p2pool/p2p.py

   1 from __future__ import division
   2
   3 import math
   4 import random
   5 import time
   6
   7 from twisted.internet import defer, protocol, reactor
   8 from twisted.python import failure, log
   9
  10 import p2pool
  11 from p2pool import data as p2pool_data
  12 from p2pool.bitcoin import data as bitcoin_data
  13 from p2pool.util import deferral, p2protocol, pack, variable
  14
  15 class PeerMisbehavingError(Exception):
  16     pass
  17
  18
  19 def fragment(f, **kwargs):
  20     try:
  21         return f(**kwargs)
  22     except p2protocol.TooLong:
  23         att(f, **dict((k, v[:len(v)//2]) for k, v in kwargs.iteritems()))
  24         return att(f, **dict((k, v[len(v)//2:]) for k, v in kwargs.iteritems()))
  25
  26 class Protocol(p2protocol.Protocol):
  27     max_remembered_txs_size = 2500000
  28
  29     def __init__(self, node, incoming):
  30         p2protocol.Protocol.__init__(self, node.net.PREFIX, 1000000, node.traffic_happened)
  31         self.node = node
  32         self.incoming = incoming
  33
  34         self.other_version = None
  35         self.connected2 = False
  36
  37     def connectionMade(self):
  38         p2protocol.Protocol.connectionMade(self)
  39
  40         self.factory.proto_made_connection(self)
  41
  42         self.connection_lost_event = variable.Event()
  43
  44         self.addr = self.transport.getPeer().host, self.transport.getPeer().port
  45
  46         self.send_version(
  47             version=4,
  48             services=0,
  49             addr_to=dict(
  50                 services=0,
  51                 address=self.transport.getPeer().host,
  52                 port=self.transport.getPeer().port,
  53             ),
  54             addr_from=dict(
  55                 services=0,
  56                 address=self.transport.getHost().host,
  57                 port=self.transport.getHost().port,
  58             ),
  59             nonce=self.node.nonce,
  60             sub_version=p2pool.__version__,
  61             mode=1,
  62             best_share_hash=self.node.best_share_hash_func(),
  63         )
  64
  65         self.timeout_delayed = reactor.callLater(10, self._connect_timeout)
  66
  67         self.get_shares = deferral.GenericDeferrer(
  68             max_id=2**256,
  69             func=lambda id, hashes, parents, stops: self.send_sharereq(id=id, hashes=hashes, parents=parents, stops=stops),
  70             timeout=15,
  71             on_timeout=self.transport.loseConnection,
  72         )
  73
  74         self.remote_tx_hashes = set() # view of peer's known_txs # not actually initially empty, but sending txs instead of tx hashes won't hurt
  75         self.remote_remembered_txs_size = 0
  76
  77         self.remembered_txs = {} # view of peer's mining_txs
  78         self.remembered_txs_size = 0
  79
  80     def _connect_timeout(self):
  81         self.timeout_delayed = None
  82         print 'Handshake timed out, disconnecting from %s:%i' % self.addr
  83         self.transport.loseConnection()
  84
  85     def packetReceived(self, command, payload2):
  86         try:
  87             if command != 'version' and not self.connected2:
  88                 raise PeerMisbehavingError('first message was not version message')
  89             p2protocol.Protocol.packetReceived(self, command, payload2)
  90         except PeerMisbehavingError, e:
  91             print 'Peer %s:%i misbehaving, will drop and ban. Reason:' % self.addr, e.message
  92             self.badPeerHappened()
  93
  94     def badPeerHappened(self):
  95         if p2pool.DEBUG:
  96             print "Bad peer banned:", self.addr
  97         self.transport.loseConnection()
  98         self.node.bans[self.transport.getPeer().host] = time.time() + 60*60
  99
 100     def _timeout(self):
 101         self.timeout_delayed = None
 102         print 'Connection timed out, disconnecting from %s:%i' % self.addr
 103         self.transport.loseConnection()
 104
 105     message_version = pack.ComposedType([
 106         ('version', pack.IntType(32)),
 107         ('services', pack.IntType(64)),
 108         ('addr_to', bitcoin_data.address_type),
 109         ('addr_from', bitcoin_data.address_type),
 110         ('nonce', pack.IntType(64)),
 111         ('sub_version', pack.VarStrType()),
 112         ('mode', pack.IntType(32)), # always 1 for legacy compatibility
 113         ('best_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
