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 = int(0.005*65535 + 0.5)
 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 peer'.split(' ')
 143
 144     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 145         if merkle_branch is None and other_txs is None:
 146             raise ValueError('need either merkle_branch or other_txs')
 147         if other_txs is not None:
 148             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 149             if merkle_branch is not None:
 150                 if merke_branch != new_merkle_branch:
 151                     raise ValueError('invalid merkle_branch and other_txs')
 152             merkle_branch = new_merkle_branch
 153
 154         if len(merkle_branch) > 16:
 155             raise ValueError('merkle_branch too long!')
 156
 157         self.header = header
 158         self.previous_block = header['previous_block']
 159         self.share_info = share_info
 160         self.merkle_branch = merkle_branch
 161         self.other_txs = other_txs
 162
 163         self.timestamp = self.header['timestamp']
 164
 165         self.share_data = self.share_info['share_data']
 166         self.new_script = self.share_info['new_script']
 167         self.subsidy = self.share_info['subsidy']
 168
 169         if len(self.new_script) > 100:
 170             raise ValueError('new_script too long!')
 171
 172         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 173         self.target = self.share_data['target']
 174         self.nonce = self.share_data['nonce']
 175
 176         if len(self.nonce) > 100:
 177             raise ValueError('nonce too long!')
 178
 179         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 180         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 181
 182         if net.BITCOIN_POW_FUNC == bitcoin_data.block_header_type.scrypt:
 183             # compatibility hack
 184             self.hash = share1a_type.scrypt(self.as_share1a())
 185         else:
 186             self.hash = share1a_type.hash256(self.as_share1a())
 187
 188         if self.pow_hash > self.target:
 189             print 'hash %x' % self.pow_hash
 190             print 'targ %x' % self.target
 191             raise ValueError('not enough work!')
 192
 193         if script.get_sigop_count(self.new_script) > 1:
 194             raise ValueError('too many sigops!')
 195
 196         # XXX eww
 197         self.time_seen = time.time()
 198         self.peer = None
 199
 200     def as_block(self, tracker, net):
 201         if self.other_txs is None:
 202             raise ValueError('share does not contain all txs')
 203
 204         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 205
 206         return dict(header=self.header, txs=[gentx] + self.other_txs)
 207
 208     def as_share1a(self):
 209         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 210
 211     def as_share1b(self):
 212         if self.other_txs is None:
 213             raise ValueError('share does not contain all txs')
 214
 215         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 216
 217     def check(self, tracker, now, net):
 218         if self.header['timestamp'] >= TRANSITION_TIME:
 219             raise AssertionError('transitioning...')
 220         import time
 221         if self.previous_share_hash is not None:
 222             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):
 223                 raise ValueError('share from too far in the past!')
 224
 225         if self.header['timestamp'] > now + 2*60*60:
 226             raise ValueError('share from too far in the future!')
 227
 228         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 229
 230         if len(gentx['tx_ins'][0]['script']) > 100:
 231             raise ValueError('coinbase too large! %i bytes' % (len(gentx['tx_ins'][0]['script']),))
 232
 233         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
 234             raise ValueError('''gentx doesn't match header via merkle_branch''')
 235
 236         if self.other_txs is not None:
 237             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 238                 raise ValueError('''gentx doesn't match header via other_txs''')
 239
 240             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 241                 raise ValueError('block size too large')
 242
 243     def __repr__(self):
 244         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 245
 246 class NewShare(Share):
 247     @classmethod
 248     def from_share(cls, share, net):
 249         if share['type'] == 0:
 250             res = cls.from_share1a(new_share1a_type.unpack(share['contents']), net)
 251             if not (res.pow_hash > res.header['target']):
 252                 raise ValueError('invalid share type')
 253             return res
 254         elif share['type'] == 1:
 255             res = cls.from_share1b(new_share1b_type.unpack(share['contents']), net)
 256             if not (res.pow_hash <= res.header['target']):
 257                 raise ValueError('invalid share type')
 258             return res
 259         else:
 260             raise ValueError('unknown share type: %r' % (share['type'],))
 261
 262     def as_share(self):
 263         if self.pow_hash > self.header['target']: # new_share1a
 264             return dict(type=0, contents=new_share1a_type.pack(self.as_share1a()))
 265         elif self.pow_hash <= self.header['target']: # new_share1b
 266             return dict(type=1, contents=new_share1b_type.pack(self.as_share1b()))
 267         else:
 268             raise AssertionError()
 269
 270     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 271         if merkle_branch is None and other_txs is None:
 272             raise ValueError('need either merkle_branch or other_txs')
 273         if other_txs is not None:
 274             new_merkle_branch = bitcoin_data.calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 275             if merkle_branch is not None:
 276                 if merke_branch != new_merkle_branch:
 277                     raise ValueError('invalid merkle_branch and other_txs')
 278             merkle_branch = new_merkle_branch
 279
 280         if len(merkle_branch) > 16:
 281             raise ValueError('merkle_branch too long!')
