Fix missing setupFD stubs

src/tun/tun_bsd.go

@@ -5,6 +5,7 @@ package tun
 
 import (
 	"encoding/binary"
+	"fmt"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -88,6 +89,11 @@ func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
 	return tun.setupAddress(addr)
 }
 
+// Configures the "utun" adapter from an existing file descriptor.
+func (tun *TunAdapter) setupFD(fd int32, addr string, mtu uint64) error {
+	return fmt.Errorf("setup via FD not supported on this platform")
+}
+
 func (tun *TunAdapter) setupAddress(addr string) error {
 	var sfd int
 	var err error

src/tun/tun_linux.go

@@ -6,6 +6,8 @@ package tun
 // The linux platform specific tun parts
 
 import (
+	"fmt"
+
 	"github.com/vishvananda/netlink"
 	wgtun "golang.zx2c4.com/wireguard/tun"
 )
@@ -28,6 +30,11 @@ func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
 	return tun.setupAddress(addr)
 }
 
+// Configures the "utun" adapter from an existing file descriptor.
+func (tun *TunAdapter) setupFD(fd int32, addr string, mtu uint64) error {
+	return fmt.Errorf("setup via FD not supported on this platform")
+}
+
 // Configures the TUN adapter with the correct IPv6 address and MTU. Netlink
 // is used to do this, so there is not a hard requirement on "ip" or "ifconfig"
 // to exist on the system, but this will fail if Netlink is not present in the

src/tun/tun_other.go

@@ -7,6 +7,8 @@ package tun
 // If your platform supports tun devices, you could try configuring it manually
 
 import (
+	"fmt"
+
 	wgtun "golang.zx2c4.com/wireguard/tun"
 )
 
@@ -25,6 +27,11 @@ func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
 	return tun.setupAddress(addr)
 }
 
+// Configures the "utun" adapter from an existing file descriptor.
+func (tun *TunAdapter) setupFD(fd int32, addr string, mtu uint64) error {
+	return fmt.Errorf("setup via FD not supported on this platform")
+}
+
 // We don't know how to set the IPv6 address on an unknown platform, therefore
 // write about it to stdout and don't try to do anything further.
 func (tun *TunAdapter) setupAddress(addr string) error {

src/tun/tun_windows.go

@@ -6,6 +6,7 @@ package tun
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"log"
 	"net"
 
@@ -50,6 +51,11 @@ func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
 	})
 }
 
+// Configures the "utun" adapter from an existing file descriptor.
+func (tun *TunAdapter) setupFD(fd int32, addr string, mtu uint64) error {
+	return fmt.Errorf("setup via FD not supported on this platform")
+}
+
 // Sets the MTU of the TUN adapter.
 func (tun *TunAdapter) setupMTU(mtu uint64) error {
 	if tun.iface == nil || tun.Name() == "" {