 114     ])
 115     def handle_version(self, version, services, addr_to, addr_from, nonce, sub_version, mode, best_share_hash):
 116         if self.other_version is not None:
 117             raise PeerMisbehavingError('more than one version message')
 118         if version < 4:
 119             raise PeerMisbehavingError('peer too old')
 120
 121         self.other_version = version
 122         self.other_sub_version = sub_version[:512]
 123         self.other_services = services
 124
 125         if nonce == self.node.nonce:
 126             raise PeerMisbehavingError('was connected to self')
 127         if nonce in self.node.peers:
 128             if p2pool.DEBUG:
 129                 print 'Detected duplicate connection, disconnecting from %s:%i' % self.addr
 130             self.transport.loseConnection()
 131             return
 132
 133         self.nonce = nonce
 134         self.connected2 = True
 135
 136         self.timeout_delayed.cancel()
 137         self.timeout_delayed = reactor.callLater(100, self._timeout)
 138
 139         old_dataReceived = self.dataReceived
 140         def new_dataReceived(data):
 141             if self.timeout_delayed is not None:
 142                 self.timeout_delayed.reset(100)
 143             old_dataReceived(data)
 144         self.dataReceived = new_dataReceived
 145
 146         self.factory.proto_connected(self)
 147
 148         self._stop_thread = deferral.run_repeatedly(lambda: [
 149             self.send_ping(),
 150         random.expovariate(1/100)][-1])
 151
 152         self._stop_thread2 = deferral.run_repeatedly(lambda: [
 153             self.send_addrme(port=self.node.port),
 154         random.expovariate(1/(100*len(self.node.peers) + 1))][-1])
 155
 156         if best_share_hash is not None:
 157             self.node.handle_share_hashes([best_share_hash], self)
 158
 159         def update_remote_view_of_my_known_txs(before, after):
 160             added = set(after) - set(before)
 161             removed = set(before) - set(after)
 162             if added:
 163                 self.send_have_tx(tx_hashes=list(added))
 164             if removed:
 165                 self.send_losing_tx(tx_hashes=list(removed))
 166                 # XXX cache locally
 167         watch_id = self.node.known_txs_var.transitioned.watch(update_remote_view_of_my_known_txs)
 168         self.connection_lost_event.watch(lambda: self.node.known_txs_var.transitioned.unwatch(watch_id))
 169
 170         self.send_have_tx(tx_hashes=self.node.known_txs_var.value.keys())
 171
 172         def update_remote_view_of_my_mining_txs(before, after):
 173             added = set(after) - set(before)
 174             removed = set(before) - set(after)
 175             if added:
 176                 self.remote_remembered_txs_size += sum(len(bitcoin_data.tx_type.pack(after[x])) for x in added)
 177                 assert self.remote_remembered_txs_size <= self.max_remembered_txs_size
 178                 fragment(self.send_remember_tx, tx_hashes=[x for x in added if x in self.remote_tx_hashes], txs=[after[x] for x in added if x not in self.remote_tx_hashes])
 179             if removed:
 180                 self.send_forget_tx(tx_hashes=removed)
 181                 self.remote_remembered_txs_size -= sum(len(bitcoin_data.tx_type.pack(before[x])) for x in removed)
 182         watch_id2 = self.node.mining_txs_var.transitioned.watch(update_remote_view_of_my_mining_txs)
 183         self.connection_lost_event.watch(lambda: self.node.mining_txs_var.transitioned.unwatch(watch_id2))
 184
 185         self.remote_remembered_txs_size += sum(len(bitcoin_data.tx_type.pack(x)) for x in self.node.mining_txs_var.value.values())
 186         assert self.remote_remembered_txs_size <= self.max_remembered_txs_size
 187         fragment(self.send_remember_tx, tx_hashes=[], txs=self.node.mining_txs_var.value.values())
 188
 189     message_ping = pack.ComposedType([])
 190     def handle_ping(self):
 191         pass
 192
 193     message_addrme = pack.ComposedType([
 194         ('port', pack.IntType(16)),
 195     ])
 196     def handle_addrme(self, port):
 197         host = self.transport.getPeer().host
 198         #print 'addrme from', host, port
 199         if host == '127.0.0.1':
 200             if random.random() < .8 and self.node.peers:
 201                 random.choice(self.node.peers.values()).send_addrme(port=port) # services...
