p2pool/data.py

   1 from __future__ import division
   2
   3 import itertools
   4 import random
   5 import time
   6 import os
   7
   8 from twisted.python import log
   9
  10 import p2pool
  11 from p2pool import skiplists
  12 from p2pool.bitcoin import data as bitcoin_data, script, networks
  13 from p2pool.util import memoize, expiring_dict, math
  14
  15
  16 merkle_branch_type = bitcoin_data.ListType(bitcoin_data.ComposedType([
  17     ('side', bitcoin_data.StructType('<B')), # enum?
  18     ('hash', bitcoin_data.HashType()),
  19 ]))
  20
  21
  22 share_data_type = bitcoin_data.ComposedType([
  23     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  24     ('target', bitcoin_data.FloatingIntegerType()),
  25     ('nonce', bitcoin_data.VarStrType()),
  26 ])
  27
  28
  29 coinbase_type = bitcoin_data.ComposedType([
  30     ('identifier', bitcoin_data.FixedStrType(8)),
  31     ('share_data', share_data_type),
  32 ])
  33
  34 share_info_type = bitcoin_data.ComposedType([
  35     ('share_data', share_data_type),
  36     ('new_script', bitcoin_data.VarStrType()),
  37     ('subsidy', bitcoin_data.StructType('<Q')),
  38 ])
  39
  40
  41 share1a_type = bitcoin_data.ComposedType([
  42     ('header', bitcoin_data.block_header_type),
  43     ('share_info', share_info_type),
  44     ('merkle_branch', merkle_branch_type),
  45 ])
  46
  47 share1b_type = bitcoin_data.ComposedType([
  48     ('header', bitcoin_data.block_header_type),
  49     ('share_info', share_info_type),
  50     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  51 ])
  52
  53 new_share_data_type = bitcoin_data.ComposedType([
  54     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  55     ('coinbase', bitcoin_data.VarStrType()),
  56     ('nonce', bitcoin_data.VarStrType()),
  57     ('new_script', bitcoin_data.VarStrType()),
  58     ('subsidy', bitcoin_data.StructType('<Q')),
  59     ('donation', bitcoin_data.StructType('<H')),
  60     ('timestamp', bitcoin_data.StructType('<I')),
  61 ])
  62
  63 new_share_info_type = bitcoin_data.ComposedType([
  64     ('new_share_data', new_share_data_type),
  65     ('target', bitcoin_data.FloatingIntegerType()),
  66 ])
  67
  68 new_share1a_type = bitcoin_data.ComposedType([
  69     ('header', bitcoin_data.block_header_type),
  70     ('share_info', new_share_info_type),
  71     ('merkle_branch', bitcoin_data.merkle_branch_type),
  72 ])
  73
  74 new_share1b_type = bitcoin_data.ComposedType([
  75     ('header', bitcoin_data.block_header_type),
  76     ('share_info', new_share_info_type),
  77     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  78 ])
  79
  80 def calculate_merkle_branch(txs, index):
  81     hash_list = [(bitcoin_data.tx_type.hash256(tx), i == index, []) for i, tx in enumerate(txs)]
  82
  83     while len(hash_list) > 1:
  84         hash_list = [
  85             (
  86                 bitcoin_data.merkle_record_type.hash256(dict(left=left, right=right)),
  87                 left_f or right_f,
  88                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
  89             )
  90             for (left, left_f, left_l), (right, right_f, right_l) in
  91                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
  92         ]
  93
  94     assert hash_list[0][1]
  95     assert check_merkle_branch(txs[index], hash_list[0][2]) == hash_list[0][0]
  96
  97     return hash_list[0][2]
  98
  99 def check_merkle_branch(tx, branch):
 100     hash_ = bitcoin_data.tx_type.hash256(tx)
 101     for step in branch:
 102         if not step['side']:
 103             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=step['hash'], right=hash_))
 104         else:
 105             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=hash_, right=step['hash']))
 106     return hash_
 107
 108 def share_info_to_gentx(share_info, block_target, tracker, net):
 109     return generate_transaction(
 110         tracker=tracker,
 111         previous_share_hash=share_info['share_data']['previous_share_hash'],
 112         new_script=share_info['new_script'],
 113         subsidy=share_info['subsidy'],
 114         nonce=share_info['share_data']['nonce'],
 115         block_target=block_target,
 116         net=net,
 117     )[1]
 118
 119 class Share(object):
 120     donation = 0
 121
 122     @classmethod
 123     def from_share1a(cls, share1a, net):
 124         return cls(net, **share1a)
 125
 126     @classmethod
 127     def from_share1b(cls, share1b, net):
 128         return cls(net, **share1b)
 129
 130     __slots__ = 'header previous_block share_info merkle_branch other_txs timestamp share_data new_script subsidy previous_hash previous_share_hash target nonce pow_hash header_hash hash time_seen shared stored peer'.split(' ')
 131
 132     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 133         if merkle_branch is None and other_txs is None:
 134             raise ValueError('need either merkle_branch or other_txs')
 135         if other_txs is not None:
 136             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 137             if merkle_branch is not None:
 138                 if merke_branch != new_merkle_branch:
 139                     raise ValueError('invalid merkle_branch and other_txs')
 140             merkle_branch = new_merkle_branch
 141
 142         if len(merkle_branch) > 16:
 143             raise ValueError('merkle_branch too long!')
