open-zone

An open ZoneMatch server for Dungeon Siege 1.

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Overview

This repo hosts:

• a native DirectPlay8 server shim (dp8shim/), and
• a single Go runtime (cmd/open-zone/) that implements the app-layer protocol above DP8 and serves a minimal News endpoint.

If you are trying to understand the protocol, start with:

• docs/design.md (architecture)
• docs/dp8-messages.md (DP8 app-protocol schemas + flows)

What Works

• DP8 transport works via Windows dpnet.dll.
• The game advances past "Connecting to ZoneMatch Server..." using app-protocol replies:
  • ConnectRes, ConInfoRes, ConnectEv
• Games list refresh works (headers + page results can render rows), and host-published HostData state is ingested.

Working Flows

See docs/dp8-messages.md for message shapes and sequencing.

• Connect (Internet entry): Connect -> ConnectRes + ConInfoRes + ConnectEv
• Games list (browse): HdrRow -> HdrRowRes, then Page -> PageRes (rows under <PageRes> as <Row .../>)
• Game details (staging/details refresh): RowPg -> RowPgRes
• Hosting updates: SetLoc -> SetLocRes, HostData -> HostDataRes (server stores host state and uses it for browse rows)
• News: HTTP on :2301 (GET / serves news.txt)
• AutoUpdate: optional "fail fast" TCP sink on :80 (accept+close, not a real AutoUpdate implementation)

Not Working Flows

• AutoUpdate: nothing will auto-update (no HTTP handler / update protocol support). The optional port 80 sink only exists to fail fast and avoid UI timeouts.
• Chat: no chat room / lobby chat support.
• Accounts: no sign-in / create-account support.

Notes:

• Join requires IpAddr to be populated in the browse row; the client can connect directly to the host.

Requirements

Runtime:

• Windows (DirectPlay8 runtime is dpnet.dll)
• Go 1.26 (see go.mod)

Build-time (for the shim):

• Visual Studio 2022 Build Tools (or VS) with Desktop development with C++
• DirectX headers are vendored into dp8shim/include/

Ports

This project runs three local listeners by default:

• DP8 + app-protocol: 2300 (transport handled by DirectPlay)
• News (HTTP): 2301 (GET / serves news.txt)
• AutoUpdate sink (TCP): 80 (accept+close to fail fast; no update support)

Quickstart

Option A: mise (recommended)

If you use mise, it can install tool versions and provide common commands via mise run ....

1. Install tools:

mise install

2. Build the shim (Windows):

mise run build-shim

3. Run:

mise run run

4. Optional: hot reload:

mise run setup-tools
mise run dev

Option B: manual

1. Build the shim (outputs bin/dp8shim.dll):

cd dp8shim
.\build.ps1

2. Run the server:

go run ./cmd/open-zone

3. Point the game at your machine (edit the multiplayer settings) to use the local servers:

[multiplayer]
gun_server = 127.0.0.1
gun_server_port = 2300
news_server = 127.0.0.1
news_server_port = 2301
news_server_file = /
autoupdate_server = 127.0.0.1
autoupdate_proxy = 127.0.0.1

Notes:

• The autoupdate_* values are only to point the client at the optional port 80 fail-fast sink (to avoid UI timeouts). This project does not implement AutoUpdate.

4. Optional: hot reload (requires air):

go install github.com/air-verse/air@latest
air

Configuration

Config file (optional):

• config/config.yaml

Env overrides:

• prefix OZ_
• . becomes _ (example: dp8.port -> OZ_DP8_PORT)

Useful knobs:

• dp8.port (default 2300)
• news.port (default 2301)
• autoupdate.port (default 80, set to 0 to disable)
• shim.path (default bin\\dp8shim.dll)
• telemetry.dp8_ndjson_path (empty disables NDJSON file logging)

Remote hosting: Set dp8.advertise_ip and dp8.advertise_port to the public hostname/IP and port clients should use to reach this server (e.g. your VM’s public IP and 2300). Leave empty/0 for local-only (defaults to 127.0.0.1:<dp8.port>). This affects the ConInfoRes reply sent to connecting clients.

