p2pool/data.py

   1 from __future__ import division
   2
   3 TRANSITION_TIME = 1322638748
   4
   5 import itertools
   6 import random
   7 import time
   8 import os
   9
  10 from twisted.python import log
  11
  12 import p2pool
  13 from p2pool import skiplists
  14 from p2pool.bitcoin import data as bitcoin_data, script, networks
  15 from p2pool.util import memoize, expiring_dict, math
  16
  17
  18 merkle_branch_type = bitcoin_data.ListType(bitcoin_data.ComposedType([
  19     ('side', bitcoin_data.StructType('<B')), # enum?
  20     ('hash', bitcoin_data.HashType()),
  21 ]))
  22
  23
  24 share_data_type = bitcoin_data.ComposedType([
  25     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  26     ('target', bitcoin_data.FloatingIntegerType()),
  27     ('nonce', bitcoin_data.VarStrType()),
  28 ])
  29
  30
  31 coinbase_type = bitcoin_data.ComposedType([
  32     ('identifier', bitcoin_data.FixedStrType(8)),
  33     ('share_data', share_data_type),
  34 ])
  35
  36 share_info_type = bitcoin_data.ComposedType([
  37     ('share_data', share_data_type),
  38     ('new_script', bitcoin_data.VarStrType()),
  39     ('subsidy', bitcoin_data.StructType('<Q')),
  40 ])
  41
  42
  43 share1a_type = bitcoin_data.ComposedType([
  44     ('header', bitcoin_data.block_header_type),
  45     ('share_info', share_info_type),
  46     ('merkle_branch', merkle_branch_type),
  47 ])
  48
  49 share1b_type = bitcoin_data.ComposedType([
  50     ('header', bitcoin_data.block_header_type),
  51     ('share_info', share_info_type),
  52     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  53 ])
  54
  55 new_share_data_type = bitcoin_data.ComposedType([
  56     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  57     ('coinbase', bitcoin_data.VarStrType()),
  58     ('nonce', bitcoin_data.VarStrType()),
  59     ('new_script', bitcoin_data.VarStrType()),
  60     ('subsidy', bitcoin_data.StructType('<Q')),
  61     ('donation', bitcoin_data.StructType('<H')),
  62     ('timestamp', bitcoin_data.StructType('<I')),
  63     ('stale_frac', bitcoin_data.StructType('<B')),
  64 ])
  65
  66 new_share_info_type = bitcoin_data.ComposedType([
  67     ('new_share_data', new_share_data_type),
  68     ('target', bitcoin_data.FloatingIntegerType()),
  69 ])
  70
  71 new_share1a_type = bitcoin_data.ComposedType([
  72     ('header', bitcoin_data.block_header_type),
  73     ('share_info', new_share_info_type),
  74     ('merkle_branch', bitcoin_data.merkle_branch_type),
  75 ])
  76
  77 new_share1b_type = bitcoin_data.ComposedType([
  78     ('header', bitcoin_data.block_header_type),
  79     ('share_info', new_share_info_type),
  80     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  81 ])
  82
  83 # type:
  84 # 0: new_share1a
  85 # 1: new_share1b
  86
  87 new_share_type = bitcoin_data.ComposedType([
  88     ('type', bitcoin_data.VarIntType()),
  89     ('contents', bitcoin_data.VarStrType()),
  90 ])
  91
  92 def calculate_merkle_branch(txs, index):
  93     hash_list = [(bitcoin_data.tx_type.hash256(tx), i == index, []) for i, tx in enumerate(txs)]
  94
  95     while len(hash_list) > 1:
  96         hash_list = [
  97             (
  98                 bitcoin_data.merkle_record_type.hash256(dict(left=left, right=right)),
  99                 left_f or right_f,
 100                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
 101             )
 102             for (left, left_f, left_l), (right, right_f, right_l) in
 103                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
 104         ]
 105
 106     assert hash_list[0][1]
 107     assert check_merkle_branch(txs[index], hash_list[0][2]) == hash_list[0][0]
 108
 109     return hash_list[0][2]
 110
 111 def check_merkle_branch(tx, branch):
 112     hash_ = bitcoin_data.tx_type.hash256(tx)
 113     for step in branch:
 114         if not step['side']:
 115             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=step['hash'], right=hash_))
 116         else:
 117             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=hash_, right=step['hash']))
 118     return hash_
 119
 120 def share_info_to_gentx(share_info, block_target, tracker, net):
 121     return generate_transaction(
 122         tracker=tracker,
 123         previous_share_hash=share_info['share_data']['previous_share_hash'],
 124         new_script=share_info['new_script'],
 125         subsidy=share_info['subsidy'],
 126         nonce=share_info['share_data']['nonce'],
 127         block_target=block_target,
 128         net=net,
 129     )[1]
 130
 131 class Share(object):
 132     donation = 0
 133
 134     @classmethod
 135     def from_share1a(cls, share1a, net):
 136         return cls(net, **share1a)
 137
 138     @classmethod
 139     def from_share1b(cls, share1b, net):
 140         return cls(net, **share1b)
 141
 142     __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(' ')
 143
 144     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 145         if header['timestamp'] >= TRANSITION_TIME:
 146             raise AssertionError('transitioning...')
