forked from LBRYCommunity/lbry-sdk
505 lines
23 KiB
Python
505 lines
23 KiB
Python
import logging
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import errno
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from binascii import hexlify
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from collections import deque
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from twisted.internet import protocol, defer
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from .error import BUILTIN_EXCEPTIONS, UnknownRemoteException, TimeoutError, TransportNotConnected
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from . import constants
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from . import encoding
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from . import msgtypes
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from . import msgformat
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log = logging.getLogger(__name__)
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class PingQueue:
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"""
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Schedules a 15 minute delayed ping after a new node sends us a query. This is so the new node gets added to the
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routing table after having been given enough time for a pinhole to expire.
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"""
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def __init__(self, node):
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self._node = node
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self._get_time = self._node.clock.seconds
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self._queue = deque()
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self._enqueued_contacts = {}
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self._semaphore = defer.DeferredSemaphore(1)
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self._ping_semaphore = defer.DeferredSemaphore(constants.alpha)
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self._process_lc = node.get_looping_call(self._semaphore.run, self._process)
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def _add_contact(self, contact, delay=None):
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if (contact.address, contact.port) in [(c.address, c.port) for c in self._enqueued_contacts]:
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return defer.succeed(None)
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delay = delay or constants.checkRefreshInterval
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self._enqueued_contacts[contact] = self._get_time() + delay
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self._queue.append(contact)
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return defer.succeed(None)
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@defer.inlineCallbacks
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def _process(self):
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if not len(self._queue):
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defer.returnValue(None)
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contact = self._queue.popleft()
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now = self._get_time()
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# if the oldest contact in the queue isn't old enough to be pinged, add it back to the queue and return
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if now < self._enqueued_contacts[contact]:
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self._queue.appendleft(contact)
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defer.returnValue(None)
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pinged = []
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checked = []
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while now > self._enqueued_contacts[contact]:
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checked.append(contact)
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if not contact.contact_is_good:
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pinged.append(contact)
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if not len(self._queue):
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break
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contact = self._queue.popleft()
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if not now > self._enqueued_contacts[contact]:
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checked.append(contact)
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@defer.inlineCallbacks
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def _ping(contact):
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try:
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yield contact.ping()
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except TimeoutError:
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pass
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except Exception as err:
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log.warning("unexpected error: %s", err)
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yield defer.DeferredList([_ping(contact) for contact in pinged])
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for contact in checked:
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if contact in self._enqueued_contacts and contact in pinged:
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del self._enqueued_contacts[contact]
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elif contact not in self._queue:
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self._queue.appendleft(contact)
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defer.returnValue(None)
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def start(self):
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return self._node.safe_start_looping_call(self._process_lc, 60)
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def stop(self):
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return self._node.safe_stop_looping_call(self._process_lc)
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def enqueue_maybe_ping(self, contact, delay=None):
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return self._semaphore.run(self._add_contact, contact, delay)
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class KademliaProtocol(protocol.DatagramProtocol):
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""" Implements all low-level network-related functions of a Kademlia node """
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msgSizeLimit = constants.udpDatagramMaxSize - 26
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def __init__(self, node):
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self._node = node
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self._translator = msgformat.DefaultFormat()
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self._sentMessages = {}
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self._partialMessages = {}
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self._partialMessagesProgress = {}
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self._listening = defer.Deferred(None)
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self._ping_queue = PingQueue(self._node)
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self._protocolVersion = constants.protocolVersion
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self.started_listening_time = 0
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def _migrate_incoming_rpc_args(self, contact, method, *args):
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if method == b'store' and contact.protocolVersion == 0:
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if isinstance(args[1], dict):
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blob_hash = args[0]
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token = args[1].pop(b'token', None)
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port = args[1].pop(b'port', -1)
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originalPublisherID = args[1].pop(b'lbryid', None)
