From f1d2009418370ea958ed5e7a2461bfef89e5444c Mon Sep 17 00:00:00 2001
From: Yemel Jardi <angel.jardi@gmail.com>
Date: Fri, 5 Dec 2014 11:39:30 -0300
Subject: [PATCH] Add transport/connection class

---
 index.js                     |   4 +
 lib/transport/connection.js  | 575 +++++++++++++++++++++++++++++++++++
 lib/util/buffer.js           |   6 +
 test/transport/connection.js |  41 +++
 4 files changed, 626 insertions(+)
 create mode 100644 lib/transport/connection.js
 create mode 100644 test/transport/connection.js

diff --git a/index.js b/index.js
index 627909f01..acc743798 100644
--- a/index.js
+++ b/index.js
@@ -24,6 +24,10 @@ bitcore.util.bitcoin = require('./lib/util/bitcoin');
 bitcore.util.buffer = require('./lib/util/buffer');
 bitcore.util.js = require('./lib/util/js');
 
+// transport
+bitcore.transport = {};
+bitcore.transport.Connection = require('./lib/transport/connection');
+
 // errors thrown by the library
 bitcore.errors = require('./lib/errors');
 
diff --git a/lib/transport/connection.js b/lib/transport/connection.js
new file mode 100644
index 000000000..b9495d4ff
--- /dev/null
+++ b/lib/transport/connection.js
@@ -0,0 +1,575 @@
+'use strict';
+
+var MAX_RECEIVE_BUFFER = 10000000;
+var PROTOCOL_VERSION = 70000;
+
+var Util = require('util');
+var Put = require('bufferput');
+var Buffers = require('buffers');
+var buffertools = require('buffertools');
+
+// PATCH TODO: Remove (yemel)
+Buffers.prototype.skip = function (i) {
+  if (i == 0) {
+    return;
+  } else if (i == this.length) {
+    this.buffers = [];
+    this.length = 0;
+    return;
+  }
+  var pos = this.pos(i);
+  this.buffers = this.buffers.slice(pos.buf);
+  this.buffers[0] = new Buffer(this.buffers[0].slice(pos.offset));
+  this.length -= i;
+};
+
+var networks = require('../networks');
+var Block = require('../block');
+var Transaction = require('../transaction');
+var BufferUtil = require('../util/buffer');
+var BufferReader = require('../encoding/bufferreader');
+var Hash = require('../crypto/hash');
+var Random = require('../crypto/random');
+var nonce = Random.getPseudoRandomBuffer(8);
+var EventEmitter = require('events').EventEmitter;
+
+var BIP0031_VERSION = 60000;
+
+function Connection(socket, peer, opts) {
+  this.config = opts || {};
+
+  this.network = this.config.network || networks.livenet;
+  this.socket = socket;
+  this.peer = peer;
+
+  // check for socks5 proxy options and construct a proxied socket
+  if (this.config.proxy) {
+    var Socks5Client = require('socks5-client');
+    this.socket = new Socks5Client(this.config.proxy.host, this.config.proxy.port);
+  }
+
+  // A connection is considered "active" once we have received verack
+  this.active = false;
+  // The version incoming packages are interpreted as
+  this.recvVer = 0;
+  // The version outgoing packages are sent as
+  this.sendVer = 0;
+  // The (claimed) height of the remote peer's block chain
+  this.bestHeight = 0;
+  // Is this an inbound connection?
+  this.inbound = !!this.socket.server;
+  // Have we sent a getaddr on this connection?
+  this.getaddr = false;
+
+  // Receive buffer
+  this.buffers = new Buffers();
+
+  // Starting 20 Feb 2012, Version 0.2 is obsolete
+  // This is the same behavior as the official client
+  if (new Date().getTime() > 1329696000000) {
+    this.recvVer = 209;
+    this.sendVer = 209;
+  }
+
+  this.setupHandlers();
+}
+Util.inherits(Connection, EventEmitter);
+
+Connection.prototype.open = function(callback) {
+  if (typeof callback === 'function') this.once('connect', callback);
+  this.socket.connect(this.peer.port, this.peer.host);
+  return this;
+};
+
+Connection.prototype.setupHandlers = function() {
+  this.socket.addListener('connect', this.handleConnect.bind(this));
+  this.socket.addListener('error', this.handleError.bind(this));
+  this.socket.addListener('end', this.handleDisconnect.bind(this));
+  this.socket.addListener('data', (function(data) {
+    var dumpLen = 35;
+    console.debug('[' + this.peer + '] ' +
+      'Recieved ' + data.length + ' bytes of data:');
+    console.debug('... ' + buffertools.toHex(data.slice(0, dumpLen > data.length ?