 147         if merkle_branch is None and other_txs is None:
 148             raise ValueError('need either merkle_branch or other_txs')
 149         if other_txs is not None:
 150             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 151             if merkle_branch is not None:
 152                 if merke_branch != new_merkle_branch:
 153                     raise ValueError('invalid merkle_branch and other_txs')
 154             merkle_branch = new_merkle_branch
 155
 156         if len(merkle_branch) > 16:
 157             raise ValueError('merkle_branch too long!')
 158
 159         self.header = header
 160         self.previous_block = header['previous_block']
 161         self.share_info = share_info
 162         self.merkle_branch = merkle_branch
 163         self.other_txs = other_txs
 164
 165         self.timestamp = self.header['timestamp']
 166
 167         self.share_data = self.share_info['share_data']
 168         self.new_script = self.share_info['new_script']
 169         self.subsidy = self.share_info['subsidy']
 170
 171         if len(self.new_script) > 100:
 172             raise ValueError('new_script too long!')
 173
 174         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 175         self.target = self.share_data['target']
 176         self.nonce = self.share_data['nonce']
 177
 178         if len(self.nonce) > 100:
 179             raise ValueError('nonce too long!')
 180
 181         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 182         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 183
 184         if net.BITCOIN_POW_FUNC == bitcoin_data.block_header_type.scrypt:
 185             # compatibility hack
 186             self.hash = share1a_type.scrypt(self.as_share1a())
 187         else:
 188             self.hash = share1a_type.hash256(self.as_share1a())
 189
 190         if self.pow_hash > self.target:
 191             print 'hash %x' % self.pow_hash
 192             print 'targ %x' % self.target
 193             raise ValueError('not enough work!')
 194
 195         if script.get_sigop_count(self.new_script) > 1:
 196             raise ValueError('too many sigops!')
 197
 198         # XXX eww
 199         self.time_seen = time.time()
 200         self.shared = False
 201         self.stored = False
 202         self.peer = None
 203
 204     def as_block(self, tracker, net):
 205         if self.other_txs is None:
 206             raise ValueError('share does not contain all txs')
 207
 208         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 209
 210         return dict(header=self.header, txs=[gentx] + self.other_txs)
 211
 212     def as_share1a(self):
 213         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 214
 215     def as_share1b(self):
 216         if self.other_txs is None:
 217             raise ValueError('share does not contain all txs')
 218
 219         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 220
 221     def check(self, tracker, now, net):
 222         import time
 223         if self.previous_share_hash is not None:
 224             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):
 225                 raise ValueError('share from too far in the past!')
 226
 227         if self.header['timestamp'] > now + 2*60*60:
 228             raise ValueError('share from too far in the future!')
