Merge pull request #3 from neilalexander/master

Update tun_darwin.go with working interface code using syscalls

src/yggdrasil/tun.go

@@ -2,16 +2,25 @@ package yggdrasil
 
 // This manages the tun driver to send/recv packets to/from applications
 
-import water "github.com/songgao/water"
+// import water "github.com/songgao/water"
 
 const IPv6_HEADER_LENGTH = 40
 
+type tunInterface interface {
+	IsTUN() bool
+	IsTAP() bool
+	Name() string
+	Read(to []byte) (int, error)
+	Write(from []byte) (int, error)
+	Close() error
+}
+
 type tunDevice struct {
 	core  *Core
 	send  chan<- []byte
 	recv  <-chan []byte
 	mtu   int
-	iface *water.Interface
+	iface tunInterface
 }
 
 func (tun *tunDevice) init(core *Core) {

src/yggdrasil/tun_darwin.go

@@ -1,14 +1,12 @@
 package yggdrasil
 
 // The darwin platform specific tun parts
-// macOS/Darwin is BSD-derived and doesn't have iproute2. This code instead
-// uses ifconfig. There is actually code that tries to do this properly using
-// syscalls in github.com/neilalexander/yggdrasil-go branch "macos-interface"
-// but for some reason it doesn't work as expected!
 
-import "fmt"
-import "os/exec"
+import "unsafe"
 import "strings"
+import "strconv"
+import "encoding/binary"
+import "golang.org/x/sys/unix"
 
 import water "github.com/songgao/water"
 
@@ -19,30 +17,89 @@ func (tun *tunDevice) setup(ifname string, addr string, mtu int) error {
 		panic(err)
 	}
 	tun.iface = iface
-	tun.mtu = mtu //1280 // Lets default to the smallest thing allowed for now
+	tun.mtu = mtu
 	return tun.setupAddress(addr)
 }
 
+const SIOCAIFADDR_IN6 = 2155899162
+
+type in6_addrlifetime struct {
+	ia6t_expire    float64
+	ia6t_preferred float64
+	ia6t_vltime    uint32
+	ia6t_pltime    uint32
+}
+
+type sockaddr_in6 struct {
+	sin6_len      uint8
+	sin6_family   uint8
+	sin6_port     uint8
+	sin6_flowinfo uint32
+	sin6_addr     [8]uint16
+	sin6_scope_id uint32
+}
+
+type in6_aliasreq struct {
+	ifra_name       [16]byte
+	ifra_addr       sockaddr_in6
+	ifra_dstaddr    sockaddr_in6
+	ifra_prefixmask sockaddr_in6
+	ifra_flags			uint32
+	ifra_lifetime   in6_addrlifetime
+}
+
+type ifreq struct {
+	ifr_name				[16]byte
+	ifru_mtu				uint32
+}
+
 func (tun *tunDevice) setupAddress(addr string) error {
-	// Set address
-	cmd := exec.Command("ifconfig", tun.iface.Name(), "inet6",
-		"add", addr)
-	tun.core.log.Printf("ifconfig command: %v", strings.Join(cmd.Args, " "))
-	output, err := cmd.CombinedOutput()
-	if err != nil {
-		tun.core.log.Printf("Darwin ifconfig failed: %v.", err)
-		tun.core.log.Println(string(output))
+	var fd int
+	var err error
+
+	if fd, err = unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, 0); err != nil {
+		tun.core.log.Printf("Create AF_SYSTEM socket failed: %v.", err)
 		return err
 	}
-	// Set MTU and bring device up
-	cmd = exec.Command("ifconfig", tun.iface.Name(), "mtu",
-		fmt.Sprintf("%d", tun.mtu))
-	tun.core.log.Printf("ifconfig command: %v", strings.Join(cmd.Args, " "))
-	output, err = cmd.CombinedOutput()
-	if err != nil {
-		tun.core.log.Printf("Darwin ifconfig failed: %v.", err)
-		tun.core.log.Println(string(output))
+
+	var ar in6_aliasreq
+	copy(ar.ifra_name[:], tun.iface.Name())
+
+	ar.ifra_prefixmask.sin6_len = uint8(unsafe.Sizeof(ar.ifra_prefixmask))
+	b := make([]byte, 16); binary.LittleEndian.PutUint16(b, uint16(0xFF00))
+	ar.ifra_prefixmask.sin6_addr[0] = uint16(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.TrimRight(addr, "/8"), ":")
+	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] = uint16(binary.BigEndian.Uint16(b))
+	}
+
+	ar.ifra_lifetime.ia6t_vltime = 0xFFFFFFFF
+	ar.ifra_lifetime.ia6t_pltime = 0xFFFFFFFF
+
+	var ir ifreq
+	copy(ir.ifr_name[:], tun.iface.Name())
+	ir.ifru_mtu = uint32(tun.mtu)
+
+	tun.core.log.Printf("Interface name: %s", ar.ifra_name)
+	tun.core.log.Printf("Interface IPv6: %s", addr)
+	tun.core.log.Printf("Interface MTU: %d", ir.ifru_mtu)
+
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), uintptr(SIOCAIFADDR_IN6), uintptr(unsafe.Pointer(&ar))); errno != 0 {
+		err = errno
+		tun.core.log.Printf("Error in SIOCAIFADDR_IN6: %v", errno)
 		return err
 	}
-	return nil
+
+	if _, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(fd), uintptr(unix.SIOCSIFMTU), uintptr(unsafe.Pointer(&ir))); errno != 0 {
+		err = errno
+		tun.core.log.Printf("Error in SIOCSIFMTU: %v", errno)
+		return err
+	}
+
+	return err
 }