""" TCP protocol handler """ # pylint: disable=too-many-ancestors import l10n import logging import math import random import socket import time import addresses import asyncore_pollchoose as asyncore import connectionpool import helper_random import knownnodes import protocol import state from bmconfigparser import BMConfigParser from helper_random import randomBytes from inventory import Inventory from network.advanceddispatcher import AdvancedDispatcher from network.assemble import assemble_addr from network.bmproto import BMProto from network.constants import MAX_OBJECT_COUNT from network.dandelion import Dandelion from network.objectracker import ObjectTracker from network.socks4a import Socks4aConnection from network.socks5 import Socks5Connection from network.tls import TLSDispatcher from node import Peer from queues import invQueue, receiveDataQueue, UISignalQueue from tr import _translate logger = logging.getLogger('default') maximumAgeOfNodesThatIAdvertiseToOthers = 10800 #: Equals three hours maximumTimeOffsetWrongCount = 3 #: Connections with wrong time offset class TCPConnection(BMProto, TLSDispatcher): # pylint: disable=too-many-instance-attributes """ .. todo:: Look to understand and/or fix the non-parent-init-called """ def __init__(self, address=None, sock=None): BMProto.__init__(self, address=address, sock=sock) self.verackReceived = False self.verackSent = False self.streams = [0] self.fullyEstablished = False self.connectedAt = 0 self.skipUntil = 0 if address is None and sock is not None: self.destination = Peer(*sock.getpeername()) self.isOutbound = False TLSDispatcher.__init__(self, sock, server_side=True) self.connectedAt = time.time() logger.debug( 'Received connection from %s:%i', self.destination.host, self.destination.port) self.nodeid = randomBytes(8) elif address is not None and sock is not None: TLSDispatcher.__init__(self, sock, server_side=False) self.isOutbound = True logger.debug( 'Outbound proxy connection to %s:%i', self.destination.host, self.destination.port) else: self.destination = address self.isOutbound = True self.create_socket( socket.AF_INET6 if ":" in address.host else socket.AF_INET, socket.SOCK_STREAM) self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) TLSDispatcher.__init__(self, sock, server_side=False) self.connect(self.destination) logger.debug( 'Connecting to %s:%i', self.destination.host, self.destination.port) try: self.local = ( protocol.checkIPAddress( protocol.encodeHost(self.destination.host), True) and not protocol.checkSocksIP(self.destination.host) ) except socket.error: # it's probably a hostname pass self.network_group = protocol.network_group(self.destination.host) ObjectTracker.__init__(self) # pylint: disable=non-parent-init-called self.bm_proto_reset() self.set_state("bm_header", expectBytes=protocol.Header.size) def antiIntersectionDelay(self, initial=False): """ This is a defense against the so called intersection attacks. It is called when you notice peer is requesting non-existing objects, or right after the connection is established. It will estimate how long an object will take to propagate across the network, and skip processing "getdata" requests until then. This means an attacker only has one shot per IP to perform the attack. """ # estimated time for a small object to propagate across the # whole network max_known_nodes = max( len(knownnodes.knownNodes[x]) for x in knownnodes.knownNodes) delay = math.ceil(math.log(max_known_nodes + 2, 20)) * ( 0.2 + invQueue.queueCount / 2.0) # take the stream with maximum amount of nodes # +2 is to avoid problems with log(0) and log(1) # 20 is avg connected nodes count # 0.2 is avg message transmission time if delay > 0: if initial: self.skipUntil = self.connectedAt + delay if self.skipUntil > time.time(): logger.debug( 'Initial skipping processing getdata for %.2fs', self.skipUntil - time.time()) else: logger.debug( 'Skipping processing getdata due to missing object' ' for %.2fs', delay) self.skipUntil = time.time() + delay def checkTimeOffsetNotification(self): """ Check if we have connected to too many nodes which have too high time offset from us """ if BMProto.timeOffsetWrongCount > \ maximumTimeOffsetWrongCount and \ not self.fullyEstablished: UISignalQueue.put(( 'updateStatusBar', _translate( "MainWindow", "The time on your computer, %1, may be wrong. " "Please verify your