p2pool/data.py

   1 from __future__ import division
   2
   3 import hashlib
   4 import os
   5 import random
   6 import sys
   7 import time
   8
   9 from twisted.python import log
  10
  11 import p2pool
  12 from p2pool.bitcoin import data as bitcoin_data, script, sha256
  13 from p2pool.util import math, forest, pack
  14
  15 # hashlink
  16
  17 hash_link_type = pack.ComposedType([
  18     ('state', pack.FixedStrType(32)),
  19     ('extra_data', pack.FixedStrType(0)), # bit of a hack, but since the donation script is at the end, const_ending is long enough to always make this empty
  20     ('length', pack.VarIntType()),
  21 ])
  22
  23 def prefix_to_hash_link(prefix, const_ending=''):
  24     assert prefix.endswith(const_ending), (prefix, const_ending)
  25     x = sha256.sha256(prefix)
  26     return dict(state=x.state, extra_data=x.buf[:max(0, len(x.buf)-len(const_ending))], length=x.length//8)
  27
  28 def check_hash_link(hash_link, data, const_ending=''):
  29     extra_length = hash_link['length'] % (512//8)
  30     assert len(hash_link['extra_data']) == max(0, extra_length - len(const_ending))
  31     extra = (hash_link['extra_data'] + const_ending)[len(hash_link['extra_data']) + len(const_ending) - extra_length:]
  32     assert len(extra) == extra_length
  33     return pack.IntType(256).unpack(hashlib.sha256(sha256.sha256(data, (hash_link['state'], extra, 8*hash_link['length'])).digest()).digest())
  34
  35 # shares
  36
  37 share_type = pack.ComposedType([
  38     ('type', pack.VarIntType()),
  39     ('contents', pack.VarStrType()),
  40 ])
  41
  42 def load_share(share, net, peer_addr):
  43     assert peer_addr is None or isinstance(peer_addr, tuple)
  44     if share['type'] < Share.VERSION:
  45         from p2pool import p2p
  46         raise p2p.PeerMisbehavingError('sent an obsolete share')
  47     elif share['type'] == Share.VERSION:
  48         return Share(net, peer_addr, Share.share_type.unpack(share['contents']))
  49     elif share['type'] == NewShare.VERSION:
  50         return NewShare(net, peer_addr, NewShare.share_type.unpack(share['contents']))
  51     else:
  52         raise ValueError('unknown share type: %r' % (share['type'],))
  53
  54 DONATION_SCRIPT = '4104ffd03de44a6e11b9917f3a29f9443283d9871c9d743ef30d5eddcd37094b64d1b3d8090496b53256786bf5c82932ec23c3b74d9f05a6f95a8b5529352656664bac'.decode('hex')
  55
  56 class NewShare(object):
  57     VERSION = 13
  58     VOTING_VERSION = 13
  59     SUCCESSOR = None
  60
  61     small_block_header_type = pack.ComposedType([
  62         ('version', pack.VarIntType()),
  63         ('previous_block', pack.PossiblyNoneType(0, pack.IntType(256))),
  64         ('timestamp', pack.IntType(32)),
  65         ('bits', bitcoin_data.FloatingIntegerType()),
  66         ('nonce', pack.IntType(32)),
  67     ])
  68
  69     share_info_type = pack.ComposedType([
  70         ('share_data', pack.ComposedType([
  71             ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  72             ('coinbase', pack.VarStrType()),
  73             ('nonce', pack.IntType(32)),
  74             ('pubkey_hash', pack.IntType(160)),
  75             ('subsidy', pack.IntType(64)),
  76             ('donation', pack.IntType(16)),
  77             ('stale_info', pack.EnumType(pack.IntType(8), dict((k, {0: None, 253: 'orphan', 254: 'doa'}.get(k, 'unk%i' % (k,))) for k in xrange(256)))),
  78             ('desired_version', pack.VarIntType()),
  79         ])),
  80         ('new_transaction_hashes', pack.ListType(pack.IntType(256))),
  81         ('transaction_hash_refs', pack.ListType(pack.VarIntType(), 2)), # pairs of share_count, tx_count
  82         ('far_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
  83         ('max_bits', bitcoin_data.FloatingIntegerType()),
  84         ('bits', bitcoin_data.FloatingIntegerType()),
  85         ('timestamp', pack.IntType(32)),
  86     ])
  87
  88     share_type = pack.ComposedType([
  89         ('min_header', small_block_header_type),
  90         ('share_info', share_info_type),
  91         ('ref_merkle_link', pack.ComposedType([
  92             ('branch', pack.ListType(pack.IntType(256))),
  93             ('index', pack.IntType(0)),
  94         ])),
  95         ('last_txout_nonce', pack.IntType(64)),
  96         ('hash_link', hash_link_type),
  97         ('merkle_link', pack.ComposedType([
  98             ('branch', pack.ListType(pack.IntType(256))),
  99             ('index', pack.IntType(0)), # it will always be 0
 100         ])),
 101     ])
 102
 103     ref_type = pack.ComposedType([
 104         ('identifier', pack.FixedStrType(64//8)),
 105         ('share_info', share_info_type),
 106     ])
 107
 108     gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x6a\x28' + pack.IntType(256).pack(0) + pack.IntType(64).pack(0))[:3]
 109
 110     @classmethod
 111     def generate_transaction(cls, tracker, share_data, block_target, desired_timestamp, desired_target, ref_merkle_link, desired_other_transaction_hashes_and_fees, net, known_txs=None, last_txout_nonce=0, base_subsidy=None):
 112         previous_share = tracker.items[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 113
 114         height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 115         assert height >= net.REAL_CHAIN_LENGTH or last is None
 116         if height < net.TARGET_LOOKBEHIND:
 117             pre_target3 = net.MAX_TARGET
 118         else:
 119             attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 120             pre_target = 2**256//(net.NEW_SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 121             pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 122             pre_target3 = math.clip(pre_target2, (net.MIN_TARGET, net.MAX_TARGET))
 123         max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 124         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 125
 126         new_transaction_hashes = []
 127         new_transaction_size = 0
 128         transaction_hash_refs = []
 129         other_transaction_hashes = []
 130
 131         past_shares = list(tracker.get_chain(share_data['previous_share_hash'], min(height, 100)))
 132         tx_hash_to_this = {}
 133         for i, share in enumerate(past_shares):
