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yggdrasil-go/src/tuntap/tun_darwin.go

133 lines
3.4 KiB
Go

// +build !mobile
package tuntap
// 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
}