feat: introduce 3-tier architecture with relay and exit nodes
This commit is contained in:
451
proxy-server.js
451
proxy-server.js
@@ -1,42 +1,24 @@
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#!/usr/bin/env node
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/**
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* PSK Proxy Out-Node (Server)
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* PSK Proxy Relay-Node (Server)
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*
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* Listens for a TLS-PSK tunnel connection from the proxy client.
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* Receives OPEN(host,port) to create outbound TCP connections to remote servers,
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* then forwards DATA/CLOSE frames bidirectionally.
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*
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* Also supports UDP relaying for SOCKS5 UDP ASSOCIATE via new UDP_* frames.
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*
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* Protocol (over a single TLS socket):
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* Header: [1 byte type][4 bytes connection id][4 bytes data length][data...]
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*
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* Message Types:
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* DATA (2): Carry TCP stream data
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* CLOSE (3): Close a TCP stream
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* OPEN (4): Open TCP stream to host:port, payload = [2B hostLen][host][2B port]
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* OPEN_RESULT (5): Result for OPEN, payload = [1B status] (1 = success, 0 = failure)
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*
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* UDP_OPEN (6): Create a UDP association (bidirectional relay); payload = empty
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* UDP_OPEN_RESULT (7): Result for UDP_OPEN, payload = [1B status] (1 = success, 0 = failure)
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* UDP_SEND (8): Send one UDP datagram to host:port
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* payload = [2B hostLen][host][2B port][2B dataLen][data...]
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* UDP_RECV (9): UDP datagram received from remote; same payload format as UDP_SEND
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* UDP_CLOSE (10): Close UDP association; payload = empty
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* Establishes a single TLS-PSK tunnel connection to an exit node.
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* Relays frames between the client and the exit node.
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*/
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const net = require('net');
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const tls = require('tls');
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const fs = require('fs');
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const dgram = require('dgram');
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const { program } = require('commander');
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program
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.requiredOption('-P, --tunnel-port <port>', 'Port for proxy client TLS-PSK tunnel connections')
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.requiredOption('-H, --host <host>', 'Host to bind to (e.g., 0.0.0.0)')
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.requiredOption('--psk-file <path>', 'Path to PSK key file')
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.option('--connect-timeout <ms>', 'Timeout for outbound TCP connect (ms)', '10000')
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.requiredOption('--psk-file <path>', 'Path to PSK key file for client and exit connections')
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.requiredOption('--exit-host <host>', 'Exit node host')
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.requiredOption('--exit-port <port>', 'Exit node port')
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.requiredOption('--exit-identity <identity>', 'PSK identity for the exit node')
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.parse();
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const options = program.opts();
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@@ -49,41 +31,20 @@ try {
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process.exit(1);
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}
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const OUT_CONNECT_TIMEOUT = parseInt(options.connectTimeout, 10) || 10000;
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// Global state
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let clientSocket = null;
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let exitSocket = null;
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let clientReader = null;
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let exitReader = null;
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// Message Types
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const MSG_TYPES = {
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DATA: 2,
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CLOSE: 3,
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OPEN: 4,
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OPEN_RESULT: 5,
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UDP_OPEN: 6,
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UDP_OPEN_RESULT: 7,
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UDP_SEND: 8,
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UDP_RECV: 9,
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UDP_CLOSE: 10,
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};
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function writeMessage(socket, type, connectionId, data = Buffer.alloc(0)) {
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if (!socket || socket.destroyed) return true;
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const buf = Buffer.allocUnsafe(9 + data.length);
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buf.writeUInt8(type, 0);
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buf.writeUInt32BE(connectionId >>> 0, 1);
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buf.writeUInt32BE(data.length >>> 0, 5);
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if (data.length > 0) data.copy(buf, 9);
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return socket.write(buf);
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}
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function createMessageReader() {
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function createMessageReader(onMessage) {
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let buffer = Buffer.alloc(0);
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let expectedLength = 9;
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let currentMessage = null;
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return function onData(data, callback) {
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return function onData(data) {
