have the tunConn close things after a 2 minute timeout

src/tuntap/conn.go

@@ -2,6 +2,7 @@ package tuntap
 
 import (
 	"errors"
+	"time"
 
 	"github.com/yggdrasil-network/yggdrasil-go/src/address"
 	"github.com/yggdrasil-network/yggdrasil-go/src/util"
@@ -14,19 +15,28 @@ type tunConn struct {
 	addr  address.Address
 	snet  address.Subnet
 	send  chan []byte
-	stop chan interface{}
+	stop  chan struct{}
+	alive chan struct{}
 }
 
 func (s *tunConn) close() {
 	s.tun.mutex.Lock()
+	defer s.tun.mutex.Unlock()
 	s._close_nomutex()
-	s.tun.mutex.Unlock()
 }
 
 func (s *tunConn) _close_nomutex() {
+	s.conn.Close()
 	delete(s.tun.addrToConn, s.addr)
 	delete(s.tun.subnetToConn, s.snet)
-	close(s.stop)
+	func() {
+		defer func() { recover() }()
+		close(s.stop) // Closes reader/writer goroutines
+	}()
+	func() {
+		defer func() { recover() }()
+		close(s.alive) // Closes timeout goroutine
+	}()
 }
 
 func (s *tunConn) reader() error {
@@ -43,7 +53,7 @@ func (s *tunConn) reader() error {
 	b := make([]byte, 65535)
 	for {
 		go func() {
-			// TODO read timeout and close
+			// TODO don't start a new goroutine for every packet read, this is probably a big part of the slowdowns we saw when refactoring
 			if n, err = s.conn.Read(b); err != nil {
 				s.tun.log.Errorln(s.conn.String(), "TUN/TAP conn read error:", err)
 				return
@@ -60,6 +70,7 @@ func (s *tunConn) reader() error {
 					util.PutBytes(bs)
 				}
 			}
+			s.stillAlive() // TODO? Only stay alive if we read >0 bytes?
 		case <-s.stop:
 			s.tun.log.Debugln("Stopping conn reader for", s)
 			return nil
@@ -89,6 +100,33 @@ func (s *tunConn) writer() error {
 				s.tun.log.Errorln(s.conn.String(), "TUN/TAP conn write error:", err)
 			}
 			util.PutBytes(b)
+			s.stillAlive()
+		}
+	}
+}
+
+func (s *tunConn) stillAlive() {
+	select {
+	case s.alive <- struct{}{}:
+	default:
+	}
+}
+
+func (s *tunConn) checkForTimeouts() error {
+	const timeout = 2 * time.Minute
+	timer := time.NewTimer(timeout)
+	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(timeout)
+		case <-timer.C:
+			return errors.New("timed out")
 		}
 	}
 }

src/tuntap/tun.go

@@ -232,7 +232,8 @@ func (tun *TunAdapter) wrap(conn *yggdrasil.Conn) (c *tunConn, err error) {
 		tun:   tun,
 		conn:  conn,
 		send:  make(chan []byte, 32), // TODO: is this a sensible value?
-		stop: make(chan interface{}),
+		stop:  make(chan struct{}),
+		alive: make(chan struct{}, 1),
 	}
 	// Get the remote address and subnet of the other side
 	remoteNodeID := conn.RemoteAddr()
@@ -259,6 +260,7 @@ 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
 }