 134             for j, tx_hash in enumerate(share.new_transaction_hashes):
 135                 if tx_hash not in tx_hash_to_this:
 136                     tx_hash_to_this[tx_hash] = [1+i, j] # share_count, tx_count
 137         for tx_hash, fee in desired_other_transaction_hashes_and_fees:
 138             if tx_hash in tx_hash_to_this:
 139                 this = tx_hash_to_this[tx_hash]
 140             else:
 141                 if known_txs is not None:
 142                     this_size = bitcoin_data.tx_type.packed_size(known_txs[tx_hash])
 143                     if new_transaction_size + this_size > 50000: # only allow 50 kB of new txns/share
 144                         break
 145                     new_transaction_size += this_size
 146                 new_transaction_hashes.append(tx_hash)
 147                 this = [0, len(new_transaction_hashes)-1]
 148             transaction_hash_refs.extend(this)
 149             other_transaction_hashes.append(tx_hash)
 150
 151         included_transactions = set(other_transaction_hashes)
 152         removed_fees = [fee for tx_hash, fee in desired_other_transaction_hashes_and_fees if tx_hash not in included_transactions]
 153         definite_fees = sum(0 if fee is None else fee for tx_hash, fee in desired_other_transaction_hashes_and_fees if tx_hash in included_transactions)
 154         if None not in removed_fees:
 155             share_data = dict(share_data, subsidy=share_data['subsidy'] - sum(removed_fees))
 156         else:
 157             assert base_subsidy is not None
 158             share_data = dict(share_data, subsidy=base_subsidy + definite_fees)
 159
 160         weights, total_weight, donation_weight = tracker.get_cumulative_weights(previous_share.share_data['previous_share_hash'] if previous_share is not None else None,
 161             min(height, net.REAL_CHAIN_LENGTH-1),
 162             65535*net.NEW_SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 163         )
 164         assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 165
 166         amounts = dict((script, share_data['subsidy']*(199*weight)//(200*total_weight)) for script, weight in weights.iteritems()) # 99.5% goes according to weights prior to this share
 167         this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
 168         amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
 169         amounts[DONATION_SCRIPT] = amounts.get(DONATION_SCRIPT, 0) + share_data['subsidy'] - sum(amounts.itervalues()) # all that's left over is the donation weight and some extra satoshis due to rounding
 170
 171         if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
 172             raise ValueError()
 173
 174         dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
 175
 176         share_info = dict(
 177             share_data=share_data,
 178             far_share_hash=None if last is None and height < 99 else tracker.get_nth_parent_hash(share_data['previous_share_hash'], 99),
 179             max_bits=max_bits,
 180             bits=bits,
 181             timestamp=math.clip(desired_timestamp, (
 182                 (previous_share.timestamp + net.NEW_SHARE_PERIOD) - (net.NEW_SHARE_PERIOD - 1), # = previous_share.timestamp + 1
 183                 (previous_share.timestamp + net.NEW_SHARE_PERIOD) + (net.NEW_SHARE_PERIOD - 1),
 184             )) if previous_share is not None else desired_timestamp,
 185             new_transaction_hashes=new_transaction_hashes,
 186             transaction_hash_refs=transaction_hash_refs,
 187         )
 188
 189         gentx = dict(
 190             version=1,
 191             tx_ins=[dict(
 192                 previous_output=None,
 193                 sequence=None,
 194                 script=share_data['coinbase'],
 195             )],
 196             tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script] or script == DONATION_SCRIPT] + [dict(
 197                 value=0,
 198                 script='\x6a\x28' + cls.get_ref_hash(net, share_info, ref_merkle_link) + pack.IntType(64).pack(last_txout_nonce),
 199             )],
 200             lock_time=0,
 201         )
 202
 203         def get_share(header, last_txout_nonce=last_txout_nonce):
 204             min_header = dict(header); del min_header['merkle_root']
 205             share = cls(net, None, dict(
 206                 min_header=min_header,
 207                 share_info=share_info,
 208                 ref_merkle_link=dict(branch=[], index=0),
 209                 last_txout_nonce=last_txout_nonce*2**32,
 210                 hash_link=prefix_to_hash_link(bitcoin_data.tx_type.pack(gentx)[:-32-8-4], cls.gentx_before_refhash),
 211                 merkle_link=bitcoin_data.calculate_merkle_link([None] + other_transaction_hashes, 0),
 212             ))
 213             assert share.header == header # checks merkle_root
 214             return share
 215
 216         return share_info, gentx, other_transaction_hashes, get_share
 217
 218     @classmethod
 219     def get_ref_hash(cls, net, share_info, ref_merkle_link):
 220         return pack.IntType(256).pack(bitcoin_data.check_merkle_link(bitcoin_data.hash256(cls.ref_type.pack(dict(
 221             identifier=net.IDENTIFIER,
 222             share_info=share_info,
 223         ))), ref_merkle_link))
 224
 225     __slots__ = 'net peer_addr contents min_header share_info hash_link merkle_link hash share_data max_target target timestamp previous_hash new_script desired_version gentx_hash header pow_hash header_hash new_transaction_hashes time_seen'.split(' ')
 226
 227     def __init__(self, net, peer_addr, contents):
 228         self.net = net
 229         self.peer_addr = peer_addr
 230         self.contents = contents
 231
 232         self.min_header = contents['min_header']
 233         self.share_info = contents['share_info']
 234         self.hash_link = contents['hash_link']
 235         self.merkle_link = contents['merkle_link']
 236
 237         if not (2 <= len(self.share_info['share_data']['coinbase']) <= 100):
 238             raise ValueError('''bad coinbase size! %i bytes''' % (len(self.share_info['share_data']['coinbase']),))
 239
 240         if len(self.merkle_link['branch']) > 16:
 241             raise ValueError('merkle branch too long!')