 229
 230         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 231
 232         if len(gentx['tx_ins'][0]['script']) > 100:
 233             raise ValueError('coinbase too large! %i bytes' % (len(gentx['tx_ins'][0]['script']),))
 234
 235         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
 236             raise ValueError('''gentx doesn't match header via merkle_branch''')
 237
 238         if self.other_txs is not None:
 239             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 240                 raise ValueError('''gentx doesn't match header via other_txs''')
 241
 242             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 243                 raise ValueError('block size too large')
 244
 245     def flag_shared(self):
 246         self.shared = True
 247
 248     def __repr__(self):
 249         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 250
 251 class NewShare(Share):
 252     @classmethod
 253     def from_share(cls, share, net):
 254         if share['type'] == 0:
 255             res = cls.from_share1a(new_share1a_type.unpack(share['contents']), net)
 256             if not (res.pow_hash > res.header['target']):
 257                 raise ValueError('invalid share type')
 258             return res
 259         elif share['type'] == 1:
 260             res = cls.from_share1b(new_share1b_type.unpack(share['contents']), net)
 261             if not (res.pow_hash <= res.header['target']):
 262                 raise ValueError('invalid share type')
 263             return res
 264         else:
 265             raise ValueError('unknown share type: %r' % (share['type'],))
 266
 267     def as_share(self):
 268         if self.pow_hash > self.header['target']: # new_share1a
 269             return dict(type=0, contents=new_share1a_type.pack(self.as_share1a()))
 270         elif self.pow_hash <= self.header['target']: # new_share1b
 271             return dict(type=1, contents=new_share1b_type.pack(self.as_share1b()))
 272         else:
 273             raise AssertionError()
 274
 275     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 276         if header['timestamp'] < TRANSITION_TIME:
 277             raise AssertionError('transitioning...')
 278         if merkle_branch is None and other_txs is None:
 279             raise ValueError('need either merkle_branch or other_txs')
 280         if other_txs is not None:
 281             new_merkle_branch = bitcoin_data.calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 282             if merkle_branch is not None:
 283                 if merke_branch != new_merkle_branch:
 284                     raise ValueError('invalid merkle_branch and other_txs')
 285             merkle_branch = new_merkle_branch
 286
 287         if len(merkle_branch) > 16:
 288             raise ValueError('merkle_branch too long!')
 289
 290         self.header = header
 291         self.previous_block = header['previous_block']
 292         self.share_info = share_info
 293         self.merkle_branch = merkle_branch
 294         self.other_txs = other_txs
 295
 296         self.share_data = self.share_info['new_share_data']
 297         self.target = self.share_info['target']
 298
 299         self.new_script = self.share_data['new_script']
 300         self.subsidy = self.share_data['subsidy']
 301         self.timestamp = self.share_data['timestamp']
 302
 303         if len(self.new_script) > 100:
 304             raise ValueError('new_script too long!')
 305
 306         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 307         self.nonce = self.share_data['nonce']
 308
 309         if len(self.nonce) > 100:
 310             raise ValueError('nonce too long!')
 311
 312         if len(self.share_data['coinbase']) > 100:
 313             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 314
 315         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 316         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 317
 318         self.hash = new_share1a_type.hash256(self.as_share1a())
 319
 320         if self.pow_hash > self.target:
 321             print 'hash %x' % self.pow_hash
 322             print 'targ %x' % self.target
 323             raise ValueError('not enough work!')
 324
 325         if script.get_sigop_count(self.new_script) > 1:
 326             raise ValueError('too many sigops!')
 327
 328         # XXX eww
 329         self.time_seen = time.time()
 330         self.shared = False
 331         self.stored = False
 332         self.peer = None
 333
 334     def check(self, tracker, now, net):
 335         if self.previous_share_hash is not None:
 336             previous_share = tracker.shares[self.previous_share_hash]
 337             if not (previous_share.timestamp - 60 <= self.timestamp <= previous_share.timestamp + 60):
 338                 raise ValueError('share timestamp (%i) too far from previous timestamp (%i)' % (self.timestamp, previous_share.timestamp))
 339
 340         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
 341         if share_info != self.share_info:
 342             raise ValueError('share difficulty invalid')
 343
 344         if bitcoin_data.check_merkle_branch(gentx, 0, self.merkle_branch) != self.header['merkle_root']:
 345             raise ValueError('''gentx doesn't match header via merkle_branch''')
 346
 347     def as_block(self, tracker, net):
 348         if self.other_txs is None:
 349             raise ValueError('share does not contain all txs')
 350
 351         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
 352         assert share_info == self.share_info
 353
 354         return dict(header=self.header, txs=[gentx] + self.other_txs)
 355
 356 def get_pool_attempts_per_second(tracker, previous_share_hash, net, dist=None):
 357     if dist is None:
 358         dist = net.TARGET_LOOKBEHIND
 359     near = tracker.shares[previous_share_hash]
 360     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 361     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
 362     time = near.timestamp - far.timestamp
 363     if time == 0:
 364         time = 1
 365     return attempts//time
 366
 367 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
 368     height, last = tracker.get_height_and_last(previous_share_hash)
 369     assert height >= net.CHAIN_LENGTH or last is None
 370     if height < net.TARGET_LOOKBEHIND:
 371         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 372     else:
