chore(all): make code compilable for other platforms than Linux

cmd/gluetun/main.go

@@ -581,7 +581,7 @@ type Linker interface {
 	LinkDel(link netlink.Link) (err error)
 	LinkSetUp(link netlink.Link) (linkIndex int, err error)
 	LinkSetDown(link netlink.Link) (err error)
-	LinkSetMTU(link netlink.Link, mtu int) error
+	LinkSetMTU(link netlink.Link, mtu uint32) error
 }
 
 type clier interface {

internal/netlink/address.go

@@ -1,5 +1,3 @@
-//go:build linux || darwin
-
 package netlink
 
 import (

internal/netlink/address_unspecified.go

@@ -1,13 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) AddrList(link Link, family int) (
-	addresses []Addr, err error,
-) {
-	panic("not implemented")
-}
-
-func (n *NetLink) AddrReplace(Link, Addr) error {
-	panic("not implemented")
-}

internal/netlink/family.go

@@ -4,12 +4,6 @@ import (
 	"fmt"
 )
 
-const (
-	FamilyAll = 0
-	FamilyV4  = 2
-	FamilyV6  = 10
-)
-
 func FamilyToString(family int) string {
 	switch family {
 	case FamilyAll:

internal/netlink/family_linux.go

@@ -0,0 +1,9 @@
+package netlink
+
+import "golang.org/x/sys/unix"
+
+const (
+	FamilyAll = unix.AF_UNSPEC
+	FamilyV4  = unix.AF_INET
+	FamilyV6  = unix.AF_INET6
+)

internal/netlink/link.go

@@ -1,5 +1,3 @@
-//go:build linux || darwin
-
 package netlink
 
 import "github.com/vishvananda/netlink"
@@ -62,8 +60,8 @@ func (n *NetLink) LinkSetDown(link Link) (err error) {
 	return netlink.LinkSetDown(linkToNetlinkLink(&link))
 }
 
-func (n *NetLink) LinkSetMTU(link Link, mtu int) error {
-	return netlink.LinkSetMTU(linkToNetlinkLink(&link), mtu)
+func (n *NetLink) LinkSetMTU(link Link, mtu uint32) error {
+	return netlink.LinkSetMTU(linkToNetlinkLink(&link), int(mtu))
 }
 
 type netlinkLinkImpl struct {

internal/netlink/link_unspecified.go

@@ -1,31 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) LinkList() (links []Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByName(name string) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByIndex(index int) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkAdd(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkDel(link Link) (err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetUp(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetDown(link Link) (err error) {
-	panic("not implemented")
-}

internal/netlink/netlink_unspecified.go

@@ -0,0 +1,31 @@
+//go:build !linux
+
+package netlink
+
+const (
+	// FamilyAll is a placeholder only and should not
+	// be used.
+	FamilyAll = iota
+	// FamilyV4 is a placeholder only and should not
+	// be used.
+	FamilyV4
+	// FamilyV6 is a placeholder only and should not
+	// be used.
+	FamilyV6
+)
+
+func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
+	panic("not implemented")
+}
+
+func (n *NetLink) RuleAdd(rule Rule) error {
+	panic("not implemented")
+}
+
+func (n *NetLink) RuleDel(rule Rule) error {
+	panic("not implemented")
+}
+
+func (n *NetLink) IsWireguardSupported() bool {
+	panic("not implemented")
+}

internal/netlink/route.go

@@ -1,5 +1,3 @@
-//go:build linux || darwin
-
 package netlink
 
 import (

internal/netlink/route_unspecified.go

@@ -1,21 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) RouteList(family int) (
-	routes []Route, err error,
-) {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteAdd(route Route) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteDel(route Route) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteReplace(route Route) error {
-	panic("not implemented")
-}