 282
 283         self.header = header
 284         self.previous_block = header['previous_block']
 285         self.share_info = share_info
 286         self.merkle_branch = merkle_branch
 287         self.other_txs = other_txs
 288
 289         self.share_data = self.share_info['new_share_data']
 290         self.target = self.share_info['target']
 291
 292         self.new_script = self.share_data['new_script']
 293         self.subsidy = self.share_data['subsidy']
 294         self.timestamp = self.share_data['timestamp']
 295
 296         if len(self.new_script) > 100:
 297             raise ValueError('new_script too long!')
 298
 299         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 300         self.nonce = self.share_data['nonce']
 301
 302         if len(self.nonce) > 100:
 303             raise ValueError('nonce too long!')
 304
 305         if len(self.share_data['coinbase']) > 100:
 306             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 307
 308         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 309         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 310
 311         self.hash = new_share1a_type.hash256(self.as_share1a())
 312
 313         if self.pow_hash > self.target:
 314             print 'hash %x' % self.pow_hash
 315             print 'targ %x' % self.target
 316             raise ValueError('not enough work!')
 317
 318         if script.get_sigop_count(self.new_script) > 1:
 319             raise ValueError('too many sigops!')
 320
 321         # XXX eww
 322         self.time_seen = time.time()
 323         self.peer = None
 324
 325     def check(self, tracker, now, net):
 326         if self.header['timestamp'] < TRANSITION_TIME:
 327             raise AssertionError('transitioning...')
 328         if self.previous_share_hash is not None:
 329             previous_share = tracker.shares[self.previous_share_hash]
 330             if not (previous_share.timestamp - 60 <= self.timestamp <= previous_share.timestamp + 60):
 331                 raise ValueError('share timestamp (%i) too far from previous timestamp (%i)' % (self.timestamp, previous_share.timestamp))
 332
 333         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
 334         if share_info != self.share_info:
 335             raise ValueError('share difficulty invalid')
 336
 337         if bitcoin_data.check_merkle_branch(gentx, 0, self.merkle_branch) != self.header['merkle_root']:
 338             raise ValueError('''gentx doesn't match header via merkle_branch''')
 339
 340     def as_block(self, tracker, net):
 341         if self.other_txs is None:
 342             raise ValueError('share does not contain all txs')
 343
 344         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], net)
 345         assert share_info == self.share_info
 346
 347         return dict(header=self.header, txs=[gentx] + self.other_txs)
 348
 349 def get_pool_attempts_per_second(tracker, previous_share_hash, net, dist=None):
 350     if dist is None:
 351         dist = net.TARGET_LOOKBEHIND
 352     near = tracker.shares[previous_share_hash]
 353     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 354     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
 355     time = near.timestamp - far.timestamp
 356     if time == 0:
 357         time = 1
 358     return attempts//time
 359
 360 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
 361     height, last = tracker.get_height_and_last(previous_share_hash)
 362     assert height >= net.CHAIN_LENGTH or last is None
 363     if height < net.TARGET_LOOKBEHIND:
 364         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 365     else:
 366         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 367         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 368         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 369         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 370         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 371         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 372
 373     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 374     max_weight = 65535 * net.SPREAD * attempts_to_block
 375
 376     this_weight = 65535 * min(bitcoin_data.target_to_average_attempts(target), max_weight)
 377     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))
 378     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
 379     assert total_weight == sum(dest_weights.itervalues()) + donation_weight_total
 380
 381     total_weight -= donation_weight_total # ignore donation
 382
 383     if net.SCRIPT:
 384         amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in dest_weights.iteritems())
 385         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 386         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
 387         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 388     else:
 389         amounts = dict((script, subsidy*(398*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[new_script] = amounts.get(new_script, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 392
 393     if sum(amounts.itervalues()) != subsidy:
 394         raise ValueError()
 395     if any(x < 0 for x in amounts.itervalues()):