 242
 243         assert not self.hash_link['extra_data'], repr(self.hash_link['extra_data'])
 244
 245         self.share_data = self.share_info['share_data']
 246         self.max_target = self.share_info['max_bits'].target
 247         self.target = self.share_info['bits'].target
 248         self.timestamp = self.share_info['timestamp']
 249         self.previous_hash = self.share_data['previous_share_hash']
 250         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 251         self.desired_version = self.share_data['desired_version']
 252
 253         n = set()
 254         for share_count, tx_count in self.iter_transaction_hash_refs():
 255             assert share_count < 110
 256             if share_count == 0:
 257                 n.add(tx_count)
 258         assert n == set(range(len(self.share_info['new_transaction_hashes'])))
 259
 260         self.gentx_hash = check_hash_link(
 261             self.hash_link,
 262             self.get_ref_hash(net, self.share_info, contents['ref_merkle_link']) + pack.IntType(64).pack(self.contents['last_txout_nonce']) + pack.IntType(32).pack(0),
 263             self.gentx_before_refhash,
 264         )
 265         merkle_root = bitcoin_data.check_merkle_link(self.gentx_hash, self.merkle_link)
 266         self.header = dict(self.min_header, merkle_root=merkle_root)
 267         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 268         self.hash = self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 269
 270         if self.target > net.MAX_TARGET:
 271             from p2pool import p2p
 272             raise p2p.PeerMisbehavingError('share target invalid')
 273
 274         if self.pow_hash > self.target:
 275             from p2pool import p2p
 276             raise p2p.PeerMisbehavingError('share PoW invalid')
 277
 278         self.new_transaction_hashes = self.share_info['new_transaction_hashes']
 279
 280         # XXX eww
 281         self.time_seen = time.time()
 282
 283     def __repr__(self):
 284         return 'Share' + repr((self.net, self.peer_addr, self.contents))
 285
 286     def as_share(self):
 287         return dict(type=self.VERSION, contents=self.share_type.pack(self.contents))
 288
 289     def iter_transaction_hash_refs(self):
 290         return zip(self.share_info['transaction_hash_refs'][::2], self.share_info['transaction_hash_refs'][1::2])
 291
 292     def check(self, tracker):
 293         from p2pool import p2p
 294         if self.share_data['previous_share_hash'] is not None:
 295             previous_share = tracker.items[self.share_data['previous_share_hash']]
 296             if type(self) is type(previous_share):
 297                 pass
 298             elif type(self) is type(previous_share).SUCCESSOR:
 299                 if tracker.get_height(previous_share.hash) < self.net.CHAIN_LENGTH:
 300                     from p2pool import p2p
 301                     raise p2p.PeerMisbehavingError('switch without enough history')
 302
 303                 # switch only valid if 85% of hashes in [self.net.CHAIN_LENGTH*9//10, self.net.CHAIN_LENGTH] for new version
 304                 counts = get_desired_version_counts(tracker,
 305                     tracker.get_nth_parent_hash(previous_share.hash, self.net.CHAIN_LENGTH*9//10), self.net.CHAIN_LENGTH//10)
 306                 if counts.get(self.VERSION, 0) < sum(counts.itervalues())*85//100:
 307                     raise p2p.PeerMisbehavingError('switch without enough hash power upgraded')
 308             else:
 309                 raise p2p.PeerMisbehavingError('''%s can't follow %s''' % (type(self).__name__, type(previous_share).__name__))
 310
 311         other_tx_hashes = [tracker.items[tracker.get_nth_parent_hash(self.hash, share_count)].share_info['new_transaction_hashes'][tx_count] for share_count, tx_count in self.iter_transaction_hash_refs()]
 312
 313         share_info, gentx, other_tx_hashes2, get_share = self.generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.contents['ref_merkle_link'], [(h, None) for h in other_tx_hashes], self.net, last_txout_nonce=self.contents['last_txout_nonce'])
 314         assert other_tx_hashes2 == other_tx_hashes
 315         if share_info != self.share_info:
 316             raise ValueError('share_info invalid')
 317         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 318             raise ValueError('''gentx doesn't match hash_link''')
 319
 320         if bitcoin_data.calculate_merkle_link([None] + other_tx_hashes, 0) != self.merkle_link:
 321             raise ValueError('merkle_link and other_tx_hashes do not match')
 322
 323         return gentx # only used by as_block
 324
 325     def get_other_tx_hashes(self, tracker):
 326         parents_needed = max(share_count for share_count, tx_count in self.iter_transaction_hash_refs()) if self.share_info['transaction_hash_refs'] else 0
 327         parents = tracker.get_height(self.hash) - 1
 328         if parents < parents_needed:
 329             return None
 330         last_shares = list(tracker.get_chain(self.hash, parents_needed + 1))
 331         return [last_shares[share_count].share_info['new_transaction_hashes'][tx_count] for share_count, tx_count in self.iter_transaction_hash_refs()]
 332
 333     def _get_other_txs(self, tracker, known_txs):
 334         other_tx_hashes = self.get_other_tx_hashes(tracker)
 335         if other_tx_hashes is None:
 336             return None # not all parents present
 337
 338         if not all(tx_hash in known_txs for tx_hash in other_tx_hashes):
 339             return None # not all txs present
 340
 341         return [known_txs[tx_hash] for tx_hash in other_tx_hashes]
 342
 343     def should_punish_reason(self, previous_block, bits, tracker, known_txs):
 344         if (self.header['previous_block'], self.header['bits']) != (previous_block, bits) and self.header_hash != previous_block and self.peer_addr is not None:
 345             return True, 'Block-stale detected! %x < %x' % (self.header['previous_block'], previous_block)
 346
 347         if self.pow_hash <= self.header['bits'].target:
 348             return -1, 'block solution'
 349
 350         other_txs = self._get_other_txs(tracker, known_txs)
 351         if other_txs is None:
 352             if self.time_seen != 0: # ignore if loaded from ShareStore
 353                 return True, 'not all txs present'
 354         else:
 355             all_txs_size = sum(bitcoin_data.tx_type.packed_size(tx) for tx in other_txs)
 356             if all_txs_size > 1000000:
 357                 return True, 'txs over block size limit'
 358
 359             new_txs_size = sum(bitcoin_data.tx_type.packed_size(known_txs[tx_hash]) for tx_hash in self.share_info['new_transaction_hashes'])
 360             if new_txs_size > 50000:
 361                 return True, 'new txs over limit'
 362
 363         return False, None
 364
 365     def as_block(self, tracker, known_txs):
 366         other_txs = self._get_other_txs(tracker, known_txs)
 367         if other_txs is None:
 368             return None # not all txs present
 369         return dict(header=self.header, txs=[self.check(tracker)] + other_txs)
 370
 371 class Share(object):
 372     VERSION = 9
 373     VOTING_VERSION = 11
 374     SUCCESSOR = NewShare
 375
 376     small_block_header_type = pack.ComposedType([