internal/netlink/rule.go

@@ -1,5 +1,3 @@
-//go:build linux
-
 package netlink
 
 import (
@@ -18,40 +16,6 @@ func NewRule() Rule {
 	}
 }
 
-func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
-	switch family {
-	case FamilyAll:
-		n.debugLogger.Debug("ip -4 rule list")
-		n.debugLogger.Debug("ip -6 rule list")
-	case FamilyV4:
-		n.debugLogger.Debug("ip -4 rule list")
-	case FamilyV6:
-		n.debugLogger.Debug("ip -6 rule list")
-	}
-	netlinkRules, err := netlink.RuleList(family)
-	if err != nil {
-		return nil, err
-	}
-
-	rules = make([]Rule, len(netlinkRules))
-	for i := range netlinkRules {
-		rules[i] = netlinkRuleToRule(netlinkRules[i])
-	}
-	return rules, nil
-}
-
-func (n *NetLink) RuleAdd(rule Rule) error {
-	n.debugLogger.Debug(ruleDbgMsg(true, rule))
-	netlinkRule := ruleToNetlinkRule(rule)
-	return netlink.RuleAdd(&netlinkRule)
-}
-
-func (n *NetLink) RuleDel(rule Rule) error {
-	n.debugLogger.Debug(ruleDbgMsg(false, rule))
-	netlinkRule := ruleToNetlinkRule(rule)
-	return netlink.RuleDel(&netlinkRule)
-}
-
 func ruleToNetlinkRule(rule Rule) (netlinkRule netlink.Rule) {
 	netlinkRule = *netlink.NewRule()
 	netlinkRule.Priority = rule.Priority

internal/netlink/rule_linux.go

@@ -0,0 +1,37 @@
+package netlink
+
+import "github.com/vishvananda/netlink"
+
+func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
+	switch family {
+	case FamilyAll:
+		n.debugLogger.Debug("ip -4 rule list")
+		n.debugLogger.Debug("ip -6 rule list")
+	case FamilyV4:
+		n.debugLogger.Debug("ip -4 rule list")
+	case FamilyV6:
+		n.debugLogger.Debug("ip -6 rule list")
+	}
+	netlinkRules, err := netlink.RuleList(family)
+	if err != nil {
+		return nil, err
+	}
+
+	rules = make([]Rule, len(netlinkRules))
+	for i := range netlinkRules {
+		rules[i] = netlinkRuleToRule(netlinkRules[i])
+	}
+	return rules, nil
+}
+
+func (n *NetLink) RuleAdd(rule Rule) error {
+	n.debugLogger.Debug(ruleDbgMsg(true, rule))
+	netlinkRule := ruleToNetlinkRule(rule)
+	return netlink.RuleAdd(&netlinkRule)
+}
+
+func (n *NetLink) RuleDel(rule Rule) error {
+	n.debugLogger.Debug(ruleDbgMsg(false, rule))
+	netlinkRule := ruleToNetlinkRule(rule)
+	return netlink.RuleDel(&netlinkRule)
+}

internal/netlink/rule_unspecified.go

@@ -1,19 +0,0 @@
-//go:build !linux
-
-package netlink
-
-func NewRule() Rule {
-	return Rule{}
-}
-
-func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) RuleAdd(rule Rule) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RuleDel(rule Rule) error {
-	panic("not implemented")
-}

internal/netlink/wireguard_linux.go

@@ -1,5 +1,3 @@
-//go:build linux
-
 package netlink
 
 import (

internal/netlink/wireguard_unspecified.go

@@ -1,7 +0,0 @@
-//go:build !linux
-
-package netlink
-
-func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
-	panic("not implemented")
-}

internal/openvpn/start.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"os/exec"
-	"syscall"
 
 	"github.com/qdm12/gluetun/internal/constants/openvpn"
 )
@@ -33,7 +32,7 @@ func start(ctx context.Context, starter CmdStarter, version string, flags []stri
 	args := []string{"--config", configPath}
 	args = append(args, flags...)
 	cmd := exec.CommandContext(ctx, bin, args...)
-	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	setCmdSysProcAttr(cmd)
 
 	return starter.Start(cmd)
 }

internal/openvpn/start_linux.go

@@ -0,0 +1,10 @@
+package openvpn
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func setCmdSysProcAttr(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+}

internal/openvpn/start_unspecified.go

@@ -0,0 +1,12 @@
+//go:build !linux
+
+package openvpn
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func setCmdSysProcAttr(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{}
+}

internal/pmtud/check.go

@@ -13,7 +13,7 @@ var (
 	ErrICMPNextHopMTUTooHigh = errors.New("ICMP Next Hop MTU is too high")
 )
 
