Hello every body!

I want to add http_400 in directive proxy_next_upstream of module upstream:

1. Add code below in file src/http/ngx_http_upstream.h:
#define NGX_HTTP_UPSTREAM_FT_HTTP_502 0x00000020
#define NGX_HTTP_UPSTREAM_FT_HTTP_503 0x00000040
#define NGX_HTTP_UPSTREAM_FT_HTTP_504 0x00000080
#define NGX_HTTP_UPSTREAM_FT_HTTP_404 0x00000100

#define NGX_HTTP_UPSTREAM_FT_HTTP_400 0x00000120 //---> not right

2.Add code below in file ngx_http_upstream.c:

{ 500, NGX_HTTP_UPSTREAM_FT_HTTP_500 },
{ 502, NGX_HTTP_UPSTREAM_FT_HTTP_502 },
{ 503, NGX_HTTP_UPSTREAM_FT_HTTP_503 },
{ 504, NGX_HTTP_UPSTREAM_FT_HTTP_504 },
{ 404, NGX_HTTP_UPSTREAM_FT_HTTP_404 },

{ 400, NGX_HTTP_UPSTREAM_FT_HTTP_400 }, //add code here

3.Add code below in file src/http/modules/ngx_http_proxy_module.c:

{ ngx_string("http_500"), NGX_HTTP_UPSTREAM_FT_HTTP_500 },
{ ngx_string("http_502"), NGX_HTTP_UPSTREAM_FT_HTTP_502 },
{ ngx_string("http_503"), NGX_HTTP_UPSTREAM_FT_HTTP_503 },
{ ngx_string("http_504"), NGX_HTTP_UPSTREAM_FT_HTTP_504 },
{ ngx_string("http_404"), NGX_HTTP_UPSTREAM_FT_HTTP_404 },

{ ngx_string("http_400"), NGX_HTTP_UPSTREAM_FT_HTTP_400 }, // add code here

Plz help me
Thank you so much.