From eec70bf2f22028a1cae5fe60f8a89dfbb84bc1b0 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Wed, 17 Jul 2019 13:53:16 +0100
Subject: [PATCH] Remove stillAlive code from TUN/TAP conn as it is no longer
 required with the new deadlines

---
 src/tuntap/conn.go | 45 ++++++++++-----------------------------------
 src/tuntap/tun.go  |  1 -
 2 files changed, 10 insertions(+), 36 deletions(-)

diff --git a/src/tuntap/conn.go b/src/tuntap/conn.go
index c5e6e81b..4cc880c1 100644
--- a/src/tuntap/conn.go
+++ b/src/tuntap/conn.go
@@ -64,16 +64,19 @@ func (s *tunConn) reader() error {
 			s.conn.SetReadDeadline(time.Now().Add(tunConnTimeout))
 			if n, err = s.conn.Read(b); err != nil {
 				s.tun.log.Errorln(s.conn.String(), "TUN/TAP conn read error:", err)
-				if e, eok := err.(yggdrasil.ConnError); eok {
+				if e, eok := err.(yggdrasil.ConnError); eok && !e.Temporary() {
 					s.tun.log.Debugln("Conn reader helper", s, "error:", e)
 					switch {
-					case e.Temporary():
-						fallthrough
+					// The timeout probably means we've waited for the timeout period and
+					// nothing has happened so close the connection
 					case e.Timeout():
-						read <- false
+						s.close()
 						continue
+					// The connection is already closed, so we anticipate that the main
+					// reader goroutine has already exited. Also stop in that case
 					case e.Closed():
-						fallthrough
+						return
+					// Some other case that we don't know about - close the connection
 					default:
 						s.close()
 						return
@@ -86,7 +89,7 @@ func (s *tunConn) reader() error {
 	}()
 	for {
 		select {
-		case r, ok := <-read:
+		case r := <-read:
 			if r && n > 0 {
 				bs := append(util.GetBytes(), b[:n]...)
 				select {
@@ -95,9 +98,6 @@ func (s *tunConn) reader() error {
 					util.PutBytes(bs)
 				}
 			}
-			if ok {
-				s.stillAlive() // TODO? Only stay alive if we read >0 bytes?
-			}
 		case <-s.stop:
 			return nil
 		}
@@ -123,6 +123,7 @@ func (s *tunConn) writer() error {
 				return errors.New("send closed")
 			}
 			// TODO write timeout and close
+			s.conn.SetWriteDeadline(time.Now().Add(tunConnTimeout))
 			if _, err := s.conn.Write(b); err != nil {
 				e, eok := err.(yggdrasil.ConnError)
 				if !eok {
@@ -141,32 +142,6 @@ func (s *tunConn) writer() error {
 				}
 			}
 			util.PutBytes(b)
-			s.stillAlive()
-		}
-	}
-}
-
-func (s *tunConn) stillAlive() {
-	select {
-	case s.alive <- struct{}{}:
-	default:
-	}
-}
-
-func (s *tunConn) checkForTimeouts() error {
-	timer := time.NewTimer(tunConnTimeout)
-	defer util.TimerStop(timer)
-	defer s.close()
-	for {
-		select {
-		case _, ok := <-s.alive:
-			if !ok {
-				return errors.New("connection closed")
-			}
-			util.TimerStop(timer)
-			timer.Reset(tunConnTimeout)
-		case <-timer.C:
-			return errors.New("timed out")
 		}
 	}
 }
diff --git a/src/tuntap/tun.go b/src/tuntap/tun.go
index cc124971..72bdd2f0 100644
--- a/src/tuntap/tun.go
+++ b/src/tuntap/tun.go
@@ -259,7 +259,6 @@ func (tun *TunAdapter) wrap(conn *yggdrasil.Conn) (c *tunConn, err error) {
 	// Start the connection goroutines
 	go s.reader()
 	go s.writer()
-	go s.checkForTimeouts()
 	// Return
 	return c, err
 }