 202         else:
 203             self.node.got_addr((self.transport.getPeer().host, port), self.other_services, int(time.time()))
 204             if random.random() < .8 and self.node.peers:
 205                 random.choice(self.node.peers.values()).send_addrs(addrs=[
 206                     dict(
 207                         address=dict(
 208                             services=self.other_services,
 209                             address=host,
 210                             port=port,
 211                         ),
 212                         timestamp=int(time.time()),
 213                     ),
 214                 ])
 215
 216     message_addrs = pack.ComposedType([
 217         ('addrs', pack.ListType(pack.ComposedType([
 218             ('timestamp', pack.IntType(64)),
 219             ('address', bitcoin_data.address_type),
 220         ]))),
 221     ])
 222     def handle_addrs(self, addrs):
 223         for addr_record in addrs:
 224             self.node.got_addr((addr_record['address']['address'], addr_record['address']['port']), addr_record['address']['services'], min(int(time.time()), addr_record['timestamp']))
 225             if random.random() < .8 and self.node.peers:
 226                 random.choice(self.node.peers.values()).send_addrs(addrs=[addr_record])
 227
 228     message_getaddrs = pack.ComposedType([
 229         ('count', pack.IntType(32)),
 230     ])
 231     def handle_getaddrs(self, count):
 232         if count > 100:
 233             count = 100
 234         self.send_addrs(addrs=[
 235             dict(
 236                 timestamp=int(self.node.addr_store[host, port][2]),
 237                 address=dict(
 238                     services=self.node.addr_store[host, port][0],
 239                     address=host,
 240                     port=port,
 241                 ),
 242             ) for host, port in
 243             self.node.get_good_peers(count)
 244         ])
 245
 246     message_shares = pack.ComposedType([
 247         ('shares', pack.ListType(p2pool_data.share_type)),
 248     ])
 249     def handle_shares(self, shares):
 250         self.node.handle_shares([p2pool_data.load_share(share, self.node.net, self) for share in shares if share['type'] not in [6, 7]], self)
 251
 252     def sendShares(self, shares, tracker, known_txs, include_txs_with=[]):
 253         if not shares:
 254             return defer.succeed(None)
 255
 256         tx_hashes = set()
 257         for share in shares:
 258             if share.hash in include_txs_with:
 259                 tx_hashes.update(share.get_other_tx_hashes(tracker))
 260
 261         hashes_to_send = [x for x in tx_hashes if x not in self.node.mining_txs_var.value and x in known_txs]
 262
 263         new_remote_remembered_txs_size = self.remote_remembered_txs_size + sum(len(bitcoin_data.tx_type.pack(known_txs[x])) for x in hashes_to_send)
 264         if new_remote_remembered_txs_size > self.max_remembered_txs_size:
 265             raise ValueError('shares have too many txs')
 266         self.remote_remembered_txs_size = new_remote_remembered_txs_size
 267
 268         fragment(self.send_remember_tx, tx_hashes=[x for x in hashes_to_send if x in self.remote_tx_hashes], txs=[known_txs[x] for x in hashes_to_send if x not in self.remote_tx_hashes])
 269         fragment(self.send_shares, shares=[share.as_share() for share in shares])
 270         res = self.send_forget_tx(tx_hashes=hashes_to_send)
 271
 272         self.remote_remembered_txs_size -= sum(len(bitcoin_data.tx_type.pack(known_txs[x])) for x in hashes_to_send)
 273
 274         return res
 275
 276
 277     message_sharereq = pack.ComposedType([
 278         ('id', pack.IntType(256)),
 279         ('hashes', pack.ListType(pack.IntType(256))),
 280         ('parents', pack.VarIntType()),
 281         ('stops', pack.ListType(pack.IntType(256))),
 282     ])
 283     def handle_sharereq(self, id, hashes, parents, stops):
 284         shares = self.node.handle_get_shares(hashes, parents, stops, self)
 285         try:
 286             self.send_sharereply(id=id, result='good', shares=[share.as_share() for share in shares])
 287         except p2protocol.TooLong:
 288             self.send_sharereply(id=id, result='too long', shares=[])
 289
 290     message_sharereply = pack.ComposedType([
 291         ('id', pack.IntType(256)),
 292         ('result', pack.EnumType(pack.VarIntType(), {0: 'good', 1: 'too long', 2: 'unk2', 3: 'unk3', 4: 'unk4', 5: 'unk5', 6: 'unk6'})),