+        data.length : dumpLen)) +
+      (data.length > dumpLen ? '...' : ''));
+  }).bind(this));
+  this.socket.addListener('data', this.handleData.bind(this));
+};
+
+Connection.prototype.handleConnect = function() {
+  if (!this.inbound) {
+    this.sendVersion();
+  }
+  this.emit('connect', {
+    conn: this,
+    socket: this.socket,
+    peer: this.peer
+  });
+};
+
+Connection.prototype.handleError = function(err) {
+  if (err.errno == 110 || err.errno == 'ETIMEDOUT') {
+    console.info('connection timed out for ' + this.peer);
+  } else if (err.errno == 111 || err.errno == 'ECONNREFUSED') {
+    console.info('connection refused for ' + this.peer);
+  } else {
+    console.warn('connection with ' + this.peer + ' ' + err.toString());
+  }
+  this.emit('error', {
+    conn: this,
+    socket: this.socket,
+    peer: this.peer,
+    err: err
+  });
+};
+
+Connection.prototype.handleDisconnect = function() {
+  this.emit('disconnect', {
+    conn: this,
+    socket: this.socket,
+    peer: this.peer
+  });
+};
+
+Connection.prototype.handleMessage = function(message) {
+  if (!message) {
+    // Parser was unable to make sense of the message, drop it
+    return;
+  }
+
+  try {
+    switch (message.command) {
+      case 'version':
+        // Did we connect to ourself?
+        if (buffertools.compare(nonce, message.nonce) === 0) {
+          this.socket.end();
+          return;
+        }
+
+        if (this.inbound) {
+          this.sendVersion();
+        }
+
+        if (message.version >= 209) {
+          this.sendMessage('verack', new Buffer([]));
+        }
+        this.sendVer = Math.min(message.version, PROTOCOL_VERSION);
+        if (message.version < 209) {
+          this.recvVer = Math.min(message.version, PROTOCOL_VERSION);
+        } else {
+          // We won't start expecting a checksum until after we've received
+          // the 'verack' message.
+          this.once('verack', (function() {
+            this.recvVer = message.version;
+          }).bind(this));
+        }
+        this.bestHeight = message.start_height;
+        break;
+
+      case 'verack':
+        this.recvVer = Math.min(message.version, PROTOCOL_VERSION);
+        this.active = true;
+        break;
+
+      case 'ping':
+        if ('object' === typeof message.nonce) {
+          this.sendPong(message.nonce);
+        }
+        break;
+    }
+  } catch (e) {
+    console.err('Error while handling "' + message.command + '" message from ' +
+      this.peer + ':\n' +
+      (e.stack ? e.stack : e.toString()));
+    return;
+  }
+  this.emit(message.command, {
+    conn: this,
+    socket: this.socket,
+    peer: this.peer,
+    message: message
+  });
+};
+
+Connection.prototype.sendPong = function(nonce) {
+  this.sendMessage('pong', nonce);
+};
+
+Connection.prototype.sendVersion = function() {
+  var subversion = '/BitcoinX:0.1/';
+
+  var put = new Put();
+  put.word32le(PROTOCOL_VERSION); // version
+  put.word64le(1); // services
+  put.word64le(Math.round(new Date().getTime() / 1000)); // timestamp
+  put.pad(26); // addr_me
+  put.pad(26); // addr_you
+  put.put(nonce);
+  put.varint(subversion.length);
+  put.put(new Buffer(subversion, 'ascii'));
+  put.word32le(0);
+
+  this.sendMessage('version', put.buffer());
+};
+
+Connection.prototype.sendGetBlocks = function(starts, stop, wantHeaders) {
+  // Default value for stop is 0 to get as many blocks as possible (500)
+  stop = stop || BufferUtil.NULL_HASH;
+
+  var put = new Put();
+
+  // https://en.bitcoin.it/wiki/Protocol_specification#getblocks
+  put.word32le(this.sendVer);
+  put.varint(starts.length);
+
+  for (var i = 0; i < starts.length; i++) {
+    if (starts[i].length != 32) {