-func checkMTU(mtu, minMTU, physicalLinkMTU int) (err error) {
+func checkMTU(mtu, minMTU, physicalLinkMTU uint32) (err error) {
 	switch {
 	case mtu < minMTU:
 		return fmt.Errorf("%w: %d", ErrICMPNextHopMTUTooLow, mtu)

internal/pmtud/df_linux.go

@@ -1,5 +1,3 @@
-//go:build linux
-
 package pmtud
 
 import (

internal/pmtud/ipv4.go

@@ -17,8 +17,8 @@ import (
 
 const (
 	// see https://en.wikipedia.org/wiki/Maximum_transmission_unit#MTUs_for_common_media
-	minIPv4MTU     = 68
-	icmpv4Protocol = 1
+	minIPv4MTU     uint32 = 68
+	icmpv4Protocol int    = 1
 )
 
 func listenICMPv4(ctx context.Context) (conn net.PacketConn, err error) {
@@ -51,8 +51,8 @@ func listenICMPv4(ctx context.Context) (conn net.PacketConn, err error) {
 }
 
 func findIPv4NextHopMTU(ctx context.Context, ip netip.Addr,
-	physicalLinkMTU int, pingTimeout time.Duration, logger Logger,
-) (mtu int, err error) {
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger,
+) (mtu uint32, err error) {
 	if ip.Is6() {
 		panic("IP address is not v4")
 	}
@@ -124,7 +124,7 @@ func findIPv4NextHopMTU(ctx context.Context, ip netip.Addr,
 			// See https://datatracker.ietf.org/doc/html/rfc1191#section-4
 			// Note: the go library does not handle this NextHopMTU section.
 			nextHopMTU := packetBytes[6:8]
-			mtu = int(binary.BigEndian.Uint16(nextHopMTU))
+			mtu = uint32(binary.BigEndian.Uint16(nextHopMTU))
 			err = checkMTU(mtu, minIPv4MTU, physicalLinkMTU)
 			if err != nil {
 				return 0, fmt.Errorf("checking next-hop-mtu found: %w", err)

internal/pmtud/ipv6.go

@@ -31,8 +31,8 @@ func listenICMPv6(ctx context.Context) (conn net.PacketConn, err error) {
 }
 
 func getIPv6PacketTooBig(ctx context.Context, ip netip.Addr,
-	physicalLinkMTU int, pingTimeout time.Duration, logger Logger,
-) (mtu int, err error) {
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger,
+) (mtu uint32, err error) {
 	if ip.Is4() {
 		panic("IP address is not v6")
 	}
@@ -84,7 +84,7 @@ func getIPv6PacketTooBig(ctx context.Context, ip netip.Addr,
 		switch typedBody := inboundMessage.Body.(type) {
 		case *icmp.PacketTooBig:
 			// https://datatracker.ietf.org/doc/html/rfc1885#section-3.2
-			mtu = typedBody.MTU
+			mtu = uint32(typedBody.MTU) //nolint:gosec
 			err = checkMTU(mtu, minIPv6MTU, physicalLinkMTU)
 			if err != nil {
 				return 0, fmt.Errorf("checking MTU: %w", err)
@@ -96,7 +96,7 @@ func getIPv6PacketTooBig(ctx context.Context, ip netip.Addr,
 			if err != nil {
 				return 0, fmt.Errorf("checking invoking message: %w", err)
 			}
-			return typedBody.MTU, nil
+			return uint32(typedBody.MTU), nil //nolint:gosec
 		case *icmp.DstUnreach:
 			// https://datatracker.ietf.org/doc/html/rfc1885#section-3.1
 			idMatch, err := checkInvokingReplyIDMatch(icmpv6Protocol, packetBytes, outboundMessage)

internal/pmtud/message.go

@@ -11,7 +11,7 @@ import (
 	"golang.org/x/net/ipv6"
 )
 
