""" Bitmessage Protocol """ # pylint: disable=attribute-defined-outside-init, too-few-public-methods import base64 import hashlib import logging import socket import struct import time from binascii import hexlify import addresses import connectionpool import knownnodes import protocol import state from bmconfigparser import BMConfigParser from inventory import Inventory from network.advanceddispatcher import AdvancedDispatcher from network.bmobject import ( BMObject, BMObjectAlreadyHaveError, BMObjectExpiredError, BMObjectInsufficientPOWError, BMObjectInvalidDataError, BMObjectInvalidError, BMObjectUnwantedStreamError ) from network.constants import ( ADDRESS_ALIVE, MAX_MESSAGE_SIZE, MAX_OBJECT_COUNT, MAX_OBJECT_PAYLOAD_SIZE, MAX_TIME_OFFSET ) from network.dandelion import Dandelion from network.proxy import ProxyError from node import Node, Peer from objectracker import ObjectTracker, missingObjects from queues import invQueue, objectProcessorQueue, portCheckerQueue from randomtrackingdict import RandomTrackingDict logger = logging.getLogger('default') class BMProtoError(ProxyError): """A Bitmessage Protocol Base Error""" errorCodes = ("Protocol error") class BMProtoInsufficientDataError(BMProtoError): """A Bitmessage Protocol Insufficient Data Error""" errorCodes = ("Insufficient data") class BMProtoExcessiveDataError(BMProtoError): """A Bitmessage Protocol Excessive Data Error""" errorCodes = ("Too much data") class BMProto(AdvancedDispatcher, ObjectTracker): """A parser for the Bitmessage Protocol""" # pylint: disable=too-many-instance-attributes, too-many-public-methods timeOffsetWrongCount = 0 def __init__(self, address=None, sock=None): # pylint: disable=unused-argument, super-init-not-called AdvancedDispatcher.__init__(self, sock) self.isOutbound = False # packet/connection from a local IP self.local = False self.pendingUpload = RandomTrackingDict() # canonical identifier of network group self.network_group = None def bm_proto_reset(self): """Reset the bitmessage object parser""" self.magic = None self.command = None self.payloadLength = 0 self.checksum = None self.payload = None self.invalid = False self.payloadOffset = 0 self.expectBytes = protocol.Header.size self.object = None def state_bm_header(self): """Process incoming header""" self.magic, self.command, self.payloadLength, self.checksum = \ protocol.Header.unpack(self.read_buf[:protocol.Header.size]) self.command = self.command.rstrip('\x00') if self.magic != 0xE9BEB4D9: # skip 1 byte in order to sync self.set_state("bm_header", length=1) self.bm_proto_reset() logger.debug('Bad magic') if self.socket.type == socket.SOCK_STREAM: self.close_reason = "Bad magic" self.set_state("close") return False if self.payloadLength > MAX_MESSAGE_SIZE: self.invalid = True self.set_state( "bm_command", length=protocol.Header.size, expectBytes=self.payloadLength) return True def state_bm_command(self): # pylint: disable=too-many-branches """Process incoming command""" self.payload = self.read_buf[:self.payloadLength] if self.checksum != hashlib.sha512(self.payload).digest()[0:4]: logger.debug('Bad checksum, ignoring') self.invalid = True retval = True if not self.fullyEstablished and self.command not in ( "error", "version", "verack"): logger.error( 'Received command %s before connection was fully' ' established, ignoring', self.command) self.invalid = True if not self.invalid: try: retval = getattr( self, "bm_command_" + str(self.command).lower())() except AttributeError: # unimplemented command logger.debug('unimplemented command %s', self.command) except BMProtoInsufficientDataError: logger.debug('packet length too short, skipping') except BMProtoExcessiveDataError: logger.debug('too much data, skipping') except BMObjectInsufficientPOWError: logger.debug('insufficient PoW, skipping') except BMObjectInvalidDataError: logger.debug('object invalid data, skipping') except BMObjectExpiredError: logger.debug('object expired, skipping') except BMObjectUnwantedStreamError: logger.debug('object not in wanted stream, skipping') except