+      throw new Error('Invalid hash length');
+    }
+
+    put.put(starts[i]);
+  }
+
+  var stopBuffer = new Buffer(stop, 'binary');
+  if (stopBuffer.length != 32) {
+    throw new Error('Invalid hash length');
+  }
+
+  put.put(stopBuffer);
+
+  var command = 'getblocks';
+  if (wantHeaders)
+    command = 'getheaders';
+  this.sendMessage(command, put.buffer());
+};
+
+Connection.prototype.sendGetHeaders = function(starts, stop) {
+  this.sendGetBlocks(starts, stop, true);
+};
+
+Connection.prototype.sendGetData = function(invs) {
+  var put = new Put();
+  put.varint(invs.length);
+  for (var i = 0; i < invs.length; i++) {
+    put.word32le(invs[i].type);
+    put.put(invs[i].hash);
+  }
+  this.sendMessage('getdata', put.buffer());
+};
+
+Connection.prototype.sendGetAddr = function(invs) {
+  var put = new Put();
+  this.sendMessage('getaddr', put.buffer());
+};
+
+Connection.prototype.sendInv = function(data) {
+  if (!Array.isArray(data)) data = [data];
+  var put = new Put();
+  put.varint(data.length);
+  data.forEach(function(value) {
+    if (value instanceof Block) {
+      // Block
+      put.word32le(2); // MSG_BLOCK
+    } else {
+      // Transaction
+      put.word32le(1); // MSG_TX
+    }
+    put.put(value.getHash());
+  });
+  this.sendMessage('inv', put.buffer());
+};
+
+Connection.prototype.sendHeaders = function(headers) {
+  var put = new Put();
+  put.varint(headers.length);
+  headers.forEach(function(header) {
+    put.put(header);
+
+    // Indicate 0 transactions
+    put.word8(0);
+  });
+  this.sendMessage('headers', put.buffer());
+};
+
+Connection.prototype.sendTx = function(tx) {
+  this.sendMessage('tx', tx.serialize());
+};
+
+Connection.prototype.sendBlock = function(block, txs) {
+  var put = new Put();
+
+  // Block header
+  put.put(block.getHeader());
+
+  // List of transactions
+  put.varint(txs.length);
+  txs.forEach(function(tx) {
+    put.put(tx.serialize());
+  });
+
+  this.sendMessage('block', put.buffer());
+};
+
+Connection.prototype.sendMessage = function(command, payload) {
+  try {
+    var magic = this.network.magic;
+    var commandBuf = new Buffer(command, 'ascii');
+    if (commandBuf.length > 12) throw 'Command name too long';
+
+    var checksum;
+    if (this.sendVer >= 209) {
+      checksum = Hash.sha256sha256(payload).slice(0, 4);
+    } else {
+      checksum = new Buffer([]);
+    }
+
+    var message = new Put(); // -- HEADER --
+    message.put(magic); // magic bytes
+    message.put(commandBuf); // command name
+    message.pad(12 - commandBuf.length); // zero-padded
+    message.word32le(payload.length); // payload length
+    message.put(checksum); // checksum
+    // -- BODY --
+    message.put(payload); // payload data
+
+    var buffer = message.buffer();
+
+    console.debug('[' + this.peer + '] ' +
+      'Sending message ' + command + ' (' + payload.length + ' bytes)');
+
+    this.socket.write(buffer);
+  } catch (err) {
+    // TODO: We should catch this error one level higher in order to better
+    //       determine how to react to it. For now though, ignoring it will do.
+    console.err('Error while sending message to peer ' + this.peer + ': ' +
+      (err.stack ? err.stack : err.toString()));
+  }
+};
+
+Connection.prototype.handleData = function(data) {
+  this.buffers.push(data);
+
+  if (this.buffers.length > MAX_RECEIVE_BUFFER) {
+    console.err('Peer ' + this.peer + ' exceeded maxreceivebuffer, disconnecting.' +
+      (err.stack ? err.stack : err.toString()));
+    this.socket.destroy();
+    return;
+  }
+
+  this.processData();
+};
+
+Connection.prototype.processData = function() {
+  // If there are less than 20 bytes there can't be a message yet.