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age = 0
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return (blob_hash, token, port, originalPublisherID, age), {}
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return args, {}
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def _migrate_outgoing_rpc_args(self, contact, method, *args):
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"""
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This will reformat protocol version 0 arguments for the store function and will add the
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protocol version keyword argument to calls to contacts who will accept it
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"""
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if contact.protocolVersion == 0:
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if method == b'store':
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blob_hash, token, port, originalPublisherID, age = args
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args = (
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blob_hash, {
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b'token': token,
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b'port': port,
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b'lbryid': originalPublisherID
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}, originalPublisherID, False
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)
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return args
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return args
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if args and isinstance(args[-1], dict):
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args[-1][b'protocolVersion'] = self._protocolVersion
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return args
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return args + ({b'protocolVersion': self._protocolVersion},)
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def sendRPC(self, contact, method, args):
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"""
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Sends an RPC to the specified contact
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@param contact: The contact (remote node) to send the RPC to
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@type contact: kademlia.contacts.Contact
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@param method: The name of remote method to invoke
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@type method: str
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@param args: A list of (non-keyword) arguments to pass to the remote
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method, in the correct order
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@type args: tuple
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@return: This immediately returns a deferred object, which will return
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the result of the RPC call, or raise the relevant exception
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if the remote node raised one. If C{rawResponse} is set to
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C{True}, however, it will always return the actual response
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message (which may be a C{ResponseMessage} or an
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C{ErrorMessage}).
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@rtype: twisted.internet.defer.Deferred
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"""
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msg = msgtypes.RequestMessage(self._node.node_id, method, self._migrate_outgoing_rpc_args(contact, method,
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*args))
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msgPrimitive = self._translator.toPrimitive(msg)
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encodedMsg = encoding.bencode(msgPrimitive)
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if args:
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log.debug("%s:%i SEND CALL %s(%s) TO %s:%i", self._node.externalIP, self._node.port, method,
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hexlify(args[0]), contact.address, contact.port)
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else:
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log.debug("%s:%i SEND CALL %s TO %s:%i", self._node.externalIP, self._node.port, method,
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contact.address, contact.port)
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df = defer.Deferred()
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def _remove_contact(failure): # remove the contact from the routing table and track the failure
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try:
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self._node.removeContact(contact)
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except (ValueError, IndexError):
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pass
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contact.update_last_failed()
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return failure
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def _update_contact(result): # refresh the contact in the routing table
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contact.update_last_replied()
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if method == b'findValue':
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if b'token' in result:
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contact.update_token(result[b'token'])
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if b'protocolVersion' not in result:
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contact.update_protocol_version(0)
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else:
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contact.update_protocol_version(result.pop(b'protocolVersion'))
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d = self._node.addContact(contact)
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d.addCallback(lambda _: result)
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return d
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df.addCallbacks(_update_contact, _remove_contact)
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# Set the RPC timeout timer
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timeoutCall, cancelTimeout = self._node.reactor_callLater(constants.rpcTimeout, self._msgTimeout, msg.id)
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# Transmit the data
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self._send(encodedMsg, msg.id, (contact.address, contact.port))
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self._sentMessages[msg.id] = (contact, df, timeoutCall, cancelTimeout, method, args)
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df.addErrback(cancelTimeout)
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return df
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def startProtocol(self):
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log.info("DHT listening on UDP %i (ext port %i)", self._node.port, self._node.externalUDPPort)
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if self._listening.called:
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self._listening = defer.Deferred()
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self._listening.callback(True)
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self.started_listening_time = self._node.clock.seconds()
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return self._ping_queue.start()
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def datagramReceived(self, datagram, address):
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""" Handles and parses incoming RPC messages (and responses)
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@note: This is automatically called by Twisted when the protocol
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receives a UDP datagram
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"""