 144
 145         self.header = header
 146         self.previous_block = header['previous_block']
 147         self.share_info = share_info
 148         self.merkle_branch = merkle_branch
 149         self.other_txs = other_txs
 150
 151         self.timestamp = self.header['timestamp']
 152
 153         self.share_data = self.share_info['share_data']
 154         self.new_script = self.share_info['new_script']
 155         self.subsidy = self.share_info['subsidy']
 156
 157         if len(self.new_script) > 100:
 158             raise ValueError('new_script too long!')
 159
 160         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 161         self.target = self.share_data['target']
 162         self.nonce = self.share_data['nonce']
 163
 164         if len(self.nonce) > 100:
 165             raise ValueError('nonce too long!')
 166
 167         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 168         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 169
 170         if net.BITCOIN_POW_FUNC is bitcoin_data.block_header_type.scrypt:
 171             # compatibility hack
 172             self.hash = share1a_type.scrypt(self.as_share1a())
 173         else:
 174             self.hash = share1a_type.hash256(self.as_share1a())
 175
 176         if self.pow_hash > self.target:
 177             print 'hash %x' % self.pow_hash
 178             print 'targ %x' % self.target
 179             raise ValueError('not enough work!')
 180
 181         if script.get_sigop_count(self.new_script) > 1:
 182             raise ValueError('too many sigops!')
 183
 184         # XXX eww
 185         self.time_seen = time.time()
 186         self.shared = False
 187         self.stored = False
 188         self.peer = None
 189
 190     def as_block(self, tracker, net):
 191         if self.other_txs is None:
 192             raise ValueError('share does not contain all txs')
 193
 194         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 195
 196         return dict(header=self.header, txs=[gentx] + self.other_txs)
 197
 198     def as_share1a(self):
 199         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 200
 201     def as_share1b(self):
 202         if self.other_txs is None:
 203             raise ValueError('share does not contain all txs')
 204
 205         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 206
 207     def check(self, tracker, now, net):
 208         import time
 209         if self.previous_share_hash is not None:
 210             if self.header['timestamp'] <= math.median((s.timestamp for s in itertools.islice(tracker.get_chain_to_root(self.previous_share_hash), 11)), use_float=False):
 211                 raise ValueError('share from too far in the past!')
 212
 213         if self.header['timestamp'] > now + 2*60*60:
 214             raise ValueError('share from too far in the future!')
 215
 216         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 217
 218         if len(gentx['tx_ins'][0]['script']) > 100:
 219             raise ValueError('coinbase too large! %i bytes' % (len(gentx['tx_ins'][0]['script']),))
 220
 221         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
 222             raise ValueError('''gentx doesn't match header via merkle_branch''')
 223
 224         if self.other_txs is not None:
 225             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 226                 raise ValueError('''gentx doesn't match header via other_txs''')
 227
 228             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 229                 raise ValueError('block size too large')
 230
 231     def flag_shared(self):
 232         self.shared = True
 233
 234     def __repr__(self):
 235         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 236
 237 class NewShare(Share):
 238     def __init__(self, net, header, new_share_info, merkle_branch=None, other_txs=None):
 239         if merkle_branch is None and other_txs is None:
 240             raise ValueError('need either merkle_branch or other_txs')
 241         if other_txs is not None:
 242             new_merkle_branch = bitcoin_data.calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 243             if merkle_branch is not None:
 244                 if merke_branch != new_merkle_branch:
 245                     raise ValueError('invalid merkle_branch and other_txs')
 246             merkle_branch = new_merkle_branch
 247
 248         if len(merkle_branch) > 16:
 249             raise ValueError('merkle_branch too long!')