+  if (this.buffers.length < 20) return;
+
+  var magic = this.network.magic;
+  var i = 0;
+  for (;;) {
+    if (this.buffers.get(i) === magic[0] &&
+      this.buffers.get(i + 1) === magic[1] &&
+      this.buffers.get(i + 2) === magic[2] &&
+      this.buffers.get(i + 3) === magic[3]) {
+      if (i !== 0) {
+        console.debug('[' + this.peer + '] ' +
+          'Received ' + i +
+          ' bytes of inter-message garbage: ');
+        console.debug('... ' + this.buffers.slice(0, i));
+
+        this.buffers.skip(i);
+      }
+      break;
+    }
+
+    if (i > (this.buffers.length - 4)) {
+      this.buffers.skip(i);
+      return;
+    }
+    i++;
+  }
+
+  var payloadLen = (this.buffers.get(16)) +
+    (this.buffers.get(17) << 8) +
+    (this.buffers.get(18) << 16) +
+    (this.buffers.get(19) << 24);
+
+  var startPos = (this.recvVer >= 209) ? 24 : 20;
+  var endPos = startPos + payloadLen;
+
+  if (this.buffers.length < endPos) return;
+
+  var command = this.buffers.slice(4, 16).toString('ascii').replace(/\0+$/, '');
+  var payload = this.buffers.slice(startPos, endPos);
+  var checksum = (this.recvVer >= 209) ? this.buffers.slice(20, 24) : null;
+
+  console.debug('[' + this.peer + '] ' +
+    'Received message ' + command +
+    ' (' + payloadLen + ' bytes)');
+
+  if (checksum !== null) {
+    var checksumConfirm = Hash.sha256sha256(payload).slice(0, 4);
+    if (buffertools.compare(checksumConfirm, checksum) !== 0) {
+      console.err('[' + this.peer + '] ' +
+        'Checksum failed', {
+          cmd: command,
+          expected: checksumConfirm.toString('hex'),
+          actual: checksum.toString('hex')
+        });
+      return;
+    }
+  }
+
+  var message;
+  try {
+    message = this.parseMessage(command, payload);
+  } catch (e) {
+    console.err('Error while parsing message ' + command + ' from ' +
+      this.peer + ':\n' +
+      (e.stack ? e.stack : e.toString()));
+  }
+
+  if (message) {
+    this.handleMessage(message);
+  }
+
+  this.buffers.skip(endPos);
+  this.processData();
+};
+
+Connection.prototype.parseMessage = function(command, payload) {
+  var parser = new BufferReader(payload);
+
+  var data = {
+    command: command
+  };
+
+  var i;
+
+  switch (command) {
+    case 'version': // https://en.bitcoin.it/wiki/Protocol_specification#version
+      data.version = parser.readUInt32LE();
+      data.services = parser.readUInt64LEBN();
+      data.timestamp = parser.readUInt64LEBN();
+      data.addr_me = parser.read(26);
+      data.addr_you = parser.read(26);
+      data.nonce = parser.read(8);
+      data.subversion = parser.readVarintBuf();
+      data.start_height = parser.readUInt32LE();
+      break;
+
+    case 'inv':
+    case 'getdata':
+      data.count = parser.readVarintNum();
+
+      data.invs = [];
+      for (i = 0; i < data.count; i++) {
+        data.invs.push({
+          type: parser.readUInt32LE(),
+          hash: parser.read(32)
+        });
+      }
+      break;
+
+    case 'headers':
+      data.count = parser.readVarintNum();
+
+      data.headers = [];
+      for (i = 0; i < data.count; i++) {
+        var header = Block.fromBufferReader(parser);
+        data.headers.push(header);
+      }
+      break;
+
+    case 'block':
+      var block = Block.fromBufferReader(parser);
+
+      data.block = block;
+      data.version = block.version;
+      data.prev_hash = block.prev_hash;
+      data.merkle_root = block.merkle_root;
+      data.timestamp = block.timestamp;
+      data.bits = block.bits;
+      data.nonce = block.nonce;
+
+      data.txs = block.txs;
+
+      data.size = payload.length;
+      break;
+
+    case 'tx':
+      var tx = Transaction.fromBufferReader(parser);
+      return {
+        command: command,
+        version: tx.version,
+        lock_time: tx.lock_time,
+        ins: tx.ins,
+        outs: tx.outs,
+        tx: tx,
+      };
+
+    case 'getblocks':
+    case 'getheaders':
+      // parse out the version
+      data.version = parser.readUInt32LE();
+
+      // TODO: Limit block locator size?