 396         raise ValueError()
 397
 398     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 399     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 400
 401     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 402     assert dests[-1] == new_script
 403
 404     share_data = dict(
 405         previous_share_hash=previous_share_hash,
 406         nonce=nonce,
 407         target=target,
 408     )
 409
 410     share_info = dict(
 411         share_data=share_data,
 412         new_script=new_script,
 413         subsidy=subsidy,
 414     )
 415
 416     return share_info, dict(
 417         version=1,
 418         tx_ins=[dict(
 419             previous_output=None,
 420             sequence=None,
 421             script=coinbase_type.pack(dict(
 422                 identifier=net.IDENTIFIER,
 423                 share_data=share_data,
 424             )),
 425         )],
 426         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 427         lock_time=0,
 428     )
 429
 430 def new_generate_transaction(tracker, new_share_data, block_target, net):
 431     previous_share_hash = new_share_data['previous_share_hash']
 432     new_script = new_share_data['new_script']
 433     subsidy = new_share_data['subsidy']
 434     donation = new_share_data['donation']
 435     assert 0 <= donation <= 65535
 436
 437     if len(new_share_data['coinbase']) > 100:
 438         raise ValueError('coinbase too long!')
 439
 440     height, last = tracker.get_height_and_last(previous_share_hash)
 441     assert height >= net.CHAIN_LENGTH or last is None
 442     if height < net.TARGET_LOOKBEHIND:
 443         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 444     else:
 445         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 446         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 447         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 448         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 449         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 450         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 451
 452     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 453     max_att = net.SPREAD * attempts_to_block
 454
 455     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
 456     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))
 457     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 458     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
 459     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 460
 461     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 462
 463     amounts = dict((script, subsidy*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
 464     amounts[new_script] = amounts.get(new_script, 0) + subsidy//200
 465     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy*(199*donation_weight)//(200*total_weight)
 466     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
 467
 468     if sum(amounts.itervalues()) != subsidy:
 469         raise ValueError()
 470     if any(x < 0 for x in amounts.itervalues()):
 471         print amounts
 472         import code
 473         d = globals()
 474         d.update(locals())
 475         code.interact(local=d)
 476         raise ValueError()
 477
 478     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 479     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 480
 481     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 482     assert dests[-1] == new_script
 483
 484     share_info = dict(
 485         new_share_data=new_share_data,
 486         target=target,
 487     )
 488
 489     return share_info, dict(
 490         version=1,
 491         tx_ins=[dict(
 492             previous_output=None,
 493             sequence=None,
 494             script=new_share_data['coinbase'].ljust(2, '\x00'),
 495         )],
 496         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]],
 497         lock_time=0,
 498     )
 499
 500
 501 class OkayTracker(bitcoin_data.Tracker):
 502     def __init__(self, net):
 503         bitcoin_data.Tracker.__init__(self)
 504         self.net = net
 505         self.verified = bitcoin_data.Tracker()
 506         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 507
 508         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 509
 510     def add(self, share, known_verified=False):
 511         bitcoin_data.Tracker.add(self, share)
 512         if known_verified:
 513             self.verified.add(share)
 514
 515     def attempt_verify(self, share, now):
 516         if share.hash in self.verified.shares:
 517             return True
 518         height, last = self.get_height_and_last(share.hash)
 519         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 520             raise AssertionError()
 521         try:
 522             share.check(self, now, self.net)
 523         except:
 524             log.err(None, 'Share check failed:')
 525             return False
 526         else:
 527             self.verified.add(share)
 528             return True
 529
 530     def think(self, ht, previous_block, now):
 531         desired = set()
 532
 533         # O(len(self.heads))
 534         #   make 'unverified heads' set?