 250
 251         self.header = header
 252         self.previous_block = header['previous_block']
 253         self.share_info = new_share_info
 254         self.merkle_branch = merkle_branch
 255         self.other_txs = other_txs
 256
 257         self.share_data = self.share_info['new_share_data']
 258         self.target = self.share_info['target']
 259
 260         self.new_script = self.share_data['new_script']
 261         self.subsidy = self.share_data['subsidy']
 262         self.timestamp = self.share_data['timestamp']
 263
 264         if len(self.new_script) > 100:
 265             raise ValueError('new_script too long!')
 266
 267         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 268         self.nonce = self.share_data['nonce']
 269
 270         if len(self.nonce) > 100:
 271             raise ValueError('nonce too long!')
 272
 273         if len(self.share_data['coinbase']) > 100:
 274             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 275
 276         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 277         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 278
 279         self.hash = new_share1a_type.hash256(self.as_share1a())
 280
 281         if self.pow_hash > self.target:
 282             print 'hash %x' % self.pow_hash
 283             print 'targ %x' % self.target
 284             raise ValueError('not enough work!')
 285
 286         if script.get_sigop_count(self.new_script) > 1:
 287             raise ValueError('too many sigops!')
 288
 289         # XXX eww
 290         self.time_seen = time.time()
 291         self.shared = False
 292         self.stored = False
 293         self.peer = None
 294
 295     def check(self, tracker, now, net):
 296         if self.previous_share_hash is not None:
 297             previous_share = tracker.shares[self.previous_share_hash]
 298             if not (previous_share.timestamp - 60 <= self.timestamp <= previous_share.timestamp + 60):
 299                 raise ValueError('share timestamp (%i) too far from previous timestamp (%i)' % (self.timestamp, previous_share.timestamp))
 300
 301         new_share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
 302         if new_share_info != self.share_info:
 303             raise ValueError('share difficulty invalid')
 304
 305         if bitcoin_data.check_merkle_branch(gentx, 0, self.merkle_branch) != self.header['merkle_root']:
 306             raise ValueError('''gentx doesn't match header via merkle_branch''')
 307
 308         if self.other_txs is not None:
 309             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 310                 raise ValueError('''gentx doesn't match header via other_txs''')
 311
 312             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 313                 raise ValueError('block size too large')
 314
 315 def get_pool_attempts_per_second(tracker, previous_share_hash, net, dist=None):
 316     if dist is None:
 317         dist = net.TARGET_LOOKBEHIND
 318     near = tracker.shares[previous_share_hash]
 319     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 320     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
 321     time = near.timestamp - far.timestamp
 322     if time == 0:
 323         time = 1
 324     return attempts//time
 325
 326 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
 327     height, last = tracker.get_height_and_last(previous_share_hash)
 328     assert height >= net.CHAIN_LENGTH or last is None
 329     if height < net.TARGET_LOOKBEHIND:
 330         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 331     else:
 332         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 333         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 334         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 335         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 336         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 337         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 338
 339     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 340     max_weight = 65535 * net.SPREAD * attempts_to_block
 341
 342     this_weight = 65535 * min(bitcoin_data.target_to_average_attempts(target), max_weight)
 343     other_weights, other_weights_total, other_donation_weight_total = tracker.get_cumulative_weights(previous_share_hash, min(height, net.CHAIN_LENGTH), max(0, max_weight - this_weight))
 344     dest_weights, total_weight, donation_weight_total = math.add_dicts([{new_script: this_weight}, other_weights]), this_weight + other_weights_total, other_donation_weight_total
 345     assert total_weight == sum(dest_weights.itervalues()) + donation_weight_total
 346
 347     if net.SCRIPT:
 348         amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 349         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 350         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
 351         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 352     else:
 353         amounts = dict((script, subsidy*(398*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 354         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 355         amounts[new_script] = amounts.get(new_script, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 356
 357     if sum(amounts.itervalues()) != subsidy:
 358         raise ValueError()
 359     if any(x < 0 for x in amounts.itervalues()):
