new file mode 100644
--- /dev/null
+++ b/src/http/modules/ngx_http_map_module.c
@@ -0,0 +1,637 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+#define NGX_HTTP_MAP_HASH       10007
+
+typedef struct {
+    ngx_uint_t                  hash_max_size;
+    ngx_uint_t                  hash_bucket_size;
+} ngx_http_map_conf_t;
+
+
+typedef struct {
+    ngx_pool_t                 *pool;
+
+    ngx_array_t                 keys;
+    ngx_array_t                *keys_hash;
+
+    ngx_array_t                 dns_wildcards;
+    ngx_array_t                *dns_hash;
+
+    ngx_array_t                *values_hash;
+
+    ngx_http_variable_value_t  *default_value;
+    ngx_uint_t                  hostnames;      /* unsigned  hostnames:1 */
+} ngx_http_map_conf_ctx_t;
+
+
+typedef struct {
+    ngx_hash_t                  hash;
+    ngx_hash_wildcard_t        *dns_wildcards;
+    ngx_int_t                   index;
+    ngx_http_variable_value_t  *default_value;
+    ngx_uint_t                  hostnames;      /* unsigned  hostnames:1 */
+} ngx_http_map_ctx_t;
+
+
+static int ngx_libc_cdecl ngx_http_map_cmp_dns_wildcards(const void *one,
+    const void *two);
+static void *ngx_http_map_create_conf(ngx_conf_t *cf);
+static char *ngx_http_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
+static char *ngx_http_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf);
+
+
+static ngx_command_t  ngx_http_map_commands[] = {
+
+    { ngx_string("map"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2,
+      ngx_http_map_block,
+      NGX_HTTP_MAIN_CONF_OFFSET,
+      0,
+      NULL },
+
+    { ngx_string("map_hash_max_size"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_MAIN_CONF_OFFSET,
+      offsetof(ngx_http_map_conf_t, hash_max_size),
+      NULL },
+
+    { ngx_string("map_hash_bucket_size"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_MAIN_CONF_OFFSET,
+      offsetof(ngx_http_map_conf_t, hash_bucket_size),
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_map_module_ctx = {
+    NULL,                                  /* preconfiguration */
+    NULL,                                  /* postconfiguration */
+
+    ngx_http_map_create_conf,              /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    NULL,                                  /* create server configuration */
+    NULL,                                  /* merge server configuration */
+
+    NULL,                                  /* create location configuration */
+    NULL                                   /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_map_module = {
+    NGX_MODULE_V1,
+    &ngx_http_map_module_ctx,              /* module context */
+    ngx_http_map_commands,                 /* module directives */
+    NGX_HTTP_MODULE,                       /* module type */
+    NULL,                                  /* init master */
+    NULL,                                  /* init module */
+    NULL,                                  /* init process */
+    NULL,                                  /* init thread */
+    NULL,                                  /* exit thread */
+    NULL,                                  /* exit process */
+    NULL,                                  /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static ngx_int_t
+ngx_http_map_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
+    uintptr_t data)
+{
+    ngx_http_map_ctx_t  *map = (ngx_http_map_ctx_t *) data;
+
+    size_t                      len;
+    u_char                     *name;
+    ngx_uint_t                  key, i;
+    ngx_http_variable_value_t  *vv, *value;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http map started");
+
+    vv = ngx_http_get_flushed_variable(r, map->index);
+
+    len = vv->len;
+
+    if (len && map->hostnames && vv->data[len - 1] == '.') {
+        len--;
+    }
+
+    if (len == 0) {
+        *v = *map->default_value;
+        return NGX_OK;
+    }
+
+    name = ngx_palloc(r->pool, len);
+    if (name == NULL) {
+        return NGX_ERROR;
+    }
+
+    key = 0;
+    for (i = 0; i < len; i++) {
+        name[i] = ngx_tolower(vv->data[i]);
+        key = ngx_hash(key, name[i]);
+    }
+
+    value = NULL;
+
