code: func (s *APIServer) upsertTunnelConnection(auth ClientI, w http.ResponseWriter, r *http.Request, p httprouter.Params, version string) (interface{}, error) {
  	var req upsertTunnelConnectionRawReq
  	if err := httplib.ReadJSON(r, &req); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	conn, err := services.UnmarshalTunnelConnection(req.TunnelConnection)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	if err := auth.UpsertTunnelConnection(conn); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return message("ok"), nil
  }
docs: // upsertTunnelConnection updates or inserts tunnel connection