 377         ('version', pack.VarIntType()),
 378         ('previous_block', pack.PossiblyNoneType(0, pack.IntType(256))),
 379         ('timestamp', pack.IntType(32)),
 380         ('bits', bitcoin_data.FloatingIntegerType()),
 381         ('nonce', pack.IntType(32)),
 382     ])
 383
 384     share_info_type = pack.ComposedType([
 385         ('share_data', pack.ComposedType([
 386             ('previous_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
 387             ('coinbase', pack.VarStrType()),
 388             ('nonce', pack.IntType(32)),
 389             ('pubkey_hash', pack.IntType(160)),
 390             ('subsidy', pack.IntType(64)),
 391             ('donation', pack.IntType(16)),
 392             ('stale_info', pack.EnumType(pack.IntType(8), dict((k, {0: None, 253: 'orphan', 254: 'doa'}.get(k, 'unk%i' % (k,))) for k in xrange(256)))),
 393             ('desired_version', pack.VarIntType()),
 394         ])),
 395         ('new_transaction_hashes', pack.ListType(pack.IntType(256))),
 396         ('transaction_hash_refs', pack.ListType(pack.VarIntType(), 2)), # pairs of share_count, tx_count
 397         ('far_share_hash', pack.PossiblyNoneType(0, pack.IntType(256))),
 398         ('max_bits', bitcoin_data.FloatingIntegerType()),
 399         ('bits', bitcoin_data.FloatingIntegerType()),
 400         ('timestamp', pack.IntType(32)),
 401     ])
 402
 403     share_type = pack.ComposedType([
 404         ('min_header', small_block_header_type),
 405         ('share_info', share_info_type),
 406         ('ref_merkle_link', pack.ComposedType([
 407             ('branch', pack.ListType(pack.IntType(256))),
 408             ('index', pack.IntType(0)),
 409         ])),
 410         ('last_txout_nonce', pack.IntType(32)),
 411         ('hash_link', hash_link_type),
 412         ('merkle_link', pack.ComposedType([
 413             ('branch', pack.ListType(pack.IntType(256))),
 414             ('index', pack.IntType(0)), # it will always be 0
 415         ])),
 416     ])
 417
 418     ref_type = pack.ComposedType([
 419         ('identifier', pack.FixedStrType(64//8)),
 420         ('share_info', share_info_type),
 421     ])
 422
 423     gentx_before_refhash = pack.VarStrType().pack(DONATION_SCRIPT) + pack.IntType(64).pack(0) + pack.VarStrType().pack('\x24' + pack.IntType(256).pack(0) + pack.IntType(32).pack(0))[:2]
 424
 425     @classmethod
 426     def generate_transaction(cls, tracker, share_data, block_target, desired_timestamp, desired_target, ref_merkle_link, desired_other_transaction_hashes_and_fees, net, known_txs=None, last_txout_nonce=0, base_subsidy=None):
 427         previous_share = tracker.items[share_data['previous_share_hash']] if share_data['previous_share_hash'] is not None else None
 428
 429         height, last = tracker.get_height_and_last(share_data['previous_share_hash'])
 430         assert height >= net.REAL_CHAIN_LENGTH or last is None
 431         if height < net.TARGET_LOOKBEHIND:
 432             pre_target3 = net.MAX_TARGET
 433         else:
 434             attempts_per_second = get_pool_attempts_per_second(tracker, share_data['previous_share_hash'], net.TARGET_LOOKBEHIND, min_work=True, integer=True)
 435             pre_target = 2**256//(net.SHARE_PERIOD*attempts_per_second) - 1 if attempts_per_second else 2**256-1
 436             pre_target2 = math.clip(pre_target, (previous_share.max_target*9//10, previous_share.max_target*11//10))
 437             pre_target3 = math.clip(pre_target2, (net.MIN_TARGET, net.MAX_TARGET))
 438         max_bits = bitcoin_data.FloatingInteger.from_target_upper_bound(pre_target3)
 439         bits = bitcoin_data.FloatingInteger.from_target_upper_bound(math.clip(desired_target, (pre_target3//10, pre_target3)))
 440
 441         new_transaction_hashes = []
 442         new_transaction_size = 0
 443         transaction_hash_refs = []
 444         other_transaction_hashes = []
 445
 446         past_shares = list(tracker.get_chain(share_data['previous_share_hash'], min(height, 100)))
 447         tx_hash_to_this = {}
 448         for i, share in enumerate(past_shares):
 449             for j, tx_hash in enumerate(share.new_transaction_hashes):
 450                 if tx_hash not in tx_hash_to_this:
 451                     tx_hash_to_this[tx_hash] = [1+i, j] # share_count, tx_count
 452         for tx_hash, fee in desired_other_transaction_hashes_and_fees:
 453             if tx_hash in tx_hash_to_this:
 454                 this = tx_hash_to_this[tx_hash]
 455             else:
 456                 if known_txs is not None:
 457                     this_size = bitcoin_data.tx_type.packed_size(known_txs[tx_hash])
 458                     if new_transaction_size + this_size > 50000: # only allow 50 kB of new txns/share
 459                         break
 460                     new_transaction_size += this_size
 461                 new_transaction_hashes.append(tx_hash)
 462                 this = [0, len(new_transaction_hashes)-1]
 463             transaction_hash_refs.extend(this)
 464             other_transaction_hashes.append(tx_hash)
 465
 466         included_transactions = set(other_transaction_hashes)
 467         removed_fees = [fee for tx_hash, fee in desired_other_transaction_hashes_and_fees if tx_hash not in included_transactions]
 468         definite_fees = sum(0 if fee is None else fee for tx_hash, fee in desired_other_transaction_hashes_and_fees if tx_hash in included_transactions)
 469         if None not in removed_fees:
 470             share_data = dict(share_data, subsidy=share_data['subsidy'] - sum(removed_fees))
 471         else:
 472             assert base_subsidy is not None
 473             share_data = dict(share_data, subsidy=base_subsidy + definite_fees)
 474
 475         weights, total_weight, donation_weight = tracker.get_cumulative_weights(share_data['previous_share_hash'],
 476             min(height, net.REAL_CHAIN_LENGTH),
 477             65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target),
 478         )
 479         assert total_weight == sum(weights.itervalues()) + donation_weight, (total_weight, sum(weights.itervalues()) + donation_weight)
 480
 481         amounts = dict((script, share_data['subsidy']*(199*weight)//(200*total_weight)) for script, weight in weights.iteritems()) # 99.5% goes according to weights prior to this share
 482         this_script = bitcoin_data.pubkey_hash_to_script2(share_data['pubkey_hash'])
 483         amounts[this_script] = amounts.get(this_script, 0) + share_data['subsidy']//200 # 0.5% goes to block finder
 484         amounts[DONATION_SCRIPT] = amounts.get(DONATION_SCRIPT, 0) + share_data['subsidy'] - sum(amounts.itervalues()) # all that's left over is the donation weight and some extra satoshis due to rounding
 485
 486         if sum(amounts.itervalues()) != share_data['subsidy'] or any(x < 0 for x in amounts.itervalues()):
 487             raise ValueError()
 488
 489         dests = sorted(amounts.iterkeys(), key=lambda script: (script == DONATION_SCRIPT, amounts[script], script))[-4000:] # block length limit, unlikely to ever be hit
 490
 491         share_info = dict(
 492             share_data=share_data,
 493             far_share_hash=None if last is None and height < 99 else tracker.get_nth_parent_hash(share_data['previous_share_hash'], 99),
 494             max_bits=max_bits,
