NGX_HTTP_LAST_LEVEL_400 112 http/ngx_http_header_filter_module.c #define NGX_HTTP_LEVEL_400 (NGX_HTTP_LAST_LEVEL_400 - 400) NGX_HTTP_LAST_LEVEL_400 250 http/ngx_http_header_filter_module.c && status < NGX_HTTP_LAST_LEVEL_400) NGX_HTTP_LAST_LEVEL_400 326 http/ngx_http_special_response.c #define NGX_HTTP_LEVEL_400 (NGX_HTTP_LAST_LEVEL_400 - 400) NGX_HTTP_LAST_LEVEL_400 437 http/ngx_http_special_response.c && error < NGX_HTTP_LAST_LEVEL_400)