p2pool/data.py

   1 from __future__ import division
   2
   3 TRANSITION_TIME = 1322804365
   4
   5 import itertools
   6 import random
   7 import time
   8 import os
   9 import struct
  10
  11 from twisted.python import log
  12
  13 import p2pool
  14 from p2pool import skiplists
  15 from p2pool.bitcoin import data as bitcoin_data, script, networks
  16 from p2pool.util import memoize, expiring_dict, math
  17
  18
  19 merkle_branch_type = bitcoin_data.ListType(bitcoin_data.ComposedType([
  20     ('side', bitcoin_data.StructType('<B')), # enum?
  21     ('hash', bitcoin_data.HashType()),
  22 ]))
  23
  24
  25 share_data_type = bitcoin_data.ComposedType([
  26     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  27     ('target', bitcoin_data.FloatingIntegerType()),
  28     ('nonce', bitcoin_data.VarStrType()),
  29 ])
  30
  31
  32 coinbase_type = bitcoin_data.ComposedType([
  33     ('identifier', bitcoin_data.FixedStrType(8)),
  34     ('share_data', share_data_type),
  35 ])
  36
  37 share_info_type = bitcoin_data.ComposedType([
  38     ('share_data', share_data_type),
  39     ('new_script', bitcoin_data.VarStrType()),
  40     ('subsidy', bitcoin_data.StructType('<Q')),
  41 ])
  42
  43
  44 share1a_type = bitcoin_data.ComposedType([
  45     ('header', bitcoin_data.block_header_type),
  46     ('share_info', share_info_type),
  47     ('merkle_branch', merkle_branch_type),
  48 ])
  49
  50 share1b_type = bitcoin_data.ComposedType([
  51     ('header', bitcoin_data.block_header_type),
  52     ('share_info', share_info_type),
  53     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  54 ])
  55
  56 new_share_data_type = bitcoin_data.ComposedType([
  57     ('previous_share_hash', bitcoin_data.PossiblyNoneType(0, bitcoin_data.HashType())),
  58     ('coinbase', bitcoin_data.VarStrType()),
  59     ('nonce', bitcoin_data.VarStrType()),
  60     ('new_script', bitcoin_data.VarStrType()),
  61     ('subsidy', bitcoin_data.StructType('<Q')),
  62     ('donation', bitcoin_data.StructType('<H')),
  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     ('timestamp', bitcoin_data.StructType('<I')),
  70 ])
  71
  72 new_share1a_type = bitcoin_data.ComposedType([
  73     ('header', bitcoin_data.block_header_type),
  74     ('share_info', new_share_info_type),
  75     ('merkle_branch', bitcoin_data.merkle_branch_type),
  76 ])
  77
  78 new_share1b_type = bitcoin_data.ComposedType([
  79     ('header', bitcoin_data.block_header_type),
  80     ('share_info', new_share_info_type),
  81     ('other_txs', bitcoin_data.ListType(bitcoin_data.tx_type)),
  82 ])
  83
  84 # type:
  85 # 0: new_share1a
  86 # 1: new_share1b
  87
  88 new_share_type = bitcoin_data.ComposedType([
  89     ('type', bitcoin_data.VarIntType()),
  90     ('contents', bitcoin_data.VarStrType()),
  91 ])
  92
  93 def calculate_merkle_branch(txs, index):
  94     hash_list = [(bitcoin_data.tx_type.hash256(tx), i == index, []) for i, tx in enumerate(txs)]
  95
  96     while len(hash_list) > 1:
  97         hash_list = [
  98             (
  99                 bitcoin_data.merkle_record_type.hash256(dict(left=left, right=right)),
 100                 left_f or right_f,
 101                 (left_l if left_f else right_l) + [dict(side=1, hash=right) if left_f else dict(side=0, hash=left)],
 102             )
 103             for (left, left_f, left_l), (right, right_f, right_l) in
 104                 zip(hash_list[::2], hash_list[1::2] + [hash_list[::2][-1]])
 105         ]
 106
 107     assert hash_list[0][1]
 108     assert check_merkle_branch(txs[index], hash_list[0][2]) == hash_list[0][0]
 109
 110     return hash_list[0][2]
 111
 112 def check_merkle_branch(tx, branch):
 113     hash_ = bitcoin_data.tx_type.hash256(tx)
 114     for step in branch:
 115         if not step['side']:
 116             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=step['hash'], right=hash_))
 117         else:
 118             hash_ = bitcoin_data.merkle_record_type.hash256(dict(left=hash_, right=step['hash']))
 119     return hash_
 120
 121 def share_info_to_gentx(share_info, block_target, tracker, net):
 122     return generate_transaction(
 123         tracker=tracker,
 124         previous_share_hash=share_info['share_data']['previous_share_hash'],
 125         new_script=share_info['new_script'],
 126         subsidy=share_info['subsidy'],
 127         nonce=share_info['share_data']['nonce'],
 128         block_target=block_target,
 129         net=net,
 130     )[1]
 131
 132 class Share(object):
 133     donation = int(0.005*65535 + 0.5)
 134
 135     @classmethod
 136     def from_share1a(cls, share1a, net):
 137         return cls(net, **share1a)
 138
 139     @classmethod
 140     def from_share1b(cls, share1b, net):
 141         return cls(net, **share1b)
 142
 143     __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 stale_frac'.split(' ')
 144
 145     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 146         if merkle_branch is None and other_txs is None:
 147             raise ValueError('need either merkle_branch or other_txs')
 148         if other_txs is not None:
 149             new_merkle_branch = calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 150             if merkle_branch is not None:
 151                 if merke_branch != new_merkle_branch:
 152                     raise ValueError('invalid merkle_branch and other_txs')
 153             merkle_branch = new_merkle_branch
 154
 155         if len(merkle_branch) > 16:
 156             raise ValueError('merkle_branch too long!')
