d2-clientless

# clientless A clientless Diablo II **1.14d** Battle.net client, written in Zig. It speaks the wire protocols directly — **BNCS** (login), **MCP** (realm/characters), **BNFTP** (file transfer), and the **D2GS** game protocol — with **no game binary, no wine, and no graphics**. One small static binary connects, authenticates, picks a realm, creates/selects a character, joins a game, and receives the live in-game packet stream. ## Why this exists This is the **test client for [jaenster/d2-dedicated-server](https://github.com/jaenster/d2-dedicated-server)** — a clean-room Zig reimplementation of the Diablo II closed-realm servers (the `realmd` triplet: bnetd + d2cs + d2dbs, plus a headless game server). To know that server actually works, you need something that talks the *client* side of the protocol. The real game client is a closed-source Windows binary that needs graphics, wine, and the proprietary data files — useless for automated testing. `clientless` is the answer: it drives the **entire** client→server handshake from a script, so the server's auth, realm, character, and game-join paths can be exercised **in CI and by hand**, on every commit, with no game install. It's also a faithful, readable reference for how the 1.14d closed-Battle.net protocol works, and it runs against real Battle.net too (it was validated end-to-end against a live gateway). ## What it can do - **Version check** — computes the modern base64 CheckRevision response (`checkrev_core`, the 1.14d `CheckRevision.mpq` algorithm) and the CD-key auth blocks for `SID_AUTH_CHECK`. - **Accounts** — log in to, or create, an account over OLS (Blizzard's broken-SHA-1 password hash). - **Realm** — list realms and log on to one, then over **MCP**: list/create/select characters, read the ladder. - **Chat** — enter chat, join a channel, send messages, `/kick`, and listen for events. - **Game** — create or join a game and **enter it on the game server**: `GAMELOGON (0x68)` → wait for the GS `0x02` LoadSuccess → `JOINGAME (0x6b)`, then read the S→C game stream (opcode-framed; `0xAE` huffman blobs are decompressed) — character assignment, act load, unit spawns, stat updates, quests. - **BNFTP** — discover and download server files (the `bnftp` subcommand). - Works against **your own realm** (realmd/pvpgn) *and* **real Battle.net**; handles both the modern base64 challenge and the legacy `A=1 B=1 …` formula; runs **keyless** on a permissive realm. ## What it can't (and won't) do - **It is not a bot.** It performs the join handshake, parses the incoming packet stream, and prints what it sees — but it does **not** model game state (no player/unit/position tracking) and does **not** act in the world (no movement, no skills, no item pickup). It's a protocol harness, not an automation framework. - **It doesn't stay in-game.** After joining it reads the stream for a short window and exits; there's no long-lived session / keep-alive loop. - **No native Windows binary.** The socket layer is POSIX; on Windows run it via the container (Docker Desktop / WSL2). A Winsock port is possible but not done. - **Classic challenge is a placeholder.** Against the legacy `A=1 B=1 …` formula it sends a placeholder hash, which only a permissive realm accepts — it does not compute a real classic CheckRevision (that needs the game files). - **No anti-cheat work.** It does not run, forge, or bypass the lockdown / extra-work (Warden-style) modules. Game entry doesn't require them, so it simply doesn't engage them; it won't be extended to defeat them on a live service. - **One session per run, single-threaded.