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buffer = Buffer.concat([buffer, data]);
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// Parse as many complete frames as possible
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while (buffer.length >= expectedLength) {
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if (!currentMessage) {
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const type = buffer.readUInt8(0);
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@@ -93,14 +54,14 @@ function createMessageReader() {
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expectedLength = 9 + dataLength;
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if (dataLength === 0) {
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callback(currentMessage.type, currentMessage.connectionId, Buffer.alloc(0));
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onMessage(currentMessage.type, currentMessage.connectionId, Buffer.alloc(0));
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buffer = buffer.subarray(9);
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currentMessage = null;
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expectedLength = 9;
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}
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} else {
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const messageData = buffer.subarray(9, expectedLength);
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callback(currentMessage.type, currentMessage.connectionId, messageData);
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onMessage(currentMessage.type, currentMessage.connectionId, messageData);
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buffer = buffer.subarray(expectedLength);
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currentMessage = null;
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expectedLength = 9;
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@@ -109,324 +70,120 @@ function createMessageReader() {
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};
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}
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function parseOpenPayload(buf) {
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if (buf.length < 4) return null;
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let offset = 0;
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const hostLen = buf.readUInt16BE(offset); offset += 2;
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if (buf.length < 2 + hostLen + 2) return null;
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const host = buf.subarray(offset, offset + hostLen).toString('utf8'); offset += hostLen;
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const port = buf.readUInt16BE(offset); offset += 2;
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return { host, port };
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function writeMessage(socket, type, connectionId, data = Buffer.alloc(0)) {
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if (!socket || socket.destroyed) return;
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const buf = Buffer.allocUnsafe(9 + data.length);
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buf.writeUInt8(type, 0);
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buf.writeUInt32BE(connectionId >>> 0, 1);
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buf.writeUInt32BE(data.length >>> 0, 5);
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if (data.length > 0) data.copy(buf, 9);
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socket.write(buf);
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}
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function buildOpenResultPayload(success) {
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const b = Buffer.allocUnsafe(1);
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b.writeUInt8(success ? 1 : 0, 0);
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return b;
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function connectToExitNode() {
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console.log(`Connecting to exit node ${options.exitHost}:${options.exitPort}...`);
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const pskCb = () => ({
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identity: options.exitIdentity,
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psk: Buffer.from(pskKey, 'hex'),
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});
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const sock = tls.connect(
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{
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host: options.exitHost,
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port: parseInt(options.exitPort, 10),
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pskCallback: pskCb,
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ciphers: 'PSK-AES256-GCM-SHA384:PSK-AES128-GCM-SHA256',
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checkServerIdentity: () => undefined,
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},
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() => {
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console.log('Connected to exit node');
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}
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);
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sock.setNoDelay(true);
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sock.setKeepAlive(true, 30000);
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exitSocket = sock;
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exitReader = createMessageReader((type, connId, data) => {
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// Forward messages from exit to client
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if (clientSocket && !clientSocket.destroyed) {
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writeMessage(clientSocket, type, connId, data);
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}
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});
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sock.on('data', (data) => exitReader(data));
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sock.on('close', () => {
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console.log('Disconnected from exit node. Retrying in 2s...');
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exitSocket = null;
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// If client is still here, it will be disconnected by the client server logic
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if (clientSocket) {
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try { clientSocket.destroy(); } catch (_) {}
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}
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setTimeout(connectToExitNode, 2000);
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});
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sock.on('error', (err) => {
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console.error('Exit node connection error:', err.message);
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});
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}
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function parseUdpPayload(buf) {
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// [2B hostLen][host][2B port][2B dataLen][data...]