 157
 158         self.header = header
 159         self.previous_block = header['previous_block']
 160         self.share_info = share_info
 161         self.merkle_branch = merkle_branch
 162         self.other_txs = other_txs
 163
 164         self.timestamp = self.header['timestamp']
 165
 166         self.share_data = self.share_info['share_data']
 167         self.new_script = self.share_info['new_script']
 168         self.subsidy = self.share_info['subsidy']
 169
 170         if len(self.new_script) > 100:
 171             raise ValueError('new_script too long!')
 172
 173         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 174         self.target = self.share_data['target']
 175         self.nonce = self.share_data['nonce']
 176
 177         if len(self.nonce) > 100:
 178             raise ValueError('nonce too long!')
 179
 180         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 181         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 182
 183         if net.BITCOIN_POW_FUNC == bitcoin_data.block_header_type.scrypt:
 184             # compatibility hack
 185             self.hash = share1a_type.scrypt(self.as_share1a())
 186         else:
 187             self.hash = share1a_type.hash256(self.as_share1a())
 188
 189         if self.pow_hash > self.target:
 190             print 'hash %x' % self.pow_hash
 191             print 'targ %x' % self.target
 192             raise ValueError('not enough work!')
 193
 194         if script.get_sigop_count(self.new_script) > 1:
 195             raise ValueError('too many sigops!')
 196
 197         self.stale_frac = None
 198         if len(self.nonce) >= 4:
 199             a, b = struct.unpack("<HH", self.nonce[-4:])
 200             if a != 0 or a == b:
 201                 self.stale_frac = a/65535
 202
 203         # XXX eww
 204         self.time_seen = time.time()
 205         self.peer = None
 206
 207     def as_block(self, tracker, net):
 208         if self.other_txs is None:
 209             raise ValueError('share does not contain all txs')
 210
 211         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 212
 213         return dict(header=self.header, txs=[gentx] + self.other_txs)
 214
 215     def as_share1a(self):
 216         return dict(header=self.header, share_info=self.share_info, merkle_branch=self.merkle_branch)
 217
 218     def as_share1b(self):
 219         if self.other_txs is None:
 220             raise ValueError('share does not contain all txs')
 221
 222         return dict(header=self.header, share_info=self.share_info, other_txs=self.other_txs)
 223
 224     def check(self, tracker, now, net):
 225         if self.header['timestamp'] >= TRANSITION_TIME + 3600:
 226             raise AssertionError('transitioning...')
 227         import time
 228         if self.previous_share_hash is not None:
 229             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):
 230                 raise ValueError('share from too far in the past!')
 231
 232         if self.header['timestamp'] > now + 2*60*60:
 233             raise ValueError('share from too far in the future!')