BMObjectInvalidError: logger.debug('object invalid, skipping') except BMObjectAlreadyHaveError: logger.debug( '%(host)s:%(port)i already got object, skipping', self.destination._asdict()) except struct.error: logger.debug('decoding error, skipping') elif self.socket.type == socket.SOCK_DGRAM: # broken read, ignore pass else: logger.debug('Closing due to invalid command %s', self.command) self.close_reason = "Invalid command %s" % self.command self.set_state("close") return False if retval: self.set_state("bm_header", length=self.payloadLength) self.bm_proto_reset() # else assume the command requires a different state to follow return True def decode_payload_string(self, length): """Read and return `length` bytes from payload""" value = self.payload[self.payloadOffset:self.payloadOffset + length] self.payloadOffset += length return value def decode_payload_varint(self): """Decode a varint from the payload""" value, offset = addresses.decodeVarint( self.payload[self.payloadOffset:]) self.payloadOffset += offset return value def decode_payload_node(self): """Decode node details from the payload""" # protocol.checkIPAddress() services, host, port = self.decode_payload_content("Q16sH") if host[0:12] == '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF': host = socket.inet_ntop(socket.AF_INET, str(host[12:16])) elif host[0:6] == '\xfd\x87\xd8\x7e\xeb\x43': # Onion, based on BMD/bitcoind host = base64.b32encode(host[6:]).lower() + ".onion" else: host = socket.inet_ntop(socket.AF_INET6, str(host)) if host == "": # This can happen on Windows systems which are not 64-bit # compatible so let us drop the IPv6 address. host = socket.inet_ntop(socket.AF_INET, str(host[12:16])) return Node(services, host, port) # pylint: disable=too-many-branches, too-many-statements def decode_payload_content(self, pattern="v"): """ Decode the payload depending on pattern: L = varint indicating the length of the next array l = varint indicating the length of the next item v = varint (or array) H = uint16 I = uint32 Q = uint64 i = net_addr (without time and stream number) s = string 0-9 = length of the next item , = end of array """ # pylint: disable=inconsistent-return-statements def decode_simple(self, char="v"): """Decode the payload using one char pattern""" if char == "v": return self.decode_payload_varint() if char == "i": return self.decode_payload_node() if char == "H": self.payloadOffset += 2 return struct.unpack(">H", self.payload[ self.payloadOffset - 2:self.payloadOffset])[0] if char == "I": self.payloadOffset += 4 return struct.unpack(">I", self.payload[ self.payloadOffset - 4:self.payloadOffset])[0] if char == "Q": self.payloadOffset += 8 return struct.unpack(">Q", self.payload[ self.payloadOffset - 8:self.payloadOffset])[0] size = None isArray = False # size # iterator starting from size counting to 0 # isArray? # subpattern # position of parser in subpattern # retval (array) parserStack = [[1, 1, False, pattern, 0, []]] while True: i = parserStack[-1][3][parserStack[-1][4]] if i in "0123456789" and ( size is None or parserStack[-1][3][parserStack[-1][4] - 1] not in "lL"): try: size = size * 10 + int(i) except TypeError: size = int(i) isArray = False elif i in "Ll" and size is None: size = self.decode_payload_varint() isArray = i == "L" elif size is not None: if isArray: parserStack.append([ size, size, isArray, parserStack[-1][3][parserStack[-1][4]:], 0, [] ]) parserStack[-2][4] = len(parserStack[-2][3]) else: for j in range(parserStack[-1][4], len(parserStack[-1][3])): if parserStack[-1][3][j] not in "lL0123456789": break # pylint: disable=undefined-loop-variable parserStack.append([ size, size, isArray, parserStack[-1][3][parserStack[-1][4]:j + 1], 0, [] ]) parserStack[-2][4] += len(parserStack[-1][3]) - 1 size = None continue elif i == "s": # if parserStack[-2][2]: # parserStack[-1][5].append(self.payload[ # self.payloadOffset:self.payloadOffset + parserStack[-1][0]]) # else: parserStack[-1][5] = self.payload[ self.payloadOffset:self.payloadOffset + parserStack[-1][0]] self.payloadOffset += parserStack[-1][0] parserStack[-1][1] = 0 parserStack[-1][2] = True # del parserStack[-1] size = None elif i in "viHIQ": parserStack[-1][5].append(decode_simple( self, parserStack[-1][3][parserStack[-1][4]])) size = None else: size = None for depth in range(len(parserStack) - 1, -1, -1): parserStack[depth][4] += 1 if parserStack[depth][4] >= len(parserStack[depth][3]): parserStack[depth][1] -= 1 parserStack[depth][4] = 0 if depth > 0: if parserStack[depth][2]: parserStack[depth - 1][5].append( parserStack[depth][5]) else: parserStack[depth - 1][5].extend( parserStack[depth][5]) parserStack[depth][5] = [] if parserStack[depth][1] <= 0: if depth == 0: # we're done, at depth 0 counter is at 0 # and pattern is done parsing return parserStack[depth][5] del parserStack[-1] continue break break if self.payloadOffset > self.payloadLength: logger.debug( 'Insufficient data %i/%i', self.payloadOffset, self.payloadLength) raise BMProtoInsufficientDataError() def bm_command_error(self): """Decode an error message and log it""" err_values = self.decode_payload_content("vvlsls") fatalStatus = err_values[0] # banTime = err_values[1] # inventoryVector = err_values[2] errorText = err_values[3] logger.error( '%s:%i error: %i, %s', self.destination.host, self.destination.port, fatalStatus, errorText) return True def bm_command_getdata(self): """ Incoming request for object(s). If we have them and some other conditions are fulfilled, append them to the write queue. """ items = self.decode_payload_content("l32s") # skip? now = time.time() if now < self.skipUntil: return True for i in items: self.pendingUpload[str(i)] = now return True def _command_inv(self, dandelion=False): items = self.decode_payload_content("l32s") if len(items) > MAX_OBJECT_COUNT: logger.error( 'Too many items in %sinv message!', 'd' if dandelion else '') raise BMProtoExcessiveDataError() # ignore dinv if dandelion turned off if dandelion and not state.dandelion: return True for i in map(str, items): if i in Inventory() and not Dandelion().hasHash(i): continue if dandelion and not Dandelion().hasHash(i): Dandelion().addHash(i, self) self.handleReceivedInventory(i) return True def bm_command_inv(self): """Non-dandelion announce""" return self._command_inv(False) def bm_command_dinv(self): """Dandelion stem announce""" return self._command_inv(True) def bm_command_object(self): """Incoming object, process it""" objectOffset = self.payloadOffset nonce, expiresTime, objectType, version, streamNumber = \ self.decode_payload_content("QQIvv") self.object = BMObject( nonce, expiresTime, objectType, version, streamNumber, self.payload, self.payloadOffset) if len(self.payload) - self.payloadOffset > MAX_OBJECT_PAYLOAD_SIZE: logger.info( 'The payload length of this object is too large (%d bytes).' ' Ignoring it.', len(self.payload) - self.payloadOffset) raise BMProtoExcessiveDataError() try: self.object.checkProofOfWorkSufficient() self.object.checkEOLSanity() self.object.checkAlreadyHave() except (BMObjectExpiredError, BMObjectAlreadyHaveError, BMObjectInsufficientPOWError): BMProto.stopDownloadingObject(self.object.inventoryHash) raise try: self.object.checkStream() except BMObjectUnwantedStreamError: acceptmismatch = BMConfigParser().get( "inventory", "acceptmismatch") BMProto.stopDownloadingObject( self.object.inventoryHash, acceptmismatch) if not acceptmismatch: raise try: self.object.checkObjectByType() objectProcessorQueue.put(( self.object.objectType, buffer(self.object.data))) except BMObjectInvalidError: BMProto.stopDownloadingObject(self.object.inventoryHash, True) else: try: del missingObjects[self.object.inventoryHash] except KeyError: pass if self.object.inventoryHash in Inventory() and Dandelion().hasHash( self.object.inventoryHash): Dandelion().removeHash( self.object.inventoryHash, "cycle detection") Inventory()[self.object.inventoryHash] = ( self.object.objectType, self.object.streamNumber, buffer(self.payload[objectOffset:]), self.object.expiresTime, buffer(self.object.tag) ) self.handleReceivedObject( self.object.streamNumber, self.object.inventoryHash) invQueue.put(( self.object.streamNumber, self.object.inventoryHash, self.destination)) return