 495             bits=bits,
 496             timestamp=math.clip(desired_timestamp, (
 497                 (previous_share.timestamp + net.SHARE_PERIOD) - (net.SHARE_PERIOD - 1), # = previous_share.timestamp + 1
 498                 (previous_share.timestamp + net.SHARE_PERIOD) + (net.SHARE_PERIOD - 1),
 499             )) if previous_share is not None else desired_timestamp,
 500             new_transaction_hashes=new_transaction_hashes,
 501             transaction_hash_refs=transaction_hash_refs,
 502         )
 503
 504         gentx = dict(
 505             version=1,
 506             tx_ins=[dict(
 507                 previous_output=None,
 508                 sequence=None,
 509                 script=share_data['coinbase'],
 510             )],
 511             tx_outs=[dict(value=amounts[script], script=script) for script in dests if amounts[script] or script == DONATION_SCRIPT] + [dict(
 512                 value=0,
 513                 script='\x24' + cls.get_ref_hash(net, share_info, ref_merkle_link) + pack.IntType(32).pack(last_txout_nonce),
 514             )],
 515             lock_time=0,
 516         )
 517
 518         def get_share(header, last_txout_nonce=last_txout_nonce):
 519             min_header = dict(header); del min_header['merkle_root']
 520             share = cls(net, None, dict(
 521                 min_header=min_header,
 522                 share_info=share_info,
 523                 ref_merkle_link=dict(branch=[], index=0),
 524                 last_txout_nonce=last_txout_nonce,
 525                 hash_link=prefix_to_hash_link(bitcoin_data.tx_type.pack(gentx)[:-32-4-4], cls.gentx_before_refhash),
 526                 merkle_link=bitcoin_data.calculate_merkle_link([None] + other_transaction_hashes, 0),
 527             ))
 528             assert share.header == header # checks merkle_root
 529             return share
 530
 531         return share_info, gentx, other_transaction_hashes, get_share
 532
 533     @classmethod
 534     def get_ref_hash(cls, net, share_info, ref_merkle_link):
 535         return pack.IntType(256).pack(bitcoin_data.check_merkle_link(bitcoin_data.hash256(cls.ref_type.pack(dict(
 536             identifier=net.IDENTIFIER,
 537             share_info=share_info,
 538         ))), ref_merkle_link))
 539
 540     __slots__ = 'net peer_addr contents min_header share_info hash_link merkle_link hash share_data max_target target timestamp previous_hash new_script desired_version gentx_hash header pow_hash header_hash new_transaction_hashes time_seen'.split(' ')
 541
 542     def __init__(self, net, peer_addr, contents):
 543         self.net = net
 544         self.peer_addr = peer_addr
 545         self.contents = contents
 546
 547         self.min_header = contents['min_header']
 548         self.share_info = contents['share_info']
 549         self.hash_link = contents['hash_link']
 550         self.merkle_link = contents['merkle_link']
 551
 552         if not (2 <= len(self.share_info['share_data']['coinbase']) <= 100):
 553             raise ValueError('''bad coinbase size! %i bytes''' % (len(self.share_info['share_data']['coinbase']),))
 554
 555         if len(self.merkle_link['branch']) > 16:
 556             raise ValueError('merkle branch too long!')
 557
 558         assert not self.hash_link['extra_data'], repr(self.hash_link['extra_data'])
 559
 560         self.share_data = self.share_info['share_data']
 561         self.max_target = self.share_info['max_bits'].target
 562         self.target = self.share_info['bits'].target
 563         self.timestamp = self.share_info['timestamp']
 564         self.previous_hash = self.share_data['previous_share_hash']
 565         self.new_script = bitcoin_data.pubkey_hash_to_script2(self.share_data['pubkey_hash'])
 566         self.desired_version = self.share_data['desired_version']
 567
 568         n = set()
 569         for share_count, tx_count in self.iter_transaction_hash_refs():
 570             assert share_count < 110
 571             if share_count == 0:
 572                 n.add(tx_count)
 573         assert n == set(range(len(self.share_info['new_transaction_hashes'])))
 574
 575         self.gentx_hash = check_hash_link(
 576             self.hash_link,
 577             self.get_ref_hash(net, self.share_info, contents['ref_merkle_link']) + pack.IntType(32).pack(self.contents['last_txout_nonce']) + pack.IntType(32).pack(0),
 578             self.gentx_before_refhash,
 579         )
 580         merkle_root = bitcoin_data.check_merkle_link(self.gentx_hash, self.merkle_link)
 581         self.header = dict(self.min_header, merkle_root=merkle_root)
 582         self.pow_hash = net.PARENT.POW_FUNC(bitcoin_data.block_header_type.pack(self.header))
 583         self.hash = self.header_hash = bitcoin_data.hash256(bitcoin_data.block_header_type.pack(self.header))
 584
 585         if self.target > net.MAX_TARGET:
 586             from p2pool import p2p
 587             raise p2p.PeerMisbehavingError('share target invalid')
 588
 589         if self.pow_hash > self.target:
 590             from p2pool import p2p
 591             raise p2p.PeerMisbehavingError('share PoW invalid')
 592
 593         self.new_transaction_hashes = self.share_info['new_transaction_hashes']
 594
 595         # XXX eww
 596         self.time_seen = time.time()
 597
 598     def __repr__(self):
 599         return 'Share' + repr((self.net, self.peer_addr, self.contents))
 600
 601     def as_share(self):
 602         return dict(type=self.VERSION, contents=self.share_type.pack(self.contents))
 603
 604     def iter_transaction_hash_refs(self):
 605         return zip(self.share_info['transaction_hash_refs'][::2], self.share_info['transaction_hash_refs'][1::2])
 606
 607     def check(self, tracker):
 608         from p2pool import p2p
 609         if self.share_data['previous_share_hash'] is not None:
 610             previous_share = tracker.items[self.share_data['previous_share_hash']]
 611             if type(self) is type(previous_share):
 612                 pass
 613             elif type(self) is type(previous_share).SUCCESSOR:
 614                 if tracker.get_height(previous_share.hash) < self.net.CHAIN_LENGTH:
 615                     from p2pool import p2p
 616                     raise p2p.PeerMisbehavingError('switch without enough history')
 617
 618                 # switch only valid if 85% of hashes in [self.net.CHAIN_LENGTH*9//10, self.net.CHAIN_LENGTH] for new version
 619                 counts = get_desired_version_counts(tracker,
 620                     tracker.get_nth_parent_hash(previous_share.hash, self.net.CHAIN_LENGTH*9//10), self.net.CHAIN_LENGTH//10)
 621                 if counts.get(self.VERSION, 0) < sum(counts.itervalues())*85//100:
 622                     raise p2p.PeerMisbehavingError('switch without enough hash power upgraded')
 623             else:
 624                 raise p2p.PeerMisbehavingError('''%s can't follow %s''' % (type(self).__name__, type(previous_share).__name__))
 625
 626         other_tx_hashes = [tracker.items[tracker.get_nth_parent_hash(self.hash, share_count)].share_info['new_transaction_hashes'][tx_count] for share_count, tx_count in self.iter_transaction_hash_refs()]
 627