 234
 235         gentx = share_info_to_gentx(self.share_info, self.header['target'], tracker, net)
 236
 237         if len(gentx['tx_ins'][0]['script']) > 100:
 238             raise ValueError('coinbase too large! %i bytes' % (len(gentx['tx_ins'][0]['script']),))
 239
 240         if check_merkle_branch(gentx, self.merkle_branch) != self.header['merkle_root']:
 241             raise ValueError('''gentx doesn't match header via merkle_branch''')
 242
 243         if self.other_txs is not None:
 244             if bitcoin_data.merkle_hash([gentx] + self.other_txs) != self.header['merkle_root']:
 245                 raise ValueError('''gentx doesn't match header via other_txs''')
 246
 247             if len(bitcoin_data.block_type.pack(dict(header=self.header, txs=[gentx] + self.other_txs))) > 1000000 - 1000:
 248                 raise ValueError('block size too large')
 249
 250     def __repr__(self):
 251         return '<Share %s>' % (' '.join('%s=%r' % (k, getattr(self, k)) for k in self.__slots__),)
 252
 253 class NewShare(Share):
 254     __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 donation stale_frac'.split(' ')
 255
 256     @classmethod
 257     def from_share(cls, share, net):
 258         if share['type'] == 0:
 259             res = cls.from_share1a(new_share1a_type.unpack(share['contents']), net)
 260             if not (res.pow_hash > res.header['target']):
 261                 raise ValueError('invalid share type')
 262             return res
 263         elif share['type'] == 1:
 264             res = cls.from_share1b(new_share1b_type.unpack(share['contents']), net)
 265             if not (res.pow_hash <= res.header['target']):
 266                 raise ValueError('invalid share type')
 267             return res
 268         else:
 269             raise ValueError('unknown share type: %r' % (share['type'],))
 270
 271     def as_share(self):
 272         if self.pow_hash > self.header['target']: # new_share1a
 273             return dict(type=0, contents=new_share1a_type.pack(self.as_share1a()))
 274         elif self.pow_hash <= self.header['target']: # new_share1b
 275             return dict(type=1, contents=new_share1b_type.pack(self.as_share1b()))
 276         else:
 277             raise AssertionError()
 278
 279     def __init__(self, net, header, share_info, merkle_branch=None, other_txs=None):
 280         if merkle_branch is None and other_txs is None:
 281             raise ValueError('need either merkle_branch or other_txs')
 282         if other_txs is not None:
 283             new_merkle_branch = bitcoin_data.calculate_merkle_branch([dict(version=0, tx_ins=[], tx_outs=[], lock_time=0)] + other_txs, 0)
 284             if merkle_branch is not None:
 285                 if merke_branch != new_merkle_branch:
 286                     raise ValueError('invalid merkle_branch and other_txs')
 287             merkle_branch = new_merkle_branch
 288
 289         if len(merkle_branch) > 16:
 290             raise ValueError('merkle_branch too long!')
 291
 292         self.header = header
 293         self.previous_block = header['previous_block']
 294         self.share_info = share_info
 295         self.merkle_branch = merkle_branch
 296         self.other_txs = other_txs
 297
 298         self.share_data = self.share_info['new_share_data']
 299         self.target = self.share_info['target']
 300         self.timestamp = self.share_info['timestamp']
 301
 302         self.new_script = self.share_data['new_script']
 303         self.subsidy = self.share_data['subsidy']
 304         self.donation = self.share_data['donation']
 305
 306         if len(self.new_script) > 100:
 307             raise ValueError('new_script too long!')
 308
 309         self.previous_hash = self.previous_share_hash = self.share_data['previous_share_hash']
 310         self.nonce = self.share_data['nonce']
 311
 312         if len(self.nonce) > 100:
 313             raise ValueError('nonce too long!')
 314
 315         if len(self.share_data['coinbase']) > 100:
 316             raise ValueError('''coinbase too large! %i bytes''' % (len(self.share_data['coinbase']),))
 317
 318         self.pow_hash = net.BITCOIN_POW_FUNC(header)
 319         self.header_hash = bitcoin_data.block_header_type.hash256(header)
 320
 321         self.hash = new_share1a_type.hash256(self.as_share1a())
 322
 323         if self.pow_hash > self.target:
 324             print 'hash %x' % self.pow_hash
 325             print 'targ %x' % self.target
 326             raise ValueError('not enough work!')
 327
 328         if script.get_sigop_count(self.new_script) > 1:
 329             raise ValueError('too many sigops!')
 330
 331         self.stale_frac = self.share_data['stale_frac']/254 if self.share_data['stale_frac'] != 255 else None
 332
 333         # XXX eww
 334         self.time_seen = time.time()
 335         self.peer = None
 336
 337     def check(self, tracker, now, net):
 338         if self.header['timestamp'] <= TRANSITION_TIME - 3600:
 339             raise AssertionError('transitioning...')
 340
 341         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], self.share_info['timestamp'], net)
 342         if share_info != self.share_info:
 343             raise ValueError('share difficulty invalid')
 344
 345         if bitcoin_data.check_merkle_branch(gentx, 0, self.merkle_branch) != self.header['merkle_root']:
 346             raise ValueError('''gentx doesn't match header via merkle_branch''')
 347
 348     def as_block(self, tracker, net):
 349         if self.other_txs is None:
 350             raise ValueError('share does not contain all txs')
 351
 352         share_info, gentx = new_generate_transaction(tracker, self.share_info['new_share_data'], self.header['target'], self.share_info['timestamp'], net)
 353         assert share_info == self.share_info
