ReSkate/Server/README-linux.md

ReSkate dedicated server on Linux

Native x86_64 build. Same lobby protocol as ReSkateServer.exe; needs no game install. A release build updates itself, like the Windows server: see Updating.

Requirements

• 64-bit Linux (tested: CachyOS/Arch, Ubuntu 22.04+ should work).
• cmake >= 3.24, g++ >= 12 (C++20), libssl-dev (OpenSSL), libcurl headers optional (not needed for V1).
• curl on the machine that runs the server: it is how the server reads the ReSkate team's global ban list (api.reskate.dev) and how it downloads its own updates. Without it the server says so in its log, enforces only its own bans and stays on its version.
• tar (with gzip) on that machine too, to unpack an update.
• Steam shared libs beside the binary: libsteam_api.so + steamclient.so (Valve proprietary, not in git — but bundled in the CI/release assets, like the Windows zip bundles its DLLs; otherwise fetch them, see below).

Where the Steam .so files come from

Same split as Windows (steam_api64.dll + steamclient64.dll/tier0_s64.dll/vstdlib_s64.dll): the release ZIP is expected to ship them; this repo never vendors Valve binaries (see External/README.md, External/manifest.json).

• libsteam_api.so: from the Steamworks SDK redistributable_bin/linux64/ (official download via partner.steamgames.com; any recent 1.x works — the server tries SteamGameServerNetworkingSockets_SteamAPI_v013 then v012, and uses stable flat exports SteamGameServer015/SteamNetworkingUtils004). It is generic; the app is selected at runtime via SteamAppId=3354750.
• steamclient.so (+ tier0/vstdlib if present): not in the SDK. Get it from SteamCMD or a Steam client install, e.g.:

  steamcmd +@sSteamCmdForcePlatformType linux +login anonymous +app_update 1007 +quit
  # then copy steamapps/common/Steamworks\ SDK\ Redist/linux64/steamclient.so
  # next to ReSkateServer (same folder as libsteam_api.so)
  

  or copy/symlink an existing client copy (~/.steam/steam/linux64/steamclient.so, Valve also documents ~/.steam/sdk64/steamclient.so — the server looks there, so ln -s <folder>/steamclient.so ~/.steam/sdk64/steamclient.so works). The server dlopens libsteam_api.so, which in turn loads steamclient.so; either adjacent or LD_LIBRARY_PATH works.

Arch/CachyOS:

sudo pacman -S base-devel cmake openssl

Ubuntu/Debian:

sudo apt install build-essential cmake libssl-dev

Build

cmake --preset linux-x64
cmake --build --preset linux-release -j$(nproc)
./build/linux/ReSkateServer

Binary: build/linux/ReSkateServer (ELF, OUTPUT_NAME ReSkateServer).

Portable tests:

cmake --preset linux-x64 -DDINGOSDK_BUILD_MULTIPLAYER_TESTS=ON
cmake --build --preset linux-release -j$(nproc)
ctest --test-dir build/linux --output-on-failure

Expected: 9 passed (multiplayer_parties, server_activity, server_speed_check, server_config, server_global_bans, word_filter, multiplayer_bandwidth, multiplayer_lanes, multiplayer_prediction). Windows-only tests (voice, lobbies, UI) stay WIN32-gated.

Run

1. Put ReSkateServer in its own folder, then fetch the Steam libs (shipped as setup-linux-server-libs.sh beside the binary):

   ./setup-linux-server-libs.sh    # uses the folder it sits in; or --server-dir DIR
   

   Or do it by hand, see below.
2. First run writes ReSkateServer.json; edit name + admins, restart.
3. Optional: world-layers.json for time-of-day / world layers. Normal server runs only read this file (world_layer_scan::read, JSON only) and work on Linux — verified. Get it by either:
   • Windows export once: ReSkateServer.exe --export-world-layers "<Skate folder>" world-layers.json, then copy to the Linux folder; or
   • copy from a Windows player's cache %LOCALAPPDATA%\ReSkate\cache\<build>\world-layers.json (same game build; the server tells admins this path in layer-sync errors). Without it every player keeps their own layers; with it + world_layer_sync the server forces them.
4. No ports need opening (Steam relay). Optional UDP 27015-27016 (port, query_port) for browser ping + faster joins.

Without libsteam_api.so the server exits 1 with: Cannot load .../libsteam_api.so. Put libsteam_api.so (Steamworks SDK) next to the server.

Full command list: Server/README.txt (same on Linux; binary name differs).

systemd

See contrib/reskate-server.service. Install:

sudo cp contrib/reskate-server.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now reskate-server

The server writes its own ReSkateServer.log next to the binary; the console output goes to the journal (journalctl -u reskate-server -f).

Updating

A server from a release tarball updates itself the way the Windows one does: at startup and every half hour it asks GitHub for the latest release, and when that holds a newer Linux server it installs it once nobody is on, then carries on as the new version. update in the console does it straight away. "auto_update": false in ReSkateServer.json, or --no-update, turns it off. A server you built yourself never replaces itself.

• The release's launcher.json pins the tarball and the ReSkateServer inside it by SHA-256; nothing else is installed. The download is curl over HTTPS and the unpacking is tar, so both must be on the machine.
• Everything in the tarball is replaced in the server's folder (the server, the Steam libraries, the readmes, world-layers.json). Your own files are not in it and are kept: ReSkateServer.json, Mods, the logs.
• The user the server runs as must be able to write to the server's folder. With the systemd unit below that is reskate and /opt/reskate-server: sudo chown -R reskate: /opt/reskate-server.
• The updated server takes over the same process, so systemd (or your terminal) keeps the server it started; nothing restarts the service.
• A release made before this (1.1.3 and older) has no Linux entry in launcher.json: the server logs that the latest release has no Linux server and stays as it is. To get onto a self-updating version from one of those, replace the files once by hand.

Notes / limits (V1)

• --export-world-layers on Linux: the reader works, the scanner needs the Windows game (Data/layout.toc + CAS) and oo2core_9_win64.dll (Oodle). Oodle blocks throw Oodle CAS data is only supported on Windows (caught, exit 1, no crash). Export on Windows, copy the JSON over — no game needed on the server itself.
• content_cache dir: %LOCALAPPDATA% on Windows, $XDG_CACHE_HOME/~/.cache on Linux.
• Crypto interop verified: OpenSSL PKCS5_PBKDF2_HMAC(SHA256, 100k) + HMAC-SHA256 matches Windows BCrypt (checked against Python hashlib).