Campus-25/static/Servers/Tachyon/deploy/DEPLOY.md

Deploying Tachyon voice with Campus

Tachyon is a standalone C++ UDP voice server that runs alongside the Campus C# server on the Linux VPS. Voice is proximity/room-scoped: Tachyon relays Dissonance voice and asks the C# server which room each speaker is in. No client patch is needed (plaintext 0x11 path).

The C# server changes are already in the repo (see "What the C# side does" below) and are config-gated OFF by default — until you set TachyonVoiceEndpoint, clients keep using the existing Photon Voice P2P path, so nothing about voice changes until you flip it on.

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1. Build Tachyon on the VPS

Needs: git, CMake ≥ 3.16, a C++23 compiler (gcc 13+/clang 16+), libcurl-devel, openssl-devel. (Debian/Ubuntu: libcurl4-openssl-dev libssl-dev.)

sudo mkdir -p /opt/tachyon && sudo chown "$USER" /opt/tachyon
git clone <this repo> /opt/tachyon
cd /opt/tachyon
git submodule update --init --recursive        # LiteNetLibPP is a pinned submodule
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

The configure step applies patches/0001-tachyon-packet-layer-hook.patch to the submodule, so vendor/LiteNetLibPP shows as "dirty" afterward — that is expected.

Smoke-test the binary offline (no network):

./build/tachyon --selftest        # exit 0 = pass

2. Config

tachyon.conf (repo root) is ready to use. Key line:

room_url = https://camprec.net/tachyon

Tachyon calls GET <room_url>?id=<AccountId> and expects a bare roomInstanceId. If Tachyon and the C# server are on the same box and you know Kestrel's local port, you can change this to http://127.0.0.1:<port>/tachyon to skip the public round-trip. Copy the file to /opt/tachyon if you cloned elsewhere.

3. Firewall — open UDP 7777

Clients connect over UDP, not TCP. Whatever the C# server's HTTPS uses, voice needs 7777/udp open to the internet:

sudo ufw allow 7777/udp            # or the cloud provider's security-group equivalent

If the VPS is behind a NAT/provider firewall, forward/allow 7777/udp to this host too.

4. Run as a service

sudo cp deploy/tachyon.service /etc/systemd/system/tachyon.service
# edit paths in the unit if you did not use /opt/tachyon
sudo systemctl daemon-reload
sudo systemctl enable --now tachyon
journalctl -u tachyon -f           # watch it; -v in the conf for per-relay detail

5. Flip voice over to Tachyon (C# side)

In ConfigCampus.cs set the endpoint the CLIENT will dial (public IP or DDNS host + Tachyon's port — not 127.0.0.1, the client is remote):

public static string TachyonVoiceEndpoint = "camprec.net:7777";

Rebuild + redeploy the C# server. From then on /Matchmaking/player/connection-info hands the client voiceConnectionInfo = "camprec.net:7777" and a non-empty voiceServerId, so it routes voice through Tachyon. To roll back to Photon P2P instantly, set it back to "".

6. Verify

• journalctl -u tachyon -f shows a handshake and account=… senderId=… relay lines when two players are in the same room and talking.
• Two clients in the same room hear each other; two in different rooms do not (room scoping via /tachyon). A lookup failure isolates a client (fail-safe: they hear no one).
• curl "https://camprec.net/tachyon?id=<someOnlineAccountId>" returns that player's numeric room instance id (or 0 if they're nowhere).

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What the C# side does (already committed)

File	Change
Controllers/TachyonController.cs	New. GET /tachyon?id=<AccountId> → bare roomInstanceId (text/plain), via HeartbeatDB.PeekPresence. 0 when unknown/offline (fail-safe).
Controllers/MatchmakingController.cs	player/connection-info now sets voiceConnectionInfo/voiceServerId from config (empty ⇒ Photon fallback).
api/server/ConfigCampus.cs	TachyonVoiceEndpoint (default "") + TachyonVoiceServerId.
Middleware/PatchGateMiddleware.cs	/tachyon added to the no-patch-header open list (server-to-server).

Notes / caveats

• Plaintext voice only (0x11); no private_key is set and none is needed. The encrypted 0x2A path would need KT minting + the transport cipher confirmed first — out of scope.
• The room lookup is synchronous on Tachyon's handshake path (blocks up to room_timeout_ms). Fine for normal joins; revisit only if join storms matter.
• voiceServerId is just a stable client-side label — Tachyon's protocol has no room/server id on the wire; room scoping is entirely via the /tachyon lookup.