 360         raise ValueError()
 361
 362     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 363     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 364
 365     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 366     assert dests[-1] == new_script
 367
 368     share_data = dict(
 369         previous_share_hash=previous_share_hash,
 370         nonce=nonce,
 371         target=target,
 372     )
 373
 374     share_info = dict(
 375         share_data=share_data,
 376         new_script=new_script,
 377         subsidy=subsidy,
 378     )
 379
 380     return share_info, dict(
 381         version=1,
 382         tx_ins=[dict(
 383             previous_output=None,
 384             sequence=None,
 385             script=coinbase_type.pack(dict(
 386                 identifier=net.IDENTIFIER,
 387                 share_data=share_data,
 388             )),
 389         )],
 390         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 391         lock_time=0,
 392     )
 393
 394 def new_generate_transaction(tracker, new_share_data, block_target, net):
 395     previous_share_hash = new_share_data['previous_share_hash']
 396     new_script = new_share_data['new_script']
 397     subsidy = new_share_data['subsidy']
 398     donation = new_share_data['donation']
 399     assert 0 <= donation <= 65535
 400
 401     height, last = tracker.get_height_and_last(previous_share_hash)
 402     assert height >= net.CHAIN_LENGTH or last is None
 403     if height < net.TARGET_LOOKBEHIND:
 404         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 405     else:
 406         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 407         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 408         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 409         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 410         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 411         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 412
 413     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 414     max_att = net.SPREAD * attempts_to_block
 415
 416     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
 417     other_weights, other_total_weight, other_donation_weight = tracker.get_cumulative_weights(previous_share_hash, min(height, net.CHAIN_LENGTH), 65535*max(0, max_att - this_att))
 418     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 419     weights, total_weight, donation_weight = math.add_dicts([{new_script: this_att*(65535-donation)}, other_weights]), this_att*65535 + other_total_weight, this_att*donation + other_donation_weight
 420     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 421
 422     amounts = dict((script, subsidy*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
 423     amounts[new_script] = amounts.get(new_script, 0) + subsidy//200
 424     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*(199*donation_weight)//(200*total_weight)
 425     amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
 426
 427     if sum(amounts.itervalues()) != subsidy:
 428         raise ValueError()
 429     if any(x < 0 for x in amounts.itervalues()):
 430         print amounts
 431         import code
 432         d = globals()
 433         d.update(locals())
 434         code.interact(local=d)
 435         raise ValueError()
 436
 437     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 438     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 439
 440     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 441     assert dests[-1] == new_script
 442
 443     new_share_info = dict(
 444         new_share_data=new_share_data,
 445         target=target,
 446     )
 447
 448     return new_share_info, dict(
 449         version=1,
 450         tx_ins=[dict(
 451             previous_output=None,
 452             sequence=None,
 453             script=new_share_data['coinbase'],
 454         )],
 455         tx_outs=[dict(value=0, script=bitcoin_data.HashType().pack(new_share_info_type.hash256(new_share_info)))] + [dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 456         lock_time=0,
 457     )
 458
 459
 460 class OkayTracker(bitcoin_data.Tracker):
 461     def __init__(self, net):
 462         bitcoin_data.Tracker.__init__(self)
 463         self.net = net
 464         self.verified = bitcoin_data.Tracker()
 465         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 466
 467         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 468
 469     def add(self, share, known_verified=False):
 470         bitcoin_data.Tracker.add(self, share)
 471         if known_verified:
 472             self.verified.add(share)
 473
 474     def attempt_verify(self, share, now):
 475         if share.hash in self.verified.shares:
 476             return True
 477         height, last = self.get_height_and_last(share.hash)
 478         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 479             raise AssertionError()
 480         try:
 481             share.check(self, now, self.net)
 482         except:
 483             log.err(None, 'Share check failed:')
 484             return False
 485         else:
 486             self.verified.add(share)
 487             return True
 488
 489     def think(self, ht, previous_block, now):
 490         desired = set()
 491
 492         # O(len(self.heads))
 493         #   make 'unverified heads' set?