 373         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 374         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 375         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 376         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 377         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 378         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 379
 380     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 381     max_weight = 65535 * net.SPREAD * attempts_to_block
 382
 383     this_weight = 65535 * min(bitcoin_data.target_to_average_attempts(target), max_weight)
 384     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))
 385     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
 386     assert total_weight == sum(dest_weights.itervalues()) + donation_weight_total
 387
 388     if net.SCRIPT:
 389         amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 390         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 391         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
 392         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 393     else:
 394         amounts = dict((script, subsidy*(398*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 395         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 396         amounts[new_script] = amounts.get(new_script, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 397
 398     if sum(amounts.itervalues()) != subsidy:
 399         raise ValueError()
 400     if any(x < 0 for x in amounts.itervalues()):
 401         raise ValueError()
 402
 403     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 404     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 405
 406     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 407     assert dests[-1] == new_script
 408
 409     share_data = dict(
 410         previous_share_hash=previous_share_hash,
 411         nonce=nonce,
 412         target=target,
 413     )
 414
 415     share_info = dict(
 416         share_data=share_data,
 417         new_script=new_script,
 418         subsidy=subsidy,
 419     )
 420
 421     return share_info, dict(
 422         version=1,
 423         tx_ins=[dict(
 424             previous_output=None,
 425             sequence=None,
 426             script=coinbase_type.pack(dict(
 427                 identifier=net.IDENTIFIER,
 428                 share_data=share_data,
 429             )),
 430         )],
 431         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 432         lock_time=0,
 433     )
 434
 435 def new_generate_transaction(tracker, new_share_data, block_target, net):
 436     previous_share_hash = new_share_data['previous_share_hash']
 437     new_script = new_share_data['new_script']
 438     subsidy = new_share_data['subsidy']
 439     donation = new_share_data['donation']
 440     assert 0 <= donation <= 65535
 441
 442     height, last = tracker.get_height_and_last(previous_share_hash)
 443     assert height >= net.CHAIN_LENGTH or last is None
 444     if height < net.TARGET_LOOKBEHIND:
 445         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 446     else:
 447         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 448         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 449         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 450         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 451         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 452         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 453
 454     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 455     max_att = net.SPREAD * attempts_to_block
 456
 457     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
 458     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))
 459     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 460     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
 461     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 462
 463     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 464
 465     amounts = dict((script, subsidy*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
 466     amounts[new_script] = amounts.get(new_script, 0) + subsidy//200
 467     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy*(199*donation_weight)//(200*total_weight)
 468     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
 469
 470     if sum(amounts.itervalues()) != subsidy:
 471         raise ValueError()
 472     if any(x < 0 for x in amounts.itervalues()):
 473         print amounts
 474         import code
 475         d = globals()
 476         d.update(locals())
 477         code.interact(local=d)
 478         raise ValueError()
 479
 480     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 481     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 482
 483     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 484     assert dests[-1] == new_script
 485
 486     share_info = dict(
 487         new_share_data=new_share_data,
 488         target=target,
 489     )
 490
 491     return share_info, dict(
 492         version=1,
 493         tx_ins=[dict(
 494             previous_output=None,
 495             sequence=None,
 496             script=new_share_data['coinbase'],
 497         )],
 498         tx_outs=[dict(value=0, script=bitcoin_data.HashType().pack(new_share_info_type.hash256(share_info)))] + [dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 499         lock_time=0,
 500     )
 501
 502
 503 class OkayTracker(bitcoin_data.Tracker):
 504     def __init__(self, net):
 505         bitcoin_data.Tracker.__init__(self)
 506         self.net = net
 507         self.verified = bitcoin_data.Tracker()
 508         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 509
 510         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 511
 512     def add(self, share, known_verified=False):
 513         bitcoin_data.Tracker.add(self, share)
 514         if known_verified:
 515             self.verified.add(share)
 516
 517     def attempt_verify(self, share, now):
 518         if share.hash in self.verified.shares:
 519             return True
 520         height, last = self.get_height_and_last(share.hash)
 521         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 522             raise AssertionError()
 523         try:
 524             share.check(self, now, self.net)
 525         except:
 526             log.err(None, 'Share check failed:')
 527             return False
 528         else:
 529             self.verified.add(share)
 530             return True
 531
 532     def think(self, ht, previous_block, now):
 533         desired = set()
 534
 535         # O(len(self.heads))
 536         #   make 'unverified heads' set?