settings." ).arg(l10n.formatTimestamp()))) def state_connection_fully_established(self): """ State after the bitmessage protocol handshake is completed (version/verack exchange, and if both side support TLS, the TLS handshake as well). """ self.set_connection_fully_established() self.set_state("bm_header") self.bm_proto_reset() return True def set_connection_fully_established(self): """Initiate inventory synchronisation.""" if not self.isOutbound and not self.local: state.clientHasReceivedIncomingConnections = True UISignalQueue.put(('setStatusIcon', 'green')) UISignalQueue.put(( 'updateNetworkStatusTab', (self.isOutbound, True, self.destination) )) self.antiIntersectionDelay(True) self.fullyEstablished = True # The connection having host suitable for knownnodes if self.isOutbound or not self.local and not state.socksIP: knownnodes.increaseRating(self.destination) knownnodes.addKnownNode( self.streams, self.destination, time.time()) Dandelion().maybeAddStem(self) self.sendAddr() self.sendBigInv() def sendAddr(self): """Send a partial list of known addresses to peer.""" # We are going to share a maximum number of 1000 addrs (per overlapping # stream) with our peer. 500 from overlapping streams, 250 from the # left child stream, and 250 from the right child stream. maxAddrCount = BMConfigParser().safeGetInt( "bitmessagesettings", "maxaddrperstreamsend", 500) templist = [] addrs = {} for stream in self.streams: with knownnodes.knownNodesLock: for n, s in enumerate((stream, stream * 2, stream * 2 + 1)): nodes = knownnodes.knownNodes.get(s) if not nodes: continue # only if more recent than 3 hours # and having positive or neutral rating filtered = [ (k, v) for k, v in nodes.iteritems() if v["lastseen"] > int(time.time()) - maximumAgeOfNodesThatIAdvertiseToOthers and v["rating"] >= 0 and len(k.host) <= 22 ] # sent 250 only if the remote isn't interested in it elemCount = min( len(filtered), maxAddrCount / 2 if n else maxAddrCount) addrs[s] = helper_random.randomsample(filtered, elemCount) for substream in addrs: for peer, params in addrs[substream]: templist.append((substream, peer, params["lastseen"])) if templist: self.append_write_buf(assemble_addr(templist)) def sendBigInv(self): """ Send hashes of all inventory objects, chunked as the protocol has a per-command limit. """ def sendChunk(): """Send one chunk of inv entries in one command""" if objectCount == 0: return logger.debug( 'Sending huge inv message with %i objects to just this' ' one peer', objectCount) self.append_write_buf(protocol.CreatePacket( 'inv', addresses.encodeVarint(objectCount) + payload)) # Select all hashes for objects in this stream. bigInvList = {} for stream in self.streams: # may lock for a long time, but I think it's better than # thousands of small locks with self.objectsNewToThemLock: for objHash in Inventory().unexpired_hashes_by_stream(stream): # don't advertise stem objects on bigInv if Dandelion().hasHash(objHash): continue bigInvList[objHash] = 0 objectCount = 0 payload = b'' # Now let us start appending all of these hashes together. # They will be sent out in a big inv message to our new peer. for obj_hash, _ in bigInvList.items(): payload += obj_hash objectCount += 1 # Remove -1 below when sufficient time has passed for users to # upgrade to versions of PyBitmessage that accept inv with 50,000 # items if objectCount >= MAX_OBJECT_COUNT - 1: sendChunk() payload = b'' objectCount = 0 # flush sendChunk() def handle_connect(self): """Callback for TCP connection being established.""" try: AdvancedDispatcher.handle_connect(self) except socket.error as e: # pylint: disable=protected-access if e.errno in asyncore._DISCONNECTED: logger.debug( '%s:%i: Connection failed: %s', self.destination.host, self.destination.port, e) return self.nodeid = randomBytes(8) self.append_write_buf( protocol.assembleVersionMessage( self.destination.host, self.destination.port, connectionpool.BMConnectionPool().streams, False, nodeid=self.nodeid)) self.connectedAt = time.time() receiveDataQueue.put(self.destination) def handle_read(self): """Callback for reading from a socket""" TLSDispatcher.handle_read(self) receiveDataQueue.put(self.destination) def handle_write(self): """Callback for writing to a socket""" TLSDispatcher.handle_write(self) def handle_close(self): """Callback for connection being closed.""" host_is_global = self.isOutbound or not self.local and not state.socksIP if self.fullyEstablished: UISignalQueue.put(( 'updateNetworkStatusTab', (self.isOutbound, False, self.destination) )) if host_is_global: knownnodes.addKnownNode( self.streams, self.destination, time.time()) Dandelion().maybeRemoveStem(self) else: self.checkTimeOffsetNotification() if host_is_global: knownnodes.decreaseRating(self.destination) BMProto.handle_close(self) class Socks5BMConnection(Socks5Connection, TCPConnection): """SOCKS5 wrapper for TCP connections""" def __init__(self, address): Socks5Connection.