-func buildMessageToSend(ipVersion string, mtu int) (id uint16, message *icmp.Message) {
+func buildMessageToSend(ipVersion string, mtu uint32) (id uint16, message *icmp.Message) {
 	var seed [32]byte
 	_, _ = cryptorand.Read(seed[:])
 	randomSource := rand.NewChaCha8(seed)
@@ -21,7 +21,7 @@ func buildMessageToSend(ipVersion string, mtu int) (id uint16, message *icmp.Mes
 	_, _ = randomSource.Read(idBytes)
 	id = binary.BigEndian.Uint16(idBytes)
 
-	var ipHeaderLength int
+	var ipHeaderLength uint32
 	var icmpType icmp.Type
 	switch ipVersion {
 	case "v4":

internal/pmtud/pmtud.go

@@ -21,8 +21,8 @@ var ErrMTUNotFound = errors.New("path MTU discovery failed to find MTU")
 // If the logger is nil, a no-op logger is used.
 // It returns [ErrMTUNotFound] if the MTU could not be determined.
 func PathMTUDiscover(ctx context.Context, ip netip.Addr,
-	physicalLinkMTU int, pingTimeout time.Duration, logger Logger) (
-	mtu int, err error,
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger) (
+	mtu uint32, err error,
 ) {
 	if physicalLinkMTU == 0 {
 		const ethernetStandardMTU = 1500
@@ -68,16 +68,16 @@ func PathMTUDiscover(ctx context.Context, ip netip.Addr,
 }
 
 type pmtudTestUnit struct {
-	mtu       int
+	mtu       uint32
 	echoID    uint16
 	sentBytes int
 	ok        bool
 }
 
 func pmtudMultiSizes(ctx context.Context, ip netip.Addr,
-	minMTU, maxPossibleMTU int, pingTimeout time.Duration,
+	minMTU, maxPossibleMTU uint32, pingTimeout time.Duration,
 	logger Logger,
-) (maxMTU int, err error) {
+) (maxMTU uint32, err error) {
 	var ipVersion string
 	var conn net.PacketConn
 	if ip.Is4() {
@@ -164,22 +164,22 @@ func pmtudMultiSizes(ctx context.Context, ip netip.Addr,
 // with a total search space of 1728 MTUs which is enough;
 // to find it in 2 searches requires 37 parallel queries which
 // could be blocked by firewalls.
-func makeMTUsToTest(minMTU, maxMTU int) (mtus []int) {
+func makeMTUsToTest(minMTU, maxMTU uint32) (mtus []uint32) {
 	const mtusLength = 11 // find the final MTU in 3 searches
 	diff := maxMTU - minMTU
 	switch {
 	case minMTU > maxMTU:
 		panic("minMTU > maxMTU")
 	case diff <= mtusLength:
-		mtus = make([]int, 0, diff)
+		mtus = make([]uint32, 0, diff)
 		for mtu := minMTU; mtu <= maxMTU; mtu++ {
 			mtus = append(mtus, mtu)
 		}
 	default:
 		step := float64(diff) / float64(mtusLength-1)
-		mtus = make([]int, 0, mtusLength)
+		mtus = make([]uint32, 0, mtusLength)
 		for mtu := float64(minMTU); len(mtus) < mtusLength-1; mtu += step {
-			mtus = append(mtus, int(math.Round(mtu)))
+			mtus = append(mtus, uint32(math.Round(mtu)))
 		}
 		mtus = append(mtus, maxMTU) // last element is the maxMTU
 	}

internal/pmtud/pmtud_test.go

@@ -10,37 +10,37 @@ func Test_makeMTUsToTest(t *testing.T) {
 	t.Parallel()
 
