new file mode 100644
--- /dev/null
+++ b/src/core/ngx_resolver.c
@@ -0,0 +1,183 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+
+
+typedef struct {
+    ngx_connection_t      *connection;
+
+    struct sockaddr       *sockaddr;
+    socklen_t              socklen;
+
+    ngx_str_r              server;
+    ngx_str_r              name;
+
+    ngx_event_handler_pt   handler;
+
+    ngx_log_t             *pool;
+    ngx_log_t             *log;
+} ngx_resolver_t;
+
+
+ngx_int_t
+ngx_gethostbyname(ngx_resolver_t *r)
+{
+    ngx_socket_t  s;
+
+    if (r->connection) {
+        return NGX_OK;
+    }
+
+    s = ngx_socket(AF_INET, SOCK_DGRAM, 0);
+
+    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, r->log, 0, "socket %d", s);
+
+    if (s == -1) {
+        ngx_log_error(NGX_LOG_ALERT, r->log, ngx_socket_errno,
+                      ngx_socket_n " failed");
+        return NGX_ERROR;
+    }
+
+    c = ngx_get_connection(s, r->log);
+
+    if (c == NULL) {
+        if (ngx_close_socket(s) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, r->log, ngx_socket_errno,
+                          ngx_close_socket_n "failed");
+        }
+
+        return NGX_ERROR;
+    }
+
+    rev = c->read;
+    wev = c->write;
+
+    rev->log = pc->log;
+    wev->log = pc->log;
+
+    r->connection = c;
+
+    /*
+     * TODO: MT: - ngx_atomic_fetch_add()
+     *             or protection by critical section or mutex
+     *
+     * TODO: MP: - allocated in a shared memory
+     *           - ngx_atomic_fetch_add()
+     *             or protection by critical section or mutex
+     */
+
+    c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);
+
+#if (NGX_THREADS)
+    rev->lock = pc->lock;
+    wev->lock = pc->lock;
+    rev->own_lock = &c->lock;
+    wev->own_lock = &c->lock;
+#endif
+
+    ngx_log_debug3(NGX_LOG_DEBUG_EVENT, pc->log, 0,
+                   "connect to %V, fd:%d #%d", &r->server, s, c->number);
+
+    rc = connect(s, r->sockaddr, r->socklen);
+
+    if (rc == -1) {
+        ngx_log_error(level, r->log, ngx_socket_errno,
+                      "connect() to %V failed", &r->server);
+
+        return NGX_ERROR;
+    }
+
+
+
+
+
+
+
+    if (ngx_add_conn) {
+        if (ngx_add_conn(c) == NGX_ERROR) {
+            return NGX_ERROR;
+        }
+    }
+
+
+    if (ngx_add_conn) {
+        if (rc == -1) {
+
+            /* NGX_EINPROGRESS */
+
+            return NGX_AGAIN;
+        }
+
+        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, pc->log, 0, "connected");
+
+        wev->ready = 1;
+
+        return NGX_OK;
+    }
+
+    if (ngx_event_flags & NGX_USE_AIO_EVENT) {
+
+        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, pc->log, ngx_socket_errno,
+                       "connect(): %d", rc);
+
+        /* aio, iocp */
+
+        if (ngx_blocking(s) == -1) {
+            ngx_log_error(NGX_LOG_ALERT, pc->log, ngx_socket_errno,
+                          ngx_blocking_n " failed");
+            return NGX_ERROR;
+        }
+
+        /*
+         * FreeBSD's aio allows to post an operation on non-connected socket.
+         * NT does not support it.
+         *
+         * TODO: check in Win32, etc. As workaround we can use NGX_ONESHOT_EVENT
+         */
+
+        rev->ready = 1;
+        wev->ready = 1;
+
+        return NGX_OK;
+    }
+
+    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {
+
+        /* kqueue */
+
+        event = NGX_CLEAR_EVENT;
+
+    } else {
+
+        /* select, poll, /dev/poll */
+
+        event = NGX_LEVEL_EVENT;
+    }
+
+    if (ngx_add_event(rev, NGX_READ_EVENT, event) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    if (rc == -1) {
+
+        /* NGX_EINPROGRESS */
+
+        if (ngx_add_event(wev, NGX_WRITE_EVENT, event) != NGX_OK) {
+            return NGX_ERROR;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    ngx_log_debug0(NGX_LOG_DEBUG_EVENT, pc->log, 0, "connected");
+
+    wev->ready = 1;
+
+    return NGX_OK;
+}