 354
 355         return dict(header=self.header, txs=[gentx] + self.other_txs)
 356
 357 def get_pool_attempts_per_second(tracker, previous_share_hash, net, dist=None):
 358     if dist is None:
 359         dist = net.TARGET_LOOKBEHIND
 360     near = tracker.shares[previous_share_hash]
 361     far = tracker.shares[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 362     attempts = tracker.get_work(near.hash) - tracker.get_work(far.hash)
 363     time = near.timestamp - far.timestamp
 364     if time == 0:
 365         time = 1
 366     return attempts//time
 367
 368 def generate_transaction(tracker, previous_share_hash, new_script, subsidy, nonce, block_target, net):
 369     donation = int(0.005*65535 + 0.5)
 370
 371     height, last = tracker.get_height_and_last(previous_share_hash)
 372     assert height >= net.CHAIN_LENGTH or last is None
 373     if height < net.TARGET_LOOKBEHIND:
 374         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 375     else:
 376         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 377         previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 378         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 379         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 380         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 381         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 382
 383     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 384     max_att = net.SPREAD * attempts_to_block
 385
 386     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
 387     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))
 388     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 389     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
 390     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 391
 392     total_weight -= donation_weight # ignore donation
 393
 394     if net.SCRIPT:
 395         amounts = dict((script, subsidy*(396*weight)//(400*total_weight)) for (script, weight) in weights.iteritems())
 396         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 397         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy*2//400
 398         amounts[net.SCRIPT] = amounts.get(net.SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 399     else:
 400         amounts = dict((script, subsidy*(398*weight)//(400*total_weight)) for (script, weight) in weights.iteritems())
 401         amounts[new_script] = amounts.get(new_script, 0) + subsidy*2//400
 402         amounts[new_script] = amounts.get(new_script, 0) + subsidy - sum(amounts.itervalues()) # collect any extra
 403
 404     if sum(amounts.itervalues()) != subsidy:
 405         raise ValueError()
 406     if any(x < 0 for x in amounts.itervalues()):
 407         raise ValueError()
 408
 409     pre_dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 410     pre_dests = pre_dests[-4000:] # block length limit, unlikely to ever be hit
 411
 412     dests = sorted(pre_dests, key=lambda script: (script == new_script, script))
 413     assert dests[-1] == new_script
 414
 415     share_data = dict(
 416         previous_share_hash=previous_share_hash,
 417         nonce=nonce,
 418         target=target,
 419     )
 420
 421     share_info = dict(
 422         share_data=share_data,
 423         new_script=new_script,
 424         subsidy=subsidy,
 425     )
 426
 427     return share_info, dict(
 428         version=1,
 429         tx_ins=[dict(
 430             previous_output=None,
 431             sequence=None,
 432             script=coinbase_type.pack(dict(
 433                 identifier=net.IDENTIFIER,
 434                 share_data=share_data,
 435             )),
 436         )],
 437         tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 438         lock_time=0,
 439     )
 440
 441 def new_generate_transaction(tracker, new_share_data, block_target, desired_timestamp, net):
 442     previous_share_hash = new_share_data['previous_share_hash']
 443     new_script = new_share_data['new_script']
 444     subsidy = new_share_data['subsidy']
 445     donation = new_share_data['donation']
 446     assert 0 <= donation <= 65535
 447
 448     if len(new_share_data['coinbase']) > 100:
 449         raise ValueError('coinbase too long!')
 450
 451     previous_share = tracker.shares[previous_share_hash] if previous_share_hash is not None else None
 452
 453     height, last = tracker.get_height_and_last(previous_share_hash)
 454     assert height >= net.CHAIN_LENGTH or last is None
 455     if height < net.TARGET_LOOKBEHIND:
 456         target = bitcoin_data.FloatingInteger.from_target_upper_bound(net.MAX_TARGET)
 457     else:
 458         attempts_per_second = get_pool_attempts_per_second(tracker, previous_share_hash, net)
 459         pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1
 460         pre_target2 = math.clip(pre_target, (previous_share.target*9//10, previous_share.target*11//10))
 461         pre_target3 = math.clip(pre_target2, (0, net.MAX_TARGET))
 462         target = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 463
 464     attempts_to_block = bitcoin_data.target_to_average_attempts(block_target)
 465     max_att = net.SPREAD * attempts_to_block
 466
 467     this_att = min(bitcoin_data.target_to_average_attempts(target), max_att)
 468     other_weights, other_total_weight, other_donation_weight = tracker.get_cumulative_weights(previous_share_hash, min(height, getattr(net, 'CHAIN_LENGTH2', net.CHAIN_LENGTH)), 65535*max(0, max_att - this_att))
 469     assert other_total_weight == sum(other_weights.itervalues()) + other_donation_weight, (other_total_weight, sum(other_weights.itervalues()) + other_donation_weight)
 470     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
 471     assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 472