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if chr(datagram[0]) == '\x00' and chr(datagram[25]) == '\x00':
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totalPackets = (datagram[1] << 8) | datagram[2]
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msgID = datagram[5:25]
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seqNumber = (datagram[3] << 8) | datagram[4]
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if msgID not in self._partialMessages:
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self._partialMessages[msgID] = {}
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self._partialMessages[msgID][seqNumber] = datagram[26:]
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if len(self._partialMessages[msgID]) == totalPackets:
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keys = self._partialMessages[msgID].keys()
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keys.sort()
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data = b''
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for key in keys:
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data += self._partialMessages[msgID][key]
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datagram = data
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del self._partialMessages[msgID]
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else:
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return
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try:
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msgPrimitive = encoding.bdecode(datagram)
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message = self._translator.fromPrimitive(msgPrimitive)
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except (encoding.DecodeError, ValueError) as err:
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# We received some rubbish here
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log.warning("Error decoding datagram %s from %s:%i - %s", datagram.encode('hex'),
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address[0], address[1], err)
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return
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except (IndexError, KeyError):
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log.warning("Couldn't decode dht datagram from %s", address)
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return
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if isinstance(message, msgtypes.RequestMessage):
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# This is an RPC method request
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remoteContact = self._node.contact_manager.make_contact(message.nodeID, address[0], address[1], self)
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remoteContact.update_last_requested()
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# only add a requesting contact to the routing table if it has replied to one of our requests
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if remoteContact.contact_is_good is True:
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df = self._node.addContact(remoteContact)
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else:
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df = defer.succeed(None)
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df.addCallback(lambda _: self._handleRPC(remoteContact, message.id, message.request, message.args))
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# if the contact is not known to be bad (yet) and we haven't yet queried it, send it a ping so that it
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# will be added to our routing table if successful
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if remoteContact.contact_is_good is None and remoteContact.lastReplied is None:
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df.addCallback(lambda _: self._ping_queue.enqueue_maybe_ping(remoteContact))
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elif isinstance(message, msgtypes.ErrorMessage):
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# The RPC request raised a remote exception; raise it locally
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if message.exceptionType in BUILTIN_EXCEPTIONS:
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exception_type = BUILTIN_EXCEPTIONS[message.exceptionType]
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else:
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exception_type = UnknownRemoteException
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remoteException = exception_type(message.response)
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log.error("DHT RECV REMOTE EXCEPTION FROM %s:%i: %s", address[0],
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address[1], remoteException)
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if message.id in self._sentMessages:
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# Cancel timeout timer for this RPC
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remoteContact, df, timeoutCall, timeoutCanceller, method = self._sentMessages[message.id][0:5]
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timeoutCanceller()
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del self._sentMessages[message.id]
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# reject replies coming from a different address than what we sent our request to
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if (remoteContact.address, remoteContact.port) != address:
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log.warning("Sent request to node %s at %s:%i, got reply from %s:%i",
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remoteContact.log_id(), remoteContact.address,
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remoteContact.port, address[0], address[1])
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df.errback(TimeoutError(remoteContact.id))
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return
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# this error is returned by nodes that can be contacted but have an old
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# and broken version of the ping command, if they return it the node can
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# be contacted, so we'll treat it as a successful ping
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old_ping_error = "ping() got an unexpected keyword argument '_rpcNodeContact'"
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if isinstance(remoteException, TypeError) and \
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remoteException.message == old_ping_error:
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log.debug("old pong error")
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df.callback('pong')
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else:
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df.errback(remoteException)
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elif isinstance(message, msgtypes.ResponseMessage):
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# Find the message that triggered this response
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if message.id in self._sentMessages:
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# Cancel timeout timer for this RPC
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remoteContact, df, timeoutCall, timeoutCanceller, method = self._sentMessages[message.id][0:5]
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timeoutCanceller()
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del self._sentMessages[message.id]
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log.debug("%s:%i RECV response to %s from %s:%i", self._node.externalIP, self._node.port,
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method, remoteContact.address, remoteContact.port)
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# When joining the network we made Contact objects for the seed nodes with node ids set to None
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# Thus, the sent_to_id will also be None, and the contact objects need the ids to be manually set.