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if (buf.length < 2) return null;
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let off = 0;
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const hostLen = buf.readUInt16BE(off); off += 2;
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if (buf.length < 2 + hostLen + 2 + 2) return null;
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const host = buf.subarray(off, off + hostLen).toString('utf8'); off += hostLen;
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const port = buf.readUInt16BE(off); off += 2;
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const dataLen = buf.readUInt16BE(off); off += 2;
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if (buf.length < 2 + hostLen + 2 + 2 + dataLen) return null;
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const data = buf.subarray(off, off + dataLen);
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return { host, port, data };
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}
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function buildUdpPayload(host, port, data) {
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const hostBuf = Buffer.from(host, 'utf8');
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const buf = Buffer.allocUnsafe(2 + hostBuf.length + 2 + 2 + data.length);
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let off = 0;
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buf.writeUInt16BE(hostBuf.length, off); off += 2;
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hostBuf.copy(buf, off); off += hostBuf.length;
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buf.writeUInt16BE(port, off); off += 2;
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buf.writeUInt16BE(data.length, off); off += 2;
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data.copy(buf, off);
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return buf;
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}
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function pskCallback(socket, identity) {
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console.log(`Tunnel client identity: ${identity}`);
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const clientPskCallback = (socket, identity) => {
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console.log(`Client identity: ${identity}`);
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return Buffer.from(pskKey, 'hex');
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}
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};
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let tunnelSocket = null;
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const upstreamConns = new Map(); // connectionId -> net.Socket
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// UDP association mapping: connectionId -> { udp4?: dgram.Socket, udp6?: dgram.Socket }
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const udpAssoc = new Map();
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// Framing and fairness controls
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const FRAME_MAX = 16 * 1024; // 16KiB frames to improve interleaving
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const BYTES_PER_TICK = 64 * 1024; // Limit per processing burst to yield event loop
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// Per-connection TX queues for upstream->tunnel direction
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const txQueues = new Map(); // connectionId -> { queue: Buffer[], sending: boolean }
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function processTxQueue(connectionId, state) {
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if (!tunnelSocket || tunnelSocket.destroyed) {
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// Drop queued data if tunnel is gone
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state.queue = [];
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state.sending = false;
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return;
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}
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if (state.sending) return;
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state.sending = true;
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let bytesThisTick = 0;
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const run = () => {
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if (!tunnelSocket || tunnelSocket.destroyed) {
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state.queue = [];
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state.sending = false;
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return;
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}
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while (state.queue.length) {
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const buf = state.queue[0];
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let offset = buf._offset || 0;
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while (offset < buf.length) {
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const end = Math.min(offset + FRAME_MAX, buf.length);
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const slice = buf.subarray(offset, end);
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const ok = writeMessage(tunnelSocket, MSG_TYPES.DATA, connectionId, slice);
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if (!ok) {
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// Backpressure: remember progress and resume on drain
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buf._offset = end;
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tunnelSocket.once('drain', () => {
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// Reset flag to allow re-entry
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state.sending = false;
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run();
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});
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return;
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}
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offset = end;
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bytesThisTick += slice.length;
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if (bytesThisTick >= BYTES_PER_TICK) {
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// Yield to allow other I/O
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buf._offset = offset;
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bytesThisTick = 0;
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setImmediate(() => {
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state.sending = false;
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run();
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});
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return;
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}
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}
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// Finished this buffer
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delete buf._offset;
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state.queue.shift();
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}
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state.sending = false;
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};
