Overview: IPC message structure

In KasperskyOS, all interactions between processes have statically defined types. The permissible structures of an IPC message are defined by the description of the interfaces of the process that receives the message (server).

A correct IPC message (request and response) contains a constant part and an arena.

Constant part of a message

The constant part of a message contains arguments of a fixed size, and the RIID and MID.

Fixed-size arguments can be arguments of any IDL types except the sequence type.

The RIID and MID identify the interface and method being called:

• The RIID (Runtime Implementation ID) is the number of the process endpoint being called, starting at zero.
• The MID (Method ID) is the number of the method within the interface that contains it, starting at zero.

The type of the constant part of the message is generated by the NK compiler based on the IDL description of the interface. A separate structure is generated for each interface method. Union types are also generated for storing any request to a process, component or interface. For more details, refer to Example generation of transport methods and types.

Arena

The arena is a buffer for storing variable-size arguments (sequence IDL type).

Message structure verification by the security module

Prior to calling message-related rules, the Kaspersky Security Module verifies that the sent message is correct. Requests and responses are both validated. If the message has an incorrect structure, it will be rejected without calling the security model methods associated with it.

Forming a message structure

KasperskyOS Community Edition includes the following tools that make it easier for the developer to create and package an IPC message:

• The transport-kos library for working with NkKosTransport.
• The NK compiler that lets you generate special methods and types.

Simple IPC message generation is demonstrated in the echo and ping examples (/opt/KasperskyOS-Community-Edition-<version>/examples/).