 628         share_info, gentx, other_tx_hashes2, get_share = self.generate_transaction(tracker, self.share_info['share_data'], self.header['bits'].target, self.share_info['timestamp'], self.share_info['bits'].target, self.contents['ref_merkle_link'], [(h, None) for h in other_tx_hashes], self.net, last_txout_nonce=self.contents['last_txout_nonce'])
 629         assert other_tx_hashes2 == other_tx_hashes
 630         if share_info != self.share_info:
 631             raise ValueError('share_info invalid')
 632         if bitcoin_data.hash256(bitcoin_data.tx_type.pack(gentx)) != self.gentx_hash:
 633             raise ValueError('''gentx doesn't match hash_link''')
 634
 635         if bitcoin_data.calculate_merkle_link([None] + other_tx_hashes, 0) != self.merkle_link:
 636             raise ValueError('merkle_link and other_tx_hashes do not match')
 637
 638         return gentx # only used by as_block
 639
 640     def get_other_tx_hashes(self, tracker):
 641         parents_needed = max(share_count for share_count, tx_count in self.iter_transaction_hash_refs()) if self.share_info['transaction_hash_refs'] else 0
 642         parents = tracker.get_height(self.hash) - 1
 643         if parents < parents_needed:
 644             return None
 645         last_shares = list(tracker.get_chain(self.hash, parents_needed + 1))
 646         return [last_shares[share_count].share_info['new_transaction_hashes'][tx_count] for share_count, tx_count in self.iter_transaction_hash_refs()]
 647
 648     def _get_other_txs(self, tracker, known_txs):
 649         other_tx_hashes = self.get_other_tx_hashes(tracker)
 650         if other_tx_hashes is None:
 651             return None # not all parents present
 652
 653         if not all(tx_hash in known_txs for tx_hash in other_tx_hashes):
 654             return None # not all txs present
 655
 656         return [known_txs[tx_hash] for tx_hash in other_tx_hashes]
 657
 658     def should_punish_reason(self, previous_block, bits, tracker, known_txs):
 659         if (self.header['previous_block'], self.header['bits']) != (previous_block, bits) and self.header_hash != previous_block and self.peer_addr is not None:
 660             return True, 'Block-stale detected! %x < %x' % (self.header['previous_block'], previous_block)
 661
 662         if self.pow_hash <= self.header['bits'].target:
 663             return -1, 'block solution'
 664
 665         other_txs = self._get_other_txs(tracker, known_txs)
 666         if other_txs is None:
 667             if self.time_seen != 0: # ignore if loaded from ShareStore
 668                 return True, 'not all txs present'
 669         else:
 670             all_txs_size = sum(bitcoin_data.tx_type.packed_size(tx) for tx in other_txs)
 671             if all_txs_size > 1000000:
 672                 return True, 'txs over block size limit'
 673
 674             new_txs_size = sum(bitcoin_data.tx_type.packed_size(known_txs[tx_hash]) for tx_hash in self.share_info['new_transaction_hashes'])
 675             if new_txs_size > 50000:
 676                 return True, 'new txs over limit'
 677
 678         return False, None
 679
 680     def as_block(self, tracker, known_txs):
 681         other_txs = self._get_other_txs(tracker, known_txs)
 682         if other_txs is None:
 683             return None # not all txs present
 684         return dict(header=self.header, txs=[self.check(tracker)] + other_txs)
 685
 686
 687
 688 class WeightsSkipList(forest.TrackerSkipList):
 689     # share_count, weights, total_weight
 690
 691     def get_delta(self, element):
 692         from p2pool.bitcoin import data as bitcoin_data
 693         share = self.tracker.items[element]
 694         att = bitcoin_data.target_to_average_attempts(share.target)
 695         return 1, {share.new_script: att*(65535-share.share_data['donation'])}, att*65535, att*share.share_data['donation']
 696
 697     def combine_deltas(self, (share_count1, weights1, total_weight1, total_donation_weight1), (share_count2, weights2, total_weight2, total_donation_weight2)):
 698         return share_count1 + share_count2, math.add_dicts(weights1, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 699
 700     def initial_solution(self, start, (max_shares, desired_weight)):
 701         assert desired_weight % 65535 == 0, divmod(desired_weight, 65535)
 702         return 0, None, 0, 0
 703
 704     def apply_delta(self, (share_count1, weights_list, total_weight1, total_donation_weight1), (share_count2, weights2, total_weight2, total_donation_weight2), (max_shares, desired_weight)):
 705         if total_weight1 + total_weight2 > desired_weight and share_count2 == 1:
 706             assert (desired_weight - total_weight1) % 65535 == 0
 707             script, = weights2.iterkeys()
 708             new_weights = {script: (desired_weight - total_weight1)//65535*weights2[script]//(total_weight2//65535)}
 709             return share_count1 + share_count2, (weights_list, new_weights), desired_weight, total_donation_weight1 + (desired_weight - total_weight1)//65535*total_donation_weight2//(total_weight2//65535)
 710         return share_count1 + share_count2, (weights_list, weights2), total_weight1 + total_weight2, total_donation_weight1 + total_donation_weight2
 711
 712     def judge(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight)):
 713         if share_count > max_shares or total_weight > desired_weight:
 714             return 1
 715         elif share_count == max_shares or total_weight == desired_weight:
 716             return 0
 717         else:
 718             return -1
 719
 720     def finalize(self, (share_count, weights_list, total_weight, total_donation_weight), (max_shares, desired_weight)):
 721         assert share_count <= max_shares and total_weight <= desired_weight
 722         assert share_count == max_shares or total_weight == desired_weight
 723         return math.add_dicts(*math.flatten_linked_list(weights_list)), total_weight, total_donation_weight
 724
 725 class OkayTracker(forest.Tracker):
 726     def __init__(self, net):
 727         forest.Tracker.__init__(self, delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 728             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 729             min_work=lambda share: bitcoin_data.target_to_average_attempts(share.max_target),
 730         )))
 731         self.net = net
 732         self.verified = forest.SubsetTracker(delta_type=forest.get_attributedelta_type(dict(forest.AttributeDelta.attrs,
 733             work=lambda share: bitcoin_data.target_to_average_attempts(share.target),
 734         )), subset_of=self)
 735         self.get_cumulative_weights = WeightsSkipList(self)
 736
 737     def attempt_verify(self, share):
 738         if share.hash in self.verified.items:
 739             return True
 740         height, last = self.get_height_and_last(share.hash)
 741         if height < self.net.CHAIN_LENGTH + 1 and last is not None:
 742             raise AssertionError()
 743         try:
 744             share.check(self)
 745         except:
 746             log.err(None, 'Share check failed:')
 747             return False
 748         else:
 749             self.verified.add(share)
 750             return True
 751
 752     def think(self, block_rel_height_func, previous_block, bits, known_txs):
 753         desired = set()
 754
 755         # O(len(self.heads))
 756         #   make 'unverified heads' set?