** No connection pooling, no concurrency. ## Install One line (Linux / macOS / FreeBSD) — detects your OS/arch, grabs the latest release binary: curl -fsSL https://raw.githubusercontent.com/jaenster/d2-clientless/main/install.sh | sh Or grab a tarball yourself from the [Releases](https://github.com/jaenster/d2-clientless/releases) page — **Linux** (x86_64, aarch64, armv7, riscv64, static musl), **macOS** (x86_64, aarch64), and **FreeBSD** (x86_64, aarch64). Or run the [container](#container). ## Build Requires **Zig 0.16**. Produces a single binary: zig build # -> zig-out/bin/clientless zig build test # crypto unit tests (CheckRevision / CD-key / xSHA-1) ## Usage clientless <host> [product] [version] [options] # BNCS / MCP / chat / game clientless bnftp [options] <host> [product] [file] # BNFTP file client Run `clientless` with no arguments for the full, sectioned help. Common flags: | flag | meaning | |-|-| | `--keys K1[,K2]` | 26-char CD-key(s); omit on a permissive realm | | `--login acct:pass` / `--create acct:pass` | log in / register then log in | | `--game <name>` (`--gs-port <n>`) | create + join a game and enter it on the GS | | `--channel/--say/--kick/--listen <sec>` | chat | | `--verbyte <n>` | GAMELOGON version byte (default 14 = 1.14d) | | `--force-checkrev` | answer even if the version-check MPQ isn't `CheckRevision.mpq` | | `--sig0` / `--delay <ms>` / `--verbose` | sigOk=0 / pace each step / hexdump all traffic | ### Examples # version check only — no keys, no account clientless useast.battle.net # full session on your own realm: create a char, chat, read the ladder clientless realm.example.com D2XP 1.14.3.71 --login me:pw --listen 20 # create the account, then create + enter a game clientless realm.example.com D2XP 1.14.3.71 --create me:pw --game MyGame # two clients chatting; the operator kicks the other clientless realm.example.com --login op:pw --channel ops --kick rude # live Battle.net with real CD-keys (your account, your responsibility) clientless useast.battle.net D2XP 1.14.3.71 --keys K1,K2 --login acct:pw --game MyGame # BNFTP: a file's size, then download it clientless bnftp --head useast.battle.net D2XP CheckRevision.mpq clientless bnftp --out-dir . useast.battle.net D2XP CheckRevision.mpq ## How the game join works `GAMELOGON (0x68)` carries the JOINGAME token + game hash + character name (the exact `D2GSPacketClt0x68` field layout). The client first **waits for the GS's `0xAF`** connection packet (like the real client's connecting loop), then sends `0x68`, reads the S→C stream **framed by opcode + the engine's size table** (not length-prefixed), and sends `JOINGAME (0x6b)` only in response to the server's `0x02` LoadSuccess. Compressed `0xAE` blobs are huffman-decompressed (`src/huffman.zig`) and their inner packets parsed. ## The three hashes Easy to conflate; they are distinct: 1. **CheckRevision** — standard SHA-1. `checkrev_core` implements the 1.14d `CheckRevision.mpq` algorithm specifically; against any other version-check MPQ it refuses to answer (so it never sends a wrong response) unless `--force-checkrev`. 2. **CD-key block** — standard SHA-1 over `clientToken ++ serverToken ++ product ++ public ++ value`. 3. **Account password** — Blizzard's *broken* SHA-1 (`src/xsha1.zig`): single-bit-rotate message schedule, little-endian I/O, zero padding. ## Container docker run --rm ghcr.io/jaenster/d2-clientless <host> D2XP 1.14.3.71 --login acct:pass docker run --rm ghcr.io/jaenster/d2-clientless bnftp --head <host> D2XP CheckRevision.mpq Multi-arch (linux/amd64 + arm64), static musl on `scratch`. This is also how to run it on Windows or macOS (Docker Desktop / WSL2), since there's no native binary for those yet. ## CI `zig build` + `zig build test` run on every push. The `e2e` job checks out [d2-dedicated-server](https://github.com/jaenster/d2-dedicated-server), builds `realmd`, and drives a full session against it (auth → create → login → MCP → char → ladder → chat) — see `ci/e2e.sh`. Game entry needs a real game server (the proprietary `Game.exe` under wine), so `ci/e2e-game.sh` runs only on a self-hosted runner with the D2 files. ## Notes & credits - Talking to live Battle.net sends your CD-keys and credentials — rate limits and ToS are your responsibility. Against your own realm it's just a test client. - No keys or credentials are committed; they are arguments. Unit tests use synthetic vectors. - The D2GS huffman tables in `src/huffman.zig` are ported from [jaenster/D2PacketBased](https://github.com/jaenster/D2PacketBased). - Sockets go through libc (`std.net` was dropped in Zig 0.16); native host target.