[PATCH 6/7] tun_darwin: adapt to TUNDevice interface change

[Simon Ruderich <simon@ruderich.org>]

Broken in 996c7c4 ("Removed IFF_NO_PI from TUN linux", 2017-12-04).

Untested!
---
 src/tun_darwin.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/tun_darwin.go b/src/tun_darwin.go
index 87f6af6..a984e94 100644
--- a/src/tun_darwin.go
+++ b/src/tun_darwin.go
@@ -184,10 +184,14 @@ func (t *NativeTUN) Events() chan TUNEvent {
 	return t.events
 }
 
-func (t *NativeTUN) Read(to []byte) (int, error) {
+func (t *NativeTUN) Read(to []byte, offset int) (int, error) {
+	to = to[offset:]
+
 	t.rMu.Lock()
 	defer t.rMu.Unlock()
 
+	// TODO: implement in-place read
+
 	if cap(t.rBuf) < len(to)+4 {
 		t.rBuf = make([]byte, len(to)+4)
 	}
@@ -198,15 +202,18 @@ func (t *NativeTUN) Read(to []byte) (int, error) {
 	return n - 4, err
 }
 
-func (t *NativeTUN) Write(from []byte) (int, error) {
+func (t *NativeTUN) Write(from []byte, offset int) (int, error) {
 
-	if len(from) == 0 {
+	if len(from) < offset {
 		return 0, unix.EIO
 	}
+	from := from[offset:]
 
 	t.wMu.Lock()
 	defer t.wMu.Unlock()
 
+	// TODO: implement in-place write
+
 	if cap(t.wBuf) < len(from)+4 {
 		t.wBuf = make([]byte, len(from)+4)
 	}
-- 
2.15.1