 757         # for each overall head, attempt verification
 758         # if it fails, attempt on parent, and repeat
 759         # if no successful verification because of lack of parents, request parent
 760         bads = set()
 761         for head in set(self.heads) - set(self.verified.heads):
 762             head_height, last = self.get_height_and_last(head)
 763
 764             for share in self.get_chain(head, head_height if last is None else min(5, max(0, head_height - self.net.CHAIN_LENGTH))):
 765                 if self.attempt_verify(share):
 766                     break
 767                 if share.hash in self.heads:
 768                     bads.add(share.hash)
 769             else:
 770                 if last is not None:
 771                     desired.add((
 772                         self.items[random.choice(list(self.reverse[last]))].peer_addr,
 773                         last,
 774                         max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 775                         min(x.target for x in self.get_chain(head, min(head_height, 5))),
 776                     ))
 777         for bad in bads:
 778             assert bad not in self.verified.items
 779             assert bad in self.heads
 780             if p2pool.DEBUG:
 781                 print "BAD", bad
 782             self.remove(bad)
 783
 784         # try to get at least CHAIN_LENGTH height for each verified head, requesting parents if needed
 785         for head in list(self.verified.heads):
 786             head_height, last_hash = self.verified.get_height_and_last(head)
 787             last_height, last_last_hash = self.get_height_and_last(last_hash)
 788             # XXX review boundary conditions
 789             want = max(self.net.CHAIN_LENGTH - head_height, 0)
 790             can = max(last_height - 1 - self.net.CHAIN_LENGTH, 0) if last_last_hash is not None else last_height
 791             get = min(want, can)
 792             #print 'Z', head_height, last_hash is None, last_height, last_last_hash is None, want, can, get
 793             for share in self.get_chain(last_hash, get):
 794                 if not self.attempt_verify(share):
 795                     break
 796             if head_height < self.net.CHAIN_LENGTH and last_last_hash is not None:
 797                 desired.add((
 798                     self.items[random.choice(list(self.verified.reverse[last_hash]))].peer_addr,
 799                     last_last_hash,
 800                     max(x.timestamp for x in self.get_chain(head, min(head_height, 5))),
 801                     min(x.target for x in self.get_chain(head, min(head_height, 5))),
 802                 ))
 803
 804         # decide best tree
 805         decorated_tails = sorted((self.score(max(self.verified.tails[tail_hash], key=self.verified.get_work), block_rel_height_func), tail_hash) for tail_hash in self.verified.tails)
 806         if p2pool.DEBUG:
 807             print len(decorated_tails), 'tails:'
 808             for score, tail_hash in decorated_tails:
 809                 print format_hash(tail_hash), score
 810         best_tail_score, best_tail = decorated_tails[-1] if decorated_tails else (None, None)
 811
 812         # decide best verified head
 813         decorated_heads = sorted(((
 814             self.verified.get_work(self.verified.get_nth_parent_hash(h, min(5, self.verified.get_height(h)))),
 815             #self.items[h].peer_addr is None,
 816             -self.items[h].should_punish_reason(previous_block, bits, self, known_txs)[0],
 817             -self.items[h].time_seen,
 818         ), h) for h in self.verified.tails.get(best_tail, []))
 819         if p2pool.DEBUG:
 820             print len(decorated_heads), 'heads. Top 10:'
 821             for score, head_hash in decorated_heads[-10:]:
 822                 print '   ', format_hash(head_hash), format_hash(self.items[head_hash].previous_hash), score
 823         best_head_score, best = decorated_heads[-1] if decorated_heads else (None, None)
 824
 825         if best is not None:
 826             best_share = self.items[best]
 827             punish, punish_reason = best_share.should_punish_reason(previous_block, bits, self, known_txs)
 828             if punish > 0:
 829                 print 'Punishing share for %r! Jumping from %s to %s!' % (punish_reason, format_hash(best), format_hash(best_share.previous_hash))
 830                 best = best_share.previous_hash
 831
 832             timestamp_cutoff = min(int(time.time()), best_share.timestamp) - 3600
 833             target_cutoff = int(2**256//(self.net.SHARE_PERIOD*best_tail_score[1] + 1) * 2 + .5) if best_tail_score[1] is not None else 2**256-1
 834         else:
 835             timestamp_cutoff = int(time.time()) - 24*60*60
 836             target_cutoff = 2**256-1
 837
 838         if p2pool.DEBUG:
 839             print 'Desire %i shares. Cutoff: %s old diff>%.2f' % (len(desired), math.format_dt(time.time() - timestamp_cutoff), bitcoin_data.target_to_difficulty(target_cutoff))
 840             for peer_addr, hash, ts, targ in desired:
 841                 print '   ', None if peer_addr is None else '%s:%i' % peer_addr, format_hash(hash), math.format_dt(time.time() - ts), bitcoin_data.target_to_difficulty(targ), ts >= timestamp_cutoff, targ <= target_cutoff
 842
 843         return best, [(peer_addr, hash) for peer_addr, hash, ts, targ in desired if ts >= timestamp_cutoff], decorated_heads
 844
 845     def score(self, share_hash, block_rel_height_func):
 846         # returns approximate lower bound on chain's hashrate in the last self.net.CHAIN_LENGTH*15//16*self.net.SHARE_PERIOD time
 847
 848         head_height = self.verified.get_height(share_hash)
 849         if head_height < self.net.CHAIN_LENGTH:
 850             return head_height, None
 851
 852         end_point = self.verified.get_nth_parent_hash(share_hash, self.net.CHAIN_LENGTH*15//16)
 853
 854         block_height = max(block_rel_height_func(share.header['previous_block']) for share in
 855             self.verified.get_chain(end_point, self.net.CHAIN_LENGTH//16))
 856
 857         return self.net.CHAIN_LENGTH, self.verified.get_delta(share_hash, end_point).work/((0 - block_height + 1)*self.net.PARENT.BLOCK_PERIOD)
 858
 859 def get_pool_attempts_per_second(tracker, previous_share_hash, dist, min_work=False, integer=False):
 860     assert dist >= 2
 861     near = tracker.items[previous_share_hash]
 862     far = tracker.items[tracker.get_nth_parent_hash(previous_share_hash, dist - 1)]
 863     attempts = tracker.get_delta(near.hash, far.hash).work if not min_work else tracker.get_delta(near.hash, far.hash).min_work
 864     time = near.timestamp - far.timestamp
 865     if time <= 0:
 866         time = 1
 867     if integer:
 868         return attempts//time
 869     return attempts/time
 870
 871 def get_average_stale_prop(tracker, share_hash, lookbehind):
 872     stales = sum(1 for share in tracker.get_chain(share_hash, lookbehind) if share.share_data['stale_info'] is not None)
 873     return stales/(lookbehind + stales)
 874
 875 def get_stale_counts(tracker, share_hash, lookbehind, rates=False):
 876     res = {}
 877     for share in tracker.get_chain(share_hash, lookbehind - 1):
 878         res['good'] = res.get('good', 0) + bitcoin_data.target_to_average_attempts(share.target)
 879         s = share.share_data['stale_info']
 880         if s is not None:
 881             res[s] = res.get(s, 0) + bitcoin_data.target_to_average_attempts(share.target)
 882     if rates:
 883         dt = tracker.items[share_hash].timestamp - tracker.items[tracker.get_nth_parent_hash(share_hash, lookbehind - 1)].timestamp
 884         res = dict((k, v/dt) for k, v in res.iteritems())
 885     return res
 886
 887 def get_user_stale_props(tracker, share_hash, lookbehind):
 888     res = {}
