fix accidental early client.Close()

cmd/telebit/telebit.go

@@ -251,9 +251,9 @@ func main() {
 			fmt.Printf("[debug] Accepting API or WebSocket client %q\n", *apiHostname)
 			listener.Feed(client)
 			fmt.Printf("[debug] done with %q client\n", *apiHostname)
-			// TODO use a more correct non-error error?
-			// or perhaps (ok, error) or (handled, error)?
-			return io.EOF
+			// nil now means handler in-progress (go routine)
+			// EOF now means handler finished
+			return nil
 		}))
 	}
 	for _, fwd := range forwards {
@@ -369,7 +369,8 @@ func routeSubscribersAndClients(client net.Conn) error {
 	labels := strings.Split(servername, ".")
 	n := len(labels)
 	if n < 3 {
-		return nil
+		// skip
+		return telebit.ErrNotHandled
 	}
 	for i := 1; i < n-1; i++ {
 		wildname := "*." + strings.Join(labels[1:], ".")
@@ -379,7 +380,7 @@ func routeSubscribersAndClients(client net.Conn) error {
 	}
 
 	// skip
-	return nil
+	return telebit.ErrNotHandled
 }
 
 // tryToServeName picks the server tunnel with the least connections, if any

mplexer/connwrap.go

@@ -117,28 +117,21 @@ func (c *ConnWrap) Servername() string {
 	}
 
 	// this will get the servername
-	c.isTerminated()
+	_ = c.isEncrypted()
 	return c.servername
 }
 
-// isTerminated returns true if net.Conn is either a ConnWrap{ tls.Conn },
-// or a telebit.Conn with a non-encrypted `scheme` such as "tcp" or "http".
-func (c *ConnWrap) isTerminated() bool {
-	// TODO look at SNI, may need context for Peek() timeout
-	/*
-		if nil != c.Plain {
-			return true
-		}
-	*/
+// isEncrypted returns true if peeking at net.Conn reveals that it is TLS-encrypted
+func (c *ConnWrap) isEncrypted() bool {
 	if nil != c.encrypted {
-		return !*c.encrypted
+		return *c.encrypted
 	}
 
-	// how to know how many bytes to read? really needs timeout
+	// TODO: how to allow / detect / handle protocols where the server hello happens first?
 	c.SetDeadline(time.Now().Add(5 * time.Second))
 	n := 6
 	b, _ := c.Peek(n)
-	fmt.Println("Peek(n)", b, string(b))
+	fmt.Println("[debug] Peek(n)", b, string(b))
 	defer c.SetDeadline(time.Time{})
 	var encrypted bool
 	if len(b) >= n {
@@ -155,30 +148,16 @@ func (c *ConnWrap) isTerminated() bool {
 			b, err := c.Peek(n - 1 + length)
 			if nil != err {
 				c.encrypted = &encrypted
-				return !*c.encrypted
+				return *c.encrypted
 			}
 			c.servername, _ = sni.GetHostname(b)
 			encrypted = true
 			c.encrypted = &encrypted
-			return !*c.encrypted
+			return *c.encrypted
 		}
 	}
 	c.encrypted = &encrypted
-	return !*c.encrypted
-	/*
-		if nil != err {
-			return true
-		}
-
-		switch conn := c.Conn.(type) {
-		case *ConnWrap:
-			return conn.isTerminated()
-		case *Conn:
-			_, ok := encryptedSchemes[string(conn.relayTargetAddr.scheme)]
-			return !ok
-		}
-		return false
-	*/
+	return *c.encrypted
 }
 
 // LocalAddr returns the local network address.

mplexer/listener.go

@@ -76,13 +76,16 @@ func Serve(listener net.Listener, mux Handler) error {
 		}
 
 		go func() {
-			err = mux.Serve(client)
-			if nil != err {
+			// nil means being handled
+			// non-nil means handled
+			// io.EOF means handled with success
+			if err := mux.Serve(client); nil != err {
 				if io.EOF != err && io.ErrClosedPipe != err && !strings.Contains(err.Error(), errNetClosing) {
 					fmt.Printf("client could not be served: %q\n", err.Error())
 				}
-			}
+				fmt.Println("[debug] closing original client", err)
 				client.Close()
+			}
 		}()
 	}
 }

mplexer/routemux.go

@@ -1,6 +1,7 @@
 package telebit
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -18,6 +19,8 @@ type RouteMux struct {
 	routes         []meta
 }
 
+var ErrNotHandled = errors.New("connection not handled")
+
 type meta struct {
 	addr      string
 	handler   Handler
@@ -72,11 +75,10 @@ func (m *RouteMux) Serve(client net.Conn) error {
 		fmt.Println("Meta:", meta.addr, servername)
 		if servername == meta.addr || "*" == meta.addr || port == meta.addr {
 			//fmt.Println("[debug] test of route:", meta)
-			if err := meta.handler.Serve(wconn); nil != err {
-				// error should be EOF if successful
+			// Only keep trying handlers if ErrNotHandled was returned
+			if err := meta.handler.Serve(wconn); ErrNotHandled != err {
 				return err
 			}
-			// nil err means skipped
 		}
 	}
 
@@ -121,9 +123,8 @@ func (m *RouteMux) HandleTLS(servername string, acme *ACME, handler Handler) err
 				panic("HandleTLS is special in that it must receive &ConnWrap{ Conn: conn }")
 			}
 
-			if wconn.isTerminated() {
-				// nil to skip
-				return nil
+			if !wconn.isEncrypted() {
+				return ErrNotHandled
 			}
 
 			//NewTerminator(acme, handler)(client)

mplexer/telebit.go

@@ -253,7 +253,7 @@ func TerminateTLS(client net.Conn, acme *ACME) net.Conn {
 		wconn := &ConnWrap{
 			Conn: client,
 		}
-		wconn.isTerminated()
+		_ = wconn.isEncrypted()
 		servername = wconn.Servername()
 		scheme = wconn.Scheme()
 		client = wconn