+      // reference implementation limits to 500 results
+      var startCount = parser.readVarintNum();
+
+      data.starts = [];
+      for (i = 0; i < startCount; i++) {
+        data.starts.push(parser.read(32));
+      }
+      data.stop = parser.read(32);
+      break;
+
+    case 'addr':
+      var addrCount = parser.readVarintNum();
+
+      // Enforce a maximum number of addresses per message
+      if (addrCount > 1000) {
+        addrCount = 1000;
+      }
+
+      data.addrs = [];
+      for (i = 0; i < addrCount; i++) {
+        // TODO: Time actually depends on the version of the other peer (>=31402)
+        data.addrs.push({
+          time: parser.readUInt32LE(),
+          services: parser.readUInt64LEBN(),
+          ip: parser.read(16),
+          port: parser.readUInt16BE()
+        });
+      }
+      break;
+
+    case 'alert':
+      data.payload = parser.readVarintBuf();
+      data.signature = parser.readVarintBuf();
+      break;
+
+    case 'ping':
+      if (this.recvVer > BIP0031_VERSION) {
+        data.nonce = parser.read(8);
+      }
+      break;
+
+    case 'getaddr':
+    case 'verack':
+    case 'reject':
+      // Empty message, nothing to parse
+      break;
+
+    default:
+      console.err('Connection.parseMessage(): Command not implemented', {
+        cmd: command
+      });
+
+      // This tells the calling function not to issue an event
+      return null;
+  }
+
+  return data;
+};
+
+module.exports = Connection;
\ No newline at end of file
diff --git a/lib/util/buffer.js b/lib/util/buffer.js
index 73a60b336..a84023e69 100644
--- a/lib/util/buffer.js
+++ b/lib/util/buffer.js
@@ -2,6 +2,7 @@
 
 var buffer = require('buffer');
 var assert = require('assert');
+var buffertools = require('buffertools');
 
 var js = require('./js');
 
@@ -19,6 +20,11 @@ function equals(a, b) {
 }
 
 module.exports = {
+  NULL_HASH: buffertools.fill(new Buffer(32), 0),
+  EMPTY_BUFFER: new Buffer(0),
+  ZERO_VALUE: buffertools.fill(new Buffer(8), 0),
+  INT64_MAX: new Buffer('ffffffffffffffff', 'hex'),
+
   /**
    * Returns true if the given argument is an instance of a buffer. Tests for
    * both node's Buffer and Uint8Array
diff --git a/test/transport/connection.js b/test/transport/connection.js
new file mode 100644
index 000000000..2b52b483c
--- /dev/null
+++ b/test/transport/connection.js
@@ -0,0 +1,41 @@
+'use strict';
+
+var chai = require('chai');
+var bitcore = require('../..');
+
+var should = chai.should();
+
+var ConnectionModule = bitcore.transport.Connection;
+var Connection;
+var nop = function() {};
+
+describe.only('Connection', function() {
+  it('should initialze the main object', function() {
+    should.exist(ConnectionModule);
+  });
+  it('should be able to create class', function() {
+    Connection = ConnectionModule;
+    should.exist(Connection);
+  });
+  it('should be able to create instance', function() {
+    var mSocket = {server: null, addListener: nop},
+      mPeer;
+    var c = new Connection(mSocket, mPeer);
+    should.exist(c);
+  });
+
+  if (typeof process !== 'undefined' && process.versions) { //node-only tests
+    it('should create a proxied socket if instructed', function() {
+      var mPeer;
+      var c = new Connection(null, mPeer, {
+        proxy: { host: 'localhost', port: 9050 }
+      });
+      should.exist(c.socket);
+    });
+  };
+});
+
+
+
+
+