new file mode 100644
--- /dev/null
+++ b/src/stream/ngx_stream_variables.c
@@ -0,0 +1,621 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_stream.h>
+#include <nginx.h>
+
+
+static ngx_int_t ngx_stream_variable_nginx_version(ngx_stream_session_t *s,
+    ngx_stream_variable_value_t *v, uintptr_t data);
+
+
+static ngx_stream_variable_t  ngx_stream_core_variables[] = {
+
+    { ngx_string("nginx_version"), NULL, ngx_stream_variable_nginx_version,
+      0, 0, 0 },
+
+    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+};
+
+
+ngx_stream_variable_value_t  ngx_stream_variable_null_value =
+    ngx_stream_variable("");
+ngx_stream_variable_value_t  ngx_stream_variable_true_value =
+    ngx_stream_variable("1");
+
+
+ngx_stream_variable_t *
+ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
+{
+    ngx_int_t                     rc;
+    ngx_uint_t                    i;
+    ngx_hash_key_t               *key;
+    ngx_stream_variable_t        *v;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    if (name->len == 0) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid variable name \"$\"");
+        return NULL;
+    }
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    key = cmcf->variables_keys->keys.elts;
+    for (i = 0; i < cmcf->variables_keys->keys.nelts; i++) {
+        if (name->len != key[i].key.len
+            || ngx_strncasecmp(name->data, key[i].key.data, name->len) != 0)
+        {
+            continue;
+        }
+
+        v = key[i].value;
+
+        if (!(v->flags & NGX_STREAM_VAR_CHANGEABLE)) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "the duplicate \"%V\" variable", name);
+            return NULL;
+        }
+
+        return v;
+    }
+
+    v = ngx_palloc(cf->pool, sizeof(ngx_stream_variable_t));
+    if (v == NULL) {
+        return NULL;
+    }
+
+    v->name.len = name->len;
+    v->name.data = ngx_pnalloc(cf->pool, name->len);
+    if (v->name.data == NULL) {
+        return NULL;
+    }
+
+    ngx_strlow(v->name.data, name->data, name->len);
+
+    v->set_handler = NULL;
+    v->get_handler = NULL;
+    v->data = 0;
+    v->flags = flags;
+    v->index = 0;
+
+    rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v, 0);
+
+    if (rc == NGX_ERROR) {
+        return NULL;
+    }
+
+    if (rc == NGX_BUSY) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "conflicting variable name \"%V\"", name);
+        return NULL;
+    }
+
+    return v;
+}
+
+
+ngx_int_t
+ngx_stream_get_variable_index(ngx_conf_t *cf, ngx_str_t *name)
+{
+    ngx_uint_t                    i;
+    ngx_stream_variable_t        *v;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    if (name->len == 0) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid variable name \"$\"");
+        return NGX_ERROR;
+    }
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    v = cmcf->variables.elts;
+
+    if (v == NULL) {
+        if (ngx_array_init(&cmcf->variables, cf->pool, 4,
+                           sizeof(ngx_stream_variable_t))
+            != NGX_OK)
+        {
+            return NGX_ERROR;
+        }
+
+    } else {
+        for (i = 0; i < cmcf->variables.nelts; i++) {
+            if (name->len != v[i].name.len
+                || ngx_strncasecmp(name->data, v[i].name.data, name->len) != 0)
+            {
+                continue;
+            }
+
+            return i;
+        }
+    }
+
+    v = ngx_array_push(&cmcf->variables);
+    if (v == NULL) {
+        return NGX_ERROR;
+    }
+
+    v->name.len = name->len;
+    v->name.data = ngx_pnalloc(cf->pool, name->len);
+    if (v->name.data == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_strlow(v->name.data, name->data, name->len);
+
+    v->set_handler = NULL;
+    v->get_handler = NULL;
+    v->data = 0;
+    v->flags = 0;
+    v->index = cmcf->variables.nelts - 1;
+
+    return v->index;
+}
+
+
+ngx_stream_variable_value_t *
+ngx_stream_get_indexed_variable(ngx_stream_session_t *s, ngx_uint_t index)
+{
+    ngx_stream_variable_t        *v;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);
+
+    if (cmcf->variables.nelts <= index) {
+        ngx_log_error(NGX_LOG_ALERT, s->connection->log, 0,
+                      "unknown variable index: %ui", index);
+        return NULL;
+    }
+
+    if (s->variables[index].not_found || s->variables[index].valid) {
+        return &s->variables[index];
+    }
+
+    v = cmcf->variables.elts;
+
+    if (v[index].get_handler(s, &s->variables[index], v[index].data)
+        == NGX_OK)
+    {
+        if (v[index].flags & NGX_STREAM_VAR_NOCACHEABLE) {
+            s->variables[index].no_cacheable = 1;
+        }
+
+        return &s->variables[index];