__init__(self, address=address) TCPConnection.__init__(self, address=address, sock=self.socket) self.set_state("init") def state_proxy_handshake_done(self): """ State when SOCKS5 connection succeeds, we need to send a Bitmessage handshake to peer. """ Socks5Connection.state_proxy_handshake_done(self) self.nodeid = randomBytes(8) self.append_write_buf( protocol.assembleVersionMessage( self.destination.host, self.destination.port, connectionpool.BMConnectionPool().streams, False, nodeid=self.nodeid)) self.set_state("bm_header", expectBytes=protocol.Header.size) return True class Socks4aBMConnection(Socks4aConnection, TCPConnection): """SOCKS4a wrapper for TCP connections""" def __init__(self, address): Socks4aConnection.__init__(self, address=address) TCPConnection.__init__(self, address=address, sock=self.socket) self.set_state("init") def state_proxy_handshake_done(self): """ State when SOCKS4a connection succeeds, we need to send a Bitmessage handshake to peer. """ Socks4aConnection.state_proxy_handshake_done(self) self.nodeid = randomBytes(8) self.append_write_buf( protocol.assembleVersionMessage( self.destination.host, self.destination.port, connectionpool.BMConnectionPool().streams, False, nodeid=self.nodeid)) self.set_state("bm_header", expectBytes=protocol.Header.size) return True def bootstrap(connection_class): """Make bootstrapper class for connection type (connection_class)""" class Bootstrapper(connection_class): """Base class for bootstrappers""" _connection_base = connection_class def __init__(self, host, port): self._connection_base.__init__(self, Peer(host, port)) self.close_reason = self._succeed = False def bm_command_addr(self): """ Got addr message - the bootstrap succeed. Let BMProto process the addr message and switch state to 'close' """ BMProto.bm_command_addr(self) self._succeed = True self.close_reason = "Thanks for bootstrapping!" self.set_state("close") def set_connection_fully_established(self): """Only send addr here""" # pylint: disable=attribute-defined-outside-init self.fullyEstablished = True self.sendAddr() def handle_close(self): """ After closing the connection switch knownnodes.knownNodesActual back to False if the bootstrapper failed. """ BMProto.handle_close(self) if not self._succeed: knownnodes.knownNodesActual = False return Bootstrapper class TCPServer(AdvancedDispatcher): """TCP connection server for Bitmessage protocol""" def __init__(self, host='127.0.0.1', port=8444): if not hasattr(self, '_map'): AdvancedDispatcher.__init__(self) self.create_socket(socket.AF_INET, socket.SOCK_STREAM) self.set_reuse_addr() for attempt in range(50): try: if attempt > 0: logger.warning('Failed to bind on port %s', port) port = random.randint(32767, 65535) self.bind((host, port)) except socket.error as e: if e.errno in (asyncore.EADDRINUSE, asyncore.WSAEADDRINUSE): continue else: if attempt > 0: logger.warning('Setting port to %s', port) BMConfigParser().set( 'bitmessagesettings', 'port', str(port)) BMConfigParser().save() break self.destination = Peer(host, port) self.bound = True self.listen(5) def is_bound(self): """Is the socket bound?""" try: return self.bound except AttributeError: return False def handle_accept(self): """Incoming connection callback""" try: sock = self.accept()[0] except (TypeError, IndexError): return state.ownAddresses[Peer(*sock.getsockname())] = True if ( len(connectionpool.BMConnectionPool()) > BMConfigParser().safeGetInt( 'bitmessagesettings', 'maxtotalconnections') + BMConfigParser().safeGetInt( 'bitmessagesettings', 'maxbootstrapconnections') + 10 ): # 10 is a sort of buffer, in between it will go through # the version handshake and return an error to the peer logger.warning("Server full, dropping connection") sock.close() return try: connectionpool.BMConnectionPool().addConnection( TCPConnection(sock=sock)) except socket.error: pass