Logs

• Console logging: always on
• App-protocol telemetry (NDJSON): logs/dp8.ndjson (only when enabled)

Repo Layout

• cmd/open-zone/: main entrypoint
• internal/
  • internal/config/: config loading + defaults
  • internal/dp8/: DP8 event loop + send queue
  • internal/dp8shim/: Go loader for bin/dp8shim.dll
  • internal/proto/: XML-ish message parsing + protocol handlers + host state
  • internal/news/: minimal News HTTP server
  • internal/autoupdate/: best-effort AutoUpdate “fail fast” sink (no update support)
  • internal/packetlog/: NDJSON logger
• dp8shim/: native shim source + build scripts
• bin/: runtime binaries (see bin/README.md)
• docs/: protocol/design docs

Building a deploy bundle

mise run deploy-build produces a portable Windows x64 bundle under ./deploy/ that you can copy to another machine.

What it does:

1. Fresh output directory
   Removes any existing deploy/ and recreates deploy/, deploy/bin, and deploy/config.

2. Shim
   Runs the same shim build as mise run build-shim. If dp8shim.dll is in use (e.g. server running), the build is skipped and the existing DLL is used for staging.

3. Server binary
   Builds the Go server for Windows x64:

   • GOOS=windows, GOARCH=amd64, CGO_ENABLED=0
   • go build -trimpath -ldflags "-s -w" → deploy/open-zone.exe

4. Staged artifacts
   Copies into deploy/:

   • bin/dp8shim.dll (and bin/dp8shim.pdb if present) → deploy/bin/
   • config/config.yaml → deploy/config/
   • README.md, run-server.bat, and docs/ → deploy/

Usage:

mise run deploy-build

The resulting deploy/ folder can be run on any Windows x64 machine; run open-zone.exe from the deploy directory (it expects bin/dp8shim.dll and config/config.yaml relative to the current directory).

Dev (Format/Lint)

With mise:

mise run fmt
mise run lint
mise run test

Without mise:

gofmt -w .
go test ./...
go run github.com/golangci/golangci-lint/cmd/golangci-lint@v1.63.4 run ./...

Troubleshooting

• DP8_StartServer failed hr=0x80070005 (E_ACCESS_DENIED) when running remotely (e.g. on a VM)
  The DirectPlay8 stack is being blocked from binding to the DP8 port (default 2300). Fix both:

  1. VM / cloud firewall – In the cloud console (AWS security group, Azure NSG, GCP firewall, etc.), allow inbound TCP 80, UDP 2300, and TCP 2301 (HTTP News) to the VM.
  2. Windows Firewall on the VM – Add inbound rules. In PowerShell (run as Administrator):
     New-NetFirewallRule -DisplayName "open-zone DP8" -Direction Inbound -Protocol UDP -LocalPort 2300 -Action Allow
New-NetFirewallRule -DisplayName "open-zone News" -Direction Inbound -Protocol TCP -LocalPort 2301 -Action Allow
New-NetFirewallRule -DisplayName "open-zone AutoUpdate" -Direction Inbound -Protocol TCP -LocalPort 80 -Action Allow
  • Ensure the process runs under an account that can open listening sockets (usually any normal user can).

• Running on remote servers (VM / Windows Server)
  DirectPlay is not enabled by default. On the server, run in an elevated command prompt, then reboot:

  dism /online /enable-feature /featurename:LegacyComponents /all /norestart
  dism /online /enable-feature /featurename:DirectPlay /all /norestart
  shutdown /r /t 0
  

• Join times out when a player hosts a game
  open-zone is the ZoneMatch lobby server; joining a game connects directly to the host’s machine via DirectPlay. If the host is behind NAT, the joiner cannot reach them unless the host’s router forwards the game session ports to the host:

  • 6073 UDP – primary (inbound for hosting, outbound for joining)
  • 2302–2400 UDP – secondary ZoneMatch (2300 UDP) is only for the lobby. Without port forwarding on the host’s NAT, join will time out even when the Games list shows the correct host IP.

• dp8shim fails to load

  • Ensure bin/dp8shim.dll exists (run dp8shim/build.ps1)
  • Ensure bitness matches (this Go app is windows/amd64; shim must be x64)

• No DP8/app-protocol logs when you click UI buttons

  • NDJSON logging is off by default: set telemetry.dp8_ndjson_path to enable.

• Rebuilding dp8shim.dll

  • Stop the Go process first (Windows locks loaded DLLs).