 535         # for each overall head, attempt verification
 536         # if it fails, attempt on parent, and repeat
 537         # if no successful verification because of lack of parents, request parent
 538         bads = set()
 539         for head in set(self.heads) - set(self.verified.heads):
 540             head_height, last = self.get_height_and_last(head)
 541
 542             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))):
 543                 if self.attempt_verify(share, now):
 544                     break
 545                 if share.hash in self.heads:
 546                     bads.add(share.hash)
 547             else:
 548                 if last is not None:
 549                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
 550         for bad in bads:
 551             assert bad not in self.verified.shares
 552             assert bad in self.heads
 553             if p2pool.DEBUG:
 554                 print "BAD", bad
 555             self.remove(bad)
 556
 557         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 558         for head in list(self.verified.heads):
 559             head_height, last_hash = self.verified.get_height_and_last(head)
 560             last_height, last_last_hash = self.get_height_and_last(last_hash)
 561             # XXX review boundary conditions
 562             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 563             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 564             get = min(want, can)
 565             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 566             for share in itertools.islice(self.get_chain_known(last_hash), get):
 567                 if not self.attempt_verify(share, now):
 568                     break
 569             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 570                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
 571
 572         # decide best tree
 573         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
 574         # decide best verified head
 575         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (
 576             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 577             #self.verified.shares[h].peer is None,
 578             ht.get_min_height(self.verified.shares[h].previous_block),
 579             -self.verified.shares[h].time_seen
 580         ))
 581
 582
 583         if p2pool.DEBUG:
 584             print len(self.verified.tails), "chain tails and", len(self.verified.tails.get(best_tail, [])), 'chain heads. Top 10 tails:'
 585             if len(scores) > 10:
 586                 print '    ...'
 587             for h in scores[-10:]:
 588                 print '   ', format_hash(h), format_hash(self.verified.shares[h].previous_hash), (
 589                     self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 590                     self.verified.shares[h].peer is None,
 591                     ht.get_min_height(self.verified.shares[h].previous_block),
 592                     -self.verified.shares[h].time_seen
 593                 )
 594
 595         # eat away at heads
 596         if scores:
 597             for i in xrange(1000):
 598                 to_remove = set()
 599                 for share_hash, tail in self.heads.iteritems():
 600                     if share_hash in scores[-5:]:
 601                         #print 1
 602                         continue
 603                     if self.shares[share_hash].time_seen > time.time() - 300:
 604                         #print 2
 605                         continue
 606                     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
 607                         #print 3
 608                         continue
 609                     to_remove.add(share_hash)
 610                 if not to_remove:
 611                     break
 612                 for share_hash in to_remove:
 613                     self.remove(share_hash)
 614                     if share_hash in self.verified.shares:
 615                         self.verified.remove(share_hash)
 616                 #print "_________", to_remove
 617
 618         # drop tails
 619         for i in xrange(1000):
 620             to_remove = set()
 621             for tail, heads in self.tails.iteritems():
 622                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 623                     continue