 473     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 474
 475     # 1 satoshi is always donated so that a list of p2pool generated blocks can be easily found by looking at the donation address
 476     amounts = dict((script, (subsidy-1)*(199*weight)//(200*total_weight)) for (script, weight) in weights.iteritems())
 477     amounts[new_script] = amounts.get(new_script, 0) + (subsidy-1)//200
 478     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + (subsidy-1)*(199*donation_weight)//(200*total_weight)
 479     amounts[SCRIPT] = amounts.get(SCRIPT, 0) + subsidy - sum(amounts.itervalues()) # collect any extra satoshis :P
 480
 481     if sum(amounts.itervalues()) != subsidy:
 482         raise ValueError()
 483     if any(x < 0 for x in amounts.itervalues()):
 484         raise ValueError()
 485
 486     dests = sorted(amounts.iterkeys(), key=lambda script: (amounts[script], script))
 487     dests = dests[-4000:] # block length limit, unlikely to ever be hit
 488
 489     share_info = dict(
 490         new_share_data=new_share_data,
 491         target=target,
 492         timestamp=math.clip(desired_timestamp, (previous_share.timestamp - 60, previous_share.timestamp + 60)) if previous_share is not None else desired_timestamp,
 493     )
 494
 495     return share_info, dict(
 496         version=1,
 497         tx_ins=[dict(
 498             previous_output=None,
 499             sequence=None,
 500             script=new_share_data['coinbase'].ljust(2, '\x00'),
 501         )],
 502         tx_outs=[dict(value=0, script='\x20' + bitcoin_data.HashType().pack(new_share_info_type.hash256(share_info)))] + [dict(value=amounts[script], script=script) for script in dests if amounts[script]],
 503         lock_time=0,
 504     )
 505
 506
 507 class OkayTracker(bitcoin_data.Tracker):
 508     def __init__(self, net):
 509         bitcoin_data.Tracker.__init__(self)
 510         self.net = net
 511         self.verified = bitcoin_data.Tracker()
 512         self.verified.get_nth_parent_hash = self.get_nth_parent_hash # self is a superset of self.verified
 513
 514         self.get_cumulative_weights = skiplists.WeightsSkipList(self)
 515
 516     def add(self, share, known_verified=False):
 517         bitcoin_data.Tracker.add(self, share)
 518         if known_verified:
 519             self.verified.add(share)
 520
 521     def attempt_verify(self, share, now):
 522         if share.hash in self.verified.shares:
 523             return True
 524         height, last = self.get_height_and_last(share.hash)
 525         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 526             raise AssertionError()
 527         try:
 528             share.check(self, now, self.net)
 529         except:
 530             log.err(None, 'Share check failed:')
 531             return False
 532         else:
 533             self.verified.add(share)
 534             return True
 535
 536     def think(self, ht, previous_block, now):
 537         desired = set()
 538
 539         # O(len(self.heads))
 540         #   make 'unverified heads' set?
 541         # for each overall head, attempt verification
 542         # if it fails, attempt on parent, and repeat
 543         # if no successful verification because of lack of parents, request parent
 544         bads = set()
 545         for head in set(self.heads) - set(self.verified.heads):
 546             head_height, last = self.get_height_and_last(head)
 547
 548             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))):
 549                 if self.attempt_verify(share, now):
 550                     break
 551                 if share.hash in self.heads:
 552                     bads.add(share.hash)
 553             else:
 554                 if last is not None:
 555                     desired.add((self.shares[random.choice(list(self.reverse_shares[last]))].peer, last))
 556         for bad in bads:
 557             assert bad not in self.verified.shares
 558             assert bad in self.heads
 559             if p2pool.DEBUG:
 560                 print "BAD", bad
 561             self.remove(bad)
 562
 563         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 564         for head in list(self.verified.heads):
 565             head_height, last_hash = self.verified.get_height_and_last(head)
 566             last_height, last_last_hash = self.get_height_and_last(last_hash)
 567             # XXX review boundary conditions
 568             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 569             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 570             get = min(want, can)
 571             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 572             for share in itertools.islice(self.get_chain_known(last_hash), get):
 573                 if not self.attempt_verify(share, now):
 574                     break
 575             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 576                 desired.add((self.verified.shares[random.choice(list(self.verified.reverse_shares[last_hash]))].peer, last_last_hash))
 577
 578         # decide best tree
 579         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
 580         # decide best verified head
 581         scores = sorted(self.verified.tails.get(best_tail, []), key=lambda h: (
 582             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 583             #self.verified.shares[h].peer is None,
 584             ht.get_min_height(self.verified.shares[h].previous_block),
 585             -self.verified.shares[h].time_seen
 586         ))
 587
 588
 589         if p2pool.DEBUG:
 590             print len(self.verified.tails), "chain tails and", len(self.verified.tails.get(best_tail, [])), 'chain heads. Top 10 heads:'
 591             if len(scores) > 10:
 592                 print '    ...'