 537         # for each overall head, attempt verification
 538         # if it fails, attempt on parent, and repeat
 539         # if no successful verification because of lack of parents, request parent
 540         bads = set()
 541         for head in set(self.heads) - set(self.verified.heads):
 542             head_height, last = self.get_height_and_last(head)
 543
 544             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))):
 545                 if self.attempt_verify(share, now):
 546                     break
 547                 if share.hash in self.heads:
 548                     bads.add(share.hash)
 549             else:
 550                 if last is not None:
 551                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
 552         for bad in bads:
 553             assert bad not in self.verified.shares
 554             assert bad in self.heads
 555             if p2pool.DEBUG:
 556                 print "BAD", bad
 557             self.remove(bad)
 558
 559         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 560         for head in list(self.verified.heads):
 561             head_height, last_hash = self.verified.get_height_and_last(head)
 562             last_height, last_last_hash = self.get_height_and_last(last_hash)
 563             # XXX review boundary conditions
 564             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 565             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 566             get = min(want, can)
 567             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 568             for share in itertools.islice(self.get_chain_known(last_hash), get):
 569                 if not self.attempt_verify(share, now):
 570                     break
 571             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 572                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
 573
 574         # decide best tree
 575         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
 576         # decide best verified head
 577         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (
 578             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 579             #self.verified.shares[h].peer is None,
 580             ht.get_min_height(self.verified.shares[h].previous_block),
 581             -self.verified.shares[h].time_seen
 582         ))
 583
 584
 585         if p2pool.DEBUG:
 586             print len(self.verified.tails), "chain tails and", len(self.verified.tails.get(best_tail, [])), 'chain heads. Top 10 tails:'
 587             if len(scores) > 10:
 588                 print '    ...'
 589             for h in scores[-10:]:
 590                 print '   ', format_hash(h), format_hash(self.verified.shares[h].previous_hash), (
 591                     self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 592                     self.verified.shares[h].peer is None,
 593                     ht.get_min_height(self.verified.shares[h].previous_block),
 594                     -self.verified.shares[h].time_seen
 595                 )
 596
 597         # eat away at heads
 598         if scores:
 599             for i in xrange(1000):
 600                 to_remove = set()
 601                 for share_hash, tail in self.heads.iteritems():
 602                     if share_hash in scores[-5:]:
 603                         #print 1
 604                         continue
 605                     if self.shares[share_hash].time_seen > time.time() - 300:
 606                         #print 2
 607                         continue
 608                     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
 609                         #print 3
 610                         continue
 611                     to_remove.add(share_hash)
 612                 if not to_remove:
 613                     break
 614                 for share_hash in to_remove:
 615                     self.remove(share_hash)
 616                     if share_hash in self.verified.shares:
 617                         self.verified.remove(share_hash)
 618                 #print "_________", to_remove
 619
 620         # drop tails
 621         for i in xrange(1000):
 622             to_remove = set()
 623             for tail, heads in self.tails.iteritems():
 624                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 625                     continue