 624                 for aftertail in self.reverse_shares.get(tail, set()):
 625                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 626                         print "raw"
 627                         continue
 628                     to_remove.add(aftertail)
 629             if not to_remove:
 630                 break
 631             # if removed from this, it must be removed from verified
 632             #start = time.time()
 633             for aftertail in to_remove:
 634                 if self.shares[aftertail].previous_hash not in self.tails:
 635                     print "erk", aftertail, self.shares[aftertail].previous_hash
 636                     continue
 637                 self.remove(aftertail)
 638                 if aftertail in self.verified.shares:
 639                     self.verified.remove(aftertail)
 640             #end = time.time()
 641             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 642
 643         best = scores[-1] if scores else None
 644
 645         if best is not None:
 646             best_share = self.verified.shares[best]
 647             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:
 648                 if p2pool.DEBUG:
 649                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 650                 best = best_share.previous_hash
 651
 652         return best, desired
 653
 654     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
 655     def score(self, share_hash, ht):
 656         head_height, last = self.verified.get_height_and_last(share_hash)
 657         score2 = 0
 658         attempts = 0
 659         max_height = 0
 660         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
 661         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
 662             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
 663             attempts += bitcoin_data.target_to_average_attempts(share.target)
 664             this_score = attempts//(ht.get_highest_height() - max_height + 1)
 665             if this_score > score2:
 666                 score2 = this_score
 667         return min(head_height, self.net.CHAIN_LENGTH), score2
 668
 669 def format_hash(x):
 670     if x is None:
 671         return 'xxxxxxxx'
 672     return '%08x' % (x % 2**32)
 673
 674 class ShareStore(object):
 675     def __init__(self, prefix, net):
 676         self.filename = prefix
 677         self.dirname = os.path.dirname(os.path.abspath(prefix))
 678         self.filename = os.path.basename(os.path.abspath(prefix))
 679         self.net = net
 680         self.known = None # will be filename -> set of share hashes, set of verified hashes
 681
 682     def get_shares(self):
 683         if self.known is not None:
 684             raise AssertionError()
 685         known = {}
 686         filenames, next = self.get_filenames_and_next()
 687         for filename in filenames:
 688             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 689             with open(filename, 'rb') as f:
 690                 for line in f:
 691                     try:
 692                         type_id_str, data_hex = line.strip().split(' ')
 693                         type_id = int(type_id_str)
 694                         if type_id == 0:
 695                             share = Share.from_share1a(share1a_type.unpack(data_hex.decode('hex')), self.net)
 696                             yield 'share', share
 697                             share_hashes.add(share.hash)
 698                         elif type_id == 1:
 699                             share = Share.from_share1b(share1b_type.unpack(data_hex.decode('hex')), self.net)
 700                             yield 'share', share
 701                             share_hashes.add(share.hash)
 702                         elif type_id == 2:
 703                             verified_hash = int(data_hex, 16)
 704                             yield 'verified_hash', verified_hash
 705                             verified_hashes.add(verified_hash)
 706                         elif type_id == 5:
 707                             share = NewShare.from_share(new_share_type.unpack(data_hex.decode('hex')), self.net)
 708                             yield 'share', share
 709                             share_hashes.add(share.hash)