 593             for h in scores[-10:]:
 594                 print '   ', format_hash(h), format_hash(self.verified.shares[h].previous_hash), (
 595                     self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 596                     self.verified.shares[h].peer is None,
 597                     ht.get_min_height(self.verified.shares[h].previous_block),
 598                     -self.verified.shares[h].time_seen
 599                 )
 600
 601         # eat away at heads
 602         if scores:
 603             for i in xrange(1000):
 604                 to_remove = set()
 605                 for share_hash, tail in self.heads.iteritems():
 606                     if share_hash in scores[-5:]:
 607                         #print 1
 608                         continue
 609                     if self.shares[share_hash].time_seen > time.time() - 300:
 610                         #print 2
 611                         continue
 612                     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
 613                         #print 3
 614                         continue
 615                     to_remove.add(share_hash)
 616                 if not to_remove:
 617                     break
 618                 for share_hash in to_remove:
 619                     self.remove(share_hash)
 620                     if share_hash in self.verified.shares:
 621                         self.verified.remove(share_hash)
 622                 #print "_________", to_remove
 623
 624         # drop tails
 625         for i in xrange(1000):
 626             to_remove = set()
 627             for tail, heads in self.tails.iteritems():
 628                 if min(self.get_height(head) for head in heads) < 2*self.net.CHAIN_LENGTH + 10:
 629                     continue
 630                 for aftertail in self.reverse_shares.get(tail, set()):
 631                     if len(self.reverse_shares[self.shares[aftertail].previous_hash]) > 1: # XXX
 632                         print "raw"
 633                         continue
 634                     to_remove.add(aftertail)
 635             if not to_remove:
 636                 break
 637             # if removed from this, it must be removed from verified
 638             #start = time.time()
 639             for aftertail in to_remove:
 640                 if self.shares[aftertail].previous_hash not in self.tails:
 641                     print "erk", aftertail, self.shares[aftertail].previous_hash
 642                     continue
 643                 self.remove(aftertail)
 644                 if aftertail in self.verified.shares:
 645                     self.verified.remove(aftertail)
 646             #end = time.time()
 647             #print "removed! %i %f" % (len(to_remove), (end - start)/len(to_remove))
 648
 649         best = scores[-1] if scores else None
 650
 651         if best is not None:
 652             best_share = self.verified.shares[best]
 653             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:
 654                 if p2pool.DEBUG:
 655                     print 'Stale detected! %x < %x' % (best_share.header['previous_block'], previous_block)
 656                 best = best_share.previous_hash
 657
 658         return best, desired
 659
 660     @memoize.memoize_with_backing(expiring_dict.ExpiringDict(5, get_touches=False))
 661     def score(self, share_hash, ht):
 662         head_height, last = self.verified.get_height_and_last(share_hash)
 663         score2 = 0
 664         attempts = 0
 665         max_height = 0
 666         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
 667         for share in reversed(list(itertools.islice(self.verified.get_chain_known(share2_hash), self.net.CHAIN_LENGTH))):
 668             max_height = max(max_height, ht.get_min_height(share.header['previous_block']))
 669             attempts += bitcoin_data.target_to_average_attempts(share.target)
 670             this_score = attempts//(ht.get_highest_height() - max_height + 1)
 671             if this_score > score2:
 672                 score2 = this_score
 673         return min(head_height, self.net.CHAIN_LENGTH), score2
 674
 675 def format_hash(x):
 676     if x is None:
 677         return 'xxxxxxxx'
 678     return '%08x' % (x % 2**32)
 679
 680 class ShareStore(object):
 681     def __init__(self, prefix, net):
 682         self.filename = prefix
 683         self.dirname = os.path.dirname(os.path.abspath(prefix))
 684         self.filename = os.path.basename(os.path.abspath(prefix))
 685         self.net = net
 686         self.known = None # will be filename -> set of share hashes, set of verified hashes
 687
 688     def get_shares(self):
 689         if self.known is not None:
 690             raise AssertionError()
 691         known = {}
 692         filenames, next = self.get_filenames_and_next()
 693         for filename in filenames:
 694             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 695             with open(filename, 'rb') as f:
 696                 for line in f:
 697                     try:
 698                         type_id_str, data_hex = line.strip().split(' ')
