Secure networking infrastructure for Atari 8-bit emulators. Telnet BBS access, TNFS file servers, and multiplayer netplay — all over encrypted transports.
Fuji-Services is a secure, multiplexed session protocol (FSSP) designed to transport legacy and modern protocols unchanged over encrypted connections. It enables Atari emulators to access BBS systems, remote file servers, and multiplayer sessions without exposing raw network traffic.
The protocol is transport-agnostic — it runs over WebSocket/TLS on port 443, making it NAT-friendly and firewall-safe. Legacy protocols like Telnet and TNFS travel inside encrypted FSSP channels, preserving their original behavior while adding security, authentication, and multiplexing.
Three components connect retro systems to modern services.
Local endpoint near the emulator or retro system. Opens FSSP sessions and maps local protocols to channels.
Remote endpoint near target services. Terminates FSSP sessions and connects channels to BBS, TNFS, or game servers.
Optional neutral router for NAT traversal. Forwards encrypted frames between Bridge and Edge without inspecting payloads.
FSSP multiplexes multiple protocol streams over a single session.
| Type | ID | Behavior | Use Cases |
|---|---|---|---|
| CONTROL | 0x00 | Session control plane | Capabilities negotiation, channel open/close, errors |
| DATAGRAM | 0x01 | Unordered, best effort | TNFS file access, service discovery |
| STREAM | 0x02 | Ordered, reliable | Telnet BBS, serial COM streams |
| INPUT | 0x03 | Prioritized delivery | Joystick and keyboard input for netplay |
| VIDEO | 0x04 | Optional streaming | Framebuffer streaming, spectator mode |
16 reserved channel IDs for common use cases.
| Channel | Purpose | Type |
|---|---|---|
| 0 | Control Plane | CONTROL |
| 1 | Telnet / BBS | STREAM |
| 2 – 3 | Modem / COM A & B | STREAM |
| 4 – 5 | TNFS / UDP A & B | DATAGRAM |
| 6 – 9 | Joystick P1 – P4 | INPUT |
| 10 | Keyboard | INPUT |
| 11 | Video Primary | VIDEO |
| 12 | Video Secondary / Spectator | VIDEO |
| 13 – 15 | Reserved / Plugin Lanes | Any |
Connect to Atari BBS systems over encrypted Telnet. The STREAM channel carries raw Telnet bytes while FSSP handles TLS encryption and authentication.
Access remote disk images and software libraries via TNFS, tunneled through DATAGRAM channels. Compatible with FujiNet and other TNFS clients.
Connect emulated machines for multiplayer gaming. INPUT channels deliver joystick and keyboard events with priority scheduling for low-latency gameplay.
FSSP is secure by default. All sessions require TLS 1.3 encryption. Authentication uses bearer tokens with short-lived credentials recommended. The relay never sees plaintext payloads — it forwards encrypted frames without inspection.
FSSP is at version 0.1-draft. The protocol specification is complete but reference implementations have not yet begun. The protocol is designed to be implemented in Go (Bridge, Edge, Relay) with a Swift client integration for Fuji emulators.
The full specification is available in the project repository.
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