 626                 for aftertail in self.reverse_shares.get(tail, set()):
 627                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 628                         print "raw"
 629                         continue
 630                     to_remove.add(aftertail)
 631             if not to_remove:
 632                 break
 633             # if removed from this, it must be removed from verified
 634             #start = time.time()
 635             for aftertail in to_remove:
 636                 if self.shares[aftertail].previous_hash not in self.tails:
 637                     print "erk", aftertail, self.shares[aftertail].previous_hash
 638                     continue
 639                 self.remove(aftertail)
 640                 if aftertail in self.verified.shares:
 641                     self.verified.remove(aftertail)
 642             #end = time.time()
 643             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 644
 645         best = scores[-1] if scores else None
 646
 647         if best is not None:
 648             best_share = self.verified.shares[best]
 649             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:
 650                 if p2pool.DEBUG:
 651                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 652                 best = best_share.previous_hash
 653
 654         return best, desired
 655
 656     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
 657     def score(self, share_hash, ht):
 658         head_height, last = self.verified.get_height_and_last(share_hash)
 659         score2 = 0
 660         attempts = 0
 661         max_height = 0
 662         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
 663         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
 664             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
 665             attempts += bitcoin_data.target_to_average_attempts(share.target)
 666             this_score = attempts//(ht.get_highest_height() - max_height + 1)
 667             if this_score > score2:
 668                 score2 = this_score
 669         return min(head_height, self.net.CHAIN_LENGTH), score2
 670
 671 def format_hash(x):
 672     if x is None:
 673         return 'xxxxxxxx'
 674     return '%08x' % (x % 2**32)
 675
 676 class ShareStore(object):
 677     def __init__(self, prefix, net):
 678         self.filename = prefix
 679         self.dirname = os.path.dirname(os.path.abspath(prefix))
 680         self.filename = os.path.basename(os.path.abspath(prefix))
 681         self.net = net
 682         self.known = None # will be filename -> set of share hashes, set of verified hashes
 683
 684     def get_shares(self):
 685         if self.known is not None:
 686             raise AssertionError()
 687         known = {}
 688         filenames, next = self.get_filenames_and_next()
 689         for filename in filenames:
 690             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 691             with open(filename, 'rb') as f:
 692                 for line in f:
 693                     try:
 694                         type_id_str, data_hex = line.strip().split(' ')
 695                         type_id = int(type_id_str)
 696                         if type_id == 0:
 697                             share = Share.from_share1a(share1a_type.unpack(data_hex.decode('hex')), self.net)
 698                             yield 'share', share
 699                             share_hashes.add(share.hash)
 700                         elif type_id == 1:
 701                             share = Share.from_share1b(share1b_type.unpack(data_hex.decode('hex')), self.net)
 702                             yield 'share', share
 703                             share_hashes.add(share.hash)
 704                         elif type_id == 2:
 705                             verified_hash = int(data_hex, 16)
 706                             yield 'verified_hash', verified_hash
 707                             verified_hashes.add(verified_hash)
 708                         elif type_id == 5:
 709                             share = NewShare.from_share(new_share_type.unpack(data_hex.decode('hex')), self.net)
 710                             yield 'share', share
 711                             share_hashes.add(share.hash)
 712                         else:
 713                             raise NotImplementedError("share type %i" % (type_id,))
