Update ttrpc to v1.2.1

Signed-off-by: Derek McGowan <derek@mcg.dev>

vendor/github.com/containerd/ttrpc/server.go

@@ -121,12 +121,18 @@ func (s *Server) Serve(ctx context.Context, l net.Listener) error {
 
 		approved, handshake, err := handshaker.Handshake(ctx, conn)
 		if err != nil {
-			logrus.WithError(err).Errorf("ttrpc: refusing connection after handshake")
+			logrus.WithError(err).Error("ttrpc: refusing connection after handshake")
+			conn.Close()
+			continue
+		}
+
+		sc, err := s.newConn(approved, handshake)
+		if err != nil {
+			logrus.WithError(err).Error("ttrpc: create connection failed")
 			conn.Close()
 			continue
 		}
 
-		sc := s.newConn(approved, handshake)
 		go sc.run(ctx)
 	}
 }
@@ -145,15 +151,20 @@ func (s *Server) Shutdown(ctx context.Context) error {
 	ticker := time.NewTicker(200 * time.Millisecond)
 	defer ticker.Stop()
 	for {
-		if s.closeIdleConns() {
-			return lnerr
+		s.closeIdleConns()
+
+		if s.countConnection() == 0 {
+			break
 		}
+
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
 		case <-ticker.C:
 		}
 	}
+
+	return lnerr
 }
 
 // Close the server without waiting for active connections.
@@ -205,11 +216,18 @@ func (s *Server) closeListeners() error {
 	return err
 }
 
-func (s *Server) addConnection(c *serverConn) {
+func (s *Server) addConnection(c *serverConn) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
+	select {
+	case <-s.done:
+		return ErrServerClosed
+	default:
+	}
+
 	s.connections[c] = struct{}{}
+	return nil
 }
 
 func (s *Server) delConnection(c *serverConn) {
@@ -226,20 +244,17 @@ func (s *Server) countConnection() int {
 	return len(s.connections)
 }
 
-func (s *Server) closeIdleConns() bool {
+func (s *Server) closeIdleConns() {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	quiescent := true
+
 	for c := range s.connections {
-		st, ok := c.getState()
-		if !ok || st != connStateIdle {
-			quiescent = false
+		if st, ok := c.getState(); !ok || st == connStateActive {
 			continue
 		}
 		c.close()
 		delete(s.connections, c)
 	}
-	return quiescent
 }
 
 type connState int
@@ -263,7 +278,7 @@ func (cs connState) String() string {
 	}
 }
 
-func (s *Server) newConn(conn net.Conn, handshake interface{}) *serverConn {
+func (s *Server) newConn(conn net.Conn, handshake interface{}) (*serverConn, error) {
 	c := &serverConn{
 		server:    s,
 		conn:      conn,
@@ -271,8 +286,11 @@ func (s *Server) newConn(conn net.Conn, handshake interface{}) *serverConn {
 		shutdown:  make(chan struct{}),
 	}
 	c.setState(connStateIdle)
-	s.addConnection(c)
-	return c
+	if err := s.addConnection(c); err != nil {
+		c.close()
+		return nil, err
+	}
+	return c, nil
 }
 
 type serverConn struct {