplementations := []string{"auto", "userspace", "kernelspace"}
+	if !helpers.IsOneOf(w.Implementation, validImplementations...) {
+		return fmt.Errorf("%w: %s must be one of %s", ErrWireguardImplementationNotValid,
+			w.Implementation, helpers.ChoicesOrString(validImplementations))
+	}
+
 	return nil
 }
 
@@ -94,6 +105,7 @@ func (w *Wireguard) copy() (copied Wireguard) {
 		PreSharedKey:   helpers.CopyStringPtr(w.PreSharedKey),
 		Addresses:      helpers.CopyIPNetSlice(w.Addresses),
 		Interface:      w.Interface,
+		Implementation: w.Implementation,
 	}
 }
 
@@ -102,6 +114,7 @@ func (w *Wireguard) mergeWith(other Wireguard) {
 	w.PreSharedKey = helpers.MergeWithStringPtr(w.PreSharedKey, other.PreSharedKey)
 	w.Addresses = helpers.MergeIPNetsSlices(w.Addresses, other.Addresses)
 	w.Interface = helpers.MergeWithString(w.Interface, other.Interface)
+	w.Implementation = helpers.MergeWithString(w.Implementation, other.Implementation)
 }
 
 func (w *Wireguard) overrideWith(other Wireguard) {
@@ -109,12 +122,14 @@ func (w *Wireguard) overrideWith(other Wireguard) {
 	w.PreSharedKey = helpers.OverrideWithStringPtr(w.PreSharedKey, other.PreSharedKey)
 	w.Addresses = helpers.OverrideWithIPNetsSlice(w.Addresses, other.Addresses)
 	w.Interface = helpers.OverrideWithString(w.Interface, other.Interface)
+	w.Implementation = helpers.OverrideWithString(w.Implementation, other.Implementation)
 }
 
 func (w *Wireguard) setDefaults() {
 	w.PrivateKey = helpers.DefaultStringPtr(w.PrivateKey, "")
 	w.PreSharedKey = helpers.DefaultStringPtr(w.PreSharedKey, "")
 	w.Interface = helpers.DefaultString(w.Interface, "wg0")
+	w.Implementation = helpers.DefaultString(w.Implementation, "auto")
 }
 
 func (w Wireguard) String() string {
@@ -141,5 +156,9 @@ func (w Wireguard) toLinesNode() (node *gotree.Node) {
 
 	node.Appendf("Network interface: %s", w.Interface)
 
+	if w.Implementation != "auto" {
+		node.Appendf("Implementation: %s", w.Implementation)
+	}
+
 	return node
 }

internal/configuration/sources/env/wireguard.go

@@ -3,6 +3,7 @@ package env
 import (
 	"fmt"
 	"net"
+	"os"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
@@ -15,6 +16,7 @@ func (s *Source) readWireguard() (wireguard settings.Wireguard, err error) {
 	wireguard.PrivateKey = envToStringPtr("WIREGUARD_PRIVATE_KEY")
 	wireguard.PreSharedKey = envToStringPtr("WIREGUARD_PRESHARED_KEY")
 	_, wireguard.Interface = s.getEnvWithRetro("VPN_INTERFACE", "WIREGUARD_INTERFACE")
+	wireguard.Implementation = os.Getenv("WIREGUARD_IMPLEMENTATION")
 	wireguard.Addresses, err = s.readWireguardAddresses()
 	if err != nil {
 		return wireguard, err // already wrapped

internal/provider/utils/wireguard.go

@@ -14,6 +14,7 @@ func BuildWireguardSettings(connection models.Connection,
 	settings.PublicKey = connection.PubKey
 	settings.PreSharedKey = *userSettings.PreSharedKey
 	settings.InterfaceName = userSettings.Interface
+	settings.Implementation = userSettings.Implementation
 	settings.IPv6 = &ipv6Supported
 
 	const rulePriority = 101 // 100 is to receive external connections

internal/wireguard/constructor_test.go

@@ -56,6 +56,7 @@ func Test_New(t *testing.T) {
 					},
 					FirewallMark:   100,
 					IPv6:           ptr(false),
+					Implementation: "auto",
 				},
 			},
 		},

internal/wireguard/run.go

@@ -31,16 +31,37 @@ var (
 	ErrIfaceUp           = errors.New("cannot set the interface to UP")
 	ErrRouteAdd          = errors.New("cannot add route for interface")
 	ErrDeviceWaited      = errors.New("device waited for")
+	ErrKernelSupport     = errors.New("kernel does not support Wireguard")
 )
 