 	testCases := map[string]struct {
-		minMTU int
-		maxMTU int
-		mtus   []int
+		minMTU uint32
+		maxMTU uint32
+		mtus   []uint32
 	}{
 		"0_0": {
-			mtus: []int{0},
+			mtus: []uint32{0},
 		},
 		"0_1": {
 			maxMTU: 1,
-			mtus:   []int{0, 1},
+			mtus:   []uint32{0, 1},
 		},
 		"0_8": {
 			maxMTU: 8,
-			mtus:   []int{0, 1, 2, 3, 4, 5, 6, 7, 8},
+			mtus:   []uint32{0, 1, 2, 3, 4, 5, 6, 7, 8},
 		},
 		"0_12": {
 			maxMTU: 12,
-			mtus:   []int{0, 1, 2, 4, 5, 6, 7, 8, 10, 11, 12},
+			mtus:   []uint32{0, 1, 2, 4, 5, 6, 7, 8, 10, 11, 12},
 		},
 		"0_80": {
 			maxMTU: 80,
-			mtus:   []int{0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80},
+			mtus:   []uint32{0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80},
 		},
 		"0_100": {
 			maxMTU: 100,
-			mtus:   []int{0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100},
+			mtus:   []uint32{0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100},
 		},
 		"1280_1500": {
 			minMTU: 1280,
 			maxMTU: 1500,
-			mtus:   []int{1280, 1302, 1324, 1346, 1368, 1390, 1412, 1434, 1456, 1478, 1500},
+			mtus:   []uint32{1280, 1302, 1324, 1346, 1368, 1390, 1412, 1434, 1456, 1478, 1500},
 		},
 	}
 

internal/routing/default.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var ErrRouteDefaultNotFound = errors.New("default route not found")
@@ -30,7 +29,7 @@ func (r *Routing) DefaultRoutes() (defaultRoutes []DefaultRoute, err error) {
 	}
 
 	for _, route := range routes {
-		if route.Table != unix.RT_TABLE_MAIN {
+		if route.Table != tableMain {
 			// ignore non-main table
 			continue
 		}

internal/routing/local.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var (
@@ -48,7 +47,7 @@ func (r *Routing) LocalNetworks() (localNetworks []LocalNetwork, err error) {
 	}
 
 	for _, route := range routes {
-		if route.Table != unix.RT_TABLE_MAIN ||
+		if route.Table != tableMain ||
 			(route.Gw.IsValid() && !route.Gw.IsUnspecified()) ||
 			(route.Dst.IsValid() && route.Dst.Addr().IsUnspecified()) {
 			continue

internal/routing/tables_linux.go

@@ -0,0 +1,8 @@
+package routing
+
+import "golang.org/x/sys/unix"
+
+const (
+	tableMain  = unix.RT_TABLE_MAIN
+	tableLocal = unix.RT_TABLE_LOCAL
+)

internal/routing/tables_unspecified.go

@@ -0,0 +1,8 @@
+//go:build !linux
+
+package routing
+
+const (
+	tableMain  = 0
+	tableLocal = 0
+)

internal/routing/vpn.go

@@ -6,7 +6,6 @@ import (
 	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 )
 
 var (
@@ -35,7 +34,7 @@ func (r *Routing) VPNLocalGatewayIP(vpnIntf string) (ip netip.Addr, err error) {
 			return route.Gw, nil
 		case route.Dst.IsSingleIP() &&
 			route.Dst.Addr().Compare(route.Src) == 0 &&
-			route.Table == unix.RT_TABLE_LOCAL: // Wireguard
+			route.Table == tableLocal: // Wireguard
 			route.Src = route.Src.Unmap()
 			if route.Src.Is6() {
 				return netip.Addr{}, fmt.Errorf("%w: %s", ErrVPNLocalGatewayIPv6NotSupported, route.Src)

internal/vpn/interfaces.go

@@ -81,7 +81,7 @@ type Linker interface {
 	LinkDel(link netlink.Link) (err error)
 	LinkSetUp(link netlink.Link) (linkIndex int, err error)
 	LinkSetDown(link netlink.Link) (err error)
-	LinkSetMTU(link netlink.Link, mtu int) (err error)
+	LinkSetMTU(link netlink.Link, mtu uint32) (err error)
 }
 
 type DNSLoop interface {

internal/vpn/tunnelup.go

@@ -157,7 +157,7 @@ func updateToMaxMTU(ctx context.Context, vpnInterface string,
 