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# These replies have be distinguished from those where the node id in the datagram does not match
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# the node id of the node we sent a message to (these messages are treated as an error)
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if remoteContact.id and remoteContact.id != message.nodeID: # sent_to_id will be None for bootstrap
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log.debug("mismatch: (%s) %s:%i (%s vs %s)", method, remoteContact.address, remoteContact.port,
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remoteContact.log_id(False), hexlify(message.nodeID))
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df.errback(TimeoutError(remoteContact.id))
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return
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elif not remoteContact.id:
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remoteContact.set_id(message.nodeID)
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# We got a result from the RPC
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df.callback(message.response)
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else:
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# If the original message isn't found, it must have timed out
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# TODO: we should probably do something with this...
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pass
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def _send(self, data, rpcID, address):
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""" Transmit the specified data over UDP, breaking it up into several
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packets if necessary
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If the data is spread over multiple UDP datagrams, the packets have the
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following structure::
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| | | | | |||||||||||| 0x00 |
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|Transmision|Total number|Sequence number| RPC ID |Header end|
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| type ID | of packets |of this packet | | indicator|
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| (1 byte) | (2 bytes) | (2 bytes) |(20 bytes)| (1 byte) |
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| | | | | |||||||||||| |
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@note: The header used for breaking up large data segments will
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possibly be moved out of the KademliaProtocol class in the
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future, into something similar to a message translator/encoder
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class (see C{kademlia.msgformat} and C{kademlia.encoding}).
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"""
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if len(data) > self.msgSizeLimit:
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# We have to spread the data over multiple UDP datagrams,
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# and provide sequencing information
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#
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# 1st byte is transmission type id, bytes 2 & 3 are the
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# total number of packets in this transmission, bytes 4 &
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# 5 are the sequence number for this specific packet
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totalPackets = len(data) // self.msgSizeLimit
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if len(data) % self.msgSizeLimit > 0:
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totalPackets += 1
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encTotalPackets = chr(totalPackets >> 8) + chr(totalPackets & 0xff)
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seqNumber = 0
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startPos = 0
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while seqNumber < totalPackets:
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packetData = data[startPos:startPos + self.msgSizeLimit]
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encSeqNumber = chr(seqNumber >> 8) + chr(seqNumber & 0xff)
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txData = '\x00%s%s%s\x00%s' % (encTotalPackets, encSeqNumber, rpcID, packetData)
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self._scheduleSendNext(txData, address)
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startPos += self.msgSizeLimit
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seqNumber += 1
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else:
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self._scheduleSendNext(data, address)
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def _scheduleSendNext(self, txData, address):
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"""Schedule the sending of the next UDP packet """
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delayed_call, _ = self._node.reactor_callSoon(self._write, txData, address)
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def _write(self, txData, address):
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if self.transport:
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try:
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self.transport.write(txData, address)
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except OSError as err:
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if err.errno == errno.EWOULDBLOCK:
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# i'm scared this may swallow important errors, but i get a million of these
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# on Linux and it doesnt seem to affect anything -grin
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log.warning("Can't send data to dht: EWOULDBLOCK")
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elif err.errno == errno.ENETUNREACH:
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# this should probably try to retransmit when the network connection is back
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log.error("Network is unreachable")
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else:
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log.error("DHT socket error sending %i bytes to %s:%i - %s (code %i)",
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len(txData), address[0], address[1], err.message, err.errno)
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raise err
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else:
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raise TransportNotConnected()
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def _sendResponse(self, contact, rpcID, response):
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""" Send a RPC response to the specified contact
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"""