 // See https://git.zx2c4.com/wireguard-go/tree/main.go
 func (w *Wireguard) Run(ctx context.Context, waitError chan<- error, ready chan<- struct{}) {
-	doKernel, err := w.netlink.IsWireguardSupported()
+	kernelSupported, err := w.netlink.IsWireguardSupported()
 	if err != nil {
 		waitError <- fmt.Errorf("%w: %s", ErrDetectKernel, err)
 		return
 	}
 
+	setupFunction := setupUserSpace
+	switch w.settings.Implementation {
+	case "auto": //nolint:goconst
+		if !kernelSupported {
+			w.logger.Info("Using userspace implementation since Kernel support does not exist")
+			break
+		}
+		w.logger.Info("Using available kernelspace implementation")
+		setupFunction = setupKernelSpace
+	case "userspace":
+	case "kernelspace":
+		if !kernelSupported {
+			waitError <- fmt.Errorf("%w", ErrKernelSupport)
+			return
+		}
+		setupFunction = setupKernelSpace
+	default:
+		panic(fmt.Sprintf("unknown implementation %q", w.settings.Implementation))
+	}
+
 	client, err := wgctrl.New()
 	if err != nil {
 		waitError <- fmt.Errorf("%w: %s", ErrWgctrlOpen, err)
@@ -52,14 +73,6 @@ func (w *Wireguard) Run(ctx context.Context, waitError chan<- error, ready chan<
 
 	defer closers.cleanup(w.logger)
 
-	setupFunction := setupUserSpace
-	if doKernel {
-		w.logger.Info("Using available kernelspace implementation")
-		setupFunction = setupKernelSpace
-	} else {
-		w.logger.Info("Using userspace implementation since Kernel support does not exist")
-	}
-
 	link, waitAndCleanup, err := setupFunction(ctx,
 		w.settings.InterfaceName, w.netlink, &closers, w.logger)
 	if err != nil {

internal/wireguard/settings.go

@@ -33,6 +33,9 @@ type Settings struct {
 	// IPv6 can bet set to true if IPv6 should be handled.
 	// It defaults to false if left unset.
 	IPv6 *bool
+	// Implementation is the implementation to use.
+	// It can be auto, kernelspace or userspace, and defaults to auto.
+	Implementation string
 }
 
 func (s *Settings) SetDefaults() {
@@ -55,6 +58,11 @@ func (s *Settings) SetDefaults() {
 		ipv6 := false // this should be injected from host
 		s.IPv6 = &ipv6
 	}
+
+	if s.Implementation == "" {
+		const defaultImplementation = "auto"
+		s.Implementation = defaultImplementation
+	}
 }
 
 var (
@@ -72,6 +80,7 @@ var (
 	ErrAddressIPMissing      = errors.New("interface address IP is missing")
 	ErrAddressMaskMissing    = errors.New("interface address mask is missing")
 	ErrFirewallMarkMissing   = errors.New("firewall mark is missing")
+	ErrImplementationInvalid = errors.New("invalid implementation")
 )
 
 var interfaceNameRegexp = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
@@ -129,6 +138,12 @@ func (s *Settings) Check() (err error) {
 		return ErrFirewallMarkMissing
 	}
 
+	switch s.Implementation {
+	case "auto", "kernelspace", "userspace":
+	default:
+		return fmt.Errorf("%w: %s", ErrImplementationInvalid, s.Implementation)
+	}
+
 	return nil
 }
 
@@ -209,6 +224,10 @@ func (s Settings) ToLines(settings ToLinesSettings) (lines []string) {
 		lines = append(lines, fieldPrefix+"Rule priority: "+fmt.Sprint(s.RulePriority))
 	}
 