+    }
+
+    s->variables[index].valid = 0;
+    s->variables[index].not_found = 1;
+
+    return NULL;
+}
+
+
+ngx_stream_variable_value_t *
+ngx_stream_get_flushed_variable(ngx_stream_session_t *s, ngx_uint_t index)
+{
+    ngx_stream_variable_value_t  *v;
+
+    v = &s->variables[index];
+
+    if (v->valid || v->not_found) {
+        if (!v->no_cacheable) {
+            return v;
+        }
+
+        v->valid = 0;
+        v->not_found = 0;
+    }
+
+    return ngx_stream_get_indexed_variable(s, index);
+}
+
+
+ngx_stream_variable_value_t *
+ngx_stream_get_variable(ngx_stream_session_t *s, ngx_str_t *name,
+    ngx_uint_t key)
+{
+    ngx_stream_variable_t        *v;
+    ngx_stream_variable_value_t  *vv;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);
+
+    v = ngx_hash_find(&cmcf->variables_hash, key, name->data, name->len);
+
+    if (v) {
+        if (v->flags & NGX_STREAM_VAR_INDEXED) {
+            return ngx_stream_get_flushed_variable(s, v->index);
+
+        } else {
+
+            vv = ngx_palloc(s->connection->pool,
+                            sizeof(ngx_stream_variable_value_t));
+
+            if (vv && v->get_handler(s, vv, v->data) == NGX_OK) {
+                return vv;
+            }
+
+            return NULL;
+        }
+    }
+
+    vv = ngx_palloc(s->connection->pool, sizeof(ngx_stream_variable_value_t));
+    if (vv == NULL) {
+        return NULL;
+    }
+
+    vv->not_found = 1;
+
+    return vv;
+}
+
+
+static ngx_int_t
+ngx_stream_variable_nginx_version(ngx_stream_session_t *s,
+    ngx_stream_variable_value_t *v, uintptr_t data)
+{
+    v->len = sizeof(NGINX_VERSION) - 1;
+    v->valid = 1;
+    v->no_cacheable = 0;
+    v->not_found = 0;
+    v->data = (u_char *) NGINX_VERSION;
+
+    return NGX_OK;
+}
+
+
+void *
+ngx_stream_map_find(ngx_stream_session_t *s, ngx_stream_map_t *map,
+    ngx_str_t *match)
+{
+    void        *value;
+    u_char      *low;
+    size_t       len;
+    ngx_uint_t   key;
+
+    len = match->len;
+
+    if (len) {
+        low = ngx_pnalloc(s->connection->pool, len);
+        if (low == NULL) {
+            return NULL;
+        }
+
+    } else {
+        low = NULL;
+    }
+
+    key = ngx_hash_strlow(low, match->data, len);
+
+    value = ngx_hash_find_combined(&map->hash, key, low, len);
+    if (value) {
+        return value;
+    }
+
+#if (NGX_PCRE)
+
+    if (len && map->nregex) {
+        ngx_int_t                n;
+        ngx_uint_t               i;
+        ngx_stream_map_regex_t  *reg;
+
+        reg = map->regex;
+
+        for (i = 0; i < map->nregex; i++) {
+
+            n = ngx_stream_regex_exec(s, reg[i].regex, match);
+
+            if (n == NGX_OK) {
+                return reg[i].value;
+            }
+
+            if (n == NGX_DECLINED) {
+                continue;
+            }
+
+            /* NGX_ERROR */
+
+            return NULL;
+        }
+    }
+
+#endif
+
+    return NULL;
+}
+
+
+#if (NGX_PCRE)
+
+static ngx_int_t
+ngx_stream_variable_not_found(ngx_stream_session_t *s,
+    ngx_stream_variable_value_t *v, uintptr_t data)
+{
+    v->not_found = 1;
+    return NGX_OK;
+}
+
+
+ngx_stream_regex_t *
+ngx_stream_regex_compile(ngx_conf_t *cf, ngx_regex_compile_t *rc)
+{
+    u_char                       *p;
+    size_t                        size;
+    ngx_str_t                     name;
+    ngx_uint_t                    i, n;
+    ngx_stream_variable_t        *v;
+    ngx_stream_regex_t           *re;
+    ngx_stream_regex_variable_t  *rv;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    rc->pool = cf->pool;
+
+    if (ngx_regex_compile(rc) != NGX_OK) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%V", &rc->err);
+        return NULL;
+    }
+
+    re = ngx_pcalloc(cf->pool, sizeof(ngx_stream_regex_t));
+    if (re == NULL) {
+        return NULL;
+    }
+
+    re->regex = rc->regex;
+    re->ncaptures = rc->captures;
+    re->name = rc->pattern;
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+    cmcf->ncaptures = ngx_max(cmcf->ncaptures, re->ncaptures);
+
+    n = (ngx_uint_t) rc->named_captures;
+
+    if (n == 0) {
+        return re;
+    }
+
+    rv = ngx_palloc(rc->pool, n * sizeof(ngx_stream_regex_variable_t));
+    if (rv == NULL) {
+        return NULL;
+    }
+
+    re->variables = rv;
+    re->nvariables = n;
+
+    size = rc->name_size;
+    p = rc->names;
+
+    for (i = 0; i < n; i++) {
+        rv[i].capture = 2 * ((p[0] << 8) + p[1]);
+
+        name.data = &p[2];
+        name.len = ngx_strlen(name.data);
+
+        v = ngx_stream_add_variable(cf, &name, NGX_STREAM_VAR_CHANGEABLE);
+        if (v == NULL) {
+            return NULL;
+        }