 494         # for each overall head, attempt verification
 495         # if it fails, attempt on parent, and repeat
 496         # if no successful verification because of lack of parents, request parent
 497         bads = set()
 498         for head in set(self.heads) - set(self.verified.heads):
 499             head_height, last = self.get_height_and_last(head)
 500
 501             for share in itertools.islice(self.get_chain_known(head), None if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 502                 if self.attempt_verify(share, now):
 503                     break
 504                 if share.hash in self.heads:
 505                     bads.add(share.hash)
 506             else:
 507                 if last is not None:
 508                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
 509         for bad in bads:
 510             assert bad not in self.verified.shares
 511             assert bad in self.heads
 512             if p2pool.DEBUG:
 513                 print "BAD", bad
 514             self.remove(bad)
 515
 516         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 517         for head in list(self.verified.heads):
 518             head_height, last_hash = self.verified.get_height_and_last(head)
 519             last_height, last_last_hash = self.get_height_and_last(last_hash)
 520             # XXX review boundary conditions
 521             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 522             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 523             get = min(want, can)
 524             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 525             for share in itertools.islice(self.get_chain_known(last_hash), get):
 526                 if not self.attempt_verify(share, now):
 527                     break
 528             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 529                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
 530
 531         # decide best tree
 532         best_tail = max(self.verified.tails, key=lambda h: self.score(max(self.verified.tails[h], key=self.verified.get_height), ht)) if self.verified.tails else None
 533         # decide best verified head
 534         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (
 535             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 536             #self.verified.shares[h].peer is None,
 537             ht.get_min_height(self.verified.shares[h].previous_block),
 538             -self.verified.shares[h].time_seen
 539         ))
 540
 541
 542         if p2pool.DEBUG:
 543             print len(self.verified.tails), "chain tails and", len(self.verified.tails.get(best_tail, [])), 'chain heads. Top 10 tails:'
 544             if len(scores) > 10:
 545                 print '    ...'
 546             for h in scores[-10:]:
 547                 print '   ', format_hash(h), format_hash(self.verified.shares[h].previous_hash), (
 548                     self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 549                     self.verified.shares[h].peer is None,
 550                     ht.get_min_height(self.verified.shares[h].previous_block),
 551                     -self.verified.shares[h].time_seen
 552                 )
 553
 554         # eat away at heads
 555         if scores:
 556             for i in xrange(1000):
 557                 to_remove = set()
 558                 for share_hash, tail in self.heads.iteritems():
 559                     if share_hash in scores[-5:]:
 560                         #print 1
 561                         continue
 562                     if self.shares[share_hash].time_seen > time.time() - 300:
 563                         #print 2
 564                         continue
 565                     if share_hash not in self.verified.shares and max(self.shares[after_tail_hash].time_seen for after_tail_hash in self.reverse_shares.get(tail)) > time.time() - 120: # XXX stupid
 566                         #print 3
 567                         continue
 568                     to_remove.add(share_hash)
 569                 if not to_remove:
 570                     break
 571                 for share_hash in to_remove:
 572                     self.remove(share_hash)
 573                     if share_hash in self.verified.shares:
 574                         self.verified.remove(share_hash)
 575                 #print "_________", to_remove
 576
 577         # drop tails
 578         for i in xrange(1000):
 579             to_remove = set()
 580             for tail, heads in self.tails.iteritems():
