From c3600d14d666743e7082178addba57c9f82f5874 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 5 Jan 2018 23:35:59 +0000
Subject: [PATCH 1/2] Implement a tun interface to reduce dependency on Water
 library

---
 src/yggdrasil/tun.go | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/yggdrasil/tun.go b/src/yggdrasil/tun.go
index 7c4a06ea..3a819982 100644
--- a/src/yggdrasil/tun.go
+++ b/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) {

From d69190715f50befa2d15ee016e71563fc937952b Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Sat, 6 Jan 2018 16:39:30 +0000
Subject: [PATCH 2/2] Added a darwin tun module. It should work, but it
 doesn't!

---
 src/yggdrasil/tun_darwin.go | 105 ++++++++++++++++++++++++++++++++++++
 src/yggdrasil/tun_other.go  |   1 +
 2 files changed, 106 insertions(+)
 create mode 100644 src/yggdrasil/tun_darwin.go

diff --git a/src/yggdrasil/tun_darwin.go b/src/yggdrasil/tun_darwin.go
new file mode 100644
index 00000000..7562a909
--- /dev/null
+++ b/src/yggdrasil/tun_darwin.go
@@ -0,0 +1,105 @@
+package yggdrasil
+
+// The darwin platform specific tun parts
+
+import "syscall"
+import "unsafe"
+import "strings"
+import "strconv"
+import "encoding/binary"
+
+import water "github.com/songgao/water"
+
+func (tun *tunDevice) setup(ifname string, addr string, mtu int) error {
+	config := water.Config{DeviceType: water.TUN}
+	iface, err := water.New(config)
+	if err != nil {
+		panic(err)
+	}
+	tun.iface = iface
+	tun.mtu = mtu
+	return tun.setupAddress(addr)
+}
+
+const AF_INET6 = 30
+const IN6_IFF_NODAD = 0x0020
+const SIOCAIFADDR_IN6 = (0x80000000) | ((4 & 0x1fff) << 16) | uint32(byte('i'))<<8 | 26
+
+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
+}
+
+func (tun *tunDevice) setupAddress(addr string) error {
+	var fd int
+	var err error
+
+	if fd, err = syscall.Socket(syscall.AF_INET6, syscall.SOCK_DGRAM, 0); err != nil {
+		tun.core.log.Printf("Create AF_SYSTEM socket failed: %v.", err)
+		return err
+	}
+
+	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 = 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
+
+	tun.core.log.Printf("Interface name: %s", ar.ifra_name)
+	tun.core.log.Printf("Interface IPv6: %s", addr)
+
+	/*
+		var bytes *[unsafe.Sizeof(ar)]byte = (*[unsafe.Sizeof(ar)]byte)(unsafe.Pointer(&ar));
+		var out string;
+		for i := 0; i < int(unsafe.Sizeof(ar)); i ++ {
+			out += fmt.Sprintf("0x%02x", (*bytes)[i]);
+			if i % 8 == 7 {
+				out += "\n"
+			} else {
+				out += " "
+			}
+		}
+		tun.core.log.Printf("in6_aliasreq:\n%s", out);
+  */
+
+	if _, _, errno := syscall.Syscall(syscall.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 err
+}
diff --git a/src/yggdrasil/tun_other.go b/src/yggdrasil/tun_other.go
index 92be426d..e525827c 100644
--- a/src/yggdrasil/tun_other.go
+++ b/src/yggdrasil/tun_other.go
@@ -1,4 +1,5 @@
 // +build !linux
+// +build !darwin
 
 package yggdrasil