475 lines
15 KiB
TypeScript
475 lines
15 KiB
TypeScript
import {
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IntermediatePacketCodec,
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BaseTcpTransport,
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TransportState,
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tl
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} from '@mtcute/core'
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import { connect } from 'net'
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// eslint-disable-next-line @typescript-eslint/ban-ts-comment
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// @ts-ignore
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import { normalize } from 'ip6'
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/**
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* An error has occurred while connecting to an SOCKS proxy
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*/
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export class SocksProxyConnectionError extends Error {
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readonly proxy: SocksProxySettings
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constructor(proxy: SocksProxySettings, message: string) {
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super(
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`Error while connecting to ${proxy.host}:${proxy.port}: ${message}`
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)
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this.proxy = proxy
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}
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}
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export interface SocksProxySettings {
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/**
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* Host or IP of the proxy (e.g. `proxy.example.com`, `1.2.3.4`)
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*/
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host: string
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/**
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* Port of the proxy (e.g. `8888`)
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*/
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port: number
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/**
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* Proxy authorization username, if needed
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*/
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user?: string
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/**
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* Proxy authorization password, if needed
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*/
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password?: string
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/**
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* Version of the SOCKS proxy (4 or 5)
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*
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* Defaults to `5`.
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*/
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version?: 4 | 5
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}
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function writeIpv4(ip: string, buf: Buffer, offset: number): void {
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const parts = ip.split('.')
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if (parts.length !== 4) {
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throw new Error('Invalid IPv4 address')
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}
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for (let i = 0; i < 4; i++) {
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const n = parseInt(parts[i])
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if (isNaN(n) || n < 0 || n > 255) {
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throw new Error('Invalid IPv4 address')
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}
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buf[offset + i] = n
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}
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}
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function buildSocks4ConnectRequest(
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ip: string,
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port: number,
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username = ''
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): Buffer {
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const userId = Buffer.from(username)
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const buf = Buffer.alloc(9 + userId.length)
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buf[0] = 0x04 // VER
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buf[1] = 0x01 // CMD = establish a TCP/IP stream connection
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buf.writeUInt16BE(port, 2) // DSTPORT
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writeIpv4(ip, buf, 4) // DSTIP
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userId.copy(buf, 8) // ID
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buf[8 + userId.length] = 0x00 // ID (null-termination)
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return buf
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}
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function buildSocks5Greeting(authAvailable: boolean): Buffer {
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const buf = Buffer.alloc(authAvailable ? 4 : 3)
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buf[0] = 0x05 // VER
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if (authAvailable) {
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buf[1] = 0x02 // NAUTH
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buf[2] = 0x00 // AUTH[0] = No authentication
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buf[3] = 0x02 // AUTH[1] = Username/password
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} else {
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buf[1] = 0x01 // NAUTH
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buf[2] = 0x00 // AUTH[0] = No authentication
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}
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return buf
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}
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function buildSocks5Auth(username: string, password: string) {
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const usernameBuf = Buffer.from(username)
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const passwordBuf = Buffer.from(password)
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if (usernameBuf.length > 255)
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throw new Error(`Too long username (${usernameBuf.length} > 255)`)
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if (passwordBuf.length > 255)
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throw new Error(`Too long password (${passwordBuf.length} > 255)`)
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const buf = Buffer.alloc(3 + usernameBuf.length + passwordBuf.length)
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buf[0] = 0x01 // VER of auth
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buf[1] = usernameBuf.length
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usernameBuf.copy(buf, 2)
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buf[2 + usernameBuf.length] = passwordBuf.length
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passwordBuf.copy(buf, 3 + usernameBuf.length)
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return buf
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}
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function writeIpv6(ip: string, buf: Buffer, offset: number): void {
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ip = normalize(ip)
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const parts = ip.split(':')
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if (parts.length !== 8) {
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throw new Error('Invalid IPv6 address')
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}
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for (let i = 0, j = offset; i < 8; i++, j += 2) {
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const n = parseInt(parts[i])
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if (isNaN(n) || n < 0 || n > 0xffff) {
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throw new Error('Invalid IPv6 address')
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}
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buf.writeUInt16BE(n, j)
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}
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}
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function buildSocks5Connect(ip: string, port: number, ipv6 = false): Buffer {
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const buf = Buffer.alloc(ipv6 ? 22 : 10)
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buf[0] = 0x05 // VER
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buf[1] = 0x01 // CMD = establish a TCP/IP stream connection
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buf[2] = 0x00 // RSV
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if (ipv6) {
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buf[3] = 0x04 // TYPE = IPv6
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writeIpv6(ip, buf, 4) // ADDR
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buf.writeUInt16BE(port, 20) // DSTPORT
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} else {
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buf[3] = 0x01 // TYPE = IPv4
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writeIpv4(ip, buf, 4) // ADDR
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buf.writeUInt16BE(port, 8) // DSTPORT
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}
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return buf
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}
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const SOCKS4_ERRORS: Record<number, string> = {
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0x5b: 'Request rejected or failed',
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0x5c: 'Request failed because client is not running identd',
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0x5d: "Request failed because client's identd could not confirm the user ID in the request",
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}
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const SOCKS5_ERRORS: Record<number, string> = {
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1: 'General failure',
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2: 'Connection not allowed by ruleset',
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3: 'Network unreachable',
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4: 'Host unreachable',
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5: 'Connection refused by destination host',
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6: 'TTL expired',
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7: 'Command not supported / protocol error',
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8: 'Address type not supported',
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}
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/**
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* TCP transport that connects via a SOCKS4/5 proxy.