+    if (map->hash.buckets) {
+        value = ngx_hash_find(&map->hash, key, name, len);
+    }
+
+    if (value) {
+        *v = *value;
+
+    } else {
+        if (map->dns_wildcards && map->dns_wildcards->hash.buckets) {
+            value = ngx_hash_find_wildcard(map->dns_wildcards, name, len);
+            if (value) {
+                *v = *value;
+
+            } else {
+                *v = *map->default_value;
+            }
+
+        } else {
+            *v = *map->default_value;
+        }
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http map: \"%V\" \"%V\"", vv, v);
+
+    return NGX_OK;
+}
+
+
+static void *
+ngx_http_map_create_conf(ngx_conf_t *cf)
+{
+    ngx_http_map_conf_t  *mcf;
+
+    mcf = ngx_palloc(cf->pool, sizeof(ngx_http_map_conf_t));
+    if (mcf == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    mcf->hash_max_size = NGX_CONF_UNSET_UINT;
+    mcf->hash_bucket_size = NGX_CONF_UNSET_UINT;
+
+    return mcf;
+}
+
+
+static char *
+ngx_http_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_map_conf_t  *mcf = conf;
+
+    char                      *rv;
+    ngx_str_t                 *value, name;
+    ngx_conf_t                 save;
+    ngx_pool_t                *pool;
+    ngx_hash_init_t            hash;
+    ngx_http_map_ctx_t        *map;
+    ngx_http_variable_t       *var;
+    ngx_http_map_conf_ctx_t    ctx;
+
+    if (mcf->hash_max_size == NGX_CONF_UNSET_UINT) {
+        mcf->hash_max_size = 2048;
+    }
+
+    if (mcf->hash_bucket_size == NGX_CONF_UNSET_UINT) {
+        mcf->hash_bucket_size = ngx_cacheline_size;
+
+    } else {
+        mcf->hash_bucket_size = ngx_align(mcf->hash_bucket_size,
+                                          ngx_cacheline_size);
+    }
+
+    map = ngx_pcalloc(cf->pool, sizeof(ngx_http_map_ctx_t));
+    if (map == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    value = cf->args->elts;
+
+    name = value[1];
+    name.len--;
+    name.data++;
+
+    map->index = ngx_http_get_variable_index(cf, &name);
+
+    if (map->index == NGX_ERROR) {
+        return NGX_CONF_ERROR;
+    }
+
+    name = value[2];
+    name.len--;
+    name.data++;
+
+    var = ngx_http_add_variable(cf, &name, NGX_HTTP_VAR_CHANGABLE);
+    if (var == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    var->handler = ngx_http_map_variable;
+    var->data = (uintptr_t) map;
+
+    pool = ngx_create_pool(16384, cf->log);
+    if (pool == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_array_init(&ctx.keys, pool, 16384, sizeof(ngx_hash_key_t))
+        != NGX_OK)
+    {
+        ngx_destroy_pool(pool);
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_array_init(&ctx.dns_wildcards, pool, 16384, sizeof(ngx_hash_key_t))
+        != NGX_OK)
+    {
+        ngx_destroy_pool(pool);
+        return NGX_CONF_ERROR;
+    }
+
+    ctx.keys_hash = ngx_pcalloc(pool, sizeof(ngx_array_t) * NGX_HTTP_MAP_HASH);
+    if (ctx.keys_hash == NULL) {
+        ngx_destroy_pool(pool);
+        return NGX_CONF_ERROR;
+    }
+
+    ctx.dns_hash = ngx_pcalloc(pool, sizeof(ngx_array_t) * NGX_HTTP_MAP_HASH);
+    if (ctx.dns_hash == NULL) {
+        ngx_destroy_pool(pool);
+        return NGX_CONF_ERROR;
+    }
+
+    ctx.values_hash = ngx_pcalloc(pool,
+                                  sizeof(ngx_array_t) * NGX_HTTP_MAP_HASH);
+    if (ctx.values_hash == NULL) {
+        ngx_destroy_pool(pool);
+        return NGX_CONF_ERROR;
+    }
+
+    ctx.pool = cf->pool;
+    ctx.default_value = NULL;
+    ctx.hostnames = 0;
+
+    save = *cf;
+    cf->pool = pool;
+    cf->ctx = &ctx;
+    cf->handler = ngx_http_map;
+    cf->handler_conf = conf;
+
+    rv = ngx_conf_parse(cf, NULL);
+
+    *cf = save;
+
+    if (rv != NGX_CONF_OK) {
+        ngx_destroy_pool(pool);
+
+        return rv;
+    }
+
+    hash.key = ngx_hash_key_lc;
+    hash.max_size = mcf->hash_max_size;
+    hash.bucket_size = mcf->hash_bucket_size;
+    hash.name = "map_hash";
+    hash.pool = cf->pool;
+
+    if (ctx.keys.nelts) {
+        hash.hash = &map->hash;
+        hash.temp_pool = NULL;
+
+        if (ngx_hash_init(&hash, ctx.keys.elts, ctx.keys.nelts) != NGX_OK) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+    map->default_value = ctx.default_value ? ctx.default_value:
