[CIFS] Reserve upcall IDX value for CIFS with connector header and add

Kconfig option for CIFS upcall.

Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/Kconfig

@@ -1680,6 +1680,18 @@ config CIFS_EXPERIMENTAL
 
 	    If unsure, say N.
 
+config CIFS_UPCALL
+	  bool "CIFS Kerberos/SPNEGO advanced session setup (EXPERIMENTAL)"
+	  depends on CIFS_EXPERIMENTAL
+	  select CONNECTOR
+	  help
+	    Enables an upcall mechanism for CIFS which will be used to contact
+	    userspace helper utilities to provide SPNEGO packaged Kerberos
+	    tickets which are needed to mount to certain secure servers
+	    (for which more secure Kerberos authentication is required).
+
+	  If unsure, say N.  
+
 config NCP_FS
 	tristate "NCP file system support (to mount NetWare volumes)"
 	depends on IPX!=n || INET

fs/cifs/connect.c

@@ -42,6 +42,7 @@
 #include "ntlmssp.h"
 #include "nterr.h"
 #include "rfc1002pdu.h"
+#include "cn_cifs.h"
 
 #define CIFS_PORT 445
 #define RFC1001_PORT 139

include/linux/connector.h

@@ -32,6 +32,8 @@
  */
 #define CN_IDX_PROC			0x1
 #define CN_VAL_PROC			0x1
+#define CN_IDX_CIFS			0x2
+#define CN_VAL_CIFS                     0x1
 
 #define CN_NETLINK_USERS		1