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run();
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}
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function enqueueToTunnel(connectionId, data) {
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let state = txQueues.get(connectionId);
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if (!state) {
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state = { queue: [], sending: false };
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txQueues.set(connectionId, state);
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}
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state.queue.push(data);
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// Attempt to process immediately
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if (!state.sending) {
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state.sending = false; // ensure process can start
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processTxQueue(connectionId, state);
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}
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}
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function closeAllUpstreams() {
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for (const [, s] of upstreamConns) {
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try { s.destroy(); } catch (_) {}
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}
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upstreamConns.clear();
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}
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function closeAllUdp() {
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for (const [, obj] of udpAssoc) {
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try { obj.udp4 && obj.udp4.close(); } catch (_) {}
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try { obj.udp6 && obj.udp6.close(); } catch (_) {}
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}
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udpAssoc.clear();
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}
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function ensureUdpSocketsForAssoc(connectionId) {
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if (udpAssoc.has(connectionId)) return udpAssoc.get(connectionId);
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const onMessage = (msg, rinfo) => {
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// Forward incoming datagrams to client
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writeMessage(tunnelSocket, MSG_TYPES.UDP_RECV, connectionId, buildUdpPayload(rinfo.address, rinfo.port, msg));
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};
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// Create both IPv4 and IPv6 sockets to support all targets
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const u4 = dgram.createSocket('udp4');
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const u6 = dgram.createSocket('udp6');
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u4.on('message', onMessage);
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u6.on('message', onMessage);
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u4.on('error', (err) => { /* log but keep running */ console.warn(`UDP4 error (conn ${connectionId}): ${err.message}`); });
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u6.on('error', (err) => { /* log but keep running */ console.warn(`UDP6 error (conn ${connectionId}): ${err.message}`); });
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// Bind to ephemeral ports to receive replies
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try { u4.bind(0); } catch (_) {}
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try { u6.bind(0); } catch (_) {}
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const entry = { udp4: u4, udp6: u6 };
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udpAssoc.set(connectionId, entry);
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return entry;
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}
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const server = tls.createServer(
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const clientServer = tls.createServer(
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{
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pskCallback,
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pskCallback: clientPskCallback,
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ciphers: 'PSK-AES256-GCM-SHA384:PSK-AES128-GCM-SHA256',
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},
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(socket) => {
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console.log('Proxy tunnel client connected');
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tunnelSocket = socket;
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if (clientSocket) {
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console.log('Rejecting new client connection, already have one.');
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socket.destroy();
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return;
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}
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console.log('Client connected');
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clientSocket = socket;
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socket.setNoDelay(true);
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socket.setKeepAlive(true, 30000);
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const reader = createMessageReader();
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socket.on('data', (data) => {
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reader(data, (type, connectionId, payload) => {
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if (type === MSG_TYPES.OPEN) {
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const spec = parseOpenPayload(payload);
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if (!spec) {
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console.warn(`Invalid OPEN payload for connection ${connectionId}`);
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writeMessage(tunnelSocket, MSG_TYPES.OPEN_RESULT, connectionId, buildOpenResultPayload(false));
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return;
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}
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const { host, port } = spec;
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// Create outbound TCP connection
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const upstream = net.createConnection({ host, port });
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upstream.setNoDelay(true);
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upstream.setKeepAlive(true, 30000);
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let connected = false;
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const connectTimer = setTimeout(() => {
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if (!connected) {
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upstream.destroy(new Error('Connect timeout'));
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}
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}, OUT_CONNECT_TIMEOUT);
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upstream.once('connect', () => {
