import base64 import hashlib import random import socket import struct import time from bmconfigparser import BMConfigParser from debug import logger from inventory import Inventory import knownnodes from network.advanceddispatcher import AdvancedDispatcher from network.dandelion import Dandelion from network.bmobject import BMObject, BMObjectInsufficientPOWError, BMObjectInvalidDataError, \ BMObjectExpiredError, BMObjectUnwantedStreamError, BMObjectInvalidError, BMObjectAlreadyHaveError import network.connectionpool from network.node import Node from network.objectracker import ObjectTracker from network.proxy import Proxy, ProxyError, GeneralProxyError import addresses from queues import objectProcessorQueue, portCheckerQueue, invQueue, addrQueue import shared import state import protocol class BMProtoError(ProxyError): errorCodes = ("Protocol error") class BMProtoInsufficientDataError(BMProtoError): errorCodes = ("Insufficient data") class BMProtoExcessiveDataError(BMProtoError): errorCodes = ("Too much data") class BMProto(AdvancedDispatcher, ObjectTracker): # ~1.6 MB which is the maximum possible size of an inv message. maxMessageSize = 1600100 # 2**18 = 256kB is the maximum size of an object payload maxObjectPayloadSize = 2**18 # protocol specification says max 1000 addresses in one addr command maxAddrCount = 1000 # protocol specification says max 50000 objects in one inv command maxObjectCount = 50000 # address is online if online less than this many seconds ago addressAlive = 10800 # maximum time offset maxTimeOffset = 3600 def __init__(self, address=None, sock=None): AdvancedDispatcher.__init__(self, sock) self.isOutbound = False # packet/connection from a local IP self.local = False def bm_proto_reset(self): 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): 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 > BMProto.maxMessageSize: self.invalid = True self.set_state("bm_command", length=protocol.Header.size, expectBytes=self.payloadLength) return True def state_bm_command(self): 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("%s:%i already got object, skipping", self.destination.host, self.destination.port) except struct.error: logger.debug("decoding error, skipping") elif self.socket.type == socket.SOCK_DGRAM: # broken read, ignore pass else: #print "Skipping command %s due to invalid data" % (self.command) 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): value = self.payload[self.payloadOffset:self.payloadOffset+length] self.payloadOffset += length return value def decode_payload_varint(self): value, offset = addresses.decodeVarint(self.payload[self.payloadOffset:]) self.payloadOffset += offset return value def decode_payload_node(self): 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) def decode_payload_content(self, pattern = "v"): # 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 def decode_simple(self, char="v"): 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, []]] #try: # sys._getframe(200) # logger.error("Stack depth warning, pattern: %s", pattern) # return #except ValueError: # pass 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() if i == "L": isArray = True else: isArray = False 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 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): fatalStatus, banTime, inventoryVector, errorText = self.decode_payload_content("vvlsls") logger.error("%s:%i error: %i, %s", self.destination.host, self.destination.port, fatalStatus, errorText) return True def bm_command_getdata(self): items = self.decode_payload_content("l32s") # skip? if time.time() < self.skipUntil: return True #TODO make this more asynchronous random.shuffle(items) for i in map(str, items): if Dandelion().hasHash(i) and \ self != Dandelion().objectChildStem(i): self.antiIntersectionDelay() logger.info('%s asked for a stem object we didn\'t offer to it.', self.destination) break else: try: self.append_write_buf(protocol.CreatePacket('object', Inventory()[i].payload)) except KeyError: self.antiIntersectionDelay() logger.info('%s asked for an object we don\'t have.', self.destination) break # I think that aborting after the first missing/stem object is more secure # when using random reordering, as the recipient won't know exactly which objects we refuse to deliver return True def _command_inv(self, dandelion=False): items = self.decode_payload_content("l32s") if len(items) >= BMProto.maxObjectCount: logger.error("Too many items in %sinv message!", "d" if dandelion else "") raise BMProtoExcessiveDataError() else: pass # 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): return self._command_inv(False) def bm_command_dinv(self): """ Dandelion stem announce """ return self._command_inv(True) def bm_command_object(self): 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 > BMProto.maxObjectPayloadSize: logger.info('The payload length of this object is too large (%s bytes). Ignoring it.' % len(self.payload) - self.payloadOffset) raise BMProtoExcessiveDataError() try: self.object.checkProofOfWorkSufficient() self.object.checkEOLSanity() self.object.checkAlreadyHave() except (BMObjectExpiredError, BMObjectAlreadyHaveError, BMObjectInsufficientPOWError) as e: BMProto.stopDownloadingObject(self.object.inventoryHash) raise e try: self.object.checkStream() except (BMObjectUnwantedStreamError,) as e: BMProto.stopDownloadingObject(self.object.inventoryHash, BMConfigParser().get("inventory", "acceptmismatch")) if not BMConfigParser().get("inventory", "acceptmismatch"): raise e try: self.object.checkObjectByType() objectProcessorQueue.put((self.object.objectType, buffer(self.object.data))) except BMObjectInvalidError as e: BMProto.stopDownloadingObject(self.object.inventoryHash, True) else: try: del state.