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msg = msgtypes.ResponseMessage(rpcID, self._node.node_id, response)
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msgPrimitive = self._translator.toPrimitive(msg)
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encodedMsg = encoding.bencode(msgPrimitive)
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self._send(encodedMsg, rpcID, (contact.address, contact.port))
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def _sendError(self, contact, rpcID, exceptionType, exceptionMessage):
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""" Send an RPC error message to the specified contact
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"""
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exceptionMessage = exceptionMessage.encode()
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msg = msgtypes.ErrorMessage(rpcID, self._node.node_id, exceptionType, exceptionMessage)
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msgPrimitive = self._translator.toPrimitive(msg)
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encodedMsg = encoding.bencode(msgPrimitive)
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self._send(encodedMsg, rpcID, (contact.address, contact.port))
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def _handleRPC(self, senderContact, rpcID, method, args):
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""" Executes a local function in response to an RPC request """
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# Set up the deferred callchain
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def handleError(f):
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self._sendError(senderContact, rpcID, f.type, f.getErrorMessage())
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def handleResult(result):
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self._sendResponse(senderContact, rpcID, result)
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df = defer.Deferred()
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df.addCallback(handleResult)
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df.addErrback(handleError)
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# Execute the RPC
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func = getattr(self._node, method.decode(), None)
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if callable(func) and hasattr(func, "rpcmethod"):
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# Call the exposed Node method and return the result to the deferred callback chain
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# if args:
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# log.debug("%s:%i RECV CALL %s(%s) %s:%i", self._node.externalIP, self._node.port, method,
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# args[0].encode('hex'), senderContact.address, senderContact.port)
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# else:
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log.debug("%s:%i RECV CALL %s %s:%i", self._node.externalIP, self._node.port, method,
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senderContact.address, senderContact.port)
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if args and isinstance(args[-1], dict) and b'protocolVersion' in args[-1]: # args don't need reformatting
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senderContact.update_protocol_version(int(args[-1].pop(b'protocolVersion')))
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a, kw = tuple(args[:-1]), args[-1]
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else:
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senderContact.update_protocol_version(0)
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a, kw = self._migrate_incoming_rpc_args(senderContact, method, *args)
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try:
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if method != b'ping':
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result = func(senderContact, *a)
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else:
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result = func()
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except Exception as e:
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log.exception("error handling request for %s:%i %s", senderContact.address, senderContact.port, method)
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df.errback(e)
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else:
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df.callback(result)
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else:
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# No such exposed method
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df.errback(AttributeError('Invalid method: %s' % method))
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return df
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def _msgTimeout(self, messageID):
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""" Called when an RPC request message times out """
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# Find the message that timed out
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if messageID not in self._sentMessages:
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# This should never be reached
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log.error("deferred timed out, but is not present in sent messages list!")
|
|
return
|
|
remoteContact, df, timeout_call, timeout_canceller, method, args = self._sentMessages[messageID]
|
|
if messageID in self._partialMessages:
|
|
# We are still receiving this message
|
|
self._msgTimeoutInProgress(messageID, timeout_canceller, remoteContact, df, method, args)
|
|
return
|
|
del self._sentMessages[messageID]
|
|
# The message's destination node is now considered to be dead;
|
|
# raise an (asynchronous) TimeoutError exception and update the host node
|
|
df.errback(TimeoutError(remoteContact.id))
|
|
|
|
def _msgTimeoutInProgress(self, messageID, timeoutCanceller, remoteContact, df, method, args):
|
|
# See if any progress has been made; if not, kill the message
|
|
if self._hasProgressBeenMade(messageID):
|
|
# Reset the RPC timeout timer
|
|
timeoutCanceller()
|
|
timeoutCall, cancelTimeout = self._node.reactor_callLater(constants.rpcTimeout, self._msgTimeout, messageID)
|
|
self._sentMessages[messageID] = (remoteContact, df, timeoutCall, cancelTimeout, method, args)
|
|
else:
|
|
# No progress has been made
|
|
if messageID in self._partialMessagesProgress:
|
|
del self._partialMessagesProgress[messageID]
|
|
if messageID in self._partialMessages:
|
|
del self._partialMessages[messageID]
|
|
df.errback(TimeoutError(remoteContact.id))
|
|
|
|
def _hasProgressBeenMade(self, messageID):
|
|
return (
|
|
messageID in self._partialMessagesProgress and
|
|
(
|
|
len(self._partialMessagesProgress[messageID]) !=
|
|
len(self._partialMessages[messageID])
|
|
)
|
|
)
|
|
|
|
def stopProtocol(self):
|
|
""" Called when the transport is disconnected.
|
|
|
|
Will only be called once, after all ports are disconnected.
|
|
"""
|
|
log.info('Stopping DHT')
|
|
self._ping_queue.stop()
|
|
self._node.call_later_manager.stop()
|
|
log.info('DHT stopped')
|