True def _decode_addr(self): return self.decode_payload_content("LQIQ16sH") def bm_command_addr(self): """Incoming addresses, process them""" # pylint: disable=redefined-outer-name addresses = self._decode_addr() for seenTime, stream, _, ip, port in addresses: decodedIP = protocol.checkIPAddress(str(ip)) if stream not in state.streamsInWhichIAmParticipating: continue if ( decodedIP and time.time() - seenTime > 0 and seenTime > time.time() - ADDRESS_ALIVE and port > 0 ): peer = Peer(decodedIP, port) with knownnodes.knownNodesLock: # isnew = knownnodes.addKnownNode(stream, peer, seenTime) # since we don't track peers outside of knownnodes, # only spread if in knownnodes to prevent flood # DISABLED TO WORKAROUND FLOOD/LEAK # if isnew: # addrQueue.put(( # stream, peer, seenTime, self.destination)) return True def bm_command_portcheck(self): """Incoming port check request, queue it.""" portCheckerQueue.put(Peer(self.destination, self.peerNode.port)) return True def bm_command_ping(self): """Incoming ping, respond to it.""" self.append_write_buf(protocol.CreatePacket('pong')) return True def bm_command_pong(self): # pylint: disable=no-self-use """ Incoming pong. Ignore it. PyBitmessage pings connections after about 5 minutes of inactivity, and leaves it to the TCP stack to handle actual timeouts. So there is no need to do anything when a pong arrives. """ # nothing really return True def bm_command_verack(self): """ Incoming verack. If already sent my own verack, handshake is complete (except potentially waiting for buffers to flush), so we can continue to the main connection phase. If not sent verack yet, continue processing. """ self.verackReceived = True if not self.verackSent: return True self.set_state( "tls_init" if self.isSSL else "connection_fully_established", length=self.payloadLength, expectBytes=0) return False def bm_command_version(self): """ Incoming version. Parse and log, remember important things, like streams, bitfields, etc. """ decoded = self.decode_payload_content("IQQiiQlslv") (self.remoteProtocolVersion, self.services, self.timestamp, self.sockNode, self.peerNode, self.nonce, self.userAgent ) = decoded[:7] self.streams = decoded[7:] self.nonce = struct.pack('>Q', self.nonce) self.timeOffset = self.timestamp - int(time.time()) logger.debug('remoteProtocolVersion: %i', self.remoteProtocolVersion) logger.debug('services: 0x%08X', self.services) logger.debug('time offset: %i', self.timeOffset) logger.debug('my external IP: %s', self.sockNode.host) logger.debug( 'remote node incoming address: %s:%i', self.destination.host, self.peerNode.port) logger.debug('user agent: %s', self.userAgent) logger.debug('streams: [%s]', ','.join(map(str, self.streams))) if not self.peerValidityChecks(): # ABORT afterwards return True self.append_write_buf(protocol.CreatePacket('verack')) self.verackSent = True if not self.isOutbound: self.append_write_buf(protocol.assembleVersionMessage( self.destination.host, self.destination.port, connectionpool.BMConnectionPool().streams, True, nodeid=self.nodeid)) logger.debug( '%(host)s:%(port)i sending version', self.destination._asdict()) if ((self.services & protocol.NODE_SSL == protocol.NODE_SSL) and protocol.haveSSL(not self.isOutbound)): self.isSSL = True if not self.verackReceived: return True self.set_state( "tls_init" if self.isSSL else "connection_fully_established", length=self.payloadLength, expectBytes=0) return False # pylint: disable=too-many-return-statements def peerValidityChecks(self): """Check the validity of the peer""" if self.remoteProtocolVersion < 3: self.append_write_buf(protocol.assembleErrorMessage( errorText="Your is using an old protocol. Closing connection.", fatal=2)) logger.debug( 'Closing connection to old protocol version %s, node: %s', self.remoteProtocolVersion, self.destination) return False if self.timeOffset > MAX_TIME_OFFSET: self.append_write_buf(protocol.assembleErrorMessage( errorText="Your time