 	// Note: no point testing for an MTU of 1500, it will never work due to the VPN
 	// protocol overhead, so start lower than 1500 according to the protocol used.
-	const physicalLinkMTU = 1500
+	const physicalLinkMTU uint32 = 1500
 	vpnLinkMTU := physicalLinkMTU
 	switch vpnType {
 	case "wireguard":
@@ -183,7 +183,7 @@ func updateToMaxMTU(ctx context.Context, vpnInterface string,
 	case err == nil:
 		logger.Infof("setting VPN interface %s MTU to maximum valid MTU %d", vpnInterface, vpnLinkMTU)
 	case errors.Is(err, pmtud.ErrMTUNotFound) || errors.Is(err, pmtud.ErrICMPNotPermitted):
-		vpnLinkMTU = int(originalMTU)
+		vpnLinkMTU = uint32(originalMTU)
 		logger.Infof("reverting VPN interface %s MTU to %d (due to: %s)",
 			vpnInterface, originalMTU, err)
 	default:

internal/wireguard/run.go

@@ -7,10 +7,8 @@ import (
 	"net"
 
 	"github.com/qdm12/gluetun/internal/netlink"
-	"golang.org/x/sys/unix"
 	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/device"
-	"golang.zx2c4.com/wireguard/ipc"
 	"golang.zx2c4.com/wireguard/tun"
 	"golang.zx2c4.com/wireguard/wgctrl"
 )
@@ -106,7 +104,7 @@ func (w *Wireguard) Run(ctx context.Context, waitError chan<- error, ready chan<
 	if *w.settings.IPv6 {
 		// requires net.ipv6.conf.all.disable_ipv6=0
 		ruleCleanup6, err := w.addRule(w.settings.RulePriority,
-			w.settings.FirewallMark, unix.AF_INET6)
+			w.settings.FirewallMark, netlink.FamilyV6)
 		if err != nil {
 			waitError <- fmt.Errorf("adding IPv6 rule: %w", err)
 			return
@@ -115,7 +113,7 @@ func (w *Wireguard) Run(ctx context.Context, waitError chan<- error, ready chan<
 	}
 
 	ruleCleanup, err := w.addRule(w.settings.RulePriority,
-		w.settings.FirewallMark, unix.AF_INET)
+		w.settings.FirewallMark, netlink.FamilyV4)
 	if err != nil {
 		waitError <- fmt.Errorf("adding IPv4 rule: %w", err)
 		return
@@ -217,14 +215,14 @@ func setupUserSpace(ctx context.Context,
 		return nil
 	})
 
-	uapiFile, err := ipc.UAPIOpen(interfaceName)
+	uapiFile, err := uapiOpen(interfaceName)
 	if err != nil {
 		return link, nil, fmt.Errorf("%w: %s", ErrUAPISocketOpening, err)
 	}
 
 	closers.add("closing UAPI file", stepThree, uapiFile.Close)
 
-	uapiListener, err := ipc.UAPIListen(interfaceName, uapiFile)
+	uapiListener, err := uapiListen(interfaceName, uapiFile)
 	if err != nil {
 		return link, nil, fmt.Errorf("%w: %s", ErrUAPIListen, err)
 	}

internal/wireguard/wireguard_linux.go

@@ -0,0 +1,16 @@
+package wireguard
+
+import (
+	"net"
+	"os"
+
+	"golang.zx2c4.com/wireguard/ipc"
+)
+
+func uapiOpen(name string) (*os.File, error) {
+	return ipc.UAPIOpen(name)
+}
+
+func uapiListen(interfaceName string, uapiFile *os.File) (net.Listener, error) {
+	return ipc.UAPIListen(interfaceName, uapiFile)
+}

internal/wireguard/wireguard_unspecified.go

@@ -0,0 +1,16 @@
+//go:build !linux
+
+package wireguard
+
+import (
+	"net"
+	"os"
+)
+
+func uapiOpen(name string) (*os.File, error) {
+	panic("not implemented")
+}
+
+func uapiListen(interfaceName string, uapiFile *os.File) (net.Listener, error) {
+	panic("not implemented")
+}