openprot-spdm-transport-mctp

MCTP transport layer for SPDM protocol communication.

Overview

This crate implements the SpdmTransport trait from spdm-lib using MCTP as the underlying transport mechanism. It bridges the SPDM protocol layer with the MCTP messaging infrastructure.

MCTP Binding

• Message Type: 0x05 (SPDM, per DMTF DSP0236 §4.2.1)
• Max Message Size: 2048 bytes
• Fragmentation: Handled by MCTP layer
• Tag Correlation: MCTP tags used for request/response matching

Modes

Requester Mode

Used by SPDM requesters (clients) that initiate attestation operations:

let transport = MctpSpdmTransport::new_requester(mctp_client, remote_eid);

Responder Mode

Used by SPDM responders (servers) that handle attestation requests:

let transport = MctpSpdmTransport::new_responder(mctp_client);

Transport Lifecycle

1. Initialize: init_sequence() establishes MCTP handles

   • Requester: Creates request handle to remote EID
   • Responder: Registers listener for SPDM messages

2. Communication:

   • Requester: send_request() → receive_response()
   • Responder: receive_request() → send_response()

3. Cleanup: Automatically releases MCTP handles on drop

Dependencies

• openprot-mctp-api — MCTP client trait and types
• spdm-lib — SPDM protocol library with transport trait

Usage

This crate is used by both:

• openprot-spdm-requester — SPDM client implementation
• openprot-spdm-responder — SPDM server implementation