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connected = true;
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clearTimeout(connectTimer);
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upstreamConns.set(connectionId, upstream);
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// Notify open success
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writeMessage(tunnelSocket, MSG_TYPES.OPEN_RESULT, connectionId, buildOpenResultPayload(true));
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});
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upstream.on('data', (chunk) => {
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// Queue data with framing and backpressure-aware sending
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enqueueToTunnel(connectionId, chunk);
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});
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const cleanup = () => {
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clearTimeout(connectTimer);
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if (upstreamConns.get(connectionId) === upstream) {
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upstreamConns.delete(connectionId);
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}
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// Drop any pending TX data for this connection
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txQueues.delete(connectionId);
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writeMessage(tunnelSocket, MSG_TYPES.CLOSE, connectionId);
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};
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upstream.on('error', (err) => {
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if (!connected) {
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clearTimeout(connectTimer);
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writeMessage(tunnelSocket, MSG_TYPES.OPEN_RESULT, connectionId, buildOpenResultPayload(false));
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} else {
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// Upstream error after established
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cleanup();
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}
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});
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upstream.on('close', () => {
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cleanup();
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});
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} else if (type === MSG_TYPES.DATA) {
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const upstream = upstreamConns.get(connectionId);
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if (upstream && !upstream.destroyed) {
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upstream.write(payload);
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}
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} else if (type === MSG_TYPES.CLOSE) {
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const upstream = upstreamConns.get(connectionId);
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if (upstream) {
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upstream.destroy();
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upstreamConns.delete(connectionId);
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}
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// UDP handling
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} else if (type === MSG_TYPES.UDP_OPEN) {
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try {
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ensureUdpSocketsForAssoc(connectionId);
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writeMessage(tunnelSocket, MSG_TYPES.UDP_OPEN_RESULT, connectionId, buildOpenResultPayload(true));
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} catch (e) {
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console.warn(`Failed to create UDP association for ${connectionId}: ${e.message}`);
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writeMessage(tunnelSocket, MSG_TYPES.UDP_OPEN_RESULT, connectionId, buildOpenResultPayload(false));
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}
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} else if (type === MSG_TYPES.UDP_SEND) {
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const parsed = parseUdpPayload(payload);
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if (!parsed) {
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console.warn(`Invalid UDP_SEND payload for ${connectionId}`);
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return;
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}
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const { host, port, data } = parsed;
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const entry = udpAssoc.get(connectionId) || ensureUdpSocketsForAssoc(connectionId);
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// Choose v6 socket if IPv6 literal detected
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const isV6 = host.includes(':');
|
||||
const sock = isV6 ? entry.udp6 : entry.udp4;
|
||||
try {
|
||||
sock.send(data, port, host);
|
||||
} catch (e) {
|
||||
console.warn(`UDP send failed (conn ${connectionId}) to ${host}:${port} - ${e.message}`);
|
||||
}
|
||||
} else if (type === MSG_TYPES.UDP_CLOSE) {
|
||||
const entry = udpAssoc.get(connectionId);
|
||||
if (entry) {
|
||||
try { entry.udp4 && entry.udp4.close(); } catch (_) {}
|
||||
try { entry.udp6 && entry.udp6.close(); } catch (_) {}
|
||||
udpAssoc.delete(connectionId);
|
||||
}
|
||||
} else {
|
||||
// ignore unknown types
|
||||
}
|
||||
});
|
||||
clientReader = createMessageReader((type, connId, data) => {
|
||||
// Forward messages from client to exit
|
||||
if (exitSocket && !exitSocket.destroyed) {
|
||||
writeMessage(exitSocket, type, connId, data);
|
||||
}
|
||||
});
|
||||
|
||||
socket.on('data', (data) => clientReader(data));
|
||||
|
||||
socket.on('close', () => {
|
||||
console.log('Proxy tunnel disconnected');
|
||||
tunnelSocket = null;
|
||||
closeAllUpstreams();
|
||||
closeAllUdp();
|
||||
console.log('Client disconnected');
|
||||
clientSocket = null;
|
||||
// When client disconnects, we can optionally close the exit connection
|
||||
// or keep it alive. For simplicity, we keep it.
|
||||
});
|
||||
|
||||
socket.on('error', (err) => {
|
||||
console.error('Tunnel socket error:', err.message);
|
||||
console.error('Client socket error:', err.message);
|
||||
});
|
||||
}
|
||||
);
|
||||
|
||||
server.listen(parseInt(options.tunnelPort, 10), options.host, () => {
|
||||
console.log(`PSK Proxy Out-Node listening on ${options.host}:${options.tunnelPort}`);
|
||||
clientServer.listen(parseInt(options.tunnelPort, 10), options.host, () => {
|
||||
console.log(`PSK Proxy Relay-Node listening for clients on ${options.host}:${options.tunnelPort}`);
|
||||
});
|
||||
|
||||
// Start connection to the exit node
|
||||
connectToExitNode();
|
||||
|
||||
process.on('SIGINT', () => {
|
||||
console.log('Shutting down...');
|
||||
try { server.close(); } catch (_) {}
|
||||
closeAllUpstreams();
|
||||
closeAllUdp();
|
||||
try { clientServer.close(); } catch (_) {}
|
||||
if (clientSocket) try { clientSocket.destroy(); } catch (_) {}
|
||||
if (exitSocket) try { exitSocket.destroy(); } catch (_) {}
|
||||
process.exit(0);
|
||||
});
|
||||
});
|
||||
Reference in New Issue
Block a user