| NetLabel Introduction | 
 | ============================================================================== | 
 | Paul Moore, paul.moore@hp.com | 
 |  | 
 | August 2, 2006 | 
 |  | 
 |  * Overview | 
 |  | 
 | NetLabel is a mechanism which can be used by kernel security modules to attach | 
 | security attributes to outgoing network packets generated from user space | 
 | applications and read security attributes from incoming network packets.  It | 
 | is composed of three main components, the protocol engines, the communication | 
 | layer, and the kernel security module API. | 
 |  | 
 |  * Protocol Engines | 
 |  | 
 | The protocol engines are responsible for both applying and retrieving the | 
 | network packet's security attributes.  If any translation between the network | 
 | security attributes and those on the host are required then the protocol | 
 | engine will handle those tasks as well.  Other kernel subsystems should | 
 | refrain from calling the protocol engines directly, instead they should use | 
 | the NetLabel kernel security module API described below. | 
 |  | 
 | Detailed information about each NetLabel protocol engine can be found in this | 
 | directory, consult '00-INDEX' for filenames. | 
 |  | 
 |  * Communication Layer | 
 |  | 
 | The communication layer exists to allow NetLabel configuration and monitoring | 
 | from user space.  The NetLabel communication layer uses a message based | 
 | protocol built on top of the Generic NETLINK transport mechanism.  The exact | 
 | formatting of these NetLabel messages as well as the Generic NETLINK family | 
 | names can be found in the the 'net/netlabel/' directory as comments in the | 
 | header files as well as in 'include/net/netlabel.h'. | 
 |  | 
 |  * Security Module API | 
 |  | 
 | The purpose of the NetLabel security module API is to provide a protocol | 
 | independent interface to the underlying NetLabel protocol engines.  In addition | 
 | to protocol independence, the security module API is designed to be completely | 
 | LSM independent which should allow multiple LSMs to leverage the same code | 
 | base. | 
 |  | 
 | Detailed information about the NetLabel security module API can be found in the | 
 | 'include/net/netlabel.h' header file as well as the 'lsm_interface.txt' file | 
 | found in this directory. |