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*/
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export abstract class BaseSocksTcpTransport extends BaseTcpTransport {
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readonly _proxy: SocksProxySettings
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constructor(proxy: SocksProxySettings) {
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super()
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if (proxy.version != null && proxy.version !== 4 && proxy.version !== 5)
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throw new SocksProxyConnectionError(
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proxy,
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`Invalid SOCKS version: ${proxy.version}`
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)
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this._proxy = proxy
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}
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connect(dc: tl.RawDcOption): void {
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if (this._state !== TransportState.Idle)
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throw new Error('Transport is not IDLE')
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if (!this.packetCodecInitialized) {
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this._packetCodec.on('error', (err) => this.emit('error', err))
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this._packetCodec.on('packet', (buf) => this.emit('message', buf))
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this.packetCodecInitialized = true
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}
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this._state = TransportState.Connecting
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this._currentDc = dc
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this._socket = connect(
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this._proxy.port,
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this._proxy.host,
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this._onProxyConnected.bind(this)
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)
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this._socket.on('error', this.handleError.bind(this))
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this._socket.on('close', this.close.bind(this))
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}
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private _onProxyConnected() {
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let packetHandler: (msg: Buffer) => void
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if (this._proxy.version === 4) {
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packetHandler = (msg) => {
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if (msg[0] !== 0x04) {
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// VER, must be 4
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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`Server returned version ${msg[0]}`
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)
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)
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return
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}
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const code = msg[1]
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this.log.debug(
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'[%s:%d] CONNECT returned code %d',
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this._proxy.host,
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this._proxy.port,
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code
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)
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if (code === 0x5a) {
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this._socket!.off('data', packetHandler)
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this._socket!.on('data', (data) =>
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this._packetCodec.feed(data)
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)
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this.handleConnect()
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} else {
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const msg =
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code in SOCKS4_ERRORS
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? SOCKS4_ERRORS[code]
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: `Unknown error code: 0x${code.toString(16)}`
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(this._proxy, msg)
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)
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}
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}
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this.log.debug(
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'[%s:%d] connected to proxy, sending CONNECT',
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this._proxy.host,
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this._proxy.port
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)
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try {
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this._socket!.write(
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buildSocks4ConnectRequest(
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this._currentDc!.ipAddress,
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this._currentDc!.port,
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this._proxy.user
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)
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)
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} catch (e) {
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this._socket!.emit('error', e)
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}
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} else {
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let state: 'greeting' | 'auth' | 'connect' = 'greeting'
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const sendConnect = () => {
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this.log.debug(
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'[%s:%d] sending CONNECT',
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this._proxy.host,
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this._proxy.port
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)
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try {
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this._socket!.write(
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buildSocks5Connect(
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this._currentDc!.ipAddress,
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this._currentDc!.port,
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this._currentDc!.ipv6
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)
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)
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state = 'connect'
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} catch (e) {
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this._socket!.emit('error', e)
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}
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}
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packetHandler = (msg) => {
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switch (state) {
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case 'greeting': {
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if (msg[0] !== 0x05) {
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// VER, must be 5
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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`Server returned version ${msg[0]}`
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)
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)
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return
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}
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const chosen = msg[1]
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this.log.debug(
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'[%s:%d] GREETING returned auth method %d',
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this._proxy.host,
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this._proxy.port,
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chosen
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)
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switch (chosen) {
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case 0x00:
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// "No authentication"
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sendConnect()
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break
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case 0x02:
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// Username/password
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if (
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!this._proxy.user ||
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!this._proxy.password
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) {
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// should not happen
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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'Authentication is required, but not provided'
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)
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)
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break
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}
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try {
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this._socket!.write(
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buildSocks5Auth(
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this._proxy.user,
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this._proxy.password
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)
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)
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state = 'auth'
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} catch (e) {
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this._socket!.emit('error', e)
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}
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break
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case 0xff:
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default:
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// "no acceptable methods were offered"
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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'Authentication is required, but not provided/supported'
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)
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)
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break
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}
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break
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}
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case 'auth':
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if (msg[0] !== 0x01) {
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// VER of auth, must be 1
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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`Server returned version ${msg[0]}`
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)
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)
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return
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}
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this.log.debug(
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'[%s:%d] AUTH returned code %d',
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this._proxy.host,
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this._proxy.port,
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msg[1]
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)
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if (msg[1] === 0x00) {
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// success
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sendConnect()
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} else {
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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`Authentication failure`
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)
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)
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}
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break
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case 'connect': {
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if (msg[0] !== 0x05) {
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// VER, must be 5
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(
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this._proxy,
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`Server returned version ${msg[0]}`
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)
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)
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return
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}
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const code = msg[1]
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this.log.debug(
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'[%s:%d] CONNECT returned code %d',
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this._proxy.host,
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this._proxy.port,
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code
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)
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if (code === 0x00) {
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// Request granted
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this._socket!.off('data', packetHandler)
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this._socket!.on('data', (data) =>
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this._packetCodec.feed(data)
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)
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this.handleConnect()
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} else {
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const msg =
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code in SOCKS5_ERRORS
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? SOCKS5_ERRORS[code]
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: `Unknown error code: 0x${code.toString(
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16
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)}`
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this._socket!.emit(
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'error',
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new SocksProxyConnectionError(this._proxy, msg)
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)
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}
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}
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}
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}
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this.log.debug(
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'[%s:%d] connected to proxy, sending GREETING',
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this._proxy.host,
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this._proxy.port
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)
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try {
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this._socket!.write(
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buildSocks5Greeting(
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!!(this._proxy.user && this._proxy.password)
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)
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)
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} catch (e) {
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this._socket!.emit('error', e)
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}
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}
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this._socket!.on('data', packetHandler)
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}
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}
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export class SocksTcpTransport extends BaseSocksTcpTransport {
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_packetCodec = new IntermediatePacketCodec()
|
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}
|