 581                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 582                     continue
 583                 for aftertail in self.reverse_shares.get(tail, set()):
 584                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 585                         print "raw"
 586                         continue
 587                     to_remove.add(aftertail)
 588             if not to_remove:
 589                 break
 590             # if removed from this, it must be removed from verified
 591             #start = time.time()
 592             for aftertail in to_remove:
 593                 if self.shares[aftertail].previous_hash not in self.tails:
 594                     print "erk", aftertail, self.shares[aftertail].previous_hash
 595                     continue
 596                 self.remove(aftertail)
 597                 if aftertail in self.verified.shares:
 598                     self.verified.remove(aftertail)
 599             #end = time.time()
 600             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 601
 602         best = scores[-1] if scores else None
 603
 604         if best is not None:
 605             best_share = self.verified.shares[best]
 606             if ht.get_min_height(best_share.header['previous_block']) < ht.get_min_height(previous_block) and best_share.header_hash != previous_block and best_share.peer is not None:
 607                 if p2pool.DEBUG:
 608                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 609                 best = best_share.previous_hash
 610
 611         return best, desired
 612
 613     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
 614     def score(self, share_hash, ht):
 615         head_height, last = self.verified.get_height_and_last(share_hash)
 616         score2 = 0
 617         attempts = 0
 618         max_height = 0
 619         share2_hash = self.verified.get_nth_parent_hash(share_hash, min(self.net.CHAIN_LENGTH//2, head_height//2)) if last is not None else share_hash
 620         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
 621             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
 622             attempts += bitcoin_data.target_to_average_attempts(share.target)
 623             this_score = attempts//(ht.get_highest_height() - max_height + 1)
 624             if this_score > score2:
 625                 score2 = this_score
 626         return min(head_height, self.net.CHAIN_LENGTH), score2
 627
 628 def format_hash(x):
 629     if x is None:
 630         return 'xxxxxxxx'
 631     return '%08x' % (x % 2**32)
 632
 633 class ShareStore(object):
 634     def __init__(self, prefix, net):
 635         self.filename = prefix
 636         self.net = net
 637         self.known = None # will be filename -> set of share hashes, set of verified hashes
 638
 639     def get_shares(self):
 640         if self.known is not None:
 641             raise AssertionError()
 642         known = {}
 643         filenames, next = self.get_filenames_and_next()
 644         for filename in filenames:
 645             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 646             with open(filename, 'rb') as f:
 647                 for line in f:
 648                     try:
 649                         type_id_str, data_hex = line.strip().split(' ')
 650                         type_id = int(type_id_str)
 651                         if type_id == 0:
 652                             share = Share.from_share1a(share1a_type.unpack(data_hex.decode('hex')), self.net)
 653                             yield 'share', share
 654                             share_hashes.add(share.hash)
 655                         elif type_id == 1:
 656                             share = Share.from_share1b(share1b_type.unpack(data_hex.decode('hex')), self.net)
 657                             yield 'share', share
 658                             share_hashes.add(share.hash)
 659                         elif type_id == 2:
 660                             verified_hash = int(data_hex, 16)
 661                             yield 'verified_hash', verified_hash
 662                             verified_hashes.add(verified_hash)
 663                         elif type_id == 3:
 664                             share = NewShare.from_share1a(new_share1a_type.unpack(data_hex.decode('hex')), self.net)
 665                             yield 'share', share
 666                             share_hashes.add(share.hash)
 667                         elif type_id == 4:
 668                             share = NewShare.from_share1b(new_share1b_type.unpack(data_hex.decode('hex')), self.net)