 710                         else:
 711                             raise NotImplementedError("share type %i" % (type_id,))
 712                     except Exception:
 713                         log.err(None, "Error while reading saved shares, continuing where left off:")
 714         self.known = known
 715
 716     def _add_line(self, line):
 717         filenames, next = self.get_filenames_and_next()
 718         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 719             filename = filenames[-1]
 720         else:
 721             filename = next
 722
 723         with open(filename, 'ab') as f:
 724             f.write(line + '\n')
 725
 726         return filename
 727
 728     def add_share(self, share):
 729         if isinstance(share, NewShare):
 730             type_id, data = 5, new_share_type.pack(share.as_share())
 731         elif share.pow_hash <= share.header['target']:
 732             type_id, data = 1, share1b_type.pack(share.as_share1b())
 733         else:
 734             type_id, data = 0, share1a_type.pack(share.as_share1a())
 735         filename = self._add_line("%i %s" % (type_id, data.encode('hex')))
 736         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 737         share_hashes.add(share.hash)
 738
 739     def add_verified_hash(self, share_hash):
 740         filename = self._add_line("%i %x" % (2, share_hash))
 741         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 742         verified_hashes.add(share_hash)
 743
 744     def get_filenames_and_next(self):
 745         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())
 746         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)))
 747
 748     def forget_share(self, share_hash):
 749         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 750             if share_hash in share_hashes:
 751                 share_hashes.remove(share_hash)
 752         self.check_remove()
 753
 754     def forget_verified_share(self, share_hash):
 755         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 756             if share_hash in verified_hashes:
 757                 verified_hashes.remove(share_hash)
 758         self.check_remove()
 759
 760     def check_remove(self):
 761         to_remove = set()
 762         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 763             #print filename, len(share_hashes) + len(verified_hashes)
 764             if not share_hashes and not verified_hashes:
 765                 to_remove.add(filename)
 766         for filename in to_remove:
 767             self.known.pop(filename)
 768             os.remove(filename)
 769             print "REMOVED", filename
 770
 771 class BitcoinMainnet(networks.BitcoinMainnet):
 772     SHARE_PERIOD = 10 # seconds
 773     CHAIN_LENGTH = 24*60*60//5 # shares
 774     TARGET_LOOKBEHIND = 200 # shares
 775     SPREAD = 3 # blocks
 776     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 777     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
 778     PREFIX = '2472ef181efcd37b'.decode('hex')
 779     NAME = 'bitcoin'
 780     P2P_PORT = 9333
 781     MAX_TARGET = 2**256//2**32 - 1
 782     PERSIST = False
 783     WORKER_PORT = 9332
 784
 785 class BitcoinTestnet(networks.BitcoinTestnet):
 786     SHARE_PERIOD = 1 # seconds
 787     CHAIN_LENGTH = 24*60*60//5 # shares
 788     TARGET_LOOKBEHIND = 200 # shares
 789     SPREAD = 3 # blocks
 790     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 791     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
 792     PREFIX = '3f6057a15036f441'.decode('hex')
 793     NAME = 'bitcoin_testnet'
 794     P2P_PORT = 19333
 795     MAX_TARGET = 2**256//2**32 - 1
 796     PERSIST = False
 797     WORKER_PORT = 19332
 798
 799 class NamecoinMainnet(networks.NamecoinMainnet):
 800     SHARE_PERIOD = 10 # seconds
 801     CHAIN_LENGTH = 24*60*60//10 # shares
 802     TARGET_LOOKBEHIND = 3600//10 # shares
 803     SPREAD = 3 # blocks
 804     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 805     IDENTIFIER = 'd5b1192062c4c454'.decode('hex')
 806     PREFIX = 'b56f3d0fb24fc982'.decode('hex')
 807     NAME = 'namecoin'
 808     P2P_PORT = 9334
 809     MAX_TARGET = 2**256//2**32 - 1
 810     PERSIST = True
 811     WORKER_PORT = 9331
 812
 813 class NamecoinTestnet(networks.NamecoinTestnet):
 814     SHARE_PERIOD = 1 # seconds