+	if s.Implementation != "auto" {
+		lines = append(lines, fieldPrefix+"Implementation: "+s.Implementation)
+	}
+
 	if len(s.Addresses) == 0 {
 		lines = append(lines, lastFieldPrefix+"Addresses: "+notSet)
 	} else {

internal/wireguard/settings_test.go

@@ -23,6 +23,7 @@ func Test_Settings_SetDefaults(t *testing.T) {
 				InterfaceName:  "wg0",
 				FirewallMark:   51820,
 				IPv6:           ptr(false),
+				Implementation: "auto",
 			},
 		},
 		"default endpoint port": {
@@ -39,6 +40,7 @@ func Test_Settings_SetDefaults(t *testing.T) {
 					Port: 51820,
 				},
 				IPv6:           ptr(false),
+				Implementation: "auto",
 			},
 		},
 		"not empty settings": {
@@ -50,6 +52,7 @@ func Test_Settings_SetDefaults(t *testing.T) {
 					Port: 9999,
 				},
 				IPv6:           ptr(true),
+				Implementation: "userspace",
 			},
 			expected: Settings{
 				InterfaceName: "wg1",
@@ -59,6 +62,7 @@ func Test_Settings_SetDefaults(t *testing.T) {
 					Port: 9999,
 				},
 				IPv6:           ptr(true),
+				Implementation: "userspace",
 			},
 		},
 	}
@@ -225,6 +229,21 @@ func Test_Settings_Check(t *testing.T) {
 			},
 			err: ErrFirewallMarkMissing,
 		},
+		"invalid implementation": {
+			settings: Settings{
+				InterfaceName: "wg0",
+				PrivateKey:    validKey1,
+				PublicKey:     validKey2,
+				Endpoint: &net.UDPAddr{
+					IP:   net.IPv4(1, 2, 3, 4),
+					Port: 51820,
+				},
+				Addresses:      []*net.IPNet{{IP: net.IPv4(1, 2, 3, 4), Mask: net.CIDRMask(24, 32)}},
+				FirewallMark:   999,
+				Implementation: "x",
+			},
+			err: errors.New("invalid implementation: x"),
+		},
 		"all valid": {
 			settings: Settings{
 				InterfaceName: "wg0",
@@ -236,6 +255,7 @@ func Test_Settings_Check(t *testing.T) {
 				},
 				Addresses:      []*net.IPNet{{IP: net.IPv4(1, 2, 3, 4), Mask: net.CIDRMask(24, 32)}},
 				FirewallMark:   999,
+				Implementation: "userspace",
 			},
 		},
 	}
@@ -289,12 +309,14 @@ func Test_Settings_String(t *testing.T) {
 	settings := Settings{
 		InterfaceName:  "wg0",
 		IPv6:           ptr(true),
+		Implementation: "x",
 	}
 	const expected = `├── Interface name: wg0
 ├── Private key: not set
 ├── Pre shared key: not set
 ├── Endpoint: not set
 ├── IPv6: enabled
+├── Implementation: x
 └── Addresses: not set`
 	s := settings.String()
 	assert.Equal(t, expected, s)
@@ -318,6 +340,7 @@ func Test_Settings_Lines(t *testing.T) {
 				"├── Pre shared key: not set",
 				"├── Endpoint: not set",
 				"├── IPv6: disabled",
+				"├── Implementation: ",
 				"└── Addresses: not set",
 			},
 		},
@@ -338,6 +361,7 @@ func Test_Settings_Lines(t *testing.T) {
 					{IP: net.IPv4(2, 2, 2, 2), Mask: net.CIDRMask(32, 32)},
 				},
 				IPv6:           ptr(true),
+				Implementation: "userspace",
 			},
 			lines: []string{
 				"├── Interface name: wg0",
@@ -348,6 +372,7 @@ func Test_Settings_Lines(t *testing.T) {
 				"├── IPv6: enabled",
 				"├── Firewall mark: 999",
 				"├── Rule priority: 888",
+				"├── Implementation: userspace",
 				"└── Addresses:",
 				"    ├── 1.1.1.1/24",
 				"    └── 2.2.2.2/32",
@@ -373,6 +398,7 @@ func Test_Settings_Lines(t *testing.T) {
 				"- Pre shared key: not set",
 				"- Endpoint: not set",
 				"- IPv6: disabled",
+				"- Implementation: ",
 				"* Addresses:",
 				"  - 1.1.1.1/24",
 				"  * 2.2.2.2/32",