 669                             yield 'share', share
 670                             share_hashes.add(share.hash)
 671                         else:
 672                             raise NotImplementedError("share type %i" % (type_id,))
 673                     except Exception:
 674                         log.err(None, "Error while reading saved shares, continuing where left off:")
 675         self.known = known
 676
 677     def _add_line(self, line):
 678         filenames, next = self.get_filenames_and_next()
 679         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 680             filename = filenames[-1]
 681         else:
 682             filename = next
 683
 684         with open(filename, 'ab') as f:
 685             f.write(line + '\n')
 686
 687         return filename
 688
 689     def add_share(self, share):
 690         if isinstance(share, NewShare) and share.pow_hash <= share.header['target']:
 691             type_id, data = 4, new_share1b_type.pack(share.as_share1b())
 692         elif isinstance(share, NewShare):
 693             type_id, data = 3, new_share1a_type.pack(share.as_share1a())
 694         elif share.pow_hash <= share.header['target']:
 695             type_id, data = 1, share1b_type.pack(share.as_share1b())
 696         else:
 697             type_id, data = 0, share1a_type.pack(share.as_share1a())
 698         filename = self._add_line("%i %s" % (type_id, data.encode('hex')))
 699         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 700         share_hashes.add(share.hash)
 701
 702     def add_verified_hash(self, share_hash):
 703         filename = self._add_line("%i %x" % (2, share_hash))
 704         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 705         verified_hashes.add(share_hash)
 706
 707     def get_filenames_and_next(self):
 708         suffixes = sorted(int(x[len(self.filename):]) for x in os.listdir('.') if x.startswith(self.filename) and x[len(self.filename):].isdigit())
 709         return [self.filename + str(suffix) for suffix in suffixes], self.filename + str(suffixes[-1] + 1) if suffixes else self.filename + str(0)
 710
 711     def forget_share(self, share_hash):
 712         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 713             if share_hash in share_hashes:
 714                 share_hashes.remove(share_hash)
 715         self.check_remove()
 716
 717     def forget_verified_share(self, share_hash):
 718         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 719             if share_hash in verified_hashes:
 720                 verified_hashes.remove(share_hash)
 721         self.check_remove()
 722
 723     def check_remove(self):
 724         to_remove = set()
 725         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 726             #print filename, len(share_hashes) + len(verified_hashes)
 727             if not share_hashes and not verified_hashes:
 728                 to_remove.add(filename)
 729         for filename in to_remove:
 730             self.known.pop(filename)
 731             os.remove(filename)
 732             print "REMOVED", filename
 733
 734 class BitcoinMainnet(networks.BitcoinMainnet):
 735     SHARE_PERIOD = 10 # seconds
 736     CHAIN_LENGTH = 24*60*60//5 # shares
 737     TARGET_LOOKBEHIND = 200 # shares
 738     SPREAD = 3 # blocks
 739     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 740     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
 741     PREFIX = '2472ef181efcd37b'.decode('hex')
 742     NAME = 'bitcoin'
 743     P2P_PORT = 9333
 744     MAX_TARGET = 2**256//2**32 - 1
 745     PERSIST = False
 746     WORKER_PORT = 9332
 747
 748 class BitcoinTestnet(networks.BitcoinTestnet):
 749     SHARE_PERIOD = 1 # seconds
 750     CHAIN_LENGTH = 24*60*60//5 # shares
 751     TARGET_LOOKBEHIND = 200 # shares
 752     SPREAD = 3 # blocks
 753     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 754     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
 755     PREFIX = '3f6057a15036f441'.decode('hex')
 756     NAME = 'bitcoin_testnet'
 757     P2P_PORT = 19333
 758     MAX_TARGET = 2**256//2**32 - 1
 759     PERSIST = False
 760     WORKER_PORT = 19332
 761
 762 class NamecoinMainnet(networks.NamecoinMainnet):
 763     SHARE_PERIOD = 10 # seconds
 764     CHAIN_LENGTH = 24*60*60//10 # shares
 765     TARGET_LOOKBEHIND = 3600//10 # shares
 766     SPREAD = 3 # blocks
 767     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 768     IDENTIFIER = 'd5b1192062c4c454'.decode('hex')
 769     PREFIX = 'b56f3d0fb24fc982'.decode('hex')