 815     CHAIN_LENGTH = 24*60*60//5 # shares
 816     TARGET_LOOKBEHIND = 200 # shares
 817     SPREAD = 3 # blocks
 818     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 819     IDENTIFIER = '8dd303d014a01a60'.decode('hex')
 820     PREFIX = '4d6581d24f51acbf'.decode('hex')
 821     NAME = 'namecoin_testnet'
 822     P2P_PORT = 19334
 823     MAX_TARGET = 2**256//2**20 - 1
 824     PERSIST = False
 825     WORKER_PORT = 19331
 826
 827 class IxcoinMainnet(networks.IxcoinMainnet):
 828     SHARE_PERIOD = 10 # seconds
 829     CHAIN_LENGTH = 24*60*60//10 # shares
 830     TARGET_LOOKBEHIND = 3600//10 # shares
 831     SPREAD = 3 # blocks
 832     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 833     IDENTIFIER = '27b564116e2a2666'.decode('hex')
 834     PREFIX = '9dd6c4a619401f2f'.decode('hex')
 835     NAME = 'ixcoin'
 836     P2P_PORT = 9335
 837     MAX_TARGET = 2**256//2**32 - 1
 838     PERSIST = True
 839     WORKER_PORT = 9330
 840
 841 class IxcoinTestnet(networks.IxcoinTestnet):
 842     SHARE_PERIOD = 1 # seconds
 843     CHAIN_LENGTH = 24*60*60//5 # shares
 844     TARGET_LOOKBEHIND = 200 # shares
 845     SPREAD = 3 # blocks
 846     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 847     IDENTIFIER = '7430cbeb01249e44'.decode('hex')
 848     PREFIX = '7cfffda946709c1f'.decode('hex')
 849     NAME = 'ixcoin_testnet'
 850     P2P_PORT = 19335
 851     MAX_TARGET = 2**256//2**20 - 1
 852     PERSIST = False
 853     WORKER_PORT = 19330
 854
 855 class I0coinMainnet(networks.I0coinMainnet):
 856     SHARE_PERIOD = 10 # seconds
 857     CHAIN_LENGTH = 24*60*60//10 # shares
 858     TARGET_LOOKBEHIND = 3600//10 # shares
 859     SPREAD = 3 # blocks
 860     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 861     IDENTIFIER = 'b32e3f10c2ff221b'.decode('hex')
 862     PREFIX = '6155537ed977a3b5'.decode('hex')
 863     NAME = 'i0coin'
 864     P2P_PORT = 9336
 865     MAX_TARGET = 2**256//2**32 - 1
 866     PERSIST = False
 867     WORKER_PORT = 9329
 868
 869 class I0coinTestnet(networks.I0coinTestnet):
 870     SHARE_PERIOD = 1 # seconds
 871     CHAIN_LENGTH = 24*60*60//5 # shares
 872     TARGET_LOOKBEHIND = 200 # shares
 873     SPREAD = 3 # blocks
 874     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 875     IDENTIFIER = '7712c1a8181b5f2e'.decode('hex')
 876     PREFIX = '792d2e7d770fbe68'.decode('hex')
 877     NAME = 'i0coin_testnet'
 878     P2P_PORT = 19336
 879     MAX_TARGET = 2**256//2**20 - 1
 880     PERSIST = False
 881     WORKER_PORT = 19329
 882
 883 class SolidcoinMainnet(networks.SolidcoinMainnet):
 884     SHARE_PERIOD = 10
 885     CHAIN_LENGTH = 24*60*60//10 # shares
 886     TARGET_LOOKBEHIND = 3600//10 # shares
 887     SPREAD = 3 # blocks
 888     SCRIPT = bitcoin_data.pubkey_hash_to_script2(bitcoin_data.address_to_pubkey_hash('sMKZ1yxHETxPYKh4Z2anWnwZDJZU7ztroy', networks.SolidcoinMainnet))
 889     IDENTIFIER = '9cc9c421cca258cd'.decode('hex')
 890     PREFIX = 'c059125b8070f00a'.decode('hex')
 891     NAME = 'solidcoin'
 892     P2P_PORT = 9337
 893     MAX_TARGET = 2**256//2**32 - 1
 894     PERSIST = True
 895     WORKER_PORT = 9328
 896
 897 class LitecoinMainnet(networks.LitecoinMainnet):
 898     SHARE_PERIOD = 10 # seconds
 899     CHAIN_LENGTH = 24*60*60//5 # shares
 900     TARGET_LOOKBEHIND = 200 # shares
 901     SPREAD = 12 # blocks
 902     SCRIPT = None # no fee
 903     IDENTIFIER = 'e037d5b8c6923410'.decode('hex')
 904     PREFIX = '7208c1a53ef629b0'.decode('hex')
 905     NAME = 'litecoin'
 906     P2P_PORT = 9338
 907     MAX_TARGET = 2**256//2**20 - 1
 908     PERSIST = True
 909     WORKER_PORT = 9327
 910
 911 class LitecoinTestnet(networks.LitecoinTestnet):
 912     SHARE_PERIOD = 1 # seconds
 913     CHAIN_LENGTH = 24*60*60//5 # shares
 914     TARGET_LOOKBEHIND = 200 # shares
 915     SPREAD = 12 # blocks
 916     SCRIPT = None # no fee
 917     IDENTIFIER = 'cca5e24ec6408b1e'.decode('hex')
 918     PREFIX = 'ad9614f6466a39cf'.decode('hex')
 919     NAME = 'litecoin_testnet'
 920     P2P_PORT = 19338
 921     MAX_TARGET = 2**256//2**17 - 1
 922     PERSIST = False
 923     WORKER_PORT = 19327
 924
 925 nets = dict((net.NAME, net) for net in set([BitcoinMainnet, BitcoinTestnet, NamecoinMainnet, NamecoinTestnet, IxcoinMainnet, IxcoinTestnet, I0coinMainnet, I0coinTestnet, SolidcoinMainnet, LitecoinMainnet, LitecoinTestnet]))