From 829e10437eae82c87d07d9f26ed7deea1eda02fc Mon Sep 17 00:00:00 2001
From: Thayol <thayol@zovguran.net>
Date: Wed, 8 Jul 2026 21:44:11 +0200
Subject: [PATCH] Initial commit

---
 .gitignore         |   2 +
 README.md          |  13 +++++
 config.php.example |   7 +++
 enet_probe.php     |  57 ++++++++++++++++++
 index.php          | 141 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 220 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100644 config.php.example
 create mode 100644 enet_probe.php
 create mode 100644 index.php

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3615400
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+state.json
+config.php
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8e4979d
--- /dev/null
+++ b/README.md
@@ -0,0 +1,13 @@
+# Supercardinality Online Services
+
+The reference implementation for online services for Supercardinality.
+
+## Setup
+
+Create the `config.php` file based on `config.php.example`.
+
+Host the repo root using a PHP capable web server.
+
+It's a good idea to block access to your state file.
+A common way to protect it from being publicly readable is to configure it to be outside of the web server.
+If you store it in the default location you may want to block access to it using URL rewrite rules.
diff --git a/config.php.example b/config.php.example
new file mode 100644
index 0000000..8c18ccd
--- /dev/null
+++ b/config.php.example
@@ -0,0 +1,7 @@
+<?php
+
+$state_file = "state.json"; // The location for the state file. If it does not exist, it will be created.
+
+$error_reporting = false; // Whether PHP errors should be shown. Not recommended for production.
+
+$lobby_timeout_seconds = 30; // How long it should take for unresponsive lobbies to get auto-delisted.
diff --git a/enet_probe.php b/enet_probe.php
new file mode 100644
index 0000000..5336863
--- /dev/null
+++ b/enet_probe.php
@@ -0,0 +1,57 @@
+<?php
+
+function enet_probe(string $host, int $port, float $timeout = 2.0): bool
+{
+    $host = trim($host);
+    $addr = filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)
+        ? "[{$host}]"
+        : $host;
+
+    $sock = @stream_socket_client(
+        "udp://{$addr}:{$port}",
+        $errno, $errstr, $timeout, STREAM_CLIENT_CONNECT
+    );
+    if ($sock === false) return false;
+
+    stream_set_timeout($sock,
+        (int) floor($timeout),
+        (int) (fmod($timeout, 1.0) * 1_000_000)
+    );
+
+    $connectID = mt_rand(1, 0x7FFFFFFF);
+
+    // --- Protocol header (4 bytes, NO CRC32) ---
+    // 0x8FFF = SENT_TIME flag (0x8000) | peer 0xFFF (max/unassigned)
+    $header = pack('nn', 0x8FFF, 0);
+
+    // --- Command header (4 bytes) ---
+    $cmdHeader = pack('CCn', 0x82, 0xFF, 1);
+
+    // --- Connect body (44 bytes) ---
+    $cmdBody  = pack('n', 0);             // outgoingPeerID
+    $cmdBody .= pack('CC', 0xFF, 0xFF);   // incomingSessionID, outgoingSessionID
+    $cmdBody .= pack('N', 1400);          // mtu
+    $cmdBody .= pack('N', 65536);         // windowSize
+    $cmdBody .= pack('N', 2);             // channelCount
+    $cmdBody .= pack('N', 0);             // incomingBandwidth
+    $cmdBody .= pack('N', 0);             // outgoingBandwidth
+    $cmdBody .= pack('N', 5000);          // packetThrottleInterval
+    $cmdBody .= pack('N', 2);             // packetThrottleAcceleration
+    $cmdBody .= pack('N', 2);             // packetThrottleDeceleration
+    $cmdBody .= pack('N', $connectID);    // connectID
+    $cmdBody .= pack('N', 0);             // data
+
+    $packet = $header . $cmdHeader . $cmdBody;
+
+    $written = @fwrite($sock, $packet);
+    if ($written !== strlen($packet)) {
+        fclose($sock);
+        return false;
+    }
+
+    $response = @fread($sock, 512);
+    $meta = stream_get_meta_data($sock);
+    fclose($sock);
+
+    return !$meta['timed_out'] && $response !== '' && $response !== false;
+}
diff --git a/index.php b/index.php
new file mode 100644
index 0000000..dba1537
--- /dev/null
