# Commonwealth Online Dedicated Server

The dedicated server is implemented in C# on .NET 8. Valve GameNetworkingSockets remains in the native C++ bridge under `native_transport/`, and the C# server loads its C ABI directly.

## Run

Packaged Windows:

```bat
CommonwealthOnline.Server.exe serve --config commonwealth-server.json
```

Packaged Linux:

```bash
./CommonwealthOnline.Server serve --config commonwealth-server.json
```

Source checkout:

```bash
dotnet build CommonwealthOnline.Server.csproj -c Release
dotnet run --project tests/CommonwealthOnline.Server.Tests.csproj -c Release
dotnet run --project CommonwealthOnline.Server.csproj -- serve --config commonwealth-server.json --interactive
```

`start.bat` and `start.sh` prefer a published apphost, then a framework-dependent DLL, then `dotnet run` in a source checkout.

## Config

Generate defaults:

```bash
dotnet run --project CommonwealthOnline.Server.csproj -- config init commonwealth-server.json
```

Existing field names remain supported:

```json
{
  "host": "0.0.0.0",
  "port": 7777,
  "server_name": "Commonwealth Online Server",
  "server_description": "",
  "max_players": 16,
  "log_verbosity": "info",
  "admin_port": 7779,
  "enable_gns_transport": false,
  "gns_bridge_path": null
}
```

When GNS is enabled, `host` must be an explicit IPv4 bind address. TCP and GNS may use the same numeric game port because they use TCP and UDP separately.

## Ports

- TCP 7777 by default: gameplay compatibility
- UDP 7777 by default: GNS gameplay when enabled
- UDP 7778: LAN discovery
- TCP 127.0.0.1:7779 by default: authenticated administration

## Admin CLI

```bash
dotnet run --project CommonwealthOnline.Server.csproj -- status --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- clients --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- kick 2 --reason griefing --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- ban 2 --reason griefing --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- unban 192.0.2.5 --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- bans --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- world time 1430 --config commonwealth-server.json
dotnet run --project CommonwealthOnline.Server.csproj -- world weather 0002b52a --config commonwealth-server.json
```

The admin channel authenticates with `.admin-token` beside the config file and binds to localhost only.

## Load test

The C# synthetic Protocol V2 client provides deterministic multi-client load coverage:

```bash
dotnet run --project CommonwealthOnline.Server.csproj -- load-test --host 127.0.0.1 --port 7777 --clients 16
```

## Architecture

C# owns:

- Protocol V2 decoding/validation
- session admission and server-owned player IDs
- movement validation and corrections
- cell/worldspace interest filtering
- durable player state
- scoped NPC authority and epochs
- combat routing
- world state
- bans and rate limits
- handshake and idle timeouts
- TCP compatibility
- GNS sequencing/envelope handling
- LAN discovery
- admin control

C++ owns only the Valve GNS transport bridge:

- initialization/shutdown
- UDP listen socket
- GNS connection lifecycle
- message polling/sending
- disconnects
- remote endpoint lookup

## Protocol guarantees

- Maximum message size remains 64 KiB.
- `transform` and `npcState` are unreliable/sequenced under GNS.
- Reliable gameplay/control packets remain reliable/ordered.
- Snapshot sequences are wrap-safe; stale and duplicate snapshots are rejected.
- Server-owned identity is applied before mutation/relay.
- Movement validation runs before transform mutation/relay.
- Interest filtering remains authoritative.
- NPC authority is scoped by cell/worldspace and epoch.
- Durable player state is cached; action events are not replay-cached.
- Ban, connection throttle and packet-rate checks remain server-side.

## Publish

Linux self-contained:

```bash
dotnet publish CommonwealthOnline.Server.csproj -c Release -r linux-x64 --self-contained true -p:PublishSingleFile=true -o publish/linux-x64
```

Windows self-contained:

```bat
dotnet publish CommonwealthOnline.Server.csproj -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true -o publish\win-x64
```

`commonwealth-online.service.example` is provided for Linux systemd deployment.