Initial Commit

.gitignore

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+npm-debug.log
+dist
+node_modules
+.DS_Store

.prettierignore

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+dist
+generated
+.vscode
+package-lock.json
+package.json

README.md

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+# AOL Instant Messenger Server
+
+This is a (very wip) server-side implementation of the [Oscar Protocol](https://en.wikipedia.org/wiki/OSCAR_protocol), used by [AOL Instant Messenger](<https://en.wikipedia.org/wiki/AIM_(software)>) and later versions of [ICQ](https://en.wikipedia.org/wiki/ICQ).
+
+## Working
+
+-   AIM Client can establish connection and server can send and receive the FLAP SIGNON frame
+-   Can receive initial auth flap from client
+
+## Oscar Protocol Resources
+
+-   http://web.archive.org/web/20080308233204/http://dev.aol.com/aim/oscar/ (AOL published Oscar protocol documentation in the mid 00s)
+-   http://iserverd.khstu.ru/oscar/ (Unofficial protocol docs, pretty thorough)
+-   https://wiki.nina.bz/wiki/Protocols/OSCAR (From the Nina group also working on an OSCAR server)
+-   https://github.com/bitm4ster/AOL-Instant-Messenger-Server/ (Oscar server written in VB6. and it actually compiles!)
+-   http://iserverd.khstu.ru/download/ (Oscar Server written in C++. Haven't attempted to compile yet, but a great reference)

package.json

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+{
+  "name": "aim-server",
+  "private": true,
+  "version": "0.0.1",
+  "description": "An AOL Instant Messenger Server. Implements a subset of the Oscar Protocol",
+  "main": "index.js",
+  "scripts": {
+    "build": "tsc",
+    "watch": "tsc --watch",
+    "format:check": "prettier --list-different '**/*.{js,ts,md,json}'",
+    "format": "prettier --write '**/*.{js,ts,md,json}'"
+  },
+  "author": "Andrew Levine",
+  "license": "MIT",
+  "devDependencies": {
+    "@types/node": "^14.14.11",
+    "prettier": "^2.2.1",
+    "typescript": "^4.1.2"
+  }
+}

prettier.config.js

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+module.exports = {
+    singleQuote: true,
+    tabWidth: 4,
+    trailingComma: 'all',
+};

src/index.ts

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+import net from 'net';
+import assert from 'assert';
+
+interface Flap {
+    channel: number;
+    sequence: number;
+    byteLength: number;
+    data: Buffer;
+}
+
+/**
+ * @see https://en.wikipedia.org/wiki/OSCAR_protocol#FLAP_header
+ */
+function parseFlap(msg: Buffer): Flap {
+    const id = msg.readUInt8(0);
+    assert(id === 0x2a, 'Unexpected Flap ID');
+
+    return {
+        channel: msg.readUInt8(1),
+        sequence: msg.readUInt16BE(2),
+        byteLength: msg.readUInt16BE(4),
+        data: Buffer.from(msg, 6),
+    };
+}
+
+/**
+ * @see http://web.archive.org/web/20080308233204/http://dev.aol.com/aim/oscar/#FLAP__SIGNON_FRAME
+ */
+function signonFlap() {
+    const buf = Buffer.alloc(7);
+    buf.writeUInt8(0x2a, 0); // start byte
+    buf.writeUInt8(0x1, 1); // flap channel
+    buf.writeUInt16BE(0x1, 2); // sequence number
+    buf.writeUInt16BE(0x1, 4); // data size (flap version)
+    buf.writeUInt8(0x1, 6); // flap version
+
+    return buf;
+}
+
+const server = net.createServer((c) => {
+    console.log('New socket opened');
+
+    c.on('end', () => {
+        console.log('client disconnected');
+    });
+
+    c.on('connect', () => console.log('Socket connected'));
+    c.on('error', (e) => console.log('Socket error', e));
+    c.on('close', () => {
+        console.log('socket closed');
+    });
+
+    function onChannel2Message(flap: Flap) {
+        console.log('Channel 2 Flap: ', flap);
+    }
+
+    c.on('data', (buf) => {
+        const flap = parseFlap(buf);
+        // http://web.archive.org/web/20080308233204/http://dev.aol.com/aim/oscar/#FLAP__FRAME_TYPE
+        switch (flap.channel) {
+            case 1:
+                // SIGNON frame response
+                // TODO: assert flap version is always 1
+                break;
+            case 2:
+                onChannel2Message(flap);
+                break;
+            case 3:
+                // FLAP-level error
+                // TODO: Error logging
+                break;
+            case 4:
+                // Signoff negotiation
+                // TODO: Implement when sessions are implemented
+                break;
+            case 5:
+                // Keep-alive heartbeat
+                // TODO: Implement when sessions are implemented
+                break;
+            default:
+                throw new Error(`Unrecognized FLAP channel "${flap.channel}"`);
+        }
+    });
+
+    // Send OSCAR connection handshake
+    c.write(signonFlap());
+});
+
+server.on('error', (err) => {
+    console.error('Server crashed. Welp');
+    console.error(err);
+    process.exit(1);
+});
+
+server.listen(5190, () => {
+    console.log('Oscar Auth Server listening on 5190');
+});

tsconfig.json

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+{
+    "compilerOptions": {
+        "inlineSourceMap": true,
+        "inlineSources": true,
+        "strict": true,
+        "target": "ES2020",
+        "module": "commonjs",
+        "moduleResolution": "node",
+        "esModuleInterop": true,
+        "outDir": "dist",
+        "noImplicitAny": true,
+        "noEmitOnError": false,
+        "resolveJsonModule": true
+    },
+    "include": ["src/**/*"],
+    "exclude": ["node_modules", "**/__tests__/**"]
+}