 293         ('shares', pack.ListType(p2pool_data.share_type)),
 294     ])
 295     def handle_sharereply(self, id, result, shares):
 296         if result == 'good':
 297             res = [p2pool_data.load_share(share, self.node.net, self) for share in shares if share['type'] not in [6, 7]]
 298         else:
 299             res = failure.Failure("sharereply result: " + result)
 300         self.get_shares.got_response(id, res)
 301
 302
 303     message_bestblock = pack.ComposedType([
 304         ('header', bitcoin_data.block_header_type),
 305     ])
 306     def handle_bestblock(self, header):
 307         self.node.handle_bestblock(header, self)
 308
 309
 310     message_have_tx = pack.ComposedType([
 311         ('tx_hashes', pack.ListType(pack.IntType(256))),
 312     ])
 313     def handle_have_tx(self, tx_hashes):
 314         self.remote_tx_hashes.update(tx_hashes)
 315     message_losing_tx = pack.ComposedType([
 316         ('tx_hashes', pack.ListType(pack.IntType(256))),
 317     ])
 318     def handle_losing_tx(self, tx_hashes):
 319         self.remote_tx_hashes.difference_update(tx_hashes)
 320
 321
 322     message_remember_tx = pack.ComposedType([
 323         ('tx_hashes', pack.ListType(pack.IntType(256))),
 324         ('txs', pack.ListType(bitcoin_data.tx_type)),
 325     ])
 326     def handle_remember_tx(self, tx_hashes, txs):
 327         for tx_hash in tx_hashes:
 328             if tx_hash not in self.remembered_txs:
 329                 self.remembered_txs[tx_hash] = self.node.known_txs_var.value[tx_hash]
 330                 self.remembered_txs_size += len(bitcoin_data.tx_type.pack(self.node.known_txs_var.value[tx_hash]))
 331         new_known_txs = dict(self.node.known_txs_var.value)
 332         for tx in txs:
 333             tx_hash = bitcoin_data.hash256(bitcoin_data.tx_type.pack(tx))
 334             if tx_hash not in self.remembered_txs:
 335                 self.remembered_txs[tx_hash] = tx
 336                 self.remembered_txs_size += len(bitcoin_data.tx_type.pack(tx))
 337             new_known_txs[tx_hash] = tx
 338         self.node.known_txs_var.set(new_known_txs)
 339         if self.remembered_txs_size >= self.max_remembered_txs_size:
 340             raise PeerMisbehavingError('too much transaction data stored')
 341     message_forget_tx = pack.ComposedType([
 342         ('tx_hashes', pack.ListType(pack.IntType(256))),
 343     ])
 344     def handle_forget_tx(self, tx_hashes):
 345         for tx_hash in tx_hashes:
 346             self.remembered_txs_size -= len(bitcoin_data.tx_type.pack(self.remembered_txs[tx_hash]))
 347             assert self.remembered_txs_size >= 0
 348             del self.remembered_txs[tx_hash]
 349
 350
 351     def connectionLost(self, reason):
 352         self.connection_lost_event.happened()
 353         if self.timeout_delayed is not None:
 354             self.timeout_delayed.cancel()
 355         if self.connected2:
 356             self.factory.proto_disconnected(self, reason)
 357             self._stop_thread()
 358             self._stop_thread2()
 359             self.connected2 = False
 360         self.factory.proto_lost_connection(self, reason)
 361         if p2pool.DEBUG:
 362             print "Peer connection lost:", self.addr, reason
 363         self.get_shares.respond_all(reason)
 364
 365     @defer.inlineCallbacks
 366     def do_ping(self):
 367         start = reactor.seconds()
 368         yield self.get_shares(hashes=[0], parents=0, stops=[])
 369         end = reactor.seconds()
 370         defer.returnValue(end - start)
 371
 372 class ServerFactory(protocol.ServerFactory):
 373     def __init__(self, node, max_conns):
 374         self.node = node
 375         self.max_conns = max_conns
 376
 377         self.conns = {}
 378         self.running = False
 379
 380     def buildProtocol(self, addr):
 381         if sum(self.conns.itervalues()) >= self.max_conns or self.conns.get(self._host_to_ident(addr.host), 0) >= 3:
 382             return None
 383         if addr.host in self.node.bans and self.node.bans[addr.host] > time.time():
 384             return None
 385         p = Protocol(self.node, True)
 386         p.factory = self
 387         if p2pool.DEBUG:
 388             print "Got peer connection from:", addr
 389         return p
 390
 391     def _host_to_ident(self, host):
 392         a, b, c, d = host.split('.')