 714                     except Exception:
 715                         log.err(None, "Error while reading saved shares, continuing where left off:")
 716         self.known = known
 717
 718     def _add_line(self, line):
 719         filenames, next = self.get_filenames_and_next()
 720         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 721             filename = filenames[-1]
 722         else:
 723             filename = next
 724
 725         with open(filename, 'ab') as f:
 726             f.write(line + '\n')
 727
 728         return filename
 729
 730     def add_share(self, share):
 731         if isinstance(share, NewShare):
 732             type_id, data = 5, new_share_type.pack(share.as_share())
 733         elif share.pow_hash <= share.header['target']:
 734             type_id, data = 1, share1b_type.pack(share.as_share1b())
 735         else:
 736             type_id, data = 0, share1a_type.pack(share.as_share1a())
 737         filename = self._add_line("%i %s" % (type_id, data.encode('hex')))
 738         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 739         share_hashes.add(share.hash)
 740
 741     def add_verified_hash(self, share_hash):
 742         filename = self._add_line("%i %x" % (2, share_hash))
 743         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 744         verified_hashes.add(share_hash)
 745
 746     def get_filenames_and_next(self):
 747         suffixes = sorted(int(x[len(self.filename):]) for x in os.listdir(self.dirname) if x.startswith(self.filename) and x[len(self.filename):].isdigit())
 748         return [os.path.join(self.dirname, self.filename + str(suffix)) for suffix in suffixes], os.path.join(self.dirname, self.filename + (str(suffixes[-1] + 1) if suffixes else str(0)))
 749
 750     def forget_share(self, share_hash):
 751         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 752             if share_hash in share_hashes:
 753                 share_hashes.remove(share_hash)
 754         self.check_remove()
 755
 756     def forget_verified_share(self, share_hash):
 757         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 758             if share_hash in verified_hashes:
 759                 verified_hashes.remove(share_hash)
 760         self.check_remove()
 761
 762     def check_remove(self):
 763         to_remove = set()
 764         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 765             #print filename, len(share_hashes) + len(verified_hashes)
 766             if not share_hashes and not verified_hashes:
 767                 to_remove.add(filename)
 768         for filename in to_remove:
 769             self.known.pop(filename)
 770             os.remove(filename)
 771             print "REMOVED", filename
 772
 773 class BitcoinMainnet(networks.BitcoinMainnet):
 774     SHARE_PERIOD = 10 # seconds
 775     CHAIN_LENGTH = 24*60*60//5 # shares
 776     TARGET_LOOKBEHIND = 200 # shares
 777     SPREAD = 3 # blocks
 778     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 779     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
 780     PREFIX = '2472ef181efcd37b'.decode('hex')
 781     NAME = 'bitcoin'
 782     P2P_PORT = 9333
 783     MAX_TARGET = 2**256//2**32 - 1
 784     PERSIST = False
 785     WORKER_PORT = 9332
 786
 787 class BitcoinTestnet(networks.BitcoinTestnet):
 788     SHARE_PERIOD = 1 # seconds
 789     CHAIN_LENGTH = 24*60*60//5 # shares
 790     TARGET_LOOKBEHIND = 200 # shares
 791     SPREAD = 3 # blocks
 792     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 793     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
 794     PREFIX = '3f6057a15036f441'.decode('hex')
 795     NAME = 'bitcoin_testnet'
 796     P2P_PORT = 19333
 797     MAX_TARGET = 2**256//2**32 - 1
 798     PERSIST = False
 799     WORKER_PORT = 19332
 800
 801 class NamecoinMainnet(networks.NamecoinMainnet):
 802     SHARE_PERIOD = 10 # seconds
 803     CHAIN_LENGTH = 24*60*60//10 # shares
 804     TARGET_LOOKBEHIND = 3600//10 # shares
 805     SPREAD = 3 # blocks
 806     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 807     IDENTIFIER = 'd5b1192062c4c454'.decode('hex')
 808     PREFIX = 'b56f3d0fb24fc982'.decode('hex')
 809     NAME = 'namecoin'
 810     P2P_PORT = 9334
 811     MAX_TARGET = 2**256//2**32 - 1
 812     PERSIST = True
 813     WORKER_PORT = 9331
 814
 815 class NamecoinTestnet(networks.NamecoinTestnet):