 770     NAME = 'namecoin'
 771     P2P_PORT = 9334
 772     MAX_TARGET = 2**256//2**32 - 1
 773     PERSIST = True
 774     WORKER_PORT = 9331
 775
 776 class NamecoinTestnet(networks.NamecoinTestnet):
 777     SHARE_PERIOD = 1 # seconds
 778     CHAIN_LENGTH = 24*60*60//5 # shares
 779     TARGET_LOOKBEHIND = 200 # shares
 780     SPREAD = 3 # blocks
 781     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 782     IDENTIFIER = '8dd303d014a01a60'.decode('hex')
 783     PREFIX = '4d6581d24f51acbf'.decode('hex')
 784     NAME = 'namecoin_testnet'
 785     P2P_PORT = 19334
 786     MAX_TARGET = 2**256//2**20 - 1
 787     PERSIST = False
 788     WORKER_PORT = 19331
 789
 790 class IxcoinMainnet(networks.IxcoinMainnet):
 791     SHARE_PERIOD = 10 # seconds
 792     CHAIN_LENGTH = 24*60*60//10 # shares
 793     TARGET_LOOKBEHIND = 3600//10 # shares
 794     SPREAD = 3 # blocks
 795     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 796     IDENTIFIER = '27b564116e2a2666'.decode('hex')
 797     PREFIX = '9dd6c4a619401f2f'.decode('hex')
 798     NAME = 'ixcoin'
 799     P2P_PORT = 9335
 800     MAX_TARGET = 2**256//2**32 - 1
 801     PERSIST = True
 802     WORKER_PORT = 9330
 803
 804 class IxcoinTestnet(networks.IxcoinTestnet):
 805     SHARE_PERIOD = 1 # seconds
 806     CHAIN_LENGTH = 24*60*60//5 # shares
 807     TARGET_LOOKBEHIND = 200 # shares
 808     SPREAD = 3 # blocks
 809     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 810     IDENTIFIER = '7430cbeb01249e44'.decode('hex')
 811     PREFIX = '7cfffda946709c1f'.decode('hex')
 812     NAME = 'ixcoin_testnet'
 813     P2P_PORT = 19335
 814     MAX_TARGET = 2**256//2**20 - 1
 815     PERSIST = False
 816     WORKER_PORT = 19330
 817
 818 class I0coinMainnet(networks.I0coinMainnet):
 819     SHARE_PERIOD = 10 # seconds
 820     CHAIN_LENGTH = 24*60*60//10 # shares
 821     TARGET_LOOKBEHIND = 3600//10 # shares
 822     SPREAD = 3 # blocks
 823     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 824     IDENTIFIER = 'b32e3f10c2ff221b'.decode('hex')
 825     PREFIX = '6155537ed977a3b5'.decode('hex')
 826     NAME = 'i0coin'
 827     P2P_PORT = 9336
 828     MAX_TARGET = 2**256//2**32 - 1
 829     PERSIST = False
 830     WORKER_PORT = 9329
 831
 832 class I0coinTestnet(networks.I0coinTestnet):
 833     SHARE_PERIOD = 1 # seconds
 834     CHAIN_LENGTH = 24*60*60//5 # shares
 835     TARGET_LOOKBEHIND = 200 # shares
 836     SPREAD = 3 # blocks
 837     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 838     IDENTIFIER = '7712c1a8181b5f2e'.decode('hex')
 839     PREFIX = '792d2e7d770fbe68'.decode('hex')
 840     NAME = 'i0coin_testnet'
 841     P2P_PORT = 19336
 842     MAX_TARGET = 2**256//2**20 - 1
 843     PERSIST = False
 844     WORKER_PORT = 19329
 845
 846 class SolidcoinMainnet(networks.SolidcoinMainnet):
 847     SHARE_PERIOD = 10
 848     CHAIN_LENGTH = 24*60*60//10 # shares
 849     TARGET_LOOKBEHIND = 3600//10 # shares
 850     SPREAD = 3 # blocks
 851     SCRIPT = bitcoin_data.pubkey_hash_to_script2(bitcoin_data.address_to_pubkey_hash('sMKZ1yxHETxPYKh4Z2anWnwZDJZU7ztroy', networks.SolidcoinMainnet))
 852     IDENTIFIER = '9cc9c421cca258cd'.decode('hex')
 853     PREFIX = 'c059125b8070f00a'.decode('hex')
 854     NAME = 'solidcoin'
 855     P2P_PORT = 9337
 856     MAX_TARGET = 2**256//2**32 - 1
 857     PERSIST = True
 858     WORKER_PORT = 9328
 859
 860 class LitecoinMainnet(networks.LitecoinMainnet):
 861     SHARE_PERIOD = 10 # seconds
 862     CHAIN_LENGTH = 24*60*60//5 # shares
 863     TARGET_LOOKBEHIND = 200 # shares
 864     SPREAD = 12 # blocks
 865     SCRIPT = None # no fee
 866     IDENTIFIER = 'e037d5b8c6923410'.decode('hex')
 867     PREFIX = '7208c1a53ef629b0'.decode('hex')
 868     NAME = 'litecoin'
 869     P2P_PORT = 9338
 870     MAX_TARGET = 2**256//2**20 - 1
 871     PERSIST = True
 872     WORKER_PORT = 9327
 873
 874 class LitecoinTestnet(networks.LitecoinTestnet):
 875     SHARE_PERIOD = 1 # seconds
 876     CHAIN_LENGTH = 24*60*60//5 # shares
 877     TARGET_LOOKBEHIND = 200 # shares
 878     SPREAD = 12 # blocks
 879     SCRIPT = None # no fee
 880     IDENTIFIER = 'cca5e24ec6408b1e'.decode('hex')
 881     PREFIX = 'ad9614f6466a39cf'.decode('hex')
 882     NAME = 'litecoin_testnet'
 883     P2P_PORT = 19338
 884     MAX_TARGET = 2**256//2**17 - 1
 885     PERSIST = False
 886     WORKER_PORT = 19327
 887
 888 nets = dict((net.NAME, net) for net in set([BitcoinMainnet, BitcoinTestnet, NamecoinMainnet, NamecoinTestnet, IxcoinMainnet, IxcoinTestnet, I0coinMainnet, I0coinTestnet, SolidcoinMainnet, LitecoinMainnet, LitecoinTestnet]))