 699                         type_id = int(type_id_str)
 700                         if type_id == 0:
 701                             share = Share.from_share1a(share1a_type.unpack(data_hex.decode('hex')), self.net)
 702                             yield 'share', share
 703                             share_hashes.add(share.hash)
 704                         elif type_id == 1:
 705                             share = Share.from_share1b(share1b_type.unpack(data_hex.decode('hex')), self.net)
 706                             yield 'share', share
 707                             share_hashes.add(share.hash)
 708                         elif type_id == 2:
 709                             verified_hash = int(data_hex, 16)
 710                             yield 'verified_hash', verified_hash
 711                             verified_hashes.add(verified_hash)
 712                         elif type_id == 5:
 713                             share = NewShare.from_share(new_share_type.unpack(data_hex.decode('hex')), self.net)
 714                             yield 'share', share
 715                             share_hashes.add(share.hash)
 716                         else:
 717                             raise NotImplementedError("share type %i" % (type_id,))
 718                     except Exception:
 719                         log.err(None, "Error while reading saved shares, continuing where left off:")
 720         self.known = known
 721
 722     def _add_line(self, line):
 723         filenames, next = self.get_filenames_and_next()
 724         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 725             filename = filenames[-1]
 726         else:
 727             filename = next
 728
 729         with open(filename, 'ab') as f:
 730             f.write(line + '\n')
 731
 732         return filename
 733
 734     def add_share(self, share):
 735         if isinstance(share, NewShare):
 736             type_id, data = 5, new_share_type.pack(share.as_share())
 737         elif share.pow_hash <= share.header['target']:
 738             type_id, data = 1, share1b_type.pack(share.as_share1b())
 739         else:
 740             type_id, data = 0, share1a_type.pack(share.as_share1a())
 741         filename = self._add_line("%i %s" % (type_id, data.encode('hex')))
 742         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 743         share_hashes.add(share.hash)
 744
 745     def add_verified_hash(self, share_hash):
 746         filename = self._add_line("%i %x" % (2, share_hash))
 747         share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 748         verified_hashes.add(share_hash)
 749
 750     def get_filenames_and_next(self):
 751         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())
 752         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)))
 753
 754     def forget_share(self, share_hash):
 755         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 756             if share_hash in share_hashes:
 757                 share_hashes.remove(share_hash)
 758         self.check_remove()
 759
 760     def forget_verified_share(self, share_hash):
 761         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 762             if share_hash in verified_hashes:
 763                 verified_hashes.remove(share_hash)
 764         self.check_remove()
 765
 766     def check_remove(self):
 767         to_remove = set()
 768         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 769             #print filename, len(share_hashes) + len(verified_hashes)
 770             if not share_hashes and not verified_hashes:
 771                 to_remove.add(filename)
 772         for filename in to_remove:
 773             self.known.pop(filename)
 774             os.remove(filename)
 775             print "REMOVED", filename
 776
 777 class BitcoinMainnet(networks.BitcoinMainnet):
 778     SHARE_PERIOD = 10 # seconds
 779     CHAIN_LENGTH = 24*60*60//5 # shares
 780     CHAIN_LENGTH2 = 24*60*60//10//2 # shares
 781     TARGET_LOOKBEHIND = 200 # shares
 782     SPREAD = 3 # blocks
 783     SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
 784     IDENTIFIER = 'fc70035c7a81bc6f'.decode('hex')
 785     PREFIX = '2472ef181efcd37b'.decode('hex')
 786     NAME = 'bitcoin'
 787     P2P_PORT = 9333
 788     MAX_TARGET = 2**256//2**32 - 1
 789     PERSIST = True
 790     WORKER_PORT = 9332
 791
 792 class BitcoinTestnet(networks.BitcoinTestnet):
 793     SHARE_PERIOD = 1 # seconds
 794     CHAIN_LENGTH = 24*60*60//5 # shares
 795     CHAIN_LENGTH2 = 24*60*60//10//2 # shares
 796     TARGET_LOOKBEHIND = 200 # shares
 797     SPREAD = 3 # blocks
 798     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 799     IDENTIFIER = '5fc2be2d4f0d6bfb'.decode('hex')
 800     PREFIX = '3f6057a15036f441'.decode('hex')
 801     NAME = 'bitcoin_testnet'
 802     P2P_PORT = 19333
 803     MAX_TARGET = 2**256//2**32 - 1
 804     PERSIST = False
 805     WORKER_PORT = 19332
 806
 807 class NamecoinMainnet(networks.NamecoinMainnet):
 808     SHARE_PERIOD = 10 # seconds
 809     CHAIN_LENGTH = 24*60*60//10 # shares