+++ b/index.php
@@ -0,0 +1,141 @@
+<?php
+
+function generate_uuid_v4(): string {
+  $bytes = openssl_random_pseudo_bytes(16);
+  $bytes[6] = chr(ord($bytes[6]) & 0x0f | 0x40); // set version to 0100
+  $bytes[8] = chr(ord($bytes[8]) & 0x3f | 0x80); // set bits 6-7 to 10
+  return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($bytes), 4));
+}
+
+if (file_exists("config.php")) {
+  include "config.php";
+}
+
+if (empty($state_file)) {
+  $state_file = "state.json";
+}
+
+if (empty($error_reporting)) {
+  $error_reporting = false;
+}
+
+if (empty($lobby_timeout_seconds)) {
+  $lobby_timeout_seconds = 30;
+}
+
+if ($error_reporting) {
+  error_reporting(E_ALL);
+  ini_set('display_errors', 1);
+}
+
+if (!file_exists($state_file)) {
+  mkdir($state_file, 0777, true);
+  file_put_contents($state_file, json_encode([ "lobbies" => []]));
+}
+
+$state = json_decode(file_get_contents($state_file), true);
+
+$cutoff_timestamp = time() - $lobby_timeout_seconds;
+foreach (array_keys($state["lobbies"]) as $id) {
+  if ($state["lobbies"][$id]["updated_at"] < $cutoff_timestamp) {
+    unset($state["lobbies"][$id]);
+  }
+}
+
+if (isset($_GET["list"])) {
+  $list = [];
+  foreach ($state["lobbies"] as $id => $lobby) {
+    $list[$id] = [
+      "id" => $lobby["id"],
+      "host" => $lobby["host"],
+      "name" => $lobby["name"],
+      "creator" => $lobby["creator"],
+      "version" => $lobby["version"],
+      "created_at" => $lobby["created_at"],
+    ];
+  }
+  header("Content-Type: application/json");
+  echo json_encode(["lobbies" => $list]);
+}
+elseif (isset($_GET["new"])) {
+  require "enet_probe.php";
+  $host = $_SERVER['REMOTE_ADDR'];
+  if (!empty($_GET["host"])) {
+    $host = $_GET["host"];
+  }
+  $reachable = enet_probe($host, 50403);
+  header("Content-Type: application/json");
+  if ($reachable) {
+    $id = generate_uuid_v4();
+    $secret = generate_uuid_v4();
+    $version = $_GET["version"] ?? "";
+    $creator = $_GET["creator"] ?? "";
+    $name = "{$creator}'s lobby";
+    if (!empty($_GET["name"])) {
+      $name = $_GET["name"];
+    }
+    $lobby = [
+      "id" => $id,
+      "secret" => $secret,
+      "host" => $host,
+      "name" => $name,
+      "version" => $version,
+      "creator" => $creator,
+      "updated_at" => time(),
+      "created_at" => time(),
+    ];
+    $state["lobbies"][$id] = $lobby;
+    echo json_encode($lobby);
+  }
+  else {
+    http_response_code(424);
+    echo json_encode(["error" => "NOT_REACHABLE", "host" => $host]);
+  }
+}
+elseif (isset($_GET["update"])) {
+  $id = $_GET["id"];
+  $secret = $_GET["secret"];
+  $lobby = $state["lobbies"][$id];
+  header("Content-Type: application/json");
+  if (!in_array($id, array_keys($state["lobbies"])) || empty($lobby)) {
+    http_response_code(404);
+    echo json_encode(["error" => "NOT_FOUND", "id" => $id]);
+  }
+  elseif ($lobby["secret"] != $secret) {
+    http_response_code(403);
+    echo json_encode(["error" => "NOT_AUTHORIZED", "id" => $id]);
+  }
+  else {
+    $name = $_GET["name"] ?? "";
+    if (!empty($name)) {
+      $lobby["name"] = $name;
+    }
+    $lobby["updated_at"] = time();
+    $state["lobbies"][$id] = $lobby;
+    echo json_encode(["result" => "updated"]);
+  }
+}
+elseif (isset($_GET["close"])) {
+  $id = $_GET["id"];
+  $secret = $_GET["secret"];
+  $lobby = $state["lobbies"][$id];
+  header("Content-Type: application/json");
+  if (!in_array($id, array_keys($state["lobbies"])) || empty($lobby)) {
+    http_response_code(404);
+    echo json_encode(["error" => "NOT_FOUND", "id" => $id]);
+  }
+  elseif ($lobby["secret"] != $secret) {
+    http_response_code(403);
+    echo json_encode(["error" => "NOT_AUTHORIZED", "id" => $id]);
+  }
+  else {
+    unset($state["lobbies"][$id]);
+    echo json_encode(["result" => "closed"]);
+  }
+}
+else {
+  header("Content-Type: application/json");
+  echo json_encode(["status" => "OK"]);
+}
+
+file_put_contents($state_file, json_encode($state, JSON_PRETTY_PRINT));