+                                             &ngx_http_variable_null_value;
+
+    if (ctx.dns_wildcards.nelts) {
+
+        ngx_qsort(ctx.dns_wildcards.elts, (size_t) ctx.dns_wildcards.nelts,
+                  sizeof(ngx_hash_key_t), ngx_http_map_cmp_dns_wildcards);
+
+        hash.hash = NULL;
+        hash.temp_pool = pool;
+
+        if (ngx_hash_wildcard_init(&hash, ctx.dns_wildcards.elts,
+                                   ctx.dns_wildcards.nelts)
+            != NGX_OK)
+        {
+            return NGX_CONF_ERROR;
+        }
+
+        map->dns_wildcards = (ngx_hash_wildcard_t *) hash.hash;
+    }
+
+    ngx_destroy_pool(pool);
+
+    return rv;
+}
+
+
+static int ngx_libc_cdecl
+ngx_http_map_cmp_dns_wildcards(const void *one, const void *two)
+{
+    ngx_hash_key_t  *first, *second;
+
+    first = (ngx_hash_key_t *) one;
+    second = (ngx_hash_key_t *) two;
+
+    return ngx_strcmp(first->key.data, second->key.data);
+}
+
+
+static char *
+ngx_http_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
+{
+    size_t                      len;
+    ngx_str_t                  *value, file, *name;
+    ngx_uint_t                  i, n, key;
+    ngx_hash_key_t             *m;
+    ngx_http_map_conf_ctx_t    *ctx;
+    ngx_http_variable_value_t  *var, *old, **vp;
+    u_char                      buf[2048];
+
+    ctx = cf->ctx;
+
+    value = cf->args->elts;
+
+    if (cf->args->nelts == 1
+        && ngx_strcmp(value[0].data, "hostnames") == 0)
+    {
+        ctx->hostnames = 1;
+        return NGX_CONF_OK;
+
+    } else if (cf->args->nelts != 2) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid number of the map parameters");
+        return NGX_CONF_ERROR;
+
+    } else if (value[0].len == 0) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                           "invalid first parameter");
+        return NGX_CONF_ERROR;
+    }
+
+    if (ngx_strcmp(value[0].data, "include") == 0) {
+        file = value[1];
+
+        if (ngx_conf_full_name(cf->cycle, &file) == NGX_ERROR){
+            return NGX_CONF_ERROR;
+        }
+
+        ngx_log_debug1(NGX_LOG_DEBUG_CORE, cf->log, 0, "include %s", file.data);
+
+        return ngx_conf_parse(cf, &file);
+    }
+
+    key = 0;
+
+    for (i = 0; i < value[1].len; i++) {
+        key = ngx_hash(key, value[1].data[i]);
+    }
+
+    key %= NGX_HTTP_MAP_HASH;
+
+    vp = ctx->values_hash[key].elts;
+
+    if (vp) {
+        for (i = 0; i < ctx->values_hash[key].nelts; i++) {
+            if (value[1].len != (size_t) vp[i]->len) {
+                continue;
+            }
+
+            if (ngx_strncmp(value[1].data, vp[i]->data, value[1].len) == 0) {
+                var = vp[i];
+                goto found;
+            }
+        }
+
+    } else {
+        if (ngx_array_init(&ctx->values_hash[key], cf->pool, 4,
+                           sizeof(ngx_http_variable_value_t *))
+            != NGX_OK)
+        {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+    var = ngx_palloc(ctx->pool, sizeof(ngx_http_variable_value_t));
+    if (var == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    var->len = value[1].len;
+    var->data = ngx_pstrdup(ctx->pool, &value[1]);
+    if (var->data == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    var->valid = 1;
+    var->no_cachable = 0;
+    var->not_found = 0;
+
+    vp = ngx_array_push(&ctx->values_hash[key]);
+    if (vp == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    *vp = var;
+
+found:
+
+    if (value[0].data[0] != '*' || ctx->hostnames == 0) {
+
+        if (ngx_strcmp(value[0].data, "default") != 0) {
+
+            if (value[0].len && value[0].data[0] == '!') {
+                value[0].len--;
+                value[0].data++;
+            }
+
+            key = 0;
+
+            for (i = 0; i < value[0].len; i++) {
+                value[0].data[i] = ngx_tolower(value[0].data[i]);
+                key = ngx_hash(key, value[0].data[i]);
+            }
+
+            key %= NGX_HTTP_MAP_HASH;
+
+            name = ctx->keys_hash[key].elts;
+
+            if (name) {
+                for (i = 0; i < ctx->keys_hash[key].nelts; i++) {
+                    if (value[0].len != name[i].len) {