+
+        rv[i].index = ngx_stream_get_variable_index(cf, &name);
+        if (rv[i].index == NGX_ERROR) {
+            return NULL;
+        }
+
+        v->get_handler = ngx_stream_variable_not_found;
+
+        p += size;
+    }
+
+    return re;
+}
+
+
+ngx_int_t
+ngx_stream_regex_exec(ngx_stream_session_t *s, ngx_stream_regex_t *re,
+    ngx_str_t *str)
+{
+    ngx_int_t                     rc, index;
+    ngx_uint_t                    i, n, len;
+    ngx_stream_variable_value_t  *vv;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module);
+
+    if (re->ncaptures) {
+        len = cmcf->ncaptures;
+
+        if (s->captures == NULL) {
+            s->captures = ngx_palloc(s->connection->pool, len * sizeof(int));
+            if (s->captures == NULL) {
+                return NGX_ERROR;
+            }
+        }
+
+    } else {
+        len = 0;
+    }
+
+    rc = ngx_regex_exec(re->regex, str, s->captures, len);
+
+    if (rc == NGX_REGEX_NO_MATCHED) {
+        return NGX_DECLINED;
+    }
+
+    if (rc < 0) {
+        ngx_log_error(NGX_LOG_ALERT, s->connection->log, 0,
+                      ngx_regex_exec_n " failed: %i on \"%V\" using \"%V\"",
+                      rc, str, &re->name);
+        return NGX_ERROR;
+    }
+
+    for (i = 0; i < re->nvariables; i++) {
+
+        n = re->variables[i].capture;
+        index = re->variables[i].index;
+        vv = &s->variables[index];
+
+        vv->len = s->captures[n + 1] - s->captures[n];
+        vv->valid = 1;
+        vv->no_cacheable = 0;
+        vv->not_found = 0;
+        vv->data = &str->data[s->captures[n]];
+
+#if (NGX_DEBUG)
+        {
+        ngx_stream_variable_t  *v;
+
+        v = cmcf->variables.elts;
+
+        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
+                       "stream regex set $%V to \"%v\"", &v[index].name, vv);
+        }
+#endif
+    }
+
+    s->ncaptures = rc * 2;
+    s->captures_data = str->data;
+
+    return NGX_OK;
+}
+
+#endif
+
+
+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;
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    cmcf->variables_keys = ngx_pcalloc(cf->temp_pool,
+                                       sizeof(ngx_hash_keys_arrays_t));
+    if (cmcf->variables_keys == NULL) {
+        return NGX_ERROR;
+    }
+
+    cmcf->variables_keys->pool = cf->pool;
+    cmcf->variables_keys->temp_pool = cf->pool;
+
+    if (ngx_hash_keys_array_init(cmcf->variables_keys, NGX_HASH_SMALL)
+        != 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));
+        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;
+}
+
+
+ngx_int_t
+ngx_stream_variables_init_vars(ngx_conf_t *cf)
+{
+    ngx_uint_t                    i, n;
+    ngx_hash_key_t               *key;
+    ngx_hash_init_t               hash;
+    ngx_stream_variable_t        *v, *av;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    /* set the handlers for the indexed stream variables */
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    v = cmcf->variables.elts;
+    key = cmcf->variables_keys->keys.elts;
+
+    for (i = 0; i < cmcf->variables.nelts; i++) {
+
+        for (n = 0; n < cmcf->variables_keys->keys.nelts; n++) {
+
+            av = key[n].value;
+
+            if (v[i].name.len == key[n].key.len
+                && ngx_strncmp(v[i].name.data, key[n].key.data, v[i].name.len)
+                   == 0)
+            {
+                v[i].get_handler = av->get_handler;
+                v[i].data = av->data;
+
+                av->flags |= NGX_STREAM_VAR_INDEXED;
+                v[i].flags = av->flags;
+
+                av->index = i;
+
+                if (av->get_handler == NULL) {
+                    break;
+                }
+
+                goto next;
+            }
+        }
+
+        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                      "unknown \"%V\" variable", &v[i].name);
+
+        return NGX_ERROR;
+
+    next:
+        continue;
+    }
+
+
+    for (n = 0; n < cmcf->variables_keys->keys.nelts; n++) {
+        av = key[n].value;
+
+        if (av->flags & NGX_STREAM_VAR_NOHASH) {
+            key[n].key.data = NULL;
+        }
+    }
+
+
+    hash.hash = &cmcf->variables_hash;
+    hash.key = ngx_hash_key;
+    hash.max_size = cmcf->variables_hash_max_size;
+    hash.bucket_size = cmcf->variables_hash_bucket_size;
+    hash.name = "variables_hash";
+    hash.pool = cf->pool;
+    hash.temp_pool = NULL;
+
+    if (ngx_hash_init(&hash, cmcf->variables_keys->keys.elts,
+                      cmcf->variables_keys->keys.nelts)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    cmcf->variables_keys = NULL;
+
+    return NGX_OK;
+}