introduce 494 code "Request Header Too Large"

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index 55e220a..bd51e06 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c

@@ -978,10 +978,13 @@
                 if (rv == NGX_DECLINED) {
                     p = r->header_name_start;
 
+                    r->lingering_close = 1;
+
                     if (p == NULL) {
                         ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                       "client sent too large request");
-                        ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
+                        ngx_http_finalize_request(r,
+                                            NGX_HTTP_REQUEST_HEADER_TOO_LARGE);
                         return;
                     }
 
@@ -995,7 +998,9 @@
                     ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                   "client sent too long header line: \"%*s\"",
                                   len, r->header_name_start);
-                    ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
+
+                    ngx_http_finalize_request(r,
+                                            NGX_HTTP_REQUEST_HEADER_TOO_LARGE);
                     return;
                 }
             }

diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index b58c4d7..c20810e 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h

@@ -95,7 +95,9 @@
 /* The special code to close connection without any response */
 #define NGX_HTTP_CLOSE                     444
 
-#define NGX_HTTP_NGINX_CODES               495
+#define NGX_HTTP_NGINX_CODES               494
+
+#define NGX_HTTP_REQUEST_HEADER_TOO_LARGE  494
 
 #define NGX_HTTPS_CERT_ERROR               495
 #define NGX_HTTPS_NO_CERT                  496

diff --git a/src/http/ngx_http_special_response.c b/src/http/ngx_http_special_response.c
index 487c65a..ed87fd0 100644
--- a/src/http/ngx_http_special_response.c
+++ b/src/http/ngx_http_special_response.c

@@ -201,6 +201,16 @@
 ;
 
 
+static char ngx_http_error_494_page[] =
+"<html>" CRLF
+"<head><title>400 Request Header Or Cookie Too Large</title></head>"
+CRLF
+"<body bgcolor=\"white\">" CRLF
+"<center><h1>400 Bad Request</h1></center>" CRLF
+"<center>Request Header Or Cookie Too Large</center>" CRLF
+;
+
+
 static char ngx_http_error_495_page[] =
 "<html>" CRLF
 "<head><title>400 The SSL certificate error</title></head>"
@@ -315,6 +325,7 @@
 #define NGX_HTTP_LAST_LEVEL_400  417
 #define NGX_HTTP_LEVEL_400       (NGX_HTTP_LAST_LEVEL_400 - 400)
 
+    ngx_string(ngx_http_error_494_page), /* 494, request header too large */
     ngx_string(ngx_http_error_495_page), /* 495, https certificate error */
     ngx_string(ngx_http_error_496_page), /* 496, https no certificate */
     ngx_string(ngx_http_error_497_page), /* 497, http to https */
@@ -440,6 +451,7 @@
             case NGX_HTTP_TO_HTTPS:
             case NGX_HTTPS_CERT_ERROR:
             case NGX_HTTPS_NO_CERT:
+            case NGX_HTTP_REQUEST_HEADER_TOO_LARGE:
                 r->err_status = NGX_HTTP_BAD_REQUEST;
                 break;
         }