+                        continue;
+                    }
+
+                    if (ngx_strncmp(value[0].data, name[i].data, value[0].len)
+                        == 0)
+                    {
+                        m = ctx->keys.elts;
+                        for (i = 0; i < ctx->keys.nelts; i++) {
+                            if (ngx_strcmp(value[0].data, m[i].key.data) == 0) {
+                                old = m[i].value;
+                                m[i].value = var;
+
+                                goto duplicate;
+                            }
+                        }
+                    }
+                }
+
+            } else {
+                if (ngx_array_init(&ctx->keys_hash[key], cf->pool, 4,
+                                   sizeof(ngx_str_t))
+                    != NGX_OK)
+                {
+                    return NGX_CONF_ERROR;
+                }
+            }
+
+            name = ngx_array_push(&ctx->keys_hash[key]);
+            if (name == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            *name = value[0];
+
+            m = ngx_array_push(&ctx->keys);
+            if (m == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            m->key = value[0];
+            m->key_hash = ngx_hash_key(value[0].data, value[0].len);
+            m->value = var;
+
+        } else {
+            if (ctx->default_value) {
+                old = ctx->default_value;
+                ctx->default_value = var;
+
+                goto duplicate;
+            }
+
+            ctx->default_value = var;
+        }
+
+    } else {
+
+        if (value[0].len < 3 || value[0].data[1] != '.') {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "invalid DNS wildcard \"%V\"", &value[0]);
+            return NGX_CONF_ERROR;
+        }
+
+        key = 0;
+
+        for (i = 2; i < value[0].len; i++) {
+            value[0].data[i] = ngx_tolower(value[0].data[i]);
+            key = ngx_hash(key, value[0].data[i]);
+        }
+
+        key %= NGX_HTTP_MAP_HASH;
+
+        /* convert "*.example.com" into "com.example.\0" */
+
+        len = 0;
+        n = 0;
+
+        for (i = value[0].len - 1; i; i--) {
+            if (value[0].data[i] == '.') {
+                ngx_memcpy(&buf[n], &value[0].data[i + 1], len);
+                n += len;
+                buf[n++] = '.';
+                len = 0;
+                continue;
+            }
+
+            len++;
+        }
+
+        buf[n] = '\0';
+
+        name = ctx->dns_hash[key].elts;
+
+        if (name) {
+            for (i = 0; i < ctx->dns_hash[key].nelts; i++) {
+                if (value[0].len != name[i].len) {
+                    continue;
+                }
+
+                if (ngx_strncmp(value[0].data, name[i].data, value[0].len)
+                    == 0)
+                {
+                    m = ctx->dns_wildcards.elts;
+                    for (i = 0; i < ctx->dns_wildcards.nelts; i++) {
+                        if (ngx_strcmp(buf, m[i].key.data) == 0) {
+                            old = m[i].value;
+                            m[i].value = var;
+
+                            goto duplicate;
+                        }
+                    }
+                }
+            }
+
+        } else {
+            if (ngx_array_init(&ctx->dns_hash[key], cf->pool, 4,
+                               sizeof(ngx_str_t))
+                != NGX_OK)
+            {
+                return NGX_CONF_ERROR;
+            }
+        }
+
+        name = ngx_array_push(&ctx->dns_hash[key]);
+        if (name == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        *name = value[0];
+
+        ngx_memcpy(value[0].data, buf, value[0].len);
+        value[0].len--;
+
+        m = ngx_array_push(&ctx->dns_wildcards);
+        if (m == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        m->key = value[0];
+        m->key_hash = 0;
+        m->value = var;
+    }
+
+    return NGX_CONF_OK;
+
+duplicate:
+
+    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+                       "duplicate parameter \"%V\", value: \"%V\", "
+                       "old value: \"%V\"",
+                       &value[0], var, old);
+
+    return NGX_CONF_OK;
+}