--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -328,6 +328,13 @@ typedef struct {
 } ngx_http_upstream_next_t;
 
 
+typedef struct {
+    ngx_str_t   key;
+    ngx_str_t   value;
+    ngx_uint_t  skip_empty;
+} ngx_http_upstream_param_t;
+
+
 ngx_int_t ngx_http_upstream_header_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 
@@ -337,6 +344,8 @@ ngx_http_upstream_srv_conf_t *ngx_http_u
     ngx_url_t *u, ngx_uint_t flags);
 char *ngx_http_upstream_bind_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
+char *ngx_http_upstream_param_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
 ngx_int_t ngx_http_upstream_hide_headers_hash(ngx_conf_t *cf,
     ngx_http_upstream_conf_t *conf, ngx_http_upstream_conf_t *prev,
     ngx_str_t *default_hide_headers, ngx_hash_init_t *hash);