 810     TARGET_LOOKBEHIND = 3600//10 # shares
 811     SPREAD = 3 # blocks
 812     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 813     IDENTIFIER = 'd5b1192062c4c454'.decode('hex')
 814     PREFIX = 'b56f3d0fb24fc982'.decode('hex')
 815     NAME = 'namecoin'
 816     P2P_PORT = 9334
 817     MAX_TARGET = 2**256//2**32 - 1
 818     PERSIST = True
 819     WORKER_PORT = 9331
 820
 821 class NamecoinTestnet(networks.NamecoinTestnet):
 822     SHARE_PERIOD = 1 # seconds
 823     CHAIN_LENGTH = 24*60*60//5 # shares
 824     TARGET_LOOKBEHIND = 200 # shares
 825     SPREAD = 3 # blocks
 826     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 827     IDENTIFIER = '8dd303d014a01a60'.decode('hex')
 828     PREFIX = '4d6581d24f51acbf'.decode('hex')
 829     NAME = 'namecoin_testnet'
 830     P2P_PORT = 19334
 831     MAX_TARGET = 2**256//2**20 - 1
 832     PERSIST = False
 833     WORKER_PORT = 19331
 834
 835 class IxcoinMainnet(networks.IxcoinMainnet):
 836     SHARE_PERIOD = 10 # seconds
 837     CHAIN_LENGTH = 24*60*60//10 # shares
 838     TARGET_LOOKBEHIND = 3600//10 # shares
 839     SPREAD = 3 # blocks
 840     SCRIPT = '41043da5beb73f8f18cede1a41b0ed953123f1342b8e0216ab5bf71ed3e024201b4017f472bddb6041f17978d89ed8f8ed84f9e726b0bca80cacf96347c7153e8df0ac'.decode('hex')
 841     IDENTIFIER = '27b564116e2a2666'.decode('hex')
 842     PREFIX = '9dd6c4a619401f2f'.decode('hex')
 843     NAME = 'ixcoin'
 844     P2P_PORT = 9335
 845     MAX_TARGET = 2**256//2**32 - 1
 846     PERSIST = True
 847     WORKER_PORT = 9330
 848
 849 class IxcoinTestnet(networks.IxcoinTestnet):
 850     SHARE_PERIOD = 1 # seconds
 851     CHAIN_LENGTH = 24*60*60//5 # shares
 852     TARGET_LOOKBEHIND = 200 # shares
 853     SPREAD = 3 # blocks
 854     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 855     IDENTIFIER = '7430cbeb01249e44'.decode('hex')
 856     PREFIX = '7cfffda946709c1f'.decode('hex')
 857     NAME = 'ixcoin_testnet'
 858     P2P_PORT = 19335
 859     MAX_TARGET = 2**256//2**20 - 1
 860     PERSIST = False
 861     WORKER_PORT = 19330
 862
 863 class I0coinMainnet(networks.I0coinMainnet):
 864     SHARE_PERIOD = 10 # seconds
 865     CHAIN_LENGTH = 24*60*60//10 # shares
 866     TARGET_LOOKBEHIND = 3600//10 # shares
 867     SPREAD = 3 # blocks
 868     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 869     IDENTIFIER = 'b32e3f10c2ff221b'.decode('hex')
 870     PREFIX = '6155537ed977a3b5'.decode('hex')
 871     NAME = 'i0coin'
 872     P2P_PORT = 9336
 873     MAX_TARGET = 2**256//2**32 - 1
 874     PERSIST = False
 875     WORKER_PORT = 9329
 876
 877 class I0coinTestnet(networks.I0coinTestnet):
 878     SHARE_PERIOD = 1 # seconds
 879     CHAIN_LENGTH = 24*60*60//5 # shares
 880     TARGET_LOOKBEHIND = 200 # shares
 881     SPREAD = 3 # blocks
 882     SCRIPT = '410403ad3dee8ab3d8a9ce5dd2abfbe7364ccd9413df1d279bf1a207849310465b0956e5904b1155ecd17574778f9949589ebfd4fb33ce837c241474a225cf08d85dac'.decode('hex')
 883     IDENTIFIER = '7712c1a8181b5f2e'.decode('hex')
 884     PREFIX = '792d2e7d770fbe68'.decode('hex')
 885     NAME = 'i0coin_testnet'
 886     P2P_PORT = 19336
 887     MAX_TARGET = 2**256//2**20 - 1
 888     PERSIST = False
 889     WORKER_PORT = 19329
 890
 891 class SolidcoinMainnet(networks.SolidcoinMainnet):
 892     SHARE_PERIOD = 10
 893     CHAIN_LENGTH = 24*60*60//10 # shares
 894     TARGET_LOOKBEHIND = 3600//10 # shares
 895     SPREAD = 3 # blocks
 896     SCRIPT = bitcoin_data.pubkey_hash_to_script2(bitcoin_data.address_to_pubkey_hash('sMKZ1yxHETxPYKh4Z2anWnwZDJZU7ztroy', networks.SolidcoinMainnet))
 897     IDENTIFIER = '9cc9c421cca258cd'.decode('hex')
 898     PREFIX = 'c059125b8070f00a'.decode('hex')
 899     NAME = 'solidcoin'
 900     P2P_PORT = 9337
 901     MAX_TARGET = 2**256//2**32 - 1
 902     PERSIST = True
 903     WORKER_PORT = 9328
 904
 905 class LitecoinMainnet(networks.LitecoinMainnet):
 906     SHARE_PERIOD = 10 # seconds
 907     CHAIN_LENGTH = 24*60*60//5 # shares
 908     CHAIN_LENGTH2 = 24*60*60//10//2 # shares
 909     TARGET_LOOKBEHIND = 200 # shares
 910     SPREAD = 12 # blocks
 911     SCRIPT = None # no fee
 912     IDENTIFIER = 'e037d5b8c6923410'.decode('hex')
 913     PREFIX = '7208c1a53ef629b0'.decode('hex')
 914     NAME = 'litecoin'
 915     P2P_PORT = 9338
 916     MAX_TARGET = 2**256//2**20 - 1
 917     PERSIST = True
 918     WORKER_PORT = 9327
 919
 920 class LitecoinTestnet(networks.LitecoinTestnet):
 921     SHARE_PERIOD = 1 # seconds
 922     CHAIN_LENGTH = 24*60*60//5 # shares
 923     TARGET_LOOKBEHIND = 200 # shares
 924     SPREAD = 12 # blocks
 925     SCRIPT = None # no fee
 926     IDENTIFIER = 'cca5e24ec6408b1e'.decode('hex')
 927     PREFIX = 'ad9614f6466a39cf'.decode('hex')
 928     NAME = 'litecoin_testnet'
 929     P2P_PORT = 19338
 930     MAX_TARGET = 2**256//2**17 - 1
 931     PERSIST = False
 932     WORKER_PORT = 19327
 933
 934 nets = dict((net.NAME, net) for net in set([BitcoinMainnet, BitcoinTestnet, NamecoinMainnet, NamecoinTestnet, IxcoinMainnet, IxcoinTestnet, I0coinMainnet, I0coinTestnet, SolidcoinMainnet, LitecoinMainnet, LitecoinTestnet]))