--- a/src/stream/ngx_stream_variables.c
+++ b/src/stream/ngx_stream_variables.c
@@ -10,6 +10,8 @@
 #include <ngx_stream.h>
 #include <nginx.h>
 
+static ngx_stream_variable_t *ngx_stream_add_prefix_variable(ngx_conf_t *cf,
+    ngx_str_t *name, ngx_uint_t flags);
 
 static ngx_int_t ngx_stream_variable_binary_remote_addr(
     ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data);
@@ -137,6 +139,10 @@ ngx_stream_add_variable(ngx_conf_t *cf, 
         return NULL;
     }
 
+    if (flags & NGX_STREAM_VAR_PREFIX) {
+        return ngx_stream_add_prefix_variable(cf, name, flags);
+    }
+
     cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
 
     key = cmcf->variables_keys->keys.elts;
@@ -155,6 +161,8 @@ ngx_stream_add_variable(ngx_conf_t *cf, 
             return NULL;
         }
 
+        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+
         return v;
     }
 
@@ -193,6 +201,60 @@ ngx_stream_add_variable(ngx_conf_t *cf, 
 }
 
 
+static ngx_stream_variable_t *
+ngx_stream_add_prefix_variable(ngx_conf_t *cf, ngx_str_t *name,
+    ngx_uint_t flags)
+{
+    ngx_uint_t                    i;
+    ngx_stream_variable_t        *v;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    v = cmcf->prefix_variables.elts;
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len != v[i].name.len
+            || ngx_strncasecmp(name->data, v[i].name.data, name->len) != 0)
+        {
+            continue;
+        }
+
+        v = &v[i];
+
+        if (!(v->flags & NGX_STREAM_VAR_CHANGEABLE)) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "the duplicate \"%V\" variable", name);
+            return NULL;
+        }
+
+        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+
+        return v;
+    }
+
+    v = ngx_array_push(&cmcf->prefix_variables);
+    if (v == NULL) {
+        return NULL;
+    }
+
+    v->name.len = name->len;
+    v->name.data = ngx_pnalloc(cf->pool, name->len);
+    if (v->name.data == NULL) {
+        return NULL;
+    }
+
+    ngx_strlow(v->name.data, name->data, name->len);
+
+    v->set_handler = NULL;
+    v->get_handler = NULL;
+    v->data = 0;
+    v->flags = flags;
+    v->index = 0;
+
+    return v;
+}
+
+
 ngx_int_t
 ngx_stream_get_variable_index(ngx_conf_t *cf, ngx_str_t *name)
 {
@@ -327,6 +389,8 @@ ngx_stream_variable_value_t *
 ngx_stream_get_variable(ngx_stream_session_t *s, ngx_str_t *name,
     ngx_uint_t key)
 {
+    size_t                        len;
+    ngx_uint_t                    i, n;
     ngx_stream_variable_t        *v;
     ngx_stream_variable_value_t  *vv;
     ngx_stream_core_main_conf_t  *cmcf;
@@ -365,6 +429,28 @@ ngx_stream_get_variable(ngx_stream_sessi
         return NULL;
     }
 
+    len = 0;
+
+    v = cmcf->prefix_variables.elts;
+    n = cmcf->prefix_variables.nelts;
+
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len >= v[i].name.len && name->len > len
+            && ngx_strncmp(name->data, v[i].name.data, v[i].name.len) == 0)
+        {
+            len = v[i].name.len;
+            n = i;
+        }
+    }
+
+    if (n != cmcf->prefix_variables.nelts) {
+        if (v[n].get_handler(s, vv, (uintptr_t) name) == NGX_OK) {
+            return vv;
+        }
+
+        return NULL;
+    }
+
     vv->not_found = 1;
 
     return vv;
@@ -1000,7 +1086,6 @@ ngx_stream_regex_exec(ngx_stream_session
 ngx_int_t
 ngx_stream_variables_add_core_vars(ngx_conf_t *cf)
 {
-    ngx_int_t                     rc;
     ngx_stream_variable_t        *cv, *v;
     ngx_stream_core_main_conf_t  *cmcf;
 
@@ -1021,27 +1106,20 @@ ngx_stream_variables_add_core_vars(ngx_c
         return NGX_ERROR;
     }
 
+    if (ngx_array_init(&cmcf->prefix_variables, cf->pool, 8,
+                       sizeof(ngx_stream_variable_t))
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
     for (cv = ngx_stream_core_variables; cv->name.len; cv++) {
-        v = ngx_palloc(cf->pool, sizeof(ngx_stream_variable_t));
+        v = ngx_stream_add_variable(cf, &cv->name, cv->flags);
         if (v == NULL) {
             return NGX_ERROR;
         }
 
         *v = *cv;
-
-        rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v,
-                              NGX_HASH_READONLY_KEY);
-
-        if (rc == NGX_OK) {
-            continue;
-        }
-
-        if (rc == NGX_BUSY) {
-            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                               "conflicting variable name \"%V\"", &v->name);
-        }
-
-        return NGX_ERROR;
     }
 
     return NGX_OK;
@@ -1051,10 +1129,11 @@ ngx_stream_variables_add_core_vars(ngx_c
 ngx_int_t
 ngx_stream_variables_init_vars(ngx_conf_t *cf)
 {
+    size_t                        len;
     ngx_uint_t                    i, n;
     ngx_hash_key_t               *key;
     ngx_hash_init_t               hash;
-    ngx_stream_variable_t        *v, *av;
+    ngx_stream_variable_t        *v, *av, *pv;
     ngx_stream_core_main_conf_t  *cmcf;
 
     /* set the handlers for the indexed stream variables */
@@ -1062,6 +1141,7 @@ ngx_stream_variables_init_vars(ngx_conf_
     cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
 
     v = cmcf->variables.elts;
+    pv = cmcf->prefix_variables.elts;
     key = cmcf->variables_keys->keys.elts;
 
     for (i = 0; i < cmcf->variables.nelts; i++) {
@@ -1082,7 +1162,9 @@ ngx_stream_variables_init_vars(ngx_conf_
 
                 av->index = i;
 
-                if (av->get_handler == NULL) {
+                if (av->get_handler == NULL
+                    || (av->flags & NGX_STREAM_VAR_WEAK))
+                {
                     break;
                 }
 
@@ -1090,10 +1172,32 @@ ngx_stream_variables_init_vars(ngx_conf_
             }
         }
 
-        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
-                      "unknown \"%V\" variable", &v[i].name);
+        len = 0;
+        av = NULL;
+
+        for (n = 0; n < cmcf->prefix_variables.nelts; n++) {
+            if (v[i].name.len >= pv[n].name.len && v[i].name.len > len
+                && ngx_strncmp(v[i].name.data, pv[n].name.data, pv[n].name.len)
+                   == 0)
+            {
+                av = &pv[n];
+                len = pv[n].name.len;
+            }
+        }
 
-        return NGX_ERROR;
+        if (av) {
+            v[i].get_handler = av->get_handler;
+            v[i].data = (uintptr_t) &v[i].name;
+            v[i].flags = av->flags;
+
+            goto next;
+         }
+
+        if (v[i].get_handler == NULL) {
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                          "unknown \"%V\" variable", &v[i].name);
+            return NGX_ERROR;
+        }
 
     next:
         continue;