 393         return a, b
 394
 395     def proto_made_connection(self, proto):
 396         ident = self._host_to_ident(proto.transport.getPeer().host)
 397         self.conns[ident] = self.conns.get(ident, 0) + 1
 398     def proto_lost_connection(self, proto, reason):
 399         ident = self._host_to_ident(proto.transport.getPeer().host)
 400         self.conns[ident] -= 1
 401         if not self.conns[ident]:
 402             del self.conns[ident]
 403
 404     def proto_connected(self, proto):
 405         self.node.got_conn(proto)
 406     def proto_disconnected(self, proto, reason):
 407         self.node.lost_conn(proto, reason)
 408
 409     def start(self):
 410         assert not self.running
 411         self.running = True
 412
 413         def attempt_listen():
 414             if self.running:
 415                 self.listen_port = reactor.listenTCP(self.node.port, self)
 416         deferral.retry('Error binding to P2P port:', traceback=False)(attempt_listen)()
 417
 418     def stop(self):
 419         assert self.running
 420         self.running = False
 421
 422         return self.listen_port.stopListening()
 423
 424 class ClientFactory(protocol.ClientFactory):
 425     def __init__(self, node, desired_conns, max_attempts):
 426         self.node = node
 427         self.desired_conns = desired_conns
 428         self.max_attempts = max_attempts
 429
 430         self.attempts = set()
 431         self.conns = set()
 432         self.running = False
 433
 434     def _host_to_ident(self, host):
 435         a, b, c, d = host.split('.')
 436         return a, b
 437
 438     def buildProtocol(self, addr):
 439         p = Protocol(self.node, False)
 440         p.factory = self
 441         return p
 442
 443     def startedConnecting(self, connector):
 444         ident = self._host_to_ident(connector.getDestination().host)
 445         if ident in self.attempts:
 446             raise AssertionError('already have attempt')
 447         self.attempts.add(ident)
 448
 449     def clientConnectionFailed(self, connector, reason):
 450         self.attempts.remove(self._host_to_ident(connector.getDestination().host))
 451
 452     def clientConnectionLost(self, connector, reason):
 453         self.attempts.remove(self._host_to_ident(connector.getDestination().host))
 454
 455     def proto_made_connection(self, proto):
 456         pass
 457     def proto_lost_connection(self, proto, reason):
 458         pass
 459
 460     def proto_connected(self, proto):
 461         self.conns.add(proto)
 462         self.node.got_conn(proto)
 463     def proto_disconnected(self, proto, reason):
 464         self.conns.remove(proto)
 465         self.node.lost_conn(proto, reason)
 466
 467     def start(self):
 468         assert not self.running
 469         self.running = True
 470         self._stop_thinking = deferral.run_repeatedly(self._think)
 471     def stop(self):
 472         assert self.running
 473         self.running = False
 474         self._stop_thinking()
 475
 476     def _think(self):
 477         try:
 478             if len(self.conns) < self.desired_conns and len(self.attempts) < self.max_attempts and self.node.addr_store:
 479                 (host, port), = self.node.get_good_peers(1)
 480
 481                 if self._host_to_ident(host) in self.attempts:
 482                     pass
 483                 elif host in self.node.bans and self.node.bans[host] > time.time():
 484                     pass
 485                 else:
 486                     #print 'Trying to connect to', host, port
 487                     reactor.connectTCP(host, port, self, timeout=5)
 488         except:
 489             log.err()
 490
 491         return random.expovariate(1/1)
 492
 493 class SingleClientFactory(protocol.ReconnectingClientFactory):
 494     def __init__(self, node):
 495         self.node = node
 496
 497     def buildProtocol(self, addr):
 498         p = Protocol(self.node, incoming=False)
 499         p.factory = self
 500         return p
 501
 502     def proto_made_connection(self, proto):
 503         pass
 504     def proto_lost_connection(self, proto, reason):
 505         pass
 506
 507     def proto_connected(self, proto):
 508         self.resetDelay()
 509         self.node.got_conn(proto)
 510     def proto_disconnected(self, proto, reason):
 511         self.node.lost_conn(proto, reason)
 512
