'use strict';var net=require('net'),util=require('util'),DNS=require('dns'),log=function(){},info=function(){},errorLog=console.error.bind(console),SOCKS_VERSION5=5,SOCKS_VERSION4=4,USERPASS,AUTHENTICATION={NOAUTH:0x00,GSSAPI:0x01,USERPASS:0x02,NONE:0xFF},REQUEST_CMD={CONNECT:0x01,BIND:0x02,UDP_ASSOCIATE:0x03},ATYP={IP_V4:0x01,DNS:0x03,IP_V6:0x04},Address={read:function(buffer,offset){if(buffer[offset]==ATYP.IP_V4){return util.format('%s.%s.%s.%s',buffer[offset+1],buffer[offset+2],buffer[offset+3],buffer[offset+4])}else if(buffer[offset]==ATYP.DNS){return buffer.toString('utf8',offset+2,offset+2+buffer[offset+1])}else if(buffer[offset]==ATYP.IP_V6){return buffer.slice(buffer[offset+1],buffer[offset+1+16])}},sizeOf:function(buffer,offset){if(buffer[offset]==ATYP.IP_V4){return 4}else if(buffer[offset]==ATYP.DNS){return buffer[offset+1]}else if(buffer[offset]==ATYP.IP_V6){return 16}}},Port={read:function(buffer,offset){if(buffer[offset]==ATYP.IP_V4){return buffer.readUInt16BE(8)}else if(buffer[offset]==ATYP.DNS){return buffer.readUInt16BE(5+buffer[offset+1])}else if(buffer[offset]==ATYP.IP_V6){return buffer.readUInt16BE(20)}},};function createSocksServer(cb,userpass){USERPASS=userpass;var socksServer=net.createServer();socksServer.on('listening',function(){var address=socksServer.address();console.log('listening %s:%d',address.address,address.port)});socksServer.on('connection',function(socket){info('CONNECTED %s:%d',socket.remoteAddress,socket.remotePort);initSocksConnection.bind(socket)(cb)});return socksServer}function initSocksConnection(on_accept){this.on('error',function(e){errorLog('%j',e)});this.handshake=handshake.bind(this);this.on_accept=on_accept;this.once('data',this.handshake)}function handshake(chunk){if(chunk[0]==SOCKS_VERSION5){this.socksVersion=SOCKS_VERSION5;this.handshake5=handshake5.bind(this);this.handshake5(chunk)}else if(chunk[0]==SOCKS_VERSION4){this.socksVersion=SOCKS_VERSION4;this.handshake4=handshake4.bind(this);this.handshake4(chunk)}else{errorLog('handshake: wrong socks version: %d',chunk[0]);this.end()}}function handshake5(chunk){var method_count=0;if(chunk[0]!=SOCKS_VERSION5){errorLog('socks5 handshake: wrong socks version: %d',chunk[0]);this.end();return}method_count=chunk[1];this.auth_methods=[];for(var i=2;i<method_count+2;i++){this.auth_methods.push(chunk[i])}log('Supported auth methods: %j',this.auth_methods);var resp=new Buffer(2);resp[0]=0x05;if(USERPASS){if(this.auth_methods.indexOf(AUTHENTICATION.USERPASS)>-1){log('Handing off to handleAuthRequest');this.handleAuthRequest=handleAuthRequest.bind(this);this.once('data',this.handleAuthRequest);resp[1]=AUTHENTICATION.USERPASS;this.write(resp)}else{errorLog('Unsuported authentication method -- disconnecting');resp[1]=0xFF;this.end(resp)}}else if(this.auth_methods.indexOf(AUTHENTICATION.NOAUTH)>-1){log('Handing off to handleConnRequest');this.handleConnRequest=handleConnRequest.bind(this);this.once('data',this.handleConnRequest);resp[1]=AUTHENTICATION.NOAUTH;this.write(resp)}else{errorLog('Unsuported authentication method -- disconnecting');resp[1]=0xFF;this.end(resp)}}function handshake4(chunk){var cmd=chunk[1],address,port,uid;if(chunk[0]!==SOCKS_VERSION4){this.end(new Buffer([0x00,0x5b]));errorLog('socks4 handleConnRequest: wrong socks version: %d',chunk[0]);return}port=chunk.readUInt16BE(2);if((chunk[4]==0&&chunk[5]==chunk[6]==0)&&(chunk[7]!