is too far in the future" " compared to mine. Closing connection.", fatal=2)) logger.info( "%s's time is too far in the future (%s seconds)." " Closing connection to it.", self.destination, self.timeOffset) BMProto.timeOffsetWrongCount += 1 return False elif self.timeOffset < -MAX_TIME_OFFSET: self.append_write_buf(protocol.assembleErrorMessage( errorText="Your time is too far in the past compared to mine." " Closing connection.", fatal=2)) logger.info( "%s's time is too far in the past (timeOffset %s seconds)." " Closing connection to it.", self.destination, self.timeOffset) BMProto.timeOffsetWrongCount += 1 return False else: BMProto.timeOffsetWrongCount = 0 if not self.streams: self.append_write_buf(protocol.assembleErrorMessage( errorText="We don't have shared stream interests." " Closing connection.", fatal=2)) logger.debug( 'Closed connection to %s because there is no overlapping' ' interest in streams.', self.destination) return False if self.destination in connectionpool.BMConnectionPool().inboundConnections: try: if not protocol.checkSocksIP(self.destination.host): self.append_write_buf(protocol.assembleErrorMessage( errorText="Too many connections from your IP." " Closing connection.", fatal=2)) logger.debug( 'Closed connection to %s because we are already' ' connected to that IP.', self.destination) return False except Exception: pass if not self.isOutbound: # incoming from a peer we're connected to as outbound, # or server full report the same error to counter deanonymisation if ( Peer(self.destination.host, self.peerNode.port) in connectionpool.BMConnectionPool().inboundConnections or len(connectionpool.BMConnectionPool()) > BMConfigParser().safeGetInt( 'bitmessagesettings', 'maxtotalconnections') + BMConfigParser().safeGetInt( 'bitmessagesettings', 'maxbootstrapconnections') ): self.append_write_buf(protocol.assembleErrorMessage( errorText="Server full, please try again later.", fatal=2)) logger.debug( 'Closed connection to %s due to server full' ' or duplicate inbound/outbound.', self.destination) return False if connectionpool.BMConnectionPool().isAlreadyConnected( self.nonce): self.append_write_buf(protocol.assembleErrorMessage( errorText="I'm connected to myself. Closing connection.", fatal=2)) logger.debug( "Closed connection to %s because I'm connected to myself.", self.destination) return False return True @staticmethod def stopDownloadingObject(hashId, forwardAnyway=False): """Stop downloading an object""" for connection in connectionpool.BMConnectionPool().connections(): try: del connection.objectsNewToMe[hashId] except KeyError: pass if not forwardAnyway: try: with connection.objectsNewToThemLock: del connection.objectsNewToThem[hashId] except KeyError: pass try: del missingObjects[hashId] except KeyError: pass def handle_close(self): """Handle close""" self.set_state("close") if not (self.accepting or self.connecting or self.connected): # already disconnected return try: logger.debug( '%s:%i: closing, %s', self.destination.host, self.destination.port, self.close_reason) except AttributeError: try: logger.debug( '%(host)s:%(port)i: closing', self.destination._asdict()) except AttributeError: logger.debug('Disconnected socket closing') AdvancedDispatcher.handle_close(self) class BMStringParser(BMProto): """ A special case of BMProto used by objectProcessor to send ACK """ def __init__(self): super(BMStringParser, self).__init__() self.destination = Peer('127.0.0.1', 8444) self.payload = None ObjectTracker.__init__(self) def send_data(self, data): """Send object given by the data string""" # This class is introduced specially for ACK sending, please # change log strings if you are going to use it for something else self.bm_proto_reset() self.payload = data try: self.bm_command_object() except BMObjectAlreadyHaveError: pass # maybe the same msg received on different nodes except BMObjectExpiredError: logger.debug( 'Sending ACK failure (expired): %s', hexlify(data)) except Exception as e: logger.debug( 'Exception of type %s while sending ACK', type(e), exc_info=True)