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): addresses = self._decode_addr() for i in addresses: seenTime, stream, services, ip, port = i decodedIP = protocol.checkIPAddress(str(ip)) if stream not in state.streamsInWhichIAmParticipating: continue if decodedIP is not False and seenTime > time.time() - BMProto.addressAlive: peer = state.Peer(decodedIP, port) try: if knownnodes.knownNodes[stream][peer]["lastseen"] > seenTime: continue except KeyError: pass if len(knownnodes.knownNodes[stream]) < int(BMConfigParser().get("knownnodes", "maxnodes")): with knownnodes.knownNodesLock: try: knownnodes.knownNodes[stream][peer]["lastseen"] = seenTime except (TypeError, KeyError): knownnodes.knownNodes[stream][peer] = { "lastseen": seenTime, "rating": 0, "self": False, } addrQueue.put((stream, peer, self.destination)) return True def bm_command_portcheck(self): portCheckerQueue.put(state.Peer(self.destination, self.peerNode.port)) return True def bm_command_ping(self): self.append_write_buf(protocol.CreatePacket('pong')) return True def bm_command_pong(self): # nothing really return True def bm_command_verack(self): self.verackReceived = True if self.verackSent: if self.isSSL: self.set_state("tls_init", length=self.payloadLength, expectBytes=0) return False self.set_state("connection_fully_established", length=self.payloadLength, expectBytes=0) return False return True def bm_command_version(self): self.remoteProtocolVersion, self.services, self.timestamp, self.sockNode, self.peerNode, self.nonce, \ self.userAgent, self.streams = self.decode_payload_content("IQQiiQlsLv") 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.timestamp - int(time.time())) 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(): # TODO ABORT return True #shared.connectedHostsList[self.destination] = self.streams[0] 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, \ network.connectionpool.BMConnectionPool().streams, True, nodeid=self.nodeid)) #print "%s:%i: Sending version" % (self.destination.host, self.destination.port) if ((self.services & protocol.NODE_SSL == protocol.NODE_SSL) and protocol.haveSSL(not self.isOutbound)): self.isSSL = True if self.verackReceived: if self.isSSL: self.set_state("tls_init", length=self.payloadLength, expectBytes=0) return False self.set_state("connection_fully_established", length=self.payloadLength, expectBytes=0) return False return True def peerValidityChecks(self): if self.remoteProtocolVersion < 3: self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="Your is using an old protocol. Closing connection.")) logger.debug ('Closing connection to old protocol version %s, node: %s', str(self.remoteProtocolVersion), str(self.destination)) return False if self.timeOffset > BMProto.maxTimeOffset: self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="Your time is too far in the future compared to mine. Closing connection.")) logger.info("%s's time is too far in the future (%s seconds). Closing connection to it.", self.destination, self.timeOffset) shared.timeOffsetWrongCount += 1 return False elif self.timeOffset < -BMProto.maxTimeOffset: self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="Your time is too far in the past compared to mine. Closing connection.")) logger.info("%s's time is too far in the past (timeOffset %s seconds). Closing connection to it.", self.destination, self.timeOffset) shared.timeOffsetWrongCount += 1 return False else: shared.timeOffsetWrongCount = 0 if not self.streams: self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="We don't have shared stream interests. Closing connection.")) logger.debug ('Closed connection to %s because there is no overlapping interest in streams.', str(self.destination)) return False if self.destination in network.connectionpool.BMConnectionPool().inboundConnections: try: if not protocol.checkSocksIP(self.destination.host): self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="Too many connections from your IP. Closing connection.")) logger.debug ('Closed connection to %s because we are already connected to that IP.', str(self.destination)) return False except: 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 state.Peer(self.destination.host, self.peerNode.port) in \ network.connectionpool.BMConnectionPool().inboundConnections or \ len(network.connectionpool.BMConnectionPool().inboundConnections) + \ len(network.connectionpool.BMConnectionPool().outboundConnections) > \ BMConfigParser().safeGetInt("bitmessagesettings", "maxtotalconnections") + \ BMConfigParser().safeGetInt("bitmessagesettings", "maxbootstrapconnections"): self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="Server full, please try again later.")) logger.debug ("Closed connection to %s due to server full or duplicate inbound/outbound.", str(self.destination)) return False if network.connectionpool.BMConnectionPool().isAlreadyConnected(self.nonce): self.append_write_buf(protocol.assembleErrorMessage(fatal=2, errorText="I'm connected to myself. Closing connection.")) logger.debug ("Closed connection to %s because I'm connected to myself.", str(self.destination)) return False return True @staticmethod def assembleAddr(peerList): if isinstance(peerList, state.Peer): peerList = (peerList) if not peerList: return b'' retval = b'' for i in range(0, len(peerList), BMProto.maxAddrCount): payload = addresses.encodeVarint(len(peerList[i:i + BMProto.maxAddrCount])) for address in peerList[i:i + BMProto.maxAddrCount]: stream, peer, timestamp = address payload += struct.pack( '>Q', timestamp) # 64-bit time payload += struct.pack('>I', stream) payload += struct.pack( '>q', 1) # service bit flags offered by this node payload += protocol.encodeHost(peer.host) payload += struct.pack('>H', peer.port) # remote port retval += protocol.CreatePacket('addr', payload) return retval @staticmethod def stopDownloadingObject(hashId, forwardAnyway=False): for connection in network.connectionpool.BMConnectionPool().inboundConnections.values() + \ network.connectionpool.BMConnectionPool().outboundConnections.values(): try: del connection.objectsNewToMe[hashId] except KeyError: pass if not forwardAnyway: try: with connection.objectsNewToThemLock: del connection.objectsNewToThem[hashId] except KeyError: pass try: del state.missingObjects[hashId] except KeyError: pass def handle_close(self): 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("%s:%i: closing", self.destination.host, self.destination.port) except AttributeError: logger.debug("Disconnected socket closing") AdvancedDispatcher.handle_close(self)