 889     for share in tracker.get_chain(share_hash, lookbehind - 1):
 890         stale, total = res.get(share.share_data['pubkey_hash'], (0, 0))
 891         total += 1
 892         if share.share_data['stale_info'] is not None:
 893             stale += 1
 894             total += 1
 895         res[share.share_data['pubkey_hash']] = stale, total
 896     return dict((pubkey_hash, stale/total) for pubkey_hash, (stale, total) in res.iteritems())
 897
 898 def get_expected_payouts(tracker, best_share_hash, block_target, subsidy, net):
 899     weights, total_weight, donation_weight = tracker.get_cumulative_weights(best_share_hash, min(tracker.get_height(best_share_hash), net.REAL_CHAIN_LENGTH), 65535*net.SPREAD*bitcoin_data.target_to_average_attempts(block_target))
 900     res = dict((script, subsidy*weight//total_weight) for script, weight in weights.iteritems())
 901     res[DONATION_SCRIPT] = res.get(DONATION_SCRIPT, 0) + subsidy - sum(res.itervalues())
 902     return res
 903
 904 def get_desired_version_counts(tracker, best_share_hash, dist):
 905     res = {}
 906     for share in tracker.get_chain(best_share_hash, dist):
 907         res[share.desired_version] = res.get(share.desired_version, 0) + bitcoin_data.target_to_average_attempts(share.target)
 908     return res
 909
 910 def get_warnings(tracker, best_share, net, bitcoind_warning, bitcoind_work_value):
 911     res = []
 912
 913     desired_version_counts = get_desired_version_counts(tracker, best_share,
 914         min(net.CHAIN_LENGTH, 60*60//net.SHARE_PERIOD, tracker.get_height(best_share)))
 915     majority_desired_version = max(desired_version_counts, key=lambda k: desired_version_counts[k])
 916     if majority_desired_version > (Share.SUCCESSOR if Share.SUCCESSOR is not None else Share).VOTING_VERSION and desired_version_counts[majority_desired_version] > sum(desired_version_counts.itervalues())/2:
 917         res.append('A MAJORITY OF SHARES CONTAIN A VOTE FOR AN UNSUPPORTED SHARE IMPLEMENTATION! (v%i with %i%% support)\n'
 918             'An upgrade is likely necessary. Check http://p2pool.forre.st/ for more information.' % (
 919                 majority_desired_version, 100*desired_version_counts[majority_desired_version]/sum(desired_version_counts.itervalues())))
 920
 921     if bitcoind_warning is not None:
 922         if 'This is a pre-release test build' not in bitcoind_warning:
 923             res.append('(from bitcoind) %s' % (bitcoind_warning,))
 924
 925     if time.time() > bitcoind_work_value['last_update'] + 60:
 926         res.append('''LOST CONTACT WITH BITCOIND for %s! Check that it isn't frozen or dead!''' % (math.format_dt(time.time() - bitcoind_work_value['last_update']),))
 927
 928     return res
 929
 930 def format_hash(x):
 931     if x is None:
 932         return 'xxxxxxxx'
 933     return '%08x' % (x % 2**32)
 934
 935 class ShareStore(object):
 936     def __init__(self, prefix, net):
 937         self.filename = prefix
 938         self.dirname = os.path.dirname(os.path.abspath(prefix))
 939         self.filename = os.path.basename(os.path.abspath(prefix))
 940         self.net = net
 941         self.known = None # will be filename -> set of share hashes, set of verified hashes
 942         self.known_desired = None
 943
 944     def get_shares(self):
 945         if self.known is not None:
 946             raise AssertionError()
 947         known = {}
 948         filenames, next = self.get_filenames_and_next()
 949         for filename in filenames:
 950             share_hashes, verified_hashes = known.setdefault(filename, (set(), set()))
 951             with open(filename, 'rb') as f:
 952                 for line in f:
 953                     try:
 954                         type_id_str, data_hex = line.strip().split(' ')
 955                         type_id = int(type_id_str)
 956                         if type_id == 0:
 957                             pass
 958                         elif type_id == 1:
 959                             pass
 960                         elif type_id == 2:
 961                             verified_hash = int(data_hex, 16)
 962                             yield 'verified_hash', verified_hash
 963                             verified_hashes.add(verified_hash)
 964                         elif type_id == 5:
 965                             raw_share = share_type.unpack(data_hex.decode('hex'))
 966                             if raw_share['type'] in [0, 1, 2, 3, 4, 5, 6, 7, 8]:
 967                                 continue
 968                             share = load_share(raw_share, self.net, None)
 969                             yield 'share', share
 970                             share_hashes.add(share.hash)
 971                         else:
 972                             raise NotImplementedError("share type %i" % (type_id,))
 973                     except Exception:
 974                         log.err(None, "HARMLESS error while reading saved shares, continuing where left off:")
 975         self.known = known
 976         self.known_desired = dict((k, (set(a), set(b))) for k, (a, b) in known.iteritems())
 977
 978     def _add_line(self, line):
 979         filenames, next = self.get_filenames_and_next()
 980         if filenames and os.path.getsize(filenames[-1]) < 10e6:
 981             filename = filenames[-1]
 982         else:
 983             filename = next
 984
 985         with open(filename, 'ab') as f:
 986             f.write(line + '\n')
 987
 988         return filename
 989
 990     def add_share(self, share):
 991         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
 992             if share.hash in share_hashes:
 993                 break
 994         else:
 995             filename = self._add_line("%i %s" % (5, share_type.pack(share.as_share()).encode('hex')))
 996             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
 997             share_hashes.add(share.hash)
 998         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
 999         share_hashes.add(share.hash)
1000
1001     def add_verified_hash(self, share_hash):
1002         for filename, (share_hashes, verified_hashes) in self.known.iteritems():
1003             if share_hash in verified_hashes:
1004                 break
1005         else:
1006             filename = self._add_line("%i %x" % (2, share_hash))
1007             share_hashes, verified_hashes = self.known.setdefault(filename, (set(), set()))
1008             verified_hashes.add(share_hash)
1009         share_hashes, verified_hashes = self.known_desired.setdefault(filename, (set(), set()))
1010         verified_hashes.add(share_hash)
1011
1012     def get_filenames_and_next(self):
1013         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())
1014         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)))
1015
1016     def forget_share(self, share_hash):
1017         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
1018             if share_hash in share_hashes:
1019                 share_hashes.remove(share_hash)
1020         self.check_remove()
1021
1022     def forget_verified_share(self, share_hash):
1023         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
1024             if share_hash in verified_hashes:
1025                 verified_hashes.remove(share_hash)
1026         self.check_remove()
1027
1028     def check_remove(self):
1029         to_remove = set()
1030         for filename, (share_hashes, verified_hashes) in self.known_desired.iteritems():
1031             #print filename, len(share_hashes) + len(verified_hashes)
1032             if not share_hashes and not verified_hashes:
1033                 to_remove.add(filename)
1034         for filename in to_remove:
1035             self.known.pop(filename)
1036             self.known_desired.pop(filename)
1037             os.remove(filename)
1038             print "REMOVED", filename