Style and minor fixes, main package

cmd/relaysrv/protocol_listener.go

@@ -27,7 +27,6 @@ func protocolListener(addr string, config *tls.Config) {
 
 	for {
 		conn, err := listener.Accept()
-		setTCPOptions(conn)
 		if err != nil {
 			if debug {
 				log.Println(err)
@@ -35,6 +34,8 @@ func protocolListener(addr string, config *tls.Config) {
 			continue
 		}
 
+		setTCPOptions(conn)
+
 		if debug {
 			log.Println("Protocol listener accepted connection from", conn.RemoteAddr())
 		}
@@ -74,16 +75,12 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 	errors := make(chan error, 1)
 	outbox := make(chan interface{})
 
-	go func(conn net.Conn, message chan<- interface{}, errors chan<- error) {
+	// Read messages from the connection and send them on the messages
-		for {
+	// channel. When there is an error, send it on the error channel and
-			msg, err := protocol.ReadMessage(conn)
+	// return. Applies also when the connection gets closed, so the pattern
-			if err != nil {
+	// below is to close the connection on error, then wait for the error
-				errors <- err
+	// signal from messageReader to exit.
-				return
+	go messageReader(conn, messages, errors)
-			}
-			messages <- msg
-		}
-	}(conn, messages, errors)
 
 	pingTicker := time.NewTicker(pingInterval)
 	timeoutTicker := time.NewTimer(networkTimeout)
@@ -96,6 +93,7 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 			if debug {
 				log.Printf("Message %T from %s", message, id)
 			}
+
 			switch msg := message.(type) {
 			case protocol.JoinRelayRequest:
 				outboxesMut.RLock()
@@ -116,6 +114,7 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 				joined = true
 
 				protocol.WriteMessage(conn, protocol.ResponseSuccess)
+
 			case protocol.ConnectRequest:
 				requestedPeer := syncthingprotocol.DeviceIDFromBytes(msg.ID)
 				outboxesMut.RLock()
@@ -151,7 +150,10 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 					log.Println("Sent invitation from", id, "to", requestedPeer)
 				}
 				conn.Close()
+
 			case protocol.Pong:
+				// Nothing
+
 			default:
 				if debug {
 					log.Printf("Unknown message %s: %T", id, message)
@@ -159,21 +161,25 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 				protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
 				conn.Close()
 			}
+
 		case err := <-errors:
 			if debug {
 				log.Printf("Closing connection %s: %s", id, err)
 			}
-			// Potentially closing a second time.
 			close(outbox)
+
+			// Potentially closing a second time.
 			conn.Close()
-			// Only delete the outbox if the client join, as it migth be a
+
-			// lookup request coming from the same client.
+			// Only delete the outbox if the client is joined, as it might be
+			// a lookup request coming from the same client.
 			if joined {
 				outboxesMut.Lock()
 				delete(outboxes, id)
 				outboxesMut.Unlock()
 			}
 			return
+
 		case <-pingTicker.C:
 			if !joined {
 				if debug {
@@ -189,6 +195,7 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 				}
 				conn.Close()
 			}
+
 		case <-timeoutTicker.C:
 			// We should receive a error from the reader loop, which will cause
 			// us to quit this loop.
@@ -196,6 +203,7 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 				log.Printf("%s timed out", id)
 			}
 			conn.Close()
+
 		case msg := <-outbox:
 			if debug {
 				log.Printf("Sending message %T to %s", msg, id)
@@ -209,3 +217,14 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 		}
 	}
 }
+
+func messageReader(conn net.Conn, messages chan<- interface{}, errors chan<- error) {
+	for {
+		msg, err := protocol.ReadMessage(conn)
+		if err != nil {
+			errors <- err
+			return
+		}
+		messages <- msg
+	}
+}

cmd/relaysrv/session_listener.go

@@ -18,7 +18,6 @@ func sessionListener(addr string) {
 
 	for {
 		conn, err := listener.Accept()
-		setTCPOptions(conn)
 		if err != nil {
 			if debug {
 				log.Println(err)
@@ -26,6 +25,8 @@ func sessionListener(addr string) {
 			continue
 		}
 
+		setTCPOptions(conn)
+
 		if debug {
 			log.Println("Session listener accepted connection from", conn.RemoteAddr())
 		}
@@ -35,10 +36,17 @@ func sessionListener(addr string) {
 }
 
 func sessionConnectionHandler(conn net.Conn) {
-	conn.SetDeadline(time.Now().Add(messageTimeout))
+	defer conn.Close()
+
+	if err := conn.SetDeadline(time.Now().Add(messageTimeout)); err != nil {
+		if debug {
+			log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
+		}
+		return
+	}
+
 	message, err := protocol.ReadMessage(conn)
 	if err != nil {
-		conn.Close()
 		return
 	}
 
@@ -51,7 +59,6 @@ func sessionConnectionHandler(conn net.Conn) {
 
 		if ses == nil {
 			protocol.WriteMessage(conn, protocol.ResponseNotFound)
-			conn.Close()
 			return
 		}
 
@@ -60,24 +67,26 @@ func sessionConnectionHandler(conn net.Conn) {
 				log.Println("Failed to add", conn.RemoteAddr(), "to session", ses)
 			}
 			protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
-			conn.Close()
 			return
 		}
 
-		err := protocol.WriteMessage(conn, protocol.ResponseSuccess)
+		if err := protocol.WriteMessage(conn, protocol.ResponseSuccess); err != nil {
-		if err != nil {
 			if debug {
 				log.Println("Failed to send session join response to ", conn.RemoteAddr(), "for", ses)
 			}
-			conn.Close()
 			return
 		}
-		conn.SetDeadline(time.Time{})
+
+		if err := conn.SetDeadline(time.Time{}); err != nil {
+			if debug {
+				log.Println("Weird error setting deadline:", err, "on", conn.RemoteAddr())
+			}
+			return
+		}
 	default:
 		if debug {
 			log.Println("Unexpected message from", conn.RemoteAddr(), message)
 		}
 		protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
-		conn.Close()
 	}
 }