=0)){var it=0;uid='';for(it=0;it<1024;it++){uid+=chunk[8+it];if(chunk[8+it]==0x00)break}address='';if(chunk[8+it]==0x00){for(it++;it<2048;it++){address+=chunk[8+it];if(chunk[8+it]==0x00)break}}if(chunk[8+it]==0x00){DNS.lookup(address,function(err,ip,family){if(err){errorLog(err+',socks4a dns lookup failed');this.end(new Buffer([0x00,0x5b]));return}else{this.socksAddress=ip;this.socksPort=port;this.socksUid=uid;log('socks4a Request: type: %d -- to: %s:%d:%s',cmd,address,port,uid);if(cmd==REQUEST_CMD.CONNECT){this.request=chunk;this.on_accept(this,port,ip,proxyReady4.bind(this))}else{this.end(new Buffer([0x00,0x5b]));return}}})}else{this.end(new Buffer([0x00,0x5b]));return}}else{address=util.format('%s.%s.%s.%s',chunk[4],chunk[5],chunk[6],chunk[7]);uid='';for(it=0;it<1024;it++){uid+=chunk[8+it];if(chunk[8+it]==0x00)break}this.socksAddress=address;this.socksPort=port;this.socksUid=uid;log('socks4 Request: type: %d -- to: %s:%d:%s',cmd,address,port,uid);if(cmd==REQUEST_CMD.CONNECT){this.request=chunk;this.on_accept(this,port,address,proxyReady4.bind(this))}else{this.end(new Buffer([0x00,0x5b]));return}}}function handleAuthRequest(chunk){var username,password;if(chunk[0]!==1){this.end(new Buffer([0x01,0x01]));errorLog('socks5 handleAuthRequest: wrong socks version: %d',chunk[0]);return}try{var na=[],pa=[],ni,pi;for(ni=2;ni<(2+chunk[1]);ni++)na.push(chunk[ni]);username=new Buffer(na).toString('utf8');for(pi=ni+1;pi<(ni+1+chunk[ni]);pi++)pa.push(chunk[pi]);password=new Buffer(pa).toString('utf8')}catch(e){this.end(new Buffer([0x01,0x01]));errorLog('socks5 handleAuthRequest: username/password '+e);return}if(USERPASS&&USERPASS.username===username&&USERPASS.password===password){log('Handing off to handleConnRequest');this.handleConnRequest=handleConnRequest.bind(this);this.once('data',this.handleConnRequest);this.write(new Buffer([0x01,0x00]))}else{this.end(new Buffer([0x01,0x01]));errorLog('socks5 handleConnRequest: wrong socks version: %d',chunk[0]);return}}function handleConnRequest(chunk){var cmd=chunk[1],address,port,offset=3;if(chunk[0]!==SOCKS_VERSION5){this.end(new Buffer([0x05,0x01]));errorLog('socks5 handleConnRequest: wrong socks version: %d',chunk[0]);return}try{address=Address.read(chunk,3);port=Port.read(chunk,3)}catch(e){errorLog('socks5 handleConnRequest: Address.read '+e);return}log('socks5 Request: type: %d -- to: %s:%d',chunk[1],address,port);if(cmd==REQUEST_CMD.CONNECT){this.request=chunk;this.on_accept(this,port,address,proxyReady5.bind(this))}else{this.end(new Buffer([0x05,0x01]));return}}function proxyReady5(){log('Indicating to the client that the proxy is ready');var resp=new Buffer(this.request.length);this.request.copy(resp);resp[0]=SOCKS_VERSION5;resp[1]=0x00;resp[2]=0x00;this.write(resp);log('socks5 Connected to: %s:%d',Address.read(resp,3),resp.readUInt16BE(resp.length-2))}function proxyReady4(){log('Indicating to the client that the proxy is ready');var resp=new Buffer(8);resp[0]=0x00;resp[1]=0x5a;resp.writeUInt16BE(this.socksPort,2);var ips=this.socksAddress.split('.');resp.writeUInt8(parseInt(ips[0]),4);resp.writeUInt8(parseInt(ips[1]),5);resp.writeUInt8(parseInt(ips[2]),6);resp.writeUInt8(parseInt(ips[3]),7);this.write(resp);log('socks4 Connected to: %s:%d:%s',this.socksAddress,this.socksPort,this.socksUid)}module.exports={createServer:createSocksServer};