Rename tuntap package to tun

We haven't had TAP support in ages.

src/tun/tun_darwin.go

@@ -0,0 +1,133 @@
+//go:build !mobile
+// +build !mobile
+
+package tun
+
+// The darwin platform specific tun parts
+
+import (
+	"encoding/binary"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+
+	wgtun "golang.zx2c4.com/wireguard/tun"
+)
+
+// Configures the "utun" adapter with the correct IPv6 address and MTU.
+func (tun *TunAdapter) setup(ifname string, addr string, mtu uint64) error {
+	if ifname == "auto" {
+		ifname = "utun"
+	}
+	iface, err := wgtun.CreateTUN(ifname, int(mtu))
+	if err != nil {
+		panic(err)
+	}
+	tun.iface = iface
+	if m, err := iface.MTU(); err == nil {
+		tun.mtu = getSupportedMTU(uint64(m))
+	} else {
+		tun.mtu = 0
+	}
+	return tun.setupAddress(addr)
+}
+
+const (
+	darwin_SIOCAIFADDR_IN6       = 2155899162 // netinet6/in6_var.h
+	darwin_IN6_IFF_NODAD         = 0x0020     // netinet6/in6_var.h
+	darwin_IN6_IFF_SECURED       = 0x0400     // netinet6/in6_var.h
+	darwin_ND6_INFINITE_LIFETIME = 0xFFFFFFFF // netinet6/nd6.h
+)
+
+// nolint:structcheck
+type in6_addrlifetime struct {
+	ia6t_expire    float64 // nolint:unused
+	ia6t_preferred float64 // nolint:unused
+	ia6t_vltime    uint32
+	ia6t_pltime    uint32
+}
+
+// nolint:structcheck
+type sockaddr_in6 struct {
+	sin6_len      uint8
+	sin6_family   uint8
+	sin6_port     uint8  // nolint:unused
+	sin6_flowinfo uint32 // nolint:unused
+	sin6_addr     [8]uint16
+	sin6_scope_id uint32 // nolint:unused
+}
+
+// nolint:structcheck
+type in6_aliasreq struct {
+	ifra_name       [16]byte
+	ifra_addr       sockaddr_in6
+	ifra_dstaddr    sockaddr_in6 // nolint:unused
+	ifra_prefixmask sockaddr_in6
+	ifra_flags      uint32
+	ifra_lifetime   in6_addrlifetime
+}
+
+type ifreq struct {
+	ifr_name [16]byte
+	ifru_mtu uint32
+}
+
+// Sets the IPv6 address of the utun adapter. On Darwin/macOS this is done using
+// a system socket and making direct syscalls to the kernel.
+func (tun *TunAdapter) setupAddress(addr string) error {
+	var fd int
+	var err error
+
+	if fd, err = unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, 0); err != nil {
+		tun.log.Printf("Create AF_SYSTEM socket failed: %v.", err)
+		return err
+	}
+
+	var ar in6_aliasreq
+	copy(ar.ifra_name[:], tun.Name())
+
+	ar.ifra_prefixmask.sin6_len = uint8(unsafe.Sizeof(ar.ifra_prefixmask))
+	b := make([]byte, 16)
+	binary.LittleEndian.PutUint16(b, uint16(0xFE00))
+	ar.ifra_prefixmask.sin6_addr[0] = binary.BigEndian.Uint16(b)
+
+	ar.ifra_addr.sin6_len = uint8(unsafe.Sizeof(ar.ifra_addr))
+	ar.ifra_addr.sin6_family = unix.AF_INET6
+	parts := strings.Split(strings.Split(addr, "/")[0], ":")
+	for i := 0; i < 8; i++ {
+		addr, _ := strconv.ParseUint(parts[i], 16, 16)
+		b := make([]byte, 16)
+		binary.LittleEndian.PutUint16(b, uint16(addr))
+		ar.ifra_addr.sin6_addr[i] = binary.BigEndian.Uint16(b)
+	}
+
+	ar.ifra_flags |= darwin_IN6_IFF_NODAD
+	ar.ifra_flags |= darwin_IN6_IFF_SECURED
+
+	ar.ifra_lifetime.ia6t_vltime = darwin_ND6_INFINITE_LIFETIME
+	ar.ifra_lifetime.ia6t_pltime = darwin_ND6_INFINITE_LIFETIME
+
+	var ir ifreq
+	copy(ir.ifr_name[:], tun.Name())
+	ir.ifru_mtu = uint32(tun.mtu)
+
+	tun.log.Infof("Interface name: %s", ar.ifra_name)
+	tun.log.Infof("Interface IPv6: %s", addr)
+	tun.log.Infof("Interface MTU: %d", ir.ifru_mtu)
+
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), uintptr(darwin_SIOCAIFADDR_IN6), uintptr(unsafe.Pointer(&ar))); errno != 0 {
+		err = errno
+		tun.log.Errorf("Error in darwin_SIOCAIFADDR_IN6: %v", errno)
+		return err
+	}
+
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), uintptr(unix.SIOCSIFMTU), uintptr(unsafe.Pointer(&ir))); errno != 0 {
+		err = errno
+		tun.log.Errorf("Error in SIOCSIFMTU: %v", errno)
+		return err
+	}
+
+	return err
+}