 816     SHARE_PERIOD = 1 # seconds
 817     CHAIN_LENGTH = 24*60*60//5 # shares
 818     TARGET_LOOKBEHIND = 200 # shares
 819     SPREAD = 3 # blocks
 820     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 821     IDENTIFIER = '8dd303d014a01a60'.decode('hex')
 822     PREFIX = '4d6581d24f51acbf'.decode('hex')
 823     NAME = 'namecoin_testnet'
 824     P2P_PORT = 19334
 825     MAX_TARGET = 2**256//2**20 - 1
 826     PERSIST = False
 827     WORKER_PORT = 19331
 828
 829 class IxcoinMainnet(networks.IxcoinMainnet):
 830     SHARE_PERIOD = 10 # seconds
 831     CHAIN_LENGTH = 24*60*60//10 # shares
 832     TARGET_LOOKBEHIND = 3600//10 # shares
 833     SPREAD = 3 # blocks
 834     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 835     IDENTIFIER = '27b564116e2a2666'.decode('hex')
 836     PREFIX = '9dd6c4a619401f2f'.decode('hex')
 837     NAME = 'ixcoin'
 838     P2P_PORT = 9335
 839     MAX_TARGET = 2**256//2**32 - 1
 840     PERSIST = True
 841     WORKER_PORT = 9330
 842
 843 class IxcoinTestnet(networks.IxcoinTestnet):
 844     SHARE_PERIOD = 1 # seconds
 845     CHAIN_LENGTH = 24*60*60//5 # shares
 846     TARGET_LOOKBEHIND = 200 # shares
 847     SPREAD = 3 # blocks
 848     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 849     IDENTIFIER = '7430cbeb01249e44'.decode('hex')
 850     PREFIX = '7cfffda946709c1f'.decode('hex')
 851     NAME = 'ixcoin_testnet'
 852     P2P_PORT = 19335
 853     MAX_TARGET = 2**256//2**20 - 1
 854     PERSIST = False
 855     WORKER_PORT = 19330
 856
 857 class I0coinMainnet(networks.I0coinMainnet):
 858     SHARE_PERIOD = 10 # seconds
 859     CHAIN_LENGTH = 24*60*60//10 # shares
 860     TARGET_LOOKBEHIND = 3600//10 # shares
 861     SPREAD = 3 # blocks
 862     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 863     IDENTIFIER = 'b32e3f10c2ff221b'.decode('hex')
 864     PREFIX = '6155537ed977a3b5'.decode('hex')
 865     NAME = 'i0coin'
 866     P2P_PORT = 9336
 867     MAX_TARGET = 2**256//2**32 - 1
 868     PERSIST = False
 869     WORKER_PORT = 9329
 870
 871 class I0coinTestnet(networks.I0coinTestnet):
 872     SHARE_PERIOD = 1 # seconds
 873     CHAIN_LENGTH = 24*60*60//5 # shares
 874     TARGET_LOOKBEHIND = 200 # shares
 875     SPREAD = 3 # blocks
 876     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 877     IDENTIFIER = '7712c1a8181b5f2e'.decode('hex')
 878     PREFIX = '792d2e7d770fbe68'.decode('hex')
 879     NAME = 'i0coin_testnet'
 880     P2P_PORT = 19336
 881     MAX_TARGET = 2**256//2**20 - 1
 882     PERSIST = False
 883     WORKER_PORT = 19329
 884
 885 class SolidcoinMainnet(networks.SolidcoinMainnet):
 886     SHARE_PERIOD = 10
 887     CHAIN_LENGTH = 24*60*60//10 # shares
 888     TARGET_LOOKBEHIND = 3600//10 # shares
 889     SPREAD = 3 # blocks
 890     SCRIPT = bitcoin_data.pubkey_hash_to_script2(bitcoin_data.address_to_pubkey_hash('sMKZ1yxHETxPYKh4Z2anWnwZDJZU7ztroy', networks.SolidcoinMainnet))
 891     IDENTIFIER = '9cc9c421cca258cd'.decode('hex')
 892     PREFIX = 'c059125b8070f00a'.decode('hex')
 893     NAME = 'solidcoin'
 894     P2P_PORT = 9337
 895     MAX_TARGET = 2**256//2**32 - 1
 896     PERSIST = True
 897     WORKER_PORT = 9328
 898
 899 class LitecoinMainnet(networks.LitecoinMainnet):
 900     SHARE_PERIOD = 10 # seconds
 901     CHAIN_LENGTH = 24*60*60//5 # shares
 902     TARGET_LOOKBEHIND = 200 # shares
 903     SPREAD = 12 # blocks
 904     SCRIPT = None # no fee
 905     IDENTIFIER = 'e037d5b8c6923410'.decode('hex')
 906     PREFIX = '7208c1a53ef629b0'.decode('hex')
 907     NAME = 'litecoin'
 908     P2P_PORT = 9338
 909     MAX_TARGET = 2**256//2**20 - 1
 910     PERSIST = True
 911     WORKER_PORT = 9327
 912
 913 class LitecoinTestnet(networks.LitecoinTestnet):
 914     SHARE_PERIOD = 1 # seconds
 915     CHAIN_LENGTH = 24*60*60//5 # shares
 916     TARGET_LOOKBEHIND = 200 # shares
 917     SPREAD = 12 # blocks
 918     SCRIPT = None # no fee
 919     IDENTIFIER = 'cca5e24ec6408b1e'.decode('hex')
 920     PREFIX = 'ad9614f6466a39cf'.decode('hex')
 921     NAME = 'litecoin_testnet'
 922     P2P_PORT = 19338
 923     MAX_TARGET = 2**256//2**17 - 1
 924     PERSIST = False
 925     WORKER_PORT = 19327
 926
 927 nets = dict((net.NAME, net) for net in set([BitcoinMainnet, BitcoinTestnet, NamecoinMainnet, NamecoinTestnet, IxcoinMainnet, IxcoinTestnet, I0coinMainnet, I0coinTestnet, SolidcoinMainnet, LitecoinMainnet, LitecoinTestnet]))