Implemented server framework for asynchronous IO on sockets.

diff --git a/server/protocol.def b/server/protocol.def
index e151470..e75373e 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -610,9 +610,10 @@
     FD_TYPE_CONSOLE,
     FD_TYPE_SMB
 };
-#define FD_FLAG_OVERLAPPED 0x01
-#define FD_FLAG_TIMEOUT    0x02
-
+#define FD_FLAG_OVERLAPPED         0x01
+#define FD_FLAG_TIMEOUT            0x02
+#define FD_FLAG_RECV_SHUTDOWN      0x04
+#define FD_FLAG_SEND_SHUTDOWN      0x08
 
 /* Set a file current position */
 @REQ(set_file_pointer)