The RDBSS Driver and Library

The Redirected Drive Buffering Subsystem (RDBSS) is implemented in two forms:

• A file system driver (rdbss.sys) supplied with the operating system.

• A static library (rdbsslib.lib) supplied with the Windows Driver Kit (WDK).

The rdbss.sys driver is automatically loaded if any non-monolithic network mini-redirectors are registered on the system. The Microsoft Server Message Block (SMB) redirector (mrxsmb sys) is currently the only driver that can be built as a non-monolithic network mini-redirector driver.

All other network mini-redirector drivers, including other Microsoft network mini-redirectors supplied with the operating system, must be implemented as monolithic drivers that link with the rdbsslib.lib static library provided with the WDK.

The RDBSS uses a well-defined mechanism for communication with network mini-redirector drivers, I/O Manager, Cache Manager, Memory Manager, and other kernel systems.

RDBSS exports a large number of routines that can be called by a network mini-redirector and other kernel systems to set options and perform various operations. To call the routines exported by RDBSS, a network mini-redirector driver (or other kernel driver) includes the appropriate WDK header files, calls the exported RDBSS routine by name, and links with the appropriate rdbsslib.lib file installed with the WDK. Note that different rdbsslib.lib files are provided with the WDK for Window Vista, Windows Server 2003, Windows XP, and Windows 2000.

The WDK header files for RDBSS also define a number of macros that are recommended for use by network mini-redirector drivers, rather than calling some of the RDBSS routines directly.

All of the data structures defined and used by RDBSS have a special 4-byte signature at the beginning of the data structure that is used extensively in validation. The values for these RDBSS data structures signatures are defined in the WDK header file, nodetype.h. These data structure signatures are used for troubleshooting and debugging RDBSS and network mini-redirector drivers.

The following sections discuss in detail each of the categories of routines exported by RDBSS and the macros defined to call these routines. We begin with a list of all of the routines provided by RDBSS and a similar list of macros defined by RDBSS:

• Routines Provided by RDBSS

• Macros Defined by RDBSS

The routines exported by RDBSS and the RDBSS macros defined to call these routines can be organized into a number of different categories, including the following:

• Driver Registration and Start/Stop Control

• Pool Allocation and Free Routines

• Timer and Worker Thread Management

• Work Queue Dispatching Mechanisms

• Diagnostics and Debugging

• Logging Routines and Macros

• Miscellaneous Routines

• RX_CONTEXT and IRP Management

• Connection and File Structure Management

• FCB Resource Synchronization

• Buffering State Control

• Low I/O Routines

• Name Cache Management

• Prefix Table Management

• Purging and Scavenging Control

• Multiplex ID Management

• Connection Engine Management