 513 class Node(object):
 514     def __init__(self, best_share_hash_func, port, net, addr_store={}, connect_addrs=set(), desired_outgoing_conns=10, max_outgoing_attempts=30, max_incoming_conns=50, preferred_storage=1000, traffic_happened=variable.Event(), known_txs_var=variable.Variable({}), mining_txs_var=variable.Variable({})):
 515         self.best_share_hash_func = best_share_hash_func
 516         self.port = port
 517         self.net = net
 518         self.addr_store = dict(addr_store)
 519         self.connect_addrs = connect_addrs
 520         self.preferred_storage = preferred_storage
 521         self.traffic_happened = traffic_happened
 522         self.known_txs_var = known_txs_var
 523         self.mining_txs_var = mining_txs_var
 524
 525         self.nonce = random.randrange(2**64)
 526         self.peers = {}
 527         self.bans = {} # address -> end_time
 528         self.clientfactory = ClientFactory(self, desired_outgoing_conns, max_outgoing_attempts)
 529         self.serverfactory = ServerFactory(self, max_incoming_conns)
 530         self.running = False
 531
 532     def start(self):
 533         if self.running:
 534             raise ValueError('already running')
 535
 536         self.clientfactory.start()
 537         self.serverfactory.start()
 538         self.singleclientconnectors = [reactor.connectTCP(addr, port, SingleClientFactory(self)) for addr, port in self.connect_addrs]
 539
 540         self.running = True
 541
 542         self._stop_thinking = deferral.run_repeatedly(self._think)
 543
 544     def _think(self):
 545         try:
 546             if len(self.addr_store) < self.preferred_storage and self.peers:
 547                 random.choice(self.peers.values()).send_getaddrs(count=8)
 548         except:
 549             log.err()
 550
 551         return random.expovariate(1/20)
 552
 553     @defer.inlineCallbacks
 554     def stop(self):
 555         if not self.running:
 556             raise ValueError('already stopped')
 557
 558         self.running = False
 559
 560         self._stop_thinking()
 561         yield self.clientfactory.stop()
 562         yield self.serverfactory.stop()
 563         for singleclientconnector in self.singleclientconnectors:
 564             yield singleclientconnector.factory.stopTrying()
 565             yield singleclientconnector.disconnect()
 566         del self.singleclientconnectors
 567
 568     def got_conn(self, conn):
 569         if conn.nonce in self.peers:
 570             raise ValueError('already have peer')
 571         self.peers[conn.nonce] = conn
 572
 573         print '%s connection to peer %s:%i established. p2pool version: %i %r' % ('Incoming' if conn.incoming else 'Outgoing', conn.addr[0], conn.addr[1], conn.other_version, conn.other_sub_version)
 574
 575     def lost_conn(self, conn, reason):
 576         if conn.nonce not in self.peers:
 577             raise ValueError('''don't have peer''')
 578         if conn is not self.peers[conn.nonce]:
 579             raise ValueError('wrong conn')
 580         del self.peers[conn.nonce]
 581
 582         print 'Lost peer %s:%i - %s' % (conn.addr[0], conn.addr[1], reason.getErrorMessage())
 583
 584
 585     def got_addr(self, (host, port), services, timestamp):
 586         if (host, port) in self.addr_store:
 587             old_services, old_first_seen, old_last_seen = self.addr_store[host, port]
 588             self.addr_store[host, port] = services, old_first_seen, max(old_last_seen, timestamp)
 589         else:
 590             self.addr_store[host, port] = services, timestamp, timestamp
 591
 592     def handle_shares(self, shares, peer):
 593         print 'handle_shares', (shares, peer)
 594
 595     def handle_share_hashes(self, hashes, peer):
 596         print 'handle_share_hashes', (hashes, peer)
 597
 598     def handle_get_shares(self, hashes, parents, stops, peer):
 599         print 'handle_get_shares', (hashes, parents, stops, peer)
 600
 601     def handle_bestblock(self, header, peer):
 602         print 'handle_bestblock', header
 603
 604     def get_good_peers(self, max_count):
 605         t = time.time()
 606         return [x[0] for x in sorted(self.addr_store.iteritems(), key=lambda (k, (services, first_seen, last_seen)):
 607             -math.log(max(3600, last_seen - first_seen))/math.log(max(3600, t - last_seen))*random.expovariate(1)
 608         )][:max_count]